Hypoxia-inducible factors and the response to hypoxic stress

Molecular mechanism of infectious spleen and kidney necrosis virus in manipulating the hypoxia-inducible factor pathway to augment virus replication

Infectious spleen and kidney necrosis virus (ISKNV), a member of the genus Megalocytivirus in the family Iridoviridae, can infect over 50 fish species and cause significant economic losses in Asia. Our previous study showed that hypoxia triggers the hypoxia-inducible factor pathway (HIF-pathway), leading to increased replication of ISKNV through promoting the upregulation of viral hypoxic response genes like orf077r. This study delved into the molecular mechanism of how ISKNV manipulates the HIF-pathway to enhance its replication. In vitro and in vivo experiments confirmed that ISKNV infection activated the HIF-pathway, which in turn promoted ISKNV replication. These findings suggest that ISKNV actively manipulates the HIF-pathway. Co-immunoprecipitation experiments revealed that the ISKNV-encoded protein VP077R interacts with the Von Hippel-Lindau (VHL) protein at the HIF-binding region, competitively inhibiting the interaction of HIF-1α with VHL. This prevents HIF degradation and activates the HIF-pathway. Furthermore, VP077R interacts with factor-inhibiting HIF (FIH), recruiting FIH and S-phase kinase-associated protein 1 (Skp1) to form an FIH - VP077R - Skp1 complex. This complex promotes FIH protein degradation via ubiquitination, further activating the HIF-pathway. These findings indicated that ISKNV takes over the HIF-pathway by releasing two "brakes" on this pathway (VHL and FIH) via VP077R, facilitating virus replication. We speculate that hypoxia initiates a positive feedback loop between ISKNV VP077R and the HIF pathway, leading to the outbreak of ISKNV disease. This work offers valuable insights into the complex interactions between the environment, host, and virus.

Electroacupuncture enhances cerebral blood perfusion by inhibiting HIF-1α in rat subarachnoid hemorrhage

OBJECTIVE

Cerebral blood perfusion (CBP) reduction is a prevalent complication following subarachnoid hemorrhage (SAH) in clinical practice, often associated with long-term cognitive impairment and prognosis. Electroacupuncture (EA), a widely utilized traditional Chinese therapy for central nervous system disorders, has demonstrated promising therapeutic effects. This study aims to investigate the therapeutic potential of EA in restoring CBP in SAH rats and to explore the mechanisms involving HIF-1α in this process.

METHODS

Rats were randomly assigned to one of five groups, including Sham, SAH, EA, EA + Saline, and EA + dimethyloxallyl glycine (DMOG) groups. EA treatment was administered for 10 min daily, while DMOG were intraperitoneally injected. Behavioral tests, cerebral blood flow monitoring, vascular thickness measurement, western blotting, and immunofluorescence staining were conducted to assess the therapeutic effects of EA on cerebral blood flow.

RESULTS

SAH resulted in elevated levels of HIF-1α, endothelin (ET), ICAM-1, P-SELECTIN, E-SELECTIN, and decreased level of eNOS in the brain. This led to cerebral vasospasm, decreased CBF, and cognitive deficits in the rat SAH model. EA intervention downregulated the expression of HIF-1α, ET, ICAM-1, P-SELECTIN, and E-SELECTIN, while increasing eNOS expression. This alleviated cerebral vasospasm, restored CBF, and improved cognitive function. However, the administration of the HIF-1α stabilizer (DMOG) counteracted the therapeutic effects of EA.

CONCLUSION

EA promotes the recovery of cerebral blood flow after SAH injury, attenuates cerebral vasospasm, and accelerates the recovery of cognitive dysfunction, and its mechanism of action may be related to the inhibition of the HIF-1α signaling pathway.

Endothelial specific prolyl hydroxylase domain-containing protein 2 deficiency attenuates aging-related obesity and exercise intolerance

Obesity and exercise intolerance greatly reduce the life quality of older people. Prolyl hydroxylase domain-containing protein 2 (PHD2) is an important enzyme in modulating hypoxia-inducible factor-alpha (HIF) protein. Using vascular endothelial cell-specific PHD2 gene knockout (PHD2 ECKO) mice, we investigated the role of endothelial PHD2 in aging-related obesity and exercise capacity. Briefly, PHD2 ECKO mice were obtained by crossing PHD2-floxed mice with VE-Cadherin (Cdh5)-Cre transgenic mice. The effect of PHD2 ECKO on obesity and exercise capacity in PHD2 ECKO mice and control PHD2f/f mice were determined in young mice (6 to 7 months) and aged mice (16-18 months). We found that aged PHD2 ECKO mice, but not young mice, exhibited a lean phenotype, characterized by lower fat mass, and its ratio to lean weight, body weight, or tibial length, while their food uptake was not reduced compared with controls. Moreover, as compared with aged control mice, aged PHD2 ECKO mice exhibited increased oxygen consumption at rest and during exercise, and the maximum rate of oxygen consumption (VO2 max) during exercise. Furthermore, as compared with corresponding control mice, both young and aged PHD2 ECKO mice demonstrated improved glucose tolerance and lower insulin resistance. Together, these data demonstrate that inhibition of vascular endothelial PHD2 signaling significantly attenuates aging-related obesity, exercise intolerance, and glucose intolerance.

Metabolic reprogramming in septic acute kidney injury: pathogenesis and therapeutic implications

Acute kidney injury (AKI) is a frequent and severe complication of sepsis and is characterized by significant mortality and morbidity. However, the pathogenesis of septic acute kidney injury (S-AKI) remains elusive. Metabolic reprogramming, which was originally referred to as the Warburg effect in cancer, is strongly related to S-AKI. At the onset of sepsis, both inflammatory cells and renal parenchymal cells, such as macrophages, neutrophils and renal tubular epithelial cells, undergo metabolic shifts toward aerobic glycolysis to amplify proinflammatory responses and fortify cellular resilience to septic stimuli. As the disease progresses, these cells revert to oxidative phosphorylation, thus promoting anti-inflammatory reactions and enhancing functional restoration. Alterations in mitochondrial dynamics and metabolic reprogramming are central to the energetic changes that occur during S-AKI. In this review, we summarize the current understanding of the pathogenesis of metabolic reprogramming in S-AKI, with a focus on each cell type involved. By identifying relevant key regulatory factors, we also explored potential metabolic reprogramming-related therapeutic targets for the management of S-AKI.

Understanding pulmonary hypertension: the need for an integrative metabolomics and transcriptomics approach

Pulmonary hypertension (PH), characterised by mean pulmonary arterial pressure (mPAP) >20 mm Hg at rest, is a complex pathophysiological disorder associated with multiple clinical conditions. The high prevalence of the disease along with increased mortality and morbidity makes it a global health burden. Despite major advances in understanding the disease pathophysiology, much of the underlying complex molecular mechanism remains to be elucidated. Lack of a robust diagnostic test and specific therapeutic targets also poses major challenges. This review provides a comprehensive update on the dysregulated pathways and promising candidate markers identified in PH patients using the transcriptomics and metabolomics approach. The review also highlights the need of using an integrative multi-omics approach for obtaining insight into the disease at a molecular level. The integrative multi-omics/pan-omics approach envisaged to help in bridging the gap from genotype to phenotype is outlined. Finally, the challenges commonly encountered while conducting omics-driven studies are also discussed.

PHD2 enzyme is an intracellular manganese sensor that initiates the homeostatic response against elevated manganese

Intracellular sensors detect changes in levels of essential metals to initiate homeostatic responses. But, a mammalian manganese (Mn) sensor is unknown, representing a major gap in understanding of Mn homeostasis. Using human-relevant models, we recently reported that: 1) the primary homeostatic response to elevated Mn is upregulation of hypoxia-inducible factors (HIFs), which increases expression of the Mn efflux transporter SLC30A10; and 2) elevated Mn blocks the prolyl hydroxylation of HIFs by prolyl hydroxylase domain (PHD) enzymes, which otherwise targets HIFs for degradation. Thus, the mammalian mechanism for sensing elevated Mn likely relates to PHD inhibition. Moreover, 1) Mn substitutes for a catalytic iron (Fe) in PHD structures; and 2) exchangeable cellular levels of Fe and Mn are comparable. Therefore, we hypothesized that elevated Mn directly inhibits PHD by replacing its catalytic Fe. In vitro assays using catalytically active PHD2, the primary PHD isoform, revealed that Mn inhibited, and Fe supplementation rescued, PHD2 activity. However, a mutation in PHD2 (D315E) that selectively reduced Mn binding without substantially impacting Fe binding or enzymatic activity resulted in complete insensitivity of PHD2 to Mn in vitro. Additionally, hepatic cells expressing full-length PHD2D315E were less sensitive to Mn-induced HIF activation and SLC30A10 upregulation than PHD2wild-type. These results: 1) define a fundamental Mn sensing mechanism for controlling Mn homeostasis-elevated Mn inhibits PHD2, which functions as a Mn sensor, by outcompeting its catalytic Fe, and PHD2 inhibition activates HIF signaling to up-regulate SLC30A10; and 2) identify a unique mode of metal sensing that may have wide applicability.

