Transcriptional regulators SP110 and SP140 modulate inflammatory response genes in Mycobacterium...

Understanding the functions of human transcriptional regulatory genes SP110 and SP140 during Mycobacterium tuberculosis infection is crucial; in a mouse model, homologous genes Sp110 and Sp140 have been shown to negatively regulate inflammatory response genes, including the type I interferon (IFN) response. The reduction of these genes in mice is associated with susceptibility to M. tuberculosis infection and the development of necrotizing granulomatous lesions. To investigate the involvement of SP110 and SP140 in human inflammatory response, we analyzed their regulatory manner in THP-1 macrophages infected with M. tuberculosis. Genome-wide transcriptional profiling revealed that the depletion of SP110 and/or SP140 impaired the induction of gene expression associated with inflammatory responses, including IFN response genes, although it had little effect on the intracellular proliferation of M. tuberculosis. By contrast, genes related to phosphorylation were upregulated in infected macrophages with SP110 and/or SP140 knockdown, but downregulated in infected control macrophages without their knockdown. Reverse transcription-quantitative PCR and ELISA further confirmed the impairment of the induction of IFN response genes by the depletion of SP110 and/or SP140 in M. tuberculosis-infected macrophages. These findings suggest that human SP110 and SP140 act as positive regulators for genes associated with inflammatory responses in M. tuberculosis-infected macrophages.

Tuberculosis (TB) is one of the most serious infectious diseases, with high morbidity and mortality worldwide. C3HeB/FeJ mice are widely utilized for evaluating anti-TB drugs because their drug sensitivity and pathology during M. tuberculosis infection resemble those of human TB, including the development of necrotizing granulomas. Downregulation of the transcriptional regulatory genes Sp110 and Sp140 in C3HeB/FeJ mice has been demonstrated to activate gene expression associated with inflammatory responses during M. tuberculosis infection, resulting in susceptibility to the infection. Here, we examined the regulatory manner of SP110 and SP140 using transcriptomic analysis in M. tuberculosis-infected human macrophages. Depletion of SP110 and/or SP140 in M. tuberculosis-infected THP-1 macrophages impaired the induction of gene expression associated with inflammatory responses, including interferon response genes, compared with that in control macrophages. These results suggest that human SP110 and SP140 act as positive regulators for genes associated with inflammatory responses upon M. tuberculosis infection.