HIF transcription factors, inflammation, and immunity

GBP2 Regulates Lipid Metabolism by Inhibiting the HIF-1 Pathway to Alleviate the Progression of Allergic Rhinitis

Allergic rhinitis (AR) is a prevalent allergic disorder instigated by a variety of allergenic stimuli. The study aims to elucidate the mechanistic underpinnings of Guanylate-binding protein 2 (GBP2) in modulating AR. Bioinformatics analysis was used to identify hub genes in AR, and GBP2 was identified. Mice were injected with ovalbumin (OVA) to create AR model. The pathological changes of the nasal mucosa were observed by hematoxylin-eosin staining. ELISA and western blot demonstrated that in OVA-induced AR mice, high IgE and IgG1 levels, inflammation (increased TNF-α, IL-5 and IFN-γ), oxidative stress (high ROS, low TAOC and GSH) and abnormal lipid metabolism (increased TC and LDL-C, decreased HLD-C) were observed. Mouse nasal mucosal epithelial cells (MNECs) were treated with TNF-α to simulate AR. Cell viability and apoptosis were evaluated by CCK-8 assay and flow cytometer, respectively. In vitro assay revealed that GBP2 inhibited total IgE, OVA-IgE and IgG1 levels and suppressed abnormal lipid metabolism, inflammation and oxidative stress to alleviate AR. Furthermore, HIF-1 pathway was screened as the downstream pathway of GBP2. GBP2 inhibited the HIF-1 pathway, and Fenbendazole-d3, the activator of HIF-1 pathway, weakened the inhibitory effects of GBP2 on apoptosis, inflammation, oxidative stress and abnormal lipid metabolism in vitro. In summary, GBP2 alleviated abnormal lipid metabolism, inflammation and oxidative stress by inhibiting the HIF-1 pathway, providing a direction for the treatment of AR.

Accurate Transcription Factor Activity Inference to Decipher Cell Identity from Single-Cell Transcriptomic Data with MetaTF

Cellular heterogeneity within cancer tissues determines cancer progression and treatment response. Single-cell RNA sequencing (scRNA-seq) has provided a powerful approach for investigating the cellular heterogeneity of both cancer cells and stroma cells in the tumor microenvironment. However, the common practice to characterize cell identity based on the similarity of their gene expression profiles may not really indicate distinct cellular populations with unique roles. Generally, the cell identity and function are orchestrated by the expression of given specific genes tightly regulated by transcription factors (TFs). Therefore, deciphering TF activity is essential for gaining a better understanding of the uniqueness and functionality of each cell type. Herein, metaTF, a computational framework designed to infer TF activity in scRNA-seq data, is introduced and existing methods are outperformed for estimating TF activity. It presents the improved effectiveness in characterizing cell identity during mouse hematopoietic stem cell development. Furthermore, metaTF provides a superior characterization of the functional identity of breast cancer epithelial cells, and identifies a novel subset of neural-regulated T cells within the tumor immune microenvironment, which potentially activates BCL6 in response to neural-related signals. Overall, metaTF enables robust TF activity analysis from scRNA-seq data, significantly enhancing the characterization of cell identity and function.

Zinc deficiency as possible link between immunosenescence and age-related diseases

As global life expectancy increases, research reveals a critical challenge in aging: the progressive deterioration of immune function, termed immunosenescence. This age-related immune decline is characterized by a complex dysregulation of immune responses, which leaves older adults increasingly vulnerable to infections, chronic inflammatory states, and various degenerative diseases. Without intervention, immunosenescence significantly contributes to morbidity and mortality among the elderly, intensifying healthcare burdens and diminishing quality of life on both individual and societal levels. This review explores the essential role of zinc, a trace element critical for immune health, in mitigating the impact of immunosenescence and slowing the cascade of immunological dysfunctions associated with aging. By modulating the activity of key immune cells and pathways, zinc supplementation emerges as a promising approach to strengthen immunity, reduce oxidative stress, and counteract "inflammaging," a state of chronic, low-grade inflammation that accelerates tissue damage and drives disease progression. Zinc's involvement in cellular defense and repair mechanisms across the immune system highlights its ability to enhance immune cell functionality, resilience, and adaptability, strengthening the body's resistance to infection and its ability to manage stressors that contribute to diseases of aging. Indeed, zinc has demonstrated potential to improve immune responses, decrease inflammation, and mitigate the risk of age-related conditions including diabetes, depression, cardiovascular disease, and vision loss. Given the prevalent barriers to adequate zinc intake among older adults, including dietary limitations, decreased absorption, and interactions with medications, this review underscores the urgent need to address zinc deficiency in aging populations. Recent findings on zinc's cellular and molecular effects on immune health present zinc supplementation as a practical, accessible intervention for supporting healthier aging and improving quality of life. By integrating zinc into targeted strategies, public health efforts may not only sustain immunity in the elderly but also extend healthy longevity, reduce healthcare costs, and potentially mitigate the incidence and impact of chronic diseases that strain healthcare systems worldwide.

Cancer-associated fibroblasts and metabolic reprogramming predict pathologic response to neoadjuvant PD-1 blockade in resected non-small cell lung cancer

PURPOSE

Immunotherapy has transformed the neoadjuvant treatment landscape for patients with resectable locally advanced non-small cell lung cancer (NSCLC). However, a population of patients cannot obtain major pathologic response (MPR) and thus benefit less from neoadjuvant immunotherapy, highlighting the need to uncover the underlying mechanisms driving resistance to immunotherapy.

METHODS

Two published single-cell RNA sequencing (scRNA-seq) datasets were used to analyze the subsets of cancer-associated fibroblasts (CAFs) and T cells and functional alterations after neoadjuvant immunotherapy. The stromal signature predicting ICI response was identified and validated using our local cohort with stage III NSCLC receiving neoadjuvant immunotherapy and other 4 public ICI transcriptomic cohorts.

RESULTS

Non-MPR tumors showed higher enrichment of CAFs and increased extracellular matrix deposition than MPR tumors, as suggested by bioinformatic analysis. Further, CAF-mediated immune suppression may involve reciprocal interactions with T cells in addition to a physical barrier mechanism. In contrast, MPR tumors demonstrated therapy-induced activation of memory CD8+ T cells into an effector phenotype. Additionally, neoadjuvant immunotherapy resulted in expansion of precursor exhausted T (Texp) cells, which were remodeled into an anti-tumor phenotype. Notably, we identified metabolic heterogeneity within distinct T cell clusters during immunotherapy. Methionine recycling emerged as a predictive factor for T-cell differentiation and a favorable pathological response. The stromal signature was associated with ICI response, and this association was validated in five independent ICI transcriptomic cohorts.

CONCLUSION

These discoveries underscore the distinct tumor microenvironments in MPR and non-MPR patients and may elucidate resistance mechanisms to immunotherapy in NSCLC.

Effect of passive hypoxia on body fat mass in older and young adults: A systematic review and meta-analysis

AIM

Research in recent years has shown some beneficial effects of exposure to hypoxia on human health. However, the beneficial effects of passive hypoxic exposure on weight management and body composition are less explored. This meta-analysis aimed to determine if passive hypoxic exposure, compared to normal oxygen levels, reduces body weight and body fat in both older and younger adults.

METHODS

A systematic search of PubMed, Web of Science, and the Cochrane Library databases following PRISMA guidelines (up to June 2024) was performed. This analysis included studies focusing on the effects of passive hypoxia on body weight, body fat mass and lean body mass. Studies with interventions lasting less than one-week, dietary restriction, supplementation, or physical exercise were excluded. Subgroup analysis was conducted to see if the effects of passive hypoxia varied between younger (18-49 years) and older adults (≥ 50 years). Nine studies with a total of 218 participants were included.

RESULTS

Passive hypoxic exposure induced greater reductions in body fat mass (SMD = -0.45 [-0.76, -0.14], I2 = 0 %, p = 0.004) and body weight (MD = -0.81 [-1.53, -0.08], I2 = 0 %, p = 0.03) compared with normoxia. Subgroup analysis showed that older adults had larger effects on body fat mass than young adults.

CONCLUSIONS

Moderate passive hypoxic conditioning could be a useful therapy of managing body weight and body fat mass without health potential risks, with a greater effect in the older than in the young adults.

Hypoxia-reduced YAP phosphorylation enhances expression of Mucin5AC in nasal epithelial cells of chronic rhinosinusitis with nasal polyps

BACKGROUND

Chronic rhinosinusitis with nasal polyps (CRSwNP) is an upper respiratory disease characterized by persistent inflammation of the nasal mucosa. However, the mechanism of abnormal Mucin5AC expression by CRSwNP epithelial cells is not fully understood.

OBJECTIVE

We investigated the potential role of yes-associated protein (YAP) underlying the mechanism of excessive epithelial Mucin5AC expression in CRSwNP in a hypoxic model.

METHODS

Tissue biopsies of CRSwNP (n = 60), chronic rhinosinusitis without nasal polyps (CRSsNP) (n = 9) and healthy controls (n = 30) were investigated together with a well-established hypoxic model of primary human nasal epithelial cells (hNECs). The expression levels of hypoxia inducible factor (HIF)-1α and YAP, and the effect of the signaling axis on mucus secretion in hNECs were analyzed.

