Francesca Bortolotti1, Giulia Ruozi1, Antonella Falcione1, Sara Doimo1, Matteo Dal Ferro1, Pierluigi Lesizza1, Lorena Zentilin1, Lawrence Banks1, Serena Zacchigna1, Mauro Giacca2. 1. From Molecular Medicine (F.B., G.R., A.F., L.Z., M.G.), Tumour Biology (L.B.), and Cardiovascular Biology (S.Z.) Laboratories, International Centre for Genetic Engineering and Biotechnology, Trieste, Italy; Department of Medical, Surgical and Health Sciences, University of Trieste, Italy (S.D., M.D.F., P.L., S.Z., M.G.); and Center for Translational Cardiology, Azienda Sanitaria Integrata di Trieste, Italy (S.D., M.D.F., P.L., S.Z., M.G.). 2. From Molecular Medicine (F.B., G.R., A.F., L.Z., M.G.), Tumour Biology (L.B.), and Cardiovascular Biology (S.Z.) Laboratories, International Centre for Genetic Engineering and Biotechnology, Trieste, Italy; Department of Medical, Surgical and Health Sciences, University of Trieste, Italy (S.D., M.D.F., P.L., S.Z., M.G.); and Center for Translational Cardiology, Azienda Sanitaria Integrata di Trieste, Italy (S.D., M.D.F., P.L., S.Z., M.G.). giacca@icgeb.org.
Abstract
BACKGROUND: Transplantation of cells into the infarcted heart has significant potential to improve myocardial recovery; however, low efficacy of cell engraftment still limits therapeutic benefit. Here, we describe a method for the unbiased, in vivo selection of cytokines that improve mesenchymal stromal cell engraftment into the heart both in normal conditions and after myocardial infarction. METHODS: An arrayed library of 80 secreted factors, including most of the currently known interleukins and chemokines, were individually cloned into adeno-associated viral vectors. Pools from this library were then used for the batch transduction of bone marrow-derived mesenchymal stromal cells ex vivo, followed by intramyocardial cell administration in normal and infarcted mice. Three weeks after injection, vector genomes were recovered from the few persisting cells and identified by sequencing DNA barcodes uniquely labeling each of the tested cytokines. RESULTS: The most effective molecule identified by this competitive engraftment screening was cardiotrophin-1, a member of the interleukin-6 family. Intracardiac injection of mesenchymal stromal cells transiently preconditioned with cardiotrophin-1 preserved cardiac function and reduced infarct size, parallel to the persistence of the transplanted cells in the healing hearts for at least 2 months after injection. Engraftment of cardiotrophin-1-treated mesenchymal stromal cells was consequent to signal transducer and activator of transcription 3-mediated activation of the focal adhesion kinase and its associated focal adhesion complex and the consequent acquisition of adhesive properties by the cells. CONCLUSIONS: These results support the feasibility of selecting molecules in vivo for their functional properties with adeno-associated viral vector libraries and identify cardiotrophin-1 as a powerful cytokine promoting cell engraftment and thus improving cell therapy of the infarcted myocardium.
BACKGROUND: Transplantation of cells into the infarcted heart has significant potential to improve myocardial recovery; however, low efficacy of cell engraftment still limits therapeutic benefit. Here, we describe a method for the unbiased, in vivo selection of cytokines that improve mesenchymal stromal cell engraftment into the heart both in normal conditions and after myocardial infarction. METHODS: An arrayed library of 80 secreted factors, including most of the currently known interleukins and chemokines, were individually cloned into adeno-associated viral vectors. Pools from this library were then used for the batch transduction of bone marrow-derived mesenchymal stromal cells ex vivo, followed by intramyocardial cell administration in normal and infarctedmice. Three weeks after injection, vector genomes were recovered from the few persisting cells and identified by sequencing DNA barcodes uniquely labeling each of the tested cytokines. RESULTS: The most effective molecule identified by this competitive engraftment screening was cardiotrophin-1, a member of the interleukin-6 family. Intracardiac injection of mesenchymal stromal cells transiently preconditioned with cardiotrophin-1 preserved cardiac function and reduced infarct size, parallel to the persistence of the transplanted cells in the healing hearts for at least 2 months after injection. Engraftment of cardiotrophin-1-treated mesenchymal stromal cells was consequent to signal transducer and activator of transcription 3-mediated activation of the focal adhesion kinase and its associated focal adhesion complex and the consequent acquisition of adhesive properties by the cells. CONCLUSIONS: These results support the feasibility of selecting molecules in vivo for their functional properties with adeno-associated viral vector libraries and identify cardiotrophin-1 as a powerful cytokine promoting cell engraftment and thus improving cell therapy of the infarcted myocardium.