Effect of copper chloride exposure on the membrane potential and cytosolic free calcium in primary cultured chicken hepatocytes

Antiparasitic effect of copper alloy mesh on tomont stage of Cryptocaryon irritans in aquaculture

Copper alloy sheets have been shown to prevent cryptocaryoniasis. Therefore, we studied the potential efficiency of copper alloy mesh (CAM) in aquaculture tanks to prevent cryptocaryoniasis outbreaks. The effectivenesses of CAM against the tomont stage of Cryptocaryon irritans and in protecting fish from cryptocaryoniasis were tested both in vitro and in vivo. The mortality rate of C. irritans tomonts increased as the contact time with CAM rose and peaked at 70 min (100% of mortality). Morphological changes were observed such as the shrinking of the protoplasm of the treated tomonts, resulting in a larger gap between the cytoplasm and the cyst wall. Mitochondrial dysfunction due to shrinkage in the inner portion, outer and inner mitochondrial membrane damage and cytoplasmic vacuolation was revealed by ultrastructural analysis. The use of CAM effectively preventing reinfection was also provided. In comparison with group B (infected fish without CAM), both groups A (uninfected fish as a control group) and C (infected fish treated with CAM) had a 100% survival rate until the end of the trial. CAM has the same anticryptocaryoniasis effect as copper alloy sheets but is more advantageous due to its lightweight, reduced labor cost and lower purchase cost. It is noticeable that CAM exposure also prevents the excessive accumulation of copper ions in aquaculture sea water.

Role of Copper on Mitochondrial Function and Metabolism

Copper is essential for life processes like energy metabolism, reactive oxygen species detoxification, iron uptake, and signaling in eukaryotic organisms. Mitochondria gather copper for the assembly of cuproenzymes such as the respiratory complex IV, cytochrome c oxidase, and the antioxidant enzyme superoxide dismutase 1. In this regard, copper plays a role in mitochondrial function and signaling involving bioenergetics, dynamics, and mitophagy, which affect cell fate by means of metabolic reprogramming. In mammals, copper homeostasis is tightly regulated by the liver. However, cellular copper levels are tissue specific. Copper imbalances, either overload or deficiency, have been associated with many diseases, including anemia, neutropenia, and thrombocytopenia, as well as tumor development and cancer aggressivity. Consistently, new pharmacological developments have been addressed to reduce or exacerbate copper levels as potential cancer therapies. This review goes over the copper source, distribution, cellular uptake, and its role in mitochondrial function, metabolic reprograming, and cancer biology, linking copper metabolism with the field of regenerative medicine and cancer.

Cu-induced mitochondrial dysfunction is mediated by abnormal mitochondrial fission through oxidative stress in primary chicken embryo hepatocytes

BACKGROUND

Excess copper (Cu) is an oxidative stress factor which associates with a variety of diseases. The aim of this study was to evaluate the effect of Cu in primary chicken embryo hepatocytes (CEHs).

METHODS

CEHs were isolated from 13 days old chicken embryos and followed by different concentration Cu (0, 10, 100, 200 μM) and/or ALC treatment (0.3 mg/mL) for 12 or 24 h. The effects of Cu exposure in CEHs were determined by detecting reactive oxygen species (ROS), malondialdehyde (MDA), mitochondrial membrane potential (MMP), and ATP levels. The expression of mitochondrial dynamics-related genes and proteins were also detected.

RESULTS

Results showed that Cu treatment (100 or 200 μM) significantly decreased CEHs viability, MMP and ATP levels, increased ROS and MDA levels in 12 or 24 h. The up-regulated mitochondrial fission genes and protein in 100 and 200 μM Cu groups suggested Cu promoted mitochondrial division but not fusion. However, the co-treatment of ALC and Cu alleviated those changes compared with the 100 or 200 μM Cu groups.

CONCLUSION

In conclusion, we speculated that Cu increased the oxidative stress and induced mitochondria dysfunction via disturbing mitochondrial dynamic balance in CEHs, and this process was not completely reversible.

Autophagy attenuates copper-induced mitochondrial dysfunction by regulating oxidative stress in chicken hepatocytes

Copper (Cu) is an essential trace element that is required for the catalysis of several cellular enzymes. Excessive Cu could induce hepatotoxicity in humans and multiple animals. The purpose of this study was to investigate the effects of autophagy machinery on Cu-induced hepatotoxicity. Chicken hepatocytes were cultured in medium in the absence and presence of Cu sulfate (CuSO₄) (0, 10, 50, and 100 μM) for 0, 6, 12, and 24 h, and in the combination of CuSO₄ and N-acetyl-l-cysteine (NAC) (1 mM), rapamycin (10 nM), and 3-methyladenine (3-MA) (5 mM) for 24 h. Results showed that Cu could markedly increase the number of autophagosomes and LC3 puncta, induce autophagy-related genes (Beclin1, ATG5, LC3Ⅰ, LC3Ⅱ, mTOR, and Dynein) mRNA expression and proteins (BECN1, LC3Ⅱ/LC3Ⅰ) expression. NAC could relieve Cu-induced the changes of above genes and proteins. Additionally, rapamycin attenuated Cu-induced the increased lactic dehydrogenase (LDH), aspartate amino transferase (AST), and alanine aminotransferase (ALT) activities, and SOD-1 mRNA expression as well as the decreased cell viability, reactive oxygen species (ROS), hydrogen peroxide, total superoxide dismutase (T-SOD), malonaldehyde (MDA), catalase (CAT), HO-1 mRNA expression, adenosine triphosphate (ATP) levels, mitochondrial mass, and mitochondria membrane potential (MMP). But 3-MA had the opposite effects on above factors. Collectively, these findings provide strong evidence that Cu could induce autophagy by generating excessive ROS in hepatocytes, and autophagy might attenuate Cu-induced mitochondrial dysfunction by regulating oxidative stress.