NF-κB repressing factor downregulates basal expression and mycobacterium tuberculosis induced IP-10 and IL-8 synthesis via interference with NF-κB in monocytes

Background: our previous study showed nf-κb repressing factor (nkrf) downregulates ip-10 and il-8 synthesis in the peripheral blood mononuclear cells and alveolar macrophages of tb patients with high bacterial loads. however,the mechanism underlying the repressive effect of nkrf is not fully understood. results: the levels of ip-10,il-8 and nkrf were significantly up-regulated in thp-1 cells treated with heated mycobacterium tuberculosis (h. tb). nkrf inhibited nf-κb-mediated ip-10 and il-8 synthesis and release induced by h. tb. the repressive effect of nkrf is mediated via interference with nf-κb (p65) binding and rna polymerase ii recruitment to promoter sites of ip-10 and il-8. conclusions: we have elucidated that direct contact with mtb induces ip-10,il-8 and a concomitant increase in nkrf in thp-1 cells. the up-regulated nkrf serves as an endogenous repressor for ip-10 and il-8 synthesis to hinder host from robust response to mtb infection. © 2014 huang et al.; licensee biomed central.