INS and metabolic dysfunction-associated steatotic liver disease: Based on DNA methylation analysis, they found that the ApoB gene promoter region presents increased methylation of CpG dinucleotides.170 Increased dipeptidyl peptidase 4 (DPP4) expression in the liver aggravates the development of NAFLD by autocrine and paracrine effects on hepatic insulin signalling and decreasing the levels of GLP-1.171 DNA methylation is also involved in DPP4-induced NAFLD.