Runx2‐mediated bcl‐2 gene expression contributes to nitric oxide protection against hydrogen peroxide‐induced osteoblast apoptosis

Abstract

Nitric oxide (NO) can regulate osteoblast activities. This study was aimed to evaluate the protective effects of pretreatment with sodium nitroprusside (SNP) as a source of NO on hydrogen peroxide-induced osteoblast insults and its possible mechanisms. Exposure of human osteosarcoma MG63 cells to hydrogen peroxide significantly increased cellular oxidative stress, but decreased ALP activity and cell viability, inducing cell apoptosis. Pretreatment with 0.3 mM SNP significantly lowered hydrogen peroxide-induced cell insults. Treatment of human MG63 cells with hydrogen peroxide inhibited Bcl-2 mRNA and protein production, but pretreatment with 0.3 mM SNP significantly ameliorated such inhibition. Sequentially, hydrogen peroxide decreased the mitochondrial membrane potential, but increased the levels of cytochrome c and caspase-3 activity. Pretreatment with 0.3 mM SNP significantly lowered such alterations. Exposure to hydrogen peroxide decreased Runx2 mRNA and protein syntheses. However, pretreatment with 0.3 mM SNP significantly lowered the suppressive effects. Runx2 knockdown using RNA interference inhibited Bcl-2 mRNA production in human MG63 cells. Protection of pretreatment with 0.3 mM SNP against hydrogen peroxide-induced alterations in ALP activity, caspase-3 activity, apoptotic cells, and cell viability were also alleviated after administration of Runx2 small interference RNA. Thus, this study shows that pretreatment with 0.3 mM SNP can protect human MG63 cells from hydrogen peroxide-induced apoptotic insults possibly via Runx2-involved regulation of bcl-2 gene expression.

GATA-3 transduces survival signals in osteoblasts through upregulation of bcl-x L gene expression

“…Our previous studies reported that pretreatment with NO can increase the translocation of Bcl-2, the other antiapoptotic protein, to mitochondria. (13,44) Thus the NO pretreatmentcaused protection against osteoblast injuries involves the antiapoptotic proteins Bcl-X L and Bcl-2. Besides mitochondria, the results by confocal microscopy revealed that pretreatment with NO also enhanced signals of Bcl-X L antibody recognition in the cytoplasm of osteoblasts.…”

“…(48) Our previous study provided in vitro evidence verifying the role of Runx2 in regulating bcl-2 gene expression in osteoblasts. (44) Thus Runx2 is involved in regulating osteoblast survival and death by modulating the expressions of Bcl-2 family proteins. Our results reveal that pretreatment with NO time-dependently increased the association of Runx2 and GATA-3.…”

Protective effect of oleanolic acid on oxidized-low density lipoprotein induced endothelial cell apoptosis

“…A viability assay was performed using a trypan blue exclusion method described previously (11). Briefly, HUVEC (2 × 10 5 cells) were cultured in 24-well tissue culture plates (Corning-Costar, Cambridge, MA, USA).…”

Nanoparticles prepared from the water extract of Gusuibu (Drynaria fortunei J. Sm.) protects osteoblasts against insults and promotes cell maturation

“…13 After drug treatment, morphologies of osteoblasts were observed and photographed using a light microscope. Rat osteoblasts (2 × 10 4 cells per well) were seeded in 96-well tissue culture plates overnight.…”

“…10,11 A variety of biomolecules participate in regulating inflammation-induced osteoblast injury. [12][13][14] Reducing such stress-caused damage can promote osteoblast maturation and bone healing. Our previous studies showed that Gusuibu, a traditional Preparation of the water extract of gusuibu (Weg) and nanoparticles of the Weg (nWeg).…”