Human pluripotent stem cell-derived skin organoids enabled pathophysiological model of Mycobacterium tuberculosis infection

Cutaneous tuberculosis (CTB) is an infectious disease highly associated with extracellular matrix remodeling and granuloma-driven fibrosis. Fibroblasts play crucial roles in this fibrotic process, but their specific roles in Mycobacterium tuberculosis (Mtb) skin infections remain unclear due to the lack of proper in vitro models. Here, we demonstrate that skin organoids (SKOs) derived from human induced pluripotent stem cells can model CTB infected by Mtb. Single-cell RNA analyses reveal an increase in fibroblasts, upregulation of genes involved in collagen synthesis, and enhanced collagen degradation induced by MMP2 and MMP14 in Mtb-infected SKOs. This is accompanied by the destruction of nerve cells and adipocytes. Importantly, the onset of fibrosis in Mtb-infected SKOs is dependent on the activation of the PI3K-AKT signaling pathway and transcription factor AP1 in fibroblasts. Pharmacological inhibition of PI3K-AKT and AP1 alleviates fibrosis and collagen deposition. Our findings have uncovered distinct alterations in cell populations during Mtb-induced skin fibrosis, highlighting the crucial roles of PI3K-AKT and AP1. The study demonstrates the utility of SKOs for investigating CTB pathogenesis and evaluating potential antifibrotic treatments.