title: Annexin A1 Is a Key Modulator of Mesenchymal Stromal Cell-Mediated Improvements in Islet Function.
abstract: We have previously demonstrated that coculture of islets with mesenchymal stromal cells (MSCs) enhanced islet insulin secretory capacity in vitro, correlating with improved graft function in vivo. To identify factors that contribute to MSC-mediated improvements in islet function, we have used an unbiased quantitative RT-PCR screening approach to identify MSC-derived peptide ligands of G-protein-coupled receptors that are expressed by islets cells. We demonstrated high expression of annexin A1 (ANXA1) mRNA by MSCs and confirmed expression at the protein level in lysates and MSC-conditioned media by Western blot analysis and ELISA. Preculturing islets with exogenous ANXA1 enhanced glucose-stimulated insulin secretion (GSIS), thereby mimicking the beneficial influence of MSC preculture in vitro. Small interfering RNA-mediated knockdown of ANXA1 in MSCs reduced their capacity to potentiate GSIS. MSCs derived from ANXA1(-/-) mice had no functional capacity to enhance GSIS, in contrast to wild-type controls. Preculturing islets with ANXA1 had modest effects on their capacity to regulate blood glucose in streptozotocin-induced diabetic mice, indicating that additional MSC-derived factors are required to fully mimic the beneficial effects of MSC preculture in vivo. These findings demonstrate the feasibility of harnessing the MSC secretome as a defined, noncellular strategy to improve the efficiency of clinical islet transplantation protocols.
authors.affiliation: Diabetes Research Group, Division of Diabetes & Nutritional Sciences, School of Medicine, King's College London, London, U.K.
authors.forename: Chloe L
authors.initials: CL
authors.lastname: Rackham
authors.affiliation: Diabetes Research Group, Division of Diabetes & Nutritional Sciences, School of Medicine, King's College London, London, U.K.
authors.forename: Andreia E
authors.initials: AE
authors.lastname: Vargas
authors.affiliation: Diabetes Research Group, Division of Diabetes & Nutritional Sciences, School of Medicine, King's College London, London, U.K.
authors.forename: Ross G
authors.initials: RG
authors.lastname: Hawkes
authors.affiliation: Diabetes Research Group, Division of Diabetes & Nutritional Sciences, School of Medicine, King's College London, London, U.K.
authors.forename: Stefan
authors.initials: S
authors.lastname: Amisten
authors.affiliation: Diabetes Research Group, Division of Diabetes & Nutritional Sciences, School of Medicine, King's College London, London, U.K.
authors.forename: Shanta J
authors.initials: SJ
authors.lastname: Persaud
authors.affiliation: Diabetes Research Group, Division of Diabetes & Nutritional Sciences, School of Medicine, King's College London, London, U.K.
authors.forename: Amazon L F
authors.initials: AL
authors.lastname: Austin
authors.affiliation: Diabetes Research Group, Division of Diabetes & Nutritional Sciences, School of Medicine, King's College London, London, U.K.
authors.forename: Aileen J F
authors.initials: AJ
authors.lastname: King
authors.affiliation: Diabetes Research Group, Division of Diabetes & Nutritional Sciences, School of Medicine, King's College London, London, U.K. peter.jones@kcl.ac.uk.
authors.forename: Peter M
authors.initials: PM
authors.lastname: Jones
mesh_terms: D000818:Animals; D017305:Annexin A1 / Q000235:genetics* / Q000378:metabolism; D001786:Blood Glucose / Q000378:metabolism*; D015153:Blotting, Western; D018920:Coculture Techniques; D003921:Diabetes Mellitus, Experimental / Q000235:genetics* / Q000378:metabolism; D004797:Enzyme-Linked Immunosorbent Assay; D055785:Gene Knockdown Techniques; D066298:In Vitro Techniques; D007328:Insulin / Q000378:metabolism*; D000078790:Insulin Secretion; D007515:Islets of Langerhans / Q000378:metabolism*; D045164:Mesenchymal Stem Cell Transplantation; D059630:Mesenchymal Stem Cells / Q000378:metabolism*; D051379:Mice; D012333:RNA, Messenger / Q000378:metabolism*; D034741:RNA, Small Interfering; D060888:Real-Time Polymerase Chain Reaction
chemical_list: D017305:Annexin A1; D001786:Blood Glucose; D007328:Insulin; D012333:RNA, Messenger; D034741:RNA, Small Interfering; C573274:annexin A1, mouse