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.

Association of hypoxia-inducible factor-1α (HIF1α) 1772C/T genepolymorphism with susceptibility to renal cell carcinoma/prostatecancer

In this study,we used a meta-analysis method to evaluate the relationship between hypoxia-inducible factor-1α(HIF1α)1772C/T gene polymorphism(rs 11549465)and renal cell carcinoma(RCC)/prostate cancer risk.We searched for relevant studies(before March 1,2019)on Cochrane Library,Embase,and PubMed.Studies meeting the inclusion criteria were recruited into this meta-analysis.The outcome of dichotomous data was showed in the way of odds ratios(OR),and 95%confidence intervals(CI)were also counted.In this investigation,there was no association between HIF1α1772C/T gene polymorphism and susceptibility to RCC in Caucasians,Asians as well as overall populations.In addition,HIF1α1772C/T gene polymorphism was not found to be relevant to the survival in RCC.Interestingly,the T allele was relevant to prostate cancer risk in all populations,but not in Caucasians and Asians.However,the TT genotype and the CC genotype were not related to prostate cancer susceptibility in Asian,Caucasian,and all populations.In conclusion,the T allele of the HIF1α1772C/T gene polymorphism was related to prostate cancer risk in the overall populations.

小檗碱调节HIF-1α/VEGF信号通路对皮肤溃疡大鼠血管生成和创面愈合的影响

目的:探究小檗碱(BR)调节缺氧诱导因子-1α(HIF-1α)/血管内皮生长因子(VEGF)信号通路对皮肤溃疡大鼠血管生成和创面愈合的影响。方法:取SD大鼠采用创面局部多次涂抹冰醋酸建立皮肤溃疡模型,随机数字法分组,包括模型组(M组)、小檗碱低剂量组(BR-L组)、小檗碱高剂量组(BR-H组)、小檗碱高剂量+空载组(BR-H+pc-DNA组)、小檗碱高剂量+HIF-1α敲低组(BR-H+pc-HIF-1αKD组),每组10只,另选10只SD大鼠作为对照组(C组)。以药物分组处理3周后,测定各组大鼠创面愈合率;HE染色检测各组大鼠皮肤溃疡创面组织病理形态;免疫组织化学染色检测各组大鼠皮肤溃疡创面组织微血管密度(MVD)及胶原蛋白Ⅰ(CollagenⅠ)与纤维结合蛋白(FN)表达;酶联免疫吸附测定(ELISA)各组大鼠血清及皮肤溃疡创面组织炎性因子IL-6、IL-8表达水平;免疫印迹法检测各组大鼠皮肤溃疡创面组织HIF-1α/VEGF通路蛋白表达水平。结果:与C组相比,M组大鼠创面组织MVD、血清及创面组织IL-6、IL-8水平升高(均P<0.05)。与M组相比,BR-L组、BR-H组、BR-H+pc-DNA组大鼠创面愈合率、创面组织MVD、HIF-1α及VEGF蛋白表达均升高(均P<0.05),血清及创面组织IL-6、IL-8水平均降低(均P<0.05),且高剂量小檗碱作用更强。敲低HIF-1α可减弱BR对模型组大鼠各指标的作用。结论:小檗碱可通过上调HIF-1α/VEGF通路而降低炎性因子表达,抑制炎症,增强皮肤溃疡大鼠血管生成和胶原形成,促进其创面愈合。

Activation of hypoxia-inducible factor 1 attenuates periapical inflammation and bone loss

Hypoxia（low oxygen level） is an important feature during infections and affects the host defence mechanisms. The host has evolved specific responses to address hypoxia, which are strongly dependent on the activation of hypoxia-inducible factor 1（HIF-1）.Hypoxia interferes degradation of HIF-1 alpha subunit（HIF-1α）, leading to stabilisation of HIF-1α, heterodimerization with HIF-1 beta subunit（HIF-1β） and subsequent activation of HIF-1 pathway. Apical periodontitis（periapical lesion） is a consequence of endodontic infection and ultimately results in destruction of tooth-supporting tissue, including alveolar bone. Thus far, the role of HIF-1 in periapical lesions has not been systematically examined. In the present study, we determined the role of HIF-1 in a wellcharacterised mouse periapical lesion model using two HIF-1α-activating strategies, dimethyloxalylglycine（DMOG） and adenovirusinduced constitutively active HIF-1α（CA-HIF1 A）. Both DMOG and CA-HIF1 A attenuated periapical inflammation and tissue destruction. The attenuation in vivo was associated with downregulation of nuclear factor-κappa B（NF-κB） and osteoclastic gene expressions. These two agents also suppressed NF-κB activation and subsequent production of proinflammatory cytokines by macrophages. Furthermore, activation of HIF-1α by DMOG specifically suppressed lipopolysaccharide-stimulated macrophage differentiation into M1 cells, increasing the ratio of M2 macrophages against M1 cells. Taken together, our data indicated that activation of HIF-1 plays a protective role in the development of apical periodontitis via downregulation of NF-κB, proinflammatory cytokines, M1 macrophages and osteoclastogenesis.

