Abstract 432: Linc-ADAIN, A Novel Human Adipose LincRNA Modulated By Obesity, Can Regulate Adipocyte Cytokine Secretion.

Abstract

Background: Dysfunctional adipose tissue (AT), characterized by increased inflammation and immune cell recruitment, plays a central role in the development of T2DM and atherosclerotic CVDs. LincRNAs are important emerging regulators of cellular functions. Methods: RNA-seq of human AT during low-dose endotoxemia, identified novel lincRNAs regulated by inflammation. LincADAIN was identified as 1)specifically expressed in AT 2)reduced in both obesity-induced chronic and LPS-induced acute AT inflammation (-77% and -53%, p<0.05). Most lincRNAs (~80%) are not conserved hence, we utilized a humanized mouse model. NSG mice are transplanted with human ASC-adipocytes that have undergone lentiviral shRNA knockdown and adipogenic induction in vitro , prior to injection. After 16 weeks, implants are extracted and analyzed for adipocyte morphology, immune cell infiltration and gene expression changes. Biotinylated lincRNA pulldown assay was used to identify interacting proteins by Mass Spectrometry (MS) and hits validated via RNA IP assays. Cytokines from LPS stimulated adipocytes after Linc-ADAIN KD were measured via cytokine array. Results: Human LincADAIN expression negatively correlates to BMI in obese AT (p<0.001, r2-0.3042). PPARγ antagonist treatment reduced LincADAIN expression. KD of LincADAIN in ASC-adipocytes, increased protein but not mRNA levels of inflammatory cytokines, IL-8 and MCP-1. Cellular fractionation shows that LincADAIN is mostly cytoplasmic. MS analysis of LincADAIN pulldown proteins revealed central RNA binding proteins (RBPs) such as HuR, as potential interactors, which may post-transcriptionally regulate inflammatory cytokines. Changes in human circulating adiponectin was detected in the NSG mouse serum, indicating the implants are functional. Conclusion: Linc-ADAIN is a novel lincRNA that can regulate AT inflammation potentially through modulation of RNA translation via RBPs. Our mouse model provides a foundation to uncover Linc-ADAIN’s role in AT inflammation in vivo and to study other non-conserved human lincRNAs. Functional investigations of lincRNAs, such as these are warranted, as recent genomic studies suggest that lincRNAs are likely the causal element driving human disease at some GWAS loci.