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. Author manuscript; available in PMC: 2023 Sep 13.
Published in final edited form as: Nat Metab. 2023 Mar 13;5(3):414–430. doi: 10.1038/s42255-023-00761-7

Figure 1. Integrated metabolomics and transcriptomics data analysis of human kidney samples.

Figure 1.

(A) Total of 50 human kidney samples were collected for metabolomics analysis; including healthy controls (n=25) and patients with kidney disease (n=25).

(B) Volcano plot of metabolites showing significant changes in human diseased kidneys. x-axis: log2 fold change (log2FC). Y-axis: -log10(p-value). Color indicates metabolites significantly higher (red) or lower (blue) in human diseased kidneys. Welch’s two-sided t-test was used to calculate p-value.

(C) Metabolic pathways showing significant changes in diseased kidneys. The dot color indicates the level of significance, the dot size indicates pathway impact. p-value was calculated from the enrichment analysis in Metaboanalyst.

(D) The simplified NAD salvage pathway. Blue indicates metabolites significantly lower in human diseased kidneys.

(E) The levels of NAD+, NMN, NR, and NAM in human kidneys (Healthy control n=25. Kidney disease n=25). * p<0.05. N.S. not significant. Data are presented as mean ± s.e.m. and were analyzed using Welch’s two-sided t-test.

(F) The bulk RNA-seq of same human kidney samples used for metabolomic studies.

(G) Gene ontology analysis of cellular composition of genes significantly correlating with kidney NAD+ levels. The dot color and size indicate significance and gene counts, respectively.

(H) The correlation between kidney NAD+ levels (x-axis) and relative genes expression (y-axis) encoding mitochondrial proteins. P-value was calculated using Pearson’s correlation.