Harbuzariu, A. | bioRxiv Science

bioRxiv2026

Cardiomyocyte-intrinsic SLC25A1 regulates cardiac differentiation and mitochondrial function

Cardiac morphogenesis is an intricate process that requires a precise coordination between metabolic and structural maturation, but how these processes are linked remain unclear. In previous work, we identified one candidate underlying this connection: the mitochondrial citrate carrier (SLC25A1), a critical regulator of embryonic heart development. Here, using systemic and cardiomyocyte-specific Slc25a1 deletion in mice together with SLC25A1 knockout (KO) human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs), we demonstrate that SLC25A1 functions cell-autonomously within cardiomyocytes to regulate differentiation, mitochondrial maturation, and ventricular morphogenesis. Transcriptomic analysis of SLC25A1-deficient hearts revealed dysregulation of gene programs regulating cardiomyocyte differentiation and mitochondrial function. Consistent with these changes, loss of SLC25A1 in developing cardiomyocytes impaired mitochondrial function and resulted in defective ventricular wall compaction in vivo. Likewise, SLC25A1 KO hiPSC-CMs exhibited defective cardiomyocyte differentiation, disorganized myofibrils, and immature mitochondrial organization and function in vitro. Together, our findings position SLC25A1 as a cardiomyocyte-intrinsic, cell-autonomous regulator that links mitochondrial citrate export to developmental gene programs, revealing a mitochondrial regulatory axis for cardiomyocyte maturation and cardiac morphogenesis that contributes to congenital heart disease.

developmental biology↗

bioRxiv2025

Mitochondrially Transcribed dsRNA Mediates Manganese-induced Neuroinflammation

Manganese is an essential trace element required for various biological functions, but in excess is neurotoxic and leads to significant health concerns. The mechanisms underlying manganese neurotoxicity remain poorly understood. Neuropathological studies of affected brain regions reveal astrogliosis, neuronal loss, and neuroinflammation. Here, we present a novel manganese-dependent mechanism linking mitochondrial dysfunction to neuroinflammation. We found that manganese disruption of the mitochondrial transcriptome processing results in the accumulation of double stranded RNA (dsRNA). This dsRNA is released into the cytoplasm, where it activates the cytosolic sensor MDA5, triggering type I interferon responses and inflammatory cytokine production. This mechanism is evident in 100 day human cerebral organoids, where manganese-increased mitochondrial dsRNA and induced inflammatory responses in mature astrocytes. Similarly, we observed an increase in mitochondrial dsRNA content, the activation of an inflammatory transcriptome and the production of cytokines in female and male mouse brains carrying mutations in the Slc30a10 gene, a model for human hypermanganesemia with dystonia 1 disorder. These findings highlight a previously unrecognized role for mitochondrial dsRNA in manganese-induced neuroinflammation and provide insights into the molecular pathogenesis of manganism. We propose that this mitochondrial dsRNA-induced inflammatory pathway could be active in other neurological diseases caused by environmental or genetic factors. Significance StatementEnvironmental exposures and genetic defects that perturb manganese homeostasis are an underappreciated cause of neurodegeneration and neuroinflammation. We describe a new paradigm for inducible neuroinflammation, where manganese disruption of mitochondrial transcriptome processing leads to the accumulation of mitochondrial double-stranded RNA (dsRNA), which activate antiviral responses in the cytoplasm driving type I interferon dependent inflammation. This manganese-dsRNA axis is induced in cell lines in vitro and a subpopulation of mature astrocytes in exposed human cerebral organoids. Brain cortex of mice deficient in the manganese efflux transporter Slc30a10, a genetic model of chronic manganese accumulation, show dsRNA accumulation, and up-regulation of type I interferon response and astrogliosis markers, supporting a role for this pathway in neurotoxicity and parkinsonism.

neuroscience↗