MicroRNA-760 acts as a tumor suppressor in gastric cancer development via inhibiting G-protein-coupled receptor kinase interacting protein-1 transcription

BACKGROUND Gastric cancer(GC)has become a serious threat to people's health.Accumulative evidence reveals that dysregulation of numerous microRNAs(miRNAs)has been found during malignant formation.So far,the role of microRNA-760(miR-760)in the development of GC is largely unknown.AIM To measure the expression level of miR-760 in GC and investigate its role in gastric tumorigenesis.METHODS Real-time quantitative polymerase chain reaction and Western blot analysis were used to measure the expression of miR-760 and G-protein-coupled receptor kinase interacting protein-1(GIT1).Cell growth was detected by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide(MTT)and cell colony formation assays.Apoptosis was assessed by flow cytometric analysis.The relationship between miR-760 and GIT1 was verified by luciferase reporter assay.RESULTS The results showed that the expression of miR-760 was decreased in GC and associated with poor clinical outcomes in GC patients.Furthermore,miR-760 restrained cell proliferation and cell colony formation and induced apoptosis in GC cells.In addition,miR-760 directly targeted GIT1 and negatively regulated its expression in GC.GIT1 was upregulated in GC and predicted a worse prognosis in GC patients.We also found that upregulation of GIT1 weakened the inhibitory CONCLUSION In conclusion,miR-760 targets GIT1 to inhibit cell growth and promote apoptosis in GC cells.Our data demonstrate that miR-760 may be a potential target for the treatment of GC.

Specific effects of c-Jun NH2-terminal kinaseinteracting protein 1 in neuronal axons

c-Jun NH2-terminal kinase（JNK）-interacting protein 3 plays an important role in brain-derived neurotrophic factor/tropomyosin-related kinase B（Trk B） anterograde axonal transport. It remains unclear whether JNK-interacting protein 1 mediates similar effects, or whether JNK-interacting protein 1 affects the regulation of Trk B anterograde axonal transport. In this study, we isolated rat embryonic hippocampus and cultured hippocampal neurons in vitro. Coimmunoprecipitation results demonstrated that JNK-interacting protein 1 formed Trk B complexes in vitro and in vivo. Immunocytochemistry results showed that when JNK-interacting protein 1 was highly expressed, the distribution of Trk B gradually increased in axon terminals. However, the distribution of Trk B reduced in axon terminals after knocking out JNK-interacting protein 1. In addition, there were differences in distribution of Trk B after JNK-interacting protein 1 was knocked out compared with not. However, knockout of JNK-interacting protein 1 did not affect the distribution of Trk B in dendrites. These findings confirm that JNK-interacting protein 1 can interact with Trk B in neuronal cells, and can regulate the transport of Trk B in axons, but not in dendrites.

Diabetes and high-glucose could upregulate the expression of receptor for activated C kinase 1 in retina

BACKGROUND Diabetic retinopathy(DR)is a major ocular complication of diabetes mellitus,leading to visual impairment.Retinal pigment epithelium(RPE)injury is a key component of the outer blood retinal barrier,and its damage is an important indicator of DR.Receptor for activated C kinase 1(RACK1)activates protein kinase C-ε(PKC-ε)to promote the generation of reactive oxygen species(ROS)in RPE cells,leading to apoptosis.Therefore,we hypothesize that the activation of RACK1 under hypoxic/high-glucose conditions may promote RPE cell apoptosis by modulating PKC-ε/ROS,thereby disrupting the barrier effect of the outer blood retinal barrier and contributing to the progression of DR.AIM To investigate the role and associated underlying mechanisms of RACK1 in the development of early DR.METHODS In this study,Sprague-Dawley rats and adult RPE cell line-19(ARPE-19)cells were used as in vivo and in vitro models,respectively,to explore the role of RACK1 in mediating PKC-εin early DR.Furthermore,the impact of RACK1 on apoptosis and barrier function of RPE cells was also investigated in the former model.RESULTS Streptozotocin-induced diabetic rats showed increased apoptosis and upregulated expression of RACK1 and PKC-εproteins in RPE cells following a prolonged modeling.Similarly,ARPE-19 cells exposed to high glucose and hypoxia displayed elevated mRNA and protein levels of RACK1 and PKC-ε,accompanied by an increases in ROS production,apoptosis rate,and monolayer permeability.However,silencing RACK1 significantly downregulated the expression of PKC-εand ROS,reduced cell apoptosis and permeability,and protected barrier function.CONCLUSION RACK1 plays a significant role in the development of early DR and might serve as a potential therapeutic target for DR by regulating RPE apoptosis and barrier function.

