scholarly journals Up-regulated MCPIP1 in abdominal aortic aneurysm is associated with vascular smooth muscle cell apoptosis and MMPs production

2019 ◽  
Vol 39 (11) ◽  
Author(s):  
Ming Xue ◽  
Gang Li ◽  
Dan Li ◽  
Zhu Wang ◽  
Lei Mi ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Abdominal Aortic Aneurysm ◽  
Aortic Aneurysm ◽  
Vascular Smooth Muscle ◽  
Interleukin 1 ◽  
Ang Ii ◽  
Monocyte Chemotactic Protein ◽  
Abdominal Aortic ◽  
Chemotactic Protein ◽  
Proliferation And Apoptosis

Abstract Abdominal aortic aneurysm (AAA) is often clinically silent before rupture characterized by extensive vascular inflammation and degenerative elasticity of aortic wall. Monocyte chemotactic protein-induced protein-1 (MCPIP1) exhibits anti-infllammatory and pro-apoptotic effects involved in atherogenesis. However, little is known about the expression and the contribution of MCPIP1 in AAA. In the present study, we collected clinical AAA specimens and constructed AAA mice model through Ang-II infusion, and found apparently increased MCPIP1 expression and severe inflammatory infiltration in AAA aortic membrane as evidenced by elevated levels of monocyte chemotactic protein 1 (MCP-1), interleukin 1 β (IL-1β) and NF-κB, as well as HE staining. The elasticity of aortic tunica media was impaired along with multiple apoptosis of vascular smooth muscle cells (VSMCs) in Ang-II-induced aneurysmal mouse. In vitro Ang-II administration of VSMCs induced MCPIP1 expression, accompanied by up-regulation of matrix metalloproteinase (MMP) 2 (MMP-2) and MMP-9, as well as enhancement of VSMCs proliferation and apoptosis, which may cause damage of intima–media elasticity. Silencing MCPIP1 reversed above effects to further restore the balance of proliferation and apoptosis in VSMCs. Overall, our data indicated that up-regulation of MCPIP1 may become a promising candidate for the diagnosis of AAA, and specific knockdown of MCPIP1 in VSMCs could inhibit VSMCs apoptosis and down-regulate MMPs to maintain vascular wall elasticity. Therefore, knockdown of MCPIP1 may serve as a potential target for gene therapy of AAA.

scholarly journals SM22α Loss Contributes to Apoptosis of Vascular Smooth Muscle Cells via Macrophage-Derived circRasGEF1B

2021 ◽  
Vol 2021 ◽  
pp. 1-20
Author(s):  
Pin Lv ◽  
Ya-Juan Yin ◽  
Peng Kong ◽  
Li Cao ◽  
Hao Xi ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Abdominal Aortic Aneurysm ◽  
Aortic Aneurysm ◽  
Vascular Smooth Muscle ◽  
Inflammatory Cell ◽  
Activated Macrophages ◽  
Abdominal Aortic ◽  
Specific Manner ◽  
Higher Sensitivity

Vascular smooth muscle cell (VSMC) apoptosis is a major defining feature of abdominal aortic aneurysm (AAA) and mainly caused by inflammatory cell infiltration. Smooth muscle (SM) 22α prevents AAA formation through suppressing NF-κB activation. However, the role of SM22α in VSMC apoptosis is controversial. Here, we identified that SM22α loss contributed to apoptosis of VSMCs via activation of macrophages. Firstly, deficiency of SM22α enhanced the interaction of VSMCs with macrophages. Macrophages were retained and activated by Sm22α-/- VSMCs via upregulating VCAM-1 expression. The ratio of apoptosis was increased by 1.62-fold in VSMCs treated with the conditional media (CM) from activated RAW264.7 cells, compared to that of the control CM ( P < 0.01 ), and apoptosis of Sm22α-/- VSMCs was higher than that of WT VSMCs ( P < 0.001 ). Next, circRasGEF1B from activated macrophages was delivered into VSMCs promoting ZFP36 expression via stabilization of ZFP36 mRNA. Importantly, circRasGEF1B, as a scaffold, guided ZFP36 to preferentially bind to and decay Bcl-2 mRNA in a sequence-specific manner and triggered apoptosis of VSMCs, especially in Sm22α-/- VSMCs. These findings reveal a novel mechanism by which the circRasGEF1B-ZFP36 axis mediates macrophage-induced VSMC apoptosis via decay of Bcl-2 mRNA, whereas Sm22α-/- VSMCs have a higher sensitivity to apoptosis.

