1. Human Islet Expression Levels of Prostaglandin E2 Synthetic Enzymes, But Not Prostaglandin EP3 Receptor, Are Positively Correlated with Markers of β-Cell Function and Mass in Nondiabetic Obesity
- Author
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Austin Reuter, Samantha Pabich, Rachel J. Fenske, Alicia M Weeks, Dawn Belt Davis, Chinmai Patibandla, Elizabeth D. Cox, Harpreet K Sandhu, Randall Nall, Cecilia E Kaiser, Margaret Punt, Nathan A. Truchan, Allison L. Brill, Michelle E. Kimple, Darby C. Peter, Benjamin Wancewicz, Ying Ge, Jeffrey M. Harrington, and Michael Daniels
- Subjects
endocrine system ,medicine.medical_specialty ,Prostaglandin E2 receptor ,medicine.medical_treatment ,Prostaglandin ,Type 2 diabetes ,Biology ,chemistry.chemical_compound ,Insulin resistance ,Downregulation and upregulation ,Internal medicine ,medicine ,Pharmacology (medical) ,Prostaglandin E3 ,Prostaglandin E2 ,Receptor ,Pharmacology ,geography ,geography.geographical_feature_category ,Insulin ,Islet ,medicine.disease ,Endocrinology ,chemistry ,lipids (amino acids, peptides, and proteins) ,medicine.drug - Abstract
We and others previously reported increased signaling through the Prostaglandin E3 Receptor (EP3), a G protein-coupled receptor (GPCR) for the arachidonic acid metabolite, prostaglandin E2 (PGE2), is associated with {beta}-cell dysfunction of type 2 diabetes (T2D). Yet, the relationship between PGE2 production and signaling and {beta}-cell function during the progression to T2D remains unclear. In this work, we assessed gene expression from a panel of cadaveric human islets from 40 non-diabetic donors with BMI values spanning the spectrum from lean to high-risk obesity. Interleukin-6 (gene symbol: IL6) and cyclooxygenase-2 (COX-2) (gene symbol: PTGS2) mRNA levels were positively correlated with donor body mass index (BMI), while EP3 (gene symbol: PTGER3) was not. IL6 was itself strongly correlated with PTGS2 and all but one of the other PGE2 synthetic pathway genes tested. About half of the islet preparations were used in glucose-stimulated- and incretin-potentiated insulin secretion assays using an EP3-specific antagonist, confirming functionally-relevant up-regulation of PGE2 production. Islets from obese donors showed no inherent {beta}-cell dysfunction and were at least equally as glucose- and incretin-responsive as islets from non-obese donors. Furthermore, insulin content, a marker of islet size known to be associated with donor BMI, was also significantly and positively correlated with islet PTGS2 expression. We conclude up-regulated islet PGE2 production and signaling may be a necessary part of the {beta}-cell adaption response, compensating for obesity and insulin resistance. Analysis of plasma PGE2 metabolite levels from a clinical cohort reveal these findings are not in conflict with the concept of further elevations in PGE2 production contributing to T2D-related {beta}-cell dysfunction where islet EP3 expression has also been up-regulated. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=126 HEIGHT=200 SRC="FIGDIR/small/429205v1_ufig1.gif" ALT="Figure 1"> View larger version (25K): org.highwire.dtl.DTLVardef@14056a7org.highwire.dtl.DTLVardef@f8fcf1org.highwire.dtl.DTLVardef@a66915org.highwire.dtl.DTLVardef@13ce208_HPS_FORMAT_FIGEXP M_FIG C_FIG
- Published
- 2021
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