Hypoxia-inducible factor-1αin myocardial infarction

Hypoxia-inducible factor 1(HIF1)has a crucial function in the regulation of oxygen levels in mammalian cells,especially under hypoxic conditions.Its importance in cardiovascular diseases,particularly in cardiac ischemia,is because of its ability to alleviate cardiac dysfunction.The oxygen-responsive subunit,HIF1α,plays a crucial role in this process,as it has been shown to have cardioprotective effects in myocardial infarction through regulating the expression of genes affecting cellular survival,angiogenesis,and metabolism.Furthermore,HIF1αexpression induced reperfusion in the ischemic skeletal muscle,and hypoxic skin wounds in diabetic animal models showed reduced HIF1αexpression.Increased expression of HIF1αhas been shown to reduce apoptosis and oxidative stress in cardiomyocytes during acute myocardial infarction.Genetic variations in HIF1αhave also been found to correlate with altered responses to ischemic cardiovascular disease.In addition,a link has been established between the circadian rhythm and hypoxic molecular signaling pathways,with HIF1αfunctioning as an oxygen sensor and circadian genes such as period circadian regulator 2 responding to changes in light.This editorial analyzes the relationship between HIF1αand the circadian rhythm and highlights its significance in myocardial adaptation to hypoxia.Understanding the changes in molecular signaling pathways associated with diseases,specifically cardiovascular diseases,provides the opportunity for innovative therapeutic interventions,especially in low-oxygen environments such as myocardial infarction.

DI-3-n-butylphthalide exerts neuroprotective effects by modulating hypoxia-inducible factor 1-alpha ubiquitination to attenuate oxidative stress-induced apoptosis

DI-3-n-butylphthalide is used to treat mild and moderate acute ischemic stroke.However,the precise underlying mechanism requires further investigation.In this study,we investigated the molecular mechanism of DI-3-n-butylphthalide action by various means.We used hydrogen peroxide to induce injury to PC12cells and RAW264.7 cells to mimic neuronal oxidative stress injury in stroke in vitro and examined the effects of DI-3-n-butylphthalide.We found that DI-3-nbutylphthalide pretreatment markedly inhibited the reduction in viability and reactive oxygen species production in PC12 cells caused by hydrogen peroxide and inhibited cell apoptosis.Furthermore,DI-3-n-butylphthalide pretreatment inhibited the expression of the pro-apoptotic genes Bax and Bnip3.DI-3-nbutylphthalide also promoted ubiquitination and degradation of hypoxia inducible factor 1α,the key transcription factor that regulates Bax and Bnip3 genes.These findings suggest that DI-3-n-butylphthalide exhibits a neuroprotective effect on stroke by promoting hypoxia inducible factor-1α ubiquitination and degradation and inhibiting cell apoptosis.

Hypoxia inducible factor-1alpha mediates protection of DL-3-n-butylphthalide in brain microvascular endothelial cells against oxygen glucose deprivation-induced injury

Studies have demonstrated that DL-3-n-butylphthalide can significantly alleviate oxygen glucose deprivation-induced injury of human umbilical vein endothelial cells at least partly associated with its enhancement on oxygen glucose deprivation-induced hypoxia inducible factor-1α expression.In this study,we hypothesized that DL-3-n-butylphthalide can protect against oxygen glucose deprivation-induced injury of newborn rat brain microvascular endothelial cells by means of upregulating hypoxia inducible factor-1α expression.MTT assay and Hoechst staining results showed that DL-3-n-butylphthalide protected brain microvascular endothelial cells against oxygen glucose deprivation-induced injury in a dose-dependent manner.Western blot and immunofluorescent staining results further confirmed that the protective effect was related to upregulation of hypoxia inducible factor-1α.Real-time RT-PCR reaction results showed that DL-3-n-butylphthalide reduced apoptosis by inhibiting downregulation of pro-apoptotic gene caspase-3 mRNA expression and upregulation of apoptosis-executive protease bcl-2 mRNA expression;however,DL-3-n-butylphthalide had no protective effects on brain microvascular endothelial cells after knockdown of hypoxia inducible factor-1α by small interfering RNA.These findings suggest that DL-3-n-butylphthalide can protect brain microvascular endothelial cells against oxygen glucose deprivation-induced injury by upregulating bcl-2 expression and downregulating caspase-3 expression though hypoxia inducible factor-1α pathway.

