Pharmic Activation of PKG2 Alleviates Diabetes‐Induced Osteoblast Dysfunction by Suppressing PLCβ1‐Ca²⁺‐Mediated Endoplasmic Reticulum Stress

Abstract

As reported in our previous study, cinaciguat can improve implant osseointegration in type 2 diabetes mellitus (T2DM) rats by reactivating type 2 cGMP-dependent protein kinase (PKG2), but the downstream mechanisms remain unclear. In the present study, we investigated the favorable effect of cinaciguat on primary rat osteoblast, which was cultivated on titanium disc under vitro T2DM conditions (25 mM glucose and 200 μM palmitate), and clarified the therapeutic mechanism by proteomic analysis. The results demonstrated that T2DM medium caused significant downregulation of PKG2 and induced obvious osteoblast dysfunction. And overexpression of PKG2 by lentivirus and cinaciguat could promote cell proliferation, adhesion, and differentiation, leading to decreased osteoblasts injury. Besides, proteomic analysis revealed the interaction between PKG2 and phospholipase Cβ1 (PLCβ1) in the cinaciguat addition group, and we further verified that upregulated PKG2 by cinaciguat could inhibit the activation of PLCβ1, then relieve intracellular calcium overload, and suppress endoplasmic reticulum (ER) stress to ameliorate osteoblast functions under T2DM condition. Collectively, these findings provided the first detailed mechanisms responsible for cinaciguat provided a favorable effect on promoting osseointegration in T2DM and demonstrated a new insight that diabetes mellitus-induced the aberrations in PKG2-PLCβ1-Ca2+-ER stress pathway was one underlying mechanism for poor osseointegration.

Maresin1 Suppresses High-Glucose-Induced Ferroptosis in Osteoblasts via NRF2 Activation in Type 2 Diabetic Osteoporosis

“…Following cell seeding and various treatments, EdU detection was performed on day three in a 48-well plate with 6 × 10 3 cells per well. The following experimental procedures were in line with the article [ 45 ]. Finally, photographs of osteoblasts were recorded using fluorescence microscopy (Leica, Wetzlar, Germany).…”

“…Different intervention techniques were used to resuscitate MC3T3-E1 cells, transfer them to 6-well plates, and culture them for 72 h. The following procedures are consistent with those described in the article [ 45 ]. Ultrathin sections (50–70 nm) were sectioned and samples were stained sequentially with 2% uranyl acetate and lead citrate.…”