Dissecting the multifaceted roles of autophagy in cancer initiation, growth, and metastasis: from molecular mechanisms to therapeutic applications

Autophagy is a cytoplasmic defense mechanism that cells use to break and reprocess their intracellular components. This utilization of autophagy is regarded as a savior in nutrient-deficient and other stressful conditions. Hence, autophagy keeps contact with and responds to miscellaneous cellular tensions and diverse pathways of signal transductions, such as growth signaling and cellular death. Importantly, autophagy is regarded as an effective tumor suppressor because regular autophagic breakdown is essential for cellular maintenance and minimizing cellular damage. However, paradoxically, autophagy has also been observed to promote the events of malignancies. This review discussed the dual role of autophagy in cancer, emphasizing its influence on tumor survival and progression. Possessing such a dual contribution to the malignant establishment, the prevention of autophagy can potentially advocate for the advancement of malignant transformation. In contrast, for the context of the instituted tumor, the agents of preventing autophagy potently inhibit the advancement of the tumor. Key regulators, including calpain 1, mTORC1, and AMPK, modulate autophagy in response to nutritional conditions and stress. Oncogenic mutations like RAS and B-RAF underscore autophagy's pivotal role in cancer development. The review also delves into autophagy's context-dependent roles in tumorigenesis, metastasis, and the tumor microenvironment (TME). It also discusses the therapeutic effectiveness of autophagy for several cancers. The recent implication of autophagy in the control of both innate and antibody-mediated immune systems made it a center of attention to evaluating its role concerning tumor antigens and treatments of cancer.

Recent Advances in Molecular and Genetic Research on Uveal Melanoma

Uveal melanoma (UM), a distinct subtype of melanoma, presents unique challenges in its clinical management due to its complex molecular landscape and tendency for liver metastasis. This review highlights recent advancements in understanding the molecular pathogenesis, genetic alterations, and immune microenvironment of UM, with a focus on pivotal genes, such as GNAQ/11, BAP1, and CYSLTR2, and delves into the distinctive genetic and chromosomal classifications of UM, emphasizing the role of mutations and chromosomal rearrangements in disease progression and metastatic risk. Novel diagnostic biomarkers, including circulating tumor cells, DNA and extracellular vesicles, are discussed, offering potential non-invasive approaches for early detection and monitoring. It also explores emerging prognostic markers and their implications for patient stratification and personalized treatment strategies. Therapeutic approaches, including histone deacetylase inhibitors, MAPK pathway inhibitors, and emerging trends and concepts like CAR T-cell therapy, are evaluated for their efficacy in UM treatment. This review identifies challenges in UM research, such as the limited treatment options for metastatic UM and the need for improved prognostic tools, and suggests future directions, including the discovery of novel therapeutic targets, immunotherapeutic strategies, and advanced drug delivery systems. The review concludes by emphasizing the importance of continued research and innovation in addressing the unique challenges of UM to improve patient outcomes and develop more effective treatment strategies.

Hypoxia-Sonic Hedgehog Axis as a Driver of Primitive Hematopoiesis Development and Evolution in Cavefish

The teleost Astyanax mexicanus consists of surface dwelling (surface fish) and cave dwelling (cavefish) forms. Cavefish have evolved in subterranean habitats characterized by reduced oxygen levels (hypoxia) and show constructive and regressive phenotypic traits controlled by increased Sonic hedgehog (Shh) signaling along the embryonic midline. The enhancement of primitive hematopoietic domains, which are formed bilaterally in the anterior and posterior lateral plate mesoderm, are responsible for the development of more larval erythrocytes in cavefish relative to surface fish. In this study, we determine the role of hypoxia and Shh signaling in the development and evolution of primitive hematopoiesis in cavefish. We show that hypoxia treatment during embryogenesis increases primitive hematopoiesis and erythrocyte development in surface fish. We also demonstrate that upregulation of Shh midline signaling by treatment with the Smoothened agonist SAG increases primitive hematopoiesis and erythrocyte development in surface fish, whereas Shh downregulation via treatment with the Smoothened inhibitor cyclopamine decreases these traits in cavefish. Together these results suggest that hematopoietic enhancement is regulated by hypoxia and the Shh signaling system. Lastly, we demonstrate that hypoxia treatment enhances expression of Shh signaling along the midline of surface fish embryos. Thus, we conclude that a hypoxia-Shh axis may drive the adaptive evolution of primitive hematopoiesis and erythrocyte development in cavefish.

Highlights

Hypoxia increases hematopoiesis and erythrocytes in surface fishShh upregulation increases hematopoiesis and erythrocytes in surface fishShh inhibition decreases hematopoiesis and erythrocytes in cavefishHypoxia upregulates Shh along the embryonic midline in surface fish.

BMAL1-HIF2α heterodimers contribute to ccRCC

Circadian disruption enhances cancer risk, and many tumors exhibit disordered circadian gene expression. We show rhythmic gene expression is unexpectedly robust in clear cell renal cell carcinoma (ccRCC). Furthermore, the clock gene BMAL1 is higher in ccRCC than in healthy kidneys, unlike in other tumor types. BMAL1 is closely related to ARNT, and we show that BMAL1-HIF2α regulates a subset of HIF2α target genes in ccRCC cells. Depletion of BMAL1 reprograms HIF2α chromatin association and target gene expression and reduces ccRCC growth in culture and in xenografts. Analysis of pre-existing data reveals higher BMAL1 in patient-derived xenografts that are sensitive to growth suppression by a HIF2α antagonist (PT2399). We show that BMAL1-HIF2α is more sensitive than ARNT-HIF2α to suppression by PT2399, and increasing BMAL1 sensitizes 786O cells to growth inhibition by PT2399. Together, these findings indicate that an alternate HIF2α heterodimer containing the circadian partner BMAL1 contributes to HIF2α activity, growth, and sensitivity to HIF2α antagonist drugs in ccRCC cells.

Identification of Small Molecule Ligand Binding Sites On and In the ARNT PAS-B Domain

Transcription factors are generally challenging to target with small molecule inhibitors due to their structural plasticity and lack of catalytic sites. Notable exceptions include several naturally ligand-regulated transcription factors, including our prior work with the heterodimeric HIF-2 transcription factor which showed that small molecule binding within an internal pocket of the HIF-2α PAS-B domain can disrupt its interactions with its dimerization partner, ARNT. Here, we explore the feasibility of similarly targeting small molecules to the analogous ARNT PAS-B domain itself, potentially opening a promising route to simultaneously modulate several ARNT-mediated signaling pathways. Using solution NMR screening of an in-house fragment library, we previously identified several compounds that bind ARNT PAS-B and, in certain cases, antagonize ARNT association with the TACC3 transcriptional coactivator. However, these ligands have only modest binding affinities, complicating characterization of their binding sites. We address this challenge by combining NMR, MD simulations, and ensemble docking to identify ligand-binding 'hotspots' on and within the ARNT PAS-B domain. Our data indicate that the two ARNT/TACC3 inhibitors, KG-548 and KG-655, bind to a β-sheet surface implicated in both HIF-2 dimerization and coactivator recruitment. Furthermore, while KG-548 binds exclusively to the β-sheet surface, KG-655 can additionally bind within a water-accessible internal cavity in ARNT PAS-B. Finally, KG-279, while not a coactivator inhibitor, exemplifies ligands that preferentially bind only to the internal cavity. All three ligands promoted ARNT PAS-B homodimerization, albeit to varying degrees. Taken together, our findings provide a comprehensive overview of ARNT PAS-B ligand-binding sites and may guide the development of more potent coactivator inhibitors for cellular and functional studies.

Hif3α Plays Key Roles in the Progression of Alzheimer's Disease Caused by Circadian Rhythm Disruption through Regulating the m6A/KDM3A/TGF-β1 Axis

Disrupted circadian rhythms are associated with the onset of chronic diseases and impairments, including cancer, diabetes, and hypertension. However, whether circadian disruptions accelerate the progression of Alzheimer's disease and the respective pathway remains unclear. In this study, we constructed animal models using male C57BL/6N and APP/PS1 mice. Irregular illumination during sleeping hours was administered to the mice in our intervention groups to consistently disrupt their circadian rhythms. The impact of the intervention was evaluated through body weight tracking, cerebral index determination, histopathological staining, and biochemical marker analysis. Transcriptomic sequencing identified critical genes, with the data subsequently validated using RNA m6A detection and site analysis. The evaluations revealed that circadian disruptions impaired normal weight gain, liver and kidney functions, neuronal cells, and overall brain function. Transcriptomic sequencing data revealed a trend of elevating expression of Hif3α mRNA in the intervention groups. Further analysis of specific gene sites revealed that m6A methylation of the Hif3α gene at m6A site 3632 primarily drove the observed variations in HIF3A protein expression in our model. Furthermore, the expression of proteins in PC12 cells, N2a cells, and mice brains validated that an increase in HIF3A expression decreased KDM3A and TGF-β1 protein expression. Our study reveals a hitherto unknown pathway through which the disruption of circadian rhythms, by triggering m6A methylation at m6A site 3632 in the Hif3α gene, leads to the initiation and acceleration of AD. These findings provide valuable insights and guidelines for treating AD patients and enhancing caregiving by professionals.

