Increased HIF-1α Expression Research Articles

Creatine supplementation in largemouth bass (Micropterus salmoides) diets: improving intestinal health and alleviating enteritis.

Creatine plays an important role in regulating intestinal epithelial cell energy metabolism, epithelial integrity, and intestinal barrier function. In this study, three feeds with varying creatine concentrations (0%, 0.5%, and 4%, labeled CR0, CR0.5, and CR4, respectively) were formulated and administered to juvenile largemouth bass (Micropterus salmoides) for 8 weeks. Creatine-containing diets significantly improved growth performance and intestinal villus height. Microbiota analysis revealed that creatine-containing diets changed the beta diversity of gut microbes and increased the relative proportion of Cetobacterium. Enteritis was induced for 7 days using the corresponding feeds containing creatine and 2% DSS (labeled CR0, DCR0, DCR0.5, and DCR4). Enteritis resulted in an increase in hif1α expression in the DCR0.5 and DCR4 groups and a significant increase expression of creatine transporter SLC6A8. QPCR and Western blotting of intestinal barrier-related genes (e.g., Claudin1, Claudin4, and ZO1), MUC2 immunohistochemistry, and PAS mucus staining were used to show intestinal barrier status, these results suggest that dietary creatine attenuates the extent of intestinal barrier damage. After TUNEL and KI67 immunofluorescence analyses of the intestine and detection of the expression of relevant genes at the protein and transcript levels, the results showed that dietary addition of creatine significantly alleviated intestinal apoptosis and cellular inflammatory responses due to DSS-induced enteritis. These findings indicate long-term dietary supplementation with creatine modulated the microbial composition of the intestinal lumen of juvenile largemouth bass, promoted intestinal health, and improved anti-inflammatory properties following enteritis induction. This study provides a theoretical foundation for largemouth bass feed formulation optimization and fish enteritis control.

Senescence-related circRNA circHIF-1α is associated with pancreatic cancer progression

Recently, there has been growing interest in the role of circular RNAs (circRNAs) in the progression of human cancers. Cellular senescence, a known anti-tumour mechanism, has been observed in several types of cancer. However, the regulatory interplay of circRNAs with cellular senescence in pancreatic cancer (PC) is still unknown. Therefore, we identified circHIF-1α, hsa_circ_0007976, which was downregulated in senescent cells using circRNA microarray analysis. Meanwhile, significantly upregulated expression of circHIF-1α in pancreatic cancer tissue detected by reverse transcription-polymerase chain reaction (RT-qPCR) and in situ hybridization (ISH). High circHIF-1α expression levels were found to independently predict poor survival outcomes. Subsequent treatments with DOX and H2O2 resulted in significantly lower levels of circHIF-1α. CircHIF-1α knockdown induces cellular senescence and suppresses PC proliferation in vitro experiments. The ability of circHIF-1α knockdown to suppress the progression of PC cells was further confirmed in vivo experiments. Our results showed that circHIF-1α is mainly presented in the nucleus of PC cells, also in the cytoplasm. Mechanistically, circHIF-1α inhibited senescence and accelerated the progression of PC cells through miR-375 sponging, thereby promoting HIF-1α expression levels. Nuclear circHIF-1α interacted with human antigen R protein (HUR) to increase HIF-1α expression. Thus, our results demonstrated that circHIF-1α ameliorates senescence and exacerbates growth in PC cells by increasing HIF-1α through targeting miR-375 and HUR, suggesting that targeting circHIF-1α offers a potential therapeutic candidate for PC.

TGFβ1 Restores Energy Homeostasis of Human Trophoblast Cells Under Hyperglycemia In Vitro by Inducing PPARγ Expression, AMPK Activation, and HIF1α Degradation.

