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Jiang JL, Zhou YY, Zhong WW, Luo LY, Liu SY, Xie XY, Mu MY, Jiang ZG, Xue Y, Zhang J, He YH. Uridine diphosphate glucuronosyltransferase 1A1 prevents the progression of liver injury. World J Gastroenterol 2024; 30:1189-1212. [PMID: 38577195 PMCID: PMC10989491 DOI: 10.3748/wjg.v30.i9.1189] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/28/2023] [Revised: 01/02/2024] [Accepted: 01/29/2024] [Indexed: 03/06/2024] Open
Abstract
BACKGROUND Uridine diphosphate glucuronosyltransferase 1A1 (UGT1A1) plays a crucial role in metabolizing and detoxifying endogenous and exogenous substances. However, its contribution to the progression of liver damage remains unclear. AIM To determine the role and mechanism of UGT1A1 in liver damage progression. METHODS We investigated the relationship between UGT1A1 expression and liver injury through clinical research. Additionally, the impact and mechanism of UGT1A1 on the progression of liver injury was analyzed through a mouse model study. RESULTS Patients with UGT1A1 gene mutations showed varying degrees of liver damage, while patients with acute-on-chronic liver failure (ACLF) exhibited relatively reduced levels of UGT1A1 protein in the liver as compared to patients with chronic hepatitis. This suggests that low UGT1A1 levels may be associated with the progression of liver damage. In mouse models of liver injury induced by carbon tetrachloride (CCl4) and concanavalin A (ConA), the hepatic levels of UGT1A1 protein were found to be increased. In mice with lipopolysaccharide or liver steatosis-mediated liver-injury progression, the hepatic protein levels of UGT1A1 were decreased, which is consistent with the observations in patients with ACLF. UGT1A1 knockout exacerbated CCl4- and ConA-induced liver injury, hepatocyte apoptosis and necroptosis in mice, intensified hepatocyte endoplasmic reticulum (ER) stress and oxidative stress, and disrupted lipid metabolism. CONCLUSION UGT1A1 is upregulated as a compensatory response during liver injury, and interference with this upregulation process may worsen liver injury. UGT1A1 reduces ER stress, oxidative stress, and lipid metabolism disorder, thereby mitigating hepatocyte apoptosis and necroptosis.
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Affiliation(s)
- Jin-Lian Jiang
- Department of Infectious Diseases, Affiliated Hospital of Zunyi Medical University, Zunyi 563000, Guizhou Province, China
| | - Yi-Yang Zhou
- Department of Infectious Diseases, Affiliated Hospital of Zunyi Medical University, Zunyi 563000, Guizhou Province, China
| | - Wei-Wei Zhong
- Department of Infectious Diseases, Jingmen Central Hospital, Jingmen 448000, Hubei Province, China
| | - Lin-Yan Luo
- Department of Respiratory Medicine, Anshun People’s Hospital, Anshun 561099, Guizhou Province, China
| | - Si-Ying Liu
- Department of Infectious Diseases, Affiliated Hospital of Zunyi Medical University, Zunyi 563000, Guizhou Province, China
| | - Xiao-Yu Xie
- Department of General Practice, Affiliated Hospital of Zunyi Medical University, Zunyi 563000, Guizhou Province, China
| | - Mao-Yuan Mu
- Department of Intervention Radiology, Affiliated Hospital of Zunyi Medical University, Zunyi 563000, Guizhou Province, China
| | - Zhi-Gang Jiang
- School of Public Health, Zunyi Medical University, Zunyi 563099, Guizhou Province, China
| | - Yuan Xue
- Department of Liver Diseases, Third People’s Hospital of Changzhou, Changzhou 213000, Jiangsu Province, China
| | - Jian Zhang
- Department of Digestion, Dafang County People’s Hospital, Bijie 551600, Guizhou Province, China
| | - Yi-Huai He
- Department of Infectious Diseases, Affiliated Hospital of Zunyi Medical University, Zunyi 563000, Guizhou Province, China
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Wang Z, Xu J, Cheng X, Zhang L, Wang D, Pan J. Hyperbilirubinemia after surgical repair for acute type a aortic dissection: A propensity score-matched analysis. Front Physiol 2022; 13:1009007. [PMID: 36299262 PMCID: PMC9589278 DOI: 10.3389/fphys.2022.1009007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Accepted: 09/22/2022] [Indexed: 11/29/2022] Open
Abstract
Background: Inflammation and oxidative stress are known to participate in the pathogenesis of hyperbilirubinemia. It has been known that acute type A aortic dissection (ATAAD) surgical repair often associates with complications which might affect the long-term prognosis. However, the clinical significance of postoperative hyperbilirubinemia (PH) has not been evaluated. Here in this study, we examined the incidence, risk factors, and prognosis of PH after ATAAD surgery. Methods: This retrospective study enrolled a total of 970 patients who received ATAAD surgical repair from January 2014 to December 2019. PH was defined as serum total bilirubin >3.0 mg/dl within the first week after the surgery. Propensity score matching was used to reduce selection bias and eliminate potential confounding factors. Kaplan–Meier survival and Cox proportional hazards regression analyses were conducted to explore the association between PH and postoperative long-term survival. Results: Development of PH (183 patients) was associated with a higher 30-Day mortality (20.8% vs. 9.0%, p < 0.001). Advanced age [odds ratio (OR) 1.538, p = 0.006], higher baseline total bilirubin level (OR 1.735, p = 0.026), preoperative pericardial tamponade (OR 3.192, p = 0.024), prolonged cardiopulmonary bypass (CPB) duration (OR 2.008, p = 0.005), and elevated postoperative central venous pressure (CVP) level (OR 2.183, p < 0.001) were associated with PH. The Kaplan-Meier analysis showed patients who developed PH were associated with poor long-term survival (p = 0.044). Cox analysis showed that the presence of PH (hazard ratio 2.006, p = 0.003) was an independent risk factor for increased mortality. Conclusion: PH is a common complication in patients undergoing ATAAD surgical repair that associates with worse short- and long-term prognosis. Our data indicated that age, preoperative total bilirubin level, pericardial tamponade, CPB duration, and postoperative CVP level were risk factors for the development of PH.
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Affiliation(s)
- Zhigang Wang
- Department of Cardio-Thoracic Surgery, Affiliated Drum Tower Hospital, Medical School of Nanjing University, Nanjing, China
| | - Jingfang Xu
- Department of Nephrology, Nanjing Drum Tower Hospital Clinical College of Nanjing University of Chinese Medicine, Nanjing, China
| | - Xiaofeng Cheng
- Department of Cardio-Thoracic Surgery, Nanjing Drum Tower Hospital Clinical College of Traditional Chinese and Western Medicine, Nanjing University of Chinese Medicine, Nanjing, China
| | - Lifang Zhang
- Department of Psychiatry, The First Affiliated Hospital, Zhengzhou University, Zhengzhou, China
| | - Dongjin Wang
- Department of Cardio-Thoracic Surgery, Affiliated Drum Tower Hospital, Medical School of Nanjing University, Nanjing, China
- Department of Cardio-Thoracic Surgery, Nanjing Drum Tower Hospital Clinical College of Traditional Chinese and Western Medicine, Nanjing University of Chinese Medicine, Nanjing, China
- *Correspondence: Jun Pan, ; Dongjin Wang,
| | - Jun Pan
- Department of Cardio-Thoracic Surgery, Affiliated Drum Tower Hospital, Medical School of Nanjing University, Nanjing, China
- *Correspondence: Jun Pan, ; Dongjin Wang,
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Shahrokhi SZ, Tehrani FSK, Salami S. Molecular mechanisms of bilirubin induced G1 cell cycle arrest and apoptosis in human breast cancer cell lines: involvement of the intrinsic pathway. Mol Biol Rep 2022; 49:10421-10429. [DOI: 10.1007/s11033-022-07757-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Revised: 06/27/2022] [Accepted: 06/29/2022] [Indexed: 11/24/2022]
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Abstract
PURPOSE OF REVIEW Hyperbilirubinemia is commonly seen in neonates. Though hyperbilirubinemia is typically asymptomatic, severe elevation of bilirubin levels can lead to acute bilirubin encephalopathy and progress to kernicterus spectrum disorder, a chronic condition characterized by hearing loss, extrapyramidal dysfunction, ophthalmoplegia, and enamel hypoplasia. Epidemiological data show that the implementation of universal pre-discharge bilirubin screening programs has reduced the rates of hyperbilirubinemia-associated complications. However, acute bilirubin encephalopathy and kernicterus spectrum disorder are still particularly common in low- and middle-income countries. RECENT FINDINGS The understanding of the genetic and biochemical processes that increase the susceptibility of defined anatomical areas of the central nervous system to the deleterious effects of bilirubin may facilitate the development of effective treatments for acute bilirubin encephalopathy and kernicterus spectrum disorder. Scoring systems are available for the diagnosis and severity grading of these conditions. The treatment of hyperbilirubinemia in newborns relies on the use of phototherapy and exchange transfusion. However, novel therapeutic options including deep brain stimulation, brain-computer interface, and stem cell transplantation may alleviate the heavy disease burden associated with kernicterus spectrum disorder. Despite improved screening and treatment options, the prevalence of acute bilirubin encephalopathy and kernicterus spectrum disorder remains elevated in low- and middle-income countries. The continued presence and associated long-term disability of these conditions warrant further research to improve their prevention and management.
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Affiliation(s)
- Shuo Qian
- Department of Neurology and Rehabilitation, University of Illinois at Chicago College of Medicine, 912 S Wood St, Chicago, IL, 60612, USA.
| | - Prateek Kumar
- Department of Neurology and Rehabilitation, University of Illinois at Chicago College of Medicine, 912 S Wood St, Chicago, IL, 60612, USA
| | - Fernando D Testai
- Department of Neurology and Rehabilitation, University of Illinois at Chicago College of Medicine, 912 S Wood St, Chicago, IL, 60612, USA
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Liu D, Yu Q, Li Z, Zhang L, Hu M, Wang C, Liu Z. UGT1A1 dysfunction increases liver burden and aggravates hepatocyte damage caused by long-term bilirubin metabolism disorder. Biochem Pharmacol 2021; 190:114592. [PMID: 33961837 DOI: 10.1016/j.bcp.2021.114592] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Revised: 04/29/2021] [Accepted: 04/30/2021] [Indexed: 12/15/2022]
Abstract
UGT1A1 is the only enzyme that can metabolize bilirubin, and its encoding gene is frequently mutated. UGT1A1*6 (G71R) is a common mutant in Asia which leads to the decrease of UGT1A1 activity and abnormal bilirubin metabolism. However, it is not clear whether low UGT1A1 activity-induced bilirubin metabolism disorder increases hepatocyte fragility. ugt1a+/- mice were used to simulate the UGT1A1*6 (G71R) population. Under the same CCl4 induction condition, ugt1a+/- mice showed severer liver damage and fibrosis, indicating that ugt1a1 dysfunction increased liver burden and aggravated hepatocyte damage. In the animal experiment with a continuous intraperitoneal injection of bilirubin, the ugt1a+/- mice livers had more serious unconjugated bilirubin accumulation. The accumulated bilirubin leads to hyperphosphorylation of IκB-α, Ikk-β, and p65 and a significant increase of inflammatory factor. The α-SMA and Collagen I proteins markedly up-regulated in the ugt1a+/- mice livers. Immunofluorescence and confocal microscopy showed that hepatic stellate cells and Kupffer cells were activated in ugt1a+/- mice. Comprehensive results show that there was a crosstalk relationship between low UGT1A1 activity-bilirubin-liver damage. Furthermore, cell experiments confirmed that unconjugated bilirubin activated the NF-κB pathway and induced DNA damage in hepatocytes, leading to the significant increase of inflammatory factors. UGT1A1 knockdown in hepatocytes aggravated the toxicity of unconjugated bilirubin. Conversely, overexpression of UGT1A1 had a protective effect on hepatocytes. Finally, Schisandrin B, an active ingredient with hepatoprotective effects, extracted from a traditional Chinese medicinal herb, which could protect the liver from bilirubin metabolism disorders caused by ugt1a1 deficiency by downregulating p65 phosphorylation, inhibiting Kupffer cells, reducing inflammation levels. Our data clarified the mechanism of liver vulnerability caused by cross-talk between low UGT1A1 activity bilirubin, and provided a reference for individualized prevention of liver fragility in Gilbert's syndrome.
