Molybdenum and Cadmium Co-induce Pyroptosis via Inhibiting Nrf2-Mediated Antioxidant Defense Response in the Brain of Ducks

Quercetin attenuates cadmium-induced hepatotoxicity by suppressing oxidative stress and apoptosis in rat

BACKGROUND

Cadmium (Cd) is considered a major industrial and environmental toxicant, threatening the health of aquatic organisms, plants, animals, and humans. Quercetin (Que) is a natural flavonoid with antioxidant properties. The purpose of this study was to investigate the role of the oxidative stress and apoptosis in Cd-induced hepatotoxicity and the protective effect of Que.

METHODOLOGY

Thirty-six male SD rats were randomly divided into 6 groups: control group, 1 mg/kg Cd group, 2 mg/kg Cd group, 1 mg/kg Cd+Que group, 2 mg/kg Cd + Que group, and a Que group. After a feeding period of 28 days, serum and liver tissue samples were collected to evaluate liver function, oxidative stress levels, liver histology, and apoptosis.

RESULTS

Experimental results confirmed that compared with the control group, the body weights of the Cd group significantly decreased. Additionally, there was a tremendous increased in the levels of ALT, AST, and LDH, and a significant decreased in the activities of SOD, CAT, and GSH content, while the level of MDA increased. Pathological sections of the liver showed that Cd-induced rats had ruptured liver tissue cells, exposed nuclei, and disturbed arrangement of hepatocyte cords. Cd exposure decreased the mRNA and protein expression of Nrf2 and NQO1 while increased the mRNA and protein expression of Keap1, thereby inducing oxidative stress. Meanwhile, Cd exposure increased the mRNA and protein expressions of Cytc, caspase-9, caspase-3, and Bax, while decreased the expression of Bcl-2. Conversely, after Que addition of alleviated liver injury and oxidative stress induced by Cd and inhibited apoptosis.

CONCLUSION

In conclusion, Que alleviates hepatic toxicity induced by Cd through suppression of oxidative stress and apoptosis.

The interplay of transition metals in ferroptosis and pyroptosis

Cell death is one of the most important mechanisms of maintaining homeostasis in our body. Ferroptosis and pyroptosis are forms of necrosis-like cell death. These cell death modalities play key roles in the pathophysiology of cancer, cardiovascular, neurological diseases, and other pathologies. Transition metals are abundant group of elements in all living organisms. This paper presents a summary of ferroptosis and pyroptosis pathways and their connection to significant transition metals, namely zinc (Zn), copper (Cu), molybdenum (Mo), lead (Pb), cobalt (Co), iron (Fe), cadmium (Cd), nickel (Ni), mercury (Hg), uranium (U), platinum (Pt), and one crucial element, selenium (Se). Authors aim to summarize the up-to-date knowledge of this topic.In this review, there are categorized and highlighted the most common patterns in the alterations of ferroptosis and pyroptosis by transition metals. Special attention is given to zinc since collected data support its dual nature of action in both ferroptosis and pyroptosis. All findings are presented together with a brief description of major biochemical pathways involving mentioned metals and are visualized in attached comprehensive figures.This work concludes that the majority of disruptions in the studied metals' homeostasis impacts cell fate, influencing both death and survival of cells in the complex system of altered pathways. Therefore, this summary opens up the space for further research.

Nickel Induces Pyroptosis via the Nrf2/NLRP3 Pathway in Kidney of Mice

Nickel (Ni) is considered a toxic metal, and excessive exposure can cause kidney damage. This study was designed to explore whether nickel chloride (NiCl2) can induce cell pyroptosis and its possible mechanism. Here, we found that NiCl2 treatment could reduce the kidney index and result in kidney damage. Meanwhile, NiCl2 could obviously induce renal pyroptosis, which was characterized by an increase in IL-18, IL-1β, NLRP3, and GSDMD expression. Furthermore, NiCl2 induced pyroptosis through the Nrf2/NLRP3 pathway which featured down-regulated protein and mRNA expression levels of Nrf2 and up-regulated protein and mRNA expression levels of Caspase-1, NLRP3, and GSDMD. In summary, excessive Ni exposure can induce renal cell pyroptosis, ultimately leading to kidney tissue damage and hindering normal development, and its possible mechanism may be due to the inhibition of the Nrf2 pathway.

