• Journal of Microbiology and Biotechnology
• /
• 제27권1호
• /
• pp.197-205
• /
• 2017

Exposure of Jurkat T cell clone (J/Neo cells) to acacetin (5,7-dihydroxy-4'-methoxyflavone), which is present in barnyard millet (Echinochloa esculenta (A. Braun)) grains, caused cytotoxicity, enhancement of apoptotic $sub-G_1$ rate, Bak activation, loss of mitochondrial membrane potential (${\Delta}{\Psi}m$), activation of caspase-9 and caspase-3, degradation of poly(ADP-ribose) polymerase, and FITC-Annexin V-stainable phosphatidylserine exposure on the external surface of the cytoplasmic membrane without accompanying necrosis. These apoptotic responses were abrogated in Jurkat T cell clone (J/Bcl-xL) overexpressing Bcl-xL. Under the same conditions, cellular autophagic responses, including suppression of the Akt-mTOR pathway and p62/SQSTM1 down-regulation, were commonly detected in J/Neo and J/Bcl-xL cells; however, formation of acridine orange-stainable acidic vascular organelles, LC3-I/II conversion, and Beclin-1 phosphorylation (Ser-15) were detected only in J/Neo cells. Correspondingly, concomitant treatment with the autophagy inhibitor (3-methyladenine or LY294002) appeared to enhance acacetin-induced apoptotic responses, such as Bak activation, ${\Delta}{\Psi}m$ loss, activation of caspase-9 and caspase-3, and apoptotic $sub-G_1$ accumulation. This indicated that acacetin could induce apoptosis and cytoprotective autophagy in Jurkat T cells simultaneously. Together, these results demonstrate that acacetin induces not only apoptotic cell death via activation of Bak, loss of ${\Delta}{\Psi}m$, and activation of the mitochondrial caspase cascade, but also cytoprotective autophagy resulting from suppression of the Akt-mTOR pathway. Furthermore, pharmacologic inhibition of the autophagy pathway augments the activation of Bak and resultant mitochondrial damage-mediated apoptosis in Jurkat T cells.

• Journal of Microbiology and Biotechnology
• /
• 제12권6호
• /
• pp.950-956
• /
• 2002

The antitumor activity of the insect pathogenic fungus Paecilomyces japonica has been attributed to apoptotic cell death. However, the mechanism underlying the induced apoptosis has not yet been elucidated. In this study, we for the first time show that mitochondria-dependent caspase-3 activation were associated with the apoptotic activity of P. japonica in human acute leukemia Jurkat T cells. When Jurkat T cells were treated with the ethyl acetate extract of P japonica at concentrations ranging from $2-6{\mu}g/ml$, apoptotic cell death. accompanied by several biochemical events such as caspase-9 activation, caspase-3 activation, degradation of poly (ADP-ribose) polymerase (PARP), and apoptotic DNA fragmentation, was induced in a dose-dependent manner. In addition, the release of cytochrome c from mitochondria was detected. Under these conditions, the expression of Fas and Fas-ligand (FasL) remained unchanged. Ethyl acetate extract-induced mitochondrial cytochrome c release, caspase-3 activation, PARP cleavage, and apoptotic DNA fragmentation were suppressed by the ectopic expression of Bcl-2, which is known to block mitochondrial cytochrorme c release. Accordingly, these results demonstrate that P. japonica-induced apoptotic cell death is mediated by a cytochrome c-dependent caspase-3 activation pathway that can be interrupted by Bcl-2.

• Toxicological Research
• /
• 제19권3호
• /
• pp.197-203
• /
• 2003

Apicidin, a histone-deacetylase inhibitor, has been successfully used to inhibit the growth of cancer cells. In this study, the apoptotic potential and mechanistic insights of apicidin were investigated in human myeloid leukemia U937 cells. Treatment of U937 cells with apicidin resulted in a decrease of cell viability with apoptotic characteristics, including chromatin condensation and ladder-pattern fragmentation of genomic DNA. Apicidin converted the procaspase-3 protease to catalytically active effector protease, resulting in subsequent cleavage of poly (ADP-ribose) polymerase (PARP) and inhibitor of caspase-activated deoxyribonuclease (ICAD). In addition, apicidin induced the activation of caspase-9 protease and the cytosolic release of mitochondrial cytochrome c with mitochon-drial membrane potential transition. Moreover, apicidin transiently increased the expression of Fas and Fas ligand proteins. Taken together, the results suggest that apicidin induces apoptosis of U937 cells through activation of intrinsic caspase cascades and Fas/FasL system with mitochondrial dysfunction.

