Citrullination modulation stabilizes HIF-1α to promote tumour progression.

Citrullination plays an essential role in various physiological or pathological processes, however, whether citrullination is involved in regulating tumour progression and the potential therapeutic significance have not been well explored. Here, we find that peptidyl arginine deiminase 4 (PADI4) directly interacts with and citrullinates hypoxia-inducible factor 1α (HIF-1α) at R698, promoting HIF-1α stabilization. Mechanistically, PADI4-mediated HIF-1αR698 citrullination blocks von Hippel-Lindau (VHL) binding, thereby antagonizing HIF-1α ubiquitination and subsequent proteasome degradation. We also show that citrullinated HIF-1αR698, HIF-1α and PADI4 are highly expressed in hepatocellular carcinoma (HCC) tumour tissues, suggesting a potential correlation between PADI4-mediated HIF-1αR698 citrullination and cancer development. Furthermore, we identify that dihydroergotamine mesylate (DHE) acts as an antagonist of PADI4, which ultimately suppresses tumour progression. Collectively, our results reveal citrullination as a posttranslational modification related to HIF-1α stability, and suggest that targeting PADI4-mediated HIF-1α citrullination is a promising therapeutic strategy for cancers with aberrant HIF-1α expression.

ZNF740 facilitates the malignant progression of hepatocellular carcinoma via the METTL3/HIF­1A signaling axis.

Hepatocellular carcinoma (HCC) is the second leading cause of cancer­related death, and efficient treatments to facilitate recovery and enhance long­term outcomes are lacking. Zinc finger proteins (ZNFs), known as the largest group of transcription factors, have gained interest for their roles in HCC by stimulating the transcription of well­known tumor­causing genes. However, the specific roles and molecular mechanisms of ZNF740 in HCC remain unknown. The present study performed bioinformatics analysis and RNA­sequencing analysis of differentially expressed genes in HCC, detected ZNF740 expression levels in HCC using reverse transcription­quantitative PCR, western blotting and immunohistochemistry, and explored the effects of ZNF740 on the progression of liver cancer in vitro and in vivo using cellular functionality assays and cell­derived xenografts. In addition, a dual­luciferase reporter assay was performed to analyze the binding of ZNF740 with the METTL3 promoter. Furthermore, cell functionality experiments were performed to analyze whether ZNF740 promotes the proliferation of liver cancer cells in a METTL3­dependent manner. Bioinformatics and immunoprecipitation assays were further used to analyze the molecular mechanism of ZNF740 in liver cancer. The present study demonstrated that ZNF740 expression was upregulated in HCC. Mechanistically, overexpressed ZNF740 interacted with the methyltransferase­like 3 (METTL3) promoter and increased METTL3 expression, leading to the stabilization of hypoxia­inducible factor­1A (HIF1A) mRNA in an N6­methyladenosine/YTH N6­methyladenosine RNA­binding protein 1­dependent manner. Eventually, the ZNF740/METTL3/HIF1A signaling axis may facilitate the proliferation, invasion and metastasis of liver cancer via METTL3/HIF­1A signaling. The present findings revealed the important role of ZNF740 and suggested a potential therapeutic approach that might improve clinical therapies for liver cancer.

The p-MYH9/USP22/HIF-1α axis promotes lenvatinib resistance and cancer stemness in hepatocellular carcinoma.

Lenvatinib is a targeted drug used for first-line treatment of hepatocellular carcinoma (HCC). A deeper insight into the resistance mechanism of HCC against lenvatinib is urgently needed. In this study, we aimed to dissect the underlying mechanism of lenvatinib resistance (LR) and provide effective treatment strategies. We established an HCC model of acquired LR. Cell counting, migration, self-renewal ability, chemoresistance and expression of stemness genes were used to detect the stemness of HCC cells. Molecular and biochemical strategies such as RNA-sequencing, immunoprecipitation, mass spectrometry and ubiquitination assays were used to explore the underlying mechanisms. Patient-derived HCC models and HCC samples from patients were used to demonstrate clinical significance. We identified that increased cancer stemness driven by the hypoxia-inducible factor-1α (HIF-1α) pathway activation is responsible for acquired LR in HCC. Phosphorylated non-muscle myosin heavy chain 9 (MYH9) at Ser1943, p-MYH9 (Ser1943), could recruit ubiquitin-specific protease 22 (USP22) to deubiquitinate and stabilize HIF-1α in lenvatinib-resistant HCC. Clinically, p-MYH9 (Ser1943) expression was upregulated in HCC samples, which predicted poor prognosis and LR. A casein kinase-2 (CK2) inhibitor and a USP22 inhibitor effectively reversed LR in vivo and in vitro. Therefore, the p-MYH9 (Ser1943)/USP22/HIF-1α axis is critical for LR and cancer stemness. For the diagnosis and treatment of LR in HCC, p-MYH9 (Ser1943), USP22, and HIF-1α might be valuable as novel biomarkers and targets.

