Cadmium and molybdenum co-exposure triggers autophagy via CYP450s/ROS pathway in duck renal tubular epithelial cells.

Cadmium (Cd) and excessive molybdenum (Mo) are detrimental to animals, but the combined nephrotoxic impacts of Cd and Mo on duck are still unclear. To evaluate the combined impacts of Cd and Mo on autophagy via Cytochrome P450s (CYP450s)/reactive oxygen species (ROS) pathway, duck renal tubular epithelial cells were treated with 3CdSO4·8H2O (4.0 μM Cd), (NH4)6Mo7O24·4H2O (500.0 μM Mo), butylated hydroxy anisole (BHA) (100.0 μM) and combination of Cd and Mo or Cd, Mo and BHA for 12 h, and combined cytotoxicity was investigated. The results indicated that Mo or/and Cd induced CYP1A1, CYP1B1, CYP2C9, CYP3A8 and CYP4B1 mRNA levels, decreased superoxide dismutase (SOD), catalase (CAT) activities and glutathione peroxidase (GSH-Px) content, and increased malondialdehyde (MDA) and hydrogen peroxide (H2O2) contents. Besides, Mo or/and Cd elevated the number of autophagosome and microtubule-associated protein light chain 3 (LC3) puncta, upregulated mRNA levels of Beclin-1, LC3A, LC3B, Atg5 and adenosine 5'-monophosphate (AMP)-activated protein kinase α1 (AMPKα-1), inhibited Dynein, p62 and mammalian target of rapamycin (mTOR) mRNA levels, increased Beclin-1 and LC3II/LC3I protein levels. Moreover, the changes of these factors in Mo and Cd co-treated groups were more apparent. Additionally, BHA could efficiently alleviate the changes of above these indicators co-induced by Mo and Cd. Overall, these results manifest Cd and Mo co-exposure may synergistically trigger autophagy via CYP450s/ROS pathway in duck renal tubular epithelial cells.

Zhang C ，Wang X ，Pi S ，Wei Z ，Wang C ，Yang F ，Li G ，Nie G ，Hu G ... -  《-》

Inhibition of autophagy aggravates molybdenum-induced mitochondrial dysfunction by aggravating oxidative stress in duck renal tubular epithelial cells.

Excessive molybdenum (Mo) has adverse effects on animals. To elucidate the effects of autophagy on Mo-induced nephrotoxicity, the duck renal tubular epithelial cells were cultured in medium in absence and presence of (NH4)6Mo7O24.4H2O (0, 480, 720, 960 μM Mo), 3-Methyladenine (3-MA) (2.5 μM), and the combination of Mo and 3-MA for 12 h. After 12 h exposure, the MDC staining, morphologic observation, LC3 puncta, cell viability, autophagy-related genes mRNA and proteins levels, lactate dehydrogenase (LDH) release, reactive oxygen species (ROS) level, antioxidant indices, mitochondrial membrane potential (MMP), mitochondrial mass, mitochondrial respiratory control ratio (RCR) and oxidative phosphorylation rate (OPR) were determined. The results showed that excessive Mo exposure significantly elevated the number of autophagosome and LC3 puncta, upregulated Beclin-1, Atg5, LC3A and LC3B mRNA levels, and LC3II/LC3I and Beclin-1 protein levels, decreased mTOR, p62 and Dynein mRNA levels and p62 protein level. Besides, co-treatment with Mo and 3-MA dramatically increased LDH release, ROS level, hydrogen peroxide (H2O2) and malondialdehyde (MDA) contents as well as cell dam age, reduced cell viability, the activities of glutathione peroxidase (GSH-Px), superoxide dismutase (SOD), catalase (CAT), MMP, mitochondrial mass, mitochondrial RCR and OPR compared to treatment with Mo alone. Taken together, these results suggest that excessive Mo exposure can induce autophagy in duck renal tubular epithelial cells, inhibition of autophagy aggravates Mo-induced mitochondrial dysfunction by regulating oxidative stress.

Zhuang J ，Nie G ，Hu R ，Wang C ，Xing C ，Li G ，Hu G ，Yang F ，Zhang C ... -  《-》

Nrf2 axis and endoplasmic reticulum stress mediated autophagy activation is involved in molybdenum and cadmium co-induced hepatotoxicity in ducks.