Elevated glucose levels at the fetal-maternal interface are associated with placental trophoblast dysfunction and increased incidence of pregnancy complications. Trophoblast cells predominantly utilize glucose as an energy source, metabolizing it through glycolysis in the cytoplasm and oxidative respiration in the mitochondria to produce ATP. The TGFβ1/SMAD2 signaling pathway and the transcription factors PPARγ, HIF1α, and AMPK are key regulators of cell metabolism and are known to play critical roles in extravillous trophoblast cell differentiation and function. While HIF1α promotes glycolysis over mitochondrial respiration, PPARγ and AMPK encourage the opposite. However, the interplay between TGFβ1 and these energy-sensing regulators in trophoblast cell glucose metabolism remains unclear. This study aimed to investigate whether and how TGFβ1 regulates energy metabolism in trophoblast cells exposed to normal and high glucose conditions. The trophoblast JEG-3 cells were incubated in normal (5 mM) and high (25 mM) glucose conditions for 24 h in the absence and the presence of TGFβ1. The protein expression levels of phosphor (p)-SMAD2, GLUT1/3, HIF1α, PPARγ, p-AMPK, and specific OXPHOS protein subunits were determined by western blotting, and ATP and lactate production by bioluminescent assay kits. JEG-3 cells exposed to 25 mM glucose decreased ATP production but did not affect lactate production. These changes led to a reduction in the expression levels of GLUT1/3, mitochondrial respiratory chain proteins, and PPARγ, coinciding with an increase in HIF1α expression. Conversely, TGFβ1 treatment at 25 mM glucose reduced HIF1α expression while enhancing the expression levels of GLUT1/3, PPARγ, p-AMPK, and mitochondrial respiratory chain proteins, thereby rejuvenating ATP production. Our findings reveal that high glucose conditions disrupt cellular glucose metabolism in trophoblast cells by perturbing mitochondrial oxidative respiration and decreasing ATP production. Treatment with TGFβ1 appears to counteract this trend, probably by enhancing both glycolytic and mitochondrial metabolism, suggesting a potential regulatory role of TGFβ1 in placental trophoblast cell glucose metabolism.

Morphological and functional observations of a novel model of retinal ischemia injury induced by bilateral carotid artery stenosis in mice.

To investigate the features of retinal ischemic injuries in a novel mouse model with bilateral carotid artery stenosis (BCAS). BCAS was induced with microcoil implantation in 6-8-week-old C57BL6 mice. Cerebral blood flow was monitored at 2, 7, and 28d postoperatively. Retinal morphological changes were evaluated by fundus photography and hematoxylin-eosin staining. Fluorescein fundus angiography (FFA) was performed to detect retinal vascular changes and circulation. The levels of apoptosis, activation of neurogliosis, and expression of hypoxia-inducible factor (HIF)-1α in the retina were assessed by Western blotting and immunofluorescence staining, followed by retinal ganglion cell (RGC) density detection. Additionally, electrophysiological examinations including photopic negative response (PhNR) was also performed. The mice demonstrated an initial rapid decrease in cerebral blood flow, followed by a 4-week recovery period after BCAS. The ratio of retinal artery and vein was decreased under fundus photography and FFA. Compared with the sham mice, BCAS mice showed thinner retinal thickness on day 28. Additionally, apoptosis was increased and RGC density was decreased mainly in peripheral retinal region. Neurogliosis was mainly located in the inner retinal layers, with a stable increase in HIF-1α expression. The dark-adapted electroretinogram showed a notable reduction in the a-, b-, and oscillatory potential (OP) wave amplitudes between days 2 and 7; this gradually recovered over the following 4wk. However, the b- and OP-wave amplitudes were still significantly decreased on PhNR examination on day 28. BCAS can result in relatively mild retinal ischemia injuries in mice, mainly in the inner layer and peripheral region. Our study provides a novel animal model for investigating retinal ischemic diseases.

