Zinc attenuates ethanol-induced Sertoli cell toxicity and apoptosis through caspase-3 mediated pathways

Ethanol enhances apoptosis in testicular germ cells. Zinc reduces ethanol-induced apoptosis of somatic cells through inhibition of caspase-mediated pathways. Little is known about the effects of ethanol on Sertoli cells and the effects of Zinc on ethanol-induced testicular injury. The hypothesis tested was that ethanol enhances apoptosis of Sertoli cells through up-regulation of caspase-3 and Zinc inhibits ethanol-induced effects. Cultured Sertoli cells (TM4) were exposed to ethanol (160 mM), Zinc (8 μM) and Zinc prior to ethanol for duration of 24 or 48 h and their effects on TM4 cell viability was then investigated by MTT assay. Caspase-3 mRNA expression was also investigated using real-time RT-PCR. Cell viability decreased and caspase-3 mRNA expresstion increased in cells exposed to ethanol, while exposure to Zinc showed opposite effects. Pretreatment with Zinc recovered ethanol-induced anti-proliferative effects and over-expression of caspase-3. Zinc reduced ethanol-induced Sertoli cell toxicity and apoptosis via caspase-3 mediated pathways.     

Benzene activates caspase-4 and -12 at the transcription level,without an association with apoptosis,in mouse bone marrow cells lacking the p53 gene

Benzene is a well-known environmental pollutant that can induce hematotoxicity, aplastic anemia, acute myelogenous leukemia, and lymphoma. However, although benzene metabolites are known to induce oxidative stress and disrupt the cell cycle, the mechanism underlying lympho/leukemogenicity is not fully understood. Caspase-4 (alias caspase-11) and -12 are inflammatory caspases implicated in inflammation and endoplasmic reticulum stress-induced apoptosis. The objectives of this study were to investigate the altered expression of caspase-4 and -12 in mouse bone marrow after benzene exposure and to determine whether their alterations are associated with benzene-induced bone marrow toxicity, especially cellular apoptosis. In addition, we evaluated whether the p53 gene is involved in regulating the mechanism, using both wild-type (WT) mice and mice lacking the p53 gene. For this study, 8-week-old C57BL/6 mice [WT and p53 knockout (KO)] were administered a benzene solution (150 mg/kg diluted in corn oil) via oral gavage once daily, 5 days/week, for 1 or 2 weeks. Blood and bone marrow cells were collected and cell counts were measured using a Coulter counter. Total mRNA and protein extracts were prepared from the harvested bone marrow cells. Then qRT-PCR and Western blotting were performed to detect changes in the caspases at the mRNA and protein level, respectively. A DNA fragmentation assay and Annexin-V staining were carried out on the bone marrow cells to detect apoptosis. Results indicated that when compared to the control, leukocyte number and bone marrow cellularity decreased significantly in WT mice. The expression of caspase-4 and -12 mRNA increased significantly after 12 days of benzene treatment in the bone marrow cells of benzene-exposed p53KO mice. However, apoptosis detection assays indicated no evidence of apoptosis in p53KO or WT mice. In addition, no changes of other apoptosis-related caspases, such as caspase-3 and -9, were found in WT or p53KO mice at the level of mRNA and proteins. These results indicated that upregulation of caspase-4 and -12 in mice lacking the p53 gene is not associated with cellular apoptosis. In conclusion, caspase-4 and -12 can be activated by benzene treatment without inducing cell apoptosis in mouse bone marrow, which are partly under the regulation of the p53 gene. J.-Y. Yi and Y. Hirabayashi contributed equally for this study.     