From ferroptosis to cuproptosis, and calcicoptosis, to find more novel metals-mediated distinct form of regulated cell death

Regulated cell death (RCD), also known as programmed cell death (PCD), plays a critical role in various biological processes, such as tissue injury/repair, development, and homeostasis. Dysregulation of RCD pathways can lead to the development of many human diseases, such as cancer, neurodegenerative disorders, and cardiovascular diseases. Maintaining proper metal ion homeostasis is critical for human health. However, imbalances in metal levels within cells can result in cytotoxicity and cell death, leading to a variety of diseases and health problems. In recent years, new types of metal overload-induced cell death have been identified, including ferroptosis, cuproptosis, and calcicoptosis. This has prompted us to examine the three defined metal-dependent cell death types, and discuss other metals-induced ferroptosis, cuproptosis, and disrupted Ca2+ homeostasis, as well as the roles of Zn2+ in metals' homeostasis and related RCD. We have reviewed the connection between metals-induced RCD and various diseases, as well as the underlying mechanisms. We believe that further research in this area will lead to the discovery of novel types of metal-dependent RCD, a better understanding of the underlying mechanisms, and the development of new therapeutic strategies for human diseases.

Molybdenum and cadmium co-induce apoptosis and ferroptosis through inhibiting Nrf2 signaling pathway in duck (Anas platyrhyncha) testes

Cadmium (Cd) and high molybdenum (Mo) are injurious to the body. Previous research has substantiated that Cd and Mo exposure caused testicular injury of ducks, but concrete mechanism is not fully clarified. To further survey the toxicity of co-exposure to Cd and Mo in testis, 40 healthy 8-day-old Shaoxing ducks (Anas platyrhyncha) were stochasticly distributed to 4 groups and raised with basic diet embracing Cd (4 mg/kg Cd) or Mo (100 mg/kg Mo) or both. At the 16th wk, testis tissues were gathered. The characteristic ultrastructural changes related to apoptosis and ferroptosis were observed in Mo or Cd or both groups. Besides, Mo or Cd or both repressed nuclear factor erythroid 2-related factor 2 (Nrf2) pathway via decreasing Nrf2, Heme oxygenase-1 (HO-1), NAD(P)H quinone oxidoreductase 1 (NQO1), Glutamate-cysteine ligase catalytic subunit (GCLC) and Glutamate-cysteine ligase modifier subunit (GCLM) mRNA expression of and Nrf2 protein expression, then stimulated apoptosis by elevating Bcl-2 antagonist/killer-1 (Bak-1), Bcl-2-associated X-protein (Bax), Cytochrome complex (Cyt-C), caspase-3 mRNA expression, cleaved-caspase-3 protein expression and apoptosis rate, as well as reducing B-cell lymphoma-2 (Bcl-2) mRNA expression and ratio of Bcl-2 to Bax, and triggered ferroptosis by upregulating Acyl-CoA Synthetase Long Chain Family Member 4 (ACSL4), transferrin receptor (TFR1) and Prostaglandin-Endoperoxide Synthase 2 (PTGS2) expression levels, and downregulating ferritin heavy chain 1 (FTH1), ferritin light chain 1 (FTL1), ferroportin 1 (FPN1), solute carrier family 7 member 11 (SCL7A11) and glutathione peroxidase 4 (GPX4) expression levels. The most obvious changes of these indexes were observed in co-treated group. Altogether, the results announced that Mo or Cd or both evoked apoptosis and ferroptosis by inhibiting Nrf2 pathway in the testis of ducks, and co-exposure to Mo and Cd exacerbated these variations.