Regulation of the HIF switch in human endothelial and cancer cells

Hypoxia-inducible factors (HIFs) are transcription factors that reprogram the transcriptome for cells to survive hypoxic insults and oxidative stress. They are important during embryonic development and reprogram the cells to utilize glycolysis when the oxygen levels are extremely low. This metabolic change facilitates normal cell survival as well as cancer cell survival. The key feature in survival is the transition between acute hypoxia and chronic hypoxia, and this is regulated by the transition between HIF-1 expression and HIF-2/HIF-3 expression. This transition is observed in many human cancers and endothelial cells and referred to as the HIF Switch. Here we discuss the mechanisms involved in the HIF Switch in human endothelial and cancer cells which include mRNA and protein levels of the alpha chains of the HIFs. A major continuing effort in this field is directed towards determining the differences between normal and tumor cell utilization of this important pathway, and how this could lead to potential therapeutic approaches.

Mild Hypoxia Accelerates Cerebral Cavernous Malformation Disease Through CX3CR1-CX3CL1 Signaling

BACKGROUND

Heterogeneity in the severity of cerebral cavernous malformations (CCMs) disease, including brain bleedings and thrombosis that cause neurological disabilities in patients, suggests that environmental, genetic, or biological factors act as disease modifiers. Still, the underlying mechanisms are not entirely understood. Here, we report that mild hypoxia accelerates CCM disease by promoting angiogenesis, neuroinflammation, and vascular thrombosis in the brains of CCM mouse models.

METHODS

We used genetic studies, RNA sequencing, spatial transcriptome, micro-computed tomography, fluorescence-activated cell sorting, multiplex immunofluorescence, coculture studies, and imaging techniques to reveal that sustained mild hypoxia via the CX3CR1-CX3CL1 (CX3C motif chemokine receptor 1/chemokine [CX3C motif] ligand 1) signaling pathway influences cell-specific neuroinflammatory interactions, contributing to heterogeneity in CCM severity.

RESULTS

Histological and expression profiles of CCM neurovascular lesions (Slco1c1-iCreERT2;Pdcd10fl/fl; Pdcd10BECKO) in male and female mice found that sustained mild hypoxia (12% O2, 7 days) accelerates CCM disease. Our findings indicate that a small reduction in oxygen levels can significantly increase angiogenesis, neuroinflammation, and thrombosis in CCM disease by enhancing the interactions between endothelium, astrocytes, and immune cells. Our study indicates that the interactions between CX3CR1 and CX3CL1 are crucial in the maturation of CCM lesions and propensity to CCM immunothrombosis. In particular, this pathway regulates the recruitment and activation of microglia and other immune cells in CCM lesions, which leads to lesion growth and thrombosis. We found that human CX3CR1 variants are linked to lower lesion burden in familial CCMs, proving it is a genetic modifier in human disease and a potential marker for aggressiveness. Moreover, monoclonal blocking antibody against CX3CL1 or reducing 1 copy of the Cx3cr1 gene significantly reduces hypoxia-induced CCM immunothrombosis.

CONCLUSIONS

Our study reveals that interactions between CX3CR1 and CX3CL1 can modify CCM neuropathology when lesions are accelerated by environmental hypoxia. Moreover, a hypoxic environment or hypoxia signaling caused by CCM disease influences the balance between neuroinflammation and neuroprotection mediated by CX3CR1-CX3CL1 signaling. These results establish CX3CR1 as a genetic marker for patient stratification and a potential predictor of CCM aggressiveness.

Modified Zhenwu Tang delays chronic renal failure progression by modulating oxidative stress and hypoxic responses in renal proximal tubular epithelial cells

Background

Tubulointerstitial fibrosis (TIF) is a critical pathological feature of chronic renal failure (CRF), with oxidative stress (OS) and hypoxic responses in renal proximal tubular epithelial cells playing pivotal roles in disease progression. This study explores the effects of Modified Zhenwu Tang (MZWT) on these processes, aiming to uncover its potential mechanisms in slowing CRF progression.

Methods

We used adenine (Ade) to induce CRF in rats, which were then treated with benazepril hydrochloride (Lotensin) and MZWT for 8 weeks. Assessments included liver and renal function, electrolytes, blood lipids, renal tissue pathology, OS levels, the hypoxia-inducible factor (HIF) pathway, inflammatory markers, and other relevant indicators. In vitro, human renal cortical proximal tubular epithelial cells were subjected to hypoxia and lipopolysaccharide for 72 h, with concurrent treatment using MZWT, FM19G11, and N-acetyl-l-cysteine. Measurements taken included reactive oxygen species (ROS), HIF pathway activity, inflammatory markers, and other relevant indicators.

Results

Ade treatment induced significant disruptions in renal function, blood lipids, electrolytes, and tubulointerstitial architecture, alongside heightened OS, HIF pathway activation, and inflammatory responses in rats. In vivo, MZWT effectively ameliorated proteinuria, renal dysfunction, lipid and electrolyte imbalances, and renal tissue damage; it also suppressed OS, HIF pathway activation, epithelial-mesenchymal transition (EMT) in proximal tubular epithelial cells, and reduced the production of inflammatory cytokines and collagen fibers. In vitro findings demonstrated that MZWT decreased apoptosis, reduced ROS production, curbed OS, HIF pathway activation, and EMT in proximal tubular epithelial cells, and diminished the output of inflammatory cytokines and collagen.

Conclusion

OS and hypoxic responses significantly contribute to TIF development. MZWT mitigates these responses in renal proximal tubular epithelial cells, thereby delaying the progression of CRF.

HIF2α-dependent Dock4/Rac1-signaling regulates formation of adherens junctions and cell polarity in normoxia

Hypoxia-inducible factors (HIF) 1 and 2 regulate similar but distinct sets of target genes. Although HIFs are best known for their roles in mediating the hypoxia response accumulating evidence suggests that under certain conditions HIFs, particularly HIF2, may function also under normoxic conditions. Here we report that HIF2α functions under normoxic conditions in kidney epithelial cells to regulate formation of adherens junctions. HIF2α expression was required to induce Dock4/Rac1/Pak1-signaling mediating stability and compaction of E-cadherin at nascent adherens junctions. Impaired adherens junction formation in HIF2α- or Dock4-deficient cells led to aberrant cyst morphogenesis in 3D kidney epithelial cell cultures. Taken together, we show that HIF2α functions in normoxia to regulate epithelial morphogenesis.

CD5L as a promising biological therapeutic for treating sepsis

Sepsis results from systemic, dysregulated inflammatory responses to infection, culminating in multiple organ failure. Here, we demonstrate the utility of CD5L for treating experimental sepsis caused by cecal ligation and puncture (CLP). We show that CD5L's important features include its ability to enhance neutrophil recruitment and activation by increasing circulating levels of CXCL1, and to promote neutrophil phagocytosis. CD5L-deficient mice exhibit impaired neutrophil recruitment and compromised bacterial control, rendering them susceptible to attenuated CLP. CD5L-/- peritoneal cells from mice subjected to medium-grade CLP exhibit a heightened pro-inflammatory transcriptional profile, reflecting a loss of control of the immune response to the infection. Intravenous administration of recombinant CD5L (rCD5L) in immunocompetent C57BL/6 wild-type (WT) mice significantly ameliorates measures of disease in the setting of high-grade CLP-induced sepsis. Furthermore, rCD5L lowers endotoxin and damage-associated molecular pattern (DAMP) levels, and protects WT mice from LPS-induced endotoxic shock. These findings warrant the investigation of rCD5L as a possible treatment for sepsis in humans.

Electro-Metabolic Coupling of Cumulus-Oocyte Complex

Oocyte-cumulus cell interaction is essential for oocyte maturation and competence. The bidirectional crosstalk network mediated by gap junctions is fundamental for the metabolic cooperation between these cells. As cumulus cells exhibit a more glycolytic phenotype, they can provide metabolic substrates that the oocyte can use to produce ATP via oxidative phosphorylation. The impairment of mitochondrial activity plays a crucial role in ovarian aging and, thus, in fertility, determining the success or failure of assisted reproductive techniques. This review aims to deepen the knowledge about the electro-metabolic coupling of the cumulus-oocyte complex and to hypothesize a putative role of potassium channel modulators in order to improve fertility, promote intracellular Ca2+ influx, and increase the mitochondrial biogenesis and resulting ATP levels in cumulus cells.

Thymic gene expression analysis reveals a potential link between HIF-1A and Th17/Treg imbalance in thymoma associated myasthenia gravis

Myasthenia gravis (MG) is an immune-mediated disease frequently associated with thymic changes. Increased T helper 17 (Th17) cell activity and dysfunctional regulatory T (Treg) cells have been demonstrated in subgroups of MG. On the other hand, hypoxia-inducible factor 1 (HIF-1) has been shown to regulate the Th17/Treg balance by inducing Th17 differentiation while attenuating Treg development. To identify the underlying mechanisms of different thymic pathologies in MG development, we evaluated thymic samples from thymoma-associated myasthenia gravis (TAMG), MG with hyperplasia (TFH-MG) and thymoma without MG (TOMA) patients. Differential gene expression analysis revealed that TAMG and TFH-MG cells are associated with different functional pathways. A higher RORC/FOXP3 ratio provided evidence for Th17/Treg imbalance in TAMG potentially related to increased HIF1A. The hypoxic microenvironment in thymoma may be a driver of TAMG by increasing HIF1A. These findings may lead to new therapeutic approaches targeting HIF1A in the development of TAMG.

