CURRENT VIEW CONCERNING MOLECULAR-GENETIC MECHANISMS OF THE INTER-CELLULAR INTERACTION IN THE PROCESS OF OSSEOUS REMODELING

Abstract

Bones are not inert structures inside the human body; they respond dynamically and with high plasticity to exo- and endogenous factors by changes of their content, structure, characteristics of solidity, etc. This process of skeletal changes known as bone remodeling provides structural integrity of the osseous system and promotes metabolic balance of calcium and phosphorus; remodeling causes resorption of the old or damaged bone followed by the formation of new osseous material. Bone morphogenetic proteins (BMP) constituting a group of morphogenetic signal growth factors (known as cytokines as well) first were described as molecules stimulating formation of the endochondrial osseous tissue. Osteoprotegerin (OPG) is a representative of the super-family of soluble factors to tumor necrosis factor-α (TNF-α) and belongs to secretory low molecular glycoproteins which trans-membrane receptors are located on the surface of osteoblasts, immune cells and precursors of osteoclasts. Transforming growth factor-β1 (TGFβ1) is a representative of cytokines protein in nature, released into the intercellular matrix by the osseous tissue cells and macrophages. It controls a life cycle of cells from the osteoid line, that is, their proliferation, cellular differentiation and functional activity. Sclerostin is produced by osteocytes, mineralized hypertrophic chondrocytes and cementocytes (dental cells) only. It belongs to the components of DAN glycoprotein family (differential screening-selected aberrant genes of neuroblastoma).