ABSTRACT
TEAD4 is a member of transcriptional enhancer factor (TEF) family of transcription factors and plays a pivotal role in regulating embryonic development and muscle regeneration. Known previously, dysfunction of TEAD4 in mouse myoblasts impairs myotube development. However, the effects of TEAD4 on multipotency of muscle-derived stem cells (MDSCs) have not been clearly understood. Recently, bovine MDSCs (bMDSCs) were successfully isolated from adult bovine muscle. Our derived bMDSCs could differentiate into mesodermal cells, including myotubes, adipocytes, and osteoid cells. Our results also revealed that bMDSCs had the capacity to develop into ectodermal and endodermal lineages including neuron-like cells and insulin-secreting cells. After TEAD4 knock-down (TEAD4-KD), bMDSCs still kept the original capacity to differentiate into neuron-like cells and insulin-secreting cells, as shown by acquisition of both neuronal and pancreatic markers normally expressed in differentiated cells. However, up-regulation of CAV3 and ßMHC failed during myogenesis of bMDSCs with TEAD4-KD, although TEAD4-KD in bMDSCs did not affect osteoid cells and myotube formation. More interestingly, adipogenic differentiation of TEAD4-KD bMDSCs was significantly suppressed. During adipogenic differentiation, TEAD4-KD systematically impaired upregulation of TEAD1, TEAD2, and TEAD3, as well as the activation of C/EBP2, ADD1, and PPARγ as the key transcription factors for adipogenic differentiation. Finally, TEAD4-KD led to the failure of adipogenesis from bMDSCs. Together, our results support that TEAD4 is essential during adipogenic differentiation of bMDSCs. It has little effect on myogenesis of bMDSCs, and does not affect ostegenesis, neurogenesis, or pancreatic differentiation of bMDSCs. Our findings will be helpful for future study on the roles of the TEAD family during differentiation of MDSCs, and for controlling MDSC differentiation for stem cell applications.
ABSTRACT
Wnt signaling is intrinsic to embryonic stem cell self-renewal and mammalian development. However, the effects of wnts on ES cells self-renewal and iPS cells transduction was not clearly understood. In this study, L-Wnt3a cells that secreted activated Wnt3a protein into medium were used to produce Wnt3a condition medium (Wnt3a-CM) or feeder layer for ES cells cultivation and iPS cells transduction. The results showed that L-Wnt3a cells as feeder layer significantly promoted establishment of ES cell lines and generation of iPS cells. The ES cells robustly maintained pluripotency in Wnt3a-CM on feeder free condition. Moreover, we demonstrate that activated Wnt signaling by Wnt3a-CM at the early stage of reprogramming promoted generation of iPS cells by up-regulating Tcf3 and Tcf4, improving mesenchymal-to-epithelial transition (MET), promptly reactivating endogenous pluripotent genes, and regulating epigenetic remodeling. Taken together, L-Wnt3a cells and their condition medium could be a novel culture system to robustly maintained pluripotency of ES cells and accelerated somatic reprogramming by activating Wnt signaling.
