HIF-1α Expression Research Articles

Hypoxia drives estrogen receptor β-mediated cell growth via transcription activation in non-small cell lung cancer.

Non-small cell lung cancer (NSCLC) is a highly malignant tumor with a poor prognosis. Hypoxia conditions affect multiple cellular processes promoting the adaptation and progression of cancer cells via the activation of hypoxia-inducible factors (HIF) and subsequent transcription activation of their target genes. Preliminary studies have suggested that estrogen receptor β (ERβ) might play a promoting role in the progression of NSCLC. However, the precise mechanisms, particularly its connection to HIF-1α-mediated modulation under hypoxia, remain unclear. Our findings demonstrated that the overexpression of ERβ, not ERα, increased cell proliferation and inhibition of apoptosis in NSCLC cells and xenografts. Tissue microarray staining revealed a strong correlation between the protein expression of HIF-1α and ERβ. HIF-1α induced ERβ gene transcription and protein expression in CoCl2-induced hypoxia, 1% O2 incubation, or HIF-1α overexpressing cells. ChIP identified HIF-1α binding to a hypoxia response element in the ESR2 promoter. The suppression of HIF-1α and ERβ both in vitro and in vivo effectively reduced the tumor growth, thus emphasizing the promising prospects of targeting HIF-1α and ERβ as a therapeutic approach for the treatment of NSCLC. KEY MESSAGES: ERβ, not ERα, increases cell proliferation and inhibition of apoptosis in NSCLC cells and xenografts. A strong correlation exists between the protein expression of HIF-1α and ERβ. HIF-1α induced ERβ gene transcription and protein expression in hypoxic cells via binding to HRE in the ESR2 promoter. The suppression of HIF-1α and ERβ both in vitro and in vivo effectively reduced the NSCLC tumor growth.

Olig2+/NG2+/BLBP+ astrocyte progenitors: a novel component of the neurovascular unit in the developing mouse hippocampus.

Astrocytes are key components of the neurovascular unit. While we have recently identified Olig2+ astrocyte progenitors (ASPs) in the developing mouse dentate gyrus (DG), their molecular signature remains incompletely characterized. Here we demonstrate that Olig2+ ASPs predominantly express brain lipid-binding protein (BLBP), while only a small population of them expresses gfap-GFP. These Olig2+/BLBP+ ASPs co-express the transcription factors Sox3, Sox9 and the proteoglycan NG2 but not Sox10, a marker for oligodendrocyte progenitors (OLPs). Olig2+ ASPs appear from embryonic day 18 (E18) onwards and decline at postnatal day 14 (P14). Consistent with the proliferation of both Olig2+ and NG2+ glial cells after brain injury, intrauterine intermittent hypoxia (IH) led to an increase in Olig2+/NG2+/BLBP+ ASPs in the postnatal DG. IH also promoted both angiogenesis and vascular coupling of Olig2+/NG2+ ASPs. Our data suggest that IH-induced expression of HIF1a increases Olig2+/NG2+/BLBP+ ASPs in a cell non-autonomous manner. Our data also revealed increased vascular coupling of GFAP+ astrocytes following IH, while the number of GFAP+ astrocytes remains unchanged. Given that BLBP, Olig2 and NG2 are expressed in reactive astrocytes, our findings suggest that Olig2+/NG2+/BLBP+ ASPs represent a subtype of reactive astrocyte progenitors. Furthermore, the enhanced vascular coupling of Olig2+/NG2+/BLBP+ ASPs appears to be an adaptive response to hypoxic brain injury. This study provides new insights into the molecular characteristics of Olig2+/NG2+/BLBP+ ASPs and their potential role in the brain's response to hypoxic injury, contributing to our understanding of neurovascular unit dynamics in both development and pathological conditions.

Identifying HIF1A and HGF as two hub genes in aortic dissection and function analysis by integrating RNA sequencing and single-cell RNA sequencing data.

