SYMPOSIUM: MULTIPLE SCLEROSIS. Chemokines and their receptors in experimental autoimmune inflammation in the CNS
Bartosz Bielecki, Izabela Jatczak, Andrzej Głąbiński
Chemokines are a family of small alkaline proteins with molecular weight of 6 to 14 kDa. Depending on physiological activities they can be divided into two groups, homeostatic (constitutive) and inflammatory. Homeostatic chemokines (e.g., CCL19, CCL21, CCL25, CCL27, CXCL12 and CXCL13) are usually constitutively expressed in the specific microenvironments of lymphoid organs and peripheral tissues. In contrast, inflammatory chemokines (e.g., CCL1, CCL2, CCL11, CCL17 and CCL22) are involved in development of inflammation. Their expression is induced by another inflammatory cytokines such as IL-1β or TNF. Chemokines act on various types of target cells through rhodopsin like G protein-coupled receptors. The main function of chemokines is induction of directed chemotaxis of different types of target cells. Moreover, they regulate inflammatory process and differentiation of immunological cells. Physiologically, chemokines constitutively expressed in the central nervous system (CNS) can initiate multipotential progenitor cells and neurons migration during the development of the brain as well as they can act as a trophic factors for neurons. The close correlation between the expression of chemokines and the influx of inflammatory cells to the CNS during an animal model of multiple sclerosis (MS) – experimental autoimmune encephalomyelitis (EAE) was observed. The mRNA expression of chemokines CCL2, CCL3, CCL4, CCL5, CCL7 and CXCL10 as well as chemokine receptors CCR2, CCR5, CCR8, CXCR2, CXCR3, CXCR4 andCX3CR1 in the CNS of animals with EAE was increased. These data suggest that chemokines and their receptors may be involved in the pathogenesis of autoimmune neuroinflammation, including MS.