Efekat primene etil-piruvata na razvoj dijabetesa tipa 1 kod C57BL/6 miševa

Abstract

Dijabetes tipa 1 (DT1) je autoimunska bolest koja podrazumeva inflamaciju u pankreasu i smrt β ćelija, što kao posledicu ima smanjenje nivoa insulina, a povećanje nivoa glukoze u krvi. S obzirom na to da lek za DT1 još nije pronađen i da se obolele osobe oslanjaju na doživotni tretman insulinom, konstantni napori se ulažu u razvoj novih terapijskih pristupa. U tom cilju, u ovoj doktorskoj disertaciji je ispitivano dejstvo etil-piruvata, koji ima potvrđena antiinflamacijska svojstva, na razvoj DT1 u modelu bolesti na C57BL/6 miševima kojim je DT1 hemijski izazvan primenom višestrukih malih doza streptozotocina. Njegova profilaktička primena u navedenom modelu DT1 je dovela do smanjenja incidence bolesti, što je bilo praćeno manjom infiltracijom imunskih ćelija u pankreasna ostrvca i smanjenjem ekspresije primarnog ciljnog molekula etil-piruvata, HMGB1 (engl. High Mobility Group Box 1). Mehanizmi protektivnog dejstva etil-piruvata su obuhvatali stimulaciju regulatorne grane imunskog odgovora, tj. uvećanje udela tolerogenih dendritskih ćelija i regulatornih T (Treg) ćelija. Efekat etil-piruvata na Treg ćelije je podrazumevao njihovu uvećanu proliferaciju, diferencijaciju, migraciju i supresivnu funkciju i to prevashodno prema efektorskim T-bet+ T limfocitima. Pored uticaja na Treg ćelije u patološkim uslovima, etil-piruvat je ostvario stimulatorni efekat na ove ćelije i u homeostatskim uslovima, bilo da je primenjivan oralno ili intraperitonelano. Komplementarna in vitro istraživanja su pokazala da etil-piruvat ostvaruje svoj potencirajući uticaj na proliferaciju Treg ćelija, i to modulisanjem ćelijskog metabolizma putem stimulacije glikolize i inhibicije β-oksidacije masnih kiselina, dok je uticaj na Krebsov ciklus i oksidativnu fosforilaciju potpuno izostao. Rezultati ove doktorske disertacije ukazuju na značajan potencijal koji etil-piruvat ima u smirivanju inflamacije, ključnog efektorskog mehanizma tokom DT1, te da se njegova primena u lečenju DT1 može istraživati u budućim prekliničkim i kliničkim studijama.

Type 1 diabetes (T1D) is an autoimmune disease which triggers inflammation in the pancreas and the death of pancreatic β-cells, resulting in a decrease in insulin levels and increase of blood glucose levels. Since a cure for T1D still hasn’t been found and patients with T1D rely on a life-long insulin treatment, constant efforts are invested to develop new therapeutical approaches. To that end, this doctoral thesis was devoted to testing the effects of ethyl pyruvate, known to have anti-inflammatory properties, on the development of T1D, induced by multiple low-doses of streptozotocin, in C57BL/6 mice. Its prophylactic application in the aforementioned T1D model resulted in decreased disease incidence, accompanied by lessened immune cell infiltration into the pancreatic islets and reduced expression of the primary target molecule of ethyl pyruvate, HMGB1 (High Mobility Group Box 1). Ethyl pyruvate accomplished its protective influence by stimulating the regulatory arm of the immune response, namely by increasing the proportion of tolerogenic dendritic cells and regulatory T (Treg) cells. It also exerted its effects on Treg cells by increasing their proliferation, differentiation, migration and suppressive function, primarily towards effector T-bet+ T cells. Aside from its effects on Treg cells in pathological conditions, ethyl pyruvate stimulated Treg cells in homeostatic conditions, whether applied orally or intraperitoneally. Complementary in vitro experiments showed that ethyl pyruvate potentiates Treg cell proliferation, which is achieved through the modulation of cell metabolism, by stimulating glycolysis and suppressing fatty acid β-oxidation, while there is no effect on the citric acid cycle or oxidative phosphorylation. The results of this doctoral thesis indicate a notable potential of ethyl pyruvate to inhibit inflammation, a key part of T1D pathology, and that its application in T1D therapy can be further explored in preclinical and clinical studies