MAPK9 and liver disorder: Indeed, in bone marrow transplant chimeric mice where Kupffer cells were being replaced with JNK1 and JNK2 knockout cells, JNK1 was found to be needed for the progression towards liver fibrosis through induction of chronic inflammation.[146] Putting the data together, JNK1 contributes significantly towards the pathological development of liver diseases and is therefore a potential therapeutic target.