Effects of hypoxia-inducible factor-1α silencing on the proliferation of CBRH-7919 hepatoma cells

AIM:To study the effects of hypoxia-inducible factor1α(HIF-1α) silencing on the proliferation of hypoxic CBRH-7919 rat hepatoma cells.METHODS:The CBRH-7919 rat hepatoma cell line was used in this study and the hypoxic model was constructed using CoCl2.The HIF-1α-specific RNAi sequences were designed according to the gene coding sequence of rat HIF-1α obtained from GeneBank.The secondary structure of the HIF-1α gene sequence was analyzed using RNA draw software.The small interfering RNA(siRNA) transfection mixture was produced by mixing the siRNA and Lipofectamine2000TM,and transfected into the hypoxic hepatoma cells.Real time reverse transcription-polymerase chain reaction(RTPCR) and Western blotting assay were used to detect the expression levels of mRNA and protein.HIF-1α and vascular endothelial growth factor(VEGF) mRNA was determined using real time RT-PCR;the protein expression levels of AKT,p-AKT,p21 and cyclinD1 were determined using Western blotting.The proliferation of hepatoma cells was observed using the methyl thiazolyl tetrazolium(MTT) assay and the bromodeoxyuridine(BrdU) incorporation cell proliferation assay.RESULTS:Under induced hypoxia,the viability of the hepatoma cells reached a minimum at 800 μmol/L CoCl2;the viability of the cells was relatively high at CoCl2 concentrations between 100 μmol/L and 200 μmol/L.Under hypoxia,the mRNA and protein expression levels of HIF-1α and VEGF were significantly higher than that of hepatoma cells that were cultured in normaxia.HIF-1α-specific RNAi sequences were successfully transfected into hepatoma cells.The transfection of specific siRNAs significantly inhibited the mRNA and protein expression levels of HIF-1α and VEGF,along with the protein expression levels of p-AKT and cyclinD1;the protein expression of p21 was significantly increased,and there was no significant difference in the expression of AKT.The MTT assay showed that the amount of hepatoma cells in S phase in the siRNA transfection group was obviously smaller than that in the control group;in the siRNA transfection group,the amount of hepatoma cells in G1 phase was more than that in the control group.The BrdU incorporation assay showed that the number of BrdU positive hepatoma cells in the siRNA transfection group was less than that in the control group.The data of the MTT assay and BrdU incorporation assay suggested that HIF-1α silencing using siRNAs significantly inhibited the proliferation of hepatoma cells.CONCLUSION:Hypoxia increases the expression of HIF-1α,and HIF-1α silencing significantly inhibits the proliferation of hypoxic CBRH-7919 rat hepatoma cells.

Early expressions of hypoxia-inducible factor 1alpha and vascular endothelial growth factor increase the neuronal plasticity of activated endogenous neural stem cells after focal cerebral ischemia

