Effects of leptin on proliferation and differentiation of hypoxic rat retinal progenitor cells in vitro / 南方医科大学学报

OBJECTIVE@#To investigate the the effects of leptin on the proliferation, differentiation and PTEN expression of rat retinal progenitor cells (RPCs) cultured under hypoxic condition.@*METHODS@#SD rat RPCs were cultured in normoxic conditions or exposed to hypoxia in the presence of 0, 0.3, 1.0, 3.0, 10, and 30 nmol/L leptin for 12, 48 and 72 h, and the cell viability was assessed using cell counting kit 8 (CCK 8) assay. The RPCs in primary culture were divided into control group, hypoxia group, and hypoxia+leptin group, and after 48 h of culture, the cell medium was replaced with differentiation medium and the cells were further cultured for 6 days. Immunofluorescence staining was employed to detect the cells positive for β-tubulin III and GFAP, and Western blotting was used to examine the expression of PTEN at 48 h of cell culture.@*RESULTS@#The first generation of RPCs showed suspended growth in the medium with abundant and bright cellular plasma and formed mulberry like cell spheres after 2 days of culture. Treatment with low-dose leptin (below 3.0 nmol/L) for 48 h obviously improved the viability of RPCs cultured in hypoxia, while at high concentrations (above 10 nmol/L), leptin significantly suppressed the cell viability (P < 0.05). The cells treated with 3.0 nmol/L leptin for 48 h showed the highest viability (P < 0.05). After treatment with 3.0 nmol/L leptin for 48 h, the cells with hypoxic exposure showed similar GFAP and β-tubulin Ⅲ positivity with the control cells (P>0.05), but exhibited an obvious down-regulation of PTEN protein expression compared with the control cells (P < 0.05).@*CONCLUSION@#In rat RPCs with hypoxic exposure, treatment with low dose leptin can promote the cell proliferation and suppress cellular PTEN protein expression without causing significant effects on cell differentiation.

Transition of autophagy and apoptosis in fibroblasts depends on dominant expression of HIF-1α or p53 / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

It has been revealed that hypoxia is dynamic in hypertrophic scars; therefore, we considered that it may have different effects on hypoxia-inducible factor-1α (HIF-1α) and p53 expression. Herein, we aimed to confirm the presence of a teeterboard-like conversion between HIF-1α and p53, which is correlated with scar formation and regression. Thus, we obtained samples of normal skin and hypertrophic scars to identify the differences in HIF-1α and autophagy using immunohistochemistry and transmission electron microscopy. In addition, we used moderate hypoxia in vitro to simulate the proliferative scar, and silenced HIF-1α or p53 gene expression or triggered overexpression to investigate the changes of HIF-1α and p53 expression, autophagy, apoptosis, and cell proliferation under this condition. HIF-1α, p53, and autophagy-related proteins were assayed using western blotting and immunofluorescence, whereas apoptosis was detected using flow cytometry analysis, and cell proliferation was detected using cell counting kit-8 (CCK-8) and 5-bromo-2'-deoxyuridine (BrdU) staining. Furthermore, immunoprecipitation was performed to verify the binding of HIF-1α and p53 to transcription cofactor p300. Our results demonstrated that, in scar tissue, HIF-1α expression increased in parallel with autophagosome formation. Under hypoxia, HIF-1α expression and autophagy were upregulated, whereas p53 expression and apoptosis were downregulated in vitro. HIF-1α knockdown downregulated autophagy, proliferation, and p300-bound HIF-1α, and upregulated p53 expression, apoptosis, and p300-bound p53. Meanwhile, p53 knockdown induced the opposite effects and enhanced HIF-1α, whereas p53 overexpression resulted in the same effects and reduced HIF-1α. Our results suggest a teeterboard-like conversion between HIF-1α and p53, which is linked with scar hyperplasia and regression.

Effect of Hypoxia Inducible Factor-1α on Chemosensitivity of B-ALL Cells to Vincristine and Its Mechanism / 中国实验血液学杂志

