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Copper (Cu) as a transition metal can be toxic to public and ecosystem health at high level, but the specific mechanism of Cu-evoked nephrotoxicity remains elusive. Here, we first revealed the crosstalk between mitofusin2 (Mfn2)-dependent mitochondria-associated endoplasmic reticulum membrane (MAM) dynamics and autophagy in duck renal tubular epithelial cells under Cu exposure. Primary duck renal tubular epithelial cells were treated with 100 and 200 μM Cu sulfate for 12 h and exposed to lentivirus to deliver mitofusin2 (Mfn2). We found that excessive Cu disrupted MAM integrity, decreased the mitochondrial calcium level, co-localization of IP3R and VDAC1, the mRNA levels of PACS2, Mfn2, IP3R and MCU, and Mfn2 and VDAC1 protein levels, causing MAM dysfunction. Furthermore, Mfn2 overexpression ameliorated Cu-induced MAM dysfunction, and increased Cu-evoked autophagy in duck renal tubular epithelial cells accompanied with the elevation of autophagosomes number, ROS level, LC3 puncta, Atg5 and LC3B mRNA levels, and Beclin1, Atg14, LC3BII/LC3BI protein levels. Accordingly, our data proved that excessive Cu could trigger MAM dysfunction and autophagy in duck renal tubular epithelial cells, and Cu-induced autophagy could be activated through Mfn2-dependent MAM, providing evidence on the toxicological exploration mechanisms of Cu., (Copyright © 2022 The Authors. Published by Elsevier Inc. All rights reserved.)

The aim of this study was to investigate the crosstalk between oxidative stress and autophagy through the ROS/HO-1/NQO1 pathway caused by copper (Cu). Duck renal tubular epithelial cells were treated in Cu sulfate (CuSO 4 ) (0, 100 and 200 μM) for 12 h, and in the combination of CuSO 4 (200 μM) and reactive oxygen species (ROS) scavenger (butyl hydroxyanisole, BHA, 100 μM), or HO-1 inhibitor (zinc protoporphyrin, ZnPP, 10 μM) for 12 h. Results revealed that Cu could significantly elevate the levels of intracellular ROS, superoxide dismutase, hydrogen peroxide, malondialdehyde, glutathione, simultaneously reduce catalase and glutathione peroxidase levels, and upregulate HO-1, SOD-1, CAT, NQO1, GCLM mRNA levels and HO-1, SOD-1 protein levels. Additionally, Cu could observably increase the number of autophagosomes, acidic vesicle organelles (AVOs) and LC3 puncta; upregulate mRNA levels of mTOR, Beclin-1, ATG7, ATG5, ATG3, LC3II and protein levels of Beclin-1, LC3II/LC3I, downregulate LC3I mRNA level. Both treatments with BHA and ZnPP could significantly alleviate the changes of antioxidant indexes levels and ROS accumulation, reduce the increase of the number of autophagosomes, AVOs and LC3 puncta, and mitigate the above changed oxidative stress and autophagy related mRNA and protein levels induced by Cu. In summary, our findings indicated that excessive Cu could induce oxidative stress and autophagy by activating the ROS/HO-1/NQO1 pathway, and inhibition of HO-1 might attenuate Cu-induced oxidative stress and autophagy in duck renal tubular epithelial cells., Competing Interests: Declaration of competing interest The authors declare that there is no conflict of interest., (Copyright © 2020 Elsevier B.V. All rights reserved.)

The aim of the present study was to investigate the effects of high concentrations of copper (Cu) on the cecum and rectum of intestinal microbiota in female mice. Twenty-four Kunming mice were weighed and randomly divided into two groups (n = 12 per group) including the control group and Cu group. Cu group was given drinking water with 5 mg/kg-bw copper chloride (CuCl 2 ), while the control group was treated with drinking water without CuCl 2 . At the 90th day, results showed that compared with the control group, mice in the treatment group had a lower body weight, and the feces turned yellow and had a lower pH value. Histopathological lesions showed that the intestinal tissue from the treatment group had increased thickness of outer muscularis and smoothed muscle fiber, widened submucosa, decreased goblet cells, and showed blunting of intestinal villi and severe atrophy of central lacteal. In addition, at the genus level, 16S rRNA gene sequencing from the Cu group showed that Corynebacterium were significantly increased whereas Staphylococcaceae, Odoribacter, Rikenella, and Jeotgalicoccus were significantly decreased in the cecum. Dehalobacterium, Coprococcus, and Spirochaetales increased significantly whereas Salinicoccus, Bacillales, Staphylococcus, and Lactobacillales decreased sharply in the rectum. This study demonstrated that high concentrations of Cu could induce tissue injury and interrupt the homeostasis of microbiota.