Fungus induces the release of IL- 8 in human corneal epithelial cells, via Dectin-1-mediated protein kinase C pathways

AIM: To identify whether Aspergillus fumigatus(A.fumigatus) hyphae antigens induced the release of interleukin-8(IL-8) in anti-fungal innate immunity of cultured human corneal epithelial cells(HCECs) and determine the involvement of intracellular signalling pathways. METHODS: HCECs were treated with A. fumigatus hyphae antigens with different concentrations and time.The cytoplasmic calcium of HCECs were assessed by fluorescence imaging. Western blot was used to detect the expression of Ca2 +-dependent protein kinase C(PKC). The IL-8 levels were determined by specific human IL-8 enzyme-linked immunosorbent assay(ELISA) and reverse transcriptase polymerase chain reaction(RT-PCR). Using a series of pharmacological inhibitors, we examined the upstream signalling pathway responsible for IL-8 expression in response to A.fumigatus hyphae antigens. RESULTS: Cells exposed to A. fumigatus hyphae antigens showed higher level of IL-8 m RNA expression and protein production. We demonstrated here that stimulation of HCECs with A. fumigatus hyphae triggers an intracellular Ca2 +flux and results in the activation of Ca2 +-dependent PKC(α, βⅠ and βⅡ) which can be attenuated by pre-treatment of cells with laminarin,suggesting that Dectin-1 signals pathway induced cytoplasmic calcium and influence the activation of PKC in HCECs. Inhibitors of Ca2 +-dependent PKC(Ro-31-8220 and Go6976) significantly abolished hyphae-induced expression of IL-8.CONCLUSION: Our findings suggest that A. fumigatushyphae-induced IL-8 expression was regulated by the activation of Dectin-1-mediated Ca2 +-dependent PKC in HCECs.

Role of Activator Protein-1 in the Transcription of Interleukin-5 Gene Regulated by Protein Kinase C Signal in Asthmatic Human TLymphocytes

Summary: In order to explore the role of activator protein-1 (AP-1) in the transcription of interleukin-5 (IL-5) gene regulated by protein kinase C (PKC) signal in peripheral blood T lymphocytes from asthmatic patient, T lymphocytes were isolated and purified from peripheral blood of each asthmatic patient. The T lymphocytes were randomly divided into 4 groups: group A (blank control), group B (treated with PKC agonist phorbol 12-myristate 13-acetate (PMA)), Group C (treated with PMA and AP-1 cis-element decoy oligodeoxynucleotides (decoy ODNs)), and group D (treated with PMA and AP-1 mutant decoy ODNs). The ODNs were transfected into the T cells of group C and D by cation liposome respectively. Reverse transcription-polymerase chain reaction (RT-PCR) was employed to assess IL-5 mRNA expression, and electrophoretic mobility shift assays (EMSA) for the activation of AP-1. The results showed that the activation of AP-1 (88 003.58±1 626.57) and the expression of IL-5 mRNA (0.8300±0.0294) in T lymphocytes stimulated with PMA were significantly higher than these in blank control (20 888.47±1103.56 and 0.3050±0.0208, respectively, P< 0.01), while the indexes (23 219.83±1 024.86 and 0.3425±0.0171 respectively) of T lymphocytes stimulated with PMA and AP-1 decoy ODNs were significantly inhibited, as compared with group B (P< 0.01). The indexes (87 107.41±1 342.92 and 0.8225±0.0222, respectively) in T lymphocytes stimulated with PMA and AP-1 mutant decoy ODNs did not exhibit significant changes, as compared with group B (P>0.05). The significant positive correlation was found between the activation of AP-1 and the expression of IL-5 mRNA (P< 0.01). It was concluded that AP-1 might participate in the signal transduction of PKC-triggered transcription of IL-5 gene in asthmatic T lymphocytes. This suggests the activation of PKC/AP-1 signal transduction cascade of T lymphocytes may play an important role in the pathogenesis of asthma.