Aortic dissection (AD) is a severe aortic disease with high mortality, and its pathogenesis remains elusive. To explore the regulatory mechanisms of AD, we integrated public RNA sequencing (RNA-seq) and single-cell RNA sequencing (scRNA-seq) datasets to screen the hub genes of AD and further analyzed their functions, which may provide references to the diagnosis and treatment of AD. Four AD-related datasets were obtained from the Gene Expression Omnibus (GEO) database. Weighted gene co-expression network analysis and differential expression analysis were applied to identify overlapping genes in dataset GSE153434. Protein-protein interaction (PPI) network was constructed based on overlapping genes. Five methods (closeness, degree, EPC, MCC, and MNN) were used to pick hub genes. The receiver operating characteristic curve was used to evaluate the diagnostic efficiency of the hub genes in extra datasets GSE98770 and GSE52093. scRNA-seq dataset GSE213740 was used to explore the expression and function of the hub genes at the single-cell level. Quantitative real-time polymerase chain reaction was used to verify the expression of hub genes in beta-aminopropionitrile (BAPN)-induced mouse thoracic aortic aneurysm and dissection (TAAD) model. A total of 71 overlapping genes were screened by intersecting the significant genes in the pink module and the differentially expressed genes. A PPI network with 45 nodes and 74 edges was generated, and five top hub genes (HIF1A, HGF, HMOX1, ITGA5, and ITGB3) were identified. All the hub genes had area under the curve values above 0.55. scRNA-seq data analysis showed that HIF1A was significantly upregulated in macrophages and HGF was significantly upregulated in vascular smooth muscle cells (SMCs) of the ascending aortas in AD patients. HIF1A may transcriptionally regulate multiple downstream target genes involving inflammation (TLR2, ALOX5AP, and MIF), glycolysis (ENO1, LDHA, and GAPDH), tissue remodeling (PLAU), and angiogenesis (SERPIN and VEGFA). HGF may participate in the signaling among SMCs, fibroblasts, and endothelial cells through binding to different receptors (MET, EGFR, IGF1R, and KDR). The mRNA expression of Hif1a, Hgf, and their target genes, including Alox5ap, Serpine1, Tlr2, Plau, Egfr, and Igf1r, was significantly upregulated in aortic tissues of BAPN-treated mice. By integrating RNA-seq and scRNA-seq data, we identified HIF1A and HGF as two hub genes with good diagnostic efficiency for AD. HIF1A in macrophages may promote AD formation by promoting inflammation, glycolysis, tissue remodeling, and angiogenesis, and HGF may mediate signaling among SMCs, fibroblasts, and endothelial cells in the development of AD.

In Vitro Investigation of HIF-1α as a Therapeutic Target for Thyroid-Associated Ophthalmopathy.

Thyroid-associated ophthalmopathy (TAO) involves tissue expansion and inflammation, potentially causing a hypoxic microenvironment. Hypoxia-inducible factor (HIF)-1α is crucial in fibrosis and adipogenesis, which are observed in TAO progression. We investigated the effects of hypoxia on orbital fibroblasts (OFs) in TAO, focusing on the role of HIF-1α in TAO progression. OFs were isolated from TAO and non-TAO patients (as controls). In addition to HIF-1α, adipogenic differentiation markers including peroxisome proliferator-activated receptor γ (PPARγ) and CCAAT/enhancer binding protein (CEBP) were measured by Western blot, and phenotype changes were evaluated by Oil Red O staining under both normoxia and hypoxia. To elucidate the effect of HIF-1α inhibition, protein expression changes after HIF-1α inhibitor treatment were evaluated under normoxia and hypoxia. TAO OFs exhibited significantly higher HIF-1α expression than non-TAO OFs, and the difference was more distinct under hypoxia than under normoxia. Oil Red O staining showed that adipogenic differentiation of TAO OFs was prominent under hypoxia. Hypoxic conditions increased the expression of adipogenic markers, namely PPARγ and CEBP, as well as HIF-1α in TAO OFs. Interleukin 6 levels also increased in response to hypoxia. The effect of hypoxia on adipogenesis was reduced at the protein level after HIF-1α inhibitor treatment, and this inhibitory effect was sustained even with IGF-1 stimulation in addition to hypoxia. Hypoxia induces tissue remodeling in TAO by stimulating adipogenesis through HIF-1α activation. These data could provide insights into new treatment strategies and the mechanisms of adipose tissue remodeling in TAO.

Pilot Study on the Effect of Patient Condition and Clinical Parameters on Hypoxia-Induced Factor Expression: HIF1A, EPAS1 and HIF3A in Human Colostrum Cells.