scholarly journals Excessive EP4 Signaling in Smooth Muscle Cells Induces Abdominal Aortic Aneurysm by Amplifying Inflammation

2020 ◽  
Vol 40 (6) ◽  
pp. 1559-1573
Author(s):  
Taro Hiromi ◽  
Utako Yokoyama ◽  
Daisuke Kurotaki ◽  
Al Mamun ◽  
Ryo Ishiwata ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Abdominal Aortic Aneurysm ◽  
Aortic Aneurysm ◽  
Smooth Muscle Cells ◽  
Muscle Cells ◽  
Macrophage Infiltration ◽  
Prostaglandin E ◽  
Ang Ii ◽  
Inflammatory Monocyte ◽  
Abdominal Aortic

Objective: Excessive prostaglandin E 2 production is a hallmark of abdominal aortic aneurysm (AAA). Enhanced expression of prostaglandin E 2 receptor EP4 (prostaglandin E receptor 4) in vascular smooth muscle cells (VSMCs) has been demonstrated in human AAAs. Although moderate expression of EP4 contributes to vascular homeostasis, the roles of excessive EP4 in vascular pathology remain uncertain. We aimed to investigate whether EP4 overexpression in VSMCs exacerbates AAAs. Approach and Results: We constructed mice with EP4 overexpressed selectively in VSMCs under an SM22α promoter (EP4-Tg). Most EP4-Tg mice died within 2 weeks of Ang II (angiotensin II) infusion due to AAA, while nontransgenic mice given Ang II displayed no overt phenotype. EP4-Tg developed much larger AAAs than nontransgenic mice after periaortic CaCl 2 application. In contrast, EP4 fl/+ ;SM22-Cre;ApoE −/ − and EP4 fl/+ ;SM22-Cre mice, which are EP4 heterozygous knockout in VSMCs, rarely exhibited AAA after Ang II or CaCl 2 treatment, respectively. In Ang II–infused EP4-Tg aorta, Ly6C hi inflammatory monocyte/macrophage infiltration and MMP-9 (matrix metalloprotease-9) activation were enhanced. An unbiased analysis revealed that EP4 stimulation positively regulated the genes binding cytokine receptors in VSMCs, in which IL (interleukin)-6 was the most strongly upregulated. In VSMCs of EP4-Tg and human AAAs, EP4 stimulation caused marked IL-6 production via TAK1 (transforming growth factor-β–activated kinase 1), NF-κB (nuclear factor-kappa B), JNK (c-Jun N-terminal kinase), and p38. Inhibition of IL-6 prevented Ang II–induced AAA formation in EP4-Tg. In addition, EP4 stimulation decreased elastin/collagen cross-linking protein LOX (lysyl oxidase) in both human and mouse VSMCs. Conclusions: Dysregulated EP4 overexpression in VSMCs promotes inflammatory monocyte/macrophage infiltration and attenuates elastin/collagen fiber formation, leading to AAA exacerbation.

scholarly journals Vascular Smooth Muscle Cells in Aortic Aneurysm: From Genetics to Mechanisms

2021 ◽  
Author(s):  
Haocheng Lu ◽  
Wa Du ◽  
Lu Ren ◽  
Milton H. Hamblin ◽  
Richard C. Becker ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Abdominal Aortic Aneurysm ◽  
Aortic Aneurysm ◽  
Vascular Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Vascular Smooth Muscle Cells ◽  
Thoracic Aortic Aneurysm ◽  
Muscle Cells ◽  
Abdominal Aortic ◽  
Aneurysm Development

