Comparative mitochondrial proteomic: PGAM5-mediated necroptosis through excessive mitophagy in sheep livers under molybdenum and cadmium co-exposure

Abstract

Accumulation of excessive molybdenum (Mo) and cadmium (Cd) in the environment poses detrimental effects on organisms. The precise mechanisms of hepatotoxicity that are involved with mitochondria, resulting from the co-exposure to Mo and Cd, remain poorly understood and elusive. To fill the gap, a total of 24 sheep were stratified into two groups: control group and Mo + Cd group (45 mg Mo·kg⁻¹·B.W. and 1 mg Cd·kg⁻¹·B.W.). Results showed that exposure to Mo and Cd adversely co-induced the liver function related biochemical marker alterations in serum, histopathological abnormalities, mitochondrial ultrastructure damage and oxidative stress in the livers of sheep. Sequencing results from isolated mitochondria indicated that a total of approximately 4788 mitochondria-localized proteins were identified, of which 360 exhibited significant differential expression. GO and KEGG database analysis demonstrated excessive Mo and Cd primarily induced hepatotoxicity by affecting mitochondria-mediated oxidation-reduction processes, single-organism metabolic processes, and enhancing the TNF signaling pathway. Mo and Cd co-exposure increased the levels of mitophagy- and necroptosis- related factors regulated by PGAM5 in the livers. Consistently, our findings highlight the co-exposure of Mo and Cd induced necroptosis triggered by PGAM5-mediated mitophagy, which offers valuable insights into the toxicological mechanisms underlying the combined effects of Mo and Cd.