HIF-1α Protein Levels Research Articles

The long non-coding RNA mir155hg promotes NLRP3-inflammasome activation and oxidative stress response in acute lung injury by targeting miR-450b-5p to regulate HIF-1α

BackgroundAcute lung injury (ALI) can cause multiple organ dysfunction and a high mortality rate. Inflammatory responses, oxidative stress, and immune damage contribute to their pathogenic mechanisms. We studied the role of the newly discovered lncRNA, Lncmir155hg, in ALI. MethodsThe levels of Lncmir155hg and miR-450b-5p from mice with ALI were detected via polymerase chain reaction analysis (qRT-PCR) and Fluorescence in situ hybridization (FISH). Pathological changes of lung were detected by HE (hematoxylin and eosin) staining, and HIF-1α, NOD-like receptor 3 (NLRP3) and caspase-1 protein changes were detected by immunohistochemistry. MLE-12 cells proliferation was detected by Cell-Counting Kit 8 analysis, and reactive oxygen species (ROS) was detected via flow cytometry. NLRP3, apoptosis-associated speck-like protein (ASC), and caspase-1 were measured via western blotting, and enzyme-linked immunosorbent assays detected the expression of Inflammatory factors. Lncmir155hg, miR-450b-5p, miR-450b-5p, and HIF-1α targets were predicted using LncTar and miRWalk and confirmed in dual-luciferase reporter assays. ResultsIn mice with ALI and MLE-12 cells induced by lipopolysaccharide (LPS), Lncmir155hg was high-expressed and miR-450b-5p was low-expressed. sh-Lncmir155hg reduced the damage of lung tissue, the production of inflammatory cytokines and oxidative stress reaction induced by LPS，miR-450b-5p reverses the effect of Lncmir155hg in mice. sh-Lncmir155hg decreased the protein levels of HIF-1α, NLRP3 and caspase-1 in LPS-induced lung tissues. sh-Lncmir155hg + miR-450b-5p inhibitor transfection reversed the effect of sh-Lncmir155hg on the expression of HIF-1α, NLRP3 and caspase-1. Lncmir155hg knockdown induced proliferation and inhibited NLRP3-inflammasome activation and oxidative stress in MLE-12 cells of ALI. miR-450b-5p was identified to have binding with Lncmir155hg, and inhibition of miR-450b-5p eliminated the effect of si-Lncmir155hg in MLE-12 cells of ALI. More importantly, miR-450b-5p was directly combined with HIF-1α, miR-450b-5p mimic promoted proliferation and inhibited activation of inflammasome associated proteins and reaction of oxidative stress, and HIF-1α overexpression abolished these effects. ConclusionLncmir155hg aggravated ALI via the miR-450b-5p/HIF-1α axis.

Cannabidiol effectively prevents oxidative stress and stabilizes hypoxia-inducible factor-1 alpha (HIF-1α) in an animal model of global hypoxia

Cannabidiol (CBD) is a non-psychotomimetic phytocannabinoid derived from Cannabis sativa. It has therapeutic effects in different paradigms of brain injury, acting as a neuroprotectant. As oxidative stress is a primary risk factor for brain damage after neonatal hypoxia, we tested the effect of CBD on oxidative status and non-protein-bound iron accumulation in the immature brain after hypoxia. Moreover, we tested whether cannabidiol affects the accumulation of hypoxia-inducible factor-1 alpha (HIF-1α) which plays a key role in the regulation of cellular adaptation to hypoxia and oxidative stress. We used 7-day-old mice randomly assigned to hypoxic or control groups. Immediately after hypoxia or control exposure, pups were randomly assigned to a vehicle or CBD treatment. 24 h later, they were decapitated and the brains were immediately removed and stored for further biochemical analyses. We found that CBD reduced lipid peroxidation and prevented antioxidant depletion. For the first time, we also demonstrated that CBD upregulated HIF-1α protein level. This study indicates that CBD may effective agent in attenuating the detrimental consequences of perinatal asphyxia.

N-Phenyl-2-Pyridone-Derived Endoperoxide Suppressing both Lung Cancer and Idiopathic Pulmonary Fibrosis Progression by Three-Pronged Action.

We report an endoperoxide compound (E5) which can deliver three therapeutic components by a thermal cycloreversion, namely, singlet oxygen, triplet oxygen and 3-methyl-N-phenyl-2-pyridone (P5), thus targeting multiple mechanisms for treating non-small cell lung cancer and idiopathic pulmonary fibrosis. In aqueous environment, E5 undergoes clean reaction to afford three therapeutic components with a half-life of 8.3 hours without the generation of other by-products, which not only achieves good cytotoxicity toward lung cancer cells and decreases the levels of hypoxia-inducible factor 1α (HIF-1α) protein, but also inhibits the transforming growth factor β1 (TGF-β1) induced fibrosis in vitro. In vivo experiments also demonstrated the efficacy of E5 in inhibiting tumor growth and relieving idiopathic pulmonary fibrosis, while exhibiting good biocompatibility. Many lines of evidence reveal the therapeutic efficacy of singlet oxygen and 3-methyl-N-phenyl-2-pyridone for these two lung diseases, and triplet oxygen could downregulate HIF-1α and relieve tumor hypoxia which is a critical issue in photodynamic therapy (PDT). Unlike other combination therapies, in which multiple therapeutic agents are given in independent formulations, our work demonstrates single molecule endoperoxide prodrugs could be developed as new platforms for treatment of cancers and related diseases.

