Hypoxia-inducible factor-1: Regulatory mechanisms and drug therapy in myocardial infarction

Impairing Ferroptosis Through the PI3K/Akt/Nrf2 Pathway: The Way for Nerve Growth Factor to Mitigate Hypoxia-induced Cardiomyocyte Damage

Myocardial infarction (MI) is an acute cardiovascular diseases, distinguished primarily by cardiomyocyte damage due to ischemia and hypoxia. Nerve growth factor (NGF) is paramount in ischemic heart disease, it contributes to maintaining heart function and protecting the heart. Nonetheless, the effects of NGF on cardiomyocyte damage induced by hypoxia and the precise mechanisms involved are still to be elucidated. Utilizing western blot and immunofluorescence methods to quantify the NGF levels in cardiomyocytes (H9C2) of rats after hypoxia. Cell Counting Kit-8 (CCK-8) assay was employed to monitor the dynamic changes in cells vitality. The lactate dehydrogenase (LDH), Fe2+, malondialdehyde (MDA), superoxide dismutase (SOD) and reactive oxygen species (ROS) levels were evaluated by different kits. Moreover, the PI3K/Akt/Nrf2 pathway and ferroptosis-linked protein levels were analyzed using western blotting. In H9C2 cells, exposure to hypoxia for 24 h led to weakened NGF level, as well as lowered cell vitality and SOD activity, but elevated levels of LDH, Fe2+, MDA, and ROS, triggering ferroptosis. Overexpression NGF alleviated the ferroptosis in H9C2 cells caused by hypoxia, while NGF knockdown intensified this process. Additionally, overexpression NGF reinforced heme oxygenase-1 (HO-1) and Nrf2 levels, and Akt and PI3K phosphorylation, whereas NGF silencing produced contrary outcomes. Furthermore, the PI3K/Akt pathway inhibitor negated the elevation in HO-1 and Nrf2 levels mediated by NGF amplification. In contrast, the pathway activator reversed the lowering in Nrf2 and HO-1 levels caused by silencing NGF. This suggested that NGF mediates the activation of Nrf2 through the PI3K/Akt axis. Overall, by mediating the activation of Nrf2 through the PI3K/Akt axis, NGF reduced the damage to H9C2 cells caused by hypoxia and thus hindered ferroptosis.

Biological function of RNA-binding proteins in myocardial infarction: a potential emerging therapeutic limelight

Myocardial infarction (MI) is currently one of the most fatal cardiovascular diseases worldwide. The screening, treatment, and prognosis of MI are top priorities for cardiovascular centers globally due to its characteristic occult onset, high lethality, and poor prognosis. MI is caused by coronary artery occlusion induced by coronary atherosclerotic plaque blockage or other factors, leading to ischemic necrosis and apoptosis of cardiomyocytes. Although significant advancements have been made in the study of cardiomyocytes at the cellular and molecular levels, RNA-binding proteins (RBPs) have not been extensively explored in the context of MI. RBPs, as key regulators coordinating cell differentiation and tissue homeostasis, exhibit specific functions in gene transcription, RNA modification and processing, and post-transcriptional gene expression. By binding to their target RNA, RBPs coordinate various RNA dynamics, including cellular metabolism, subcellular localization, and translation efficiency, thereby controlling the expression of encoded proteins. Classical RBPs, including HuR, hnRNPs, and RBM family molecules, have been identified as critical regulators in myocardial hypoxia, oxidative stress, pro-inflammatory responses, and fibrotic repair. These RBPs exert their effects by modulating key pathophysiological pathways in MI, thereby influencing specific cardiac outcomes. Additionally, specific RBPs, such as QKI and fused in sarcoma (FUS), are implicated in the apoptotic pathways activated during MI. This apoptotic pathway represents a significant molecular phenotype in MI, offering novel perspectives and insights for mitigating cardiomyocyte apoptosis and attenuating the progression of MI. Therefore, this review systematically summarizes the role of RBPs in the main pathophysiological stages of MI and explores their potential therapeutic prospects.

