Avirulence effectors(Avrs),encoded by plant pathogens,can be recognized by plants harboring the corresponding resistance proteins,thereby initiating effector-triggered immunity(ETI).In susceptible plants,however,Avrs ...Avirulence effectors(Avrs),encoded by plant pathogens,can be recognized by plants harboring the corresponding resistance proteins,thereby initiating effector-triggered immunity(ETI).In susceptible plants,however,Avrs can function as effectors,facilitating infection via effector-triggered susceptibility(ETS).Mechanisms of Avr-mediated ETS remain largely unexplored.Here we report that the Magnaporthe oryzae effector Avr-PikD enters rice cells via the canonical cytoplasmic secretion pathway and suppresses rice basal defense.Avr-PikD interacts with an LSD1-like transcriptional activator AKIP30 of rice,and AKIP30 is also a positive regulator of rice immunity,whereas Avr-PikD impedes its nuclear localization and suppresses its transcriptional activity.In summary,M.oryzae delivers Avr-PikD into rice cells to facilitate ETS by inhibiting AKIP30-mediated transcriptional regulation of immune response against M.oryzae.展开更多
BACKGROUND Alveolar bone defects caused by inflammation are an urgent issue in oral implant surgery that must be solved.Regulating the various phenotypes of macrophages to enhance the inflammatory environment can sign...BACKGROUND Alveolar bone defects caused by inflammation are an urgent issue in oral implant surgery that must be solved.Regulating the various phenotypes of macrophages to enhance the inflammatory environment can significantly affect the progression of diseases and tissue engineering repair process.AIM To assess the influence of interleukin-10(IL-10)on the osteogenic differentiation of bone marrow mesenchymal stem cells(BMSCs)following their interaction with macrophages in an inflammatory environment.METHODS IL-10 modulates the differentiation of peritoneal macrophages in Wistar rats in an inflammatory environment.In this study,we investigated its impact on the proliferation,migration,and osteogenesis of BMSCs.The expression levels of signal transducer and activator of transcription 3(STAT3)and its activated form,phos-phorylated-STAT3,were examined in IL-10-stimulated macrophages.Subsequently,a specific STAT3 signaling inhibitor was used to impede STAT3 signal activation to further investigate the role of STAT3 signaling.RESULTS IL-10-stimulated macrophages underwent polarization to the M2 type through substitution,and these M2 macrophages actively facilitated the osteogenic differentiation of BMSCs.Mechanistically,STAT3 signaling plays a crucial role in the process by which IL-10 influences macrophages.Specifically,IL-10 stimulated the activation of the STAT3 signaling pathway and reduced the macrophage inflammatory response,as evidenced by its diminished impact on the osteogenic differentiation of BMSCs.CONCLUSION Stimulating macrophages with IL-10 proved effective in improving the inflammatory environment and promoting the osteogenic differentiation of BMSCs.The IL-10/STAT3 signaling pathway has emerged as a key regulator in the macrophage-mediated control of BMSCs’osteogenic differentiation.展开更多
BACKGROUND Gastric cancer(GC)is one of the most common cancer types worldwide,and its prevention and treatment methods have garnered much attention.As the active ingredient of licorice,18β-glycyrrhetinic acid(18β-GR...BACKGROUND Gastric cancer(GC)is one of the most common cancer types worldwide,and its prevention and treatment methods have garnered much attention.As the active ingredient of licorice,18β-glycyrrhetinic acid(18β-GRA)has a variety of pharmacological effects.The aim of this study was to explore the effective target of 18β-GRA in the treatment of GC,in order to provide effective ideas for the clinical prevention and treatment of GC.AIM To investigate the mechanism of 18β-GRA in inhibiting cell proliferation and promoting autophagy flux in GC cells.METHODS Whole transcriptomic analyses were used to analyze and screen differentially expressed microRNAs(miRNAs)in GC cells after 18β-GRA intervention.Lentivirus-transfected GC cells and the Cell Counting Kit-8 were used to detect cell proliferation ability,cell colony formation ability was detected by the clone formation assay,and flow cytometry was used to detect the cell cycle and apoptosis.A nude mouse transplantation tumor model of GC cells was constructed to verify the effect of miR-328-3p overexpression on the tumorigenicity of GC cells.Tumor tissue morphology was observed by hematoxylin and eosin staining,and microtubule-associated protein light chain 3(LC3)expression was detected by immunohistochemistry.TransmiR,STRING,and miRWalk databases were used to predict the relationship between miR-328-3p and signal transducer and activator of transcription 3(STAT3)-related information.Expression of STAT3 mRNA and miR-328-3p was detected by quantitative polymerase chain reaction(qPCR)and the expression levels of STAT3,phosphorylated STAT3(p-STAT3),and LC3 were detected by western blot analysis.The targeted relationship between miR-328-3p and STAT3 was detected using the dual-luciferase reporter gene system.AGS cells were infected with monomeric red fluorescent protein-green fluorescent protein-LC3 adenovirus double label.LC3 was labeled and autophagy flow was observed under a confocal laser microscope.RESULTS The expression of miR-328-3p was significantly upregulated after 18β-GRA intervention in AGS cells(P=4.51E-06).Overexpression of miR-328-3p inhibited GC cell proliferation and colony formation ability,arrested the cell cycle in the G0/G1 phase,promoted cell apoptosis,and inhibited the growth of subcutaneous tumors in BALB/c nude mice(P<0.01).No obvious necrosis was observed in the tumor tissue in the negative control group(no drug intervention or lentivirus transfection)and vector group(the blank vector for lentivirus transfection),and more cells were loose and necrotic in the miR-328-3p group.Bioinformatics tools predicted that miR-328-3p has a targeting relationship with STAT3,and STAT3 was closely related to autophagy markers such as p62.After overexpressing miR-328-3p,the expression level of STAT3 mRNA was significantly decreased(P<0.01)and p-STAT3 was downregulated(P<0.05).The dual-luciferase reporter gene assay showed that the luciferase activity of miR-328-3p and STAT33’untranslated regions of the wild-type reporter vector group was significantly decreased(P<0.001).Overexpressed miR-328-3p combined with bafilomycin A1(Baf A1)was used to detect the expression of LC3 II.Compared with the vector group,the expression level of LC3 II in the overexpressed miR-328-3p group was downregulated(P<0.05),and compared with the Baf A1 group,the expression level of LC3 II in the overexpressed miR-328-3p+Baf A1 group was upregulated(P<0.01).The expression of LC3 II was detected after intervention of 18β-GRA in GC cells,and the results were consistent with the results of miR-328-3p overexpression(P<0.05).Additional studies showed that 18β-GRA promoted autophagy flow by promoting autophagosome synthesis(P<0.001).qPCR showed that the expression of STAT3 mRNA was downregulated after drug intervention(P<0.05).Western blot analysis showed that the expression levels of STAT3 and p-STAT3 were significantly downregulated after drug intervention(P<0.05).CONCLUSION 18β-GRA promotes the synthesis of autophagosomes and inhibits GC cell proliferation by regulating the miR-328-3p/STAT3 signaling pathway.展开更多
Pancreatic ductal adenocarcinoma(PDAC) remains a deadly disease with no efficacious treatment options. PDAC incidence is projected to increase, which may be caused at least partially by the obesity epidemic. Significa...Pancreatic ductal adenocarcinoma(PDAC) remains a deadly disease with no efficacious treatment options. PDAC incidence is projected to increase, which may be caused at least partially by the obesity epidemic. Significantly enhanced efforts to prevent or intercept this cancer are clearly warranted. Oncogenic KRAS mutations are recognized initiating events in PDAC development, however, they are not entirely sufficient for the development of fully invasive PDAC.Additional genetic alterations and/or environmental, nutritional, and metabolic signals, as present in obesity, type-2 diabetes mellitus, and inflammation, are required for full PDAC formation. We hypothesize that oncogenic KRAS increases the intensity and duration of the growth-promoting signaling network.Recent exciting studies from different laboratories indicate that the activity of the transcriptional co-activators Yes-associated protein(YAP) and WW-domaincontaining transcriptional co-activator with PDZ-binding motif(TAZ) play a critical role in the promotion and maintenance of PDAC operating as key downstream target of KRAS signaling. While initially thought to be primarily an effector of the tumor-suppressive Hippo pathway, more recent studies revealed that YAP/TAZ subcellular localization and co-transcriptional activity is regulated by multiple upstream signals. Overall, YAP has emerged as a central node of transcriptional convergence in growth-promoting signaling in PDAC cells. Indeed, YAP expression is an independent unfavorable prognostic marker for overall survival of PDAC. In what follows, we will review studies implicating YAP/TAZ in pancreatic cancer development and consider different approaches to target these transcriptional regulators.展开更多
