The innate immune response is vital in an organism’s ability to fight infection. Aspects of the innate immune response including inflammation, phagocyte populations, and the production of reactive oxygen species (ROS) must be closely regulated in order to effectively eliminate pathogenic entities. Dysregulation of the innate immune response can cause various pathologies, including chronic infection, autoimmunity, and cancer. Recent studies have shown that microRNAs (miRs) play a regulatory and “fine-tuning” role in the innate immune system of the Zebrafish.99 We have found that the expression of miR-199 is significantly upregulated upon stimulation of the Zebrafish innate immune system with Pseudomonas aeruginosa infection. Knocking-down the expression of miR-199 using oligonucleotide morpholino injection led to a significant decrease in bacterial burden of fish infected with P. aeruginosa as well as a significant increase in overall survival. Overexpression of miR-199 using a mature miR-199 duplex led to a decrease in overall reactive oxygen species (ROS) within an infected organism. Recent data also suggest that direct targeting of Src family kinase (SFK) Lyn by miR-199 may be responsible for the immunosuppressant characteristics of this specific microRNA.
Gagné, Eliot Rivers, "Regulation of microRNA-199 Upon Pseudomonas Aeruginosa Infection in Zebrafish" (2016). Honors College. 383.