Evaluation of caspase-dependent apoptosis during fluoride-induced liver lesion in pigs

Sixteen barrows (Duroc×Landrace×Yorkshire) were randomly divided into two groups, each consisting eight pigs. The groups received the same basal diet supplemented with 0 and 400 mg/kg fluoride, respectively. Histological examinations, including in situ terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL), Haematoxylin and Eosin staining (HE) and transmission electron microscopy observation, found apoptotic hepatocytes 50 days after additional 400 mg/kg fluoride treatment. The obvious DNA ladder and the significantly increased both hepatic caspase-9 and caspase-3 activity indicated that fluoride induced caspase-dependent apoptosis in vivo. In addition, serum glutamate pyruvate transaminase (GPT) activity and hepatic lipid peroxides (LPO) concentration was significantly increased. The activity of serum glutamate oxaloacetate transaminase (GOT) showed an increased trend. The results suggest that fluoride induces apoptosis by elevating the oxidative stress-induced lipid peroxidation, causing mitochondrial dysfunction and further activating caspase-9 and caspase-3. The name of the laboratory where the work was carried out: Feed Science Institute in Zhejiang university     

Fluoride-induced apoptosis and gene expression profiling in mice sperm in vivo

Exposure to fluoride can induce low sperm quality; however, little is known about the molecular mechanisms by which fluoride exerts its toxic effects. This study was conducted to evaluate ultrastructure, oxidative stress, and apoptosis in sperm of mice treated with 150 mg/l NaF for 49 days. Furthermore, microarray analysis was also utilized to characterize the effects of fluoride in gene expression profiling on mice sperm. An increased ROS and a decreased TAC accompanied with distinct morphological changes and significant apoptosis were observed in mice sperm from the fluoride group. Fluoride exposure also significantly elevated the protein expressions of cytochrome c and active caspase-3. In global gene expression profiling, 34 up-regulated and 63 down-regulated genes, which are involved in several sperm biological processes including signal transduction, oxidative stress, apoptosis, electron transport, glycolysis, chemotaxis, spermatogenesis, and sperm capacitation, were significantly differentially expressed. Based on these findings, it was proposed that oxidative stress induced by excessive ROS may trigger sperm apoptosis through mitochondrial impairment, resulting in decreased fertility in mice exposed to fluoride. Microarray analysis also provided several important biological clues for further investigating fluoride-induced damage in sperm morphology and functions.     

Lactational coumestrol exposure increases ovarian apoptosis in adult rats

This study is the first to examine the increased apoptosis in the adult rat ovary after lactational exposure to coumestrol (COU), a potent phytoestrogen. Lactating dams were gavaged at doses of 0.01, 0.1, 1, and 10 mg/kg COU during the lactation period and the reproductive effects of female pups were investigated in young adults. Rats were sacrificed at postnatal days (PND) 81–84. Ovarian weights were reduced significantly at 0.1 and 1.0 mg/kg COU. The reduction in the ovarian weight occurred in parallel with an increase in the apoptosis at PND 135–140. A marked dose-dependent increase in the expressions of active caspase-3 and -7 was observed in ovarian granulosa cells. Immunostaining for active caspase-3 and the TUNEL staining of apoptotic cells were also increased in ovaries exposed to COU in a dose-dependent manner. These results suggest new sights into the effect of lactational exposure to COU on the female reproductive health. This article has been approved for publication by KFDA, but the views presented in this article do not necessarily reflect those of the KFDA.     

巴豆生物碱上调TRAIL配体、caspase-8的表达诱导HeLa细胞凋亡的体外研究

目的研究巴豆生物碱对人宫颈HeLa细胞诱导凋亡作用,并探讨其作用机制。方法 MTT法观察巴豆生物碱对HeLa细胞的抑制率;流式细胞仪检测HeLa细胞TRAIL及其受体DR5的表达及其巴豆生物碱对HeLa细胞TRAIL配体表达的影响;Caspase-8活性检测;RT-PCR检测TRAIL配体及Caspase-8、Caspase-3 mRNA的表达。结果巴豆生物碱对HeLa细胞生长有抑制作用,且呈剂量依赖关系。流式细胞仪检测HeLa细胞TRAIL及其受体DR5的表达阳性,巴豆生物碱处理HeLa细胞后发现TRAIL配体的表达明显上调,Caspase-8活性明显增加,TRAIL配体、Caspase-3及Caspase-8 mRNA高表达。结论巴豆生物碱对人宫颈癌HeLa细胞有增殖抑制和诱导细胞凋亡的作用,其诱导机制可能与上调TRAIL配体和Caspase-8mRNA的表达有关。     