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Affiliation(s)
- Dan Liu
- Guangdong Key Laboratory for Translational Cancer Research of Chinese Medicine, Joint Laboratory for Translational Cancer Research of Chinese Medicine of the Ministry of Education of the People's Republic of China, International Institute for Translational Chinese Medicine, Guangzhou University of Chinese Medicine, Guangzhou, Guangdong 510006, China; Affiliated Hospital of Integrated Traditional Chinese and Western Medicine, Nanjing University of Chinese Medicine, Nanjing, Jiangsu 210028, China
| | - Qi Yu
- Guangdong Key Laboratory for Translational Cancer Research of Chinese Medicine, Joint Laboratory for Translational Cancer Research of Chinese Medicine of the Ministry of Education of the People's Republic of China, International Institute for Translational Chinese Medicine, Guangzhou University of Chinese Medicine, Guangzhou, Guangdong 510006, China
| | - Zibo Li
- Guangdong Key Laboratory for Translational Cancer Research of Chinese Medicine, Joint Laboratory for Translational Cancer Research of Chinese Medicine of the Ministry of Education of the People's Republic of China, International Institute for Translational Chinese Medicine, Guangzhou University of Chinese Medicine, Guangzhou, Guangdong 510006, China
| | - Lin Zhang
- Guangdong Key Laboratory for Translational Cancer Research of Chinese Medicine, Joint Laboratory for Translational Cancer Research of Chinese Medicine of the Ministry of Education of the People's Republic of China, International Institute for Translational Chinese Medicine, Guangzhou University of Chinese Medicine, Guangzhou, Guangdong 510006, China
| | - Ming Hu
- Guangdong Key Laboratory for Translational Cancer Research of Chinese Medicine, Joint Laboratory for Translational Cancer Research of Chinese Medicine of the Ministry of Education of the People's Republic of China, International Institute for Translational Chinese Medicine, Guangzhou University of Chinese Medicine, Guangzhou, Guangdong 510006, China; Department of Pharmacological and Pharmaceutical Sciences, College of Pharmacy, University of Houston, Houston, TX 77030, United States
| | - Caiyan Wang
- Guangdong Key Laboratory for Translational Cancer Research of Chinese Medicine, Joint Laboratory for Translational Cancer Research of Chinese Medicine of the Ministry of Education of the People's Republic of China, International Institute for Translational Chinese Medicine, Guangzhou University of Chinese Medicine, Guangzhou, Guangdong 510006, China.
| | - Zhongqiu Liu
- Guangdong Key Laboratory for Translational Cancer Research of Chinese Medicine, Joint Laboratory for Translational Cancer Research of Chinese Medicine of the Ministry of Education of the People's Republic of China, International Institute for Translational Chinese Medicine, Guangzhou University of Chinese Medicine, Guangzhou, Guangdong 510006, China.
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6
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Hansen TWR, Wong RJ, Stevenson DK. Molecular Physiology and Pathophysiology of Bilirubin Handling by the Blood, Liver, Intestine, and Brain in the Newborn. Physiol Rev 2020; 100:1291-1346. [PMID: 32401177 DOI: 10.1152/physrev.00004.2019] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Bilirubin is the end product of heme catabolism formed during a process that involves oxidation-reduction reactions and conserves iron body stores. Unconjugated hyperbilirubinemia is common in newborn infants, but rare later in life. The basic physiology of bilirubin metabolism, such as production, transport, and excretion, has been well described. However, in the neonate, numerous variables related to nutrition, ethnicity, and genetic variants at several metabolic steps may be superimposed on the normal physiological hyperbilirubinemia that occurs in the first week of life and results in bilirubin levels that may be toxic to the brain. Bilirubin exists in several isomeric forms that differ in their polarities and is considered a physiologically important antioxidant. Here we review the chemistry of the bilirubin molecule and its metabolism in the body with a particular focus on the processes that impact the newborn infant, and how differences relative to older children and adults contribute to the risk of developing both acute and long-term neurological sequelae in the newborn infant. The final section deals with the interplay between the brain and bilirubin and its entry, clearance, and accumulation. We conclude with a discussion of the current state of knowledge regarding the mechanism(s) of bilirubin neurotoxicity.
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Affiliation(s)
- Thor W R Hansen
- Division of Paediatric and Adolescent Medicine, Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Oslo, Norway; and Department of Pediatrics, Stanford University School of Medicine, Stanford, California
| | - Ronald J Wong
- Division of Paediatric and Adolescent Medicine, Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Oslo, Norway; and Department of Pediatrics, Stanford University School of Medicine, Stanford, California
| | - David K Stevenson
- Division of Paediatric and Adolescent Medicine, Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Oslo, Norway; and Department of Pediatrics, Stanford University School of Medicine, Stanford, California
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7
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Hayashida M, Hashioka S, Hayashida K, Miura S, Tsuchie K, Araki T, Izuhara M, Kanayama M, Otsuki K, Nagahama M, Jaya MA, Arauchi R, Wake R, Oh-Nishi A, Horiguchi J, Miyaoka T, Inagaki M, Morita E. Low Serum Levels of Fibroblast Growth Factor 2 in Gunn Rats: A Hyperbilirubinemia Animal Model of Schizophrenic Symptoms. CNS & NEUROLOGICAL DISORDERS-DRUG TARGETS 2020; 19:503-508. [PMID: 32729434 DOI: 10.2174/1871527319999200729153907] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Revised: 06/06/2020] [Accepted: 06/07/2020] [Indexed: 11/22/2022]
Abstract
BACKGROUND Fibroblast Growth Factor (FGF) 2 (also referred to as basic FGF) is a multifunctional growth factor that plays a pivotal role in the pro-survival, pro-migration and prodifferentiation of neurons. METHOD Because alterations in FGF2 levels are suggested to contribute to the pathogenesis of schizophrenia, we investigated serum levels of FGF2 in the Gunn rat, a hyperbilirubinemia animal model of schizophrenic symptoms. RESULTS The enzyme-linked immunosorbent assay showed that the serum levels of FGF2 in Gunn rats were 5.09 ± 0.236 pg/mL, while those in the normal strain Wistar rats, serum levels were 11.90 ± 2.142 pg/mL. The serum FGF2 levels in Gunn rats were significantly lower than those in Wistar rats. We also measured serum levels of Unconjugated Bilirubin (UCB) and found a significant negative correlation between UCB and FGF2 in terms of serum levels in all the rats studied. CONCLUSION Since it is known that FGF2 regulates dopaminergic neurons and have antineuroinflammatory effects, our finding suggests that low FGF2 levels may contribute to the pathogenesis of schizophrenia, in which imbalanced dopamin-ergic signaling and neuroinflammation are supposed to play certain roles.
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Affiliation(s)
- Maiko Hayashida
- Department of Psychiatry, Faculty of Medicine, Shimane University, Matsue, Japan
| | - Sadayuki Hashioka
- Department of Psychiatry, Faculty of Medicine, Shimane University, Matsue, Japan
| | - Kenji Hayashida
- Division of Plastic Surgery, Faculty of Medicine, Shimane University, Matsue, Japan
| | - Shoko Miura
- Department of Psychiatry, Faculty of Medicine, Shimane University, Matsue, Japan
| | - Keiko Tsuchie
- Department of Psychiatry, Faculty of Medicine, Shimane University, Matsue, Japan
| | - Tomoko Araki
- Department of Psychiatry, Faculty of Medicine, Shimane University, Matsue, Japan
| | - Muneto Izuhara
- Department of Psychiatry, Faculty of Medicine, Shimane University, Matsue, Japan
| | - Misako Kanayama
- Department of Psychiatry, Faculty of Medicine, Shimane University, Matsue, Japan
| | - Koji Otsuki
- Department of Psychiatry, Faculty of Medicine, Shimane University, Matsue, Japan
| | - Michiharu Nagahama
- Department of Psychiatry, Faculty of Medicine, Shimane University, Matsue, Japan
| | - Muhammad Alim Jaya
- Department of Psychiatry, Faculty of Medicine, Shimane University, Matsue, Japan
| | - Ryosuke Arauchi
- Department of Psychiatry, Faculty of Medicine, Shimane University, Matsue, Japan
| | - Rei Wake
- Department of Psychiatry, Faculty of Medicine, Shimane University, Matsue, Japan
| | - Arata Oh-Nishi
- Department of Immuno-Neuropsychiatry, Faculty of Medicine, Shimane University, Matsue, Japan
| | - Jun Horiguchi
- Department of Immuno-Neuropsychiatry, Faculty of Medicine, Shimane University, Matsue, Japan
| | - Tsuyoshi Miyaoka
- Department of Psychiatry, Faculty of Medicine, Shimane University, Matsue, Japan
| | - Masatoshi Inagaki
- Department of Psychiatry, Faculty of Medicine, Shimane University, Matsue, Japan
| | - Eishin Morita
- Department of Dermatology, Faculty of Medicine, Shimane University, Matsue, Japan
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8
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Bilirubin disrupts calcium homeostasis in neonatal hippocampal neurons: a new pathway of neurotoxicity. Arch Toxicol 2020; 94:845-855. [DOI: 10.1007/s00204-020-02659-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Accepted: 02/03/2020] [Indexed: 12/22/2022]
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9
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Canesin G, Hejazi SM, Swanson KD, Wegiel B. Heme-Derived Metabolic Signals Dictate Immune Responses. Front Immunol 2020; 11:66. [PMID: 32082323 PMCID: PMC7005208 DOI: 10.3389/fimmu.2020.00066] [Citation(s) in RCA: 51] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Accepted: 01/10/2020] [Indexed: 12/21/2022] Open
Abstract
Heme is one of the most abundant molecules in the body acting as the functional core of hemoglobin/myoglobin involved in the O2/CO2 carrying in the blood and tissues, redox enzymes and cytochromes in mitochondria. However, free heme is toxic and therefore its removal is a significant priority for the host. Heme is a well-established danger-associated molecular pattern (DAMP), which binds to toll-like receptor 4 (TLR4) to induce immune responses. Heme-derived metabolites including the bile pigments, biliverdin (BV) and bilirubin (BR), were first identified as toxic drivers of neonatal jaundice in 1800 but have only recently been appreciated as endogenous drivers of multiple signaling pathways involved in protection from oxidative stress and regulators of immune responses. The tissue concentration of heme, BV and BR is tightly controlled. Heme oxygenase-1 (HO-1, encoded by HMOX1) produces BV by heme degradation, while biliverdin reductase-A (BLVR-A) generates BR by the subsequent conversion of BV. BLVR-A is a fascinating protein that possesses a classical protein kinase domain, which is activated in response to BV binding to its enzymatic site and initiates the downstream mitogen-activated protein kinases (MAPK) and phosphatidylinositol 3-kinase (PI3K) pathways. This links BLVR-A activity to cell growth and survival pathways. BLVR-A also contains a bZip DNA binding domain and a nuclear export sequence (NES) and acts as a transcription factor to regulate the expression of immune modulatory genes. Here we will discuss the role of heme-related immune response and the potential for targeting the heme system for therapies directed toward hepatitis and cancer.
