Abstract 169: Smad3 Drives Cross-Talk Between TGFß and Wnt/ß-Catenin Signaling Pathways in Smooth Muscle Cells

2014 ◽  
Vol 34 (suppl_1) ◽  
Author(s):  
Daniel M DiRenzo ◽  
Xu Dong Shi ◽  
Lian-Wang Guo ◽  
K Craig Kent

Restenosis (neo-intimal hyperplasia) occurs in approximately 25-50% of patients undergoing arterial interventions, primarily due to the proliferation and migration of arterial smooth muscle cells (SMCs) into the peri-luminal area. Recently, Wnt/β-catenin signaling has been shown to promote SMC proliferation and enhance neo-intimal hyperplasia but its mechanism of activation is unclear. Interestingly, Wnt/β-catenin has been shown to be activated by TGFβ in mesenchymal stem cells and fibroblasts. We have shown that TGFβ and its downstream signaling protein, Smad3, are upregulated following vascular injury and that Smad3 overexpressing SMCs display enhanced proliferation, migration, and neo-intimal hyperplasia. These results led us to hypothesize that TGFβ, through Smad3, activates Wnt/β-catenin to regulate SMC behavior following arterial injury . In primary rat SMCs, TGFβ (5ng/mL) led to β-catenin activation and relocalization from the plasma membrane to the cytoplasm / nucleus within 24 hours. Furthermore, qRT-PCR results demonstrated that expression of Wnt11 (22 fold) and Wnt9a (3.9 fold) were significantly upregulated after 24 hours of TGFβ stimulation (p<0.05, n=3). In addition, 24 hours of TGFβ stimulation in SMCs overexpressing Smad3 (TGFβ/Smad3) further enhanced the gene expression of Wnt11 (>300 fold) and Wnt9a (14 fold) and also stimulated significant increases in Wnt2b (41 fold), Wnt5a (2.9 fold), and Wnt4 (3.2 fold) (p<0.05, n=3) as measured by qRT-PCR. Western blot results demonstrated that the combined TGFβ/Smad3 stimulation increased β-catenin protein levels, suggesting that TGFβ activates canonical Wnt signaling leading to stabilization of β-catenin protein. In normal rat carotid arteries, β-catenin protein was undetectable via immunohistochemistry but could be seen in SMCs of the vessel media at 3 days post-balloon angioplasty and in neo-intimal cells at 7 and 14 days. Smad3 was also expressed in neo-intimal cells at 7 and 14 days post-angioplasty suggesting that TGFβ, through Smad3, is responsible for Wnt/β-Catenin activation during vascular injury. In conclusion, this work describes a novel cross-talk in SMCs between TGFβ and Wnt signaling which may provide a viable target for future anti-restenotic treatments.

Author(s):  
Yung-Chun Wang ◽  
Dunpeng Cai ◽  
Xiao-Bing Cui ◽  
Ya-Hui Chuang ◽  
William P. Fay ◽  
...  

Objective: The objective of this study is to determine the role of JAK3 (Janus kinase 3) in reendothelialization after vascular injury. Methods and Results: By using mouse carotid artery wire injury and rat balloon injury model, we found that JAK3 regulates reendothelialization and endothelial cell proliferation after vascular injury. JAK3 and phospho-JAK3 levels were increased in neointimal smooth muscle cells in response to vascular injury in mice. JAK3 deficiency dramatically attenuated the injury-induced intimal hyperplasia in carotid arteries of both male and female mice. Importantly, JAK3 deficiency caused an increased rate of reendothelialization following mechanical injury. Likewise, knockdown of JAK3 in medial smooth muscle cells elicited an accelerated reendothelialization with reduced intimal hyperplasia following balloon injury in rat carotid arteries. Interestingly, knockdown of JAK3 restored the expression of smooth muscle cell contractile protein smooth muscle α-actin in injury-induced intimal smooth muscle cells while increased the proliferating endothelial cells in the intima area. Conclusions: Our results demonstrate a novel role of JAK3 in the regeneration of endothelium after vascular injury, which may provide a new strategy to enhance reendothelialization while suppressing neointimal formation for effective vascular repair from injury.


2004 ◽  
Vol 287 (5) ◽  
pp. H2201-H2208 ◽  
Author(s):  
Yingzi Chang ◽  
Daming Zhuang ◽  
Chunxiang Zhang ◽  
Aviv Hassid

Migration and proliferation of vascular smooth muscle cells are key events in injury-induced neointima formation. Several growth factors and ANG II are thought to be involved in neointima formation. A recent report indicated that vascular injury is associated with increased mRNA levels of protein tyrosine phosphatase (PTP)-1B (PTP-1B). In the present study, we tested the following hypotheses: 1) rat carotid artery injury induces the expression of PTP-1B, Src homology-2 domain phosphatase (SHP-2), and PTP-proline, glutamate, serine, and threonine sequence (PEST) protein; and 2) polypeptide growth factors as well as ANG II increase the levels of tyrosine phosphatases in cultured rat aortic smooth muscle cells. We found that vascular injury induced by balloon catheter increases the protein levels of aforementioned phosphatases and that these effects occur in a PTP specific, as well as temporally and regionally specific, manner. Moreover, treatment of cultured primary rat aortic smooth muscle cells with PDGF or bFGF, but not with IGF1, EGF, or ANG II, increases PTP-1B, SHP-2, and PTP-PEST protein levels. These results suggest that increased PDGF and bFGF levels, occurring after vascular injury, may induce expression of several PTPs.