RESULTS

We observed a significant elevated expression levels of YAP in patients with CRSwNP and CRSsNP compared to controls. In addition, HIF-1α expression of CRSwNP was higher than that of control group. Under hypoxic conditions, HIF-1α was found to regulate the upregulation of YAP in hNECs. Further investigations revealed that HIF-1α facilitated the activation and nuclear localization of active-YAP by reducing the phosphorylation of YAP. This mechanism appeared to be linked to HIF-1α-mediated inhibition of LATS 1 phosphorylation and subsequent YAP degradation. HIF-1α was shown to promote the expression of P63 and the levels of Mucin5AC in hNECs by enhancing YAP activation.

CONCLUSION

Our findings indicated that hypoxia enhances YAP activation by decreasing p-LATS 1 and YAP phosphorylation. This has the potential to impact on the proliferation of basal cells and the differentiation of goblet cells in CRSwNP, ultimately leading to a pathological condition characterized by excessive Mucin5AC expression.

HIF-1α-Induced GPR171 Expression Mediates CCL2 Secretion by Mast Cells to Promote Gastric Inflammation During Helicobacter pylori Infection

BACKGROUND

Helicobacter pylori (H. pylori) infection is one of the most important risk factors for chronic gastritis, gastric ulcers, and gastric cancer. Mast cells act as a crucial regulator in bacterial infection. The mechanisms underlying mast cell activation and their role in H. pylori infection remain poorly understood.

MATERIALS AND METHODS

In gastric mucosal tissue, the number of mast cells, G-protein-coupled receptor 171 (GPR171) and CCL2 expression were detected by immunohistochemistry (IHC) or immunofluorescence between H. pylori-negative and H. pylori-positive patients. Mast cells were co-cultured with H. pylori, and transcriptome sequencing, RT-qPCR, and Western blotting (WB) were performed to identify receptors involved in mast cell activation. WB, chromatin immunoprecipitation (ChIP), and dual-luciferase reporter assays were conducted to investigate the molecular mechanism by which HIF-1α regulates GPR171 expression. Lentiviral knockdown, ELISA, WB, and IHC were used to evaluate the role of GPR171 during H. pylori infection. An in vivo mouse model of H. pylori infection was employed to assess the effects of GPR171 blockade on CCL2 expression and gastric mucosal inflammation.

RESULTS

In the study, we found that mast cell numbers were greatly increased and correlated with the severity of inflammation in H. pylori-infected patients. We found a new receptor, GPR171, was upregulated and involved in mast cell activation upon H. pylori infection. Furthermore, H. pylori infection induced the expression of GPR171 by promoting the activation of hypoxia-inducible factor 1 alpha (HIF-1α), which directly bound to hypoxia response elements in the GPR171 promoter and regulated its transcriptional activity. Blockade or loss of GPR171 in mast cells partially inhibited CCL2 secretion via the ERK1/2 signaling pathway. In the human gastric mucosa, CCL2 derived from mast cells was associated with gastric inflammation during H. pylori infection. In vivo murine studies indicated that H. pylori infection significantly upregulated CCL2 expression, while GPR171 inhibition partially reduced CCL2 levels and alleviated gastric mucosal inflammation.

CONCLUSIONS

We provide a novel mechanism that H. pylori activates mast cells to promote gastric inflammation.

HIF-1α Pathway in COVID-19: A Scoping Review of Its Modulation and Related Treatments

The COVID-19 pandemic, driven by SARS-CoV-2, has led to a global health crisis, highlighting the virus's unique molecular mechanisms that distinguish it from other respiratory pathogens. It is known that the Hypoxia-Inducible Factor 1α (HIF-1α) activates a complex network of intracellular signaling pathways regulating cellular energy metabolism, angiogenesis, and cell survival, contributing to the wide range of clinical manifestations of COVID-19, including Post-Acute COVID-19 Syndrome (PACS). Emerging evidence suggests that dysregulation of HIF-1α is a key driver of systemic inflammation, silent hypoxia, and pathological tissue remodeling in both the acute and post-acute phases of the disease. This scoping review was conducted following PRISMA-ScR guidelines and registered in INPLASY. It involved a literature search in Scopus and PubMed, supplemented by manual reference screening, with study selection facilitated by Rayyan software. Our analysis clarifies the dual role of HIF-1α, which may either worsen inflammatory responses and viral persistence or support adaptive mechanisms that reduce cellular damage. The potential for targeting HIF-1α therapeutically in COVID-19 is complex, requiring further investigation to clarify its precise role and translational applications. This review deepens the molecular understanding of SARS-CoV-2-induced cellular and tissue dysfunction in hypoxia, offering insights for improving clinical management strategies and addressing long-term sequelae.

Prognostic role of inflammatory and tumor biomarkers in hilar cholangiocarcinoma patients receiving postoperative adjuvant therapy

Background

Hilar cholangiocarcinoma (HCCA) is an aggressive cancer with poor prognosis after surgery. The systemic immune-inflammation index (SII) has been proposed as a prognostic marker, but its relationship with other markers such as CA19-9 remains unclear. This study investigates the prognostic significance of SII and CA19-9 in HCCA patients receiving post-surgery adjuvant therapy.

Methods

A cohort of 145 HCCA patients who underwent surgery and adjuvant therapy was analyzed. Patients were categorized into High SII and Low SII groups based on an optimal cutoff value of 672.8, determined using ROC curve analysis. Further stratification was performed based on CA19-9 levels. The associations between SII, CA19-9, and survival outcomes, including overall survival (OS) and disease-free survival (DFS), were assessed using Kaplan-Meier survival analysis and Cox proportional hazards regression.

Results

Elevated SII was significantly associated with worse OS (p = 0.0027) and DFS (p = 0.0024). Notably, a significant difference in CA19-9 levels was observed between high and low SII groups (p = 0.013), with higher CA19-9 levels in the high SII group. However, no significant difference in CA19-9 was found between the low SII groups (p = 0.128). Patients with both high SII and high CA19-9 levels had the poorest survival outcomes, with significantly higher risks of mortality and disease recurrence (HR for OS = 2.29, 95% CI: 1.23-4.25; HR for DFS = 2.16, 95% CI: 1.17-3.99). Multivariate analysis identified high SII, high CA19-9, lymph node metastasis, and local organ metastasis as independent prognostic factors.

Conclusions

Elevated SII and CA19-9 are independent prognostic markers for HCCA patients after surgery. The combination of high SII and high CA19-9 identifies a subgroup with the poorest prognosis, suggesting the potential for these markers to guide postoperative treatment decisions.

Macrophage Polarization in Lung Diseases: From Mechanisms to Therapeutic Strategies

Macrophages are pivotal immune cells involved in maintaining immune homeostasis and defending against pathogens. They exhibit significant plasticity and heterogeneity, enabling polarization into pro-inflammatory M1 or anti-inflammatory M2 phenotypes in response to distinct microenvironmental cues. The process of macrophage polarization is tightly regulated by complex signaling pathways and transcriptional networks. This review explores the factors influencing macrophage polarization, the associated signaling pathways, and their roles in the pathogenesis of lung diseases, including fibrosis, cancer, and chronic inflammatory conditions. By summarizing recent advances, we aim to provide insights into the immunoregulatory functions of macrophages and their therapeutic potential. Based on our review, it is believed that targeting macrophage polarization emerges as a promising approach for developing effective treatments for lung diseases, balancing inflammation and repair while mitigating disease progression.

Guiqi Huoxue capsule alleviates cervical spondylosis in rats: Insights from 16S rRNA sequencing, lipidomics, and network pharmacology

ETHNOPHARMACOLOGICAL RELEVANCE

Cervical spondylosis (CS) is a common condition primarily caused by intervertebral disc degeneration (IVDD), adversely affecting quality of life. Traditional Chinese medicine believes that Qi deficiency and blood stasis are the main pathogenesis of CS. Guiqi Huoxue capsule (GQHX) has the effect of beneficial Qi tonifying kidneys and promoting blood circulation, which is mainly used in the clinical treatment of CS (Qi deficiency and blood stasis syndrome). However, the underlying mechanism of action has not been reported and clarified.

AIM OF THE STUDY

The aim of this study was to investigate the efficacy and underlying mechanisms of GQHX in CS rats.

MATERIALS AND METHODS

The CS rat model (Qi deficiency and blood stasis syndrome) was established by using IVDD and Ovariectomy (OVX) surgeries, along with qi deficiency and blood stasis modeling. The effects of GQHX on CS rats were evaluated by behavioral tests, blood indexes, H&E staining, and other means. Fatty acid profiles and gut microbiota were analyzed using lipidomics and 16S rRNA sequencing. The mechanism of action of GQHX was investigated by network pharmacology and western blotting.

RESULTS

GQHX reduced the symptoms of CS rats as confirmed by behavioral indicators, serum markers, and other measures of efficacy. Meanwhile, 16S rRNA sequencing and lipidomics results showed that GQHX regulated the abundance of Blautia and Muribaculaceae, influencing the production of various fatty acids (e.g. isobutyric, isovaleric, and linoleic acids). More importantly, network pharmacology and Western blot results suggested that GQHX could alleviate the clinical symptoms of CS by regulating the abnormal expression of AGE-RAGE, MAPK, and HIF-1 signaling pathways.