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Affiliation(s)
- Giacomo Canesin
- Department of Surgery, Cancer Research Institute and Transplant Institute, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, United States
| | - Seyed M. Hejazi
- Department of Surgery, Cancer Research Institute and Transplant Institute, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, United States
| | - Kenneth D. Swanson
- Brain Tumor Center and Neuro-Oncology Unit, Beth Israel Deaconess Medical Center, Boston, MA, United States
| | - Barbara Wegiel
- Department of Surgery, Cancer Research Institute and Transplant Institute, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, United States
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Experimental models assessing bilirubin neurotoxicity. Pediatr Res 2020; 87:17-25. [PMID: 31493769 DOI: 10.1038/s41390-019-0570-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/17/2019] [Revised: 07/29/2019] [Accepted: 08/16/2019] [Indexed: 02/08/2023]
Abstract
The molecular and cellular events leading to bilirubin-induced neurotoxicity, the mechanisms regulating liver and intestine expression in neonates, and alternative pathways of bilirubin catabolism remain incompletely defined. To answer these questions, researchers have developed a number of model systems to closely recapitulate the main characteristics of the disease, ranging from tissue cultures to engineered mouse models. In the present review we describe in vitro, ex vivo, and in vivo models developed to study bilirubin metabolism and neurotoxicity, with a special focus on the use of engineered animal models. In addition, we discussed the most recent studies related to potential therapeutic approaches to treat neonatal hyperbilirubinemia, ranging from anti-inflammatory drugs, activation of nuclear receptor pathways, blockade of bilirubin catabolism, and stimulation of alternative bilirubin-disposal pathways.
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11
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Genetic Deletion or Pharmacological Inhibition of Soluble Epoxide Hydrolase Ameliorates Cardiac Ischemia/Reperfusion Injury by Attenuating NLRP3 Inflammasome Activation. Int J Mol Sci 2019; 20:ijms20143502. [PMID: 31319469 PMCID: PMC6678157 DOI: 10.3390/ijms20143502] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2019] [Revised: 07/12/2019] [Accepted: 07/16/2019] [Indexed: 02/06/2023] Open
Abstract
Activation of the nucleotide-binding oligomerization domain-like receptor (NLR) family pyrin domain containing 3 (NLRP3) inflammasome cascade has a role in the pathogenesis of ischemia/reperfusion (IR) injury. There is growing evidence indicating cytochrome p450 (CYP450)-derived metabolites of n-3 and n-6 polyunsaturated fatty acids (PUFAs) possess both adverse and protective effects in the heart. CYP-derived epoxy metabolites are rapidly hydrolyzed by the soluble epoxide hydrolase (sEH). The current study hypothesized that the cardioprotective effects of inhibiting sEH involves limiting activation of the NLRP3 inflammasome. Isolated hearts from young wild-type (WT) and sEH null mice were perfused in the Langendorff mode with either vehicle or the specific sEH inhibitor t-AUCB. Improved post-ischemic functional recovery and better mitochondrial respiration were observed in both sEH null hearts or WT hearts perfused with t-AUCB. Inhibition of sEH markedly attenuated the activation of the NLRP3 inflammasome complex and limited the mitochondrial localization of the fission protein dynamin-related protein-1 (Drp-1) triggered by IR injury. Cardioprotective effects stemming from the inhibition of sEH included preserved activities of both cytosolic thioredoxin (Trx)-1 and mitochondrial Trx-2 antioxidant enzymes. Together, these data demonstrate that inhibiting sEH imparts cardioprotection against IR injury via maintaining post-ischemic mitochondrial function and attenuating a detrimental innate inflammatory response.
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Hayashida M, Miyaoka T, Tsuchie K, Araki T, Izuhara M, Miura S, Kanayama M, Ohtsuki K, Nagahama M, Azis IA, Abdullah RA, Jaya MA, Arauchi R, Hashioka S, Wake R, Tsumori T, Horiguchi J, Oh-Nishi A, Inagaki M. Parvalbumin-positive GABAergic interneurons deficit in the hippocampus in Gunn rats: A possible hyperbilirubinemia-induced animal model of schizophrenia. Heliyon 2019; 5:e02037. [PMID: 31321330 PMCID: PMC6612903 DOI: 10.1016/j.heliyon.2019.e02037] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Revised: 05/18/2019] [Accepted: 07/01/2019] [Indexed: 11/25/2022] Open
Abstract
A reduction of GABAergic markers in postmortem tissue is consistently found in schizophrenia. Importantly, these alterations in GABAergic neurons are not global, which means they are more prevalent among distinct subclasses of interneurons, including those that express the calcium binding protein parvalbumin. A decreased expression of parvalbumin in the hippocampus is a consistent observation not only in postmortem human schizophrenia patients, but also in a diverse number of rodent models of the disease. Meanwhile, previously we reported that the congenital hyperbilirubinemia model rats (Gunn rats), which is a mutant of the Wistar strain, showed behavioral abnormalities, for instance, hyperlocomotor activity, deficits of prepulse inhibition, inappropriate social interaction, impaired recognition memory similar with several rodent models of schizophrenia. Several animal studies linked the importance of palvalbumin in relation to abnormal hippocampal activity and schizophrenia-like behavior. Here, we show that parvalbumin positive cell density was significantly lower in the CA1, CA3 and the total hippocampus of Gunn rats (congenital hyperbilirubinemia model rats) compared to Wistar control rats. The correlations between serum UCB levels and loss of PV expression in the hippocampus were also detected. The decreases in the PV-expression in the hippocampus might suggest an association of the behavioral abnormalities as schizophrenia-like behaviors of Gunn rats, compared to the Wistar control rats.
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Affiliation(s)
- Maiko Hayashida
- Department of Psychiatry, Faculty of Medicine, Shimane University, Japan
| | - Tsuyoshi Miyaoka
- Department of Psychiatry, Faculty of Medicine, Shimane University, Japan
| | - Keiko Tsuchie
- Department of Psychiatry, Faculty of Medicine, Shimane University, Japan
| | - Tomoko Araki
- Department of Psychiatry, Faculty of Medicine, Shimane University, Japan
| | - Muneto Izuhara
- Department of Psychiatry, Faculty of Medicine, Shimane University, Japan
| | - Shoko Miura
- Department of Psychiatry, Faculty of Medicine, Shimane University, Japan
| | - Misako Kanayama
- Department of Psychiatry, Faculty of Medicine, Shimane University, Japan
| | - Koji Ohtsuki
- Department of Psychiatry, Faculty of Medicine, Shimane University, Japan
| | - Michiharu Nagahama
- Department of Psychiatry, Faculty of Medicine, Shimane University, Japan
| | | | | | - Muhammad Alim Jaya
- Department of Psychiatry, Faculty of Medicine, Shimane University, Japan
| | - Ryosuke Arauchi
- Department of Psychiatry, Faculty of Medicine, Shimane University, Japan
| | - Sadayuki Hashioka
- Department of Psychiatry, Faculty of Medicine, Shimane University, Japan
| | - Rei Wake
- Department of Psychiatry, Faculty of Medicine, Shimane University, Japan
| | - Toshiko Tsumori
- Department of Nursing, Faculty of Health and Welfare, Prefectural University of Hiroshima, Japan
| | - Jun Horiguchi
- Division of Immune-Neuropsychiatry, Faculty of Medicine, Shimane University, Japan
| | - Arata Oh-Nishi
- Division of Immune-Neuropsychiatry, Faculty of Medicine, Shimane University, Japan
- RESVO Inc., Japan
| | - Masatoshi Inagaki
- Department of Psychiatry, Faculty of Medicine, Shimane University, Japan
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13
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Darwesh AM, Jamieson KL, Wang C, Samokhvalov V, Seubert JM. Cardioprotective effects of CYP-derived epoxy metabolites of docosahexaenoic acid involve limiting NLRP3 inflammasome activation. Can J Physiol Pharmacol 2019; 97:544-556. [DOI: 10.1139/cjpp-2018-0480] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Impaired mitochondrial function and activation of NLRP3 inflammasome cascade has a significant role in the pathogenesis of myocardial ischemia–reperfusion (IR) injury. The current study investigated whether eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), or their corresponding CYP epoxygenase metabolites 17,18-epoxyeicosatetraenoic acid (17,18-EEQ) and 19,20-epoxydocosapentaenoic acid (19,20-EDP) protect against IR injury. Isolated mouse hearts were perfused in the Langendorff mode with vehicle, DHA, 19,20-EDP, EPA, or 17,18-EEQ and subjected to 30 min of ischemia and followed by 40 min of reperfusion. In contrast with EPA and 17,18-EEQ, DHA and 19,20-EDP exerted cardioprotection, as shown by a significant improvement in postischemic functional recovery associated with significant attenuation of NLRP3 inflammasome complex activation and preserved mitochondrial function. Hearts perfused with DHA or 19,20-EDP displayed a marked reduction in localization of mitochondrial Drp-1 and Mfn-2 as well as maintained Opa-1 levels. DHA and 19,20-EDP preserved the activities of both the cytosolic Trx-1 and mitochondrial Trx-2. DHA cardioprotective effect was attenuated by the CYP epoxygenase inhibitor N-(methysulfonyl)-2-(2-propynyloxy)-benzenehexanamide. In conclusion, our data indicate a differential cardioprotective response between DHA, EPA, and their active metabolites toward IR injury. Interestingly, 19,20-EDP provided the best protection against IR injury via maintaining mitochondrial function and thereby reducing the detrimental NLRP3 inflammasome responses.
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Affiliation(s)
- Ahmed M. Darwesh
- Faculty of Pharmacy and Pharmaceutical Sciences, University of Alberta, Edmonton, AB T6G 2R3, Canada
| | - K. Lockhart Jamieson
- Faculty of Pharmacy and Pharmaceutical Sciences, University of Alberta, Edmonton, AB T6G 2R3, Canada
| | - Chuying Wang
- Faculty of Pharmacy and Pharmaceutical Sciences, University of Alberta, Edmonton, AB T6G 2R3, Canada
- School of Pharmaceutical Sciences, Changchun University of Chinese Medicine, Changchun, China
| | - Victor Samokhvalov
- Faculty of Pharmacy and Pharmaceutical Sciences, University of Alberta, Edmonton, AB T6G 2R3, Canada
| | - John M. Seubert
- Faculty of Pharmacy and Pharmaceutical Sciences, University of Alberta, Edmonton, AB T6G 2R3, Canada
- Department of Pharmacology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB T6G 2R3, Canada
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Bilirubin-Induced Oxidative Stress Leads to DNA Damage in the Cerebellum of Hyperbilirubinemic Neonatal Mice and Activates DNA Double-Strand Break Repair Pathways in Human Cells. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2018; 2018:1801243. [PMID: 30598724 PMCID: PMC6287157 DOI: 10.1155/2018/1801243] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Revised: 09/19/2018] [Accepted: 10/02/2018] [Indexed: 12/27/2022]
Abstract
Unconjugated bilirubin is considered a potent antioxidant when present at moderate levels. However, at high concentrations, it produces severe neurological damage and death associated with kernicterus due to oxidative stress and other mechanisms. While it is widely recognized that oxidative stress by different toxic insults results in severe damage to cellular macromolecules, especially to DNA, no data are available either on DNA damage in the brain triggered by hyperbilirubinemia during the neonatal period or on the activation of DNA repair mechanisms. Here, using a mouse model of neonatal hyperbilirubinemia, we demonstrated that DNA damage occurs in vivo in the cerebellum, the brain region most affected by bilirubin toxicity. We studied the mechanisms associated with potential toxic action of bilirubin on DNA in in vitro models, which showed significant increases in DNA damage when neuronal and nonneuronal cells were treated with 140 nM of free bilirubin (Bf), as determined by γH2AX Western blot and immunofluorescence analyses. Cotreatment of cells with N-acetyl-cysteine, a potent oxidative-stress inhibitor, prevented DNA damage by bilirubin, supporting the concept that DNA damage was caused by bilirubin-induced oxidative stress. Bilirubin treatment also activated the main DNA repair pathways through homologous recombination (HR) and nonhomologous end joining (NHEJ), which may be adaptive responses to repair bilirubin-induced DNA damage. Since DNA damage may be another important factor contributing to neuronal death and bilirubin encephalopathy, these results contribute to the understanding of the mechanisms associated with bilirubin toxicity and may be of relevance in neonates affected with severe hyperbilirubinemia.