Endogenous neural stem cells become ＂activated＂ after neuronal injury, but the activation sequence and fate of endogenous neural stem cells in focal cerebral ischemia model are little known. We evaluated the relationships between neural stem cells and hypoxia-inducible factor-1α and vascular endothelial growth factor expression in a photothromobotic rat stroke model using immunohistochemistry and western blot analysis. We also evaluated the chronological changes of neural stem cells by 5-bromo-2′-deoxyuridine（BrdU） incorporation. Hypoxia-inducible factor-1α expression was initially increased from 1 hour after ischemic injury, followed by vascular endothelial growth factor expression. Hypoxia-inducible factor-1α immunoreactivity was detected in the ipsilateral cortical neurons of the infarct core and peri-infarct area. Vascular endothelial growth factor immunoreactivity was detected in bilateral cortex, but ipsilateral cortex staining intensity and numbers were greater than the contralateral cortex. Vascular endothelial growth factor immunoreactive cells were easily found along the peri-infarct area 12 hours after focal cerebral ischemia. The expression of nestin increased throughout the microvasculature in the ischemic core and the peri-infarct area in all experimental rats after 24 hours of ischemic injury. Nestin immunoreactivity increased in the subventricular zone during 12 hours to 3 days, and prominently increased in the ipsilateral cortex between 3–7 days. Nestin-labeled cells showed dual differentiation with microvessels near the infarct core and reactive astrocytes in the peri-infarct area. BrdU-labeled cells were increased gradually from day 1 in the ipsilateral subventricular zone and cortex, and numerous BrdU-labeled cells were observed in the peri-infarct area and non-lesioned cortex at 3 days. BrdU-labeled cells rather than neurons, were mainly co-labeled with nestin and GFAP. Early expressions of hypoxia-inducible factor-1α and vascular endothelial growth factor after ischemia made up the microenvironment to increase the neuronal plasticity of activated endogenous neural stem cells. Moreover, neural precursor cells after large-scale cortical injury could be recruited from the cortex nearby infarct core and subventricular zone.

The hypoxia-inducible factor-1α activates ectopic production of fibroblast growth factor 23 in tumor-induced osteomalacia

Tumor-induced osteomalacia （TIO） is a rare paraneoplastic syndrome in which ectopic production of fibroblast growth factor 23 （FGF23） by non-malignant mesenchymal tumors causes phosphate wasting and bone fractures. Recent studies have implicated the hypoxia-inducible factor-la （HIF-la） in other phosphate wasting disorders caused by elevated FGF23, including X-linked hypophosphatemic rickets and autosomal dominant hypophosphatemia. Here we provide evidence that HIF-la mediates aberrant FGF23 in TIO by transcriptionally activating its promoter. Immunohistochemical studies in phosphaturic mesenchymal tumors resected from patients with documented TIO showed that HIF-la and FGF23 were co-localized in spindle- shaped cells adjacent to blood vessels. Cultured tumor tissue produced high levels of intact FGF23 and demonstrated increased expression of HIF-la protein. Transfection of MC3T3-E1 and Saos-2 cells with a HIF-la expression construct induced the activity of a FGF23 reporter construct. Prior treatment of tumor organ cultures with HIF-la inhibitors decreased HIF-la and FGF23 protein accumulation and inhibited HIF-la-induced luciferase reporter activity in transfected cells. Chromatin immunoprecipitation assays confirmed binding to a HIF-la consensus sequence within the proximal FGF23 promoter, which was eliminated by treatment with a HIF-la inhibitor. These results show for the first time that HIF-la is a direct transcriptional activator of FGF23 and suggest that upregulation of HIF-la activity in TIO contributes to the aberrant FGF23 production in these patients.

Lysyl oxidase and hypoxia-inducible factor 1α: biomarkers of gastric cancer

BACKGROUND Gastric cancer(GC) is one of the main causes of cancer mortality worldwide.Recent studies on tumor microenvironments have shown that tumor metabolism exerts a vital role in cancer progression.AIM To investigate whether lysyl oxidase(LOX) and hypoxia-inducible factor 1α(HIF1α) are prognostic and predictive biomarkers in GC.METHODS A total of 80 tissue and blood samples were collected from 140 patients admitted to our hospital between August 2008 and March 2012. Immunohistochemical staining was performed to measure the expression of LOX and HIF1α in tumor and adjacent tissues collected from patients with GC. Real-time quantitative reverse transcription polymerase chain reaction(qRT-PCR) analysis was used to detect the mRNA expression levels of LOX and HIF1α in patients with GC. In addition, single-factor analysis was applied to analyze the relationship between LOX, HIF1α and prognosis of GC.RESULTS Immunohistochemical staining suggested that the expression levels of LOX and HIF1α increased in tumor tissues from patients with GC. QRT-PCR analysis indicated that mRNA expression of LOX and HIF1α was also upregulated in tumor tissues, which was in accordance with the above results. We also detected expression of these two genes in blood samples. The expression level of LOX and HIF1α was higher in patients with GC than in healthy controls. Additional analysis showed that the expression level of LOX and HIF1α was related to the clinicopathological characteristics of GC. Expression of LOX and HIF1α increased with the number of lymph node metastases, deeper infiltration depth and later tumor–node–metastasis stages. Single-factor analysis showed that high expression of LOX and HIF1α led to poor prognosis of patients with GC.CONCLUSION LOX and HIF1α can be used as prognostic and predictive biomarkers for GC.