All-trans Retinoic Acid Diminishes Collagen Production in a Hepatic Stellate Cell Line via Suppression of Active Protein-1 and c-Jun N-terminal Kinase Signal

Following acute and chronic liver injury,hepatic stellate cells (HSCs) become activated to undergo a phenotypic transformation into myofibroblast-like cells and lose their retinol content,but the mechanisms of retinoid loss and its potential roles in HSCs activation and liver fibrosis are not understood.The influence of retinoids on HSCs and hepatic fibrosis remains controversial.The purpose of this study was to evaluate the effects of all-trans retinoid acid (ATRA) on cell proliferation,mRNA expression of collagen genes [procollagen α1 (Ⅰ),procollagen α1 (Ⅲ)],profibrogenic genes (TGF-β 1,CTGF,MMP-2,TIMP-1,TIMP-2,PAI-1),fibrolytic genes (MMP-3,MMP-13) and the upstream element (JNK and AP-1) in the rat hepatic stellate cell line (CFSC-2G).Cell proliferation was evaluated by measuring BrdU incorporation.The mRNA expression levels of collagen genes [procollagen α1 (Ⅰ),procollagen α1 (Ⅲ)],profibrogenic genes (TGF-β 1,CTGF,MMP-2,TIMP-1,TIMP-2,PAI-1),and fibrolytic genes (MMP-3,MMP-13) were quantitatively detected by using real-time PCR.The mRNA expression of JNK and AP-1 was quantified by RT-PCR.The results showed that ATRA inhibited HSCs proliferation and diminished the mRNA expression of collagen genes [procollagen α1 (Ⅰ),procollagen α1 (Ⅲ)] and profibrogenic genes (TGF-β 1,CTGF,MMP-2,TIMP-1,TIMP-2,PAI-1),and significantly stimulated the mRNA expression of MMP-3 and MMP-13 in HSCs by suppressing the mRNA expression of JNK and AP-1.These findings suggested that ATRA could inhibit proliferation and collagen production of HSCs via the suppression of active protein-1 and c-Jun N-terminal kinase signal,then decrease the mRNAs expression of profibrogenic genes (TGF-β 1,CTGF,MMP-2,TIMP-1,TIMP-2,PAI-1),and significantly induce the mRNA expression of MMP-3 and MMP-13.

Mitogen-activated protein kinase phosphatase 1 protects PC12 cells from amyloid beta-induced neurotoxicity

The mitogen-activated protein kinase（MAPK） signaling pathway plays an important role in the regulation of cell growth, proliferation, differentiation, transformation and death. Mitogen-activated protein kinase phosphatase 1（MKP1） has an inhibitory effect on the p38 MAPK and JNK pathways, but it is unknown whether it plays a role in Aβ-induced oxidative stress and neuronal inflammation. In this study, PC12 cells were infected with MKP1 sh RNA, MKP1 lentivirus or control lentivirus for 12 hours, and then treated with 0.1, 1, 10 or 100 μM amyloid beta 42（Aβ42）. The cell survival rate was measured using the cell counting kit-8 assay. MKP1, tumor necrosis factor-alpha（TNF-α） and interleukin-1β（IL-1β） m RNA expression levels were analyzed using quantitative real time-polymerase chain reaction. MKP1 and phospho-c-Jun N-terminal kinase（JNK） expression levels were assessed using western blot assay. Reactive oxygen species（ROS） levels were detected using 2′,7′-dichlorofluorescein diacetate. Mitochondrial membrane potential was measured using flow cytometry. Superoxide dismutase activity and malondialdehyde levels were evaluated using the colorimetric method. Lactate dehydrogenase activity was measured using a microplate reader. Caspase-3 expression levels were assessed by enzyme-linked immunosorbent assay. Apoptosis was evaluated using the terminal deoxynucleotidyl transferase d UTP nick end labeling method. MKP1 overexpression inhibited Aβ-induced JNK phosphorylation and the increase in ROS levels. It also suppressed the Aβ-induced increase in TNF-α and IL-1β levels as well as apoptosis in PC12 cells. In contrast, MKP1 knockdown by RNA interference aggravated Aβ-induced oxidative stress, inflammation and cell damage in PC12 cells. Furthermore, the JNK-specific inhibitor SP600125 abolished this effect of MKP1 knockdown on Aβ-induced neurotoxicity. Collectively, these results show that MKP1 mitigates Aβ-induced apoptosis, oxidative stress and neuroinflammation by inhibiting the JNK signaling pathway, thereby playing a neuroprotective role.

