BMP‐2 Induced Expression of PLCβ1 That is a Positive Regulator of Osteoblast Differentiation

Abstract

Bone morphogenetic protein 2 (BMP-2) is a critical growth factor that directs osteoblast differentiation and bone formation. Phosphoinositide-phospholipase Cβ 1 (PLCβ1) plays a crucial role in the initiation of the genetic program responsible for muscle differentiation. Differentiation of C2C12 mouse myoblasts in response to insulin stimulation is characterized by a marked increase in nuclear PLCβ1. Here, the function of PLCβ1 in the osteogenic differentiation was investigated. Briefly, in C2C12 cells treated with BMP-2 we assist to a remarkable increase in PLCβ1 protein and mRNA expression. The data regarding the influence on differentiation demonstrated that PLCβ1 promotes osteogenic differentiation by up-regulating alkaline phosphatase (ALP). Moreover, PLCβ1 is present in the nuclear compartment of these cells and overexpression of a cytosolic-PLCβ1mutant (cyt-PLCβ1), which lacks a nuclear localization sequence, prevented the differentiation of C2C12 cells into osteocytes. Recent evidence indicates that miRNAs act as important post transcriptional regulators in a large number of processes, including osteoblast differentiation. Since miR-214 is a regulator of Osterix (Osx) which is an osteoblast-specific transcription factor that is needful for osteoblast differentiation and bone formation, we further investigated whether PLCβ1 could be a potential target of miR-214 in the control of osteogenic differentiation by gain- and loss- of function experiment. The results indicated that inhibition of miR-214 in C2C12 cells significantly enhances the protein level of PLCβ1 and promotes C2C12 BMP-2-induced osteogenesis by targeting PLCβ1.

miR-214 suppresses the osteogenic differentiation of bone marrow-derived mesenchymal stem cells and these effects are mediated through the inhibition of the JNK and p38 pathways

“…The downregulation of miR-214 enhanced ALP activity, and increased Col I, OCN and OPN gene expression in the BMSCs. Ramazzotti et al (17) indicated that the inhibition of miR-214 enhanced ALP activity and osterix expression in C2C12 cells.…”

Molecular Mechanisms of Obesity-Induced Osteoporosis and Muscle Atrophy

“…BMP signaling has been identified as the major effector in preosteoblasts because binding of BMP with its receptor (BMPRs) activates target genes through SMAD dependent pathways or SMAD independent pathways (Chen G. et al, 2012 ) (Figure 2 ). It has recently been identified that BMP-2 exerts its effects on osteoblasts by inducing the expression of two potential osteoblastogenic factors, Phospholipase C β1 (PLCβ1) and Leucine-Rich Repeat Containing G Protein-Coupled Receptor 4 (LGR4) (Pawaputanon Na Mahasarakham et al, 2015 ; Ramazzotti et al, 2016 ). The net effect of activation of BMP signaling is to activate transcription factors necessary for the induction of osteogenesis.…”

The Emerging Roles of the Calcineurin-Nuclear Factor of Activated T-Lymphocytes Pathway in Nervous System Functions and Diseases

“…A study addressing the suitability of rat striatal primordia-derived ST14A cell line for the study of voltage-gated Ca 2+ channel of striatal medium spiny neurons called for serious caution on the assumption of the presence of complete signaling cascades of G-protein coupled receptors in cell lines [260]. Notably, ST14A cells were reported to lack PLC- β 1, a major effector of G-proteins for Ca 2+ release from intracellular stores [59, 82], whose roles include (i) the regulation of forward locomotion in wild-type mice, among other dopamine receptor functions [261]; (ii) the mediation of Ca 2+ flux required for mammalian sperm acrosome reaction [262]; and (iii) the mediation of the positive regulation of osteoblast differentiation [263]. In addition, most observations from studies in preclinical models of neurodegenerative diseases based on exogenous neurotoxins are not confirmed by clinical studies [264–266].…”