Fig. 3: Characterization of organ-specific metabolic activity using MSITracer.
From: Spatial isotope deep tracing deciphers inter-tissue metabolic crosstalk
a AFADESI-MS images of glucose M0, M6, and M3 following U-13C glucose infusion. The heatmap shows normalized labeling across various organs. Signal intensity is shown in ion counts. BAT, brown adipose tissue; Bra, brain; Kid, kidney; Liv, liver; Lun, lung; Pan, pancreas. b AFADESI-MS images of glutamine M0, M5, and M2 following U-13C glutamine infusion. The heatmap shows normalized labeling across various organs. Signal intensity is shown in ion counts. c Representative AFADESI-MS images of organ-specific labeled metabolites following U-13C glucose infusion. The organs of interest are delineated with dashed lines in different colors. Signal intensity is shown in ion counts. NAA, N-acetyl aspartate. d Time-course mean enrichment of lactate and succinate in the brain, lung, heart, kidney and liver. e Exponential fitting of the unlabeled fraction of lactate and succinate in the five organs. Data are presented as mean ± SD (n = 3 biological replicates). Source data are provided as a Source Data file. f Notable spatial distribution differences among the native aspartate and corresponding isotopologues following U-13C-glutamine infusion. Signal intensity is shown in ion counts. g Schematic diagram of 13C-atom translations from U-13C-glutamine. Colored circles denote 13C carbons, while white circles represent 12C carbons. Red circles indicate labeling in the first turn of the TCA cycle, whereas blue circles indicate labeling in the second turn of the TCA cycle. h Illustration of the glutamine-glucose metabolic coordination between kidney, liver and brain. Created in BioRender. Li, X. (https://BioRender.com/gc0ge5m).