Is the hypoxia-inducible factor-1 alpha mRNA expression activated by ethanol-induced injury, the mechanism underlying alcoholic liver disease?

BACKGROUND: Excessive alcohol consumption can result in multiple organ injury, of which alcoholic liver disease (ALD) is the most common. With economic development and improvement of living standards, the incidence of diseases caused by alcohol abuse has been increasing in China, although its pathogenesis remains obscure. The aim of this study was to investigate the role of hypoxia in chronic ALD. METHODS: Twenty-eight male Sprague-Dawley rats were randomized into a control group (n=12) with a normal history and an experimental group (n=16) fed with 10 ml/ kg of 56% (vol/vol) ethanol once per day by gastric lavage for 24 weeks. At 24 weeks, blood samples were collected and then the rats were killed. Liver samples were frozen at -80 ℃ and used for RT-PCR; other liver samples were obtained for immunohistochemical staining. RESULTS: When the period of alcohol consumption increased, the positive rate of expression of hypoxia- inducible factor-1 alpha (HIF-1α) mRNA was more significantly elevated in the liver of the alcohol group than in the control group (P≤0.05). The HIF-1α protein located in the cytoplasm was seldom expressed in the control group, but significantly in the alcohol group (P≤0.01). CONCLUSION: HIF-1α mRNA expression was activated by ethanol-induced injury in this study, suggesting that hypoxia is involved in the underlying mechanism of ALD.

Effect of NADPH Oxidase Inhibitor Apocynin on the Expression of Hypoxia-induced Factor-1α and Endothelin-1 in Rat Carotid Body Exposed to Chronic Intermittent Hypoxia

The effects of nicotinamide adenine dinucleotide phosphate （NADPH） oxidase inhibitor apocynin on the enhanced hypoxia induced factor-let （HIF-lct） and endothelin-1 （ET-1） expression, elevated systolic blood pressure under chronic intermittent hypoxia （CIH） condition and its action mechanism were investigated. Thirty healthy 8-week old Sprague-Dawley （SD） male rats were randomly divided into three groups （n=10 each）： sham group, CIH group, and apocynin-treated CIH group. Tail artery systolic blood pressure was measured by tail-cuff method. Real-time fluorescence quantitative polymerase chain reaction （PCR） was used to detect the mRNA expression of HIF-lu and ET-1 in the carotid body, and the HIF-1a protein expression was examined by using Western blotting. The levels of malondialdehyde （MDA） and superoxide dismutase （SOD） were determined by using colorimetric method. In addition, the plasma ET-1 and HIF-1a levels were measured by using enzyme-linked immunosorbent assay. It was found that CIH exposure was associated with increased MDA levels, and apo- cynin-treated CIH animals showed reduction in MDA levels. Apocynin treatment prevented CIH-induced hypertension as well as CIH-induced decrease in SOD. The increases of HIF-1a and ET-1 mRNA along with HIF-la protein expression in the carotid body, and elevated circulating HIF-1a and ET-1 levels were observed in CIH-exposed animals. Treatment with apocynin significantly decreased the ET-1 mRNA, HIF-lct protein expression and circulating HIF-la level in CIH-exposed animals, and there was no statistically significant difference in the HIF-lu mRNA expression between CIH group and apo- cynin-treated group. These results indicated that apocynin alleviated CIH-induced hypertension by inhibiting NADPH oxidase, further leading to the reduced vasoconstrictor ET-1 level and oxidative stress. HIF-1a/ET-1 system signal pathway may interact with CIH-induced NADPH oxidase-dependent oxidative stress. Inhibition of NADPH oxidase activity may hopefully serve as a useful strategy for prevention and treatment of obstructive sleep apnea hypopnea syndrome-induced hypertension.

