hsa-miR-330-5p regulates serine palmitoyltransferase long chain base subunit 1 and augments host protective immune response against Leishmania donovani infection.

Leishmaniasis, caused by the protozoan parasites of the genus Leishmania, poses a significant global health challenge, particularly in the resource-limited regions where it causes high mortality. Regardless in the progress of treatment strategies, the emergence of drug resistance and limited efficacy requires the search of novel therapy and therapeutic targets. MicroRNAs, the crucial post-transcriptional regulators of gene expression, play critical roles in host-pathogen interactions. Here, we screened the miRNAs dysregulated during Leishmania donovani infection through literature search. hsa-miR-330-5p, one of the miRNAs which through human KEGG 2021 and Human Cyc 2016 analysis was found to be involved in multiple pathways including sphingolipid signaling pathway. Sphingolipids are important class of lipids involved in different cellular processes and therefore are the targets of many pathogens including Leishmania. hsa-miR-330-5p was found downregulated after 24 h of Leishmania donovani infection in THP-1 derived human macrophages. Target prediction of sphingolipid biosynthetic genes through in silico prediction tools showed 3 UTR of serine palmitoyltransferase long chain base subunit 1 to be a target of hsa-miR-330-5p. The in silico target prediction of hsa-miR-330-5p was validated by cloning the 3 UTR target sequence of gene, transfecting and performing luciferase assay in HEK 293 T cell line. Transfection of mimic of hsa-miR-330-5p reduced the luciferase activity which validated the in silico target prediction. Further, mimic of hsa-miR-330-5p inhibited the expression of the target gene, serine palmitoyltransferase long chain base subunit 1 and augmented the expression of pro-inflammatory cytokines in L. donovani infected THP-1 derived macrophages. Mimic of hsa-miR-330-5p also led to a significant reduction in the intracellular parasite burden in both THP-1 derived as well as primary human macrophages. This study has not only identified the sphingolipid biosynthesis regulatory miRNA but will also help in the development of novel and effective treatment strategy against leishmaniasis in future.