Monocarboxylate transporter 4 facilitates survival through NF-κB p65-mediated interleukin-10 production.

Tuberculosis (TB) is a chronic infectious disease caused by (Mtb) infection, with the highest single-cause mortality. Monocarboxylate transporter 4 (Mct4) transports intracellular lactate outside, but its role in regulating host immune response against Mtb infection remains unknown. Mct4 expression was upregulated in Mtb-infected macrophages and in patients with TB. Mct4 silencing/deficiency significantly decreased Mtb survival in macrophages and in lungs and spleens of mice, while Mct4 overexpression facilitated Mtb survival in macrophages. Furthermore, Mct4 promoted intracellular lactate transport, nuclear factor κB (NF-κB) p65 activation, and interleukin-10 (IL-10) production upon Mtb infection. Mechanistically, IL-10 silencing and IL-10-neutralizing antibody blocked Mct4 overexpressing increased Mtb survival. Replenishing lactate and NF-κB p65 inhibitor JSH23 treatment could inhibit Mct4 overexpressing increased NF-κB p65 activation, IL-10 production, and Mtb survival in macrophages. This study demonstrates that Mct4 promotes Mtb survival through restricting intracellular lactate accumulation to promote NF-κB p65-mediated IL-10 production and suggests Mct4-NF-κB p65-IL-10 axis a potential target for TB treatment.