Nanomaterials-induced programmed cell death: Focus on mitochondria

Nanomaterials are widely utilized in several domains, such as everyday life, societal manufacturing, and biomedical applications, which expand the potential for nanomaterials to penetrate biological barriers and interact with cells. Multiple studies have concentrated on the particular or improper utilization of nanomaterials, resulting in cellular death. The primary mode of cell death caused by nanotoxicity is programmable cell death, which includes apoptosis, ferroptosis, necroptosis, and pyroptosis. Based on our prior publications and latest research, mitochondria have a vital function in facilitating programmed cell death caused by nanomaterials, as well as initiating or transmitting death signal pathways associated with it. Therefore, this review takes mitochondria as the focal point to investigate the internal molecular mechanism of nanomaterial-induced programmed cell death, with the aim of identifying potential targets for prevention and treatment in related studies.

Mitochondria-associated endoplasmic reticulum membrane as a mediator of vanadium-induced endoplasmic reticulum quality control in duck brains

Vanadium (V) plays a crucial role in normal cells, but excess V causes multi-organ toxicity, including neurotoxicity. Mitochondria-associated endoplasmic reticulum membrane (MAM) is a dynamic structure between endoplasmic reticulum (ER) and mitochondria that mediates ER quality control (ERQC). To explore the effects of excess V on MAM and ERQC in the brain, 72 ducks were randomly divided into two groups: the control group (basal diet) and the V group (30 mg V/kg basal diet). On days 22 and 44, brain tissues were collected for histomorphological observation and determination of trace element contents. In addition, the mRNA and protein levels of MAM and ERQC-related factors in the brain were analyzed. Results show that excessive V causes the imbalance of trace elements, the integrity disruption of MAM, rupture of ER and autophagosomes formation. Moreover, it inhibits IP3R and VDAC1 co-localization, down-regulates the expression levels of MAM-related factors, but up-regulates the expression levels of ERQC and autophagy related factors. Together, results indicate that V exposure causes disruption of MAM and activates ERQC, which is further causing autophagy.

Copper Deficiency Induces Oxidative Stress in Liver of Mice by Blocking the Nrf2 Pathway

Copper (Cu) is an essential metal required for many physiological processes and biological reactions. Liver is the main organ of metabolism of Cu and is also the site where synthesis of some metalloproteins. The purpose of this study is to explore the effects of Cu deficiency on the liver and to evaluate the changes in liver oxidative stress levels to reveal its possible impact mechanisms. Mice were feed to a nutritional Cu-deficiency diet from weaning and injected with copper sulfate (CuSO4) intraperitoneally to correct Cu deficiency. Cu deficiency resulted in reduced liver index, liver histological alteration, and oxidative stress; decreased the contents of Cu and ALB; elevated ALT and AST concentrations in serum together with decreased mRNA and protein expressions of Nrf2 pathway related molecules (Nrf2, HO-1, NQO1); and increased mRNA and protein expressions of Keap1. However, the supplement of copper sulfate (CuSO4) significantly ameliorated the changes mentioned above. Our results indicate that Cu deficiency can cause hepatic damage in mice is associated with the activation of oxidative stress and inhibition of Nrf2 pathway.

Co-exposure to Environmentally Relevant Levels of Molybdenum and Cadmium Induces Oxidative Stress and Ferroptosis in the Ovary of Ducks

Excessive doses of molybdenum (Mo) and cadmium (Cd) have toxic effects on animals. Nevertheless, the reproductive toxicity elicited by Mo and Cd co-exposure remains obscure. To evaluate the co-induce toxic impacts of Mo and Cd on ovaries, 8-day-old 40 healthy ducks were stochastically distributed to four groups and were raised a basal diet supplemented with Cd (4 mg/kg Cd) and/or Mo (100 mg/kg Mo). In the 16th week, ovary tissues were gathered. The data revealed that Mo and/or Cd decreased GSH content, CAT, T-SOD, and GSH-Px activities and increased MDA and H2O2 levels. Moreover, there was a significant decrease in nuclear Nrf2 protein level and its related downstream factors, while cytoplasmic Nrf2 protein level showed a substantial increase. Additionally, a marked elevation was observed in ferrous ion content and TFRC, GCLC, SLC7A11, ACSL4, and PTGS2 expression levels, while FTH1, FTL1, FPN1, and GPX4 expression levels were conversely reduced. These indicators exhibited more marked changes in the joint exposure group. In brief, our results announced that Mo and/or Cd resulted in oxidative stress and ferroptosis in duck ovaries. Synchronously, the Cd and Mo mixture intensified the impacts.

