scholarly journals Role of stromal cells and macrophages in fibronectin biosynthesis and matrix assembly in human long-term marrow cultures

Blood ◽  
1993 ◽  
Vol 82 (5) ◽  
pp. 1480-1492 ◽  
Author(s):  
H Lerat ◽  
JC Lissitzky ◽  
JW Singer ◽  
A Keating ◽  
P Herve ◽  
...  
Keyword(s):  
Extracellular Matrix ◽  
Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Stromal Cells ◽  
Muscle Cells ◽  
Cell Populations ◽  
Matrix Assembly ◽  
Marrow Cultures

Abstract Fibronectin is a major component of the extracellular matrix of adherent layers of human long-term marrow cultures where it may stabilize the extracellular matrix network and provide adhesion sites for primitive hemopoietic cells. This study was devised to analyze the role of adherent cell populations in fibronectin synthesis, matrix assembly, and degradation. In cultures performed under the conditions described by Gartner and Kaplan, immunoprecipitation after metabolic labeling showed that adherent cells synthesized a fibronectin variant comprising the EDa domain and lacking the EDb one. Vascular smooth muscle-like stromal cells were the cell subset responsible for this synthesis. Once synthesized by stromal cells, EDa+fibronectin was secreted into the supernatant and incorporated into the extracellular matrix. The cumulation in the extracellular matrix was predominant by weeks 5 and 6 of culture, when a decrease in the stromal cell intracytoplasmic content of fibronectin was observed. Stromal cells from a transformed cell line, L2Ori-, were also able to synthesize the EDa+fibronectin variant, although for these cells the assembly into the extracellular matrix was partly impaired. Besides stromal cells, other cell types participated in fibronectin synthesis: early-adhering granulomonocytic cells and macrophages appearing later in culture were able to synthesize an EDa-, EDb- fibronectin variant, clearly distinct from the EDa+ variant produced by stromal cells. Studies on cultures in which macrophage growth was stimulated at the expense of stromal cells by adding granulocyte-macrophage colony-stimulating factor (50 ng/mL) to the culture medium showed a striking decrease in amounts of fibronectin measured in the adherent layer. This decrease was caused by a lack of incorporation of fibronectin in the extracellular matrix, disclosing a major difference between stromal cells and macrophages in terms of matrix assembly. This study confirms the similarity between stromal cells and vascular smooth muscle cells, because in vivo subendothelial intimal aortic smooth muscle cells and cultured smooth muscle cells from the aortic media express the EDa+, EDb- fibronectin variant. Furthermore, our results suggest that the level of fibronectin in adherent layers is regulated by stromal cells and macrophages. The balance between these two cell populations may therefore be crucial for the local control of hemopoiesis by regulating the extracellular fibronectin available for the adhesion of hematopoietic cells. Our data indicate that it may be essential to study the adhesion of stem cells to EDa+, EDb- fibronectin instead of EDa-, EDb- soluble fibronectin, as found in human plasma.

scholarly journals Role of stromal cells and macrophages in fibronectin biosynthesis and matrix assembly in human long-term marrow cultures

Blood ◽  
1993 ◽  
Vol 82 (5) ◽  
pp. 1480-1492 ◽  
Author(s):  
H Lerat ◽  
JC Lissitzky ◽  
JW Singer ◽  
A Keating ◽  
P Herve ◽  
...  
Keyword(s):  
Extracellular Matrix ◽  
Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Stromal Cells ◽  
Muscle Cells ◽  
Cell Populations ◽  
Matrix Assembly ◽  
Marrow Cultures