The aim of the present study was to investigate the effects of high doses of copper (Cu) and mercury (Hg) on the cecal microbiota in female mice. Forty-eight Kunming mice were randomly divided into the control group (CCk group), the Cu group (CCu group), the Hg group (CHg group), and the Cu + Hg group (CCH group). At the 90th day, cecal tissues were prepared for histopathological analysis and cecal contents for analysis by 16S rRNA sequencing method. Cecal tissues from treatment groups had histopathological lesions including increased thickness of inner muscularis and outer muscularis, widened submucosa, decreased goblet cells, mild to moderate necrosis of enterocytes, blunting of intestinal villi, and severe atrophy of central lacteal. Furthermore, compared to the CCk group, the abundance of bacteria genera Rikenella, Jeotgailcoccus, and Staphylococcus were significantly decreased, whereas the bacteria genus Corynebacterium was significantly increased in the CCu group. The abundance of bacteria genera of Sporosarcina, Jeotgailcoccus, and Staphylococcus were significantly decreased in the CHg group and CCH group. The bacteria genus Anaeroplasma was significantly increased in the CCH group. The results indicated that high doses of Cu and Hg caused histopathological lesions and changed the diversity of microbiota in the cecum of female mice, which provide a theoretical basis for more accurate assessment of the risk in intestinal diseases caused by Cu and Hg.

The accumulation of copper (Cu) in the organisms could lead to kidney damage by causing mitochondrial dysfunction. Given that mitochondria are one of the targets of Cu poisoning, this study aimed to investigate the role of mitophagy in Cu‐induced mitochondrial dysfunction in renal tubular epithelial cells to understand the mechanism of Cu nephrotoxicity. Hence, the cells were treated with different concentrations of Cu sulfate (CuSO4) (0, 100, and 200 μM), and mitophagy inhibitor (Cyclosporine A, 0.5 μM) and/or 200 μM CuSO4 in the combination for 12 h. Results showed that Cu caused mitochondrial swelling, vacuoles, and cristae fracture; increased the number of mitochondrial and lysosome fluorescent aggregation points; upregulated the mRNA levels of mitophagy‐associated genes (LC3A, LC3B, P62, BNIP3, NIX, OPTN, NDP52, Cyp D LAMP1, and LAMP2) and protein levels of LC3II/LC3I, BNIP3, and NIX, downregulated the mRNA and protein levels of P62; reduced the mitochondrial membrane potential (MMP), ATP content, mitochondrial respiratory control rate (RCR), mitochondrial respiratory control rate (OPR), and the mRNA and protein levels of PGC‐1α, TOMM20, and Mfn2, but increased the mRNA and protein levels of Drp1. Besides, cotreatment with Cu and CsA dramatically decreased the level of mitophagy, but increased mitochondrial division, further reduced MMP, ATP content, RCR, and OPR, mitochondrial fusion and thereby reduced mitochondrial biogenesis. Taken together, these data indicated that Cu exposure induced BNIP3/NIX‐dependent mitophagy in duck renal tubular epithelial cells, and inhibition of mitophagy aggravated Cu‐induced mitochondrial dysfunction. [ABSTRACT FROM AUTHOR]

Copper (Cu) is an important trace element with a two-sided effect on the growth performance of animals, which depends on the timing and dosage of Cu addition, etc. The purpose of this study was to determine the effects of oral copper sulfate (CuSO4, 350 ppm) on growth performance, cecal morphology, and its microflora of chickens (n = 60) after 30, 60, and 90 days. The results showed that after 90 days of copper exposure, the chickens lost weight, the cecum mucosa was detached, and vacuolation and inflammatory infiltration occurred at the base of the lamina propria. In addition, using the 16S rDNA sequencing method, we observed that copper exposure changed the richness and diversity of intestinal microorganisms. At the phylum level, Proteobacteria and Actinobacteria both significantly increased, while Bacteroidetes significantly decreased in the Cu group compared with control check (CK) group. At the genus level, the relative abundance of Rikenellaceae_RC9_gut_group decreased significantly, while Ruminococcaceae_UCG-014, Lachnoclostridium , and [Eubacterium]_coprostanoligenes_group increased significantly after copper exposure, and the change in microflora was most significant at 90 days. Moreover, the relevance of genus-level bacteria was altered. PICRUST analysis revealed potential metabolic changes associated with copper exposure, such as Staphylococcus aureus infection and metabolic disorders of nutrients. To sum up, these data show that subchronic copper exposure not only affects the growth and development of chickens but also causes the imbalance of intestinal microflora, which may further induce metabolic disorders in chickens. [ABSTRACT FROM AUTHOR]