Cadmium neurotoxicity and therapeutic strategies

Cadmium (Cd) is a multitarget, carcinogenic, nonessential environmental pollutant. Due to its toxic effects at very low concentrations, lengthy biological half-life, and low excretion rate, exposure to Cd carries a concern. Prolonged exposure to Cd causes severe injury to the nervous system of both humans and animals. Nevertheless, the precise mechanisms responsible for the neurotoxic effects of Cd have yet to be fully elucidated. The accurate chemical mechanism potentially entails the destruction of metal-ion homeostasis, inducing oxidative stress, apoptosis, and autophagy. Here we review the evidence of the neurotoxic effects of Cd and corresponding strategies to protect against Cd-induced central nervous system injury.

Role of PLC/IP3 /IP3 R axis in excess molybdenum exposure induced apoptosis in duck renal tubular epithelial cells

Excess molybdenum (Mo) is harmful to animals, but its nephrotoxicity has not been comprehensively explained. To appraise the influences of excess Mo on Ca homeostasis and apoptosis via PLC/IP3 /IP3 R axis, primary duck renal tubular epithelial cells were exposed to 480 μM and 960 μM Mo, and joint of 960 μM Mo and 10 μM 2-APB or 0.125 μM U-73122 for 12 h (U-73122 pretreated for 1 h), respectively. The data revealed that the increment of [Ca2+ ]c induced by Mo mainly originated from intracellular Ca storage. Mo exposure reduced [Ca2+ ]ER , elevated [Ca2+ ]mit , [Ca2+ ]c , and the expression of Ca homeostasis-related factors (Calpain, CaN, CRT, GRP94, GRP78 and CaMKII). 2-APB could effectively reverse subcellular Ca2+ redistribution by inhibiting IP3 R, which confirmed that [Ca2+ ]c overload induced by Mo originated from ER. Additionally, PLC inhibitor U-73122 remarkably mitigated the change, and dramatically reduced the number of apoptotic cells, the expression of Bak-1, Bax, cleaved-Caspase-3/Caspase-3, and notably increased the expression of Bcl-xL, Bcl-2, and Bcl-2/Bax ratio. Overall, the results confirmed that the Ca2+ liberation of ER via PLC/IP3 /IP3 R axis was the main cause of [Ca2+ ]c overload, and then stimulated apoptosis in duck renal tubular epithelial cells.

Glycosides of Buyang Huanwu decoction inhibits pyroptosis associated with cerebral ischemia-reperfusion through Nrf2-mediated antioxidant signaling pathway both in vivo and in vitro

BACKGROUND

Glycosides are the pharmacodynamic substances of Buyang Huanwu Decoction (BYHWD) and they exert a protective effect in the brain by inhibiting neuronal pyroptosis of cerebral ischemia-reperfusion (CIR). However, the mechanism by which glycosides regulate neuronal pyroptosis of CIR is still unclear.

PURPOSE

A significant part of this study aimed to demonstrate whether glycosides have an anti-pyroptotic effect on CIR by nuclear factor erythroid 2-related factor (Nrf2)-mediated antioxidative mechanism.

