MicroRNA profiles of murine macrophages infected with different strains of Leptospira spp

Leptospirosis is a neglected zoonotic disease of global importance. Despite its prevalence, pathogenesis is still poorly understood. Recent discoveries have placed miRNAs in the regulation of the infection process of several bacterial diseases. Here, we suggest that post-transcriptional regulation, mediated by miRNAs, may play a role in host response to infection in leptospirosis in a species and virulence-specific manner. Four treatments were performed in triplicates in J774A.1 macrophages in vitro, as follows: non-infected control cells and cells infected with virulent, attenuated and saprophyte strains of Leptospira. Following 8h of infection, total RNA was extracted and 250 ng of total RNA (RIN 10) was used to evaluate the miRNA profile using the microarray Affymetrix® miRNA 4.1 Array strip. Raw intensity values were background corrected, log2 transformed and then quantile normalized by the software Expression Console (Affymetrix) using the Robust Multi-array Average (RMA) algorithm. Next, statistical analysis was performed in the TAC software (Affymetrix) by ANOVA (fold change ± 1.5, p <0.01).