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microRNA-148a regulates inflammatory cytokines and microbicidal activity in canine leishmaniasis

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Gabriela Torres Rebech
Total Authors: 1
Document type: Doctoral Thesis
Press: Araçatuba. 2022-04-20.
Institution: Universidade Estadual Paulista (Unesp). Faculdade de Medicina Veterinária. Araçatuba
Defense date:
Advisor: Valéria Marçal Felix de Lima

Canine leishmaniasis (CanL) is a serious public health concern, because infected animals facilitate transmission of the Leishmania protozoan to humans by the bite of sandfly vector during the blood meal. Progression of CanL is related to effective suppression of immune response, possibly associated with small RNAs called microRNAs (miR), which can affect mRNA translation into proteins and, consequently, regulate cells function. The increase of miR-148a in splenic leukocytes (SL) of dogs with CanL was observed in previous studies and in silico analysis identified possible pathways involved in immune response regulation that are affected by this miR. Therefore, through the use of, in vitro, cell culturing and transfection, we evaluated the involvement of miR-148a, in regulation of inflammatory cytokines such as TNF-α, IL-6, IL-12, IL-1β, iNOS, MHCII expression, CD80, CD3, of the T-bet (Th1) and GATA-3 (Th2) transcription factors and their relationship with parasite load in SL of dogs with CanL. Primary, SL obtained from healthy and diseased dogs (CanL), were transfectedwith miR-148a mimic and inhibitor inventoried oligonucleotides. After 48 hours, expression of MHCII, CD80, iNOS, CD3, Tbet, GATA-3 proteins was evaluated by flow cytometry and concentration of TNF-α, IL-12, IL-6 and IL-1β was measured in culture supernatant by capture ELISA. Transfection of SL with miR-148a mimic decreased iNOS concentration in the cells and TNF-α, IL-6 and IL-12 in the supernatant of the cultured SL from CanL dogs. Interestingly, transfection with miR-148a inhibitor decreased parasite load in cells. These results suggest a negative regulatory role of this miR in immune response to L. infantum infection. We conclude that miR-148a can affect immune response by regulating inflammatory cytokines during CanL. Our results contribute to the understanding of the complex host/parasite interaction in canine leishmaniasis and could assist the development of possible treatments. (AU)

FAPESP's process: 19/04240-2 - MiRNA148a in immune response regulation of splenic leukocytes in Visceral Canine Leishmaniasis
Grantee:Gabriela Torres Rebech
Support Opportunities: Scholarships in Brazil - Doctorate