Differential role of actin-binding proteins in controlling the adipogenic differentiation of human CD105-positive Wharton's Jelly cells

BackgroundWharton's Jelly cells (WJCs) can be differentiated into adipocytes by cytoskeletal reorganisation in association with changes in the mechanical properties of cells.MethodsWJCs subjected to adipocyte induction were observed changes in the cell morphology and alterations in actin filament formation. Transfection with either small interfering RNAs (siRNAs) against formin-2 (FMN-2), tropomyosin-1 (Tm-1), caldesmon (CaD), and profilin (Pro) or a pcDNA6-gelsolin (GSN)-constructed vector in WJCs was used to establish their regulatory roles in controlling adipogenesis. Phenotypic transformation of the cell shape and changes in cell surface adhesion force were determined in WJCs after transformation.ResultsThe levels of protein and mRNA expression of β-actin and several key actin binding ptoteins (ABPs) were decreased during the early stage of adipogenic induction but were recovered in the later induction. The siFMN-2, siTm-1, siCaD, and siPro gene knockdown in WJCs caused a widening of the cell shape, while WJCs overexpressing GSN retained a fibroblast cell shape. For both transformations, atomic force microscopy revealed alterations in the biomechanical signals on the cell surface. However, the adipogenic potency was increased after siFMN-2, siTm-1, siCaD, and siPro gene knockdown and decreased during GSN overexpression.ConclusionssiRNA gene knockdown of siFMN-2, siTm-1, siCaD, and siPro enhances the potency for WJCs commitment to adipocyte, while GSN overexpression modulates the PPAR-γ-independent pathway for the adipogenesis of WJCs.General significanceThe phenotypic changes associated with decreased ABP gene expression are critical for regulating the adipogenic differentiation of WJCs through the temporal control of actin filament organisation.

► Cytoskeletal remodelling is involved in governing the adipogenic induction of WJCs.
► Early downregulation of actin and ABPs is essential for the adipogenesis of WJCs.
► siRNA gene knockdown of CaD enhances the potency for WJCs commitment to adipocyte.
► GSN op regulates the PPAR-γ-independent pathway for the adipogenesis of WJCs.