The peaT1 gene fragment was amplified from pGEM-6p-l-peaT1 by PCR, and recovered target gene was cloned into pLexA vector. After digestion and sequencing, the bait vector pLexA-peaT1 was transformed into yeast strain ...The peaT1 gene fragment was amplified from pGEM-6p-l-peaT1 by PCR, and recovered target gene was cloned into pLexA vector. After digestion and sequencing, the bait vector pLexA-peaT1 was transformed into yeast strain EGY48 [p8op-lacZ] by PEG/LiAC, and the transcriptional activity of bait vector was detected. The results showed that recombinant bait plasmid pLexA-PEMG1 was constructed, for the two bands of recombinant bait plasmid in agarose gel eleetrophoresis were expected after digesting by restriction endonuclease EcoR I and Xho I. Therefore, the recombinant bait plasmid could be used in yeast two-hybrid system to screen a cDNA library.展开更多
Signal transducer and activator of transcription 3(STAT3), a member of the STAT family, is a key regulator of many physiological and pathological processes. Significant progress has been made in understanding the tran...Signal transducer and activator of transcription 3(STAT3), a member of the STAT family, is a key regulator of many physiological and pathological processes. Significant progress has been made in understanding the transcriptional control, posttranslational modification, cellular localization and functional regulation of STAT3. STAT3 can translocate into the nucleus and bind to specific promoter sequences, thereby exerting transcriptional regulation. Recent studies have shown that STAT3 can also translocate into mitochondria, participating in aerobic respiration and apoptosis. In addition, STAT3 plays an important role in inflammation and tumorigenesis by regulating cell proliferation, differentiation and metabolism. Conditional knockout mouse models make it possible to study the physiological function of STAT3 in specific tissues and organs. This review summarizes the latest advances in the understanding of the expression, regulation and function of STAT3 in physiological and tumorigenic processes.展开更多
AIM:To investigate the roles and mechanism of signal transducer and activator of transcription 3 (STAT3) in invasion of human colon cancer cells by RNA interference. METHODS: Small interfering RNA (siRNA) targeting Si...AIM:To investigate the roles and mechanism of signal transducer and activator of transcription 3 (STAT3) in invasion of human colon cancer cells by RNA interference. METHODS: Small interfering RNA (siRNA) targeting Signal transducer and activator of transcription 3 (STAT3) was transfected into HT29 colon cancer cells. STAT3 protein level and DNA-binding activity of STAT3 was evaluated by western blotting and electrophoretic mobility shift assay (EMSA), respectively. We studied the anchorage-independent growth using colony formation in soft agar, and invasion using the boyden chamber model, anoikis using DNA fragmentation assay and terminal deoxynucleotidyltransferase-mediated dUTP nick-end labeling (TUNEL), respectively. Western blot assay was used to observe the protein expression of Bcl-xL and survivin in colon cancer HT29 cells. RESULTS: RNA interference (RNAi) mediated by siRNA leads to suppression of STAT3 expression in colon cancer cell lines. Suppression of STAT3 expression by siRNA could inhibit anchorage-independent growth, and invasion ability, and induces anoikis in the colon cancer cell line HT29. It has been shown that knockdown of STAT3 expression by siRNA results in a reduction in expression of Bcl-xL and survivin in HT29 cells. CONCLUSION: These results suggest that STAT3 siRNA can inhibit the invasion ability of colon cancer cells through inducing anoikis, which antiapoptotic genes survivin and Bcl-xL contribute to regulation of anoikis.These studies indicate STAT3 siRNA could be a useful therapeutic tool for the treatment of colon cancer.展开更多
BACKGROUND Study shows that signal transducer and activator of transcription 3(STAT3) can increase the Warburg effect by stimulating hexokinase 2 in breast cancer and upregulate lactate dehydrogenase A and pyruvate de...BACKGROUND Study shows that signal transducer and activator of transcription 3(STAT3) can increase the Warburg effect by stimulating hexokinase 2 in breast cancer and upregulate lactate dehydrogenase A and pyruvate dehydrogenase kinase 1 in myeloma. STAT3 and pyruvate kinase M2(PKM2) can also be activated and enhance the Warburg effect in hepatocellular carcinoma. Precancerous lesions are critical to human and rodent hepatocarcinogenesis. However, the underlying molecular mechanism for the development of liver precancerous lesions remains unknown. We hypothesized that STAT3 promotes the Warburg effect possibly by upregulating p-PKM2 in liver precancerous lesions in rats.AIM To investigate the mechanism of the Warburg effect in liver precancerous lesions in rats.METHODS A model of liver precancerous lesions was established by a modified Solt-Farber method. The liver pathological changes were observed by HE staining and immunohistochemistry. The transformation of WB-F344 cells induced with Nmethyl-N'-nitro-N-nitrosoguanidine and hydrogen peroxide was evaluated by the soft agar assay and aneuploidy. The levels of glucose and lactate in the tissue and culture medium were detected with a spectrophotometer. The protein levels of glutathione S-transferase-π, proliferating cell nuclear antigen(PCNA), STAT3,and PKM2 were examined by Western blot and immunofluorescence.RESULTS We found that the Warburg effect was increased in liver precancerous lesions in rats. PKM2 and p-STAT3 were upregulated in activated oval cells in liverprecancerous lesions in rats. The Warburg effect, p-PKM2, and p-STAT3 expression were also increased in transformed WB-F344 cells. STAT3 activation promoted the clonal formation rate, aneuploidy, alpha-fetoprotein expression,PCNA expression, G1/S phase transition, the Warburg effect, PKM2 phosphorylation, and nuclear translocation in transformed WB-F344 cells.Moreover, the Warburg effect was inhibited by stattic, a specific inhibitor of STAT3, and further reduced in transformed WB-F344 cells after the intervention for PKM2.CONCLUSION The Warburg effect is initiated in liver precancerous lesions in rats. STAT3 activation promotes the Warburg effect by enhancing the phosphorylation of PKM2 in transformed WB-F344 cells.展开更多
One possible mechanism suggested for somaclonal variation is the activation of transposable elements. The activation of retrotransposons by stresses and external changes is commonly observed in plants. In previous stu...One possible mechanism suggested for somaclonal variation is the activation of transposable elements. The activation of retrotransposons by stresses and external changes is commonly observed in plants. In previous study, we isolated the reverse transcriptase (RT) gene sequences of Ty 1-copia retrotransposons from tissue culture strawberry (Fragaria x ananassa) plant, but not the transcriptionally active sequence. For further understanding the relationship between retrotransposon and somaclonal varation, in this study, we isolated the transcriptionally active RT gene sequences from strawberry plants subjected to different abiotic stresses. These retrotransposons were activated by spraying strawberry leaves with 2 mmol L^-1 salicylic acid (SA), 50 mmol L^-1 methyl jasmonate (MeJA), 50 mmol L^-1 abscisic acid (ABA), 50 mmol L^-1 2,4- dichlorophenoxyacetic acid (2,4-D) or by inducing callus growth in 2 types of MS media: first medium supplemented with 0.5 mg L^-1 6-benzylaminopurine (6-BA), 0.5 mg L^-1 gibberellic acid (GA3), 1.0 mg L^-1 thidiazuron (TDZ), and 0.1 mg L^-1 2,4-D, and the second medium supplemented with 0.5 mg L^-1 6-BA, 0.5 mg L^-1 GA3, 2.0 mg L^-1 TDZ, and 0.02 mg L^-1 indole butyric acid (1BA). Analysis of gene sequences of 17 RTs revealed that none of them contained stop codons and/or indels disrupting the reading frame. These different stress-origin transcriptionally active RTs were remarkably similar to each other- FATEXP2-8 and FATEYS9-7 showed 100% sequence identity. Analysis of pylogenetic of these transcriptionally active RTs and the RT sequences from genome showed that there were close phylogenetic relationships of most of the transcriptionally active RTs. The results of this study have contributed to the background information necessary for future studies for evaluating the relationship between retrotransposons and somaclonal variation.展开更多
AIM: To explore the effect of silencing of signal transducer and activator of transcription 3 (STAT3) expression by RNA interference (RNAi) on growth of human hepatocellular carcinoma (HCC) in tumorbearing nude...AIM: To explore the effect of silencing of signal transducer and activator of transcription 3 (STAT3) expression by RNA interference (RNAi) on growth of human hepatocellular carcinoma (HCC) in tumorbearing nude mice in vivo.METHODS: To construct the recombinant plasmid of pSilencer 3.0-H1-STAT3-siRNA-GFP (pSHI-siRNA- STAT3) and establish the tumor-bearing nude mouse model of the HCC cell line SMMC7721, we used intratumoral injection together with electroblotting to transfect the recombinant plasmid pSHI-siRNA- STAT3 into the transplanted tumor. The weight of the nude mice and tumor volumes were recorded. STAT3 gene transcription was detected by semi-quantitative reverse transcription polymerase chain reaction (RT- PCR). Level of protein expression and location of STAT3 were determined by Western blotting and immunohistochemical staining. STAT3-related genes such as survivin, c-myc, VEGF, p53 and caspase3 mRNA and protein expression were detected in tumor tissues at the same time. The terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assay was used to detect apoptosis of tumor cells.RESULTS: The weight of the treated nude mice increased, and the tumor volume decreased markedly compared with those of the mock-treated and negative control groups (P 〈 0.01). The results of RT-PCR and Western blotting showed that mRNA and protein levels of STAT3 declined markedly in the treated group. The change in STAT3-related gene expression in tumor tissues at the mRNA and protein level also varied, the expression of survivin, VEGF and c-myc were obviously reduced, and expression of p53 and caspase3 increased (P 〈 0.01). Most of the tumor tissue ceils in the treated group developed apoptosis that was detected by TUNEL assay.CONCLUSION: Silencing of STAT3 expression by RNAi significantly inhibits expression of STAT3 mRNA and protein, and suppresses growth of human HCC in tumor-bearing nude mice. The mechanism may be related to down-regulation of survivin, VEGF and c-myc and up-regulation of p53 and caspase3 expression. Accordingly, the STAT3 gene may act as an important and effective target in gene therapy of HCC.展开更多
