Aerobic glycolysis in colon cancer is repressed by naringin via the HIF1Α pathway / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

Metabolic reprogramming is a common phenomenon in cancer, with aerobic glycolysis being one of its important characteristics. Hypoxia-inducible factor-1α (HIF1Α) is thought to play an important role in aerobic glycolysis. Meanwhile, naringin is a natural flavanone glycoside derived from grapefruits and many other citrus fruits. In this work, we identified glycolytic genes related to HIF1Α by analyzing the colon cancer database. The analysis of extracellular acidification rate and cell function verified the regulatory effects of HIF1Α overexpression on glycolysis, and the proliferation and migration of colon cancer cells. Moreover, naringin was used as an inhibitor of colon cancer cells to illustrate its effect on HIF1Α function. The results showed that the HIF1Α and enolase 2 (ENO2) levels in colon cancer tissues were highly correlated, and their high expression indicated a poor prognosis for colon cancer patients. Mechanistically, HIF1Α directly binds to the DNA promoter region and upregulates the transcription of ENO2; ectopic expression of ENO2 increased aerobic glycolysis in colon cancer cells. Most importantly, we found that the appropriate concentration of naringin inhibited the transcriptional activity of HIF1Α, which in turn decreased aerobic glycolysis in colon cancer cells. Generally, naringin reduces glycolysis in colon cancer cells by reducing the transcriptional activity of HIF1Α and the proliferation and invasion of colon cancer cells. This study helps to elucidate the relationship between colon cancer progression and glucose metabolism, and demonstrates the efficacy of naringin in the treatment of colon cancer.

Targeting TRMT5 suppresses hepatocellular carcinoma progression via inhibiting the HIF-1α pathways / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

Accumulating evidence has confirmed the links between transfer RNA (tRNA) modifications and tumor progression. The present study is the first to explore the role of tRNA methyltransferase 5 (TRMT5), which catalyzes the m1G37 modification of mitochondrial tRNAs in hepatocellular carcinoma (HCC) progression. Here, based on bioinformatics and clinical analyses, we identified that TRMT5 expression was upregulated in HCC, which correlated with poor prognosis. Silencing TRMT5 attenuated HCC proliferation and metastasis both in vivo and in vitro, which may be partially explained by declined extracellular acidification rate (ECAR) and oxygen consumption rate (OCR). Mechanistically, we discovered that knockdown of TRMT5 inactivated the hypoxia-inducible factor-1 (HIF-1) signaling pathway by preventing HIF-1α stability through the enhancement of cellular oxygen content. Moreover, our data indicated that inhibition of TRMT5 sensitized HCC to doxorubicin by adjusting HIF-‍1α. In conclusion, our study revealed that targeting TRMT5 could inhibit HCC progression and increase the susceptibility of tumor cells to chemotherapy drugs. Thus, TRMT5 might be a carcinogenesis candidate gene that could serve as a potential target for HCC therapy.

Hypoxia-induced ROS aggravate tumor progression through HIF-1α-SERPINE1 signaling in glioblastoma / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

Hypoxia, as an important hallmark of the tumor microenvironment, is a major cause of oxidative stress and plays a central role in various malignant tumors, including glioblastoma. Elevated reactive oxygen species (ROS) in a hypoxic microenvironment promote glioblastoma progression; however, the underlying mechanism has not been clarified. Herein, we found that hypoxia promoted ROS production, and the proliferation, migration, and invasion of glioblastoma cells, while this promotion was restrained by ROS scavengers N-acetyl-L-cysteine (NAC) and diphenyleneiodonium chloride (DPI). Hypoxia-induced ROS activated hypoxia-inducible factor-1α (HIF-1α) signaling, which enhanced cell migration and invasion by epithelial-mesenchymal transition (EMT). Furthermore, the induction of serine protease inhibitor family E member 1 (SERPINE1) was ROS-dependent under hypoxia, and HIF-1α mediated SERPINE1 increase induced by ROS via binding to the SERPINE1 promoter region, thereby facilitating glioblastoma migration and invasion. Taken together, our data revealed that hypoxia-induced ROS reinforce the hypoxic adaptation of glioblastoma by driving the HIF-1α-SERPINE1 signaling pathway, and that targeting ROS may be a promising therapeutic strategy for glioblastoma.