Desferoxamine preconditioning protects against cerebral ischemia in rats by inducing expressions of hypoxia inducible factor 1α and erythropoietin

Objective To investigate whether desferoxamine （DFO） preconditioning can induce tolerance against cerebral ischemia and its effect on the expression of hypoxia inducible factor 1 α （HIF- 1α） and erythropoietin （EPO） in vivo and in vitro. Methods Rat model of cerebral ischemia was established by middle cerebral artery occlusion with or without DFO administration. Infarct size was examined by TTC staining, and the neurological severity score was evaluated according to published method. Cortical neurons were cultured under ischemia stress which was mimicked by oxygen-glucose deprivation （OGD）, and the neuron damage was assessed by MTT assay. Immunofluorescent staining was employed to detect the expressions of HIF-1 and EPO. Results The protective effect induced by DFO （decreasing the infarction volume and ameliorating the neurological function） appeared at 2 d after administration ofDFO （post-DFO）, lasted until 7 d and disappeared at 14 d （P 〈 0.05）; the most effective action was observed at 3 d post-DFO. DFO induced tolerance of cultured neurons against OGD： neuronal viability was increased 23%, 34%, 40%, 48% and 56% at 8 h, 12 h, 24 h, 36 h, and 48 h, respectively, post-DFO （P 〈 0.05）. Immunofluorescent staining found that HIF-1 α and EPO were upregulated in the neurons of rat brain at 3 d and 7 d post-DFO; increase of HIF-1 α and EPO appeared in cultured cortex neurons at 36 h and 48 h post-DFO. Conclusion DFO induced tolerance against focal cerebral ischemia in rats, and exerted protective effect on OGD cultured cortical neurons. DFO significant induced the expression of HIF- 1 α and EPO both in vivo and in vitro. DFO preconditioning can protect against cerebral ischemia, which may be associated with the synthesis of HIF- 1 α and EPO.

Forskolin Modulates the Inhibitory Effect of C-Type Natriuretic Peptide on Hypoxia-Induced Atrial Dynamics and Hypoxia Inducible Factor 1 Alpha Activity

Our study investigated effects of C-type natriuretic peptide (CNP) on atrial dynamics and hypoxia inducible factor 1 alpha (HIF-1α) activity in perfused beating rat atria, under hypoxic conditions. Hypoxia significantly increased the levels of HIF-1α, concomitant with decreased trial dynamics. CNP (0.1 μmol/L) further decreased atrial dynamics under hypoxia and suppressed hypoxia-induced stimulation of HIF-1α expression. An adenylylcyclase (AC) activator, forskolin (0.1 μmol/L), significantly up-regulated atrial phosphodiesterase subtype 3A (PDE 3A) protein without affecting hypoxia-induced dynamics. In the presence of forskolin, the inhibitory effects of CNP on hypoxia-induced atrial dynamics and HIF-1α levels were significantly attenuated. Forskolin also prevented hypoxia-induced downregulation of PDE3A protein. These findings suggested that CNP inhibited atrial dynamics and HIF-1α activity in the isolated perfused beating rat atria under hypoxic conditions. Furthermore, both effects were modulated by the AC activator forskolin, through activation of CNP-PDE 3A signaling.

Human umbilical cord mesenchymal stem cells derivedexosomes on VEGF-A in hypoxic-induced mice retinal astrocytes and mice model of retinopathy of prematurity