CONCLUSION

This study elucidated the role of GQHX in alleviating CS and highlighted the mechanisms involved, particularly the regulation of gut microbiota and lipid metabolism, as well as the AGE-RAGE, MAPK, and HIF-1 signaling pathways.

Perfluoropentane-based oxygen-loaded nanodroplets reduce microglial activation through metabolic reprogramming

JOURNAL/nrgr/04.03/01300535-202504000-00032/figure1/v/2024-07-06T104127Z/r/image-tiff Microglia, the primary immune cells within the brain, have gained recognition as a promising therapeutic target for managing neurodegenerative diseases within the central nervous system, including Parkinson's disease. Nanoscale perfluorocarbon droplets have been reported to not only possess a high oxygen-carrying capacity, but also exhibit remarkable anti-inflammatory properties. However, the role of perfluoropentane in microglia-mediated central inflammatory reactions remains poorly understood. In this study, we developed perfluoropentane-based oxygen-loaded nanodroplets (PFP-OLNDs) and found that pretreatment with these droplets suppressed the lipopolysaccharide-induced activation of M1-type microglia in vitro and in vivo, and suppressed microglial activation in a mouse model of Parkinson's disease. Microglial suppression led to a reduction in the inflammatory response, oxidative stress, and cell migration capacity in vitro. Consequently, the neurotoxic effects were mitigated, which alleviated neuronal degeneration. Additionally, ultrahigh-performance liquid chromatography-tandem mass spectrometry showed that the anti-inflammatory effects of PFP-OLNDs mainly resulted from the modulation of microglial metabolic reprogramming. We further showed that PFP-OLNDs regulated microglial metabolic reprogramming through the AKT-mTOR-HIF-1α pathway. Collectively, our findings suggest that the novel PFP-OLNDs constructed in this study alleviate microglia-mediated central inflammatory reactions through metabolic reprogramming.

Decoding microglial immunometabolism: a new frontier in Alzheimer's disease research

Alzheimer's disease (AD) involves a dynamic interaction between neuroinflammation and metabolic dysregulation, where microglia play a central role. These immune cells undergo metabolic reprogramming in response to AD-related pathology, with key genes such as TREM2, APOE, and HIF-1α orchestrating these processes. Microglial metabolism adapts to environmental stimuli, shifting between oxidative phosphorylation and glycolysis. Hexokinase-2 facilitates glycolytic flux, while AMPK acts as an energy sensor, coordinating lipid and glucose metabolism. TREM2 and APOE regulate microglial lipid homeostasis, influencing Aβ clearance and immune responses. LPL and ABCA7, both associated with AD risk, modulate lipid processing and cholesterol transport, linking lipid metabolism to neurodegeneration. PPARG further supports lipid metabolism by regulating microglial inflammatory responses. Amino acid metabolism also contributes to microglial function. Indoleamine 2,3-dioxygenase controls the kynurenine pathway, producing neurotoxic metabolites linked to AD pathology. Additionally, glucose-6-phosphate dehydrogenase regulates the pentose phosphate pathway, maintaining redox balance and immune activation. Dysregulated glucose and lipid metabolism, influenced by genetic variants such as APOE4, impair microglial responses and exacerbate AD progression. Recent findings highlight the interplay between metabolic regulators like REV-ERBα, which modulates lipid metabolism and inflammation, and Syk, which influences immune responses and Aβ clearance. These insights offer promising therapeutic targets, including strategies aimed at HIF-1α modulation, which could restore microglial function depending on disease stage. By integrating metabolic, immune, and genetic factors, this review underscores the importance of microglial immunometabolism in AD. Targeting key metabolic pathways could provide novel therapeutic strategies for mitigating neuroinflammation and restoring microglial function, ultimately paving the way for innovative treatments in neurodegenerative diseases.

The FKBPL-based therapeutic peptide, AD-01, protects the endothelium from hypoxia-induced damage by stabilising hypoxia inducible factor-α and inflammation

BACKGROUND

Endothelial dysfunction is a hallmark feature of cardiovascular disease (CVD), yet the underlying mechanisms are still poorly understood. This has impeded the development of effective therapies, particularly for peripheral artery disease. FK506-binding protein like (FKBPL) and its therapeutic peptide mimetic, AD-01, are crucial negative regulators of angiogenesis, however their roles in CVD are unknown. In this study, we aimed to elucidate the FKBPL-mediated mechanisms involved in regulating endothelial dysfunction induced by hypoxia or inflammation, and to determine whether AD-01 can effectively restore endothelial function under these conditions.

METHODS

Hindlimb ischemia was induced in mice by ligating the proximal and distal ends of the right femoral artery, and, after three days, the gastrocnemius muscle was collected for immunofluorescence staining, and RNA extraction. A 3D in vitro microfluidics model was developed to determine the endothelial cell migration and impact of FKBPL following treatments with: (i) 24 µM FKBPL targeted siRNA, (ii) 1 mM hypoxia inducible factor (HIF-1)α activator (DMOG), (iii) 50% (v/v) macrophage conditioned media (MCM), ± 100 nM AD-01. Unbiased, untargeted proteomic analysis was conducted via LC-MS/MS to identify protein targets of AD-01.

RESULTS

FKBPL expression is substantially downregulated in mice after hindlimb ischemia (p < 0.05, protein; p < 0.001, mRNA), correlating with increased neovascularization and altered vascular adhesion molecule expression. In our real-time advanced 3D microfluidics model, hypoxia suppressed FKBPL (p < 0.05) and VE-cadherin (p < 0.001) expression, leading to increased endothelial cell number and migration (p < 0.001), which was restored by AD-01 treatment (p < 0.01). Under inflammatory conditions, FKBPL (p < 0.01) and HIF-1α (p < 0.05) expression was elevated, correlating with increased endothelial cell migration (p < 0.05). Unlike hypoxia, AD-01 did not influence endothelial cell migration under inflammatory conditions, but normalized FKBPL (p < 0.001), HIF-1α (p < 0.05) and CD31 (P < 0.05), expression, in 3D microfluidic cell culture. Proteomic analysis revealed that AD-01 treatment in hypoxia enhanced the abundance of tissue remodelling and vascular integrity proteins including collagen alpha-1(XIX) chain and junctional cadherin associated-5 (JCAD) proteins.

CONCLUSIONS

FKBPL represents an important novel mechanism in hypoxia and inflammation-induced angiogenesis. The FKBPL-based therapeutic peptide, AD-01, could be a viable treatment option for CVD-related endothelial cell dysfunction.

Tissue macrophages: origin, heterogenity, biological functions, diseases and therapeutic targets

Macrophages are immune cells belonging to the mononuclear phagocyte system. They play crucial roles in immune defense, surveillance, and homeostasis. This review systematically discusses the types of hematopoietic progenitors that give rise to macrophages, including primitive hematopoietic progenitors, erythro-myeloid progenitors, and hematopoietic stem cells. These progenitors have distinct genetic backgrounds and developmental processes. Accordingly, macrophages exhibit complex and diverse functions in the body, including phagocytosis and clearance of cellular debris, antigen presentation, and immune response, regulation of inflammation and cytokine production, tissue remodeling and repair, and multi-level regulatory signaling pathways/crosstalk involved in homeostasis and physiology. Besides, tumor-associated macrophages are a key component of the TME, exhibiting both anti-tumor and pro-tumor properties. Furthermore, the functional status of macrophages is closely linked to the development of various diseases, including cancer, autoimmune disorders, cardiovascular disease, neurodegenerative diseases, metabolic conditions, and trauma. Targeting macrophages has emerged as a promising therapeutic strategy in these contexts. Clinical trials of macrophage-based targeted drugs, macrophage-based immunotherapies, and nanoparticle-based therapy were comprehensively summarized. Potential challenges and future directions in targeting macrophages have also been discussed. Overall, our review highlights the significance of this versatile immune cell in human health and disease, which is expected to inform future research and clinical practice.

Cancer-intrinsic Cxcl5 orchestrates a global metabolic reprogramming for resistance to oxidative cell death in 3D

Pancreatic ductal adenocarcinoma is characterized by a three-dimensional (3D) tumor microenvironment devoid of oxygen and nutrients but enriched in extracellular matrix, which acts as a physical and chemical barrier. In 3D, cancer cells reprogram their metabolic pathways in ways that help them survive hostile conditions. However, little is known about the metabolic phenotypes of cancer cells in 3D and the intrinsic cues that modulate them. We found that Cxcl5 deletion restricted pancreatic tumor growth in a 3D spheroid-in-Matrigel culture system without affecting cancer cell growth in 2D culture. Cxcl5 deletion impaired 3D-specific global metabolic reprogramming, resistance to hypoxia-induced cell death, and upregulation of Hif1α and Myc. Overexpression of Hif1α and Myc, however, effectively restored 3D culture-induced metabolic reconfiguration, growth, redox homeostasis, and mitochondrial function in Cxcl5-/- cells, reducing ferroptosis. We also found that pancreatic cancer patients with higher expression of hypoxia and metabolism-related genes whose expression is well-correlated with CXCL5 generally have poorer prognosis. Together, our findings identify an unanticipated role of Cxcl5 in orchestrating the cancer metabolic reprogramming in 3D culture that is required for energy and biomass maintenance and that restricts oxidative cell death. Thus, our results provide a rationale for targeting CXCL5 as a promising therapeutic strategy.