NF-κB and TET2 promote macrophage reprogramming in hypoxia that overrides the immunosuppressive effects of the tumor microenvironment.

Macrophages orchestrate tissue homeostasis and immunity. In the tumor microenvironment (TME), macrophage presence is largely associated with poor prognosis because of their reprogramming into immunosuppressive cells. We investigated the effects of hypoxia, a TME-associated feature, on the functional, epigenetic, and transcriptional reprogramming of macrophages and found that hypoxia boosts their immunogenicity. Hypoxic inflammatory macrophages are characterized by a cluster of proinflammatory genes undergoing ten-eleven translocation-mediated DNA demethylation and overexpression. These genes are regulated by NF-κB, while HIF1α dominates the transcriptional reprogramming, demonstrated through ChIP-seq and pharmacological inhibition. In bladder and ovarian carcinomas, hypoxic inflammatory macrophages are enriched in immune-infiltrated tumors, correlating with better patient prognoses. Coculture assays and cell-cell communication analyses support that hypoxic-activated macrophages enhance T cell-mediated responses. The NF-κB-associated hypomethylation signature is displayed by a subset of hypoxic inflammatory macrophages, isolated from ovarian tumors. Our results challenge paradigms regarding the effects of hypoxia on macrophages and highlight actionable target cells to modulate anticancer immune responses.

HIF-1α knockdown attenuates inflammation and oxidative stress in ischemic stroke male rats via CXCR4/NF-κB pathway.

BACKGROUND: Hypoxia inducible factor-1α (HIF-1α) is a sensitive indicator of oxygen homeostasis, of which the expression elevates following hypoxia/ischemia. This study reveals the specific mechanisms underlying the effects of HIF-1α on ischemic stroke (IS). METHODS: IS model was established using middle cerebral artery occlusion (MCAO)-modeled male rats and oxygen glucose deprivation/reoxygenation (OGD/R)-treated mice hippocampal cells HT22, followed by the silencing of HIF-1α and the overexpression of C-X-C motif chemokine receptor 4 (CXCR4) and nuclear factor-kappa B (NF-κB). Following the surgery, Garcia's grading scale was applied for neurological evaluation. Cerebral infarcts and injuries were visualized using 2,3,5-triphenyltetrazolium chloride and hematoxylin-eosin staining. The levels of tumor necrosis factor-α, Interleukin (IL)-6, IL-1ß, malondialdehyde, and 8-hydroxy-2'-deoxyguanosine, were calculated via ELISA. MTT assay and lactate dehydrogenase (LDH) assay kit were adopted to determine the viability and cytotoxicity of OGD/R-modeled cells. Reactive oxygen species (ROS) generation was evaluated using a 2'-7'dichlorofluorescin diacetate (DCFH-DA) probe. The levels of HIF-1α, CXCR4, and NF-κB p65 were quantified via Western blot and immunofluorescence, respectively. RESULTS: HIF-1α knockdown improved Garcia's score, attenuated the cerebral infarct, inflammation, and ROS generation, and alleviated the levels of inflammatory cytokines and CXCR4/NF-κB p65 in MCAO-modeled rats. Such effects were reversed following the overexpression of CXCR4 and NF-κB. Also, in OGD/R-treated HT22 cells, HIF-1α silencing diminished the cytotoxicity and ROS production and reduced the expressions of CXCR4/NF-κB p65, while promoting viability. However, CXCR4/NF-κB p65 overexpression did the opposite. CONCLUSION: HIF-1α knockdown alleviates inflammation and oxidative stress in IS through the CXCR4/NF-κB pathway.

PHD2 safeguards modest mesendoderm development.

PHD2 is essential in modulating HIF-1α levels upon oxygen fluctuations. Hypoxia, a hallmark of uterus, and HIF-1α have recently emerged as opposing regulators of mesendoderm specification, suggesting a role for PHD2 therein. We found that PHD2 expression initially covered the epiblast and gradually receded from the primitive streak, which was identical to hypoxia and exclusive to HIF-1α. The investigations performed in mESCs, embryoids, and mouse embryos together demonstrated that PHD2 negatively regulated mesendoderm specification. Single-cell RNA sequencing revealed that PHD2 governed the transition from epiblast to mesendoderm. The downstream effect of PHD2 relied on the HIF-1α regulated Wnt/ß-catenin pathway, while it was regulated upstream by miR-429. In summary, our research highlights PHD2's essential role in mesendoderm specification and its interactions with hypoxia and HIF-1α.