Evidence, hypotheses and significance of MAP kinase TNNI3K interacting with its partners

TNNI3K is a cardiac-specific and cardiac troponin I(cT n I)-interacting MAP kinase, known to play important roles in promoting cardiac differentiation, maintenance of beating rhythm and contractual force. The molecular structure of TNNI3 K contains three kinds of domain: a seven or ten NH2-terminal ankyrin repeat domain followed by a protein kinase domain and a COOH-terminal serine-rich domain. There are many binding sites in the structure of TNNI3 K for binding to ATP, magnesium, nucleotide, protein kinase C, antioxidant protein 1(AOP-1) and cT n I, indicating TNNI3 K has many interacting partners. This review summarizes the evidence, hypothesis and significance of TNNI3 K interacting with TNNI3 and its other putative interaction partners. From the literature, the interaction partners of TNNI3 K are divided into 2 types following their phenotypic pattern of functions, positive interaction(to increase the cardiac performance) or negative interaction(to suppress the cardiac performance). Following their binding sites, it also can be divided into other 2 types: binding to C-terminal domain(e.g., cT n I) or binding to both ankyrin repeat domain and C-terminal domains(AOP-1).To date, a well understood partner of TNNI3 K is cT nI, from the molecular structure, physiological function, mechanisms and its significance in some physiological and pathophysiological conditions. There are many reasons to believe that, with more understanding on the TNNI3 K interacting with its partners, we can understand more roles of TNNI3 K in some cardiac diseases.

Sphingosine kinase 1 dependent protein kinase C-δ activation plays an important role in acute liver failure in mice

AIM: To investigate the role of protein kinase C(PKC)-δ activation in the pathogenesis of acute liver failure(ALF) in a well-characterized mouse model of D-galactosamine(D-Gal N)/lipopolysaccharide(LPS)-induced ALF.METHODS: BALB/c mice were randomly assigned to five groups, and ALF was induced in mice by intraperitoneal injection of D-Ga IN(600 mg/kg) and LPS(10 μg/kg). Kaplan-Meier method was used for survival analysis. Serum alanine aminotransferase(ALT) and aspartate aminotransferase(AST) levels at different time points within one week were determined using a multiparameteric analyzer. Serum levels of high-mobility group box 1(HMGB1), tumor necrosis factor(TNF)-α, interleukin(IL)-1β, IL-6, and IL-10 as well as nuclear factor(NF)-κB activity were determined by enzyme-linked immunosorbent assay. Hepatic morphological changes at 36 h after ALF induction were assessed by hematoxylin and eosin staining. Expression of PKC-δ in liver tissue and peripheral blood mononuclear cells(PBMCs) was analyzed by Western blot.RESULTS: The expression and activation of PKC-δ were up-regulated in liver tissue and PBMCs of mice with D-Gal N/LPS-induced ALF. Inhibition of PKC-δ activation with rottlerin significantly increased the survival rates and decreased serum ALT/AST levels at 6, 12 and 24 h compared with the control group(P < 0.001). Rottlerin treatment also significantly decreased serum levels of HMGB1 at 6, 12, and 24 h, TNF-α, IL-6 and IL-1 β at 12 h compared with the control group(P < 0.01). The inflammatory cell infiltration and necrosis in liver tissue were also decreased in the rottlerin treatment group. Furthermore, sphingosine kinase 1(Sph K1) dependent PKC-δ activation played an important role in promoting NF-κB activation and inflammatory cytokine production in ALF.CONCLUSION: Sph K1 dependent PKC-δ activation plays an important role in promoting NF-κB activation and inflammatory response in ALF, and inhibition of PKC-δ activation might be a potential therapeutic strategy for this disease.

Correlation between receptor-interacting protein 140 expression and directed differentiation of human embryonic stem cells into neural stem cells

Overexpression of receptor-interacting protein 140（RIP140） promotes neuronal differentiation of N2 a cells via extracellular regulated kinase 1/2（ERK1/2） signaling.However,involvement of RIP140 in human neural differentiation remains unclear.We found both RIP140 and ERK1/2 expression increased during neural differentiation of H1 human embryonic stem cells.Moreover,RIP140 negatively correlated with stem cell markers Oct4 and Sox2 during early stages of neural differentiation,and positively correlated with the neural stem cell marker Nestin during later stages.Thus,ERK1/2 signaling may provide the molecular mechanism by which RIP140 takes part in neural differentiation to eventually affect the number of neurons produced.

