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- Selenica, M. L., et al.
(författare)
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Cystatin C reduces the in vitro formation of soluble A beta 1-42 oligomers and protofibrils
- 2007
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Ingår i: Scandinavian Journal of Clinical & Laboratory Investigation. - : Informa UK Limited. - 1502-7686 .- 0036-5513. ; 67:2, s. 179-190
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Tidskriftsartikel (refereegranskat)abstract
- There are an increasing number of genetic and neuropathological observations to suggest that cystatin C, an extracellular protein produced by all nucleated cells, might play a role in the pathophysiology of sporadic Alzheimer's disease (AD). Recent observations indicate that small and large soluble oligomers of the beta-amyloid protein (A beta) impair synaptic plasticity and induce neurotoxicity in AD. The objective of the present study was to investigate the influence of cystatin C on the production of such oligomers in vitro. Co-incubation of cystatin C with monomeric A beta 1-42 significantly attenuated the in vitro formation of A beta oligomers and protofibrils, as determined using electron microscopy (EM), dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE), immunoblotting, thioflavin T (ThT) spectrofluorimetry and gel chromatography. However, cystatin C did not dissolve preformed A beta oligomers. Direct binding of cystatin C to A beta was demonstrated with the formation of an initial 1:1 molar high-affinity complex. These observations suggest that cystatin C might be a regulating element in the transformation of monomeric A beta to larger and perhaps more toxic molecular species in vivo.
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| 2. |
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| 3. |
- Holst, Birgitte, et al.
(författare)
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G Protein-Coupled Receptor 39 Deficiency Is Associated with Pancreatic Islet Dysfunction
- 2009
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Ingår i: Endocrinology. - : The Endocrine Society. - 0013-7227 .- 1945-7170. ; 150, s. 2577-2585
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Tidskriftsartikel (refereegranskat)abstract
- G protein-coupled receptor (GPR)-39 is a seven-transmembrane receptor expressed mainly in endocrine and metabolic tissues that acts as a Zn++ sensor signaling mainly through the G(q) and G(12/13) pathways. The expression of GPR39 is regulated by hepatocyte nuclear factor (HNF)-1 alpha and HNF-4 alpha, and in the present study, we addressed the importance of GPR39 for glucose homeostasis and pancreatic islets function. The expression and localization of GPR39 were characterized in the endocrine pancreas and pancreatic cell lines. Gpr39(-/-) mice were studied in vivo, especially in respect of glucose tolerance and insulin sensitivity, and in vitro in respect of islet architecture, gene expression, and insulin secretion. Gpr39 was down-regulated on differentiation of the pluripotent pancreatic cell line AR42J cells toward the exocrine phenotype but was along with Pdx-1 strongly up-regulated on differentiation toward the endocrine phenotype. Immunohistochemistry demonstrated that GRP39 is localized selectively in the insulin-storing cells of the pancreatic islets as well as in the duct cells of the exocrine pancreas. Gpr39(-/-) mice displayed normal insulin sensitivity but moderately impaired glucose tolerance both during oral and iv glucose tolerance tests, and Gpr39(-/-) mice had decreased plasma insulin response to oral glucose. Islet architecture was normal in the Gpr39 null mice, but expression of Pdx-1 and Hnf-1 alpha was reduced. Isolated, perifused islets from Gpr39 null mice secreted less insulin in response to glucose stimulation than islets from wild-type littermates. It is concluded that GPR39 is involved in the control of endocrine pancreatic function, and it is suggested that this receptor could be a novel potential target for the treatment of diabetes. (Endocrinology 150: 2577-2585, 2009)
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