Protective effect of quercetin on cadmium-induced kidney apoptosis in rats based on PERK signaling pathway

Syzygium cumini Fruit Extract and Quercetin Ameliorate Cadmium-Induced Ovarian Apoptosis in Rats Via miRNA- 204 - 5p-Mediated Bcl- 2 Upregulation and Bax/Caspase 9/Caspase 3 Downregulation

The correlation between exposure to environmental pollutants and adverse impacts on fertility has been documented. Cadmium (Cd) is one of the most toxic elements that impairs female reproductive capacity. Syzygium cumini is a plant that contains polyphenols with strong antioxidant properties. Our study aimed to investigate the possible protective effects of Syzygium cumini fruit extract (SCFE) and quercetin (QU) against Cd-induced ovarian toxicity and apoptosis in rats assisted by measuring oxidative stress markers, hormonal profile, intrinsic apoptotic pathway, miRNA-204-5p, and histopathology. For that, 45 adult female rats were divided randomly into five groups; control, cadmium chloride (CdCl2), CdCl2 + QU, CdCl2 + SCFE200, and CdCl2 + SCFE400, and the experiment lasted 35 days. Cadmium exposure induced irregular estrus cycle, and oxidative challenges, as evidenced by increased malondialdehyde and decreased antioxidant indicators that include superoxide dismutase, catalase and reduced glutathione, and hormonal imbalances, including reduced follicle-stimulating hormone, luteinizing hormone, anti-mullarian hormone, estrogen, and progesterone levels. Additionally, Cd triggered ovarian apoptosis through upregulating miRNA- 204 - 5p expression that in turn downregulated Bcl- 2 and upregulated the members of intrinsic mitochondrial apoptotic pathway including Bax and caspases 3, 9. The histopathological findings, morphometric and lesion scoring in ovarian, and uterine tissues confirmed the negative impacts of Cd. Interestingly, treatment with QU or SCFE, especially at the higher dose (400 mg/kg), significantly ameliorated these Cd-induced adverse effects, suggesting their potential as protective agents against ovarian toxicity.

New insights into heavy metal cadmium-induced liver injury: Prominent role of programmed cell death mechanisms

The heavy metal cadmium (Cd) is an important environmental factor that induces liver injury and contributes to liver disease. Ongoing research aims to refine our understanding of the pathogenesis of cadmium-induced liver injury and the interactions between the various mechanisms. Oxidative stress, described as a pathophysiological basis of liver injury, is a process in which reactive oxygen species are generated, causing the destruction of hepatocyte structure and cellular dysfunction. Additionally, the activation of oxidative stress downstream signals regulates several forms of cell death, such as apoptosis, necroptosis, autophagy, ferroptosis, and pyroptosis, which significantly contributes to liver damage. Furthermore, the interplay between different types of programmed cell death highlights the complexity of liver injury mechanisms. This review summarizes the role of programmed cell death in Cd-induced liver injury and explores the relationships between different programmed cell death pathways, which is expected to provide new insights into the mechanisms of Cd-induced liver injury.

Cadmium disrupted homeostasis of proximal renal tubular cells via targeting ATF4-CHOP complex into the nucleus

Cadmium, a ubiquitous toxic metal and environmental pollutant, is associated with several renal metabolic disorders and disrupts the homeostasis of kidneys in humans and animals. However, the precise molecular mechanism remains poorly elucidated. The present study investigated the role of the ATF4-CHOP nuclear transcriptional axis and its interactions with cellular pathways in cadmium-induced nephrotoxicity. We acquired 120 one-day-old chickens, randomly divided them into four groups (Con, Cd35, Cd70, Cd140), and were treated with graded cadmium doses for 90 days. The kidney tissues were collected for comprehensive histopathological, biochemical, and molecular analyses using western blotting, qRT-PCR, immunofluorescence, and tunel assay. Subsequently, we revealed that cadmium exposure induced ER stress, significantly upregulated CHOP expression, and activated pro-apoptotic ATF4-CHOP axis. Our findings revealed a complex interplay, where ER stress activated inflammation. Concurrently, mitochondrial disruption elevated ROS production and oxidative stress, which impaired renal homeostasis. Moreover, inhibition of autophagy and mitophagy led to the accumulation of damaged cell organelles, further exacerbating apoptotic signaling. Our results elucidate that an integrated network of cellular stress pathways mediates cadmium-induced renal toxicity, with the ATF4-CHOP axis acting as a crucial pro-apoptotic pathway. This study provides critical insights into the mechanisms of cadmium-induced nephrotoxicity and potential therapeutic interventions to mitigate heavy metal-induced renal homeostasis disruption and renal damage.

Swimming Into View: Zebrafish Uncover Targets, Mechanisms, and Therapies for Cadmium Toxicity

PURPOSE OF REVIEW

Cadmium (Cd) remains a persistent threat to human and environmental health. To better understand causal relationships between genotype and disease phenotypes, a genetically tractable model, zebrafish (Danio rerio) has emerged. We summarize recent empirical evidence on the targets, mechanisms, and potential therapies for Cd toxicity.