• Toxicological Research
• /
• 제18권3호
• /
• pp.259-265
• /
• 2002

Resveratrol, a phytoalexin found in grapes, berries, and peanuts, is one of the most promising agents for cancer prevention. Recent studies show that the antitumor activity of resveratrol occurs through p53-mediated apoptosis. This study demonstrated the mechanism that resveratrol induced apoptosis in human osteosarcoma Saos-2 cells lacking p53. Treatment of osteosarcoma Saos-2 cells with resveratrol resulted in decrease of cell viability, which was revealed as apoptosis characterized by activation of caspase-3 protease as well as cleavage of poly(ADP-ribose) polymerase (PARP) with change of mitochondrial membrane potential transition. These results suggest that resveratrol may be potentially useful to treat osteosarcoma via activation of caspase protease and mitochondrial dysfunction.

• Toxicological Research
• /
• 제18권3호
• /
• pp.275-283
• /
• 2002

Fungal metabolite, gliotoxin is an epipolythiodioxopiperazin (ETP) class and has various roles including immunomodulatory and apoptotic effects. This study was designed to evaluate the mechanism by which gliotoxin exerts the apoptosis on human promyelocytic leukemic HL-60 cells. Herein, we demonstrated that the gliotoxin decreased the cell viability in a time-dependent manner Gliotoxin-induced cell death was confirmed us apoptosis characterized by chromatin condensation and ladder-pattern fragmentation of genomic DNA. Gliotoxin increased the catalytic activities of caspase-3 and caspase-9. Activation of caspase-3 was further confirmed by degradation of procaspase-3 and poly(ADP-ribose) polymerase (PARP) by gliotoxin in HL-60 cells. Furthermore, gliotoxin induced the changes of mitochondrial transmembrane potential (MTP). Antioxidants, including GSH and NAC, markedly inhibited apoptosis with conistent suppression of enzymatic activity of caspase-3, caspase-9, and MTP loss in gliotoxin-treated cells. Taken together, we suggest that gliotoxin function as an oxidant and ploys proapoptotic roles in HL-60 cells via activation of intrinsic caspase cascades as well as mitochondrial dysfunction.

• 대한약학회:학술대회논문집
• /
• 대한약학회 2002년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.2
• /
• pp.319.1-319.1
• /
• 2002

Yomogin. an eudesmane sesquiterpene isolated from Artemisia princeps, was found to induce apoptosis in human promyelocytic leukaemia, HL -60 cell with characteristic apoptotic features like nuclear condensation, apoptotic body formation, flipping of membrane phosphatidylserine, release of mitochondrial cytochrome c and caspase-8. -9. and -3 activation. Furthermore. early yomogin-induced cytochrome c release was not affected by the caspase inhibitor Z-VAd fmk and preceded loss of mitochondrial membrane potential. The results suggest that induction of apoptosis by yomogin may provide a pivotal mechanism for their cancer chemopreventive function.

• Journal of Korean Neurosurgical Society
• /
• 제59권3호
• /
• pp.259-268
• /
• 2016

Objective : Accumulation of advanced glycation end-products (AGE) and mitochondrial glycation is importantly implicated in the pathological changes of the brain associated with diabetic complications, Alzheimer disease, and aging. The present study was undertaken to determine whether sildenafil, a type 5 phosphodiesterase type (PDE-5) inhibitor, has beneficial effect on neuronal cells challenged with AGE-induced oxidative stress to preserve their mitochondrial functional integrity. Methods : HT-22 hippocampal neuronal cells were exposed to AGE and changes in the mitochondrial functional parameters were determined. Pretreatment of cells with sildenafil effectively ameliorated these AGE-induced deterioration of mitochondrial functional integrity. Results : AGE-treated cells lost their mitochondrial functional integrity which was estimated by their MTT reduction ability and intracellular ATP concentration. These cells exhibited stimulated generation of reactive oxygen species (ROS), disruption of mitochondrial membrane potential, induction of mitochondrial permeability transition, and release of the cytochrome C, activation of the caspase-3 accompanied by apoptosis. Western blot analyses and qRT-PCR demonstrated that sildenafil increased the expression level of the heme oxygenase-1 (HO-1). CoPP and bilirubin, an inducer of HO-1 and a metabolic product of HO-1, respectively, provided a similar protective effects. On the contrary, the HO-1 inhibitor ZnPP IX blocked the effect of sildenafil. Transfection with HO-1 siRNA significantly reduced the protective effect of sildenafil on the loss of MTT reduction ability and MPT induction in AGE-treated cells. Conclusion : Taken together, our results suggested that sildenafil provides beneficial effect to protect the HT-22 hippocampal neuronal cells against AGE-induced deterioration of mitochondrial integrity, and upregulation of HO-1 is involved in the underlying mechanism.