Fibronectin is a major component of the extracellular matrix of adherent layers of human long-term marrow cultures where it may stabilize the extracellular matrix network and provide adhesion sites for primitive hemopoietic cells. This study was devised to analyze the role of adherent cell populations in fibronectin synthesis, matrix assembly, and degradation. In cultures performed under the conditions described by Gartner and Kaplan, immunoprecipitation after metabolic labeling showed that adherent cells synthesized a fibronectin variant comprising the EDa domain and lacking the EDb one. Vascular smooth muscle-like stromal cells were the cell subset responsible for this synthesis. Once synthesized by stromal cells, EDa+fibronectin was secreted into the supernatant and incorporated into the extracellular matrix. The cumulation in the extracellular matrix was predominant by weeks 5 and 6 of culture, when a decrease in the stromal cell intracytoplasmic content of fibronectin was observed. Stromal cells from a transformed cell line, L2Ori-, were also able to synthesize the EDa+fibronectin variant, although for these cells the assembly into the extracellular matrix was partly impaired. Besides stromal cells, other cell types participated in fibronectin synthesis: early-adhering granulomonocytic cells and macrophages appearing later in culture were able to synthesize an EDa-, EDb- fibronectin variant, clearly distinct from the EDa+ variant produced by stromal cells. Studies on cultures in which macrophage growth was stimulated at the expense of stromal cells by adding granulocyte-macrophage colony-stimulating factor (50 ng/mL) to the culture medium showed a striking decrease in amounts of fibronectin measured in the adherent layer. This decrease was caused by a lack of incorporation of fibronectin in the extracellular matrix, disclosing a major difference between stromal cells and macrophages in terms of matrix assembly. This study confirms the similarity between stromal cells and vascular smooth muscle cells, because in vivo subendothelial intimal aortic smooth muscle cells and cultured smooth muscle cells from the aortic media express the EDa+, EDb- fibronectin variant. Furthermore, our results suggest that the level of fibronectin in adherent layers is regulated by stromal cells and macrophages. The balance between these two cell populations may therefore be crucial for the local control of hemopoiesis by regulating the extracellular fibronectin available for the adhesion of hematopoietic cells. Our data indicate that it may be essential to study the adhesion of stem cells to EDa+, EDb- fibronectin instead of EDa-, EDb- soluble fibronectin, as found in human plasma.

scholarly journals Stromal cells from human long-term marrow cultures are mesenchymal cells that differentiate following a vascular smooth muscle differentiation pathway

Blood ◽  
1993 ◽  
Vol 82 (1) ◽  
pp. 66-76 ◽  
Author(s):  
MC Galmiche ◽  
VE Koteliansky ◽  
J Briere ◽  
P Herve ◽  
P Charbord
Keyword(s):  
Smooth Muscle ◽  
Vascular Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Stromal Cells ◽  
Muscle Cells ◽  
Mesenchymal Cells ◽  
Myoid Cells ◽  
Marrow Cultures

In human long-term marrow cultures connective tissue-forming stromal cells are an essential cellular component of the adherent layer where granulomonocytic progenitors are generated from week 2 onward. We have previously found that most stromal cells in confluent cultures were stained by monoclonal antibodies directed against smooth muscle- specific actin isoforms. The present study was carried out to evaluate the time course of alpha-SM-positive stromal cells and to search for other cytoskeletal proteins specific for smooth muscle cells. It was found that the expression of alpha-SM in stromal cells was time dependent. Most of the adherent spindle-shaped, vimentin-positive stromal cells observed during the first 2 weeks of culture were alpha- SM negative. On the contrary, from week 3 to week 7, most interdigitated stromal cells contained stress fibers whose backbone was made of alpha-SM-positive microfilaments. In addition, in confluent cultures, other proteins specific for smooth muscle were detected: metavinculin, h-caldesmon, smooth muscle myosin heavy chains, and calponin. This study confirms the similarity between stromal cells and smooth muscle cells. Moreover, our results reveal that cells in vivo with the phenotype closest to that of stromal cells are immature fetal smooth muscle cells and subendothelial intimal smooth muscle cells; a cell subset with limited development following birth but extensively recruited in atherosclerotic lesions. Stromal cells very probably derive from mesenchymal cells that differentiate along this distinctive vascular smooth muscle cell pathway. In humans, this differentiation seems crucial for the maintenance of granulomonopoiesis. These in vitro studies were completed by examination of trephine bone marrow biopsies from adults without hematologic abnormalities. These studies revealed the presence of alpha-SM-positive cells at diverse locations: vascular smooth muscle cells in the media of arteries and arterioles, pericytes lining capillaries, myoid cells lining sinuses at the abluminal side of endothelial cells or found within the hematopoietic logettes, and endosteal cells lining bone trabeculae. More or less mature cells of the granulocytic series were in intimate contact with the thin cytoplasmic extensions of myoid cells. Myoid cells may be the in vivo counterpart of stromal cells with the above-described vascular smooth muscle phenotype.

scholarly journals Different DNA methylome, transcriptome and histological features in uterine fibroids with and without MED12 mutations

2021 ◽  
Author(s):  
Ryo Maekawa ◽  
Shun Sato ◽  
Tetsuro Tamehisa ◽  
Takahiro Sakai ◽  
Takuya Kajimura ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Extracellular Matrix ◽  
Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Blood Vessels ◽  
Uterine Fibroids ◽  
Muscle Cells ◽  
Histological Features ◽  
Dna Methylome

