Birge, R. | Search bioRxiv

bioRxiv2026

Cardiomyocyte-derived Wnt5a drives doxorubicin-induced cardiomyopathy by amplifying cellular senescence

Doxorubicin (DOX) is an effective anthracycline chemotherapeutic agent, but its use is limited by cardiotoxicity that can progress to cardiomyopathy and heart failure. Cellular senescence contributes to DOX-induced cardiac injury, yet the upstream signals that initiate and propagate senescence in the injured heart remain unclear. Here, we identify Wnt5a, a non-canonical Wnt ligand, as a mediator of anthracycline cardiomyopathy. WNT5A was increased in serum from cancer patients receiving anthracycline therapy and in a pathologic human cardiomyocyte population in the context of DOX-induced cardiomyopathy. In mouse hearts, DOX induced early cardiomyocyte-enriched Wnt5a expression before overt cardiac dysfunction. Cardiomyocyte-specific Wnt5a deletion attenuated DOX-induced cardiac dysfunction, fibrosis and senescence marker induction, whereas recombinant Wnt5a and cardiomyocyte-targeted Wnt5a overexpression were sufficient to promote cardiomyocyte senescence and cardiac dysfunction. Mechanistically, DOX activated a Wnt5a-Fzd2 feed-forward axis that amplified Wnt5a expression in cardiomyocytes and propagated senescence to neighboring fibroblasts. Genetic disruption of this pathway in cardiomyocytes, fibroblasts or senescent cells reduced DOX-induced cardiomyopathy. Pharmacological inhibition of Wnt5a signaling with secreted frizzled-related protein 5 suppressed DOX-induced cardiac injury without compromising the anticancer efficacy of DOX. These findings identify Wnt5a-Fzd2 signaling as a senescence-amplifying mechanism in anthracycline cardiomyopathy and suggest a therapeutic strategy to mitigate DOX cardiotoxicity.

cell biology↗

bioRxiv2026

Lipid Flippase Mediated Membrane Asymmetry Governs Extracellular Vesicles Biogenesis and Host Interactions in Cryptococcus neoformans

Cryptococcus neoformans is the leading cause of fungal meningitis in immunocompromised patients. Alveolar macrophages are the first line of defense against Cryptococcus infection. Our previous study showed that deletion of Cdc50, the regulatory subunit of P4-ATPase (lipid flippase) complex, results in increased phagocytosis and macrophage killing, and avirulence in animal models. However, how fungal flippase dysfunction modulates Cryptococcus-macrophage interaction remains unknown. Here we identify Cdc50 as a central determinant of membrane lipid homeostasis, extracellular vesicle (EV) biogenesis and macrophage responses in C. neoformans. Our whole cell lipidomic analysis revealed that loss of Cdc50 disrupted membrane lipid homeostasis leading to phospholipid enrichment in cdc50{Delta} mutant, and a reduction in fatty acid production accompanied by pronounced ultrastructural defects in membrane architecture. Loss of Cdc50 also induced a hyper-vesiculating phenotype, with cdc50{Delta} producing significantly more extracellular vesicles (EVs) than wild type H99 cells. Lipidomic profiling of cdc50{Delta} EVs revealed enrichment of phospholipids, including phosphatidylserine (PS), indicating active lipid sorting during vesicle biogenesis. Functional analysis showed that EVs from the wildtype H99 suppress phagocytosis whereas cdc50{Delta} EVs enhance phagocytosis, indicating a differential macrophage priming. Despite increased PS externalization in cdc50{Delta} cells and EVs, macrophage recognition and uptake occur independent of PS-mediated efferocytosis pathways, including PS receptor MertK. Following macrophage uptake, cdc50{Delta} were intrinsically vulnerable to macrophage killing due to rapid phagosome acidification. Together, we demonstrate that Cdc50 dependent lipid homeostasis regulates EV production, lipid composition, membrane architecture and drives the intracellular fate of C. neoformans. IMPORTANCECryptococcus neoformans is the leading cause of fungal meningitis in immunocompromised individuals. Understanding how this pathogen evades host immune mediated clearance is essential for developing new treatment strategies. Here, we demonstrated that Cdc50, the regulatory subunit of fungal lipid flippase complex, regulates membrane lipid homeostasis that governs extracellular vesicles (EV) biogenesis and macrophage immune responses. Loss of Cdc50 drives global membrane lipid remodeling, hyper-production of phospholipid enriched EVs that enhance macrophage phagocytosis, while the wild-type EV reduce macrophage phagocytosis. Contrary to the prevailing assumption that phosphatidylserine (PS) externalization on the fungal surfaces mimics the mammalian "eat-me signal", we show fungal PS does not engage canonical PS receptor MertK, revealing a fundamental difference between fungal and mammalian PS biology. Furthermore, cdc50{Delta} cells are unable to resist phagosomal acidification, rendering them susceptible to macrophage killing. These findings establish how phospholipid homeostasis contributes to early host-pathogen interactions and serves as a compelling antifungal target in cryptococcosis.

microbiology↗