Electroacupuncture preconditioning protects against focal cerebral ischemia/reperfusion injury via suppression of dynamin-related protein 1

Electroacupuncture preconditioning at acupoint Baihui （GV20） can reduce focal cerebral ischemia/reperfusion injury. However, the precise protective mechanism remains unknown. Mitochondrial fission mediated by dynamin-related protein 1 （Drp1） can trigger neuronal apoptosis following cerebral ischemia/reperfusion injury. Herein, we examined the hypothesis that electroacupuncture pretreatment can regulate Drp1, and thus inhibit mitochondrial fission to provide cerebral protection. Rat models of focal cerebral ischemia/reperfusion injury were established by middle cerebral artery occlusion at 24 hours after 5 consecutive days of preconditioning with electroacupuncture at GV20 （depth 2 mm, intensity 1 mA, frequency 2/15 Hz, for 30 minutes, once a day）. Neurological function was assessed using the Longa neurological deficit score. Pathological changes in the ischemic penumbra on the injury side were assessed by hematoxylin-eosin staining. Cellular apoptosis in the ischemic penumbra on the injury side was assessed by terminal deoxyribonucleotidyl transferase-mediated dUTP-digoxigenin nick end labeling staining. Mitochondrial ultrastructure in the ischemic penumbra on the injury side was assessed by transmission electron microscopy. Drp1 and cytochrome c expression in the ischemic penumbra on the injury side were assessed by western blot assay. Results showed that electroacupuncture preconditioning decreased expression of total and mitochondrial Drp1, decreased expression of total and cytosolic cytochrome c, maintained mitochondrial morphology and reduced the proportion of apoptotic cells in the ischemic penumbra on the injury side, with associated improvements in neurological function. These data suggest that electroacupuncture preconditioning-induced neuronal protection involves inhibition of the expression and translocation of Drp1.

妊娠期高血压疾病患者血清hs-CRP、sFlt-1水平变化及与妊娠结局的相关性

目的:探讨妊娠期高血压疾病(HDP)患者血清可溶性血管内皮生长因子受体-1(sFlt-1)、超敏C反应蛋白(hs-CRP)水平变化及与妊娠结局的相关性。方法:收集2022年1月—2023年2月于赣州市妇幼保健院接受治疗的HDP患者108例作为病例组,并进行回顾性分析。根据病情严重程度将病例组患者分为妊娠期高血压组(43例)、子痫前期组(35例)、子痫组(30例),并选取同期正常妊娠的妇女82例作为对照组。分析所有研究对象中血清hs-CRP、sFlt-1水平变化情况。结果:病例组血清hs-CRP、sFlt-1水平均明显高于对照组(P<0.05)。妊娠期高血压组、子痫前期组、子痫组患者血清hs-CRP、sFlt-1水平比较差异均有统计学意义(P<0.05),且血清hs-CRP、sFlt-1水平随病情严重程度的加重而升高(P<0.05)。不良妊娠结局组患者血清hs-CRP、sFlt-1水平均高于妊娠结局良好组(P<0.05)。血清hs-CRP、s Flt-1水平反映HDP患者妊娠结局的AUC分别为0.758、0.763。相关性分析显示,hs-CRP、sFlt-1之间呈正相关(r=0.743,P<0.001)。结论:HDP患者血清中hs-CRP、sFlt-1水平均升高,且随疾病严重程度的加重而增加,并与妊娠结局有一定的相关性。

Neuronal effects of SP600125 pretreatment in a rat model of cerebral ischemia/reperfusion injury Inhibited down-regulation of DNA repair protein