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Abstract
BACKGROUND Crigler-Najjar syndrome type I (CNI) arises from biallelic variants of UGT1A1 that abrogate uridine diphosphate glucuronosyltransferase (UGT1A1) activity resulting in unconjugated hyperbilirubinemia. Historically, liver parenchyma in CNI was considered structurally and histologically normal. Recent review of CNI liver explants revealed fibrosis. Our aim was to investigate the association between hepatic histology and disease phenotype in CNI. METHODS We extracted data from the medical record at the time of liver transplant from 22 patients with CNI at the Children's Hospital of Pittsburgh, and reviewed explant histology. Continuous data were normally distributed, are presented as mean (±1 SD), and analyzed using two-tailed Student t-test. Categorical data were analyzed using the Chi-square test. RESULTS Both alanine transaminase (ALT; mean 87.4 IU/L) and aspartate transaminase (AST; mean 54.6 IU/L) were elevated. Nine (41%) of 22 explants had significant fibrosis. Pericentral (n = 5), periportal (n = 2), and mixed (n = 2) patterns of fibrosis occurred. A significant difference in mean age of subjects with fibrotic versus non-fibrotic livers (16.1 years vs 10.5 years; P = 0.02) was seen. There were no indices of synthetic liver dysfunction or portal hypertension. Neither a history of gallstone disease nor excess weight appeared to contribute to the development of fibrosis. CONCLUSIONS For the first time, we report a 41% prevalence of clinically silent, yet histologically significant fibrosis among subjects with Crigler-Najjar type 1. Risk for fibrosis appears to accrue with time, indicating that earlier intervention may be prudent whenever considering alternative treatments such as hepatocyte transplant, auxiliary liver transplant, or viral gene therapy.
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16
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Cunningham AD, Hwang S, Mochly-Rosen D. Glucose-6-Phosphate Dehydrogenase Deficiency and the Need for a Novel Treatment to Prevent Kernicterus. Clin Perinatol 2016; 43:341-54. [PMID: 27235212 PMCID: PMC8265784 DOI: 10.1016/j.clp.2016.01.010] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Hyperbilirubinemia occurs frequently in newborns, and in severe cases can progress to kernicterus and permanent developmental disorders. Glucose-6-phosphate dehydrogenase (G6PD) deficiency, one of the most common human enzymopathies, is a major risk factor for hyperbilirubinemia and greatly increases the risk of kernicterus even in the developed world. Therefore, a novel treatment for kernicterus is needed, especially for G6PD-deficient newborns. Oxidative stress is a hallmark of bilirubin toxicity in the brain. We propose that the activation of G6PD via a small molecule chaperone is a potential strategy to increase endogenous defense against bilirubin-induced oxidative stress and prevent kernicterus.
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Affiliation(s)
- Anna D Cunningham
- Department of Chemical and Systems Biology, Stanford University, 269 Campus Drive, Stanford, CA 94305, USA
| | - Sunhee Hwang
- Department of Chemical and Systems Biology, Stanford University, 269 Campus Drive, Stanford, CA 94305, USA
| | - Daria Mochly-Rosen
- Department of Chemical and Systems Biology, Stanford University, 269 Campus Drive, Stanford, CA 94305, USA.
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17
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Samokhvalov V, Vriend J, Jamieson KL, Akhnokh MK, Manne R, Falck JR, Seubert JM. PPARγ signaling is required for mediating EETs protective effects in neonatal cardiomyocytes exposed to LPS. Front Pharmacol 2014; 5:242. [PMID: 25426073 PMCID: PMC4227494 DOI: 10.3389/fphar.2014.00242] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2014] [Accepted: 10/23/2014] [Indexed: 12/30/2022] Open
Abstract
Lipopolysaccharide (LPS) is a bacterial wall endotoxin producing many pathophysiological conditions including myocardial inflammation leading to cardiotoxicity. Epoxyeicosatrienoic acids (EETs) are biologically active metabolites of arachidonic acids capable of activating protective cellular pathways in response to stress stimuli. EETs evoke a plethora of pathways limiting impairments of cellular structures, reducing cell death, and promoting anti-inflammatory reactions in various cell types. Considering EETs are capable of producing various biological protective effects, we hypothesized that EETs would protect rat neonatal cardiomyocytes (NCM) against LPS-induced cytotoxicity. In this study, we used a dual-acting, synthetic analog of EETs, UA-8 [13-(3-propylureido)tridec-8-enoic acid], possessing both EET-mimetic and soluble epoxide hydrolase selective inhibitory properties and 14,15-EET as a model of canonical EET molecules. We found that both UA-8 and 14,15-EET significantly improved cell viability and mitochondrial function of cardiomyocytes exposed to LPS. Furthermore, treatment with UA-8 or 14,15-EET resulted in significant attenuation of LPS-triggered pro-inflammatory response, caspase-3 activation and reduction in the total antioxidant capacity in cardiomyocytes. Importantly, EET-mediated effects were significantly reduced by pharmacological inhibition of peroxisome proliferator-activated receptors γ (PPARγ) suggesting that PPARγ signaling was required for EETs exerted protective effects. Data presented in the current study demonstrate that activation of PPARγ signaling plays a crucial role in EET-mediated protection against LPS-cytotoxicity in cardiomyocytes.
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Affiliation(s)
- Victor Samokhvalov
- Faculty of Pharmacy and Pharmaceutical Sciences, University of Alberta Edmonton, AB, Canada
| | - Jelle Vriend
- Faculty of Pharmacy and Pharmaceutical Sciences, University of Alberta Edmonton, AB, Canada ; Department of Chemistry and Pharmaceutical Sciences, Faculty of Sciences, VU University Amsterdam, Netherlands
| | - Kristi L Jamieson
- Faculty of Pharmacy and Pharmaceutical Sciences, University of Alberta Edmonton, AB, Canada
| | - Maria K Akhnokh
- Faculty of Pharmacy and Pharmaceutical Sciences, University of Alberta Edmonton, AB, Canada
| | - Rajkumar Manne
- Department of Biochemistry and Pharmacology, University of Texas Southwestern Medical Center Dallas, TX, USA
| | - John R Falck
- Department of Biochemistry and Pharmacology, University of Texas Southwestern Medical Center Dallas, TX, USA
| | - John M Seubert
- Faculty of Pharmacy and Pharmaceutical Sciences, University of Alberta Edmonton, AB, Canada ; Department of Pharmacology, Faculty of Medicine and Dentistry, University of Alberta Edmonton, AB, Canada
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18
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Bisht K, Tampe J, Shing C, Bakrania B, Winearls J, Fraser J, Wagner KH, Bulmer AC. Endogenous Tetrapyrroles Influence Leukocyte Responses to Lipopolysaccharide in Human Blood: Pre-Clinical Evidence Demonstrating the Anti-Inflammatory Potential of Biliverdin. ACTA ACUST UNITED AC 2014; 5:1000218. [PMID: 25177524 PMCID: PMC4145741 DOI: 10.4172/2155-9899.1000218] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Sepsis is associated with abnormal host immune function in response to pathogen exposure, including endotoxin (lipopolysaccharide; LPS). Cytokines play crucial roles in the induction and resolution of inflammation in sepsis. Therefore, the primary aim of this study was to investigate the effects of endogenous tetrapyrroles, including biliverdin (BV) and unconjugated bilirubin (UCB) on LPS-induced cytokines in human blood. Biliverdin and UCB are by products of haem catabolism and have strong cytoprotective, antioxidant and anti-inflammatory effects. In the present study, whole human blood supplemented with BV and without was incubated in the presence or absence of LPS for 4 and 8 hours. Thereafter, whole blood was analysed for gene and protein expression of cytokines, including IL-1β, IL-6, TNF, IFN-γ, IL-1Ra and IL-8. Biliverdin (50 μM) significantly decreased the LPS-mediated gene expression of IL-1β, IL-6, IFN-γ, IL-1Ra and IL-8 (P<0.05). Furthermore, BV significantly decreased LPS-induced secretion of IL-1β and IL-8 (P<0.05). Serum samples from human subjects and, wild type and hyperbilirubinaemic Gunn rats were also used to assess the relationship between circulating bilirubin and cytokine expression/production. Significant positive correlations between baseline UCB concentrations in human blood and LPS-mediated gene expression of IL-1β (R=0.929), IFN-γ (R=0.809), IL-1Ra (R=0.786) and IL-8 (R=0.857) were observed in blood samples (all P<0.05). These data were supported by increased baseline IL-1β concentrations in hyperbilirubinaemic Gunn rats (P<0.05). Blood samples were also investigated for complement receptor-5 (C5aR) expression. Stimulation of blood with LPS decreased gene expression of C5aR (P<0.05). Treatment of blood with BV alone and in the presence of LPS tended to decrease C5aR expression (P=0.08). These data indicate that supplemented BV inhibits the ex vivo response of human blood to LPS. Surprisingly, however, baseline UCB was associated with heighted inflammatory response to LPS. This is the first study to explore the effects of BV in a preclinical human model of inflammation and suggests that BV could represent an anti-inflammatory target for the prevention of LPS mediated inflammation in vivo.
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Affiliation(s)
- Kavita Bisht
- Heart Foundation Research Centre, Griffith Health Institute, Griffith University, Gold Coast, QLD, Australia
| | - Jens Tampe
- Griffith Enterprise, Griffith University, Nathan, QLD, Australia
| | - Cecilia Shing
- School of Health Sciences, University of Tasmania, Launceston, Tasmania, Australia
| | - Bhavisha Bakrania
- Heart Foundation Research Centre, Griffith Health Institute, Griffith University, Gold Coast, QLD, Australia
| | - James Winearls
- Gold Coast University Hospital Intensive Care Unit and Gold Coast University Hospital Critical Care Research Group, Gold Coast, QLD, Australia
| | - John Fraser
- Critical Care Research Group, The Prince Charles Hospital, University of Queensland, QLD, Australia
| | - Karl-Heinz Wagner
- Emerging Field Oxidative Stress and DNA Stability and Research Platform Active Aging, Department of Nutritional Science, University of Vienna, Vienna, Austria
| | - Andrew C Bulmer
- Heart Foundation Research Centre, Griffith Health Institute, Griffith University, Gold Coast, QLD, Australia ; Gold Coast University Hospital Intensive Care Unit and Gold Coast University Hospital Critical Care Research Group, Gold Coast, QLD, Australia
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19
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Qaisiya M, Coda Zabetta CD, Bellarosa C, Tiribelli C. Bilirubin mediated oxidative stress involves antioxidant response activation via Nrf2 pathway. Cell Signal 2013; 26:512-20. [PMID: 24308969 DOI: 10.1016/j.cellsig.2013.11.029] [Citation(s) in RCA: 104] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2013] [Revised: 11/21/2013] [Accepted: 11/26/2013] [Indexed: 12/22/2022]
Abstract
Unconjugated bilirubin (UCB) is responsible for neonatal jaundice and high level of free bilirubin (Bf) can lead to kernicterus. Previous studies suggest that oxidative stress is a critical component of UCB-induced neurotoxicity. The Nrf2 pathway is a powerful sensor for cellular redox state and is activated directly by oxidative stress and/or indirectly by stress response protein kinases. Activated Nrf2 translocates to nucleus, binds to Antioxidant Response Element (ARE), and enhances the up-regulation of cytoprotective genes that mediate cell survival. The aim of the present study was to investigate the role of Nrf2 pathway in cell response to bilirubin mediated oxidative stress in the neuroblastoma SH-SY5Y cell line. Cells exposed to a toxic concentration of UCB (140 nM Bf) showed an increased intracellular ROS levels and enhanced nuclear accumulation of Nrf2 protein. UCB stimulated transcriptional induction of ARE-GFP reporter gene and induced mRNA expression of multiple antioxidant response genes as: xCT, Gly1, γGCL-m, γGCL-c, HO-1, NQO1, FTH, ME1, and ATF3. Nrf2 siRNA decreased UCB induced mRNA expression of HO1 (75%), NQO1 (54%), and FTH (40%). The Nrf2-related HO-1 induction was reduced to 60% in cells pre-treated with antioxidant (NAC) or specific signaling pathway inhibitors for PKC, P38α and MEK1/2 (80, 40 and 25%, respectively). In conclusion, we demonstrated that SH-SY5Y cells undergo an adaptive response against UCB-mediated oxidative stress by activation of multiple antioxidant response, in part through Nrf2 pathway.