Induction of HepG2 cell apoptosis by Irgarol 1051 through mitochondrial dysfunction and oxidative stresses

In this study, HepG2 cells were exposed to 0.04–40 mg/L Irgarol 1051. Results show that Irgarol 1051 can damage cell morphology and cause a significant decrease in cell viability. Positive staining by Annexin V, caspase-3 activity enhancement, and the damage in cell ultrastructure indicated an apoptotic mode of cell death for 4.0 mg/L Irgarol 1051 treatment. At the same time, caspase-9 was also significantly induced by 0.4 and 4.0 mg/L Irgarol 1051 at 72 h, which suggests that the intrinsic mitochondria pathway was involved in the apoptosis. The mitochondrial membrane potential decreased significantly after the HepG2 cells were exposed to Irgarol 1051 for 6 and 72 h. Especially, the translocation of cytochrome c from mitochondria to cytosol was recorded, supporting the idea that the mitochondrial pathway was involved in the apoptosis signal pathways induced by Irgarol 1051. The significantly increased levels of intracellular reactive oxygen species (ROS) and an immediate ROS burst were also recorded. The results here may imply that Irgarol 1051 induces HepG2 cell apoptosis through mitochondrial dysfunction and oxidative stresses. Although it is possible that this chemical has no detrimental effects on human health at the environmentally relevant concentration, it may cause problems to top coastal predators due to bio-accumulation through the food chain.     

Perfluorooctane sulfonate-induced testicular toxicity and differential testicular expression of estrogen receptor in male mice

Perfluorooctane sulfonate (PFOS, CAS#1763-23-1) causes male reproductive toxicities, but the underlying mechanisms are still unclear. In this study, 0, 0.5 and 10 mg/kg/day PFOS were given by oral gavage to adult mice for 5 weeks. In the 10 mg/kg group, serum testosterone levels decreased significantly. Sperm counts declined which might be associated with the decreased proliferation and increased apoptosis of germ cells. In relation to increased apoptosis, bax, cleaved caspase-9 and cleaved caspase-3 levels elevated significantly, indicating that PFOS induced germ cell apoptosis by activating the mitochondrial pathway. In addition, the increase in levels of testicular estrogen receptor (ER) β was observed in both 0.5 and 10 mg/kg group, whereas a decrease in ERα expression was only observed in 10 mg/kg group. These results suggested that the alterations in testicular ERs expression, together with decreased proliferation and increased apoptosis of germ cells, might be involved in PFOS-induced testicular toxicity.     

Relationship between fluoride exposure and osteoclast markers during RANKL-induced osteoclast differentiation

Skeletal fluorosis is a metabolic bone disease caused by excessive accumulation of fluoride. Although the cause of this disease is known, the mechanism by which fluoride accumulates on the bone has not been clearly defined, thus there are no markers that can be used for screening skeletal fluorosis in epidemiology. In this study, osteoclasts were formed from bone marrow cells of C57BL/6 mice-treated with macrophage colony stimulating factor and receptor activator of nuclear factor kappa-B ligand. The mRNA expression of tartrate-resistant acid phosphatase 5b (TRAP5b), osteoclast-associated receptor (OSCAR), calcitonin receptor (CTR), matrix metalloproteinase 9 (MMP9) and cathepsin K (CK) were detected using real-time PCR (RT-PCR). Results showed that fluoride between 0.5 and 8 mg/l had no effect on osteoclast formation. However fluoride at 0.5 mg/l level significantly decreased the activity of osteoclast bone resorption. Fluoride concentration was negatively correlated with the activity of osteoclast bone resorption. On day 5 of osteoclast differentiation maturity, MMP9 and CK mRNA expression were not only negatively correlated with fluoride concentration, but directly correlated with the activity of osteoclast bone resorption. TRAP5b, CTR and OSCAR mRNA expression were positively correlated with the number of osteoclast and they had no correlation with the activity of osteoclast bone resorption. Thus, it can be seen that MMP9 and CK may reflect the change of activity of bone resorption as well the degree of fluoride exposure. TRAP5b, CTR and OSCAR can represent the change of number of osteoclast formed.     