BACKGROUND： Recent studies have shown that the selective inhibitor of c-Jun N-terminal kinases （JNKs） signaling pathway, SP600125, exhibits neuronal protective effects in a rat model of brain ischemia/reperfusion. OBJECTIVE： To determine the mechanisms of neuroprotective effects of SP600125 in a rat model of brain ischemia/reperfusion, and determine the role of the JNK signaling pathway in SP600125-induced effects. DESIGN, TIME AND SETTING： A randomized, controlled, animal experiment was performed at the Animal Experiment Center, Medical School of Xi＇an Jiaotong University from June 2007 to September 2008. MATERIALS： SP600125 was provided by Biosource, USA; rabbit anti-phospho-JNK （Thr183/Tyr185） polyclonal antibody from Cell Signaling Technology, USA; rabbit anti-X-ray repair cross-complementing protein 1 （XRCC1） and anti-Ku70 polyclonal antibodies from Santa Cruz Biotechnology, USA; and TUNEL kit from Beijing Huamei Biology, China. METHODS： A total of 108 male, 4-month-old, Sprague Dawley rats were randomly assigned to three groups, with 36 rats per group. The sham operation group and ischemia/reperfusion group （I/R group） were intracerebroventricularly injected with 10 μL 1% DMSO. The SP600125-treated group （pre-SP group） was given 10 μL SP600125 （3 μg/μL）. Thirty minutes later, brain ischemia was induced in the I/R and pre-SP groups using the four-vessel occlusion method. Specifically, whole brain ischemia was induced for 6 minutes, and the clips were released to restore carotid artery blood flow. Rats from each group were observed at 2, 6, 12, 24, 48, and 72 hours, with 6 rats for each time point. The sham operation group was treated with the same surgical exposure procedures, with exception of occlusion of the carotid artery. MAIN OUTCOME MEASURES： Hematoxylin-eosin staining was used to observe neuronal survival in the hippocampal CA1 region, TUNEL was used to detect apoptosis in the hippocampal CA1 region, and immunohistochemistry was used to detect expression of phospho-JNK, XRCC1, and Ku70. RESULTS： Following brain ischemia/reperfusion, neuronal survival significantly decreased, and the number of apoptotic cells significantly increased （P 〈 0.01）. Compared with the I/R group, neuronal survival significantly increased in the pre-SP group, and the number of apoptotic cells significantly decreased （P 〈 0.01）. Expression of phospho-JNK increased, and XRCC1 and Ku70 significantly decreased （P 〈 0.05） following ischemia/reperfusion. Compared with the I/R group, expression of phospho-JNK decreased, and XRCC1 and Ku70 significantly increased in the pre-SP group （P 〈 0.05）. Correlation analysis revealed an inverse correlation between phospho-JNK gray value and XRCC1 and Ku70 gray values in the hippocampal CA1 region （r = -0.983, -0.953, P 〈 0.01）. CONCLUSION： SP600125 treatment decreased apoptosis induced by global brain ischemia/reperfusion in the rat hippocampal CA1 region. Results suggested that the neuroprotective effects were due to inhibited phosphorylation of JNK and reduced down-regulation of XRCC1 and Ku70.

Distinct protein kinase C isozymes mediates inhibitory effects of different G-protein coupled receptors on cardiac rapidly activating delayed rectifier K ~ current

Aim Evidence has shown that stimulation of alA-adrenorecetors receptor （alA-AR） or angiotensin II type 1 receptor （AT1R） acutely down-regulates the rapid component of the delayed rectifier K ＋ current （IKr） via protein kinase C （PKC）. This study was designed to investigate which PKC isozymes mediate down-regulations of IKr by alA-AR and AT1R. Method The whole-cell patch-clamp technique was used to record IKr in native cardio- myocytes and in human embryonic kidney （HEK） 293 cells co-transfected with human ether-a-go-go related gene （hERG） encoding α-subunit of IKr and human alA-AR or AT1R gene. Result In isolated guinea-pig ventricular cardiomyocytes the inhibitory action of Ang II on IKr was little affected by Go6976 （selectively inhibiting PKCα, β and γ） and Go6983 （selectively inhibiting PKCα, β, γ , δ, and ζ）, but was significantly antagonized by an inter- nal dialysis with PKCe-selective inhibitory peptide εV1 -2. In contrast, the inhibitory action of alA-AR agonist A61603 on IKr was remarkably attenuated by Go6976 or Go6983, but not affected by peptide εV1 -2. Moreover, specific PKC-selective inhibitory peptide antagonized the effect of A61603. The results suggested that PKCe and PKCα isoform respectively mediated the inhibitory effect of AT1R and a1A-AR. In heterologous expression system, both PKCα and e-selective activator peptides down regulated hERG current with different manner. PKCα activator peptide shifted the activation curve of the channel to the right, but PKCe-selective activator peptide did not. Simi- larly, A61603 shifted the activation curve to the right, whereas Ang Ⅱ had no effect. In addition, both A61603 and PKCα activator peptide showed inhibitory action on bERG A PKC current （an bERG mutant in which 17 of the 18 ROSITE-predicted PKC acceptor serines/threonines were changed to alanine） with a similar potency to wild type bERG current. But, both Ang Ⅱ and PKCe-selective activator peptide exhibited no effects on bERG △ PKC cur- rent. The results indicated that PKCα and PKCe isoforms down-regulated bERG current through different mecha- nism. Conclusion PKCα and PKCe isoform respectively mediates the inhibition on IKr by stimulation of AT1R and alA-AR via different molecular mechanism.

