Poly adenosine diphosphate-ribosylation and neurodegenerative diseases / 浙江大学学报·医学版

The morbidity of neurodegenerative diseases are increased in recent years, however, the treatment is limited. Poly ADP-ribosylation (PARylation) is a post-translational modification of protein that catalyzed by poly(ADP-ribose) polymerase (PARP). Studies have shown that PARylation is involved in many neurodegenerative diseases such as stroke, Parkinson's diseases, Alzheimer's disease, amyotrophic lateral sclerosis and so on, by affecting intracellular translocation of protein molecules, protein aggregation, protein activity, and cell death. PARP inhibitors have showed neuroprotective efficacy for neurodegenerative diseases in pre-clinical studies and phase Ⅰ clinical trials. To find new PARP inhibitors with more specific effects and specific pharmacokinetic characteristics will be the new direction for the treatment of neurodegenerative diseases. This paper reviews the recent progress on PARylation in neurodegenerative diseases.

Precision Medicine, Artificial Intelligence, and Genomic Markers in Urology. Do we need to Tailor our Clinical Practice? / Medicina de precisión, inteligencia artificial y marcadores genómicos en urología. ¿Debemos cambiar nuestra práctica clínica?

Precision medicine plays a key role in urological oncology practice nowadays, with the breakthrough of the poly (ADP-ribose) polymerase inhibitors (PARPi), which play a critical role in different DNA damage repair (DDR) pathways, the immune checkpoint inhibitors, the genomic expression profiles and current genome manipulation-directed targeted therapy. Information and technology (IT) are set to change the way we assess and treat patients and should be reviewed and discussed. The aim of the present article is to demonstrate a detailed revision on precision medicine, including novel therapeutic targets, genomic markers, genomic stratification of urological patients, and the top-notch technological breakthroughs that could change our clinical practice We performed a review of the literature in four different databases (PubMed, Embase, Lilacs, and Scielo) on any information concerning prostate, bladder, kidney and urothelial cancer novel treatments with PARPi, immune checkpoint inhibitors (ICIs), targeted therapy with fibroblast growth factor receptor inhibitors (FGFRi), and theranostics with prostate-specific membrane antigen (PSMA) targeted monoclonal antibodies. Artificial intelligence, machine learning, and deep learning algorithm in urological practice were also part of the search. We included all articles written in English, published within the past 7 years, that discussed outstanding therapies and genomics in urological cancer and artificial intelligence applied to urology. Meanwhile, we excluded articles with lack of a clear methodology and written in any other language than English. One-hundred and twenty-six articles of interest were found; of these, 65 articles that presented novel treatments of urological neoplasms, discussed precision medicine, genomic expression profiles and biomarkers in urology, and latest deep learning and machine learning algorithms as well as the use of artificial intelligence in urological practice were selected. A critical review of the literature is presented in the present article. Urology is a constantly changing specialty with a wide range of therapeutic breakthroughs, a huge understanding of the genomic expression profiles for each urological cancer and a tendency to use cutting-edge technology to treat our patients. All of these major developments must be analyzed objectively, taking into account costs to the health systems, risks and benefits to the patients, and the legal background that comes with them. A critical analysis of these new technologies and pharmacological breakthroughs should be made before considering changing our clinical practice. Nowadays, research needs to be strengthened to help us improve results in assessing and treating our patients