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Affiliation(s)
- Mohammed Qaisiya
- Fondazione Italiana Fegato ONLUS, Italian Liver Foundation ONLUS, Bldg Q AREA Science Park - Basovizza Campus, 34149 Trieste, Italy.
| | - Carlos Daniel Coda Zabetta
- Fondazione Italiana Fegato ONLUS, Italian Liver Foundation ONLUS, Bldg Q AREA Science Park - Basovizza Campus, 34149 Trieste, Italy.
| | - Cristina Bellarosa
- Fondazione Italiana Fegato ONLUS, Italian Liver Foundation ONLUS, Bldg Q AREA Science Park - Basovizza Campus, 34149 Trieste, Italy.
| | - Claudio Tiribelli
- Fondazione Italiana Fegato ONLUS, Italian Liver Foundation ONLUS, Bldg Q AREA Science Park - Basovizza Campus, 34149 Trieste, Italy; Department of Medical Sciences, University of Trieste, 34100 Trieste, Italy.
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20
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Samokhvalov V, Alsaleh N, El-Sikhry HE, Jamieson KL, Chen CB, Lopaschuk DG, Carter C, Light PE, Manne R, Falck JR, Seubert JM. Epoxyeicosatrienoic acids protect cardiac cells during starvation by modulating an autophagic response. Cell Death Dis 2013; 4:e885. [PMID: 24157879 PMCID: PMC3920965 DOI: 10.1038/cddis.2013.418] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2013] [Revised: 09/21/2013] [Accepted: 09/26/2013] [Indexed: 12/25/2022]
Abstract
Epoxyeicosatrienoic acids (EETs) are cytochrome P450 epoxygenase metabolites of arachidonic acid involved in regulating pathways promoting cellular protection. We have previously shown that EETs trigger a protective response limiting mitochondrial dysfunction and reducing cellular death. Considering it is unknown how EETs regulate cell death processes, the major focus of the current study was to investigate their role in the autophagic response of HL-1 cells and neonatal cardiomyocytes (NCMs) during starvation. We employed a dual-acting synthetic analog UA-8 (13-(3-propylureido)tridec-8-enoic acid), possessing both EET-mimetic and soluble epoxide hydrolase (sEH) inhibitory properties, or 14,15-EET as model EET molecules. We demonstrated that EETs significantly improved viability and recovery of starved cardiac cells, whereas they lowered cellular stress responses such as caspase-3 and proteasome activities. Furthermore, treatment with EETs resulted in preservation of mitochondrial functional activity in starved cells. The protective effects of EETs were abolished by autophagy-related gene 7 (Atg7) short hairpin RNA (shRNA) or pharmacological inhibition of autophagy. Mechanistic evidence demonstrated that sarcolemmal ATP-sensitive potassium channels (pmKATP) and enhanced activation of AMP-activated protein kinase (AMPK) played a crucial role in the EET-mediated effect. Our data suggest that the protective effects of EETs involve regulating the autophagic response, which results in a healthier pool of mitochondria in the starved cardiac cells, thereby representing a novel mechanism of promoting survival of cardiac cells. Thus, we provide new evidence highlighting a central role of the autophagic response in linking EETs with promoting cell survival during deep metabolic stress such as starvation.
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Affiliation(s)
- V Samokhvalov
- Faculty of Pharmacy and Pharmaceutical Sciences, University of Alberta, Edmonton, Alberta, Canada
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21
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Cytochrome P450 2A5 and bilirubin: Mechanisms of gene regulation and cytoprotection. Toxicol Appl Pharmacol 2013; 270:129-38. [DOI: 10.1016/j.taap.2013.04.013] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2013] [Revised: 04/16/2013] [Accepted: 04/18/2013] [Indexed: 12/19/2022]
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22
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Anwar-Mohamed A, Abdelhamid G, Amara IEA, El-Kadi AOS. Differential modulation of cytochrome P450 1a1 by arsenite in vivo and in vitro in C57BL/6 mice. Free Radic Biol Med 2013; 58:52-63. [PMID: 23369756 DOI: 10.1016/j.freeradbiomed.2013.01.012] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/12/2012] [Revised: 01/14/2013] [Accepted: 01/22/2013] [Indexed: 10/27/2022]
Abstract
Heavy metals, typified by arsenite (As(III)), have been implicated in altering the carcinogenicity of aryl hydrocarbon receptor (AhR) ligands, typified by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), by modulating the induction of the Cyp1a1 enzyme, but the mechanism remains unresolved. In this study, the effects of As(III) on Cyp1a1 expression and activity were investigated in C57BL/6 mouse livers and isolated hepatocytes. For this purpose, C57BL/6 mice were injected intraperitoneally with As(III) (12.5 mg/kg) in the absence and presence of TCDD (15 μg/kg) for 6 and 24 h. Furthermore, isolated hepatocytes from C57BL/6 mice were treated with As(III) (1, 5, and 10 μM) in the absence and presence of TCDD (1 nM) for 3, 6, 12, and 24 h. At the in vivo level, As(III) decreased the TCDD-mediated induction of Cyp1a1 mRNA at 6h while potentiating its mRNA, protein, and catalytic activity levels at 24 h. At the in vitro level, As(III) decreased the TCDD-mediated induction of Cyp1a1 mRNA in a concentration- and time-dependent manner. Moreover, As(III) decreased the TCDD-mediated induction of Cyp1a1 protein and catalytic activity levels at 24 h. Interestingly, As(III) increased the serum hemoglobin (Hb) levels in animals treated for 24 h. Upon treatment of isolated hepatocytes with Hb alone, there was an increase in the nuclear accumulation of AhR and AhR-dependent luciferase activity. Furthermore, Hb potentiated the TCDD-induced AhR-dependent luciferase activity. Importantly, when isolated hepatocytes were treated for 5h with As(III) in the presence of TCDD and the medium was then replaced with new medium containing Hb, there was potentiation of the TCDD-mediated effect. Taken together, these results demonstrate for the first time that there is a differential modulation of the TCDD-mediated induction of Cyp1a1 by As(III) in C57BL/6 mouse livers and isolated hepatocytes. Thus, this study implicates Hb as an in vivo-specific modulator.
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Affiliation(s)
- Anwar Anwar-Mohamed
- Faculty of Pharmacy and Pharmaceutical Sciences, University of Alberta, Edmonton, AB, Canada T6G 2E1
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23
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Qadhi R, Alsaleh N, Samokhvalov V, El-Sikhry H, Bellenger J, Seubert JM. Differential responses to docosahexaenoic acid in primary and immortalized cardiac cells. Toxicol Lett 2013; 219:288-97. [PMID: 23523905 DOI: 10.1016/j.toxlet.2013.03.010] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2013] [Revised: 03/10/2013] [Accepted: 03/13/2013] [Indexed: 02/01/2023]
Abstract
The importance of dietary polyunsaturated fatty acids (PUFAs) in the reduction of cardiovascular disease has been recognized for many years. Docosahexaenoic acid (22:6n3, DHA) is an n-3 PUFA known to affect numerous biological functions and provide cardioprotection; however, the exact molecular and cellular protective mechanism(s) remain unknown. In contrast, DHA also possesses many anti-tumorgenic properties including suppressing cell growth and inducing apoptosis. In the present study, we investigated the effect of DHA toward H9c2 cells (an immortalized cardiac cell line) and neonatal primary cardiomyocytes (NCM). Cells were treated with 0μM, 10μM or 100μM DHA for upto 48h. Cell viability and mitochondrial activity were assayed at different time points. DHA caused a significant time- and dose-dependent decrease in cell viability and mitochondrial activity in H9c2 cells but not NCM. In addition, DHA decreased levels of TGF-β1 but increased IL-6 release in H9c2 cells. Significant induction of apoptosis was observed only in H9c2 cells, which involved activation of caspase-8 and -3 activities with a marked release of cytochrome c from mitochondria. DHA-induced severe mitochondrial damage resulting in a fragmented and punctated morphology with corresponding loss of mitochondrial membrane potential within 3h, prior to activation of caspases and cytochrome c release at 6h in H9c2 cells. Our data indicate that DHA treatment targets mitochondria, triggering collapse of mitochondrial membrane potential, increasing cellular stress and mitochondrial fragmentation resulting in apoptosis in immortalized cardiac cells, H9c2, but not neonatal primary cardiomyocyte.
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Affiliation(s)
- Rawabi Qadhi
- Faculty of Pharmacy and Pharmaceutical Sciences, University of Alberta, Edmonton, AB, Canada
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24
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Kapitulnik J, Benaim C, Sasson S. Endothelial Cells Derived from the Blood-Brain Barrier and Islets of Langerhans Differ in their Response to the Effects of Bilirubin on Oxidative Stress Under Hyperglycemic Conditions. Front Pharmacol 2012; 3:131. [PMID: 22811666 PMCID: PMC3396126 DOI: 10.3389/fphar.2012.00131] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2012] [Accepted: 06/21/2012] [Indexed: 12/04/2022] Open
Abstract
Unconjugated bilirubin (UCB) is a neurotoxic degradation product of heme. Its toxic effects include induction of apoptosis, and ultimately neuronal cell death. However, at low concentrations, UCB is a potent antioxidant that may protect cells and tissues against oxidative stress by neutralizing toxic metabolites such as reactive oxygen species (ROS). High glucose levels (hyperglycemia) generate reactive metabolites. Endothelial cell dysfunction, an early vascular complication in diabetes, has been associated with hyperglycemia-induced oxidative stress. Both glucose and UCB are substrates for transport proteins in microvascular endothelial cells of the blood-brain barrier (BBB). In the current study we show that UCB (1–40 μM) induces apoptosis and reduces survival of bEnd3 cells, a mouse brain endothelial cell line which serves as an in vitro model of the BBB. These deleterious effects of UCB were enhanced in the presence of high glucose (25 mM) levels. Interestingly, the bEnd3 cells exhibited an increased sensitivity to the apoptotic effects of UCB when compared to the MS1 microcapillary endothelial cell line. MS1 cells originate from murine pancreatic islets of Langerhans, and are devoid of the barrier characteristics of BBB-derived endothelial cells. ROS production was increased in both bEnd3 and MS1 cells exposed to high glucose, as compared with cells exposed to normal (5.5 mM) glucose levels. While UCB (0.1–40 μM) did not alter ROS production in cells exposed to normal glucose, relatively low (“physiological”) UCB concentrations (0.1–5 μM) attenuated ROS generation in both cell lines exposed to high glucose levels. Most strikingly, higher UCB concentrations (20–40 μM) increased ROS generation in bEnd3 cells exposed to high glucose, but not in similarly treated MS1 cells. These results may be of critical importance for understanding the vulnerability of the BBB endothelium upon exposure to increasing UCB levels under hyperglycemic conditions.
