脑出血小鼠行为学改变和低氧诱导因子-1α的表达

目的:研究成年小鼠脑出血(ICH)后行为学改变和低氧诱导因子-1α(HIF-1α)的表达和分布。方法:40只雄性昆明小鼠随机分为行为学检测组(n=10)和HIF-1α免疫组织化学染色组(n=20)。立体定向注射型胶原酶建立小鼠纹状体ICH模型。在ICH后第7及14天处死小鼠,分别进行行为学检测和HIF-1α免疫组织化学染色,行为学评分采用Berderson评分法,对HIF-1α免疫阳性细胞作细胞计数。结果:ICH后第7及14天小鼠出现严重的神经功能障碍;小鼠ICH后第7天及14天出血侧的皮质和出血灶周半暗带HIF-1α阳性细胞数显著增加。结论:小鼠ICH后1周内神经功能障碍明显,脑出血后的缺氧能刺激HIF-1α表达增加。

Upregulation of hypoxia inducible factor 1α mRNA is associated with elevated vascular endothelial growth factor expression and excessive angiogenesis and predicts a poor prognosis in gastric carcinoma

AIM： To investigate the implication of the hypoxia inducible factor HIF-1α mRNA in gastric carcinoma and its relation to the expression of vascular endothelial growth factor （VEGF） protein, tumor angiogenesis invasion/metastasis and the patient＇s survival. METHODS： In situ hybridization was used to examine expression of HIF-1α mRNA, and immunohistochemical staining was used to examine expression of VEGF protein and CD34 in 118 specimens from patients with gastric carcinoma. RESULTS： The positive rates of HIF-1α mRNA and VEGF protein were 49.15% and 55.92%, respectively. Positive expressions of HIF-1α and VEGF in stage T3-T4 tumors and those with vessel invasion, lymph node metastasis and distant metastasis were dramatically stronger than stage T1-T2 cases and those without vessel invasion, lymph node metastasis and distant metastasis. The mean microvascular density （MVD） in stage T3-T4 tumors and those with vessel invasion, lymph node metastasis and distant metastasis was significantly higher than stage T1-T2 tumors and those without vessel invasion, lymph node metastasis and distant metastasis. The mean MVD in tumors with positive HIF-1α and VEGF expression was significantly higher than that in tumors with negative HIF-1α and VEGF expression. The expression of HIF- 1α was positively correlated with VEGF protein. There were positive correlations between MVD and expression of HIF-1α and VEGF. The mean survival time and the S-year survival rate in cases with positive expression HIF-1α and VEGF and MVD value ≥ 41.5/0.72 mm^2 were significantly lower than those with negative expression of HIF-1α and VEGF and MVD value 〈 41.5/0.72 mm^2. CONCLUSION： Overexpression of HIF-1α is found in gastric carcinoma. HIF-1α may induce the angiogenesis in gastric carcinoma by upregulating the transcription of VEGF gene, and take part in tumor invasion and metastasis. They can be used as prognostic markers of gastric cancer in clinical practice.

Hypoxia inducible factor-1α mediates protective effects of ischemic preconditioning on ECV-304 endothelial cells

AIM: To investigate whether hypoxia inducible factor-1α (HIF-1α) is linked to the protective effects of ischemic preconditioning (IP) on sinusoidal endothelial cells against ischemia/reperfusion injury. METHODS: Sinusoidal endothelial cell lines ECV-304 were cultured and divided into four groups: control group, cells were cultured in complete DMEM medium; cold anoxia/warm reoxygenation (A/R) group, cells were preserved in a 4℃ UW solution in a mixture of 95% N2 and 5% CO2 for 24 h; anoxia-preconditioning (APC) group, cells were treated with 4 cycles of short anoxia and reoxygenation before prolonged anoxia- preconditioning treatment; and anoxia-preconditioning and hypoxia inducible factor-1α (HIF-1α) inhibitor (I-HIF-1) group, cells were pretreated with 5 μm of HIF-1α inhibitor NS398 in DMEM medium before subjected to the same treatment as group APC. After the anoxia treatment, each group was reoxygenated in a mixture of 95% air and 5% CO2 incubator for 6 h. Cytoprotections were evaluated by cell viabilities from Trypan blue, lactate dehydrogenase (LDH) release rates, and intracellular cell adhesion molecule-1 (ICAM-1) expressions. Expressions of HIF-1α mRNA and HIF-1α protein from each group were determined by the RT-PCR method and Western blotting, respectively. RESULTS: Ischemia preconditioning increased cell viability, and reduced LDH release and ICAM-1 expressions. Ischemia preconditioning also upregulated the HIF-1α mRNA level and HIF-1α protein expression. However, all of these changes were reversed by HIF-1α inhibitor NS398.CONCLUSION: Ischemia preconditioning effectively inhibited cold hypoxia/warm reoxygenation injury to endothelial cells, and the authors showed for the first time HIF-1α is causally linked to the protective effects of ischemic preconditioning on endothelial cells.