血管紧张素-(1-7)对大鼠血管平滑肌细胞PKC和ERK1/2的抑制作用

采用Westernblot、氚 胸腺嘧啶 ( 3H TdR)和氚 亮氨酸 ( 3H Leu )掺入等技术和方法 ,用血管紧张素Ⅱ(AngⅡ )和血管紧张素 ( 1 7) [Ang ( 1 7) ]刺激大鼠血管平滑肌细胞 (VSMCs) ,观察和分析Ang ( 1 7)对VSMCs增殖及蛋白激酶C (PKC)和胞外调节蛋白激酶 (ERK)表达的影响。Ang ( 1 7)能明显抑制基础和AngⅡ刺激下的VSMCsPKC ζ和ERK1/ 2蛋白表达 (P <0 0 1或P <0 0 5 ) ,减少3H TdR和3H Leu掺入量 (P <0 0 1或P <0 0 5 )。结果提示 ,Ang ( 1 7)对VSMCs增殖有抑制作用 ,这可能与影响PKC ζ和ERK1/ 2蛋白表达有关。

麦冬皂苷D’通过RIP1/MLKL诱导前列腺癌PC3细胞程序性坏死

目的研究天然皂苷类化合物麦冬皂苷D’(Ophiopogonin D’,OPD’)对雄激素非依赖的前列腺癌PC3细胞的抗肿瘤效应及其机制。方法不同浓度的OPD’处理前列腺癌PC3细胞后,MTT实验检测细胞生长能力,流式细胞术检测Annexin V-Fitc和PI双染,Western blot检测程序性坏死相关蛋白——受体相互作用蛋白1(receptor interacting protein-1,RIP1)、混合谱系激酶结构区域样蛋白(mixed lineage kinase domain-like,MLKL)的表达,结晶紫染色、透射电镜观察细胞形态学的改变。结果OPD’抑制PC3细胞生长活性,24 h IC50值为(6.25±0.31)μmol/L。5μmol/L OPD’处理24 h诱导PC3细胞凋亡和坏死,5μmol/L OPD’处理6 h PC3细胞在晚期凋亡/坏死象限呈明显的时间依赖关系(r=0.728,P<0.001)。OPD’诱导PC3细胞Caspase非依赖性死亡,且其死亡能被程序性坏死(necroptosis)特异性抑制剂necrostatin-1(Nec-1)所抑制(P=0.047),表明OPD’诱导PC3细胞程序性坏死。OPD’下调Cleaved-RIP1、上调RIP1的表达;上调p-MLKL四聚体的表达,并呈明显的时间依赖关系(r=0.907,P=0.005)。形态学上OPD’诱导PC3细胞坏死样改变。结论 OPD’抑制前列腺癌细胞生长具有明显的抗肿瘤效应,而诱导其通过RIP1/MLKL通路发生程序性坏死可能是其发挥抗肿瘤效应的机制之一。

c-fos基因在内皮素-1促肺泡Ⅱ型细胞表面活性物质合成中的作用

应用反义技术探讨ｃｆｏｓ基因在ＥＴ１调控肺泡Ⅱ型细胞（ＡＴⅡ）表面活性物质（ＰＳ）合成的胞内信号转导中的作用。结果显示：（１）内皮素１（ＥＴ１）可提高ＡＴⅡ细胞的３Ｈ胆碱掺入量。（２）蛋白激酶Ｃ（ＰＫＣ）激活剂ＰＭＡ可使ＡＴⅡ细胞的３Ｈ胆碱掺入量增加，ＰＫＣ抑制剂Ｈ７可抑制ＥＴ１的促ＰＳ合成效应。（３）ＥＴ１和ＰＭＡ可显著提高Ｆｏｓ蛋白表达量。Ｈ７和ｃｆｏｓ反义寡核苷酸（ＯＤＮ）预处理可抑制ＥＴ１促Ｆｏｓ蛋白表达和促３Ｈ胆碱掺入效应。（４）ＥＴ１、正义及反义ＯＤＮ对ＡＴⅡ细胞乳酸脱氢酶（ＬＤＨ）释放量均无显著影响。结果证实：ＥＴ１可促进ＡＴⅡ的ＰＳ合成，激活ＰＫＣ上调ｃｆｏｓ基因表达是ＥＴ１促ＡＴⅡ细胞合成ＰＳ的胞内信号转导途径。

