Objective To investigate relationship between hypoxia microenvironment and occurrence and development of hepatocellular carcinoma (HCC). Method The relevant literatures on researches of the relationship between the hypoxic microenvironment and the HCC were review and analyzed. Results The hypoxia microenvironment played an important role in inducing the drug resistance and angiogenesis of the HCC cells, and it was an important factor of affecting the ability of tumor metabolism, invasion, and migration. The hypoxia microenvironment could up-regulate the expression of hypoxia-inducible factors (HIFs) and promote its transcriptional activity, promote the expression of the vascular endothelial growth factor gene, and regulate the neovascularization in the tumor. Among them, the HIF-1α played a major role in regulating the angiogenesis, immune escape, tumor invasion and metastasis-related gene expression, participating in the glycolysis, regulating lysyl oxidase 2 and thus regulated epithelial-mesenchymal transition, then promoted the invasion and metastasis of the HCC; HIF-2α was a key regulator of the malignant phenotype involving in the cell proliferation, angiogenesis, apoptosis, metabolism, metastasis, and resistance to chemotherapy. The hypoxia microenvironment posed some difficulties for the treatment of HCC, but it was also a potential therapeutic breakthrough. Conclusion Hypoxia microenvironment can promote invasion and metastasis of HCC through various mechanisms, which provides new targets and strategies for clinical treatment of HCC.
ObjectiveTo summarize the application status of hypoxia mimetic agents in bone tissue engineering.MethodsThe related literature about the hypoxia mimetic agents in bone tissue engineering was reviewed and analyzed. And the application status and progress of hypoxia mimetic agents in bone tissue engineering were retrospectively analyzed.ResultsHypoxia mimetic agents have the same effect as hypoxia in up-regulating the level of hypoxia inducible factor 1α (HIF-1α). The combination of hypoxia mimetic agents and scaffolds can up-regulate the level of HIF-1α in bone tissue engineering, thus promoting early vascularization and bone regeneration of the bone defect area, which provides a new idea for using bone tissue engineering to repair bone defect. At present, the commonly used hypoxia mimetic agents include iron chelating agents, oxoglutarate competitive analogues, proline hydroxylase inhibitors, etc.ConclusionHypoxia mimetic agents have a wide application prospect in bone tissue engineering, but they have been used in bone tissue engineering for a short time, more attention should be paid to their possible side effects. In the future research, the hypoxia mimetic agents should be developed in the direction of higher targeting specificity and safety, and the exact mechanism of hypoxia mimetic agents in promoting bone regeneration should be further explored.
ObjectiveTo explore the effect of five copies hypoxia-responsive element (5HRE) and carcinoembryonic antigen promoter (CEAp) element, and to explore the inhibition effect of lentiviral vectors targeted Ras association domain family 1 isoform A (RASSF1A) gene on SGC7901 human gastric cancer cells. Methods①Expressions of carcinoembryonic antigen (CEA) mRNA and its protein, and RASSF1A protein in SGC7901, MKN28, and MCF-10A cells were detect by real time-PCR (qRT-PCR), immunocytochemistry, and Western blot, to confirm the experimental and negative control cells.②The recombinant vectors of pGL4.20-5HRE-CEAp-Luc were constructed through molecular cloning technique to transfected SGC7901, MKN28, and MCF-10A cells. Each kind of cell was divided into 2 groups:one of them didn't add CoCl2 (normoxia group), and another group added CoCl2 (hypoxia group). Comparison of the fold of activation was performed.③SGC7901 cells were infected by lentiviral vectors of pLV-5HRE-CEAp-RASSF1A (infection group) and negative virus (negative control group), SGC7901 cells without any treatment as blank control group. Then SGC7901 cells of 3 groups were divided into 2 groups:one of them didn't add CoCl2 (normoxia group), and another group added CoCl2 (hypoxia group). The expression of RASSF1A protein was tested by Western blot, and the growth inhibition rate was confirmed by cell counting kit-8 (CCK-8) assay. Comparisons of expression of RASSF1A protein and growth inhibition rate of each group were performed. Results①Results of qRT-PCR, immunocytochemistry and Western blot showed that, SGC7901 cells showed higher expression of CEA mRNA and positive expression of RASSF1A protein than corresponding index of MKN28 cells and MCF-10A cells (P < 0.05), which were assigned as experimental cells; but MKN28 cells showed lower expression of CEA mRNA and negative expression of RASSF1A protein, which were assigned as negative control cells.