Hepatocellular carcinoma is one of the most common cancers worldwide,and a leading cause of cancer-related death.Owing to unsatisfactory clinical outcomes under the current standard of care,there is a need to search f...Hepatocellular carcinoma is one of the most common cancers worldwide,and a leading cause of cancer-related death.Owing to unsatisfactory clinical outcomes under the current standard of care,there is a need to search for and identify novel and potent therapeutic targets to improve patient outcomes.Sorafenib is the first and only approved targeted therapy for the treatment of hepatocellular carcinoma.Besides functioning as a multiple tyrosine kinase,sorafenib also acts via a kinase-independent mechanism to target signal transducer and activator of transcription 3(STAT3) signaling in hepatocellular carcinoma cells.STAT3 is a key regulator of inflammation,cell survival,and tumorigenesis of liver cells,and the high percentage of hepatocellular carcinoma cells with constitutively active STAT3 justifies targeting it for the development of novel therapeutics.Sorafenib inactivates STAT3 and STAT3-related signaling by inducing a conformational change in and releasing the autoinhibition of Src homology region 2 domaincontaining phosphatase-1.This phosphatase negatively regulates STAT3 activity,which leads to the subsequent apoptosis of cancer cells.The novel anti-cancer property of sorafenib will be discussed in this review,not only adding information regarding its mechanism of action but also providing an innovative approach for the development of cancer therapeutics in the future.展开更多
Psoriasis is a chronic autoimmune disease featured by patches on the skin.It is caused by malfunction of immune cells and keratinocytes with inflammation as one of its key features.Apigenin(API)is a natural flavonoid ...Psoriasis is a chronic autoimmune disease featured by patches on the skin.It is caused by malfunction of immune cells and keratinocytes with inflammation as one of its key features.Apigenin(API)is a natural flavonoid with anti-inflammatory and immunoregulatory properties.Therefore,we speculated that API can ameliorate psoriasis,and determined its effect on the development of psoriasis by using imiquimod(IMQ)-induced psoriasis mouse model.Our results showed that API attenuated IMQ-induced phenotypic changes,such as erythema,scaling and epidermal thickening,and improved splenic hyperplasia.Abnormal differentiation of immune cells was restored in API-treated mice.Mechanistically,we revealed that API is a key regulator of signal transducer activator of transcription 3(STAT3).API regulated immune responses by reducing interleukin-23(IL-23)/STAT3/IL-17A axis.Moreover,it suppressed IMQ-caused cell hyperproliferation by inactivating STAT3 through regulation of extracellular signal-regulated kinase 1/2 and nuclear factor-κB(NF-κB)pathway.Furthermore,API reduced expression of inflammatory cytokines through inactivation of NF-κB.Taken together,our study demonstrates that API can ameliorate psoriasis and may be considered as a strategy for psoriasis treatment.展开更多
Chondrocytes and osteoblasts differentiate from a common mesenchymal precursor, the osteochondroprogenitor(OCP), and help build the vertebrate skeleton. The signaling pathways that control lineage commitment for OCP...Chondrocytes and osteoblasts differentiate from a common mesenchymal precursor, the osteochondroprogenitor(OCP), and help build the vertebrate skeleton. The signaling pathways that control lineage commitment for OCPs are incompletely understood. We asked whether the ubiquitously expressed protein-tyrosine phosphatase SHP2(encoded by Ptpn11) affects skeletal lineage commitment by conditionally deleting Ptpn11 in mouse limb and head mesenchyme using "Cre-lox P"-mediated gene excision.SHP2-deficient mice have increased cartilage mass and deficient ossification, suggesting that SHP2-deficient OCPs become chondrocytes and not osteoblasts. Consistent with these observations, the expression of the master chondrogenic transcription factor SOX9 and its target genes Acan, Col2a1, and Col10a1 were increased in SHP2-deficient chondrocytes, as revealed by gene expression arrays, q RT-PCR, in situ hybridization, and immunostaining. Mechanistic studies demonstrate that SHP2 regulates OCP fate determination via the phosphorylation and SUMOylation of SOX9, mediated at least in part via the PKA signaling pathway. Our data indicate that SHP2 is critical for skeletal cell lineage differentiation and could thus be a pharmacologic target for bone and cartilage regeneration.展开更多
Signal transducer and activator of transcription(STAT)is a unique protein family that binds to DNA,coupled with tyrosine phosphorylation signaling pathways,acting as a transcriptional regulator to mediate a variety ...Signal transducer and activator of transcription(STAT)is a unique protein family that binds to DNA,coupled with tyrosine phosphorylation signaling pathways,acting as a transcriptional regulator to mediate a variety of biological effects.Cerebral ischemia and reperfusion can activate STATs signaling pathway,but no studies have confirmed whether STAT activation can be verified by diffusion-weighted magnetic resonance imaging(DWI)in rats after cerebral ischemia/reperfusion.Here,we established a rat model of focal cerebral ischemia injury using the modified Longa method.DWI revealed hyperintensity in parts of the left hemisphere before reperfusion and a low apparent diffusion coefficient.STAT3 protein expression showed no significant change after reperfusion,but phosphorylated STAT3 expression began to increase after 30 minutes of reperfusion and peaked at 24 hours.Pearson correlation analysis showed that STAT3 activation was correlated positively with the relative apparent diffusion coefficient and negatively with the DWI abnormal signal area.These results indicate that DWI is a reliable representation of the infarct area and reflects STAT phosphorylation in rat brain following focal cerebral ischemia/reperfusion.展开更多
AIM: To study the effect of Hepatitis C virus nonstructural 5A (HCV NSSA) on IFNα induced signal transducer and activator of transcription-1 (STAT1) phosphorylation and nuclear translocation.METHODS: Expression...AIM: To study the effect of Hepatitis C virus nonstructural 5A (HCV NSSA) on IFNα induced signal transducer and activator of transcription-1 (STAT1) phosphorylation and nuclear translocation.METHODS: Expression of STAT1 Tyr701 phosphorylation at different time points was confirmed by Western blot, and the time point when p-STAT1 expressed most, was taken as the IFN induction time for further studies. Immunocytochemistry was used to confirm the successful transient transfection of NS5A expression plasmid. Immunofluorescene was performed to observe if there was any difference in IFNα-induced STAT1 phosphorylation and nuclear translocation between HCV NSSA-expressed and non-HCV NSSA-expressed cells. Western blot was used to compare the phosphorylated STAT1 protein of the cells.RESULTS: Expression of HCV NS5A was found in the cytoplasm of pCNS5A-transfected Huh7 cells, but not in the PRC/ CMV transfected or non-transfected cells, STAT1 Tyr701 phosphorylation was found strongest in 30 min of IFN induction, STAT1 phosphorylation and nuclear import were much less in the presence of HCV NS5A protein in contrast to pRC/CMV-transfected and non-transfected cells under fluorescent microscopy, which was further confirmed by Western blot.CONCLUSION: HCV NSSA expression plasmid is successfully transfected into Huh7 cells and HCV NS5A protein is expressed in the cytoplasm of the cells. IFN-α is able to induce STAT1 phosphrylation and nuclear translocation, and this effect is inhibited by HCV NS5A protein, which might be another possible resistance mechanism to interferon alpha therapy.展开更多
The Janus kinase and signal transducer and activator of transcription (JAK/STAT) signal transduction pathway is involved in sepsis-induced functional damage to the heart, liver, kidney, and other organs. However, th...The Janus kinase and signal transducer and activator of transcription (JAK/STAT) signal transduction pathway is involved in sepsis-induced functional damage to the heart, liver, kidney, and other organs. However, the cellular and molecular mechanisms underlying sepsis-induced brain damage remain elusive. In the present study, we found severe loss of neurons in the hippocampal CA1 region in rats with sepsis-induced brain damage following intraperitoneal injection of endotoxin, The expression of toll-like receptor 4, tumor necrosis factor a, and interleukin-6 was significantly increased in brain tissues following lipopolysaccharide exposure. AG490 (JAK2 antagonist) and rapamycin (STAT3 antagonist) significantly reduced neuronal loss and suppressed the increased expression of toll-like receptor 4, tumor necrosis factor a, and interleukin-6 in the hippocampal CA1 region in sepsis-induced brain damaged rats. Overall, these data suggest that blockade of the JAK/STAT signal transduction pathway is neuroprotective in sepsis-induced brain damage via the inhibition of toll-like receptor 4, tumor necrosis factor a, and interleukin-6 exoression.展开更多