B7-H3 enhances colorectal cancer progression by regulating HB-EGF via HIF-1α.

B7-H3 (or CD276) represents an important costimulatory molecule expressed in many malignant solid tumors, including colorectal cancer (CRC). The receptor of B7-H3 is not known, and the intracellular function of B7-H3 remains obscure. Herein, we report that B7-H3 upregulated the epidermal growth factor heparin-binding epidermal growth factor (HB-EGF), likely by regulating hypoxia-inducible factor 1α (HIF-1α) and thereby promoting the progression of CRC. Lentiviral transfection was performed on CRC cells to establish stable low-B7-H3 expression cells. A mechanistic analysis with an Agilent human gene expression profiling chip was conducted on them. Clinical data and specimens were collected to detect the connection between B7-H3 and HB-EGF in CRC. Quantitative real-time polymerase chain reaction (qRT-PCR) was conducted to detect the messenger RNA (mRNA) level of B7-H3, HB-EGF, and HIF-1α. Chromatin immunoprecipitation (ChIP) quantitative real-time PCR was conducted. The protein level of HIF-1α and the phosphatidylinositide 3-kinases (PI3K)-protein kinase B (AKT) pathway were detected by western blot. HIF-1α was recovered by lentiviral transfection, and the HB-EGF mRNA levels, proliferation, invasion, and angiogenesis ability were detected. B7-H3 promoted tumor progression through HB-EGF and the PI3K-AKT pathway. As B7-H3 was downregulated, HB-EGF levels were significantly reduced simultaneously, a growth trend that was shown by both CRC cell lines and cancer tissues. In addition, B7-H3 and HB-EGF had significant associations with tumor-node-metastasis (TNM) stage and lymph node metastasis in 50 CRC patients. The binding ability of HIF-1α to the HB-EGF promoter region was significantly decreased in the shB7-H3 RKO group. Western blot revealed that PI3K, AKT, and mammalian target of rapamycin (mTOR) protein amounts and p-AKT and p-mTOR phosphorylation were also downregulated in shB7-H3 RKO cells, suggesting that B7-H3 may regulate HIF-1α via PI3K-AKT signaling. After recovery of the HIF-1α level by lentiviral transfection, the HB-EGF mRNA levels, proliferation, invasion, and angiogenesis in CRC cells recovered as well. B7-H3 may transmit intracellular signals through PI3K-AKT-mTOR-HIF-1α signaling, upregulating HB-EGF. As the final transcription factor of the pathway, HIF-1α regulates the transcription of the HB-EGF gene, thereby promoting HB-EGF expression, which eventually mediates cell proliferation, invasion, and angiogenesis and promotes the progression of CRC.

UBE2S promotes glycolysis in hepatocellular carcinoma by enhancing E3 enzyme-independent polyubiquitination of VHL.

Ubiquitination is widely involved in the progression of hepatocellular carcinoma (HCC) by regulating various cellular processes. However, systematic strategies for screening core ubiquitin-related genes, clarifying their functions and mechanisms, and ultimately developing potential therapeutics for patients with HCC are still lacking. Cox and LASSO regression analyses were performed to construct a ubiquitin-related gene prediction model for HCC. Loss- and gain-of-function studies, transcriptomic and metabolomics analysis were used to explore the function and mechanism of UBE2S on HCC cell glycolysis and growth. Based on 1,423 ubiquitin-related genes, a four-gene signature was successfully constructed to evaluate the prognosis of patients with HCC. UBE2S was identified in this signature with the potential to predict the survival of patients with HCC. E2F2 transcriptionally upregulated UBE2S expression by directly binding to its promoter. UBE2S positively regulated glycolysis in a HIF-1α-dependent manner, thus promoting the proliferation of HCC cells. Mechanistically, UBE2S enhanced K11-linkage polyubiquitination at lysine residues 171 and 196 of VHL independent of E3 ligase, thereby indirectly stabilizing HIF-1α protein levels by mediating the degradation of VHL by the proteasome. In particular, the combination of cephalomannine, a small molecule compound that inhibits the expression of UBE2S, and PX-478, an inhibitor of HIF-1α, significantly improved the anti-tumor efficacy. UBE2S is identified as a key biomarker in HCC among the thousands of ubiquitin-related genes and promotes glycolysis by E3 enzyme-independent ubiquitination, thus serving as a therapeutic target for the treatment of HCC.