IL-6 signaling accelerates iron overload by upregulating DMT1 in endothelial cells to promote aortic dissection.

Aortic dissection (AD), caused by tearing of the intima and avulsion of the aortic media, is a severe threat to patient life and organ function. Iron is closely related to dissection formation and organ injury, but the mechanism of iron ion transport disorder in endothelial cells (ECs) remains unclear. We identified the characteristic EC of dissection with iron overload by single-cell RNA sequencing data. After intersecting iron homeostasis and differentially expressed genes, it was found that hypoxia-inducible factor-1α (HIF-1α) and divalent metal transporter 1 (DMT1) are key genes for iron ion disorder. Subsequently, IL-6R was identified as an essential reason for the JAK-STAT activation, a classical iron regulation pathway, through further intersection and validation. In in vivo and in vitro, both high IL-6 receptor expression and elevated IL-6 levels promote JAK1-STAT3 phosphorylation, leading to increased HIF-1α protein levels. Elevated HIF-1α binds explicitly to the 5'-UTR sequence of the DMT1 gene and transcriptionally promotes DMT1 expression, thereby increasing Fe2+ accumulation and endoplasmic reticulum stress (ERS). Blocking IL-6R and free iron with deferoxamine and tocilizumab significantly prolonged survival and reduced aortic and organ damage in dissection mice. A comparison of perioperative data between AD patients and others revealed that high free iron, IL-6, and ERS levels are characteristics of AD patients and are correlated with prognosis. In conclusion, activated IL-6/JAK1/STAT3 signaling axis up-regulates DMT1 expression by increasing HIF-1α, thereby increasing intracellular Fe2+ accumulation and tissue injury, which suggests a potential therapeutic target for AD.

Activating UCHL1 through the CRISPR activation system promotes cartilage differentiation mediated by HIF-1α/SOX9.

Developing strategies to enhance cartilage differentiation in mesenchymal stem cells and preserve the extracellular matrix is crucial for successful cartilage tissue reconstruction. Hypoxia-inducible factor-1α (HIF-1α) plays a pivotal role in maintaining the extracellular matrix and chondrocyte phenotype, thus serving as a key regulator in chondral tissue engineering strategies. Recent studies have shown that Ubiquitin C-terminal hydrolase L1 (UCHL1) is involved in the deubiquitylation of HIF-1α. However, the regulatory role of UCHL1 in chondrogenic differentiation has not been investigated. In the present study, we initially validated the promotive effect of UCHL1 expression on chondrogenesis in adipose-derived stem cells (ADSCs). Subsequently, a hybrid baculovirus system was designed and employed to utilize three CRISPR activation (CRISPRa) systems, employing dead Cas9 (dCas9) from three distinct bacterial sources to target UCHL1. Then UCHL1 and HIF-1α inhibitor and siRNA targeting SRY-box transcription factor 9 (SOX9) were used to block UCHL1, HIF-1α and SOX9, respectively. Cartilage differentiation and chondrogenesis were measured by qRT-PCR, immunofluorescence and histological staining. We observed that the CRISPRa system derived from Staphylococcus aureus exhibited superior efficiency in activating UCHL1 compared to the commonly used the CRISPRa system derived from Streptococcus pyogenes. Furthermore, the duration of activation was extended by utilizing the Cre/loxP-based hybrid baculovirus. Moreover, our findings show that UCHL1 enhances SOX9 expression by regulating the stability and localization of HIF-1α, which promotes cartilage production in ADSCs. These findings suggest that activating UCHL1 using the CRISPRa system holds significant potential for applications in cartilage regeneration.

HIF1A-AS2 promotes the metabolic reprogramming and progression of colorectal cancer via miR-141-3p/FOXC1 axis.

lncRNA can regulate tumorigenesis development and distant metastasis of colorectal cancer (CRC). However, the detailed molecular mechanisms are still largely unknown. Using RNA-sequencing data, RT-qPCR, and FISH assay, we found that HIF1A-AS2 was upregulated in CRC tissues and associated with poor prognosis. Functional experiments were performed to determine the roles of HIF1A-AS2 in tumor progression and we found that HIF1A-AS2 can promote the proliferation, metastasis, and aerobic glycolysis of CRC cells. Mechanistically, HIF1A-AS2 can promote FOXC1 expression by sponging miR-141-3p. SP1 can transcriptionally activate HIF1A-AS2. Further, HIF1A-AS2 can be packaged into exosomes and promote the malignant phenotype of recipient tumor cells. Taken together, we discovered that SP1-induced HIF1A-AS2 can promote the metabolic reprogramming and progression of CRC via miR-141-3p/FOXC1 axis. HIF1A-AS2 is a promising diagnostic marker and treatment target in CRC.