AIM:To observe the effect of human umbilical cord mesenchymal stem cells(hUCMSCs)secretions on the relevant factors in mouse retinal astrocytes,and to investigate the effect of hUCMSCs on the expression of vascular endothelial growth factor-A(VEGF-A)and to observe the therapeutic effect on the mouse model of retinopathy of prematurity(ROP).METHODS:Cultured hUCMSCs and extracted exosomes from them and then retinal astrocytes were divided into control group and hypoxia group.MTT assay,flow cytometry,reverse transcription-polymerase chain reaction(RT-PCR)and Western blot were used to detect related indicators.Possible mechanisms by which hUCMSCs exosomes affect VEGF-A expression in hypoxia-induced mouse retinal astrocytes were explored.At last,the efficacy of exosomes of UCMSCs in a mouse ROP model was explored.Graphpad6 was used to comprehensively process data information.RESULTS:The secretion was successfully extracted from the culture supernatant of hUCMSCs by gradient ultracentrifugation.Reactive oxygen species(ROS)and hypoxia inducible factor-1α(HIF-1α)of mice retinal astrocytes under different hypoxia time and the expression level of VEGF-A protein and VEGF-A mRNA increased,and the ROP cell model was established after 6h of hypoxia.The secretions of medium and high concentrations of hUCMSCs can reduce ROS and HIF-1α,the expression levels of VEGF-A protein and VEGF-A mRNA are statistically significant and concentration dependent.Compared with the ROP cell model group,the expression of phosphatidylinositol 3-kinase(PI3K)/protein kinase B(AKT)/mammalian target of rapamycin(mTOR)signal pathway related factors in the hUCMSCs exocrine group is significantly decreased.The intravitreal injection of the secretions of medium and high concentrations of hUCMSCs can reduce VEGF-A and HIF-1αin ROP model tissues.HE staining shows that the number of retinal neovascularization in ROP mice decreases with the increase of the dose of hUCMSCs secretion.CONCLUSION:In a hypoxia induced mouse retinal astrocyte model,hUCMSCs exosomes are found to effectively reduce the expression of HIF-1αand VEGF-A,which are positively correlated with the concentration of hUCMSCs exosomes.HUCMSCs exosomes can effectively reduce the number of retinal neovascularization and the expression of HIF-1αand VEGF-A proteins in ROP mice,and are positively correlated with drug dosage.Besides,they can reduce the related factors on the PI3K/AKT/mTOR signaling pathway.

Quantitative analysis of hepatic hypoxia-inducible factor-1α and its abnormal gene expression during the formation of hepatocellular carcinoma

BACKGROUND:Hepatic hypoxia-inducible factor-1(HIF-1) is activated in the progression of hepatocellular carcinoma (HCC).This study aimed to investigate the dynamic alterations of HIF-1αand its gene expression so as to explore the relationship between HIF-1αexpression and hepatocarcinogenesis at the early stage of HCC. METHODS:A hepatoma model was made with 2-fluorenyl- acetamide(2-FAA)in male Sprague-Dawley rats.Morphological changes of rat hepatocytes were assessed pathologically (HE staining).The dynamic expression of hepatic and circulating HIF-1αwas quantitatively analyzed by ELISA. The gene fragments of hepatic HIF-1αmRNA were amplified by RT-PCR and confirmed by sequencing.The cellular distribution of hepatic HIF-1αexpression was confirmed by immunohistochemistry. RESULTS:Histological examination confirmed granulelike degeneration to atypical hyperplasia and HCC development in rat hepatocytes and progressive increases in the levels of hepatic and circulating HIF-1αand its gene expression during the course.The levels of HIF-1α expression in the liver and blood of rats with hepatoma were significantly higher than those in normal ratsand those with degeneration.Immunohistochemical analysis confirmed the positive expression and hepatocyte distribution of HIF-1αin the development of rat hepatoma. A positive relationship was found between HIF-1α expression in the liver and blood(P<0.01). CONCLUSIONS:The above observations support the hypothesis that the overexpression of HIF-1αand its gene are closely associated with the malignant transformation of hepatocytes and play an important role at the stage of hepatocarcinogenesis.

Hypoxia inducible factor-1αaccumulation in steatotic liver preservation:Role of nitric oxide

AIM:To examine the relevance of hypoxia inducible factor(HIF-1)and nitric oxide(NO)on the preservation of fatty liver against cold ischemia-reperfusion injury(IRI). METHODS:We used an isolated perfused rat liver model and we evaluated HIF-1αin steatotic and non-steatotic livers preserved for 24 h at 4℃in University of Wisconsin and IGL-1 solutions,and then subjected to 2 h of normothermic reperfusion.After normoxic reperfusion,liver enzymes,bile production,bromosulfophthalein clearance,as well as HIF-1αand NO[endothelial NO synthase(eNOS)activity and nitrites/nitrates]were also measured.Other factors associated with the higher susceptibility of steatotic livers to IRI,such as mitochondrial damage and vascular resistance were evaluated. RESULTS:A significant increase in HIF-1αwas found in steatotic and non-steatotic livers preserved in IGL-1 after cold storage.Livers preserved in IGL-1 showed a significant attenuation of liver injury and improvement in liver function parameters.These benefits were enhanced by the addition of trimetazidine(an antiischemic drug),which induces NO and eNOS activation, to IGL-1 solution.In normoxic reperfusion,the presence of NO favors HIF-1αaccumulation,promoting also the activation of other cytoprotective genes,such as hemeoxygenase-1. CONCLUSION:We found evidence for the role of the HIF-1α/NO system in fatty liver preservation,especially when IGL-1 solution is used.