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.

Extracellular vesicles from hypoxia-preconditioned mesenchymal stem cells alleviates myocardial injury by targeting thioredoxininteracting protein-mediated hypoxia-inducible factor-1αpathway

BACKGROUND Extracellular vesicles(EVs)derived from hypoxia-preconditioned(HP)mesenchymal stem cells(MSCs)have better cardioprotective effects against myocardial infarction(MI)in the early stage than EVs isolated from normoxic(NC)-MSCs.However,the cardioprotective mechanisms of HP-EVs are not fully understood.AIM To explore the cardioprotective mechanism of EVs derived from HP MSCs.METHODS We evaluated the cardioprotective effects of HP-EVs or NC-EVs from mouse adipose-derived MSCs(ADSCs)following hypoxia in vitro or MI in vivo,in order to improve the survival of cardiomyocytes(CMs)and restore cardiac function.The degree of CM apoptosis in each group was assessed by the terminal deoxynucleotidyl transferase dUTP nick end-labeling and Annexin V/PI assays.MicroRNA(miRNA)sequencing was used to investigate the functional RNA diversity between HP-EVs and NC-EVs from mouse ADSCs.The molecular mechanism of EVs in mediating thioredoxin-interacting protein(TXNIP)was verified by the dual-luciferase reporter assay.Co-immunoprecipitation,western blotting,and immunofluorescence were performed to determine if TXNIP is involved in hypoxia-inducible factor-1 alpha(HIF-1α)ubiquitination and degradation via the chromosomal region maintenance-1(CRM-1)-dependent nuclear transport pathway.RESULTS HP-EVs derived from MSCs reduced both infarct size(necrosis area)and apoptotic degree to a greater extent than NC-EVs from CMs subjected to hypoxia in vitro and mice with MI in vivo.Sequencing of EV-associated miRNAs showed the upregulation of 10 miRNAs predicted to bind TXNIP,an oxidative stress-associated protein.We showed miRNA224-5p,the most upregulated miRNA in HP-EVs,directly combined the 3’untranslated region of TXNIP and demonstrated its critical protective role against hypoxia-mediated CM injury.Our results demonstrated that MI triggered TXNIP-mediated HIF-1αubiquitination and degradation in the CRM-1-mediated nuclear transport pathway in CMs,which led to aggravated injury and hypoxia tolerance in CMs in the early stage of MI.CONCLUSION The anti-apoptotic effects of HP-EVs in alleviating MI and the hypoxic conditions of CMs until reperfusion therapy may partly result from EV miR-224-5p targeting TXNIP.

Clinicopathological and Prognostic Significance of Hypoxia-inducible Factor-1 alpha in Lung Cancer: a Systematic Review with Meta-analysis

Hypoxia-inducible factor-1 alpha（HIF-1α） plays a vital role in the initiation, evaluation and prognosis in lung cancer. The prognostic value of HIF-1α reported in diverse study remains disputable. Accordingly, a meta-analysis was implemented to further understand the prognostic role of HIF-1α in lung cancer. The relationship between HIF-1α and the clinicopathological characteristics and prognosis of lung cancer were investigated by a meta-analysis. Pub Med and Embase were searched from their inception to January 2015 for observational studies. Fixed-effects or random-effects meta-analyses were used to calculate odds ratios and 95% confidence intervals of different comparisons. A total of 20 studies met the criteria. The results showed that HIF-1α expression in lung cancer tissues was significantly higher than that in normal lung tissues. Expression of HIF-1α in patients with squamous cell carcinoma was significantly higher than that of patients with adenocarcinomas. Similarly, non-small cell lung cancer（NSCLC） patients had higher HIF-1α expression than small cell lung cancer（SCLC） patients. Moreover, lymph node metastasized tissues had higher HIF-1α expression than non-lymph node metastasized tissues. A high level HIF-1α expression was well correlated with the expression of vascular endothelial growth factor and epidermal growth factor receptor in the NSCLC. Notably, NSCLC or SCLC patients with positive HIF-1α expression in tumor tissues had lower overall survival rate than patients with negative HIF-1α expression. It was suggested that HIF-1α expression may be a prognostic biomarker and a potential therapeutic target for lung cancer.

