Dataset Information

RNY (YRNA)-derived small RNAs regulate cell death and inflammation in monocytes/macrophages.

ABSTRACT: The recent discovery of new classes of small RNAs has opened unknown territories to explore new regulations of physiopathological events. We have recently demonstrated that RNY (or Y RNA)-derived small RNAs (referred to as s-RNYs) are an independent class of clinical biomarkers to detect coronary artery lesions and are associated with atherosclerosis burden. Here, we have studied the role of s-RNYs in human and mouse monocytes/macrophages and have shown that in lipid-laden monocytes/macrophages s-RNY expression is timely correlated to the activation of both NF-?B and caspase 3-dependent cell death pathways. Loss- or gain-of-function experiments demonstrated that s-RNYs activate caspase 3 and NF-?B signaling pathways ultimately promoting cell death and inflammatory responses. As, in atherosclerosis, Ro60-associated s-RNYs generated by apoptotic macrophages are released in the blood of patients, we have investigated the extracellular function of the s-RNY/Ro60 complex. Our data demonstrated that s-RNY/Ro60 complex induces caspase 3-dependent cell death and NF-?B-dependent inflammation, when added to the medium of cultured monocytes/macrophages. Finally, we have shown that s-RNY function is mediated by Toll-like receptor 7 (TLR7). Indeed using chloroquine, which disrupts signaling of endosome-localized TLRs 3, 7, 8 and 9 or the more specific TLR7/9 antagonist, the phosphorothioated oligonucleotide IRS954, we blocked the effect of either intracellular or extracellular s-RNYs. These results position s-RNYs as relevant novel functional molecules that impacts on macrophage physiopathology, indicating their potential role as mediators of inflammatory diseases, such as atherosclerosis.

SUBMITTER: Hizir Z

PROVIDER: S-EPMC5386355 | biostudies-literature | 2017 Jan

REPOSITORIES: biostudies-literature

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RNY (YRNA)-derived small RNAs regulate cell death and inflammation in monocytes/macrophages.

Hizir Zoheir Z Bottini Silvia S Grandjean Valerie V Trabucchi Michele M Repetto Emanuela E

Cell death & disease 20170105 1

The recent discovery of new classes of small RNAs has opened unknown territories to explore new regulations of physiopathological events. We have recently demonstrated that RNY (or Y RNA)-derived small RNAs (referred to as s-RNYs) are an independent class of clinical biomarkers to detect coronary artery lesions and are associated with atherosclerosis burden. Here, we have studied the role of s-RNYs in human and mouse monocytes/macrophages and have shown that in lipid-laden monocytes/macrophages ...[more]

PMID: 28055017

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Project description:Monocytes consist of two well-defined subsets, the Ly6C+ and Ly6C- monocytes. Both CD11b+ myeloid cells populations have been proposed to infiltrate tissues during inflammation. While infiltration of Ly6C+ monocytes is an established pathogenic factor during hepatic inflammation, the role of Ly6C- monocytes remains elusive. Mice suffering experimental African trypanosome infection die from systemic inflammatory response syndrome (SIRS) that is initiated by phagocytosis of parasites by liver myeloid cells and culminates in apoptosis/necrosis of liver myeloid and parenchymal cells that reduces host survival. C57BL/6 mice are considered as trypanotolerant to Trypanosoma congolense infection. We have reported that in these animals, IL-10, produced among others by myeloid cells, limits the liver damage caused by pathogenic TNF-producing Ly6C+ monocytes, ensuring prolonged survival. Here, the heterogeneity and dynamics of liver myeloid cells in T. congolense-infected C57/BL6 mice was further dissected. Moreover, the contribution of Ly6C- monocytes to trypanotolerance was investigated. By using FACS analysis and adoptive transfer experiments, we found that the accumulation of Ly6C- monocytes and macrophages in the liver of infected mice coincided with a drop in the pool of Ly6C+ monocytes. Pathogenic TNF mainly originated from Ly6C+ monocytes while Ly6C- monocytes and macrophages were major and equipotent sources of IL-10 within myeloid cells. Moreover, Nr4a1 (Nur77) transcription factor-dependent Ly6C- monocytes exhibited IL-10-dependent and cell contact-dependent regulatory properties contributing to trypanotolerance by suppressing the production of TNF by Ly6C+ monocytes and by promoting the differentiation of the latter cells into macrophages. Thus, Ly6C- monocytes can dampen liver damage caused by an extensive Ly6C+ monocyte-associated inflammatory immune response in T. congolense trypanotolerant animals. In a more general context, Ly6C- or Ly6C+ monocyte targeting may represent a therapeutic approach in liver pathogenicity induced by chronic infection.

Dataset Information

RNY (YRNA)-derived small RNAs regulate cell death and inflammation in monocytes/macrophages.

Publications

RNY (YRNA)-derived small RNAs regulate cell death and inflammation in monocytes/macrophages.

Similar Datasets

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