Mesenchymal stem cells (MSCs) bind transforming growth factor (TGF)-b1 to their surface through the expression of GARP: effects on MSC biology and immunomodulation Carrillo-Gálvez, Ana Cobo, Mariem Cuevas-Ocaña, S Gutierrez-Guerrero, A Sanchez-Gilabert, Almudena Garcia-Perez, Angelica Muñoz, Pilar Benabdellah, Karim Toscano, Miguel Martín Molina, Francisco Anderson, Per Olof Mesenquimal stem cells GARP TGFbeta Immunomodulation Surface Mesenchymal stromal cells (MSCs) represent a promising tool for therapy in regenerative medicine, transplantation, and autoimmune disease due to their trophic and immunomodulatory activities. However, we are still far from understanding the mechanisms of action of MSCs in these processes. Transforming growth factor (TGF)-β1 is a pleiotropic cytokine involved in MSC migration, differentiation, and immunomodulation. Recently, glycoprotein A repetitions predominant (GARP) was shown to bind latency-associated peptide (LAP)/TGF-β1 to the cell surface of activated Foxp3(+) regulatory T cells (Tregs) and megakaryocytes/platelets. In this manuscript, we show that human and mouse MSCs express GARP which presents LAP/TGF-β1 on their cell surface. Silencing GARP expression in MSCs increased their secretion and activation of TGF-β1 and reduced their proliferative capacity in a TGF-β1-independent manner. Importantly, we showed that GARP expression on MSCs contributed to their ability to inhibit T-cell responses in vitro. In summary, we have found that GARP is an essential molecule for MSC biology, regulating their immunomodulatory and proliferative activities. We envision GARP as a new target for improving the therapeutic efficacy of MSCs and also as a novel MSC marker 2025-01-31T08:54:47Z 2025-01-31T08:54:47Z 2015 journal article Stem Cells. Vol: 33(1). Págs:183-195. (2015) https://hdl.handle.net/10481/101517 10.1002/stem.1821 eng open access Oxford University Press