MicroRNA-194 as a modulator of vascular inflammation

• Applicant: Professor Dr. Sebastian Grundmann
• Subject Area: Cardiology, Angiology
• Term: since 2013
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 236364068

Background: Arterial occlusive diseases are the major cause of death in western countries and although many progresses have been made in the past, the molecular mechanisms of this chronic inflammatory disease are not fully understood yet. Recently, a new gene-regulation mechanism has been discovered: microRNAs. These short, non-coding RNAs regulate gene expression on a post-transcriptional level and are able to modulate large gene sets and associated signaling pathways. Currently, we are interested in the specific role of the microRNA miR-194 in inflammatory processes of the vascular system. Preliminary results: In a screening experiment, we identified miR-194 as the second top-regulated microRNA following stimulation of human umbilical vein endothelial cells (HUVECs) with the pro-inflammatory monomeric form of C-reactive protein (mCRP). Preliminary results suggest a regulation of endothelial adhesion molecules by miR-194. An overexpression of miR-194 in HUVECs by transfection of specific precursor oligonucleotides resulted in a diminished expression of both intercellular adhesion molecule 1 (ICAM-1) and vascular cell adhesion molecule 1 (VCAM-1) on protein level. A functional relevance of this finding was shown in a model of intravital microscopy of mesenteric venules: An inhibition of miR-194 in wildtype mice using a cholesterol-conjugated antisense oligonucleotide specific for this microRNA 24 hours prior to imaging led to a significant stimulation of both adhesion and rolling of leukocytes on the vessel wall, suggesting a modulation of the leukocyte-endothelial interaction by miR-194.Next-Steps: Our preliminary results indicate an anti-inflammatory role of miR-194. We will further elucidate the functional effects of miR-194 on leukocyte-endothelial interaction and expand our experiments to a mouse model of chronic vascular inflammation. We will apply a loss of function approach by AntagomiR-treatment and analyze the impact of miR-194 inhibition in LDLR-/- mice on a high cholesterol diet on both plaque size as well as plaque composition. In a next step, we will prove the possibility of a pharmacological miR-100 replacement therapy using specific precursor molecules in combination with an in vivo transfection reagent to possibly reduce atherosclerotic lesion formation. In addition, we plan to identify the underlying mechanism of the observed effects and to identify new direct and indirect target genes of miR-194 and their associated signaling pathways. Finally, we will correlate our in vitro and murine data with miR-194 expression in human serum samples of patients suffering from either acute or chronic coronary disease.Expected results: Based on our first results, we hypothesize that miR-194 is an endogenous inhibitor of the vascular inflammatory response. A positive or negative modulation of this microRNA might be a therapeutic strategy for the treatment of vascular occlusive diseases.

• DFG Programme: Research Grants