Molecular cloning, characterization and expression analysis of PINK1 (Phosphatase and tensin homolog-induced putative kinase 1) and Parkin (parkin RBR E3 ubiquitin protein ligase) in grass carp (Ctenopharyngodon idellus).

Phosphatase and tensin homolog-induced putative kinase 1 (PINK1) and parkin RBR E3 ubiquitin protein ligase (Parkin) emerged as mediators of mitophagy and regulators of the immune response in mammals. However, their gene characterizations and roles remain poorly understood in fish. Herein, we identified and characterized pink1 and parkin genes and studied their involvement in immune responses to lipopolysaccharide (LPS) in Ctenopharyngodon idellus kidney (CIK) cells. Bioinformatic analysis found that PINK1 and Parkin were relatively conservative during evolution. In CIK cells, LPS significantly increased the mRNA expression of the transcription factor nf-κb and its downstream proinflammatory cytokines, such as tnfα, il-6 and il-1β, along with the activation of PINK1/Parkin-mediated mitophagy (P < 0.05). Furthermore, inhibition of mitophagy aggravated LPS-induced inflammation in CIK cells. Overall, our findings suggest that PINK1/Parkin-mediated mitophagy may play a protective role in LPS-induced inflammation in fish.