Chin-Chuan Su

China Medical University Hospital, 臺中市, Taiwan, Taiwan

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Publications (12)35.71 Total impact

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    ABSTRACT: Inflammation is a serious health issue worldwide that induces many diseases, such as inflammatory bowel disease (IBD), sepsis, acute pancreatitis and lung injury. Thus, there is a great deal of interest in new methods of limiting inflammation. In this study, we investigated the leaves of Nelumbo nucifera Gaertn, an aquatic perennial plant cultivated in eastern Asia and India, in anti-inflammatory pharmacological effects in the murine macrophage cell line RAW264.7. Results showed that lipopolysaccharide (LPS) increased the protein expression of inducible nitric oxide synthase (iNOS) and COX-2, as well as the mRNA expression and level of IL-6 and TNF-α, while NNE significantly reduced these effects of LPS. LPS also induced phospho-JNK protein expression. The JNK-specific inhibitor SP600125 decreased the proteins expression of phospho-JNK, iNOS, COX-2, and the mRNAs expression and levels of IL-6 and TNF-α. Further, NNE reduced the protein expression of phospho-JNK. LPS was also found to promote the translocation of NF-κB from the cytosol to the nucleus and to decrease the expression of cytosolic IκB. NNE and SP600125 treatment recovered the LPS-induced expression of NF-κB and IκB. While phospho-ERK and phospho-p38 induced by LPS, could not be reversed by NNE. To further investigate the major components of NNE in anti-inflammatory effects, we determined the quercetin and catechin in inflammatory signals. Results showed that quercetin and catechin significantly decreased the proteins expression of iNOS, COX-2 and phospho-JNK. Besides, the mRNAs and levels of IL-6 and TNF-α also decreased by quercetin and catechin treatment in LPS-induced RAW264.7 cells. These results showed that NNE and its major components quercetin and catechin exhibit anti-inflammatory activities by inhibiting the JNK- and NF-κB-regulated pathways and could therefore be an useful anti-inflammatory agent.
    The American journal of Chinese medicine. 01/2014; 42(4):869-89.
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    ABSTRACT: Arsenic (As), a well-known high toxic metal, is an important environmental and industrial contaminant, and it induces oxidative stress, which causes many adverse health effects and diseases in humans, particularly in inorganic As (iAs) more harmful than organic As. Recently, epidemiological studies have suggested a possible relationship between iAs exposure and neurodegenerative disease development. However, the toxicological effects and underlying mechanisms of iAs-induced neuronal cell injuries are most unknown. The present study demonstrated that iAs significantly decreased cell viability and induced apoptosis in Neuro-2a cells. iAs also increased oxidative stress damage (production of malondialdehyde (MDA) and ROS, and reduction of Nrf2 and thioredoxin protein expression) and induced several features of mitochondria-dependent apoptotic signals, including: mitochondrial dysfunction, the activations of PARP and caspase cascades, and the increase in caspase-3 activity. Pretreatment with the antioxidant N-acetylcysteine (NAC) effectively reversed these iAs-induced responses. iAs also increased the phosphorylation of JNK and ERK1/2, but did not that p38-MAPK, in treated Neuro-2a cells. NAC and the specific JNK inhibitor (SP600125) and ERK1/2 inhibitor (PD98059) abrogated iAs-induced cell cytotoxicity, caspase-3/-7 activity, and JNK and ERK1/2 activation. Additionally, exposure of Neuro-2a cells to iAs triggered endoplasmic reticulum (ER) stress identified through several key molecules (GRP 78, CHOP, XBP-1, and caspase-12), which was prevented by NAC. Transfection with GRP 78- and CHOP-specific si-RNA dramatically suppressed GRP 78 and CHOP expression, respectively, and attenuated the activations of caspase-12, -7, and -3 in iAs-exposed cells. Therefore, these results indicate that iAs induces ROS causing neuronal cell death via both JNK/ERK-mediated mitochondria-dependent and GRP 78/CHOP-triggered apoptosis pathways.