La medicina de precisión juega un rol fundamental en la práctica clínica de la urologia oncológica en la actualidad, con el desarrollo de los inhibidores de la poli (ADP-ribosa) polimerasa (PARPi), que juegan un papel fundamental en las distintas vías del reparo del ADN dañado (RAD), los inhibidores del punto de chequeo inmune (ICI), los perfiles de expresión genómicos, y la terapia blanco-dirigida a la manipulación genómica. El desarrollo tecnológico y la informática están cambiando la forma como evaluamos y tratamos a los pacientes, y se debe discutir y revisar a detalle. El objetivo de este artículo es hacer una revisión detallada acerca de la medicina de precisión, genómica, y los avances tecnológicos en nuestro campo. Realizamos una revisión de la literatura en cuatro bases de datos diferentes (PubMed, Embase, Lilacs, y Scielo), buscando cualquier información relacionada con cáncer de próstata, vejiga, riñón y carcinoma urotelial, tratamientos novedosos con PARPi, ICI, terapia-blanco con inhibidores del receptor del factor de crecimiento de los fibroblastos (FGFRi) y teragnósticos con anticuerpos monoclonales dirigidos al antígeno de membrana específico de la próstata (AMEP). Inteligencia artificial, aprendizaje de máquinas y algoritmos de aprendizaje profundo en la práctica urológica también fueron revisados. Incluimos artículos escritos en inglés, publicados dentro de los últimos 7 años, que abordaran terapias novedosas y genómica en cáncer urológico e inteligencia artificial aplicada a la urología. Excluimos artículos con falta de una metodología adecuada y escritos en cualquier idioma diferente al inglés. En total, 126 artículos de interés fueron encontrados, y, de estos seleccionamos 65 artículos que reportaban tratamientos novedosos para neoplasias urológicas, discutían medicina de precisión y perfiles de expresión genómica y bio-marcadores en urología, algoritmos de aprendizaje profundo, aprendizaje de máquina, y el uso de inteligencia artificial en la práctica urológica. Se hizo una revisión crítica de la literatura que se presenta en este artículo. La urología es una especialidad constantemente en cambio, con un gran rango de avances terapéuticos, un gran conocimiento de los perfiles de expresión genómica para cada cáncer urológico, y una tendencia a utilizar tecnología de punta para estudiar y tratar a nuestros pacientes. Todos estos desarrollos se deben analizar objetivamente, y hay que tener en cuenta los costos al sistema de salud, los riesgos y beneficios para los pacientes, y el contexto legal que implica cada uno. Hasta la fecha, estos avances tecnológicos y farmacológicos se deben analizar con cautela antes de vernos en la posición de cambiar nuestra práctica clínica. Se debe fortalecer la investigación médica para mejorar los resultados en el tratamiento y abordaje de nuestros pacientes.

The Anti-fibrotic Effect of Nilotinib on Tenon's Capsule Fibroblasts in Vitro

PURPOSE: To evaluate the anti-fibrotic effects of nilotinib on the survival of cultured human Tenon's capsule fibroblasts (HTFs). METHODS: HTF primary cultures were obtained from samples following glaucoma surgery. Primarily cultured HTFs were exposed to 1, 5, 10, and 20 µM nilotinib for 24 hours. The effects of nilotinib on HTF proliferation and cell viability were determined using the 3-(4,5-dimethylthiazone-2-yl)-2,5-diphenyl tetrazolium (MTT) assay, and apoptosis was determined by flow cytometry using annexin-V/propidium iodide (PI) double staining. Apoptosis-related proteins were detected by western blotting. RESULTS: The MTT assay showed that nilotinib induced an inhibition of HTF proliferation at concentrations of 10 and 20 µM (p < 0.001 and p < 0.001, respectively). Annexin V/PI double staining showed significantly increased apoptosis in cells treated with nilotinib. Nilotinib activated caspase-3, -9, and poly adenosine diphosphate ribose polymerase cleavage, and downregulated the expression of B-cell lymphoma-extra large and Bax, which indicated that nilotinib-induced apoptosis was partly mediated through the mitochondrial pathway. In addition, treatment with nilotinib decreased the expression of α-smooth muscle actin and transforming growth factor-β. CONCLUSIONS: Nilotinib decreased cell survival of cultured HTFs and induced mitochondria-mediated apoptosis. The results suggested that nilotinib may exert antiproliferative effects on HTFs, making it a possible agent to control postoperative fibrosis in patients undergoing glaucoma surgery.

Methanol Extracts of Codium fragile Induces Apoptosis through G1/S Cell Cycle Arrest in FaDu Human Hypopharynx Squamous Carcinoma Cells