Regulation of Cancer-Associated miRNAs Expression under Hypoxic Conditions

Solid tumors frequently experience hypoxia or low O2 levels. In these conditions, hypoxia-inducible factor 1 alpha (HIF-1α) is activated and acts as a transcription factor that regulates cancer cell adaptation to O2 and nutrient deprivation. HIF-1α controls gene expression associated with various signaling pathways that promote cancer cell proliferation and survival. MicroRNAs (miRNAs) are 22-nucleotide noncoding RNAs that play a role in various biological processes essential for cancer progression. This review presents an overview of how hypoxia regulates the expression of multiple miRNAs in the progression of cancer cells.

OTUB2 silencing promotes ovarian cancer via mitochondrial metabolic reprogramming and can be synthetically targeted by CA9 inhibition

Ovarian cancer is an aggressive gynecological tumor characterized by a high relapse rate and chemoresistance. Ovarian cancer exhibits the cancer hallmark of elevated glycolysis, yet effective strategies targeting cancer cell metabolic reprogramming to overcome therapeutic resistance in ovarian cancer remain elusive. Here, we revealed that epigenetic silencing of Otubain 2 (OTUB2) is a driving force for mitochondrial metabolic reprogramming in ovarian cancer, which promotes tumorigenesis and chemoresistance. Mechanistically, OTUB2 silencing destabilizes sorting nexin 29 pseudogene 2 (SNX29P2), which subsequently prevents hypoxia-inducible factor-1 alpha (HIF-1α) from von Hippel-Lindau tumor suppressor-mediated degradation. Elevated HIF-1α activates the transcription of carbonic anhydrase 9 (CA9) and drives ovarian cancer progression and chemoresistance by promoting glycolysis. Importantly, pharmacological inhibition of CA9 substantially suppressed tumor growth and synergized with carboplatin in the treatment of OTUB2-silenced ovarian cancer. Thus, our study highlights the pivotal role of OTUB2/SNX29P2 in suppressing ovarian cancer development and proposes that targeting CA9-mediated glycolysis is an encouraging strategy for the treatment of ovarian cancer.

Exposure to a Low-Oxygen Environment Causes Implantation Failure and Transcriptomic Shifts in Mouse Uteruses and Ovaries

Hypoxia is a condition in which tissues of the body do not receive sufficient amounts of oxygen supply. Numerous studies have elucidated the intricate roles of hypoxia and its involvement in both physiological and pathological conditions. This study aimed to clarify the impact of a forced low-oxygen environment in early pregnancy by exposing mice to low-oxygen conditions for 24-72 h after fertilization. The treatment resulted in the complete failure of blastocyst implantation, accompanied by vascular hyperpermeability in the uterus. A transcriptome analysis of the uterus revealed remarkable alterations in gene expression between control normoxic- and hypoxic-treatment groups. These alterations were characterized by the differentially expressed genes categorized into the immune responses and iron coordination. Furthermore, exposure to a low-oxygen environment caused apoptosis in the corpus luteum within the ovary and a reduction in progesterone secretion. Consequently, diminished plasma progesterone levels were considered to contribute to implantation failure in combination with the activation of the hypoxic pathway in the uterus. Additionally, previous studies have demonstrated the impact of hypoxic reactions on blastocyst development and the pre-implantation process in the endometrium. Our findings suggest that the corpus luteum exhibits elevated susceptibility to hypoxia, thereby elucidating a critical aspect of its physiological response.

Hypoxia-inducible PRMT2 addiction in glioblastomas

Hypoxia-inducible transcription factors (HIFs) are key transcription factors for cellular response to low oxygen levels. However, the specific mediators responsible for activating downstream transcription are not well characterized. We previously identified Protein Arginine methyltransferase 2 (PRMT2), a highly expressed methyltransferase in glioblastoma multiforme, as a transcription co-activator. And we established a connection between PRMT2-mediated histone H3R8 asymmetric methylation (H3R8me2a) and transcription activation. Here we find that PRMT2 is activated by HIF1α under hypoxic conditions. And we demonstrate that PRMT2 and its H3R8me2a activity are required for the transcription activation of a significant subset of hypoxia-induced genes. Consequently, the inactivation of PRMT2 suppresses hypoxia-induced glioblastoma cell migration, attenuates tumor progression, and enhances chemotherapeutic sensitivity in mouse xenograft models. In addition, our analysis of clinical glioma specimens reveals a correlation between PRMT2 protein levels, HIF1α abundance, and an unfavorable prognosis. Our study establishes HIF1α-induced PRMT2 as a critical modulator in the activation of hypoxia-related transcriptional programs, ultimately driving malignant progression.

The mechanisms of ferroptosis in the pathogenesis of kidney diseases

The pathological features of acute and chronic kidney diseases are closely associated with cell death in glomeruli and tubules. Ferroptosis is a form of programmed cell death characterized by iron overload-induced oxidative stress. Ferroptosis has recently gained increasing attention as a pathogenic mechanism of kidney damage. Specifically, the ferroptosis signaling pathway has been found to be involved in the pathological process of acute and chronic kidney injury, potentially contributing to the development of both acute and chronic kidney diseases. This paper aims to elucidate the underlying mechanisms of ferroptosis and its role in the pathogenesis of kidney disease, highlighting its significance and proposing novel directions for its treatment.

Drp1-mediated mitochondrial fission promotes pulmonary fibrosis progression through the regulation of lipid metabolic reprogramming by ROS/HIF-1α

OBJECTIVE

To confirm the mechanism of dynamic-related protein 1 (Drp1)-mediated mitochondrial fission through ROS/HIF-1α-mediated regulation of lipid metabolic reprogramming in the progression of pulmonary fibrosis (PF).

METHODS

A mouse model of PF was established by intratracheal instillation of bleomycin (BLM) (2.5 mg/kg). A PF cell model was constructed by stimulating MRC-5 cells with TGF-β (10 ng/mL). Pathological changes in the lung tissue and related protein levels were observed via tissue staining. The indicators related to lipid oxidation were detected by a kit, and lipid production was confirmed through oil red O staining. Inflammatory factors were detected by enzyme-linked immunosorbent assay (ELISA). RT-qPCR, Western blotting and immunofluorescence staining were used to detect the expression of genes and proteins related to the disease. We used CCK-8 and EdU staining to confirm cell proliferation, flow cytometry was used to confirm apoptosis and ROS levels, α-SMA expression was detected by immunofluorescence staining, and mitochondria were observed by MitoTracker staining.

RESULTS

The BLM induced lung tissue structure and alveolar wall thickening in mice. Mitochondrial fission was observed in MRC-5 cells induced by TGF-β, which led to increased cell proliferation; decreased apoptosis; increased expression of collagen, α-SMA and Drp1; and increased lipid oxidation and inflammation. Treatment with the Drp1 inhibitor mdivi-1 or transfection with si-Drp1 attenuated the induction of BLM and TGF-β. For lipid metabolism, lipid droplets were formed in BLM-induced lung tissue and in TGF-β-induced cells, fatty acid oxidation genes and lipogenesis-related genes were upregulated, ROS levels in cells were increased, and the expression of HIF-1α was upregulated. Mdivi-1 treatment reversed TGF-β induction, while H2O2 treatment or OE-HIF-1α transfection reversed the effect of mdivi-1.

CONCLUSION

In PF, inhibition of Drp1 can prevent mitochondrial fission in fibroblasts and regulate lipid metabolism reprogramming through ROS/HIF-1α; thus, fibroblast activation was inhibited, alleviating the progression of PF.

HIF-1α regulates DcR3 to promote the development of endometriosis

OBJECTIVE

The aim of this study was to investigate the expression and clinical significance of HIF-1α and DcR3 in endometriosis by analysing clinical case data. Tissue samples were collected for tissue chip analysis and staining, and human endometrial stromal cells were isolated and cultured for cell experiments. Additionally, experiments were conducted on collected peritoneal fluid to explore the association and role of HIF-1α and DcR3 in endometriosis.

STUDY DESIGN

Patients who visited the Department of Obstetrics and Gynaecology at Central Hospital in Fengxian District, Shanghai, from January 2018 to December 2021 were recruited for this controlled study. Clinical data and tissue chip staining results were collected for multiple regression analysis on the clinical significance of HIF-1α and DcR3. Endometrial tissue, ovarian cysts, and pelvic fluid were collected, and human endometrial stromal cells were cultured. The impact of HIF-1α on DcR3 in different oxygen environments and its role in endometriosis were investigated through PCR, Western blotting, enzyme-linked immunosorbent assay, as well as adhesion and migration assays.

RESULTS

In patients with endometriosis, the expression of DcR3 and HIF-1α was found to be upregulated and correlated in ectopic endometrium. The expression of DcR3 served as an indicator of the severity of endometriosis. Hypoxia induced the expression of DcR3, which was regulated by HIF-1α and promoted migration and adhesion.

CONCLUSION

DcR3 can be used as a clinical indicator to assess the severity of endometriosis. The hypoxic environment in endometriosis enhances disease progression by regulating DcR3 through HIF-1α.

Alterations in the immune landscape characterized by inflammatory activation and immune escape within 12 h after trauma

BACKGROUND

Trauma is statistically a significant cause of mortality among patients across countries. Nevertheless, the precise correlation between genetic diagnostic markers and the intricate mechanism of trauma remains indistinct.