METHODS

Rats were used in vivo models of middle cerebral artery occlusion and reperfusion (MCAO/R). Neuroprotective effect of glycosides after Nrf2 inhibiting was observed by nerve function score, Nissl staining, Nrf2 fluorescence staining and pyroptotic proteins detection. SH-SY5Y cells were used in vitro models of oxygen-glucose deprivation/reperfusion (OGD/R). Glycosides was evaluated for their effects by measuring cell morphology, survival rate, lactate dehydrogenase (LDH) rate and expression of pyroptotic proteins. Nrf2 si-RNA 54-1 interference with lentivirus was used to create silenced Nrf2 SH-SY5Y cells (si-Nrf2-SH-SY5Y). Glycosides were evaluated on si-Con-SH-SY5Y and si-Nrf2-SH-SY5Y cells based on the expression of Nrf2 signaling pathway, pyroptotic proteins and cell damage manifestation.

RESULTS

In vivo, glycosides significantly promoted the fluorescence level of nuclear Nrf2, added more Nissl bodies, reduced neurological function scores and inhibited the pyroptotic proteins level. In vitro, glycosides significantly repaired the morphological damage of cells, promoted the survival rate, reduced the LDH rate, inhibited the pyroptosis. Moreover, antioxidant activity of glycosides was enhanced via Nrf2 activation. Both Nrf2 blocking in vivo and Nrf2 silencing in vitro significantly weakened the pyroptosis inhibitory and neuroprotective effects of glycosides.

CONCLUSION

These results suggested for the first time that glycosides inhibited neuronal pyroptosis by regulating the Nrf2-mediated antioxidant stress pathway, thereby exerting brain protection of CIR. As a result of this study, This study improved understanding of the pharmacodynamics and mechanism of BYHWD, as well as providing a Traditional Chinese Medicine (TCM) treatment strategy for CIR .

Upregulation of postsynaptic cAMP/PKA/CREB signaling alleviates copper(Ⅱ)-induced oxidative stress and pyroptosis in MN9D cells

It has been widely reported that long-term exposure to copper increases the prevalence and mortality of Parkinson's disease. Our previous study showed that CuSO₄ exposure induced a significant increase in the expression of cleaved Caspase1 proteins and the loss of dopaminergic neurons in the SNpc of mice. In this study, the effects of copper(Ⅱ) on cAMP/PKA/CREB pathway and pyroptosis-related proteins in MN9D cells were investigated by setting up copper(Ⅱ) exposure groups with different concentration gradients, to provide possible molecular evidence for studying the mechanism of copper(Ⅱ)-induced degeneration of dopaminergic neurons. We found that after 48hours of copper(Ⅱ) exposure, the cu content in MN9D cells increased in a dose-dependent manner, and the proliferation activity decreased significantly. In addition, copper(Ⅱ) exposure caused up-regulation of PDE4D and down-regulation of D1R, cAMP, PKA and p-CREB/CREB. Simultaneously, we proved that copper(Ⅱ) exposure induced oxidative stress in MN9D cells, including decreased GSH-Px content, Keap1 expression and mitochondrial membrane potential, increased malondialdehyde content, ROS intensity, and Nrf2, NQO1, HO-1, HSP-70 expression, further causing up-regulation of inflammasome and GSDMD protein. After pretreatment with Roflupram, the level of copper(Ⅱ)-induced oxidative damage decreased, the expression of inflammasome and GSDMD proteins were down-regulated. However, the protective effects of ROF were blocked by H-89. In summary, copper(Ⅱ) treatment induced oxidative stress and inflammasome-mediated pyroptosis in MN9D cells, which may be related to copper(Ⅱ)-induced postsynaptic cAMP, PKA, and CREB signal transduction disorders.

