Macrophage Dicer promotes tolerogenic apoptotic cell clearance and immune tolerance by inhibiting pentose phosphate pathway activity

摘要

Dicer regulates immune-silent clearance of ACs and immune tolerance by inhibiting pentose phosphate pathway activity in macrophages. A In vitro cultured WT, Dicer1-C or Dicer1-CKO mouse peritoneal macrophages were incubated with pHrodo-labeled apoptotic thymocytes for the indicated times, and phagocytosis was analyzed by flow cytometry (n = 3). B Dexamethasone (Dex, 0.2 mg) was i.p. injected into 4-week-old WT or Dicer1-CKO mice, and after 24 h, the numbers of Annexin V+ apoptotic cells and CD68+ macrophages were analyzed by flow cytometry (n = 3). C In vitro cultured WT or Dicer1-CKO mouse peritoneal macrophages were incubated with apoptotic thymocytes for 24 h, and the mRNA expression of inflammatory cytokines in macrophages was measured by quantitative RT-PCR (n = 3). D–F In vitro cultured WT or Dicer1-CKO mouse peritoneal macrophages were incubated with apoptotic human Jurkat T cells for 6 h, and macrophage transcriptional profiles were assessed by mRNA sequencing (D, En = 3) or quantitative RT-PCR (F, n = 3). D KEGG enrichment plot of the pentose phosphate pathway (KO00030), as determined by Gene Set Enrichment Analysis (GSEA). E The expression of enriched genes in the pentose phosphate pathway, as determined by GSEA. F Validation of enriched genes in the pentose phosphate pathway by quantitative RT-PCR. G In vitro cultured WT or Dicer1-CKO mouse peritoneal macrophages were incubated with DHEA (1 μM), 6-AN (10 μM) or PBS for 24 h, and the phagocytosis of pHrodo-labeled apoptotic thymocytes was measured by flow cytometry (n = 3). H Serum concentrations of anti-dsDNA antibodies (ADAs) and anti-nuclear antibodies (ANAs) in WT and Dicer1-CKO mice of different ages were analyzed by ELISA (n = 6). I IgG and C3 levels in the kidneys of 60-week-old WT and Dicer1-CKO mice (n = 3, bar = 100 μm). J Kidney functions in 60-week-old WT and Dicer1-CKO mice (n = 6). K Schematic diagram of the role of macrophage Dicer in apoptotic cell clearance and immune tolerance. The results are expressed as the mean ± SEM, n.s. not statistically significant, *P < 0.05; **P < 0.01; ***P < 0.001; ****P < 0.0001, two-tailed Student’s t test for two groups (B, C, F, J), one-way (B, G, H) or two-way (A) ANOVA with Tukey’s post hoc test for multiple groups