HIF-2α expression and metabolic signaling require ACSS2 in clear cell renal cell carcinoma.

Clear cell renal cell carcinoma (ccRCC) is an aggressive cancer driven by VHL loss and aberrant HIF-2α signaling. Identifying means to regulate HIF-2α thus has potential therapeutic benefit. Acetyl-CoA synthetase 2 (ACSS2) converts acetate to acetyl-CoA and is associated with poor patient prognosis in ccRCC. Here we tested the effects of ACSS2 on HIF-2α and cancer cell metabolism and growth in ccRCC models and clinical samples. ACSS2 inhibition reduced HIF-2α levels and suppressed ccRCC cell line growth in vitro, in vivo, and in cultures of primary ccRCC patient tumors. This treatment reduced glycolytic signaling, cholesterol metabolism, and mitochondrial integrity, all of which are consistent with loss of HIF-2α. Mechanistically, ACSS2 inhibition decreased chromatin accessibility and HIF-2α expression and stability. While HIF-2α protein levels are widely regulated through pVHL-dependent proteolytic degradation, we identify a potential pVHL-independent pathway of degradation via the E3 ligase MUL1. We show that MUL1 can directly interact with HIF-2α and that overexpression of MUL1 decreased HIF-2α levels in a manner partially dependent on ACSS2. These findings identify multiple mechanisms to regulate HIF-2α stability and ACSS2 inhibition as a strategy to complement HIF-2α-targeted therapies and deplete pathogenically stabilized HIF-2α.

HIF1A protein expression is correlated with clinical features in gastric cancer: an updated systematic review and meta-analysis

To elucidate the correlation of HIF1A with clinicopathologic characteristics in patients with gastric cancer (GC), we conducted a systematic review and meta-analysis. We searched PubMed, Embase and Web of Science for studies on GC and HIF1A, covering studies published until January 31st, 2022. We calculated odds ratios (ORs) and 95% confidence intervals (CIs) for clinical characteristics based on high and low HIF1A protein levels. We used random-effects and fixed-effects meta-analysis methods to determine mean effect sizes of ORs and evaluated publication heterogeneity with τ2, I2, and Q values. Additionally, we generated funnel plots to inspect publication bias. Our meta-analysis included 20 publications with 3416 GC patients to estimate the association between high or low HIF1A expression and clinical characteristics. Positive HIF1A expression was significantly associated with T stage progression (OR: 2.46; 95% CI 1.81–3.36; P < 0.01), TNM stage progression (OR: 2.50; 95% CI 1.61–3.87; P < 0.01), lymph node metastasis (OR: 2.06; 95% CI 1.44–2.94; P < 0.01), undifferentiated status (OR: 1.83; 95% CI 1.45–2.32; P < 0.01), M stage progression (OR: 2.34; 95% CI 1.46–3.77; P < 0.01), Borrmann stage progression (OR: 1.48; 95% CI 1.02–2.15; P = 0.04), larger tumor size (OR: 1.27; 95% CI 1.06–1.52; P < 0.01), vascular invasion (OR: 1.94; 95% CI 1.38–2.72; P < 0.01), and higher vascular endothelial growth factor (VEGF) protein expression (OR: 2.61; 95% CI 1.79–3.80; P < 0.01) in our meta-analysis. GC Patients highly expressing HIF1A protein might be prone to tumor progression, poorly differentiated GC cell types, and a high VEGF expression.

REST-dependent downregulation of von Hippel-Lindau tumor suppressor promotes autophagy in SHH-medulloblastoma

The RE1 silencing transcription factor (REST) is a driver of sonic hedgehog (SHH) medulloblastoma genesis. Our previous studies showed that REST enhances cell proliferation, metastasis and vascular growth and blocks neuronal differentiation to drive progression of SHH medulloblastoma tumors. Here, we demonstrate that REST promotes autophagy, a pathway that is found to be significantly enriched in human medulloblastoma tumors relative to normal cerebella. In SHH medulloblastoma tumor xenografts, REST elevation is strongly correlated with increased expression of the hypoxia-inducible factor 1-alpha (HIF1α)—a positive regulator of autophagy, and with reduced expression of the von Hippel-Lindau (VHL) tumor suppressor protein – a component of an E3 ligase complex that ubiquitinates HIF1α. Human SHH-medulloblastoma tumors with higher REST expression exhibit nuclear localization of HIF1α, in contrast to its cytoplasmic localization in low-REST tumors. In vitro, REST knockdown promotes an increase in VHL levels and a decrease in cytoplasmic HIF1α protein levels, and autophagy flux. In contrast, REST elevation causes a decline in VHL levels, as well as its interaction with HIF1α, resulting in a reduction in HIF1α ubiquitination and an increase in autophagy flux. These data suggest that REST elevation promotes autophagy in SHH medulloblastoma cells by modulating HIF1α ubiquitination and stability in a VHL-dependent manner. Thus, our study is one of the first to connect VHL to REST-dependent control of autophagy in a subset of medulloblastomas.

