Endosulfan rewires GSK3β to disrupt primary cilia-dependent Hedgehog signalling

Abstract

Primary cilium-dependent hedgehog signalling governs embryonic patterning and organ homeostasis, and its dysfunction causes ciliopathies, a clinically diverse spectrum of developmental and reproductive disorders. Whether environmental chemicals can produce ciliopathy-like phenotypes by acting directly on cilia or ciliary signalling remains unknown. Endosulfan, a banned yet still-used organochlorine pesticide whose bioaccumulation has been linked to widespread congenital malformations, infertility, and cerebral palsy in exposed human populations, offers a compelling test case. Here we show that endosulfan suppresses hedgehog signalling across multiple ciliated cell types and in the gonads of exposed mice by driving proteolytic conversion of GLI transcription factors into repressive forms. Systematically excluding ciliary receptor trafficking, cAMP signalling, and GLI-DNA binding, we identify the kinases PKA and GSK3{beta} as direct endosulfan targets. Endosulfan allosterically fine-tunes PKA activity and, in a pharmacologically unprecedented finding, acts as the small-molecule activator of GSK3{beta}, stabilising its active conformation through a conformational-selection mechanism distinct from known GSK3{beta} inhibitors. Beyond canonical hedgehog targets, we identify Cetn3 and Cep250 as novel GLI-regulated genes required for centriole cohesion, both repressed by endosulfan, providing a candidate molecular link to the reproductive phenotypes documented in exposed humans and animal models. Together, these findings establish a chemical-biological axis through which a widespread environmental toxicant hijacks core developmental kinase signalling to phenocopy a genetic ciliopathy, and identify GSK3{beta} conformational activation as a previously unrecognised mode of kinase pharmacology.