CTRP13 Protects H9c2 Cells Against Hypoxia/Reoxygenation (H/R)-Induced Injury Via Regulating the AMPK/Nrf2/ARE Signaling Pathway

Navigating the Landscape of Coronary Microvascular Research: Trends, Triumphs, and Challenges Ahead

Coronary microvascular dysfunction (CMD) refers to structural and functional abnormalities of the microcirculation that impair myocardial perfusion. CMD plays a pivotal role in numerous cardiovascular diseases, including myocardial ischemia with non-obstructive coronary arteries, heart failure, and acute coronary syndromes. This review summarizes recent advances in CMD pathophysiology, assessment, and treatment strategies, as well as ongoing challenges and future research directions. Signaling pathways implicated in CMD pathogenesis include adenosine monophosphate-activated protein kinase/Krüppel-like factor 2/endothelial nitric oxide synthase (AMPK/KLF2/eNOS), nuclear factor erythroid 2-related factor 2/antioxidant response element (Nrf2/ARE), Angiotensin II (Ang II), endothelin-1 (ET-1), RhoA/Rho kinase, and insulin signaling. Dysregulation of these pathways leads to endothelial dysfunction, the hallmark of CMD. Treatment strategies aim to reduce myocardial oxygen demand, improve microcirculatory function, and restore endothelial homeostasis through mechanisms including vasodilation, anti-inflammation, and antioxidant effects. Traditional Chinese medicine (TCM) compounds exhibit therapeutic potential through multi-targeted actions. Small molecules and regenerative approaches offer precision therapies. However, challenges remain in translating findings to clinical practice and developing effective pharmacotherapies. Integration of engineering with medicine through microfabrication, tissue engineering and AI presents opportunities to advance the diagnosis, prediction, and treatment of CMD.

Benzoylaconine Protects Skeletal Muscle Against Ischemia-Reperfusion Injury Through Activation of IF1-Dependent AMPK/Nrf2 Axis

Background

Aconitum carmichaelii (Fuzi) has been conventionally used to cure a variety of ailments, such as pain, cold sensations, and numbness of limb muscles (Bi Zheng) in China. Our prior investigations identified Benzoylaconine (BAC) as a bioactive alkaloid derived from Aconitum carmichaelii, with other studies also demonstrating its significant pharmacological potential.

Purpose

This study aimed to explore the potential of BAC as a protective agent against skeletal muscle ischemia-reperfusion (I/R) injury and to elucidate the underlying mechanisms.

Methods

In vivo models involved subjecting Sprague-Dawley rats to I/R through femoral artery ligation followed by reperfusion, while in vitro models utilized C2C12 cells subjected to hypoxia/reoxygenation (H/R). CCK-8 assay was used to assess cell viability. TUNEL staining and flow cytometric analysis were used to measure cell apoptosis. Biochemical assay was used to assess skeletal muscle injury and oxidative stress. Immunofluorescence and Western blot were performed to determine protein levels.

Results

BAC effectively protected muscle tissue from I/R injury, enhancing cell viability (p<0.01), elevating SOD levels (p<0.05), and reducing CK (p<0.01), LDH (p<0.01), ROS (p<0.01), MDA (p<0.01), and apoptosis-related molecules in vivo and in vitro (p<0.05, p<0.01). Mechanistically, BAC increased the expression of IF1, phosphorylated AMPK, facilitated the translocation of nuclear Nrf2, and induced the expression of HO-1 (p<0.01). Notably, AMPK inhibitor Compound C significantly hindered the ability of BAC to ameliorate H/R-induced cell injury (p<0.05), oxidative stress(p<0.01), and apoptosis (p<0.05), as well as promote Nrf2 nuclear translocation (p<0.01). Moreover, silencing of IF1 with siRNA abolished BAC-induced activation of AMPK/Nrf2 axis (p<0.01).

Conclusion

Our study provides novel evidence supporting the potential of BAC as a myocyte-protective agent against I/R injury, and we establish a previously unknown mechanism involving the activation of the IF1-dependent AMPK/Nrf2 axis in mediating the protective effects of BAC.

Potential Targets of Natural Products for Improving Cardiac Ischemic Injury: The Role of Nrf2 Signaling Transduction

Myocardial ischemia is the leading cause of health loss from cardiovascular disease worldwide. Myocardial ischemia and hypoxia during exercise trigger the risk of sudden exercise death which, in severe cases, will further lead to myocardial infarction. The Nrf2 transcription factor is an important antioxidant regulator that is extensively engaged in biological processes such as oxidative stress, inflammatory response, apoptosis, and mitochondrial malfunction. It has a significant role in the prevention and treatment of several cardiovascular illnesses, since it can control not only the expression of several antioxidant genes, but also the target genes of associated pathological processes. Therefore, targeting Nrf2 will have great potential in the treatment of myocardial ischemic injury. Natural products are widely used to treat myocardial ischemic diseases because of their few side effects. A large number of studies have shown that the Nrf2 transcription factor can be used as an important way for natural products to alleviate myocardial ischemia. However, the specific role and related mechanism of Nrf2 in mediating natural products in the treatment of myocardial ischemia is still unclear. Therefore, this review combs the key role and possible mechanism of Nrf2 in myocardial ischemic injury, and emphatically summarizes the significant role of natural products in treating myocardial ischemic symptoms, thus providing a broad foundation for clinical transformation.