METHODS

Our study exclusively centered on trauma patients and selected three trauma-related datasets from the Gene Expression Omnibus (GEO) database, all of which had blood samples collected within post-traumatic 12 h. Differential gene screening, the WGCNA and Cytoscape software were employed to analyze the two datasets, with a particular emphasis on the top 100 genes selected based on MCC algorithm scores. A logistic diagnostic model was constructed by analyzing the intersection genes in the third dataset, leading to the identification of diagnostic biomarkers with high efficiency. The global immune landscape of these patients was extensively investigated using a multidimensional approach. Meanwhile, the underlying pathological and physiological mechanisms associated with early trauma status are summarized by integrating existing literature.

RESULTS

Out of these two GEO datasets, 21 overlapping genes were identified and incorporated into in the logistic diagnostic model constructed in the GSE36809 dataset. A panel of 9 genes was uncovered as a diagnostic biomarker, and their expression and correlation were subsequently verified. Additionally, by virtue of various algorithms, the findings revealed an upregulation of neutrophil expression and a downregulation of CD8+ T cell expression, indicating characteristic early trauma-induced inflammation activation and immune suppression. The correlation observed between the feature genes and immune cells serves to validate the exceptional diagnostic capability of these 9 genes in identifying trauma status and their promising potential for patients who could benefit from targeted immune interventions. Drawing from these findings, the discussion section offers insights into the underlying pathological and physiological mechanisms at play.

CONCLUSION

Our research has discovered a novel diagnostic biomarker and unveiled its association with post-traumatic immune alterations. This breakthrough enables accurate and timely diagnosis of early trauma, facilitating the implementation of appropriate healthcare interventions.

Lactate-driven type I collagen deposition facilitates cancer stem cell-like phenotype of head and neck squamous cell carcinoma

Lactate is known to play a crucial role in the progression of malignancies. However, its mechanism in regulating the malignant phenotype of head and neck squamous cell carcinoma (HNSCC) remains unclear. This study found that lactate increases cancer stem cell (CSC) characteristics of HNSCC by influencing the deposition of type I collagen (Col I). Lactate promotes Col I deposition through two distinct pathways. One is to convert lactate to pyruvate, a substrate for Col I hydroxylation. The other is the activation of HIF1-α and P4HA1, the latter being a rate-limiting enzyme for Col I synthesis. Inhibition of these two pathways effectively counteracts lactate-induced enhanced cell stemness. Further studies revealed that Col I affects CSC properties by regulating cell cycle dynamics. In conclusion, our research proposes that lactate-driven Col I deposition is essential for the acquisition of CSC properties, and lactate-centric Col I deposition may be an effective target for CSCs.

Three-Dimensional Cultivation a Valuable Tool for Modelling Canine Mammary Gland Tumour Behaviour In Vitro

Cell cultivation has been one of the most popular methods in research for decades. Currently, scientists routinely use two-dimensional (2D) and three-dimensional (3D) cell cultures of commercially available cell lines and primary cultures to study cellular behaviour, responses to stimuli, and interactions with their environment in a controlled laboratory setting. In recent years, 3D cultivation has gained more attention in modern biomedical research, mainly due to its numerous advantages compared to 2D cultures. One of the main goals where 3D culture models are used is the investigation of tumour diseases, in both animals and humans. The ability to simulate the tumour microenvironment and design 3D masses allows us to monitor all the processes that take place in tumour tissue created not only from cell lines but directly from the patient's tumour cells. One of the tumour types for which 3D culture methods are often used in research is the canine mammary gland tumour (CMT). The clinically similar profile of the CMT and breast tumours in humans makes the CMT a suitable model for studying the issue not only in animals but also in women.

Hypoxia-associated markers in the prognosis of oral canine melanoma

Canine oral malignant melanoma (COMM) is the most common neoplasm in the oral cavity characterized by local invasiveness and high metastatic potential. Hypoxia represents a crucial feature of the solid tumor microenvironment promoting cancer progression and drug resistance. Hypoxia-inducible factor-1α (HIF-1α) and its downstream effectors, vascular endothelial growth factor A (VEGF-A), glucose transporter isoform 1 (GLUT1), C-X-C chemokine receptor type 4 (CXCR4), and carbonic anhydrase IX (CAIX), are the main regulators of the adaptive response to low oxygen availability. The prognostic value of these markers was evaluated in 36 COMMs using immunohistochemistry. In addition, the effects of cobalt chloride-mediated hypoxia were evaluated in 1 primary COMM cell line. HIF-1α expression was observed in the nucleus, and this localization correlated with the presence or enhanced expression of HIF-1α-regulated genes at the protein level. Multivariate analysis revealed that in dogs given chondroitin sulfate proteoglycan-4 (CSPG4) DNA vaccine, COMMs expressing HIF-1α, VEGF-A, and CXCR4 were associated with shorter disease-free intervals (DFI) compared with tumors that were negative for these markers (P = .03), suggesting hypoxia can influence immunotherapy response. Western blotting showed that, under chemically induced hypoxia, COMM cells accumulate HIF-1α and smaller amounts of CAIX. HIF-1α induction and stabilization triggered by hypoxia was corroborated by immunofluorescence, showing its nuclear translocation. These findings reinforce the role of an hypoxic microenvironment in tumor progression and patient outcome in COMM, as previously established in several human and canine cancers. In addition, hypoxic markers may represent promising prognostic markers, highlighting opportunities for their use in therapeutic strategies for COMMs.

Bacteria-driven nanosonosensitizer delivery system for enhanced breast cancer treatment through sonodynamic therapy-induced immunogenic cell death

BACKGROUND

Sonodynamic therapy (SDT) has shown promise as a non-invasive cancer treatment due to its local effects and excellent tissue penetration. However, the limited accumulation of sonosensitizers at the tumor site hinders its therapeutic efficacy. Although nanosonosensitizers have improved local tumor accumulation through passive targeting via the enhanced permeability and retention effect (EPR), achieving sufficient accumulation and penetration into tumors remains challenging due to tumor heterogeneity and inaccurate targeting. Bacteria have become a promising biological carrier due to their unique characteristic of active targeting and deeper penetration into the tumor.

METHODS

In this study, we developed nanosonosensitizers consisting of sonosensitizer, hematoporphyrin monomethyl ether (HMME), and perfluoro-n-pentane (PFP) loaded poly (lactic-co-glycolic) acid (PLGA) nanodroplets (HPNDs). These HPNDs were covalently conjugated onto the surface of Escherichia coli Nissle 1917 (EcN) using carbodiimine chemistry. EcN acted as an active targeting micromotor for efficient transportation of the nanosonosensitizers to the tumor site in triple-negative breast cancer (TNBC) treatment. Under ultrasound cavitation, the HPNDs were disrupted, releasing HMME and facilitating its uptakes by cancer cells. This process induced reactive oxygen species (ROS)-mediated cell apoptosis and immunogenic cell death (ICD) in vitro and in vivo.

RESULTS

Our bacteria-driven nanosonosensitizer delivery system (HPNDs@EcN) achieved superior tumor localization of HMME in vivo compared to the group treated with only nanosonosensitizers. This enhanced local accumulation further improved the therapeutic effect of SDT induced-ICD therapeutic effect and inhibited tumor metastasis under ultrasound stimulation.

CONCLUSIONS

Our research demonstrates the potential of this ultrasound-responsive bacteria-driven nanosonosensitizer delivery system for SDT in TNBC. The combination of targeted delivery using bacteria and nanosonosensitizer-based therapy holds promise for achieving improved treatment outcomes by enhancing local tumor accumulation and stimulating ICD.

Sorafenib inhibits ossification of the posterior longitudinal ligament by blocking LOXL2-mediated vascularization

Ossification of the Posterior Longitudinal Ligament (OPLL) is a degenerative hyperostosis disease characterized by the transformation of the soft and elastic vertebral ligament into bone, resulting in limited spinal mobility and nerve compression. Employing both bulk and single-cell RNA sequencing, we elucidate the molecular characteristics, cellular components, and their evolution during the OPLL process at a single-cell resolution, and validate these findings in clinical samples. This study also uncovers the capability of ligament stem cells to exhibit endothelial cell-like phenotypes in vitro and in vivo. Notably, our study identifies LOXL2 as a key regulator in this process. Through gain-and loss-of-function studies, we elucidate the role of LOXL2 in the endothelial-like differentiation of ligament cells. It acts via the HIF1A pathway, promoting the secretion of downstream VEGFA and PDGF-BB. This function is not related to the enzymatic activity of LOXL2. Furthermore, we identify sorafenib, a broad-spectrum tyrosine kinase inhibitor, as an effective suppressor of LOXL2-mediated vascular morphogenesis. By disrupting the coupling between vascularization and osteogenesis, sorafenib demonstrates significant inhibition of OPLL progression in both BMP-induced and enpp1 deficiency-induced animal models while having no discernible effect on normal bone mass. These findings underscore the potential of sorafenib as a therapeutic intervention for OPLL.

pH-responsive CuS/DSF/EL/PVP nanoplatform alleviates inflammatory bowel disease in mice via regulating gut immunity and microbiota

