Expression of MicroRNA of Macrophages Infected with Attenuated Leishmania major Parasite

Objective Leishmaniasis has been proposed as one of the neglected vector-borne diseases due to an obligate intracellular parasite of the genus Leishmania. MicroRNAs (miRNAs) with a length of 22-nucleotide are known as the noncoding small RNAs. MiRNAs contribute to many biological and cellular approaches. Therefore, the present study evaluated expressing mmu-miR-721, mmu-miR-294–3p, mmu-miR-155–3p, and mmu-miR-30a in murine macrophages infected with attenuated Leishmania major parasites on 3 days after infection. Methods Attenuated promastigotes have been achieved after 20 passages of Leishmania major parasites. Cell line J774A.1 (murine macrophage) has been used for in vitro experiments. The stationary phase of attenuated L. major promastigotes has been chosen to infect the cells, and then their incubation has been performed with 5% CO2 at 37°C for 3 days. The real-time polymerase chain reaction (PCR) has also been performed with SYBR Green master-mix Kit for measuring the level of mmu-miR-721, mmu-miR-294–3p, mmu-miR-30a, and mmu-miR-155-3p expression. Uninfected macrophages have been considered as a control group. Results Real-time PCR demonstrated overexpression of mmu-miR-155-3p, mmu-miR-294–3p, and, mmu-miR-721 in the infected cells with Leishmania parasites after 3 days. Results showed no statistically significant difference in the mmu-miR-30a expression between infected macrophages and the uninfected control group. Conclusion Our findings suggested the significant contribution of the alterations in the miRNA levels to the regulation of macrophage functions following the creation of intracellular parasites like Leishmania. These data could help to understand better the genes' expression in the host cells in the course of leishmaniasis.