The interplay between mechanoresponses and a broad range of fundamental biological processes, such as cell cycle progression,growth and differentiation, has been extensively investigated. However, metabolic regulation...The interplay between mechanoresponses and a broad range of fundamental biological processes, such as cell cycle progression,growth and differentiation, has been extensively investigated. However, metabolic regulation in mechanobiology remains largely unexplored. Here, we identified glucose transporter 1(GLUT1)—the primary glucose transporter in various cells—as a novel mechanosensitive gene in orthodontic tooth movement(OTM). Using an in vivo rat OTM model, we demonstrated the specific induction of Glut1 proteins on the compressive side of a physically strained periodontal ligament. This transcriptional activation could be recapitulated in in vitro cultured human periodontal ligament cells(PDLCs), showing a time-and dose-dependent mechanoresponse. Importantly, application of GLUT1 specific inhibitor WZB117 greatly suppressed the efficiency of orthodontic tooth movement in a mouse OTM model, and this reduction was associated with a decline in osteoclastic activities. A mechanistic study suggested that GLUT1 inhibition affected the receptor activator for nuclear factor-κ B Ligand(RANKL)/osteoprotegerin(OPG)system by impairing compressive force-mediated RANKL upregulation. Consistently, pretreatment of PDLCs with WZB117 severely impeded the osteoclastic differentiation of co-cultured RAW264.7 cells. Further biochemical analysis indicated mutual regulation between GLUT1 and the MEK/ERK cascade to relay potential communication between glucose uptake and mechanical stress response. Together, these cross-species experiments revealed the transcriptional activation of GLUT1 as a novel and conserved linkage between metabolism and bone remodelling.展开更多
SNF1-related protein kinase 2(SnRK2)family members are essential components of the plant abscisic acid(ABA)signaling pathway initiated by osmotic stress and triggering a drought stress response.This study characterize...SNF1-related protein kinase 2(SnRK2)family members are essential components of the plant abscisic acid(ABA)signaling pathway initiated by osmotic stress and triggering a drought stress response.This study characterized the molecular properties of TaSnRK2.4 and its function in mediating adaptation to drought in Triticum aestivum.Transcripts of TaSnRK2.4 were upregulated upon drought and ABA signaling and associated with drought-and ABA-responsive cis-elements ABRE and DRE,and MYB and MYC binding sites in the promoter as indicated by reporter GUS protein staining and activity driven by truncations of the promoter.Yeast two-hybrid,BiFC,and Co-IP assays indicated that TaSnRK2.4 protein interacts with TaPP2C01 and an ABF transcription factor(TF)TaABF2.The results suggested that TaSnRK2.4 forms a functional TaPP2C01-TaSnRK2.4-TaABF2 module with its upstream and downstream partners.Transgene analysis revealed that TaSnRK2.4 and TaABF2 positively regulate drought tolerance whereas TaPP2C01 acts negatively by modulating stomatal movement,osmotic adjustment,reactive oxygen species(ROS)homeostasis,and root morphology.Expression analysis,yeast one-hybrid,and transcriptional activation assays indicated that several osmotic stress-responsive genes,including TaSLAC1-4,TaP5CS3,TaSOD5,TaCAT1,and TaPIN4,are regulated by TaABF2.Transgene analysis verified their functions in positively regulating stomatal movement(TaSLAC1-4),proline accumulation(TaP5CS3),SOD activity(TaSOD5),CAT activity(TaCAT1),and root morphology(TaPIN4).There were high correlations between plant biomass and yield with module transcripts in a wheat variety panel cultivated under drought conditions in the field.Our findings provide insights into understanding plant drought response underlying the SnRK2 signaling pathway in common wheat.展开更多
Objective:To investigate the molecular mechanism and identify potential drugs for subthreshold depression(SD),and elucidate the detalied mechanism of Danzhi Xiaoyao powder(DZXY)in SD.Methods:Using RNA-sequencing,we id...Objective:To investigate the molecular mechanism and identify potential drugs for subthreshold depression(SD),and elucidate the detalied mechanism of Danzhi Xiaoyao powder(DZXY)in SD.Methods:Using RNA-sequencing,we identified differentially expressed genes(DEGs)in leukocytes of SD compared to healthy controls,deciphered their functions and pathways,and identified the hub genes of SD.We also assessed changes in leukocyte transcription factor activity in patients with SD using the TELis platform.The Connectivity Map database was retrieved to screen candidate drugs for SD.Based on network pharmacology,we elucidated the"multi-component,multi-target,and multi-pathway"mechanism of DZXY in the treatment of SD.Results:We identified 1080 DEGs(padj<0.05 and|log2(fold change)l≥1&protein coding)in the leukocytes of patients with SD.These DEGs,including hub genes,were primarily involved in immune and inflammatory response-related processes.Transcription factor activity analysis revealed similarities between the leukocyte transcriptome profile in SD and the conserved transcriptional response to adversities in immune cells.Connectivity Map analysis identified 28 potential drugs for SD treatment,particularly SB-202190 and TWS-119.Constructing the"Direct Compounds-Direct Targets-Pathways"network for DZXY and SD revealed the curative mechanisms of DZXY in SD,primarily including inflammatory response,lipid metabolism,immune response,and other processes.Conclusion:These results provide new insights into the characteristics and functional changes of leukocytes in SD,partially illustrate the pathogenesis of SD,and suggest potential drugs for SD.The curative mechanisms of DZXY in SD are also partially elucidated.展开更多
OBJECTIVE: To explore the feasibility of cloning of the hepatocyte receptor interacting with the Pre Slprotein of HBV by two-hybrid system.METHODS: Yeast expression plasmids encoding fusion proteins of full length or ...OBJECTIVE: To explore the feasibility of cloning of the hepatocyte receptor interacting with the Pre Slprotein of HBV by two-hybrid system.METHODS: Yeast expression plasmids encoding fusion proteins of full length or portions of Pre Sl ofHBV and DNA binding domain of yeast protein GAL4 were constructed and used to transform yeastreporter strain SFY526. Reporter gene product β-galactosidase activity was assayed as a measure oftranscriptional activation in yeast, Mammalian expression plasmid encoding fusion proteins of full lengthPre Sl and DNA binding domain of GAL4 was constructed and used to cotransfect hepatoma cell lineHuh-7 together with CAT reporter plasmid. Cell extracts were assayed for CAT activity by thin-layerchromatography.RESULTS: The fusion proteins of full length Pre Sl protein and GAL4 DNA binding domain presentedtranscriptional activation function in yeast. The transcription activating sequence was localized to the 21 to47 amino acids of Pre Sl protein. Fusion proteins of full length Pre Sl and GAL4 DNA binding domaindid not show transcriptional activation function in mammalian cells.CONCLUSIONS: The transcription activating sequence of HBV Pre Sl protein in yeast overlaps thehepatocyte receptor binding site. The transcriptional activation function of HBV Pre Sl protein in yeastmay prevent researchers from using yeast two-hybrid system to clone HBV receptor interacting with Pre Slprotein. However, the Pre Sl protein does not show transcriptional activation function in mammaliancells. Mammalian two-hybrid system may be a practical method to clone the HBV hepatocyte receptorinteracting with Pre Sl protein.展开更多
基金supported by grants from the National Natural Science Foundation of China(31401692,31901960,32272513,32001976)the Natural Science Foundation of Fujian Province(2019J01766,2023J011418,2020J05177)+3 种基金Fujian Provincial Science and Technology Key Project(2022NZ030014)External Cooperation Program of Fujian Academy of Agricultural Sciences(DWHZ-2024-23)State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crop Opening Project(SKL2019005)Project of Fujian Provincial Department of Education(JAT190627)。
文摘Avirulence effectors(Avrs),encoded by plant pathogens,can be recognized by plants harboring the corresponding resistance proteins,thereby initiating effector-triggered immunity(ETI).In susceptible plants,however,Avrs can function as effectors,facilitating infection via effector-triggered susceptibility(ETS).Mechanisms of Avr-mediated ETS remain largely unexplored.Here we report that the Magnaporthe oryzae effector Avr-PikD enters rice cells via the canonical cytoplasmic secretion pathway and suppresses rice basal defense.Avr-PikD interacts with an LSD1-like transcriptional activator AKIP30 of rice,and AKIP30 is also a positive regulator of rice immunity,whereas Avr-PikD impedes its nuclear localization and suppresses its transcriptional activity.In summary,M.oryzae delivers Avr-PikD into rice cells to facilitate ETS by inhibiting AKIP30-mediated transcriptional regulation of immune response against M.oryzae.