The clinical treatment of inflammatory bowel disease (IBD) is challenging. We developed copper sulfate (CuS)/disulfiram (DSF)/methacrylic acid-ethyl acrylate copolymer (EL)/polyvinylpyrrolidone (PVP) nanoplatform (CuS/DSF/EL/PVP) and evaluated its efficiency for treating IBD. After oral administration, the pH-sensitive EL protected the CuS/DSF/EL/PVP against degradation by acidic gastric juices. Once the colon was reached, EL was dissolved, releasing DSF and Cu2+. Further, the main in vivo metabolite of DSF can bind to Cu2+ and form copper (II) N, N-diethyldithiocarbamate (CuET), which significantly alleviated acute colitis in mice. Notably, CuS/DSF/EL/PVP outperformed CuS/EL/PVP and DSF/EL/PVP nanoplatforms in reducing colonic pathology and improving the secretion of inflammation-related cytokines (such as IL-4 and IL-10) in the colonic mucosa. RNA-seq analysis revealed that the nanoplatform reduced colonic inflammation and promoted intestinal mucosal repair by upregulating C-type lectin receptor (CLR)-related genes and signaling pathways. Furthermore, CuS/DSF/EL/PVP showed potential for improving colitis Th1/Th17 cells through innate immunity stimulation, down-regulation of inflammatory cytokines, and upregulation of anti-inflammatory cytokines. Additionally, the intervention with CuS/DSF/EL/PVP led to increased intestinal flora diversity, decreased Escherichia-Shigella abundance, and elevated levels of short-chain fatty acid (SCFA)-producing bacteria Prevotella, Lactobacillus, and Bifidobacterium, indicating their potential to modulate the dysregulated intestinal flora and suppress inflammation. STATEMENT OF SIGNIFICANCE: Our study introduces the CuS/DSF/EL/PVP nanoplatform as a therapeutic strategy for treating inflammatory bowel disease (IBD). This approach demonstrates significant efficacy in targeting the colon and alleviating acute colitis in mice. It uniquely modulates gut immunity and microbiota, exhibiting a notable impact on inflammation-related cytokines and promoting intestinal mucosal repair. The nanoplatform's ability to regulate gut flora diversity, combined with its cost-effective and scalable production, positions it as a potentially transformative treatment for IBD, offering new avenues for personalized medical interventions.

Hypobaric hypoxia modulated structural characteristics of circulating cell-free DNA in high-altitude pulmonary edema

The utility of cell-free (cf) DNA has extended as a surrogate or clinical biomarker for various diseases. However, a more profound and expanded understanding of the diverse cfDNA population and its correlation with physiological phenotypes and environmental factors is imperative for using its full potential. The high-altitude (HA; altitude > 2,500 m above sea level) environment characterized by hypobaric hypoxia offers an observational case-control design to study the differential cfDNA profile in patients with high-altitude pulmonary edema (HAPE) (number of subjects, n = 112) and healthy HA sojourners (n = 111). The present study investigated cfDNA characteristics such as concentration, fragment length size, degree of integrity, and subfractions reflecting mitochondrial-cfDNA copies in the two groups. The total cfDNA level was significantly higher in patients with HAPE, and the level increased with increasing HAPE severity (P = 0.0036). A lower degree of cfDNA integrity of 0.346 in patients with HAPE (P = 0.001) indicated the prevalence of shorter cfDNA fragments in circulation in patients compared with the healthy HA sojourners. A significant correlation of cfDNA characteristics with the peripheral oxygen saturation levels in the patient group demonstrated the translational relevance of cfDNA molecules. The correlation was further supported by multivariate logistic regression and receiver operating characteristic curve. To our knowledge, our study is the first to highlight the association of higher cfDNA concentration, a lower degree of cfDNA integrity, and increased mitochondrial-derived cfDNA population with HAPE disease severity. Further deep profiling of cfDNA fragments, which preserves cell-type specific genetic and epigenetic features, can provide dynamic physiological responses to hypoxia.NEW & NOTEWORTHY This study observed altered cell-free (cf) DNA fragment patterns in patients with high-altitude pulmonary edema and the significant correlation of these patterns with peripheral oxygen saturation levels. This suggests deep profiling of cfDNA fragments in the future may identify genetic and epigenetic mechanisms underlying physiological and pathophysiological responses to hypoxia.

Isoquinoline-based intrinsic fluorescence assessment of erythropoiesis-stimulating agent, Roxadustat (FG-4592), in tablets: applications to content uniformity and human plasma evaluation

In the present study, a first validated and green spectrofluorimetric approach for its assessment and evaluation in different matrices was investigated. After using an excitation wavelength of 345 nm, Roxadustat (ROX) demonstrates a highly native fluorescence at an emission of 410 nm. The influences of experimental factors such as pH, diluting solvents, and different organized media were tested, and the most appropriate solvent choice was ethanol. It was confirmed that there was a linear relationship between the concentration of ROX and the relative fluorescence intensity in the range 60.0-1000.0 ng ml-1, with the limit of detection and limit of quantitation, respectively, being 17.0 and 53.0 ng ml-1. The mean recoveries % [±standard deviation (SD), n = 5] for pharmaceutical preparations were 100.11% ± 2.24%, whereas for plasma samples, they were 100.08 ± 1.08% (±SD, n = 5). The results obtained after the application of four greenness criteria, Analytical Eco-Scale metric, NEMI, GAPI, and AGREE metric, confirmed its eco-friendliness. In addition, the whiteness meter (RGB12) confirmed its level of sustainability. The International Council for Harmonisation (ICH) criteria were used to verify the developed method through the study in both spiked plasma samples and content uniformity evaluation. An appropriate standard for various applications in industry and quality control laboratories was developed.

SRT1720 inhibits bladder cancer cell progression by impairing autophagic flux

Bladder cancer (BC) is the most common cancer of the urinary tract, with poor survival, high recurrence rates, and lacking of targeted drugs. In this study, we constructed a library to screen compounds inhibiting bladder cancer cells growth. Among them, SRT1720 was identified to inhibit bladder cancer cell proliferation in vitro and in vivo. SRT1720 treatment also suppressed bladder cancer cells migration, invasion and induced apoptosis. Mechanism studies shown that SRT1720 promoted autophagosomes accumulation by inducing early-stage autophagy but disturbed the late-stage of autophagy by blocking fusion of autophagosomes and lysosomes. SRT1720 appears to induce autophagy related proteins expression and alter autophagy-related proteins acetylation to impede the autophagy flux. LAMP2, an important lysosomal associated membrane protein, may mediate SRT1720-inhibited autophagy flux as SRT1720 treatment significantly deacetylated LAMP2 which may influence its activity. Taken together, our results demonstrated that SRT1720 mediated apoptosis and autophagy flux inhibition may be a novel therapeutic strategy for bladder cancer treatment.

Treatment with the vascular endothelial growth factor-A antibody, bevacizumab, has sex-specific effects in a rat model of mild traumatic brain injury

Mild traumatic brain injury (mTBI) involves damage to the cerebrovascular system. Vascular endothelial growth factor-A (VEGF-A) is an important modulator of vascular health and VEGF-A promotes the brain's ability to recover after more severe forms of brain injury; however, the role of VEGF-A in mTBI remains poorly understood. Bevacizumab (BEV) is a monoclonal antibody that binds to VEGF-A and neutralises its actions. To better understand the role of VEGF-A in mTBI recovery, this study examined how BEV treatment affected outcomes in rats given a mTBI. Adult Sprague-Dawley rats were assigned to sham-injury + vehicle treatment (VEH), sham-injury + BEV treatment, mTBI + VEH treatment, mTBI + BEV treatment groups. Treatment was administered intracerebroventricularly via a cannula beginning at the time of injury and continuing until the end of the study. Rats underwent behavioral testing after injury and were euthanized on day 11. In both females and males, BEV had a negative impact on cognitive function. mTBI and BEV treatment increased the expression of inflammatory markers in females. In males, BEV treatment altered markers related to hypoxia and vascular health. These novel findings of sex-specific responses to BEV and mTBI provide important insights into the role of VEGF-A in mTBI.

Unveiling the impact of CDK8 on tumor progression: mechanisms and therapeutic strategies

CDK8 is an important member of the cyclin-dependent kinase family associated with transcription and acts as a key "molecular switch" in the Mediator complex. CDK8 regulates gene expression by phosphorylating transcription factors and can control the transcription process through Mediator complex. Previous studies confirmed that CDK8 is an important oncogenic factor, making it a potential tumor biomarker and a promising target for tumor therapy. However, CDK8 has also been confirmed to be a tumor suppressor, indicating that it not only promotes the development of tumors but may also be involved in tumor suppression. Therefore, the dual role of CDK8 in the process of tumor development is worth further exploration and summary. This comprehensive review delves into the intricate involvement of CDK8 in transcription-related processes, as well as its role in signaling pathways related to tumorigenesis, with a focus on its critical part in driving cancer progression.

Unraveling the role of HIF-1α in sepsis: from pathophysiology to potential therapeutics-a narrative review

Sepsis is characterized by organ dysfunction resulting from a dysregulated inflammatory response triggered by infection, involving multifactorial and intricate molecular mechanisms. Hypoxia-inducible factor-1α (HIF-1α), a notable transcription factor, assumes a pivotal role in the onset and progression of sepsis. This review aims to furnish a comprehensive overview of HIF-1α's mechanism of action in sepsis, scrutinizing its involvement in inflammatory regulation, hypoxia adaptation, immune response, and organ dysfunction. The review encompasses an analysis of the structural features, regulatory activation, and downstream signaling pathways of HIF-1α, alongside its mechanism of action in the pathophysiological processes of sepsis. Furthermore, it will delve into the roles of HIF-1α in modulating the inflammatory response, including its association with inflammatory mediators, immune cell activation, and vasodilation. Additionally, attention will be directed toward the regulatory function of HIF-1α in hypoxic environments and its linkage with intracellular signaling, oxidative stress, and mitochondrial damage. Finally, the potential therapeutic value of HIF-1α as a targeted therapy and its significance in the clinical management of sepsis will be discussed, aiming to serve as a significant reference for an in-depth understanding of sepsis pathogenesis and potential therapeutic targets, as well as to establish a theoretical foundation for clinical applications.

