Betaine regulates adipogenic and osteogenic differentiation of hAD-MSCs

With an ageing population, the incidence of bone loss and obesity are increasing. Numerous studies emphasized the multidirectional differentiation ability of mesenchymal stem cells (MSCs), and reported betaine modulated the osteogenic differentiation and adipogenic differentiation of MSCs in vitro. We wondered how betaine affected the differentiation of hAD-MSCs and hUC-MSCs.

ALP staining and alizarin red S (ARS) staining were proved 10 mM betaine significantly increased the number of ALP-positive cells and plaque calcified extracellular matrices, accompanying by the up-regulation of OPN, Runx-2 and OCN. Oil red O staining demonstrated the number and size of lipid droplets were reduced, the expression of adipogenic master genes such as PPARγ, CEBPα and FASN were down-regulated simultaneously. For further investigating the mechanism of betaine on hAD-MSCs, RNA-seq was performed in none-differentiation medium. The Gene Ontology (GO) analysis showed fat cell differentiation and bone mineralization function terms were enriched, and KEGG showed PI3K-Akt signaling pathway, cytokine-cytokine receptor interaction and ECM-receptor interaction pathways were enriched in betaine treated hAD-MSCs, demonstrated betaine had a positive inducing effect on osteogenic of hAD-MSCs in the non-differentiation medium in vitro, which is opposite to the effect on adipogenic differentiation.

Our study demonstrated that betaine promoted osteogenic and compromised adipogenic differentiation of hUC-MSCs and hAD-MSCs upon low concentration administration. PI3K-Akt signaling pathway, cytokine-cytokine receptor interaction and ECM-receptor interaction were significantly enriched under betaine-treated. We showed hAD-MSCs were more sensitive to betaine stimulation and have a better differentiation ability than hUC-MSCs. Our results contributed to the exploration of betaine as an aiding agent for MSCs therapy.