文摘BACKGROUND Alveolar bone defects caused by inflammation are an urgent issue in oral implant surgery that must be solved.Regulating the various phenotypes of macrophages to enhance the inflammatory environment can significantly affect the progression of diseases and tissue engineering repair process.AIM To assess the influence of interleukin-10(IL-10)on the osteogenic differentiation of bone marrow mesenchymal stem cells(BMSCs)following their interaction with macrophages in an inflammatory environment.METHODS IL-10 modulates the differentiation of peritoneal macrophages in Wistar rats in an inflammatory environment.In this study,we investigated its impact on the proliferation,migration,and osteogenesis of BMSCs.The expression levels of signal transducer and activator of transcription 3(STAT3)and its activated form,phos-phorylated-STAT3,were examined in IL-10-stimulated macrophages.Subsequently,a specific STAT3 signaling inhibitor was used to impede STAT3 signal activation to further investigate the role of STAT3 signaling.RESULTS IL-10-stimulated macrophages underwent polarization to the M2 type through substitution,and these M2 macrophages actively facilitated the osteogenic differentiation of BMSCs.Mechanistically,STAT3 signaling plays a crucial role in the process by which IL-10 influences macrophages.Specifically,IL-10 stimulated the activation of the STAT3 signaling pathway and reduced the macrophage inflammatory response,as evidenced by its diminished impact on the osteogenic differentiation of BMSCs.CONCLUSION Stimulating macrophages with IL-10 proved effective in improving the inflammatory environment and promoting the osteogenic differentiation of BMSCs.The IL-10/STAT3 signaling pathway has emerged as a key regulator in the macrophage-mediated control of BMSCs’osteogenic differentiation.
基金Ningxia Medical University Project,No. XZ2021005Ningxia Natural Science Foundation,Nos. 2022AAC03144 and 2022AAC02039National Natural Science Foundation of China,No. 82260879
文摘BACKGROUND Gastric cancer(GC)is one of the most common cancer types worldwide,and its prevention and treatment methods have garnered much attention.As the active ingredient of licorice,18β-glycyrrhetinic acid(18β-GRA)has a variety of pharmacological effects.The aim of this study was to explore the effective target of 18β-GRA in the treatment of GC,in order to provide effective ideas for the clinical prevention and treatment of GC.AIM To investigate the mechanism of 18β-GRA in inhibiting cell proliferation and promoting autophagy flux in GC cells.METHODS Whole transcriptomic analyses were used to analyze and screen differentially expressed microRNAs(miRNAs)in GC cells after 18β-GRA intervention.Lentivirus-transfected GC cells and the Cell Counting Kit-8 were used to detect cell proliferation ability,cell colony formation ability was detected by the clone formation assay,and flow cytometry was used to detect the cell cycle and apoptosis.A nude mouse transplantation tumor model of GC cells was constructed to verify the effect of miR-328-3p overexpression on the tumorigenicity of GC cells.Tumor tissue morphology was observed by hematoxylin and eosin staining,and microtubule-associated protein light chain 3(LC3)expression was detected by immunohistochemistry.TransmiR,STRING,and miRWalk databases were used to predict the relationship between miR-328-3p and signal transducer and activator of transcription 3(STAT3)-related information.Expression of STAT3 mRNA and miR-328-3p was detected by quantitative polymerase chain reaction(qPCR)and the expression levels of STAT3,phosphorylated STAT3(p-STAT3),and LC3 were detected by western blot analysis.The targeted relationship between miR-328-3p and STAT3 was detected using the dual-luciferase reporter gene system.AGS cells were infected with monomeric red fluorescent protein-green fluorescent protein-LC3 adenovirus double label.LC3 was labeled and autophagy flow was observed under a confocal laser microscope.RESULTS The expression of miR-328-3p was significantly upregulated after 18β-GRA intervention in AGS cells(P=4.51E-06).Overexpression of miR-328-3p inhibited GC cell proliferation and colony formation ability,arrested the cell cycle in the G0/G1 phase,promoted cell apoptosis,and inhibited the growth of subcutaneous tumors in BALB/c nude mice(P<0.01).No obvious necrosis was observed in the tumor tissue in the negative control group(no drug intervention or lentivirus transfection)and vector group(the blank vector for lentivirus transfection),and more cells were loose and necrotic in the miR-328-3p group.Bioinformatics tools predicted that miR-328-3p has a targeting relationship with STAT3,and STAT3 was closely related to autophagy markers such as p62.After overexpressing miR-328-3p,the expression level of STAT3 mRNA was significantly decreased(P<0.01)and p-STAT3 was downregulated(P<0.05).The dual-luciferase reporter gene assay showed that the luciferase activity of miR-328-3p and STAT33’untranslated regions of the wild-type reporter vector group was significantly decreased(P<0.001).Overexpressed miR-328-3p combined with bafilomycin A1(Baf A1)was used to detect the expression of LC3 II.Compared with the vector group,the expression level of LC3 II in the overexpressed miR-328-3p group was downregulated(P<0.05),and compared with the Baf A1 group,the expression level of LC3 II in the overexpressed miR-328-3p+Baf A1 group was upregulated(P<0.01).The expression of LC3 II was detected after intervention of 18β-GRA in GC cells,and the results were consistent with the results of miR-328-3p overexpression(P<0.05).Additional studies showed that 18β-GRA promoted autophagy flow by promoting autophagosome synthesis(P<0.001).qPCR showed that the expression of STAT3 mRNA was downregulated after drug intervention(P<0.05).Western blot analysis showed that the expression levels of STAT3 and p-STAT3 were significantly downregulated after drug intervention(P<0.05).CONCLUSION 18β-GRA promotes the synthesis of autophagosomes and inhibits GC cell proliferation by regulating the miR-328-3p/STAT3 signaling pathway.
文摘Pancreatic ductal adenocarcinoma(PDAC) remains a deadly disease with no efficacious treatment options. PDAC incidence is projected to increase, which may be caused at least partially by the obesity epidemic. Significantly enhanced efforts to prevent or intercept this cancer are clearly warranted. Oncogenic KRAS mutations are recognized initiating events in PDAC development, however, they are not entirely sufficient for the development of fully invasive PDAC.Additional genetic alterations and/or environmental, nutritional, and metabolic signals, as present in obesity, type-2 diabetes mellitus, and inflammation, are required for full PDAC formation. We hypothesize that oncogenic KRAS increases the intensity and duration of the growth-promoting signaling network.Recent exciting studies from different laboratories indicate that the activity of the transcriptional co-activators Yes-associated protein(YAP) and WW-domaincontaining transcriptional co-activator with PDZ-binding motif(TAZ) play a critical role in the promotion and maintenance of PDAC operating as key downstream target of KRAS signaling. While initially thought to be primarily an effector of the tumor-suppressive Hippo pathway, more recent studies revealed that YAP/TAZ subcellular localization and co-transcriptional activity is regulated by multiple upstream signals. Overall, YAP has emerged as a central node of transcriptional convergence in growth-promoting signaling in PDAC cells. Indeed, YAP expression is an independent unfavorable prognostic marker for overall survival of PDAC. In what follows, we will review studies implicating YAP/TAZ in pancreatic cancer development and consider different approaches to target these transcriptional regulators.