The multifaceted roles of macrophages in the transition from hepatitis to hepatocellular carcinoma: From mechanisms to therapeutic strategies

Macrophages are central to the progression from hepatitis to hepatocellular carcinoma (HCC), with their remarkable plasticity and ability to adapt to the changing liver microenvironment. Chronic inflammation, fibrosis, and ultimately tumorigenesis are driven by macrophage activation, making them key regulators of liver disease progression. This review explores the diverse roles of macrophages in the transition from hepatitis to HCC. In the early stages of hepatitis, macrophages are essential for pathogen clearance and tissue repair. However, chronic activation leads to prolonged inflammation, which exacerbates liver damage and promotes fibrosis. As the disease progresses to liver fibrosis, macrophages interact with hepatic stellate cells, fostering a pro-tumorigenic microenvironment that supports HCC development. In hepatocarcinogenesis, macrophages contribute to tumor initiation, growth, metastasis, immune evasion, cancer stem cell maintenance, and angiogenesis. Their functional plasticity enables them to adapt to the tumor microenvironment, thereby promoting tumor progression and resistance to therapy. Targeting macrophages represents a promising strategy for preventing and treating HCC. Therapeutic approaches, including reprogramming macrophage phenotypes to enhance anti-tumor immunity, blocking macrophage recruitment and activation, and utilizing nanoparticle-based drug delivery systems, may provide new avenues for combating HCC by modulating macrophage functions and tumor microenvironment dynamics.

The role of HIF-1α in hypoxic metabolic reprogramming in osteoarthritis

The joint dysfunction caused by osteoarthritis (OA) is increasingly becoming a major challenge in global healthcare, and there is currently no effective strategy to prevent the progression of OA. Therefore, better elucidating the relevant mechanisms of OA occurrence and development will provide theoretical basis for formulating new prevention and control strategies. Due to long-term exposure of cartilage tissue to the hypoxic microenvironment of joints, metabolic reprogramming changes occur. Hypoxia-inducible factor-1alpha (HIF-1α), as a core gene regulating hypoxia response in vivo, plays an important regulatory role in the hypoxic metabolism of chondrocytes. HIF-1α adapts to the hypoxic microenvironment by regulating metabolic reprogramming changes such as glycolysis, oxidative phosphorylation (OXPHOS), amino acid metabolism, and lipid metabolism in OA chondrocytes. In addition, HIF-1α also regulates macrophage polarization and synovial inflammation, chondrocytes degeneration and extracellular matrix (ECM) degradation, subchondral bone remodeling and angiogenesis in the hypoxic microenvironment of OA, and affects the pathophysiological progression of OA. Consequently, the regulation of chondrocytes metabolic reprogramming by HIF-1α has become an important therapeutic target for OA. Therefore, this article reviews the mechanism of hypoxia affecting chondrocyte metabolic reprogramming, focusing on the regulatory mechanism of HIF-1α on chondrocyte metabolic reprogramming, and summarizes potential effective ingredients or targets targeting chondrocyte metabolic reprogramming, in order to provide more beneficial basis for the prevention and treatment of clinical OA and the development of effective drugs.

Macrophage metabolic reprogramming: A trigger for cardiac damage in autoimmune diseases

Macrophage metabolic reprogramming has a central role in the progression of autoimmune and auto-inflammatory diseases. The heart is a major target organ in many autoimmune conditions and can sustain functional and structural impairments, potentially leading to irreversible cardiac damage. There is mounting clinical evidence pointing to a link between autoimmune disease and cardiac damage. However, this association remains poorly understood, and numerous patients do not receive appropriate preventive measures, which poses serious cardiovascular risks and significantly impacts their quality of life. This review discusses the relationship between macrophage metabolic reprogramming and cardiac damage in patients with autoimmune diseases and the role of adaptive immunity in macrophage reprogramming. It also provides an overview of the immunosuppressive therapies used at present. Exploiting the properties of macrophage reprogramming could lead to development of novel treatments for patients with autoimmune-related cardiac damage.

The Role of Reductive Stress in the Pathogenesis of Endocrine-Related Metabolic Diseases and Cancer

Reductive stress (RS), characterized by excessive accumulation of reducing equivalents such as NADH and NADPH, is emerging as a key factor in metabolic disorders and cancer. While oxidative stress (OS) has been widely studied, RS and its complex interplay with endocrine regulation remain less understood. This review explores molecular circuits of bidirectional crosstalk between metabolic hormones and RS, focusing on their role in diabetes, obesity, cardiovascular diseases, and cancer. RS disrupts insulin secretion and signaling, exacerbates metabolic inflammation, and contributes to adipose tissue dysfunction, ultimately promoting insulin resistance. In cardiovascular diseases, RS alters vascular smooth muscle cell function and myocardial metabolism, influencing ischemia-reperfusion injury outcomes. In cancer, RS plays a dual role: it enhances tumor survival by buffering OS and promoting metabolic reprogramming, yet excessive RS can trigger proteotoxicity and mitochondrial dysfunction, leading to apoptosis. Recent studies have identified RS-targeting strategies, including redox-modulating therapies, nanomedicine, and drug repurposing, offering potential for novel treatments. However, challenges remain, particularly in distinguishing physiological RS from pathological conditions and in overcoming therapy-induced resistance. Future research should focus on developing selective RS biomarkers, optimizing therapeutic interventions, and exploring the role of RS in immune and endocrine regulation.

Impact of Hypoxia-Inducible Factor-1α on Host Immune Metabolism and Tissue Damage During Mycobacterium bovis Infection

Hypoxia-inducible factor-1α (HIF-1α) is a pivotal regulator of metabolic and inflammatory responses. This study investigated the role of HIF-1α in Mycobacterium bovis infection and its effects on host immune metabolism and tissue damage. We evaluated the expression of immunometabolism markers and matrix metalloproteinases (MMPs) in cells infected with M. bovis, and following HIF-1α inhibition in vitro. To understand the implications of HIF-1α inhibition on disease progression, mice at different infection stages were treated with the HIF-1α inhibitor, YC-1. Our results revealed an upregulation of HIF-1α in macrophages after M. bovis infection, facilitating enhanced M1 macrophage polarization. Blockade of HIF-1α moderated these responses but escalated MMP activity, hindering bacterial control. Consistent with our in vitro results, early-stage treatment of mice with YC-1 aggravated pathological alterations and tissue damage, while late-stage HIF-1α inhibition proved beneficial in managing the disease. Our findings underscored the nuanced role of HIF-1α across different phases of M. bovis infection.

Renal-Clearable Metalloporphyrin Complex-Based Nanosonosensitizers Using Photoacoustic Imaging Guiding to Enhance Sonodynamic Cancer Therapy

Sonodynamic therapy (SDT) is a noninvasive approach to tumor treatment, with ongoing efforts being focused on developing highly effective sonosensitizers with low toxicity. Herein, a liquid-phase stripping technique was introduced as a simple reflux method for synthesizing ultrasmall Mn-PCN-224 nanodots (MM NDs). Compared with PCN-224 nanodots, the synthesized MM NDs, which function as renal-clearable nanoagents, produced 2.42 times more reactive oxygen species (ROS) under identical ultrasound (US) irradiation conditions. In vivo and in vitro experiments revealed that A549 lung cancer cells treated with MM NDs under US irradiation and H2O2 exhibited a relative cell viability of ∼9% and a tumor inhibition rate of ∼91%. This result demonstrates that MM NDs can efficiently increase the effectiveness of SDT by leveraging their catalase-like activity and ultrasmall size (4 nm) to prevent ROS quenching. Furthermore, these nanoagents could be effectively utilized for photoacoustic (PA) imaging to track their accumulation in tumors and monitor the alleviation of the hypoxic tumor microenvironment. Notably, MM ND-mediated SDT demonstrated superior penetration depth compared to PDT, making it more effective in inhibiting contralateral tumors while facilitating deep-tissue treatment. Thus, this study introduces renal-clearable nanoagents with promising potential for PA-guided SDT, thereby paving the way for more effective tumor treatment strategies.

Programmed Cell Death in Rheumatoid Arthritis

Rheumatoid arthritis (RA) is a chronic, progressive, systemic autoimmune disease characterised by synovial inflammation, synovial pannus formation and subsequent destruction of articular cartilage and bone. Programmed cell death (PCD), encompassing apoptosis, autophagy, pyroptosis, necroptosis, and ferroptosis, plays a pivotal role in the pathogenesis of RA. An imbalance in PCD causes a variety of immune cells to release large amounts of inflammatory factors and mediators that exacerbate not only chronic synovial inflammation, but also bone and joint damage. The purpose of this article is to review the relevant studies between PCD and RA, with the aim of providing further insights and considerations for a deeper understanding of the pathogenesis of RA and to guide clinical management.