“手十二井穴”放血预处理对大鼠急性低氧肺组织损伤模型血气、HIF-1α及VEGF水平的影响

目的 观察“手十二井穴”放血预处理对大鼠急性低氧肺组织损伤模型血气相关指标、低氧诱导因子(HIF)-1α及血管内皮细胞生长因子(VEGF)表达的影响,探讨“手十二井穴”放血预处理对急性低氧肺组织损伤的影响。方法 将72只雄性SD大鼠随机分为对照组8只、低氧(模型)组32只、井穴放血预处理(放血)组32只,模型组和放血组又分为6、24、48、72 h 4个时间段亚组,每组各8只。采用实验动物低氧模拟舱模拟15%O_(2)浓度,制备大鼠急性低氧肺组织损伤模型。放血组按“少商”“商阳”“中冲”“关冲”“少冲”“少泽”的顺序,每天1次,共5 d。用手持式血气分析仪检测肺动脉血气氧分压(PaO_(2))、血氧饱和度(SaO_(2))、酸碱度(pH)、二氧化碳分压(PaCO_(2))等相关指标,采用Western印迹法检测HIF-1α表达,酶联免疫吸附试验(ELISA)法检测VEGF含量。结果 与对照组比较,模型组各时间段PaO_(2)、SaO_(2)明显降低,HIF-1α和VEGF表达水平显著升高(P<0.01)。与同时间段模型组比较,放血组PaO_(2)和SaO_(2)均出现升高,PaO_(2)在6、48 h时有统计学意义,SaO_(2)值在6、24、48 h时有统计学意义(P<0.05,P<0.01),HIF-1α表达在各时段明显下调,VEGF含量在24、48、72 h时明显下降(P<0.05,P<0.01)。但放血组PaO_(2)各时间段和SaO_(2)(6、24 h)仍低于对照组,HIF-1α(6、48、72 h)和VEGF各时间段表达水平仍高于对照组,差异有统计学意义(P<0.05,P<0.01)。结论 “手十二井穴”放血预处理在一定时间和程度上可改善大鼠急性低氧(15%O_(2),85%N_(2))肺组织损伤模型的缺氧情况,其可能的作用与升高动脉血PaO_(2)、SaO_(2)及下调HIF-1α表达、降低VEGF含量有关,从而有利于模型大鼠适应急性低氧环境。

Hypoxia-inducible factor-1α–mediated upregulation of CD99 promotes the proliferation of placental mesenchymal stem cells by regulating ERK1/2

BACKGROUND As human placenta-derived mesenchymal stem cells(hP-MSCs)exist in a physiologically hypoxic microenvironment,various studies have focused on the influence of hypoxia.However,the underlying mechanisms remain to be further explored.AIM The aim was to reveal the possible mechanisms by which hypoxia enhances the proliferation of hP-MSCs.METHODS A hypoxic cell incubator(2.5%O2)was used to mimic a hypoxic microenvironment.Cell counting kit-8 and 5-ethynyl-20-deoxyuridine incorporation assays were used to assay the proliferation of hP-MSCs.The cell cycle was profiled by flow cytometry.Transcriptome profiling of hP-MSCs under hypoxia was performed by RNA sequencing.CD99 mRNA expression was assayed by reverse transcription-polymerase chain reaction.Small interfering RNA-mediated hypoxia-inducible factor 1α(HIF-1α)or CD99 knockdown of hP-MSCs,luciferase reporter assays,and the ERK1/2 signaling inhibitor PD98059 were used in the mechanistic analysis.Protein expression was assayed by western blotting;immunofluorescence assays were conducted to evaluate changes in expression levels.RESULTS Hypoxia enhanced hP-MSC proliferation,increased the expression of cyclin E1,cyclin-dependent kinase 2,and cyclin A2,and decreased the expression of p21.Under hypoxia,CD99 expression was increased by HIF-1α.CD99-specific small interfering RNA or the ERK1/2 signaling inhibitor PD98059 abrogated the hypoxia-induced increase in cell proliferation.CONCLUSION Hypoxia promoted hP-MSCs proliferation in a manner dependent on CD99 regulation of the MAPK/ERK signaling pathway in vitro.

