Alleviation of Lead-Induced Apoptosis by Puerarin via Inhibiting Mitochondrial Permeability Transition Pore Opening in Primary Cultures of Rat Proximal Tubular Cells

Lead Isolation and Capture in Perovskite Photovoltaics toward Eco-Friendly Commercialization

Perovskite solar cells (PSCs) are developed rapidly in efficiency and stability in recent years, which can compete with silicon solar cells. However, an important obstacle to the commercialization of PSCs is the toxicity of lead ions (Pb2+) from water-soluble perovskites. The entry of free Pb2+ into organisms can cause severe harm to humans, such as blood lead poisoning, organ failure, etc. Therefore, this work reports a "lead isolation-capture" dual detoxification strategy with calcium disodium edetate (EDTA Na-Ca), which can inhibit lead leakage from PSCs under extreme conditions. More importantly, leaked lead exists in a nontoxic aggregation state chelated by EDTA. For the first time, in vivo experiments are conducted in mice to systematically prove that this material has a significant inhibitory effect on the toxicity of perovskites. In addition, this strategy can further enhance device performance, enabling the optimized devices to achieve an impressive power conversion efficiency (PCE) of 25.19%. This innovative strategy is a major breakthrough in the research on the prevention of lead toxicity in PSCs.

Puerarin Prevents Cadmium-Induced Neuronal Injury by Alleviating Autophagic Dysfunction in Rat Cerebral Cortical Neurons

Autophagic dysfunction is one of the main mechanisms of cadmium (Cd)-induced neurotoxicity. Puerarin (Pue) is a natural antioxidant extracted from the medicinal and edible homologous plant Pueraria lobata. Studies have shown that Pue has neuroprotective effects in a variety of brain injuries, including Cd-induced neuronal injury. However, the role of Pue in the regulation of autophagy to alleviate Cd-induced injury in rat cerebral cortical neurons remains unclear. This study aimed to elucidate the protective mechanism of Pue in alleviating Cd-induced injury in rat cerebral cortical neurons by targeting autophagy. Our results showed that Pue alleviated Cd-induced injury in rat cerebral cortical neurons in vitro and in vivo. Pue activates autophagy and alleviates Cd-induced autophagic blockade in rat cerebral cortical neurons. Further studies have shown that Pue alleviates the Cd-induced inhibition of autophagosome-lysosome fusion, as well as the inhibition of lysosomal degradation. The specific mechanism is related to Pue alleviating the inhibition of Cd on the expression levels of the key proteins Rab7, VPS41, and SNAP29, which regulate autophagosome-lysosome fusion, as well as the lysosome-related proteins LAMP2, CTSB, and CTSD. In summary, these results indicate that Pue alleviates Cd-induced autophagic dysfunction in rat cerebral cortical neurons by alleviating autophagosome-lysosome fusion dysfunction and lysosomal degradation dysfunction, thereby alleviating Cd-induced neuronal injury.

The Mitochondrion: A Promising Target for Kidney Disease

Mitochondrial dysfunction is important in the pathogenesis of various kidney diseases and the mitochondria potentially serve as therapeutic targets necessitating further investigation. Alterations in mitochondrial biogenesis, imbalance between fusion and fission processes leading to mitochondrial fragmentation, oxidative stress, release of cytochrome c and mitochondrial DNA resulting in apoptosis, mitophagy, and defects in energy metabolism are the key pathophysiological mechanisms underlying the role of mitochondrial dysfunction in kidney diseases. Currently, various strategies target the mitochondria to improve kidney function and kidney treatment. The agents used in these strategies can be classified as biogenesis activators, fission inhibitors, antioxidants, mPTP inhibitors, and agents which enhance mitophagy and cardiolipin-protective drugs. Several glucose-lowering drugs, such as glucagon-like peptide-1 receptor agonists (GLP-1-RA) and sodium glucose co-transporter-2 (SGLT-2) inhibitors are also known to have influences on these mechanisms. In this review, we delineate the role of mitochondrial dysfunction in kidney disease, the current mitochondria-targeting treatment options affecting the kidneys and the future role of mitochondria in kidney pathology.