Roles of Post-Translational Modifications of Transcription Factors Involved in Breast Cancer Hypoxia

BC is the most commonly diagnosed cancer and the second leading cause of cancer death among women worldwide. Cellular stress is a condition that leads to disrupted homeostasis by extrinsic and intrinsic factors. Among other stressors, hypoxia is a driving force for breast cancer (BC) progression and a general hallmark of solid tumors. Thus, intratumoral hypoxia is an important determinant of invasion, metastasis, treatment failure, prognosis, and patient mortality. Acquisition of the epithelial-mesenchymal transition (EMT) phenotype is also a consequence of tumor hypoxia. The cellular response to hypoxia is mainly regulated by the hypoxia signaling pathway, governed by hypoxia-inducible factors (HIFs), mainly HIF1α. HIFs are a family of transcription factors (TFs), which induce the expression of target genes involved in cell survival and proliferation, metabolic reprogramming, angiogenesis, resisting apoptosis, invasion, and metastasis. HIF1α cooperates with a large number of other TFs. In this review, we focused on the crosstalk and cooperation between HIF1α and other TFs involved in the cellular response to hypoxia in BC. We identified a cluster of TFs, proposed as the HIF1α-TF interactome, that orchestrates the transcription of target genes involved in hypoxia, due to their post-translational modifications (PTMs), including phosphorylation/dephosphorylation, ubiquitination/deubiquitination, SUMOylation, hydroxylation, acetylation, S-nitrosylation, and palmitoylation. PTMs of these HIF1α-related TFs drive their stability and activity, degradation and turnover, and the bidirectional translocation between the cytoplasm or plasma membrane and nucleus of BC cells, as well as the transcription/activation of proteins encoded by oncogenes or inactivation of tumor suppressor target genes. Consequently, PTMs of TFs in the HIF1α interactome are crucial regulatory mechanisms that drive the cellular response to oxygen deprivation in BC cells.

Spring viremia of carp virus infection induces hypoxia response in zebrafish by stabilizing hif1α

The hypoxia signaling pathway controls hypoxia adaptation and tolerance of organisms, which is regulated by multiple mechanisms. Viral infection elicits various pathophysiological responses in the host. However, whether viral infection can affect the hypoxia response is not yet fully understood. In this study, we found that Spring viremia of carp virus (SVCV) infection in zebrafish caused symptoms similar to those in zebrafish under hypoxic conditions. Further assays indicated that SVCV infection activated the hypoxia signaling pathway in zebrafish. In addition, SVCV infection caused increased glycolysis and reactive oxygen species (ROS) levels in cells. Mechanistically, SVCV-G protein interacted with hif1α-a/b and attenuated their K48-linked polyubiquitination, leading to their stabilization and subsequent enhancement of target gene expression. Moreover, treatment with the HIF1α-specific inhibitor PX478 enhanced the antiviral ability against SVCV infection in zebrafish and zebrafish cells. This study reveals a relationship between SVCV infection and the hypoxia signaling pathway in fish and provides a strategy for reducing the damage of viral disease in the aquaculture industry.

IMPORTANCE

Viral infection triggers various pathophysiological responses in the host. The hypoxia signaling pathway controls hypoxia adaptation and tolerance of organisms. However, whether viral infection can affect the hypoxia response is not yet fully understood. This study showed that Spring viremia of carp virus (SVCV) infection activated the hypoxia signaling pathway and induced a hypoxia response. The SVCV-G protein interacted with hif1α-a/b and reduced their K48-linked polyubiquitination, leading to their stabilization and subsequent enhancement of target gene expression. Additionally, treatment with the HIF1α-specific inhibitor PX478 enhanced the antiviral ability against SVCV infection in zebrafish and zebrafish cells. Our findings not only reveal a relationship between SVCV infection and the hypoxia signaling pathway in fish but also provide a strategy for reducing the damage of viral disease in the aquaculture industry.

Invasive aspergillosis in critically ill patients with diabetes mellitus: a systematic review and meta-analysis

BACKGROUND

In the intensive care unit (ICU), invasive aspergillosis (IA) has a poor prognosis. Some studies report a positive association between diabetes mellitus (DM) and IA in critically ill patients, but the relationship between DM and IA in the ICU remains controversial. We aimed to clarify the relationship between DM and IA among patients in the ICU in a systematic review and meta-analysis.

METHODS

We retrieved all reports published in PubMed, EMBASE, and the Cochrane Library databases before July 12, 2023. We calculated odds ratios (ORs) and 95% confidence intervals (CIs) to evaluate the relationship between DM and IA. Subgroup analyses were conducted to further analyze sources of heterogeneity. Heterogeneity was evaluated using the Cochran's Q test and I2 statistic. Additionally, we evaluated publication bias using funnel plots, Egger's test, and Begg's test. Finally, sensitivity analysis was conducted to evaluate the robustness of the results.

RESULTS

Twenty studies with 6155 participants were included in this meta-analysis. We found a positive association between DM and IA among patients in the ICU (OR = 1.18, 95% CI:1.01 to 1.39; p = 0.04). The heterogeneity was not significant (I² = 5%; p = 0.39) and publication bias was not significant (Egger's test: p = 0.654; Begg's test: p = 0.417). The results of sensitivity analysis supported a stable association between DM and IA. Subgroup analysis indicated that patients' comorbidities might be a potential source of heterogeneity. Additionally, patients with DM had a significantly higher risk of COVID-19-associated pulmonary aspergillosis (CAPA) than those without DM (OR = 1.40, 95% CI: 1.15 to 1.70; p < 0.001). The heterogeneity was not significant (I² = 0%; p = 0.91). In the subgroup with influenza, the OR of the relationship between DM and IA was 0.81 (95% CI: 0.54, 1.23; p = 0.32; heterogeneity: p = 0.36; I² = 8%).

CONCLUSIONS

Patients with DM in the ICU showed a higher risk of developing IA than patients in the ICU without DM. DM was a significant risk factor for IA, with the highest risk observed in critically ill patients diagnosed with CAPA.

Supramolecular discrimination and diagnosis-guided treatment of intracellular bacteria

Pathogenic intracellular bacteria pose a significant threat to global public health due to the barriers presented by host cells hindering the timely detection of hidden bacteria and the effective delivery of therapeutic agents. To address these challenges, we propose a tandem diagnosis-guided treatment paradigm. A supramolecular sensor array is developed for simple, rapid, accurate, and high-throughput identification of intracellular bacteria. This diagnostic approach executes the significant guiding missions of screening a customized host-guest drug delivery system by disclosing the rationale behind the discrimination. We design eight azocalix[4]arenes with differential active targeting, cellular internalization, and hypoxia responsiveness to penetrate cells and interact with bacteria. Loaded with fluorescent indicators, these azocalix[4]arenes form a sensor array capable of discriminating eight intracellular bacterial species without cell lysis or separation. By fingerprinting specimens collected from bacteria-infected mice, the facilitated accurate diagnosis offers valuable guidance for selecting appropriate antibiotics. Moreover, mannose-modified azocalix[4]arene (ManAC4A) is screened as a drug carrier efficiently taken up by macrophages. Doxycycline loaded with ManAC4A exhibits improved efficacy against methicillin-resistant Staphylococcus aureus-infected peritonitis. This study introduces an emerging paradigm to intracellular bacterial diagnosis and treatment, offering broad potential in combating bacterial infectious diseases.

Harnessing hypoxia: bacterial adaptation and chronic infection in cystic fibrosis

The exquisite ability of bacteria to adapt to their environment is essential for their capacity to colonize hostile niches. In the cystic fibrosis (CF) lung, hypoxia is among several environmental stresses that opportunistic pathogens must overcome to persist and chronically colonize. Although the role of hypoxia in the host has been widely reviewed, the impact of hypoxia on bacterial pathogens has not yet been studied extensively. This review considers the bacterial oxygen-sensing mechanisms in three species that effectively colonize the lungs of people with CF, namely Pseudomonas aeruginosa, Burkholderia cepacia complex, and Mycobacterium abscessus and draws parallels between their three proposed oxygen-sensing two-component systems: BfiSR, FixLJ, and DosRS, respectively. Moreover, each species expresses regulons that respond to hypoxia: Anr, Lxa, and DosR, and encode multiple proteins that share similar homologies and function. Many adaptations that these pathogens undergo during chronic infection, including antibiotic resistance, protease expression, or changes in motility, have parallels in the responses of the respective species to hypoxia. It is likely that exposure to hypoxia in their environmental habitats predispose these pathogens to colonization of hypoxic niches, arming them with mechanisms than enable their evasion of the immune system and establish chronic infections. Overcoming hypoxia presents a new target for therapeutic options against chronic lung infections.

Intestinal E. coli-produced yersiniabactin promotes profibrotic macrophages in Crohn's disease

Inflammatory bowel disease (IBD)-associated fibrosis causes significant morbidity. Mechanisms are poorly understood but implicate the microbiota, especially adherent-invasive Escherichia coli (AIEC). We previously demonstrated that AIEC producing the metallophore yersiniabactin (Ybt) promotes intestinal fibrosis in an IBD mouse model. Since macrophages interpret microbial signals and influence inflammation/tissue remodeling, we hypothesized that Ybt metal sequestration disrupts this process. Here, we show that macrophages are abundant in human IBD-fibrosis tissue and mouse fibrotic lesions, where they co-localize with AIEC. Ybt induces profibrotic gene expression in macrophages via stabilization and nuclear translocation of hypoxia-inducible factor 1-alpha (HIF-1α), a metal-dependent immune regulator. Importantly, Ybt-producing AIEC deplete macrophage intracellular zinc and stabilize HIF-1α through inhibition of zinc-dependent HIF-1α hydroxylation. HIF-1α+ macrophages localize to sites of disease activity in human IBD-fibrosis strictures and mouse fibrotic lesions, highlighting their physiological relevance. Our findings reveal microbiota-mediated metal sequestration as a profibrotic trigger targeting macrophages in the inflamed intestine.