紫草素调节HIF-1α/NLRP3信号通路对蛛网膜下腔出血大鼠神经功能损伤的影响

目的探究紫草素调节缺氧诱导因子-1α(HIF-1α)/NOD样受体热蛋白结构域相关蛋白3(NLRP3)信号通路对蛛网膜下腔出血(SAH)大鼠神经功能损伤的影响。方法大鼠随机分为假手术组、模型组、YC-1(HIF-1α抑制剂,5 mg/kg)组、紫草素低剂量组(4 mg/kg)、紫草素高剂量组(25 mg/kg)、紫草素高剂量(25 mg/kg)+AG1(HIF-1α激活剂,10 mg/kg)组,每组15只。采用颈内动脉刺破法制备SAH模型。采用Zea-Longa评分法评估6组大鼠神经功能;ELISA法检测血清肿瘤坏死因子α(TNF-α)、白介素-6(IL-6)和IL-1β水平;HE染色观察大鼠海马组织形态学变化,TUNEL染色法检测海马神经元凋亡率;伊文思蓝染色检测血脑屏障通透性;商品化试剂盒检测大鼠脑组织超氧化物歧化酶(SOD)、过氧化氢酶(MDA)、丙二醛(CAT)水平,Western blot检测大鼠脑组织Bax、Bcl-2、HIF-1α、NLRP3蛋白表达。结果假手术组大鼠海马神经元形态结构正常;与假手术组相比,模型组大鼠海马神经元有大量水肿、结构模糊,有细胞核溶解,变型固缩,部分细胞核消失,大鼠神经功能评分、血清TNF-α、IL-6和IL-1β水平、海马神经元凋亡率、伊文思蓝渗出量、脑组织MDA水平、Bax、HIF-1α、NLRP3水平显著增加,脑组织SOD、CAT水平、Bcl-2蛋白水平显著降低(P<0.05);与模型组比较,紫草素低剂量组、紫草素高剂量组和YC-1组鼠海马神经元病理损伤显著改善,大鼠神经功能评分、血清TNF-α、IL-6和IL-1β水平、海马神经元凋亡率、伊文思蓝渗出量、脑组织MDA水平、Bax、HIF-1α、NLRP3水平显著降低,SOD、CAT水平、Bcl-2蛋白水平显著升高(P<0.05);与紫草素高剂量组比较,紫草素高剂量+AG1组大鼠海马神经元病理损伤显著加重,大鼠神经功能评分、血清TNF-α、IL-6和IL-1β水平、海马神经元凋亡率、伊文思蓝渗出量、脑组织MDA水平、Bax、HIF-1α、NLRP3水平显著增加,SOD、CAT水平、Bcl-2蛋白水平显著降低(P<0.05)。结论紫草素抑制HIF-1α/NLRP3信号通路以降低氧化应激和炎性反应,进而改善SAH大鼠神经功能损伤。

熊果酸介导HIF-1α缓解木质化鸡胸肉发生的潜在作用机制研究

木质化鸡胸肉在快大型白羽肉鸡的胸肌组织中病变率高达20%,严重降低消费者的购买欲,也不利于后期加工,造成的经济损失相对较高。缺氧是导致木质化鸡胸肉发生的重要原因,缺氧诱导因子1α(HIF-1α)是机体缺氧状态下调节细胞功能的关键因子,缺氧会造成HIF-1α过表达,导致机体氧化应激、糖代谢紊乱和炎症反应的发生,进而导致快大型白羽肉鸡罹患木质化鸡胸肉。熊果酸具有抗氧化、抗炎和调节糖代谢等功效,并可通过腺苷酸激活蛋白激酶(AMPK)、磷脂酰肌醇3激酶/蛋白激酶B(PI3K/Akt)等信号通路调节HIF-1α在机体中的表达。作者综述了缺氧所导致的木质化鸡胸肉的发病机理以及熊果酸调控HIF-1α对氧化应激、糖代谢和炎症反应的影响,进一步分析了熊果酸通过AMPK、PI3K/Akt等信号通路调控HIF-1α缓解木质化鸡胸肉发生的潜在作用机制。

