title: Islet heparan sulfate but not heparan sulfate proteoglycan core protein is lost during islet isolation and undergoes recovery post-islet transplantation.
abstract: Islet beta cells in situ express intracellular heparan sulfate (HS), a property previously shown in vitro to be important for their survival. We report that HS levels inside islet beta cells correlate with the novel intracellular localization of the HSPG core proteins for collagen type XVIII (Col18), a conventional extracellular matrix component. Syndecan-1 (Sdc1) and CD44 core proteins were similarly localized inside beta cells. During isolation, mouse islets selectively lose HS to 11-27% of normal levels but retain their HSPG core proteins. Intra-islet HS failed to recover substantially during culture for 4 days and was not reconstituted in vitro using HS mimetics. In contrast, significant recovery of intra-islet HS to ∼40-50% of normal levels occurred by 5-10 days after isotransplantation. Loss of islet HS during the isolation procedure is independent of heparanase (a HS-degrading endoglycosidase) and due, in part, to oxidative damage. Treatment with antioxidants reduced islet cell death by ∼60% and increased the HS content of isolated islets by ∼twofold compared to untreated islets, preserving intra-islet HS to ∼60% of the normal HS content of islets in situ. These findings suggest that the preservation of islet HS during the islet isolation process may optimize islet survival posttransplant.
authors.affiliation: Department of Immunology, The John Curtin School of Medical Research, The Australian National University, Canberra ACT, Australia.
authors.forename: F J
authors.initials: FJ
authors.lastname: Choong
authors.affiliation: Department of Immunology, The John Curtin School of Medical Research, The Australian National University, Canberra ACT, Australia.
authors.forename: C
authors.initials: C
authors.lastname: Freeman
authors.affiliation: Department of Immunology, The John Curtin School of Medical Research, The Australian National University, Canberra ACT, Australia.
authors.forename: C R
authors.initials: CR
authors.lastname: Parish
authors.affiliation: Department of Immunology, The John Curtin School of Medical Research, The Australian National University, Canberra ACT, Australia.
authors.forename: C J
authors.initials: CJ
authors.lastname: Simeonovic
mesh_terms: D000818:Animals; D001707:Biopsy, Needle; D002470:Cell Survival; D002478:Cells, Cultured; D003921:Diabetes Mellitus, Experimental / Q000601:surgery; D003922:Diabetes Mellitus, Type 1 / Q000473:pathology / Q000601:surgery*; D004195:Disease Models, Animal; D005434:Flow Cytometry; D019812:Heparan Sulfate Proteoglycans / Q000378:metabolism*; D006497:Heparan Sulfate / Q000378:metabolism*; D007150:Immunohistochemistry; D007515:Islets of Langerhans / Q000378:metabolism*; D016381:Islets of Langerhans Transplantation / Q000379:methods*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D018613:Microscopy, Confocal; D060888:Real-Time Polymerase Chain Reaction / Q000379:methods; D012680:Sensitivity and Specificity
chemical_list: D019812:Heparan Sulfate Proteoglycans; D006497:Heparan Sulfate
keywords: Animal models: murine; diabetes: type 1; islet isolation; islets of Langerhans