CTRP13 alleviates palmitic acid-induced inflammation, oxidative stress, apoptosis and endothelial cell dysfunction in HUVECs

C1q/tumor necrosis factor-related protein 13 (CTRP13) has been reported to participate in cardiovascular diseases. However, the role and molecular mechanism of CTRP13 in obesity-induced endothelial cell damage is still unclear. In palmitic acid (PA)-induced human umbilical vein endothelial cells (HUVECs), qRT-PCR and western blot were used to examine CTRP13 expression. CCK-8 and TUNEL assays were adopted to assess cell viability and apoptosis, respectively. ROS level and MDA content were evaluated by their commercial kits and inflammatory cytokines were measured using ELISA. Endothelial cell dysfunction was evaluated by detecting NO production and eNOS expression, and tube formation assay was performed to assess angiogenesis. AMPK pathway-related proteins were detected by western blot. The results showed that CTRP13 was downregulated in PA-induced HUVECs. CTRP13 overexpression reduced PA-induced cell viability loss and oxidative stress in HUVECs. Moreover, CTRP13 overexpression suppressed PA-induced inflammation and apoptosis, improved angiogenesis ability, and alleviated endothelial cell dysfunction in HUVECs. In addition, CTRP13 overexpression activated AMPK pathway and regulated the expressions of downstream NOX1/p38 and KLF2. Furthermore, compound C countervailed the impacts of CTRP13 overexpression on cell viability, oxidative stress, inflammation, apoptosis and endothelial function in PA-induced HUVECs. To sum up, CTRP13 overexpression may alleviate PA-induced endothelial cell damage.

Pleiotropy of C1QL proteins across physiological systems and their emerging role in synapse homeostasis

The C1q/TNF superfamily of proteins engages in a pleiotropy of physiological functions associated with various diseases. C1QL proteins demonstrate important protective and regulatory roles in the endocrine, immune, cardiovascular, and nervous systems in both human and rodent studies. Studies in the central nervous system (CNS), adipose, and muscle tissue reveal several C1QL protein and receptor pathways altering multiple cellular responses, including cell fusion, morphology, and adhesion. This review examines C1QL proteins across these systems, summarizing functional and disease associations and highlighting cellular responses based on in vitro and in vivo data, receptor interaction partners, and C1QL-associated protein signaling pathways. We highlight the functions of C1QL proteins in organizing CNS synapses, regulating synapse homeostasis, maintaining excitatory synapses, and mediating signaling and trans-synaptic connections. Yet, while these associations are known, present studies provide insufficient insight into the underlying molecular mechanism of their pleiotropy, including specific protein interactions and functional pathways. Thus, we suggest several areas for more in-depth and interdisciplinary hypothesis testing.

Complement 1q/Tumor Necrosis Factor-Related Proteins (CTRPs): Structure, Receptors and Signaling

Adiponectin and the other 15 members of the complement 1q (C1q)/tumor necrosis factor (TNF)-related protein (CTRP) family are secreted proteins composed of an N-terminal variable domain followed by a stalk region and a characteristic C-terminal trimerizing globular C1q (gC1q) domain originally identified in the subunits of the complement protein C1q. We performed a basic PubMed literature search for articles mentioning the various CTRPs or their receptors in the abstract or title. In this narrative review, we briefly summarize the biology of CTRPs and focus then on the structure, receptors and major signaling pathways of CTRPs. Analyses of CTRP knockout mice and CTRP transgenic mice gave overwhelming evidence for the relevance of the anti-inflammatory and insulin-sensitizing effects of CTRPs in autoimmune diseases, obesity, atherosclerosis and cardiac dysfunction. CTRPs form homo- and heterotypic trimers and oligomers which can have different activities. The receptors of some CTRPs are unknown and some receptors are redundantly targeted by several CTRPs. The way in which CTRPs activate their receptors to trigger downstream signaling pathways is largely unknown. CTRPs and their receptors are considered as promising therapeutic targets but their translational usage is still hampered by the limited knowledge of CTRP redundancy and CTRP signal transduction.

