Influence of bone morphogenetic proteins-2 and strontium chloride on the human umbilical cord mesenchymal stem cells proliferation and osteogenic differentiation

Objective To study the effects of combination of bone morphogenetic protein-2 (BMP-2) and strontium chloride on proliferation and osteogenic differentiation of human umbilical cord mesenchymal stem cells(hUCM-SCs)in vitro culture.

TM9SF1 is implicated in promoting the proliferation and invasion of bladder cancer cells

Zhuo et al looked into the part of transmembrane 9 superfamily member 1(TM9SF1)in bladder cancer(BC),and evaluated if it can be used as a therapeutic target.They created a permanent BC cell line and tested the effects of TM9SF1 overexpression and suppression on BC cell growth,movement,invasion,and cell cycle advancement.Their results show that TM9SF1 can boost the growth,movement,and invasion of BC cells and their access into the G2/M stage of the cell cycle.This research gives a novel direction and concept for targeted therapy of BC.

Novel Role of Calcium-Sensitive Receptors in Chronic Hypoxia-Induced Proliferation of Pulmonary Vein Smooth Muscle Cells

Objective:Vascular remodeling due to chronic hypoxia(CH)occurs not only in the pulmonary arteries but also in the pulmonary veins.Pulmonary vascular remodeling arises from the proliferation of pulmonary vascular myocytes.However,the mechanism by which CH induces the proliferation of pulmonary vein smooth muscle cells(PVSMCs)is unknown.This study aimed to investigate the mechanism by which CH affects the proliferation of PVSMCs.Methods:PVSMCs were isolated from rat distal pulmonary veins and exposed to CH(4%O2,60h),and the expression of the calcium-sensitive receptor(CaSR)was detected by Western blotting and immunofluorescence.MTT assay was used to detect the proliferation viability of the cells,and the changes in the intracellular calcium concentration were detected by laser confocal scanning technique.Results:CaSR expression was present in rat distal PVSMCs,and CaSR protein expression was upregulated under hypoxia.The positive regulator spermine not only enhanced CH-induced CaSR upregulation but also enhanced CH-induced increase in cell viability and calcium ion concentration.The negative CaSR regulator NPS2143 not only attenuated CH-induced CaSR upregulation but also inhibited CH-induced cell viability and calcium ion concentration.Conclusion:CaSR-mediated hyperproliferation is a novel pathogenic mechanism for the development of proliferation in distal PVSMCs under CH conditions.

Inhibitory Effect of Resveratrol on LPS-induced Glomerular Mesangial Cells Proliferation and TGF-β1 Expression via Sphingosine Kinase 1 Pathway

Objective To elucidate the renoprotective effect of resveratrol(RSV)on sphingosine kinase 1(SphK1)signaling pathway and expression of its downstream molecules including activator protein 1(AP-1)and transformation growth factor-β1(TGF-β1)in lipopolysaccharide(LPS)-induced glomerular mesangial cells(GMCs).Methods The rat GMCs line(HBZY-1)were cultured and randomly divided into 5 groups,including control,LPS(100 ng/mL),and 5,10,20µmol/L RSV-treated groups.In addition,SphK1 inhibitor(SK-II)was used as positive control.GMCs were pretreated with RSV for 2 h and treated with LPS for another 24 h.GMCs proliferation was determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide(MTT)assay.The proteins expression of SphK1,p-c-Jun and TGF-β1 in GMCs were detected by Western blot,and DNA-binding activity of AP-1 was performed by electrophoretic mobility shift assay(EMSA).The binding activity between RSV and SphK1 protein was detected by AutoDock Vina and visualized by Discovery Studio 2016.Results LPS could obviously stimulate GMCs proliferation,elevate SphK1,p-c-Jun and TGF-β1 expression levels and increase the DNA-binding activity of AP-1(P<0.05 or P<0.01),whereas these effects were significantly blocked by RSV pretreatment.It was also suggested that the effect of RSV was similar to SK-II(P>0.05).Moreover,RSV exhibited good binding affinity towards SphK1,with docking scores of−8.1 kcal/moL and formed hydrogen bonds with ASP-178 and LEU-268 in SphK1.Conclusion RSV inhibited LPS-induced GMCs proliferation and TGF-β1 expression,which may be independent of its hypoglycemic effect on preventing the development of mesangial cell fibrosis and closely related to the direct inhibition of SphK1 pathway.

