Biology subjects

Dostal, C.

Publications and source records attributed to Dostal, C..

4 recordsLinked to original sources

bioRxiv2026

A novel role for Oxaloacetate Decarboxylase FAHD1 in cardiomyocyte maturation

Mitochondrial metabolism undergoes dramatic reprogramming during postnatal cardiac maturation, yet the enzymatic regulators that ensure continuity of TCA cycle flux in this period remain incompletely defined. FAHD1 is a mitochondrial oxaloacetate decarboxylase (ODx) with proposed roles in modulating the activity of Complex II of the electron transport chain (ETC), but its physiological relevance in vivo has remained unclear. Here, we identify FAHD1 as a critical regulator of mitochondrial function with strong impact on cardiomyocyte (CM) maturation. Using a germline Fahd1-knockout (KO) mouse model, we show that Fahd1 deficiency impairs Complex II respiration, reduces pyruvate levels, and induces a compensatory metabolic shift toward glycolysis and anabolic biosynthesis. Loss of FAHD1 disrupts sarcomere organization, delays the fetal-to-adult myosin isoform switch, and leads to left ventricle systolic dysfunction and cardiomyocyte hypertrophy. These findings highlight FAHD1 as a mitochondrial gatekeeper and potential target for modulating cardiac development and disease.

cell biology↗

bioRxiv2026

Cardiac GLP1R gene Expression: A Cross-Species Single-Cell Transcriptomic Analysis

Glucagon-like peptide-1 receptor (GLP1R) agonists improve glycaemic control, induce weight loss, and consistently reduce major adverse cardiovascular events. However, the mechanistic basis of their cardioprotective effects remains incompletely understood, particularly whether benefits arise solely from systemic actions or also involve direct cardiac GLP1R signalling. To address this, we performed integrated single-cell and single-nucleus transcriptomics to map GLP1R gene expression across human and murine organs, cardiac cell types, disease states, and hiPSC-derived cardiac organoids. In humans, GLP1R expression was predominantly pancreatic, with low cardiac expression largely restricted to cardiomyocytes and consistently upregulated across ischaemic, dilated, and hypertrophic cardiomyopathy. In contrast, murine cardiac Glp1r expression was confined to endocardial cells and remained unchanged in heart disease. Other cardiac cell types, including fibroblasts, endothelial cells, and mural cells, showed minimal GLP1R expression in both species. Human cardiac organoids recapitulated ventricular GLP1R patterns closer to adult human myocardium than murine tissue. Together, these findings indicate that GLP1R is primarily extracardiac but selectively induced in failing human myocardium, supporting a model in which myocardial GLP1R signalling augments systemic mechanisms to confer GLP1R agonist-mediated cardioprotection.

bioinformatics↗

bioRxiv2025

CD8+ T cells regulate the bioenergetic reprogramming of lymphoid organs and the heart during viral infection

The activation of the immune system is a bioenergetically-costly process1. Yet, essential bodily functions require a continuous energy supply, imposing energy constraints and trade-offs between competing processes2. Our understanding of the underlying bioenergetic adaptations reconciling rapid immune activation with other vital processes remains scarce. 3-6 Here, by using experimental models of viral infections, we identified an unexpected CD8+ T cell-driven redistribution of energy substrates between lymphoid organs and the heart. Viral infection promoted systemic hypoglycaemia and ketogenesis, together with systemic reallocation of energy substrates. Across organs analysed, secondary lymphoid organs and the heart showed the most dramatic changes. The former increased glucose uptake and oxidation while the heart showed the opposite, switching to preferential fatty acid utilization. These bioenergetic adaptations were absent in infected mice lacking CD8+ T cells or with T cells lacking the glucose transporter GLUT1. Pharmacological inhibition of fatty acid oxidation forced a systemic switch to glucose oxidation. This was associated with metabolic decompensation, reduced cardiac energetics, left ventricular stress, and mortality in otherwise nonlethal viral infections. Our results reveal how the energetic cost of immune cell activation imposes bioenergetic adaptations on non-lymphoid organs, posing a major challenge for the heart by completely relying on fatty acids.

immunology↗

bioRxiv2025

The sodium/glucose cotransporter 2 inhibitor empagliflozin is a pharmacological chaperone of cardiac Nav1.5 channels

Diminished peak sodium current (INa) is a causative factor for slowed ventricular conduction and cardiac arrhythmias in patients with Duchenne muscular dystrophy (DMD), a devastating muscle disease triggered by dystrophin deficiency. Recently, we showed that chronic administration of the sodium/glucose cotransporter 2 (SGLT2) inhibitor empagliflozin (EMPA) restores diminished peak INa in ventricular cardiomyocytes from the dystrophin-deficient mdx mouse model of DMD. Here, we aimed to elucidate the underlying mechanism. Whole cell patch clamp studies revealed that 24 h incubation of dystrophic (mdx) ventricular cardiomyocytes with EMPA significantly increases peak INa in a concentration-dependent manner (EC50=94 nM). The enhancing effect on peak INa also occurred in dystrophic cardiac Purkinje fibers, Nav1.5-expressing tsA201 cells, as well as in dystrophic (DMDmdx) rat cardiomyocytes, and was also exerted by two other SGLT2 inhibitors. Immunofluorescence studies suggested that chronic EMPA treatment increases Nav1.5 plasma membrane expression. Peak INa enhancement by EMPA depended on functional anterograde trafficking of Nav1.5. The local anesthetic mexiletine, a well-known pharmacological chaperone of Nav1.5, enhanced peak INa in a similar manner as EMPA. Further, mutation of human Nav1.5 at a site important for local anesthetic binding (Y1767A) completely abolished the ability of both EMPA and mexiletine to enhance peak INa. Finally, the importance of Y1767 for drug-induced modulation of peak INa was confirmed by molecular docking simulations. Our findings suggest that EMPA acts as a pharmacological chaperone of Nav1.5 channels. Its chronic administration may reduce arrhythmia vulnerability in patients with DMD and other arrhythmogenic pathologies associated with diminished peak INa.

pharmacology and toxicology↗