Expression Changes of Hypoxia-Inducible Factor-1α in G-CSF Induced Hematopoietic Stem Cell Mobilization / 中国实验血液学杂志

OBJECTIVE@#To investigate the expression and its relative mechanism of hypoxia-inducible factor-1α(HIF-1α) in bone marrow(BM) of mice during G-CSF mobilization of hematopoietic stem cells (HSC) .@*METHODS@#Flow cytometry was used to detect the proportion of Lin-Sca-1+ c-kit+ (LSK) cells in peripheral blood of C57BL/6J mice before and after G-CSF mobilization. And the expression of HIF-1α and osteocalcin (OCN) mRNA and protein were detected by RQ-PCR and immunohistochemistry. The number of osteoblasts in bone marrow specimens of mice was counted under the microscope.@*RESULTS@#The proportion of LSK cells in peripheral blood began to increase at day 4 of G-CSF mobilization, and reached the peak at day 5, which was significantly higher than that of control group (P<0.05). There was no distinct difference in the expression of HIF-1α mRNA between bone marrow nucleated cells and osteoblasts of steady-state mice (P=0.073), while OCN mRNA was mainly expressed in osteoblasts, which was higher than that in bone marrow nucleated cells (P=0.034). After mobilization, the expression level of HIF-1α increased, but OCN decreased, and the number of endosteum osteoblasts decreased. The change of HIF-1α expression was later than that of OCN and was consistent with the proportion of LSK cells in peripheral blood.@*CONCLUSION@#The expression of HIF-1α in bone marrow was increased during the mobilization of HSC mediated by G-CSF, and one of the mechanisms may be related to the peripheral migration of HSC induced by osteoblasts inhibition.

CHD1 deletion stabilizes HIF1α to promote angiogenesis and glycolysis in prostate cancer / 亚洲男科学杂志(英文版)

Chromodomain-helicase-DNA-binding protein 1 (CHD1) deletion is among the most common mutations in prostate cancer (PCa), but its role remains unclear. In this study, RNA sequencing was conducted in PCa cells after clustered regularly interspaced palindromic repeat (CRISPR)/CRISPR-associated protein 9 (Cas9)-based CHD1 knockout. Gene set enrichment analysis (GSEA) indicated upregulation of hypoxia-related pathways. A subsequent study confirmed that CHD1 deletion significantly upregulated hypoxia-inducible factor 1α (HIF1α) expression. Mechanistic investigation revealed that CHD1 deletion upregulated HIF1α by transcriptionally downregulating prolyl hydroxylase domain protein 2 (PHD2), a prolyl hydroxylase catalyzing the hydroxylation of HIF1α and thus promoting its degradation by the E3 ligase von Hippel-Lindau tumor suppressor (VHL). Functional analysis showed that CHD1 deletion promoted angiogenesis and glycolysis, possibly through HIF1α target genes. Taken together, these findings indicate that CHD1 deletion enhances HIF1α expression through PHD2 downregulation and therefore promotes angiogenesis and metabolic reprogramming in PCa.

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

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

Danlou Tablet Improves Chronic Intermittent Hypoxia-Induced Dyslipidemia and Arteriosclerosis by HIF-1α-Angptl4 mRNA Signaling Pathway / 中国结合医学杂志