OBJECTIVE@#To explore the effect of hypoxia on the chemosensitivity of B-acute lymphoblastic leukemia （B-ALL） cells to Vincristine (VCR) and the mechanisms.@*METHODS@#B-ALL cells SUP-B15, Nalm-6 and RS4;11 were selected as the research objects. The cells were divided into the control group and the hypoxia mimic group (CoCl2 pretreatment). The two groups were treated with VCR at different concentrations for 24 hours, CCK-8 was used to detect cell viability, flow cytometry was used to detect cell apoptosis, and Western bolt method was used to detect hypoxia inducible factor (HIF-1α), BAX, Bcl-2 and β-actin protein expression. Quantitative real-time fluorescent PCR (qRT-PCR) was used to detect BAX and β-actin mRNA levels.@*RESULTS@#CoCl2 could simulate hypoxic environment to induce the expression of HIF-1α. The cells SUP-B15 and RS4;11 of the hypoxia mimic group were lower sensitivity to VCR as compared with the control group; the apoptosis rate of the hypoxia mimic group was lower than that of the control group after 80 nmol/L VCR treatment. The expression levels of BAX protein and mRNA in the hypoxia mimic group were lower than those of the control group, and there was no significant difference in the expression levels of Bcl-2 protein between two groups.@*CONCLUSION@#Under hypoxic conditions, HIF-1α may mediate VCR resistance in B-ALL cells by downregulating the pro-apoptotic protein BAX.

Research on the mechanism of hypoxia promoting the migration of lung adenocarcinoma A549 cells / 中国应用生理学杂志

Objective: To investigate the mechanism that hypoxia promotes the migration of lung adenocarcinoma A549 cells. Methods: A549 cells were cultured and cells that knockdown of acetyl-CoA carboxylase 1 (ACC1) were obtained by transfection with lentivirus, and cells that knockdown of sterol regulatory element-binding proteins-1 (SREBP-1) were obtained by treated with si-RNA. A549 cells were treated with hypoxia combined with hypoxia inducible factor-1α (HIF-1α) inhibitor PX-478 (25 μmol); Hypoxia combined with linoleic acid (LA) (20 μmol) treated A549 cells with ACC1 knockdown, and A549 cells with SREBP-1 knockdown were treated by hypoxia. Transwell migration assay was used to detect cell migration. Western blot was conducted to detect HIF-1α, ACC1 and epithelial mesenchymal transition (EMT) related proteins, Vimentin, E-Cadherin and SREBP-1; Real-time fluorescent quantitative polymerase chain reaction (RT-qPCR) was performed to detect the changes of ACC1 and SREBP-1 mRNA in A549 cells after hypoxia and HIF-1α inhibitor PX-478 (25 μmol) treatment. Each experiment was repeated three times. Results: Compared with the normoxic control group, hypoxia promoted the migration of A549 cells (P＜0.01), and up-regulated the expressions of ACC1, HIF-1α (all P＜0.01) and SREBP-1 (P＜0.05). PX-478 (25 μmol) inhibited the migration of A549 cells induced by hypoxia and down-regulated the expression of SREBP-1 (all P＜0.05). ACC1 mRNA and SREBP-1 mRNA levels were increased after hypoxia treatment of A549 cells (all P＜0.05). The levels of ACC1 mRNA and SREBP-1 mRNA were decreased after A549 cells treated with hypoxia combined with PX-478 (25 μmol) for 24 h (P＜0.05, P＜0.01). Knockdown of SREBP-1 in A549 cells was obtained by transfection with si-RNA. Transwell migration assay showed the number of cell migration in si-SREBP-1 group was less than that in normoxia control group (P＜0.01). The si-SREBP-1 group and the si-NC group were treated with hypoxia. Compared with the control group, the number of cell migration in the si-SREBP-1 group was decreased (P＜0.01), however, the difference was not statistically significant compared with the normoxia si-SREBP-1 group (P＞0.05). Western blot showed that the expression of ACC1 in the si-SREBP-1 group was lower than that in the control group (P＜0.01). Compared with the control group, the expression of ACC1 was decreased after si-SREBP-1 group treated with hypoxia (P＜0.01). Knockdown of ACC1 inhibited the migration of A549 cells (P＜0.05). After knockdown of ACC1, the migration number of A549 cells under normoxia and 5% O2 conditions had no significant difference (P＞0.05). Application of LA under hypoxia condition rescued ACC1-knockdown induced inhibitory effect on hypoxia-promoted A549 cell migration (P＜0.05). Conclusion: Hypoxia promotes migration of lung adenocarcinoma A549 cells by regulating fatty acid metabolism through HIF-1α/SREBP-1/ACC1 pathway.

Establishment of a hypobaric hypoxia-induced cell injury model in PC12 cells / 浙江大学学报·医学版

To construct a hypobaric hypoxia-induced cell injury model. Rat pheochromocytoma PC12 cells were randomly divided into control group, normobaric hypoxia group and hypobaric hypoxia group. The cells in control group were cultured at normal condition, while cells in other two groups were cultured in normobaric hypoxia and hypobaric hypoxia conditions, respectively. CCK-8 method was used to detect cell viability to determine the optimal modeling conditions like the oxygen concentration, atmospheric pressure and low-pressure hypoxia time. The contents of lactate dehydrogenase (LDH), superoxide dismutase (SOD) and malondialdehyde (MDA) were detected by microplate method. The apoptosis ratio and cell cycle were analyzed by flow cytometry. The hypobaric hypoxia-induced cell injury model can be established by culturing for 24 h at 1% oxygen concentration and 41 kPa atmospheric pressure. Compared with the control group and normobaric hypoxia group, the activity of LDH and the content of MDA in hypobaric hypoxia group were significantly increased, the activity of SOD was decreased, the percentage of apoptosis was increased (all <0.05), and the cell cycle was arrested in G0/G1 phase. A stable and reliable cell injury model induced by hypobaric hypoxia has been established with PC12 cells, which provides a suitable cell model for the experimental study on nerve injury induced by hypoxia at high altitude.