AKT regulates IL-1β-induced proliferation and activation of hepatic stellate cells

Background:Activated hepatic stellate cells(HSCs)are closely involved in the initiation,perpetuation,and resolution of liver fibrosis.Pro-inflammatory cytokine levels are positively correlated with the transition from liver injury to fibrogenesis and contribute to HSC pathophysiology in liver fibrosis.Methods:In this study,we investigated the effect of the pro-inflammatory cytokine interleukin(IL)-1βon the proliferation and signaling pathways involved in fibrogenesis in LX-2 cells,an HSC cell line,using western blotting and cell proliferation assays.Results:IL-1βincreased the proliferation rate andα-smooth muscle actin(SMA)expression of LX-2 cells in a dose-dependent manner.Within 1 h after IL-1βtreatment,c-Jun N-terminal kinase(JNK),p38,and nuclear factor-κB(NF-κB)signaling was activated in LX-2 cells.Subsequently,protein kinase B(AKT)phosphorylation and an increase inα-SMA expression were observed in LX-2 cells.Each inhibitor of JNK,p38,or NF-κB decreased cell proliferation,AKT phosphorylation,andα-SMA expression in IL-1β-treated LX-2 cells.Conclusion:These results indicate that JNK,p38,and NF-κB signals converge at AKT phosphorylation,leading to LX-2 activation by IL-1β.Therefore,the AKT signaling pathway can be used as a target for alleviating liver fibrosis by the inflammatory cytokine IL-1β.

YWHAH activates the HMGA1/PI3K/AKT/mTOR signaling pathway by positively regulating Fra-1 to affect the proliferation of gastric cancer cells

Fos-related antigen 1(Fra-1)is a nuclear transcription factor that regulates cell growth,differentiation,and apoptosis.It is involved in the proliferation,invasion,apoptosis and epithelial mesenchymal transformation of malignant tumor cells.Fra-1 is highly expressed in gastric cancer(GC),affects the cycle distribution and apoptosis of GC cells,and participates in GC occurrence and development.However,the detailed mechanism of Fra-1 in GC is unclear,such as the identification of Fra-1-interacting proteins and their role in GC pathogenesis.In this study,we identified tyrosine 3-monooxygenase/tryptophan 5-monooxygenase activation protein eta(YWHAH)as a Fra-1-interacting protein in GC cells using co-immunoprecipitation combined with liquid chromatography-tandem mass spectrometry.Experiments showed that YWHAH positively regulated Fra-1 mRNA and protein expression,and affected GC cell proliferation.Whole proteome analysis showed that Fra-1 affected the activity of the high mobility group AT-hook 1(HMGA1)/phosphatidylinositol-4,5-bisphosphate 3-kinase(PI3K)/protein kinase B(AKT)/mechanistic target of rapamycin(mTOR)signaling pathway in GC cells.Western blotting and flow cytometry confirmed that YWHAH activated HMGA1/PI3K/AKT/mTOR signaling pathway by positively regulating Fra-1 to affect GC cell proliferation.These results will help to discover new molecular targets for the early diagnosis,treatment,and prognosis prediction of GC.