The Expression of Hypoxia-Inducible Factor-1 Alpha (HIF-1α) as a Potential Target for Hypoxic Therapy in COVID-19 Cases

Background: The cellular response to hypoxia is characterized by the stabilization of the HIF-1α protein, which will form a transcription factor that activates genes for low oxygen adaptation. Positive cases of COVID-19 are often characterized by hypoxia, especially in patients with comorbidities. This hypoxic condition will mediate drug resistance or weaken the patient's condition, resulting in lengthening treatment time and even causing death. This study aims to analyze the cellular expression of the HIF-1α gene in patients confirmed positive for COVID-19 with the alpha, beta, delta, and omicron variants. Methods: The research design used was observational, with parameters measuring HIF-1 mRNA expression (RT-PCR, protein (ELISA), and its correlation. The samples used were nose-throat swabs from COVID-19 patients. Results: The expression of HIF-1α mRNA and protein levels produced in variants of COVID-19 patients was compared with controls (times; ng/mL): alpha (0.53; 18.08), beta (0.92; 19.98), delta (0.65; 25.83), and omicron (0.73; 19.85) (Kruskal-Wallis test, p &lt;0.01). The correlation between mRNA expression of HIF-1α and HIF-1α proteins was found to be significantly negative (Pearson Correlation test R = -0.589). Conclusion: In this study, it was found that a decrease in HIF-1α mRNA expression (the result of transcription) increased the levels of HIF-1α protein (the result of translation) and stable HIF-1α expression. Moreover, cellular hypoxia occurred in patients with confirmed positive for COVID-19, with the alpha, beta, delta, and omicron variants. This study can be used as a basis for therapy to control viruses that cause hypoxia in the future. result: The expression of HIF-1α mRNA and protein levels produced in variants of COVID-19 patients compared with controls (times; ng/mL): alpha (0.53; 18.08), beta (0.92; 19.98), delta (0.65 ; 25.83), omicron (0.73; 19.85) (Kruskal Wallis test, p &lt;0.01); The correlation between mRNA expression of HIF-1α and HIF-1α proteins obtained strong negative results (Pearson Correlation test R = -0.589 ).

Role of hypoxia-mediated pyroptosis in the development of extending knee joint contracture in rats

Joint contracture is one of the common diseases clinically, and joint capsule fibrosis is considered to be one of the most important pathological changes of joint contracture. However, the underlying mechanism of joint capsule fibrosis is still controversial. The present study aims to establish an animal model of knee extending joint contracture in rats, and to investigate the role of hypoxia-mediated pyroptosis in the progression of joint contracture using this animal model. 36 male SD rats were selected, 6 of which were not immobilized and were used as control group, while 30 rats were divided into I-1 group (immobilized for 1 week following 7 weeks of free movement), I-2 group (immobilized for 2 weeks following 6 weeks of free movement), I-4 group (immobilized for 4 weeks following 4 weeks of free movement), I-6 group (immobilized for 6 weeks following 2 weeks of free movement) and I-8 group (immobilized for 8 weeks) according to different immobilizing time. The progression of joint contracture was assessed by the measurement of knee joint range of motion, collagen deposition in joint capsule was examined with Masson staining, protein expression levels of HIF-1α, NLRP3, Caspase-1, GSDMD-N, TGF-β1, α-SMA and p-Smad3 in joint capsule were assessed using western blotting, and the morphological changes of fibroblasts were observed by transmission electron microscopy. The degree of total and arthrogenic contracture progressed from the first week and lasted until the first eight weeks after immobilization. The degree of total and arthrogenic contracture progressed rapidly in the first four weeks after immobilization and then progressed slowly. Masson staining indicated that collagen deposition in joint capsule gradually increased in the first 8 weeks following immobilization. Western blotting analysis showed that the protein levels of HIF-1α continued to increase during the first 8 weeks of immobilization, and the protein levels of pyroptosis-related proteins NLRP3, Caspase-1, GSDMD-N continued to increase in the first 4 weeks after immobilization and then decreased. The protein levels of fibrosis-related proteins TGF-β1, p-Smad3 and α-SMA continued to increase in the first 8 weeks after immobilization. Transmission electron microscopy showed that 4 weeks of immobilization induced cell membrane rupture and cell contents overflow, which further indicated the activation of pyroptosis. Knee extending joint contracture animal model can be established by external immobilization orthosis in rats, and the activation of hypoxia-mediated pyroptosis may play a stimulating role in the process of joint capsule fibrosis and joint contracture.

