Combined lipidomic and proteomic analysis of isolated human islets exposed to palmitate reveals time-dependent changes in insulin secretion and lipid metabolism

PLoS One

Kumari Ubhayasekera¹  Jonas Bergquist¹  Ernest Sargsyan²  Levon Manukyan²  Azazul Chowdhury²  Hannes Manell²  Hjalti Kristinsson²  Peter Bergsten²  Jean-Charles Sanchez³  Domitille Schvartz³  Reinhard Schneider⁴  Venkata Satagopam⁴  Kirsten Roomp⁴  Karlfried Groebe⁵ 

[1] Analytical Chemistry, Department of Chemistry and Science for Life Laboratory, Uppsala University, Uppsala, Sweden;Department of Medical Cell Biology, Uppsala University, Uppsala, Sweden;Human Protein Sciences Department, Centre Médical Universitaire, University of Geneva, Geneva, Switzerland;Luxembourg Centre for Systems Biomedicine, University of Luxembourg, Esch-Belval, Luxembourg;Pivot Biomed Science GmbH, Trier, Germany

关键词: Lipids;    Insulin;    Insulin secretion;    Cholesterol;    Fatty acids;    Proteomic databases;    Glucose;    Lipid analysis;   

DOI  :  10.1371/journal.pone.0176391

学科分类：医学（综合）

来源: Public Library of Science

【 摘 要 】

Studies on the pathophysiology of type 2 diabetes mellitus (T2DM) have linked the accumulation of lipid metabolites to the development of beta-cell dysfunction and impaired insulin secretion. In most in vitro models of T2DM, rodent islets or beta-cell lines are used and typically focus is on specific cellular pathways or organs. Our aim was to, firstly, develop a combined lipidomics and proteomics approach for lipotoxicity in isolated human islets and, secondly, investigate if the approach could delineate novel and/ or confirm reported mechanisms of lipotoxicity. To this end isolated human pancreatic islets, exposed to chronically elevated palmitate concentrations for 0, 2 and 7 days, were functionally characterized and their levels of multiple targeted lipid and untargeted protein species determined. Glucose-stimulated insulin secretion from the islets increased on day 2 and decreased on day 7. At day 7 islet insulin content decreased and the proinsulin to insulin content ratio doubled. Amounts of cholesterol, stearic acid, C16 dihydroceramide and C24:1 sphingomyelin, obtained from the lipidomic screen, increased time-dependently in the palmitate-exposed islets. The proteomic screen identified matching changes in proteins involved in lipid biosynthesis indicating up-regulated cholesterol and lipid biosynthesis in the islets. Furthermore, proteins associated with immature secretory granules were decreased when palmitate exposure time was increased despite their high affinity for cholesterol. Proteins associated with mature secretory granules remained unchanged. Pathway analysis based on the protein and lipid expression profiles implicated autocrine effects of insulin in lipotoxicity. Taken together the study demonstrates that combining different omics approaches has potential in mapping of multiple simultaneous cellular events. However, it also shows that challenges exist for effectively combining lipidomics and proteomics in primary cells. Our findings provide insight into how saturated fatty acids contribute to islet cell dysfunction by affecting the granule maturation process and confirmation in human islets of some previous findings from rodent islet and cell-line studies.

【 授权许可】

CC BY