When the microtissues were treated with free fatty acids (FFAs) including Oleic acid (6.6×10−4M) and Palmitic acid (3.3×10−4M), they displayed the key features of NAFLD, including similar pattern of transcripts for genes involved in lipid metabolism, inflammation, insulin-resistance, and fibrosis, as well as pro-inflammatory and pro-fibrotic cytokines' secretions and intracellular lipid accumulation. The gene discussed is INS; the disease is metabolic dysfunction-associated steatotic liver disease.