TCEB2/HIF1A signaling axis promotes chemoresistance in ovarian cancer cells by enhancing glycolysis and angiogenesis.

Ovarian cancer is an extremely malignant gynaecological tumour with a poor patient prognosis and is often associated with chemoresistance. Thus, exploring new therapeutic approaches to improving tumour chemosensitivity is important. The expression of transcription elongation factor B polypeptide 2 (TCEB2) gene is reportedly upregulated in ovarian cancer tumour tissues with acquired resistance, but the specific mechanism involved in tumour resistance remains unclear. In this study, we found that TCEB2 was abnormally highly expressed in cisplatin-resistant tumour tissues and cells. TCEB2 silencing also inhibited the growth and glycolysis of SKOV-3/cisplatin (DDP) and A2780/DDP cells. We further incubated human umbilical vein endothelial cells (HUVECs) with culture supernatants from cisplatin-resistant cells having TCEB2 knockdown. Results revealed that the migration, invasion, and angiogenesis of HUVECs were significantly inhibited. Online bioinformatics analysis revealed that the hypoxia-inducible factor-1A (HIF-1A) protein may bind to TCEB2, and TCEB2 silencing inhibited SKOV-3/DDP cell growth and glycolysis by downregulating HIF1A expression. Similarly, TCEB2 promoted HUVEC migration, invasion, and angiogenesis by upregulating HIF1A expression. In vivo experiments showed that TCEB2 silencing enhanced the sensitivity of ovarian cancer nude mice to cisplatin and that TCEB2 knockdown inhibited the glycolysis and angiogenesis of tumour cells. Our findings can serve as a reference for treating chemoresistant ovarian cancer.

HOTAIR Promotes the Hyperactivation of PI3K/Akt and Wnt/ß-Catenin Signaling Pathways via PTEN Hypermethylation in Cervical Cancer.

The mechanisms underlying the sustained activation of the PI3K/AKT and Wnt/ß-catenin pathways mediated by HOTAIR in cervical cancer (CC) have not been extensively described. To address this knowledge gap in the literature, we explored the interactions between these pathways by driving HOTAIR expression levels in HeLa cells. Our findings reveal that HOTAIR is a key regulator in sustaining the activation of both signaling pathways. Specifically, altering HOTAIR expression-either by knockdown or overexpression-significantly influenced the transcriptional activity of the PI3K/AKT and Wnt/ß-catenin pathways. Additionally, we discovered that HIF1α directly induces HOTAIR transcription, which in turn leads to the epigenetic silencing of the PTEN promoter via DNMT1. This process leads to the sustained activation of both pathways, highlighting a novel regulatory axis involving HOTAIR and HIF1α in cervical cancer. Our results suggest a new model in which HOTAIR sustains reciprocal activation of the PI3K/AKT and Wnt/ß-catenin pathways through the HOTAIR/HIF1α axis, thereby contributing to the oncogenic phenotype of cervical cancer.

Hypoxia Abrogates Tumor-Suppressive Activities of C/EBPδ in Pancreatic Cancer.

Pancreatic ductal adenocarcinoma (PDAC) is a dismal disease with a low 5-year survival rate of only 13%. Despite intense research efforts, PDAC remains insufficiently understood. In part, this is attributed to opposing effects of key players being unraveled, including the stroma but also molecules that act in a context-dependent manner. One such molecule is the transcription factor C/EBPδ, where we recently showed that C/EBPδ exerts tumor-suppressive effects in PDAC cells in vitro. To better understand the role of C/EBPδ in different contexts and the development of PDAC, we here build on these findings and assess the effect of C/EBPδ in a PDAC model in mice. We establish that the lack of oxygen in vivo-hypoxia-counteracts the tumor-suppressive effects of C/EBPδ, and identify a reciprocal feedback loop between C/EBPδ and HIF-1α. RNA sequencing of C/EBPδ-induced cells under hypoxia also suggests that the growth-limiting effects of C/EBPδ decrease with oxygen tension. Consequently, in vitro proliferation assays reveal that the tumor-suppressive activities of C/EBPδ are abrogated due to hypoxia. This study demonstrates the importance of considering major physiological parameters in preclinical approaches.

Enhanced tumor response to adoptive T cell therapy with PHD2/3-deficient CD8 T cells.

