Abstract
FAK and Src signaling play important roles in cell differentiation, survival and migration. However, it remains unclear how FAK and Src activities are regulated at the initial stage of stem cell differentiation. We utilized fluorescence resonance energy transfer (FRET)-based FAK and Src biosensors to visualize these kinase activities at the plasma membrane of human mesenchymal stem cells (HMSCs) under the stimulation of osteogenic, myoblastic, or neural induction reagents. Our results indicate that the membrane FAK and Src activities are distinctively regulated by these differentiation induction reagents. FAK and Src activities were both up-regulated with positive feedback upon osteogenic induction, while myoblastic induction only activated Src, but not FAK. Neural induction, however, transiently activated FAK and subsequently Src, which triggered a negative feedback to partially inhibit FAK activity. These results unravel distinct regulation mechanisms of FAK and Src activities during HMSC fate decision, which should advance our understanding of stem cell differentiation in tissue engineering.
Highlights
Human mesenchymal stem cells (HMSCs) can be renewed and allowed to differentiate into cells of mesenchymal as well as nonmesenchymal lineages, with ample applications in tissue engineering and regenerative medicine [1,2]
The change of focal adhesion kinase (FAK) and Src activities in HMSCs treated with osteogenic induction reagent To study FAK and Src activities during induced differentiation, we treated single live HMSCs with different components of the differentiation induction reagents
The responses of FAK ECFP/fluorescence resonance energy transfer (FRET) ratio to these three treatments were not significantly different from each other (Fig. 1C). These results indicate that FAK in the HMSCs was significantly activated by the combined osteogenic mixture, probably attributing to its individual components DEX and Vitamine C (Vit), but not SG
Summary
Human mesenchymal stem cells (HMSCs) can be renewed and allowed to differentiate into cells of mesenchymal as well as nonmesenchymal lineages, with ample applications in tissue engineering and regenerative medicine [1,2]. The differentiation signals are transduced from the membrane receptors of HMSCs to transcription factors and genes in the nucleus, modulated by complex intracellular signaling networks [3,4]. The importance of these regulatory signaling pathways in the development and maintenance of the skeleton, muscle, and neuron is widely accepted [5]. The signaling pathways regulating stem cell differentiation can be initiated by cytokines, growth factors, or extracellular mechanical environment [7,8,9]. FAK and Src can regulate a cell’s fate decision either cooperatively or independently
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
