scholarly journals The specific NH2-terminal sequence Ac-EEED of alpha-smooth muscle actin plays a role in polymerization in vitro and in vivo.

1995 ◽  
Vol 130 (4) ◽  
pp. 887-895 ◽  
Author(s):  
C Chaponnier ◽  
M Goethals ◽  
P A Janmey ◽  
F Gabbiani ◽  
G Gabbiani ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Actin Polymerization ◽  
Smooth Muscle Actin ◽  
Muscle Actin ◽  
Alpha Smooth Muscle Actin ◽  
Fab Fragment ◽  
Acetyl Group ◽  
Antibody Complex

The blocking effect of the NH2-terminal decapeptide of alpha-smooth muscle (SM) actin AcEEED-STALVC on the binding of the specific monoclonal antibody anti-alpha SM-1 (Skalli, O., P. Ropraz, A. Trzeviak, G. Benzonana, D. Gillessen, and G. Gabbiani. 1986. J. Cell Biol. 103:2787-2796) was compared with that of synthetic peptides modified by changing the acetyl group or by substituting an amino acid in positions 1 to 5. Using immunofluorescence and immunoblotting techniques, anti-alpha SM-1 binding was abolished by the native peptide and by peptides with a substitution in position 5, indicating that AcEEED is the epitope for anti-alpha SM-1. Incubation of anti-alpha SM-1 (or of its Fab fragment) with arterial SM actin increased polymerization in physiological salt conditions; the antibody binding did not hinder the incorporation of the actin antibody complex into the filaments. This action was not exerted on skeletal muscle actin. After microinjection of the alpha-SM actin NH2-terminal decapeptide or of the epitopic peptide into cultured aortic smooth muscle cells, double immunofluorescence for alpha-SM actin and total actin showed a selective disappearance of alpha-SM actin staining, detectable at approximately 30 min. When a control peptide (e.g. alpha-skeletal [SK] actin NH2-terminal peptide) was microinjected, this was not seen. This effect is compatible with the possibility that the epitopic peptide traps a protein involved in alpha-SM actin polymerization during the dynamic filament turnover in stress fibers. Whatever the mechanism, this is the first evidence that the NH2 terminus of an actin isoform plays a role in the regulation of polymerization in vitro and in vivo.

Alpha-smooth muscle actin in pathological human disc nucleus pulposus cells in vivo and in vitro

2004 ◽  
Vol 12 (4) ◽  
pp. 430-438 ◽  
Author(s):  
Dawn Hastreiter ◽  
Jeannie Chao ◽  
QI Wang ◽  
Richard M. Ozuna ◽  
Myron Spector
Keyword(s):  
Smooth Muscle ◽  
Nucleus Pulposus ◽  
Smooth Muscle Actin ◽  
Muscle Actin ◽  
Nucleus Pulposus Cells ◽  
Alpha Smooth Muscle Actin

Alpha-smooth muscle actin expression by fibroblasts is not a marker of hypertrophic scars in vitro

1998 ◽  
Vol 16 ◽  
pp. S129
Author(s):  
Gianni Gerlini ◽  
Francesca Prignano ◽  
Nicola Pimpinelli ◽  
Lorenzo Borgognoni ◽  
Umberto Maria Reali ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Smooth Muscle Actin ◽  
Muscle Actin ◽  
Hypertrophic Scars ◽  
Alpha Smooth Muscle Actin ◽  
Actin Expression

scholarly journals Combination of 13-Cis Retinoic Acid and Lovastatin: Marked Antitumor Potential In Vivo in a Pheochromocytoma Allograft Model in Female Athymic Nude Mice

Endocrinology ◽  
2014 ◽  
Vol 155 (7) ◽  
pp. 2377-2390 ◽  
Author(s):  
Svenja Nölting ◽  
Alessio Giubellino ◽  
Yasin Tayem ◽  
Karen Young ◽  
Michael Lauseker ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Retinoic Acid ◽  
Smooth Muscle Actin ◽  
Treated Group ◽  
Muscle Actin ◽  
Tumor Mass ◽  
Viable Tumor ◽  
Over Time

Currently, there are no reliably effective therapeutic options for metastatic pheochromocytoma (PCC) and paraganglioma. Moreover, there are no therapies that may prevent the onset or progression of tumors in patients with succinate dehydrogenase type B mutations, which are associated with very aggressive tumors. Therefore, we tested the approved and well-tolerated drugs lovastatin and 13-cis-retinoic acid (13cRA) in vitro in an aggressive PCC mouse cell line, mouse tumor tissue-derived (MTT) cells, and in vivo in a PCC allograft nude mouse model, in therapeutically relevant doses. Treatment was started 24 hours before sc tumor cell injection and continued for 30 more days. Tumor sizes were measured from outside by caliper and sizes of viable tumor mass by bioluminescence imaging. Lovastatin showed antiproliferative effects in vitro and led to significantly smaller tumor sizes in vivo compared with vehicle treatment. 13cRA promoted tumor cell growth in vitro and led to significantly larger viable tumor mass and significantly faster increase of viable tumor mass in vivo over time compared with vehicle, lovastatin, and combination treatment. However, when combined with lovastatin, 13cRA enhanced the antiproliferative effect of lovastatin in vivo. The combination-treated mice showed slowest tumor growth of all groups with significantly slower tumor growth compared with the vehicle-treated mice and significantly smaller tumor sizes. Moreover, the combination-treated group displayed the smallest size of viable tumor mass and the slowest increase in viable tumor mass over time of all groups, with a significant difference compared with the vehicle- and 13cRA-treated group. The combination-treated tumors showed highest extent of necrosis, lowest median microvessel density and highest expression of α-smooth muscle actin. The combination of high microvessel density and low α-smooth muscle actin is a predictor of poor prognosis in other tumor entities. Therefore, this drug combination may be a well-tolerated novel therapeutic or preventive option for malignant PCC.

