Expression of miRNAs and polarization of microglia in the brain of dogs with leishmaniasis

Abstract

Canine visceral leishmaniasis (CanL) is a chronic, invariably progressive disease with high clinical variability, including neurological disorders. Despite the clinical importance of the disease for humans and dogs, there are still few reports that characterize neurological lesions in visceral leishmaniasis (VL) and explain its pathogenesis. Previous studies carried out in dogs with VL showed the presence of brain inflammation, including meningitis and choroiditis, activation of glial cells, in addition to the activation of metalloproteinases, in addition to changes in the gene expression of pro-inflammatory chemokines and cytokines. The balance between different phenotypic states of microglia and astrocytes can promote inflammation or tissue repair and influence the progression of inflammatory disorders of nervous tissue. MiRNAs operate by activating or modulating glial cells, and can promote or restrict inflammatory signaling, exacerbating or ameliorating the consequences of an inflammatory process in nervous tissue. Thus, in continuity with previous projects that used the dog as a model, the present study seeks to better understand the pathogenesis of the neurological alterations caused by CanL through the evaluation of miRNA expression related to microglial activation and modulation (M1/M2) and the functional profile of astrocytes in the brains of naturally infected dogs. (AU)