Hexavalent Chromium Causes Apoptosis and Autophagy by Inducing Mitochondrial Dysfunction and Oxidative Stress in Broiler Cardiomyocytes

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.

Cr(VI) induces ferroptosis in DF-1 cells by simultaneously perturbing iron homeostasis of ferritinophagy and mitophagy

Hexavalent chromium [Cr(VI)] is an environmental pollutant known for its strong oxidizing and carcinogenic effects. However, its potential to induce ferroptosis in poultry remains poorly understood. This study aims to investigate the induction of ferroptosis by Cr(VI) in DF-1 cells and elucidate the underlying mechanisms. DF-1 cells exposed to Cr(VI) showed increased lipid reactive oxygen species and changes in ferroptosis marker genes (decreased expression of GPX4 and increased expression of COX2). Notably, the addition of the ferroptosis-specific inhibitor ferrostatin-1 (Fer-1) can reverse this effect. During the cell death process, Cr(VI) induced ferritinophagy, disrupting iron homeostasis and releasing labile iron ions. We predicted by docking that these iron ions would bind to mitochondrial membrane proteins through virtual docking. This binding was validated through colocalization analysis. In addition, Cr(VI) caused mitophagy, which releases additional ferrous ions. Therefore, Cr(VI) can induce the simultaneous release of ferrous ions through these pathways, thereby exacerbating lipid peroxidation and ultimately triggering ferroptosis in DF-1 cells. This study demonstrates that Cr(VI) can induce ferroptosis in DF-1 cells by disrupting intracellular iron homeostasis and providing valuable insights into the toxic effects of Cr(VI) in poultry and potentially other organisms.

Asiatic Acid Alleviates Lipopolysaccharide-Induced Acute Myocardial Injury by Promoting Mitophagy and Regulating Mitochondrial Dynamics in Broilers

Acute myocardial injury (AMI) induced by lipopolysaccharide (LPS) can cause cardiovascular dysfunction and lead to death in poultry. Traditional antibiotic therapy has been found to have many limitations and negative effects. Asiatic acid (AA) is a naturally occurring pentacyclic triterpenoid that is extracted from Centella asiatica and has anti-inflammatory, antioxidant, and anticancer pharmacological properties. Previously, we studied the effect of AA on LPS-induced liver and kidney injury; however, the impact of AA on LPS-induced AMI remained unclear. Sixty 1-day-old broilers were randomly divided into control group, LPS group, LPS + AA 15 mg/kg group, LPS + AA 30 mg/kg group, LPS + AA 60 mg/kg group, and control + AA 60 mg/kg group. The histopathology of cardiac tissues was detected by hematoxylin and eosin (H&E) staining. The mRNA and protein expressions related to mitochondrial dynamics and mitophagy were detected by quantitative real-time PCR, western blot, immunofluorescence, and immunohistochemistry. Disorganized myocardial cells and fractured myocardial fibers were found in the LPS group, and obvious red-blood-cell filling can be seen in the gaps between the myocardial fibers in the low-dose AA group. Nevertheless, the medium and high dose of AA obviously attenuated these changes. Our results showed that AA significantly restored the mRNA and protein expressions related to mitochondrial dynamic through further promoting mitophagy. This study revealed the effect of AA on LPS-induced AMI in broilers. Mechanically, AA regulated mitochondrial dynamic homeostasis and further promoted mitophagy. These novel findings indicate that AA may be a potential drug for LPS-induced AMI in broilers.

Effects of hexavalent chromium on mitochondria and their implications in carcinogenesis

Hexavalent chromium (Cr(VI)) is a well-known occupational and environmental human carcinogen. The cellular effect of Cr(VI) is complex and often nonspecific due to its ability to modulate multiple cellular targets. The toxicity of Cr(VI) is strongly linked to the generation of reactive oxygen species (ROS) during its reduction process. ROS can cause oxidation of cellular macromolecules, such as proteins, lipids, and DNA, thereby altering their functions. A major genotoxic effect of Cr(VI) that contributes to carcinogenesis is the formation of DNA adducts, which can lead to DNA damage. Modulations of cellular signaling pathways and epigenetics may also contribute to the carcinogenic effects of Cr(VI). Cr(VI) has a major impact on many aspects of mitochondrial biology, including oxidative phosphorylation, mitophagy, and mitochondrial biogenesis. These effects have the potential to alter the trajectory of Cr(VI)-induced carcinogenic process. This perspective article summarizes current understandings of the effect of Cr(VI) on mitochondria and discusses the future directions of research in this area, particularly with regard to carcinogenesis.