GP73 reinforces cytotoxic T-cell function by regulating HIF-1α and increasing antitumor efficacy

BACKGROUND

Immunotherapy that targets immune checkpoints has achieved revolutionary success, but its application in solid tumors remains limited, highlighting the need for reliable enhancement of the efficacy of immunotherapy. Golgi protein 73 (GP73), a Golgi membrane protein, has been implicated in various cellular processes, including immune regulation. Recent studies suggested that GP73 may play a role in modulating the immune response in patients with cancer. In this study, we investigated the mechanism by which GP73 regulates T-cell-mediated antitumor immunity within the tumor microenvironment.

METHODS

We used T-cell specific GP73 knockout mice to establish MC38 and B16 tumor models to investigate the impact of GP73-deficient T cells on tumor growth. Single-cell sequencing was subsequently employed to classify tumor-infiltrating immune cells and assess changes in cytokines and metabolic genes. Through RNA sequencing, real-time quantitative PCR, western blotting, flow cytometry, seahorse analysis, glucose uptake, and L-lactic acid secretion assays, we explored how GP73 regulates hypoxia-inducible factor 1α (HIF-1α) to influence T-cell antitumor functionality. Furthermore, we established adoptive transfer experiments to study the ability of GP73-overexpressing T cells to combat tumors. Blood samples of patient with clinical tumor were collected to assess the relationship between immunotherapy efficacy and T-cell GP73 levels.

RESULTS

In this study, the absence of GP73 in mouse T cells promoted tumor growth and metastasis, accompanied by a decrease in the proportion of cytotoxic CD8+T cell subsets infiltrating the tumor and an increase in exhausted CD8+ T-cell subsets. Further analysis revealed that the effector function of CD8+T cells in tumors relies on glycolysis regulated by HIF-1α rather than immune checkpoints. GP73-deficient T cells exhibit severely impaired glycolysis in hypoxic environments, whereas ectopic GP73 expression restores HIF-1α levels. In adoptive immunotherapy, overexpression of GP73 in T cells inhibits tumor growth. In cytotoxicity assays, knockdown of GP73 affected the ability of CD8+T cells to kill target cells. Clinically, tumor immunotherapy partial response patients present significantly elevated levels of GP73 expression in T cells.

CONCLUSIONS

These findings reveal the role of GP73 in regulating T-cell glycolysis and may lead to new therapeutic strategies for the prognosis and treatment of clinical tumor immunotherapy.

Maintenance of Cardiac Microenvironmental Homeostasis: A Joint Battle of Multiple Cells

Various cells such as cardiomyocytes, fibroblasts and endothelial cells constitute integral components of cardiac tissue. The health and stability of cardiac ecosystem are ensured by the action of a certain type of cell and the intricate interactions between multiple cell types. The dysfunctional cells exert a profound impact on the development of cardiovascular diseases by involving in the pathological process. In this paper, we introduce the dynamic activity, cell surface markers as well as biological function of the various cells in the heart. Besides, we discuss the multiple signaling pathways involved in the cardiac injury including Hippo/YAP, TGF-β/Smads, PI3K/Akt, and MAPK signaling. The complexity of different cell types poses a great challenge to the disease treatment. By characterizing the roles of various cell types in cardiovascular diseases, we sought to discuss the potential strategies for preventing and treating cardiovascular diseases.

Nicorandil restores endothelial cell Kir6.2 expression to alleviate neuropathic pain in mice after chronic constriction injury

The clinical management of neuropathic pain (NP) remains a significant challenge, as current pharmacological treatments do not fully meet clinical needs. Nicorandil, a potassium ATP channel agonist widely used in cardiovascular medicine, has recently been shown to have significant potential for analgesia. This study aimed to investigate the effects and mechanisms of nicorandil in a chronic constriction injury (CCI) mouse model. Nicorandil significantly alleviated pain hypersensitivity and reduced neuronal injury in the sciatic nerve (SN) and dorsal root ganglion (DRG) post-CCI. Nicorandil primarily affected endothelial cells and Schwann cells in the sciatic nerve, restoring the expression of the KATP channel subunit Kir6.2. Furthermore, nicorandil attenuated the hypoxia-induced apoptosis program in sciatic nerve endothelial cells, leading to reduced expression of apoptotic proteins, which provided significant endothelial protection, improved blood-nerve barrier leakage, and decreased the release of DRG inflammatory factors and pain neurotransmitter substance P. In vitro, nicorandil attenuated the apoptosis of human umbilical vein endothelial cells (HUVECs) in a hypoxic environment while maintaining cellular functions. In addition, administering the KATP channel inhibitor glibenclamide in vitro further confirmed the crucial role of Kir6.2 in reducing endothelial hypoxic stress, as confirmed by transmission electron microscopy and behavioural experiments. Overall, these findings indicate that nicorandil significantly ameliorates CCI-induced NP in mice by targeting Kir6.2 in sciatic nerve endothelial cells, thus inhibiting pain sensitization.

Gasping for air: HIF2α in asthma

Despite protective roles in various type of infection and in would healing, T helper (Th)2 cells are drivers of inflammation in allergic asthma. In this issue of Immunity, Zou et al. demonstrate the crucial involvement of hypoxia inducible factor (HIF)2α in promoting the differentiation of inflammatory Th2 cells, suggesting HIF2α as a promising therapeutic target for the treatment of allergic asthma.

Hypoxia-inducible factor 2α promotes pathogenic polarization of stem-like Th2 cells via modulation of phospholipid metabolism

T helper 2 (Th2) cells orchestrate immunity against parasite infection and promote tissue repair but promote pathology in asthma and tissue fibrosis. Here, we examined the mechanisms driving pathogenic differentiation of Th2 cells. Single-cell analyses of CD4+ T cells from asthma and chronic rhinosinusitis patients revealed high expression of the hypoxia-inducible factor (HIF)2α in Th2 cells. In mice, HIF2α deficiency impaired Th2 differentiation and alleviated asthmatic inflammation. Single-cell and lineage tracing approaches delineated a differentiation trajectory from TCF1+Ly108+ stem-like Th2 cells to the ST2+CD25+ pathogenic progeny, depending on a HIF2α-GATA3 circuit that modulated phospholipid metabolism and T cell receptor (TCR)-phosphatidylinositol 3-kinase (PI3K)-protein kinase B (AKT) activation via transcriptional regulation of the inositol polyphosphate multikinase (IPMK). Overexpression of IPMK in HIF2α-deficient cells promoted Phosphatidylinositol (3,4,5)-trisphosphate (PIP3) synthesis and pathogenic Th2 cell differentiation, whereas pharmacological inhibition of HIF2α impaired pathogenic differentiation of Th2 cells and mitigated airway inflammation. Our findings provide insight into the contextual cues that promote Th2-mediated pathology and suggest HIF2α as a therapeutic target in asthma.

Understanding the development of tuberculous granulomas: insights into host protection and pathogenesis, a review in humans and animals

Granulomas, organized aggregates of immune cells which form in response to Mycobacterium tuberculosis (Mtb), are characteristic but not exclusive of tuberculosis (TB). Despite existing investigations on TB granulomas, the determinants that differentiate host-protective granulomas from granulomas that contribute to TB pathogenesis are often disputed. Thus, the goal of this narrative review is to help clarify the existing literature on such determinants. We adopt the a priori view that TB granulomas are host-protective organelles and discuss the molecular and cellular determinants that induce protective granulomas and those that promote their failure. While reports about protective TB granulomas and their failure may initially seem contradictory, it is increasingly recognized that either deficiencies or excesses of the molecular and cellular components in TB granuloma formation may be detrimental to the host. More specifically, insufficient or excessive expression/representation of the following components have been reported to skew granulomas toward the less protective phenotype: (i) epithelioid macrophages; (ii) type 1 adaptive immune response; (iii) type 2 adaptive immune response; (iv) tumor necrosis factor; (v) interleukin-12; (vi) interleukin-17; (vii) matrix metalloproteinases; (viii) hypoxia in the TB granulomas; (ix) hypoxia inducible factor-1 alpha; (x) aerobic glycolysis; (xi) indoleamine 2,3-dioxygenase activity; (xii) heme oxygenase-1 activity; (xiii) immune checkpoint; (xiv) leukotriene A4 hydrolase activity; (xv) nuclear-factor-kappa B; and (xvi) transforming growth factor-beta. Rather, more precise and timely coordinated immune responses appear essential for eradication or containment of Mtb infection. Since there are several animal models of infection with Mtb, other species within the Mtb complex, and the surrogate Mycobacterium marinum - whether natural (cattle, elephants) or experimental (zebrafish, mouse, guinea pig, rabbit, mini pig, goat, non-human primate) infections - we also compared the TB granulomatous response and other pathologic lung lesions in various animals infected with one of these mycobacteria with that of human pulmonary TB. Identifying components that dictate the formation of host-protective granulomas and the circumstances that result in their failure can enhance our understanding of the macrocosm of human TB and facilitate the development of novel remedies - whether they be direct therapeutics or indirect interventions - to efficiently eliminate Mtb infection and prevent its pathologic sequelae.