Puerarin prevents cadmium-induced mitochondrial fission in AML-12 cells via Sirt1-dependent pathway

Recent investigations have revealed that puerarin (PU) alleviates cadmium (Cd)-caused hepatic damage via inhibiting oxidative stress. Mitochondria are dynamic organelles and play a critical part in regulating the occurrence of oxidative stress, but the role of mitochondria in the protection of PU against hepatocellular damage caused by Cd exposure remains unknown. Thus, this study was aimed to clarify this issue using mouse hepatocyte AML-12 cell line. Transmission electron microscopy analysis firstly showed that PU prevents Cd-induced mitochondrial ultrastructure damage. Mitochondrial network image analysis by confocal microscopy revealed that PU exerts the protection against Cd-induced cytotoxicity via restoring mitochondrial network fragmentation. Also, mitochondrial dynamic protein expression profiles showed that enhanced fission protein levels and inhibited fusion protein levels in Cd-treated cells were significantly reversed by PU, suggesting the protective effect of PU against Cd-induced mitochondrial fission. Moreover, changes of intracellular ATP level and protein levels of key regulators involving in mitochondrial biogenesis indicated that Sirtuin-1(Sirt1) pathway may be involved in the protection of Cd-impaired mitochondrial function by PU. Next, Sirt1 protein levels in treated cells were effectively regulated by genetic knockdown or chemical agonist SRT1720. Accordingly, alleviation of Cd-induced mitochondrial fission assays and cell viability by PU was markedly regulated by SRT1720 or Sirt1 knockdown, suggesting the indispensable role of Sirt1 in this process. Collectively, these findings highlight that PU prevents Cd-induced mitochondrial fission to alleviate cytotoxicity via Sirt1-dependent pathway, which provide novel evidences to fully understand the hepatoprotective action of PU against heavy metal toxicity.

Glyphosate-induced mitochondrial reactive oxygen species overproduction activates parkin-dependent mitophagy to inhibit testosterone synthesis in mouse leydig cells

Glyphosate (GLY), one of the most extensively used herbicides in the world, has been shown to inhibit testosterone synthesis in male animals. Mitochondria are crucial organelles for testosterone synthesis and its dysfunction has been demonstrated to induce the inhibition of testosterone biosynthesis. However, whether low-dose GLY exposure targets mitochondria to inhibit testosterone synthesis and its underlying mechanism remains unclear. Here, an in vitro model of 10 μM GLY-exposed mouse Leydig (TM3) cells was established to elucidate this issue. Data firstly showed that mitochondrial malfunction, mainly manifested by ultrastructure damage, disturbance of mitochondrial dynamics and mitochondrial reactive oxygen species (mtROS) overproduction, was responsible for GLY-decreased protein levels of steroidogenic enzymes, which leads to the inhibition of testosterone synthesis. Enhancement of autophagic flux and activation of mitophagy were shown in GLY-treated TM3 cells, and further studies have revealed that GLY-activated mitophagy is parkin-dependent. Notably, GLY-inhibited testosterone production was significantly improved by parkin knockdown. Finally, data showed that treatment with mitochondria-targeted antioxidant Mito-TEMPO (M-T) markedly reversed GLY-induced mitochondrial network fragmentation, activation of parkin-dependent mitophagy and consultant testosterone reduction. Overall, these findings demonstrate that GLY induces mtROS overproduction to activate parkin-dependent mitophagy, which contributes to the inhibition of testosterone synthesis. This study provides a potential mechanistic explanation for how GLY inhibits testosterone synthesis in mouse Leydig cells.

Puerarin mitigates oxidative injuries, opening of mitochondrial permeability transition pores and pathological damage associated with liver and kidney in Xanthium strumarium-intoxicated rats

