Macrophages are mainly divided into two populations, which play a different role in physiological and pathological conditions. The differentiation of these cells may be regulated by transcription factors. However, it is unclear how to modulate these transcription factors to affect differentiation of these cells. Here, we found that lncLy6C, a novel ultraconserved lncRNA, promotes differentiation of Ly6Chigh inflammatory monocytes into Ly6Clow/neg resident macrophages. We demonstrate that gut microbiota metabolites butyrate upregulates the expression of lncLy6C. LncLy6C deficient mice had markedly increased Ly6Chigh pro-inflammatory monocytes and reduced Ly6Cneg resident macrophages. LncLy6C not only bound with transcription factor C/EBPβ but also bound with multiple lysine methyltransferases of H3K4me3 to specifically promote the enrichment of C/EBPβ and H3K4me3 marks on the promoter region of Nr4A1, which can promote Ly6Chigh into Ly6Cneg macrophages. As a result, lncLy6C causes the upregulation of Nr4A1 to promote Ly6Chigh inflammatory monocytes to differentiate into Ly6Cint/neg resident macrophages.
Background: Programmed cell death protein 1 (PD-1), as an immune checkpoint cell membrane receptor, negatively regulates T cell activation via its immune receptor, the tyrosine-based switch motif (ITSM). The purpose of this research was to evaluate the antitumor activity T cells with the ITSM mutation of PD-1 on non-small cell lung cancer (NSCLC) in vitro and in vivo.Methods: In this study, the tyrosine of ITSM in cytotoxic T cells was mutated using the adenine base editor (ABE)-xCas9 system to evaluate its effect on the antitumor activity of T cells against NSCLC. Results: Results showed that the PD-1-deficient T cells enhanced the death of the cocultured NSCLC cells compared with the normal T cells and saline solution. PD-1-deficient T cells also changed the interleukin 2(IL-2), interferon γ (IFN-γ), tumor necrosis factor α (TNF-α), and granulocyte-macrophage colony-stimulating factor (GM-CSF) secretion of T cells compared with those of the normal T cells. The effectiveness of ITSM mutation in enhancing the antitumor activity of PD-1-deficient T cells was verified in vivo by using a mouse xenograft model. The xenografted mice treated with PD-1-deficient T cells demonstrated repressed tumor growth of the NSCLC cells compared with those treated with normal T cells and saline solution. Conclusions: The mutation of ITSM in cytotoxic T cell via the ABE-xCas9 system can significantly enhance the antitumor activity of T cells.
Myeloid-derived suppressor cells (MDSCs) are pathologically activated neutrophils and monocytes with potent immunosuppressive activity that regulate immune responses in the tumor microenvironment. We identified a novel long noncoding RNA (lncRNA), named as lnc57Rik, in the MDSCs that controls their immunosuppressive functions. Lnc57Rik was induced in in vitro and in vivo inflammatory settings and upregulated the genes related to MDSC-mediated immunosuppression, including Arg-1, NOS2, NOX2, and COX2. Furthermore, Lnc57Rik can not only bind with the C/EBPβ isoform liver-enriched activator protein to activate C/EBPβ but also with the methyltransferase WD repeat-containing protein 5 that enables the enrichment of histone H3 trimethylated lysine 4 marks on the promoter regions of Arg-1, NOS2, NOX2, and COX2, eventually resulting in their transcriptional activation. Furthermore, the conserved human lnc57Rik has a similar function as murine lnc57Rik. Taken together, upregulation of lnc57Rik in the tumor microenvironment promotes the immunosuppressive function of MDSCs.
The activation of NLRC4 is a major host response against the infection by intracellular bacteria. However, there still remain challenges in understanding the activation upon sensing of diverse stimuli. We here found that lncRNA LNCGM1082 plays a critical role in the activation of NLRC4. LNCGM1082 in macrophages could affect maturation of interleukin (IL)-1β and pyroptotic cell death only after exposed to NLRC4 ligand. Similar to NLRC4-/mice, LNCGM1082-/mice were high sensitive to Salmonella typhimurium infection. LNCGM1082 de ciency in mouse or human macrophages had reduced IL-1β maturation and pyroptosis. Mechanistically, LNCGM1082 could induce the combination of PKCδ with NLRC4 in both mice and human. There was absence of binding of NLRC4 with PKCδ in LNCGM1082-/macrophages. This lncRNA could be induced by Salmonella typhimurium through TLR5 in the macrophages of both mice and human. Thus, our data indicate that LNCGM1082 induced by TLR5 can mediate the binding of PKCδ with NLRC4 to cause the activation of NLRC4.
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