Integrated miRNA-seq and functional analyses reveal the regulatory role of sha-miR-92a_L + 2R + 4 via targeting vegfaa in rainbow trout (Oncorhynchus mykiss) responding to acute hypoxia and reoxygenation stress

BACKGROUND

Hypoxia negatively affects the behavior, growth, reproduction and survival of fish, causing serious economic losses to aquaculture. Rainbow trout (Oncorhynchus mykiss), an important economic fish worldwide, belongs to a hypoxia-sensitive fish species, however, little is known about the regulatory mechanism of microRNAs (miRNAs) under hypoxia stress.

RESULTS

Rainbow trout were subjected to hypoxia stress for 3 h (H3h_L), 12 h (H12h_L), 24 h (H24h_L) and 3 h reoxygenation (R3h_L) to systemically evaluate the changes of miRNA expression profiles in liver, and functions of sha-miR-92a_L + 2R + 4 were investigated. We found 17, 144, 57 and 55 differentially expressed (DE) miRNAs in the H3h_L vs. control (N_L), H12h_L vs. N_L, H24h_L vs. N_L and R3h_L vs. N_L comparisons, respectively. Enrichment analysis revealed that the targets of DE miRNAs were significantly enriched in HIF signaling pathway, VEGF signaling pathway, FoxO signaling pathway and glycolysis/gluconeogenesis. Through miRNA-mRNA interaction and weighted gene co-expression network analysis (WGCNA), five key DE miRNAs (sha-miR-92a_L + 2R + 4, ssa-miR-128-3p, ssa-miR-101b-3p_R + 1, ola-miR-199a-5p_R + 2 and tni-miR-199_1ss18CG) were identified, which can target at least two hypoxia-responsive genes, such as vegfaa, ho, glut1a and junb. Functional analysis found that sha-miR-92a_L + 2R + 4 directly regulated vegfaa expression by targeting its 3'-UTR, overexpression of sha-miR-92a_L + 2R + 4 significantly decreased vegfaa expression in rainbow trout liver cells, while opposite results were obtained after transfection of sha-miR-92a_L + 2R + 4 inhibitor. Furthermore, overexpressed sha-miR-92a_L + 2R + 4 promoted rainbow trout liver cell proliferation and inhibited apoptosis.

CONCLUSION

This study deepens our understanding of the crucial roles of miRNAs under hypoxia stress in rainbow trout. These results can contribute to devise strategies for improving rainbow trout survival rate and aquaculture production during hypoxia stress and help speeding up the selective breeding of hypoxia-tolerant rainbow trout.

Understanding MDS stem cells: Advances and limitations

In work spanning several decades, extensive studies have focused on the properties of malignant stem cells that drive the pathogenesis of acute myeloid leukemia (AML). However, relatively little attention has been devoted to several serious myeloid malignancies that occur prior to the onset of frank leukemia, including myelodysplastic syndrome (MDS). Like leukemia, MDS is hypothesized to arise from a pool of immature malignant stem and progenitor cells (MDS-SCs) that serve as a reservoir for disease evolution and progression1. While multiple studies have sought to identify and characterize the biology and vulnerabilities of MDS-SCs, yet translation of scientific concepts to therapeutically impactful regimens has been limited. Here, we evaluate the currently known properties of MDS-SCs as well as the post-transcriptional mechanisms that drive MDS pathogenesis at a stem and progenitor level. We highlight limits and gaps in our characterization and understanding of MDS-SCs and address the extent to which the properties of MDS-SC are (and can be) inferred from the characterization of LSCs.

Haemoglobin levels are associated with echocardiographic measures in a Finnish midlife population

BACKGROUND

Within normal variation, higher haemoglobin (Hb) levels are associated with unhealthier body composition, adverse metabolism and cardiovascular disease (CVD)-related mortality. Global longitudinal strain (GLS) is a direct, well validated and reproducible echocardiographic measure for the evaluation of cardiac contractile function, providing additional prognostic value for prediction of a variety of cardiac events. This study investigated the relation between Hb levels and cardiac function measures, including GLS, in a Finnish midlife population.

MATERIALS AND METHODS

Echocardiography was carried out in a subpopulation of the Northern Finland Birth Cohort 1966 at age of 46 (n = 1155). GLS was available for n = 796. Subjects with diabetes, severe cardiac diseases, echocardiographic abnormalities, heart rate ≥85 bpm during echocardiography or Hb level outside the Finnish reference intervals (117-155 g/L for females and 134-167 g/L for males) were excluded from the analysis. The study population included 635 subjects (46% males). The data were analysed in Hb tertiles and in multivariable linear regression models.

RESULTS

The highest Hb tertile had adverse anthropometric and metabolic parameters compared to other Hb tertiles. Of the studied echocardiographic parameters, the highest Hb tertile had the highest left ventricular mass (LVM, p < .01), LVM index (LVMi, p < .05), LV end-diastolic volume (LVEDV, p < .05), posterior wall thickness (PWT, p < .001), relative wall thickness (RWT, p < .05) and the lowest absolute GLS (p < .001) but no difference in LV ejection fraction (LVEF) was observed between the Hb tertiles. In linear models, when adjusted for covariates, Hb levels were associated positively and independently with GLS (B = 0.153 [0.071; 0.235]) and LVM (B = 0.272 [0.193; 0.350]).

CONCLUSIONS

Higher Hb levels are associated with an adverse metabolic and inflammatory profile and more adverse cardiac function measures, including GLS, in both sexes in midlife.

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.

NIR-II Image-Guided Wound Healing in Hypoxic Diabetic Foot Ulcers: The Potential of Ergothioneine-Luteolin-Chitin Hydrogels

Hypoxic diabetic foot ulcers (HDFUs) pose a challenging chronic condition characterized by oxidative stress damage, bacterial infection, and persistent inflammation. This study introduces a novel therapeutic approach combining ergothioneine (EGT), luteolin (LUT), and quaternized chitosan oxidized dextran (QCOD) to address these challenges and facilitate wound healing in hypoxic DFUs. In vitro, assessments have validated the biosafety, antioxidant, and antimicrobial properties of the ergothioneine-luteolin-chitin (QCOD@EGT-LUT) hydrogel. Furthermore, near-infrared II (NIR-II) fluorescence image-guided the application of QCOD@EGT-LUT hydrogel in simulated HDFUs. Mechanistically, QCOD@EGT-LUT hydrogel modulates the diabetic wound microenvironment by reducing reactive oxygen species (ROS). In vivo studies demonstrated increased expression of angiogenic factors mannose receptor (CD206) and latelet endothelial cell adhesion molecule-1 (PECAM-1/CD31), coupled with decreased inflammatory factors tumor necrosis factor-α (TNF-α) and Interleukin-6 (IL-6), thereby promoting diabetic wound healing through up-regulation of transforming growth factor β-1 (TGF-β1).

Influence of Hypoxia on the Airway Epithelium

The necessity of oxygen for metabolic processes means that hypoxia can lead to serious cell and tissue damage. On the other hand, in some situations, hypoxia occurs under physiological conditions and serves as an important regulation factor. The airway epithelium is specific in that it gains oxygen not only from the blood supply but also directly from the luminal air. Many respiratory diseases are associated with airway obstruction or excessive mucus production thus leading to luminal hypoxia. The main goal of this review is to point out how the airway epithelium reacts to hypoxic conditions. Cells detect low oxygen levels using molecular mechanisms involving hypoxia-inducible factors (HIFs). In addition, the cells of the airway epithelium appear to overexpress HIFs in hypoxic conditions. HIFs then regulate many aspects of epithelial cell functions. The effects of hypoxia include secretory cell stimulation and hyperplasia, epithelial barrier changes, and ciliogenesis impairment. All the changes can impair mucociliary clearance, exacerbate infection, and promote inflammation leading to damage of airway epithelium and subsequent airway wall remodeling. The modulation of hypoxia regulatory mechanisms may be one of the strategies for the treatment of obstructive respiratory diseases or diseases with mucus hyperproduction. Keywords: Secretory cells, Motile cilia, Epithelial barrier, Oxygenation, Obstructive respiratory diseases.

Influenza A virus-induced glycolysis facilitates virus replication by activating ROS/HIF-1α pathway

As a highly contagious acute respiratory disease, influenza A virus (A/WSN/1933) poses a huge threat to human health and public health. influenza A virus proliferation relies on glucose metabolism in host cells, yet the effects of influenza A virus on glucose metabolism and the underlying molecular mechanisms remain unclear. Here, we created models of WSN virus-infected mice and A549 cells, along with analyzing metabolomics and transcriptomics data, to investigate how WSN virus infection affects host cell glucose metabolism and specific mechanisms. Analysis of metabolites and gene expression showed that WSN virus infection triggers glycolysis in A549 cells, with notable upregulation of hexokinase 2 (HK2), lactate dehydrogenase A (LDHA), hypoxia-inducible factor-1 alpha (HIF-1α), and elevated lactate levels. Additionally, it leads to mitochondrial impairment and heightened reactive oxygen species (ROS) generation. Elevated levels of glucose may enhance the replication of WSN virus, whereas inhibitors of glycolysis can reduce it. Enhancement of HIF-1α activation facilitated replication of WSN virus through stimulation of lactate synthesis, with the primary influence of glycolysis on WSN virus replication being mediated by ROS/HIF-1α signaling. Mice given HIF-1α inhibitor PTX-478 or glycolysis inhibitor 2-Deoxyglucose (2-DG) exhibited reduced lactate levels and decreased WSN virus replication, along with mitigated weight loss and lung damage. In summary, WSN virus-induced glycolysis has been demonstrated to enhance virus replication through the activation of the ROS/HIF-1α pathway, suggesting potential new targets for combating the virus.