HIF-1Α IN SALIVA: A PROMISING BIOMARKER FOR EARLY DIAGNOSIS OF ORAL SUBMUCOUS FIBROSIS AND ITS MALIGNANT POTENTIAL

Oral submucous fibrosis (OSF) is a chronic condition with a high risk of transforming into oral squamous cell carcinoma (OSCC). Identifying reliable biomarkers for early diagnosis and monitoring of OSF is crucial for malignancy prevention. Objective: This study evaluates the expression of Hypoxia Inducible Factor-1α (HIF-1α) in saliva as a potential biomarker for OSF. Methods: Study was a cross-sectional study conducted in Karachi. The study was completed in 6 months from July 2023 to December 2023 and Sixty-five OSF patients participated in the study, providing saliva samples analyzed for HIF-1α expression using immunohistochemically (IHC). Clinic pathological features, including age, gender, body mass index (BMI), and etiological factors (tobacco, smoking, areca nut), were documented. Relationships between clinical symptoms (burning sensation, pain, ulceration, and dry mouth), fibrosis severity, and HIF-1α staining intensity in blood vessels and fibroblasts were assessed. Results: The study population included 68.3% males and 31.7% females, with a mean age of 32.56±4.12 years. Tobacco use (47.7%) was the most common etiology. HIF-1α expression was significantly elevated in fibroblasts compared to blood vessels, with mild staining in 54.2% of blood vessels and 49.8% of fibroblasts. Increased HIF-1α expression correlated with more severe OSF symptoms, indicating a higher risk of malignant transformation. Conclusion: HIF-1α is a promising biomarker for early diagnosis and assessment of malignant potential in OSF. Early detection and monitoring could improve clinical management and reduce OSCC risk, warranting further research for validation and therapeutic targeting.

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.

HIF-1α-HPRT1 axis promotes tumorigenesis and gefitinib resistance by enhancing purine metabolism in EGFR-mutant lung adenocarcinoma

BackgroundThe mutations of oncogenic epidermal growth factor receptor (EGFR) is an important cause of lung adenocarcinoma (LUAD) malignance. It has been knowm that metabolic reprogramming is an important hallmark of malignant tumors, and purine metabolism is a key metabolic pathway for tumor progression and drug resistance, but its relationship with the EGFR-mutant LUAD is unclear.MethodsMetabolic reprogramming was studied through capillary electrophoresis-time of flight mass spectrometry (CE-TOF/MS)-based metabolic profiling analysis. Cell proliferation in vitro was evaluated by EdU staining and cell cycle assay. Tumorigenicity in vivo was tested by subcutaneous tumor formation experiment in nude mice. The binding of hypoxia-inducible factor-1 alpha (HIF-1α) and hypoxanthine phosphoribosyltransferase 1 (HPRT1) was detected by DNA pull‑down assay and Chromatin immunoprecipitation (ChIP) assays. HIF-1α, HPRT1, DNA damage and cell apoptosis related genes were examined by western blot. In addition, RNA sequencing, mass spectrometry and bioinformatics analysis were performed.ResultsWe found that mutated EGFR (muEGFR) upregulates HPRT1 to promote purine metabolism and tumorigenesis of EGFR-mutant LUAD. Mechanistically, muEGFR increases HIF-1α expression through protein stability. Meanwhile, up-regulated HIF-1α bound to the promoter of HPRT1 and transcriptionally activates HPRT1 expression, enhancing purine metabolism to maintain rapid tumor cell proliferation in EGFR-mutant LUAD. Further, gefitinib inhibited the synthesis of purine nucleotides, and HPRT1 inhibition increased the sensitivity of gefitinib to EGFR-mutant LUAD.ConclusionsOur study reveals that muEGFR-HIF-1α-HPRT1 axis plays a key role in EGFR-mutant LUAD and provides a new strategy-inhibiting purine metabolism for treating EGFR-mutant LUAD.

Prognostic implications of HIF-1α expression in anal squamous cell carcinoma treated with intensity-modulated radiotherapy (IMRT)

BackgroundHypoxia-inducible factor-1α (HIF-1α) is a crucial transcription factor activated under hypoxic conditions, known to regulate genes associated with tumor survival, progression, and response to therapy. This study aimed to evaluate the prognostic significance of HIF-1α expression in patients with anal squamous cell carcinoma (ASCC) undergoing chemoradiation therapy. MethodsWe conducted a retrospective analysis of 28 ASCC patients treated with intensity-modulated radiotherapy (IMRT) at our center from 2009 to 2022. HIF-1α expression was assessed via immunohistochemistry on formalin-fixed paraffin-embedded tissue specimens. Quantitative analysis of HIF-1α expression was performed, and its relationship with clinical outcomes, including disease-free survival (DFS), locoregional relapse-free survival (LRRFS), and overall survival (OS), was examined using Cox regression models. Furthermore, ASCC tissue specimens from 17 patients were analyzed for potential PIK3CA mutations using Sanger sequencing. ResultsHigh HIF-1α expression was significantly associated with poorer DFS (p = 0.005), LRRFS (p = 0.012), and OS (p = 0.009). HIF1α expression was marginally significantly higher in males compared to females (p = 0.056) while there was no significant difference found based on tumor stage or p16 status. However, a positive correlation was identified between BMI and HIF-1α levels (Pearson correlation r = 0.5, p = 0.0084), suggesting a link between metabolic status and tumor hypoxia. Only one patient exhibited a PIK3CA mutation, preventing a reliable assessment of its correlation with HIF-1α expression. ConclusionOur findings underscore the importance of HIF-1α as a potential biomarker for predicting survival outcomes in ASCC patients treated with chemoradiation. The association between higher BMI and increased HIF-1α expression may provide insights into the interplay between metabolic health and tumor biology in ASCC. Further studies with larger cohorts are needed to validate these findings and explore targeted therapies focusing on HIF-1α modulation.