Codium fragile (Suringar) Hariot is an edible green seaweed that belong to the Codiaceae family and has been used in Oriental medicine for the treatment of enterobiasis, dropsy, and dysuria. Methanol extract of codium fragile has anti-oxidant, anti-inflammatory and anti-cancer properties, although the anti-cancer effect on oral cancer has not yet been reported. In this study, we investigated the anti-cancer activity and the mechanism of cell death by methanol extracts of Codium fragile (MeCF) on human FaDu hypopharyngeal squamous carcinoma cells. Our data showed that MeCF inhibits cell viability in a dose-dependent manner, and markedly induced apoptosis, as determined by the MTT assay, Live/Dead assay, and DAPI stain. In addition, MeCF induced the proteolytic cleavage of procaspase −3, −7, −9 and poly(ADP-ribose) polymerase(PARP), and upregulated or downregulated the expression of mitochondrial-apoptosis factor, Bax(pro-apoptotic factor), and Bcl-2(anti-apoptotic factor), . Futhermore, MeCF induced a cell cycle arrest at the G1/S phase through suppressing the expression of the cell cycle cascade proteins, p21, CDK4, CyclinD1, and phospho-Rb. Taken together, these results indicated that MeCF inhibits cell growth, and this inhibition is mediated by caspase- and mitochondrial-dependent apoptotic pathways through cell cycle arrest at the G1/S phase in human FaDu hypopharyngeal squamous carcinoma cells. Therefore, methanol extracts of Codium fragile can be provided as a novel chemotherapeutic drug due to its growth inhibition effects and induction of apoptosis in human oral cancer cells.

Poly(ADP-ribose) polymerase 1 contributes to oxidative stress through downregulation of sirtuin 3 during cisplatin nephrotoxicity / 대한해부학회지

Enhanced oxidative stress is a hallmark of cisplatin nephrotoxicity, and inhibition of poly(ADP-ribose) polymerase 1 (PARP1) attenuates oxidative stress during cisplatin nephrotoxicity; however, the precise mechanisms behind its action remain elusive. Here, using an in vitro model of cisplatin-induced injury to human kidney proximal tubular cells, we demonstrated that the protective effect of PARP1 inhibition on oxidative stress is associated with sirtuin 3 (SIRT3) activation. Exposure to 400 µM cisplatin for 8 hours in cells decreased activity and expression of manganese superoxide dismutase (MnSOD), catalase, glutathione peroxidase (GPX), and SIRT3, while it increased their lysine acetylation. However, treatment with 1 µM PJ34 hydrochloride, a potent PARP1 inhibitor, restored activity and/or expression in those antioxidant enzymes, decreased lysine acetylation of those enzymes, and improved SIRT3 expression and activity in the cisplatin-injured cells. Using transfection with SIRT3 double nickase plasmids, SIRT3-deficient cells given cisplatin did not show the ameliorable effect of PARP1 inhibition on lysine acetylation and activity of antioxidant enzymes, including MnSOD, catalase and GPX. Furthermore, SIRT3 deficiency in cisplatin-injured cells prevented PARP1 inhibition-induced increase in forkhead box O3a transcriptional activity, and upregulation of MnSOD and catalase. Finally, loss of SIRT3 in cisplatin-exposed cells removed the protective effect of PARP1 inhibition against oxidative stress, represented by the concentration of lipid hydroperoxide and 8-hydroxy-2'-deoxyguanosine; and necrotic cell death represented by a percentage of propidium iodide–positively stained cells. Taken together, these results indicate that PARP1 inhibition protects kidney proximal tubular cells against oxidative stress through SIRT3 activation during cisplatin nephrotoxicity.

Poly(ADP-ribose) polymerase regulates glycolytic activity in kidney proximal tubule epithelial cells / 대한해부학회지

After renal injury, selective damage occurs in the proximal tubules as a result of inhibition of glycolysis. The molecular mechanism of damage is not known. Poly(ADP-ribose) polymerase (PARP) activation plays a critical role of proximal tubular cell death in several renal disorders. Here, we studied the role of PARP on glycolytic flux in pig kidney proximal tubule epithelial LLC-PK1 cells using XFp extracellular flux analysis. Poly(ADP-ribosyl)ation by PARP activation was increased approximately 2-fold by incubation of the cells in 10 mM glucose for 30 minutes, but treatment with the PARP inhibitor 3-aminobenzamide (3-AB) does-dependently prevented the glucose-induced PARP activation (approximately 14.4% decrease in 0.1 mM 3-AB-treated group and 36.7% decrease in 1 mM 3-AB-treated group). Treatment with 1 mM 3-AB significantly enhanced the glucose-mediated increase in the extracellular acidification rate (61.1±4.3 mpH/min vs. 126.8±6.2 mpH/min or approximately 2-fold) compared with treatment with vehicle, indicating that PARP inhibition increases only glycolytic activity during glycolytic flux including basal glycolysis, glycolytic activity, and glycolytic capacity in kidney proximal tubule epithelial cells. Glucose increased the activities of glycolytic enzymes including hexokinase, phosphoglucose isomerase, phosphofructokinase-1, glyceraldehyde-3-phosphate dehydrogenase, enolase, and pyruvate kinase in LLC-PK1 cells. Furthermore, PARP inhibition selectively augmented the activities of hexokinase (approximately 1.4-fold over vehicle group), phosphofructokinase-1 (approximately 1.6-fold over vehicle group), and glyceraldehyde-3-phosphate dehydrogenase (approximately 2.2-fold over vehicle group). In conclusion, these data suggest that PARP activation may regulate glycolytic activity via poly(ADP-ribosyl)ation of hexokinase, phosphofructokinase-1, and glyceraldehyde-3-phosphate dehydrogenase in kidney proximal tubule epithelial cells.

