Nickel sulfate induced apoptosis via activating ROS‐dependent mitochondria and endoplasmic reticulum stress pathways in rat Leydig cells

Nickel can induce apoptosis of testicular Leydig cells in mice, whereas the mechanisms remain unclear. In this study, we investigated the role of nickel‐induced reactive oxygen species (ROS) generation in mitochondria and endoplasmic reticulum stress (ERS) mediated apoptosis pathways in rat Leydig cells. Fluorescent DCF and Annexin‐V FITC/PI staining were performed to measure the production of ROS and apoptosis in Leydig cells. RT‐qPCR and Western blot were conducted to analyze the key genes and proteins involved in mitochondria and ERS apoptotic pathways. The results showed that nickel sulfate induced ROS generation, consequently resulted in nucleolus deformation and apoptosis in testicular Leydig cells, which were then attenuated by ROS inhibitors of N‐acetylcysteine (NAC) and 2,2,6,6‐tetramethyl‐1‐piperidinyloxy (TEMPO). Nickel sulfate‐triggered Leydig cells apoptosis via mitochondria and ERS pathways was characterized by the upregulated mRNA and proteins expression of Bak, cytochrome c, caspase 9, caspase 3, GRP78, GADD153, and caspase 12, which were inhibited by NAC and TEMPO respectively. The findings indicated that nickel‐induced ROS generation was involved in apoptosis via mitochondria and ERS pathways in rat Leydig cells.     

2.45 GHz microwave radiation induced oxidative and nitrosative stress mediated testicular apoptosis: Involvement of a p53 dependent bax‐caspase‐3 mediated pathway

Deleterious effects of MW radiation on the male reproduction are well studied. Previous reports although suggest that 2.45 GHz MW irradiation induced oxidative and nitrosative stress adversely affects the male reproductive function but the detailed molecular mechanism occurring behind it has yet to be elucidated. The aim of present study was to investigate the underlying detailed pathway of the testicular apoptosis induced by free radical load and redox imbalance due to 2.45 GHz MW radiation exposure and the degree of severity along with the increased exposure duration. Twelve‐week old male mice were exposed to 2.45 GHz MW radiation [continuous‐wave (CW) with overall average Power density of 0.0248 mW/cm² and overall average whole body SAR value of 0.0146 W/kg] for 2 hr/day over a period of 15, 30, and 60 days. Testicular histology, serum testosterone, ROS, NO, MDA level, activity of antioxidant enzymes, expression of pro‐apoptotic proteins (p53 and Bax), anti‐apoptotic proteins (Bcl‐2 and Bcl‐x_L), cytochrome‐c, inactive/active caspase‐3, and uncleaved PARP‐1 were evaluated. Findings suggest that 2.45 GHz MW radiation exposure induced testicular redox imbalance not only leads to enhanced testicular apoptosis via p53 dependent Bax‐caspase‐3 mediated pathway, but also increases the degree of apoptotic severity in a duration dependent manner.     

辛伐他汀通过内质网应激途径诱导K562细胞凋亡

探讨内质网应激在辛伐他汀诱导K562细胞凋亡中的作用。采用荧光显微镜观察凋亡细胞的形态变化，AnnexinV-FITC/PI双染法检测细胞凋亡率，激光扫描共聚焦显微镜检测细胞内Ｃa²⁺浓度，RT-PCR检测葡萄糖调节蛋白78(glucose regulated protein 78，GRP78)、钙蛋白酶(calpain)基因mRNA表达水平，Western blotting检测GRP78、 calpain、 caspase-3， -6， -7， -9， -12蛋白水平。结果显示，10、 20、 30 μmol·L^-1辛伐他汀(simvastatin，Sim)作用K562细胞72 h后，细胞出现典型的凋亡形态，凋亡率分别为12.41%、 19.08%和23.41%；细胞内Ca²⁺浓度增加，荧光强度分别为43、54和64；GRP78、calpain基因mRNA表达上调；calpain、 caspase-3， -6， -7， -9， -12蛋白剪切活化、GRP78蛋白表达增强。以上结果表明，内质网作为细胞凋亡的重要途径参与了辛伐他汀诱导K562细胞的凋亡。辛伐他汀将可能被用于临床治疗白血病。     

Atrazine induces endoplasmic reticulum stress‐mediated apoptosis of T lymphocytes via the caspase‐8‐dependent pathway