Duck gasdermin E is a substrate of caspase-3/-7 and an executioner of pyroptosis

Gasdermin (GSDM)-mediated cell death is an ancient immune defensive mechanism that plays an essential role in bacteria, fungi, coral, teleost, and mammals. After being cleaved by proteases of hosts or pathogens, amino-terminal (NT) fragment of GSDMs (GSDM-NTs) form pores in the membrane structure of cells, thereby leading to pyroptotic cell death. However, the expression profile, activation mechanism and function of avian GSDMs have not been studied in depth yet. In the current study, genes encoding duck gasdermin E (duGSDME), caspase-3 (ducaspase-3) and ducaspase-7 were cloned from mRNA of a virus-challenged duck embryo. The cleavage of duGSDME by ducaspase-3/-7 was verified in the cell-free system and/or in human embryonic kidney cells (HEK293). Ducaspase-3/-7 could recognize and cleave duGSDME at 270DAVD273. Overexpression of duGSDME-NT (1-273aa) fragment led to pyroptosis-like morphological change, increased lactic dehydrogenase (LDH) release and propidium iodide uptake of HEK293 cells, which indicated that duGSDME-NTs could cause cell membrane damage. In addition, recombinantly expressed duGSDME-NT showed bactericidal activity to an enterotoxic Escherichia coli (F5+) strain. The expression level of duGSDME was low in duckling tissues. DHAV-3 challenge upregulated the expression of duGSDME and ducaspase-3 in different tissues and led to the activation of ducaspase-3 and cleavage of duGSDME. The results indicated that duGSDME is a substrate of ducapsase-3/-7, and duGSDME-NT can cause pyroptosis. In addition, duGSDME may play a role in the immune defense of ducks against infectious diseases after being cleaved by ducaspase-3. The current study provides essential information for further investigation of the mechanisms of avian innate immunity and avian diseases.

The Effect of Oxidative Stress-Induced Autophagy by Cadmium Exposure in Kidney, Liver, and Bone Damage, and Neurotoxicity

Environmental and occupational exposure to cadmium has been shown to induce kidney damage, liver injury, neurodegenerative disease, and osteoporosis. However, the mechanism by which cadmium induces autophagy in these diseases remains unclear. Studies have shown that cadmium is an effective inducer of oxidative stress, DNA damage, ER stress, and autophagy, which are thought to be adaptive stress responses that allow cells exposed to cadmium to survive in an adverse environment. However, excessive stress will cause tissue damage by inducing apoptosis, pyroptosis, and ferroptosis. Evidently, oxidative stress-induced autophagy plays different roles in low- or high-dose cadmium exposure-induced cell damage, either causing apoptosis, pyroptosis, and ferroptosis or inducing cell survival. Meanwhile, different cell types have different sensitivities to cadmium, which ultimately determines the fate of the cell. In this review, we provided a detailed survey of the current literature on autophagy in cadmium-induced tissue damage. A better understanding of the complex regulation of cell death by autophagy might contribute to the development of novel preventive and therapeutic strategies to treat acute and chronic cadmium toxicity.

Selenium Antagonizes Cadmium-Induced Inflammation and Oxidative Stress via Suppressing the Interplay between NLRP3 Inflammasome and HMGB1/NF-κB Pathway in Duck Hepatocytes

Cadmium (Cd) is a toxic heavy metal that can accumulate in the liver of animals, damaging liver function. Inflammation and oxidative stress are considered primary causes of Cd-induced liver damage. Selenium (Se) is an antioxidant and can resist the detrimental impacts of Cd on the liver. To elucidate the antagonism of Se on Cd against hepatocyte injury and its mechanism, duck embryo hepatocytes were treated with Cd (4 μM) and/or Se (0.4 μM) for 24 h. Then, the hepatocyte viability, oxidative stress and inflammatory status were assessed. The findings manifested that the accumulation of reactive oxygen species (ROS) and the levels of pro-inflammatory factors were elevated in the Cd group. Simultaneously, immunofluorescence staining revealed that the interaction between NOD-like receptor pyran domain containing 3 (NLRP3) and apoptosis-associated speck-like protein (ASC) was enhanced, the movement of high-mobility group box 1 (HMGB1) from nucleus to cytoplasm was increased and the inflammatory response was further amplified. Nevertheless, the addition of Se relieved the above-mentioned effects, thereby alleviating cellular oxidative stress and inflammation. Collectively, the results suggested that Se could mitigate Cd-stimulated oxidative stress and inflammation in hepatocytes, which might be correlated with the NLRP3 inflammasome and HMGB1/nuclear factor-κB (NF-κB) signaling pathway.