OBJECTIVE@#To detect whether Danlou Tablet (DLT) regulates the hypoxia-induced factor (HIF)-1α-angiopoietin-like 4 (Angptl4) mRNA signaling pathway and explore the role of DLT in treating chronic intermittent hypoxia (CIH)-induced dyslipidemia and arteriosclerosis.@*METHODS@#The mature adipocytes were obtained from 3T3-L1 cell culturation and allocated into 8 groups including control groups (Groups 1 and 5, 0.1 mL of cell culture grade water); DLT groups (Groups 2 and 6, 0.1 mL of 1,000 µg/mL DLT submicron powder solution); dimethyloxalylglycine (DMOG) groups (Groups 3 and 7, DMOG and 0.1 mL of cell culture grade water); DMOG plus DLT groups (Groups 4 and 8, DMOG and 0.1 mL of 1,000 µg/mL DLT submicron powder solution). Groups 1-4 used mature adipocytes and groups 5-8 used HIF-1 α-siRNA lentivirus-transfected mature adipocytes. After 24-h treatment, real-time polymerase chain reaction and Western blot were employed to determine the mRNA and protein expression levels of HIF-1 α and Angptl4. In animal experiments, the CIH model in ApoE-/- mice was established. Sixteen mice were complete randomly divided into 4 groups including sham group, CIH model group [intermittent hypoxia and normal saline (2 mL/time) gavage once a day]; Angptl4 Ab group [intermittent hypoxia and Angptl4 antibody (30 mg/kg) intraperitoneally injected every week]; DLT group [intermittent hypoxia and DLT (250 mg/kg) once a day], 4 mice in each group. After 4-week treatment, enzyme linked immunosorbent assay was used to detect the expression levels of serum total cholesterol (TC) and triglyceride (TG). Hematoxylin-eosin and CD68 staining were used to observe the morphological properties of arterial plaques.@*RESULTS@#Angptl4 expression was dependent on HIF-1 α, with a reduction in mRNA expression and no response in protein level to DMOG or DLT treatment in relation to siHIF-1 α -transfected cells. DLT inhibited HIF-1 α and Angptl4 mRNA expression (P<0.05 or P<0.01) and reduced HIF-1 α and Angptl4 protein expressions with DMOG in mature adipocytes (all P<0.01), as the effect on HIF-1 α protein also existed in the presence of siHIF-1 α (P<0.01). ApoE-/- mice treated with CIH had increased TG and TC levels (all P<0.01) and atherosclerotic plaque. Angptl4 antibody and DLT both reduce TG and TC levels (all P<0.01), as well as reducing atherosclerotic plaque areas, narrowing arterial wall thickness and alleviating atherosclerotic lesion symptoms to some extent.@*CONCLUSION@#DLT had positive effects in improving dyslipidemia and arteriosclerosis by inhibiting Angptl4 protein level through HIF-1 α-Angptl4 mRNA signaling pathway.

Yin-Yang-1 decreases Fas-induced apoptosis in acute lymphoblastic leukemia under hypoxic conditions: its implications in immune evasion / YY1 induce la disminución de la apoptosis a través de Fas en la leucemia linfoblástica aguda en condiciones hipóxicas: implicaciones en la evasión de la respuesta inmunitaria

Abstract Background: Acute lymphoblastic leukemia (ALL) is an aggressive malignant disease with high prevalence in pediatric patients. It has been shown that the downregulation of Fas expression is correlated with an inadequate response in ALL, although these mechanisms are still not well understood. Several reports demonstrated that hypoxia is involved in dysfunctional apoptosis. Yin-Yang-1 (YY1) transcription factor is involved in resistance to apoptosis, tumor progression, and it is increased in different types of cancer, including leukemia. The regulatory mechanism underlying YY1 expression in leukemia is still not understood, but it is known that YY1 negatively regulates Fas expression. The study aimed to evaluate the effect of YY1 on Fas expression under hypoxic conditions in ALL. Methods: Leukemia cell line RS4; 11 was cultured under normoxic and hypoxic conditions. YY1, Fas receptor, and hypoxia-inducible factor (HIF-1α) expression were analyzed. After treatment with a Fas agonist (DX2), apoptosis was analyzed through the detection of active caspase 3. Data were analyzed using Pearson’s correlation. Results: Leukemia cells co-expressed both HIF-1α and YY1 under hypoxia, which correlated with a downregulation of Fas expression. During hypoxia, the levels of apoptosis diminished after DX2 treatment. The analysis revealed that patients with high levels of HIF-1α also express high levels of YY1 and low levels of Fas. Conclusions: These results suggest that YY1 negatively regulates the expression of the Fas receptor, which could be involved in the escape of leukemic cells from the immune response contributing to the ALL pathogenesis.

Resumen Introducción: La leucemia linfoblástica aguda (LLA) es una enfermedad con alta prevalencia en la población pediátrica. El mecanismo por el cual el receptor de Fas participa en la regulación inmunitaria en los tumores es desconocido, pero se sabe que está subexpresado en LLA. El factor de transcripción Ying-Yang-1 (YY1) está involucrado en la resistencia a la apoptosis y la progresión tumoral; se encuentra aumentado en diferentes tumores, incluida la LLA. Aunque los mecanismos que regulan la expresión de YY1 en LLA son desconocidos, se sabe que YY1 regula la expresión del receptor de Fas. El objetivo de este trabajo fue evaluar el efecto de YY1 en la expresión de Fas en condiciones de hipoxia en la LLA. Métodos: Se cultivaron células RS4;11 en condiciones de hipoxia y se analizó la expresión de YY1, receptor de Fas y HIF-1α. La apoptosis fue inducida usando un agonista de Fas (DX2) y se analizó con la detección de caspasa 3 activa. Los datos se analizaron mediante correlación de Pearson. Resultados: Las células RS4;11 coexpresaron HIF-1αy YY1 en hipoxia, lo cual correlaciona con una baja expresión de Fas. La apoptosis se encontró disminuida durante condiciones de hipoxia, después del tratamiento con DX2. El análisis bioinformático mostró que los pacientes con altos niveles de HIF-1αpresentan YY1 elevado y bajos niveles del receptor de Fas. Conclusiones: Estos resultados sugieren que YY1 regula negativamente la expresión del receptor de Fas, lo cual podría estar involucrado en el escape de las células leucémicas a la respuesta inmunitaria, contribuyendo a la patogénesis de la LLA.