Hypoxia-inducible factor 1 (HIF-1) may play a role in mammary gland development, milk production and secretion in mammals. Due to the limited number of scientific reports on the expression of HIF genes in colostrum cells, it was decided to examine the expression of HIF1A, HIF3A and EPAS1 in the these cells, collected from 35 patients who voluntarily agreed to provide their biological material for research, were informed about the purpose of the study and signed a consent to participate in it. The expression of HIF genes was assessed using qPCR. Additionally, the influence of clinical parameters (method of delivery, occurrence of stillbirths in previous pregnancies, BMI level before pregnancy and at the moment of delivery, presence of hypertension during pregnancy, presence of Escherichia coli in vaginal culture, iron supplement and heparin intake during pregnancy) on the gene expression was assessed, revealing statistically significant correlations. The expression of HIF1A was 3.5-fold higher in the case of patients with the presence of E. coli in vaginal culture (p = 0.041) and 2.5 times higher (p = 0.031) in samples from women who used heparin during pregnancy. Approximately 1.7-fold higher expression of the EPAS1 was observed in women who did not supplement iron during pregnancy (p = 0.046). To our knowledge, these are the first studies showing the relationship between HIF expression in cells from breast milk and the method of delivery and health condition of women giving birth. The assessment of HIF expression requires deeper examination in a larger study group, and the results of further studies will allow to determine whether HIF can become biomarkers in pregnancy pathology states.

Unveiling the proteome of the fasting heart: Insights into HIF-1 pathway regulation.

Fasting is a common dietary intervention known for its protective effects against metabolic and cardiovascular diseases. While its effects are mostly systemic, understanding tissue-specific changes in the heart is crucial for the identification of the mechanisms underlying fasting-induced cardioprotection. In this study, we performed a proteomic analysis of the fasting heart and attempted to clarify the molecular basis of fasting-induced cardioprotection. Our investigation identified a total of 4,652 proteins, with 127 exhibiting downregulation and 118 showing upregulation after fasting. Annotation analysis highlighted significant changes in processes such as lipid metabolism, the peroxisome pathway, and reactive oxygen species metabolism. Notably, the HIF-1 signaling pathway emerged as one of the focal points, with various HIF-1 targets exhibiting differential responses to fasting. Further experiments demonstrated downregulation of HIF-1α at both transcript and protein levels. Intriguingly, while gene expression of Egln3 decreased, its protein product PHD3 remained unaffected by fasting. The unchanged levels of pro-inflammatory cytokines indicated that the observed reduction in Hif1a expression did not stem from a decrease in basal inflammation. These findings underscore the complex regulation of the well-established cardioprotective HIF-1 signaling within the heart during 3-day fasting.

Plasmodium infection downregulates hypoxia‑inducible factor 1α expression to suppress the vascularization and tumorigenesis of liver cancer.

Liver cancer is characterized by hypervascularization. Anti-angiogenic agents may normalize the tumor vasculature and improve the efficacy of other treatments. The present study aims to investigate the anti-angiogenic effect of Plasmodium infection in a mouse model of implanted liver cancer cells. HepG2 cells were injected into the left liver lobe of nude mice as a model of in situ hepatic tumorigenesis. Plasmodium yoelii parasitized erythrocytes were administered in the animal model of liver cancer to introduce Plasmodium infection. The tumor growth and microvascular density were determined in the presence or absence of Plasmodium infection. The expression levels of hypoxia-inducible factor 1α (HIF-1α) and angiogenesis-related factors were evaluated using western blotting and reverse transcription-quantitative PCR analysis. The results demonstrated that Plasmodium infection suppressed tumor growth and vascularization in the mouse model of implanted HepG2 cells. Plasmodium parasites reduced the expression of pro-angiogenic factors (vascular endothelial growth factor A and angiopoietin 2), matrix metalloproteinases [(MMP)2 and MMP9] and inflammatory cytokines [tumor necrosis factor α, interleukin 6 (IL)-6) and IL-1β] in both hepatic and tumor tissues. HIF-1α was downregulated in both hepatic and tumor tissues upon Plasmodium infection, and HIF-1α overexpression rescued angiogenesis and tumor growth under the condition of Plasmodium infection. In conclusion, the results of the present study demonstrated the anti-angiogenic and anti-tumorigenic effects of Plasmodium infection on liver cancer through downregulating HIF-1α expression, indicating that Plasmodium parasites could be developed as an intervention strategy to restrain neo-angiogenesis in liver cancer.

