Effects of Simulated Microgravity on Mesenchymal Stem Cell Mechanosensitivity

Essentially all cells are sensitive to mechanical signals, providing the tissue and organismal level of adaptability to mechanical challenges. At cell level this adaptability is reflected as increased cytoskeletal connectivity. Our findings indicate that, while simulated microgravity (sMG) decreases cellular connectivity, application of known exercise mimetic, low intensity vibration (LIV) improves it. Here we will test the hypothesis that application of LIV during sMG will improve MSC responsiveness to high magnitude strain (HMS). To allow application of sMG on stretchable silicone membranes, cells will be encapsulated in Collagen Type I. HMS will be applied using a Flexcell-5000 device at 2%, 0.2Hz, MSCs will be subjected to sMG with or without LIV for 3 days. Following the sMG±LIV protocols, cells wills be subjected to HMS for 20 minutes. The intensity of the HMS response will be measured by the acute FAK (tyr 397) and Akt (Ser 473) phosphorylation events