Bone Marrow Mesenchymal Stem Cell-Derived Exosomes Alleviate Nuclear Pulposus Cells Degeneration Through the miR-145a-5p/USP31/HIF-1α Signaling Pathway.

Bone marrow mesenchymal stem cell (BMSC)-derived exosomes possess therapeutic potential against degenerative diseases. This study aimed to investigate the effects of BMSC-derived exosomes on intervertebral disc degeneration (IVDD) and explore the underlying molecular mechanisms. Through transcriptome sequencing and histological analysis, we observed a significant increase in HIF-1α expression in degenerative nucleus pulposus (NP) tissues. The addition of HIF-1α resulted in elevated expression of inflammatory factors IL-1β and IL-6, higher levels of matrix-degrading enzyme MMP13, and lower expression of aggrecan in NP cells. Co-culturing with BMSCs diminished the expression of HIF-1α, MMP13, IL-1β, and IL-6 in degenerative NP cells induced by overload pressure. miRNA chip analysis and PCR validation revealed that miR-145a-5p was the primary miRNA carried by BMSC-derived exosomes. Overexpression of miR-145a-5p was effective in minimizing the expression of HIF-1α, MMP13, IL-1β, and IL-6 in degenerative NP cells. Luciferase reporter assays confirmed USP31 as the target gene of miR-145a-5p, and the regulation of NP cells by BMSC-derived exosomes via miR-145a-5p was dependent on USP31. In conclusion, BMSC-derived exosomes alleviated IVDD through the miR-145a-5p/USP31/HIF-1α signaling pathway, providing valuable insights into the treatment of IVDD.

Endothelin-1 increases Na+-K+-2Cl- cotransporter-1 expression in cultured astrocytes and in traumatic brain injury model: An involvement of HIF1α activation.

Na+-K+-2Cl- cotransporter-1 (NKCC1) is present in brain cells, including astrocytes. The expression of astrocytic NKCC1 increases in the acute phase of traumatic brain injury (TBI), which induces brain edema. Endothelin-1 (ET-1) is a factor that induces brain edema and regulates the expression of several pathology-related genes in astrocytes. In the present study, we investigated the effect of ET-1 on NKCC1 expression in astrocytes. ET-1 (100 nM)-treated cultured astrocytes showed increased NKCC1 mRNA and protein levels. The effect of ET-1 on NKCC1 expression in cultured astrocytes was reduced by BQ788 (1 μM), an ETB antagonist, but not by FR139317 (1 μM), an ETA antagonist. The involvement of ET-1 in NKCC1 expression in TBI was examined using a fluid percussion injury (FPI) mouse model that replicates the pathology of TBI with high reproducibility. Administration of BQ788 (15 nmol/day) decreased FPI-induced expressions of NKCC1 mRNA and protein, accompanied with a reduction of astrocytic activation. FPI-induced brain edema was attenuated by BQ788 and NKCC1 inhibitors (azosemide and bumetanide). ET-1-treated cultured astrocytes showed increased mRNA and protein expression of hypoxia-inducible factor-1α (HIF1α). Immunohistochemical observations of mouse cerebrum after FPI showed co-localization of HIF1α with GFAP-positive astrocytes. Increased HIF1α expression in the TBI model was reversed by BQ788. FM19G11 (an HIF inhibitor, 1 μM) and HIF1α siRNA suppressed ET-induced increase in NKCC1 expression in cultured astrocytes. These results indicate that ET-1 increases NKCC1 expression in astrocytes through the activation of HIF1α.

