During the previous funding cycles of this grant, we showed that 1. Activation of calcineurin-NFAT signaling is required for both receptor tyrosine kinase (RTK) and G protein-coupled receptor (GPCR) agonist-induced vascular smooth muscle cell (VSMC) growth and motility. 2. Blockade of calcineurin-NFAT activation signaling inhibits balloon injury-induced neointima formation. 3. Cyclins such as cyclin D1 and cyclin A2 and pro- inflammatory cytokines such as IL-6 appear to be the NFAT-target genes in mediating RTK and GPCR agonist-induced VSMC growth and motility and injury-induced vascular wall remodeling. 4. NFAT, particularly NFTAc1, also modulates monocyte chemoattractant protein-1 (MCP-1), a potent chemokine-induced human aortic smooth muscle cell (HASMC) growth and motility as well as vascular wall remodeling via cyclin D1- dependent PKN1 and PAK1 activation. Having observed a common role for NFATc1 in vascular wall remodeling in response to various cues, we have decided to identify additional effector molecules of this transcriptional factor and therefore performed a microarray analysis. The microarray analysis identified LIM and cysteine-rich domains 1 (LMCD1)/Dyxin as a highly responsive gene to thrombin and its expression was dependent on NFAT activation. When we searched for its function, we found that it is a transcriptional cofactor and represses GATA6 and promotes cardiac hypertrophy. With these clues in mind, we examined for its function in HASMCs. Surprisingly, we found that LMCD1 plays a role in thrombin-induced migration and proliferation of HASMCs. In addition, we discovered that LMCD1 is required for CDC6 and IL-33 expression. CDC6 is a member of pre-replicative complex (pre-RC) and is essential in loading mini chromosome maintenance (MCM) proteins onto DNA for initiation of replication whereas IL-33 is a pro-inflammatory cytokine. What is more exciting is that LMCD1 interacts with E2F1 and regulates CDC6 and IL-33 expression in response to thrombin. Furthermore, we found that whereas CDC6 expression is required for HASMC replication IL-33 is needed for their motility. Based on these novel discoveries and preliminary findings, we hypothesize that LMCD1 is a target gene of NFATc1 and LMCD1 by modulating CDC6 and IL-33 expression plays an essential role in vascular wall remodeling. To address this major hypothesis, we will test the following three specific aims. SA1: LMCD1 expression by PLC?3-dependent NFATc1 activation is essential for neointima formation. SA2: LMCD1 in combination with E2F1 modulates the pre-RC regulator CDC6 expression in vascular wall remodeling. SA3: LMCD1 in combination with E2F1 enhances the expression of IL-33 in vascular wall remodeling. The observations of the proposed experiments will identify LMCD1 as a master mediator of restenosis and therefore could become a novel target for drug development in controlling this vascular response following angioplasty and stent implantation.

Public Health Relevance

Restenosis is a major complication after percutaneous transluminal coronary angioplasty. The experiments of this proposal will identify LMCD1 as a master mediator of restenosis and therefore could be a novel target for the drug development in suppressing the risk of developing restenosis following angioplasty and stent implantation.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
5R01HL069908-15
Application #
9313750
Study Section
Hypertension and Microcirculation Study Section (HM)
Program Officer
Olive, Michelle
Project Start
2002-04-01
Project End
2020-04-30
Budget Start
2017-05-01
Budget End
2018-04-30
Support Year
15
Fiscal Year
2017
Total Cost
Indirect Cost
Name
University of Tennessee Health Science Center
Department
Physiology
Type
Schools of Medicine
DUNS #
941884009
City
Memphis
State
TN
Country
United States
Zip Code
38103
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