Metabolite signaling in the heart

Molecular Regulation of Cardiomyocyte Maturation

PURPOSE OF THE REVIEW

This review aims to discuss the process of cardiomyocyte maturation, with a focus on the underlying molecular mechanisms required to form a fully functional heart. We examine both long-standing concepts associated with cardiac maturation and recent developments, and the overall complexity of molecularly integrating all the processes that lead to a mature heart.

RECENT FINDINGS

Cardiac maturation, defined here as the sequential changes that occurring before the heart reaches full maturity, has been a subject of investigation for decades. Recently, there has been a renewed, highly focused interest in this process, driven by clinically motivated research areas where enhancing maturation may lead to improved therapeutic opportunities. These include using pluripotent stem cell models for cell therapy and disease modeling, as well as recent advancements in adult cardiac regeneration approaches. We highlight key processes underlying maturation of the heart, including cellular and organ growth, and electrophysiological, metabolic, and contractile maturation. We further discuss how these processes integrate and interact to contribute to the overall complexity of the developing heart. Finally, we emphasize the transformative potential for translating relevant maturation concepts to emerging models of heart disease and regeneration.

Liver metabolism in human MASLD: A review of recent advancements using human tissue metabolomics

Global incidence of Metabolic dysfunction-Associated Steatotic Liver Disease (MASLD) is on the rise while treatments remain elusive. MASLD is a disease of dysregulated systemic and hepatic metabolism. Current understanding of disease pathophysiology as it relates to metabolome changes largely comes from studies on animal models and human plasma. However, human tissue data are crucial for transitioning from mechanisms to clinical therapies. The close relationship between MASLD and comorbidities like obesity, type 2 diabetes and dyslipidemia make it difficult to determine the contribution from liver disease itself. Here, we review recent metabolomics studies in liver tissue from human MASLD patients, which have predominately focused on lipid metabolism, but also include bile acid, tricarboxylic acid (TCA) cycle, and branched chain amino acid (BCAA) metabolism. Several clinical trials are underway to target various of these lipid-related pathways in MASLD. Although only the β-selective thyroid hormone receptor agonist resmetirom has so far been approved for use, many metabolism-targeting pharmaceuticals show promising results for halting disease progression, if not promoting outright reversal. Ultimately, the scarcity of human tissue data and the variability of confounding factors, like obesity, within and between cohorts are impediments to the pathophysiological understanding required for efficient development of metabolic treatments.

Reference-Attached pH Nanosensor for Accurately Monitoring the Rapid Kinetics of Intracellular H+ Oscillations

Intracellular pH (pHi) is an essential indicator of cellular metabolic activity, as its transient or small shift can significantly impact cellular homeostasis and reflect the cellular events. Real-time and precise tracking of these rapid pH changes within a single living cell is therefore important. However, achieving high dynamic response performance (subsecond) pH detection inside a living cell with high accuracy remains a challenge. Here a reference-attached pH nanosensor (R-pH-nanosensor) with fast and precise pHi sensing performance is introduced. The nanosensor comprises a highly conductive H+-sensitive IrRuOx nanowire (SiC@IrRuOx NW) as the intracellular working electrode and a SiC@Ag/AgCl NW as an intracellular reference electrode (RE) to diminish the interferences arising from cell membrane potential fluctuations. This whole-inside-cell detection mode ensures that the entire potential detection circuit is located within the same cell, and the R-pH-nanosensor is able to quantify the mild acidification of cytosol and completely record the fast pH variation within a single cell. It also enables real-time potentiometric monitoring of the pHi oscillations, which synchronize with the glycolysis oscillations in cancer cells. Furthermore, the asymmetry in glycolysis oscillations wave is disclosed and the inhibitory effect of just lactate to glycolysis oscillations is further confirmed.

Intersection of Immunology and Metabolism in Myocardial Disease

Immunometabolism is an emerging field at the intersection of immunology and metabolism. Immune cell activation plays a critical role in the pathogenesis of cardiovascular diseases and is integral for regeneration during cardiac injury. We currently possess a limited understanding of the processes governing metabolic interactions between immune cells and cardiomyocytes. The impact of this intercellular crosstalk can manifest as alterations to the steady state flux of metabolites and impact cardiac contractile function. Although much of our knowledge is derived from acute inflammatory response, recent work emphasizes heterogeneity and flexibility in metabolism between cardiomyocytes and immune cells during pathological states, including ischemic, cardiometabolic, and cancer-associated disease. Metabolic adaptation is crucial because it influences immune cell activation, cytokine release, and potential therapeutic vulnerabilities. This review describes current concepts about immunometabolic regulation in the heart, focusing on intercellular crosstalk and intrinsic factors driving cellular regulation. We discuss experimental approaches to measure the cardio-immunologic crosstalk, which are necessary to uncover unknown mechanisms underlying the immune and cardiac interface. Deeper insight into these axes holds promise for therapeutic strategies that optimize cardioimmunology crosstalk for cardiac health.

Mitochondrial heterogeneity and adaptations to cellular needs

Although it is well described that mitochondria are at the epicentre of the energy demands of a cell, it is becoming important to consider how each cell tailors its mitochondrial composition and functions to suit its particular needs beyond ATP production. Here we provide insight into mitochondrial heterogeneity throughout development as well as in tissues with specific energy demands and discuss how mitochondrial malleability contributes to cell fate determination and tissue remodelling.

Ferroptosis-Regulated Cell Death as a Therapeutic Strategy for Neurodegenerative Diseases: Current Status and Future Prospects

Ferroptosis is increasingly being recognized as a key element in the pathogenesis of diverse diseases. Recent studies have highlighted the intricate links between iron metabolism and neurodegenerative disorders. Emerging evidence suggests that iron homeostasis, oxidative stress, and neuroinflammation all contribute to the regulation of both ferroptosis and neuronal health. However, the precise molecular mechanisms underlying the involvement of ferroptosis in the pathological processes of neurodegeneration and its impact on neuronal dysfunction remain incompletely understood. In our Review, we provide a comprehensive analysis and summary of the potential molecular mechanisms underlying ferroptosis in neurodegenerative diseases, aiming to elucidate the disease progression of neurodegeneration. Additionally, we discuss potential therapeutic agents that modulate ferroptosis with the goal of identifying novel drug molecules for the treatment of neurodegenerative disorders.