JNK-c-Jun/AP-1信号通路介导血管紧张素Ⅱ诱导的肾小球系膜细胞增殖

目的:探讨JNK-c-Jun/AP-1信号转导通路在血管紧张素Ⅱ(AngⅡ)诱导的肾小球系膜细胞(MC)增殖及细胞周期调控中的作用。方法:应用3H-胸腺嘧啶(3H-TdR)掺入法及流式细胞术测定MC增殖和细胞周期的变化。应用凝胶电泳迁移率(EMSA)和非放射性激酶活性检测法检测系膜细胞内活化蛋白-1(AP-1)及c-Jun氨基末端激酶(JNK)活性。结果:AngⅡ可呈时间依赖性地诱导MC内JNK活化,AngⅡ刺激30min后,JNK活性达到高峰,1h几乎恢复至正常水平;AngⅡ刺激后MC内AP-1活性显著增强,3H-TdR掺入量明显增加,S期和G2/M期细胞数显著增多;JNK特异性抑制剂SP600125显著抑制AngⅡ诱导AP-1活化及MC增殖。结论:AngⅡ→JNK/SAPK→c-Jun/AP-1信号通路在MC增殖中发挥一定的作用。JNK特异性抑制剂SP600125能部分抑制AngⅡ诱导的AP-1活化及细胞增殖,从而可能具有一定的治疗作用。

TNF-α通过JNK和AP-1途径调节乳腺癌MCF-7细胞VEGF的表达

目的:探讨肿瘤坏死因子(tumor necrosis factor-α,TNF-α)诱导血管内皮生长因子(vascular endothelial growth fac-tor,VEGF)表达的机制。方法:以20 ng/ml TNF-α处理MCF-7细胞,用Western blotting检测MAPK(JNK,p38,ERK)信号通路中蛋白磷酸化水平的变化以及AP-1家族(c-Jun,Jun-B,c-Fos,Fra-1,Fra-2,JunD)的蛋白表达及磷酸化水平的变化;以免疫共沉淀法检测激活后的AP-1存在形式;以RT-PCR以及Western blotting检测VEGF mRNA和蛋白表达水平;以MAPK抑制剂预处理后,检测VEGF蛋白表达水平;运用ChIP的方法验证p-c-Jun结合在VEGF启动子区。结果:TNF-α通过激活JNK信号转导通路活化AP-1;被TNF-α激活后AP-1以p-c-Jun-c-Jun和p-c-Jun-JunB同源二聚体形式存在;TNF-α通过激活转录因子AP-1促进VEGF的转录,并增强VEGF的蛋白表达水平;p-c-jun通过与VEGF启动子AP-1结合参与对VEGF转录的调控。结论:在TNF-α作用下,AP-1通过p-c-jun同源二聚体结合在VEGF启动子的AP-1结合位点上,直接对VEGF转录进行调控。

鞘氨醇激酶-1、C-反应蛋白对急性胰腺炎严重程度的预测价值

目的比较C-反应蛋白(CRP)和鞘氨醇激酶-1(SphK1)在预测急性胰腺炎(AP)严重程度方面的价值。方法选取2012年12月—2013年7月收治的30例AP患者,分为轻型AP(MAP)组17例和重型AP(SAP)组13例,另外纳入10例健康者作为健康对照组。AP患者在症状发生后、健康者在被选入组后48 h、72 h、5 d、7 d时分别检测血清CRP、外周血白细胞中SphK1 mRNA及其活性。结果 MAP组和SAP组患者血清CRP的水平、外周血白细胞中SphK1 mRNA、SphK1活性4个时间都高于健康对照组(P<0.05),但血清CRP的含量在MAP组和SAP组之间均无统计学差异(P>0.05)。48 h、72 h、5 d时,SAP组外周血白细胞中SphK1 mRNA、SphK1活性都高于MAP组(P<0.05);7 d时SAP组和MAP组的SphK1 mRNA、SphK1活性均无统计学差异(P>0.05)。在48 h时,SphK1的诊断灵敏度和诊断准确性最高,而且ROC曲线下面积高达0.946。结论在早期预测AP严重程度方面,与血清CRP相比,测定外周血白细胞中的SphK1是一个更好的方法。