PDF(Pubmed)
Abstract：
Gasdermin D (GSDMD)-mediated pyroptotic cell death drives inflammatory cytokine release and downstream immune responses upon inflammasome activation, which play important roles in host defense and inflammatory disorders. Upon activation by proteases, the GSDMD N-terminal domain (NTD) undergoes oligomerization and membrane translocation in the presence of lipids to assemble pores. Despite intensive studies, the molecular events underlying the transition of GSDMD from an autoinhibited soluble form to an oligomeric pore form inserted into the membrane remain incompletely understood. Previous work characterized S-palmitoylation for gasdermins from bacteria, fungi, invertebrates, as well as mammalian gasdermin E (GSDME). Here, we report that a conserved residue Cys191 in human GSDMD was S-palmitoylated, which promoted GSDMD-mediated pyroptosis and cytokine release. Mutation of Cys191 or treatment with palmitoyltransferase inhibitors cyano-myracrylamide (CMA) or 2-bromopalmitate (2BP) suppressed GSDMD palmitoylation, its localization to the membrane and dampened pyroptosis or IL-1β secretion. Furthermore, Gsdmd-dependent inflammatory responses were alleviated by inhibition of palmitoylation in vivo. By contrast, coexpression of GSDMD with palmitoyltransferases enhanced pyroptotic cell death, while introduction of exogenous palmitoylation sequences fully restored pyroptotic activities to the C191A mutant, suggesting that palmitoylation-mediated membrane localization may be distinct from other molecular events such as GSDMD conformational change during pore assembly. Collectively, our study suggests that S-palmitoylation may be a shared regulatory mechanism for GSDMD and other gasdermins, which points to potential avenues for therapeutically targeting S-palmitoylation of gasdermins in inflammatory disorders.
摘要：
GasderminD（GSDMD）介导的焦转细胞死亡驱动炎症细胞因子释放和炎症小体激活后的下游免疫反应，在宿主防御和炎症性疾病中起重要作用。在被蛋白酶激活后，GSDMDN-末端结构域(NTD)在脂质存在下经历寡聚化和膜移位以组装孔。尽管进行了深入的研究，GSDMD从自抑制的可溶形式转变为插入膜中的寡聚孔形式的分子事件仍未完全理解。先前的工作表征了来自细菌的汽油的S-棕榈酰化，真菌,无脊椎动物,以及哺乳动物gasderminE（GSDME）。这里,我们报道，一个保守的残基Cys191在人类GSDMD是S-棕榈酰化，促进GSDMD介导的焦亡和细胞因子释放。Cys191突变或棕榈酰基转移酶抑制剂氰基-myr丙烯酰胺（CMA）或2-溴棕榈酸酯（2BP）治疗抑制了GSDMD棕榈酰化，其定位到膜上并抑制焦亡或IL-1β分泌。此外，Gsdmd依赖性炎症反应通过抑制棕榈酰化在体内得到缓解。相比之下,GSDMD与棕榈酰转移酶的共表达增强了细胞凋亡，虽然引入外源棕榈酰化序列完全恢复了C191A突变体的焦转活性，这表明棕榈酰化介导的膜定位可能与孔组装过程中GSDMD构象变化等其他分子事件不同。总的来说，我们的研究表明，S-棕榈酰化可能是GSDMD和其他gasdermins的共同调节机制，这指出了在炎症性疾病中治疗靶向gasdermins的S-棕榈酰化的潜在途径。
