Neddylation relieves cytoskeletal tension to permit primary cilia formation during mouse decidualization

Decidualization requires stromal reprogramming to establish pregnancy, yet the upstream mechanisms governing cytoskeletal remodeling remain obscure. While primary cilia direct this transformation, how stromal cells integrate post-translational modifications to regulate the mechanics of ciliogenesis remains unknown. This study aims to investigate the role of neddylation, a ubiquitin-like modification, in coordinating the structural and transcriptional plasticity required for mouse decidualization. We utilized the NAE inhibitor MLN4924 in an in vivo mouse model of artificial decidualization. To decipher the underlying molecular mechanism, we combined pharmacological blockade with genetic silencing of Uba3 and Cul3 in mouse uterine stromal cells. We employed RNA-sequencing to map global transcriptomic landscapes, complemented by real-time PCR, immunofluorescence, and Western blotting to assess ciliary dynamics and cytoskeletal architecture. Additionally, the ciliogenesis inhibitor Ciliobrevin A (CBA) was used to study the functional link between primary cilia and decidualization. Finally, we performed rescue experiments with small-molecule inhibitors of RhoA (Rhosin) and ROCK (Y27632), alongside the microtubule stabilizer Tubastatin A (TubA), to dissect the specific mechanotransduction pathways driving the observed phenotypes during mouse decidualization. We identified neddylation as a key regulator of stromal remodeling during decidualization. Pharmacological inhibition and genetic silencing significantly suppressed primary cilia formation and impaired the decidual response. Transcriptomic profiling revealed that neddylation inhibition aberrantly reactivates hormone-suppressed actomyosin contractile genes, particularly Myl9. Mechanistically, we demonstrate that neddylation selectively activates the E3 ligase Cullin 3 (Cul3) to target RhoA for degradation. Disruption of this axis leads to RhoA accumulation and excessive actomyosin contractility, creating a rigid cytoskeletal environment that restrains ciliogenesis. Remarkably, relieving cytoskeletal tension (via Rhosin or Y27632) or stabilizing microtubules (via TubA) functionally rescued the decidualization defects, overcoming the upstream transcriptional dysregulation. These findings establish the Cul3-RhoA axis as a critical mechanical checkpoint linking protein modification to the plasticity required for pregnancy success. By maintaining a low-tension state permissive for ciliogenesis, neddylation ensures the execution of the decidual program. Furthermore, our data suggest potential reproductive risks and highlight the neddylation-ciliary axis as a novel theoretical target for disorders of impaired decidualization.