Atrazine (ATR) is one of the most commonly applied broad‐spectrum herbicides. Although ATR is well known to be a biologically hazardous molecule with potential toxicity in the immune system, the molecular mechanisms responsible for ATR‐induced immunotoxicity remain unclear. In this study, we found that the immunotoxic properties of ATR were mediated through the induction of apoptotic changes in T lymphocytes. Mice exposed to ATR for 4 weeks exhibited a significant decrease in the number of spleen CD3⁺ T lymphocytes, while CD19⁺ B lymphocytes and nonlymphoid cells were unaffected. ATR exposure also led to inhibition of cell growth and induction of apoptosis in human Jurkat T‐cells. Importantly, ATR triggered the activation of caspase‐3 and the cleavage of caspase‐8 and PARP, whereas it did not affect the release of cytochrome c from the mitochondria in Jurkat T‐cells. In addition, ATR activated the unfolded protein response signaling pathway, as indicated by eIF2α phosphorylation and CHOP induction. Our results demonstrate that ATR elicited an immunotoxic effect by inducing ER stress‐induced apoptosis in T‐cells, therefore providing evidence for the molecular mechanism by which ATR induces dysregulation of the immune system. © 2015 Wiley Periodicals, Inc. Environ Toxicol 31: 998–1008, 2016.     

Dithiothreitol enhanced arsenic‐trioxide‐induced cell apoptosis in cultured oral cancer cells via mitochondrial dysfunction and endoplasmic reticulum stress

Arsenic is naturally occurring toxic metalloid and drinking As₂O₃ containing water are recognized to be related to increased risk of neurotoxicity, liver injury, blackfoot disease, hypertension, and cancer. On the contrary, As₂O₃ has been an ancient drug used in traditional Chinese medicine with substantial anticancer activities, especially in the treatment of acute promyelocytic leukemia as well as chronic wound healing. However, the cytotoxicity and detail mechanisms of As₂O₃ action in solid cancer cells, such as oral cancer cells, are largely unknown. In this study, we have primarily cultured four pairs of tumor and nontumor cells from the oral cancer patients and treated the cells with As₂O₃ alone or combined with dithiothreitol ( DTT). The results showed that 0.5 μM As₂O₃ plus 20 μM DTT caused a significant cell death of oral cancer cells but not the nontumor cells. Also As₂O₃ plus DTT upregulated Bax and Bak, downregulated Bcl‐2 and p53, caused a loss of mitochondria membrane potential in oral cancer cells. On the other way, As₂O₃ also triggered endoplasmic reticulum stress and increased the levels of glucose‐regulated protein 78, calpain 1 and 2. Our results suggest that DTT could synergistically enhance the effects of As₂O₃ on killing oral cancer cells while nontoxic to the nontumor cells. The combination is promising for clinical practice in oral cancer therapy and worth further investigations. © 2015 Wiley Periodicals, Inc. Environ Toxicol 32: 17–27, 2017.     

Cantharidin-induced LO2 cell autophagy and apoptosis via endoplasmic reticulum stress pathway in vitro

Cantharidin (CTD), an important active compound derived from the traditional Chinese medicine Mylabris (also called Banmao), has been used in the treatment of diseases such as tumors and dermatosis. However, Mylabris has been shown to induce hepatotoxicity in clinical practice and animal experiments, limiting its use. Further, a detailed mechanism underlying CTD-induced hepatotoxicity has not been determined. In the present study, we aimed to explore the effect of endoplasmic reticulum stress (ERS), autophagy, and apoptosis on CTD-induced hepatotoxicity. We found that CTD could inhibit the proliferation of LO2 cells; increase alanine aminotransferase, aspartate aminotransferase, lactate dehydrogenase, and malondialdehyde levels; and reduce glutathione peroxidase and superoxide dismutase activities. Western blotting showed that low concentrations of CTD induced the expressions of ERS-related proteins [GRP78, ATF4, PERK, p-PERK, XBP1–1 s, and CHOP], but high concentrations of CTD inhibited their expressions. Furthermore, high concentrations of CTD activated autophagy (LC3, Beclin-1, Atg3, Atg4A, Atg4B, and Atg7), induced the expressions of apoptotic proteins (Bax/Bcl-2 and caspase-3), and increased LO2 toxicity. Taken together, these results indicated that CTD can induce LO2 cytotoxicity by inhibiting ERS and inducing autophagy and apoptosis, which provides a scientific basis for CTD-induced hepatotoxicity.     