Leishmania, Babesia and Ehrlichia in urban pet dogs: co-infection or cross-reaction in serological methods?

INTRODUCTION: The present study was designed to assess the occurrence of co-infection or cross-reaction in the serological techniques used for detecting the anti-Leishmania spp., -Babesia canis vogeli and -Ehrlichia canis antibodies in urban dogs from an area endemic to these parasites. METHODS: The serum samples from dogs were tested for the Babesia canis vogeli strain Belo Horizonte antigen and Ehrlichia canis strain São Paulo by immunofluorescence antibody test (IFAT) and by anti-Leishmania immunoglobulin G (IgG) antibody detection to assess Leishmania infection. We used the following four commercial kits for canine visceral leishmaniasis: ELISA, IFAT, Dual Path Platform (DPP) (Bio Manguinhos(r)/FIOCRUZ/MS) and a rK39 RDT (Kalazar Detect Canine Rapid Test; Inbios). RESULTS : Of 96 serum samples submitted to serological assays, 4 (4.2%) were positive for Leishmania as determined by ELISA; 12 (12.5%), by IFAT; 14 (14.6%) by rK39 RDT; and 20 (20.8%), by DPP. Antibodies against Ehrlichia and Babesia were detected in 23/96 (23.9%) and 30/96 (31.2%) samples, respectively. No significant association was identified between the results of tests for detecting Babesia or Ehrlichia and those for detecting Leishmania (p-value>0.05). CONCLUSIONS: In the present study, we demonstrated co-infection with Ehrlichia or Babesia and Leishmania in dogs from Minas Gerais (Brazil); we also found that the serological tests that were used did not cross-react. .

Abnormal heart rate variability and atrial fibrillation after aortic surgery / Variabilidade anormal da frequência cardíaca e fibrilação atrial após cirurgia aórtica

Introduction: Complete denervation of transplanted heart exerts protective effect against postoperative atrial fibrillation; various degrees of autonomic denervation appear also after transection of ascending aorta during surgery for aortic aneurysm. Objective: This study aimed to evaluate if the level of cardiac denervation obtained by resection of ascending aorta could exert any effect on postoperative atrial fibrillation incidence. Methods: We retrospectively analysed the clinical records of 67 patients submitted to graft replacement of ascending aorta (group A) and 132 with aortic valve replacement (group B); all episodes of postoperative atrial fibrillation occurred during the 1-month follow-up have been reported. Heart Rate Variability parameters were obtained from a 24-h Holter recording; clinical, echocardiographic and treatment data were also evaluated. Results: Overall, 45% of patients (group A 43%, group B 46%) presented at least one episode of postoperative atrial fibrillation. Older age (but not gender, abnormal glucose tolerance, ejection fraction, left atrial diameter) was correlated with incidence of postoperative atrial fibrillation. Only among a subgroup of patients with aortic transection and signs of greater autonomic derangement (heart rate variability parameters below the median and mean heart rate over the 75th percentile), possibly indicating more profound autonomic denervation, a lower incidence of postoperative atrial fibrillation was observed (22% vs. 54%). Conclusion: Transection of ascending aorta for repair of an aortic aneurysm did not confer any significant protective effect from postoperative atrial fibrillation in comparison to patients with intact ascending aorta. It could be speculated that a limited and heterogeneous cardiac denervation was produced by the intervention, creating an eletrophysiological substrate for the high incidence of postoperative atrial fibrillation observed. .

