MicroRNA-325-3p Facilitates Immune Escape of Mycobacterium tuberculosis through Targeting LNX1 via NEK6 Accumulation to Promote Anti-Apoptotic STAT3 Signaling

Abstract

Tuberculosis (TB) is an infectious disease caused by Mycobacterium tuberculosis that poses threats to the public. M. tuberculosis survives in macrophages by escaping from immune surveillance and clearance, which exacerbates the bacterial proliferation. However, the molecular mechanisms of this immune escape have not yet been fully understood. Using multiple cell and mouse models, we found that microRNA-325-3p (miR-325-3p) is upregulated after M. tuberculosis infection and Mir325-deficient mice show resistance to M. tuberculosis. We demonstrated that miR-325-3p directly targets LNX1, an E3 ubiquitin ligase of NEK6, and that this hampers the proteasomal degradation of NEK6 in macrophages. The abnormal accumulation of NEK6 leads to the activation of STAT3 signaling, thus inhibiting the process of apoptosis and promoting the intracellular survival of M. tuberculosis. Our findings not only reveal a new immune escape pathway of M. tuberculosis but also may provide new insights into the development of therapeutic approaches for drug-resistant TB. IMPORTANCE Intracellular survival of Mycobacterium tuberculosis results in bacterial proliferation and the spread of infection in lungs, consequently deteriorating the conditions of tuberculosis (TB) patients. This research discovers a new immune escape pathway of M. tuberculosis by modulating host miR-325-3p expression, thus leading to the intracellular survival of M. tuberculosis. These findings make a contribution to the understanding of the immune escape of M. tuberculosis, and they provide a theoretical basis for the development of therapeutic approaches for drug-resistant TB.

MiR‐325‐3p inhibits renal inflammation and fibrosis by targeting CCL19 in diabetic nephropathy

“…14 MiR-325-3p targets LNX1 via NEK6 accumulation to facilitate immune escape of Mycobacterium tuberculosis, thus promoting the STAT3 signalling. 15 However, neither the biological function nor the regulatory mechanism of miR-325-3p has been investigated in DN. C-C motif chemokine ligand 19 (CCL19) belongs to the protein family of chemokines, which can regulate various diseases.…”

Tuberculosis-Associated MicroRNAs: From Pathogenesis to Disease Biomarkers

“…MiR-29a-3p and miR-125-5p, both upregulated in infected macrophages, directly target IFNγ and TNFα, hence suppressing the immune response to intracellular M. tuberculosis [ 24 , 25 ]. Cell apoptosis and inflammasome induction are other mechanisms of defense against intracellular pathogens, which are regulated by M. tuberculosis -modulated host miRNAs, like miR-325-3p and miR-20b-5p [ 26 , 27 ]. On the other hand, some miRNAs, like miR-155-5p and let-7f, which are modulated in the course of M. tuberculosis infection, play a key role in the activation of host innate and adaptive immunity and clearance of bacteria [ 28 , 29 , 30 ].…”

“…MiR-325-3p is upregulated in experimental M. tuberculosis infection in mice and macrophages and in patients with LTBI [ 26 ]. MiR-325-3p upregulation occurs also after exposure of macrophages to gamma-irradiated M. tuberculosis but not after infection with M. bovis BCG, which lacks the RD1 genomic region of pathogenicity [ 26 ]. Macrophages with silenced miR-325-3p and miR-325-deficient mice show resistance to M. tuberculosis, thus indicating that miR-325-3p promotes M. tuberculosis persistence and latency in the host.…”

“…MiR-325-3p directly targets LNX1 , which encodes an E3 ubiquitin ligase of the serine/threonine protein kinase NEK6. In macrophages, M. tuberculosis leads to LNX1 downregulation and hence NEK6 accumulation, which in turn inhibits apoptosis through activation of STAT3 signaling [ 26 ]. Conversely, suppression of the NEK6/STAT3 pathway reduces bacterial burden and improves survival of M. tuberculosis infected mice [ 26 ].…”

PTPN14 aggravates inflammation through promoting proteasomal degradation of SOCS7 in acute liver failure

“…The culture medium was composed of Dulbecco's Modified Eagle's Medium (DMEM, Gibco, San Jose, CA, USA) and 10% fetal bovine serum (Gibco). BMDMs were obtained by culturing bone marrow cells as previously described 28 . After 6 days of culture, adherent macrophages were switched into antibiotic-free media and seeded with 10 5 cells per well.…”