GCG and immune system disorder: The G-protein-coupled receptors GPR41 and GPR43 are important regulatory factors that regulate glucose and lipid metabolism and can be directly activated by SCFAs to induce the formation of glucagon-like peptide 1 (GLP-1) and gastrointestinal polypeptide YY (PYY), which inhibit cellular inflammation and related immune diseases (Brar and Kohn, 2019; Roy et al., 2020; Zhang et al., 2023).