Hypoxia inducible factor-1 (HIF-1α) reduced inflammation in spinal cord injury via miR-380-3p/ NLRP3 by Circ 0001723

BACKGROUND: Spinal cord injury (SCI) is a severe central nervous system trauma. The present study aimed to evaluate the effect of HIF-1α on inflammation in spinal cord injury (SCI) to uncover the molecular mechanisms of anti-inflammation. RESULTS: HIF-1α was reduced in SCI model rats and HIF-1α activation reduced TNF-α, IL-1ß, IL-6 and IL-18 levels in SCI model rats. Meanwhile, Circ 0001723 expression was down-regulated and miR-380-3p expression was up-regulated in SCI model rats. In vitro model, down-regulation of Circ 0001723 promoted TNF-α, IL-1ß, IL-6 and IL-18 levels, compared with control negative group. However, over-expression of Circ 0001723 reduced TNF-α, IL-1ß, IL-6 and IL-18 levels in vitro model. Down-regulation of Circ 0001723 suppressed HIF-1α protein expressions and induced NLRP3 and Caspase-1 protein expressions in vitro model by up-regulation of miR-380-3p. Next, inactivation of HIF-1α reduced the pro-inflammation effects of Circ 0001723 in vitro model. Then, si-NLRP3 also inhibited the pro-inflammation effects of Circ 0001723 in vitro model via promotion of autophagy. CONCLUSIONS: We concluded that HIF-1α reduced inflammation in spinal cord injury via miR-380-3p/ NLRP3 by Circ 0001723.

Expression of hypoxia-inducible factor 1α is associated with lymph node metastasis in oral squamous cell carcinoma / 北京大学学报(医学版)

OBJECTIVE@#To explore the association between hypoxia-inducible factor 1α (HIF-1α) expression and lymph node metastasis in oral squamous cell carcinoma (OSCC).@*METHODS@#Tumor specimens from 125 patients with histologically-proven, surgically-treated OSCC were examined by immunohistochemical staining for expression of HIF-1α. The patients were divided into two groups by the expression of HIF-1α, high expression of HIF -1α group (H-group) and low expression of HIF-1α group (L-group). The main assessment parameters were lymph node metastasis rate and disease-specific survival (DSS). The lymph node metastasis rate and clinicopathologic features were compared using Mann-Whitney test. The Kaplan-Meier curve was generated for each group and compared using the log-rank test. Cox proportional hazard models were utilized for multivariate analyses of HIF-1α expression and other baseline factors with DSS. All calculations and analyses were performed using the SPSS 17.0 software package.@*RESULTS@#The protein expression levels of HIF-1α were up-regulated in OSCC and two patients were unable to evaluate. There were 48 patients in L-group and 75 patients in H-group. Lymph node metastasis rate was 37.5% (18/48) for L-group and 58.7% (44/75) for H-group (P=0.027). Expression of HIF-1α was significantly correlated with lymph node metastasis. The patients of L-group had a significantly better DSS than the patients of H-group (70.8% vs. 46.7%, P=0.005), while the patients of L-group had a significantly better disease-free survival (DFS) than the patients of H-group (60.4% vs. 36.0%, P=0.009) by Kaplan-Meier method. A multivariate survival analysis also showed that HIF-1α expression (HR=2.164, 95%CI: 1.150-4.074, P=0.017) and T-stage (HR=1.387, 95%CI: 1.066-1.804, P=0.015) both were the independent factors associated with prognosis.@*CONCLUSION@#HIF-1α expression is significantly correlated with lymph node metastasis in OSCC. HIF-1α expression is an independent predictive factor for prognosis of OSCC patients, and may serve as a potential biomarker for molecular diagnosis and targeted therapy in future.

