Tissue-Specific RNA-Seq in Human Evoked Inflammation Identifies Blood and Adipose LincRNA Signatures

Inappropriate transcriptional activation of innate immunity is a pathological feature of several cardiometabolic disorders, but little is known about inflammatory modulation of long intergenic noncoding RNAs (lincRNAs) in disease-relevant human tissues.

Researchers at the University of Pennsylvania applied deep RNA sequencing (>500 million filtered reads per sample) to blood and adipose during low-dose experimental endotoxemia (lipopolysaccharide) in a healthy human, with targeted replication in separate individuals undergoing endotoxemia (n=6), to identify inflammatory lincRNAs. A subset of these lincRNAs was examined for expression in adipocytes and monocytes, modulation in adipose of obese humans, and overlap with genome-wide association study signals for inflammatory and cardiometabolic traits. Of a stringent set of 4284 lincRNAs, ≈11% to 22% were expressed with 201 and 56 lincRNAs modulated by lipopolysaccharide in blood or adipose, respectively. Tissue-specific expression of a subset of 6 lipopolysaccharide-lincRNAs was replicated with lipopolysaccharide modulation confirmed for all 3 expressed in blood and 2 of 4 expressed in adipose. The broader generalizability of findings in blood of subject A was confirmed by RNA sequencing in 7 additional subjects. The researchers confirmed adipocytes and monocytes as potential cell-sources of selective lipopolysaccharide-regulated lincRNAs, and 2 of these, linc-DMRT2 (P=0.002) and linc-TP53I13 (P=0.01), were suppressed in adipose of obese humans. Finally, they provide examples of lipopolysaccharide-modulated lincRNAs that overlap single nucleotide polymorphisms that are associated with cardiometabolic traits.

These findings provide novel insights into tissue-level, inflammatory transcriptome regulation in cardiometabolic diseases. These are complementary to more usual approaches limited to interrogation of DNA variations.

• Liu Y1, Ferguson JF, Xue C, Ballantyne RL, Silverman IM, Gosai SJ, Serfecz J, Morley MP, Gregory BD, Li M, Reilly MP. (2014) Tissue-Specific RNA-Seq in Human Evoked Inflammation Identifies Blood and Adipose LincRNA Signatures of Cardiometabolic Diseases. Arterioscler Thromb Vasc Biol 34(4), 902-12. [abstract]