title: Impact of defined matrix interactions on insulin production by cultured human beta-cells: effect on insulin content, secretion, and gene transcription.
abstract: The impact of extracellular matrix on insulin production needs to be understood both to optimize the derivation of functional beta-cells for transplantation and to understand mechanisms controlling islet neogenesis and glucose homeostasis. In this study, we present evidence that adhesion to some common matrix constituents has a profound impact on the transcription, secretion, and storage of insulin by human beta-cells. The integrin-dependent adhesion of fetal beta-cells to both collagen IV and vitronectin induces significant glucose-independent insulin secretion and a substantial reciprocal decline in insulin content. Collagen IV, but not vitronectin, induces comparable responses in adult beta-cells. Inhibition of extracellular signal-regulated kinase activation abrogates matrix-induced insulin secretion and effectively preserves the insulin content of adherent beta-cells. Using real-time PCR, we demonstrate that adhesion of both fetal and adult beta-cells to collagen IV and vitronectin also results in the marked suppression of insulin gene transcription. Based on these findings, we contend that integrin-dependent adhesion and signaling in response to certain matrices can have a significant negative impact on insulin production by primary human beta-cells. Such responses were not found to be associated with cell death but may precede beta-cell dedifferentiation.
authors.affiliation: Islet Research Laboratory at the Whittier Institute for Diabetes, Department of Pediatrics, University of California at San Diego, 9894 Genesee Ave., La Jolla, CA 92037, USA.
authors.forename: Thomas
authors.initials: T
authors.lastname: Kaido
authors.forename: Mayra
authors.initials: M
authors.lastname: Yebra
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Cirulli
authors.forename: Christopher
authors.initials: C
authors.lastname: Rhodes
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Diaferia
authors.forename: Anthony M
authors.initials: AM
authors.lastname: Montgomery
mesh_terms: D002070:Butadienes / Q000494:pharmacology; D002448:Cell Adhesion / Q000502:physiology; D002478:Cells, Cultured; D024141:Collagen Type IV / Q000502:physiology; D005109:Extracellular Matrix / Q000502:physiology*; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D005333:Fetus / Q000166:cytology; D006801:Humans; D007328:Insulin / Q000096:biosynthesis* / Q000378:metabolism; D000078790:Insulin Secretion; D050417:Insulin-Secreting Cells / Q000378:metabolism*; D016023:Integrins / Q000502:physiology*; D009570:Nitriles / Q000494:pharmacology; D015398:Signal Transduction / Q000187:drug effects; D014158:Transcription, Genetic / Q000502:physiology; D019096:Vitronectin / Q000502:physiology
chemical_list: D002070:Butadienes; D024141:Collagen Type IV; D007328:Insulin; D016023:Integrins; D009570:Nitriles; C113580:U 0126; D019096:Vitronectin; D048049:Extracellular Signal-Regulated MAP Kinases