Differential but complementary roles of HIF-1α and HIF-2α in the regulation of bone homeostasis

Bone is a highly dynamic tissue undergoing continuous formation and resorption. Here, we investigated differential but complementary roles of hypoxia-inducible factor (HIF)-1α and HIF-2α in regulating bone remodeling. Using RNA-seq analysis, we identified that specific genes involved in regulating osteoblast differentiation were similarly but slightly differently governed by HIF-1α and HIF-2α. We found that increased HIF-1α expression inhibited osteoblast differentiation via inhibiting RUNX2 function by upregulation of Twist2, confirmed using Hif1a conditional knockout (KO) mouse. Ectopic expression of HIF-1α via adenovirus transduction resulted in the increased expression and activity of RANKL, while knockdown of Hif1a expression via siRNA or osteoblast-specific depletion of Hif1a in conditional KO mice had no discernible effect on osteoblast-mediated osteoclast activation. The unexpected outcome was elucidated by the upregulation of HIF-2α upon Hif1a overexpression, providing evidence that Hif2a is a transcriptional target of HIF-1α in regulating RANKL expression, verified through an experiment of HIF-2α knockdown after HIF-1α overexpression. The above results were validated in an ovariectomized- and aging-induced osteoporosis model using Hif1a conditional KO mice. Our findings conclude that HIF-1α plays an important role in regulating bone homeostasis by controlling osteoblast differentiation, and in influencing osteoclast formation through the regulation of RANKL secretion via HIF-2α modulation.

L-2-Hydroxyglutarate contributes to tumor radioresistance through regulating the hypoxia-inducible factor-1α signaling pathway.

l-2-Hydroxyglutarate (l-2-HG) has been regarded as a tumor metabolite, and it plays a crucial role in adaptation of tumor cells to hypoxic conditions. However, the role of l-2-HG in tumor radioresistance and the underlying mechanism have not yet been revealed. Here, we found that l-2-HG exhibited to have radioresistance effect on U87 human glioblastoma cells, which could reduce DNA damage and apoptosis caused by irradiation, promote cell proliferation and migration, and impair G2/M phase arrest. Mechanistically, l-2-HG upregulated the protein level of hypoxia-inducible factor-1α (HIF-1α) and the expression levels of HIF-1α downstream target genes. The knockdown ofl-2-hydroxyglutarate dehydrogenase(L2HGDH) gene promoted the tumor growth and proliferation of U87 cells in nude mice by increasing HIF-1α expression level in vivo. In addition, the low expression level of L2HGDH gene was correlated with the short survival of patients with glioma or kidney cancer. In conclusion, our study revealed the role and mechanism of l-2-HG in tumor radioresistance and may provide a new perspective for overcoming tumor radioresistance and broaden our comprehension of the role of metabolites in tumor microenvironment.

Dimethyloxalylglycine (DMOG) Induced Hypoxia Promoted Migratory and Invasive Properties of HCT116 Colon Cancer Cell Line

Hypoxia, a condition characterised by low oxygen levels, leads to increased production of a protein called hypoxia-inducible factor-1 alpha (HIF-1α) in cancer cells. This protein is involved in driving processes such as vascularization, cytoskeletal reorganisation, and epithelial-to-mesenchymal transformation (EMT), which contribute to metastasis. Previous studies used hypoxic workstations, chambers, and incubators to evaluate the effects of hypoxia on colon cancer cell lines. In a cell culture model, hypoxic conditions can also be induced using dimethyloxalylglycine (DMOG) as the hypoxia-mimicking agent. This study aims to investigate the effects of DMOG-induced hypoxia on colon cancer metastasis, focusing on cell migration and invasion. HCT116 cells were subjected to hypoxic conditions by treating them with DMOG, and the expression of HIF-1α proteins was measured at various time points, followed by wound healing and invasion assays. It was found that HIF-1α protein expression increases after 6 h of DMOG induction and persists for 24 h. At 6 and 24 h, a significantly higher percentage of hypoxic cells migrated compared to normoxic cells. The invasion assay demonstrated that hypoxic cells were more invasive than normoxic cells within 24 h. Thus, the increase in migration and invasion of cells is comparable to the increase in HIF-1α expression at 6 and 24 h. These findings suggest that DMOG induces HIF-1α expression in colon cancer cells, leading to enhanced cell migration and invasiveness. The established model can be further utilised in gene knockdown or drug treatment studies to evaluate the effects of hypoxia on cancer cells.

