MIR144* inhibits antimicrobial responses against Mycobacterium tuberculosis in human monocytes and macrophages by targeting the autophagy protein DRAM2

Abstract

Autophagy is an important antimicrobial effector process that defends against Mycobacterium tuberculosis (Mtb), the human pathogen causing tuberculosis (TB). MicroRNAs (miRNAs), endogenous noncoding RNAs, are involved in various biological functions and act as post-transcriptional regulators to target mRNAs. The process by which miRNAs affect antibacterial autophagy and host defense mechanisms against Mtb infections in human monocytes and macrophages is largely uncharacterized. In this study, we show that Mtb significantly induces the expression of MIR144*/hsa-miR-144-5p, which targets the 3'-untranslated region of DRAM2 (DNA damage regulated autophagy modulator 2) in human monocytes and macrophages. Mtb infection downregulated, whereas the autophagy activators upregulated, DRAM2 expression in human monocytes and macrophages by activating AMP-activated protein kinase. In addition, overexpression of MIR144* decreased DRAM2 expression and formation of autophagosomes in human monocytes, whereas inhibition of MIR144* had the opposite effect. Moreover, the levels of MIR144* were elevated, whereas DRAM2 levels were reduced, in human peripheral blood cells and tissues in TB patients, indicating the clinical significance of MIR144* and DRAM2 in human TB. Notably, DRAM2 interacted with BECN1 and UVRAG, essential components of the autophagic machinery, leading to displacement of RUBCN from the BECN1 complex and enhancement of Ptdlns3K activity. Furthermore, MIR144* and DRAM2 were critically involved in phagosomal maturation and enhanced antimicrobial effects against Mtb. Our findings identify a previously unrecognized role of human MIR144* in the inhibition of antibacterial autophagy and the innate host immune response to Mtb. Additionally, these data reveal that DRAM2 is a key coordinator of autophagy activation that enhances antimicrobial activity against Mtb.

MicroRNA in innate immunity and autophagy during mycobacterial infection

“…However, there was no difference in miR-144* levels between TB patients and healthy controls in that study (Kleinsteuber et al, 2013). Our recent studies showed that MIR144* levels were upregulated in PBMCs and disease sites from active TB patients, compared with healthy controls (Kim et al, 2016).…”

“…However, there was no difference in miR‐144* levels between TB patients and healthy controls in that study (Kleinsteuber et al, ). Our recent studies showed that MIR144* levels were upregulated in PBMCs and disease sites from active TB patients, compared with healthy controls (Kim et al, ). Further biological analyses showed that MIR144* targeting DRAM2, an autophagy and lysosomal protein, contributed to the pathogenesis of TB by autophagic inhibition controls (Kim et al, 2016).…”

Assessment of microRNA‐144‐5p and its putative targets in inflamed gingiva from chronic periodontitis patients

“…miR‐144‐5p, first discovered to be a potential biomarker of follicular thyroid cancer, may also be a regulatory factor in various disease, including metabolic disease (metabolic syndrome and diabetes), malignant tumour (non‐small‐cell lung cancer, breast cancer, bladder cancer, oesophageal carcinoma and gastric cancer), inflammatory diseases (tuberculosis, obesity and amyotrophic lateral sclerosis), Alzheimer's disease, depressive disorders and coronary syndrome . miR‐144‐5p inhibited antibacterial autophagy and the immune response to Mycobacterium tuberculosis via repressing DNA damage‐regulated autophagy modulator 2, which is a coordinator of antimicrobial autophagy …”

MicroRNAs play an essential role in autophagy regulation in various disease phenotypes

“…MIR144 plays a role in the inhibition of autophagy induction and autophagic flux. Overexpression of MIR144 decreased DRAM2 expression and formation of autophagosomes in human monocytes, suggesting the clinical significance of MIR144‐DRAM2 in TB infection . KLF4 tilts the macrophage response toward the production of arginase and inhibition of autophagy.…”

“…Overexpression of MIR144 decreased DRAM2 expression and formation of autophagosomes in human monocytes, suggesting the clinical significance of MIR144-DRAM2 in TB infection. 126 KLF4 tilts the macrophage response toward the production of arginase and inhibition of autophagy. miR-26a/KLF4 and CREB-C/EBPβ signaling pathways play crucial roles in regulating the survival of MTB in macrophages, including regulating innate immune signaling, the polarization of macrophages, and the trafficking of Mycobacterium tuberculosis to lysosomes during infection.…”