While adoptive cell therapy has shown success in hematological malignancies, its potential against solid tumors is hindered by an immunosuppressive tumor microenvironment (TME). In recent years, members of the hypoxia-inducible factor (HIF) family have gained recognition as important regulators of T-cell metabolism and function. The role of HIF signalling in activated CD8 T cell function in the context of adoptive cell transfer, however, has not been explored in full depth. Here we utilize CRISPR-Cas9 technology to delete prolyl hydroxylase domain-containing enzymes (PHD) 2 and 3, thereby stabilizing HIF-1 signalling, in CD8 T cells that have already undergone differentiation and activation, modelling the T cell phenotype utilized in clinical settings. We observe a significant boost in T-cell activation and effector functions following PHD2/3 deletion, which is dependent on HIF-1α, and is accompanied by an increased glycolytic flux. This improvement in CD8 T cell performance translates into an enhancement in tumor response to adoptive T cell therapy in mice, across various tumor models, even including those reported to be extremely resistant to immunotherapeutic interventions. These findings hold promise for advancing CD8 T-cell based therapies and overcoming the immune suppression barriers within challenging tumor microenvironments.

Hypoxia and Foxn1 alter the proteomic signature of dermal fibroblasts to redirect scarless wound healing to scar-forming skin wound healing in Foxn1-/- mice.

BACKGROUND: Foxn1-/- deficient mice are a rare model of regenerative skin wound healing among mammals. In wounded skin, the transcription factor Foxn1 interacting with hypoxia-regulated factors affects re-epithelialization, epithelial-mesenchymal transition (EMT) and dermal white adipose tissue (dWAT) reestablishment and is thus a factor regulating scar-forming/reparative healing. Here, we hypothesized that transcriptional crosstalk between Foxn1 and Hif-1α controls the switch from scarless (regenerative) to scar-present (reparative) skin wound healing. To verify this hypothesis, we examined (i) the effect of hypoxia/normoxia and Foxn1 signalling on the proteomic signature of Foxn1-/- (regenerative) dermal fibroblasts (DFs) and then (ii) explored the effect of Hif-1α or Foxn1/Hif-1α introduced by a lentiviral (LV) delivery vector to injured skin of regenerative Foxn1-/- mice with particular attention to the remodelling phase of healing. RESULTS: We showed that hypoxic conditions and Foxn1 stimulation modified the proteome of Foxn1-/- DFs. Hypoxic conditions upregulated DF protein profiles, particularly those related to extracellular matrix (ECM) composition: plasminogen activator inhibitor-1 (Pai-1), Sdc4, Plod2, Plod1, Lox, Loxl2, Itga2, Vldlr, Ftl1, Vegfa, Hmox1, Fth1, and F3. We found that Pai-1 was stimulated by hypoxic conditions in regenerative Foxn1-/- DFs but was released by DFs to the culture media exclusively upon hypoxia and Foxn1 stimulation. We also found higher levels of Pai-1 protein in DFs isolated from Foxn1+/+ mice (reparative/scar-forming) than in DFs isolated from Foxn1-/- (regenerative/scarless) mice and triggered by injury increase in Foxn1 and Pai-1 protein in the skin of mice with active Foxn1 (Foxn1+/+ mice). Then, we demonstrated that the introduction of Foxn1 and Hif-1α via lentiviral injection into the wounded skin of regenerative Foxn1-/- mice activates reparative/scar-forming healing by increasing the wounded skin area and decreasing hyaluronic acid deposition and the collagen type III to I ratio. We also identified a stimulatory effect of LV-Foxn1 + LV-Hif-1α injection in the wounded skin of Foxn1-/- mice on Pai-1 protein levels. CONCLUSIONS: The present data highlight the effect of hypoxia and Foxn1 on the protein profile and functionality of regenerative Foxn1-/- DFs and demonstrate that the introduction of Foxn1 and Hif-1α into the wounded skin of regenerative Foxn1-/- mice activates reparative/scar-forming healing.

Adipose Tissue Hypoxia in Obesity: Clinical Reappraisal of Hypoxia Hypothesis.