In this study, the therapeutic effects of puerarin on Xanthium strumarium toxicity, which can develop in many species and does not have a specific antidote, were investigated. A single dose of 100 g/kg X. strumarium seeds was administered by gavage to female Sprague-Dawley rats, 6 h following which 200 mg/kg puerarin was administered by the same route, with puerarin administration being repeated daily at the same time. After completing the application, the blood, liver and kidney tissues of the rats were examined. Further, the biochemical parameters, glucose, MDA, GSH, SOD, mitochondrial Ca²⁺ and mitochondrial permeability transition pore (mPTP) opening levels, apoptotic factors (TUNEL, Bax and Bcl-2), ATP synthase and histopathological changes of the experimental rats were examined. The results revealed that while the administration of X. strumarium resulted in increased blood AST, ALT, ALP, LDH, CK, BUN and creatinine levels, it decreased glucose levels. In addition, it increased the MDA levels in the tissues and significantly increased the oxidative stress levels by decreasing the GSH levels and SOD activity. X. strumarium caused an increase in the mitochondrial Ca²⁺ and mPTP opening levels. Moreover, it increased the immunohistochemically determined ATP synthase expression and histopathologically identified necrotic liver cell death rates. Owing to its antioxidant properties and inhibitory effects on mPTP opening, puerarin administered for therapeutic purposes decreased the oxidative damage caused by X. strumarium toxicity, blood biochemical parameter levels, mitochondrial Ca²⁺ levels, mPTP opening, ATP synthase expression and the percentage of necrotic cells. Hence, the reduction in the liver and kidney damage in X. strumarium toxicity by puerarin indicates its potential use as an antidote for X. strumarium poisoning.

Study on the Efficacy and Mechanism of Lycium barbarum Polysaccharide against Lead-Induced Renal Injury in Mice

Lead is one of the most common heavy metal pollutants in the environment. Prolonged exposure to lead will induce oxidative stress, inflammation, and apoptosis in the kidneys, which in turn causes kidney injury. Lycium barbarum polysaccharide (LBP) is well known for its numerous pharmacological properties. This study aims to explore the efficacy and mechanism of LBP against lead-induced kidney damage in mice. Symptoms of renal injury were induced in mice by using 25 mg/kg lead acetate (PbAc₂), and different doses of LBP (200, 400, and 600 mg/kg BW) were orally administrated to PbAc₂-treated mice for five weeks. The results of the pharmacodynamics experiment showed that the renal pathological damages, serum creatinine (Cre), blood urea nitrogen (BUN), and kidney index of PbAc₂-treated mice could be significantly alleviated by treatment with LBP. Further, LBP treatment significantly increased the weight and feed intake of PbAc₂-treated mice. The dose effect results indicated that a medium dose of LBP was superior to high and low doses. The results of mechanistic experiments showed that LBP could attenuate oxidative stress, inflammation, and apoptosis in the kidneys of mice with lead toxicity by activating the nuclear factor erythroid 2-related factor 2 (Nrf2) signaling pathway.

Lycopene antagonizes lead toxicity by reducing mitochondrial oxidative damage and mitochondria-mediated apoptosis in cultured hippocampal neurons

Lead (Pb) exhibits serious adverse effects on the central nervous system, and the major pathogenic mechanism of Pb toxicity is oxidative stress. As one of the carotenoid family members with potent antioxidant properties, lycopene has shown its protections by inhibiting oxidative stress damage in numerous models of neurotoxicity. The current study was designed to explore the possible protective property in primary cultured rat hippocampal neurons challenged with Pb. We observed that 5 μM lycopene pretreatment for 4 h efficiently ameliorated Pb‐caused damage in cell viability, accumulation of reactive oxygen species (ROS), and apoptosis in a dose‐dependent manner. Moreover, lycopene (5 μM) attenuated the 50 μM Pb‐induced mitochondrial ROS production, improved the activities of mitochondrial respiratory chain enzymes and ATP production, and ameliorated the 50 μM Pb‐induced depolarization of mitochondrial membrane potential as well as opening of mitochondrial permeability transition pores. In addition, 5 μM lycopene restored the imbalance of Bax/Bcl‐2, inhibited translocation of cytochrome c, and reduced caspase‐3 activation. Taken together, these findings indicate that lycopene antagonizes against Pb‐induced neurotoxicity and the underlying mechanism probably involves reduction of mitochondrial oxidative damage and mitochondria‐mediated apoptosis.