RECENT FINDINGS

Recent results show that waterborne Cd exhibits organ specific accumulation including in the eye, brain, heart, and gonads triggering oxidative stress, inflammation, gut dysbiosis, and altered methylation patterns that persist across generations. Novel mechanisms of Cd toxicity include the gut-brain axis, ionic antagonism, the Wnt/β-catenin pathway, and epigenetics, leading to potential therapeutics such as probiotics, selenium, and antioxidants. Based on the reviewed literature, more studies should examine the effects of dietary Cd on zebrafish behavior, brains, and cardiovascular function. Given that humans and wildlife are chronically exposed to Cd, leading to gonadal Cd accumulation, studies should conduct early-life exposures across the zebrafish lifespan and assess endpoints across generations to capture germline and epigenetic effects and mechanisms. The zebrafish's biomedical toolkit, along with high-content screening, should be utilized to develop and refine therapies.

Cadmium-Induced Kidney Apoptosis Based on the IRE1α-XBP1 Signaling Pathway and the Protective Effect of Quercetin

Cadmium (Cd) is an important environmental pollutant that can enter the body and inflict kidney damage. Quercetin (Que) is a natural flavonoid compound that can alleviate kidney damage in Cd-treated rats, but the specific mechanism is unclear. Herein, 24 male Sprague-Dawley rats were divided into four groups, namely the control, Cd, Cd + Que, and Que groups. Four weeks later, the rats were anesthetized with ether and were euthanized; then, their blood was collected and their kidneys were removed. Renal function markers were measured. Kidney tissue structure was observed by HE staining, cell apoptosis was detected by the TUNEL method, and mRNA and protein expression levels in the IRE1α-XBP1 apoptosis signaling pathway were analyzed by RT-PCR and Western blotting. Results showed that the Cd treatment group exhibited decreased renal dysfunction and pathologic injury. Cd-induced tissue damage and cell apoptosis and significantly increased the mRNA and protein expression levels (p < 0.01) related to the IRE1α-XBP1 signaling pathway. Compared with the Cd group, the Cd + Que group exhibited increased renal dysfunction. Conversely, kidney tissue damage and renal cell apoptosis decreased, and the mRNA and protein expression levels of IRE1α and XBP1 significantly decreased (p < 0.01). Cd treatment inflicted renal damage. Therefore, Que can restore the kidney tissue damage and alleviate the cell apoptosis caused by Cd through the inhibition of the IRE1α-XBP1 signaling pathway.

Linalool may have a therapeutic effect on cadmium-induced nephrotoxicity by regulating NF-κB/TNF and GRP78/CHOP signaling pathways

Cadmium (Cd) is an environmental pollutant heavy metal with nephrotoxic effect. One of the primary constituents of essential oils is Linalool (Lin), a monoterpene having a variety of pharmacological properties including antimicrobial, anti-inflammatory, and antioxidant effects. The purpose of this study was to ascertain how Lin affected endoplasmic reticulum stress (ERS) and pro-inflammatory mediators in Cd-induced nephrotoxicity. In the experiment, 28 male rats were randomly divided into four equal groups as control (no application), Cd (Cd at a dose of 3 mg/kg for the first 7 days), Cd+Lin (Cd at a dose of 3 mg/kg for the first 7 days and 100 mg/kg/day Lin) and Lin (100 mg/kg/day Lin) (n=7). The experiment was completed on the 15th day after all treatments were performed. Blood serum and kidney tissue samples were used for analyses. Cd-induced histopathological changes, inflammation, oxidative stress, and apoptosis were determined to increase in kidney tissue. However, it was observed that Cd-induced adverse effects in kidney tissue were mainly eliminated by Lin treatment. In conclusion, Lin demonstrated anti-inflammatory, anti-oxidant and anti-apoptotic effects in Cd-induced nephrotoxicity. Therefore, we believe that Lin may represent a high potential therapeutic strategy against renal tissue damage.

Calcium signaling crosstalk between the endoplasmic reticulum and mitochondria, a new drug development strategies of kidney diseases

Calcium (Ca2+) acts as a second messenger and constitutes a complex and large information exchange system between the endoplasmic reticulum (ER) and mitochondria; this process is involved in various life activities, such as energy metabolism, cell proliferation and apoptosis. Increasing evidence has suggested that alterations in Ca2+ crosstalk between the ER and mitochondria, including alterations in ER and mitochondrial Ca2+ channels and related Ca2+ regulatory proteins, such as sarco/endoplasmic reticulum Ca2+-ATPase (SERCA), inositol 1,4,5-trisphosphate receptor (IP3R), and calnexin (CNX), are closely associated with the development of kidney disease. Therapies targeting intracellular Ca2+ signaling have emerged as an emerging field in the treatment of renal diseases. In this review, we focused on recent advances in Ca2+ signaling, ER and mitochondrial Ca2+ monitoring methods and Ca2+ homeostasis in the development of renal diseases and sought to identify new targets and insights for the treatment of renal diseases by targeting Ca2+ channels or related Ca2+ regulatory proteins.