Hexavalent chromium caused DNA damage repair and apoptosis via the PI3K/AKT/FOXO1 pathway triggered by oxidative stress in the lung of rat

Hexavalent chromium [Cr(VI)] is an occupational carcinogen that accumulates in the lungs and causes lung injury and even lung cancer. 36 SD male rats received inhalable intratracheal instillation of Cr(VI) (0.05, 0.25 mg Cr/kg) or the same volume (3 ml/kg) of normal saline weekly for 28 days (total 5 times). After 28 days of exposure, half of the rats in each group were sacrificed for investigation, and the rest stopped exposure and began to be self-repaired for two weeks. Histopathology analyses revealed that Cr(VI) induced slight dilatation and hemorrhage of perialveolar capillaries, pulmonary bronchodilation, and congestion with peripheral flaky-like necrosis accompanied by inflammatory cell infiltration, especially the 0.25 mg Cr/kg group. Cr(VI) exposure caused the increase of blood Cr, urinary Cr, MDA, urinary 8-hydroxy-2' -deoxyguanosine (8-OHdG), and the decrease of GSH and MDA, while two-week repair only reduced urinary Cr. Exposure to Cr(VI) significantly upregulated FOXO1 and downregulated p-AKT and p-FOXO1 for two weeks. PI3K in the 0.25 mg Cr/kg group was inhibited after two weeks of repair. Cr(VI) exposure mainly promoted GADD45a and CHK2 in the exposure group, promoted Bim, Bax/Bcl-2, and suppressed Bcl-2 and Bcl-xL in the repair group. These results demonstrate that Cr(VI) may induce DNA damage repair and apoptosis in the lung by activating the PI3K/AKT/FOXO1 pathway. Two-week repair may alleviate oxidative stress and DNA damage induced by Cr(VI) exposure but couldn't eliminate its effects. This study provides a new perspective for exploring the Cr(VI) induced lung cancer mechanism.

Contaminant Metals and Cardiovascular Health

A growing body of research has begun to link exposure to environmental contaminants, such as heavy metals, with a variety of negative health outcomes. In this paper, we sought to review the current research describing the impact of certain common contaminant metals on cardiovascular (CV) health. We reviewed ten metals: lead, barium, nickel, chromium, cadmium, arsenic, mercury, selenium, zinc, and copper. After a literature review, we briefly summarized the routes of environmental exposure, pathophysiological mechanisms, CV health impacts, and exposure prevention and/or mitigation strategies for each metal. The resulting article discloses a broad spectrum of pathological significance, from relatively benign substances with little to no described effects on CV health, such as chromium and selenium, to substances with a wide-ranging and relatively severe spectrum of CV pathologies, such as arsenic, cadmium, and lead. It is our hope that this article will provide clinicians with a practical overview of the impact of these common environmental contaminants on CV health as well as highlight areas that require further investigation to better understand how these metals impact the incidence and progression of CV diseases.

Preparation, characterization, and antioxidant and antiapoptotic activities of biosynthesized nano‑selenium by yak-derived Bacillus cereus and chitosan-encapsulated chemically synthesized nano‑selenium

Nano‑selenium (SeNPs) is a red elemental selenium with extremely small particles, which can be absorbed by the body and has biological activity. Currently, the most commonly used synthetic methods for SeNPs are biosynthesis and chemical synthesis. In this study, YC-3-SeNPs were biosynthesized by a strain of yak-gut Bacillus cereus YC-3, and meanwhile, CST-SeNPs were chemically synthesized and encapsulated with chitosan. A series of characterizations proved that YC-3-SeNPs and CST-SeNPs are spherical particles with excellent stability, and both have an excellent ability to scavenge free radicals in vitro. The particles of YC-3-SeNPs were encapsulated with polysaccharides, fiber, and protein, and it was less toxic than that of CST-SeNPs. Additionally, YC-3-SeNPs and CST-SeNPs may inhibit H₂O₂-induced oxidative stress in cardiomyocytes by activating the Keap1/Nrf2/HO-1 signaling pathway thereby scavenging ROS. Meanwhile, they may exert anti-apoptotic activity in cardiomyocytes by stabilizing mitochondrial membrane potential (∆Ψm) and balancing Bax/Bcl-2 protein, thereby reducing the protein expression of Cyt-c and Cleaved-caspase 3. Given the above, YC-3-SeNPs and CST-SeNPs with excellent antioxidant and anti-apoptotic activities may have broad application potential in the field of cardiovascular diseases.

COVID-19 mRNA Vaccines: The Molecular Basis of Some Adverse Events

Each injection of any known vaccine results in a strong expression of pro-inflammatory cytokines. This is the result of the innate immune system activation, without which no adaptive response to the injection of vaccines is possible. Unfortunately, the degree of inflammation produced by COVID-19 mRNA vaccines is variable, probably depending on genetic background and previous immune experiences, which through epigenetic modifications could have made the innate immune system of each individual tolerant or reactive to subsequent immune stimulations.We hypothesize that we can move from a limited pro-inflammatory condition to conditions of increasing expression of pro-inflammatory cytokines that can culminate in multisystem hyperinflammatory syndromes following COVID-19 mRNA vaccines (MIS-V). We have graphically represented this idea in a hypothetical inflammatory pyramid (IP) and we have correlated the time factor to the degree of inflammation produced after the injection of vaccines. Furthermore, we have placed the clinical manifestations within this hypothetical IP, correlating them to the degree of inflammation produced. Surprisingly, excluding the possible presence of an early MIS-V, the time factor and the complexity of clinical manifestations are correlated to the increasing degree of inflammation: symptoms, heart disease and syndromes (MIS-V).