PAARH promotes M2 macrophage polarization and immune evasion of liver cancer cells through VEGF protein

ObjectiveThis study aims to investigate the mechanism by which PAARH promotes M2 macrophage polarization and immune evasion of liver cancer cells through VEGF, in order to reveal its role in the progression of liver cancer. MethodsThe expressions of PAARH, VEGF, and HIF-1α in liver cancer cells were detected using qRT-PCR and Western blot. Flow cytometry was utilized to analyze the polarization status of macrophages and assess the impact on immune evasion-related markers. The relationship between PAARH and VEGF in macrophage polarization was further explored. Additionally, a tumor-bearing mouse model was established to observe tumor growth. ResultsThe results show that PAARH is upregulated in liver cancer cells, and silencing PAARH significantly inhibits tumor malignancy progression. Under hypoxic conditions, overexpression of PAARH significantly increases VEGF expression, and PAARH regulates M2 macrophage polarization through VEGF. Overexpression of PAARH significantly promotes M2 macrophage polarization, increases levels of PD-L1 and Th2 immune response markers, and enhances cell proliferation, migration, and invasion; it also suppresses M1 macrophage polarization, decreases levels of PD-L2 and Th1 immune response markers, and inhibits cell apoptosis. Silencing VEGF reverses these effects. Silencing PAARH or overexpressing VEGF weakens the malignant phenotype of the cells and immune evasion. Results from the tumor-bearing mouse model indicate that silencing PAARH significantly reduces tumor size and weight, while overexpressing VEGF significantly increases tumor volume and weight. ConclusionPAARH enhances the immune evasion capability of liver cancer cells by upregulating VEGF to promote M2 macrophage polarization, suggesting that PAARH may serve as a new therapeutic target for liver cancer.

Therapeutic effect of bloodletting on bone deterioration induced by hypobaric hypoxia in young rats

ObjectivesHigh-altitude regions, comprising hypoxic conditions, are associated with different altitude-induced pathologies, including a reduction in bone density. Elucidating the mechanisms underlying bone degradation in such environments and developing targeted interventions and therapeutics is important. Bloodletting therapy has promising clinical applications, but its effects on the skeletal system and bone homeostasis are not well understood. The aim of this study was to investigate the effects of a hypobaric hypoxia environment on specific femoral morphological and structural properties, including bone volume, cortical thickness, and trabecular microarchitecture, in juvenile Sprague–Dawley (SD) rats, and to explore the potential modulating effects of a bloodletting intervention on these parameters. MethodsMale SD rats, 6 weeks of age, were subjected to a simulated hypobaric hypoxia environment, replicating a 5000-m altitude, for 12 weeks. For the bloodletting intervention group, rats were subjected to a weekly 500 μL tail vein blood withdrawal. Micro-CT technology, hematoxylin and eosin staining, and tartrate-resistant acid phosphatase staining were employed to comprehensively assess the femoral microstructure, tissue architecture, and cellular morphology. Additionally, immunofluorescence analysis was conducted to quantify the expression of key proteins, and transcriptome analysis was performed to identify differentially expressed genes. ResultsExposure of rats to hypobaric hypoxia led to a significant reduction in bone mineral content, trabecular bone number, and cortical bone thickness, suggesting a deterioration of bone microstructure. Additionally, the hypoxic environment upregulated the expression of RANKL and HIF-1α, while downregulating RUNX2. Notably, although bloodletting intervention did not significantly reverse these bone structural changes, transcriptome analysis revealed its regulatory influence on the expression of key genes, particularly Mmp2, Fosl2, and URS0000B2A65A, which are implicated in pathways governing the hypoxic response, osteoclast differentiation, and PI3K–Akt signaling. ConclusionThis study highlights the detrimental effect of hypobaric hypoxia on the bone microstructure of juvenile rats and underscores the therapeutic potential of bloodletting to ameliorate this condition. Additionally, our study on the regulatory mechanisms mediating bloodletting's effects on gene expression offers fresh perspectives on bone alterations. It suggests promising avenues for the development of novel preventative measures and targeted therapies to address the challenges posed by related bone disorders.

AAV-mediated combination gene therapy of inducible Caspase 9 and miR-199a-5p is therapeutic in hepatocellular carcinoma.

Advanced-stage hepatocellular carcinoma (HCC) remains an untreatable disease with an overall survival of less than one year. One of the critical molecular mediators contributing to increased resistance to therapy and relapse, is increased hypoxia-inducible factor 1α (HIF-1α) levels, leading to metastasis of tumor cells. Several microRNAs are known to be dysregulated and impact HIF-1α expression in HCC. An in silico analysis demonstrated that hsa-miR-199a-5p is downregulated at various stages of HCC and is known to repress HIF-1α expression. Based on this analysis, we developed a combinatorial suicide gene therapy by employing hepatotropic Adeno-associated virus-based vectors encoding an inducible caspase 9 (iCasp9) and miR-199a. The overexpression of miR-199a-5p alone significantly decreased ( ~ 2-fold vs. Mock treated cells, p < 0.05) HIF-1α mRNA levels, with a concomitant increase in cancer cell cytotoxicity in Huh7 cells in vitro and in xenograft models in vivo. To further enhance the efficacy of gene therapy, we evaluated the synergistic therapeutic effect of AAV8-miR-199a and AAV6-iCasp9 in a xenograft model of HCC. Our data revealed that mice receiving combination suicide gene therapy exhibited reduced expression of HIF-1α ( ~ 4-fold vs. Mock, p < 0.001), with a significant reduction in tumor growth when compared to mock-treated animals. These findings underscore the therapeutic potential of downregulating HIF-1α during suicide gene therapy for HCC.

