We study the different structures and functions of cells with special focus on stem cells and associated regulatory systems responsible for gene expression. In this context, we are interested in exploring the basic information regarding the structure and organization of the organelles in cells, their physiological properties, metabolic processes, signaling pathways, life cycle, and interactions with different biomaterials and nanoparticles in biological environments. The main components of the molecular composition of cells including proteins and lipids which are either free flowing or membrane bound along with different internal compartments has shown a verity of responses in different systems. Therefore, understanding regarding the components of cells and their mechanism of action are fundamental to all biological sciences essential for research in all medical related projects. Our research in this subject is closely related to genetics, biochemistry, molecular biology, immunology, and developmental biology.
The reaction patterns of chondrocytes in osteoarthritis are categories into proliferation and apoptosis, changes in synthetic activity and degradation, phenotypic modulation of the articular chondrocytes, and formation of osteophytes. This sort of joint disorders have been traditionally defined as a prototypical non-inflammatory arthropathy, but today we believe that there are compelling evidences suggesting that they have an inflammatory component. There is a direct association between joint inflammation and the progression of osteoarthritis. Pro-inflammatory cytokines, reactive oxygen species (ROS), nitric oxide, matrix degrading enzymes and biomechanical stress are major factors responsible for the progression of osteoarthritis in synovial joints. We are actively working on inflammatory mediators and their contribution to the progression of osteoarthritis according to a molecular cell biology base. The group has offered some guidelines, practices, and prospects. In addition, the group seeks new innovations in methodologies and instrumentation for the non-invasive detection of inflammation in osteoarthritis by modern imaging techniques. We are working on recognizing early inflammatory events and targeting these alterations to ameliorate the major symptoms such as inflammation and pain in osteoarthritis patients.
- Mathematical modeling and computational representations of cellular processes can provide us with valuable informations for valid anticipations of cellular behaviors in specific applications. We are developing detailed theoretical models that combine the conventional viscoelastic continuum description of cell motion with a dynamic active stress. Our most recent model describes the ameboid cells movement comprising of protrusion and adhesion of the front edge followed by detachment and movement of the tail. Unlike the previous viscoelastic descriptions in which the cell movement is steady, our new model describes the “walking” of the cell in response to specific active stress components acting separately on the front and rear of the cell. In this locomotive model first the tail of the cell is attached to the substrate and active stress is applied to the front of the cell. Consequently, the stress in the tail increases. When the stress in the tail exceeds a critical value, namely critical stress, the conditions are updated so that the front is fixed and the tail of the cell is detached from the substrate and moves towards the front. Consequently, the stress in the tail decreases. When the stress goes to zero, the starting conditions become active and the process continues. At start the cell is stretched and its length is increased as the front of cell migrates more than the rear. However, after several steps the front and rear move equally and the cell length stays constant during the movement. We are also working on modeling regulatory systems responsible for gene expression structured by networks of interactions between DNA, RNA, proteins, and small molecules.
- Due to the delayed and weak tissue-implant integration, there have been several attempts to enhance these interactions for rapid integration. To understand the logic behind the behavior of cells on the surface of implants, we first develop different biocompatible and/or bioactive thin film and coating systems on medical implants, and then examine the interactions with stem cells. In one of our recent studies, we have examined the interactions of human bone marrow-derived stromal stem cells with uncoated- and coated-poorly crystalline apatite titanium dental/orthopedic implants. After configuration and chemical composition assessment of the coatings and their deposition progress in different experimental conditions, the cells are cultured on the substrates and cell attachment and proliferation are monitored and evaluated. Surprisingly, although the uncoated and coated implants indicate acceptable cell attachment, the differences in proliferation and morphology of the cells spread over the coated samples are significant. Our primary results indicate that such meaningful cell migration is directly associated to the osteoconduction, confirming our hypothesis of enhancement in bone formation on the surface of poorly crystalline apatite coated titanium implants. These indicate that our modified samples are ready for ongoing osteogenic studies in bone or dental defects in animal models.