• BMB Reports
• /
• 제55권7호
• /
• pp.354-359
• /
• 2022

MitoNEET, a mitochondrial outer membrane protein containing the Asn-Glu-Glu-Thr (NEET) sequence, controls the formation of intermitochondrial junctions and confers autophagy resistance. Moreover, mitoNEET as a mitochondrial substrate undergoes ubiquitination by activated Parkin during the initiation of mitophagy. Therefore, mitoNEET is linked to the regulation of autophagy and mitophagy. Mitophagy is the selective removal of the damaged or unnecessary mitochondria, which is crucial to sustaining mitochondrial quality control. In numerous human diseases, the accumulation of damaged mitochondria by impaired mitophagy has been observed. However, the therapeutic strategy targeting of mitoNEET as a mitophagy-enhancing mediator requires further research. Herein, we confirmed that mitophagy is indeed activated by mitoNEET inhibition. CCCP (carbonyl cyanide m-chlorophenyl hydrazone), which leads to mitochondrial depolarization, induces mitochondrial dysfunction and superoxide production. This, in turn, contributes to the induction of mitophagy; mitoNEET protein levels were initially increased before an increase in LC3-II protein following CCCP treatment. Pharmacological inhibition of mitoNEET using mitoNEET Ligand-1 (NL-1) promoted accumulation of Pink1 and Parkin, which are mitophagy-associated proteins, and activation of mitochondria-lysosome crosstalk, in comparison to CCCP alone. Inhibition of mitoNEET using NL-1, or mitoNEET shRNA transfected into RAW264.7 cells, abrogated CCCP-induced ROS and mitochondrial cell death; additionally, it activated the expression of PGC-1α and SOD2, regulators of oxidative metabolism. In particular, the increase in PGC-1α, which is a major regulator of mitochondrial biogenesis, promotes mitochondrial quality control. These results indicated that mitoNEET is a potential therapeutic target in numerous human diseases to enhance mitophagy and protect cells by maintaining a network of healthy mitochondria.

• 대한의생명과학회지
• /
• 제20권1호
• /
• pp.32-38
• /
• 2014

Potassium cyanate (KOCN) that is known as an inducer of the protein carbamylation is an inorganic compound and is the conjugate based of cyanic acid (HOCN). Based on these studies, we confirmed that KOCN induces the apoptosis of the human colorectal cancer cell line, HCT 116 cells, by various mitochondrial pathways. To investigate other mechanisms of KOCN-mediated apoptosis, in the present study, we examined KOCN-induced cytokines production in HCT 116 cells and identified the intracellular signaling pathway in these processes. We first demonstrated that KOCN considerably increased the cell apoptosis via intracellular $Ca^{2+}$ signaling, mitochondrial dysfunction and ROS production. And then we examined TNF-${\alpha}$ and IL-$1{\beta}$ levels mediated by KOCN in HCT 116 cells. Although IL-$1{\beta}$ was not involved in KOCN-mediated HCT 116 cell apoptosis, the release of TNF-${\alpha}$ was mediated by KOCN in HCT 116 cells via NF-${\kappa}B$ activation. Apoptosis was also enhanced by incubation with supernatants from HCT 116 cells after KOCN treatment and this effect was partially reduced by BAY 11-7085 pre-treated supernatant. Taken together, our results indicate that KOCN-induced apoptosis in HCT 116 cells is dependent on the releases of TNF-${\alpha}$ and the increased factors and that the mechanism involves the activation of NF-${\kappa}B$.

• 운동영양학회지
• /
• 제23권1호
• /
• pp.28-35
• /
• 2019

[Purpose] The purpose of this study was to investigate the effects of treadmill exercise on oxidative stress in the hippocampal tissue and mitochondrial dynamic-related proteins in rats fed a long-term high-fat diet (HFD). [Methods] Obesity was induced in experimental animals using high fat feed, and the experimental groups were divided into a normal diet-control (ND-CON; n=12), a high fat diet-control (HFD-CON; n=12) and a high fat diet-treadmill exercise (HFD-TE; n=12) group. The rats were subsequently subjected to treadmill exercise (progressively increasing load intensity) for 8 weeks (5 min at 8 m/min, then 5 min at 11 m/min, and finally 20 min at 14 m/min). We assessed weight, triglyceride (TG) concentration, total cholesterol (TC), area under the curve, homeostatic model assessment of insulin resistance, and AVF/body weight. Western blotting was used to examine expression of proteins related to oxidative stress and mitochondrial dynamics, and immunohistochemistry was performed to examine the immunoreactivity of gp91phox. [Results] Treadmill exercise effectively improved the oxidative stress in the hippocampal tissue, expression of mitochondrial dynamic-related proteins, and activation of NADPH oxidase (gp91phox) and induced weight, blood profile, and abdominal fat loss. [Conclusion] Twenty weeks of high fat diet induced obesity, which was shown to inhibit normal mitochondria fusion and fission functions in hippocampal tissues. However, treadmill exercise was shown to have positive effects on these pathophysiological phenomena. Therefore, treadmill exercise should be considered during prevention and treatment of obesity-induced metabolic diseases.