A BAFF/APRIL axis regulates obesogenic diet-driven weight gain

Fig. 1. BAFF axis regulates obesity development. a Weight gain of WT or RP105−/− mice fed a high-fat diet (HFD) for 24 weeks. b–d WT, RP105−/− or RP105−/−/BAFF−/− mice were fed HFD for 16 weeks. b Weight gain. c Fasting glucose. d Glucose tolerance test (GTT). e Area under the curve (AUC). f Low-fat chow diet fed WT, RP105−/−, or RP105−/−/BAFF−/− were monitored in TSE Phenomaster systems for 3 days. Combined energy expenditure. g–h WT, RP105−/−, μMT or BAFF-Tg mice fed HFD for 15 weeks. g Systemic BAFF concentration quantified by ELISA. h Weight gain. i–m WT or BAFF-Tg mice fed HFD for 20 weeks. i Fasting glucose at 20 weeks. j GTT at 12 weeks. k AUC. l Liver triglycerides quantified by colorimetric assay at harvest. m Systemic alanine transaminase (ALT) at harvest. a Representative of six independent experiments, n = 4–8/condition. b–e Representative of three independent experiments, n = 4–7/condition. f A single experiment, n = 5–6/condition. g–h Representative of three independent experiments, n = 3–4/condition. i–m Representative of three independent experiments, n = 3–6/condition. a–m For bar and line graphs, data represents mean±SEM. a–b, d–e, j–k Area under the curve. N.S = not…

Fig. 2. BAFF modifies white adipose lipid handling. a White adipocytes stimulated in the presence or absence of recombinant BAFF (rBAFF; 500 ng/ml) and subjected to RNA-seq analysis. Ontology pathways and heat map of selected associated genes. b eWAT mRNA expression quantified by qPCR of indicated lipolysis genes in WT, RP105−/− or BAFF-Tg mice after 20 weeks on a HFD. c–d White adipocytes treated with saline (NS), norepinephrine (1 µM), or rBAFF (500 ng/ml) for 24 hours. c Free glycerol. % increase relative to WT NS. d mRNA expression of indicated lipolysis genes. e CD-fed WT mice were treated i.p. with rBAFF (2 μg/mouse) every other day for 1 week. eWAT mRNA expression of indicated lipolysis genes. f Primary white adipocytes from WT mice were treated with saline (NS), norepinephrine (NE; 1 µM), or rBAFF (b 500 ng/ml) for 12 hours. Protein expression of hormone-sensitive lipase (HSL), phosphorlayted HSL (p-HSL), and α-tubulin loading control by western blot. g Free glycerol in supernatants of WT, BAFF-R−/−, TACI−/−, or BCMA−/− adipocytes treated with saline (NS) or rBAFF (500 ng/ml). % increase relative to WT NS. a A single experiment, n = 2/condition. b Representative of three…

Fig. 3. BAFF modifies brown adipose adaptive thermogenesis. a–b WT, RP105−/−, or BAFF-Tg mice were fed HFD for 20 weeks. a BAT Ucp1 mRNA expression quantified by qPCR. b BAT mitochondria oxygen consumption. c–d Brown adipocytes were treated with saline (NS) or rBAFF (500 ng/ml) for 6 hours. c Ucp1 mRNA expression quantified by qPCR, relative expression to NS. d Oxygen consumption rate (OCR). e Oxygen consumption of WT mice treated with saline (NS) or rBAFF (2 μg/mouse) for 24 hours prior to norepinephrine (NE; 1 mg/kg) challenge. f–g Obese WT mice treated with rBAFF (2 μg/mouse) every other day for 1 week and monitored in TSE Phenomaster. f Monitoring of energy expenditure over 5 days. g Bar graph of combined energy expenditure. a–b Representative of n = 3–6/condition. c–d Representative of three independent experiments, n = 4–5/condition. e Representative of two independent experiments, n = 3–4/condition. f–g A single experiment, n = 3–5/condition. a–g For bar and line graphs, data represents mean±SEM. a–d Unpaired two-tailed Student’s t test. e Area under the curve. f–g analysis of covariance (ANCOVA) with body weight as covariate. *p < 0.05, ***p < 0.001. Source data are provided as a…

