Lactate utilization in Lace1 knockout mice promotes browning of inguinal white adipose tissue

Figures

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  Fig. 1. Lace1 is increased in iWAT by browning stimulation. a Transcriptomic analysis of genes upregulated in iWAT from 7-week-old male C57BL/6N mice subjected to CL challenge. b LACE1 protein expression in whole tissue of 7-week-old male C57BL/6N mice, n = 4. c Lace1 mRNA expression in whole tissue of 7-week-old male C57BL/6N mice, n = 4. d LACE1 and UCP1 protein expression in iWAT upon CL challenge; n = 5 for all groups. e Lace1 mRNA expression in iWAT upon CL challenge. Saline; n = 5, CL; n = 4. f Thermogenesis-related gene expression in iWAT upon CL challenge. Saline; n = 5, CL; n = 4. g LACE1 and UCP1 protein expression in iWAT upon cold exposure; n = 5 for all groups. h Lace1 mRNA expression in iWAT upon cold exposure; n = 5 for all groups. i Thermogenesis-related gene expression in iWAT upon cold exposure; n = 5 for all groups. j Correlation between Lace1 and Ucp1 mRNA levels under CL challenge. Saline; n = 5, CL; n = 4. k Correlation between Lace1 and Ucp1 mRNA levels upon cold exposure; n = 5 for all groups. All experiments were performed after intervention. The values are presented as the means ± SEMs. Significance was calculated via an unpaired two-tailed Student’s t-test. *p…

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  Fig. 2. Lace1 deficiency increases browning of iWAT following CL injection. a Scheme of the CL challenge once a day for 3 days. b LACE1 protein expression in iWAT of the Lace1 KO mice upon CL challenge; n = 3 for all groups. c Lace1 mRNA expression in iWAT of the Lace1 KO mice upon CL challenge. WT-saline; n = 5, KO-saline; n = 5, WT-CL; n = 5, KO-CL; n = 5. d Representative H&E staining of iWAT from the Lace1 KO mice upon CL challenge (scale bar = 50 μm); n = 3 per group. e UCP1 immunohistochemical staining of iWAT from the Lace1 KO mice upon CL challenge (scale bar = 50 μm); n = 3 per group. f Thermogenesis-related gene expression in iWAT of the Lace1 KO mice upon CL challenge. WT-saline; n = 5, KO-saline; n = 4, WT-CL; n = 6, KO-CL; n = 6–8. g, h Whole-body oxygen consumption rate (VO2) and heat generation in the Lace1 KO mice during CL challenge for 3 days; n = 5 for all groups. All experiments were performed after intervention. The values are presented as the means ± SEMs. Significance was calculated via an unpaired two-tailed Student’s t-test. *p < 0.05, **p < 0.01, ***p < 0.001.

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  Fig. 3. Lace1 deficiency increases browning of iWAT following cold exposure. a Scheme of cold exposure for 7 days. b LACE1 protein expression in iWAT of the Lace1 KO mice upon cold exposure; n = 3 for all groups. c Lace1 mRNA expression in iWAT of the Lace1 KO mice upon cold exposure; n = 5 for all groups. d Representative H&E staining of iWAT from the Lace1 KO mice upon cold exposure (scale bar = 50 μm); n = 3 for all groups. e UCP1 immunohistochemical staining of iWAT from the Lace1 KO mice upon cold exposure (scale bar = 50 μm); n = 3 for all groups. f Thermogenesis-related gene expression in iWAT of the Lace1 KO mice upon cold exposure; n = 7 for all groups. g, h Whole-body oxygen consumption rate (VO2) and heat generation in the Lace1 KO mice during cold exposure for 7 days; n = 5 for all groups. i Rectal temperature during cold exposure in the Lace1 KO mice; n = 8 for all groups. All experiments were performed after intervention. The values are presented as the means ± SEMs. Significance was calculated via an unpaired two-tailed Student’s t-test. *p < 0.05, **p < 0.01, ***p < 0.001.

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  Fig. 4. Lace1 deficiency promotes browning in CL-induced iWAT via lactate uptake and utilization. a Top 20 upregulated differentially expressed genes (DEGs) in iWAT from the Lace1 KO mice compared with those in iWAT from the WT mice subjected to CL challenge. b Circulating lactate levels in the Lace1 KO mice upon CL challenge. WT-saline; n = 4, KO-saline; n = 5, WT-CL; n = 6, KO-CL; n = 8. c Mct1 mRNA levels in whole tissues from the Lace1 KO mice upon CL challenge; n = 4 for all groups. d MCT1 protein levels in the iWAT of the Lace1 KO mice subjected to CL challenge; n = 3 for all groups. e Mct1 and Mct4 mRNA expression in iWAT of the Lace1 KO mice under CL challenge. WT-saline; n = 7, KO-saline; n = 6, WT-CL; n = 6, KO-CL; n = 6. f Ldhb and Ldha mRNA expression in the iWAT of the Lace1 KO mice subjected to CL challenge; n = 5 for all groups. WT-saline. Ldhb/Ldha expression ratio in iWAT of the Lace1 KO mice under CL challenge. The values were calculated from the mRNA expression values; n = 5 for all groups. WT-saline; n = 6, KO-saline; n = 6, WT-CL; n = 6, KO-CL; n = 7. g Scheme of Lace1 knockdown (KD) and isoproterenol treatment of fully differentiated brown adipocytes from the iBPA…

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  Fig. 5. Lace1 deficiency promotes lactate efflux in CL-induced hearts. a Scheme of CL challenge once a day for 3 days and the mechanisms of lactate release via phosphorylation of pyruvate dehydrogenase and the mechanisms of lactate release via phosphorylation of pyruvate dehydrogenase in the heart. b Mct4 mRNA levels in the whole tissue of the Lace1 KO mice upon CL challenge; n = 4 for all groups. c, d MCT4 protein levels in the hearts of the Lace1 KO mice subjected to CL challenge; n = 3 for all groups. d–f Lace1, phospho-PDH (Ser293) and total PDH protein levels in the hearts of the Lace1 KO mice subjected to CL challenge; n = 3 for all groups. g Ldha and Ldhb mRNA expression in the hearts of the Lace1 KO mice subjected to CL challenge; n = 5 for all groups.

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  Fig. 6. A proposed model of lactate-induced browning in Lace1 KO mice. Scheme of lactate-induced browning of iWAT in Lace1 KO mice.