②In SGC7901 and MKN28 cells transfected recombinant vectors of pGL4.20-5HRECEAp-Luc, compared with normoxia group in the same kind of cell group, the folds of activation in hypoxia group were higher (P < 0.01), but there was no significant difference between the normoxia group and hypoxia group in MCF-10A cells (P > 0.05). In the condition of with or without CoCl2, compared with SGC7901 cells in the same condition, the folds of activation in MCF-10A and MKN28 cells were both lower (P < 0.05); compared with MKN28 cells, the fold of activation in MCF-10A cells was lower (P < 0.05).③Western blot results showed that, in the condition with and without CoCl2, expressions of RASSF1A protein decreased in SGC7901 cells of blank control group and negative control group; weak expressions of RASSF1A protein was observed in SGC7901 cells of infection group when in condition of without CoCl2, but increased when adding CoCl2. But RASSF1A protein didn't expressed in MKN28 cells of blank control group, negative control group, and infection group, whether adding CoCl2 or not. CCK-8 assay result showed that, in SGC7901 cells, the growth inhibition rate of infection group which added CoCl2 was higher than those of other 5 groups (P < 0.05); in MKN28 cells, the growth inhibition rates of infection group and negative group were all higher than those of blank control group, whether adding CoCl2 or not (P < 0.05), but there was no significant difference among the infection group and negative group, whether adding CoCl2 or not (P > 0.05). ConclusionsA new hypoxia inducible and cea-positive tumor-targeting transcriptional regulatory element of 5HRE-CEAp is established successfully, and lentivirus vector of pLV-5HRE-CEAp-RASSF1A can significant inhibit the growth of SGC7901 cells under hypoxia condition.
Objective To investigate the changes in mitochondrial morphology, structure and function in rats with severe intermittent hypoxia, as well as the effects of intermittent hypoxia and its severity on cognitive function. Methods A total of 18 rats were selected to construct a model of severe intermittent hypoxia, which were divided into a normal control group, an intermittent air control group, and a 5% intermittent hypoxia group for 8 weeks, with 6 rats in each group. The structural and functional changes of mitochondria in the hippocampal CA1 region were observed. A total of 30 rats were randomly divided into 5 groups: a normal control group, an intermittent air control group, a 5% intermittent hypoxia 4-week group, a 5% intermittent hypoxia 6-week group, and a 5% intermittent hypoxia 8-week group, with 6 rats in each group. The cognitive function of the rats in each group was evaluated by Morris water maze experiment. Results In the mitochondria of the hippocampal CA1 region of severely intermittent hypoxic rats, bilayer membranes or multilayer membranes were visible, the mitochondria were swollen, cristae were broken and vacuolated, and their respiratory function was significantly weakened, the membrane permeability was increased, and the membrane potential was reduced. In the Morris water maze, there was no significant difference in swimming speed between the rats. With the prolongation of intermittent hypoxia action time, the latency of finding the hidden platform in each group of rats increased significantly, and the residence time of the target quadrant decreased significantly. Conclusions Mitochondrial structure in the hippocampal CA1 region of the rat brain is destroyed during severe intermittent hypoxia, and dysfunction and cognitive impairment occur. With the prolongation of intermittent hypoxic injury, the degree of cognitive impairment worsens.
With the surged prevalence of myopia, the pathogenic mechanism underlying myopia has attracted attention. At present, it is generally believed in the flied that the reduced blood perfusion in the choroid is crucial for myopigenesis. Then, in the process of myopigenesis, how are the blurred visual signals transmitted to the choroidal blood vessels through the retina and retinal pigment epithelium, leading to the reduced choroidal blood perfusion. The cellular and molecular mechanisms underpinning this process remain elusive. In recent years, the theory of scleral hypoxia has attracted much attention. Popular signaling molecules in current research include dopamine, epidermal growth factor, retinoic acid, cholinergic molecules and adenosine, etc. These factors are likely to participate in signal transduction in retina and RPE, thus causing changes in choroidal blood flow and affecting the occurrence and development of myopia. Therefore, these signaling factors and their downstream pathways may provide new ideas for the prevention and control of myopia targets.