    Toxicology Letters 10/2013; · 3.15 Impact Factor
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    ABSTRACT: Cadmium (Cd), one of well-known highly toxic environmental and industrial pollutants, causes a number of adverse health effects and diseases in humans. The growing epidemiological studies have suggested a possible link between Cd exposure and diabetes mellitus (DM). However, the toxicological effects and underlying mechanisms of Cd-induced pancreatic β-cell injury are still unknown. In this study, we found that Cd significantly decreased cell viability, and increased sub-G1 hypodiploid cells and annexin V-Cy3 binding in pancreatic β-cell-derived RIN-m5F cells. Cd also increased intracellular reactive oxygen species (ROS) generation and malondialdehyde (MDA) production and induced mitochondrial dysfunction (the loss of mitochondrial membrane potential (MMP) and the increase of cytosolic cytochrome c release), the decreased Bcl-2 expression, increased p53 expression, poly (ADP-ribose) polymerase (PARP) cleavage, and caspase cascades, which accompanied with intracellular Cd accumulation. Pretreatment with the antioxidant N-acetylcysteine (NAC) effectively reversed these Cd-induced events. Furthermore, exposure to Cd induced the phosphorylations of c-jun N-terminal kinases (JNK), extracellular signal-regulated kinases (ERK)1/2, and p38-mitogen-activated protein kinase (MAPK), which was prevented by NAC. Additionally, the specific JNK inhibitor SP600125 or JNK-specific small interference RNA (si-RNA) transfection suppressed Cd-induced β-cell apoptosis and related signals, but not ERK1/2 and p38-MAPK inhibitors (PD98059 and SB203580) did not. However, the JNK inhibitor or JNK-specific si-RNA did not suppress ROS generation in Cd-treated cells. These results indicate that Cd induces pancreatic β-cell death via an oxidative stress downstream-mediated JNK activation-triggered mitochondria-regulated apoptotic pathway.
    PLoS ONE 01/2013; 8(2):e54374. · 3.73 Impact Factor
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    ABSTRACT: Chloroacetic acid (CA), a toxic chlorinated analog of acetic acid, is widely used in chemical industries as an herbicide, detergent, and disinfectant, and chemical intermediates that are formed during the synthesis of various products. In addition, CA has been found as a by-product of chlorination disinfection of drinking water. However, there is little known about neurotoxic injuries of CA on the mammalian, the toxic effects and molecular mechanisms of CA-induced in neuronal cells are mostly unknown. In this study, we examined the cytotoxicity of CA on cultured Neuro-2a cells and investigated the possible mechanisms of CA-induced neurotoxicity. Treatment of Neuro-2a cells with CA significantly reduced the number of viable cells (in a dose-dependent manner with a range from 0.1 to 3mM), increased the generation of ROS, and reduced the intracellular levels of glutathione depletion. CA also increased the number of sub-G1 hypodiploid cells; increased mitochondrial dysfunction (loss of MMP, cytochrome c release, and accompanied by Bcl-2 and Mcl-1 down-regulation and Bax up-regulation), and activated the caspase cascades activations, which displayed features of mitochondria-dependent apoptosis pathway. These CA-induced apoptosis-related signals were markedly prevented by the antioxidant N-acetylcysteine (NAC). Moreover, CA activated the JNK and p38-MAPK pathways, but did not that ERK1/2 pathway, in treated Neuro-2a cells. Pretreatment with NAC and specific p38-MAPK inhibitor (SB203580), but not JNK inhibitor (SP600125) effectively abrogated the phosphorylation of p38-MAPK and attenuated the apoptotic signals (including: decrease in cytotoxicity, caspase-3/-7 activation, the cytosolic cytochrome c release, and the reversed alteration of Bcl-2 and Bax mRNA) in CA-treated Neuro-2a cells. Taken together, these data suggest that oxidative stress-induced p38-MAPK activated pathway-regulated mitochondria-dependent apoptosis plays an important role in CA-caused neuronal cell death.
