title: Fibrin supports human fetal islet-epithelial cell differentiation via p70(s6k) and promotes vascular formation during transplantation.
abstract: The human fetal pancreas expresses a variety of extracellular matrix (ECM) binding receptors known as integrins. A provisional ECM protein found in blood clots that can bind to integrin receptors and promote β cell function and survival is fibrin. However, its role in support of human fetal pancreatic cells is unknown. We investigated how fibrin promotes human fetal pancreatic cell differentiation in vitro and in vivo. Human fetal pancreata were collected from 15 to 21 weeks of gestation and collagenase digested. Cells were then plated on tissue-culture polystyrene, or with 2D or 3D fibrin gels up to 2 weeks, or subcutaneously transplanted in 3D fibrin gels. The human fetal pancreas contained rich ECM proteins and expressed integrin αVβ3. Fibrin-cultured human fetal pancreatic cells had significantly increased expression of PDX-1, glucagon, insulin, and VEGF-A, along with increased integrin αVβ3 and phosphorylated FAK and p70(s6k). Fibrin-cultured cells treated with rapamycin, the mTOR pathway inhibitor, had significantly decreased phospho-p70(s6k) and PDX-1 expression. Transplanting fibrin-mixed cells into nude mice improved vascularization compared with collagen controls. These results suggest that fibrin supports islet cell differentiation via p70(s6k) and promotes vascularization in human fetal islet-epithelial clusters in vivo.
authors.affiliation: 1] Children's Health Research Institute, London, Ontario, Canada [2] Department of Pathology, Western University, London, Ontario, Canada.
authors.forename: Matthew
authors.initials: M
authors.lastname: Riopel
authors.affiliation: 1] Children's Health Research Institute, London, Ontario, Canada [2] Department of Physiology and Pharmacology, Western University, London, Ontario, Canada.
authors.forename: Jinming
authors.initials: J
authors.lastname: Li
authors.affiliation: 1] Children's Health Research Institute, London, Ontario, Canada [2] Department of Physiology and Pharmacology, Western University, London, Ontario, Canada.
authors.forename: Mark
authors.identifier: 0000000184472897
authors.initials: M
authors.lastname: Trinder
authors.affiliation: Department of Obstetrics and Gynecology, Western University, London, Ontario, Canada.
authors.forename: George F
authors.initials: GF
authors.lastname: Fellows
authors.affiliation: 1] Children's Health Research Institute, London, Ontario, Canada [2] Department of Physiology and Pharmacology, Western University, London, Ontario, Canada [3] Department of Medicine, Western University, London, Ontario, Canada.
authors.forename: Rennian
authors.initials: R
authors.lastname: Wang
mesh_terms: D000818:Animals; D002454:Cell Differentiation / Q000187:drug effects*; D002478:Cells, Cultured; D004847:Epithelial Cells / Q000166:cytology / Q000187:drug effects*; D005109:Extracellular Matrix / Q000378:metabolism; D005333:Fetus / Q000166:cytology; D005337:Fibrin / Q000494:pharmacology*; D018398:Homeodomain Proteins / Q000378:metabolism; D006801:Humans; D039482:Integrin alpha5 / Q000378:metabolism; D007515:Islets of Langerhans / Q000166:cytology / Q000187:drug effects*; D016381:Islets of Langerhans Transplantation; D008297:Male; D051379:Mice; D008819:Mice, Nude; D018919:Neovascularization, Physiologic / Q000187:drug effects*; D038762:Ribosomal Protein S6 Kinases, 70-kDa / Q000378:metabolism; D015534:Trans-Activators / Q000378:metabolism; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism
chemical_list: D018398:Homeodomain Proteins; D039482:Integrin alpha5; D015534:Trans-Activators; D042461:Vascular Endothelial Growth Factor A; C084010:pancreatic and duodenal homeobox 1 protein; D005337:Fibrin; D038762:Ribosomal Protein S6 Kinases, 70-kDa