NIK/MAP3K14 in hepatocytes orchestrates NASH to hepatocellular carcinoma progression via JAK2/STAT5 inhibition

Nonalcoholic fatty liver disease (NAFLD) ranges from steatosis to nonalcoholic steatohepatitis (NASH), that often progresses to hepatocellular carcinoma (HCC) through a largely undefined mechanism. NASH and HCC both depend on inflammatory signaling whose master regulator is the NFκB transcription factor family, activated by canonical and non-canonical pathways. Here, we investigated non-canonical NFκB-inducing kinase (NIK/MAP3K14) in metabolic NASH, NASH to HCC transition as well as in DEN-induced HCC. We revealed that hepatocyte-specific NIK deficiency (NIKLKO) ameliorated metabolic NASH complications and reduced hepatocarcinogenesis however, independent of its role in NFB pathway. Instead, hepatic NIK attenuated hepatoprotective JAK2/STAT5 signaling that is a prerequisite for NASH and NASH to HCC progression in mice and humans. Our data suggest NIK-mediated inhibitory JAK2 phosphorylation at serine 633 that might be amenable for future therapeutic interventions in patients. Five non-tumor and five tumor biopsy samples were obtained and their transcriptional profiles compared.