Prognostic value of hypoxia-inducible factor-1 alpha and prolyl 4-hydroxylase beta polypeptide overexpression in gastric cancer

AIM To investigate the relationship between hypoxia-inducible factor-1α(HIF-1α), prolyl 4-hydroxylase beta(P4 HB) expression, and clinicopathologic parameters, as well as the prognostic value of these genes for patients with gastric cancer(Gc).METHODS Hypoxia is a critical factor that shapes the Gc microenvironment. In previous reports, we have demonstrated that P4 HB is a potential target of HIF-1α. In the present study, gene expression profiling interactive analysis(GEPIA) was used to analyze the relationship between P4 HB and hypoxia-associated genes. To this end, 428 Gc tissue samples were used to analyze the expression of HIF-1α and P4 HB via immunohistochemical staining. Patient samples were classified as having weak-expression or over-expression both in terms of HIF-1α and P4 HB. Correlations between biomarkers and clinicopathological factors were analyzed to predict survival. RESULTS P4 HB demonstrated a positive correlation with hypoxiaassociated genes(P < 0.05). HIF-1α and P4 HB overexpression have a significant correlation with TNM staging(χ2 = 23.32, P = 0.00; χ2 = 65.64, P = 0.00) and peritoneum cavity metastasis(χ2 = 12.67, P = 0.00; χ2 = 39.29, P = 0.00). In univariate analysis, patients with a high HIF-1α expression trend had a shorter disease-free survival(DFS: 44.80 mo vs 22.06 mo) and overall survival(OS: 49.58 mo vs 39.92 mo). P4 HB overexpression reflected similar results: patients with over-expression of P4 HB had a shorter survival time than those with weak-expression(DFS: 48.03 mo vs 29.64 mo, OS: 52.48 mo vs 36.87 mo). Furthermore, HIF-1α is also a clinicopathological predictor of dismal prognosis according to multivariate analysis(DFS, 95%c I: 0.52-0.88, P < 0.00; OS, 95%c I: 0.50-0.85, P < 0.00). However, P4 HB was meaningful in DFS(95%c I: 0.58-1.00, P < 0.05) but not in OS(95%c I: 0.72-1.23, P > 0.05).CONCLUSION Overexpression of HIF-1α and P4 HB is associated with poor prognosis in patients with Gc. Thus, these genes may be potential prognostic biomarker candidates in GC.

Hypoxia upregulates hypoxia inducible factor(HIF)-3α expression in lung epithelial cells: characterization and comparison with HIF-1α

The role of the hypoxia-inducible factor(HIF)subunits 1α and 2α in response to hypoxia is well established in lungepithelial cells,whereas little is known about HIF-3α with respect to transcriptional and translational regulation by hy-poxia.HIF-3α and HIF-1α are two similar but distinct basic helix-loop-helix-PAS proteins,which have been postulatedto activate hypoxia responsive genes in response to hypoxia.Here,we used quantitative real time RT-PCR and immu-noblotting to determine the activation of HIF-3α vs.HIF-1α by hypoxia.HIF-3α was strongly induced by hypoxia(1%O_2)both at the level of protein and mRNA due to an increase in protein stability and transcriptional activation,whereasHIF-1α protein and mRNA levels enhanced transiently and then decreased because of a reduction in its mRNA stabilityin A549 cells,as measured on mRNA and protein levels.Interestingly,HIF-3α and HIF-1α exhibited strikingly similarresponses to a variety of activating or inhibitory pharmacological agents.These results demonstrate that HIF-3α is ex-pressed abundantly in lung epithelial cells,and that the transcriptional induction of HIF-3α plays an important role in theresponse to hypoxia in vitro.Our findings suggest that HIF-3α,as a member of the HIF system,is complementary ratherthan redundant to HIF-1α induction in protection against hypoxic damage in alveolar epithelial cells.