METTL8 links mt-tRNA m3C modification to the HIF1α/RTK/Akt axis to sustain GBM stemness and tumorigenicity

Epitranscriptomic RNA modifications are crucial for the maintenance of glioma stem cells (GSCs), the most malignant cells in glioblastoma (GBM). 3-methylcytosine (m3C) is a new epitranscriptomic mark on RNAs and METTL8 represents an m3C writer that is dysregulated in cancer. Although METTL8 has an established function in mitochondrial tRNA (mt-tRNA) m3C modification, alternative splicing of METTL8 can also generate isoforms that localize to the nucleolus where they may regulate R-loop formation. The molecular basis for METTL8 dysregulation in GBM, and which METTL8 isoform(s) may influence GBM cell fate and malignancy remain elusive. Here, we investigated the role of METTL8 in regulating GBM stemness and tumorigenicity. In GSC, METTL8 is exclusively localized to the mitochondrial matrix where it installs m3C on mt-tRNAThr/Ser(UCN) for mitochondrial translation and respiration. High expression of METTL8 in GBM is attributed to histone variant H2AZ-mediated chromatin accessibility of HIF1α and portends inferior glioma patient outcome. METTL8 depletion impairs the ability of GSC to self-renew and differentiate, thus retarding tumor growth in an intracranial GBM xenograft model. Interestingly, METTL8 depletion decreases protein levels of HIF1α, which serves as a transcription factor for several receptor tyrosine kinase (RTK) genes, in GSC. Accordingly, METTL8 loss inactivates the RTK/Akt axis leading to heightened sensitivity to Akt inhibitor treatment. These mechanistic findings, along with the intimate link between METTL8 levels and the HIF1α/RTK/Akt axis in glioma patients, guided us to propose a HIF1α/Akt inhibitor combination which potently compromises GSC proliferation/self-renewal in vitro. Thus, METTL8 represents a new GBM dependency that is therapeutically targetable.

HIF-1α participates in the regulation of S100A16-HRD1-GSK3β/CK1α pathway in renal hypoxia injury

S100 calcium-binding protein 16 (S100A16) is implicated in both chronic kidney disease (CKD) and acute kidney injury (AKI). Previous research has shown that S100A16 contributes to AKI by facilitating the ubiquitylation and degradation of glycogen synthase kinase 3β (GSK3β) and casein kinase 1α (CK1α) through the activation of HMG-CoA reductase degradation protein 1 (HRD1). However, the mechanisms governing S100A16-induced HRD1 activation and the upregulation of S100A16 expression in renal injury are not fully understood. In this study, we observed elevated expression of Hypoxia-inducible Factor 1-alpha (HIF-1α) in the kidneys of mice subjected to ischemia-reperfusion injury (IRI). S100A16 deletion attenuated the increased HIF-1α expression induced by IRI. Using a S100A16 knockout rat renal tubular epithelial cell line (NRK-52E cells), we found that S100A16 knockout effectively mitigated apoptosis during hypoxic reoxygenation (H/R) and cell injury induced by TGF-β1. Our results revealed that H/R injuries increased both protein and mRNA levels of HIF-1α and HRD1 in renal tubular cells. S100A16 knockout reversed the expressions of HIF-1α and HRD1 under H/R conditions. Conversely, S100A16 overexpression in NRK-52E cells elevated HIF-1α and HRD1 levels. HIF-1α overexpression increased HRD1 and β-catenin while decreasing GSK-3β. HIF-1α inhibition restored HRD1 and β-catenin upregulation and GSK-3β downregulation by cellular H/R injury. Notably, Chromatin immunoprecipitation (ChIP) and luciferase reporter assays demonstrated HIF-1α binding signals on the HRD1 promoter, and luciferase reporter gene assays confirmed HIF-1α‘s transcriptional regulation of HRD1. Additionally, we identified Transcription Factor AP-2 Beta (TFAP2B) as the upregulator of S100A16. ChIP and luciferase reporter assays confirmed TFAP2B as a transcription factor for S100A16. In summary, this study identifies TFAP2B as the transcription factor for S100A16 and demonstrates HIF-1α regulation of HRD1 transcription within the S100A16-HRD1-GSK3β/CK1α pathway during renal hypoxia injury. These findings provide crucial insights into the molecular mechanisms of kidney injury, offering potential avenues for therapeutic intervention.

