Palmitic acid induced the onset of lipotoxicity in a HepaSH-on-chip model with raised of H2O2 and IL-6, and altered p38/MAPK & JAK/STAT pathways.

Hepatic inflammation induced by lipotoxicity is a key event in the progression of liver steatosis to non-alcoholic steatohepatitis (NASH). To characterize this process, we investigated the response of HepaSH cells-a novel mature human hepatocyte derived from chimeric mice-to a weak but chronic palmitic acid (PA) exposure, a prevalent dietary fatty acid. To mimic the hepatic microphysiological environment, cells were cultured using organ-on-chip technology and exposed to PA for two weeks. Functional assays revealed no changes in glucose or lactate metabolism. Likewise, PA exposure did not alter albumin secretion, TGF-β1 or TNF-α production, bile acid synthesis, or CYP450 biotransformation activity. Furthermore, there was no lipid accumulation or change in triglyceride production. However, PA-treated cells cleared the palmitic acid and increased the levels of reactive oxygen species (H₂O₂) and interleukin-6 (IL-6) compared to controls. mRNA analysis concurrently revealed perturbations in transcriptional regulators and genes associated with lipid metabolism, NF-KB, inflammation, and mitochondrial functions. Addtional RT-qPCR confirmed the activation of the JNK1/MAPK8 gene in p38/MAPK and JAK2 in the JAK/STAT/IL-6 pathways in response to PA. We believed that our findings using an advanced mature human hepatic on-chip model would help to provide insight of the early stages of PA-induced lipotoxicity in hepatocytes.