腰椎间盘突出伴坐骨神经痛患者血清HIF-1α、VEGFA水平与痛阈值关系及交互作用

目的探讨腰椎间盘突出伴坐骨神经痛(LDHS)患者血清缺氧诱导因子-1α(HIF-1α)、血管内皮生长因子A(VEGFA)水平与痛阈值的关系及交互作用。方法选取2020年5月至2023年2月在本院就诊的126例LDHS患者作为病例组,另选取同期126例体检健康者作为对照组。比较两组血清HIF-1α、VEGFA水平、痛阈值,Pearson相关系数分析血清HIF-1α、VEGFA水平与痛阈值的关系,多元线性回归分析血清HIF-1α、VEGFA水平与LDHS患者痛阈值的关系及交互作用。结果病例组血清HIF-1α、VEGFA水平高于对照组,痛阈值低于对照组(P<0.05)。病例组血清HIF-1α(r=0.777,P<0.001)、VEGFA(r=0.822,P<0.001)水平与痛阈值呈中度正相关,对照组血清HIF-1α(r=0.383,P<0.001)、VEGFA(r=0.453,P<0.001)水平与痛阈值无明显相关性。不考虑交互作用,血清HIF-1α、VEGFA水平与痛阈值存在线性相关(P<0.05),拟合方程为Y=-0.409+0.004×HIF-1α+0.019×VEGFA,所有预测变量可解释因变量的74.3%的方差。考虑交互作用,痛阈值的拟合方程为Y=19.276+0.062×HIF-1α+0.047×VEGFA-0×HIF-1α×VEGFA,所有预测变量可解释因变量的74.7%的方差,VEGFA低表达时,HIF-1α表达与痛阈值的关系较强,当VEGFA高表达时,HIF-1α与痛阈值的关系减弱,直线趋于平缓。结论血清HIF-1α、VEGFA水平与LDHS患者痛阈值关系密切,在对痛阈值影响中具有交互作用。

Effect of β-sodium aescinate on hypoxia-inducible factor-1α expression in rat brain cortex after cardiopulmonary resuscitation

BACKGROUND:This study was undertaken to investigate the expression of hypoxia-inducible factor-1a(HIF-1a) in rat cerebral cortex and the effects of p-sodium aescinate(SA) administration after return of spontaneous circulation(ROSC).METHODS:Sixty rats were divided into three groups:SA group,injected intraperitoneally with SA instantly after ROSC;control group,injected intraperitoneally with normal saline;and shamoperated group,without cardiac arrest or SA.The cardiac arrest model was established using asphyxiation and intravenous potassium chloride.Blood was sampled 1,6,12,and 24 hours after ROSC.Protein and mRNA levels of HIF-1a,VEGF and EPO were detected in the cerebral cortex by immunohistochemistry and real-time RT-PCR;serum levels of NSE and S100 P were determined by enzyme-linked immunosorbent assays.RESULTS:Serum S100β and NSE were significantly increased in the control group versus the sham-operated group 1,6,12 and 24 hours after ROSC(P<0.05).Protein and mRNA levels of HIF-1a,VEGF and EPO were significantly increased in the control rats(P<0.05).Serum NSE and S100 P were significantly decreased in the SA group versus the control group 1,6,12 and 24 hours after ROSC(P<0.05).Protein and mRNA levels of HIF-1a,VEGF and EPO were significantly increased in the SA group(P<0.05).CONCLUSIONS:The expression of HIF-1a is increased in rat cerebral cortex after ROSC,and SA up-regulates the expression of HIF-1α.The up-regulation of HIF-1α improves the resistance of the cortex to ischemia and hypoxia and contributes to neuroprotection,possibly because of up-regulation of EPO and VEGF expression.

HIFs in hypoxic regulation of the extracellular matrix:focus on little-known player HIF-3