Drp1/Mff signaling pathway is involved in fluoride-induced abnormal fission of hepatocyte mitochondria in mice

Fluoride, a toxic substance, is widely distributed in the environment and causes serious damage to the body. This study was performed to investigate the effects of fluoride on mitochondrial fission in mouse hepatocytes. A total of 48 mice were equally divided into four groups and admisnistered with NaF in drinking water at fluorine ion concentrations of 0, 25, 50 and 100 mg/L for 70 days. The pathomorphology and ultrastructurre of hepatocytes were then observed. The mitochondrial lesion parameters (number, length, width and vacuolization area) are evaluated. The expression of Drp1, Mff, Fis1, MiD49, MiD51 and Dyn2, which are associated with mitochondrial fission, was determined by quantitative real-time PCR and Western blot analysis. Apoptosis was detected by using TUNEL assay. Results showed that fluoride causes notable changes in the pathological morphology of liver tissues and severely damages the ultrastructure of hepatocytes. Damage manifested as nuclear condensation, nuclear membrane breakdown, mitochondrial vacuolation, increased fragmentation, and mitochondrial fission. Moreover, mRNA and protein expression levels were significantly upregulated in the Drp1/Mff signaling pathway. The mRNA expression levels of Cyt c, caspase 9 and 3 markedly increased in the fluoride treated groups in a dose-dependent manner. The percentage of TUNEL-positive nuclei in the liver remarkably increased after fluoride treatment. Overall, the results indicate that excessive fluoride exposure can increase mitochondrial fission via the Drp1/Mff signaling pathway, severely damage the mitochondrial structure, and lead to apoptosis of hepatocytes.

Simultaneous quantitation of glycyrrhetic acid and puerarin in plasma using ultra flow liquid chromatography tandem mass spectrometry and application in a pharmacokinetics study in healthy and alcoholic liver injury rats

A rapid, sensitive, and accurate ultra flow liquid chromatography tandem mass spectrometry (UFLC-MS/MS ) method was developed and validated for simultaneous quantitation of glycyrrhetic acid and puerarin in plasma derived from healthy and alcoholic liver injury rats. Plasma samples from healthy and model rats were deproteinated with methanol using liquiritin as an internal standard. Chromatography separation was performed by a Waters BEH (ethylene-bridged hybrid) C₁₈ column (2.1 × 50 mm; 1.7 μm) using a gradient elution from acetonitrile and water (containing 0.1% formic acid) and at a flow rate of 0.4 mL/min. Quantitation was performed on a Triple Quad 4500 tandem mass spectrometer coupled with an electrospray ionization source in negative multiple reaction monitoring mode. Specificity, carryover, dilution integrity, recovery, linearity, precision and accuracy, matrix effect, and stability were within acceptable limits. The newly established method was successfully applied to a pharmacokinetics study to investigate glycyrrhetic acid and puerarin in healthy and alcoholic liver injury rats.

Luteolin protects against lead acetate-induced nephrotoxicity through antioxidant, anti-inflammatory, anti-apoptotic, and Nrf2/HO-1 signaling pathways

Lead (Pb) is one of the most common heavy metal pollutants affecting living organisms. It induces nephrotoxicity with significant alterations in renal structure and function. Luteolin (LUT) a flavonoid present in various plant products is well known for exhibiting numerous pharmacological properties. We evaluated the protective efficacy of LUT against Pb-induced renal injury in male Wistar rats. Four experimental groups: control, LUT (50 mg/kg, orally), PbAc (20 mg/kg, i.p.), LUT + PbAc (at the aforementioned doses) were maintained for 7 days. PbAc administration significantly increased renal Pb accumulation, urea, and creatinine levels in serum, and induced renal histological alterations. Additionally, compared to the control rats, PbAc-treated rats exhibited significantly low levels of antioxidant enzyme activity and expression (SOD, CAT, GPx and GR), as well as high MDA levels. Moreover, PbAc exposure downregulated Nfe212 and Homx1 mRNA expression and significantly increased inflammatory marker (TNF-α, IL-1β and NO) levels in renal tissue. PbAc significantly upregulated the synthesis of apoptotic related proteins and downregulated antiapoptotic protein expression. Notably, LUT pretreatment of PbAc-treated rats provided significant nephroprotection and reversed the alterations in the abovementioned parameters. In conclusion, LUT provided significant protection against PbAc intoxication via antioxidant, anti-inflammatory, and anti-apoptotic activities by activating the Nrf2/ARE signaling pathway.