Hypoxia-Inducible Factor-1α Regulates High Phosphate-Induced Vascular Calcification via Type III Sodium-Dependent Phosphate Cotransporter 1

Vascular calcification (VC) has a high incidence in patients with chronic kidney disease, which is a worldwide public health problem and presents a heavy burden to society. Hypoxia-inducible factor (HIF)-1α, the active subunit of HIF-1, has been reported to play a vital role in high phosphate-induced VC. However, the underlying mechanism is still undetermined, and effective treatment is unavailable. In the present study, human aortic smooth muscle cells (HASMCs) were cultured under normal or high phosphate media conditions. HIF-1α small interfering RNA and overexpression plasmids were employed to regulate HIF-1α expression. Phosphonoformic acid was employed to restrain the function of type III sodium-dependent phosphate cotransporter 1 (Pit-1). The expression levels of HIF-1α, Pit-1, runt-related transcription factor 2 (Runx2), and smooth muscle 22 alpha (SM22α) were evaluated, and the calcium contents were also examined. Cell growth was assessed using an MTT assay. High phosphate stimulation caused an upregulation in HIF-1α and Pit-1 expression levels and induced calcium depositions in HASMCs. Upregulation of Runx2 expression accompanied by downregulation of SM22α expression was observed in the high phosphate group. Following the suppression of HIF-1α expression, there was a concomitant attenuation in Pit-1 expression, calcium deposition, the alteration of phenotypic transition marker genes, and vice versa. The most serious calcium deposition was noted in HASMCs cultured under high phosphate conditions which were pretreated with a HIF-1α overexpression plasmid. However, when the biological functions of Pit-1 were restrained, the putative serious calcium deposition was not formed even in HASMCs transfected with a HIF-1α overexpression plasmid. The findings confirmed that HIF-1α regulated Pit-1 expression and exerted its pro-calcifying effect through Pit-1, which identified HIF-1α and Pit-1 as therapeutic targets for high phosphate-induced VC.

PDGFRβ + cell HIF2α is dispensable for white adipose tissue metabolic remodeling and hepatic lipid accumulation in obese mice

BACKGROUND

Obesity is associated with extensive white adipose tissue (WAT) expansion and remodeling. Healthy WAT expansion contributes to the maintenance of energy balance in the liver, thereby ameliorating obesity-related hepatic steatosis. Tissue-resident mesenchymal stromal cell populations, including PDGFRβ + perivascular cells, are increasingly recognized pivotal as determinants of the manner in which WAT expands. However, the full array of regulatory factors controlling WAT stromal cell functions remains to be fully elucidated. Hypoxia-inducible factors (HIFs) are critical regulators in WAT stromal cell populations such as adipocyte precursor cells (APCs). It is revealed that HIF1α activation within PDGFRβ + stromal cells results in the suppression of de novo adipogenesis and the promotion of a pro-fibrogenic cellular program in obese animals. However, the role of HIF2α in PDGFRβ + cells remains undetermined in vivo.

METHODS

New genetic models were employed in which HIF1α (encoded by the Hif1a gene) and HIF2α (encoded by the Epas1 gene) are selectively inactivated in PDGFRβ + cells in an inducible manner using tamoxifen (TAM). With these models, both in vitro and in vivo functional analysis of PDGFRβ + cells lacking HIF proteins were performed. Additionally, comprehensive metabolic phenotyping in diet-induced mouse models were performed to investigate the roles of PDGFRβ + cell HIF proteins in WAT remodeling, liver energy balance and systemic metabolism.

RESULTS

Unlike HIF1α inactivation, the new findings in this study suggest that inducible ablation of HIF2α in PDGFRβ + cells does not cause apparent effects on WAT expansion induced by obesogenic diet. The adipogenic ability of PDGFRβ + APCs is not significantly altered by genetic HIF2α ablation. Moreover, no difference of key parameters associated with healthy WAT remodeling such as improvements of WAT insulin sensitivity, reduction in metabolic inflammation, as well as changes in liver fat accumulation or systemic glucose metabolism, is detected in PDGFRβ + cell Epas1-deficient mice.

CONCLUSION

The new findings in this study support that, in contrast to HIF1α, PDGFRβ + cell HIF2α appears dispensable for WAT metabolic remodeling and the resulting effects on liver metabolic homeostasis in diet-induced obesity, underscoring the isoform-specific roles of HIFα proteins in the regulation of adipose tissue biology.

NAP-seq reveals multiple classes of structured noncoding RNAs with regulatory functions

Up to 80% of the human genome produces "dark matter" RNAs, most of which are noncapped RNAs (napRNAs) that frequently act as noncoding RNAs (ncRNAs) to modulate gene expression. Here, by developing a method, NAP-seq, to globally profile the full-length sequences of napRNAs with various terminal modifications at single-nucleotide resolution, we reveal diverse classes of structured ncRNAs. We discover stably expressed linear intron RNAs (sliRNAs), a class of snoRNA-intron RNAs (snotrons), a class of RNAs embedded in miRNA spacers (misRNAs) and thousands of previously uncharacterized structured napRNAs in humans and mice. These napRNAs undergo dynamic changes in response to various stimuli and differentiation stages. Importantly, we show that a structured napRNA regulates myoblast differentiation and a napRNA DINAP interacts with dyskerin pseudouridine synthase 1 (DKC1) to promote cell proliferation by maintaining DKC1 protein stability. Our approach establishes a paradigm for discovering various classes of ncRNAs with regulatory functions.

Cholesterol metabolism in tumor microenvironment: cancer hallmarks and therapeutic opportunities

Cholesterol is crucial for cell survival and growth, and dysregulation of cholesterol homeostasis has been linked to the development of cancer. The tumor microenvironment (TME) facilitates tumor cell survival and growth, and crosstalk between cholesterol metabolism and the TME contributes to tumorigenesis and tumor progression. Targeting cholesterol metabolism has demonstrated significant antitumor effects in preclinical and clinical studies. In this review, we discuss the regulatory mechanisms of cholesterol homeostasis and the impact of its dysregulation on the hallmarks of cancer. We also describe how cholesterol metabolism reprograms the TME across seven specialized microenvironments. Furthermore, we discuss the potential of targeting cholesterol metabolism as a therapeutic strategy for tumors. This approach not only exerts antitumor effects in monotherapy and combination therapy but also mitigates the adverse effects associated with conventional tumor therapy. Finally, we outline the unresolved questions and suggest potential avenues for future investigations on cholesterol metabolism in relation to cancer.

HIF signaling overactivation inhibits lateral line neuromast development through Wnt in zebrafish

The lateral line is critical for prey detection, predator avoidance, schooling, and rheotaxis behavior in fish. As similar to hair cells in the mammalian inner ear, the lateral line sensory organ called neuromasts is a popular model for hair cell regeneration. However, the mechanism of lateral line development has not been fully understood. In this study, we showed for the first time that hypoxia-inducible factor (HIF) signaling is involved in lateral line development in zebrafish. hif1ab and epas1b were highly expressed in neuromasts during lateral line development. Hypoxia response induced by a prolyl hydroxylase domain-containing proteins (PHD) inhibitor treatment or vhl gene knockout significantly reduced hair cells and support cells in neuromast during lateral line development. In addition, inhibition of Hif-1α or Epas1 could partially rescue hair cells in the larvae with increased HIF activity, respectively. Moreover, the support cell proliferation and the expression of Wnt target genes decreased in vhl mutants which suggests that Wnt signaling mediated the role of HIF signaling in lateral line development. Collectively, our results demonstrate that HIF signaling overactivation inhibits lateral line development in zebrafish and suggest that inhibition of HIF signaling might be a potential therapeutic method for hair cell death.

LncRNA LUCAT1 Promotes Glioblastoma Progression by Enhancing HIF1α Activity

BACKGROUND

Hypoxia is associated with poor prognosis in many cancers including glioblastoma (GBM). Glioma stem-like cells (GSCs) often reside in hypoxic regions and serve as reservoirs for disease progression. Long non-coding RNAs (lncRNAs) have been implicated in GBM. However, the lncRNAs that modulate GSC adaptations to hypoxia are poorly understood. Identification of these lncRNAs may provide new therapeutic strategies to target GSCs under hypoxia.

METHODS

lncRNAs induced by hypoxia in GSCs were identified by RNAseq. LUCAT1 expression was assessed by qPCR, RNAseq, Northern blot, single molecule FISH in GSCs, and interrogated in IvyGAP, TCGA, and CGGA databases. LUCAT1 was depleted by shRNA, CRISPR/Cas9, and CRISPR/Cas13d. RNAseq, Western blot, immunohistochemistry, co-IP, ChIP, ChIPseq, RNA immunoprecipitation, and proximity ligation assay were performed to investigate mechanisms of action of LUCAT1. GSC viability, limiting dilution assay, and tumorigenic potential in orthotopic GBM xenograft models were performed to assess the functional consequences of depleting LUCAT1.