    Toxicology 10/2012; · 4.02 Impact Factor
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    ABSTRACT: Paraquat (1,1'-dimethyl-4,4'-bipyridinium chloride; PQ) is widely and commonly used as a herbicides in the world. PQ has been reported to be a major hazard because it causes lung injury. However, the molecular mechanisms underlying PQ-induced lung toxicity still need to be elucidated. Here, we found that PQ significantly decreases cell viability, increases sub-G1 hypodiploids DNA contents and caspase 3/7 activity in lung alveolar epithelial cell-derived L2 cells, which also caused mitochondrial dysfunction, and decreased the mRNA expression of Bcl-2 and increased that of Bax, Bak, and p53. Moreover, the protein expressions of Bax and Bak were increased in PQ-treated cells. In addition, when PQ was exposed to L2 cells, the expressions of ER stress-related signaling genes (including Grp78, CHOP, and caspase-12 mRNA) and proteins (including phospho-eIF-2α, CHOP, Grp78, calpain I and -II, and caspase-12) were significantly increased. PQ also decreased the protein expressions of pro-caspase-9/7/3. Next, we investigated the role of Nrf-2 in PQ-induced alveolar epithelial cell toxicity. In L2 cells, PQ induced Nrf-2 translocation from the cytosol to the nucleus. Cells transfected with Nrf-2 siRNA significantly reversed the PQ-induced toxicity, including depolarization of MMP, increased the Bax, Bak, p53 mRNAs expression, decreased the Bcl-2 mRNA expression, increased the caspase 3/7 activity, Grp78, CHOP, and caspase-12 mRNAs and protein expression, and decreased that of pro-caspase-3. Taken together, these results suggest that Nrf-2-regulated mitochondria and ER stress-related pathways are involved in the PQ-induced alveolar epithelial cell injury.
    Archives of Toxicology 06/2012; 86(10):1547-58. · 5.22 Impact Factor
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    ABSTRACT: Mercury is a toxic heavy metal that is an environmental and industrial pollutant throughout the world. Mercury exposure leads to many physiopathological injuries in mammals. However, the precise toxicological effects of mercury on pancreatic islets in vivo are still unclear. Here, we investigated whether mercuric compounds can induce dysfunction and damage in the pancreatic islets of mice, as well as the possible mechanisms involved in this process. Mice were treated with methyl mercuric chloride (MeHgCl, 2 mg/kg) and mercuric chloride (HgCl(2), 5 mg/kg) for more than 2 consecutive weeks. Our results showed that the blood glucose levels increased and plasma insulin secretions decreased in the mice as a consequence of their exposure. A significant number of TUNEL-positive cells were revealed in the islets of mice that were treated with mercury for 2 consecutive weeks, which was accompanied by changes in the expression of the mRNA of anti-apoptotic (Bcl-2, Mcl-1, and Mdm-2) and apoptotic (p53, caspase-3, and caspase-7) genes. Moreover, plasma malondialdehyde (MDA) levels increased significantly in the mice after treatment with mercuric compounds for 2 consecutive weeks, and the generation of reactive oxygen species (ROS) in the pancreatic islets also markedly increased. In addition, the mRNA expression of genes related to antioxidation, including Nrf2, GPx, and NQO1, were also significantly reduced in these islets. These results indicate that oxidative stress injuries that are induced by mercuric compounds can cause pancreatic islets dysfunction and apoptosis in vivo.
    International Journal of Molecular Sciences 01/2012; 13(10):12349-66. · 2.46 Impact Factor
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    ABSTRACT: Oxidative stress was demonstrated to promote the progression of diabetes mellitus (DM). It has been suggested that copper may play a specific role in the progression and pathogenesis of DM. Pyrrolidine dithiocarbamate (PDTC), a widely apply to the medicine, was known to be capable of enhancing copper accumulation. In this study, we investigated the effect of submicromolar-concentration Cu(2+)/PDTC complex on pancreatic β-cell damage and evaluated the role of oxidative stress in this effect. CuCl(2) (0.01-300μM) did not affect the cell viability in β-cell line RIN-m5F cells. However, combination of CuCl(2) (0.5μM) and PDTC (0.3μM) markedly reduced RIN-m5F cell viability. Cu(2+)/PDTC complex could also increase the LPO and decrease the intracellular reduced GSH levels, and display several features of apoptosis signals including: increase in sub-G1 cell population, annexin-V binding, and caspase-3 activity, mitochondrial dysfunctions, and the activation of PARP and caspase cascades, which accompanied with the marked increase the intracellular Cu(2+) levels. These apoptotic-related responses of Cu(2+)/PDTC complex-induced could be effectively prevented by antioxidant N-acetylcysteine (NAC). Furthermore, Cu(2+)/PDTC complex was capable of increasing the phosphorylations of ERK1/2 and JNK, and its upstream kinase MEK1/2 and MKK4, which could be reversed by NAC. Transfection with ERK2- and JNK-specific si-RNA and specific inhibitors SP600125 and PD98059 could inhibit ERK1/2 and JNK activation and attenuate MMP loss and caspase-3 activity induced by the Cu(2+)/PDTC complex. Taken together, these results are the first report to demonstrate that the Cu(2+)/PDTC complex triggers a mitochondria-regulated apoptosis via an oxidative stress-induced ERK/JNK activation-related pathway in pancreatic β-cells.
