Fig. 8

Monocarboxylate transporter 1 (MCT1) is the essential transport protein involved in propionate-induced energy expenditure. HFD-fed mice were treated with propionate and/or MCT inhibitor intervention for 4 weeks. a Schematic diagram of propionate supplementation and MCT inhibitor intervention. b Body weight. c Daily food intake. d, e Core temperature against room temperature (d) and cold stress (e). f Relative mRNA expression of thermogenic genes in iWAT. g Representative UCP1 staining of iWAT sections, scale bar: 50 μm. h Protein expression of MCT1 and MCT4 in iWAT. The mice were fed a HFD for 10 weeks and then treated with L. reuteri + CQA twice per week for 3 weeks after AAV injection. i Experimental design and iWAT AAV injection. j Relative mRNA level of Mct1 in iWAT injected with AAV-shMct1 or AAV-Scramble. k Body weight. l Core temperature. m Relative mRNA expression of thermogenic genes in iWAT. n Representative UCP1 staining of iWAT sections, scale bar: 50 μm. o Proposed model for the anti-obesity effects of caffeoylquinic acid (CQA) via L. reuteri-propionate-beige fat axis. b–h n = 9/group. j–n n = 5/group. Data are presented as mean ± SD. *p < 0.05; **p < 0.01; and ***p < 0.001. ns means not statistically significant. “RQ” means L. reuteri + CQA co-treatment; “PA” means propionate treatment; “i” means treating combined with MCT inhibitor 7ACC1