scholarly journals Extracellular Matrix Molecules and their Receptors: An Overview with Special Emphasis on Periodontal Tissues

1991 ◽  
Vol 2 (3) ◽  
pp. 323-354 ◽  
Author(s):  
Veli-Jukka Uitto ◽  
Hannu Larjava

Knowledge of extracellular matrix molecules and their cell receptors has increased exponentially during the last 2 decades. It is now known that the structure and function of each tissue is based on specific combinations of matrix molecules. The major constituents of the extracellular matrix are collagens, proteoglycans, and adhesive glycoproteins. The rapid development of biochemical, molecular biological, and immunological research has revealed a lot of interesting details pertaining to these molecules. Several new collagen types have been discovered. In addition to being responsible for the strength and form of tissues, each collagen type has specific sequences providing them with special features such as flexibility and the ability to interact with other matrix molecules and cells. Proteoglycans are another large group of matrix molecules with a variety of functions. Proteoglycans play an important role in tissue resilience and filtering. Some proteoglycans have a capacity to specifically bind other matrix molecules and growth factors, while others act as matrix receptors on the cell surface. An important part of regulation of the cell behavior is played by adhesive glycoproteins belonging to the fibronectin and laminin families. Several isoforms of fibronectin and laminin that result from alternative RNA splicing serve specific functions such as controlling the attachment, migration, and synthetic activity of cells. A major group of cell receptors for cell-matrix and cell-cell interactions is termed integrins. The integrins are cell surface proteins composed of two polypeptides whose structure dictates the specificity of each receptor. The cytoplasmic domain of the integrins interacts with cytoskeletal elements within the cell, and thereby relays the information from the extracellular space into the protein synthesis machinery. The expression of the integrins is controlled by the extracellular matrix and growth factors, most notably TGFβ. During periodontal diseases several aspects of the cell-matrix interactions may be disturbed. Therefore, an understanding of the special features of the extracellular matrix and their receptors in periodontal tissues is a prerequisite for developing new approaches to the prevention and treatment of periodontal diseases.

2004 ◽  
Vol 32 (3) ◽  
pp. 416-420 ◽  
Author(s):  
R. Zaidel-Bar ◽  
M. Cohen ◽  
L. Addadi ◽  
B. Geiger

The adhesion of cells to the extracellular matrix is a dynamic process, mediated by a series of cell-surface and matrix-associated molecules that interact with each other in a spatially and temporally regulated manner. These interactions play a major role in tissue formation, cellular migration and the induction of adhesion-mediated transmembrane signals. In this paper, we show that the formation of matrix adhesions is a hierarchical process, consisting of several sequential molecular events. One of the earliest steps in surface recognition is mediated, in some cells, by a 1 μm-thick cell-surface hyaluronan coat, which precedes the establishment of stable, cytoskeleton-associated adhesions. The earliest forms of these integrin-mediated contacts are dot-shaped FXs (focal complexes), which are formed under the protrusive lamellipodium of migrating cells. These adhesions recruit, sequentially, different anchor proteins that are involved in binding the actin cytoskeleton to the membrane. Conspicuous in its absence from FXs is zyxin, which is recruited to these sites only on retraction of the leading edge and the transformation of the FXs into a focal adhesion. Continuing application of force to focal adhesions results in the formation of fibrillar adhesions and reorganization of the extracellular matrix. The formation of these adhesions depends on actomyosin contractility and matrix pliability.


2020 ◽  
Vol 9 (1) ◽  
pp. 784-788

Periodontitis is a chronic inflammatory disease of the vascularized supporting tissues of the teeth. Angiogenesis (neovascularization) is the budding of new capillaries and is thought to be an essential process in the development of chronic inflammatory diseases. Inflamed tissues (such as gingiva coincident in periodontal disease) have evidence of enhanced expression of inflammatory mediators, many of which can promote angiogenesis. Of the various cytokines and growth factors that are involved in angiogenesis, the most potent agent that acts specifically on vascular epithelium is Vascular Endothelial Growth Factor. Even though angiogenesis is a prominent feature of both inflammation and healing, information about its role in periodontal lesions is limited. Hence the aim of the present study was the immunohistochemical evaluation of the expression of VEGF in the gingival tissues of chronic and aggressive periodontitis patients compared to the healthy controls. The present study was carried out in a total of 45 subjects with age range of 18-55 years, reporting to the Department of Periodontology, Rajarajeswari Dental College and Hospital, Bangalore. Gingival tissue samples were collected from all the 45 subjects and categorized into three groups based on their clinical findings as follows: Group 1 (Healthy), Group II (Chronic Periodontitis), Group III (Aggressive Periodontitis). Following sample collection, immunohistochemical staining of tissues was carried out and evaluation was done to compare the grades of expression of VEGF in the three groups. The expression of VEGF in blood vessels was also quantitatively evaluated. The results were statistically analyzed using Kruskal Wallis ANOVA and Mann Whitney test. There was a statistically significant higher expression of VEGF in both chronic periodontitis and aggressive periodontitis group as compared to the control group. Aggressive periodontitis cases showed higher grades of expression of VEGF compared to the chronic periodontitis cases and healthy controls. However, the difference in expression of VEGF was not statistically significant between the two forms of periodontitis. The presence of VEGF in both chronic and aggressive periodontitis clearly indicates the potent role played by VEGF as an inflammatory agent in the initiation and progression of periodontal diseases. Thus, VEGF might be used as a potential vascular marker for the assessment of severity and inflammatory status in periodontal disease.


2002 ◽  
Vol 115 (2) ◽  
pp. 257-265
Author(s):  
Josephine Clare Adams

The extracellular matrix is vital for tissue organisation in multicellular organisms. Cells attach to the extracellular matrix at discrete points on the cell surface, termed cell-matrix contacts. In general molecular terms, these contacts are assembled from large multiprotein complexes. However, many forms of matrix contacts can be distinguished by microscopy or by biochemical criteria, and these fulfil a diverse range of roles associated with cell adhesion, guidance, migration, matrix assembly, differentiation and survival. Two major functional categories are the protrusive and contractile matrix contacts. I describe contexts for the formation of protrusive or contractile contacts and discuss recent information on the molecular processes by which these contacts are specified, coordinated and regulated at a cellular level.


2014 ◽  
Vol 27 (4) ◽  
pp. 209-212
Author(s):  
Iwona Kaznowska-Bystryk

Abstract Heparan sulfate (HS) is one of the most common glycosaminoglycan (GAG) in mammals. It is composed of relatively simple disaccharide subunits, which, by further modification, such as sulfation and epimerization, potentially offer huge diversity in biological function. GAG chains of different length, different patterns of sulfation, and other modifications, depending on location, generate unique forms. Due to polyanion charges, these compounds can interact with other molecules, such as proteins, cytokines, chemokines and growth factors, both on the cell surface and inside the extracellular matrix. These interactions serve protective and storage functions for the compounds, safeguarding them from proteolysis. In this way, HS is involved in numerous signaling pathways, and in growth and differentiation processes. Disrupted interactions between the HS and growth factors, cytokines or other proteins have been observed in various disorders, among these Alzheimer’s disease, epilepsy, atherosclerosis, diabetes, and cancer processes. Detailed knowledge of these relationships at the molecular level will allow researchers to understand the mechanisms underlying these disorders and enable the development of effective therapeutic strategies.


Author(s):  
Suellen M. Feitosa ◽  
Maria A. T. Bortolini ◽  
Gisela R. F. Salerno ◽  
Andreisa P. M. Bilhar ◽  
Silvia S. M. Ihara ◽  
...  

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