• IMMUNE NETWORK
• /
• v.12 no.6
• /
• pp.284-290
• /
• 2012

Innate immune cells sense and respond to the cytoplasmic infection of bacterial pathogens through NLRP3, NLRC4 or AIM2 inflammasome depending on the unique molecular pattern of invading pathogens. The infection of flagellin- or type III secretion system (T3SS)-containing Gram-negative bacteria such as Salmonella enterica serovar Typhimurium (S. typhimurium) or Pseudomonas aeruginosa (P. aeruginosa) triggers NLRC4-dependent caspase-1 activation leading to the secretion of proinflammatory cytokines such as interleukin-1-beta (IL-$1{\beta}$) and IL-18. Previous studies have shown that apoptosis-associated speck-like protein containing a CARD (ASC) is also required for Salmonella-induced caspase-1 activation, but it is still unclear how ASC contributes to the activation of NLRC4 inflammasome in response to S. typhimurium infection. In this study, we demonstrate that S. typhimurium triggers the formation of ASC oligomer in a potassium depletion-independent manner as determined by in vitro crosslinking and in situ fluorescence imaging. Remarkably, inhibition of potassium efflux failed to block Salmonella-promoted caspase-1 activation and macrophage cell death. These results collectively suggest that ASC is substantially oligomerized to facilitate the activation of caspase-1 in response to S. typhimurium infection. Contrary to NLRP3 inflammasome, intracellular potassium depletion is not critical for NLRC4 inflammasome signaling by S. typhimurium.

• Journal of Life Science
• /
• v.27 no.3
• /
• pp.267-274
• /
• 2017

The patient with end-stage renal disease show several nervous complications. The factors contributing to the nervous complications are still incompletely characterized. Cyanate, known as one of the uremic toxins, is derived spontaneously from urea. To investigate the mechanism of cyanate-induced effect on C6 glioma cells, the glioma cells were treated with 0, 1, 5, 10, 20 and 40 mM cyanate. There was a dose-dependent decrease in cell viability and the decreased number of cell was observed in glioma cells by treatment with cyanate. Western blot showed the down- regulation of procaspase-3, which means up-regulation of caspase-3, and the up-regulation of caspase-8, but the down-regulation by cyanate. In addition, cDNA microarray showed 934 down-regulated genes and 165 up-regulated genes on 1,099 genes in cyanate treated group. Treatment with cyanate led to 16 down-regulated genes and 6 up-regulated genes on apoptosis category, and especially heat shock 70 kD protein 1A gene on the category of apoptosis was significantly up-regulated. These results suggest that cyanate can induce apoptosis through caspase-8 and caspase-3 in glioma cells and decrease of gene expression including apoptosis category in glioma cells. These effects of cyanate may play a role in the nervous complications of patient with end-stage renal disease.

• Biomolecules & Therapeutics
• /
• v.31 no.5
• /
• pp.526-535
• /
• 2023

Breast cancer is the most common cancer and a frequent cause of cancer-related deaths among women wordlwide. As therapeutic strategies for breast cancer have limitations, novel chemotherapeutic reagents and treatment strategies are needed. In this study, we investigated the anti-cancer effect of synthetic homoisoflavane derivatives of cremastranone on breast cancer cells. Homoisoflavane derivatives, SH-17059 and SH-19021, reduced cell proliferation through G2/M cell cycle arrest and induced caspase-independent cell death. These compounds increased heme oxygenase-1 (HO-1) and 5-aminolevulinic acid synthase 1 (ALAS1), suggesting downregulation of heme. They also induced reactive oxygen species (ROS) generation and lipid peroxidation. Furthermore, they reduced expression of glutathione peroxidase 4 (GPX4). Therefore, we suggest that the SH-17059 and SH-19021 induced the caspase-independent cell death through the accumulation of iron from heme degradation, and the ferroptosis might be one of the potential candidates for caspase-independent cell death.

• Journal of Photoscience
• /
• v.9 no.2
• /
• pp.509-511
• /
• 2002

In this study, we investigated apoptotic cell death induced by photodynamic therapy using 5-aminolaevulinic acid (ALA-PDT) in human promyelocytic leukemia cells (HL-60). ALA-PDT induced apoptosis in HL-60 cells as confirmed by DNA agarose gel electrophoresis and nuclear staining with Hoechst 33342. The apoptotic cell death was inhibited by addition of broad-spectrum caspase inhibitor Z-Asp-CH$_2$-DCB, indicating that the apoptotic cell death was induced in a caspase-dependent manner. Actually, western blotting analysis revealed that caspase-3 was processed as early as 1.5 h after ALA-PDT. Cytoplasmic cytochrome c released from mitochondria was detected by western blotting. However, inhibitor of caspase-9, a cysteine protease located in the downstream of cytochrome c release, was not able to reduce the apoptotic cell death. Therefore, the mitochondrial apoptotic pathway was not involved in the ALA-PDT-induced apoptosis. On the other hand, it was found that ALA-PDT-induced apoptosis was clearly inhibited by pretreatment of caspase-8 inhibitor. These data suggest that caspase-8-mediated apoptotic pathway is important in ALA-PDT-induced cell death.