Obese subjects exhibit lower adipose tissue oxygen consumption in accordance with the lower adipose tissue blood flow. Thereby, compared to lean subjects, obese individuals have almost half lower capillary density and more than half lower vascular endothelial growth factor (VEGF). The VEGF expression together with hypoxia-inducible transcription factor-1 alpha (HIF-1α) activity also requires phosphatidylinositol 3-kinase (PI3K) and mammalian target of rapamycin (mTOR)-mediated signaling. Especially HIF-1α is an important signaling molecule for hypoxia to induce the inflammatory responses. Hypoxia contributes to several biological functions, such as angiogenesis, cell proliferation, apoptosis, inflammation, and insulin resistance (IR). Pathogenesis of obesity-related comorbidities is attributed to intermittent hypoxia (IH), which is mostly observed in visceral obesity. Proinflammatory phenotype of the adipose tissue is a crucial link between IH and the development of IR. Inhibition of adaptive unfolded protein response (UPR) in hypoxia increases ß cell death. Moreover, deletion of HIF-1α worsens ß cell function. Oxidative stress, as well as the release of proinflammatory cytokines/adipokines in obesity, is proportional to the severity of IH. Reactive oxygen species (ROS) generation at mitochondria is responsible for propagation of the hypoxic signal; however, mitochondrial ROS production is required for hypoxic HIF-1α protein stabilization. Alterations in oxygen availability of adipose tissue directly affect the macrophage polarization and are responsible for the dysregulated adipocytokines production in obesity. Hypoxia both inhibits adipocyte differentiation from preadipocytes and macrophage migration from the hypoxic adipose tissue. Upon reaching a hypertrophic threshold beyond the adipocyte fat loading capacity, excess extracellular matrix (ECM) components are deposited, causing fibrosis. HIF-1α initiates the whole pathological process of fibrosis and inflammation in the obese adipose tissue. In addition to stressed adipocytes, hypoxia contributes to immune cell migration and activation which further aggravates adipose tissue fibrosis. Therefore, targeting HIF-1α might be an efficient way to suppress hypoxia-induced pathological changes in the ECM. The fibrosis score of adipose tissue correlates negatively with the body mass index and metabolic parameters. Inducers of browning/beiging adipocytes and adipokines, as well as modulations of matrix remodeling enzyme inhibitors, and associated gene regulators, are potential pharmacological targets for treating obesity.

Hypoxia-inducible factors in postnatal mouse molar dental pulp development: insights into expression patterns, localisation and metabolic pathways.

Hypoxia is relevant to several physiological and pathological processes and this also applies for the tooth. The adaptive response to lowering oxygen concentration is mediated by hypoxia-inducible factors (HIFs). Since HIFs were shown to participate in the promotion of angiogenesis, stem cell survival, odontoblast differentiation and dentin formation, they may play a beneficial role in the tooth reparative processes. Although some data were generated in vitro, little is known about the in vivo context of HIFs in tooth development. In order to contribute to this field, the mouse mandibular first molar was used as a model.The expression and in situ localisation of HIFs were examined at postnatal (P) days P0, P7, P14, using RT-PCR and immunostaining. The expression pattern of a broad spectrum of hypoxia-related genes was monitored by customised PCR Arrays. Metabolic aspects were evaluated by determination of the lactate level and mRNA expression of the mitochondrial marker Nd1.The results show constant high mRNA expression of Hif1a, increasing expression of Hif2a, and very low expression of Hif3a during early postnatal molar development. In the examined period the localisation of HIFs in the nuclei of odontoblasts and the subodontoblastic layer identified their presence during odontoblastic differentiation. Additionally, the lower lactate level and higher expression of mitochondrial Nd1 in advanced development points to decreasing glycolysis during differentiation. Postnatal nuclear localisation of HIFs indicates a hypoxic state in specific areas of dental pulp as oxygen demands depend on physiological events such as crown and root dentin mineralization.

Hyperoxia exposure induces ferroptosis and apoptosis by downregulating PLAGL2 and repressing HIF-1α/VEGF signaling pathway in newborn alveolar typeII epithelial cell.

BACKGROUD: Bronchopulmonary dysplasia (BPD) is one of the most important complications plaguing neonates and can lead to a variety of sequelae. the ability of the HIF-1α/VEGF signaling pathway to promote angiogenesis has an important role in neonatal lung development. METHOD: Newborn rats were exposed to 85% oxygen. The effects of hyperoxia exposure on Pleomorphic Adenoma Gene like-2 (PLAGL2) and the HIF-1α/VEGF pathway in rats lung tissue were assessed through immunofluorescence and Western Blot analysis. In cell experiments, PLAGL2 was upregulated, and the effects of hyperoxia and PLAGL2 on cell viability were evaluated using scratch assays, CCK-8 assays, and EDU staining. The role of upregulated PLAGL2 in the HIF-1α/VEGF pathway was determined by Western Blot and RT-PCR. Apoptosis and ferroptosis effects were determined through flow cytometry and viability assays. RESULTS: Compared with the control group, the expression levels of PLAGL2, HIF-1α, VEGF, and SPC in lung tissues after 3, 7, and 14 days of hyperoxia exposure were all decreased. Furthermore, hyperoxia also inhibited the proliferation and motility of type II alveolar epithelial cells (AECII) and induced apoptosis in AECII. Upregulation of PLAGL2 restored the proliferation and motility of AECII and suppressed cell apoptosis and ferroptosis, while the HIF-1α/VEGF signaling pathway was also revived. CONCLUSIONS: We confirmed the positive role of PLAGL2 and HIF-1α/VEGF signaling pathway in promoting BPD in hyperoxia conditions, and provided a promising therapeutic targets.