CD8 Cell PHD2 Deficiency Amplifies Pressure Overload-Induced Cardiac Inflammation through Metabolic Reprogramming of CD8 Cells

Prolyl hydroxylase domain (PHD) proteins function as oxygen sensors and regulate various cellular metabolism. PHD2 is well-known for its role in oxygen sensing and has been implicated in cardiac hypertrophy and fibrosis through HIF-2α. However, the specific impact and the mechanism of CD8 cell PHD2 deficiency on cardiac inflammation and heart failure (HF) development remains unclear. Here, we explored the role of CD8 cell-specific PHD2 deficiency (CD8-PHD2 KO) in HF development by using transverse aortic constriction (TAC) mouse model. Our findings reveal that CD8 PHD2 knockout exacerbated TAC-induced left ventricular (LV) hypertrophy, as evidenced by increased LV weight relative to bodyweight or tibial length. CD8-PHD2 KO also leads to a significant increase in lung and right ventricular weight relative to bodyweight or tibial length following TAC. Furthermore, CD8-PHD2 KO worsens TAC-induced reductions in LV ejection fraction, LV fractional shortening, and LV dilatation. Additionally, CD8-PHD2 KO exacerbates TAC-induced LV cardiomyocyte hypertrophy, fibrosis, and immune cell infiltration. Moreover, our study demonstrated that CD8-PHD2 KO amplified the infiltration and activation of antigen-presenting cells, CD4 T cells, and CD8 T cells in the heart and lungs after TAC. At the molecular level, we characterized the PHD2-deficient CD8 cells showed typical features of anaerobic glycolysis, which were paralleled by augmented hypoxia-inducible factor 1α (HIF-1α) protein levels. Collectively, these results highlight the critical role of PHD2 in CD8 cells in regulating cardiac inflammation and HF development in response to systolic overload. National Institutes of Health Project Number 5R01HL161085-02. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Heat shock protein 90 and prolyl hydroxylase 2 co-regulate hypoxia-inducible factor-1α expression in porcine small intestinal epithelial cells under heat stress

Heat stress (HS) poses a substantial threat to animal growth and development, resulting in declining performance and economic losses. The intestinal system is susceptible to HS and undergoes intestinal hyperthermia and pathological hypoxia. Hypoxia-inducible factor-1α (HIF-1α), a key player in cellular hypoxic adaptation, is influenced by prolyl-4-hydroxylase 2 (PHD2) and heat shock protein 90 (HSP90). However, the comprehensive regulation of HIF-1α in the HS intestine remains unclear. This study aims to explore the impact of HS on pig intestinal mucosa and the regulatory mechanism of HIF-1α. Twenty-four Congjiang Xiang pigs were divided into the control and five HS-treated groups (6, 12, 24, 48, and 72 h). Ambient temperature and humidity were maintained in a thermally-neutral state (temperature–humidity index (THI) < 74) in the control group, whereas the HS group experienced moderate HS (78 < THI <84). Histological examination revealed villus exfoliation after 12 h of HS in the duodenum, jejunum, and ileum, with increasing damage as HS duration extended. The villus height to crypt depth ratio (V/C) decreased and goblet cell number increased with prolonged HS. Quantitative real-time PCR, Western blot, and immunohistochemistry analysis indicated increased expression of HIF-1α and HSP90 in the small intestine with prolonged HS, whereas PHD2 expression decreased. Further investigation in IPEC-J2 cells subjected to HS revealed that overexpressing PHD2 increased PHD2 mRNA and protein expression, while it decreases HIF-1α. Conversely, interfering with HSP90 expression substantially decreased both HSP90 and HIF-1α mRNA and protein levels. These results suggest that HS induces intestinal hypoxia with concomitant small intestinal mucosal damage. The expression of HIF-1α in HS-treated intestinal epithelial cells may be co-regulated by HSP90 and PHD2 and is possibly linked to intestinal hyperthermia and hypoxia.

Role of mTOR and HIF-1α in LMP2A-mediated increase in ATP production

Abstract Numerous studies indicate that latency proteins from Epstein-Barr virus contribute not only to the development, but also the survival of B cell lymphomas. Our laboratory has demonstrated that LMP2A promotes B cell lymphoma survival by inducing the activation of STAT3. More recently, pathways that link STAT3 activation with increased cellular metabolism suggested that LMP2A may increase B cell lymphoma ATP production via the mTOR-dependent activation of STAT3. Using LMP2A-negative and -positive B cell lymphoma cell lines, our data suggest that LMP2A increases ATP production in an mTOR-dependent pathway. However, the addition of the STAT3 inhibitor, STATTIC, did not impact the LMP2A-mediated increase in ATP production. Further investigation indicated that LMP2A-mediated activation of mTOR results in increases in HIF-1α protein, but not RNA, that are required for the enhancements in ATP production. Finally, our data demonstrate that LMP2A requires the activation of phosphorylated p70 ribosomal s6 kinase and 4E-BP1 to increase protein levels of HIF-1α that are required to increase ATP levels in LMP2A-expressing cell lines. Taken together, our data suggest that LMP2A gives lymphoma cells a competitive advantage to produce more ATP through increases in HIF-1α that are mTOR and p70s6K/4E-BP-1 dependent.

The Essential Role of PGF2α/PTGFR in Molding Endometrial Breakdown and Vascular Dynamics, Regulated by HIF-1α in a Mouse Menstrual-like Model.

