VEGFB Promotes Myoblasts Proliferation and Differentiation through VEGFR1-PI3K/Akt Signaling Pathway.

Mingfa Ling,Gang Shu,Qingyan Jiang,Limin Lang,Xiaotong Zhu,Xiaohua Yang,Xumin Lai,Lulu Quan,Fan Li,Yiming Fu,Xin Yi,Lina Wang,Songbo Wang,Ping Gao,Shengchun Feng,Canjun Zhu

doi:10.3390/ijms222413352

Abstract

It has been demonstrated that vascular endothelial growth factor B (VEGFB) plays a vital role in regulating vascular biological function. However, the role of VEGFB in regulating skeletal muscle cell proliferation and differentiation remains unclear. Thus, this study aimed to investigate the effects of VEGFB on C2C12 myoblast proliferation and differentiation and to explore the underlying mechanism. For proliferation, VEGFB significantly promoted the proliferation of C2C12 myoblasts with the upregulating expression of cyclin D1 and PCNA. Meanwhile, VEGFB enhanced vascular endothelial growth factor receptor 1 (VEGFR1) expression and activated the PI3K/Akt signaling pathway in a VEGFR1-dependent manner. In addition, the knockdown of VEGFR1 and inhibition of PI3K/Akt totally abolished the promotion of C2C12 proliferation induced by VEGFB, suggesting that VEGFB promoted C2C12 myoblast proliferation through the VEGFR1-PI3K/Akt signaling pathway. Regarding differentiation, VEGFB significantly stimulated the differentiation of C2C12 myoblasts via VEGFR, with elevated expressions of MyoG and MyHC. Furthermore, the knockdown of VEGFR1 rather than NRP1 eliminated the VEGFB-stimulated C2C12 differentiation. Moreover, VEGFB activated the PI3K/Akt/mTOR signaling pathway in a VEGFR1-dependent manner. However, the inhibition of PI3K/Akt/mTOR blocked the promotion of C2C12 myoblasts differentiation induced by VEGFB, indicating the involvement of the PI3K/Akt pathway. To conclude, these findings showed that VEGFB promoted C2C12 myoblast proliferation and differentiation via the VEGFR1-PI3K/Akt signaling pathway, providing new insights into the regulation of skeletal muscle development.

Highlights

Skeletal muscle is a vital organ, which occupies 30–40% of the body
The activation of the PI3K/Akt/mTOR signaling pathway induced by vascular endothelial growth factor B (VEGFB) was eliminated by VEGFRs inhibitor axitinib (Figure 6A,B) and vascular endothelial growth factor receptor 1 (VEGFR1) siRNA (Figure 6C,D), indicating a link between VEGFR1 and PI3K/Akt/mTOR signaling activation. These results suggested that VEGFB activated the PI3K/Akt/mTOR signaling pathway in a VEGFR1-dependent manner and implied the possible involvement of the PI3K/Akt/mTOR signaling pathway in VEGFBstimulated C2C12 differentiation
We found that the expressions of VEGFR1 and neuropilin 1 (NRP1) were both enhanced by VEGFB in the proliferation and differentiation subjects, implying the possible involvement of VEGFR1 and NRP1 in C2C12 myoblast proliferation and differentiation

Summary

Introduction

Skeletal muscle is a vital organ, which occupies 30–40% of the body. The basic functions of the skeletal musculature include facilitating locomotor activity, postural behavior, and breathing, and proper muscle formation and function are required for a healthy life [1]. Myogenesis is a highly orchestrated process that involves myoblast proliferation, migration, and differentiation, as well as the fusion of multicellular myotubes into contractile skeletal muscle fibers [5]. Promoting the proliferation and differentiation of myoblasts and inducing myotube hypertrophy should be beneficial for muscle growth and muscle mass regulation. During myogenesis in adult mammalian skeletal muscle, activated myogenic progenitors, called myoblasts, undergo several rounds of proliferation to increase the myogenic pool needed for muscle growth or tissue repair. Studies have revealed that the PI3K/Akt signaling pathway is involved in myoblast proliferation by regulating the cell-cycle proteins [8,9]. Skeletal muscle growth and development can benefit from the regulation of the PI3K/Akt signaling pathway and downstream target genes

Objectives

Results

Conclusion