Ferulic acid induces proliferation and differentiation of rat osteoblasts in vitro through cGMP/PKGII/ENaC signaling

Ferulic acid (FA) is an active component of the traditional Chinese herb Angelica sinensis. Numerous health benefits have been attributed to FA, but few studies have investigated the effects of FA on osteoblasts (Obs). Our work studied the effects of FA on proliferation, differentiation, and mineralization of rat calvarial Obs and examined the signaling pathways involved. Cell proliferation and differentiation were evaluated by Cell Counting Kit-8 (CCK-8) and alkaline phosphatase (ALP) assay kit, respectively. Cyclic guanosine monophosphate (cGMP)-dependent protein kinase II (PKGII) expression was silenced by small interfering RNA (siRNA). The mRNA expression was investigated by semi-quantitative PCR. FA (40-2560M) promoted Ob proliferation and differentiation; at 40-640M, FA stimulated calcified nodule formation and increased the expression of osteogenic genes encoding osteopontin and collagen-l. FA (40-2560M) increased cGMP levels in Obs and upregulated the expression of PKGII, EnaC, and ENaC mRNAs. Downregulated ENaC mRNA expression in Obs transfected with the siRNA for PKGII was reversed when FA was introduced into Obs. These results demonstrated that FA promoted proliferation, differentiation, and mineralization of Obs in vitro, and enhanced osteogenic genes expression partly through the cGMP-PKGII-ENaC signaling pathway.