Abstract Aortic aneurysm, including thoracic aortic aneurysm and abdominal aortic aneurysm, is the second most prevalent aortic disease following atherosclerosis, representing the ninth‐leading cause of death globally. Open surgery and endovascular procedures are the major treatments for aortic aneurysm. Typically, thoracic aortic aneurysm has a more robust genetic background than abdominal aortic aneurysm. Abdominal aortic aneurysm shares many features with thoracic aortic aneurysm, including loss of vascular smooth muscle cells (VSMCs), extracellular matrix degradation and inflammation. Although there are limitations to perfectly recapitulating all features of human aortic aneurysm, experimental models provide valuable tools to understand the molecular mechanisms and test novel therapies before human clinical trials. Among the cell types involved in aortic aneurysm development, VSMC dysfunction correlates with loss of aortic wall structural integrity. Here, we discuss the role of VSMCs in aortic aneurysm development. The loss of VSMCs, VSMC phenotypic switching, secretion of inflammatory cytokines, increased matrix metalloproteinase activity, elevated reactive oxygen species, defective autophagy, and increased senescence contribute to aortic aneurysm development. Further studies on aortic aneurysm pathogenesis and elucidation of the underlying signaling pathways are necessary to identify more novel targets for treating this prevalent and clinical impactful disease.

scholarly journals Inducible Depletion of Calpain-2 Mitigates Abdominal Aortic Aneurysm in Mice

2021 ◽  
Author(s):  
Latha Muniappan ◽  
Michihiro Okuyama ◽  
Aida Javidan ◽  
Devi Thiagarajan ◽  
Weihua Jiang ◽  
...  
Keyword(s):  
Extracellular Matrix ◽  
Smooth Muscle ◽  
Abdominal Aortic Aneurysm ◽  
Aortic Aneurysm ◽  
Structural Integrity ◽  
Mesenchymal Cell ◽  
Ang Ii ◽  
Structural Protein ◽  
Abdominal Aortic ◽  
Calpain 2

Objective: Cytoskeletal structural proteins maintain cell structural integrity by bridging extracellular matrix with contractile filaments. During abdominal aortic aneurysm (AAA) development, (1) aortic medial degeneration is associated with loss of smooth muscle cell integrity and (2) fibrogenic mesenchymal cells mediate extracellular matrix remodeling. Calpains cleave cytoskeletal proteins that maintain cell structural integrity. Pharmacological inhibition of calpains exert beneficial effects on Ang II (angiotensin II)–induced AAAs in LDLR −/− (low-density receptor deficient) mice. Here, we evaluated the functional contribution of fibrogenic mesenchymal cells-derived calpain-2 on (1) cytoskeletal structural protein and extracellular matrix alterations and (2) AAA progression. Approach and Results: Calpain-2 protein and cytoskeletal protein (filamin and talin) fragmentation are significantly elevated in human and Ang II–induced AAAs in mice. To examine the relative contribution of calpain-2 in AAA development, calpain-2 floxed mice in an LDLr −/− background were bred to mice with a tamoxifen-inducible form of Cre under control of either the ubiquitous promoter, chicken β-actin, or fibrogenic mesenchymal cell-specific promoter, Col1α2. Ubiquitous or fibrogenic mesenchymal cell-specific depletion of calpain-2 in mice suppressed Ang II–induced AAAs, filamin/talin fragmentation, while promoting extracellular matrix protein, collagen in the aortas. Calpain-2 silencing in aortic smooth muscle cells or fibroblasts reduced Ang II–induced filamin fragmentation. In addition, silencing of filamin in aortic SMCs significantly reduced collagen protein. Furthermore, calpain-2 deficiency suppressed rupture of established Ang II–induced AAAs in mice. Conclusions: Our studies implicate that calpain-2 deficiency prevents (1) Ang II–induced cytoskeletal structural protein fragmentation and AAA development and (2) stabilize and suppress rupture of established AAAs in mice.

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