Anticancer potential of isoalantolactone in testicular cancer: an analysis of cytotoxicity, apoptosis, and signaling pathways.

Testicular cancer, a highly prevalent malignancy among young adults, has witnessed an alarming rise in recent decades. This study delves into the therapeutic potential of isoalantolactone (IATL), a natural product extracted from Inula helenium and Inula racemosa, against testicular cancer. Employing MTT assays and flow cytometry, we observed a dose-dependent reduction in cell viability and induction of cell cycle arrest at sub-G1 phase with increasing IATL concentrations. Furthermore, Annexin V/PI dual staining revealed IATL-induced apoptosis. Human Apoptosis Array analysis demonstrated IATL's influence on HIF-1α and TNF R1 expression, implicating its role in cancer cell growth and death regulation. Next-generation sequencing (NGS) and pathway analysis highlighted the involvement of ferroptosis and HIF-1 signaling in IATL-mediated effects. Western blotting validated the downregulation of key proteins associated with apoptosis inhibition and activation, confirming IATL's potential as an anticancer agent. Moreover, IATL induced ferroptosis by modulating expression levels of GPX4, xCT, NRF2, and HO-1. Our findings shed light on IATL's multifaceted anticancer mechanisms, emphasizing its potential as a therapeutic candidate for testicular cancer.

Shikonin induces ferroptosis in osteosarcomas through the mitochondrial ROS-regulated HIF-1α/HO-1 axis

BackgroundThe most common malignant bone tumour is osteosarcoma, which has an unsatisfactory prognosis and unsatisfactory treatment. Ferroptosis shows promise as an effective OS therapy. A substance extracted from the Lithospermum erythrorhizon, Shikonin (SHK), inhibits a number of tumours, including ovarian, gastric, and lung cancers. However, whether SHK induces OS ferroptosis and its mechanisms are not clear. PurposeOur study is aimed at investigating whether SHK causes ferroptosis and elucidating its molecular mechanism. MethodsCell counting Kit-8, cell cycle and cell apoptosis assay were utilised to assess therapeutic effect of SHK against OS. Normal cells, including H9C2, AML-12 and HK-2, haematoxylin and eosin staining and mice serum biomarker tests were used to assess SHK biosafety. Malondialdehyde (MDA) levels, the glutathione (GSH)/oxidized glutathione (GSSG) ratio, reactive oxygen species (ROS), lipid peroxide (LPO), and intracellular Fe2+ detection, quantitative reverse transcription PCR (qRT-PCR), Western blotting (WB) and rescue experiments were employed to confirm whether SHK induced ferroptosis in OS cells. Molecular docking, cellular thermal shift assay (CETSA), and drug affinity responsive target stability (DARTS) assay were used to evaluate the direct binding between SHK and hypoxia-inducible factor-1α (HIF-1α). Protein stability and degradation analysis, small RNA interference, flow cytometry, qRT-PCR, and WB were used to investigate the molecular mechanism of ferroptosis. In vivo xenografts of nude mouse was used to study the anti-OS effect of SHK. ResultsSHK significantly reduced OS cell viability and induced apoptosis and G2/M arrest. SHK increased intracellular levels of MDA, ROS, LPO, and Fe2+ while simultaneously reducing the GSH/GSSG ratio and GPX4 and SLC7A11 expression. CETSA and DARTS results demonstrated that SHK did not bind targetly to HIF-1α. Instead, mitochondrial ROS (MitoROS) promoted HIF-1α expression, resulting in HO-1 overexpression, excess Fe2+ production, ROS accumulation and GPX depletion, and ferroptosis. Furthermore, inhibition of MitoROS using Mito-TEMPO downregulated HIF-1α/HO-1 axis and mitigated the SHK-induced ferroptosis. In vivo, SHK effectively suppressed OS growth with favourable biosafety, confirming the molecular mechanism underlying SHK-induced ferroptosis in OS. ConclusionWe observe that HIF-1α/HO-1 axis is the crucial factor in SHK-induced OS ferroptosis. Importantly, we demonstrate that HIF-1α is indirectly regulated by MitoROS rather than SHK bound directly to HIF-1α. Our research suggest that SHK is a potential drug candidate for OS treatment and may help in identifying novel therapeutic targets for OS.