Study on the mechanism of tRNA-ValAAC-5 in promoting the proliferation and migration of hepatocellular carcinoma cells

Objective:To demonstrate the role and mechanism of tRNA-ValAAC-5 expression in hepatocellular carcinoma(HCC)cells.Methods:The expression levels of tRNA-ValAAC-5 in HCC(Hep3B,HuH7,SNU398,Hep3G2)and human hepatocellular carcinoma(THLE2,THLE3)were detected by real-time PCR.HEP3B and Hep3G2 cells were respectively transfected with tRNA-ValAAC-5-inhibitor and tRNA-ValAAC-5-NC as the inhibitor group and the NC group.Then the ability of cell proliferation was detected by CCK-8 assay and the ability of invasion and metastasis was detected by Transwell assay.The protein expression levels of p21,Matrix metalloproteinase 2(MMP2)and Matrix metalloproteinase 9(MMP9)were determined by Western blot.Results:The relative expression of tRNA-ValAAC-5 in Hep3B,HuH7,SNU398 and Hep3G2 cells were significantly higher than THLE2 and THLE3 cells,the differences were statistically significant(P<0.05).After tRNA-ValAAC-5-inhibitor transfection,the expression of tRNA-ValAAC-5 in Hep3B and Hep3G2 cells were reduced than tRNA-ValAAC-NC group.Both of the differences were statistically significant(t=36.52,27.45,P<0.001),which indicated the transfection was successful.The proliferative ability of Hep3B and Hep3G2 cells transfected with tRNA-ValAAC-5-inhibitor after 24,48,72,96 h were inhibited effectively compared with tRNA-ValAAC-5-NC group.All of the differences were statistically significant in Hep3B(t=5.25,8.23,7.33,14.16,P<0.001)and Hep3G2(t=4.25,5.11,9.39,7.59,P<0.001)cells.The number of invasion and metastasis of Hep3B and Hep3G2 cells were reduced in tRNA-ValAAC-5-inhibitor group compared with tRNA-ValAAC-5-NC group,there was significant difference(t=14.01,21.85,P<0.001).The protein expression levels of P21 were lower,MMP2 and MMP9 were higher in tRNA-ValAAC-5-inhibitor group compared with tRNA-ValAAC-5-NC group,the differences were statistically significant in Hep3B(t=8.96,12.80,4.652,P<0.001)cells and Hep3G2(t=15.17,22.36,12.61,P<0.001)cells.Conclusion:tRNA-ValAAC-5 can effectively promote the proliferation,invasion and metastasis of HCC,and its possible mechanism is related to regulating the expression of p21,MMP2 and MMP9.

Inhibitory Effects of Propolis Water Extract on the Proliferation of Cervical Cancer Cells

[Objectives]To investigate the effects of propolis extract on HeLa cells to provide theoretical guidance for facilitating clinical treatment.[Methods]The effects of propolis on inflammation,and proliferation were analyzed based on the levels of DNA transcriptional regulation and mRNA and protein expression levels.[Results]Propolis water extract(PWE)could inhibit the cell proliferation and production of DNA damage in a dosedependent manner.Moreover,the propolis water extract could significantly downregulate the expression of iNOS-Luc,PTGS-2-Luc,and IL-8-Luc,and that it was related to the expression of the NF-κB family protein.After the induction of HeLa cells by propolis,the expression of the cell cycle inhibitor gene p21 was increased,while that of the cell proliferation gene Ki67 was decreased.[Conclusions]Propolis water extract could significantly inhibit the cell proliferation and production of DNA damage,suggesting propolis as a potential candidate for the development of adjunctive therapy against cervical cancer.

Exosome-Transmitted miR-224-5p Promotes Colorectal Cancer Cell Proliferation via Targeting ULK2 in p53-Dependent Manner

Objective To investigate the role and molecular mechanism of exosomal miR-224-5p in colorectal cancer(CRC).Methods The miR-224-5p expression in CRC patient tissues and cell-derived exosomes was measured by laser capture microdissection and qRT-PCR,respectively.Dual-luciferase reporter gene assay was used to determine the target gene of miR-224-5p.The protein expressions of p53 and unc-51 like kinase 2(ULK2)in CRC cells were detected by western blot.Flow cytometry was used to detect cell cycle and apoptosis.Cell proliferation was measured by CCK8 and EdU assay.Results The miR-224-5p expression was upregulated in CRC tissues and increased progressively with the rise of CRC stage.CRC cells secreted extracellular miR-224-5p mainly in an exosome-dependent manner,and then miR-224-5p could be transferred to surrounding tumor cells to regulate cell proliferation in the form of autocrine or paracrine.Moreover,ULK2 was characterized as a direct target of miR-224-5p and was downregulated in CRC tissues.Interestingly,ULK2 inhibited CRC cell proliferation in a p53-dependent manner.Furthermore,exosome-derived miR-224-5p partially reversed the proliferation regulation of ULK2 on CRC cells.Conclusion Our findings demonstrate that exosome-transmitted miR-224-5p promotes p53-dependent cell proliferation by targeting ULK2 in CRC,which may offer promising targets for CRC prevention and therapy.

