scholarly journals MLKL and CaMKII Are Involved in RIPK3-Mediated Smooth Muscle Cell Necroptosis

Cells ◽  
2021 ◽  
Vol 10 (9) ◽  
pp. 2397
Author(s):  
Ting Zhou ◽  
Elise DeRoo ◽  
Huan Yang ◽  
Amelia Stranz ◽  
Qiwei Wang ◽  
...  

Receptor interacting protein kinase 3 (RIPK3)-mediated smooth muscle cell (SMC) necroptosis has been shown to contribute to the pathogenesis of abdominal aortic aneurysms (AAAs). However, the signaling steps downstream from RIPK3 during SMC necroptosis remain unknown. In this study, the roles of mixed lineage kinase domain-like pseudokinase (MLKL) and calcium/calmodulin-dependent protein kinase II (CaMKII) in SMC necroptosis were investigated. We found that both MLKL and CaMKII were phosphorylated in SMCs in a murine CaCl2-driven model of AAA and that Ripk3 deficiency reduced the phosphorylation of MLKL and CaMKII. In vitro, mouse aortic SMCs were treated with tumor necrosis factor α (TNFα) plus Z-VAD-FMK (zVAD) to induce necroptosis. Our data showed that both MLKL and CaMKII were phosphorylated after TNFα plus zVAD treatment in a time-dependent manner. SiRNA silencing of Mlkl-diminished cell death and administration of the CaMKII inhibitor myristoylated autocamtide-2-related inhibitory peptide (Myr-AIP) or siRNAs against Camk2d partially inhibited necroptosis. Moreover, knocking down Mlkl decreased CaMKII phosphorylation, but silencing Camk2d did not affect phosphorylation, oligomerization, or trafficking of MLKL. Together, our results indicate that both MLKL and CaMKII are involved in RIPK3-mediated SMC necroptosis, and that MLKL is likely upstream of CaMKII in this process.

1997 ◽  
Vol 78 (02) ◽  
pp. 880-886 ◽  
Author(s):  
Monique J Wijnberg ◽  
Paul H A Quax ◽  
Nancy M E Nieuwenbroek ◽  
Jan H Verheijen

SummaryThe plasminogen activation system is thought to be important in cell migration processes. A role for this system during smooth muscle cell migration after vascular injury has been suggested from several animal studies. However, not much is known about its involvement in human vascular remodelling. We studied the involvement of the plasminogen activation system in human smooth muscle cell migration in more detail using an in vitro wound assay and a matrix invasion assay. Inhibition of plasmin activity or inhibition of urokinase-type plasminogen activator (u-PA) activity resulted in approximately 40% reduction of migration after 24 h in the wound assay and an even stronger reduction (70-80%) in the matrix invasion assay. Migration of smooth muscle cells in the presence of inhibitory antibodies against tissue-type plasminogen activator (t-PA) was not significantly reduced after 24 h, but after 48 h a 30% reduction of migration was observed, whereas in the matrix invasion assay a 50% reduction in invasion was observed already after 24 h. Prevention of the interaction of u-PA with cell surface receptors by addition of soluble u-PA receptor or α2-macroglobulin receptor associated protein (RAP) to the culture medium, resulted in a similar inhibition of migration and invasion. From these results it can be concluded that both u-PA and t-PA mediated plasminogen activation can contribute to in vitro human smooth muscle cell migration and invasion. Furthermore, the interaction between u-PA and its cell surface receptor appears also to be involved in this migration and invasion process. The inhibitory effects on migration and invasion by the addition of RAP suggests an involvement of a RAP sensitive receptor of the LDL receptor family, possibly the LDL-receptor related protein (LRP) and/or the VLDL receptor.


2001 ◽  
Vol 711 ◽  
Author(s):  
Derick C. Miller ◽  
Anil Thapa ◽  
Karen M. Haberstroh ◽  
Thomas J. Webster

ABSTRACTBiomaterials that successfully integrate into surrounding tissue should match not only the tissue's mechanical properties, but also the dimensions of the associated nano-structured extra-cellular matrix (ECM) components. The goal of this research was to use these ideals to develop a synthetic, nano-structured, polymeric biomaterial that has cytocompatible and mechanical behaviors similar to that of natural vascular tissue. In a novel manner, poly-lactic acid/polyglycolic acid (PLGA) (50/50 wt.% mix) and polyurethane were separately synthesized to possess a range of fiber dimensions in the micron and nanometer regime. Preliminary results indicated that decreasing fiber diameter on both PLGA and PU enhanced arterial smooth muscle cell adhesion; specifically, arterial smooth muscle cell adhesion increased 23% when PLGA fiber dimensions decreased from 500 to 50 nm and increased 76% on nano-structured, compared to conventional structured, polyurethane. However, nano-structured PLGA decreased endothelial cell adhesion by 52%, whereas adhesion of these same cells was increased by 50% on polyurethane. For these reasons, the present in vitro study provides the first evidence that polymer fiber dimensions can be used to selectively control cell functions for vascular prosthesis.


2016 ◽  
Vol 36 (suppl_1) ◽  
Author(s):  
Mengxue Zhang ◽  
Bowen Wang ◽  
Craig Kent ◽  
Lian-Wang Guo

Introduction: Intimal hyperplasia (IH) occurs primarily due to vascular smooth muscle cell (SMC) transformation from quiescent to pathogenic phenotypes (e.g. proliferation and inflammation). Identification and effective targeting of key epigenetic factors governing SMC pathogenic transformation may lead to novel therapeutic methods for prevention of IH. We previously found that globally blocking the bromo- and extra-terminal (BET) epigenetic “reader” family abrogated SMC phenotype transformation and IH. We further investigated the functions of the two BET bromodomains (Bromo1 and Bromo2). Hypothesis: Bromo1 and Bromo2 play different roles in SMC pathogenic transformation. Methods and Results: We pre-treated rat primary aortic SMCs (for 2h) with Olinone or RVX208, inhibitors specific for Bromo1 and Bromo2 respectively, and then stimulated SMC phenotype transformation. Whereas RVX208 abrogated PDGF-BB-stimulated SMC proliferation (BrdU assay) in a dose dependent manner, Olinone enhanced SMC proliferation at high concentrations (>20 μM). RVX208 at 50 μM reduced TNFα-induced SMC inflammation (MCP-1 ELISA) by 80%,but Olinone at the same concentration slightly increased MCP-1. Furthermore, whereas RVX208 abolished PDGF-BB or TNFα-induced STAT3 phosphorylation (Western blotting), Olinone slightly increased phospho-STAT3. Conclusions: Our results reveal that blocking two BET bromodomains respectively produces distinct effects on SMC phenotype transformation, suggesting their differential epigenetic functions. Further elucidation of the underlying molecular mechanisms should contribute to precise targeting of the BET family for optimal mitigation of IH.


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