Ling gui shen fu decoction ameliorates cardiac injury in ischemic heart disease rats by regulating ANP32A/HIF2α/HMGB1 signal route

Purpose: To investigate the effect of ling gui shen fu decoction (LGSFD) on cardiac injury and cardiomyocyte apoptosis in rats with ischemic heart disease (IHD), and to elucidate the underlying molecular mechanism. Methods: An IHD rat model was established by performing coronary artery occlusion surgery on the left anterior descending (LAD) of rats. The rats were assigned equally to 5 groups: sham-operated group (sham group), IHD group, IHD + perindopril group, IHD + low- dose LGSFD group (IHD + LGSFD-L group), and IHD + high-dose LGSFD group (IHD+LGSFD-H group). The LGSFD was given via gavage. A hypoxia-induced cardiomyocyte model was established by subjecting H9C2 cells to hypoxia. Then, LGSFD-containing serum or blank serum was used to treat the hypoxic rat cardiomyocytes (H9C2). The severity of cardiac injury and extent of apoptotic changes in cardiomyocytes was determined using hematoxylin-eosin (H&amp;E) staining and TUNEL staining, while immunoblotting was used to measure the protein expressions of ANP32A, p-AKT, AKT, HIF-2α, p-mTOR, mTOR and HMGB1. Results: The cardiac injury of rats in the LGSFD groups was significantly reversed, relative to the IHD group (p &lt; 0.05). Moreover, LGSFD reduced the level of apoptosis in hypoxia- induced H9C2 cells and upregulated the concentrations of ANP32A, p-AKT, HIF-2α and p-mTOR. However, the expression levels of HMGB1 were decreased in the heart tissues of IHD rats and hypoxic H9C2 cells. Silencing of ANP32A with ANP32A siRNA (siANP32A) down- regulated ANP32A, p-AKT, HIF-2α and p-mTOR, but up-regulated apoptosis and expression levels of HMGB1 in hypoxic H9C2 cells. Conclusion: LGSFD ameliorates cardiac injury in IHD rats by inhibiting cardiomyocyte apoptosis via the ANP32A/HIF-2α/HMGB1 axis. Further investigations are recommended into the specific mechanism of LGSFD effect using clinical samples, in order to facilitate its clinical development.

USP26 Combats Age-Related Declines in Self-Renewal and Multipotent Differentiation of BMSC by Maintaining Mitochondrial Homeostasis.

Age-related declines in self-renewal and multipotency of bone marrow mesenchymal stem cells (BMSCs) limit their applications in tissue engineering and clinical therapy. Thus, understanding the mechanisms behind BMSC senescence is crucial for maintaining the rejuvenation and multipotent differentiation capabilities of BMSCs. This study reveals that impaired USP26 expression in BMSCs leads to mitochondrial dysfunction, ultimately resulting in aging and age-related declines in the self-renewal and multipotency of BMSCs. Specifically, decreased USP26 expression results in decreased protein levels of Sirtuin 2 due to its ubiquitination degradation, which leads to mitochondrial dysfunction in BMSCs and ultimately resulting in aging and age-related declines in self-renewal and multilineage differentiation potentials. Additionally, decreased USP26 expression in aging BMSCs is a result of dampened hypoxia-inducible factor 1α (HIF-1α) expression. HIF-1α facilitates USP26 transcriptional expression by increasing USP26 promoter activity through binding to the -191 - -198 bp and -262 - -269 bp regions on the USP26 promoter. Therefore, the identification of USP26 as being correlated with aging and age-related declines in self-renewal and multipotency of BMSCs, along with understanding its expression and action mechanisms, suggests that USP26 represents a novel therapeutic target for combating aging and age-related declines in the self-renewal and multipotent differentiation of BMSCs.

Hypoxia-Induced Inflammation in In Vitro Model of Human Blood-Brain Barrier: Modulatory Effects of the Olfactory Ensheathing Cell-Conditioned Medium.