Effects of intermittent hypoxia stimulation with different frequencies on HT22 cell viability and expression of Hif-1α and p-NF-κB / 生理学报

Intermittent hypoxia (IH) could induce cognitive impairment through oxidative stress and inflammation. However, the degree of cell damage is closely related to the IH stimulus frequency. IH stimulation with different frequencies also induces opposite results on neuronal cell lines. Therefore, this study was aimed to compare the effects of IH stimulation with three different frequencies on murine hippocampal neuronal HT22 cell activity, and to explore the molecular mechanism of the IH stimulus frequency-related neuron injury. HT22 cells were cultured and divided into control group and three IH stimulation groups with different frequencies. Oxygen concentration in the chamber was circulated between 21% and 1% (IH1 group, 6 cycles/h; IH2 group, 2 cycles/h; IH3 group, 0.6 cycle/h). Cell morphology was observed at 6, 12, 24 and 48 h of IH treatment. Cell viability was determined by the CCK-8 kit, lactate dehydrogenase (LDH) content in cell supernatant was determined by LDH kit, oxidative stress level was detected by the reactive oxygen species (ROS) probe, and protein expression levels of hypoxia inducible factor-1α (Hif-1α) and phosphorylated nuclear factor κB (p-NF-κB) were detected by Western blot. The results showed that, compared with control group, cell number and activity in the three IH groups were decreased, LDH content and ROS levels were increased with the prolongation of IH stimulation time, and the changes were most obvious in the IH1 group among those of the three IH groups. Hif-1α expression and the p-NF-κB/NF-κB ratio were also up-regulated with the prolongation of IH stimulation time, and the changes of IH1 group were the most significant. These results suggest that IH stimulation induces oxidative stress injury in HT22 cells, which is related to increased Hif-1α expression and NF-κB phosphorylation. Moreover, the higher frequency of IH stimulation induces more serious cell injury.

Research progress on in vitro models of cardiomyocyte injury / 中国中药杂志

Cardiovascular diseases seriously endanger human health and life. The accompanying myocardial injury has been a focus of attention in society. Chinese medicine,serving as a natural and precious reservoir for the research and development of new drugs,is advantageous in resisting myocardial injury due to its multi-component,multi-pathway,and multi-target characteristics. In recent years,with the extensive application of culture method for isolated cardiomyocytes,a cost-effective,controllable in vitro model of cardiomyocyte injury with uniform samples is becoming a key tool for mechanism research on cardiomyocyte injury and drug development.A good in vitro model can reduce experimental and manpower cost,and also accurately stimulate clinical changes to reveal the mechanism. Therefore,the selection and establishment of in vitro model are crucial for the in-depth research. This study summarized the modeling principles,evaluation indicators,and application of more than ten models reflecting different clinical conditions,such as injuries induced by hypoxia-reoxygenation,hypertrophy,oxidative stress,inflammation,internal environmental disturbance,and toxicity. Furthermore,we analyzed advantages and technical difficulties,aiming to provide a reference for in-depth research on myocardial injury mechanism and drug development.

Research progress in building and applying cardiomyocytes injury model / 中南大学学报(医学版)

Cardiomyocytes injury model has been widely used in the study for the molecular mechanism of cardiovascular diseases and drug action. It is very important to select the appropriate model due to the different formation mechanisms for various models. Clinical cardiovascular pathological change is relatively complex. Currently used models according to the characteristics of clinical cardiovascular diseases mainly include hydrogen peroxide-induced myocardial cell damage model, hypoxia reoxygenation injury model, adriamycin-induced myocardial cell damage model, high sugar high fat-induced myocardial cell damage model, and isoprenaline-induced myocardial cell damage model. Every model has its advantages as well as its disadvantages. The suitable model of myocardial cell injury can be selected according to the research purpose.