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Affiliation(s)
- Jaime Kapitulnik
- Department of Pharmacology, Institute of Drug Research, School of Pharmacy, The Hebrew University of Jerusalem Jerusalem, Israel
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25
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Khan NM, Poduval TB. Immunomodulatory and immunotoxic effects of bilirubin: molecular mechanisms. J Leukoc Biol 2011; 90:997-1015. [PMID: 21807743 DOI: 10.1189/jlb.0211070] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
The immunomodulatory and immunotoxic effects of purified UCB have not been evaluated previously at clinically relevant UCB concentrations and UCB:BSA ratios. To delineate the molecular mechanism of UCB-induced immunomodulation, immune cells were exposed to clinically relevant concentrations of UCB. It inhibited LPS-induced B cell proliferation and cytokine production from splenic macrophages. UCB (≥25 μM) was toxic to unfractionated splenocytes, splenic T cells, B cells, macrophages, LPS-stimulated CD19(+) B cells, human PBMCs, and RBCs. Purified UCB also was found to be toxic to splenocytes and human PBMCs. UCB induced necrosis and apoptosis in splenocytes. UCB activated the extrinsic and intrinsic pathways of apoptosis, as reflected by the markers, such as CD95, caspase-8, Bax, MMP, cytoplasmic Ca(+2), caspase-3, and DNA fragmentation. UCB depleted GSH and activated p38MAPK. NAC, caspase inhibitors, and p38MAPK inhibitor attenuated the UCB-induced apoptosis. In vivo administration of ≥25 mg/kbw UCB induced atrophy of spleen, depletion of bone marrow cells, and leukopenia and decreased lymphocyte count and the T and B cell response to mitogens. UCB administration to mice led to induction of oxidative stress, activation of p38MAPK, and cell death in splenocytes. These parameters were attenuated by the injection of NAC and the p38MAPK inhibitor. Our results demonstrate for the first time that clinically relevant concentrations of UCB induce apoptosis and necrosis in immune cells by depleting cellular GSH. These findings should prove useful in understanding the immunosuppression associated with hyperbilirubinemia.
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Affiliation(s)
- Nazir M Khan
- Radiation Biology and Health Sciences Division, Bhabha Atomic Research Centre, Trombay, Mumbai, India
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Oakes GH, Bend JR. Global changes in gene regulation demonstrate that unconjugated bilirubin is able to upregulate and activate select components of the endoplasmic reticulum stress response pathway. J Biochem Mol Toxicol 2010; 24:73-88. [PMID: 20196124 DOI: 10.1002/jbt.20313] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Elevated concentrations of unconjugated bilirubin (UCB) are responsible for neonatal jaundice and can eventually lead to kernicterus or death. The molecular mechanism of UCB toxicity is incompletely elucidated. The purpose of this study was to analyze changes in gene regulation mediated by UCB to determine novel pathways that contribute to UCB-mediated toxicity. We employed microarray analysis to determine changes in gene regulation mediated by UCB at both pro- (50 microM) and antioxidant (70 nM) concentrations in Hepa 1c1c7 cells at 1 and 6 h. The changes observed in select genes were validated with qPCR. Using immunoblot analysis, we validated these changes at the protein level for select genes and documented the activation of two proteins involved in the endoplasmic reticulum (ER) stress pathway, eIF2 alpha and PERK. Following treatment with 50 microM UCB, microarray analysis revealed the upregulation of many genes involved in ER stress (ATF3, BiP, CHOP, Dnajb1, and Herp). We demonstrate that upregulation of the proapoptotic transcription factor CHOP results in increased intracellular protein content. It was determined that activation of proteins involved in ER stress was an early event in UCB toxicity as eIF2 alpha and PERK were both phosphorylated and activated by 1 h posttreatment. We also demonstrate that procaspase-12 content, a proposed initiator caspase in ER stress-mediated apoptosis, is decreased by 4 h posttreatment. In conclusion, this study demonstrates that elevated concentrations of UCB (50 microM) are able to activate select components of the ER stress pathway in Hepa 1c1c7 cells, which may contribute to UCB-mediated apoptosis.
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Affiliation(s)
- Garth H Oakes
- Department of Physiology & Pharmacology, Siebens-Drake Medical Research Institute, Schulich School of Medicine & Dentistry, University of Western Ontario, 1400 Western Road, London, Ontario, Canada
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Calligaris R, Bellarosa C, Foti R, Roncaglia P, Giraudi P, Krmac H, Tiribelli C, Gustincich S. A transcriptome analysis identifies molecular effectors of unconjugated bilirubin in human neuroblastoma SH-SY5Y cells. BMC Genomics 2009; 10:543. [PMID: 19925663 PMCID: PMC2789749 DOI: 10.1186/1471-2164-10-543] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2009] [Accepted: 11/19/2009] [Indexed: 01/23/2023] Open
Abstract
BACKGROUND The deposition of unconjugated bilirubin (UCB) in selected regions of the brain results in irreversible neuronal damage, or Bilirubin Encephalopathy (BE). Although UCB impairs a large number of cellular functions in other tissues, the basic mechanisms of neurotoxicity have not yet been fully clarified. While cells can accumulate UCB by passive diffusion, cell protection may involve multiple mechanisms including the extrusion of the pigment as well as pro-survival homeostatic responses that are still unknown. RESULTS Transcriptome changes induced by UCB exposure in SH-SY5Y neuroblastoma cell line were examined by high density oligonucleotide microarrays. Two-hundred and thirty genes were induced after 24 hours. A Gene Ontology (GO) analysis showed that at least 50 genes were directly involved in the endoplasmic reticulum (ER) stress response. Validation of selected ER stress genes is shown by quantitative RT-PCR. Analysis of XBP1 splicing and DDIT3/CHOP subcellular localization is presented. CONCLUSION These results show for the first time that UCB exposure induces ER stress response as major intracellular homeostasis in surviving neuroblastoma cells in vitro.
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Elbekai RH, Korashy HM, Wills K, Gharavi N, El-Kadi AOS. Benzo[a]Pyrene, 3-Methylcholanthrene and ß-Naphthoflavone Induce Oxidative Stress in Hepatoma Hepa 1c1c7 Cells by an AHR-dependent Pathway. Free Radic Res 2009; 38:1191-200. [PMID: 15621696 DOI: 10.1080/10715760400017319] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Polycyclic aromatic hydrocarbons have been shown to cause oxidative stress in vitro and in vivo in various animal models but the mechanisms by which these compounds produce oxidative stress are unknown. In the current study we have investigated the role of the aryl hydrocarbon receptor (AHR) in the production of reactive oxygen species (ROS) by its cognate ligands and the consequent effect on cyp1a1 activity, mRNA and protein expressions. For this purpose, Hepa 1c1c7 cells wild-type (WT) and C12 mutant cells, which are AHR-deficient, were incubated with increasing concentrations of the AHR-ligands, benzo[a]pyrene (B[a]P, 0.25-25 microM), 3-methylcholanthrene (3MC, 0.1-10 microM) and beta-naphthoflavone (betaNF, 1-50 microM). The studied AHR-ligands dose-dependently increased lipid peroxidation in WT but not in C12 cells. However, only B[a]P and betaNF, at the highest concentrations tested, significantly increased H2O2 production in WT but not C12 cells. The increase in lipid peroxidation and H2O2 production by AHR-ligands were accompanied by a decrease in the cyp1a1 catalytic activity but not mRNA or protein expressions, which were significantly induced in a dose-dependent manner by all AHR-ligands, suggesting a post-translational mechanism is involved in the decrease of cyp1a1 activity. The AHR-ligand-mediated decrease in cyp1a1 activity was reversed by the antioxidant N-acetylcysteine. Our results show that the AHR-ligands induce oxidative stress by an AHR-dependent pathway.
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Affiliation(s)
- Reem H Elbekai
- Faculty of Pharmacy and Pharmaceutical Sciences, 3118, Dentistry/Pharmacy Centre, University of Alberta, Edmonton, Alberta T6G 2N8, Canada
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Zhang Y, El-Sikhry H, Chaudhary KR, Batchu SN, Shayeganpour A, Jukar TO, Bradbury JA, Graves JP, DeGraff LM, Myers P, Rouse DC, Foley J, Nyska A, Zeldin DC, Seubert JM. Overexpression of CYP2J2 provides protection against doxorubicin-induced cardiotoxicity. Am J Physiol Heart Circ Physiol 2009; 297:H37-46. [PMID: 19429816 DOI: 10.1152/ajpheart.00983.2008] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Human cytochrome P-450 (CYP)2J2 is abundant in heart and active in biosynthesis of epoxyeicosatrienoic acids (EETs). Recently, we demonstrated that these eicosanoid products protect myocardium from ischemia-reperfusion injury. The present study utilized transgenic (Tr) mice with cardiomyocyte-specific overexpression of human CYP2J2 to investigate protection toward toxicity resulting from acute (0, 5, or 15 mg/kg daily for 3 days, followed by 24-h recovery) or chronic (0, 1.5, or 3.0 mg/kg biweekly for 5 wk, followed by 2-wk recovery) doxorubicin (Dox) administration. Acute treatment resulted in marked elevations of serum lactate dehydrogenase and creatine kinase levels that were significantly greater in wild-type (WT) than CYP2J2 Tr mice. Acute treatment also resulted in less activation of stress response enzymes in CYP2J2 Tr mice (catalase 750% vs. 300% of baseline, caspase-3 235% vs. 165% of baseline in WT vs. CYP2J2 Tr mice). Moreover, CYP2J2 Tr hearts exhibited less Dox-induced cardiomyocytes apoptosis (measured by TUNEL) compared with WT hearts. After chronic treatment, comparable decreases in body weight were observed in WT and CYP2J2 Tr mice. However, cardiac function, assessed by measurement of fractional shortening with M-mode transthoracic echocardiography, was significantly higher in CYP2J2 Tr than WT hearts after chronic Dox treatment (WT 37 +/- 2%, CYP2J2 Tr 47 +/- 1%). WT mice also had larger increases in beta-myosin heavy chain and cardiac ankryin repeat protein compared with CYP2J2 Tr mice. CYP2J2 Tr hearts had a significantly higher rate of Dox metabolism than WT hearts (2.2 +/- 0.25 vs. 1.6 +/- 0.50 ng.min(-1).100 microg protein(-1)). In vitro data from H9c2 cells demonstrated that EETs attenuated Dox-induced mitochondrial damage. Together, these data suggest that cardiac-specific overexpression of CYP2J2 limited Dox-induced toxicity.
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Affiliation(s)
- Yunfang Zhang
- Faculty of Pharmacy and Pharmaceutical Sciences, University of Alberta, Edmonton, Alberta, Canada
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Kumar S, Guha M, Choubey V, Maity P, Srivastava K, Puri SK, Bandyopadhyay U. Bilirubin inhibits Plasmodium falciparum growth through the generation of reactive oxygen species. Free Radic Biol Med 2008; 44:602-13. [PMID: 18070610 DOI: 10.1016/j.freeradbiomed.2007.10.057] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/03/2007] [Revised: 09/28/2007] [Accepted: 10/17/2007] [Indexed: 11/25/2022]
Abstract
Free heme is very toxic because it generates highly reactive hydroxyl radicals ((.)OH) to cause oxidative damage. Detoxification of free heme by the heme oxygenase (HO) system is a very common phenomenon by which free heme is catabolized to form bilirubin as an end product. Interestingly, the malaria parasite, Plasmodium falciparum, lacks an HO system, but it forms hemozoin, mainly to detoxify free heme. Here, we report that bilirubin significantly induces oxidative stress in the parasite as evident from the increased formation of lipid peroxide, decrease in glutathione content, and increased formation of H(2)O(2) and (.)OH. Bilirubin can effectively inhibit hemozoin formation also. Furthermore, results indicate that bilirubin inhibits parasite growth and induces caspase-like protease activity, up-regulates the expression of apoptosis-related protein (Gene ID PFI0450c), and reduces the mitochondrial membrane potential. (.)OH scavengers such as mannitol, as well as the spin trap alpha-phenyl-n-tert-butylnitrone, effectively protect the parasite from bilirubin-induced oxidative stress and growth inhibition. These findings suggest that bilirubin, through the development of oxidative stress, induces P. falciparum cell death and that the malaria parasite lacks an HO system probably to protect itself from bilirubin-induced cell death as a second line of defense.