    Toxicology Letters 11/2011; 208(3):275-85. · 3.15 Impact Factor
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    ABSTRACT: Nickel (Ni), a well-known toxic metal, is widely used in electroplating and alloy production. It is also significantly implicated in industrial and environmental pollution caused by uncontrolled industrial and municipal discharges. In this study, we characterized and investigated the cytotoxic effects of Ni exposure and their probable toxicological mechanisms in the pancreatic β-cells. The results showed that it was significantly decreased cell viability after exposing pancreatic β-cell-derived RIN-m5F cells to NiCl(2) for 24h in a dose-dependent manner. NiCl(2) also increased sub-G1 hypodiploid cells and Annexin V-Cy3 binding population in RIN-m5F cells, indicating that it has apoptosis-inducing ability. Moreover, the exposure of RIN-m5F cells to NiCl(2) induced distinct signals of mitochondria-dependent apoptosis, including mitochondrial dysfunction (the disruption of mitochondrial membrane potential (MMP) and increase in mitochondrial cytochrome c release into the cytosol), Bak and Bid mRNA up-regulation, and activation of caspase-3, caspase-7, and caspase-9, and poly(ADP-ribose) polymerase (PARP) degradation. In addition, NiCl(2) also markedly induced the activation of c-Jun N-terminal kinases (JNK), but not of extracellular signal-regulated kinase (ERK)1/2 and p38. These NiCl(2)-induced apoptosis-related signaling responses could be effectively reversed by specific JNK inhibitor SP600125. To the best of our knowledge, this study is the first to show that Ni causes pancreatic β-cell death through a JNK activation-regulated mitochondria-dependent apoptosis-signaling pathway.
    Toxicology 08/2011; 289(2-3):103-11. · 4.02 Impact Factor
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    ABSTRACT: The objectives of this paper are to evaluate the heterogeneity of magnetic resonance imaging (MRI)-derived tumor thickness within tumors of the same T4a-staged tongue carcinoma and to elucidate the effects of tumor thickness on treatment outcomes. A sequential and prospectively maintained head and neck cancer database was retrospectively searched for newly diagnosed tongue carcinoma treated with surgery between 2003 and 2006. Fifty-eight patients with newly diagnosed T4a-staged tongue carcinoma were included in this study. Tumor thickness was obtained from preoperative magnetic resonance imaging. The mean MRI-derived tumor thickness was 22.29 mm. The patients with long tumor thickness (>26 mm) were associated with a significantly poor disease-specific survival (P = 0.015). The 2-year disease-specific survival rates were 72% in patients with short tumor thickness and only 27% in patients with long tumor thickness within the same T4a-staged disease. A substantial variation in MRI-derived tumor thickness was present within the same T4a-staged tongue carcinoma, and tumor thickness represented an important prognostic factor.
    Archives of Oto-Rhino-Laryngology 07/2011; 269(3):959-63. · 1.29 Impact Factor
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    ABSTRACT: Arsenic (As), a ubiquitous toxic metal, is an important environmental and industrial pollutant throughout the world. Inorganic As (iAs) is usually more harmful than organic ones and with a high risk of diabetes incidence by exposure. However, the toxicological effects of iAs on growth and function of pancreatic β-cells still remain unclear. Here, we found that iAs significantly decreased insulin secretion and cell viability, and increased ROS and MDA formation in pancreatic β-cell-derived RIN-m5F cells. iAs also induced the increases in sub-G1 hypodiploids, annexin V-Cy3 binding, and caspase-3 activity in RIN-m5F cells, indicating that iAs could induce β-cell apoptosis. Moreover, iAs induced MAPKs activation, mitochondria dysfunction, p53 up-regulation, Bcl-2 and Mdm-2 down-regulation, PARP, and caspase cascades, which displayed features of mitochondria-dependent apoptotic signals. In addition, exposure of RIN-m5F cells to iAs, could trigger ER stress as indicated by the enhancement in ER stress-related molecules induction (such as GRP78, GRP94, CHOP, and XBP1), procaspase-12 cleavage, and calpain activation. The iAs-induced apoptosis and its-related signalings could be effectively reversed by antioxidant N-acetylcysteine. We next observed that exposure of mice to iAs in drinking water for 6 consecutive weeks significantly decreased decreased the plasma insulin, elevated glucose intolerance and plasma lipid peroxidation, and induced islet cells apoptosis, which accompanied with arsenic accumulation in the whole blood and pancreas. N-acetylcysteine effectively antagonized the iAs-induced responses in mice. Taken together, these results suggest that iAs-induced oxidative stress causes pancreatic β-cells apoptosis via the mitochondria-dependent and ER stress-triggered signaling pathways.
