Abstract
M. avium subsp. paratuberculosis (MAP) is the causative pathogen of Johne’s disease, a chronic granulomatous enteritis that principally affects ruminants and can survive, proliferate and disseminate in macrophages. MicroRNAs (miRNAs) are important regulators of gene expression and can impact the processes of cells. To investigate the role of miRNAs in monocyte-derived macrophages (MDMs) during MAP infection, we used high-throughput sequencing technology to analyze small RNA libraries of MAP-infected and control MDMs. The results showed that a total of 21 miRNAs were differentially expressed in MDMs after MAP infection, and 8864 target genes were predicted. A functional analysis showed that the target genes were mainly involved in the MAPK signaling pathway, Toll-like receptor signaling pathway, NF-kappa B signaling pathway and apoptosis. In addition, using a dual-luciferase reporter assay, flow cytometry, and a small interfering (si)RNA knockdown assay, the role of miR-150 in regulating macrophage apoptosis by targeting the programmed cell death protein-4 (PDCD4) was demonstrated. These results provide an experimental basis to reveal the regulatory mechanism of MAP infection and suggest the potential of miRNAs as biomarkers for the diagnosis of Johne’s disease in bovines.
Highlights
Mycobacterium avium complex (MAC) is an important zoonotic pathogen that causes respiratory tract, lymph node, and soft tissue infections in healthy individuals [1]
We showed that miR-150 could affect cell apoptosis and that miR-150 inhibitor-induced cell apoptosis was reversed by silencing PDCD4 through siRNA
These results suggest that PDCD4 is a mediator of macrophage apoptosis regulation by miR-150 in RAW264.7 cells
Summary
Mycobacterium avium complex (MAC) is an important zoonotic pathogen that causes respiratory tract, lymph node, and soft tissue infections in healthy individuals [1]. M. avium is divided into four subspecies: M. avium subsp. MAP is the causative pathogen of Johne’s disease, a chronic granulomatous enteritis that principally affects ruminants. There is general consensus that MAP influences the apoptotic of bovine macrophages. At different stages of the infection, MAP may assume either pro- or anti- apoptotic roles [11]. Analysis of the host macrophage mRNA and miRNA expression profile during infection can illuminate the molecular mechanisms and host-pathogen interactions associated with Johne’s disease. The mRNA transcriptome of bovine monocyte-derived macrophage (MDM) response during MAP infection has been described [14,15]
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