High-frequency repetitive transcranial magnetic stimulation promotes neural stem cell proliferation after ischemic stroke

Prolife ration of neural stem cells is crucial for promoting neuronal regeneration and repairing cerebral infarction damage.Transcranial magnetic stimulation(TMS)has recently emerged as a tool for inducing endogenous neural stem cell regeneration,but its underlying mechanisms remain unclea r In this study,we found that repetitive TMS effectively promotes the proliferation of oxygen-glucose deprived neural stem cells.Additionally,repetitive TMS reduced the volume of cerebral infa rction in a rat model of ischemic stro ke caused by middle cerebral artery occlusion,im p roved rat cognitive function,and promoted the proliferation of neural stem cells in the ischemic penumbra.RNA-sequencing found that repetitive TMS activated the Wnt signaling pathway in the ischemic penumbra of rats with cerebral ischemia.Furthermore,PCR analysis revealed that repetitive TMS promoted AKT phosphorylation,leading to an increase in mRNA levels of cell cycle-related proteins such as Cdk2 and Cdk4.This effect was also associated with activation of the glycogen synthase kinase 3β/β-catenin signaling pathway,which ultimately promotes the prolife ration of neural stem cells.Subsequently,we validated the effect of repetitive TMS on AKT phosphorylation.We found that repetitive TMS promoted Ca2+influx into neural stem cells by activating the P2 calcium channel/calmodulin pathway,thereby promoting AKT phosphorylation and activating the glycogen synthase kinase 3β/β-catenin pathway.These findings indicate that repetitive TMS can promote the proliferation of endogenous neural stem cells through a Ca2+influx-dependent phosphorylated AKT/glycogen synthase kinase 3β/β-catenin signaling pathway.This study has produced pioneering res ults on the intrinsic mechanism of repetitive TMS to promote neural function recove ry after ischemic stro ke.These results provide a stro ng scientific foundation for the clinical application of repetitive TMS.Moreover,repetitive TMS treatment may not only be an efficient and potential approach to support neurogenesis for further therapeutic applications,but also provide an effective platform for the expansion of neural stem cells.

PbGIF1 promoting cell-proliferation in pear fruit is transcriptionally activated by Pb RR1

As a cell proliferation regulator involved in wide biological processes in plants,GRF-INTERACTING FACTOR(GIF)controls different tissues development.However,whether GIF participates in fruit development remains unclear.According to transcriptome data,we identified PbGIF1was highly expressed during fruit development in cytokinins induced parthenocarpy pear.In the present study,the biofunction of PbGIF1 was initially verified.Overexpression of PbGIF1 promoted fruit size of transgenic tomato.The size of flesh fruit was not affected by cell expansion but the cell proliferation was promoted by overexpressing Pb GIF1.The accelerated cell proliferation process was also observed in PbGIF1-overexpressed transgenic pear fruit calli.The transcriptional regulation of cytokinins on PbGIF1 was further confirmed by exogenous CPPU treatments in pear fruitlets.To investigate the underlying mechanism,the cytokinins-responded factor,PbRR1,was further focused on.The results of Yeast-one-hybrid assay suggested that PbRR1 can bind to the promoter sequence of PbGIF1.The transcriptional activation of PbRR1 on PbGIF1 was also confirmed by Dual-Luciferase assays.Taken together,the results showed that cytokinins control pear fruit development via the transcriptional activation of PbGIF1 by PbRR1.

