Extended Data Fig. 6: No evidence of GLP-1 receptor expression in mouse and human liver.
a, Assessment of GLP-1 receptor protein expression in mouse tissue samples by immunohistochemistry. Representative photomicrographs of sections of positive control tissues from C57Bl/6 normal mouse (pancreas, stomach, duodenum and kidney) all showed immunoreactive cell populations. Samples of normal liver (chow; n = 1) and livers from DIO-MASH (n = 4) and CDA-HFD mice (n = 4) are all devoid of GLP-1 receptor immunoreactivity. Scale bars, 50 µm (control tissues and bottom images of liver) or 250 µm (top images of liver). b, Assessment of GLP-1 receptor mRNA and protein expression in human liver by RNAscope in situ hybridization (top row) and immunohistochemistry (bottom row) on human tissue samples. Representative photomicrographs of sections of normal-range liver biopsies (n = 6) and liver biopsies from individuals with MASH and mild fibrosis (n = 7), moderate to severe fibrosis (n = 6) or cirrhosis (n = 7). Normal-range human pancreas sample served as a positive control for GLP-1 receptor expression (left). Scale bars, 50 µm. CDA-HFD, choline-deficient L-amino acid-defined high-fat diet; DIO, diet-induced obesity; GLP-1, glucagon-like peptide-1; MASH, metabolic dysfunction-associated steatohepatitis.
