scholarly journals AMPA-Type Glutamate Receptors Associated With Vascular Smooth Muscle Cell Subpopulations in Atherosclerosis and Vascular Injury

2021 ◽  
Vol 8 ◽  
Author(s):  
Alessandro L. Gallina ◽  
Urszula Rykaczewska ◽  
Robert C. Wirka ◽  
April S. Caravaca ◽  
Vladimir S. Shavva ◽  
...  

Objectives and Aims: Vascular smooth muscle cells (VSMCs) are key constituents of both normal arteries and atherosclerotic plaques. They have an ability to adapt to changes in the local environment by undergoing phenotypic modulation. An improved understanding of the mechanisms that regulate VSMC phenotypic changes may provide insights that suggest new therapeutic targets in treatment of cardiovascular disease (CVD). The amino-acid glutamate has been associated with CVD risk and VSMCs metabolism in experimental models, and glutamate receptors regulate VSMC biology and promote pulmonary vascular remodeling. However, glutamate-signaling in human atherosclerosis has not been explored.Methods and Results: We identified glutamate receptors and glutamate metabolism-related enzymes in VSMCs from human atherosclerotic lesions, as determined by single cell RNA sequencing and microarray analysis. Expression of the receptor subunits glutamate receptor, ionotropic, α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic (AMPA)-type subunit 1 (GRIA1) and 2 (GRIA2) was restricted to cells of mesenchymal origin, primarily VSMCs, as confirmed by immunostaining. In a rat model of arterial injury and repair, changes of GRIA1 and GRIA2 mRNA level were most pronounced at time points associated with VSMC proliferation, migration, and phenotypic modulation. In vitro, human carotid artery SMCs expressed GRIA1, and selective AMPA-type receptor blocking inhibited expression of typical contractile markers and promoted pathways associated with VSMC phenotypic modulation. In our biobank of human carotid endarterectomies, low expression of AMPA-type receptor subunits was associated with higher content of inflammatory cells and a higher frequency of adverse clinical events such as stroke.Conclusion: AMPA-type glutamate receptors are expressed in VSMCs and are associated with phenotypic modulation. Patients suffering from adverse clinical events showed significantly lower mRNA level of GRIA1 and GRIA2 in their atherosclerotic lesions compared to asymptomatic patients. These results warrant further mapping of neurotransmitter signaling in the pathogenesis of human atherosclerosis.

2015 ◽  
Vol 35 (suppl_1) ◽  
Author(s):  
Ning Shi ◽  
Xiao-Bing Cui ◽  
Shi-You Chen

Olfactomedin 2 (Olfm2) is a novel regulator for vascular smooth muscle cell (SMC) differentiation, but it is unclear whether Olfm2 is also involved in SMC phenotypic modulation, an important process associated with vascular injury. In this study, we found that Olfm2 was induced during PDGF-BB-induced SMC phenotypic modulation. Olfm2 knockdown attenuated PDGF-BB-induced suppression of SM marker genes including SM myosin heavy chain and SM22α, and also inhibited PDGF-BB-stimulated SMC proliferation and migration. On the other hand, Olfm2 overexpression down-regulated SM markers gene expression, and promoted SMC proliferation marker PCNA expression. Moreover, PDGF-BB slightly induced expression of Runx2, which interfered with the formation of SRF/myocardin ternary complex, but dramatically enhanced SRF-Runx2 interaction, suggesting that certain factors mediate SRF-Runx2 interaction. Indeed, Olfm2 physically interacted with both SRF and Runx2. Blockade of Olfm2 inhibited SRF association with Runx2, leading to increased association between SRF and myocardin, which in turn activated the transcription of SM markers, whereas overexpression of Olfm2 promoted SRF binding to Runx2. These results demonstrated that Olfm2 mediates the interaction between SRF and Runx2, contributing to SMC phenotypic modulation.


Circulation ◽  
2008 ◽  
Vol 118 (suppl_18) ◽  
Author(s):  
Wei Kong ◽  
Li Wang ◽  
Xue Bai ◽  
Bo Liu ◽  
Yi Zhu ◽  
...  

Migration of vascular smooth muscle cells (VSMCs) plays an essential role during vascular development, in response to vascular injury and during atherogenesis. Extensive studies have implicated the importance of extracellular matrix (ECM)-degrading proteinases during VSMCs migration. ADAMTS (a disintegrin and metalloproteinase with thrombospondin motifs), a recently described family of proteinases, is capable of degrading vascular ECM proteins. However, the relevance of ADAMTS family members in cardiovascular disease is poorly understood. In this study, we sought to determine whether ADAMTS-7 is involved in VSMC migration and neointima formation in response to vascular injury. Denudation of rat carotid arteries with a balloon catheter led to an initial decrease of ADAMTS-7 protein level in injured compared with sham-operated arteries within the first 24 hours, followed by a subsequent increase during the 4 to 14 days after injury. In primary VSMCs, the pro-inflammatory cytokine TNF-α increased ADAMTS-7 mRNA level through transcriptional factors nuclear factor-kappa B and AP-1. VSMCs infected with ADAMTS-7 adenovirus (Ad-ADAMTS-7) greatly accelerated their migration and invasion in vitro . Conversely, suppression of ADAMTS-7 expression by small interfering RNA (siRNA) markedly retarded VSMC movement by 50% than that with scramble siRNA. At 7 days after injury, the neointimal area of the vascular wall was sixfold greater in Ad-ADAMTS-7-infected than that in Ad-GFP-infected vessels (3.10±0.88 vs. 0.52±0.28 ×10 4 μm 2 , n=8 per group, P <0.05). By contrast, perivascular administration of ADAMTS-7 siRNA, but not scramble siRNA to injured arteries resulted in prolonged ADAMTS-7 silencing and diminished neointimal thickening without affecting medial areas. This inhibitory effect was sustained up to 14 days after injury. As well, ADAMTS-7 mediated degradation of the vascular ECM cartilage oligomeric matrix protein (COMP) in injured vessels, which might facilitate VSMC migration and neointimal thickening. ADAMTS-7 directs VSMC migration and neointima formation and therefore may serve as a novel therapeutic target for vascular restenosis and atherogenesis.


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