IL-1α-dependent sterile inflammation in atherosclerosis is cell type-dependent and driven by necrotic vascular smooth muscle cells

Calcification of the vessel wall as one structural pathology of aged vessels is associated with high cardiovascular mortality of elderly patients. Aging is linked to chronic sterile inflammation and high burden of reactive oxygen species (ROS), leading to activation of pattern recognition receptors (PRRs) such as Nlrp3 in vascular cells. The current study investigates the role of PRR activation in the calcification of vascular smooth muscle cells (VSMCs). Therefore, in vitro cell culture of primary rat VSMCs and ex vivo aortic stimulations were used to analyze osteogenic, senescence and inflammatory markers via real-time PCR, in situ RNA hybridization, Western Blot, photometric assays and histological staining. Induction of ROS and DNA-damage by doxorubicin induces a shift of VSMC phenotype toward the expression of osteogenic, senescence and inflammatory proteins. Induction of calcification is dependent on Nlrp3 activity. Il-1β as a downstream target of Nlrp3 induces the synthetic, pro-calcifying VSMC phenotype. Inhibition of PRR with subsequent reduction of chronic inflammation might be an interesting target for reduction of calcification of VSMCs, with subsequent reduction of cardiovascular mortality of patients suffering from vessel stiffness.

Download Full-text

Extracellular Vesicles Mediate Communication between Endothelial and Vascular Smooth Muscle Cells

International Journal of Molecular Sciences ◽

10.3390/ijms23010331 ◽

2021 ◽

Vol 23 (1) ◽

pp. 331

Author(s):

Marie Fontaine ◽

Stéphanie Herkenne ◽

Olivier Ek ◽

Alicia Paquot ◽

Amandine Boeckx ◽

...

Keyword(s):

Smooth Muscle ◽

Vascular Smooth Muscle ◽

Smooth Muscle Cells ◽

Extracellular Vesicles ◽

Vascular Smooth Muscle Cells ◽

Muscle Cells ◽

Communication Tool ◽

Cell Type ◽

Cell Functions

The recruitment of pericytes and vascular smooth muscle cells (SMCs) that enwrap endothelial cells (ECs) is a crucial process for vascular maturation and stabilization. Communication between these two cell types is crucial during vascular development and in maintaining vessel homeostasis. Extracellular vesicles (EVs) have emerged as a new communication tool involving the exchange of microRNAs between cells. In the present study, we searched for microRNAs that could be transferred via EVs from ECs to SMCs and vice versa. Thanks to a microRNA profiling experiment, we found that two microRNAs are more exported in each cell type in coculture experiments: while miR-539 is more secreted by ECs, miR-582 is more present in EVs from SMCs. Functional assays revealed that both microRNAs can modulate both cell-type phenotypes. We further identified miR-539 and miR-582 targets, in agreement with their respective cell functions. The results obtained in vivo in the neovascularization model suggest that miR-539 and miR-582 might cooperate to trigger the process of blood vessel coverage by smooth muscle cells in a mature plexus. Taken together, these results are the first to highlight the role of miR-539 and miR-582 in angiogenesis and communication between ECs and SMCs.

Download Full-text

SUN1/2 Are Essential for RhoA/ROCK-Regulated Actomyosin Activity in Isolated Vascular Smooth Muscle Cells

Cells ◽

10.3390/cells9010132 ◽

2020 ◽

Vol 9 (1) ◽

pp. 132

Author(s):

Lauren Porter ◽

Rose-Marie Minaisah ◽

Sultan Ahmed ◽

Seema Ali ◽

Rosemary Norton ◽

...

Keyword(s):

Smooth Muscle ◽

Vascular Smooth Muscle ◽

Smooth Muscle Cells ◽

Vascular Smooth Muscle Cells ◽

Coiled Coil ◽

Muscle Cells ◽

Linc Complex ◽

Cell Type ◽

Rhoa Activity ◽

Predominant Cell Type

Vascular smooth muscle cells (VSMCs) are the predominant cell type in the blood vessel wall. Changes in VSMC actomyosin activity and morphology are prevalent in cardiovascular disease. The actin cytoskeleton actively defines cellular shape and the LInker of Nucleoskeleton and Cytoskeleton (LINC) complex, comprised of nesprin and the Sad1p, UNC-84 (SUN)-domain family members SUN1/2, has emerged as a key regulator of actin cytoskeletal organisation. Although SUN1 and SUN2 function is partially redundant, they possess specific functions and LINC complex composition is tailored for cell-type-specific functions. We investigated the importance of SUN1 and SUN2 in regulating actomyosin activity and cell morphology in VSMCs. We demonstrate that siRNA-mediated depletion of either SUN1 or SUN2 altered VSMC spreading and impaired actomyosin activity and RhoA activity. Importantly, these findings were recapitulated using aortic VSMCs isolated from wild-type and SUN2 knockout (SUN2 KO) mice. Inhibition of actomyosin activity, using the rho-associated, coiled-coil-containing protein kinase1/2 (ROCK1/2) inhibitor Y27632 or blebbistatin, reduced SUN2 mobility in the nuclear envelope and decreased the association between SUN2 and lamin A, confirming that SUN2 dynamics and interactions are influenced by actomyosin activity. We propose that the LINC complex exists in a mechanical feedback circuit with RhoA to regulate VSMC actomyosin activity and morphology.

Download Full-text