Collectivization of Vascular Smooth Muscle Cells via TGF-β–Cadherin-11–Dependent Adhesive Switching

Abstract

Objective-Smooth muscle cells (SMCs) in healthy arteries are arranged as a collective. However, in diseased arteries, SMCs commonly exist as individual cells, unconnected to each other. The purpose of this study was to elucidate the events that enable individualized SMCs to enter into a stable and interacting cell collective. Approach and Results-Human SMCs stimulated to undergo programmed collectivization were tracked by time-lapse microscopy. We uncovered a switch in the behavior of contacting SMCs from semiautonomous motility to cell-cell adherence. Central to the cell-adherent phenotype was the formation of uniquely elongated adherens junctions, up to 60 μm in length, which appeared to strap adjacent SMCs to each other. Remarkably, these junctions contained both N-cadherin and cadherin-11. Ground-state depletion super-resolution microscopy revealed that these hybrid assemblies were comprised of 2 parallel nanotracks of each cadherin, separated by 50 nm. Blocking either N-cadherin or cadherin-11 inhibited collectivization. Cell-cell adhesion and adherens junction elongation were associated with reduced transforming growth factor-β signaling, and exogenous transforming growth factor-β1 suppressed junction elongation via the noncanonical p38 pathway. Imaging of fura-2-loaded SMCs revealed that SMC assemblies displayed coordinated calcium oscillations and cell-cell transmission of calcium waves which, together with increased connexin 43-containing junctions, depended on cadherin-11 and N-cadherin function. Conclusions-SMCs can self-organize, structurally and functionally, via transforming growth factor-β-p38-dependent adhesive switching and a novel adherens junction architecture comprised of hybrid nanotracks of cadherin-11 and N-cadherin. The findings define a mechanism for the assembly of SMCs into networks, a process that may be relevant to the stability and function of blood vessels.

Inhibition of human prostate stromal cell growth and smooth muscle contraction by thalidomide: A novel remedy in LUTS?

“…In parallel to the diminished proliferation rate, we observed, that thalidomide decreased the formation of cell colonies. With plate colony assay, individual cell colonies can be visualized and quantified, 31,32 representing an alternative indicator not only of individual single‐cell proliferation but also of collective growth 47 . However, our findings may be limited due to the fact that we used an immortalized and karyotypically abnormal cell line (WMPY‐1) and, therefore, should be interpreted with care 30 …”

Seno-destructive smooth muscle cells in the ascending aorta of patients with bicuspid aortic valve disease

“…Medial SMCs are central to aortic structure and function. SMCs impart stability to the aorta through their contractile properties, their ability to secrete and assemble ECM fibrils [[6], [7], [8]], and by the firm attachments they form with each other and the ECM [9,10]. Inherently abnormal SMCs can render the aortic wall susceptible to dilation and dissection, a paradigm established by certain genetic and syndromic aortopathies [[11], [12], [13]].…”

High-Content Analysis of MicroRNAs Facilitates the Development of Combinatorial Therapies for Vascular Diseases

“…In order to cluster these targets to the regulatory networks, two online analytic software tools, KOBAS 47 and Metascape 48 , were employed. Combining the results of the two analyses, a number of pathways already connected to the phenotypic switch of VSMC were identified: MAPK 49 , p53 50 , PI3K-AKT 51 , the calcium signaling pathways 52 , regulators of the cell cycle 53 , TGF-beta signaling pathway 54 , or vascular smooth muscle contraction 55 , herewith demonstrating a high quality of our screens. More closely, we looked to the putative regulators of cell adhesion to the extracellular matrix (ECM) due to their crucial role in regulating cell shape and migration.…”