Aberrant HIF1- α and SIX-1 Expression is Associated with Poor Prognosis in Acute Myeloid Leukemia Patients with Isocitrate Dehydrogenase 1 Mutations.

BACKGROUND: IDH1 mutations are common in many cancers, however, their role in promoting the Warburg effect remains elusive. This study elucidates the putative involvement of mutant-IDH1 in regulating hypoxia-inducible factor (HIF1-α) and Sine-Oculis Homeobox-1 (SIX-1) expression. METHODOLOGY: Genetic screening was performed using the ARMS-PCR in acute myeloid leukemia (AML), brain, and breast cancer (BC) cohorts, while transcript expression was determined using qPCR. Further, a meta-analysis of risk factors associated with the R132 mutation was performed. RESULTS: Approximately 32% of AML and ∼60% of glioma cases were mutants, while no mutation was found in the BC cohort. 'AA' and TT' were associated with higher disease risk (OR = 12.18 & 4.68) in AML and had significantly upregulated IDH1 expression. Moreover, downregulated HIF1-α and upregulated SIX-1 expression was also observed in these patients, suggesting that mutant-IDH1 may alter glucose metabolism. Perturbed IDH1 and HIF-α levels exhibited poor prognosis in univariate and multivariate analysis, while age and gender were found to be contributory factors as well. Based on the ROC model, these had a good potential to be used as prognostic markers. A significant variation in frequencies of R132 mutations in AML among different populations was observed. Cytogenesis (R2 = 12.2%), NMP1 mutation status (R2 = 18.5%), and ethnic contributions (R2 = 73.21%) were critical moderators underlying these mutations. Women had a higher risk of R132 mutation (HR = 1.3, P < 0.04). The pooled prevalence was calculated to be 0.29 (95% CI 0.26-0.33, P < 0.01), indicating that IDH1 mutations are a significant prognostic factor in AML. CONCLUSION: IDH1 and HIF1-α profiles are linked to poor survival and prognosis, while high SIX-1 expression in IDH1 mutants suggests a role in leukemic transformation and therapy response in AML.

IDH1 mutations are common in many types of cancer, but scientists have not fully understood how they contribute to the Warburg effect - a process that alters glucose metabolism in cells. In this study, we evaluate the association between mutant-IDH1 and HIF1 as well as SIX-1 gene expression. We analyzed genetic data from patients with brain cancer, breast cancer, and acute myeloid leukemia (AML), and found that roughly 32% of AML cases and 60% of glioma cases had IDH1 mutations, while no mutations were found in breast cancer. Patients with mutant genotypes had a higher risk of disease and showed upregulated IDH1 expression. They also had downregulated HIF1 and upregulated SIX-1 expression, suggesting that mutant-IDH1 can change glucose metabolism in cancer cells. Patients with abnormal IDH1 and HIF1 levels were more likely to have a poor prognosis. Further, we identified several risk factors that can influence IDH1 mutations, including cytogenesis, NMP1 mutation status, and ethnicity. The researchers calculated that IDH1 mutations are a significant factor in predicting outcomes for AML.

[Mechanism of Liangfang Wenjing Decoction in treatment of hypoxia on endometriosis with cold coagulation and blood stasis by regulating CHCHD4 expression].