Expression of Nerve Growth Factor and Hypoxia Inducible Factor-1α and Its Correlation with Angiogenesis in Non-Small Cell Lung Cancer

Summary： In order to investigate the expression of nerve growth factor （NGF） and hypoxia inducible factor-1α （HIF-1α） and its correlation with angiogenesis in non-small cell lung cancer （NSCLC）, paraffin-embedded tissue blocks from 20 patients with NSCLC were examined. Twenty corresponding para-cancerous lung tissue specimens were obtained to serve as a control. The expression of NGF, HIF-1α, and vascular endothelial growth factor （VEGF） in the NSCLC tissues was detected by using immunohistochemistry. The microvascular density （MVD） was determined by CD31 staining. The resuits showed that the expression levels ofNGF, HIF-1α and VEGF in the NSCLC tissues were remarkably higher than those in the para-cancerous lung tissues （P〈0.05）. There was significant difference in the MVD between the NSCLC tissues （9.19±1.43） and para-cancerous lung tissues （2.23±1.19） （P〈0.05）. There were positive correlations between NGF and VEGF, between HIF-1α and VEGF, and between NGF and HIF-1α in NSCLC tissues, with the spearman correlation coefficient being 0.588, 0.519 and 0.588, respectively. In NSCLC tissues, the MVD had a positive correlation with the three factors （P〈0.05）. Theses results suggest that NGF and HIF-1α are synergically involved in the angiogenesis of NSCLC.

Metabolic shift in liver: Correlation between perfusion temperature and hypoxia inducible factor-1α

AIM: To study at what temperature the oxygen carried by the perfusate meets liver requirements in a model of organ perfusion. METHODS: in this study, we correlated hypoxia induciblefactor(Hi F)-1α expression to the perfusion temperature and the hepatic oxygen uptake in a model of isolated perfused rat liver. Livers from Wistar rats were perfused for 6 h with an oxygenated medium at 10, 20, 30 and 37 ℃. Oxygen uptake was measured by an oxygen probe; lactate dehydrogenase activity, lactate release and glycogen were measured spectrophotometrically; bile flow was gravitationally determined; p H of the perfusate was also evaluated; Hi F-1α m RNA and protein expression were analyzed by real time-polymerase chain reaction and ELi SA, respectively. RESULTS: Livers perfused at 10 and 20 ℃ showed no difference in lactate dehydrogenase release after 6 h of perfusion(0.96 ± 0.23 vs 0.93 ± 0.09 m U/min per g) and had lower hepatic damage as compared to 30 and 37 ℃(5.63 ± 0.76 vs 527.69 ± 45.27 m U/min per g, respectively, P s < 0.01). After 6 h, tissue ATP was significantly higher in livers perfused at 10 and 20 ℃than in livers perfused at 30 and 37 ℃(0.89 ± 0.06 and 1.16 ± 0.05 vs 0.57 ± 0.09 and 0.33 ± 0.08 nmol/mg, respectively, P s < 0.01). No sign of hypoxia was observed at 10 and 20 ℃, as highlighted by low lactate release respect to livers perfused at 30 and 37 ℃(121.4 ± 12.6 and 146.3 ± 7.3 vs 281.8 ± 45.3 and 1094.5 ± 71.7 nmol/m L, respectively, P s < 0.02), and low relative Hi F-1α m RNA(0.40 ± 0.08 and 0.20 ± 0.03 vs 0.60 ± 0.20 and 1.47 ± 0.30, respectively, P s < 0.05) and protein(3.72 ± 0.16 and 3.65 ± 0.06 vs 4.43 ± 0.41 and 6.44 ± 0.82, respectively, P s < 0.05) expression.CONCLUSION: Livers perfused at 10 and 20 ℃ show no sign of liver injury or anaerobiosis, in contrast to livers perfused at 30 and 37 ℃.

