title: Cellular origins of adult human islet in vitro dedifferentiation.
abstract: Cultured human islets can be dedifferentiated to duct-like structures composed mainly of cytokeratin+ and nestin+ cells. Given that these structures possess the potential to redifferentiate into islet-like structures, we sought to elucidate their specific cellular origins. Adenoviral vectors were engineered for beta-, alpha-, delta- or PP-cell-specific GFP expression. A double-stranded system was designed whereby cultures were infected with two vectors: one expressed GFP behind the cumate-inducible promoter sequence, and the other expressed the requisite transactivator behind the human insulin, glucagon, somatostatin or pancreatic polypeptide promoter. This system labels hormone+ cells in the islet in a cell-specific manner, allowing these cells to be tracked during the course of transformation from islet to duct-like structure. Post-infection, islets were cultured to induce dedifferentiation. Fluorescence microscopy demonstrated that alpha-, delta- and PP-cells contributed equally to the cytokeratin+ population, with minimal beta-cell contribution, whereas the converse was true for nestin+ cells. Complementary targeted cell ablation studies, using streptozotocin or similar adenoviral expression of the Bax (Bcl2-associated X protein) toxigene, validated these findings and suggested a redundancy between alpha-, delta- and PP-cells with respect to cytokeratin+ cell derivation. These results call into question the traditional understanding of islet cells as being terminally differentiated and provide support for the concept of adult islet morphogenetic plasticity.
authors.affiliation: Department of Surgery, McGill University, Montréal, QC, Canada.
authors.forename: Stephen C
authors.initials: SC
authors.lastname: Hanley
authors.forename: Amélie
authors.initials: A
authors.lastname: Pilotte
authors.forename: Bernard
authors.initials: B
authors.lastname: Massie
authors.forename: Lawrence
authors.initials: L
authors.lastname: Rosenberg
mesh_terms: D000256:Adenoviridae / Q000235:genetics; D000328:Adult; D002454:Cell Differentiation; D002478:Cells, Cultured; D005822:Genetic Vectors; D050416:Glucagon-Secreting Cells / Q000166:cytology / Q000378:metabolism; D049452:Green Fluorescent Proteins / Q000096:biosynthesis / Q000235:genetics; D006801:Humans; D050417:Insulin-Secreting Cells / Q000166:cytology / Q000378:metabolism; D007381:Intermediate Filament Proteins / Q000378:metabolism; D007515:Islets of Langerhans / Q000166:cytology* / Q000378:metabolism; D007633:Keratins / Q000378:metabolism; D009419:Nerve Tissue Proteins / Q000378:metabolism; D064231:Nestin; D010183:Pancreatic Ducts / Q000166:cytology; D050418:Pancreatic Polypeptide-Secreting Cells / Q000166:cytology / Q000378:metabolism; D011401:Promoter Regions, Genetic; D013004:Somatostatin / Q000502:physiology; D019864:Somatostatin-Secreting Cells / Q000166:cytology / Q000378:metabolism; D013234:Stem Cells / Q000166:cytology; D013311:Streptozocin / Q000494:pharmacology; D051028:bcl-2-Associated X Protein / Q000096:biosynthesis / Q000235:genetics
chemical_list: D007381:Intermediate Filament Proteins; C577484:NES protein, human; D009419:Nerve Tissue Proteins; D064231:Nestin; D051028:bcl-2-Associated X Protein; D049452:Green Fluorescent Proteins; D013004:Somatostatin; D013311:Streptozocin; D007633:Keratins