Islet protein expression changes during diabetes development in islet syngrafts in BB-DP rats and during rejection of BB-DP islet allografts.
Interleukin 1beta (IL-1) is cytotoxic to rat pancreatic beta-cells in vitro, and increased expression of IL-1 mRNA is found in the islets of Langerhans during development of diabetes in BB/Wor/Mol-BB2 (BB-DP) rats and NOD mice. It has been proposed that IL-1 induces a race between protective and deleterious proteins in the beta-cells during development of diabetes, and that heat shock proteins 70 and 90, and manganese superoxide dismutase, all inducible by IL-1 are potentially protective proteins. We have established a database of approximately 2000 neonatal rat-islet proteins by two-dimensional gel (2-D gel) electrophoresis of [35S]-methionine labelled neonatal Wistar Furth rat islets. In these IL-1 was shown to up- or down-regulate the islet-expression level of 99, and to induce de novo synthesis of 6 proteins. The identity of most of the IL-1 induced proteins is unknown and under study. In this study we wished to investigate if changes in protein expression induced in vitro by IL-1 stimulation of islets are also seen in vivo during spontaneous development of diabetes in BB-DP rats, and during islet allograft rejection. Two-hundred neonatal BB-DP rat islets were grafted under the kidney capsule of either 30-day-old BB-DP rats killed at onset of diabetes or of 30-day-old Wistar Kyoto (WK) rats, killed 12 days after grafting. Proteins in excised islet-grafts and in vitro IL-1 exposed isolated neonatal BB-DP rat islets were labelled with [35S]-methionine, and processed for 2-D gel electrophoresis. Fluorographs of the gels were analysed by computer. A total of 1815 proteins were found in 3 of 3 12.5% polyacrylamide gels. Interleukin-1 was found to change expression level of 82 of these proteins (22 up- and 60 down-regulated) in neonatal BB-DP rat islets in vitro. Of these 82 proteins 33 (4 up- and 29 down-regulated) also changed level of expression during disease occurrence in syngeneic islet grafts from diabetic BB-DP rats, and 29 (4 up- and 25 down-regulated) during rejection of BB-DP islets grafted to WK rats. Changes in the expression level of 14 (3 up- and 11 down-regulated) of the 82 proteins altered by IL-1 in vitro were only found in syngeneic islet grafts in diabetic BB-DP rats, and changes in the expression level of 8 (2 up- and 6 down-regulated) of these 82 proteins expression were only found in BB-DP islet allografts in WK recipients. Identification of these proteins may be important in understanding the mechanisms of islet destruction during development of insulin-dependent diabetes mellitus and during islet allograft rejection.
Christensen
U B
UB
Steno Diabetes Center, Gentofte, Denmark.
Larsen
P M
PM
Fey
S J
SJ
Andersen
H U
HU
Nawrocki
A
A
Sparre
T
T
Mandrup-Poulsen
T
T
Nerup
J
J
D000818:Animals; D000831:Animals, Newborn; D001345:Autoradiography; D002478:Cells, Cultured; D003922:Diabetes Mellitus, Type 1 / Q000378:metabolism*; D015180:Electrophoresis, Gel, Two-Dimensional; D006084:Graft Rejection / Q000378:metabolism*; D007328:Insulin / Q000032:analysis; D007375:Interleukin-1 / Q000494:pharmacology; D007515:Islets of Langerhans / Q000187:drug effects / Q000378:metabolism*; D016381:Islets of Langerhans Transplantation; D009569:Nitric Oxide / Q000032:analysis; D011506:Proteins / Q000378:metabolism*; D051381:Rats; D011913:Rats, Inbred BB; D014184:Transplantation, Homologous; D014185:Transplantation, Isogeneic
D007328:Insulin; D007375:Interleukin-1; D011506:Proteins; D009569:Nitric Oxide