Retinoic acid-induced differentiation and oxidative stress inhibitors increase resistance of human neuroblastoma cells to La Crosse virus-induced cell death

La Crosse Virus (LACV) encephalitis patients are at risk for long-term deficits in cognitive function due to neuronal apoptosis following virus infection. However, the specific etiology underlying neuronal damage remains elusive. In this study, we examined how differentiation and mitotic inhibition of neuroblastoma cells influence their susceptibility to LACV infection and cell death. Treatment of SH-SY5Y cells with retinoic acid induced a neuronal cell phenotype which was similarly susceptible to LACV infection as untreated cells but had significantly delayed virus-induced cell death. Protein and RNA transcript analysis showed that retinoic acid-treated cells had decreased oxidative stress responses to LACV infection compared to untreated cells. Modulation of oxidative stress in untreated cells with specific compounds also delayed cell death, without substantially impacting virus production. Thus, the oxidative stress response of neurons to virus infection may be a key component of neuronal susceptibility to virus-induced cell death.

IMPORTANCE

Encephalitic viruses like La Crosse Virus (LACV) infect and kill neurons. Disease onset and progression is rapid meaning the time frame to treat patients before significant and long-lasting damage occurs is limited. Examining how neurons, the primary cells infected by LACV in the brain, resist virus-induced cell death can provide avenues for determining which pathways to target for effective treatments. In the current study, we studied how changing neuroblastoma growth and metabolism with retinoic acid treatment impacted their susceptibility to LACV-induced cell death. We utilized this information to test compounds for preventing death in these cells.

Suppressing nuclear translocation of microglial PKM2 confers neuroprotection via downregulation of neuroinflammation after mouse cerebral ischemia-reperfusion injury

Pyruvate kinase M2 (PKM2) is a key metabolic enzyme. Yet, its role in cerebral ischemia injury remains unclear. In this study we demonstrated that PKM2 expression was increased in the microglia after mouse cerebral ischemia-reperfusion (I/R) injury. We found that microglial polarization-mediated pro-inflammatory effect was mediated by PKM2 after cerebral I/R. Mechanistically, our results revealed that nuclear PKM2 mediated ischemia-induced microglial polarization through association with acetyl-H3K9. Hif-1α mediated the effect of nuclear PKM2/histone H3 on microglial polarization. PKM2-dependent Histone H3/Hif-1α modifications contributed the expression of CCL2 and induced up-regulation of microglial polarization in peri-infarct, resulting in neuroinflammation. Inhibiting nuclear translocation of microglial PKM2 reduced ischemia-induced pro-inflammation and promoted neuronal survival. Together, this study identifies nucleus PKM2 as a crucial mediator for regulating ischemia-induced neuroinflammation, suggesting PKM2 as a potential therapeutic target in ischemic stroke.

Similarities in B Cell Defects between Aging and Obesity

The aging population is increasing worldwide, and there is also an increase in the aging population living with overweight and obesity, due to changes in lifestyle and in dietary patterns that elderly individuals experience later in life. Both aging and obesity are conditions of accelerated metabolic dysfunction and dysregulated immune responses. In this review, we summarize published findings showing that obesity induces changes in humoral immunity similar to those induced by aging and that the age-associated B cell defects are mainly due to metabolic changes. We discuss the role of the obese adipose tissue in inducing dysfunctional humoral responses and autoimmune Ab secretion.

Hypoxia-adenosinergic regulation of B cell responses

Hypoxic microenvironments induce widespread metabolic changes that have been shown to be critical in regulating innate and adaptive immune responses. Hypoxia-induced changes include the generation of extracellular adenosine followed by subsequent signaling through adenosine receptors on immune cells. This evolutionarily conserved "hypoxia-adenosinergic" pathway of hypoxia → extracellular adenosine → adenosine receptor signaling has been shown to be critical in limiting and redirecting T cell responses including in tumor microenvironments and the gut mucosa. However, the question of whether hypoxic microenvironments are involved in the development of B cell responses has remained unexplored until recently. The discovery that germinal centers (GC), the anatomic site in which B cells undergo secondary diversification and affinity maturation, develop a hypoxic microenvironment has sparked new interest in how this evolutionarily conserved pathway affects antibody responses. In this review we will summarize what is known about hypoxia-adenosinergic microenvironments in lymphocyte development and ongoing immune responses. Specific focus will be placed on new developments regarding the role of the hypoxia-adenosinergic pathway in regulating GC development and humoral immunity.

Therapeutic targeting of hypoxia inducible factor in acute respiratory distress syndrome

Acute respiratory distress syndrome (ARDS) is characterized by bilateral chest infiltration and acute hypoxic respiratory failure. ARDS carries significant morbidity and mortality despite advancements in medical management, calling for the development of novel therapeutic targets. Hypoxia-inducible factor (HIF) is a heterodimeric protein involved in various essential pathways, including metabolic reprogramming, immune modulation, angiogenesis and cell cycle regulation. HIF is routinely degraded in homeostasis conditions via the prolyl hydroxylase domain/von Hippel-Lindau protein pathway. However, HIF is stabilized in ARDS via various mechanisms (oxygen-dependent and independent) as an endogenous protective pathway and plays multifaceted roles in different cell populations. This review focuses on the functional role of HIF and its target genes during ARDS, as well as how HIF has evolved as a therapeutic target in current medical management.

Unraveling the Molecular Mechanisms of SIRT7 in Angiogenesis: Insights from Substrate Clues

Angiogenesis, a vital physiological or pathological process regulated by complex molecular networks, is widely implicated in organismal development and the pathogenesis of various diseases. SIRT7, a member of the Sirtuin family of nicotinamide adenine dinucleotide + (NAD+) dependent deacetylases, plays crucial roles in cellular processes such as transcriptional regulation, cell metabolism, cell proliferation, and genome stability maintenance. Characterized by its enzymatic activities, SIRT7 targets an array of substrates, several of which exert regulatory effects on angiogenesis. Experimental evidence from in vitro and in vivo studies consistently demonstrates the effects of SIRT7 in modulating angiogenesis, mediated through various molecular mechanisms. Consequently, understanding the regulatory role of SIRT7 in angiogenesis holds significant promise, offering novel avenues for therapeutic interventions targeting either SIRT7 or angiogenesis. This review delineates the putative molecular mechanisms by which SIRT7 regulates angiogenesis, taking its substrates as a clue, endeavoring to elucidate experimental observations by integrating knowledge of SIRT7 substrates and established angiogenenic mechanisms.

3D biological scaffold delivers Bergenin to reduce neuroinflammation in rats with cerebral hemorrhage

BACKGROUND

Intracerebral hemorrhage (ICH) is a severe form of stroke characterized by high incidence and mortality rates. Currently, there is a significant lack of effective treatments aimed at improving clinical outcomes. Our research team has developed a three-dimensional (3D) biological scaffold that incorporates Bergenin, allowing for the sustained release of the compound.

METHODS

This 3D biological scaffold was fabricated using a combination of photoinitiator, GEMA, silk fibroin, and decellularized brain matrix (dECM) to encapsulate Bergenin through advanced 3D bioprinting techniques. The kinetics of drug release were evaluated through both in vivo and in vitro studies. A cerebral hemorrhage model was established, and a 3D biological scaffold containing Bergenin was transplanted in situ. Levels of inflammatory response, oxidative stress, and apoptosis were quantified. The neurological function of rats with cerebral hemorrhage was assessed on days 1, 3, and 5 using the turning test, forelimb placement test, Longa score, and Bederson score.

RESULTS

The 3D biological scaffold incorporating Bergenin significantly enhances the maintenance of drug concentration in the bloodstream, leading to a marked reduction in inflammatory markers such as IL-6, iNOS, and COX-2 levels in a cerebral hemorrhage model, primarily through the inhibition of the NF-κB pathway. Additionally, the scaffold effectively reduces the expression of hypoxia-inducible factor 1-alpha (HIF-1α) in primary cultured astrocytes, which in turn decreases the production of reactive oxygen species (ROS) and inhibits IL-6 production induced by hemin. Subsequent experiments reveal that the 3D biological scaffold containing Bergenin promotes the activation of the Nrf-2/HO-1 signaling pathway, both in vivo and in vitro, thereby preventing cell death. Moreover, the application of this 3D biological scaffold has been demonstrated to improve drug retention in the bloodstream.

CONCLUSION

This strategy effectively mitigates inflammation, oxidative stress, and cell death in rats with cerebral hemorrhage by inhibiting the NF-κB pathway while concurrently activating the Nrf-2/HO-1 pathway.

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

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