Periostin inhibits hypoxia-induced oxidative stress and apoptosis in human periodontal ligament fibroblasts p38 MAPK signaling pathway / 浙江大学学报·医学版

OBJECTIVE@#To investigate the effect of periostin on hypoxia-induced oxidative stress and apoptosis in human periodontal ligament fibroblasts and the molecular mechanism involved.@*METHODS@# cultured human periodontal ligament fibroblasts were placed in an anaerobic gas-producing bag for hypoxia treatment for 48 h followed by treatment with periostin at low (25 ng/mL), moderate (50 ng/mL) or high (100 ng/mL) doses. MTT assay was used to measure the cell viability, and the cell apoptosis rate was determined using flow cytometry. The contents of IL-1β, IL-6 and TNF-α in the cells were determined with ELISA, and ROS levels were measured using a fluorescent plate reader. The intracellular SOD activity was detected using ELISA. The expressions of HIF-1α, P21, cyclin D1, Bax, cleaved caspase-3, Bcl-2, P38MAPK and p-p38 MAPK proteins in the cells were detected with Western blotting.@*RESULTS@#Hypoxia treatment significantly reduced the cell viability ( < 0.05), increased P21, Bax, and cleaved caspase-3 protein levels ( < 0.05), promoted cell apoptosis ( < 0.05), and decreased cyclin D1 and Bcl-2 protein levels ( < 0.05) in the cells. Compared with the hypoxic group, the cells treated with periostin at different concentrations showed significantly increased cell viability ( < 0.05) with significantly lowered apoptotic rates ( < 0.05) and decreased expression levels of Bax and cleaved caspase-3 ( < 0.05) but significantly increased expression levels of cyclin D1 and Bcl-2 ( < 0.05). Hypoxic exposure of the cells resulted in significantly increased expression levels of HIF-1α and p-p38 MAPK ( < 0.05) and increased levels of IL-1β, IL-6, TNF-α and ROS ( < 0.05) but decreased SOD activity ( < 0.05). Periostin treatment at different concentrations significantly lowered the expression levels of HIF-1α and p-p38 MAPK ( < 0.05) and the levels of IL-1β, IL-6, TNF-α and ROS ( < 0.05) and significantly increased SOD activity in the hypoxic cells ( < 0.05).@*CONCLUSIONS@#Periostin promotes the proliferation, inhibits apoptosis, enhances cellular antioxidant capacity, and reduces inflammatory damage in human periodontal ligament fibroblasts exposed to hypoxia possibly by inhibiting the activation of the p38 MAPK signaling pathway.

Salvianolic acid B regulates mitochondrial autophagy mediated by NIX to protect H9c2 cardiomyocytes from hypoxia/reoxygenation injury / 中国中药杂志

The aim of this paper was to investigate whether the mechanism of salvianolic acid B in protecting H9 c2 cardiomyocytes from hypoxia/reoxygenation injury is related to the regulation of mitochondrial autophagy mediated by NIX. H9 c2 cardiomyocytes were cultured in vitro and divided into normal group, model group and salvianolic acid B group(50 μmol·L~(-1)). Hypoxia/reoxygenation injury model was established by hypoxia for 4 h and reoxygenation for 2 h. In normal group, high glucose DMEM medium was used for culture. Those in model group were cultured with DMEM medium without glucose and oxygen, and no drugs for hypoxia and reoxyge-nation. In salvianolic acid B group, salvianolic acid B prepared by glucose-free DMEM medium was added during hypoxia, and the other process was as same as the model group. The cell viability was evaluated by CCK-8 assay. The leakage of lactate dehydrogenase(LDH) was detected by microplate method. The levels of intracellular reactive oxygen species(ROS) and mitochondrial membrane potential(ΔΨm) were measured by chemical fluorescence method. The level of intracellular adenosine triphosphate(ATP) was mea-sured by fluorescein enzyme method. The autophagy related proteins LC3-Ⅰ, LC3-Ⅱ, apoptosis related protein cleaved caspase-3 and mitochondrial autophagy receptor protein NIX were detected by Western blot. As compared with the normal group, the activity of H9 c2 cardiomyocytes and ATP level were decreased(P<0.05); LDH leakage and ROS production were increased(P<0.01); ΔΨm was decreased(P<0.01); LC3-Ⅱ/LC3-Ⅰ ratio, cleaved caspase-3 and NIX protein expression levels were increased(all P<0.05) in the model group. As compared with the model group, the activity of cells and ΔΨm were significantly increased(P<0.01); ATP level was increased(P<0.05); LDH leakage and ROS generation were decreased(P<0.01); LC3-Ⅱ/LC3-Ⅰ ratio was decreased(P<0.01); cleaved caspase-3 and NIX expression levels were decreased(P<0.05) in the salvianolic acid B group. The protective effect of salvianolic acid B on hypoxia/reoxygenation injury of H9 c2 cardiomyocytes may be associated with inhibiting mitochondrial auto-phagy. The specific mechanism may be related to inhibiting the activation of mitochondrial autophagy mediated by NIX, increasing ΔΨm, reducing ROS production, reducing the expression of cleaved caspase-3, LC3-Ⅱ, and increasing cell viability.