The construction of siRNA plasmid targeting mouse HIF-1α and in vitro study of its inhibition effect

Objective To construct effective RNA-interference plasmids targeting mouse HIF-la gene and testify their effects and specificities in interfering HIF-1α expression. Methods Three RNA-interference plasmids targeting mouse HIF- 1α gene, pBS/U6/HIF-1α-siRNAI-Ⅲ, were constructed and identified using double digestion method in the present study. RT-PCR, immunostaining and western blotting were employed to detect the expression alterations of HIF-1α in 293T cells following transfections of the three plasmids, respectively. The interference effect of pBS/U6/HIF1αi-II in SH-SY5Y cell line was further investigated. Results All the three RNA-interference plasmids, especially pBS/U6/HIF1αi-Ⅱ, showed significant inhibition in HIF-1α expression in 293T cell line. pBS/U6/HIF1αi-Ⅱ could also inhibit HIF-1α expression in SH-SY5Y cell line, in a dosedependent way. Conclusion Plasmid pBS/U6/HIF1αi-Ⅱ constructed in our study can effectively and specifically inhibit HIF- 1α expression, and its role in neural tube development and dysfunction will be further investigated. Construct of pBS/U6/ HIF1αi-Ⅱ plasmid will provide a useful tool to study the role of HIF-1 pathway in embryogenesis, oncogenesis and i schemia development.

Hypoxia-inducible factor 1 and breast cancer metastasis

Accumulating evidence has shown that the hypoxic microenvironment, which is critical during cancer development, plays a key role in regulating breast cancer progression and metastasis. The effects of hypoxia-inducible factor 1 （HIF-1）, a master regulator of the hypoxic response, have been extensively studied during these processes. In this review, we focus on the roles of HIF-1 in regulating breast cancer cell metastasis, specifically its effects on multiple key steps of metastasis, such as epithelial-mesenchymal transition （EMT）, invasion, extravasation, and metastatic niche formation. We also discuss the roles of HIF-l-regulated non-coding RNAs in breast cancer metastasis, and therapeutic opportunities for breast cancer through targeting the HIF-1 pathway,

Association of HIF-1αexpression and cell apoptosis after traumatic brain injury in the rat

Objective: To explore the expression of hypoxia inducible factor-1α (HIF-1α) and the correlation between HIF-1α and apoptosis after traumatic brain injury. Methods: Using experimental traumatic brain injury in the rats, the expression of HIF-1α was studied by immunohisto-chemistry in cerebral tissue, apoptotic cell death was evaluated with TUNEL (transferase-mediated X-dUTP nick end labeling), and double-labeled immunohistochemistry and TUNEL methods were used to investigate the relationship between HIF-1α and apoptosis. Results: There was remarkable difference in the expression of HIF-1α between the experimental groups and the control groups (P< 0.01), in the experimental groups, the expression of HIF-1α at 48 hours was highest; the evidence of apoptotic cell death after experimental traumatic brain injury was found by TUNEL; the apoptotic percentage increased or decreased according to the changes of the positive expression of HIF-1α (r= 0.99). Conclusions: The results suggest that secondary brain ischemia plays a crucial role in apoptotic cell death after traumatic brain injury; HIF-1α can prompt apoptotic cell death after experimental traumatic brain injury.