The structural and associated molecules of the extracellular matrix(ECM)complex is an important component of the local milieu of cells,both for maintaining their functions and homeostasis.It is a dynamic structure that is finely tuned to changes in the microenvironment.One of these factors is hypoxia,which can arise in tissues due to physiological or pathological effects.As a result of the hypoxic effect,the properties of the ECM are significantly modified,stiffness increases,the balance between degradation and synthesis of structural proteins shifts,and the deposition of biologically active mediators’changes.Hypoxia-inducible factors(HIFs)contribute significantly to the modification of the properties of the ECM under hypoxia.Among the three HIF isoforms,HIF-1 is the most studied,with numerous identified target genes encoding proteins that participate in all matrisome compartments.Much less is known about HIF-2 and HIF-3.In the context of the effects of hypoxia on the matrisome,HIF-3 isoform is of particular interest.Unlike the first two isoforms,transiently expressed during the first hours of hypoxia,HIF-3 is activated after around 24 h of exposure to hypoxia and persists for a longer period.In addition,its transcription is more pronounced under hypoxia than are HIFs 1 and 2.HIF-3,rather than the first two isoforms,is possibly responsible for the changes that occur in matrisome during prolonged hypoxic conditions.This review attempts to summarize the available data on the involvement of HIF-3 in the matrisome modification under hypoxia.

肾小管HIF-1α/miR-23a通路在脓毒血症急性肾损伤中的作用机制

目的探讨肾小管低氧诱导因子-1α(HIF-1α)/MicroRNA-23a(miR-23a)通路在脓毒血症急性肾损伤(SA-AKI)中的作用及相关作用机制。方法体外培养人近曲小管上皮细胞(HK-2细胞),采用脂多糖(LPS)处理HK-2细胞构建SA-AKI细胞模型。LPS处理的HK-2细胞分为LPS组、NC siRNA组、HIF-1αsiRNA组、anti-miR-NC组、anti-miR-23a组、HIF-1αsiRNA+miR-NC组、HIF-1αsiRNA+miR-23a组,以正常培养的HK-2细胞作为空白对照组(Control组)。采用qRT-PCR法检测细胞中HIF-1α、miR-23a基因表达;CCK-8法检测细胞活力;流式细胞术检测细胞凋亡;ELISA法检测细胞中炎性因子[白介素-1β(IL-1β)、白介素-6(IL-6)、肿瘤坏死因子α(TNF-α)]水平;Western blot法检测细胞中HIF-1α蛋白、NF-κB通路蛋白表达。结果与Control组比较,LPS组HK-2细胞中HIF-1α蛋白和mRNA表达水平、miR-23a mRNA表达水平均升高,细胞活力降低,细胞凋亡率、细胞中IL-6、IL-1β和TNF-α水平均升高(P<0.05)。与LPS组比较,HIF-1αsiRNA组HK-2细胞中HIF-1α蛋白和mRNA表达水平、miR-23a mRNA表达水平均降低,细胞活力升高,细胞凋亡率、细胞中IL-6、IL-1β和TNF-α水平均降低(P<0.05)。与LPS组比较,anti-miR-23a组HK-2细胞中miR-23a mRNA表达水平降低,细胞活力升高,细胞凋亡率、细胞中IL-6、IL-1β和TNF-α水平均降低(P<0.05)。与HIF-1αsiRNA组比较,HIF-1αsiRNA+miR-23a组HK-2细胞中miR-23a mRNA表达水平升高,细胞活力降低,细胞凋亡率、细胞中IL-6、IL-1β和TNF-α水平均升高(P<0.05)。与Control组比较,LPS组HK-2细胞p-NF-κB-p65/NF-κB-p65、p-IκBα/IκBα比值均升高(P<0.05)。与LPS组比较,HIF-1αsiRNA组和anti-miR-23a组HK-2细胞p-NF-κB-p65/NF-κB-p65、p-IκBα/IκBα比值均降低(P<0.05)。与HIF-1αsiRNA组比较,HIF-1αsiRNA+miR-23a组HK-2细胞p-NF-κB-p65/NF-κB-p65、p-IκBα/IκBα比值均升高(P<0.05)。结论肾小管HIF-1α通过调控miR-23a表达调节NF-κB信号通路,从而参与LPS诱导的肾小管上皮细胞损伤。

Increased hypoxia-inducible factor 1alpha expression in rat brain tissues in response to aging

The present study observed changes in rat neural cells at various ages （3, 18, 24, and 30 months）. With age, neural cells became large and were sparsely arranged, and the number of Nissl bodies decreased. In addition, hypoxia-inducible factor 1α expression increased with increasing age in hippocampal CA1 and CA3 regions, motor cortex, and the first subfolium, especially from 3 to 18 months. In the open-field test, grid crossing decreased with increasing age, especially from 18 months. The number of rearings reached a peak in the 18 months group, and then subsequently decreased. The results suggested that hypoxia-inducible factor 1α played an important role in the nervous system aging process.