Effects of hydrogen-sulfide donor, morpholin- 4-ium 4-methoxyphenyl (morpholino) phosphinodithioate, on immune cells involved in experimental autoimmune encephalomyelitis pathogenesis

Multipla skleroza (MS) je hronična, inflamacijska, demijelinizujuća, neurodegenerativna bolest centralnog nervnog sistema. U cilju boljeg razumevanja faktora koji utiču na patogenezu MS-e, kao i definisanja novih potencijalnih terapeutika, u ovoj doktorskoj disertaciji je ispitivan efekat sporooslobađajućeg donora vodonik-sulfida, GYY4137, na imunske ćelije uključene u patogenezu eksperimentalnog autoimunskog encefalomijelitisa (EAE), najčešće korišćenog životinjskog modela MS-e. GYY4137 je ostvario jasan antiiflamacijski efekat na BV2 ćelije (ćelijska linija mikroglije), dok je njegov efekat na dendritske ćelije (DĆ) diferentovane iz ćelija kostne srži C57BL/6 miševa bio ograničen. Takođe, GYY4137 nije uticao na procentualnu zastupljenost Th1 i Th17 limfocita, glavnih patogenih populacija T limfocita u patogenezi EAE-a, unutar populacije ćelija poplitealnih limfnih čvorova (PLČ) imunizovanih C57BL/6 miševa i/ili DA pacova, ali je doveo do smanjenja zastupljenosti Th17 limfocita unutar populacije imunskih ćelija izolovanih iz kičmene moždine imunizovanih pacova. S druge strane, ovo jedinjenje je dovelo do smanjenja zastupljenosti regulatornih T limfocita (Treg) unutar populacije ćelija PLČ, ali nije uticalo na njihovu zastupljenost unutar populacije imunskih ćelija izolovanih iz kičmene moždine. Mehanizam kojim je GYY4137 ostvario efekat na zastupljenost Treg unutar populacije ćelija PLČ je obuhvatao smanjenje ekspresije transkripcionog faktora FoxP3, koje je najverovatnije bilo posredovano stimulacijom njegove proteazomalne degradacije. Pored toga, ovo jedinjenje je dovelo do povećanja produkcije reaktivnih vrsta kiseonika u BV2 ćelijama i CD4+ T limfocitima izolovanim iz PLČ imunizovanih miševa. Rezultati ove doktorske disertacije ukazuju na to da GYY4137 ostvaruje imunomodulacijski efekat na imunske ćelije uključene u patogenezu EAE-a, pri čemu priroda i intenzitet ovog efekta zavise od ćelijske populacije na koju se dejstvo ostvaruje, kao i od miljea iz kojeg ćelije potiču. Takođe, ovi rezultati ukazuju na to da GYY4137 poseduje značajan antiencefalitogeni potencijal.Multiple sclerosis (MS) is a chronic, inflammatory, demyelinating, neurodegenerative disease of the central nervous system. The aim of this doctoral dissertation has been to improve knowledge about factors that influence MS pathogenesis and to define new potential MS therapeutics by examination of the effects of slow-releasing hydrogen-sulfide donor, GYY4137, on immune cells involved in the pathogenesis of experimental autoimmune encephalomyelitis (EAE), commonly used MS animal model. Immunomodulatory effect of in vitro treatment with GYY4137 was investigated on BV2 cells (microglial cell line) and dendritic cells (DC) differentiated from bone marrow precursors of C57BL/6 mice. GYY4137 exerted potent anti-inflammatory effects on BV2 cells, while its effects on DC were limited. Further, GYY4137 effect on the percentage of different T cell subpopulations among cells isolated from popliteal lymph nodes (PLN) or spinal cords of immunized C57BL/6 mice and/or DA rats was evaluated. The results showed that, despite having no effect on the percentage of two major pathogenic T helper (Th) cell populations in EAE (Th1 and Th17 cells) among cells from PLN, GYY4137 reduced the percentage of Th17 among immune cells isolated from spinal cords of immunized rats. In contrast to the effect on the percentage of Th17 cells, GYY4137 reduced the percentage of regulatory T cells (Treg) among PLN cells, but not among immune cells obtained from spinal cords of immunized rats. GYY4137 accomplished its effect on the Treg percentage by reducing the relative protein expression of FoxP3, which was probably mediated by stimulation of its proteasomal degradation. Furthermore, GYY4137 potentiated reactive oxygen species generation in BV2 cells and CD4+ T cells isolated from PLN of immunized mice. The results of this doctoral thesis indicate that GYY4137 exerts immunomodulatory effects on immune cells involved in EAE pathogenesis, while the nature and intensity of these effects depend on the cell type and the milieu of cellular origin. Also, these results suggest that GYY4137 has a significant anti-encephalitogenic potential