C1q/tumor necrosis factor-related protein-6 exerts protective effects on myocardial ischemia-reperfusion injury through the modulation of the Akt-GSK-3β-Nrf2 signaling cascade

C1q/tumor necrosis factor-related protein-6 (CTRP6) is a multifunctional protein that plays a pivotal role in diverse physiological and pathological processes. To date, whether CTRP6 has a role in myocardial ischemia-reperfusion (I/R) injury remains unexplored. This work aimed to investigate the potential role and mechanism of CTRP6 in myocardial I/R injury through in vitro and in vivo experiments. CTRP6 expression was downregulated in hypoxia/reoxygenation (H/R)-treated cardiomyocytes. The apoptosis, oxidative stress, and inflammation in the H/R-treated cardiomyocytes were markedly alleviated by CTRP6 overexpression or exacerbated by CTRP6 silencing. Notably, the overexpression of CTRP6 remarkably ameliorated the myocardial injury, infarction area, cardiac apoptosis, oxidative stress, and inflammation in mice with myocardial I/R injury in vivo. Further investigation revealed that CTRP6 overexpression enhanced the activation of Nrf2 in the H/R-treated cardiomyocytes and the myocardium tissue of mice with myocardial I/R injury. CTRP6 overexpression increased the phosphorylated level of Akt and GSK-3β, and the inhibition of Akt abolished CTRP6-overexpression-elicited Nrf2 activation in the H/R-treated cardiomyocytes. Additionally, the inhibition of Akt or Nrf2 abolished the protective effects of CTRP6 overexpression on the H/R-treated cardiomyocytes. Altogether, CTRP6 had protective effects on myocardial I/R injury via the effects on the Akt-GSK-3β-Nrf2 signaling cascade. Our work recommends CTRP6 as a novel cardioprotective target for the treatment of myocardial I/R injury.

Deciphering mechanism of Zhishi-Xiebai-Guizhi Decoction against hypoxia/reoxygenation injury in cardiomyocytes by cell metabolomics: Regulation of oxidative stress and energy acquisition

Myocardial ischemia/reperfusion (MI/R) injury is a life-threatening syndrome with high morbidity and mortality. Zhishi-Xiebai-Guizhi Decoction (ZSXBGZD) is a classic traditional Chinese medicine formula, used to treat cardiovascular diseases for centuries. However, its underlying medicinal mechanism has not been clearly elucidated, which hinders its widespread application. Here, the curative effects and therapeutic mechanism of ZSXBGZD against MI/R were addressed based on an integration of pharmaceutical evaluation and cellular metabolomics. First, a hypoxia/reoxygenation (H/R) model in H9c2 cells was employed to resemble MI/R and multiple pharmacological indicators were performed to assess the efficacy of ZSXBGZD. The results showed that ZSXBGZD possessed exceptional ability in attenuating cardiomyocyte injury, concerning oxidative stress, mitochondrial dysfunction, energy acquisition and cell apoptosis. Furthermore, a cell metabolomics approach based on HILIC and UPLC-Q-TOF-MS coupled with multivariate analysis was conducted to explore the metabolic regulation of ZSXBGZD. 38 differential polar metabolites related to H/R were uncovered, and 34 of them were reversed to normal state after the treatment of ZSXBGZD, revealing the perturbations of energy metabolism and amino acid metabolism. Moreover, formula decomposition justified the combination of single herbs to form ZSXBZGD and confirmed the pivotal status of Allii Macrostemonis Bulbus and Trichosanthis Fructus.

The initiator of neuroexcitotoxicity and ferroptosis in ischemic stroke: Glutamate accumulation

Glutamate plays an important role in excitotoxicity and ferroptosis. Excitotoxicity occurs through over-stimulation of glutamate receptors, specifically NMDAR, while in the non-receptor-mediated pathway, high glutamate concentrations reduce cystine uptake by inhibiting the System Xc-, leading to intracellular glutathione depletion and resulting in ROS accumulation, which contributes to increased lipid peroxidation, mitochondrial damage, and ultimately ferroptosis. Oxidative stress appears to crosstalk between excitotoxicity and ferroptosis, and it is essential to maintain glutamate homeostasis and inhibit oxidative stress responses in vivo. As researchers work to develop natural compounds to further investigate the complex mechanisms and regulatory functions of ferroptosis and excitotoxicity, new avenues will be available for the effective treatment of ischaemic stroke. Therefore, this paper provides a review of the molecular mechanisms and treatment of glutamate-mediated excitotoxicity and ferroptosis.

