Fig. 2: STING-dependent inflammation after MGME1 loss.
From: Ribonucleotide incorporation into mitochondrial DNA drives inflammation
a, Agglomerative heat map showing the z-score-normalized mRNA ISG intensities in kidneys of 55-week-old Mgme1−/− and Mgme1−/−Sting1mut/mut mice obtained by NanoString profiling. Each column represents a different mouse (left). Heat map (log2-transformed fold change, decreasing order) of mRNA ISG profiles obtained by NanoString profiling in kidneys of 55-week-old Mgme1−/− and Mgme1−/−Sting1mut/mut mice (right). The asterisks mark ISGs of which the expression was significantly altered. n = 6 mice per genotype. b, dPCR data of mtDNA levels in the cytosolic fractions of immortalized Mgme1+/+ and Mgme1−/− MEFs. The cytosolic mtDNA copy number was normalized to protein mass. n = 4 independent cultures. c, Localization of mtDNA foci determined by immunofluorescence analysis of immortalized MEFs. Mgme1+/+ and Mgme1−/− cells were stained with antibodies against mitochondrial TOMM20 (green), pyruvate dehydrogenase (PDH) (grey) and double-stranded DNA (red). The arrows indicate non-mitochondrial mtDNA foci. Scale bars, 10 μm. d, Quantification of the immunofluorescence analysis shown in c. n = 150 cells. e, Representative images of the renal cortex sections stained with periodic acid–Schiff (PAS), and immunohistochemistry analysis (CD3 and B220 (CD45R)) of kidney sections from control (Mgme1+/+), Mgme1−/−, Sting1mut/mut and Mgme1−/−Sting1mut/mut mice. The yellow asterisks indicate regions of sclerosis within the glomerulus, the yellow arrows indicate immune cell infiltrates and the yellow arrowhead indicates proteinaceous casts. The orange arrows indicate CD3+ T cells and B220+ B cells (middle and bottom). Scale bars, 20 μm. Assessment of glomerulosclerosis, the percentages of sclerosed glomeruli and quantification of immune cell infiltration are shown on the right. n = 12 (Mgme1+/+), n = 4 (Sting1mut/mut), n = 12 (Mgme1−/−) and n = 13 (Mgme1−/−Sting1mut/mut) mice. P values were calculated using unpaired two-tailed Student t-tests (b) with Welch’s correction (d) or using one-way analysis of variance (ANOVA) with Tukey’s multiple-comparison test (e). Data are mean ± s.d. (b and d) and mean ± s.e.m. (e). *q < 0.05, **q < 0.01 (a).