Circulation ◽  
2001 ◽  
Vol 104 (12) ◽  
pp. 1407-1412 ◽  
Author(s):  
Masaaki Miyata ◽  
Sadatoshi Biro ◽  
Hiroshi Kaieda ◽  
Hideyuki Eto ◽  
Koji Orihara ◽  
...  

2011 ◽  
Vol 15 (8) ◽  
pp. 1695-1702 ◽  
Author(s):  
Guanghong Jia ◽  
Anshu Aggarwal ◽  
Amanuel Yohannes ◽  
Deepak M. Gangahar ◽  
Devendra K. Agrawal

2000 ◽  
Vol 279 (1) ◽  
pp. C248-C256 ◽  
Author(s):  
Liu Hua Wei ◽  
Aaron T. Jacobs ◽  
Sidney M. Morris ◽  
Louis J. Ignarro

The objectives of this study were to determine whether rat aortic smooth muscle cells (RASMC) express arginase and to elucidate the possible mechanisms involved in the regulation of arginase expression. The results show that RASMC contain basal arginase I (AI) activity, which is significantly enhanced by stimulating the cells with either interleukin (IL)-4 or IL-13, but arginase II (AII) expression was not detected under any condition studied here. We further investigated the signal transduction pathways responsible for AI induction. AI mRNA and protein levels were enhanced by addition of forskolin (1 μM) and inhibited by H-89 (30 μM), suggesting positive regulation of AI by a protein kinase A pathway. Genistein (10 μg/ml) and sodium orthovanadate (Na3VO4; 10 μM) were used to investigate the role of tyrosine phosphorylation in the control of AI expression. Genistein inhibited, whereas Na3VO4enhanced the induction of AI by IL-4 or IL-13. Along with immunoprecipitation and immunoblot analyses, these data implicate the JAK/STAT6 pathway in AI regulation. Dexamethasone (Dex) and interferon (IFN)-γ were investigated for their effects on AI induction. Dex (1 μM) and IFN-γ (100 U/ml) alone had no effect on basal AI expression in RASMC, but both reduced AI induction by IL-4 and IL-13. In combination, Dex and IFN-γ abolished AI induction by IL-4 and IL-13. Finally, both IL-4 and IL-13 significantly increased RASMC DNA synthesis as monitored by [3H]thymidine incorporation, demonstrating that upregulation of AI is correlated with an increase in cell proliferation. Blockade of AI induction by IFN-γ, H-89, or genistein also blocked the increase in cell proliferation. These observations are consistent with the possibility that upregulation of AI might play an important role in the pathophysiology of vascular disorders characterized by excessive smooth muscle growth.


2011 ◽  
Vol 20 (3) ◽  
pp. e91-e94 ◽  
Author(s):  
Marc Jevon ◽  
Tahera I. Ansari ◽  
Jonathan Finch ◽  
Mustafa Zakkar ◽  
Paul C. Evans ◽  
...  

1997 ◽  
Vol 45 (6) ◽  
pp. 837-846 ◽  
Author(s):  
Johan Thyberg ◽  
Karin Blomgren ◽  
Joy Roy ◽  
Phan Kiet Tran ◽  
Ulf Hedin

Earlier in vitro studies suggest opposing roles of laminin and fibronectin in regulation of differentiated properties of vascular smooth muscle cells. To find out if this may also be the case in vivo, we used immunoelectron microscopy to study the distribution of these proteins during formation of intimal thickening after arterial injury. In parallel, cell structure and content of smooth muscle α-actin was analyzed. The results indicate that the cells in the normal media are in a contractile phenotype with abundant α-actin filaments and an incomplete basement membrane. Within 1 week after endothelial denudation, most cells in the innermost layer of the media convert into a synthetic phenotype, as judged by loss of actin filaments, construction of a large secretory apparatus, and destruction of the basement membrane. Some of these cells migrate through fenestrae in the internal elastic lamina and invade a fibronectin-rich network deposited on its luminal surface. Within another few weeks a thick neointima forms, newly produced matrix components replace the strands of fibronectin, and a basement membrane reappears. Simultaneously, the cells resume a contractile phenotype, recognized by disappearance of secretory organelles and restoration of α-actin filaments. These findings support the notion that laminin and other basement membrane components promote the expression of a differentiated smooth muscle phenotype, whereas fibronectin stimulates the cells to adopt a proliferative and secretory phenotype.


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