Ursolic acid sensitized colon cancer cells to chemotherapy under hypoxia by inhibiting MDR1 through HIF-1α

Objective： To explore the efficacy of ursolic acid in sensitizing colon cancer cells to chemotherapy under hypoxia and its underlying mechanisms. Methods： Three colon cancer cell lines （RKO, LoVo, and SW480） were used as in vitro models. 5-Fluorouracil （5-FU） and oxaliplatin were used as chemotherapeutic drugs. Cell viability and apoptosis were tested to evaluate the sensitivity of colon cancer cells to chemotherapy. The transcription and ex- pression levels of hypoxia-inducible factor-1α （HIF-1α）, multidrug resistance gene 1 （MDR1）, and vascular endothelial growth factors （VEGF） were assessed by quantitative real-time polymerase chain reaction （qRT-PCR） and im- munoblotting. Cycloheximide and MG132 were used to inhibit protein synthesis and degradation, respectively. In vitro tube formation assay was used to evaluate angiogenesis. Results： We demonstrated the chemosensitizing effects of ursolic acid with 5-FU and oxaliplatin in three colon cancer cell lines under hypoxia. This effect was correlated to its inhibition of MDR1 through HIF-la. Moreover, ursolic acid was capable of inhibiting HIF-1α accumulation with little effects on its constitutional expression in normoxia. In addition, ursolic acid also down-regulated VEGF and inhibited tumor angiogenesis. Conclusions： Ursolic acid exerted chemosensitizing effects in colon cancer cells under hypoxia by inhibiting HIF-la accumulation and the subsequent expression of the MDR1 and VEGF.

The hypoxia signaling pathway and hypoxic adaptation in fishes

The hypoxia signaling pathway is an evolutionarily conserved cellular signaling pathway present in animals ranging from Caenorhabditis elegans to mammals.The pathway is crucial for oxygen homeostasis maintenance.Hypoxia-inducible factors(HIF-1αand HIF-2α)are master regulators in the hypoxia signaling pathway.Oxygen concentrations vary a lot in the aquatic environment.To deal with this,fishes have adapted and developed varying strategies for living in hypoxic conditions.Investigations into the strategies and mechanisms of hypoxia adaptation in fishes will allow us to understand fish speciation and breed hypoxia-tolerant fish species/strains.This review summarizes the process of the hypoxia signaling pathway and its regulation,as well as the mechanism of hypoxia adaptation in fishes.

The effect of spironolactone on the levels of GATA4 protein and hypoxia inducible factor-1α in patients receiving coronary stent implantation

In the present study,we aimed to explore the protective effect of spironolactone on cardiac function in patients undergoing coronary stent implantation by determining the serum levels of GATA4 and hypoxia-inducible factor-1α(HIF-1α)proteins before and after the coronary stent implantation.A total of 134 patients undergoing coronary stent implantation in our hospital from March 2019 to March 2020 were retrospectively selected using the propensity score matching(PSM)method.Of the 134 patients,67 patients taking spironolactone were used as a test group,and the other 67 patients without taking spironolactone were used as a control group.In all patients,the levels of serum GATA4,HIF-1α,and troponin I proteins were determined before as well as 24 h and 6 months after the coronary stent implantation.Left ventricular ejection fraction(LVEF)and left ventricular systolic global longitudinal strain(GLS)were determined before and 6 months after the coronary stent implantation.There were no significant differences in the HIF-1αlevel between the two groups before and 6 months after the operation,while the HIF-1αlevel was significantly lower in the test group compared with the control group at 24 h after the operation(P<0.01).There were no significant differences in the GATA4 protein level between the two groups before and 24 h after the operation,while the GATA4 protein level was significantly lower in the test group compared with the control group at 6 months after the operation(P<0.01).There was no significant difference in LVEF between the two groups before and 6 months after the operation.GLS was significantly improved at 6 months after the operation compared with that before the operation in both groups,while GLS was significantly better in the test group compared with the control group at 6 months after the operation(P<0.01).Collectively,spironolactone could protect cardiac function probably by improving myocardial hypoxia and inhibiting myocardial remodeling.