Kar, Riya

Myocardial infarction (MI) remains a leading cause of mortality worldwide, yet effective cardioprotective strategies remain limited in clinical settings. Vascular endothelial growth factor B (VEGFB) has emerged as a promising therapeutic candidate in MI, but the role of its co-receptor, Neuropilin-1 (NRP1), in cardiomyocyte (CM) survival under ischemic stress remains poorly understood. Here, we investigated VEGFB-NRP1 signaling using an in vivo zebrafish model of cardiac injury as well as in vitro hypoxia models in CMs. We demonstrated that VEGFB overexpression conferred protection against ischemic injury and enhanced cardiac regeneration in the zebrafish heart. Mechanistically, we showed that VEGFB treatment enhances CM viability through reducing reactive oxygen species (ROS), ferroptosis activation, and preserving mitochondrial integrity. We also demonstrated that NRP1 knockdown in the CMs abolished the VEGFB-mediated protective effects, indicating the significant role of NRP1 signaling in VEGFB-induced cardioprotective effects in MI. Lastly, using transcriptome analysis, we confirmed that VEGFB induces anti-apoptotic and anti-ferroptosis gene programs in CMs in response to hypoxic stress. Collectively, our findings provide mechanistic insight into cell death activation pathways, including ferroptosis, in response to ischemic stress and further validate the therapeutic potential of VEGFB in promoting CM survival in ischemic heart disease.

Abstract Background Myocardial infarction (MI) remains a leading cause of mortality worldwide. Recent studies suggest a cardioprotective role for vascular endothelial growth factor-B (VEGF-B) in MI. However, the molecular mechanisms of VEGF-B-mediated signaling via its co-receptor Neuropilin-1 (NRP1) in MI are poorly understood. In this study, we investigated the intricate signaling mechanisms involving VEGF-B and NRP1 in cardiomyocytes (CMs) using ischemic injury as a model of MI. And secondly, we further validated the protective role of VEFG-B in ischemic heart disease, shedding light on their roles not only in cardiac function but also in its therapeutic potential. Methods In this study, we utilized both in vitro and in vivo approaches to elucidate the role of VEGF-B and NRP1 signaling in MI and how it manifests a protective role in mitochondrial functions and cardiac regeneration following ischemic injury. We used two different cardiomyocyte cell lines, H9c2 (rat ventricular cardiomyocytes) and HL-1 (mouse ventricular cardiomyocytes), and induced hypoxia conditions, using either 1% oxygen or 200µM cobalt chloride (CoCl 2 ) to mimic the myocardial infarction-induced ischemic injury in the heart. In addition, we developed a novel heat shock inducible zebrafish model of a cardiomyocyte-specific VEGF-B overexpression system to further examine the protective role of VEGF-B in vivo . Results Our findings indicate that both VEGF-B and NRP1 are predominantly expressed in heart tissue compared to other tissues, and their expression is altered in response to hypoxia/ischemic injury. Our results demonstrate that VEGF-B treatment prior to hypoxia enhances cardiomyocyte survival, while NRP1 knockdown abolishes this protective effect, highlighting a prominent role of NRP1 signaling in VEGF-B-mediated cardio protection. Furthermore, we found that VEGF-B promotes cardiomyocyte survival by improving mitochondrial function, as evidenced by reduced oxidative stress and ROS accumulation, decreased oxidative stress, preserved mitochondrial membrane potential, and increased ATP levels. Lastly, using our VEGF-B transgenic zebrafish model, we demonstrated that VEGF-B overexpression in zebrafish cardiomyocytes protects the heart from ischemic injury and enhances cardiac regeneration in an NRP1-dependent manner. Conclusion Our study has uncovered an important role of VEGF-B-NRP1 signaling axis in VEGF-B mediated cell survival and in beneficial mitochondrial functions in the CMs. Importantly, we also demonstrated that VEGF-B is protective against ischemic injury in vivo using a novel zebrafish model Novelty and Significance What Is Known? Myocardial infarction (MI) results in mitochondrial dysfunction, cardiomyocyte death, and adverse ventricular remodeling. Vascular Endothelial Growth Factor B (VEGF-B) is traditionally associated with cardiac metabolism, survival, vascular biology, particularly in angiogenesis and lipid metabolism. The neurophilin-1 (NRP1) receptor, a co-receptor for VEGF-B, is expressed in cardiomyocytes and implicated in mitochondrial signaling pathways. Emerging evidence suggests that VEGF-B may influence mitochondrial integrity and function under stress conditions. What New Information Does This Article Contribute? VEGF-B exerts a protective effect on cardiomyocyte mitocondria following ischemic injury by preserving mitochondrial function and reducing oxidative stress. NRP1 receptor as a key mediator of VEGF-B modulates mitochondrial homeostasis in cardiomyocytes. VEGF-B signaling can attenuate apoptosis and enhance mitochondrial bioenergetics post-MI, suggesting a novel cardioprotective mechanism. Clinical Implication: These findings suggest that therapeutic strategies aimed at enhancing VEGF-B/NRP1 signaling may improve mitochondrial function and cardiac recovery after MI, offering a novel avenue for limiting heart failure progression in ischemic heart disease.

Recent advancements in disease modeling for myocardial infarction (MI) and coronary artery disease (CAD) have significantly enhanced our understanding of cardiovascular pathology and therapeutic development. This review comprehensively reviews the integration of in vivo and in vitro approaches to better model and study these conditions. We specifically focus on cutting-edge in vitro techniques, such as cardiac organoids, engineered heart tissues, and patient-derived induced pluripotent stem cells (iPSCs), which allow for detailed exploration of cellular and molecular mechanisms involved in MI and CAD. These models provide insights into ischemic injury, myocardial remodeling, and the effects of potential therapeutic interventions at a cellular level. In parallel, we discuss advances in the in vivo models, including genetically modified mice and large animal models, which offer valuable information on disease progression, cardiac function, and response to treatments within a more complex physiological context. By bridging these in vivo and in vitro approaches, researchers can gain a more comprehensive understanding of disease mechanisms, validate experimental findings, and accelerate the development of effective therapies. This review highlights recent progress, identifies current limitations, and proposes strategies for future research to enhance the translation of model-based discoveries into clinical practice for MI and CAD.