Objective To study the effect of hypoxia on proliferation of cultured bovine retinal pigment epithelium (RPE) cells and expression of the antiapoptotic protein bcl-2. Methods The bovine RPE cells were cultured under normal and hypoxic chamber respectively. After 24 hours, the proliferation of RPE cells was evaluated by［3-(4,5-dimethylthiazole-2yl)-2,5-diphenyl tetrazolium bromide, MTT］test. At the same time, anti-bcl-2 protein antibody was examined by immuno-histochemistry method. Results The A value in the hypoxia group was higher than that in the normal group after 24 hours (P＜0.05 )in MTT-test. Positive staining for anti-bcl-2 protein antibody was seen in 72.6% cells in hypoxia group and 38.64% in normal group. The positive staining was more obvious near the nucleus, and fine granules scattered in cytoplasm of some cells. Conclusion Hypoxia can stimulate the proliferation of RPE cells and expression of antiapoptotic protein bcl-2. The results indicate that bcl-2 may play an important role in mediating the proliferation activity of RPE cells. (Chin J Ocul Fundus Dis, 2002, 18: 293-295)
Objective To study the correlation between smoking and obstructive sleep apnea (OSA). Methods A total of 454 patients from October 2015 to July 2021 were retrospectively collected for nocturnal polysomnography monitoring (no less than 7 hours). The patients were divided into an OSA group (n=405) and a control group (n=49, patients with primary snoring) according to the results of polysomnography monitoring. According to the apnea hypopnea index (AHI) and the lowest oxygen saturation during sleep, the severity of OSA was classified into a mild to moderate group (5 times/h ≤ AHI<30 times/h) and a severe group (AHI ≥30 times/h). The patients were inquired about their smoking history, then the patients diagnosed with OSA were further divided into a smoking group, a smoking cessation group, and a non-smoking group based on their smoking history. Results The smoking rate of the patients in the OSA group was higher than that in the control group (50.9% vs. 32.7%, P<0.05), while the smoking rate in the severe OSA group was higher than that in the mild to moderate group (55.7% vs. 39.8%, P<0.05). Smoking was positively correlated with AHI, cumulative percentages of time spent at oxygen saturation below 90% (Ts90%), and total apnea time (r value was 0.196, 0.197, 0.163, P<0.05), while negatively correlated with the lowest and average SpO2 during sleep (r value was –0.202, –0.214, P<0.05). The logistic regression analysis with severe OSA as the outcome variable showed that smoking (OR=1.781) and obesity (OR=1.930) were independent risk factors of severe OSA (P<0.05). The comparison between groups of the OSA patients with different smoking states showed that the proportion of severe OSA, AHI, Ts90%, and total apnea time (77.8%, 53.55 times/h, 18.35%, and 111.70 minutes, respectively) of the smoking group were higher than those of the non-smoking group (62.8%, 40.20 times/h, 8.40%, and 76.20 minutes, respectively, P<0.05). The lowest SpO2 and average SpO2 during sleep (69.50%, 93.00%, respectively) of the smoking group were lower than those of the non-smoking group (75.00%, 94.00%, respectively, both P<0.05). The average SpO2 of the smoking cessation group was higher than that of the smoking group (94.00% vs. 93.00%, P<0.05), and the Ts90% of the smoking cessation group was lower than that of the smoking group (6.75% vs. 18.35%, P<0.05). Conclusions Smoking significantly affects the degree of sleep-disordered breathing and may be an independent risk factor for severe OSA. Smoking can exacerbate the severity of OSA and the degree of hypoxia, while smoking cessation can improve the degree of hypoxia in OSA patients.
ObjectiveTo investigate the expression and correlation of hypoxia inducible factor 1α (HIF-1α) and autophagy related molecules (Beclin1 and LC3B) in rat nucleus pulposus cells under hypoxia in vitro.MethodsThe nucleus pulposus cells were extracted from the nucleus pulposus of healthy adult Sprague Dawley rats and passaged. The 3rd generation cells were identified by HE staining and collagenase type Ⅱ immunofluorescence staining and randomly divided into 4 groups. The cells in group A were cultured for 8 hours under normal oxygen condition (37℃, 5%CO2, 20%O2); the cells in group B were cultured for 8 hours under hypoxia condition (37℃, 5%CO2, 1%O2); the cells in group C were transfected with HIF-1α-small interfering RNA and cultured for 8 hours under hypoxia condition; and the cells in group D were cultured with autophagy inhibitor 3-MA for 8 hours under hypoxia condition. Western blot and real-time fluorescence quantitative PCR (qRT-PCR) were used to detect the expressions of HIF-1α and autophagy related molecules (Beclin1 and LC3B) in all groups.ResultsHE staining of the 3rd generation nucleus pulposus cells showed that the cytoplasm was light pink and the nucleus was blue black, and the collagenase type Ⅱ immunofluorescence staining was positive. Western blot and qRT-PCR results showed that the relative expressions of HIF-1α, Beclin1, and LC3B proteins and genes in group B were significantly higher than those in group A (P<0.05); the relative expressions of HIF-1α, Beclin1, and LC3B proteins and genes in group C were significantly lower than those in group B (P<0.05). There was no significant difference in the relative expression of HIF-1α protein and gene between groups B and D (P>0.05); while the relative expressions of Beclin1 and LC3B proteins and genes in group D were significant lower than those in group B (P<0.05).ConclusionHypoxia can induce the expressions of HIF-1α and autophagy related molecules (Beclin1 and LC3B) in rat nucleus pulposus cells, and HIF-1α in rat nucleus pulposus cells under hypoxia is related to the expression of autophagy related molecules, that is, down-regulation of HIF-1α can significantly reduce the expression of autophagy related molecules, while the down-regulation of autophagy levels under hypoxia has no or little effect on the expression of HIF-1α.