Hypoxia compromises the integrity of the blood-brain barrier (BBB) and increases its permeability, thereby inducing inflammation. Olfactory ensheathing cells (OECs) garnered considerable interest due to their neuroregenerative and anti-inflammatory properties. Here, we aimed to investigate the potential modulatory effects of OEC-conditioned medium (OEC-CM) on the response of human brain microvascular endothelial cells (HBMECs), constituting the BBB, when exposed to hypoxia. HBMECs were utilized to establish the in vitro BBB model. OECs were isolated from mouse olfactory bulbs, and OEC-CM was collected after 48h of culture. The effect of OEC-CM treatment on the HBMEC viability was evaluated under both normoxic and hypoxic conditions at 6h, 24h, and 30h. Western blot and immunostaining techniques were employed to assess NF-κB/phospho-NF-κB expression. HIF-1α, VEGF-A, and cPLA2 mRNA expression levels were quantified using digital PCR. ELISA assays were performed to measure PGE2, VEGF-A, IL-8 secretion, and cPLA2 specific activity. The in vitro formation of HBMEC capillary-like structures was examined using a three-dimensional matrix system. OEC-CM attenuated pro-inflammatory responses and mitigated the HIF-1α/VEGFA signaling pathway activation in HBMECs under hypoxic condition. Hypoxia-induced damage of the BBB can be mitigated by novel therapeutic strategies harnessing OEC potential.

Taurine reduces glycolysis of pig skeletal muscle by inhibiting HIF-1α signaling.

The aim of this study was to investigate the effect of taurine on skeletal muscle glycolysis in pigs. The results showed that dietary supplementation of taurine significantly reduced the activities of hexokinase (HK), phosphofructose kinase (PFK), and pyruvate kinase (PK) in finishing pigs. Meanwhile, taurine reduced the protein and mRNA expression levels of hypoxia inducible factor 1α (HIF-1α) and the mRNA expression of glycolytic enzyme related genes (such as HK type II, HK Ⅱ; pyruvate kinase M2, PKM2; lactate dehydrogenase A, LDHA). In addition, taurine reduced the expression of HIF-1α, lactate content, and the expression of glycolysis related genes in porcine myotubes. These results suggest that taurine may regulate glycolysis in skeletal muscle of finishing pigs through the HIF-1α signaling pathway. To further investigate the mechanism by which taurine affects skeletal glycolysis, HIF-1α activator dimethyloxalyl glycine (DMOG) was used to treat porcine myotubes, our results showed that DMOG significantly increased the protein and mRNA expression levels of HIF-1α, lactate content, and glycolytic enzyme (HK, PFK, PK, and LDH) activity, but taurine treatment significantly inhibited this effect. Taken together, these results of in vivo and in vitro experiments revealed that taurine reduces skeletal muscle glycolysis by inhibiting HIF-1α signaling.

Aquaporin-1 Facilitates Macrophage M1 Polarization by Enhancing Glycolysis Through the Activation of HIF1α in Lipopolysaccharide-Induced Acute Kidney Injury.

This study aimed to investigate how aquaporin 1 (AQP1) modulates hypoxia-inducible factor-1α (HIF1α) to promote glycolysis and drive the M1 polarization of macrophages. Within 12 h post-treatment with LPS to induce acute kidney injury in rats, a significant upregulation of AQP1 and HIF1α protein levels was noted in serum and kidney tissues. This elevation corresponded with a decrease in blood glucose concentrations and an enhancement of glycolytic activity relative to the control group. Furthermore, there was a pronounced reduction in the circulating levels of the anti-inflammatory cytokine IL-10, accompanied by an upregulation in the levels of the pro-inflammatory cytokines IL-6 and TNF-α. The administration of an HIF1α inhibitor reversed these effects, which did not affect the production of AQP1 protein. In cellular assays, AQP1 knockdown mitigated the increase in HIF1α expression induced by LPS. Furthermore, the suppression of HIF1α with PX-478 led to decreased expression levels of Hexokinase 2 (HK2) and Lactate Dehydrogenase A (LDHA), indicating that AQP1 regulates glycolysis through HIF1α. M1 polarization of macrophages was reduced by AQP1 knockdown and was further diminished by the addition of an HIF1α inhibitor. Inhibition of the glycolytic process not only weakened M1 polarization but also promoted M2 polarization, thereby reducing the release of inflammatory cytokines. These findings provide a novel perspective for developing therapeutic strategies that target AQP1 and HIF1α, potentially improving the treatment of sepsis-associated AKI.

Fetal hypoxia exposure induced Hif1a activation and autophagy in adult ovary granulosa cells.