Fructose vs. glucose: modulating stem cell growth and function through sugar supplementation.

In multicellular organisms, stem cells are impacted by microenvironmental resources such as nutrient availability and oxygen tension for their survival, growth, and differentiation. However, the accessibility of these resources in the pericellular environment greatly varies from organ to organ. This divergence in resource availability leads to variations in the potency and differentiation potential of stem cells. This study aimed to explore the distinct effects of glucose and fructose, as well as different oxygen tensions, on the growth dynamics, cytokine production, and differentiation of stem cells. We showed that replacing glucose with fructose subjected stem cells to stress, resulting in increased Hif1α expression and stability, which in turn led to a reduction in cell proliferation, and alterations in cytokine production. However, fructose failed to induce differentiation of human mesenchymal stem cells (hMSCs) as well as mouse fibroblasts into mature adipocytes compared to glucose, despite the upregulation of key markers of adipogenesis, including C/EBPβ, and PPARγ. Conversely, we showed that fructose induced undifferentiated mouse fibroblasts to release cytokines associated with senescence, including IL1α1, IL6, IL8, MCP1, and TNF1α, suggesting that these cells were undergoing lipolysis. Taken together, our results suggest that altering the culture conditions through changes in hexose levels and oxygen tension places considerable stress on stem cells. Additional research is required to further characterize the mechanisms governing stem cell response to their microenvironments.

Deoxynivalenol induces cell senescence in RAW264.7 macrophages via HIF-1α-mediated activation of the p53/p21 pathway

Deoxynivalenol (DON), a potent mycotoxin, exhibits strong immunotoxicity and poses a significant threat to human and animal health. Cell senescence has been implicated in the immunomodulatory effects of DON; however, the potential of DON to induce cell senescence remains inadequately explored. Emerging evidence suggests that hypoxia-inducible factor-1α (HIF-1α) serves as a crucial target of mycotoxins and is closely involved in cell senescence. To investigate this potential, we employed the RAW264.7 macrophage model and treated the cells with varying concentrations of DON (2–8 μM) for 24 h. Transcriptome analysis revealed that 2365 genes were significantly upregulation while 2405 genes were significantly decreased after exposure to DON. KEGG pathway enrichment analysis demonstrated substantial enrichment in pathways associated with cellular senescence and hypoxia. Remarkably, we observed a rapid and sustained increase in HIF-1α expression following DON treatment. DON induced cell senescence through the activation of the p53/p21WAF1/CIP1 (p21) and p16INK4A (p16) pathways, while also upregulating the expression of nuclear factor-κB, leading to the secretion of senescence-associated secretory phenotype (SASP) factors, including IL-6, IL-8, and CCL2. Crucially, HIF-1α positively regulated the expression of p53, p21, and p16, as well as the secretion of SASP factors. Additionally, DON induced cell cycle arrest at the S phase, enhanced the activity of the senescence biomarker senescence-associated β-galactosidase, and disrupted cell morphology, characterized by mitochondrial damage. Our study elucidates that DON induces cell senescence in RAW264.7 macrophages by modulating the HIF-1α/p53/p21 pathway. These findings provide valuable insights for the accurate prevention of DON-induced immunotoxicity and associated diseases.