In women of childbearing age, extensive decidualization, shedding and remodeling of the endometrium during the menstrual cycle are fundamental for successful pregnancy. The role of prostaglandins (PGs) in menstruation has long been proposed in humans, and the rate-limiting enzyme cyclooxygenase was shown to play a key role in endometrial breakdown and shedding in a mouse menstrual-like model in our previous study. However, the specific types of PGs involved and their respective roles remain unclear. Therefore, our objective was to investigate the mechanism through which PGs regulate endometrial disintegration. In this study, the microscopy was observed by HE; the protein levels of prostaglandins E1 (PGE1), prostaglandins E2 (PGE2), prostaglandin F2α (PGF2α) and Prostaglandin I2 (PGI2) were detected by ELISA; the mRNA level of Pfgfr2, Vascular Endothelial Growth Factor(Vegf), Angiostatin and Hypoxia inducible factor-1α (Hif1α) were examined by real-time PCR; PTGFR Receptor (PTGFR), VEGF, Angiostatin and HIF-1α protein levels were investigated by western blotting; the locations of protein were observed by Immunohistochemistry; HIF-1α binding PTGFR promoter was detected by Chromatin Immunoprecipitation (ChIP) and real-time PCR. We found that the concentrations of PGE1, PGE2, and PGF2α all increased significantly during this process. Furthermore, Ptgfr mRNA increased soon after Progesterone (P4) withdrawal, and PTGFR protein levels increased significantly during abundant endometrial breakdown and shedding processes. PTGFR inhibitors AL8810 significantly suppressed endometrial breakdown and shedding, promoted Angiostatin expression, and reduced VEGF-A expressions and vascular permeability. And HIF-1α and PTGFR were mainly located in the luminal/gland epithelium, vascular endothelium, and pre-decidual zone. Interestingly, HIF-1α directly bound to Ptgfr promoter. Moreover, a HIF-1α inhibitor 2-methoxyestradiol (2ME) significantly reduced PTGFR expression and suppressed endometrial breakdown which was in accord with PTGFR inhibitor's effect. Similar changes occurred in human stromal cells relevant to menstruation in vitro. Our study provides evidence that PGF2α/PTGFR plays a vital role in endometrial breakdown via vascular changes that are regulated by HIF-1α during menstruation.

Salvianic acid A sodium facilitates cardiac microvascular endothelial cell proliferation by enhancing the hypoxia-inducible factor-1 alpha/vascular endothelial growth factor signalling pathway post-myocardial infarction.

Cardiac microvascular endothelial cells (CMECs) are important cells surrounding the cardiomyocytes in the heart that maintain microenvironment homeostasis. Salvianic acid A sodium (SAAS) has been reported to prevent myocardial infarction (MI) injury. However, the role of SAAS on CMEC proliferation remains unclear. CEMCs exposed to oxygen glucose deprivation (OGD) were used to explore the angiogenic abilities of SAAS. In vivo, C57BL/6 mice were divided into three groups: sham, MI and SAAS + MI groups. Compared to OGD group, SAAS led to a reduction in the apoptotic rate and an increase of the proliferation in vitro. Additionally, SAAS increased the protein levels of Bcl2, HIF-1α and vascular endothelial growth factor (VEGF) with the reduction of Bax. In terms of the specific mechanisms, SAAS might inhibit HIF-1α ubiquitination and enhance the HIF-1α/VEGF signalling pathway to increase CMEC proliferation. Furthermore, SAAS increased the density of vessels, inhibited myocardial fibrosis and improved cardiac dysfunction in vivo. The present study has revealed that SAAS could potentially be used as an active substance to facilitate CMEC proliferation post-MI.

High-fat diet consumption promotes adolescent neurobehavioral abnormalities and hippocampal structural alterations via microglial overactivation accompanied by an elevated serum free fatty acid concentration

Mounting evidence suggests that high-fat diet (HFD) consumption increases the risk for depression, but the neurophysiological mechanisms involved remain to be elucidated. Here, we demonstrated that HFD feeding of C57BL/6J mice during the adolescent period (from 4 to 8 weeks of age) resulted in increased depression- and anxiety-like behaviors concurrent with changes in neuronal and myelin structure in the hippocampus. Additionally, we showed that hippocampal microglia in HFD-fed mice assumed a hyperactive state concomitant with increased PSD95-positive and myelin basic protein (MBP)-positive inclusions, implicating microglia in hippocampal structural alterations induced by HFD consumption. Along with increased levels of serum free fatty acids (FFAs), abnormal deposition of lipid droplets and increased levels of HIF-1α protein (a transcription factor that has been reported to facilitate cellular lipid accumulation) within hippocampal microglia were observed in HFD-fed mice. The use of minocycline, a pharmacological suppressor of microglial overactivation, effectively attenuated neurobehavioral abnormalities and hippocampal structural alterations but barely altered lipid droplet accumulation in the hippocampal microglia of HFD-fed mice. Coadministration of triacsin C abolished the increases in lipid droplet formation, phagocytic activity, and ROS levels in primary microglia treated with serum from HFD-fed mice. In conclusion, our studies demonstrate that the adverse influence of early-life HFD consumption on behavior and hippocampal structure is attributed at least in part to microglial overactivation that is accompanied by an elevated serum FFA concentration and microglial aberrations represent a potential preventive and therapeutic target for HFD-related emotional disorders.

