MBTPS1 and nephrosis: To explore the mechanisms of AAV-SPL 2.0-mediated protection against SPLIS nephrosis at the molecular level, we investigated the activation state of the STAT3 pathway, which is known to be activated by S1P signaling and has been reported to contribute to the pathogenesis of diabetic kidney disease, Alport syndrome, lupus nephritis, nephrotoxic nephritis, and polycystic kidney disease [27,28,29].