Propranolol inhibits the proliferation, migration and tube formation of hemangioma cells through HIF-1α dependent mechanisms

The aim of this study was to investigate the mechanism of propranolol on the regression of hemangiomas. Propranolol-treated hemangioma tissues were collected and the expression of hypoxia inducible factor-1α (HIF-1α) was examined. We also established HIF-1α overexpression and knockdown hemangioma cells, and determined the effects of HIF-1α on the hemangioma cells proliferation, apoptosis, migration and tube formation. Significantly increased HIF-1α level was found in the hemangioma tissues compared to that in normal vascular tissues, whereas propranolol treatment decreased the HIF-1α level in hemangioma tissues in a time- and dose-dependent manner. Moreover, propranolol treatment significantly decreased cell proliferation, migration and tube formation as well as promoted cell apoptosis in HIF-1α overexpression and knockdown hemangioma cells. Propranolol suppressed the cells proliferation, migration and tube formation of hemangioma cells through HIF-1α dependent mechanisms. HIF-1α could serve as a novel target in the treatment of hemangiomas.

The Changes of HIF-1α and VEGF-A in Myocardial Tissue of Rats with Arrhythmias / 法医学杂志

OBJECTIVES@#To observe the expression changes of hypoxia inducible factor-1α（HIF-1α） and vascular endothelial growth factor-A （VEGF-A） in rats with arrhythmias, and to explore the differences of the expression pattern in the two indicators of acute myocardial ischemia caused by arrhythmias and coronary insufficiency.@*METHODS@#The arrhythmia was induced by CaCl₂, and the expression changes of HIF-1α and VEGF-A were detected by immunohistochemistry, Western blotting and real-time PCR within 6 h after the arrhythmia in rats.@*RESULTS@#The expression of HIF-1α and VEGF-A showed diffuse in the myocardial tissue of rats died from arrhythmias. Both of them increased in the early arrhythmia, then decreased. Extensive myocardial ischemia happened at the beginning of arrhythmia occurrence and its range didn't expand with time.@*CONCLUSIONS@#The expressions of HIF-1α and VEGF-A in myocardium of the rats with arrhythmia can provide evidence for the differential diagnosis of acute myocardial ischemia caused by fatal arrhythmia and coronary insufficiency.

Immunoexpression of HIF-1α and VEGF in Periodontal Disease and Healthy Gingival Tissues

Abstract Hypoxia-inducible factor 1 alpha (HIF-1α) and vascular endothelial growth factor (VEGF) are proteins that stimulate the proliferation and migration of endothelial cells. These proteins have been described in many pathologic and inflammatory conditions, but their involvement in the development of periodontitis has not been thoroughly investigated. This study compared the immunohistochemical expression of these proteins, involved in angiogenesis and hypoxia, by imunnostained inflammatory and endothelial cells in periodontal disease and healthy gingival tissues. Gingival tissue samples were divided as follows: 30 samples with chronic periodontitis, 30 with chronic gingivitis, and 30 of healthy gingiva. Results were analyzed statistically by the Kruskal-Wallis, Mann-Whitney and Spearman correlation tests (p=0.01). Inflammatory and endothelial cells were found to express these proteins. Periodontitis showed median percentage of HIF-1α-positive cells of 39.6%, 22.0% in cases of gingivitis and 0.9% in the healthy gingiva group (p=0.001). For VEGF, median percentage of immunopositive cells was 68.7% for periodontitis, 66.1% in cases for gingivitis, and 19.2% for healthy gingival specimens (p<0.001). Significant correlation between VEGF and HIF-1α was also observed in healthy gingiva (p<0.001).The increased expression of HIF-1αα and VEGF in periodontitis, compared to gingivitis and healthy gingiva, suggests possible activation of the HIF-1α pathway in advanced periodontal disease. The correlation between HIF-1α and VEGF expression in healthy gingiva suggests a physiological function for these proteins in conditions of homeostasis. In periodontal disease, HIF-1 and VEGF expression may be regulated by other factors, in addition to hypoxia, such as bacterial endotoxins and inflammatory cytokines.