Hypoxic microenvironment always exists in solid tumors, and it closely relates to the development and metastasis of solid tumor. As a main transcription factor responding to hypoxic environment, hypoxia-inducible factor (HIF) can promote tumor cell proliferation, survival, angiogenesis, and epithelial-mesenchymal transition (EMT), etc. EMT is a biological process that epithelial phenotype was transformed into mesenchymal phenotype, which is mainly associated with its signaling pathways, transcription factors, inflammatory factors and miRNAs, and plays a vital role in tumor invasion and metastasis. This paper summarizes the effects of hypoxia signaling pathway, Wnt/β-catenin signaling pathway, Notch signaling pathway, NF-κB signaling pathway, Hedgehog (Hh) signaling pathway and PI3K/Akt signaling pathway on the EMT of tumor cells.
ObjectiveTo investigate the effects of hypoxia inducible factor 1α (HIF-1α) overexpression on the differentiation of stem cells derived from human exfoliated deciduous teeth (SHED) into vascular endothelial cells.MethodsSHED was isolated from the retained primary teeth donated by healthy children by using collagenase digestion method. The third generation cells were identified by flow cytometry and alizarin red and alkaline phosphatase (ALP) staining after osteogenic differentiation culture. The SHED were divided into blank control group (SHED without any treatment), empty group (SHED infected with empty lentivirus), HIF-1α overexpression group (SHED infected with HIF-1α overexpression lentivirus), Wnt inhibitor group (SHED interfered by IWR-1), and combination group (HIF-1α overexpressed SHED interfered by IWR-1). Real-time fluorescence quantitative PCR (qRT-PCR) and Western blot were used to analyze the expressions of HIF-1α mRNA and protein in the SHED of blank control group, empty group, and HIF-1α overexpression group. Then the SHED in 5 groups were induced differentiation into vascular endothelial cells for 14 days. The expressions of cell surface marker molecule [von Willebrand factor (vWF) and CD31] were detected by flow cytometry. The mRNA expressions of vascular cell adhesion protein 1 (VCAM-1), KDR (Kinase-inserted domain containing receptor), and VE-cadherin (VE) were analyzed by qRT-PCR. The protein expressions of phosphate-glycogen synthasc kinase 3β (p-GSK3β) and β-catenin were analyzed by Western blot. The tube forming ability of induced cells was detected by Matrigel tube forming experiment. The ability of endothelial cells to phagocytic lipid after differentiation was detected by DiI-labeled acetylated low density lipoprotein (DiI-Ac-LDL) phagocytosis.ResultsAfter identification, the cells were SHED. After lentivirus transfection, compared with the blank control group and the empty group, the expressions of HIF-1α mRNA and protein in the HIF-1α overexpression group increased significantly (P<0.05). Compared with the blank control group and the empty group, the expressions of VCAM-1, KDR, and VE mRNA, the percentages of vWF positive cells and CD31 positive cells, and the relative expression of β-catenin protein were significantly higher (P<0.05), the relative expression of p-GSK3β protein was significantly lower (P<0.05), the number of tubules formed and the ability to phagocytic lipids significantly increased (P<0.05) in the HIF-1α overexpression group; while the indicators in the Wnt inhibitor group were opposite to those in the HIF-1α overexpression group (P<0.05). Compared with the HIF-1α overexpression group, the expressions of VCAM-1, KDR, and VE mRNA, the percentages of vWF positive cells and CD31 positive cells, and the relative expression of β-catenin protein were significantly lower (P<0.05), the relative expression of p-GSK3β protein was significantly higher, and the number of tubules formed and the ability of phagocytosis of lipids significantly reduced, showing significant differences between groups (P<0.05).ConclusionOverexpression of HIF-1α can promote SHED to differentiate into vascular endothelial cells by activating Wnt/β-catenin signaling pathway.