To explore the mechanism of Liangfang Wenjing Decoction regulating coiled-coil-helix coiled-coil-helix domain containing 4(CHCHD4) in the treatment of hypoxia on endometriosis(EMs) with cold coagulation and blood stasis. The rat model of cold coagulation and blood stasis syndrome was prepared by the ice-water bath method, and then the EMs model was established by autologous intimal transplantation. The rats were randomly divided into model group, low, medium, and high(4.7, 9.4, and 18.8 g·kg~(-1)) dose groups of Liangfang Wenjing Decoction, Shaofu Zhuyu Decoction group, and sham group, with 10 rats in each group. The rats were given intragastric administration for four weeks. During the modeling, the general condition and vaginal smear of rats were observed, and the blood flow of ears and uterus were detected by laser speckle contrast imaging(LSCI) to judge the syndrome of cold coagulation and blood stasis. After the administration, the general condition of the rats was observed, and the area of ectopic lesions was measured by caliper. The localization and expression of CHCHD4 and hypoxia inducible factors-1α(HIF-1α) were detected by immunohistochemistry, and the mRNA and protein expressions of CHCHD4 and HIF-1α were detected by real-time quantitative polymerase chain reaction(RT-qPCR) and Western blot. The primary culture of ectopic endometrial stromal cells(ESCs) from EMs patients was performed, and the CHCHD4 overexpression plasmid was constructed and transfected to establish the ESCs model of CHCHD4 overexpression. The cells were divided into the control group, CHCHD4 overexpression group, CHCHD4 overexpression+control serum group, and CHCHD4 overexpression+Liangfang Wenjing Decoction serum group. The protein expression of CHCHD4 and HIF-1α was detected by Western blot, and the glucose consumption and lactic acid level were detected. The cell proliferation was detected by MTT assay. The experiment found that compared with normal rats, the modeling rats showed symptoms of cold coagulation and blood stasis, such as mental malaise, reduced diet and drinking water, disordered estrous cycle, and blocked blood circulation in ears and uterine microvessels. Compared with the sham group, the ectopic lesions in the model group were uplifted, and the mRNA and protein expressions of CHCHD4 and HIF-1α were significantly increased(P<0.05). Compared with the model group, the symptoms of cold coagulation and blood stasis in each treatment group were improved, and the area of ectopic lesions was significantly reduced(P<0.05 or P<0.01). The mRNA and protein expression levels of CHCHD4 and HIF-1α were significantly decreased(P<0.05 or P<0.01). In the cell model, compared with the control group, the expression of CHCHD4, HIF-1α protein, glucose consumption, lactic acid level, and cell proliferation activity in the CHCHD4 overexpression group were significantly increased(P<0.01). Compared with the CHCHD4 overexpression group, there was no significant change in each index in the control serum group, while the protein expression of CHCHD4 and HIF-1α in the Liangfang Wenjing Decoction serum group was decreased significantly(P<0.05 or P<0.01). The glucose consumption, lactic acid level, and cell proliferation activity decreased significantly(P<0.01). It can be seen from the above that the therapeutic effect of Liangfang Wenjing Decoction on EMs with cold coagulation and blood stasis might be related to reducing the expression of CHCHD4 and then improving the hypoxia of ectopic lesions and ectopic ESCs.

[Effect of 2-phenylethyl-beta-glucopyranoside isolated from Huaizhong No. 1 Rehmannia glutinosa on hypoxic pulmonary hypertension by regulating PI3K/Akt/m TOR/HIF-1α pathway].

The study investigated the protective effect and mechanism of 2-phenylethyl-beta-glucopyranoside(Phe) from Huaizhong No.1 Rehmannia glutinosa on hypoxic pulmonary hypertension(PH), aiming to provide a theoretical basis for clinical treatment of PAH. Male C57BL/6N mice were randomly divided into normal group, model group, positive drug(bosentan, 100 mg·kg~(-1)) group, and low-and high-dose Phe groups(20 and 40 mg·kg~(-1)). Except for the normal group, all other groups were continuously subjected to model induction in a 10% hypoxic environment for 5 weeks, with oral administration for 14 days starting from the 3rd week. The cardiopulmonary function, right ventricular pressure, cough and asthma index, lung injury, cell apoptosis, oxidative stress-related indicators, immune cells, and phosphatidylinositol 3-kinase(PI3K)/protein kinase B(Akt)/mammalian target of rapamycin(mTOR)/hypoxic inducible factor 1α(HIF-1α) pathway-related proteins or mRNA levels were examined. Furthermore, hypoxia-induced pulmonary arterial smooth muscle cell(PASMC) were used to further explore the mechanism of Phe intervention in PH combined with PI3K ago-nist(740Y-P). The results showed that Phe significantly improved the cardiopulmonary function of mice with PH, decreased right ventricular pressure, cough and asthma index, and lung injury, reduced cell apoptosis, oxidative stress-related indicators, and nuclear levels of phosphorylated Akt(p-Akt) and phosphorylated mTOR(p-mTOR), inhibited the expression levels of HIF-1α and PI3K mRNA and proteins, and maintained the immune cell homeostasis in mice. Further mechanistic studies revealed that Phe significantly reduced the viability and migration ability of hypoxia-induced PASMC, decreased the expression of HIF-1α and PI3K proteins and nuc-lear levels of p-Akt and p-mTOR, and this effect was blocked by 740Y-P. Therefore, it is inferred that Phe may exert anti-PH effects by alleviating the imbalance of oxidative stress and apoptosis in lung tissues and regulating immune levels, and its mechanism may be related to the regulation of the PI3K/Akt/mTOR/HIF-1α pathway. This study is expected to provide drug references and research ideas for the treatment of PH.