基金Supported by the National“863”Program(2006AA10A210)~~
文摘The peaT1 gene fragment was amplified from pGEM-6p-l-peaT1 by PCR, and recovered target gene was cloned into pLexA vector. After digestion and sequencing, the bait vector pLexA-peaT1 was transformed into yeast strain EGY48 [p8op-lacZ] by PEG/LiAC, and the transcriptional activity of bait vector was detected. The results showed that recombinant bait plasmid pLexA-PEMG1 was constructed, for the two bands of recombinant bait plasmid in agarose gel eleetrophoresis were expected after digesting by restriction endonuclease EcoR I and Xho I. Therefore, the recombinant bait plasmid could be used in yeast two-hybrid system to screen a cDNA library.
基金Supported by National Natural Science Foundation of China,No.30930013
文摘Signal transducer and activator of transcription 3(STAT3), a member of the STAT family, is a key regulator of many physiological and pathological processes. Significant progress has been made in understanding the transcriptional control, posttranslational modification, cellular localization and functional regulation of STAT3. STAT3 can translocate into the nucleus and bind to specific promoter sequences, thereby exerting transcriptional regulation. Recent studies have shown that STAT3 can also translocate into mitochondria, participating in aerobic respiration and apoptosis. In addition, STAT3 plays an important role in inflammation and tumorigenesis by regulating cell proliferation, differentiation and metabolism. Conditional knockout mouse models make it possible to study the physiological function of STAT3 in specific tissues and organs. This review summarizes the latest advances in the understanding of the expression, regulation and function of STAT3 in physiological and tumorigenic processes.
基金the Program of Science and Technology, Zhenjiang City, No. SH2006019
文摘AIM:To investigate the roles and mechanism of signal transducer and activator of transcription 3 (STAT3) in invasion of human colon cancer cells by RNA interference. METHODS: Small interfering RNA (siRNA) targeting Signal transducer and activator of transcription 3 (STAT3) was transfected into HT29 colon cancer cells. STAT3 protein level and DNA-binding activity of STAT3 was evaluated by western blotting and electrophoretic mobility shift assay (EMSA), respectively. We studied the anchorage-independent growth using colony formation in soft agar, and invasion using the boyden chamber model, anoikis using DNA fragmentation assay and terminal deoxynucleotidyltransferase-mediated dUTP nick-end labeling (TUNEL), respectively. Western blot assay was used to observe the protein expression of Bcl-xL and survivin in colon cancer HT29 cells. RESULTS: RNA interference (RNAi) mediated by siRNA leads to suppression of STAT3 expression in colon cancer cell lines. Suppression of STAT3 expression by siRNA could inhibit anchorage-independent growth, and invasion ability, and induces anoikis in the colon cancer cell line HT29. It has been shown that knockdown of STAT3 expression by siRNA results in a reduction in expression of Bcl-xL and survivin in HT29 cells. CONCLUSION: These results suggest that STAT3 siRNA can inhibit the invasion ability of colon cancer cells through inducing anoikis, which antiapoptotic genes survivin and Bcl-xL contribute to regulation of anoikis.These studies indicate STAT3 siRNA could be a useful therapeutic tool for the treatment of colon cancer.
基金Supported by the National Natural Science Foundation of China,No.81070319the Beijing Natural Science Foundation of China,No.7102013the Beijing Municipal Education Commission Research Program,China,No.KM201610025004
文摘BACKGROUND Study shows that signal transducer and activator of transcription 3(STAT3) can increase the Warburg effect by stimulating hexokinase 2 in breast cancer and upregulate lactate dehydrogenase A and pyruvate dehydrogenase kinase 1 in myeloma. STAT3 and pyruvate kinase M2(PKM2) can also be activated and enhance the Warburg effect in hepatocellular carcinoma. Precancerous lesions are critical to human and rodent hepatocarcinogenesis. However, the underlying molecular mechanism for the development of liver precancerous lesions remains unknown. We hypothesized that STAT3 promotes the Warburg effect possibly by upregulating p-PKM2 in liver precancerous lesions in rats.AIM To investigate the mechanism of the Warburg effect in liver precancerous lesions in rats.METHODS A model of liver precancerous lesions was established by a modified Solt-Farber method. The liver pathological changes were observed by HE staining and immunohistochemistry. The transformation of WB-F344 cells induced with Nmethyl-N'-nitro-N-nitrosoguanidine and hydrogen peroxide was evaluated by the soft agar assay and aneuploidy. The levels of glucose and lactate in the tissue and culture medium were detected with a spectrophotometer. The protein levels of glutathione S-transferase-π, proliferating cell nuclear antigen(PCNA), STAT3,and PKM2 were examined by Western blot and immunofluorescence.RESULTS We found that the Warburg effect was increased in liver precancerous lesions in rats. PKM2 and p-STAT3 were upregulated in activated oval cells in liverprecancerous lesions in rats. The Warburg effect, p-PKM2, and p-STAT3 expression were also increased in transformed WB-F344 cells. STAT3 activation promoted the clonal formation rate, aneuploidy, alpha-fetoprotein expression,PCNA expression, G1/S phase transition, the Warburg effect, PKM2 phosphorylation, and nuclear translocation in transformed WB-F344 cells.Moreover, the Warburg effect was inhibited by stattic, a specific inhibitor of STAT3, and further reduced in transformed WB-F344 cells after the intervention for PKM2.CONCLUSION The Warburg effect is initiated in liver precancerous lesions in rats. STAT3 activation promotes the Warburg effect by enhancing the phosphorylation of PKM2 in transformed WB-F344 cells.
基金supported by the National Natural Sci-ence Foundation of China (30871689)the Program for New Century Excellent Talents in University, China(NCET-07-0565)Science Foundation from the Department of Education of Liaoning Province, China(20060772)
文摘One possible mechanism suggested for somaclonal variation is the activation of transposable elements. The activation of retrotransposons by stresses and external changes is commonly observed in plants. In previous study, we isolated the reverse transcriptase (RT) gene sequences of Ty 1-copia retrotransposons from tissue culture strawberry (Fragaria x ananassa) plant, but not the transcriptionally active sequence. For further understanding the relationship between retrotransposon and somaclonal varation, in this study, we isolated the transcriptionally active RT gene sequences from strawberry plants subjected to different abiotic stresses. These retrotransposons were activated by spraying strawberry leaves with 2 mmol L^-1 salicylic acid (SA), 50 mmol L^-1 methyl jasmonate (MeJA), 50 mmol L^-1 abscisic acid (ABA), 50 mmol L^-1 2,4- dichlorophenoxyacetic acid (2,4-D) or by inducing callus growth in 2 types of MS media: first medium supplemented with 0.5 mg L^-1 6-benzylaminopurine (6-BA), 0.5 mg L^-1 gibberellic acid (GA3), 1.0 mg L^-1 thidiazuron (TDZ), and 0.1 mg L^-1 2,4-D, and the second medium supplemented with 0.5 mg L^-1 6-BA, 0.5 mg L^-1 GA3, 2.0 mg L^-1 TDZ, and 0.02 mg L^-1 indole butyric acid (1BA). Analysis of gene sequences of 17 RTs revealed that none of them contained stop codons and/or indels disrupting the reading frame. These different stress-origin transcriptionally active RTs were remarkably similar to each other- FATEXP2-8 and FATEYS9-7 showed 100% sequence identity. Analysis of pylogenetic of these transcriptionally active RTs and the RT sequences from genome showed that there were close phylogenetic relationships of most of the transcriptionally active RTs. The results of this study have contributed to the background information necessary for future studies for evaluating the relationship between retrotransposons and somaclonal variation.