Dietary nickel chloride induces oxidative stress,apoptosis and alters Bax/Bcl-2 and caspase-3 mRNA expression in the cecal tonsil of broilers

The purpose of this study was to investigate the effects of dietary NiCl₂ on antioxidant function, apoptosis, and the protein expression, mRNA expression and contents of the bcl-2, bax and caspase-3 in the cecal tonsil of broilers. 280 one-day-old avian broilers were divided into four groups and fed on a corn–soybean basal diet as control diet or the same basal diet supplemented with 300, 600 and 900 mg/kg of NiCl₂ for 42 days. The activities of SOD, CAT and GSH-Px, and the ability to inhibit hydroxy radical, and GSH content were significantly decreased in all experimental groups. MDA content was significantly increased. The protein expression, mRNA expression and contents of bcl-2 were decreased, and bax and caspase-3 were increased in all experimental groups. The percentages of apoptotic lymphocytes were significantly increased. In conclusion, dietary NiCl₂ in excess of 300 mg/kg caused oxidative stress, and then induced decreased the protein expression, mRNA expression and the contents of bcl-2, and increased protein expression, mRNA expression and the contents of bax and caspase-3 proteins in the cecal tonsil. The local intestinal mucosal immunity could finally be impaired due to the oxidative stress and apoptosis in the cecal tonsil caused by NiCl₂.     

Trichothecin induces apoptosis of HepG2 cells via caspase-9 mediated activation of the mitochondrial death pathway

Trichothecin, one of fungal toxins which were encountered in food and in the environment, seriously threatens human and animal health. It has been shown that trichothecin changed the morphology of cellular mitochondria. However, the molecular mechanism remains unknown. Here we found that cell viability was attenuated by trichothecin. Features of apoptosis such as homosomal condensation and inter nucleosomal fragmentation were observed. In consistence with the elevated apoptosis rate, expression of anti-apoptotic protein Bcl-2 was diminished and expression of proapoptotic protein Bax was enhanced at mRNA levels. Furthermore, expression of caspase-9 and activity of caspase-3 were increased after the treatment of trichothecin. Accordingly, the mitochondrial membrane potential (?Ψm) was decreased in a dose-dependent manner. And Ca²⁺ overload was induced by trichothecin, followed by the generation of reactive oxygen species (ROS). Collectedly, our results suggested that apoptosis induced by trichothecin is mediated by caspase-9 activation and the decrement of mitochondrial function resulted from the overloaded calcium and ROS production.     

Sodium fluoride induces apoptosis in mouse embryonic stem cells through ROS-dependent and caspase- and JNK-mediated pathways

Sodium fluoride (NaF) is used as a source of fluoride ions in diverse applications. Fluoride salt is an effective prophylactic for dental caries and is an essential element required for bone health. However, fluoride is known to cause cytotoxicity in a concentration-dependent manner. Further, no information is available on the effects of NaF on mouse embryonic stem cells (mESCs). We investigated the mode of cell death induced by NaF and the mechanisms involved. NaF treatment greater than 1 mM reduced viability and DNA synthesis in mESCs and induced cell cycle arrest in the G₂/M phase. The addition of NaF induced cell death mainly by apoptosis rather than necrosis. Catalase (CAT) treatment significantly inhibited the NaF-mediated cell death and also suppressed the NaF-mediated increase in phospho-c-Jun N-terminal kinase (p-JNK) levels. Pre-treatment with SP600125 or z-VAD-fmk significantly attenuated the NaF-mediated reduction in cell viability. In contrast, intracellular free calcium chelator, but not of sodium or calcium ion channel blockers, facilitated NaF-induced toxicity in the cells. A JNK specific inhibitor (SP600125) prevented the NaF-induced increase in growth arrest and the DNA damage-inducible protein 45α. Further, NaF-mediated loss of mitochondrial membrane potential was apparently inhibited by pifithrin-α or CAT inhibitor. These findings suggest that NaF affects viability of mESCs in a concentration-dependent manner, where more than 1 mM NaF causes apoptosis through hydroxyl radical-dependent and caspase- and JNK-mediated pathways.     