Introdução: Denervação completa do coração transplantado exerce efeito protetor contra a fibrilação atrial no pós-operatório; vários graus de denervação autonômica aparecem também após a transecção da aorta ascendente durante a cirurgia de aneurisma da aorta. Objetivo: Este estudo teve como objetivo avaliar se o nível de denervação cardíaca obtida por ressecção da aorta ascendente poderia exercer algum efeito sobre a incidência de fibrilação atrial no pós-operatório. Métodos: Foram analisados retrospectivamente os prontuários de 67 pacientes submetidos a enxerto de substituição de aorta torácica (grupo A) e 132 com a substituição da valva aórtica (grupo B). Foram relatados todos os episódios de fibrilação atrial pós-operatória ocorridos durante 1 mês de seguimento. Parâmetros de variabilidade da frequência cardíaca foram obtidos a partir de 24 h de gravação do Holter; dados clínicos, ecocardiográficos e de tratamento também foram avaliados. Resultados: No geral, 45% dos pacientes (grupo A 43%, grupo B 46%) apresentaram pelo menos um episódio de fibrilação atrial no pós-operatório. Idade mais avançada (mas não gênero, tolerância à glicose anormal, fração de ejeção, diâmetro do átrio esquerdo) foi correlacionada com a incidência de fibrilação atrial pós-operatória. Apenas em um subgrupo de pacientes com transecção aórtica e sinais de maior desarranjo autonômico (parâmetros de variabilidade da frequência cardíaca abaixo da mediana e a média de frequência cardíaca acima do percentil 75), indicando possivelmente denervação autonômica mais profunda, foi observada menor incidência de fibrilação atrial pós-operatória (22% vs. 54%). Conclusão: Transecção da aorta ascendente para correção de um aneurisma da aorta não confere qualquer efeito protetor significativo de fibrilação atrial no pós-operatório em comparação com pacientes com aorta ascendente intacta. Pode-se especular que uma denervação cardíaca limitada e heterogênea foi produzida pela ...

Effect of poly-ADP-ribosylation on the alteration of DNA methylation level of human bronchial epithelial cells induced by Cr (VI) / 中华预防医学杂志

<p><b>OBJECTIVE</b>To reveal the role of poly-ADP-ribosylation and DNA methylation in carcinogenic process induced induced by Cr (VI), and to discuss the relations between them.</p><p><b>METHODS</b>The pre-established Poly (ADP-ribose) glycohydrolase (PARG) deficient cells and 16HBE cells were treated with different concentrations of Cr (VI), and the changes of total genomic DNA methylation level in different groups were detected by methylation immunofluorescent detection, as well as the changes of the activity of methyltransferases. Moreover, RT-PCR and western blotting method were applied to analyze the changes of expression of DNMT1, DNMT3a, DNMT3b and MBD2, upon the protein level.</p><p><b>RESULTS</b>After treated by Cr(VI) for 24 h, the healthy 16HBE cells showed a significant lower level of genomic DNA methylation; however, there was no significant changes (P > 0.05) found in PARG deficient cells by immunofluorescence assay. When the dose of Cr (VI) reached 5.0 µmol/L, the activity of methyltransferases in 16HBE cells and PARG deficient cells (49.33 ± 2.65, 80.05 ± 2.05) decreased by 20% and 50% comparing with contrast group (99.27 ± 1.10, 99.30 ± 0.60) . After treated by Cr (VI) for 24 h, the expression of mRNA and protein level among DNMT1, DNMT3a, DNMT3b and MBD2 decreased significantly in healthy 16HBE cells; and the expression of DNMT1 and DNMT3a decreased in PARG deficiency cells. The relevant expression levels of mRNA of DNMT1 were separately (0.99 ± 0.09), (0.79 ± 0.10), (0.59 ± 0.13) and (0.39 ± 0.02) (F = 247.17, P < 0.01), the expression levels of protein were separately (1.00 ± 0.03), (0.69 ± 0.15), (0.65 ± 0.10) and (0.55 ± 0.13) (F = 214.12, P < 0.01), the expression levels of DNMT3a mRNA were separately (1.00 ± 0.04) , (0.93 ± 0.11) , (0.79 ± 0.07) , (0.59 ± 0.05) (F = 498.16, P < 0.01) , and the expression levels of protein were separately (1.00 ± 0.14) , (0.97 ± 0.11) , (0.79 ± 0.17) , (0.57 ± 0.15) (F = 390.11, P < 0.01) when the dose of Cr (VI) at 0, 0.3, 1.2 and 5.0 µmol/L. However, there were no significant changes of expression found in DNMT3b and MBD2.</p><p><b>CONCLUSION</b>Poly-ADP-ribosylation could regulate the activity of DNMT3b and MBD2, protect cells against the DNA methylation alteration induced by Cr(VI) and maintain the global genomic DNA methylation level.</p>