Lead (Pb) induced ATM-dependent mitophagy via PINK1/Parkin pathway

Lead (Pb), a widely distributed environmental pollutant, is known to induce mitochondrial damage as well as autophagy in vitro and in vivo. In this study, we found that Pb could trigger mitophagy in both HEK293 cells and the kidney cortex of male Kunming mice. However, whether ataxia telangiectasis mutated (ATM) which is reported to be linked with PTEN-induced putative kinase 1 (PINK1)/Parkin pathway (a well-characterized mitophagic pathway) participates in the regulation of Pb-induced mitophagy and its exact role remains enigmatic. Our results indicated that Pb activated ATM in vitro and in vivo, and further in vitro studies showed that ATM could co-localize with PINK1 and Parkin in cytosol and interact with PINK1. Knockdown of ATM by siRNA blocked Pb-induced mitophagy even under the circumstance of enhanced accumulation of PINK1 and mitochondrial Parkin. Intriguingly, elevation instead of reduction in phosphorylation level of PINK1 and Parkin was observed in response to ATM knockdown and Pb did not contribute to the further increase of their phosphorylation level, implying that ATM indirectly regulated PINK1/Parkin pathway. These findings reveal a novel mechanism for Pb toxicity and suggest the regulatory importance of ATM in PINK1/Parkin-mediated mitophagy.

Silencing of astrocyte elevated gene-1 inhibits proliferation and migration of melanoma cells and induces apoptosis

Melanoma is an aggressive skin malignancy with a high mortality. Astrocyte elevated gene-1 (AEG-1), a downstream target of Ras and c-Myc, has been implicated in the development of multiple tumours, but its role in melanoma remains unclear. In the present study, the role of AEG-1 in melanoma was explored through AEG-1 silencing. Our results showed that silencing AEG-1 inhibited the proliferation of melanoma cells, induced cell cycle arrest, and reduced levels of cyclin A, cyclin B, cyclin D1, cyclin E, and cyclin-dependent kinase 2. AEG-1silencing also induced apoptosis in melanoma cells and altered the levels of cleaved caspase-3, B-cell lymphoma-2 (Bcl-2) and Bcl-2 associated X protein. Moreover, silencing AEG-1 suppressed the migration and invasion of melanoma cells, reduced the expressions and activities of matrix metallopeptidase (MMP)-2 and MMP-9, and inhibited the activation of the Wnt/β-catenin signalling pathway in melanoma cells. Furthermore, in vivo experiments revealed that AEG-1 silencing inhibited the growth of melanoma xenografts in nude mice. In summary, our study demonstrates an oncogenic role of AEG-1 in melanoma and suggests that AEG-1 may serve as a potential therapeutic target in the treatment of melanoma.

Puerarin attenuates diabetic kidney injury through the suppression of NOX4 expression in podocytes

Radix puerariae, a traditional Chinese herbal medication, has been used to treat patients with diabetic nephropathy (DN). Several studies demonstrated that puerarin, the active compound of radix puerariae, reduces diabetic injury in streptozotocin (STZ)-induced diabetic rodent models. However, as STZ injection alone results in mild kidney injury, the therapeutic benefit afforded by puerarin in DN remained inconclusive. Thus we sought to clarify the role of puerarin by employing an accelerated DN model, STZ-induced diabetes in the endothelial nitric oxide synthase-null (eNOS-/-) mice. Puerarin treatment of diabetic eNOS-/- mice significantly attenuated albuminuria and diabetic kidney injury, which were associated with reduced oxidative stress and reduced NAPDH oxidase 4 (NOX4) in glomeruli of diabetic eNOS-/- mice. Puerarin treatment of murine podocytes culture in high glucose conditions led to reduced superoxide production and NOX4 expression. We further determined that that puerarin treatment increased both mRNA and protein levels of SIRT1 in podocytes and that puerarin led to SIRT1-mediated deacetylation of NF-κB and suppression of NOX4 expression. Our findings confirm the renoprotective effects of puerarin in an experimental model of advanced DN and provide a molecular mechanism by which puerarin exerts the anti-oxidative effects in podocytes  in the diabetic milieu.

