scholarly journals A function for filamentous alpha-smooth muscle actin: retardation of motility in fibroblasts.

1996 ◽  
Vol 134 (1) ◽  
pp. 67-80 ◽  
Author(s):  
L Rønnov-Jessen ◽  
O W Petersen
Keyword(s):  
Smooth Muscle ◽  
Wound Repair ◽  
Smooth Muscle Actin ◽  
Focal Adhesions ◽  
Fibroblast Cell ◽  
Time Lapse ◽  
Alpha Smooth Muscle Actin ◽  
Two Dimensional Gel Electrophoresis ◽  
Knock Out ◽  
Migration Assay

Actins are known to comprise six mammalian isoforms of which beta- and gamma-nonmuscle actins are present in all cells, whereas alpha-smooth muscle (alpha-sm) actin is normally restricted to cells of the smooth muscle lineages. alpha-Sm actin has been found also to be expressed transiently in certain nonmuscle cells, in particular fibroblasts, which are referred to as myofibroblasts. The functional significance of alpha-sm actin in fibroblasts is unknown. However, myofibroblasts appear to play a prominent role in stromal reaction in breast cancer, at the site of wound repair, and in fibrotic reactions. Here, we show that the presence of alpha-sm actin is a signal for retardation of migratory behavior in fibroblasts. Comparison in a migration assay of fibroblast cell strains with and without alpha-sm actin revealed migratory restraint in alpha-sm actin-positive fibroblasts. Electroporation of monoclonal antibody (mAb) 1A4, which recognizes specifically the NH2-terminal Ac-EEED sequence of alpha-sm actin, significantly increased the frequency of migrating cells over that obtained with an unrelated antibody or a mAb against beta-actin. Time-lapse video microscopy revealed migratory rates of 4.8 and 3.0 microns/h, respectively. To knock out the alpha-sm actin protein, several antisense phosphorothioate oligodeoxynucleotide (ODNs) were tested. One of these, 3'UTI, which is complementary to a highly evolutionary conserved 3' untranslated (3'UT) sequence of alpha-sm actin mRNA, was found to block alpha-sm actin synthesis completely without affecting the synthesis of any other proteins as analyzed by two-dimensional gel electrophoresis. Targeting by antisense 3'UTI significantly increased motility compared with the corresponding sense ODN. alpha-Sm actin inhibition also led to the formation of less prominent focal adhesions as revealed by immunofluorescence staining against vinculin, talin, and beta1-integrin. We propose that an important function of filamentous alpha-sm actin is to immobilize the cells.

scholarly journals ELTD1 Activation Induces an Endothelial-EMT Transition to a Myofibroblast Phenotype

2021 ◽  
Vol 22 (20) ◽  
pp. 11293
Author(s):  
Helen Sheldon ◽  
John Alexander ◽  
Esther Bridges ◽  
Lucia Moreira ◽  
Svetlana Reilly ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Smooth Muscle ◽  
Wound Repair ◽  
Network Formation ◽  
Smooth Muscle Actin ◽  
Focal Adhesions ◽  
Enrichment Analysis ◽  
Gene Set Enrichment Analysis ◽  
Immune Response Gene ◽  
Cell Contact

ELTD1 is expressed in endothelial and vascular smooth muscle cells and has a role in angiogenesis. It has been classified as an adhesion GPCR, but as yet, no ligand has been identified and its function remains unknown. To establish its role, ELTD1 was overexpressed in endothelial cells. Expression and consequently ligand independent activation of ELTD1 results in endothelial-mesenchymal transistion (EndMT) with a loss of cell-cell contact, formation of stress fibres and mature focal adhesions and an increased expression of smooth muscle actin. The effect was pro-angiogenic, increasing Matrigel network formation and endothelial sprouting. RNA-Seq analysis after the cells had undergone EndMT revealed large increases in chemokines and cytokines involved in regulating immune response. Gene set enrichment analysis of the data identified a number of pathways involved in myofibroblast biology suggesting that the endothelial cells had undergone a type II EMT. This type of EMT is involved in wound repair and is closely associated with inflammation implicating ELTD1 in these processes.

