MiR-320a is downregulated in patients with myasthenia gravis and modulates inflammatory cytokines production by targeting mitogen-activated protein kinase 1.

Myasthenia gravis (MG) are T-cell dependent antibody-mediated autoimmune disorders, microRNAs are important regulators of human autoimmune disease pathogenesis. Here, we investigated the miRNAs expression profiles in MG for the first time and found that miR-320a was significantly downregulated in MG patients compared to normal healthy people. Meanwhile, pro-inflammatory cytokins in MG patients were overexpressed. Furthermore, we identified MAPK1 as a direct target of miR-320a. Downregulation of miR-320a induced the overexpression of pro-inflammatory cytokins through promoting COX-2 expression. This process was modulated by ERK/ NF-κB pathways. Taken together, our findings suggested that miR-320a could play a role in modulation of inflammatory cytokins production.