Endothelial cell (EC) activation and dysfunction have been linked to a variety of chronic vascular inflammatory disease states including insulin resistance (IR), obesity, and atherosclerosis?the major cause of morbidity and mortality in Western Societies. Proinflammatory cytokines and proatherogenic risk factors such as hyperlipidemia activate key signaling pathways such as NF-kB and MEKK/JNK and decrease protective ones such as AKT/eNOS signaling, an effect that confers pro-adhesive and pro-thrombotic properties to ECs. Therefore, suppressing the inflammatory response in the vascular endothelium may provide a novel therapeutic approach to limit IR/obesity, and atherothrombosis. MicroRNAs (miRNAs) are small, single-stranded, non-coding RNAs capable of repressing gene expression at the post-transcriptional level and are involved in a variety of pathophysiological processes including the regulation of immune and inflammatory responses. During this grant period, we identified miR-181b as a nodal regulator of endothelial cell quiescence through its regulatory effects on two major signaling pathways ? NF-kB and AKT/eNOS, and have uncovered novel targets for therapy. Preliminary and published observations now identify endothelial miR-181b as a critical determinant of systemic inflammation, obesity/IR, and atherogenesis. Furthermore, our studies highlight the relevance of microRNA-dependent targets in response to ligand-specific signaling in ECs?an emerging concept in the microRNA field. Moreover, we demonstrate that methotrexate (MTX), a clinically relevant therapy that suppresses endothelial activation, can function in a miR-181b- dependent manner. These observations provide the foundation for the central hypothesis that endothelial miR- 181b, via inhibitory effects on NF-?B and MEKK/JNK and inductive effects on AKT/eNOS signaling, regulates systemic vascular inflammation, IR/obesity, and atherosclerosis. To better understand the precise role of miR- 181b in stimuli-specific regulation of EC activation, three aims are proposed.
In Aim1, we will delineate the molecular basis for miR-181b's ability to inhibit endothelial NF-?B and MEKK/JNK and induce AKT/eNOS pathways in response to divergent stimuli.
In Aim2, we will determine the effect of altered endothelial miR-181b expression on obesity/insulin resistance and atherothrombosis.
In Aim3, we will explore the molecular mechanisms by which methotrexate (MTX) rescues miR-181b expression in ECs, and we will determine whether the anti-inflammatory effects of MTX are miR-181b-dependent. The results of these studies will provide insights regarding miR-181b-mediated control of endothelial activation and the functional consequences of miR-181b sufficiency and deficiency on insulin resistance and atherogenesis. Furthermore, studies exploring the link between miR-181b and MTX may provide insights that can be exploited for therapeutic gain in the treatment of a broad spectrum of chronic inflammatory disorders.

Public Health Relevance

The activation of the vascular endothelium is a characteristic feature seen in atherosclerosis and other chronic inflammatory diseases, an effect that may promote disease progression leading to heart attack, stroke, or peripheral vascular disease. We have identified a novel microRNA, termed miR-181b, that is rapidly reduced in response to pro-inflammatory cytokines in endothelial cells and our studies indicate that miR-181b may act to dampen vascular inflammation within the vessel wall. The proposed studies will provide a detailed understanding underlying the function of endothelial miR-181b, its target genes, and how to restore its expression in the vascular endothelium with the goal of developing novel therapies for the treatment of chronic vascular inflammatory disease.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
5R01HL115141-07
Application #
9511586
Study Section
Atherosclerosis and Inflammation of the Cardiovascular System Study Section (AICS)
Program Officer
Kirby, Ruth
Project Start
2012-08-01
Project End
2021-05-31
Budget Start
2018-06-01
Budget End
2019-05-31
Support Year
7
Fiscal Year
2018
Total Cost
Indirect Cost
Name
Brigham and Women's Hospital
Department
Type
DUNS #
030811269
City
Boston
State
MA
Country
United States
Zip Code
Haemmig, Stefan; Simion, Viorel; Feinberg, Mark W (2018) Long Non-Coding RNAs in Vascular Inflammation. Front Cardiovasc Med 5:22
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Haemmig, Stefan; Feinberg, Mark W (2017) Targeting LncRNAs in Cardiovascular Disease: Options and Expeditions. Circ Res 120:620-623
Haemmig, Stefan; Simion, Viorel; Yang, Dafeng et al. (2017) Long noncoding RNAs in cardiovascular disease, diagnosis, and therapy. Curr Opin Cardiol 32:776-783
Haemmig, Stefan; Feinberg, Mark W (2017) MicroRNAs as Harbingers of High-Risk Carotid Artery Atherosclerotic Disease? Circ Res 120:596-598
Zhang, Yu; Sun, Xinghui; Icli, Basak et al. (2017) Emerging Roles for MicroRNAs in Diabetic Microvascular Disease: Novel Targets for Therapy. Endocr Rev 38:145-168
Lin, Jibin; He, Shaolin; Sun, Xinghui et al. (2016) MicroRNA-181b inhibits thrombin-mediated endothelial activation and arterial thrombosis by targeting caspase recruitment domain family member 10. FASEB J 30:3216-26
Feinberg, Mark W; Moore, Kathryn J (2016) MicroRNA Regulation of Atherosclerosis. Circ Res 118:703-20
Feinberg, Mark W (2016) MicroRNAs as pathophysiological targets: An emerging nexus for personalized medicine in heart failure? Trends Cardiovasc Med 26:111-4

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