Propofol protects human cardiac AC16 cells from CoCl2-induced hypoxic injury / 中南大学学报(医学版)

To explore the effect of propofol on human cardiac AC16 cells under CoCl2-induced hypoxic injury and the possible mechanisms.
 Methods: Human AC16 cardiomyocytes were treated with cobalt chloride (CoCl2) to mimic hypoxic condition in cultured cardiomyocytes. The AC16 cells were divided into 3 groups: a control group, a CoCl2 hypoxia group (CoCl2 group), and a propofol+CoCl2 group (propofol+ CoCl2 group). The cell viability was assessed by cell counting kit-8 (CCK-8). Cell apoptosis ratio (AR) and the mitochondrial membrane potential (Δψm) were detected by flow cytometry. The reactive oxygen species (ROS) production in AC16 cells were determined with the ROS-sensitive fluorescent probe. Meanwhile, total intracellular levels of malondialdehyde (MDA) and superoxide dismutase (SOD) in AC16 cells were detected with commercially available kits. Western blot was used to evaluate the activation of c-Jun N-terminal kinase (JNK) and p38 signaling pathways.
 Results: 1) Compared with the control group, AC16 cell viability was decreased significantly in the CoCl2 group following the treatment with 500 μmol/L CoCl2 (P<0.01); 2) Compared with the control group, AR value in AC16 cells was increased significantly in the CoCl2 group, while Δψm was decreased significantly (all P<0.01). Compared with the CoCl2 group, AR value in AC16 cells was decreased significantly in the propofol+CoCl2 group, while Δψm was increased significantly (both P<0.05); 3) Compared with the control group, the levels of ROS and MDA were increased significantly, and the level of SOD was significantly decreased in the CoCl2 group (all P<0.01). Compared with the CoCl2 group, the ROS and MDA levels in the propofol+CoCl2 group were increased significantly and the SOD levels were decreased significantly (all P<0.05); 4) Compared with the control group, the phosphorylation levels of JNK and p38 were increased significantly (both P<0.05) in the CoCl2 group. Compared with the CoCl2 group, the phosphorylation levels of JNK and p38 were decreased significantly in the propofol+CoCl2 group (both P<0.05).
 Conclusion: The pretreatment with propofol may protect human cardiac AC16 cells from the chemical hypoxia-induced injury through regulation of JNK and p38 signaling pathways.

Effect of miR-873 on cardiomyocyte apoptosis induced by hypoxia reoxygenation and its mechanism / 中南大学学报(医学版)

To explore the role of miR-873 in cardiomyocyte injury induces by hypoxia reoxygenation (H/R) and its related mechanisms.
 Methods: H/R model was established by culturing mouse cardiac H9c2 cells in vitro, and miR-873 mimic was transfected. The experiments were divided into a control group, a H/R group, a negative control group and a miR-873 mimic group. The expression of miR-873 was measured using real-time PCR. The protein expression levels of egl-9 family hypoxia inducible factor 3 (Egln3), B-cell lymphoma-2 (Bcl-2) and Bcl-2 associated X protein (Bax) were evaluated by Western blotting. Cell apoptosis ELISA kit and cysteine-containing, aspartate-specific proteases-3 (caspase-3) activity kit was used to detect cell apoptosis and caspase-3 activity, respectively. The targeting effect of miR-873 on Egln3 were examined by the dual luciferase report gene assay, and the experiments were divided into a negative control group, a Egln3 3'-untranslated regions (3'-UTR) WT group (WT group) and a Egln3 3'-UTR MUT group (MUT group). In order to further detect the effects of Egln3 on miR-873 mimics, the Egln3 overexpressed cells were constructed, and the experiments were divided into a H/R group, a H/R+miR-873 mimic group, a H/R+pcDNA3-Egln3 (pcEgln3) group and a H/R+ miR-873 mimic+pcEgln3 group.
 Results: Compared with the control group, the expression level of miR-873 was significantly decreased in the H/R group (P0.05). In the over-expression experiment, compared with the H/R group, the cell apoptosis and the ratio of Bax/Bcl-2 were significantly reduced in the miR-873 mimic group (both P<0.05). Compared with miR-873 mimic group, the cell apoptosis and the ratio of Bax/Bcl-2 were significantly up-regulated in the H/R+pcEgln3 group and the H/R+miR-873 mimic+pcEgln3 group (all P<0.05).
 Conclusion: MiR-873 can inhibit H/R- induced apoptosis of cardiomyocyte via targeting Egln3.