Hexavalent-Chromium-Induced Oxidative Stress and the Protective Role of Antioxidants against Cellular Toxicity

Hexavalent chromium is a highly soluble environmental contaminant. It is a widespread anthropogenic chromium species that is 100 times more toxic than trivalent chromium. Leather, chrome plating, coal mining and paint industries are the major sources of hexavalent chromium in water. Hexavalent chromium is widely recognised as a carcinogen and mutagen in humans and other animals. It is also responsible for multiorgan damage, such as kidney damage, liver failure, heart failure, skin disease and lung dysfunction. The fate of the toxicity of hexavalent chromium depends on its oxidation state. The reduction of Cr (VI) to Cr (III) is responsible for the generation of reactive oxygen species (ROS) and chromium intermediate species, such as Cr (V) and Cr (IV). Reactive oxygen species (ROS) are responsible for oxidative tissue damage and the disruption of cell organelles, such as mitochondria, DNA, RNA and protein molecules. Cr (VI)-induced oxidative stress can be neutralised by the antioxidant system in human and animal cells. In this review, the authors summarise the Cr (VI) source, toxicity and antioxidant defence mechanism against Cr (VI)-induced reactive oxygen species (ROS).

Effects of Foliar Application of Nano-molybdenum Fertilizer on Copper Metabolism of Grazing Chinese Merino Sheep (Junken Type) on Natural Grasslands Under Copper and Cadmium Stress

In recent decades, the groundwater contaminated by mineral development and metal smelting has seriously polluted natural grasslands, resulting in heavy metal residues in soils and forages exceeding the standard, especially copper (Cu) and cadmium (Cd). After animals intake contaminated forages, heavy metals may accumulate in animal tissues and threaten human health through the food chain. Previous studies found that molybdenum (Mo) fertilizer from ammonium molybdate or potassium molybdate could alleviate the decrease of antioxidant capacity caused by heavy metal poisoning, but the application of nano-Mo fertilizer in sheep is still lacking. To investigate the effects of nano-Mo fertilizer on Cu metabolism of grazing Chinese Merino sheep (Junken Type) on natural pastures under Cu and Cd stress, fertilizing experiment was carried out in the Bayanbulak Grassland in the northwest of Xinjiang Uygur Autonomous Region, China. A total of 24 hm² fenced grassland contaminated by heavy metals was randomly divided into four groups (3 replications/group and 2 hm²/replication). The experimental groups were applied 0 g Mo, 100 g Mo, 200 g Mo, and 300 g Mo per hectare for the control group, group I, group II, and group III, respectively, through foliar spraying fertilization. A total of 72 Chinese Merino sheep (1 year old, 43.8 ± 2.3 kg) grazing on polluted natural grasslands, with 18 sheep per group, were randomly assigned to the experimental pastures for 30 days. The results showed that the Mo content in soil in group II and group III nwas higher than that in the control group (P < 0.05); the Cd content in soil in group II and group III was lower than that in the control group (P < 0.05), and the Cu content in soil in fertilized pastures was lower than that in the control group (P < 0.05). The Mo content in herbage in fertilized pastures was higher than that in the control group (P < 0.05), and the content of Cu in herbage in fertilized pastures was lower than that in the control group (P < 0.05). The contents of iron (Fe) and Mo in blood and liver of grazing animals from fertilized pastures were higher than that in the control group (P < 0.05). The Cd content in blood of grazing animals in group II and group III was lower than that in the control group (P < 0.05). The Cu content in blood and liver of grazing animals in fertilized pastures was lower than that in the control group (P < 0.05). The content of selenium (Se) in blood of grazing animals in group II and group III was higher than that in the control group (P < 0.05). The levels of blood including hemoglobin (Hb), erythrocyte count (RBC), and packed cell volume (PCV) in group II and group III were higher than that in the control group (P < 0.05). The white blood cell (RBC) count in group II and group III was lower than that in the control group (P < 0.05). The activities of serum superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), catalase (CAT), and ceruloplasmin (Cp) in group II and group III were higher than that in the control group (P < 0.05). The content of malondialdehyde (MDA) in group II and group III was lower than that in the control group (P < 0.05). In conclusion, the application of nano-Mo fertilizer on Cu- and Cd-contaminated grasslands changed the contents of mineral elements in soil, forage, and blood of grazing sheep, improved the antioxidant capacity, affected the Cu metabolism of grazing Chinese Merino sheep caused by Cu and Cd pollutions, and alleviated the toxic damage of heavy metal pollutions.