Journal: The Journal of Clinical Investigation
Article Title: Aspartate deficiency amplifies cGAS-STING signaling in antitumor immunity
doi: 10.1172/JCI199716
Figure Lengend Snippet: ( A ) Schematic showing that aspartate-mediated pyrimidine nucleotide synthesis is essential for intracellular DNA homeostasis. ( B ) Heatmap from RNA-seq revealing the expression of DNA repair enzymes in L929 cells with indicated treatment. The fold-change of expression was normalized to the mock group ( n = 3 independent cultures). ( C ) Genome browser screenshots of END-seq on mitochondria from L929 cells with indicated treatment. The expanded view of the indicated region shows more detailed genomic features. ( D ) The proportion of END-seq reads in mitochondrial and nuclear chromosomal regions. ( E ) Representative immunofluorescence images of mitochondrial (TOM20, red) or dsDNA (green) in BJ-5ta cells treated with AOA in the absence or presence of 20 mM aspartate for 6 hours. Scale bars, 10 μm. Lower panel: quantification of cytosolic dsDNA in BJ-5ta cells with indicated treatment ( n = 39–51 fields per group from 3 biological replicates). ( F ) Representative immunofluorescence images of BJ-5ta cells treated with ddC (100 μM) for 72 hours, followed by 6 hours of AOA treatment in the absence or presence of 20 mM aspartate. ( G ) 2D–structured illumination microscopy imaging of mtDNA externalization under the indicated conditions. ( H ) Western blot detected α-tubulin (cytosol), TOM20 (OMM), PDH (Matrix), COX IV (IMM), and histone H3 (nuclei) to validate protocol from in L929 cells treated as indicated. wcl, whole cell lysate; pel, pellet; cyt, cytosolic fraction. ( I ) L929 cells were treated with AOA in the absence or presence of 20 mM aspartate followed by HT-DNA transfection, and then cells were harvested for qPCR analysis of mtDNA or nDNA levels in cytosolic fractions. Data are represented as means ± SEM. Representative data are shown from 2 or 3 independent experiments. Statistical analysis was performed by 1-way ANOVA followed by Tukey’s test ( E and I ). * P < 0.05; ** P < 0.01; *** P < 0.001; **** P < 0.0001. DSBs, double-strand breaks.
Article Snippet: Six- to 8-week-old C57BL/6J mice were purchased from Beijing Vital River Laboratory Animal Technology Co., Ltd, and age-matched Ifnar1 -KO C57BL/6J mice were obtained from Cyagen Biosciences (Suzhou) Inc. BJ-5ta and L929 cells were obtained from ATCC, while B16-F10 and MC38 cells were purchased from the National Collection of Authenticated Cell Cultures.
Techniques: RNA Sequencing, Expressing, Immunofluorescence, Microscopy, Imaging, Western Blot, Transfection