• BMB Reports
• /
• v.35 no.1
• /
• pp.19-23
• /
• 2002

• Journal of Life Science
• /
• v.20 no.9
• /
• pp.1409-1414
• /
• 2010

The aim of this study was to investigate the effects of exercise on intrinsic and extrinsic apoptosis signaling pathways in skeletal muscle. ICR-type white male mice were divided into a control group (CON: n=10) and an exercise training group (EX: n=10) after a 1 week adaptation period. EX performed treadmill running at 16.4 m/min with a 4% incline, 40 min/day and 5 days/week for 8 weeks. Cervical dislocation was performed at 48 hours after the last bout of exercise, after which gastrocnemius skeletal muscles were immediately collected. The results of verifying the intrinsic apoptosis pathway showed that there were no significant differences in Bcl-2, Bax, or the ratio of Bax/Bcl-2 proteins between EX and CON. On the other hand, the results of verifying the extrinsic apoptosis pathway showed that caspase-8 proteins were significantly lower in EX than in CON (p<0.05). Apoptosis suppressing protein HSP70 was higher in EX than in CON. In addition, caspase-3, which is the final factor for apoptosis, was not activated. These results indicate that apoptosis did not develop since caspase-3 is non-cleaved by the effects of caspase-8 and HSP70 extrinsic pathways rather than Bcl-2 and Bax intrinsic pathways among signal pathways for apoptosis.

• BMB Reports
• /
• v.35 no.1
• /
• pp.24-27
• /
• 2002

Apoptotic cell death is an active process mediated by various signaling pathways, which include the caspase cascade and the stress-activated protein kinase pathways. The caspase cascade is activated by two distinct routes: one from cell surface and the other from mitochondria. Activation of the route from cell surface requires the cellular components that include membrane receptors, adaptor proteins such as TRADD and FADD, and caspase-8, while activation of the other from mitochondria requires Apaf-1, caspase-9, and cytosolic cytochrome c. On the other hand, persistent stimulation of the stress-activated protein kinase pathway is also shown to mediate apoptosis in many cell types. Gene-targeting studies with jnk- or jip-null mice, in particular, strongly suggest that this signaling pathway plays a pivotal role in the cellular machinery for apoptosis.

• Proceedings of the PSK Conference
• /
• 2003.10b
• /
• pp.107.1-107.1
• /
• 2003

20-O-(${\beta}$-D-Glucopyranosyl)-20(S)-protopanaxadiol (IH901), an intestinal bacterial metabolite of ginseng saponins formed from ginsenosides Rb1, Rb2 and Rc, is suggested to be a potential chemopreventive agent. Here we show that IH901 induces apoptosis in human hepatoblastoma HepG2 cells. IH901 led to an early activation of procaspase-3 (6 h posttreatment), and the activation of caspase-8 became evident only later (18 h posttreatment). Caspase activation was a necessary requirement for apoptosis because caspase inhibitors significantly inhibited cell death by IH901. (omitted)

• IMMUNE NETWORK
• /
• v.20 no.5
• /
• pp.39.1-39.13
• /
• 2020

Sjögren's syndrome (SS) is a chronic and systemic autoimmune disease characterized by lymphocytic infiltration in the exocrine glands. In SS, type I IFN has a pathogenic role, and recently, inflammasome activation has been observed in both immune and non-immune cells. However, the relationship between type I IFN and inflammasome-associated pyroptosis in SS has not been studied. We measured IL-18, caspase-1, and IFN-stimulated gene 15 (ISG15) in saliva and serum, and compared whether the expression levels of inflammasome and pyroptosis components, including absent in melanoma 2 (AIM2), NLR family pyrin domain containing 3 (NLRP3), apoptosis-associated speck-like protein (ASC), caspase-1, gasdermin D (GSDMD), and gasdermin E (GSDME), in minor salivary gland (MSG) are related to the expression levels of type I IFN signature genes. Expression of type I IFN signature genes was correlated with mRNA levels of caspase-1 and GSDMD in MSG. In confocal analysis, the expression of caspase-1 and GSDMD was higher in salivary gland epithelial cells (SGECs) from SS patients. In the type I IFN-treated human salivary gland epithelial cell line, the expression of caspase-1 and GSDMD was increased, and pyroptosis was accelerated in a caspase-dependent manner upon inflammasome activation. In conclusion, we demonstrate that type I IFN may contribute to inflammasome-associated pyroptosis of the SGECs of SS patients, suggesting another pathogenic role of type I IFN in SS in terms of target tissue -SGECs destruction.

• Proceedings of the PSK Conference
• /
• 2002.10a
• /
• pp.325.2-325.2
• /
• 2002

We investigated the effect of bovine lactoferricin (Lfcin-B) on cell cycle regulation and caspase activation in tumor cells. Treatment with Lfcin-B resulted in the production of intracellular reactive oxygen species (ROS) during apoptosis of THP-1 cells. Biochemical analysis revealed that Lfcin-B-induced apoptosis. the cell cycle arrest and caspase activation were completely abrogated by addition of an antioxidant such as N-acetylcysteine(NAC). (omitted)