The Role of Poly(ADP-ribose) Polymerase-1 in Ventilator-Induced Lung Injury / 결핵및호흡기질환

BACKGROUND: Reactive oxygen species (ROS) take center stage as executers in ventilator-induced lung injury (VILI). The protein with DNA-damage scanning activity, poly (ADP-ribose) polymerase-1 (PARP1), signals DNA rupture and participates in base-excision repair. Paradoxically,overactivation of PARP1 in response to massive genotoxic injury such as ROS can induce cell death through beta-nicotinamide adenine dinucleotide (NAD+) depletion, resulting in inflammation. The purpose of this study is to investigate the role of PARP1 and the effect of its inhibitor in VILI. METHODS: Forty-eight male C57BL/6 mice were divided into sham, lung protective ventilation(LPV), VILI, and PARP1 inhibitor (PJ34)+VILI (PJ34+VILI) groups. Mechanical ventilator setting for the LPV group was PIP 15 cmH2O + PEEP 3 cmH2O + RR 90/min + 2 hours. The VILI and PJ34+VILI groups were ventilated on a setting of PIP 40 cmH2O + PEEP 0 cmH2O + RR 90/min + 2 hours. As a PARP1 inhibitor for the PJ34+VILI group, 20 mg/Kg of PJ34 was treated intraperitoneally 2 hours before mechanical ventilation. Wet-to-dry weight ratio and acute lung injury (ALI) score were measured to determine the degree of VILI. PARP1 activity was evaluated by using an immunohistochemical method utilizing biotinylated NAD. Myeloperoxidase (MPO) activity and the concentration of inflammatory cytokines such as tumor necrosis factor (TNF)-alpha, interleukin (IL)-1beta, and IL-6 were measured in bronchoalveolar lavage fluid (BALF). RESULTS: In the PJ34+VILI group, PJ34 pretreatment significantly reduced the degree of lung injury, compared with the VILI group (p<0.05). The number of cells expressing PARP1 activity was significantly increased in the VILI group, but significantly decreased in the PJ34+VILI group (p=0.001). In BALF, MPO activity, TNF-alpha, IL-1beta, and IL-6 were also significantly lower in the PJ34+VILI group (all, p<0.05). CONCLUSION: PARP1 overactivation plays a major role in the mechanism of VILI. PARP1 inhibitor prevents VILI, and decreases MPO activity and inflammatory cytokines.

Increased Poly (ADP-ribose) Polymerase Activation in the 6-Hydroxydopamine Induced Dopaminergic Neuronal Cell Death

BACKGROUND: The pathological hallmark of Parkinson's disease (PD) is dopaminergic cell death in the substantia nigra (SN), but the cause of cell death is unknown. 6-Hydroxydopamine (6-OHDA) is one of the neurotoxins used in experimental models of PD, and its use has led to greater understanding of the pathogenesis of PD. The present study examined the role of poly(ADP-ribose) polymerase (PARP) in 6-OHDA toxicity. METHODS: An in-vitro study was performed using PC12 cells. After treatment with 6-OHDA, the poly(ADP-ribosyl) ation was monitored using a monoclonal antibody to poly(ADP-ribose) (PAR) to examine the PARP activity. To evaluate the effect of the PARP inhibition in 6-OHDA-induced cell death, 3-aminobenzamide or nicotinamide was administered 30 minutes before 6-OHDA treatment. An in-vivo study was performed using a Parkinson rat model. 6-OHDA was stereotactically injected into the unilateral SN of rats. PAR immunolabeling was used to examine the time-dependent activation of PARP. The dopaminergic cell death in the SN was quantified using apomorphine-induced rotations and tyrosine hydroxylase- immunoreactive cell numbers in the SN 2 weeks after lesioning. RESULTS: Poly(ADP-ribosyl)ation of nuclear proteins was maximal at 6 hr, and was still present 24 hr after 6-OHDA treatment. Pretreatment of 3-aminobenzamide or nicotinamide significantly attenuated the 6-OHDA-induced PC12 cell death. In 6-OHDA injected rats, PAR formation was seen 6 hr after 6-OHDA injection, peaked at 12 hr, and was still detectable at 24 hr. The dopaminergic cell death in the SN was significantly decreased by intraperitoneal injection of nicotinamide in 6-OHDA injected rats. CONCLUSIONS: These results provide evidence suggesting an involvement of the PARP in 6-OHDA-induced dopaminergic cell death, and inhibitors of PARP may have a protective benefit in PD.

