Abstract:To explore the potential role and the underlying molecular mechanisms of miR-506-3p in BCG-infected inflammatory responses of macrophages. The BCG-infected RAW264.7 cell model was established. RT-PCR assay was performed to detect the expression of miR-506-3p and inflammatory cytokines TNF-α, IL-1β, IL-6 and iNOS. ELISA assay was conducted to measure the level of inflammatory mediators. Griess assay was apply to evaluate the production of NO. The BCG survival was assessed using colony-forming unit (CFU) assay. Dual-luciferase reporter assay system, Western blot and RT-PCR were used to confirm the interaction between the miR-506-3p and 3′-UTR of SOCS-3.We observed that the expression of miR-506-3p was declined in a time-dependent manner in BCG-stimulated RAW264.7 cells. In addition, overexpression of miR-506-3p remarkably enhanced the accumulation of inflammatory cytokines TNF-α, IL-1β and IL-6 in BCG-infected RAW264.7 cells. Meanwhile, introduction of miR-506-3p obviously increased NO production and iNOS expression in BCG-challenged RAW264.7 cells. Moreover, introduction of miR-506-3p inhibited BCG survival. More importantly, the dual-luciferase reporter assay system, RT-PCR and Western Blot assay demonstrated that miR-506-3p could suppress SOCS-3 expression by targeting the specific 3′-UTR sequence of SOCS-3 gene. These findings demonstrated that miR-506-3p enhanced BCG-triggered inflammatory responses and suppressed BCG survival in BCG-infected macrophages by targeting SOCS-3, which may provide a promising therapeutic target for Tuberculosis treatment.
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