| First Author | Koch M | Year | 2012 |
| Journal | Proc Natl Acad Sci U S A | Volume | 109 |
| Issue | 19 | Pages | E1153-62 |
| PubMed ID | 22509021 | Mgi Jnum | J:184687 |
| Mgi Id | MGI:5426081 | Doi | 10.1073/pnas.1116125109 |
| Citation | Koch M, et al. (2012) Induction of microRNA-155 is TLR- and type IV secretion system-dependent in macrophages and inhibits DNA-damage induced apoptosis. Proc Natl Acad Sci U S A 109(19):E1153-62 |
| abstractText | Helicobacter pylori is a gastric pathogen responsible for a high disease burden worldwide. Deregulated inflammatory responses, possibly involving macrophages, are implicated in H. pylori-induced pathology, and microRNAs, such as miR-155, have recently emerged as crucial regulators of innate immunity and inflammatory responses. miR-155 is regulated by Toll-like receptor (TLR) ligands in monocyte-derived cells and has been shown to be induced in macrophages during H. pylori infection. Here, we investigated the regulation of miR-155 expression in primary murine bone marrow-derived macrophages (BMMs) during H. pylori infection and examined the downstream mRNA targets of this microRNA using microarray analysis. We report TLR2/4- and NOD1/2-independent up-regulation of miR-155, which was found to be dependent on the major H. pylori pathogenicity determinant, the type IV secretion system (T4SS). miR-155 expression was dependent on NF-kappaB signaling but was independent of CagA. Microarray analysis identified known gene targets of miR-155 in BMMs during H. pylori infection that are proapoptotic. We also identified and validated miR-155 binding sites in the 3' UTRs of the targets, Tspan14, Lpin1, and Pmaip1. We observed that H. pylori-infected miR-155(-/-) BMMs were significantly more susceptible to cisplatin DNA damage-induced apoptosis than were wild-type BMMs. Thus, our data suggest a function for the prototypical H. pylori pathogenicity factor, the T4SS, in the up-regulation of miR-155 in BMMs. We propose the antiapoptotic effects of miR-155 could enhance macrophage resistance to apoptosis induced by DNA damage during H. pylori infection. |
