Vinculin promotes nuclear localization of TAZ to inhibit ECM stiffness-dependent differentiation into adipocytes

Abstract

Extracellular matrix (ECM) stiffness regulates the lineage commitment of mesenchymal stem cells (MSCs). Although cells sense ECM stiffness through focal adhesions, how cells sense ECM stiffness and regulate ECM stiffness-dependent differentiation remains largely unclear. In this study, we show that the cytoskeletal focal adhesion protein vinculin plays a critical role in the ECM stiffness-dependent adipocyte differentiation of MSCs. ST2 mouse MSCs differentiate into adipocytes and osteoblasts in an ECM stiffness-dependent manner. We find that a rigid ECM increases the amount of cytoskeleton-associated vinculin and promotes the nuclear localization and activity of the transcriptional coactivator paralogs Yes-associated protein (YAP, also known as YAP1) and transcriptional coactivator with a PDZ-binding motif (TAZ, also known as WWTR1) (hereafter YAP/TAZ). Vinculin is necessary for enhanced nuclear localization and activity of YAP/TAZ on the rigid ECM but it does not affect the phosphorylation of the YAP/TAZ kinase LATS1. Furthermore, vinculin depletion promotes differentiation into adipocytes on rigid ECM, while it inhibits differentiation into osteoblasts. Finally, TAZ knockdown was less effective at promoting adipocyte differentiation in vinculin-depleted cells than in control cells. These results suggest that vinculin promotes the nuclear localization of transcription factor TAZ to inhibit the adipocyte differentiation on rigid ECM.

Vinculin association with actin cytoskeleton is necessary for stiffness-dependent regulation of vinculin behavior

“…Variations in the amount of tension have been observed within the vinculin molecule at FAs [23]. In addition, vinculin is necessary for ECM stiffness-directed myoblast or adipocyte differentiation [24, 25]. In a previous study, we also showed that a stiff ECM promotes interactions between the vinculin linker region and vinexin α, resulting in the vinculin localization to lipid rafts [26] and the vinculin activation [27], thus stable localization of vinculin at FAs and vinculin resistance to CSB (cytoskeleton stabilization buffer).…”

An amphipathic helix of vinexin α is necessary for a substrate stiffness-dependent conformational change in vinculin

“…Nuclear localization of YAP/TAZ is promoted on rigid ECM in mesenchymal stem cells in a manner dependent on vinexin and vinculin expression (Kuroda et al, 2018(Kuroda et al, , 2017. To explore the role of H2 helix in the nuclear localization of YAP/TAZ, vinexin-KO MEFs re-expressing vinexin α WT or H2Q3 cultured on soft or rigid substrates were immunostained with anti-YAP/TAZ antibody (Fig.…”

“…Vinexin α (an isoform encoded by the SORBS3 gene), another FA scaffold protein, cooperates with vinculin to work as a mechanosensor of ECM stiffness Kuroda et al, 2017;Yamashita et al, 2014). On rigid ECM, vinexin α interacts with vinculin in an actomyosin contractility-dependent manner and induces the conformational change in vinculin to an open form, promoting cell migration and the nuclear localization of the transcriptional co-activators, Yes-associated protein (YAP, also known as YAP1) and transcriptional coactivator with a PDZbinding motif (TAZ, also known as WWTR1) (hereafter YAP/ TAZ).…”

Microtopography based on inverse opal structures regulates the behavior of bone marrow‐derived mesenchymal stem cells

“…MSCs can be isolated from various tissues such as bone marrow, adipose tissue, and the umbilical cord . It has been observed that bone marrow‐derived MSCs can be differentiated into osteoblasts, adipocytes, and chondrocytes in vitro under chemical and physical stimuli …”

“…[5][6][7] It has been observed that bone marrow-derived MSCs can be differentiated into osteoblasts, adipocytes, and chondrocytes in vitro under chemical and physical stimuli. [8][9][10][11][12] Studies have shown that substrates with microstructured or nanostructured surfaces could strongly influence the fate of MSCs. [13][14][15] Dalby and his colleagues reported that substrates with deliberately disordered pits in a square arrangement (±50-nm offset) induced MSCs to differentiate into osteoblasts, 16 while nanotopography with pits arranged in absolute square lattice symmetry retained stem-cell phenotype and maintained stem-cell growth of MSCs over 8 weeks.…”