Excessive molybdenum (Mo) and cadmium (Cd) have toxic effects on animals. However, hepatotoxicity co-induced by Mo and Cd in ducks is still unclear. To evaluate the effects of Cd and Mo co-exposure on autophagy by nuclear factor erythroid 2-related factor 2 (Nrf2)-mediated antioxidant defense and endoplasmic reticulum stress (ERS) in duck livers, 40 healthy 7-day-old ducks were randomly assigned to 4 groups and fed diets containing different doses of Mo and/or Cd for 16 weeks, respectively. The results verified that Mo and/or Cd induced oxidative stress via decreasing glutathione peroxidase (GSH-Px), catalase (CAT), and total-superoxide dismutase (T-SOD) activities and increasing hydrogen peroxide (H2O2) and malondialdehyde (MDA) concentrations; inhibited Nrf2 axis by downregulating the pathway-related genes and proteins expression levels, and activated ERS through upregulating the protein kinase RNA-like endoplasmic reticulum kinase (PERK)/eukaryotic initiation factor 2a (eIF2a), inositol-requiring enzyme 1 (IRE1) and activating transcription factor 6 (ATF6) pathway-related genes and proteins expression levels, which triggered autophagy via increasing autophagosomes, light chain 3 (LC3) puncta, LC3A, LC3B, autophagy-related gene 5 (Atg5), Bcl-2-interacting protein (Beclin-1) mRNA levels and Beclin-1, microtubule-associated protein light chain 3 II/I (LC3II/LC3I) protein levels, decreasing Dynein, p62, mammalian target of rapamycin (mTOR) mRNA levels and p62 protein level. Additionally, the changes in Mo and Cd group were the most obvious. Briefly, our study reveals that autophagy induced by Mo and/or Cd may be associated with the activation of crosstalk between Nrf2-mediated antioxidant defense response and ERS in duck livers. Mo and Cd may aggravate toxic damage to the liver.

Wang X ，Hu R ，Wang C ，Wei Z ，Pi S ，Li Y ，Li G ，Yang F ，Zhang C ... -  《-》

Cadmium and molybdenum co-induce pyroptosis via ROS/PTEN/PI3K/AKT axis in duck renal tubular epithelial cells.

Cadmium (Cd) and excess molybdenum (Mo) are harmful to animals, but the combined nephrotoxic mechanism of Cd and Mo in duck remains poorly elucidated. To assess joint effects of Cd and Mo on pyroptosis via ROS/PTEN/PI3K/AKT axis in duck renal tubular epithelial cells, cells were cultured with 3CdSO4·8H2O (4.0 μM), (NH4)6Mo7O24·4H2O (500.0 μM), MCC950 (10.0 μM), BHA (100.0 μM) and combination of Cd and Mo or Cd, Mo and MCC950 or Cd, Mo and BHA for 12 h, and the joint cytotoxicity was explored. The results manifested that toxicity of non-equitoxic binary mixtures of Mo and Cd exhibited synergic interaction. Mo or/and Cd elevated ROS level, PTEN mRNA and protein levels, and decreased PI3K, AKT and p-AKT expression levels. Simultaneously, Mo or/and Cd upregulated ASC, NLRP3, NEK7, Caspase-1, GSDMA, GSDME, IL-18 and IL-1β mRNA levels and Caspase-1 p20, NLRP3, ASC, GSDMD protein levels, increased the percentage of pyroptotic cells, LDH, NO, IL-18 and IL-1β releases as well as relative conductivity. Moreover, NLRP3 inhibitor MCC950 and ROS scavenger BHA could ameliorate the above changed factors induced by Mo and Cd co-exposure. Collectively, our results reveal that combination of Mo and Cd synergistically cause oxidative stress and trigger pyroptosis via ROS/PTEN/PI3K/AKT axis in duck tubular epithelial cells.

Zhang C ，Lin T ，Nie G ，Hu R ，Pi S ，Wei Z ，Wang C ，Xing C ，Hu G ... -  《-》

Molybdenum and cadmium co-induce oxidative stress and apoptosis through mitochondria-mediated pathway in duck renal tubular epithelial cells.

High doses of molybdenum (Mo) and cadmium (Cd) cause adverse reactions on animals, but the joint toxic effects of Mo and Cd on duck renal tubular epithelial cells are not fully illustrated. To investigate the combined effects of Mo and Cd on oxidative stress and mitochondrial apoptosis in primary duck renal tubular epithelial cells, the cells were either treated with (NH4)6Mo7O24·4H2O (480, 960 μM Mo), 3CdSO4·8H2O (2.5, 5.0 μM Cd) or combination of Mo and Cd for 12 h, and then the joint cytotoxicity was evaluated. The results demonstrated that Mo or/and Cd exposure could induce release of intracellular lactate dehydrogenase, reactive oxygen species generation, acidification, increase levels of malondialdehyde and [Ca2+]i, decrease levels of glutathione, glutathione peroxidase, catalase, superoxide dismutase, total antioxidant capacity, Na+/K+-ATPase, Ca2+-ATPase, and mitochondrial membrane potential; upregulate mRNA levels of Caspase-3, Bak-1, Bax, and cytochrome C, inhibit Bcl-2 mRNA level, and induce cell apoptosis in a dose-dependent manner. Furthermore, the changes of these indicators in co-treated groups were more remarkable. The results indicated that exposure to Mo or/and Cd could induce oxidative stress and apoptosis via the mitochondrial pathway in duck renal tubular epithelial cells and the two metals may have a synergistic effect.

Wang C ，Nie G ，Yang F ，Chen J ，Zhuang Y ，Dai X ，Liao Z ，Yang Z ，Cao H ，Xing C ，Hu G ，Zhang C ... -  《-》