Prevalence of over-nutrition and metabolic syndrome (MetS) drive the epidemic of cardiovascular disease (CVD), the leading cause of death in the United States. Insulin (INS) resistance that underlies MetS exacerbates vascular complications, cardiovascular remodeling, and CVD associated mortality. The standard of care for the treatment of CVD involves extensive use of anti-inflammatory drugs such as rapamycin (Rap) to prevent vascular restenosis and dexamethasone (Dexa) to manage inflammation. However, accumulating evidence strongly suggest that chronic Rap/Dexa treatments further exacerbate INS resistance in conditions of MetS. Exact mechanism for Rap/Dexa-induced INS resistance is currently unclear. Both Rap and Dexa inhibit mTOR Complex 1 (mTORC1), a nutrient sensor kinase activated in conditions of over-nutrition and MetS and implicated in INS resistance. It is a conundrum that Rap/Dexa increase INS resistance despite inhibiting mTORC1. The basis of this proposal is our unprecedented observation that mTORC1 suppresses the microRNA miR-29 that in turn inhibits the Angiotensin II (Ang II) receptor AT2R, a cardiovascular (CV) protective molecule. The miR-29 induces INS resistance and is up-regulated in tissues and serum of diabetic rodent models and humans. Our in silico and in vitro studies showed that miR-29 suppresses AT2R. Thereby, we hypothesize that mTORC1 activation in conditions of over-nutrition increases AT2R expression as a CV protective mechanism via suppression of miR-29. Since activation of the AT2R induces vasodilatation and inhibits excessive growth, we further hypothesize that activation of the AT2R offers CV protection in MetS. Our conceptually novel hypothesis derived based on our preliminary data and evidence from literature is that Rap and Dexa increase expression of miR-29 that exacerbates INS resistance in CV tissues and attenuates AT2R-mediated CV protection in conditions of MetS. Furthermore, we propose that a novel AT2R agonist, Novokinin (Nov), that regulates mTOR without increasing miR-29 in CV tissues would be an ideal drug to regulate INS resistance and promote CV protection in MetS.
In Aim 1, we will investigate if Rap or Dexa disrupts mTORC1->miR-29->AT2R axis by increasing miR-29 and suppressing AT2R and exacerbates CVD in rat models of obesity, INS resistance and hyperinsulinemia.
In Aim 2 we will determine if Nov restores mTORC1->miR-29->AT2R axis by regulating miR-29 expression and activating the AT2R, and provides enhanced CV protection in rat models of obesity and MetS that are subjected to Rap or Dexa treatments. Results of this integrative and translationally innovative investigation will unveil potential adverse CV outcomes associated with Rap or Dexa treatments in conditions of MetS. Importantly, they will determine the efficacy of a new CV protective drug, Nov, in ameliorating INS resistance and CVD in conditions of Rap/Dexa treatments in MetS. We expect that the results of these studies will have significant translational value since they will have considerabl impact on the standard of care for CVD in MetS.

Public Health Relevance

The fact that one in every three deaths in the United States is caused by cardiovascular disease (CVD) highlights the urgent need for novel therapeutic strategies to combat this disease. Prevalence of over-nutrition and metabolic syndrome (MetS) drive the epidemic of CVD. Insulin resistance that underlies MetS exacerbates vascular complications and increases CVD associated mortality. The standard of care for the treatment of CVD involves extensive use of anti-inflammatory drugs such as rapamycin (Rap) (for example Rap eluting stents) to prevent vascular restenosis and dexamethasone (Dexa) to reduce inflammation. However, accumulating evidence strongly suggest that chronic Rap/Dexa treatments further exacerbate insulin resistance and promote more severe CVD. This proposal seeks funding to investigate a novel therapeutic strategy to attenuate the progression of CVD in conditions of MetS. This approach employs a novel drug, Novokinin (Nov)that suppresses insulin resistance by regulating the diabetic marker miR-29, and promotes vasodilatation and cardiovascular protection by activating the AT2R, a member of the vaso-protective axis of renin-angiotensin system. Results of this integrative and translationally innovative investigation will determine whether Nov attenuates Rap/Dexa-induced insulin resistance in cardiovascular tissues in conditions of MetS and will have a significant impact on the standard of care for CVD in MetS.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
5R01HL118376-03
Application #
8842191
Study Section
Special Emphasis Panel (ZRG1-VH-B (02))
Program Officer
Olive, Michelle
Project Start
2013-07-03
Project End
2018-04-30
Budget Start
2015-05-01
Budget End
2016-04-30
Support Year
3
Fiscal Year
2015
Total Cost
$441,545
Indirect Cost
$144,423
Name
University of Missouri-Columbia
Department
Internal Medicine/Medicine
Type
Schools of Medicine
DUNS #
153890272
City
Columbia
State
MO
Country
United States
Zip Code
65211
Sharma, Neekun; Dev, Rishabh; Belenchia, Anthony M et al. (2018) Deficiency of IL12p40 (Interleukin 12 p40) Promotes Ang II (Angiotensin II)-Induced Abdominal Aortic Aneurysm. Arterioscler Thromb Vasc Biol :ATVBAHA118311969
Lum-Naihe, Kelly; Toedebusch, Ryan; Mahmood, Abuzar et al. (2017) Cardiovascular disease progression in female Zucker Diabetic Fatty rats occurs via unique mechanisms compared to males. Sci Rep 7:17823
Arnold, Nicholas; Mahmood, Abuzar; Ramdas, Maya et al. (2017) Regulation of the cardioprotective adiponectin and its receptor AdipoR1 by salt. Can J Physiol Pharmacol 95:305-309
Luck, Christian; DeMarco, Vincent G; Mahmood, Abuzar et al. (2017) Differential Regulation of Cardiac Function and Intracardiac Cytokines by Rapamycin in Healthy and Diabetic Rats. Oxid Med Cell Longev 2017:5724046
Nistala, Ravi; Raja, Ahmad; Pulakat, Lakshmi (2017) mTORC1 inhibitors rapamycin and metformin affect cardiovascular markers differentially in ZDF rats. Can J Physiol Pharmacol 95:281-287
Ringling, Rebecca E; Gastecki, Michelle L; Woodford, Makenzie L et al. (2016) Loss of Nlrp3 Does Not Protect Mice from Western Diet-Induced Adipose Tissue Inflammation and Glucose Intolerance. PLoS One 11:e0161939
?lusarz, Anna; Pulakat, Lakshmi (2015) The two faces of miR-29. J Cardiovasc Med (Hagerstown) 16:480-90
Gul, Rukhsana; Mahmood, Abuzar; Luck, Christian et al. (2015) Regulation of cardiac miR-208a, an inducer of obesity, by rapamycin and nebivolol. Obesity (Silver Spring) 23:2251-9
Bender, Shawn B; DeMarco, Vincent G; Padilla, Jaume et al. (2015) Mineralocorticoid receptor antagonism treats obesity-associated cardiac diastolic dysfunction. Hypertension 65:1082-8
Mahmood, Abuzar; Pulakat, Lakshmi (2015) Differential Effects of ?-Blockers, Angiotensin II Receptor Blockers, and a Novel AT2R Agonist NP-6A4 on Stress Response of Nutrient-Starved Cardiovascular Cells. PLoS One 10:e0144824

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