A Study on the Levels of Selected Proangiogenic Proteins in Human Tissues and Plasma in Relation to Brain Glioma

Brain glioma is one of the most common malignant tumors of brain tissue. It is characterized by rich vascularization, which indicates the significant participation of angiogenesis in its growth and development. In its first stages, the disease is very often asymptomatic, and late diagnosis significantly limits possibilities of treatment. Tumor angiogenesis, i.e., the formation of new vessels, requires the presence of angiogenic compounds that will enable tumor progression by creating a path for the supply of nutrients. The proangiogenic compounds involved in the development of glioma include hypoxia-inducible factor 1α (HIF-1α), angiopoietin-2 (ANG-2), and interleukin-1β (IL-1β). The aim of this study was to analyze changes in the levels of these proteins in plasma samples of patients diagnosed with brain glioma in stages G1 to G4, and in a control group, using SPRi biosensors. The results obtained in plasma were compared with the concentrations obtained during the analysis of tissue homogenates from patients with glioma in stages G2 to G4. A statistically significant difference in plasma concentrations was obtained between the patient group and the control group. The concentrations of the markers in tissue homogenate samples were statistically higher than in blood plasma. There was no significant effect of gender, diet, smoking, or the patient's general health condition (Karnofsky score) on the course of the disease. These factors do not directly increase the risk of developing brain glioma.

Untargeted metabolomics combined with lipidomics revealed the effects of myocardial infarction and exercise rehabilitation on blood circulation metabolism of patients based on liquid chromatography-mass spectrometry

Myocardial infarction (MI) is a major cause of death worldwide. Exercise rehabilitation (ER) is a powerful tool to improve life quality and prognosis of MI patients. Herein, we developed an untargeted metabolomics combined with lipidomics method to qualitatively and quantitatively detect metabolites in plasma. A total of 475 metabolites were annotated according to MS, MS/MS, and quantified by internal standard method. Moreover, medical statistical methods combined with chemometrics were used for metabolomics data mining and interpretation of clinical issues (matched Cohort 1, n = 90, Cohort 2, n = 6). The results illustrated that abnormal lipid metabolism is the most significant metabolic disorder for MI patients. And, three metabolic pathways, bile secretion, HIF-1 signaling pathway, and glutathione metabolism were uncovered in MI patients. Furthermore, glutamine, Phenylacetylglutamine (PAGln) and lysophosphatidylcholine (LPCs) were revealed as the essential biomarkers for ER of MI patients. Our findings revealed the metabolic landscape of MI and metabolic alterations after ER, will underlay potential applications of plasma metabolites in the detection of MI and optimization of ER program.

Systematic and comprehensive insights into HIF-1 stabilization under normoxic conditions: implications for cellular adaptation and therapeutic strategies in cancer

Hypoxia-inducible factors (HIFs) are essential transcription factors that orchestrate cellular responses to oxygen deprivation. HIF-1α, as an unstable subunit of HIF-1, is usually hydroxylated by prolyl hydroxylase domain enzymes under normoxic conditions, leading to ubiquitination and proteasomal degradation, thereby keeping low levels. Instead of hypoxia, sometimes even in normoxia, HIF-1α translocates into the nucleus, dimerizes with HIF-1β to generate HIF-1, and then activates genes involved in adaptive responses such as angiogenesis, metabolic reprogramming, and cellular survival, which presents new challenges and insights into its role in cellular processes. Thus, the review delves into the mechanisms by which HIF-1 maintains its stability under normoxia including but not limited to giving insights into transcriptional, translational, as well as posttranslational regulation to underscore the pivotal role of HIF-1 in cellular adaptation and malignancy. Moreover, HIF-1 is extensively involved in cancer and cardiovascular diseases and potentially serves as a bridge between them. An overview of HIF-1-related drugs that are approved or in clinical trials is summarized, highlighting their potential capacity for targeting HIF-1 in cancer and cardiovascular toxicity related to cancer treatment. The review provides a comprehensive insight into HIF-1's regulatory mechanism and paves the way for future research and therapeutic development.

Prolonged Hypoxia in Rat Living Myocardial Slices Affects Function, Expression, and Structure

Ischemic heart disease is the leading cause of death worldwide. Reduced oxygen supply and myocardial hypoxia lead to tissue damage and impairment of the heart function. To the best of our knowledge, the primary functional effects of hypoxia in the multicellular model of living myocardial slices (LMSs) have not been investigated so far. In this study, we analyzed force generation, ultrastructure, gene expression, and proteome changes in rat LMS after 24 h of ex vivo culture in normal and reduced levels of oxygen (O2). We observed a significant reduction in absolute force and a slowdown of force kinetics as well as an increase in cardiomyocyte apoptosis and myofibrillar and mitochondrial damage, as well as transcriptomic changes. Proteome analysis revealed the deregulation of proteins involved in metabolic processes, hypoxic response, and neutralizing of reactive oxygen species. Our results indicate that hypoxia induces substantial primary changes in heart tissue, which are independent of perfusion and immune responses. Our new LMS model could serve as a screening system for drug development and new mechanistic insights.