Airway epithelial cells increase macrophage chemotaxis and inflammatory cytokine secretion under hypoxic conditions / 中南大学学报(医学版)

To investigate the effects of airway epithelial cells on macrophages chemotaxis and inflammatory cytokine expression under hypoxic conditions.
 Methods: Human bronchial epithelial cells (HBE) treated with different concentrations (0, 100, 200, 400, 800 μmol/L) of CoCl2 or transfected with HIF-1α siRNA were co-cultured with THP-1-derived M1 macrophages or M2 macrophages. The chemotactic effects on macrophages were analyzed by Transwell assay. The levels of TNF-α, IFN-γ, IL-4, IL-13 and IL-10 in the supernatants of macrophages were detected by ELISA, and HIF-1α or Cav-1 mRNA expression in HBE or macrophages was detected by RT-qPCR.
 Results: HBE cells promoted macrophages chemotaxis in a time- and concentration-dependent manner. Compared to un-transfected group, the chemotactic ability of HBE transfected with HIF-1α siRNA was significantly weakened (P<0.01). Under the same culture conditions, the chemotaxis of M2 macrophages was greater than that in THP1-derived M1 macrophages. The concentrations of TNF-α, IFN-γ, IL-4, IL-13 and IL-10 in the supernatants of macrophages were increased in a time-and concentration-dependent manner. The concentrations of TNF-α and IFN-γ were increased further after co-culturing for 8 and 12 h; while IL-4, IL-13 and IL-10 concentrations were increased further during 24 h of co-culture. The levels of cytokines in the supernatants of macrophages co-cultured with HBE and transfected with HIF-1α siRNA were significantly lower than those in un-transfected cells (P<0.05 or P<0.01). The reduction of TNF-α or IFN-γ was more obvious. The expression of HIF-1α or Cav-1 mRNA in HBE or macrophages was increased in a concentration-dependent manner after 8 or 12 h co-culture, which was significantly reduced when HBE was transfected with HIF-1α siRNA.
 Conclusion: Airway epithelial cells can enhance macrophages chemotaxis and pro-inflammatory cytokines expressions under hypoxic condition. HIF-1α and Cav-1 may be the important mediators in these processes.

Modulation of drug-metabolizing enzymes and transporters under hypoxia environment / 生理学报

Drug metabolism is significantly affected under hypoxia environment with changes of pharmacokinetics, expression and function of drug-metabolizing enzymes and transporters. Studies have shown that hypoxia increases the release of a series of inflammatory cytokines which can modulate drug metabolism. Besides, both hypoxia inducible factor 1α (HIF-1α) and microRNA-mediated pathways play a role in regulating drug metabolism. This article reviewed the impact and single-factor modulating mechanisms of drug metabolism under hypoxia, and put forward the speculation and prospects of multi-factor modulating mechanisms.

Extracts of Celastrus Orbiculatus Inhibit Cancer Metastasis by Down-regulating Epithelial-Mesenchymal Transition in Hypoxia-Induced Human Hepatocellular Carcinoma Cells / 中国结合医学杂志

OBJECTIVE@#To evaluate the effects of Celastrus Orbiculatus extracts (COE) on metastasis in hypoxia-induced hepatocellular carcinoma cells (HepG2) and to explore the underlying molecular mechanisms.@*METHODS@#The effect of COE (160, 200 and 240 µ g/mL) on cell viability, scratch-wound, invasion and migration were studied by 3-4,5-dimethyl-2-thiazolyl-2,5-diphenyl-2-H-tetrazolium bromide (MTT), scratch-wound and transwell assays, respectively. CoCl was used to establish a hypoxia model in vitro. Effects of COE on the expressions of E-cadherin, vimentin and N-cadherin were investigated with Western blot and immunofluorescence analysis, respectively.@*RESULTS@#COE inhibited proliferation and metastasis of hypoxia-induced hepatocellular carcinoma cells in a dose-dependent manner (P<0.01). Furthermore, the expression of epithelial-mesenchymal transition (EMT) related markers were also remarkably suppressed in a dose-dependent manner (P<0.01). In addition, the upstream signaling pathways, including the hypoxia-inducible factor 1 α (Hif-1 α) and Twist1 were suppressed by COE. Additionally, the Hif-1 α inhibitor 3-5'-hydroxymethyl-2'-furyl)-1-benzylindazole (YC-1), potently suppressed cell invasion and migration as well as expression of EMT in hypoxia-induced HepG2 cells. Similarly, the combined treatment with COE and YC-1 showed a synergistic effect (P<0.01) compared with the treatment with COE or YC-1 alone in hypoxia-induced HepG2 cells.@*CONCLUSIONS@#COE significantly inhibited the tumor metastasis and EMT by suppressing Hif-1 α/Twist1 signaling pathway in hypoxia-induced HepG2 cell. Thus, COE might have potential effect to inhibit the progression of HepG2 in the context of tumor hypoxia.