    Toxicology Letters 02/2011; 201(1):15-26. · 3.15 Impact Factor
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    ABSTRACT: Pyrrolidine dithiocarbamate (PDTC) is widely used in pesticides, fungicides, insecticides, and herbicides. Copper (Cu) is a toxic heavy metal in the environment, and an essential trace metal element in the body, which is involved in many biological processes as a catalytic cofactor. The present study is designed to investigate the cellular toxicity of PDTC, CuCl(2), and PDTC/Cu complex exposure in lung alveolar epithelial cells that serve primary structural and functional roles in the lungs. The results showed that PDTC or CuCl(2) alone did not affect cell viability, but PDTC/Cu complex significantly decreased lung alveolar epithelial cell viability. PDTC/Cu complex also significantly increased intracellular copper concentration, but PDTC or CuCl(2) alone had low levels of copper. PDTC/Cu complex dramatically enhanced the JNK protein phosphorylation and ERK protein phosphorylation proteins. PDTC/Cu complex did not affect the p38 protein phosphorylation. PDTC/Cu complex was capable of activating the apoptosis-related caspases including caspase-9, caspase-7, and caspase-3, which could be reversed by the addition of JNK inhibitor SP600125 or transfection of MAPK8 short hairpin RNA. PDTC/Cu complex also increased cytosolic cytochrome c and decreased mitochondrial transmembrane potential. The Bcl-2 mRNA and protein expressions were decreased in lung epithelial cells treated with PDTC/Cu complex, which could be reversed by SP600125. Furthermore, PDTC/Cu complex could trigger the expressions of ER stress-associated signaling molecules including Grp78, Grp94, caspase-12, ATF4, and CHOP, which could be reversed by SP600125. Taken together, these results indicate that exposure to PDTC/Cu complex induces cytotoxicity and apoptosis in alveolar epithelial cells via the mitochondria- and ER-stress-related signaling pathways.
    Toxicology Letters 10/2010; 199(3):333-40. · 3.15 Impact Factor
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    ABSTRACT: Allergic rhinitis is a very common chronic disease. The purpose of this study was to measure the outcome of treating allergic rhinitis with diode laser, over a long-term follow-up of 6 years. Forty-two consecutive patients with newly diagnosed allergic rhinitis that was refractive to conservative medical therapies were enrolled in the study. Treatment was with a diode laser (wavelength 805 nm, laser parameter 12 W, in 'contact' mode) under local anesthesia between September 1999 and May 2000. A quality of life questionnaire was used after a follow-up period of 6 years to assess the outcome of diode laser surgery. All 42 patients suffered from either perennial or persistent-type allergic rhinitis. Twenty-five out of 42 patients (60%) replied to the questionnaire 6 years after laser surgery. The mean operation time was 1 min 28 s for each patient. No complications were observed (e.g., major bleeding), and no nasal packing was necessary. Statistical analysis revealed significant improvements in symptom score, medication score and total score 6 years after laser surgery. A total of 60% of the patients described improvements in symptom scores, and 68% of the patients described improvements in total score 6 years after laser treatment. It was evident that the effectiveness of laser surgery persisted through the 6 years of follow-up. Long-term follow-up after 6 years confirmed that diode laser surgery for allergic rhinitis is a useful procedure that has a long-lasting effect and can be performed in an outpatient surgery under local anesthesia. Minimal discomfort, long-term effectiveness and short operation time are other reasons why this treatment should be selected for patients with allergic rhinitis that is refractive to conservative management.
    Lasers in Medical Science 05/2008; 24(2):230-3. · 2.40 Impact Factor