Regulation of transcription factor function by purinergic signalling in cardiovascular diseases

Cardiovascular diseases (CVDs), including hypertension, atherosclerosis, myocardial ischemia, and myocardial infarction, constitute the primary cause of mortality worldwide. Transcription factors play critical roles in the development of CVDs and contribute to the pathophysiology of these diseases by coordinating the transcription of many genes involved in inflammation, oxidative stress, angiogenesis, and glycolytic metabolism. One important regulator of hemostasis in both healthy and pathological settings has been identified as a purinergic signalling pathway. Research has demonstrated that several signalling networks implicated in the pathophysiology of CVDs are formed by transcription factors that are regulated by purinergic substances. Here, we briefly summarize the roles and mechanisms of the transcription factors regulated by purinergic pathways in various types of CVD. This information will be essential for discovering novel approaches for CVD treatment and prevention.

Preparation of antioxidant peptides from yak skin gelatin and their protective effect on myocardial ischemia reperfusion injury

We herein report a study on the antioxidant peptides that show potential in alleviating myocardial ischemia reperfusion injury (MI/RI). Yak skin gelatin fraction Ac (YSG-Ac), obtained through ultrafiltration and gel filtration with Sephadex G-15, exhibits a favorable nutrient composition, high foaming capacity and stability, and resistance against gastrointestinal digestion. LC-MS/MS analysis reveals that YSG-Ac contains 26 peptide segments with sequence lengths of 8 to 12 amino acids. Online screening suggests that the antioxidant capacity of YSG-Ac is mainly attributed to the presence of hydrophobic and antioxidant amino acids. In vitro, our results demonstrate the MI/RI protective effects of YSG-Ac by effectively repairing H2O2-induced oxidative damage in H9c2 cells, which is achieved by inhibiting malondialdehyde (MDA) levels, and increasing glutathione peroxidase (GSH-pX) and superoxide dismutase (SOD) activity. In vivo, our results further confirm the effectiveness of YSG-Ac in narrowing the area of myocardial infarction, decreasing MDA levels, increasing SOD activity, and reducing the content of lactate dehydrogenase (LDH) in a mouse MI/RI model. Molecular docking analysis indicates that PGADGQPGAK with xanthine dehydrogenase (XDH) and GAAGPTGPIGS with tumor necrosis factor-alpha (TNF-α) exhibit strong bonding capability, and other related targets also show certain binding ability toward YSG-Ac. This suggests that YSG-Ac can regulate MI/RI through multiple targets and pathways. Overall, our findings highlight the potential of YSG-Ac as a functional food ingredient with antioxidant and MI/RI protective characteristics.

The Janus face of HIF-1α in ischemic stroke and the possible associated pathways

Stroke is the most devastating disease, causing paralysis and eventually death. Many clinical and experimental trials have been done in search of a new safe and efficient medicine; nevertheless, scientists have yet to discover successful remedies that are also free of adverse effects. This is owing to the variability in intensity, localization, medication routes, and each patient's immune system reaction. HIF-1α represents the modern tool employed to treat stroke diseases due to its functions: downstream genes such as glucose metabolism, angiogenesis, erythropoiesis, and cell survival. Its role can be achieved via two downstream EPO and VEGF strongly related to apoptosis and antioxidant processes. Recently, scientists paid more attention to drugs dealing with the HIF-1 pathway. This review focuses on medicines used for ischemia treatment and their potential HIF-1α pathways. Furthermore, we discussed the interaction between HIF-1α and other biological pathways such as oxidative stress; however, a spotlight has been focused on certain potential signalling contributed to the HIF-1α pathway. HIF-1α is an essential regulator of oxygen balance within cells which affects and controls the expression of thousands of genes related to sustaining homeostasis as oxygen levels fluctuate. HIF-1α's role in ischemic stroke strongly depends on the duration and severity of brain damage after onset. HIF-1α remains difficult to investigate, particularly in ischemic stroke, due to alterations in the acute and chronic phases of the disease, as well as discrepancies between the penumbra and ischemic core. This review emphasizes these contrasts and analyzes the future of this intriguing and demanding field.