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Affiliation(s)
- Sanjay Kumar
- Drug Target Discovery and Development Division, Central Drug Research Institute, Mahatma Gandhi Marg, Lucknow 226001, Uttar Pradesh, India
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Lin HY, Shen SC, Lin CW, Yang LY, Chen YC. Baicalein inhibition of hydrogen peroxide-induced apoptosis via ROS-dependent heme oxygenase 1 gene expression. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2007; 1773:1073-86. [PMID: 17532486 DOI: 10.1016/j.bbamcr.2007.04.008] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2006] [Revised: 04/08/2007] [Accepted: 04/09/2007] [Indexed: 12/30/2022]
Abstract
In the present study, baicalein (BE) but not its glycoside, baicalin (BI), induced heme oxygenase-1 (HO-1) gene expression at both the mRNA and protein levels, and the BE-induced HO-1 protein was blocked by adding cycloheximide (CHX) or actinomycin D (Act D). Activation of ERK, but not JNK or p38, proteins via induction of phosphorylation in accordance with increasing intracellular peroxide levels was detected in BE-treated RAW264.7 macrophages. The addition of the ERK inhibitor, PD98059, (but not the p38 inhibitor, SB203580, or the JNK inhibitor, SP600125) and the chemical antioxidant, N-acetyl cysteine (NAC), significantly reduced BE-induced HO-1 protein expression by respectively blocking ERK protein phosphorylation and intracellular peroxide production. Additionally, BE but not BI effectively protected RAW264.7 cells from hydrogen peroxide (H(2)O(2))-induced cytotoxicity, and the preventive effect was attenuated by the addition of the HO inhibitor, SnPP, and the ERK inhibitor, PD98059. H(2)O(2)-induced apoptotic events including hypodiploid cells, DNA fragmentation, activation of caspase 3 enzyme activity, and a loss in the mitochondrial membrane potential with the concomitant release of cytochrome c from mitochondria to the cytosol were suppressed by the addition of BE but not BI. Blocking HO-1 protein expression by the HO-1 antisense oligonucleotide attenuated the protective effect of BE against H(2)O(2)-induced apoptosis by suppressing HO-1 gene expression in macrophages. Overexpression of the HO-1 protein inhibited H(2)O(2)-induced apoptotic events such as DNA fragmentation and hypodiploid cells by reducing intracellular peroxide production induced by H(2)O(2), compared with those events in neo-control (neo-RAW264.7) cells. In addition, CO, but not bilirubin and biliverdin, addition inhibits H(2)O(2)-induced cytotoxicity in macrophages. It suggests that CO can be responsible for the protective effect associated with HO-1 overexpression. The notion of induction of HO-1 gene expression through a ROS-dependent manner suppressing H(2)O(2)-induced cell death is identified in the present study.
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Affiliation(s)
- Hui-Yi Lin
- Graduate Institute of Pharmacy, School of Pharmacy, Taipei Medical University, Taipei, Taiwan
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Ljungdahl M, Osterberg J, Ransjö U, Engstrand L, Haglund U. Inflammatory response in patients with malignant obstructive jaundice. Scand J Gastroenterol 2007; 42:94-102. [PMID: 17190769 DOI: 10.1080/00365520600825190] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
OBJECTIVE Surgery in patients with malignant obstructive jaundice is associated with increased risks for postoperative septic complications. The aim of this study was to investigate the inflammatory and the local cellular immune response in patients accepted for surgery because of tumours in the hepatic-pancreatic-biliary (HPB) tract. MATERIAL AND METHODS Patients with obstructive jaundice (group HPB(+)) were compared with those without (HPB(-)). Patients undergoing surgery for benign abdominal disorders served as controls. Obstructive jaundice was present in 18 out of 33 HPB patients. Preoperatively, blood was analysed for bacteria, endotoxins and cytokines (TNF-alpha, IL-6 and IL-10). At operation, mesenteric lymph nodes (MLNs) were excised for bacterial cultures using standard microbiological techniques, and immunohistochemistry, using antibodies CD4 and CD8 (mainly staining T lymphocytes), CD68 (macrophages), and anti-caspase-3 (to determine the rate of apoptosis). RESULTS Bacterial translocation was not demonstrated in any of the patients. Increased preoperative concentrations of endotoxins were found in group HPB(+). The number of macrophages and the rate of apoptosis in MLNs were increased in jaundiced patients, while the number of T lymphocytes was decreased. CONCLUSIONS Malignant obstructive jaundice causes increased blood concentrations of endotoxins and cytokines, an increased number of macrophages in MLNs, a higher rate of apoptosis in MLNs, but a decreased number of T lymphocytes in MLNs. The lymphocyte depletion is probably due to the increased rate of apoptosis, and might reduce the ability of jaundiced patients to eradicate infection.
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Indrio F, Raimondi F, Laforgia N, Riezzo G, Polimeno L, Francavilla R. Effect of hyperbilirubinemia on intestinal permeability in healthy term newborns. Acta Paediatr 2007; 96:73-5. [PMID: 17187608 DOI: 10.1111/j.1651-2227.2006.00007.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
UNLABELLED We investigated the effect of serum bilirubin (SB) on intestinal permeability (IP) of healthy, term, birth weight appropriate for gestational age neonates before phototherapy. IP was measured by the dual probe (lactulose/mannitol) sugar absorption test (SAT) performed on the third day of life in 12 healthy jaundiced newborns (total bilirubin 249 +/- 39.75 micromol/L) and compared to that of 12 non-jaundiced newborns (total bilirubin 83.79 + 37.62 micromol/L) matched for sex, gestational age, birth weight and Apgar score. Jaundiced newborns have a significantly higher La/Ma ratio than non-jaundiced (0.31 +/- 0.28 vs. 0.053 +/- 0.043; p < 0.0004). A significant correlation was found between serum bilirubin level and La/Ma ratio (r = 0.56 p < 0.006). CONCLUSION Our study demonstrates a direct effect of UCB on gut epithelial barrier of at-term newborns in whom UCB appears to be responsible for an alteration of IP that theoretically may lead to a passage of macromolecules through the intestinal epithelium increasing the risk of sensitization.
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Affiliation(s)
- Flavia Indrio
- Department of Pediatrics, Neonatology Section, University of Bari, Bari I-70124, Italy.
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Hankø E, Hansen TWR, Almaas R, Rootwelt T. Recovery after short-term bilirubin exposure in human NT2-N neurons. Brain Res 2006; 1103:56-64. [PMID: 16814266 DOI: 10.1016/j.brainres.2006.05.083] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2005] [Revised: 05/13/2006] [Accepted: 05/17/2006] [Indexed: 11/25/2022]
Abstract
We used human NT2-N neurons to investigate delayed effects of short-term exposure to unconjugated bilirubin (UCB). Cell viability was evaluated with MTT reduction assays and nuclear morphology. A 6-h exposure to 1, 5, or 25 microM UCB and serum deprivation (SED) significantly diminished MTT reduction. 96 h after rescue of neurons with removal of UCB and re-incubation in the original serum-containing medium, delayed effects were evident as recovery (1 microM UCB), intermediate cell death (5 microM UCB), or near complete cell death (25 microM UCB). The impact of 6 h of SED alone appeared to be modest in rescued neurons. In this model, co-treatment with the specific caspase-3 inhibitor, zDEVD.FMK (100 microM), or the pancaspase inhibitor zVAD.FMK (100 microM) did not improve viability in rescued neurons exposed to 5 microM UCB, while treatment with the NMDA receptor antagonist MK-801 (1 microM) enhanced the number of undamaged nuclei (86 +/- 14% versus 50 +/- 12%, P = 0.001). MK-801 had, however, no impact on MTT reduction. In a different model with a 102-h continuous exposure to UCB and SED, we found a significant additional toxic impact of serum deprivation. Separate experiments suggested that this was a result of late caspase-mediated toxicity. We conclude that UCB-mediated effects may be reversible in this model. Blockade of excitotoxic mechanisms, but not caspase activity may prevent delayed cell death.
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Affiliation(s)
- Erik Hankø
- Department of Pediatric Research, Rikshospitalet-Radiumhospitalet Medical Center, University of Oslo, Oslo, Norway.
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Tiribelli C, Ostrow JD. The molecular basis of bilirubin encephalopathy and toxicity: report of an EASL Single Topic Conference, Trieste, Italy, 1-2 October, 2004. J Hepatol 2005; 43:156-66. [PMID: 15921815 DOI: 10.1016/j.jhep.2005.04.003] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Affiliation(s)
- Claudio Tiribelli
- Centro Studi Fegato, Bldg. Q, AREA Science Park, Basovizza and Department of BBCM, University of Trieste, 34012 Trieste, Italy.
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Rigato I, Ostrow JD, Tiribelli C. Bilirubin and the risk of common non-hepatic diseases. Trends Mol Med 2005; 11:277-83. [PMID: 15949769 DOI: 10.1016/j.molmed.2005.04.008] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2005] [Revised: 04/22/2005] [Accepted: 04/29/2005] [Indexed: 12/29/2022]
Abstract
Bilirubin is a potent antioxidant but can be toxic at high concentrations. This article critically reviews the reported relationships of plasma bilirubin levels to the severity and/or incidence of various common non-hepatic diseases. Plasma bilirubin levels are reportedly negatively related to the risk of atherosclerotic diseases, cancers, demyelinating neuropathies and seasonal affective disorder. By contrast, the incidence and severity of schizophrenia are increased by elevated bilirubin levels. The data strongly suggest that the level of plasma bilirubin should be considered as a risk factor for several common non-hepatic diseases. Additional studies are needed to clarify the mechanisms of this influence, which are thought to be related to unconjugated bilirubin counteracting the oxidative stress underlying these disorders.
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Affiliation(s)
- Igino Rigato
- Centro Studi Fegato, Bldg. Q, AREA Science Park, Basovizza, Italy
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Fong CJ, Burgoon LD, Zacharewski TR. Comparative microarray analysis of basal gene expression in mouse Hepa-1c1c7 wild-type and mutant cell lines. Toxicol Sci 2005; 86:342-53. [PMID: 15888666 DOI: 10.1093/toxsci/kfi194] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Hepa-1c1c7 wild-type and benzo[a]pyrene-resistant derived mutant cell lines have been used to elucidate pathways and mechanisms involving the aryl hydrocarbon receptor (AhR). However, there has been little focus on other biological processes which may differ between the isolated lines. In this study, mouse cDNA microarrays representing 4858 genes were used to examine differences in basal gene expression between mouse Hepa-1c1c7 wild-type and c1 (truncated Cyp1a1 protein), c4 (AhR nuclear translocator, ARNT, deficient), and c12 (low AhR levels) mutant cell lines. Surprisingly, c1 mutants exhibited the greatest number of gene expression changes compared to wild-type cells, followed by c4 and c12 lines, respectively. Differences in basal gene expression were consistent with cell line specific variations in morphology, mitochondrial activity, and proliferation rate. MTT and direct cell count assays indicate both c4 and c12 mutants exhibit increased proliferative activity when compared to wild-type cells, while the c1 mutants exhibited decreased activity. This study further characterizes Hepa-1c1c7 wild-type and mutant cells and identifies significant differences in biological processes that should be considered when conducting comparative mechanistic studies with these lines.
