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BACKGROUND: Previous study demonstrated that hypoxia preconditioning promoted mesenchymal stem cells survival and their therapeutic efficacy, and this effect was mediated by hypoxia induced factor-1α (HIF-1α). However, specific downstream mechanism remained unclear. OBJECTIVE: To observe the influence of hypoxia preconditioning on the survival and vascularization potential of bone marrow mesenchymal stem cells in vitro and explore the regulatory mechanism of HIF-1α/MALAT1/VEGFA pathway. METHODS: Bone marrow mesenchymal stem cells were obtained and cultured in vitro. Cells were divided into hypoxia (1% O2) and normoxia control groups (20% O2), and cultured for 24 hours. Cells proliferation, apoptosis and vascularization were evaluated. The expression of HIF-1α, MALAT1, and VEGFA was detected. HIF-1α and MALAT1 were inhibited by their siRNAs separately. HIF-1α siRNA scramble and MALAT1 siRNA scramble were used as negative controls before hypoxia preconditioning. Alterations of the molecules were examined and compared in different groups. RESULTS AND CONCLUSION: (1) Compared with the normoxia control group, cell viability was significantly enhanced; and cell apoptosis percentage was significantly declined in the hypoxia group; vascular lumen like structure was also increased significantly in the hypoxia group (P < 0.01); expression of HIF-1α, MALAT1, and VEGFA was significantly increased in the hypoxia group (P < 0.01). (2) After the inhibition of HIF-1α and hypoxia preconditioning, both MALAT1 and VEGFA expression levels were significantly reduced (P < 0.01). The expression of VEGFA was also significantly suppressed after the blockage of MALAT1 (P < 0.01). (3) This study suggested that hypoxia preconditioning effectively promoted bone marrow mesenchymal stem cell survival and vascularization through the activation of HIF-1α/MALAT1/VEGFA pathway.
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Objective: The aim of this study is to probe in the inhibitory effects of ginsenoside Rg3 on the expression of hypoxia-induced factor-1α (HIF-1α) and vascular endothelial growth factor (VEGF) in human gastric cancer cells. Materials and Methods: Human gastric cancer BGC823 cells were divided into the control group and experiment group, and expression levels of HIF-1α and VEGF were detected by immunocytochemistry and Western blot after cells were cultured under hypoxia for different durations. Results: Under hypoxia, expression of HIF-1α and VEGF in human gastric cancer BGC823 cells showed an increasing trend, and that was remarkably lower in experiment group than in the control group after applying Rg3, which was obvious at 12 and 24 h (P < 0.05). Conclusion: Rg3 can inhibit expression of HIF-1α and VEGF in human gastric cancer cells and may influence abdominal implantation metastasis of gastric cancer through inhibiting its expression
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Objective To study the expression and the clinical significance of hypoxia-induced factor-1α (HIF-1α) in gallbladder cancer tissues,and the role and mechanism of HIF-1α in metformin-suppressed metastasis in gallbladder carcinoma GBC-SD cells.Methods 24 specimens of gallbladder cancer tissues and 5 specimens of chronic cholecystitis were collected from the First Affiliated Hospital of Zhengzhou University between June 2016 and February 2017.Immunohistochemistry and qPCR were used to detect the expression of HIF-1α in gallbladder cancer tissues,in adjacent non-cancer tissues and in chronic cholecystitis,and the clinical significance was analyzed.The model of metastasis was induced by hypoxia;the wound healing assay and the Transwell assay were used to detect the ability of cell metastasis;the expressions of HIF-1α and VEGF in gallbladder carcinoma GBC-SD cells were detected by western blotting assay and immunofiuorescence.Results The expression of HIF-1α in gallbladder cancer tissues was higher than the adjacent non-cancer tissues and in chronic cholecystitis.The expression of HIF-1α was correlated with lymph node metastasis and TNM staging in gallbladder cancer tissues (P ＜ 0.05).The wound healing rate after 48 h in the negative control group and in the treatment with hypoxia group (1％ O2) in GBC-SD cells were (46.5 ± 4.8) ％ and (67.3 ± 4.0) ％,respectively.The Transwell data showed that the numbers of metastasis after 24 h in the negative control group and in the treatment with hypoxia group GBC-SD cells were (147.4 ± 11.7) and (234.4 ± 17.7),respectively.When compared with the negative control group,treatment with hypoxia significantly increased the ability of metastasis and up-regulated the expression of HIF-1α and VEGF in GBC-SD cells (P ＜ 0.05).The wound healing rate after 48 h in the negative control group,the metformin group,the hypoxia group and the metformin and hypoxia group in GBC-SD cells were (40.6 ± 7.1) ％,(16.4 ± 9.4) ％,(69.5 ± 4.0) ％ and (22.4 ± 7.4) ％,respectively.The Transwell data showed that the numbers of metastasis after 24 h in the negative control group,the metformin group,the hypoxia group and the metformin and hypoxia group in GBC-SD cells were (148.4 ± 6.9),(90.0 ± 8.4),(185.8 ± 10.2) and (113.4± 8.6),respectively.When comparcd with the hypoxia group,treatment with metformin and hypoxia significantly decreased the ability of metastasis and down-regulated the expression of HIF-1α and VEGF in GBC-SD cells (P ＜ 0.05).The wound healing rate after 48 h in the negative control group,the 2MeoE2 group,the hypoxia group,the 2MeoE2 and hypoxia group in GBC-SD cells were (43.4 ±4.4)％,(25.9 ±9.0)％,(63.3 ±2.2)％,(46.2 ±4.5)％,respectively.The Transwell data showed that the numbers of metastasis after 24 h in the negative control group,the 2MeoE2 group,the hypoxia group,the 2MeoE2 and hypoxia group in GBC-SD cells were (144.2 ± 12.6),(80.2 ±7.7),(203.8 ±7.0),(124.0 ± 5.2),respectively.When compared with the hypoxia group,treatment with HIF-1α inhibitor 2MeoE2 and hypoxia significantly decreased the ability of metastasis and down-regulated the expression of HIF-1α and VEGF in GBC-SD cells (P ＜ 0.05).Conclusions The expression of HIF-1 α was correlated with lymph node metastasis and TNM staging in gallbladder cancer tissues.Treatment with hypoxia significantly increased the expression of HIF-1α and VEGF and promoted metastasis of GBC-SD cells,while treatment with metformin decreased the ability of metastasis induced by hypoxia via inhibiting the HIF-1o/VEGF pathway in GBC-SD cells.
