title: Gene expression analysis of human islets in a subject at onset of type 1 diabetes.
abstract: Swollen islet cells have been repeatedly described at onset of type 1 diabetes, but the underlying mechanism of this observation, termed hydropic degeneration, awaits characterization. In this study, laser capture microdissection was applied to extract the islets from an organ donor that died at onset of type 1 diabetes and from an organ donor without pancreatic disease. Morphologic analysis revealed extensive hydropic degeneration in 73% of the islets from the donor with type 1 diabetes. Expression levels of genes involved in apoptosis, ER stress, beta cell function, and inflammation were analyzed in isolated and laser-captured islets by qPCR. The chemokine MCP-1 was expressed in islets from the donor with type 1 diabetes while undetectable in the control donor. No other signs of inflammation were detected. There were no signs of apoptosis on the gene expression level, which was also confirmed by negative immunostaining for cleaved caspase-8. There was an increased expression of the transcription factor ATF4, involved in transcription of ER stress genes, in the diabetic islets, but no further signs of ER stress were identified. In summary, on the transcription level, islets at onset of type 1 diabetes in which many beta cells display hydropic degeneration show no obvious signs of apoptosis, ER stress, or inflammation, supporting the notion that these cells are responding normally to high glucose and eventually succumbing to beta cell exhaustion. Also, this study validates the feasibility of performing qPCR analysis of RNA extracted from islets from subjects with recent onset of T1D and healthy controls by laser capture microdissection.
authors.affiliation: IGP, Rudbeck Laboratory C11, Department of Immunology, Genetics and Pathology, Uppsala University, 751 85, Uppsala, Sweden.
authors.forename: Johan
authors.initials: J
authors.lastname: Hopfgarten
authors.forename: Per-Anton
authors.initials: PA
authors.lastname: Stenwall
authors.forename: Anna
authors.initials: A
authors.lastname: Wiberg
authors.forename: Mahesh
authors.initials: M
authors.lastname: Anagandula
authors.forename: Sofie
authors.initials: S
authors.lastname: Ingvast
authors.forename: Therese
authors.initials: T
authors.lastname: Rosenling
authors.forename: Olle
authors.initials: O
authors.lastname: Korsgren
authors.forename: Oskar
authors.initials: O
authors.lastname: Skog
mesh_terms: D051701:Activating Transcription Factor 4 / Q000235:genetics / Q000378:metabolism; D000328:Adult; D017209:Apoptosis / Q000235:genetics / Q000502:physiology; D053181:Caspase 8 / Q000235:genetics / Q000378:metabolism; D018932:Chemokine CCL2 / Q000235:genetics / Q000378:metabolism; D003922:Diabetes Mellitus, Type 1 / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D059865:Endoplasmic Reticulum Stress / Q000235:genetics / Q000502:physiology*; D006801:Humans; D007150:Immunohistochemistry; D007249:Inflammation / Q000235:genetics / Q000378:metabolism*; D007515:Islets of Langerhans / Q000378:metabolism / Q000502:physiology* / Q000648:ultrastructure; D061346:Laser Capture Microdissection; D008297:Male; D012313:RNA / Q000737:chemistry / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction
chemical_list: C497109:ATF4 protein, human; C111835:CCL2 protein, human; D018932:Chemokine CCL2; D051701:Activating Transcription Factor 4; D012313:RNA; D053181:Caspase 8