Fig. 1: Cysteine deficiency induces weight loss.
From: Cysteine depletion triggers adipose tissue thermogenesis and weight loss
a, Principal-component analysis of the metabolome of subcutaneous adipose depots (SFAT) of healthy individuals at baseline and after 12 months of CR (n = 14). b, Metabolite set enrichment analysis shows that compared to baseline, 1 year of CR in humans activates TSP, with increased cysteine and taurine metabolism. c, Schematic summary of TSP and metabolites from baseline to 1 year CR, measured in human SFAT. Blue lines indicate unchanged metabolites, green and red arrows indicate significantly increased or decreased metabolites or genes respectively, via paired t-test (P < 0.05). SAM, S-adenosyl methionine. d,e, Normalized expression of changes in CTH and BHMT in human SFAT at baseline, and after 12 and 24 months of CR. Adjusted P values were calculated in the differential gene expression analysis in a separate cohort from metabolome analyses in the CALERIE-II trial1 (n = 8). B, baseline. f,g, Change in metabolites in human SFAT at baseline and 12 months of CR. Significance was calculated using paired t-tests (n = 14). AU, arbitrary unit. h, Mouse model used to achieve cysteine deficiency utilizing Cth−/− mice fed a CysF diet. i, Male Cth+/+ and Cth−/− mice were fed control (CTRL) or CysF diets for 6 days (n = 5 Cth+/+ CTRL, n = 12 Cth+/+ CysF, n = 8 Cth−/− CTRL, n = 17 Cth−/− CysF; three experiments pooled). Per cent body weight represented over 6 days of diet. j, Cth−/− mice were fed purified control diet (black line) or a diet containing 75% cysteine (green line) alternately switched to CysF diet (green line with red dots n = 6 per group). k, Box plots of metabolites involved in TSP in the serum of Cth−/− mice fed CTRL or CysF diet for 6 days (n = 4 Cth−/− CTRL, n = 5 Cth−/− CysF). l, Schematic summary of changes in the metabolites in the serum of Cth−/− mice fed CTRL or CysF diet for 6 days. Blue lines represent measured, but unchanged metabolites, red and green arrows indicate significantly decreased or increased metabolites, respectively (P < 0.05). See Supplementary Table 1 for the full list of metabolites. m, Total GSH content in subcutaneous (SFAT), brown (BAT) adipose depots and liver of Cth−/− mice fed with CTRL or CysF diet for 5 days (n = 7 per group), determined by colorimetric assay. n, Box plots of GSSG and threonine quantification in the SFAT of Cth−/− mice fed CTRL or CysF diet for 6 days (n = 6 per group). o,p, RNA-seq based expression of Gclc, Gss (o) and Bola3 (p) in the SFAT of Cth−/− mice fed with CTRL or CysF for 6 days. FPKM, fragments per kilobase of exon model per million mapped fragments. q, Coenzyme A (CoA) content in SFAT, BAT and liver samples of Cth−/− mice fed with CTRL or CysF diet for 5 days, determined by fluorometric assay (n = 7 per group, ND, not detectable). r, Analysis of EPR spectra of POBN-lipid radical adducts measured in Folch extracts of visceral adipose depot (VFAT), SFAT and BAT tissues from Cth−/− mice fed with CTRL or CysF diet for 5 days, normalized to 100 mg (ND, not detectable; n = 5–6 per group). s, Aconitase activity determined in SFAT, VFAT and BAT tissues from Cth−/− mice fed with CTRL or CysF diet for 5 days (n = 6 CTRL and 7 CysF). Data are represented as mean ± s.e.m. Box plots represent median value and extend to the 25th and 75th percentiles. Whiskers are plotted down to the minimum and up to the maximum value. Unless mentioned, differences were determined with unpaired two-tailed t-tests. Panels c, h and l created with BioRender.com.