Environmental hypoxia adversely impacts the reproduction of humans and animals. Previously, we showed that fetal hypoxia exposure led to granulosa cell (GC) autophagic cell death via the Foxo1/Pi3k/Akt pathway. However, the upstream regulatory mechanisms underlying GC dysfunction remain largely unexplored. Here, we tested the hypothesis that fetal hypoxia exposure altered gene expression programs in adult GCs and impaired ovarian function. We established a fetal hypoxia model in which pregnant mice were maintained in a high-plateau hypoxic environment from gestation day (E) 0--16.5 to study the impact of hypoxia exposure on the ovarian development and subsequent fertility of offspring. Compared with the unexposed control, fetal hypoxia impaired fertility by disordering ovarian function. Specifically, fetal hypoxia caused mitochondrial dysfunction, oxidant stress and autophagy in GCs in the adult ovary. RNA-seq analysis revealed that 437 genes were differentially expressed in the adult GCs of exposed animals. Western blotting results also revealed that fetal exposure induced high levels of hypoxia-inducible factor 1-alpha (Hif1a) expression in adult GCs. We then treated GCs isolated from exposed mice with PX-478, a specific pharmacological inhibitor of Hif-1a, and found that autophagy and apoptosis were effectively alleviated. Finally, by using a human ovarian granulosa-like tumor cell line (KGN) to simulate hypoxia in vitro, we showed that Hif1a regulated autophagic cell death in GCs through the Pi3k/Akt pathway. Together, these findings suggest that fetal hypoxia exposure induced persistent Hif1a expression, which impaired mitochondrial function and led to autophagic cell death in the GCs of the adult ovary.

Whole transcription analysis identified the regulation of hypoxia-inducible factors in monocytes with immune suppression: implications for clinical outcomes.

Sepsis progression is marked by a complex immune response, where the involvement of hypoxia-inducible factors (HIF) plays an uncertain role. The study aims to elucidate the involvement of HIF-1α in monocyte function during sepsis and its potential as a prognostic indicator. Transcriptomic data from healthy individuals and septic patients in datasets GSE54514, GSE167363, and GSE46955 were analyzed. Additionally, human monocytes were employed to elucidate how HIF regulates immune responses in the context of sepsis. Septic non-survivors exhibited sustained upregulation of HIF-1α expression alongside compromised inflammatory response and antigen presentation, with downregulation of NF-κB and HLADRB1 genes associated with poor sepsis prognosis. Conversely, septic survivors displayed an increased proportion of classical monocytes and enhanced inflammation and expression of antigen presentation-related genes. During the recovery phase of sepsis, monocytes continued to demonstrate elevated HIF-1α expression. In cultured THP1 cells and septic CD14+ monocytes, HIF hindered inflammatory responses and antigen presentation, while also suppressing the proportion of classical monocytes after LPS stimulation. Mechanistically, HIF significantly attenuated LPS-induced immune responses in monocytes by inhibiting the phosphorylation of IKK. HIF in monocytes acts as a suppressor of immune-inflammatory responses and antigen presentation, and may serve as a negative molecular marker for sepsis development.

Macrophage migration inhibitory factor facilitates replication of Senecavirus A by enhancing the glycolysis via hypoxia inducible factor 1 alpha

Senecavirus A (SVA) induced porcine idiopathic vesicular disease (PIVD) has been spread worldwide due to persistent infection, causing economic losses in swine industry. Host factors play an important role in replication of SVA, while, the interaction of migration inhibitory factor (MIF) and the virus has not been verified. Here, MIF facilitates the replication of SVA by enhancing the glycolysis via hypoxia-inducible factor alpha (HIF-1α) was reported. SVA infection up-regulates the expression of MIF in 3D4/21 cells, and infection experiment of cells with overexpression and interference expression of MIF showed that MIF facilitates the replication of SVA. MIF promoted the glycolysis in SVA infection to facilitate its replication by enhancing the accumulation of lactate and decreasing the production of adenosine triphosphate (ATP) and inhibiting the expression of retinoic acid-inducible gene I (RIG-I), mitochondrial antiviral-signaling protein (MAVS), interferon regulatory factor 3 (IRF3), interferon-beta (IFN-β), IFN-α, interferon-stimulating gene 15 (ISG15), and ISG56. Meanwhile, specific inhibitor verified MIF facilitates the replication of SVA by enhancing glycolysis. Further results showed MIF induces the increased expression of HIF-1α, which enhances MIF-induced glycolysis. These results provide new data on host factors in replication of SVA, as well as better understanding the role of MIF in virus infection.