基金Supported by The Science and Technology Fund of Jilin Province,No. 200505219
文摘AIM: To explore the effect of silencing of signal transducer and activator of transcription 3 (STAT3) expression by RNA interference (RNAi) on growth of human hepatocellular carcinoma (HCC) in tumorbearing nude mice in vivo.METHODS: To construct the recombinant plasmid of pSilencer 3.0-H1-STAT3-siRNA-GFP (pSHI-siRNA- STAT3) and establish the tumor-bearing nude mouse model of the HCC cell line SMMC7721, we used intratumoral injection together with electroblotting to transfect the recombinant plasmid pSHI-siRNA- STAT3 into the transplanted tumor. The weight of the nude mice and tumor volumes were recorded. STAT3 gene transcription was detected by semi-quantitative reverse transcription polymerase chain reaction (RT- PCR). Level of protein expression and location of STAT3 were determined by Western blotting and immunohistochemical staining. STAT3-related genes such as survivin, c-myc, VEGF, p53 and caspase3 mRNA and protein expression were detected in tumor tissues at the same time. The terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assay was used to detect apoptosis of tumor cells.RESULTS: The weight of the treated nude mice increased, and the tumor volume decreased markedly compared with those of the mock-treated and negative control groups (P 〈 0.01). The results of RT-PCR and Western blotting showed that mRNA and protein levels of STAT3 declined markedly in the treated group. The change in STAT3-related gene expression in tumor tissues at the mRNA and protein level also varied, the expression of survivin, VEGF and c-myc were obviously reduced, and expression of p53 and caspase3 increased (P 〈 0.01). Most of the tumor tissue ceils in the treated group developed apoptosis that was detected by TUNEL assay.CONCLUSION: Silencing of STAT3 expression by RNAi significantly inhibits expression of STAT3 mRNA and protein, and suppresses growth of human HCC in tumor-bearing nude mice. The mechanism may be related to down-regulation of survivin, VEGF and c-myc and up-regulation of p53 and caspase3 expression. Accordingly, the STAT3 gene may act as an important and effective target in gene therapy of HCC.
文摘Hepatocellular carcinoma is one of the most common cancers worldwide,and a leading cause of cancer-related death.Owing to unsatisfactory clinical outcomes under the current standard of care,there is a need to search for and identify novel and potent therapeutic targets to improve patient outcomes.Sorafenib is the first and only approved targeted therapy for the treatment of hepatocellular carcinoma.Besides functioning as a multiple tyrosine kinase,sorafenib also acts via a kinase-independent mechanism to target signal transducer and activator of transcription 3(STAT3) signaling in hepatocellular carcinoma cells.STAT3 is a key regulator of inflammation,cell survival,and tumorigenesis of liver cells,and the high percentage of hepatocellular carcinoma cells with constitutively active STAT3 justifies targeting it for the development of novel therapeutics.Sorafenib inactivates STAT3 and STAT3-related signaling by inducing a conformational change in and releasing the autoinhibition of Src homology region 2 domaincontaining phosphatase-1.This phosphatase negatively regulates STAT3 activity,which leads to the subsequent apoptosis of cancer cells.The novel anti-cancer property of sorafenib will be discussed in this review,not only adding information regarding its mechanism of action but also providing an innovative approach for the development of cancer therapeutics in the future.
基金supported by the National Natural Science Foundation of China(NSFC)(81973316,82173807)the China Postdoctoral Science Foundation(2020M681914)+1 种基金the Fund from Tianjin Municipal Health Commission(ZC200093)the Open Fund of Tianjin Central Hospital of Obstetrics and Gynecology/Tianjin Key Laboratory of human development and reproductive regulation(2021XHY01)。
文摘Psoriasis is a chronic autoimmune disease featured by patches on the skin.It is caused by malfunction of immune cells and keratinocytes with inflammation as one of its key features.Apigenin(API)is a natural flavonoid with anti-inflammatory and immunoregulatory properties.Therefore,we speculated that API can ameliorate psoriasis,and determined its effect on the development of psoriasis by using imiquimod(IMQ)-induced psoriasis mouse model.Our results showed that API attenuated IMQ-induced phenotypic changes,such as erythema,scaling and epidermal thickening,and improved splenic hyperplasia.Abnormal differentiation of immune cells was restored in API-treated mice.Mechanistically,we revealed that API is a key regulator of signal transducer activator of transcription 3(STAT3).API regulated immune responses by reducing interleukin-23(IL-23)/STAT3/IL-17A axis.Moreover,it suppressed IMQ-caused cell hyperproliferation by inactivating STAT3 through regulation of extracellular signal-regulated kinase 1/2 and nuclear factor-κB(NF-κB)pathway.Furthermore,API reduced expression of inflammatory cytokines through inactivation of NF-κB.Taken together,our study demonstrates that API can ameliorate psoriasis and may be considered as a strategy for psoriasis treatment.
基金supported by NIH R21AR57156NIH R37 CA49152+4 种基金the Rhode Island Hospital Orthopaedic Foundationgrant from the Pediatric Orthopaedic Society of North AmericaArthritis National Research Foundationrecipient of Ryan Fellowshippilot award recipient from NIGMS1P20 GM119943
文摘Chondrocytes and osteoblasts differentiate from a common mesenchymal precursor, the osteochondroprogenitor(OCP), and help build the vertebrate skeleton. The signaling pathways that control lineage commitment for OCPs are incompletely understood. We asked whether the ubiquitously expressed protein-tyrosine phosphatase SHP2(encoded by Ptpn11) affects skeletal lineage commitment by conditionally deleting Ptpn11 in mouse limb and head mesenchyme using "Cre-lox P"-mediated gene excision.SHP2-deficient mice have increased cartilage mass and deficient ossification, suggesting that SHP2-deficient OCPs become chondrocytes and not osteoblasts. Consistent with these observations, the expression of the master chondrogenic transcription factor SOX9 and its target genes Acan, Col2a1, and Col10a1 were increased in SHP2-deficient chondrocytes, as revealed by gene expression arrays, q RT-PCR, in situ hybridization, and immunostaining. Mechanistic studies demonstrate that SHP2 regulates OCP fate determination via the phosphorylation and SUMOylation of SOX9, mediated at least in part via the PKA signaling pathway. Our data indicate that SHP2 is critical for skeletal cell lineage differentiation and could thus be a pharmacologic target for bone and cartilage regeneration.
文摘Signal transducer and activator of transcription(STAT)is a unique protein family that binds to DNA,coupled with tyrosine phosphorylation signaling pathways,acting as a transcriptional regulator to mediate a variety of biological effects.Cerebral ischemia and reperfusion can activate STATs signaling pathway,but no studies have confirmed whether STAT activation can be verified by diffusion-weighted magnetic resonance imaging(DWI)in rats after cerebral ischemia/reperfusion.Here,we established a rat model of focal cerebral ischemia injury using the modified Longa method.DWI revealed hyperintensity in parts of the left hemisphere before reperfusion and a low apparent diffusion coefficient.STAT3 protein expression showed no significant change after reperfusion,but phosphorylated STAT3 expression began to increase after 30 minutes of reperfusion and peaked at 24 hours.Pearson correlation analysis showed that STAT3 activation was correlated positively with the relative apparent diffusion coefficient and negatively with the DWI abnormal signal area.These results indicate that DWI is a reliable representation of the infarct area and reflects STAT phosphorylation in rat brain following focal cerebral ischemia/reperfusion.
基金Supported by National Natural Science Foundation of ChinaNo. 39670671, No. 30471531
文摘AIM: To study the effect of Hepatitis C virus nonstructural 5A (HCV NSSA) on IFNα induced signal transducer and activator of transcription-1 (STAT1) phosphorylation and nuclear translocation.METHODS: Expression of STAT1 Tyr701 phosphorylation at different time points was confirmed by Western blot, and the time point when p-STAT1 expressed most, was taken as the IFN induction time for further studies. Immunocytochemistry was used to confirm the successful transient transfection of NS5A expression plasmid. Immunofluorescene was performed to observe if there was any difference in IFNα-induced STAT1 phosphorylation and nuclear translocation between HCV NSSA-expressed and non-HCV NSSA-expressed cells. Western blot was used to compare the phosphorylated STAT1 protein of the cells.RESULTS: Expression of HCV NS5A was found in the cytoplasm of pCNS5A-transfected Huh7 cells, but not in the PRC/ CMV transfected or non-transfected cells, STAT1 Tyr701 phosphorylation was found strongest in 30 min of IFN induction, STAT1 phosphorylation and nuclear import were much less in the presence of HCV NS5A protein in contrast to pRC/CMV-transfected and non-transfected cells under fluorescent microscopy, which was further confirmed by Western blot.CONCLUSION: HCV NSSA expression plasmid is successfully transfected into Huh7 cells and HCV NS5A protein is expressed in the cytoplasm of the cells. IFN-α is able to induce STAT1 phosphrylation and nuclear translocation, and this effect is inhibited by HCV NS5A protein, which might be another possible resistance mechanism to interferon alpha therapy.