Anti-apoptotic role of spermine against lead and/or gamma irradiation-induced hepatotoxicity in male rats

Exposure to either lead (Pb) or γ-irradiation (IR) results in oxidative stress in biological systems. Herein, we explored the potential anti-apoptotic effect of spermine (Spm) against lead and/or γ-irradiation-induced hepatotoxicity in male albino rats. Rats were divided into eight experimental groups of ten rats each: groups including negative control, whole body γ-irradiated (6 Gray (Gy)), lead acetate (PbAct) trihydrate orally administered (75 mg/kg bw ≡ 40 mg/kg bw Pb for 14 consecutive days), and Spm intraperitoneally dosed (10 mg/kg bw for 14 consecutive days) rats and groups subjected to combinations of Pb + IR, Spm + IR, Spm + Pb, and Spm + Pb followed by IR on day 14 (Spm + Pb + IR). A significant decrease in arginase activity as well as mRNA and protein levels of Bcl-2 and p21 was observed in rats intoxicated with Pb and/or γ-irradiation compared to controls, whereas Bax mRNA and protein levels were significantly increased. Also, an increased level of nitric oxide (NO) with a reduced arginase activity was observed in liver tissues of intoxicated rats. Spm co-treatment with lead and/or γ-irradiation attenuated the increase in Bax mRNA and protein expression, while it restored those of Bcl-2 and p21 together with NO levels and arginase activity to control values. Altogether, we suggest that Spm may be useful in combating free radical-induced apoptosis in Pb-intoxicated and/or γ-irradiated rats.

The antagonistic effect of selenium on lead-induced apoptosis via mitochondrial dynamics pathway in the chicken kidney

Selenium (Se) is known to have antagonistic effects against lead (Pb) toxicity in animal. The aim of this study was to evaluate the roles of mitochondrial dynamics on Pb-induced apoptosis in the chicken kidney and investigate the antagonistic effect of Se. In the present study, brown layer chickens were randomly allocated to four groups, and each group were exposed to a basic diet (0.2 mg kg^-1 Se and 0.5 mg kg^-1 Pb), a Se-adequate diet (1 mg kg^-1 Se and 0.5 mg kg^-1 Pb), a Se and Pb compound diet (1 mg kg^-1 Se and 350 mg kg^-1 Pb) or a Pb supplemented diet (0.2 mg kg^-1 Se and 350 mg kg^-1 Pb). On the 90^th day, the kidney was removed to determine the activities of mitochondrial respiratory chain complexes, ATPases and oxidative indexes. The expression levels of mitochondrial dynamics and apoptosis-related genes were also determined. The results showed that Pb treatment significantly decreased the activities of mitochondrial complexes and ATPases, and increased oxidative stress, and mitochondrial dynamics and anti-apoptosis-related genes had a lower expression, whereas mitochondrial pro-apoptosis related genes presented higher expressions in the Pb group compared with control group (P < 0.05). However, the co-treatment of Se and Pb significantly alleviated those changes compared with the Pb group (P < 0.05). In conclusion, we speculated that Pb could increase the oxidative stress and promote the apoptosis via regulating mitochondrial dynamics and apoptosis-related genes, and Se exhibited antagonistic roles against the Pb-induced apoptosis in the kidney of chickens.

Protective Effects of PGC-1α Against Lead-Induced Oxidative Stress and Energy Metabolism Dysfunction in Testis Sertoli Cells

The reproductive system is sensitive to lead (Pb) toxicity, which has long been an area of research interest, but the underlying mechanisms remain to be illustrated. Peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α) is pivotal in mitochondrial function. In this study, mouse testis Sertoli cells (TM4 cells), PGC-1α lower-expression (PGC-1α(-)) TM4 cells and PGC-1α overexpression (PGC-1α(+)) TM4 cells were used to explore the protective roles of PGC-1α against lead toxicity on the mouse reproductive system. Lead acetate (PbAc) exposure decreased the expression level of PGC-1α, increased the intracellular level of reactive oxygen species (ROS), and reduced the level of ATP in the three TM4 cell lines. The effects of PbAc on intracellular ATP level and on ROS content were significantly weakened in PGC-1α(+)TM4 cells versus TM4 cells and were significantly amplified in PGC-1α(-)TM4 cells versus TM4 cells. These results suggest that PGC-1α is a protective factor against PbAc-induced oxidative stress and energy metabolism dysfunction in the mouse reproductive system, thereby holding the potential of being developed as a preventive or therapeutic strategy against disorders induced by lead exposure.