Cisplatin-Induced Apoptosis by Cisplatin in Human Glioblastoma Cell Line

OBJECTIVE: This study is designed to evaluate the apoptotic signaling pathway of anticancer agent (cisplatin) on human malignant glioblastoma A172 and T98G cells, bearing wild type p53 and mutated p53, respectively. METHODS: The A172 and T98G glioblastoma cells were exposed to cisplatin and we investigated the cytotoxic effect in two different cell lines with cell viability(MTT assay), morphological study(agarose-gel electroporesis and Hoechst staining), and biochemical study(PCR, RT-PCR, Western blotting, caspase activity assay, and flow cytometry). RESULTS: Cisplatin had cytotoxicity of A172 cells in a time and dose-dependent manner. The nature of cytotoxicity by cisplatin was revealed as an apoptosis characterized by genomic DNA fragmentation in agarose electrophoresis as well as nuclear condensation by Hoechst staining in A172 cells. Cisplatin also resulted in the activation of caspase-9 and caspase 3-like proteases significantly, which eventually cleaved poly(ADP-ribose) polymerase(PARP) in A172 cells, but not in T98G cells. Interestingly, treatment with cisplatin was accumulated p21 and arrested cell cycle in A172 cells with time dependency. Furthermore, cisplatin-treated A172 cells resulted in change of membrane potential transition(MPT) of mitochondria and followed by cytosolic release of cytochrome c in time-dependent manner. In addition, transduction of ad-p53 significantly increased the cytotoxicity of cisplatin in T98G cells. CONCLUSION: Cisplatin induced apoptotic death of human glioblastoma A172 cells in p53 dependent manner. Furthermore, resistance of cisplatin in T98G cells, bearing mutated p53, was abolished by p53 protein expression and resulted in the apoptotic cell death.

Cadmium-induced Apoptosis in HL-60 Cells Via Signal Transduction / 대한산업의학회지

OBJECTIVES: Apoptosis is a process of active cell death, distinct from necrosis and characterized by specific morphological and biochemical features. Apoptosis induced by metals and metal-related deleterious conditions has only recently been studied. Although the toxic effects of heavy metals are well described, little is known about the mechanism of apoptosis via cadmium toxicity. Therefore, this study is designed to define the induction mechanism of apoptosis by which cadmium exerts its cytotoxic effect on human promyelocytic leukemic HL-60 cells. The cytotoxic effects of cadmium on HL-60 cells are studied in regards to apoptotic signal transduction pathways. METHODS: The mode of cadmium-induced apoptosis was investigated in HL-60 cells. HL-60 cells were treated with various concentrations of cadmium and antioxidants after which the viability of the cells were measured by MTT assay. The morphological features of cadmium- induced apoptosis were evaluated by fluoromicroscopy and the DNA fragmentation was analyzed using 1.5% agarose gel electrophorosis. Kinase activity was assayed by autoradiography and activity of NF-kappaB and nuclear proteins were measured by EMSA. RESULTS: Cadmium (125 microM) induces the characteristic morphological features of apoptosis, which are characterized by a shrinkage of the cytoplasm and a condensation of chromatin. In addition, cadmium induced the ladder pattern of DNA fragmentation. Antioxidants(Sodium nitroprusside, glutathione and N-acethylcysteine), which were not toxic to the cells, did not suppress apoptosis induced by cadmium. Cadmium enhances the expression of several classes of genes at elevated cytotoxic concentrations. Poly(ADP-ribose) polymerase(PARP) was predominantly in the fragmented form when doses of 125 microM were used. Since PARP is cleaved by CPP32 (caspase-3), we next determined if cadmium was capable of effecting changes in CPP32 activity. The results of these experiments showed that cadmium increased caspase-3 activity in a time dependent manner, corresponding to the time of appearance of fragmented PARP. Cadmium also increased the phosphotransferase activities of c-JUN N-terminal kinase (JNK). Furthermore, cadmium increased the activation of transcriptional factors including the activation of protein-1 (AP-1) and NF-kappaB . CONCLUSIONS: These results suggest that cadmium induces the apoptotic death of HL-60 cells via the activation of a DEVD-specific caspase, JNK and transcriptional factors such as AP-1 and NF-kappaB .