文摘The Janus kinase and signal transducer and activator of transcription (JAK/STAT) signal transduction pathway is involved in sepsis-induced functional damage to the heart, liver, kidney, and other organs. However, the cellular and molecular mechanisms underlying sepsis-induced brain damage remain elusive. In the present study, we found severe loss of neurons in the hippocampal CA1 region in rats with sepsis-induced brain damage following intraperitoneal injection of endotoxin, The expression of toll-like receptor 4, tumor necrosis factor a, and interleukin-6 was significantly increased in brain tissues following lipopolysaccharide exposure. AG490 (JAK2 antagonist) and rapamycin (STAT3 antagonist) significantly reduced neuronal loss and suppressed the increased expression of toll-like receptor 4, tumor necrosis factor a, and interleukin-6 in the hippocampal CA1 region in sepsis-induced brain damaged rats. Overall, these data suggest that blockade of the JAK/STAT signal transduction pathway is neuroprotective in sepsis-induced brain damage via the inhibition of toll-like receptor 4, tumor necrosis factor a, and interleukin-6 exoression.
基金supported by the National Natural Science Foundation of China (# 81502345 to Qian Li and #81470717 to Yanheng Zhou)the International Science & Technology Cooperation Program of China (#2015DFB30040 to Yanheng Zhou)
文摘The interplay between mechanoresponses and a broad range of fundamental biological processes, such as cell cycle progression,growth and differentiation, has been extensively investigated. However, metabolic regulation in mechanobiology remains largely unexplored. Here, we identified glucose transporter 1(GLUT1)—the primary glucose transporter in various cells—as a novel mechanosensitive gene in orthodontic tooth movement(OTM). Using an in vivo rat OTM model, we demonstrated the specific induction of Glut1 proteins on the compressive side of a physically strained periodontal ligament. This transcriptional activation could be recapitulated in in vitro cultured human periodontal ligament cells(PDLCs), showing a time-and dose-dependent mechanoresponse. Importantly, application of GLUT1 specific inhibitor WZB117 greatly suppressed the efficiency of orthodontic tooth movement in a mouse OTM model, and this reduction was associated with a decline in osteoclastic activities. A mechanistic study suggested that GLUT1 inhibition affected the receptor activator for nuclear factor-κ B Ligand(RANKL)/osteoprotegerin(OPG)system by impairing compressive force-mediated RANKL upregulation. Consistently, pretreatment of PDLCs with WZB117 severely impeded the osteoclastic differentiation of co-cultured RAW264.7 cells. Further biochemical analysis indicated mutual regulation between GLUT1 and the MEK/ERK cascade to relay potential communication between glucose uptake and mechanical stress response. Together, these cross-species experiments revealed the transcriptional activation of GLUT1 as a novel and conserved linkage between metabolism and bone remodelling.
基金supported by National Key Research and Development Program of China(2022YFD1200202)State Key Laboratory of North China Crop Improvement and Regulation(NCCIR2022ZZ-7)Graduate Student Innovation Ability Training Funding Project of Hebei Province(CXZZBS2023073)。
文摘SNF1-related protein kinase 2(SnRK2)family members are essential components of the plant abscisic acid(ABA)signaling pathway initiated by osmotic stress and triggering a drought stress response.This study characterized the molecular properties of TaSnRK2.4 and its function in mediating adaptation to drought in Triticum aestivum.Transcripts of TaSnRK2.4 were upregulated upon drought and ABA signaling and associated with drought-and ABA-responsive cis-elements ABRE and DRE,and MYB and MYC binding sites in the promoter as indicated by reporter GUS protein staining and activity driven by truncations of the promoter.Yeast two-hybrid,BiFC,and Co-IP assays indicated that TaSnRK2.4 protein interacts with TaPP2C01 and an ABF transcription factor(TF)TaABF2.The results suggested that TaSnRK2.4 forms a functional TaPP2C01-TaSnRK2.4-TaABF2 module with its upstream and downstream partners.Transgene analysis revealed that TaSnRK2.4 and TaABF2 positively regulate drought tolerance whereas TaPP2C01 acts negatively by modulating stomatal movement,osmotic adjustment,reactive oxygen species(ROS)homeostasis,and root morphology.Expression analysis,yeast one-hybrid,and transcriptional activation assays indicated that several osmotic stress-responsive genes,including TaSLAC1-4,TaP5CS3,TaSOD5,TaCAT1,and TaPIN4,are regulated by TaABF2.Transgene analysis verified their functions in positively regulating stomatal movement(TaSLAC1-4),proline accumulation(TaP5CS3),SOD activity(TaSOD5),CAT activity(TaCAT1),and root morphology(TaPIN4).There were high correlations between plant biomass and yield with module transcripts in a wheat variety panel cultivated under drought conditions in the field.Our findings provide insights into understanding plant drought response underlying the SnRK2 signaling pathway in common wheat.
基金supported by the National Key Research and Development Program of China(SQ2019YFC170218).
文摘Objective:To investigate the molecular mechanism and identify potential drugs for subthreshold depression(SD),and elucidate the detalied mechanism of Danzhi Xiaoyao powder(DZXY)in SD.Methods:Using RNA-sequencing,we identified differentially expressed genes(DEGs)in leukocytes of SD compared to healthy controls,deciphered their functions and pathways,and identified the hub genes of SD.We also assessed changes in leukocyte transcription factor activity in patients with SD using the TELis platform.The Connectivity Map database was retrieved to screen candidate drugs for SD.Based on network pharmacology,we elucidated the"multi-component,multi-target,and multi-pathway"mechanism of DZXY in the treatment of SD.Results:We identified 1080 DEGs(padj<0.05 and|log2(fold change)l≥1&protein coding)in the leukocytes of patients with SD.These DEGs,including hub genes,were primarily involved in immune and inflammatory response-related processes.Transcription factor activity analysis revealed similarities between the leukocyte transcriptome profile in SD and the conserved transcriptional response to adversities in immune cells.Connectivity Map analysis identified 28 potential drugs for SD treatment,particularly SB-202190 and TWS-119.Constructing the"Direct Compounds-Direct Targets-Pathways"network for DZXY and SD revealed the curative mechanisms of DZXY in SD,primarily including inflammatory response,lipid metabolism,immune response,and other processes.Conclusion:These results provide new insights into the characteristics and functional changes of leukocytes in SD,partially illustrate the pathogenesis of SD,and suggest potential drugs for SD.The curative mechanisms of DZXY in SD are also partially elucidated.
基金This work was supported by a grant from the National Natural Science Foundation of China (No. 39600006).
文摘OBJECTIVE: To explore the feasibility of cloning of the hepatocyte receptor interacting with the Pre Slprotein of HBV by two-hybrid system.METHODS: Yeast expression plasmids encoding fusion proteins of full length or portions of Pre Sl ofHBV and DNA binding domain of yeast protein GAL4 were constructed and used to transform yeastreporter strain SFY526. Reporter gene product β-galactosidase activity was assayed as a measure oftranscriptional activation in yeast, Mammalian expression plasmid encoding fusion proteins of full lengthPre Sl and DNA binding domain of GAL4 was constructed and used to cotransfect hepatoma cell lineHuh-7 together with CAT reporter plasmid. Cell extracts were assayed for CAT activity by thin-layerchromatography.RESULTS: The fusion proteins of full length Pre Sl protein and GAL4 DNA binding domain presentedtranscriptional activation function in yeast. The transcription activating sequence was localized to the 21 to47 amino acids of Pre Sl protein. Fusion proteins of full length Pre Sl and GAL4 DNA binding domaindid not show transcriptional activation function in mammalian cells.CONCLUSIONS: The transcription activating sequence of HBV Pre Sl protein in yeast overlaps thehepatocyte receptor binding site. The transcriptional activation function of HBV Pre Sl protein in yeastmay prevent researchers from using yeast two-hybrid system to clone HBV receptor interacting with Pre Slprotein. However, the Pre Sl protein does not show transcriptional activation function in mammaliancells. Mammalian two-hybrid system may be a practical method to clone the HBV hepatocyte receptorinteracting with Pre Sl protein.