Resumo O fator induzível por hipóxia 1 alfa (HIF-1α) e o fator de crescimento endotelial vascular (VEGF) são proteínas que estimulam a proliferação e a migração de células endoteliais. Estas proteínas têm sido descritas em muitas condições patológicas e inflamatórias, mas o envolvimento dessas no desenvolvimento de periodontite não foi completamente investigado. Este estudo comparou a expressão imunohistoquímica destas proteínas, envolvidas na angiogênese e hipóxia, na doença periodontal e em tecidos gengivais saudáveis por meio de contagem de células inflamatórias e endoteliais imunomarcadas. As amostras de tecido gengival foram divididas da seguinte forma: 30 amostras com periodontite crônica, 30 com gengivite crônica e 30 de gengiva saudável. Os resultados foram analisados estatisticamente pelos testes de Kruskal-Wallis e Mann-Whitney (p=0.01). As células inflamatórias e endoteliais foram positivas para estas proteínas. A porcentagem média de células positivas para HIF-1α foi de 39,6% nos casos de periodontite, 22,0% nos casos de gengivite e de 0,9% no grupo de gengiva saudável (p = 0,001). A porcentagem média de células imunopositivas para o VEGF foi de 68,7% nos casos de periodontite, 66,1% nos casos de gengivite, e 19,2% em espécimes gengivais saudáveis (p<0,001). Correlação significativa entre o VEGF e HIF-1α foi observada em gengival. A expressão elevada do HIF-1α e VEGF em periodontite, comparada a gengivite e gengiva saudável, sugere ativação da via do HIF-1α, na doença periodontal avançada. A correlação entre o HIF-1α e expressão de VEGF na gengiva saudável, sugere uma função fisiológica para estas proteínas em condições de homeostase. Na doença periodontal, a expressão de HIF-1α e VEGF pode ser regulada por outros fatores, além da hipóxia, tais como endotoxinas bacterianas e citocinas inflamatórias.

Effects of Omega-3 Fatty Acids on Erectile Dysfunction in a Rat Model of Atherosclerosis-induced Chronic Pelvic Ischemia

The aim of this study was to investigate whether the omega-3 fatty acids help to improve erectile function in an atherosclerosis-induced erectile dysfunction rat model. A total of 20 male Sprague-Dawley rats at age 8 weeks were divided into three groups: Control group (n = 6, untreated sham operated rats), Pathologic group (n = 7, untreated rats with chronic pelvic ischemia [CPI]), and Treatment group (n = 7, CPI rats treated with omega-3 fatty acids). For the in vivo study, electrical stimulation of the cavernosal nerve was performed and erectile function was measured in all groups. Immunohistochemical antibody staining was performed for transforming growth factor beta-1 (TGF-β1), endothelial nitric oxide synthase (eNOS), and hypoxia inducible factor 1-alpha (HIF-1α). In vivo measurement of erectile function in the Pathologic group showed significantly lower values than those in the Control group, whereas the Treatment group showed significantly improved values in comparison with those in the Pathologic group. The results of western blot analysis revealed that systemically administered omega-3 fatty acids ameliorated the cavernosal molecular environment. Our study suggests that omega-3 fatty acids improve intracavernosal pressure and have a beneficial role against pathophysiological consequences such as fibrosis or hypoxic damage on a CPI rat model, which represents a structural erectile dysfunction model.

Cardiac Ultrastructure and Changes of HSP70 and HIF-1α Expression in Electric Shock Death Rats / 法医学杂志

OBJECTIVE@#To observe cardiac ultrastructure and the expression of heat shock protein 70 (HSP70) and hypoxia inducible factor-lα (HIF-lα) in electric shock death rats and to explore the application of these indexes as the basis of medical identification in electric shock death.@*METHODS@#Seventy-two SD rats were randomly divided into electric shock death group, postmortem electric shock group and the control group. The changes of myocardial ultrastructure were observed by transmission electron microscope, and the expressions of myocardial HSP70 and HIF-1α were observed by immunohistochemical technology.@*RESULTS@#Myocardial myofibril fracture, mitochondrial cristae and membrane dissolution, and disordered arrangement of Z lines and M lines were observed in electric shock rats. HSP70 and HIF-lα were strong positive expressions in the electric shock death group, significantly compared with the control and postmortem electric shock groups (P < 0.05).@*CONCLUSION@#The expressions of HSP70 and HIF-lα were obviously increased in electric shock death group, which may be used as the diagnostic indicator of electric shock death.

The pleckstrin homology domain of phospholipase D1 accelerates EGFR endocytosis by increasing the expression of the Rab5 effector, rabaptin-5

Endocytosis is differentially regulated by hypoxia-inducible factor-1alpha (HIF-1alpha) and phospholipase D (PLD). However, the relationship between HIF-1alpha and PLD in endocytosis is unknown. HIF-1alpha is degraded through the prolyl hydroxylase (PHD)/von Hippel-Lindau (VHL) ubiquitination pathway in an oxygen-dependent manner. Here, we show that PLD1 recovers the decrease in epidermal growth factor receptor (EGFR) endocytosis induced by HIF-1alpha independent of lipase activity via the Rab5-mediated endosome fusion pathway. EGF-induced interaction of PLD1 with HIF-1alpha, PHD and VHL may contribute to EGFR endocytosis. The pleckstrin homology domain (PH) of PLD1 itself promotes degradation of HIF-1alpha, then accelerates EGFR endocytosis via upregulation of rabaptin-5 and suppresses tumor progression. These findings reveal a novel role of the PLD1-PH domain as a positive regulator of endocytosis and provide a link between PLD1 and HIF-1alpha in the EGFR endocytosis pathway.