RESULTS

A new isoform of Lucat1 is induced by HIF1α and NRF2 in GSCs under hypoxia. LUCAT1 is highly expressed in hypoxic regions in GBM. Mechanistically, LUCAT1 formed a complex with HIF1α and its co-activator CBP to regulate HIF1α target gene expression and GSC adaptation to hypoxia. Depletion of LUCAT1 impaired GSC self-renewal. Silencing LUCAT1 decreased tumor growth and prolonged mouse survival in GBM xenograft models.

CONCLUSIONS

A HIF1α-LUCAT1 axis forms a positive feedback loop to amplify HIF1α signaling in GSCs under hypoxia. LUCAT1 promotes GSC self-renewal and GBM tumor growth. LUCAT1 is a potential therapeutic target in GBM.

Selective degradation of PL2L60 by metabolic stresses‑induced autophagy suppresses multi‑cancer growth

It has been reported that PL2L60 proteins, a product of PIWIL2 gene which might be activated by an intragenic promoter, could mediate a common pathway specifically for tumorigenesis. In the present study, it was further identified by using western blot assay that the PL2L60 proteins could be degraded in cancer cells through a mechanism of selective autophagy in response to oxidative stress. The PL2L60 was downregulated in various types of cancer cells under the hypoxic condition independently of HIF‑1α, resulting in apoptosis of cancer cells. Inhibition of autophagy by small interfering RNA targeting of either Beclin‑1 (BECN1) or Atg5 resulted in restoration of PL2L60 expression in hypoxic cancer cell. The hypoxic degradation of PL2L60 was also blocked by the attenuation of the autophagosome membrane protein Atg8/microtubule‑associated protein 1 light chain 3 (LC3) or autophagy cargo protein p62 expression. Surprisingly, Immunofluorescence analysis demonstrated that LC3 could be directly bound to PL2L60 and was required for the transport of PL2L60 from the nucleus to the cytoplasm for lysosomal flux under basal or activated autophagy in cancer cells. Moreover, flow cytometric analysis displayed that knocking down of PL2L60 mRNA but not PIWIL2 mRNA effectively inhibited cancer cell proliferation and promoted apoptosis of cancer cells. The similar results were obtained from in vivo tumorigenic experiment, in which PL2L60 downregulation in necroptosis areas was confirmed by immunohistochemistry. These results suggested that various cancer could be suppressed by promoting autophagy. The present study revealed a key role of autophagic degradation of PL2L60 in hypoxia‑induced cancer cell death, which could be used as a novel therapeutic target of cancer.

Drivers of cancer metastasis - Arise early and remain present

Cancer and its metastases arise from mutations of genes, drivers that promote a tumor's growth. Analyses of driver events provide insights into cancer cell history and may lead to a better understanding of oncogenesis. We reviewed 27 metastatic research studies, including pan-cancer studies, individual cancer studies, and phylogenetic analyses, and summarized our current knowledge of metastatic drivers. All of the analyzed studies had a high level of consistency of driver mutations between primary tumors and metastasis, indicating that most drivers appear early in cancer progression and are maintained in metastatic cells. Additionally, we reviewed data from around 50,000 metastatic cancer patients and compiled a list of genes altered in metastatic lesions. We performed Gene Ontology analysis and confirmed that the most significantly enriched processes in metastatic lesions were the epigenetic regulation of gene expression, signal transduction, cell cycle, programmed cell death, DNA damage, hypoxia and EMT. In this review, we explore the most recent discoveries regarding genetic factors in the advancement of cancer, specifically those that drive metastasis.

Mitochondrial dysfunction affects hepatic immune and metabolic remodeling in patients with hepatitis B virus-related acute-on-chronic liver failure

BACKGROUND

Immune dysregulation and metabolic derangement have been recognized as key factors that contribute to the progression of hepatitis B virus (HBV)-related acute-on-chronic liver failure (ACLF). However, the mechanisms underlying immune and metabolic derangement in patients with advanced HBV-ACLF are unclear.

AIM

To identify the bioenergetic alterations in the liver of patients with HBV-ACLF causing hepatic immune dysregulation and metabolic disorders.

METHODS

Liver samples were collected from 16 healthy donors (HDs) and 17 advanced HBV-ACLF patients who were eligible for liver transplantation. The mitochondrial ultrastructure, metabolic characteristics, and immune microenvironment of the liver were assessed. More focus was given to organic acid metabolism as well as the function and subpopulations of macrophages in patients with HBV-ACLF.

RESULTS

Compared with HDs, there was extensive hepatocyte necrosis, immune cell infiltration, and ductular reaction in patients with ACLF. In patients, the liver suffered severe hypoxia, as evidenced by increased expression of hypoxia-inducible factor-1α. Swollen mitochondria and cristae were observed in the liver of patients. The number, length, width, and area of mitochondria were adaptively increased in hepatocytes. Targeted metabolomics analysis revealed that mitochondrial oxidative phosphorylation decreased, while anaerobic glycolysis was enhanced in patients with HBV-ACLF. These findings suggested that, to a greater extent, hepa-tocytes used the extra-mitochondrial glycolytic pathway as an energy source. Patients with HBV-ACLF had elevated levels of chemokine C-C motif ligand 2 in the liver homogenate, which stimulates peripheral monocyte infiltration into the liver. Characterization and functional analysis of macrophage subsets revealed that patients with ACLF had a high abundance of CD68+ HLA-DR+ macrophages and elevated levels of both interleukin-1β and transforming growth factor-β1 in their livers. The abundance of CD206+ CD163+ macrophages and expression of interleukin-10 decreased. The correlation analysis revealed that hepatic organic acid metabolites were closely associated with macrophage-derived cytokines/chemokines.

CONCLUSION

The results indicated that bioenergetic alteration driven by hypoxia and mitochondrial dysfunction affects hepatic immune and metabolic remodeling, leading to advanced HBV-ACLF. These findings highlight a new therapeutic target for improving the treatment of HBV-ACLF.

Prolyl hydroxylase domain inhibitor is an effective pre-hospital pharmaceutical intervention for trauma and hemorrhagic shock

Pre-hospital potentially preventable trauma related deaths are mainly due to hypoperfusion-induced tissue hypoxia leading to irreversible organ dysfunction at or near the point of injury or during transportation prior to receiving definitive therapy. The prolyl hydroxylase domain (PHD) is an oxygen sensor that regulates tissue adaptation to hypoxia by stabilizing hypoxia inducible factor (HIF). The benefit of PHD inhibitors (PHDi) in the treatment of anemia and lactatemia arises from HIF stabilization, which stimulates endogenous production of erythropoietin and activates lactate recycling through gluconeogenesis. The results of this study provide insight into the therapeutic roles of MK-8617, a pan-inhibitor of PHD-1, 2, and 3, in the mitigation of lactatemia in anesthetized rats with polytrauma and hemorrhagic shock. Additionally, in an anesthetized rat model of lethal decompensated hemorrhagic shock, acute administration of MK-8617 significantly improves one-hour survival and maintains survival at least until 4 h following limited resuscitation with whole blood (20% EBV) at one hour after hemorrhage. This study suggests that pharmaceutical interventions to inhibit prolyl hydroxylase activity can be used as a potential pre-hospital countermeasure for trauma and hemorrhage at or near the point of injury.

MicroRNA-18a regulates the Pyroptosis, Apoptosis, and Necroptosis (PANoptosis) of osteoblasts induced by tumor necrosis factor-α via hypoxia-inducible factor-1α

BACKGROUND

Tumor necrosis factor-α (TNF-α) is involved in inflammatory responses and promotes cell death and the inhibition of osteogenic differentiation. MicroRNA (miRNA) plays a crucial role in the infected bone diseases, however, the biological role of miRNAs in inflammation-induced impaired osteogenic differentiation remains unclear. This study aimed to explore the role of miRNA-18a-5p (miR-18a) in regulating PANoptosis and osteogenic differentiation in an inflammatory environment via hypoxia-inducible factor-1α (HIF1-α).

METHODS

The expression of miR-18a in MC3T3-E1 cells was analyzed using quantitative reverse transcription-polymerase chain reaction in an inflammatory environment induced by TNF-α. The expression of HIF1-α and NLRP3 in LV-miR-18a or sh-miR-18a cells was analyzed using western blotting. Fluorescence imaging for cell death, flow cytometry, and alkaline phosphatase activity analysis were used to analyze the role of miR-18a in TNF-α-induced PANoptosis and the inhibition of osteogenic differentiation. An animal model of infectious bone defect was established to validate the regulatory role of miR-18a in an inflammatory environment.

RESULTS

The expression of miRNA-18a in the MC3T3-E1 cell line was significantly lower under TNF-α stimulation than in the normal environment. miR-18a significantly inhibited the expression of HIF1-α and NLRP3, and inhibition of HIF1-α expression further inhibited NLRP3 expression. Furthermore, inhibition of miR-18a expression promoted the TNF-α-induced PANoptosis and inhibition of osteogenic differentiation, whereas miR-18a overexpression and the inhibition of both HIF1-α and NLRP3 reduced the effects of TNF-α. These findings are consistent with those of the animal experiments.

CONCLUSION

miRNA-18a negatively affects HIF1-α/NLRP3 expression, inhibits inflammation-induced PANoptosis, and impairs osteogenic differentiation. Thus, it is a potential therapeutic candidate for developing anti-inflammatory strategies for infected bone diseases.