Knockdown of circular RNA (CircRNA)_001896 inhibits cervical cancer proliferation and stemness in vivo and in vitro

Objective:Previous studies indicated that aberrant circular RNA(circRNA)expression affects gene expression regulatory networks,leading to the aberrant activation of tumor pathways and promoting tumor cell growth.However,the expression,clinical significance,and effects on cell propagation,invasion,and dissemination of circRNA_001896 in cervical cancer(CC)tissues remain unclear.Methods:The Gene Expression Omnibus(GEO)datasets(GSE113696 and GSE102686)were used to examine differential circRNA expression in CC and adjacent tissues.The expression of circRNA_001896 was detected in 72 CC patients usingfluorescence quantitative PCR.Correlation analysis with clinical pathological features was performed through COX multivariate and univariate analysis.The effect of circRNA_001896 downregulation on CC cell propagation was examined using the cell counting kit-8(CCK-8)test,clonogenic,3D sphere formation,and in vivo tumorigenesis assays.Results:Intersection of the GSE113696 and GSE102686 datasets revealed an increased expression of four circRNAs,including circRNA_001896,in CC tissues.Fluorescence quantitative PCR confirmed circRNA_001896 as a circular RNA.High expression of circRNA_001896 was considerably associated with lymph node metastasis,International Federation of Gynecologists and Obstetricians(FIGO)stage,tumor diameter,and survival period in CC patients.Proportional hazards model(COX)univariate and multivariate analyses revealed that circRNA_001896 expressions are a distinct risk factor affecting CC patients’prognosis.Cellular functional experiments showed that downregulating circRNA_001896 substantially suppressed CC cell growth,colony formation,and 3D sphere-forming ability.In vivo,tumorigenesis analysis in nude mice demonstrated that downregulating circRNA_001896 remarkably reduced the in vivo proliferation capacity of CC cells.Conclusion:CircRNA_001896 is highly expressed in CC tissues and is substantially related to lymph node metastasis,FIGO stage,tumor size,and survival period in patients.Moreover,downregulating circRNA_001896 significantly inhibits both in vivo and in vitro propagation of CC cells.Therefore,circRNA_001896 might be used as a biomarker for targeted therapy in cervical cancer.

Expansion of human umbilical cord derived mesenchymal stem cells in regenerative medicine

BACKGROUND Stem cells are undifferentiated cells that possess the potential for self-renewal with the capacity to differentiate into multiple lineages.In humans,their limited numbers pose a challenge in fulfilling the necessary demands for the regeneration and repair of damaged tissues or organs.Studies suggested that mesenchymal stem cells(MSCs),necessary for repair and regeneration via transplantation,require doses ranging from 10 to 400 million cells.Furthermore,the limited expansion of MSCs restricts their therapeutic application.AIM To optimize a novel protocol to achieve qualitative and quantitative expansion of MSCs to reach the targeted number of cells for cellular transplantation and minimize the limitations in stem cell therapy protocols.METHODS Human umbilical cord(hUC)tissue derived MSCs were obtained and re-cultured.These cultured cells were subjected to the following evaluation pro-cedures:Immunophenotyping,immunocytochemical staining,trilineage differentiation,population doubling time and number,gene expression markers for proliferation,cell cycle progression,senescence-associatedβ-galactosidase assay,human telomerase reverse transcriptase(hTERT)expression,mycoplasma,cytomegalovirus and endotoxin detection.RESULTS Analysis of pluripotent gene markers Oct4,Sox2,and Nanog in recultured hUC-MSC revealed no significant differences.The immunophenotypic markers CD90,CD73,CD105,CD44,vimentin,CD29,Stro-1,and Lin28 were positively expressed by these recultured expanded MSCs,and were found negative for CD34,CD11b,CD19,CD45,and HLA-DR.The recultured hUC-MSC population continued to expand through passage 15.Proliferative gene expression of Pax6,BMP2,and TGFb1 showed no significant variation between recultured hUC-MSC groups.Nevertheless,a significant increase(P<0.001)in the mitotic phase of the cell cycle was observed in recultured hUC-MSCs.Cellular senescence markers(hTERT expression andβ-galactosidase activity)did not show any negative effect on recultured hUC-MSCs.Additionally,quality control assessments consistently confirmed the absence of mycoplasma,cytomegalovirus,and endotoxin contamination.CONCLUSION This study proposes the development of a novel protocol for efficiently expanding stem cell population.This would address the growing demand for larger stem cell doses needed for cellular transplantation and will significantly improve the feasibility of stem cell based therapies.