Phospholipase D2 promotes degradation of hypoxia-inducible factor-1alpha independent of lipase activity

Hypoxia-inducible factor-1alpha (HIF-1alpha) is a key transcriptional mediator that coordinates the expression of various genes involved in tumorigenesis in response to changes in oxygen tension. The stability of HIF-1alpha protein is determined by oxygen-dependent prolyl hydroxylation, which is required for binding of the von Hippel-Lindau protein (VHL), the recognition component of an E3 ubiquitin ligase that targets HIF-1alpha for ubiquitination and degradation. Here, we demonstrate that PLD2 protein itself interacts with HIF-1alpha, prolyl hydroxylase (PHD) and VHL to promote degradation of HIF-1alpha via the proteasomal pathway independent of lipase activity. PLD2 increases PHD2-mediated hydroxylation of HIF-1alpha by increasing the interaction of HIF-1alpha with PHD2. Moreover, PLD2 promotes VHL-dependent HIF-1alpha degradation by accelerating the association between VHL and HIF-1alpha. The interaction of the pleckstrin homology domain of PLD2 with HIF-1alpha also promoted degradation of HIF-1alpha and decreased expression of its target genes. These results indicate that PLD2 negatively regulates the stability of HIF-1alpha through the dynamic assembly of HIF-1alpha, PHD2 and VHL.

Deferoxamine Improves Alveolar and Pulmonary Vascular Development by Upregulating Hypoxia-inducible Factor-1alpha in a Rat Model of Bronchopulmonary Dysplasia

Fetal lung development normally occurs in a hypoxic environment. Hypoxia-inducible factor (HIF)-1alpha is robustly induced under hypoxia and transactivates many genes that are essential for fetal development. Most preterm infants are prematurely exposed to hyperoxia, which can halt hypoxia-driven lung maturation. We were to investigate whether the HIF-1alpha inducer, deferoxamine (DFX) can improve alveolarization in a rat model of bronchopulmonary dysplasia (BPD). A rat model of BPD was produced by intra-amniotic lipopolysaccharide (LPS) administration and postnatal hyperoxia (85% for 7 days), and DFX (150 mg/kg/d) or vehicle was administered to rat pups intraperitoneally for 14 days. On day 14, the rat pups were sacrificed and their lungs were removed and examined. A parallel in vitro study was performed with a human small airway epithelial cell line to test whether DFX induces the expression of HIF-1alpha and its target genes. Alveolarization and pulmonary vascular development were impaired in rats with BPD. However, DFX significantly ameliorated these effects. Immunohistochemical analysis showed that HIF-1alpha was significantly upregulated in the lungs of BPD rats treated with DFX. DFX was also found to induce HIF-1alpha in human small airway epithelial cells and to promote the expression of HIF-1alpha target genes. Our data suggest that DFX induces and activates HIF-1alpha, thereby improving alveolarization and vascular distribution in the lungs of rats with BPD.

Nitric oxide ineerferes with hypoxia signaling during colonic inflamaation / A interferência do óxido nítrico na sinalização da hipóxia durante a inflamação colônica

Context Intestinal inflammation can induce a local reduction in oxygen levels that triggers an adaptive response centered on the expression of hypoxia-inducible factors (HIFs). Nitric oxide, a well-described inflammatory mediator, may interfere with hypoxia signaling. Objectives We aimed to evaluate the role of nitric oxide in hypoxia signaling during colonic inflammation. Methods Colitis was induced by single (acute) or repeated (reactivated colitis) trinitrobenzenosulfonic acid administration in rats. In addition, one group of rats with reactivated colitis was also treated with Nw-Nitro-L-arginine methyl ester hydrochloride to block nitric oxide synthase. Colitis was assessed by macroscopic score and myeloperoxidase activity in the colon samples. Hypoxia was determined using the oxygen-dependent probe, pimonidazole. The expression of HIF-1α and HIF-induced factors (vascular endothelial growth factor - VEGF and apelin) was assessed using Western blotting. Results The single or repeated administration of trinitrobenzenosulfonic acid to rats induced colitis which was characterized by a high macroscopic score and myeloperoxidase activity. Hypoxia was observed with both protocols. During acute colitis, HIF-1α expression was not increased, but VEGF and apelin were increased. HIF-1α expression was inhibited during reactivated colitis, and VEGF and apelin were not increased. Nw-Nitro-L-arginine methyl ester hydrochloride blockade during reactivated colitis restored HIF-1α, VEGF and apelin expression. Conclusions Nitric oxide could interfere with hypoxia signaling during reactivated colitis inflammation modifying the expression of proteins regulated by HIF-1α. .