内质网应激与神经元退行性变

内质网(endoplasmic reticulum,ER)是蛋白质修饰、折叠和钙贮存的场所。ER内未折叠或错折叠蛋白积聚和钙平衡失调均可导致ER应激。早期的ER应激或未折叠蛋白反应,是一种自身代偿过程,对细胞起到保护作用,而长期、严重的ER应激则会诱导细胞凋亡及死亡。研究发现,ER应激在许多神经退行性疾病的病理机制中起重要作用。然而,确切的机制目前仍不清楚。该文就ER应激在神经元退行性变中的作用作一综述。     

Silver nanoparticle‐induced oxidative stress,genotoxicity and apoptosis in cultured cells and animal tissues

Silver nanoparticles (AgNPs) have emerged as an important class of nanomaterials for a wide range of industrial and medical applications. However, the unique properties of AgNPs could potentially lead to unexpected hazards to both human health and the well being of the environment. Possible mechanisms of AgNP‐induced toxicity include the stimulation of oxidative stress, genotoxicity and apoptosis. In this study, a number of previous studies are therefore summarized that demonstrate oxidative stress‐, genotoxicity‐ and apoptosis‐related changes brought about by AgNPs in cultured cells and animal tissues. The physicochemical properties of AgNPs that are involved in encouraging such changes are also discussed. Copyright © 2012 John Wiley & Sons, Ltd.     

TXNIP介导的氧化应激在疾病中的作用机制

硫氧还蛋白相互作用蛋白(TXNIP)通过与硫氧还蛋白(Trx)的结合而抑制Trx的抗氧化作用,促进了活性氧簇(ROS)的产生与积聚,诱发内质网应激与线粒体应激,最终可诱导炎症或细胞凋亡。TXNIP所介导的氧化应激在糖尿病及其并发症(糖尿病肾病、糖尿病视网膜病变等)、动脉粥样硬化、缺血/再灌注损伤、癌症(肝细胞癌、膀胱癌、乳腺癌、白血病)等疾病的发生、发展过程中起着重要的调控作用。该文就TXNIP介导的氧化应激在相关疾病中的作用机制及研究进展进行综述。     

五味子乙素通过ROS介导内质网应激诱导人乳腺癌MDA-MB-231细胞凋亡的研究

目的 研究五味子乙素对人乳腺癌MDA-MB-231细胞凋亡的影响及其作用机制。方法 用细胞计数试剂(CCK-8)检测不同浓度五味子乙素对MDA-MB-231细胞存活率的影响;五味子乙素（10、20、40 μmol/L）作用 MDA-MB-231 细胞 24 h,分别用Annexin V-FITC/PI检测细胞凋亡情况;用DCFA-DA荧光探针检测细胞内活性氧（ROS）水平;用Western blot法检测细胞凋亡及内质网应激相关蛋白（Bcl-2、Bax、CHOP、GPR78、PERK、p-PERK、p-eIF2α、eIF2）的表达。结果 与空白组比较,随着五味子乙素浓度增大,细胞存活率明显降低,其IC₅₀为19.16 μmol/L;与对照组比较,五味子乙素（10、20、40 μmol/L）均能抑制细胞克隆形成(P<0.05),且呈剂量依赖;五味子乙素（10、20、40 μmol/L）均可诱导细胞凋亡（P<0.05）,使抗凋亡蛋白BCL-2的表达显著降低,促凋亡蛋白Bax的表达显著升高(P<0.05);五味子乙素（10、20、40 μmol/L）显著升高细胞内ROS水平(P<0.05),且呈剂量依赖;五味子乙素（10、20、40 μmol/L）能够激发内质网应激,使内质网应激相关蛋白CHOP、GPR78、p-eIF2α表达增多(P<0.05),且呈剂量依赖。结论 五味子乙素可能通过ROS介导内质网应激诱导MDA-MB-231细胞凋亡。     

Arsenite‐induced endoplasmic reticulum‐dependent apoptosis through disturbance of calcium homeostasis in HBE cell line

Calcium (Ca²⁺) is a ubiquitous cell signal responsible for multiple fundamental cellular functions, including apoptosis. Whether the homeostasis of Ca²⁺ is involved in arsenite‐induced apoptosis remains unclear. In this study, we observed that arsenite significantly elevated the intracellular Ca²⁺ concentration in a dose‐ and time‐dependent manner. By using the Ca²⁺‐ATPase inhibitor, thapsigargin, and the inositol 1,4,5‐ trisphosphate receptors (IP3Rs) inhibitor, heparin, we further confirmed that the disturbance of endoplasmic reticulum (ER) Ca²⁺ homeostasis caused Ca²⁺ overload in the cells. Moreover, loss of ER Ca²⁺ homeostasis also led to ER stress, mitochondrial dysfunction, and NF‐κB activation. Importantly, pretreatment of cells with heparin remarkably attenuated the elevated cell apoptosis induced by arsenite, but inhibition of ER Ca²⁺ uptake with thapsigargin exacerbated arsenite‐induced cell damage significantly. Together, we demonstrated for the first time that arsenite disturbed the Ca²⁺ homeostasis in ER, which subsequently led to ER stress, mitochondrial dysfunction, and NF‐κB nuclear translocation, and thus consequently triggering cell apoptosis. Our findings indicate regulation of disrupted Ca²⁺ homeostasis in ER may be a potential strategy for prevention of arsenite toxicity. © 2015 Wiley Periodicals, Inc. Environ Toxicol 32: 197–216, 2017.     

