Under the support of the previous grant, we tested the hypothesis that PKC?, an important stress regulator, contributes to smooth muscle cell depletion and vascular inflammation during aneurysm development. Using a combination of genetic, molecular, and pharmacological approaches, we demonstrated the essential role of PKC? in regulating vascular smooth muscle cell (SMC) apoptosis in aneurysm. Unexpectedly, we also discovered a novel connection between PKC? and necroptosis, a form of programmed necrosis first described a decade ago. Receptor-interacting protein kinase 3 (RIP3) and its partner RIP1 are among the few identified mediators of necroptosis, underscoring the significance of positioning PKC? within this pathway. We demonstrated that in human aneurysm tissue, SMC levels of both PKC? and RIP3 was upregulated. In mice, gene deletion of either PKC? (Prkcd-/-) or RIP3 (Rip3-/-) produced an aneurysm-resistant phenotype associated with preserved SMCs and diminished inflammation. In preliminary studies, we showed that PKC? regulates Rip3 gene transcription in aortic SMCs, a novel finding highly expected to advance RIP3 biology. The robust aneurysm-protective phenotype of Rip3-/- and Rip3+/- motivated a chemical library screening which led to the discovery of a class of potent and safe RIP3 inhibitors. In this renewal application, we hypothesize that PKC?- STAT3 signaling is a determinant of SMC Rip3 expression and that inhibition of RIP3 may attenuate growth of pre-existing aneurysms. Our objectives for the next 5 years include 1) to determine the molecular mechanism underlying PKC?-mediated Rip3 gene expression in aneurysmal aortic wall, 2) to establish a more comprehensive necroptosis signaling network in aortic SMCs, and 3) to use the new RIP3 inhibitor to block disease progression of pre-existing aneurysms in mice. Two independent specific aims are proposed.
In Specific Aim 1, we plan to prove the critical role of STAT3 in PKC?'s regulation of Rip3 by rescuing Prkcd-/- SMCs with a constitutively active STAT3. Next, we will determine whether STAT3 Serine727, a less studied regulatory mechanism, is phosphorylated in aneurysm tissue via a PKC?-dependent mechanism. Mechanistically, we postulate that STAT3 regulates Rip3 gene transcription through a downstream cis-element. We will test this hypothesis using cutting edge technologies such as Chip-sequencing and CRISPR/Cas9-mediated gene editing.
Specific Aim 2 is both basic and translational, with a goal to address the current knowledge gaps in necroptosis biology and to advance therapeutic development for aneurysm. We will utilize the new RIP3 inhibitors to study necroptosis, addressing the relationship between RIP3 kinase inhibition and apoptosis induction and identifying new RIP3 substrates specific to SMCs. In addition to hypothesis-driven approaches, we will employ phospho- proteomics to unbiasedly identify new components of the necroptosis pathway unique to SMCs. Finally, we will prove in vivo that the new RIP3 inhibitors can reverse SMC depletion, tissue destruction and inflammation when administered to mice with pre-existing aneurysmal dilations. Information produced by the proposed studies is likely to have a high impact on the understanding of programmed necrosis as well as aneurysm therapeutic development.

Public Health Relevance

Abdominal aortic aneurysm is the 8th leading cause of death and disability in the United States. In this project, we will study the molecular and cellular mechanisms that cause an aneurysm to progressively grow and eventually rupture, and to test a group of cell death inhibitors we identified for their abilities to treat aneurysm.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
5R01HL088447-06
Application #
9468425
Study Section
Atherosclerosis and Inflammation of the Cardiovascular System Study Section (AICS)
Program Officer
Tolunay, Eser
Project Start
2010-12-15
Project End
2021-03-31
Budget Start
2018-04-01
Budget End
2019-03-31
Support Year
6
Fiscal Year
2018
Total Cost
Indirect Cost
Name
University of Wisconsin Madison
Department
Surgery
Type
Schools of Medicine
DUNS #
161202122
City
Madison
State
WI
Country
United States
Zip Code
53715
Gupta, Kartik; Phan, Noel; Wang, Qiwei et al. (2018) Necroptosis in cardiovascular disease - a new therapeutic target. J Mol Cell Cardiol 118:26-35
Wang, Qiwei; Zhou, Ting; Liu, Zhenjie et al. (2017) Inhibition of Receptor-Interacting Protein Kinase 1 with Necrostatin-1s ameliorates disease progression in elastase-induced mouse abdominal aortic aneurysm model. Sci Rep 7:42159
Park, Arick C; Phan, Noel; Massoudi, Dawiyat et al. (2017) Deficits in Col5a2 Expression Result in Novel Skin and Adipose Abnormalities and Predisposition to Aortic Aneurysms and Dissections. Am J Pathol 187:2300-2311
Ren, Jun; Liu, Zhenjie; Wang, Qiwei et al. (2016) Andrographolide Ameliorates Abdominal Aortic Aneurysm Progression by Inhibiting Inflammatory Cell Infiltration through Downregulation of Cytokine and Integrin Expression. J Pharmacol Exp Ther 356:137-47
Wang, Qiwei; Liu, Zhenjie; Ren, Jun et al. (2015) Receptor-interacting protein kinase 3 contributes to abdominal aortic aneurysms via smooth muscle cell necrosis and inflammation. Circ Res 116:600-11
Liu, Zhenjie; Wang, Qiwei; Ren, Jun et al. (2015) Murine abdominal aortic aneurysm model by orthotopic allograft transplantation of elastase-treated abdominal aorta. J Vasc Surg 62:1607-14.e2
Liu, Zhenjie; Morgan, Stephanie; Ren, Jun et al. (2015) Thrombospondin-1 (TSP1) contributes to the development of vascular inflammation by regulating monocytic cell motility in mouse models of abdominal aortic aneurysm. Circ Res 117:129-41
Ren, Jun; Wang, Qiwei; Morgan, Stephanie et al. (2014) Protein kinase C-? (PKC?) regulates proinflammatory chemokine expression through cytosolic interaction with the NF-?B subunit p65 in vascular smooth muscle cells. J Biol Chem 289:9013-26
Wang, Qiwei; Ren, Jun; Morgan, Stephanie et al. (2014) Monocyte chemoattractant protein-1 (MCP-1) regulates macrophage cytotoxicity in abdominal aortic aneurysm. PLoS One 9:e92053
Yamanouchi, Dai; Morgan, Stephanie; Stair, Colin et al. (2012) Accelerated aneurysmal dilation associated with apoptosis and inflammation in a newly developed calcium phosphate rodent abdominal aortic aneurysm model. J Vasc Surg 56:455-61

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