Figure 6.

Effect of PTP1B deficiency on GLP-1 release by the gut under pro-inflammatory stimuli. A) GLP-1 serum levels from C57BL/6 J mice injected with LPS (2 mg/kg body weight) as described in Materials and Methods. Black dots represent control animals and gray dots correspond to animals under an LPS acute pro-inflammatory stimulus. n = 4–7 mice per experimental group. ∗p<0.05 PTP1B WT vs PTP1B WT LPS. B) Upper panel represents GLP-1 release from colonic organoids stimulated with pCM-LPS compared with organoids treated with pCM-C and DMEM-2%FBS. n = 2 independent experiments performed in triplicate. ^∗∗ p< 0.01 DMEM vs CM-LPS. Lower panel shows colonic organoids images used in this experiment. Upper panel shows a colonic organoid with budding crypt-like domains. Bottom panel shows an organoid with mature EEC L cells. Both images correspond to the same organoid, left image under light microscopy, right image under fluorescence microscopy. L cells (yellow fluorescence YFP) are shown in the right image. C) GLP-1 levels measured in the culture media from colonic crypts cultured under pro-inflammatory conditions. Data are expressed as fold change referred to control medium (DMEM alone). n = 3 independent experiments performed in quadruplicate. ^∗∗p < 0.01; ^∗∗∗p < 0.001 data referred to basal conditions; ^###p < 0.001 referred to pCM-LPS. D) GLP-1 serum levels measured in animals under chow or MCD diet during 4 weeks. n = 5–7 mice per experimental group. ^∗∗∗p < 0.001 PTP1B WT chow vs PTP1B WT MCD; ⁺⁺p < 0.01 PTP1B WT chow vs PTP1B KO chow. E) Gcg mRNA levels (encoding proglucagon) are shown as fold difference referred to the control PTP1B WT fed a chow diet. White dots correspond to mice fed a chow diet and black dots to mice fed a MCD diet during 4 weeks. All data are expressed as mean ± SEM. n = 5–8 animals per experimental group. ^∗∗∗p < 0.001 PTP1B WT chow vs PTP1B WT MCD ; ^###p < 0.001 PTP1B KO chow vs PTP1B KO MCD.