Contexto A inflamação intestinal pode induzir uma redução local nos níveis de oxigênio e ativar uma resposta adaptativa relacionada à expressão de fatores induzíveis por hipóxia (HIFs). O óxido nítrico, um mediador inflamatório bem descrito, pode interferir com a sinalização de hipóxia. Objetivos O objetivo foi avaliar o papel do óxido nítrico na sinalização de hipóxia durante a inflamação colônica. Métodos A colite foi induzida em ratos pela administração única (aguda) ou repetida (com reativações) de ácido trinitrobenzenosulfônico. Adicionalmente, um grupo de ratos de colite com reativações foi também tratado com Nw-Nitro-L-arginina metil éster para inibir a óxido nítrico sintase. A colite foi avaliada através do escore macroscópico e da atividade de mieloperoxidase em amostras de cólon. A hipóxia foi determinada usando uma sonda dependente de oxigênio, o pimonidazol. A expressão de HIF-1α e de fatores induzidos pelo HIF (factor de crescimento endotelial vascular - VEGF e apelina) foi avaliada pela técnica de Western blotting. Resultados A administração única ou repetida de ácido trinitrobenzenosulfônico a ratos induziu colite que foi caracterizada por um alto escore macroscópico e alta atividade de mieloperoxidase. Hipóxia foi observada em ambos os protocolos. Durante a colite aguda, a expressão de HIF-1α não aumentou, enquanto a de VEGF e apelina aumentou. A expressão de HIF-1α esteve inibida durante a colite com reativações e, a expressão de VEGF e apelina não se modificou. O bloqueio com Nw-Nitro-L-arginina metil éster durante a colite com reativações restabeleceu a expressão de HIF-1α, VEGF e ...

Putative role of ischemic postconditioning in a rat model of limb ischemia and reperfusion: involvement of hypoxia-inducible factor-1? expression

Hypoxia-inducible factor-1α (HIF-1α) is one of the most potent angiogenic growth factors. It improves angiogenesis and tissue perfusion in ischemic skeletal muscle. In the present study, we tested the hypothesis that ischemic postconditioning is effective for salvaging ischemic skeletal muscle resulting from limb ischemia-reperfusion injury, and that the mechanism involves expression of HIF-1α. Wistar rats were randomly divided into three groups (n=36 each): sham-operated (group S), hindlimb ischemia-reperfusion (group IR), and ischemic postconditioning (group IPO). Each group was divided into subgroups (n=6) according to reperfusion time: immediate (0 h, T0), 1 h (T1), 3 h (T3), 6 h (T6), 12 h (T12), and 24 h (T24). In the IPO group, three cycles of 30-s reperfusion and 30-s femoral aortic reocclusion were carried out before reperfusion. At all reperfusion times (T0-T24), serum creatine kinase (CK) and lactate dehydrogenase (LDH) activities, as well as interleukin (IL)-6, IL-10, and tumor necrosis factor-α (TNF-α) concentrations, were measured in rats after they were killed. Histological and immunohistochemical methods were used to assess the skeletal muscle damage and HIF-1α expression in skeletal muscle ischemia. In groups IR and IPO, serum LDH and CK activities and TNF-α, IL-6, and IL-10 concentrations were all significantly increased compared to group S, and HIF-1α expression was up-regulated (P<0.05 or P<0.01). In group IPO, serum LDH and CK activities and TNF-α and IL-6 concentrations were significantly decreased, IL-10 concentration was increased, HlF-1α expression was down-regulated (P<0.05 or P<0.01), and the pathological changes were reduced compared to group IR. The present study suggests that ischemic postconditioning can reduce skeletal muscle damage caused by limb ischemia-reperfusion and that its mechanisms may be related to the involvement of HlF-1α in the limb ischemia-reperfusion injury-triggered inflammatory response.