Mechanism of stilbene glycosides on apoptosis of SH-SY5Y cells via regulating PI3K/AKT signaling pathway

Objective:To investigate the effects of stilbene glycoside(TSG)on okadaic acid-induced apoptosis in human neuroblastoma cells(SH-SY5Y)via the PI3K/AKT pathway.Methods:The optimal concentration of OA was screened by CCK-8 assay,and SH-SY5Y cells were divided into control group,model group,TSG group,LY294002 group and LY294002+TSG group.The proliferation and apoptosis in each group were detected by CCK-8 and TUNEL assays;Western blotting method and real-time fluorescence quantitative polymerase chain reaction was used to detect the expression of PI3K,P-PI3K(Y607),AKT,P-AKT(Ser473),Bcl-2 and Bax proteins.The relative protein expression was represented by P-PI3K(Y607)/PI3K,P-AKT(Ser473)/AKT and Bcl-2/Bax gray ratio.Results:CCK-8 screened the optimal concentration of OA as 40 nmol/L.Compared with the control group,the model group increased relative cell viability,decreased apoptosis rate,the pathway and apoptotic proteins expression levels of P-PI3K(Y607)/PI3K,P-AKT(Ser473)/AKT and Bcl-2/Bax were decreased,and the mRNA expression levels of PI3K,AKT and Bcl-2 were decreased.Bax mRNA expression level increased(P<0.05);Compared with model group,TSG group increased relative cell viability,decreased apoptosis rate,increased protein expression levels of P-PI3K(Y607)/PI3K,P-AKT(Ser473)/AKT,Bcl-2/Bax,and increased mRNA expression levels of PI3K,AKT,and Bcl-2.Bax mRNA expression decreased(P<0.05),LY294002 group decreased relative cell viability,increased apoptosis rate,P-PI3K(Y607)/PI3K protein expression levels were significantly decreased(P<0.05),P-AKT(Ser473)/AKT and Bcl-2/Bax protein expression levels were significantly decreased,but there was no statistical significance,PI3K,AKT and Bcl-2 mRNA expression levels were decreased,and Bax mRNA expression levels were increased(all P<0.05);Compared with LY294002 group,LY294002+TSG group increased relative cell viability,decreased apoptosis rate,and the protein expression levels of P-PI3K(Y607)/PI3K,P-AKT(Ser473)/AKT and Bcl-2/Bax were increased.The mRNA expression levels of PI3K,AKT,Bcl-2 were increased,Bax was decreased(all P<0.05).Conclusion:Stilbene glycoside may alleviate okadaic acid-induced apoptosis in SH-SY5Y cells by interfering with the PI3K/AKT signaling pathway,which in turn regulates the expression of apoptotic factors such as Bcl-2 and Bax.

The Effects of High-intensity Pulsed Electromagnetic Field on Proliferation and Differentiation of Neural Stem Cells of Neonatal Rats in vitro

The effects of high-intensity pulsed electromagnetic stimulation （HIPEMS） on proliferation and differentiation of neonatal rat neural stem cells in vitro were investigated. Neural stem cells derived from neonatal rats were exposed to 0.1 Hz, 0.5–10 Tesla （T） [8 groups of B–I, respectively], 5 stimuli of HIPEMF. The sham exposure controls were correspondingly established. Inverted phase contrast microscope was used to observe the cultured cells, MTT assay to detect the viability of the cells as expressed by absorbance （A） value, and flow cytometry to measure differentiation of neural stem cells. The results showed that A values of neural stem cells in both 3.0 T and 4.0 T groups were significantly higher than the other groups 24 to 168 h post HPEMS, indicating a strong promotion of the growth of neural stem cells （P〈0.05）. The A values of neural stem cells in the 6.0 T, 8.0 T, and 10.0 T groups were lower than the sham exposure control group, indicating a restraint of the growth of neural stem cells. The rate of neuron-specific enolase-positive neurons revealed by flow cytometry in HPEMS groups was the same as that in control group （P〉0.05）. It was suggested that 0.1 Hz, 5 pulses stimulation of HPEMS within certain scale of intensity （0.5–10.0 T）, significantly promoted the growth of neural stem cells with the rational intensity being 4.0 T.