Effects of Notch signal on the expressions of HIF-α and autophagy- related genes Beclin1, LC3I, LC3II in oxygen-glucose deprivation induced myocardial cell injury / 中国应用生理学杂志

OBJECTIVE@#To investigate the effects of Notch signal on hypoxic induction factor (HIF-1α) and autophagy-associated genes Beclin1, LC3I, LC3II in oxygen-glucose deprivation (OGD) induced myocardial cell injury.@*METHODS@#The OGD model was established using hypoxic culture box and hypoglycemic DMEM medium. The cells were divided into normal control group, OGD group, OGD + NC siRNA group, OGD + Notch1 siRNA group and OGD + HIF-1α siRNA group. Western blot was used to detect the interference effects of HIF-1α siRNA and Notch1 siRNA. The effects of Notch1 siRNA and HIF-1α siRNA on the activity of myocardial cells in OGD model were detected by the CCK-8 assay. The effects of Notch1 siRNA and HIF-1α siRNA on autophage-associated genes Beclin1, LC3I and LC3II expression were detected by Western blot.@*RESULTS@#The results of Western blot showed that HIF-1α siRNA could effectively knock down the expression of HIF-1α in myocardial cells in OGD model, and Notch1 siRNA could effectively knock down the expression of Notch1 and HIF-1α in myocardial cells in OGD model. The result of CCK-8 assay showed that Notch1 siRNA and HIF-1α siRNA reduced the activity of myocardial cells in OGD model, and there was no statistical difference between the two groups. Western blot results showed that Notch1 siRNA and HIF-1α siRNA could reduce the expressions of the autophagy-associated genes Beclin1, LC3I and LC3II, and reduce the ratio of LC3II to LC3I at mRNA level.@*CONCLUSION@#Notch1 plays a role in myocardial protection by regulating the expression of HIF-1α to regulate the autophagy in OGD model cells.

Effects of Vitamin D Receptor on Mucosal Barrier Proteins in Colon Cells under Hypoxic Environment / 中国医学科学院学报

To investigate the expressions of mucosal barrier proteins in colon cell line DLD-1 under hypoxic environment and its mechanism. Methods After DLD-1 cells were treated separately with hypoxia(l% O),vitamin D(100 nmol/L),or vitamin D plus hypoxia for 48 hours,the expressions of vitamin D receptor(VDR),tight junction proteins zonula occludens-1(ZO-1),occludin,Claudin-1,and adherent junction protein(E-cadherin)were determined by Western blot.Stable VDR knock-down(Sh-VDR)DLD-1 cell line and control DLD-1 cell line were established by lentivirus package technology and the protein expressions after hypoxia treatment were detected. Results Compared with control group,the expressions of occludin,Claudin-1,and VDR increased significantly after hypoxia treatment(all <0.001).In addition to the protein expressions of occludin,Claudin-1 and VDR,the expressions of ZO-1 and E-cadherin were also obviously higher in vitamin D plus hypoxia group than in single vitamin D treatment group(all <0.001).After hypoxia treatment,Sh-VDR cell line showed significantly decreased expressions of ZO-1(<0.001),occludin(<0.05),Claudin-1(<0.01)and E-cadherin(<0.001)when compared with untreated Sh-VDR cell line. Conclusion VDR acts as a regulator for the expressions of intestinal mucosal barrier proteins under hypoxia environment in DLD-1 colon cell line,indicating that VDR pathway may be another important protective mechanism for gut barrier in low-oxygen environment.

Effect of ultraviolet irradiation on the proliferation of acute promyelocytic leukemia cells under hypoxic conditions and related mechanisms / 中国当代儿科杂志