Aberrant methylation‐induced dysfunction of p16 is associated with osteoblast activation caused by fluoride

Chronic exposure to fluoride continues to be a public health problem worldwide, affecting thousands of people. Fluoride can cause abnormal proliferation and activation of osteoblast and osteoclast, leading to skeletal fluorosis that can cause pain and harm to joints and bones and even lead to permanent disability. Nevertheless, there is no recognized mechanism to explain the bone lesions of fluorosis. In this work, we performed a population study and in vitro experiments to investigate the pathogenic mechanism of skeletal fluorosis in relation to methylation of the promoter of p16. The protein coded by the p16 gene inhibits cdk (cyclin‐dependent kinase) 4/cdk6‐mediated phosphorylation4 of retinoblastoma gene product and induces cell cycle arrest. The results showed that hypermethylation of p16 and reduced gene expression was evident in peripheral blood mononuclear cells of patients with fluorosis and correlated with the level of fluoride exposure. Studies with cell cultures of osteoblasts revealed in response to sodium fluoride (NaF) treatment, there was an induction of p16 hypermethylation and decreased expression, leading to increased cell proliferation, a longer S‐phase of the cell cycle, and development of skeletal fluorosis. Further, the methylation inhibitor, 5‐aza‐2‐deoxycytidine, reversed the p16 hypermethylation and expression in response to NaF. These results reveal a regulatory role of p16 gene methylation on osteoblasts activation during the development of skeletal fluorosis.     

Simvastatin activates Akt/glycogen synthase kinase-3β signal and inhibits caspase-3 activation after experimental subarachnoid hemorrhage

This study was designed to explore the role of simvastatin and its effects on the Akt/GSK3β survival signal and apoptosis pathway after experimental subarachnoid hemorrhage (SAH). SAH was induced by blood injection into the cisterna magna in New Zealand white rabbits. Increased expression of phospho-Akt and phospho-GSK3β was observed in brain tissue after SAH. Apoptosis and related proteins, including P53, apoptosis-inducing factor (AIF), cytochrome C, and cleaved caspase-3, were also activated. Simvastatin, at both low dose (10 mg/kg) and high dose (40 mg/kg), further increased expression of phospho-Akt and phospho-GSK3β, decreased activation of caspase-3, and inhibited apoptosis. Preserved blood-brain barrier and attenuated brain edema were observed following simvastatin treatment. In addition, the neuroprotective effects of simvastatin were blocked by wortmannin (2.5 µg/kg/min), an irreversible PIK3 inhibitor. P53, AIF, and cytochrome C were not affected by simvastatin treatment. Findings from the present study suggest that simvastatin ameliorates acute brain injury after SAH. The potential mechanisms of action include activation of the Akt/GSK3β survival signal and inhibition of caspase-dependent apoptosis pathway.     