Abstract LB049: Isoharpontigenin inhibits migration and invasion of lung cancer cells through MEG3/EGFR pathway

Abstract Lung cancer is the second most common cancer in both men and women in the United States. Even though treatments including chemotherapy, targeted therapy, and immunotherapy are available, lung cancer has been the leading cause of cancer deaths. The discovery and evaluation of new alternative medications targeting lung cancer are tremendously important for reducing lung cancer mortality. Phytochemicals are very desirable chemotherapeutic agents because of their greater safety profile. Isorhapontigenin (ISO), one of the oral bioavailable dietary stilbenes, can be found in various natural resources. Our result showed that ISO treatment suppressed the invasion and migration of human lung cancer cell lines A549, H23, and H1299 cells. Long non-coding RNA Maternally Expressed Gene 3 (MEG3), a tumor suppressor, was downregulated or lost in various primary human tumor tissues and cancer cell lines. The low expression of MEG3 is correlated with poor prognosis in non-small cell lung cancer (NSCLC). Our results showed that ISO treatment elevated MEG3 levels in these lung cancer cell lines. One of the major genetic causes of lung cancer is mutations in the epidermal growth factor receptor (EGFR) receptor tyrosine kinase, resulting in activation of EGFR which activates several signaling pathways involved in cell proliferation, drug sensitivity, and angiogenesis. Our results showed that ISO decreased the phosphorylation and protein levels of EGFR in A549 cells. Hypoxia-inducible factor-1α (HIF-1α), a transcription factor, regulates the activation of several genes involved in cell proliferation, angiogenesis, invasion, and metastasis. Our results showed that ISO decreased HIF-1α protein levels. Overexpression of MEG3 reduced p-EGFR and HIF-1α, indicating MEG3 negatively regulated EGFR and HIF-1α. Our data also showed that inhibition of EGFR by its tyrosine inhibitor decreased HIF-1α, suggesting that EGFR positively regulates HIF-1α. In cancer cells, Epithelial-Mesenchymal Transition(EMT) endows cells with increased invasiveness and tumor-initiating capacity, contributing to metastasis and resistance to therapeutics. Slug, one of the EMT transcription factors maintains cell plasticity during carcinogenesis. Our results showed that ISO treatment decreased Slugprotein levels in A549 and H23 cells. Transcription factor SOX2 regulates cancer cell proliferation, EMT, migration, invasion, metastasis, tumor initiation, cancer stem cell formation as well as resistance to apoptosis and therapy. Our results showed that ISO decreased SOX2 expression. Knockdown of MEG3 increased the expressions of Slug and SOX2, indicating that MEG3 negatively regulates Slug and SOX2. In conclusion, ISO elevated MEG3, inhibiting EGFR, HIF-1α, Slug, and SOX2, suppressing the migration and invasion of lung cancer cells. Citation Format: Sophia Shi, Zhuo Zhang, Jingxia Li, Huailu Tu, Max Costa. Isoharpontigenin inhibits migration and invasion of lung cancer cells through MEG3/EGFR pathway [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr LB049.

Leucine improves thiram-induced tibial dyschondroplasia and gut microbiota dysbiosis in broilers

Thiram, a commonly used agricultural insecticide and fungicide, has been found to cause tibial dyschondroplasia (TD) in broilers, leading to substantial economic losses in the poultry industry. In this study, we aimed to investigate the mechanism of action of leucine in mitigating thiram-induced TD and leucine effects on gut microbial diversity. Broiler chickens were randomly divided into five equal groups: control group (standard diet), thiram-induced group (thiram 80 mg/kg from day 3 to day 7), and different concentrations of leucine groups (0.3%, 0.6%, 0.9% leucine from day 8 to day 18). Performance indicator analysis and tibial parameter analysis showed that leucine positively affected thiram-induced TD broilers. Additionally, mRNA expressions and protein levels of HIF-1α/VEGFA and Ihh/PTHrP genes were determined via quantitative real-time polymerase chain reaction and western blot. The results showed that leucine recovered lameness disorder by downregulating the expression of HIF-1α, VEGFA, and PTHrP while upregulating the expression of Ihh. Moreover, the 16 S rRNA sequencing revealed that the leucine group demonstrated a decrease in the abundance of harmful bacteria compared to the TD group, with an enrichment of beneficial bacteria responsible for producing short-chain fatty acids, including Alistipes, Paludicola, CHKCI002, Lactobacillus, and Erysipelatoclostridium. In summary, the current study suggests that leucine could improve the symptoms of thiram-induced TD and maintain gut microbiota homeostasis.