SPA inhibits hBMSC osteogenic differentiation and M1 macrophage polarization by suppressing SETD2 in acute suppurative osteomyelitis

To clarify the impact of SETD2 on macrophage function in pediatric patients with acute suppurative osteomyelitis and to elucidate the precise underlying mechanism. To gain insights into the potential functions of SETD2, a comprehensive study was conducted utilizing a co-culture model of human bone mesenchymal stem cells (hBMSCs) and bone marrow-derived macrophages (THP-1). A range of techniques were employed, including quantitative polymerase chain reaction, western blotting, ELISA, alkaline phosphatase activity assays, alizarin red S staining, luciferase reporter gene assays, and chromatin immunoprecipitation, to unravel the intricate interactions and molecular mechanisms involving SETD2 in this system. It was observed that SETD2 expression was reduced in THP-1 cells stimulated by staphylococcal protein A (SPA). Furthermore, the downregulation of SETD2 resulted in elevated M1 macrophage polarization and glycolysis, effects that were mitigated by SPA stimulation. Notably, SPA-stimulated THP-1 cells exhibited an increase in HIF-1α expression, which exhibited an inverse correlation with SETD2 levels. Moreover, it was discovered that SETD2 functioned as a catalyst for H3K36me3 and bound to the HIF-1α gene, which, in turn, regulated HIF-1α expression. Furthermore, the suppression of HIF-1α abrogated the consequences of SETD2 downregulation on glycolysis and M1 macrophage polarization. Lastly, the study demonstrated that M1 macrophage polarization serves as a mediator for BMP4’s inhibitory effect on osteogenic differentiation of hBMSCs. This research has uncovered a previously unknown role of SETD2 in macrophages during osteomyelitis, revealing its significance in the pathogenesis of this condition. These findings suggest SETD2 as a novel target for the treatment of osteomyelitis.

Modulation of the HIF-1α-NCOA4-FTH1 Signaling Axis Regulating Ferroptosis-induced Hepatic Stellate Cell Senescence to Explore the Anti-hepatic Fibrosis Mechanism of Curcumol.

Senescence of activated hepatic stellate cells (HSC) reduces extracellular matrix expression to reverse liver fibrosis. Ferroptosis is closely related to cellular senescence, but its regulatory mechanisms need to be further investigated. The iron ions weakly bound to ferritin in the cell are called labile iron pool (LIP), and together with ferritin, they maintain cellular iron homeostasis and regulate the cell's sensitivity to ferroptosis. We used lipopolysaccharide (LPS) to construct a pathological model group and divided the hepatic stellate cells into a blank group, a model group, and a curcumol 12.5 mg/L group, a curcumol 25 mg/L group, and a curcumol 50 mg/L group. HIF-1α-NCOA4- FTH1 signalling axis, ferroptosis and cellular senescence were detected by various cellular molecular biology experiments. We found that curcumol could induce hepatic stellate cell senescence by promoting iron death in hepatic stellate cells. Curcumol induced massive deposition of iron ions in hepatic stellate cells by activating the HIF-1α-NCOA4-FTH1 signalling axis, which further led to iron overload and lipid peroxidation-induced ferroptosis. Interestingly, our knockdown of HIF-1α rescued curcumol-induced LIP and iron deposition in hepatic stellate cells, suggesting that HIF-1α is a key target of curcumol in regulating iron metabolism and ferroptosis. We were able to rescue curcumol-induced hepatic stellate cell senescence when we reduced LIP and iron ion deposition using iron chelators. Overall, curcumol induces ferroptosis and cellular senescence by increasing HIF-1α expression and increasing NCOA4 interaction with FTH1, leading to massive deposition of LIP and iron ions, which may be the molecular biological mechanism of its anti-liver fibrosis.

UCHL1-dependent control of hypoxia-inducible factor transcriptional activity during liver fibrosis.

Liver fibrosis is the excessive accumulation of extracellular matrix proteins that occurs in most types of chronic liver disease. At the cellular level, liver fibrosis is associated with the activation of hepatic stellate cells (HSCs) which transdifferentiate into a myofibroblast-like phenotype that is contractile, proliferative and profibrogenic. HSC transdifferentiation induces genome-wide changes in gene expression that enable the cell to adopt its profibrogenic functions. We have previously identified that the deubiquitinase ubiquitin C-terminal hydrolase 1 (UCHL1) is highly induced following HSC activation; however, the cellular targets of its deubiquitinating activity are poorly defined. Here, we describe a role for UCHL1 in regulating the levels and activity of hypoxia-inducible factor 1 (HIF1), an oxygen-sensitive transcription factor, during HSC activation and liver fibrosis. HIF1 is elevated during HSC activation and promotes the expression of profibrotic mediator HIF target genes. Increased HIF1α expression correlated with induction of UCHL1 mRNA and protein with HSC activation. Genetic deletion or chemical inhibition of UCHL1 impaired HIF activity through reduction of HIF1α levels. Furthermore, our mechanistic studies have shown that UCHL1 elevates HIF activity through specific cleavage of degradative ubiquitin chains, elevates levels of pro-fibrotic gene expression and increases proliferation rates. As we also show that UCHL1 inhibition blunts fibrogenesis in a pre-clinical 3D human liver slice model of fibrosis, these results demonstrate how small molecule inhibitors of DUBs can exert therapeutic effects through modulation of HIF transcription factors in liver disease. Furthermore, inhibition of HIF activity using UCHL1 inhibitors may represent a therapeutic opportunity with other HIF-related pathologies.

