Interakcija mezenhimskih matičnih ćelija iz periapeksnih lezija i fagocita

In this PhD thesis the interactions of mesenchymal stem cells from periapical lesions (PL-MSC) with inflammatory cells and phagocytes (granulocytes and macrophages) were examined in vitro, trough phenotypic changes, cytokines production, differentiation, apoptosis and NET-osis. The effects were investigated in direct cell-to-cell contacts and in transwell system. In order to imitate the most reliable settings like in vivo conditions, co-cultures were treated with pro-inflammatory stimuli. It has been shown that PL-MSC possess fibroblast-like morphology, have great capacity for self renewing, form colonies with exponential growth rate, differentiate into osteoblasts, chondrocytes and adypocytes and express markers typical for other dental MSC. Based on histological analysis and literature data about other MSC, it could be postulated that PL-MSC resides within the subpopulation of pericytes. LPS, Poly I:C, Pam3CSK4 and cytokine cocktail (IL-1β, TNF-α, IL-6) with PGE2 up-regulate the expression of CD73 and IDO-1 molecules, but differently modulate cytokine production by PL-MSC. PL-MSC up-regulate the production of immunoregulatory cytokines by total inflammatory cells (IC) from PL. PL-MSC isolated from clinically different lesions, down-modulate the production of pro-inflammatory cytokines, but up-regulate the production of immunoregulatory cytokines by mononuclear cells in PL. PL-MSC (pericytes) form close contacts with granulocytes and macrophages in situ, which could trigger their cross-talk interactions. Namely, PL-MSC down-modulate the production of TNF-α by native and activated (LPS, fMLP) granulocytes and inhibit their apoptosis, where IL-6 has a dominant role. On the other side, granulocytes stimulate the production of IL-6 by PL-MSC. NET differently modulated the production of cytokines panel by PL-MSC in culture, but PL-MSC do not affect NET-osis. PL-MSC pollarized spontaneously differentiated macrophages (sMØ) towards M1, and M-CSF (mMØ)- or GM-CSF (gmMØ)- induced macrophages towards M2 phenotype. Generally, despite anti-inflammatory and immunosuppressive potential, PL-MSC promote certain inflammatory reactions in PL, via cross-talk with phagocytes, suggesting their functional plasticity