白芍总苷对糖尿病大鼠心肌氧化应激和细胞凋亡的影响及机制研究

目的 探讨白芍总苷(total glucosides ofpaeony,TGP)对糖尿病大鼠心肌氧化应激和细胞凋亡的影响及其机制.方法 取120只SD大鼠按随机数字表法分为对照组、模型组、二甲双胍(Met,200 mg/kg)组和TGP低、中、高剂量(50、100、200 mg/kg)组,每组20只;采用一次性ip链脲...     

Endoplasmic reticulum may not be involved in the lead‐induced apoptosis in PC 12 cells in vitro

Recent researches indicated that mitochondrial pathway might play an important role in lead‐induced apoptosis. Our previous study also found that lead could induce apoptosis in PC 12 cells, and mitochondrial pathway events were involved in this process. As lead can disturb Ca²⁺ homeostasis, the present study was undertaken to determine whether lead can activate key cellular events in the endoplasmic reticulum (ER) pathway, including the expressions of C/EBP homology protein (CHOP) and glucose‐regulated protein 78 (GRP78), and the activation of caspase‐12 and calpain. The results showed that lead could increase the expression of GRP78, while the expressions of CHOP and procaspase‐12 remained unchanged. Moreover, the caspase‐12 and calpain were not activated, and the ultrastructure of endoplasmic reticulum was not altered. Therefore, it suggests that lead may induce apoptosis in PC 12 cells through mitochondrial pathway, but not through the endoplasmic reticulum pathway. © 2009 Wiley Periodicals, Inc. Environ Toxicol, 2010.     

氧化应激致PC12细胞凋亡的信号传导途径的研究进展

PC12细胞被广泛用于神经细胞功能、分化、凋亡和神经递质分泌,以及潜在的分子机制的研究。氧化应激可导致PC12细胞凋亡,其作用方式为激活对氧化还原反应敏感的细胞信号传导,主要与丝裂原活化蛋白激酶、线粒体凋亡及NF-κB信号传导途径有关。本文综述了氧化应激致PC12细胞凋亡的信号传导途径,旨在为神经系统氧化应激相关疾病的抗氧化剂药物治疗和凋亡信号途径药物干预治疗提供理论依据。     

The role of GSH in microcystin‐induced apoptosis in rat liver: Involvement of oxidative stress and NF‐κB

Microcystins (MCs) are potent and specific hepatotoxins produced by cyanobacteria in eutrophic waters, representing a health hazard to animals and humans. The objectives of this study are to determine the relationship between oxidative stress and NF‐κB activity in MC‐induced apoptosis in rat liver and the role of glutathione (GSH). Sprague‐Dawley rats were intraperitoneally (i.p.) injected with microcystin‐LR (MC‐LR) at 0.25 and 0.5 LD₅₀ with or without pretreatment of buthionine‐(S,R)‐sulfoximine (BSO), a specific GSH synthesis inhibitor. MC‐LR induced time‐dependent alterations of GSH levels in rat liver. Increased malondialdehyde (MDA) and significant changes of antioxidant enzymes including GSH peroxidase (GPX) and GSH reductase (GR) were also observed, particularly at 24 h post‐exposure. The results indicated that acute exposure to MC‐LR induced oxidative stress, and GSH depletion (BSO pretreatment) enhanced the level of oxidative stress. Furthermore, the modulation of pro‐apoptotic gene p53 and Bax and anti‐apoptotic gene Bcl‐2 was observed in 0.5 LD₅₀ group at 24 h, and the alteration was more pronounced by BSO injection before MC‐LR treatment, suggesting that GSH played a protective role against MC‐induced toxicity. Additionally, electrophoretic mobility shift assay (EMSA) showed that NF‐κB was induced at 0.25 LD₅₀ but inhibited at 0.5 LD₅₀. The above results indicated that the possible crosstalk of oxidative stress and NF‐κB activity was associated with MC‐LR‐induced hepatocytes apoptosis in vivo. Our data will provide a new perspective for understanding the mechanisms of MC‐induced liver injury. © 2014 Wiley Periodicals, Inc. Environ Toxicol 31: 552–560, 2016.