FAK-mediated Inhibition of Vascular Smooth Muscle Cell Migration by the Tetraspanin CD9

2002 ◽  
Vol 87 (06) ◽  
pp. 1043-1050 ◽  
Author(s):  
Arnaud Scherberich ◽  
Grégory Giannone ◽  
Elisabeth Perennou ◽  
Kenneth Takeda ◽  
Claude Boucheix ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Vascular Smooth Muscle ◽  
Focal Adhesions ◽  
Stress Fiber ◽  
Fiber Formation ◽  
Knock Out ◽  
Migration Assay ◽  
Stress Fiber Formation ◽  
Integrin Clustering ◽  
Stimulation Of

SummaryMigration of vascular smooth muscle cells (SMC) towards the intima is a key event in vascular proliferative diseases. We investigated a potential role for the tetraspanin CD9 in this process in a wound migration assay. Aortic SMC from CD9 knock-out mice had higher migration rates and the presumably stimulatory anti-CD9 antibody ALMA-1 inhibited migration of human SMC. The signaling pathways responsible for this inhibitory effect were investigated. In migrating CD9−/− SMC, stress fiber formation was decreased and focal adhesions were smaller and more diffusely distributed, consistent with an inhibition of integrin clustering. In migrating mouse SMC expressing CD9, focal adhesion kinase (FAK) tyrosine phosphorylation was doubled. No differences in intracellular calcium signaling were observed between CD9+/+ and CD9−/− SMC during migration. We suggest that CD9 inhibits SMC migration by a stimulation of both stress fiber formation and integrin clustering, leading to a stimulation of FAK phosphorylation.

scholarly journals ELTD1 Activation Induces an Endothelial-EMT Transition to a Myofibroblast Phenotype

2021 ◽  
Author(s):  
Helen Sheldon ◽  
John Alexander ◽  
Esther M. Bridges ◽  
Lucia Moreira ◽  
Svetlana Reilly ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Smooth Muscle ◽  
Wound Repair ◽  
Network Formation ◽  
Smooth Muscle Actin ◽  
Focal Adhesions ◽  
Enrichment Analysis ◽  
Gene Set Enrichment Analysis ◽  
Immune Response Gene ◽  
Cell Contact

ELTD1 is expressed in endothelial and vascular smooth muscle cells and has a role in angiogenesis. It has been classified as an adhesion GPCR, but as yet, no ligand has been identified and its function remains unknown. To establish its role, ELTD1 was overexpressed in endothelial cells. Expression and consequently ligand independent activation of ELTD1 results in EndMT with a loss of cell-cell contact, formation of stress fibres and mature focal adhesions and an increased expression of smooth muscle actin. The effect was pro-angiogenic, increasing Matrigel network formation and endothelial sprouting. RNA-Seq analysis after the cells had undergone EndMT revealed large increases in chemokines and cytokines involved in regulating immune response. Gene set enrichment analysis of the data identified a number of pathways involved in myofibroblast biology suggesting that the endothelial cells had undergone a type II EMT. This type of EMT is involved in wound repair and is closely associated with inflammation implicating ELTD1 in these processes.

Expression of alpha-smooth muscle actin, TGF-β1 and TGF-β type II receptor during connective tissue contraction

1997 ◽  
Vol 33 (8) ◽  
pp. 622-627 ◽  
Author(s):  
M. Reza Ghassemifar ◽  
Roy W. Tarnuzzer ◽  
Nasser Chegini ◽  
Erkki Tarpila ◽  
Gregory S. Schultz ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Connective Tissue ◽  
Smooth Muscle Actin ◽  
Type Ii ◽  
Muscle Actin ◽  
Alpha Smooth Muscle Actin ◽  
Tissue Contraction ◽  
Tgf Β1
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