Effect of fluoride exposure on mRNA expression of cav1.2 and calcium signal pathway apoptosis regulators in PC12 cells

This study investigated the effects of fluoride exposure on the mRNA expression of Cav1.2 calcium signaling pathway and apoptosis regulatory molecules in PC12 cells. The viability of PC12 cell receiving high fluoride (5.0 mM) and low fluoride (0.5 mM) alone or fluoride combined with L-type calcium channel (LTCC) agonist/inhibitor (5 umol/L FPL6417/2 u mol/L nifedipine) was detected using cell counting kit-8 at different time points (2, 4, 6, 8, 12, 10, and 24 h). Changes in the cell configuration were observed after exposing the cells to fluoride for 24 h. The expression levels of molecules related to the LTCC were examined, particularly, Cav1.2, c-fos, CAMK II, Bax, and Bcl-2. Fluoride poisoning induced severe cell injuries, such as decreased PC12 cell activity, enhanced cell apoptosis, high c-fos, CAMKII, and Bax mRNA expression levels. Bcl-2 expression level was also reduced. Meanwhile, high fluoride, high fluoride with FPL64176, and low fluoride with FPL64176 enhanced the Cav1.2 expression level. In contrast, low fluoride, high fluoride with nifedipine, and low fluoride with nifedipine reduced the Cav1.2 expression level. Thus, Cav1.2 may be an important molecular target for the fluorosis treatment, and the LTCC inhibitor nifedipine may be an effective drug for fluorosis.     

巴豆生物碱诱导Hela细胞凋亡及其作用机制

目的研究巴豆生物碱(CA)在体外诱导宫颈癌Hela细胞凋亡及其作用机制。方法 MTT法检测CA对Hela细胞增殖的抑制率;AnnexinV-PI染色检测细胞凋亡;Caspase-8试剂盒检测Caspase-8在Hela细胞中的活性;RT-PCR检测Caspase-8 mRNA的表达。结果巴豆生物碱对Hela细胞生长有抑制作用,且呈剂量依赖关系。流式细胞术结果提示CA可诱导Hela细胞凋亡。CA处理Hela细胞后发现Caspase-8活性明显增加,Caspase-8的mRNA高表达。结论 CA对人宫颈癌Hela细胞有增殖抑制和诱导凋亡作用,其诱导Hela细胞凋亡的分子机制可能与上调Caspase-8基因表达有关。     

Non-apoptotic functions of caspase-8

Caspases are a family of aspartate-specific cysteine proteases that have been well characterized for their function in apoptosis signaling. Caspase-8 is implicated as an initiator caspase in death receptor-induced signaling to apoptosis and has been studied most extensively for its role in CD95-induced cell death. CD95 stimulation induces the binding of caspase-8 to a death-inducing signaling complex, leading to its autocatalytic cleavage and the formation of a caspase-8 homodimer, which is subsequently released into the cytosol where it further mediates the apoptotic signaling cascade. Over the past few years, however, several non-apoptotic functions for caspase-8 have been described, indicating that this protease plays a much more diverse role than previously assumed. Here we review the role of caspase-8 in embryonic development, monocyte differentiation, T and B cell proliferation, and the activation of NF-κB.     

Nonylphenol induces apoptosis via mitochondria- and Fas-l-mediated pathways in the liver of adult male rat

Nonylphenol (NP) is an environmental contaminant known to possess estrogenic properties. Humans are constantly exposed to NP by contaminated water and food products. In the present study we sought to investigate whether treatment with low doses of NP induces apoptosis in the liver of adult rats. Rats were administered with NP by oral gavage at the doses of 15,150 and 1500 μg/kg body weight per day for 45 days. Plasma aspartate aminotransferase (AST) and alanine aminotransferase (ALT) were assayed. Apoptosis-related proteins namely cytochrome c, caspase-3, caspase-8, caspase-9, Fas and Fas-l, and expression of bcl-2 mRNA and bax mRNA were examined in the liver. Levels of AST and ALT were increased in the treated rats. Western blot analysis revealed elevation in the levels of cytochrome c, caspase-3, caspase-8, caspase-9, Fas and Fas-l in the liver of NP-treated rats. Decreased expression of bcl-2 mRNA (anti-apoptotic) and increased expression of bax mRNA (apoptotic) were observed in the liver of treated rats. Increased localization of caspase-3 in the hepatocytes and DNA damage were observed in the liver of treated rat. It is concluded that NP induces apoptosis in liver involving both mitochondria-dependent and Fas–Fas-l pathways and thereby, leading to hepatic damage in rats.     

