ZDHHC9-Mediated PKG1 Affects Osteogenesis by Regulating MAMs in T2DM

Palmitoylation is recognized as a prevalent posttranslational modification of proteins, which is highlighted in recent studies as a key player in regulating protein stability, subcellular localization, membrane transport, and other cellular biological processes. However, its role in peri-implant osteogenesis under type 2 diabetes mellitus (T2DM) remains unclear. During this study, the in vitro high-glucose model based on MC3T3-E1 cells demonstrated that a high-glucose environment in vitro markedly inhibited osteoblasts proliferation and osteogenesis; meanwhile, ZDHHC9 emerged as a significantly upregulated protein. Then, Zdhhc9 knockdown improved the dysfunction of osteoblasts and peri-implant osteogenesis of T2DM mice. In addition, co-immunoprecipitation and fluorescence co-localization analysis revealed an interaction between ZDHHC9 and cyclic guanosine monophosphate (GMP)-dependent protein kinase G 1 (PKG1), and silencing of Prkg1 prevented the improvement in osteoblasts with Zdhhc9 knockdown. Furthermore, we verified that Zdhhc9 knockdown and Prkg1 silencing altered the distance between the endoplasmic reticulum and mitochondria and the expression of mitochondria-associated endoplasmic reticulum membranes (MAMs)-related proteins in osteoblasts. Collectively, our data show that ZDHHC9 could regulate MAMs through palmitoylation of PKG1 to induce osteoblast dysfunction in T2DM. ZDHHC9 might become a novel therapeutic target for peri-implant osteogenesis in diabetes patients.