Inflammation plays an essential role in vascular injury and repair. Mononuclear phagocytes are important contributors in these processes, in part via adhesive interactions and secretion of pro-inflammatory cytokines. The anti-inflammatory cytokine IL-10 suppresses such responses via deactivation of monocytes/macrophages and repression of inflammatory cytokine expression. The mechanisms of IL-10 suppressive action are, however, incompletely characterized. Our recently published data and follow-up preliminary studies indicate that systemic IL-10 treatment following carotid artery denudation in mice blunts inflammatory cell infiltration, arterial TNF expression and intimal hyperplasia while augmenting re- endothelialization. At molecular level, IL-10-mediated suppression occurs via enhanced de-stabilization of mRNA in A+U rich elements dependent manner. IL-10 inhibits the expression of mRNA stabilizing protein HuR and its ability to bind to TNF-ARE sequences. This proposal will focus our efforts upon reconciling our in vitro mechanistic observations to the in vivo physiological models. Specifically we will attempt to: a) elucidating TNF mRNA destabilization as underlying mechanism of IL-10 sensitivity in vivo, utilizing transgenic mice in which ARE portion of TNF has specifically been deleted (TNFdeltaARE) thereby resulting in significantly elevated TNF levels, b) understanding the molecular events through which IL-10 post- transcriptionally suppresses TNF mRNA stability, specifically IL-10 modulation of trans factors/proteins binding to sequences controlling mRNA half-life, and c) the implication of these events on attenuation of neointimal thickening after arterial injury in mouse models of carotid artery denudation. Our central hypothesis is that loss of TNF-ARE in vivo attenuates the inhibitory effect of IL-10 on TNF expression resulting in enhanced injury-induced arterial inflammation and neointimal hyperplasia. This proposal will test hypotheses organized according to the following 3 specific aims: 1) Determine the role of TNF-ARE binding proteins as downstream target of IL-10 and elucidate signaling mechanisms involved in IL-10- mediated TNF mRNA instability;2) Determine the effect of the loss of IL-10 on post-injury intimal hyperplasia in IL-10 deficient mice;and 3) Establish the requirement of intact TNF-ARE for IL-10 inhibition of intimal hyperplasia and inhibition of TNF mRNA stability, in vivo in TNFdeltaARE mice. Because IL-10 function and signaling are important components for control of inflammatory response, understanding the molecular mechanisms of inflammatory gene regulation by IL-10 in proposed physiologically relevant mouse models may provide insights necessary to develop strategies for modulating vascular repair in restenosis and other accelerated arteriopathies, including transplant vasculopathy and vein graft hyperplasia.

Public Health Relevance

The opening of clogged blood vessels by balloon angioplasty relieves the symptoms of heart disease, however, the procedure is compromised by re-narrowing of the cleared arteries (restenosis) within a year of the procedure. Given that over 1.2 million such procedures are done in the US alone, it is significant health and cost issue. This projects aims to understand the mechanisms of restenosis and thereby potentially identify ways and means to treat this significant health problem.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
5R01HL091983-02
Application #
7802908
Study Section
Vascular Cell and Molecular Biology Study Section (VCMB)
Program Officer
Tolunay, Eser
Project Start
2009-05-01
Project End
2013-04-30
Budget Start
2010-05-11
Budget End
2011-04-30
Support Year
2
Fiscal Year
2010
Total Cost
$381,250
Indirect Cost
Name
Northwestern University at Chicago
Department
Internal Medicine/Medicine
Type
Schools of Medicine
DUNS #
005436803
City
Chicago
State
IL
Country
United States
Zip Code
60611
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Sasi, Sharath P; Yan, Xinhua; Zuriaga-Herrero, Marian et al. (2017) Different Sequences of Fractionated Low-Dose Proton and Single Iron-Radiation-Induced Divergent Biological Responses in the Heart. Radiat Res 188:191-203
Srikanth Garikipati, Venkata Naga; Kishore, Raj (2017) Young Hearts Run Free: Therapeutic Potential of Neonatal Human Cardiac Progenitor Cells Secretome. Circ Res 120:751-752
Verma, Suresh K; Garikipati, Venkata N S; Krishnamurthy, Prasanna et al. (2017) Interleukin-10 Inhibits Bone Marrow Fibroblast Progenitor Cell-Mediated Cardiac Fibrosis in Pressure-Overloaded Myocardium. Circulation 136:940-953
Cheng, Zhongjian; Garikipati, Venkata Naga Srikanth; Nickoloff, Emily et al. (2016) Restoration of Hydrogen Sulfide Production in Diabetic Mice Improves Reparative Function of Bone Marrow Cells. Circulation 134:1467-1483
Kishore, Raj; Garikipati, Venkata Naga Srikanth; Gumpert, Anna (2016) Tiny Shuttles for Information Transfer: Exosomes in Cardiac Health and Disease. J Cardiovasc Transl Res 9:169-75
Kishore, Raj; Khan, Mohsin (2016) More Than Tiny Sacks: Stem Cell Exosomes as Cell-Free Modality for Cardiac Repair. Circ Res 118:330-43
Verma, Suresh K; Garikipati, Venkata Naga Srikanth; Krishnamurthy, Prasanna et al. (2016) IL-10 Accelerates Re-Endothelialization and Inhibits Post-Injury Intimal Hyperplasia following Carotid Artery Denudation. PLoS One 11:e0147615
Jeyabal, Prince; Thandavarayan, Rajarajan A; Joladarashi, Darukeshwara et al. (2016) MicroRNA-9 inhibits hyperglycemia-induced pyroptosis in human ventricular cardiomyocytes by targeting ELAVL1. Biochem Biophys Res Commun 471:423-9
Kishore, Raj; Krishnamurthy, Prasanna; Garikipati, Venkata Naga Srikanth et al. (2015) Interleukin-10 inhibits chronic angiotensin II-induced pathological autophagy. J Mol Cell Cardiol 89:203-13

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