Uloga mikrobiote i limfnog tkiva creva u otpornosti pacova soja Albino Oksford na indukciju eksperimentalnog autoimunskog encefalomijelitisa

Abstract

Multipla skleroza je hronična, inflamacijska, neurodegenerativna, demijelinizirajuća bolest centralnog nervnog sistema (CNS). Etiologija multiple skleroze još uvek nije poznata, ali je sve više podataka koji pokazuju ulogu crevne mikrobiote u patogenezi bolesti. Više podataka o značaju crevne mikrobiote u autoimunosti CNS dobijeno je istraživanjima na eksperimentalnom autoimunskom encefalomijelitisu (EAE), životinjskom modelu multiple skleroze. U EAE-u se autoimunski odgovor protiv CNS-a pokreće u limfnim čvorovima koji dreniraju mesto imunizacije, gde se CD4+ T ćelije specifične za antigene CNS-a aktiviraju i diferenciraju u Th (engl. T helper) 1 ćelije koje produkuju IFN-γ i Th17 ćelije koje produkuju IL-17. Kada dospeju u CNS ove Th ćelije bivaju reaktivirane od strane lokalnih antigen-prezentujućih ćelija. Nakon reaktivacije, encefalitogene Th ćelije pokreću i održavaju inflamaciju unutar CNS-a. Albino oksford (AO) pacovi su veoma otporni na indukciju EAE-a. S druge strane, Dark Agouti (DA) pacovi razvijaju EAE čak i nakon blage imunizacije. U dosadašnjim istraživanjima je pokazano da se AO pacovi u odnosu na DA pacove razlikuju po slaboj aktivaciji Th1 i Th17 ćelija u relevantnim limfnim čvorovima u odgovoru na encefalitogenu imunizaciju. Takođe, pokazano je da relativno mali broj encefalitogenih ćelija infiltrira CNS AO pacova. Do sada nije vršeno ispitivanje uloge GALT-a i mikrobiote creva u otpornosti pacova soja AO na indukciju EAE-a. Sve je više istraživanja koja pokazuju da mikroorganizmi creva imaju važnu ulogu u regulaciji imunskog odgovora kroz interakciju sa limfnim tkivom creva (GALT, engl. gut-associated lymphoid tissue). U istraživanjima na EAE-u je pokazano da određeni mikroorganizmi creva pospešuju tok bolesti, dok drugi ostvaruju terapeutske efekte modulacijom odnosa Th1 i Th17 encefalitogenih ćelija i regulatornih T ćelija (Treg). Poznato je i da encefalitogene CD4+ T ćelije migriraju u GALT, uključujući mezenterične limfne čvorove i Pejerove ploče gde se mogu diferencirati u Treg...

Multiple sclerosis is a chronic inflammatory neurodegenerative demyelinating disease of the central nervous system (CNS). Etiology of multiple sclerosis is still unknown, but data are showing that gut microbiota plays an important role in the pathogenesis of this disease. Information about the significance of gut microbiota in CNS autoimmunity has been dominantly obtained in studies in experimental autoimmune encephalomyelitis (EAE), an animal model of multiple sclerosis. The autoimmune response against CNS starts in lymph nodes draining the site of immunization in EAE. There, CD4+ T cells are being activated and differentiated into Th1 (helper T cells) and Th17 cells that produce IFN-γ and IL-17, respectively. When Th cells arrive in the CNS, they are reactivated by local antigen-presenting cells. After the reactivation, these encephalitogenic T cells initiate and propagate CNS inflammation. Albino Oxford (AO) rats are highly resistant to EAE induction. On the other hand, Dark Agouti (DA) rats develop EAE even after the mild immunization. In our earlier studies it was shown that AO rats had less activated Th1 and Th17 cells in the relevant lymph nodes in response to encephalitogenic immunization, unlike DA rats. Also, it was shown that relatively small number of encephalitogenic cells infiltrated CNS in AO rats. Up until now, the studies of role of GALT and gut microbiota in resistance of AO rats in EAE induction have not been conducted. It has been increasingly appreciated that gut microbiota plays an important role in the regulation of the immune response through interaction with the cells of gut-associated lymphoid tissue (GALT). In EAE studies specific gut microorganisms have been proposed to promote the disease, while others have been shown to have therapeutic effects by modulating ratio and activity of encefalitogenic Th1 and Th17 cells and regulatory T cells (Treg). Encefalitogenic cells can also migrate to GALT, including mesenteric lymph nodes and Peyer’s patches, where they can be re-differentiated into Treg...