? Isoform of smooth muscle actin is expressed in astrocytes in vitro and in vivo

1991 ◽  
Vol 28 (4) ◽  
pp. 601-606 ◽  
Author(s):  
E. Lecain ◽  
F. Alliot ◽  
M. C. Laine ◽  
B. Calas ◽  
B. Pessac
Keyword(s):  
Smooth Muscle ◽  
Smooth Muscle Actin ◽  
Muscle Actin

scholarly journals Expression of alpha-smooth muscle actin in murine bone marrow stromal cells

Blood ◽  
1991 ◽  
Vol 78 (2) ◽  
pp. 304-309 ◽  
Author(s):  
A Peled ◽  
D Zipori ◽  
O Abramsky ◽  
H Ovadia ◽  
E Shezen
Keyword(s):  
Bone Marrow ◽  
Smooth Muscle ◽  
Cell Lines ◽  
Smooth Muscle Actin ◽  
Muscle Actin ◽  
Alpha Smooth Muscle Actin ◽  
Murine Bone Marrow ◽  
Cellular Origin ◽  
Hematopoietic Activity

Human fibrotic bone marrow (BM) stroma has been shown to contain alpha- smooth muscle actin (alpha-SMA)-positive cells. These closely resemble myofibroblasts that were described in other fibrotic tissues. We studied the expression of alpha-SMA in a series of murine BM-derived stromal cell lines to investigate the cellular origin and functional significance of myofibroblast-like cells in hematopoietic tissues. Although these cell lines differed in their biologic properties, most of them expressed alpha-SMA under certain conditions. Cells expressing alpha-SMA constituted a minor population in post-confluent, growth- arrested cultures. However, the incidence of cells expressing alpha-SMA increased significantly when cultures were transferred to nonconfluent conditions. A similar increase in alpha-SMA-positive cells occurred after a strip of cells was scraped away from the confluent cell layer; the cells of the affected area acquired alpha-SMA-positive contractile phenotype. The relationship between alpha-SMA expression and hematopoietic activity was studied using a cloned cell line of BM origin (14F1.1). The ability of these endothelial-adipocyte cells to support hematopoiesis in vitro was maximal under confluent conditions, whereas their expression of alpha-SMA under such conditions was residual. Moreover, in long-term BM cultures supported by confluent 14F1.1 cells, stromal areas associated with proliferating hematopoietic precursors, known as “cobblestone areas,” were devoid of alpha-SMA- positive cells. These observations suggest that the expression of alpha- SMA is reversible and inversely related to hematopoietic activity.

scholarly journals The NH2-terminal peptide of α–smooth muscle actin inhibits force generation by the myofibroblast in vitro and in vivo

2002 ◽  
Vol 157 (4) ◽  
pp. 657-663 ◽  
Author(s):  
Boris Hinz ◽  
Giulio Gabbiani ◽  
Christine Chaponnier
Keyword(s):  
Smooth Muscle ◽  
Granulation Tissue ◽  
Contractile Activity ◽  
Smooth Muscle Actin ◽  
Topical Administration ◽  
Force Generation ◽  
Muscle Actin ◽  
Actin Isoforms

Myofibroblasts are specialized fibroblasts responsible for granulation tissue contraction and the soft tissue retractions occurring during fibrocontractive diseases. The marker of fibroblast-myofibroblast modulation is the neo expression of α–smooth muscle actin (α-SMA), the actin isoform typical of vascular smooth muscle cells that has been suggested to play an important role in myofibroblast force generation. Actin isoforms differ slightly in their NH2-terminal sequences; these conserved differences suggest different functions. When the NH2-terminal sequence of α-SMA Ac-EEED is delivered to cultured myofibroblast in the form of a fusion peptide (FP) with a cell penetrating sequence, it inhibits their contractile activity; moreover, upon topical administration in vivo it inhibits the contraction of rat wound granulation tissue. The NH2-terminal peptide of α–skeletal actin has no effect on myofibroblasts, whereas the NH2-terminal peptide of β–cytoplasmic actin abolishes the immunofluorescence staining for this isoform without influencing α-SMA distribution and cell contraction. The FPs represent a new tool to better understand the specific functions of actin isoforms. Our findings support the crucial role of α-SMA in wound contraction. The α-SMA–FP will be useful for the understanding of the mechanisms of connective tissue remodeling; moreover, it furnishes the basis for a cytoskeleton-dependent preventive and/or therapeutic strategy for fibrocontractive pathological situations.

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