Long Noncoding RNA Zfas1 in Diabetic Cardiomyopathy

Fibrosis is a significant problem in diabetic cardiomyopathy (DCM). Both long noncoding RNAs (LncRNAs) and miRNAs (miR) play important roles in cellular processes. miR-9 targets important extracellular matrix(ECM) protein, such as fibronectin(FN) and collagen(Col), which are upregulated in DCM. The role of ZNFX1-AS1 (Zfas1), a LncRNA targeting miR-9 in DCM is not clear. We investigated Zfas1 in vitro and in vivo and its regulatory mechanism on ECM protein through miR-9.

Microarrays were used to examine LncRNAs and miRNAs expression in ECs exposed to 25 mM glucose (HG) compare to 5 mM glucose and were validated by qPCR. Expression of ECM proteins targeted by miR-9 were examined. Luciferase assay was used to determine the interaction between miR-9 and its target genes. Cardiac tissues from streptozotocin-induced diabetic mice were examined similarly.

The array and qPCR analysis showed glucose-induced upregulation of LncRNA Zfas1 and downregulation of miR-9 in ECs. FN mRNA, Col1&4 mRNA and protein levels were increased in ECs treated with HG. Luciferase assay showed the binding of miR-9 to FN 3’-UTR and miR-9. Zfas1 silencing expression of its target genes expression in HG. Furthermore miR-9 mimics co-transfection with Zfas1 siRNA partially recovered these ECM protein expression. Interestingly, methylation blockade also reduced ECM protein expression. In the hearts of the diabetic animals, Zfas1 expression was increased and miR-9 was decreased and expression of transcripts regulated by miR-9 were increased.

These studies indicate a novel glucose-induced mechanism of increased ECM protein production, which is regulated by Zfas1 through miR-9 in diabetes. Identifying such mechanisms may lead to potential RNA based treatment for diabetic complications.