Short-term environmental enrichment exposure induces proliferation and maturation of doublecortin-positive cells in the prefrontal cortex

Previous studies have demonstrated that doublecortin-positive immature neurons exist pre- dominantly in the superficial layer of the cerebral cortex of adult mammals such as guinea pigs, and these neurons exhibit very weak properties of self-proliferation during adulthood under physiological conditions. To verify whether environmental enrichment has an impact on the proliferation and maturation of these immature neurons in the prefrontal cortex of adult guinea pigs, healthy adult guinea pigs were subjected to short-term environmental enrichment. Animals were allowed to play with various cognitive and physical stimulating objects over a period of 2 weeks, twice per day, for 60 minutes each. Immunofluorescence staining results indicated that the number of doublecortin-positive cells in layer II of the prefrontal cortex was significantly increased after short-term environmental enrichment exposure. In addition, these doublecortin-positive cells co-expressed 5-bromo-2-deoxyuridine （a marker of cell prolifera- tion）, c-Fos （a marker of cell viability） and NeuN （a marker of mature neurons）. Experimental findings showed that short-term environmental enrichment can induce proliferation, activation and maturation of doublecortin-positive cells in layer II of the prefrontal cortex of adult guinea pigs.

Low-power laser irradiation promotes the proliferation and osteogenic differentiation of human periodontal ligament cells via cyclic adenosine monophosphate

Retaining or improving periodontal ligament （PDL） function is crucial for restoring periodontal defects. The aim of this study was to evaluate the physiological effects of low-power laser irradiation （LPLI） on the proliferation and osteogenic differentiation of human PDL （hPDL） cells. Cultured hPDL cel Is were irradiated （660 nm） daily with doses of O, 1, 2 or 4 J .cm-2. Cell proliferation was evaluated by the 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide （MTT） assay, and the effect of LPLI on osteogenic differentiation was assessed by Alizarin Red S staining and alkaline phosphatase （ALP） activity. Additionally, osteogenic marker gene expression was confirmed by real-time reverse transcription-polymerase chain reaction （RT-PCR）. Our data showed that LPLI at a dose of 2 J.cm-2 significantly promoted hPDL cell proliferation at days 3 and 5. In addition, LPLI at energy doses of 2 and 4 J.cm-2 showed potential osteogenic capacity, as it stimulated ALP activity, calcium deposition, and osteogenic gene expression. We also showed that cyclic adenosine monophosphate （cAMP） is a critical regulator of the LPLI-mediated effects on hPDL cells. This study shows that LPLI can promote the proliferation and osteogenic differentiation of hPDL cells. These results suggest the potential use of LPLI in clinical applications for periodontal tissue regeneration.

Influence of norcantharidin on proliferation,proliferation-related gene proteins prolifera-ting cell nuclear antigen and Ki-67 of human gallbladder carcinoma GBC-SD cells