Abstract Background: Somatic mutations in Mediator complex subunit 12 (MED12m) have been reported as a biomarker of uterine fibroids (UFs). However, the role of MED12m is still unclear in the pathogenesis of UFs. Therefore, we investigated the differences in DNA methylome, transcriptome, and histological features between MED12m-positive and -negative UFs. Methods: DNA methylomes and transcriptomes were obtained from MED12m-positive and -negative UFs and myometrium, and hierarchically clustered. Differentially expressed genes in comparison with the myometrium and co-expressed genes detected by weighted gene co-expression network analysis were subjected to gene ontology enrichment analyses. The amounts of collagen fibers and the number of blood vessels and smooth muscle cells were histologically evaluated. Results: Hierarchical clustering based on DNA methylation clearly separated the myometrium, MED12m-positive, and MED12m-negative UFs. MED12m-positive UFs had the increased activities of extracellular matrix formation, whereas MED12m-negative UFs had the increased angiogenic activities and smooth muscle cell proliferation. Conclusion: The MED12m-positive and -negative UFs had different DNA methylation, gene expression, and histological features. The MED12m-positive UFs form the tumor with a rich extracellular matrix and poor blood vessels and smooth muscle cells compared to the MED12m-negative UFs, suggesting MED12 mutations affect the tissue composition of UFs.

scholarly journals Actin cytoskeletal dynamics in smooth muscle: a new paradigm for the regulation of smooth muscle contraction

2008 ◽  
Vol 295 (3) ◽  
pp. C576-C587 ◽  
Author(s):  
Susan J. Gunst ◽  
Wenwu Zhang
Keyword(s):  
Extracellular Matrix ◽  
Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Actin Polymerization ◽  
Muscle Cells ◽  
Smooth Muscle Contraction ◽  
Mechanical Tension ◽  
Muscle Tissues ◽  
Cytoskeletal Dynamics

A growing body of data supports a view of the actin cytoskeleton of smooth muscle cells as a dynamic structure that plays an integral role in regulating the development of mechanical tension and the material properties of smooth muscle tissues. The increase in the proportion of filamentous actin that occurs in response to the stimulation of smooth muscle cells and the essential role of stimulus-induced actin polymerization and cytoskeletal dynamics in the generation of mechanical tension has been convincingly documented in many smooth muscle tissues and cells using a wide variety of experimental approaches. Most of the evidence suggests that the functional role of actin polymerization during contraction is distinct and separately regulated from the actomyosin cross-bridge cycling process. The molecular basis for the regulation of actin polymerization and its physiological roles may vary in diverse types of smooth muscle cells and tissues. However, current evidence supports a model for smooth muscle contraction in which contractile stimulation initiates the assembly of cytoskeletal/extracellular matrix adhesion complex proteins at the membrane, and proteins within this complex orchestrate the polymerization and organization of a submembranous network of actin filaments. This cytoskeletal network may serve to strengthen the membrane for the transmission of force generated by the contractile apparatus to the extracellular matrix, and to enable the adaptation of smooth muscle cells to mechanical stresses. Better understanding of the physiological function of these dynamic cytoskeletal processes in smooth muscle may provide important insights into the physiological regulation of smooth muscle tissues.

scholarly journals Dynamic Crosstalk between Vascular Smooth Muscle Cells and the Aged Extracellular Matrix

2021 ◽  
Vol 22 (18) ◽  
pp. 10175
Author(s):  
Joao Carlos Ribeiro-Silva ◽  
Patricia Nolasco ◽  
Jose Eduardo Krieger ◽  
Ayumi Aurea Miyakawa
Keyword(s):  
Extracellular Matrix ◽  
Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Muscle Cells ◽  
Elastic Fibers ◽  
Signaling Mechanisms ◽  
Arterial Aging ◽  
Underlying Mechanisms ◽  
Cell Phenotypes

Vascular aging is accompanied by the fragmentation of elastic fibers and collagen deposition, leading to reduced distensibility and increased vascular stiffness. A rigid artery facilitates elastin to degradation by MMPs, exposing vascular cells to greater mechanical stress and triggering signaling mechanisms that only exacerbate aging, creating a self-sustaining inflammatory environment that also promotes vascular calcification. In this review, we highlight the role of crosstalk between smooth muscle cells and the vascular extracellular matrix (ECM) and how aging promotes smooth muscle cell phenotypes that ultimately lead to mechanical impairment of aging arteries. Understanding the underlying mechanisms and the role of associated changes in ECM during aging may contribute to new approaches to prevent or delay arterial aging and the onset of cardiovascular diseases.

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