OBJECTIVE@#To study the effect of 280 nm-LED ultraviolet irradiation on the proliferation of acute promyelocytic leukemia (APL) HL-60 cells under hypoxic conditions and related mechanism.@*METHODS@#HL-60 cells in the logarithmic growth phase were selected and divided into control, hypoxia, ultraviolet and hypoxia+ultraviolet groups. The cells in the hypoxia group were treated with cobalt chloride (with a final concentration of 150 μmol/L), those in the ultraviolet group were irradiated by 280 nm-LED ultraviolet with an energy intensity of 30 J/m, and those in the hypoxia+ultraviolet group were treated with cobalt chloride and then irradiated by 280 nm-LED ultraviolet. After 48 hours of treatment, the cells were placed under an invert microscope to observe cell morphology. CCK-8 assay was used to measure the inhibition rate of cell proliferation. Annexin V-FITC/PI double staining flow cytometry was used to evaluate cell apoptosis. Quantitative real-time PCR was used to measure the mRNA expression of Bcl-2. Each experiment above was repeated three times independently.@*RESULTS@#Compared with the control group, the experimental groups showed shrinkage, decreased brightness, and disordered arrangement of cells, and the number of cells decreased over the time of culture. There were significant differences in the inhibition rate of cell proliferation and cell apoptosis rate among the groups (P<0.01), and the hypoxia+ultraviolet group showed the strongest inhibition of cell proliferation and induction of cell apoptosis, followed by the ultraviolet group and the hypoxia group. Compared with the control group, the other three groups had a gradual reduction in the mRNA expression of Bcl-2, and the hypoxia+ultraviolet group had a significantly greater reduction than the hypoxia and ultraviolet groups (P<0.01).@*CONCLUSIONS@#Both hypoxia and ultraviolet irradiation can inhibit the proliferation of HL-60 cells and induce cell apoptosis, and ultraviolet irradiation has a better effect on proliferation inhibition and cell apoptosis under hypoxic conditions than under normoxic conditions, possibly by downregulating the mRNA expression of Bcl-2.

Inhibiting miR-186 expression alleviates mitochondrial damage in hypoxic human umbilical vein endothelial cells / 南方医科大学学报

OBJECTIVE@#To investigate the effect of miR-186 inhibition on the expression of hypoxia-inducible factor-1α (HIF-α) and mitochondrial function in hypoxic vascular endothelial cells.@*METHODS@#Human umbilical vein endothelial cells (HUVECs) cultured in routine or hypoxic conditions for 6 h were examined for the expression of miR-186. A miR-186 inhibitor was transfected in the HUVECs, and the cells were subsequently cultured in hypoxic condition for 6 h to observe the changes in the mitochondrial structure under an electron microscope. The changes in the mRNA and protein expressions of HIF-1α in response to miR-186 interference were tested using real-time fluorescent quantitative PCR and Western blotting.@*RESULTS@#The expression of miR-18 was mildly increased in HUVECs after hypoxic exposure for 6 h (=0.0188). Interference of miR-186 expression obviously promoted the mRNA and protein expressions of HIF-1α in HUVECs. In hypoxic conditions, miR-186 interference significantly reduced mitochondrial damage in HUVECs as observed under electron microscope (=0.0297).@*CONCLUSIONS@#Inhibition of miR-186 protects vascular endothelial cells against hypoxic injuries by promoting HIF-α expression to lessen mitochondrial damage, suggesting the possibility of targeted miR-186 interference for treatment of hemorrhagic shock.

Astragaloside Ⅳ regulates Nrf2/Bach1/HO-1 signaling pathway and inhibits H9c2 cardiomyocyte injury induced by hypoxia-reoxygenation / 中国中药杂志

Astragaloside Ⅳ(AS-Ⅳ) has protective effects against ischemia-reperfusion injury(IRI), but its mechanism of action has not yet been determined. This study aims to investigate the protective effects and mechanism of AS-Ⅳ on H9c2 cardiomyocyte injury induced by hypoxia-reoxygenation(H/R). The H/R model of myocardial cells was established by hypoxic culture for 12 hours and then reoxygenation culture for 8 hours. After AS-Ⅳ treatment, cell viability, the reactive oxygen species(ROS) levels, as well as the content or activity of superoxide dismutase(SOD), malondialdehyde(MDA), interleukin 6(IL-6), and tumor necrosis factor alpha(TNF-α), were measured to evaluate the effect of AS-Ⅳ treatment. The effect of AS-Ⅳ on HO-1 protein expression and nuclear Nrf2 and Bach1 protein expression was determined by Western blot. Finally, siRNA was used to knock down HO-1 gene expression to observe its reversal effect on AS-Ⅳ intervention. The results showed that as compared with the H/R model group, the cell viability was significantly increased(P<0.01), ROS level in the cells, MDA, hs-CRP and TNF-α in cell supernatant and nuclear protein Bach1 expression in the cells were significantly decreased(P<0.01), while SOD content, HO-1 protein expression in cells and expression of nuclear protein Nrf2 were significantly increased(P<0.01) in H/R+AS-Ⅳ group. However, pre-transfection of HO-1 siRNA into H9c2 cells by liposome could partly reverse the above effects of AS-Ⅳ after knocking down the expression of HO-1. This study suggests that AS-Ⅳ has significant protective effect on H/R injury of H9c2 cardiomyocytes, and Nrf2/Bach1/HO-1 signaling pathway may be a key signaling pathway for the effect.