Diclofenac Disrupts the Circadian Clock and through Complex Cross-Talks Aggravates Immune-Mediated Liver Injury—A Repeated Dose Study in Minipigs for 28 Days

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Abstract
Diclofenac effectively reduces pain and inflammation; however, its use is associated with hepato- and nephrotoxicity. To delineate mechanisms of injury, we investigated a clinically relevant (3 mg/kg) and high-dose (15 mg/kg) in minipigs for 4 weeks. Initially, serum biochemistries and blood-smears indicated an inflammatory response but returned to normal after 4 weeks of treatment. Notwithstanding, histopathology revealed drug-induced hepatitis, marked glycogen depletion, necrosis and steatosis. Strikingly, the genomic study revealed diclofenac to desynchronize the liver clock with manifest inductions of its components CLOCK, NPAS2 and BMAL1. The > 4-fold induced CRY1 expression underscored an activated core-loop, and the dose dependent > 60% reduction in PER2mRNA repressed the negative feedback loop; however, it exacerbated hepatotoxicity. Bioinformatics enabled the construction of gene-regulatory networks, and we linked the disruption of the liver-clock to impaired glycogenesis, lipid metabolism and the control of immune responses, as shown by the 3-, 6- and 8-fold induced expression of pro-inflammatory CXCL2, lysozyme and ß-defensin. Additionally, diclofenac treatment caused adrenocortical hypertrophy and thymic atrophy, and we evidenced induced glucocorticoid receptor (GR) activity by immunohistochemistry. Given that REV-ERB connects the circadian clock with hepatic GR, its > 80% repression alleviated immune responses as manifested by repressed expressions of CXCL9(90%), CCL8(60%) and RSAD2(70%). Together, we propose a circuitry, whereby diclofenac desynchronizes the liver clock in the control of the hepatic metabolism and immune response.
Funding Information
  • German Federal Ministry of Education and Research (BMBF) (031 6154, COST CA17112, 01DR14013, NRF-2016M3A9C4953144, NRF-2014M3A7B6020163)
  • Prospective European Drug-Induced Liver Injury Network (031 6154, COST CA17112, 01DR14013, NRF-2016M3A9C4953144, NRF-2014M3A7B6020163)
  • Division of Toxicology, Korea Institute of Toxicology (KIT) (031 6154, COST CA17112, 01DR14013, NRF-2016M3A9C4953144, NRF-2014M3A7B6020163)
  • Ministry of Science, ICT and Future Planning (031 6154, COST CA17112, 01DR14013, NRF-2016M3A9C4953144, NRF-2014M3A7B6020163)

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