Hypoxia inducible factor-1 alpha stabilization for regenerative therapy in traumatic brain injury

Mild traumatic brain injury（TBI）, also called concussion, initiates sequelae leading to motor deficits, cognitive impairments and subtly compromised neurobehaviors. While the acute phase of TBI is associated with neuroinflammation and nitroxidative burst, the chronic phase shows a lack of stimulation of the neurorepair process and regeneration. The deficiency of nitric oxide（NO）, the consequent disturbed NO metabolome, and imbalanced mechanisms of S-nitrosylation are implicated in blocking the mechanisms of neurorepair processes and functional recovery in the both phases. Hypoxia inducible factor-1 alpha（HIF-1α）, a master regulator of hypoxia/ischemia, stimulates the process of neurorepair and thus aids in functional recovery after brain trauma. The activity of HIF-1α is regulated by NO via the mechanism of S-nitrosylation of HIF-1α. S-nitrosylation is dynamically regulated by NO metabolites such as S-nitrosoglutathione（GSNO） and peroxynitrite. GSNO stabilizes, and peroxynitrite destabilizes HIF-1α. Exogenously administered GSNO was found not only to stabilize HIF-1α and to induce HIF-1α-dependent genes but also to stimulate the regeneration process and to aid in functional recovery in TBI animals.

Expression of caspase-3 and hypoxia inducible factor 1αin hepatocellular carcinoma complicated by hemorrhage and necrosis

BACKGROUND Hepatocellular carcinoma(HCC)is a malignant tumor that occurs in the liver.Its onset is latent,and it shows high heterogeneity and can readily experience intrahepatic metastasis or systemic metastasis,which seriously affects patients’quality of life.Numerous studies have shown that hypoxia inducible factor1α(HIF-1α)plays a significant role in the occurrence and development of tumors,as it promotes the formation of intratumoral vessels and plays a key role in their metastasis and invasion.Some studies have reported that caspase-3,which is induced by various factors,is involved in the apoptosis of tumor cells.AIM To investigate the expression of caspase-3 and HIF-1αand their relationship to the prognosis of patients with primary HCC complicated by pathological changes of hemorrhage and necrosis.METHODS A total of 88 patients with HCC complicated by pathological changes of hemorrhage and necrosis who were treated at our hospital from January 2017 to December 2019 were selected.The expression of caspase-3 and HIF-1αin HCC and paracancerous tissues from these patients was assessed.RESULTS The positive expression rate of caspase-3 in HCC tissues was 27.27%,which was significantly lower than that in the paracancerous tissues(P<0.05),while the positive expression rate of HIF-1αwas 72.73%,which was significantly higher than that in the paracancerous tissues(P<0.05).The positive expression rates for caspase-3 in tumor node metastasis(TNM)stage III and lymph node metastasis tissues were 2.78%and 2.50%,respectively,which were significantly lower than those in TNM stage I-II and non-lymph node metastasis tissues(P<0.05).The positive expression rates of HIF-1αin TNM stage III,lymph node metastasis,and portal vein tumor thrombus tissues were 86.11%,87.50%,and 88.00%,respectively,and these values were significantly higher than those in TNM stage I-II,non-lymph node metastasis,and portal vein tumor thrombus tissues(P<0.05).The expression of caspase-3 and HIF-1αin HCC tissues were negatively correlated(rs=−0.426,P<0.05).The median overall survival time of HCC patients was 18.90 mo(95%CI:17.20–19.91).The results of the Cox proportional risk regression model analysis showed that TNM stage,portal vein tumor thrombus,lymph node metastasis,caspase-3 expression,and HIF-1αexpression were the factors influencing patient prognosis(P<0.05).CONCLUSION The expression of caspase-3 decreases and HIF-1αincreases in HCC tissues complicated by pathological changes of hemorrhage and necrosis,and these are related to clinicopathological features and prognosis.