GSK-3α-BNIP3 axis promotes mitophagy in human cardiomyocytes under hypoxia

Dysregulated autophagy/mitophagy is one of the major causes of cardiac injury in ischemic conditions. Glycogen synthase kinase-3alpha (GSK-3α) has been shown to play a crucial role in the pathophysiology of cardiac diseases. However, the precise role of GSK-3α in cardiac mitophagy remains unknown. Herein, we investigated the role of GSK-3α in cardiac mitophagy by employing AC16 human cardiomyocytes under the condition of acute hypoxia. We observed that the gain-of-GSK-3α function profoundly induced mitophagy in the AC16 cardiomyocytes post-hypoxia. Moreover, GSK-3α overexpression led to increased ROS generation and mitochondrial dysfunction in cardiomyocytes, accompanied by enhanced mitophagy displayed by increased mt-mKeima intensity under hypoxia. Mechanistically, we identified that GSK-3α promotes mitophagy through upregulation of BNIP3, caused by GSK-3α-mediated increase in expression of HIF-1α and FOXO3a in cardiomyocytes post-hypoxia. Moreover, GSK-3α displayed a physical interaction with BNIP3 and, inhibited PINK1 and Parkin recruitment to mitochondria was observed specifically under hypoxia. Taken together, we identified a novel mechanism of mitophagy in human cardiomyocytes. GSK-3α promotes mitochondrial dysfunction and regulates FOXO3a -mediated BNIP3 overexpression in cardiomyocytes to facilitate mitophagy following hypoxia. An interaction between GSK-3α and BNIP3 suggests a role of GSK-3α in BNIP3 recruitment to the mitochondrial membrane where it enhances mitophagy in stressed cardiomyocytes independent of the PINK1/Parkin.

Exposure to fine particulate matter 2.5 from wood combustion smoke causes vascular changes in placenta and reduce fetal size

During gestation, maternal blood flow to the umbilical cord and placenta increases, facilitating efficient nutrient absorption, waste elimination, and effective gas exchange for the developing fetus. However, the effects of exposure to wood smoke during this period on these processes are unknown. We hypothesize that exposure to PM2.5, primarily sourced from wood combustion for home heating, affects placental vascular morphophysiology and fetal size. We used exposure chambers that received either filtered or unfiltered air. Female rats were exposed to PM2.5 during pre-gestational and/or gestational stages. Twenty-one days post-fertilization, placentas were collected via cesarean section. In these placentas, oxygen diffusion capacity was measured, and the expression of angiogenic factors was analyzed using qPCR and immunohistochemistry. In groups exposed to PM2.5 during pre-gestational and/or gestational stages, a decrease in fetal weight, crown-rump length, theoretical and specific diffusion capacity, and an increase in HIF-1α expression were observed. In groups exposed exclusively to PM2.5 during the pre-gestational stage, there was an increase in the expression of placental genes Flt-1, Kdr, and PIGF. Additionally, in the placental labyrinth region, the expression of angiogenic factors was elevated. Changes in angiogenesis and angiogenic factors reflect adaptations to hypoxia, impacting fetal growth and oxygen supply. In conclusion, this study demonstrates that exposure to PM2.5, emitted from wood smoke, in both pre-gestational and gestational stages, affects fetal development and placental health. This underscores the importance of addressing air pollution in areas with high levels of wood smoke, which poses a significant health risk to pregnant women and their fetuses.