Copper (Cu) and mercury (Hg) are major pollutants worldwide, but the gastrointestinal damage caused by copper and mercury exposure is unclear. We are committed to scientific research on the harm and transformation of copper and mercury exposure to the rectal microbial population of female mice. Kunming mice (n = 24) were randomly divided into four equal groups, i.e., 1) Rectal Colon Control (RCK) group, 0 mg/kg of Cu and Hg), 2) Rectal Copper (RCu group), 5 mg/kg weight of Cu), 3) Rectal Mercury (RHg) group, 2 mg/kg weight of Hg) and 4) Rectal copper-mercury (RCH) group, 2.5 and 1 mg/kg weight of Cu and Hg. On the 90th day, the rectal and intestinal tissues were analyzed for pathophysiology, and quantitative analysis by PCR, then a library was prepared, and sequencing was carried out. The rectal tissue of the RCu and RCH group had histopathological and physiological damage, including low weight, low pH value, increased thickness of the outer muscle layer, smooth muscle tissue, widening of the submucosal layer, reduction of goblet cells, blunt intestinal villi and severe aging of the central mammary duct. In addition, Sequencing results of 16S rRNA genes compared with RCK showed that the abundance of the Treponema, Coprococcus, and Dehalobacterium in RCu was more significant than the RCK. Still, the bacillus, Jeotgalicoccus, Salinicoccus, Staphylococcus, and Ignatzschineria was just the opposite. The abundance of Butyricimonas, Streptococcus, Dehalobacterium, Coprococcus, Oscillospira, and Helicobacter in RHg was more significant than in the RCK. Still, Corynebacterium, Bacillus, Jeotgalicoccus, Salinicoccus, Staphylococcus, Lactococcus, and Ignatzschineria were the opposite. We found some similar exciting things. The abundance of the Dehalobacterium, Coprococcus, and Oscillospira was significantly more significant than the RCK. Still, the Corynebacterium, Salinicoccus, Jeotgalicoccus, Staphylococcus, Lactococcus, Sutterella, and Ignatzschineria were the opposite. In addition, the Staphylococcus in RCu was increased than in the RCH, and the Streptococcus in RCu was increased than in the RCH. The results of the present study furnish a source for a more precise validation of the risk of digestive tract diseases driven by Cu and Hg. [ABSTRACT FROM AUTHOR]

Copper (Cu) is a vital micronutrient required for numerous fundamental biological processes, but excessive Cu poses potential detrimental effects on public and ecosystem health. However, the molecular details linking endoplasmic reticulum (ER) stress and apoptosis in duck renal tubular epithelial cells have not been fully elucidated. In this study, duck renal tubular epithelial cells exposed to Cu sulfate (CuSO 4) (0, 100 and 200 μM) and a PERK inhibitor (GSK2606414, GSK, 1 μM) for 12 h were used to investigate the crosstalk between ER stress and apoptosis under Cu exposure. Cell and ER morphological and functional characteristics, intracellular calcium (Ca2+) levels, apoptotic rates, ER stress and apoptosis-related mRNA and protein levels were examined. The results showed that excessive Cu could cause ER expansion and swelling, increase the expression levels of ER stress-associated genes (PERK, eIF2α, ATF4 and CHOP) and proteins (p-PERK and CHOP), induce intracellular Ca2+ overload, upregulate the expression levels of apoptosis-associated genes (Bax, Bak1, Caspase9 and Caspase3) and the cleaved-Caspase3 protein, downregulate Bcl-xl and Bcl2 mRNA levels and trigger apoptosis. PERK inhibitor treatment could ameliorate the above changed factors caused by Cu. In conclusion, these findings indicate that excessive Cu could trigger ER stress via activation of the PERK/ATF4/CHOP signaling pathway and that ER stress might aggravate Cu-induced apoptosis in duck renal tubular epithelial cells. Image 1 • Copper (Cu) has toxic effect on duck renal tubular epithelial cells. • Cu could trigger endoplasmic reticulum (ER) stress via PERK/ATF4/CHOP pathway. • Cu could induce apoptosis in duck renal tubular epithelial cells. • ER stress might aggravate Cu-induced apoptosis via PERK/ATF4/CHOP pathway. [ABSTRACT FROM AUTHOR]