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Affiliation(s)
- C J Fong
- Department of Biochemistry and Molecular Biology, National Food Safety and Toxicology Center, Michigan State University, East Lansing, Michigan 48824, USA
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Abstract
Studies on primary cultures of newborn rodent neurons have suggested that neuronal death induced by unconjugated bilirubin (UCB) is mainly apoptotic in nature. We exposed a human teratocarcinoma-derived cell line, NT2-N neurons, to different concentrations of UCB and albumin at a 1.5 molar ratio and used multiple, independent measures of cell damage to evaluate neuronal injury after 6, 24, and 48 h. Low doses of UCB (0.66, 2, and 5 microM) induced a moderate loss of 3-4[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazoliumbromide (MTT) cleavage accompanied by delayed morphologic changes consistent with apoptosis (2 and 5 microM). Moderate concentrations of UCB (10 and 25 microM) resulted in early (6 h) necrosis in a subset of neurons, while remaining neurons underwent progressive impairment of MTT cleavage and increasing lactate dehydrogenase (LDH) release accompanied by predominantly delayed apoptosis. High concentrations of UCB (100 microM) induced severe impairment of MTT cleavage, extensive LDH release, and morphologic changes consistent with necrosis within 6 h. Used as a positive control for apoptosis, 2 microM STS induced progressive impairment of MTT cleavage and morphologic changes consistent with apoptosis over the entire observation period. DNA electrophoresis at 48 h was compatible with apoptosis both after treatment with STS and UCB concentrations <or=25, but not at 100 microM. Cleavage of poly (ADP-ribose) polymerase (PARP) was only seen in neurons treated with low UCB concentrations and STS. We conclude that UCB induces early necrosis at high and moderate concentrations and predominantly delayed apoptosis at low and moderate concentrations in cultured human NT2-N neurons.
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Affiliation(s)
- Erik Hankø
- Department of Pediatric Research, Oslo, Norway.
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Oakes GH, Bend JR. Early steps in bilirubin-mediated apoptosis in murine hepatoma (Hepa 1c1c7) cells are characterized by aryl hydrocarbon receptor-independent oxidative stress and activation of the mitochondrial pathway. J Biochem Mol Toxicol 2005; 19:244-55. [PMID: 16173058 DOI: 10.1002/jbt.20086] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Unconjugated bilirubin (UCB), the end product of heme catabolism, causes apoptosis in cells of the central nervous system, endothelial cells, and hepatotoma cells. However, the molecular mechanisms that contribute to UCB cytotoxicity remain unclear. The purpose of this study was to characterize the sequence of early events leading to UCB-mediated cytotoxicity in murine hepatoma Hepa 1c1c7 cells. In the present study, UCB (5-50 microM) was found to markedly increase the intracellular generation of reactive oxygen species (ROS) in a concentration-dependent manner, which is significantly elevated by 30 min post-treatment. This generation of ROS by UCB is not dependent on aryl hydrocarbon receptor (Ahr) signaling, as cells deficient in the Ahr (C12 cells) or the Ahr nuclear translocator protein (Arnt; C4 cells) were as efficient at generating ROS as wild type (WT) Hepa 1c1c7 cells. Mitochondrial membrane depolarization, evaluated with the lipophilic cationic dye, JC-1, occurred at least by 2 h after treatment with 50 muM UCB. Analysis of the caspase cascade demonstrated that activation of caspase-9 preceded activation of caspase-3. No conversion of procaspase-2 to active caspase-2 was detected in this study. These results demonstrate that UCB-mediated apoptosis in Hepa 1c1c7 cells is associated with increased oxidative stress and that caspase-9, and definitely not caspase-2, is the initiator caspase for apoptosis in UCB-treated Hepa 1c1c7 cells.
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Affiliation(s)
- Garth H Oakes
- Department of Physiology & Pharmacology, Schulich School of Medicine & Dentistry, University of Western Ontario, London, Ontario, Canada N6A 5C1
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Keshavan P, Schwemberger SJ, Smith DLH, Babcock GF, Zucker SD. Unconjugated bilirubin induces apoptosis in colon cancer cells by triggering mitochondrial depolarization. Int J Cancer 2004; 112:433-45. [PMID: 15382069 DOI: 10.1002/ijc.20418] [Citation(s) in RCA: 91] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Bilirubin is the principal end product of heme degradation. Prompted by epidemiologic analyses demonstrating an inverse correlation between serum bilirubin levels and cancer mortality, we examined the effect(s) of bilirubin on the growth and survival of colon adenocarcinoma cells. Adenocarcinoma cell monolayers were treated with bilirubin over a range of bilirubin:BSA molar ratios (0-0.6), and viability was assessed colorimetrically. Apoptosis was characterized by TUNEL assay, annexin V staining and caspase-3 activation. The mechanism(s) by which bilirubin induces apoptosis was investigated by Western blotting for cytochrome c release, assaying for caspase-8 and caspase-9 activation and for mitochondrial depolarization by JC-1 staining. The direct effect of bilirubin on the membrane potential of isolated mitochondria was evaluated using light-scattering and fluorescence techniques. Bilirubin decreased the viability of all colon cancer cell lines tested in a dose-dependent manner. Cells exhibited substantial apoptosis when exposed to bilirubin concentrations ranging 0-50 microM, as demonstrated by an 8- to 10-fold increase in TUNEL and annexin V staining and in caspase-3 activity. Bilirubin treatment evokes specific activation of caspase-9, enhances cytochrome c release into the cytoplasm and triggers the mitochondrial permeability transition in colon cancer monolayers. Additionally, bilirubin directly induces the depolarization of isolated rat liver mitochondria, an effect that is not inhibited by cyclosporin A. Bilirubin stimulates apoptosis of colon adenocarcinoma cells in vitro through activation of the mitochondrial pathway, apparently by directly dissipating mitochondrial membrane potential. As this effect is triggered at concentrations normally present in the intestinal lumen, we postulate a physiologic role for bilirubin in modulating colon tumorigenesis.
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Affiliation(s)
- Pavitra Keshavan
- Division of Digestive Diseases, University of Cincinnati, Cincinnati, OH, USA.
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Brito MA, Brites D, Butterfield DA. A link between hyperbilirubinemia, oxidative stress and injury to neocortical synaptosomes. Brain Res 2004; 1026:33-43. [PMID: 15476695 DOI: 10.1016/j.brainres.2004.07.063] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/31/2004] [Indexed: 11/28/2022]
Abstract
Cytotoxicity by unconjugated bilirubin involves disturbances of membrane structure, excitotoxicity and cell death. These events were reported to trigger elevated free radicals production and impairment of calcium homeostasis, and to result in loss of cell membrane integrity. Therefore, this study was designed to investigate whether interaction of clinically relevant concentrations of free unconjugated bilirubin with synaptosomal membrane vesicles could be linked to oxidative stress, cytosolic calcium accumulation and perturbation of membrane function. Synaptosomal vesicles were prepared from gerbil cortical brain tissue and incubated with purified bilirubin (<or=1 microM), for 4 h at 37 degrees C. Intracellular concentrations of reactive oxygen species (ROS) and calcium were determined by dichlorofluorescin and BAPTA fluorescent probes, respectively. Membrane protein and lipid oxidation were evaluated by immunocytochemistry and phosphatidylserine exposure by annexin V binding. Levels of reduced and oxidized glutathione (GSH and GSSG, respectively), as well as activities of Mg(2+)-ATPase aminophospholipid translocase (flippase) and Na(+),K(+)-ATPase, were also measured. Our results showed that bilirubin induced oxidative stress, due to a rise in lipid (>or=10%, P<0.05) and protein oxidation (>or=20%, P<0.01), ROS content (approximately 17%, P<0.01), and a decrease in GSH/GSSG ratio (>30%, P<0.01). In addition, synaptosomes exposed to bilirubin exhibited increased externalization of phosphatidylserine (approximately 10%, P<0.05), together with decreased flippase and NA(+),K(+)-ATPase (>or=15%, P<0.05) activities, events that were accompanied by enhanced intracellular calcium levels ( approximately 20%, P<0.01). The data obtained point out that interaction of unconjugated bilirubin with synaptosomal membrane vesicles leads to oxidative injury, loss of membrane asymmetry and functionality, and calcium intrusion, thus potentially contributing to the pathogenesis of encephalopathy by hyperbilirubinemia.
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Affiliation(s)
- Maria Alexandra Brito
- Centro de Patogénese Molecular--UBMBE, Faculdade de Farmácia, University of Lisbon, Av. das Forças Armadas, 1600-083 Lisbon, Portugal.
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Abstract
Unconjugated bilirubin (UCB), at slightly elevated unbound concentrations, is toxic to astrocytes and neurons, damaging mitochondria (causing impaired energy metabolism and apoptosis) and plasma membranes (causing oxidative damage and disrupting transport of neurotransmitters). Accumulation of UCB in the CSF and CNS is limited by its active export, probably mediated by MRP1/Mrp1 present in choroid plexus epithelia, capillary endothelia, astrocytes and neurons. Upregulation of MRP1/Mrp1 protein levels by UCB might represent an important adaptive mechanism that protects the CNS from UCB toxicity. These concepts could explain the varied susceptibility of newborns to bilirubin neurotoxicity and the occurrence of neurological damage at plasma UCB concentrations well below therapeutic guidelines, and are relevant to the increasing prevalence of bilirubin encephalopathy in newborns.
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Affiliation(s)
- J Donald Ostrow
- Research Service, VA Puget Sound Health Care System-Seattle Division, and GI/Hepatology Division, Department of Medicine, University of Washington School of Medicine, Seattle, WA 98108-1597, USA
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Nakao A, Otterbein LE, Overhaus M, Sarady JK, Tsung A, Kimizuka K, Nalesnik MA, Kaizu T, Uchiyama T, Liu F, Murase N, Bauer AJ, Bach FH. Biliverdin protects the functional integrity of a transplanted syngeneic small bowel. Gastroenterology 2004; 127:595-606. [PMID: 15300591 DOI: 10.1053/j.gastro.2004.05.059] [Citation(s) in RCA: 128] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
BACKGROUND & AIMS Heme oxygenase-1 (HO-1) protects against inflammation in many disease models. By degrading heme, HO-1 generates carbon monoxide (CO), iron and biliverdin. We investigated whether biliverdin would protect rat syngeneic small intestinal transplants (SITx) against damage and, if so, by what mechanism. METHODS Motility was assessed by organ bath techniques. Inflammatory cytokines and mediators were assessed by RT-PCR and spectrophotometric assays. Myeloperoxidase histochemistry for neutrophils was performed in jejunal segments. Western blots were performed for biliverdin reductase and HO-1 expression. Permeability was expressed as the mucosal to serosal clearance of fluorescent dextran in everted gut sacs. NF-kappaB activation was assessed via EMSA. RESULTS Biliverdin significantly improved survival of recipients following SITx after prolonged intestinal ischemia (6 hours). Biliverdin treatment (1) led to a significant decrease in mRNA expression of iNOS, Cox-2, and ICAM-1 as well as the inflammatory cytokines IL-6 and IL-1beta; (2) decreased neutrophil infiltration into the jejunal muscularis; and (3) prevented SITx-induced suppression of intestinal circular muscle contractility. CONCLUSIONS Biliverdin administration attenuates transplantation-induced injuries to the small bowel by its anti-inflammatory action. Importantly, biliverdin enhanced recipient survival. A comparison of the mechanisms by which biliverdin exerted these salutary effects compared with inhalation of CO, which we previously showed had salutary effects, suggests that the 2 compounds (biliverdin and CO) exert their effects in part by different mechanisms. This implies that the different products of HO-1 action on heme may exert protective effects that are additive or synergistic.
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Affiliation(s)
- Atsunori Nakao
- Thomas E. Starzl Transplant Institute, University of Pittsburgh, Pennsylvania, USA
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Kapitulnik J. Bilirubin: an endogenous product of heme degradation with both cytotoxic and cytoprotective properties. Mol Pharmacol 2004; 66:773-9. [PMID: 15269289 DOI: 10.1124/mol.104.002832] [Citation(s) in RCA: 177] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Affiliation(s)
- Jaime Kapitulnik
- Department of Pharmacology, School of Pharmacy, The Hebrew University of Jerusalem, POB 12065, 91120, Israel.
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