BACKGROUND: Gallbladder carcinoma is a highly lethal and aggressive disease with early metastasis, strong invasion and poor prognosis. Most patients with this disease are at the advanced and un-resectable stage and should be consi- dered for palliative treatment such as chemotherapy and ra- diotherapy. Unfortunately, reports of chemotherapy and radiotherapy for gallbladder carcinoma are disappointing. We investigated the influence of norcantharidin (NCTD) on proliferation, proliferation-related gene proteins PCNA and Ki-67 of human gallbladder carcinoma GBC-SD cells in vitro. METHODS: GBC-SD cell lines of human gallbladder carci- noma were cultured by the cell culture technique. The ex- periment was divided into NCTD group and control group. The tetrazolium-based colorimetric assay was used to evaluate cell growth. The streptavidin-biotin complex method was used to determine the expressions of prolifera- tion-related gene proteins PCNA and Ki-67 of human gall- bladder carcinoma GBC-SD cells. RESULTS: NCTD inhibited the growth and proliferation of GBC-SD cells from 10 mg/L or after 6 hours in a dose- and time-dependent manner, with the IC50 value of 56.18 μg/ ml at 48 hours. After treatment with NCTD, the expression of PCNA (0.932 ±0.031 vs. 0.318 ±0.023, P<0.001) and Ki-67 (0.964 ±0.092 vs. 0.297 ±0.018, P<0.001) proteins were decreased significantly. CONCLUSION: NCTD inhibits the proliferation of human gallbladder carcinoma GBC-SD cells in vitro and the expres- sion of their proliferation-related gene proteins PCNA and Ki-67.

Senegenin promotes in vitro proliferation of human neural progenitor cells

Senegenin, an effective component of Polygala tenuifolia root extract, promotes proliferation and differentiation of neural progenitor cells in the hippocampus. However, the effects of senegenin on mesencephalon-derived neural progenitor cells remain poorly understood. Cells from a ventral mesencephalon neural progenitor cell line （ReNcell VM） were utilized as models for pharmaceutical screening. The effects of various senegenin concentrations on cell proliferation were analyzed, demonstrating that high senegenin concentrations （5, 10, 50, and 100 μmol/L）, particularly 50 μmol/L, significantly promoted proliferation of ReNcell VM cells. In the mitogen-activated protein kinase signal transduction pathway, senegenin significantly increased phosphorylation levels of extracellular signal-regulated kinases. Moreover, cell proliferation was suppressed by extracellular signal-regulated kinase inhibitors. Results suggested that senegenin contributed to in vitro proliferation of human neural progenitor cells by upregulating phosphorylation of extracellular signal-regulated kinase.

Cigarette smoke extract promotes human pulmonary artery smooth muscle cells proliferation through protein kinase C alpha-dependent induction of cyclin D1

Background Exposure to cigarette smoke stimulates the proliferation of human pulmonary artery smooth muscle cells （HPASMCs） in vivo and in vitro. However, the molecular mechanism remains unclear. This study aimed at investigating the role of signaling pathways involving protein kinase C alpha （PKCα） and cyclin D1 in the cigarette smoke extract （CSE）-induced HPASMCs proliferation.Methods Synchronized HPASMCs were treated with different concentrations of CSE. Cell proliferation was evaluated by 3-（4,5-dimethylthiazol-2-yl）-2,5-diphenyttetrazolium bromide （MTT） assay and cell counting. Cell cycle was analyzed by flow cytometry with propidium iodide staining. Activation of PKCα was measured by detecting the expression of PKCαprotein in the cytosolic and membrane fractions using Western blotting analysis. Small interfering RNA （siRNA） was used to knockdown PKCα and cyclin D1. The cyclin D1 mRNA was assessed by real-time RT-PCR. The PKCα and cyclin D1protein levels were detected by Western blotting.Results Low concentrations of CSE （1%-10%） stimulated proliferation of HPASMCs, with its maximal effect at 5%.CSE （5%） led to PKCα activation. Inhibition of PKCα activity using G（o） 6976 or siRNA-mediated knockdown of PKCα significantly attenuated CSE-induced cell proliferation and G1/S transition. Cyclin D1, one of key regulators of G1/S transition, was found to be upregulated by 5% CSE at both the mRNA and protein levels. CSE-stimulated cellproliferation and G1/S transition was abolished by cyclin D1 siRNA. Moreover, G（o） 6976 or PKCα siRNA significantlysuppressed CSE-induced upregulation of cyclin D1 at both the mRNA and protein levels.Conclusion PKCα-cyclin D1 pathway at least partially mediates the CSE-induced proliferation in HPASMCs.