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Objective To investigate the role of hypoxia induced factor-1 α (HIF-1 α) signaling pathway in development of nonacoholic fatty liver disease (NAFLD) by using a rat model.Methods Forty SD rats were randomly divided into 5 groups (normal control group,4 weeks model group,8 weeks model group,12 weeks model group,and 16 weeks model group according to random number table).NAFLD model was induced by high fat diet.Serum biochemical parameters and liver histological examinations were observed.The HIF-1α,peroxisome proliferator-activated receptor α (PPARα),and nuclear factor-κB (NF-κB) mRNA transcriptions of liver tissue were detected with realtime PCR.Results Compared with the control group,a remarkable rise of serum alanine amiotransferase,triglyceride,cholesterol,and reduction of high density lipoprotein-cholesterol were observed in rats treated with high fat diet after 12 weeks and 16 weeks (P＜0.05).Compared with model group,steatosis,grade of inflammation,and degree of fibrosis in the liver were also significantly aggravated.Fed with high fat diet for 8 weeks,the expression of HIF-1α was significantly higher than that in the control group;the expression of PPARα in 4 weeks group was significantly higher than that in the control group.The expression of PPARα was again significantly elevated in 16 weeks group (P＜0.05);NF-κB expression was increased gradually with high fat diet (P＜0.05).The expression of HIF-1 α mRNA was related with PPARα (r =0.82,P＜0.05) and NF-κB (r =0.67,P＜0.05),and PPARα mRNA was related with NF-κB (r =0.78,P＜0.05).Conclusion HIF-1 α signaling may regulate PPARα/NF-κB and seems to be related with development of NAFLD.
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Objective To investigate the effects of exogenous hydrogen sulfide (H2S) on injury of rat hippocampus neurons induced by oxygen-glucose deprivation and restoration (OGD/R) and explore its mechanism.Methods Hippocampus neurons were isolated from embryonic day 16-18 (E16-18) rat embryos.Hippocampus was immediately removed and digested with 0.25％ trypsin.The neurons were isolated and cultured at 37 ℃ for 7 days and neuron-specific enolase (NSE) was detected by immunohistochemical staining method to identify neurons.At 8th day,the neurons were placed in deoxygenated glucose-free medium and exposed to 95％ N2-5％ CO2 in an air tight chamber for 1 hour,and then replaced the glucose-free medium with original medium,and returned the cultures to a standard incubator in 5％ CO2 at 37 ℃ and incubated for another 24 h.The neurons were divided into 3 groups:group Ⅰ control; group Ⅱ OGD/R,and group ⅢOGD + NaHS,the latter was further divided into 5 subgroups:groups Ⅲ1-5 with 25,50,100,200,400 μmol/L NaHS added,respectively.Then cell viability was quantified by MTT method,the level of lactate dehydrogenase (LDH) were detected,apoptosis was measured by Annexin V FITC/PI Apoptosis Kits,and RT-PCR was used to assay HIF-1 α mRNA in neurons in all groups.Results Compared with control group,the LDH level,apoptosis and expression of HIF-1α mRNA in group Ⅱ were significantly increased,the cell viability was significantly decreased (P ＜ 0.01).There were no significant differences in the LDH level,apoptosis and expression of HIF-1 α mRNA and the cell viability between group Ⅱ and group Ⅲ1 (P ＞ 0.05).Compared with group Ⅱ,the LDH level,apoptosis and expression of HIF-1α mRNA in group Ⅲ2-4 were significantly increased,the cell viability was significantly increased (P ＜ 0.01).Compared with group Ⅱ,the LDH level,apoptosis and expression of HIF-1 α mRNA in the group Ⅲ 5 were significantly decreased,the cell viability was significantly decreased (P ＜ 0.01).Conclusions H2S of low concentration has no significant effects on injury of rat hippocampus neurons induced by OGD/R.H2S of moderate doses can protect rat hippocampus neurons from OGD/R injury and H2S of high concentration can aggravate injury.The expression of HIF-1α mRNA in rat hippocampus neurons was increased after OGD/R,and the protective role of H2S is associated with increase in the expression of HIF-1α mRNA.