Fig. 1: Sites of intestinal heat shock proteins release and their kinetics and action.

a iTraQ-based analysis of proteins (n = 48) differentially expressed in the jejunal secretome in chow diet versus high-fat diet (n = 4 biologically independent animals). Downregulated proteins (n = 17) are colored in green while upregulated proteins (n = 31) are colored in orange. b Insulin-mediated glucose uptake of rat primary myocytes treated with HSP70 (15 ng/ml), GRP78 (3 ng/ml) alone or in combination with their respective mAbs (1 μg/ml). Rat myocytes were stimulated with 100 nM insulin for 10 min (n = 5 independent experiments). c, d Representative confocal microscopy images of FACS isolated rat enteroendocrine cells (c) stained for Claudin-4 (CLD4,red) and rat intestinal epithelial cells (d) stained for Integrin-β4 (ITB4,green) (n = 5 independent experiments). e HSP70 and GRP78 concentration in the culture medium of rat intestinal epithelial and enteroendocrine cells untreated or stimulated with 0.5 mM palmitic acid (n = 5 independent experiments). f Jejunal expression of key proteins involved in Unfolded Protein Response (UPR) in rats fed either chow diet (CD) or high-fat diet (HFD) (n = 5 biologically independent animals). g Expression of UPR proteins in rat intestinal epithelial cells untreated or stimulated with 0.5 mM palmitic acid (n = 5 independent experiments). h, i Time courses and fitting curves of recombinant (black circles) and native (red squares) HSP70 (h) and GRP78 (i) during and after a 2 h infusion of 2.5 ng/h of recombinant proteins and after an intragastric load of palm oil (n = 4 biologically independent animals). Magnification ×60. Scale bar: 50 μm Data are presented as mean value ± SEM. Statistical significances were calculated by unpaired two-tailed t-test and one-way Anova with Bonferroni’s correction for multiple comparisons, where appropriate. Source data are provided as a Source Data file.