Fig. 4. APRIL modifies white adipose lipolysis and brown adipose adaptive thermogenesis. a Weight gain of WT or BAFF−/− mice fed HFD for 20 weeks. b Systemic APRIL concentration in WT or BAFF−/− mice quantified by ELISA. c–d White adipocytes stimulated in the presence or absence of rBAFF (500 ng/ml), rAPRIL (500 ng/ml), or saline and subjected to RNA-seq analysis. c Venn diagram analysis of genes modified by BAFF and APRIL. d Ontology pathways and heat map of associated overlapped genes. e qPCR quantified mRNA expression of indicated lipolysis genes in white adipocytes treated with saline (NS) or rAPRIL (500 ng/ml) for 24 hours. f Lean WT mice treated with rAPRIL (2 μg/mouse) every other day for 2 weeks. eWAT mRNA expression of indicated lipolysis genes quantified by qPCR, relative expression to saline-treated controls. g Primary white adipocytes from WT mice were treated with saline (NS), norepinephrine (NE; 1 µM) or rAPRIL (a; 500 ng/ml) for 12 hours. Protein expression of hormone-sensitive lipase (HSL), phosphorlayted HSL (p-HSL), and α-tubulin loading control by western blot. h Free glycerol in supernatants, quantified by colorimetric assay, of WT, BAFF-R−/−, TACI−/−, or BCMA−/−…

Fig. 5. APRIL-deficient mice are protected from obesity development. a–j WT and APRIL−/− mice were fed HFD for 20 weeks. a Systemic BAFF concentration quantified by ELISA. b Weight gain. c Tissue weight distribution as indicated at time of harvest. d Food Intake. e Combined energy expenditure at 16 weeks of HFD analyzed by TSE Phenomaster system. f Fasting glucose at 20 weeks of HFD. g GTT at 14 weeks of HFD. h AUC. i Fasting insulin at 20 weeks of HFD. j Systemic ALT at 20 weeks of HFD. k Weight gain of WT, BAFF−/−, APRIL−/−, or BAFF−/−/APRIL−/− mice fed HFD for 20 weeks. a–j Representative of three independent experiments, n = 6-7/condition. a–j For bar and line graphs, data represent mean ± SEM. a, c–f, i–j Unpaired two-tailed Student’s t test. *p < 0.05, **p < 0.01, ***p < 0.001. b, g–h Area under the curve. **p < 0.01, ****p < 0.0001. Source data are provided as a Source data file.

Fig. 6. Lack of BAFF and APRIL exacerbates diet-induced weight gain. a Weight gain of WT, BAFF−/−, APRIL−/−, and BAFF−/−/APRIL−/− mice fed HFD for 20 weeks. b–f WT and BAFF−/−/APRIL−/− mice fed HFD for 20 weeks. b Tissue weight distribution as indicated at time of harvest. c Fasting glucose at 14 weeks of HFD. d GTT at 14 weeks of HFD. e AUC. f Systemic ALT at time of harvest. a A single experiment, n = 3–6/condition. b–f A single experiment, n = 3–4/condition. a–f For bar and line graphs, data represent mean±SEM. a, d Area under the curve. b–c, e–f Unpaired two-tailed Student’s t test. a–e *p < 0.05, ****p < 0.0001. Source data are provided as a Source data file.

Fig. 7. Effect of BAFF and APRIL axis is conserved in human adipocytes. a–b Human primary adipocytes isolated from persons undergoing bariatric surgery. Adipocytes were treated with saline (NS), rBAFF (500 ng/ml), or rAPRIL (500 ng/ml) for 24 hours as indicated. a Supernatant free glycerol quantified by colorimetric assay. b LIPE mRNA expression quantified by qPCR, normalized to NS. c PNPLA2 mRNA expression quantified by qPCR, normalized to NS. d BAFF and e APRIL systemic concentration in lean or obese persons quantified by multiplex. f BAFF and g APRIL systemic concentration correlation with BMI. h BAFF and i APRIL systemic concentration correlation with decrease in BMI 1-year after bariatric surgery. a–c Representative persons, n = 9–10/condition. d–g Representative patients, n = 4 lean and n = 30 obese. h–i Data combined, n = 22 persons undergoing bariatric surgery. a–c For bar and line graphs, data represents mean±SEM. d–e For box plots, the midline represents the mean, boxes represent the interquartile range and whiskers show the full range of values. a–e Unpaired two-tailed Student’s t test. a, c, d *p < 0.05, ****p < 0.0001. f–i Linear regression. Source data are provided as a…

Fig. 8. BAFF and APRIL axis regulates adipose tissue/adipocyte function and body weight gain. A proposed model of the impact of the BAFF/APRIL axis on white and brown AT/adipocyte lipid handling. BAFF/APRIL regulation of AT/adipocytes function is associated with protection from DIO in mice. The effect of this axis positively correlates with greater loss of body weight in bariatric patients.