Activation of Nrf2 signaling: A key molecular mechanism of protection against cardiovascular diseases by natural products

Cardiovascular diseases (CVD) are a group of cardiac and vascular disorders including myocardial ischemia, congenital heart disease, heart failure, hypertension, atherosclerosis, peripheral artery disease, rheumatic heart disease, and cardiomyopathies. Despite considerable progress in prophylaxis and treatment options, CVDs remain a leading cause of morbidity and mortality and impose an extremely high socioeconomic burden. Oxidative stress (OS) caused by disequilibrium in the generation of reactive oxygen species plays a crucial role in the pathophysiology of CVDs. Nuclear erythroid 2-related factor 2 (Nrf2), a transcription factor of endogenous antioxidant defense systems against OS, is considered an ideal therapeutic target for management of CVDs. Increasingly, natural products have emerged as a potential source of Nrf2 activators with cardioprotective properties and may therefore provide a novel therapeutic tool for CVD. Here, we present an updated comprehensive summary of naturally occurring products with cardioprotective properties that exert their effects by suppression of OS through activation of Nrf2 signaling, with the aim of providing useful insights for the development of therapeutic strategies exploiting natural products.

Paeoniflorin Protects H9c2 Cardiomyocytes against Hypoxia/Reoxygenation Induced Injury via Regulating the AMPK/Nrf2 Signaling Pathway

Myocardial ischemia/reperfusion (MIR) injury contributes to the exacerbation of heart disease by causing cardiac arrhythmias, myocardial infarction, and even sudden death. Studies have found that paeoniflorin (PF) has a protective effect on coronary artery disease (CAD). However, the mechanism of PF in MIR has not been fully investigated. The purpose of this study was to investigate the functional role of PF in H9c2 cells subjected to hypoxia/reoxygenation (H/R). Here, PF treatment enhanced cell viability in H/R-stimulated H9c2 cells. In H9c2 cells, PF treatment reduced the formation of reactive oxygen species (ROS) induced by H/R. In H/R-stimulated H9c2 cells, PF also increased the activity of antioxidant enzymes such as superoxide dismutase and glutathione peroxidase. Furthermore, PF protected H9c2 cells against H/R-induced apoptosis, as demonstrated by increased Bcl-2 expression, decreased Bax expression, and decreased caspase-3 activity. Furthermore, PF increased the levels of p-AMPK and nuclear Nrf2 expression in response to H/R stimulation. AMPK inhibition, on the other hand, abolished the PF-mediated increase in Nrf2 signaling and the cardiac-protective effect in H9c2 cells exposed to H/R. These data suggest that PF protected H9c2 cells against H/R-induced oxidative stress and apoptosis through modulating the AMPK/Nrf2 signaling pathway. Our findings support the therapeutic potential of PF in myocardial I/R damage.

Targeting Nrf2 in ischemia-reperfusion alleviation: From signaling networks to therapeutic targeting

The nuclear factor erythroid 2-related factor 2 (Nrf2) is a master regulator of redox balance and it responds to various cell stresses that oxidative stress is the most well-known one. The Nrf2 should undergo nuclear translocation to exert its protective impacts and decrease ROS production. On the other hand, ischemic/reperfusion (I/R) injury is a pathological event resulting from low blood flow to an organ and followed by reperfusion. The I/R induces cell injury and organ dysfunction. The present review focuses on Nrf2 function in alleviation of I/R injury. Stimulating of Nrf2 signaling ameliorates I/R injury in various organs including lung, liver, brain, testis and heart. The Nrf2 enhances activity of antioxidant enzymes to reduce ROS production and prevent oxidative stress-mediated cell death. Besides, Nrf2 reduces inflammation via decreasing levels of pro-inflammatory factors including IL-6, IL-1β and TNF-α. Nrf2 signaling is beneficial in preventing apoptosis and increasing cell viability. Nrf2 induces autophagy to prevent apoptosis during I/R injury. Furthermore, it can interact with other molecular pathways including PI3K/Akt, NF-κB, miRNAs, lncRNAs and GSK-3β among others, to ameliorate I/R injury. The therapeutic agents, most of them are phytochemicals such as resveratrol, berberine and curcumin, induce Nrf2 signaling in I/R injury alleviation.

Programmed Cell Death: Complex Regulatory Networks in Cardiovascular Disease

Abnormalities in programmed cell death (PCD) signaling cascades can be observed in the development and progression of various cardiovascular diseases, such as apoptosis, necrosis, pyroptosis, ferroptosis, and cell death associated with autophagy. Aberrant activation of PCD pathways is a common feature leading to excessive cardiac remodeling and heart failure, involved in the pathogenesis of various cardiovascular diseases. Conversely, timely activation of PCD remodels cardiac structure and function after injury in a spatially or temporally restricted manner and corrects cardiac development similarly. As many cardiovascular diseases exhibit abnormalities in PCD pathways, drugs that can inhibit or modulate PCD may be critical in future therapeutic strategies. In this review, we briefly describe the process of various types of PCD and their roles in the occurrence and development of cardiovascular diseases. We also discuss the interplay between different cell death signaling cascades and summarize pharmaceutical agents targeting key players in cell death signaling pathways that have progressed to clinical trials. Ultimately a better understanding of PCD involved in cardiovascular diseases may lead to new avenues for therapy.