Neuroprotective Effect of N-acetylcysteine in an Asphyxial Cardiac Arrest Model of Rats

BACKGROUND: A major pathway leading toward neuronal injury following ischemia-reperfusion of the brain involves elevation of extracellular glutamate and activation of glutamate receptors, with a subsequent increase in intracellular calcium, resulting in a generation of free radicals. Oxygen free radicals cause brain injury following resuscitation from cardiac arrest. Oxyradicals produce strand breakage in DNA, which triggers energy-consuming DNA repair mechanisms and activates the nuclear enzyme poly(ADP-ribose) synthetase(PARS). However, excessive PARS activation leads to energy depletion and exacerbation of neuronal damage in cerebral ischemia. METHODS: We investigated the effect of a potent, free-radical scavenger, N-acetylcysteine(NAC), on hippocampal neuronal death in an asphyxial cardiac arrest model of rats. The effect of NAC on hippocampal neuronal death was studied in 32 rats which were subjected to asphyxial cardiac arrest for 7 minutes, followed by resuscitation. The animals were divided into four group(8 rats in each group) as follows: Group I was saline treated for 3 days, Group II was NAC treated for 3 days, Group III was saline treated for 6 days, and Group IV was NAC treated for 6 days. In the NAC-treated groups, NAC(150 mg/kg) was intravenously injected after return of spontaneous circulation. The coronal sections with hippocampus levels were stained with hematoxylin-eosin(H-E) and PARS antibodies at 3 and 6 days after survival. In addition, the levels of myeloperoxidase(MPO) and malondialdehyde(MDA) were determined in the brains of each group. RESULTS: The results are as follows: 1. MPO and MDA levels were significantly lower in the NAC-treated groups, II and IV, than in the saline-treated groups, I and III. 2. The histologic damage score(HDS), as determined by H-E staining, was significantly lower in the NAC-treated groups, II and IV, than in the saline-treated groups, I and III. 3. In PARS immunohistochemical staining, the HDS was significantly lower in the NAC-treated groups, II and IV, than in the saline-treated groups, I and III. CONCLUSION: These results suggest that a free-radical scavenger, N-acetylcysteine, may effectively prevent neuronal damages after reperfusion from asphyxial cardiac arrest in rats. Further studies will be required to examine both the mechanism of the action and the clinical application of NAC in patients with cardiac arrest.

Large-scale production and purification of recombinant protein from an insect cell/baculovirus system in Erlenmeyer flasks: application to the chicken poly(ADP-ribose) polymerase catalytic domain

A simple and inexpensive shaker/Erlenmeyer flask system for largescale cultivation of insect cells is described and compared to a commercial spinner system. On the basis of maximum cell density, average population doubling time and overproduction of recombinant protein, a better result was obtained with a simpler and less expensive biorector consisting of Erlenmeyer flasks and an ordinary shaker waterbath. Routinely, about 90 mg of pure poly(ADP-ribose) polymerase catalytic domain was obtained for a total of 3 x 10(9) infected cells in three liters of culture.

Insights into the mechanism of action of benzoyl peroxide as a tumor promoter.

A comparison of the mechanism of action of benzoyl peroxide, a tumor promoter was studied in three different cell lines i.e. NIH 3T3, HDCS and A431. Benzoyl peroxide was found to mediate its effect by inducing poly ADP-ribosylation in all the three cell types studied but to different extents, with histone H1 serving as a common acceptor for poly ADP-ribose. It also stimulated the activities of the antioxidant enzymes CuZn superoxide dismutase and catalase in NIH 3T3 and HDCS cells, but not in A431. Alterations in the expression of c-jun and c-fos were observed in NIH 3T3 and A431 cells. Benzoyl Peroxide appeared to mediate its effect via genetic and epigenetic mechanisms.