Effect of lentiviral vector-mediated overexpression of hypoxia-inducible factor 1 alpha delivered by pluronic F-127 hydrogel on brachial plexus avulsion in rats

Brachial plexus avulsion often results in massive motor neuron death and severe functional deficits of target muscles. However, no satisfactory treatment is currently available. Hypoxia-inducible factor 1α is a critical molecule targeting several genes associated with ischemia-hypoxia damage and angiogenesis. In this study, a rat model of brachial plexus avulsion-reimplantation was established, in which C5–7 ventral nerve roots were avulsed and only the C6 root reimplanted. Different implants were immediately injected using a microsyringe into the avulsion-reimplantation site of the C6 root post-brachial plexus avulsion. Rats were randomly divided into five groups: phosphate-buffered saline, negative control of lentivirus, hypoxia-inducible factor 1α(hypoxia-inducible factor 1α overexpression lentivirus), gel(pluronic F-127 hydrogel), and gel + hypoxia-inducible factor 1α(pluronic F-127 hydrogel + hypoxia-inducible factor 1α overexpression lentivirus). The Terzis grooming test was performed to assess recovery of motor function. Scores were higher in the hypoxia-inducible factor 1α and gel +hypoxia-inducible factor 1α groups(in particular the gel + hypoxia-inducible factor 1α group) compared with the phosphate-buffered saline group. Electrophysiology, fluorogold retrograde tracing, and immunofluorescent staining were further performed to investigate neural pathway reconstruction and changes of neurons, motor endplates, and angiogenesis. Compared with the phosphate-buffered saline group, action potential latency of musculocutaneous nerves was markedly shortened in the hypoxia-inducible factor 1α and gel + hypoxia-inducible factor1α groups. Meanwhile, the number of fluorogold-positive cells and ChAT-positive neurons, neovascular area(labeled by CD31 around av ulsed sites in ipsilateral spinal cord segments), and the number of motor endplates in biceps brachii(identified by α-bungarotoxin) were all visibly increased, as well as the morphology of motor endplate in biceps brachil was clear in the hypoxia-inducible factor 1α and gel + hypoxia-inducible factor 1α groups. Taken together, delivery of hypoxia-inducible factor 1α overexpression lentiviral vectors mediated by pluronic F-127 effectively promotes spinal root regeneration and functional recovery post-brachial plexus avulsion. All animal procedures were approved by the Institutional Animal Care and Use Committee of Guangdong Medical University, China.

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.

Meta-analysis of immunohistochemical expression of hypoxia inducible factor-1α as a prognostic role in gastric cancer

AIM: To conduct a meta-analysis to evaluate the prognostic role of hypoxia inducible factor-1&#x003b1; (HIF-1&#x003b1;) expression in gastric cancer.

Wortmannin influences hypoxia-inducible factor-1 alpha expression and glycolysis in esophageal carcinoma cells

AIM: To investigate the influence of phosphatidylinositol-3-kinase protein kinase B(PI3K/AKT)-HIF-1α signaling pathway on glycolysis in esophageal carcinoma cells under hypoxia. METHODS: Esophageal carcinoma cell lines Eca109 and TE13 were cultured under hypoxia environment, and the protein, m RNA and activity levels of hypoxia inducible factor-1 alpha(HIF-1α), glucose transporter 1, hexokinase-Ⅱ, phosphofructokinase 2 and lactate dehydrogenase-A were determined. Supernatant lactic acid concentrations were also detected. The PI3K/AKT signaling pathway was then inhibited with wortmannin, and the effects of hypoxia on the expression or activities of HIF-1α, associated glycolytic enzymes and lactic acid concentrations were observed. Esophageal carcinoma cells were then transfected with interference plasmid with HIF-1α-targeting si RNA to assess impact of the high expression of HIF-1α on glycolysis.RESULTS: HIF-1α is highly expressed in the esophageal carcinoma cell lines tested, and with decreasing levels of oxygen, the expression of HIF-1α and the associated glycolytic enzymes and the extracellular lactic acid concentration were enhanced in the esophageal carcinoma cell lines Eca109 and TE13. In both normoxia and hypoxic conditions, the level of glycolytic enzymesand the secretion of lactic acid were both reduced by wortmannin. The expression and activities of glycolytic enzymes and the lactic acid concentration in cells were reduced by inhibiting HIF-1α, especially the decreasing level of glycolysis was significant under hypoxic conditions.CONCLUSION: The PI3K/AKT pathway and HIF-1α are both involved in the process of glycolysis in esophageal cancer cells.