Leptin is upregulated in epididymitis and promotes apoptosis and IL-1β production in epididymal epithelial cells by activating the NLRP3 inflammasome

Epididymitis, one of the most common urological disease, is a significant cause of male infertility. Leptin is capable of modulating both reproduction and immune response. We analyzed the serum and seminal plasma levels of leptin in infertile patients with or without chronic epididymitis. Experimental epididymitis models were generated by administrating 200 μg Lipopolysaccharide (LPS) to Sprague-Dawley rats. The expression of leptin in epididymis were detected using qPCR, Western blots 6–72 h after injection, and using immunohistochemistry 72 h after injection. Besides, rat epididymal epithelial cells were isolated as an in vitro model and were treated with leptin (5–40 ng/ml, 6–48 h), LPS (1ug/ml, 6 h), and NLRP3 inflammasome inhibitor MCC950 (10 μM, 2 h). Cell Counting Kits-8 assay and Annexin V/PE assay were used to evaluate cell viability and apoptosis. Quantitive PCR and ELISA assay were used to detected inflammatory cytokines interleukin-1beta (IL-1β) production. Western Blots were used to detect molecular related to cell apoptosis, IL-1β maturation, and NLRP3 inflammasome. We found that patients with chronic epididymitis presented a significantly higher level of seminal plasma leptin and correlated declined sperm progressive motility. Leptin and leptin receptor expression in epididymis was significantly upregulated 24 h after LPS administration both in mRNA and protein level, and highly expressed in the epididymis epithelium 72 h after LPS administration. In epididymal epithelial cells, leptin reduced cell viability and promoted apoptosis in a concentration-dependent manner via cleavage of caspase-9, caspase-3, and PARP. Leptin enhanced the LPS-induced production of IL-1β, which was associated with increased IL-1β maturation and caspase-1 activation. Furthermore, NLRP3 inhibitor MCC950 attenuated the effects of leptin or co-treatment with LPS on NLRP3, ASC expression, IL-1β maturation, and caspase-1 activation, which indicated that leptin promotes IL-1β production via activating the NLRP3 inflammasome. These data suggested that leptin may act as a potential evaluation and treatment target for epididymitis and male subfertility.     

Goniothalamin-induced oxidative stress,DNA damage and apoptosis via caspase-2 independent and Bcl-2 independent pathways in Jurkat T-cells

Goniothalamin (GTN) isolated from Goniothalamus sp. has been demonstrated to induce apoptosis in a variety of cancer cell lines including Jurkat T leukemia cells. However, the mechanism of GTN-induced apoptosis upstream of mitochondria is still poorly defined. In this study, GTN caused a decrease in GSH with an elevation of reactive oxygen species as early as 30 min and DNA damage as assessed by Comet assay. Analysis using topoisomerase II processing of supercoiled pBR 322 DNA showed that GTN caused DNA damage via a topoisomerase II-independent pathway suggesting that cellular oxidative stress may contribute to genotoxicity. A 12-fold increase of caspase-2 activity was observed in GTN-treated Jurkat cells after 4 h treatment and this was confirmed using Western blotting. Although the caspase-2 inhibitor Z-VDVAD-FMK inhibited the proteolytic activity of caspase-2, apoptosis ensued confirming that caspase-2 activity was not crucial for GTN-induced apoptosis. However, GTN-induced apoptosis was completely abrogated by N-acetylcysteine further confirming the role of oxidative stress. Since cytochrome c release was observed as early as 1 h without any appreciable change in Bcl-2 protein expression, we further investigated whether overexpression of Bcl-2 confers resistance in GTN-induced cytotoxicity. Using a panel of Jurkat Bcl-2 transfectants, GTN cytotoxicity was not abrogated in these cells. In conclusion, GTN induces DNA damage and oxidative stress resulting in apoptosis which is independent of both caspase-2 and Bcl-2.