CTSS and metabolic dysfunction-associated steatotic liver disease: STRING PPI networks were also used to identify key markers of specific immune cells, where hub genes upregulated in the liver of NAFLD mice included CD68 and CTSS in macrophages and leukocyte markers PTPRC and ITGAX, suggesting that cell adhesion processes play an important role in NAFLD within the context of the pathogenic immune response [102].