Session: MON 818-841-Diabetes Pathophysiology & Complications
Poster Board MON-829
Objective: The objective of this study is to determine if iPLA2β promotes β-cell apoptosis by regulating RAGE splicing.
Design: A chemical inhibitor (S-BEL) or siRNA was used to suppress iPLA2β in INS-1 cells. Livers were isolated from wild type and iPLA2b-/-mice. RNA was isolated, cDNA generated, and RT-PCR performed to amplify splice variants of RAGE. PCR signals were quantified and the ratio of putative full length RAGE (lacks introns 9 and 10) to putative esRAGE (contains introns 9 and 10) was determined.
Results: In INS-1 cells, iPLA2β inactivation or knockdown shifted splicing in favor of a RAGE splice variant that included introns 9 and 10, typically increasing the ratio of esRAGE/ FL-RAGE by approximately 2-fold. Similarly, iPLA2b-/- mouse liver exhibited a 2-3 fold increase in the ratio of intron 9+/ intron9- splice variant. At present, our efforts are focused on cloning and sequencing these splice variants, to confirm that they encode FL-RAGE and esRAGE. We are also using immunoblot and flow cytometry to characterize RAGE proteins in cells and tissues with high versus low levels of iPLA2b activity.
Conclusions: These data suggest that iPLA2β modulates pre-mRNA splicing of RAGE, shifting splicing to favor a variant that promotes apoptosis. A more complete understanding of the molecular mechanisms underlying iPLA2β- regulated pre-mRNA splicing may uncover novel targets to control these splicing events, suppress β-cell apoptosis, and thereby treat diabetes mellitus.
Nothing to Disclose: MK, XL, SR, SB
*Please take note of The Endocrine Society's News Embargo Policy at http://www.endo-society.org/endo2013/media.cfm
See more of: Abstracts - Orals, Featured Poster Presentations, and Posters