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Xue Q, Wang Y, Liu Y, Hua H, Zhou X, Xu Y, Zhang Y, Xiong C, Liu X, Yang K, Huang Y. Dysregulated Glucuronidation of Bilirubin Exacerbates Liver Inflammation and Fibrosis in Schistosomiasis Japonica through the NF-κB Signaling Pathway. Pathogens 2024; 13:287. [PMID: 38668242 PMCID: PMC11054532 DOI: 10.3390/pathogens13040287] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2024] [Revised: 03/16/2024] [Accepted: 03/22/2024] [Indexed: 04/29/2024] Open
Abstract
Hepatic fibrosis is an important pathological manifestation of chronic schistosome infection. Patients with advanced schistosomiasis show varying degrees of abnormalities in liver fibrosis indicators and bilirubin metabolism. However, the relationship between hepatic fibrosis in schistosomiasis and dysregulated bilirubin metabolism remains unclear. In this study, we observed a positive correlation between total bilirubin levels and the levels of ALT, AST, LN, and CIV in patients with advanced schistosomiasis. Additionally, we established mouse models at different time points following S. japonicum infection. As the infection time increased, liver fibrosis escalated, while liver UGT1A1 consistently exhibited a low expression, indicating impaired glucuronidation of bilirubin metabolism in mice. In vitro experiments suggested that SEA may be a key inhibitor of hepatic UGT1A1 expression after schistosome infection. Furthermore, a high concentration of bilirubin activated the NF-κB signaling pathway in L-O2 cells in vitro. These findings suggested that the dysregulated glucuronidation of bilirubin caused by S. japonicum infection may play a significant role in schistosomiasis liver fibrosis through the NF-κB signaling pathway.
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Affiliation(s)
- Qingkai Xue
- National Health Commission Key Laboratory of Parasitic Disease Control and Prevention, Jiangsu Provincial Key Laboratory on Parasite and Vector Control Technology, Jiangsu Institute of Parasitic Diseases, 117 Meiyuan Yangxiang, Wuxi 214064, China; (Q.X.)
- Experimental Center of Clinical Research, The First Affiliated Hospital of Anhui University of Chinese Medicine, Hefei 230031, China
- Tropical Diseases Research Center, Nanjing Medical University, Wuxi 214064, China
| | - Yuyan Wang
- School of Public Health, Nanjing Medical University, Nanjing 211166, China;
| | - Yiyun Liu
- National Health Commission Key Laboratory of Parasitic Disease Control and Prevention, Jiangsu Provincial Key Laboratory on Parasite and Vector Control Technology, Jiangsu Institute of Parasitic Diseases, 117 Meiyuan Yangxiang, Wuxi 214064, China; (Q.X.)
- Tropical Diseases Research Center, Nanjing Medical University, Wuxi 214064, China
- School of Public Health, Nanjing Medical University, Nanjing 211166, China;
| | - Haiyong Hua
- National Health Commission Key Laboratory of Parasitic Disease Control and Prevention, Jiangsu Provincial Key Laboratory on Parasite and Vector Control Technology, Jiangsu Institute of Parasitic Diseases, 117 Meiyuan Yangxiang, Wuxi 214064, China; (Q.X.)
- Tropical Diseases Research Center, Nanjing Medical University, Wuxi 214064, China
| | - Xiangyu Zhou
- National Health Commission Key Laboratory of Parasitic Disease Control and Prevention, Jiangsu Provincial Key Laboratory on Parasite and Vector Control Technology, Jiangsu Institute of Parasitic Diseases, 117 Meiyuan Yangxiang, Wuxi 214064, China; (Q.X.)
- Tropical Diseases Research Center, Nanjing Medical University, Wuxi 214064, China
| | - Yongliang Xu
- National Health Commission Key Laboratory of Parasitic Disease Control and Prevention, Jiangsu Provincial Key Laboratory on Parasite and Vector Control Technology, Jiangsu Institute of Parasitic Diseases, 117 Meiyuan Yangxiang, Wuxi 214064, China; (Q.X.)
- Tropical Diseases Research Center, Nanjing Medical University, Wuxi 214064, China
| | - Ying Zhang
- National Health Commission Key Laboratory of Parasitic Disease Control and Prevention, Jiangsu Provincial Key Laboratory on Parasite and Vector Control Technology, Jiangsu Institute of Parasitic Diseases, 117 Meiyuan Yangxiang, Wuxi 214064, China; (Q.X.)
- Tropical Diseases Research Center, Nanjing Medical University, Wuxi 214064, China
| | - Chunrong Xiong
- National Health Commission Key Laboratory of Parasitic Disease Control and Prevention, Jiangsu Provincial Key Laboratory on Parasite and Vector Control Technology, Jiangsu Institute of Parasitic Diseases, 117 Meiyuan Yangxiang, Wuxi 214064, China; (Q.X.)
- Tropical Diseases Research Center, Nanjing Medical University, Wuxi 214064, China
| | - Xinjian Liu
- Department of Pathogen Biology, Key Laboratory of Antibody Techniques of National Health Commission, Nanjing Medical University, Nanjing 211166, China
| | - Kun Yang
- National Health Commission Key Laboratory of Parasitic Disease Control and Prevention, Jiangsu Provincial Key Laboratory on Parasite and Vector Control Technology, Jiangsu Institute of Parasitic Diseases, 117 Meiyuan Yangxiang, Wuxi 214064, China; (Q.X.)
- Tropical Diseases Research Center, Nanjing Medical University, Wuxi 214064, China
- School of Public Health, Nanjing Medical University, Nanjing 211166, China;
| | - Yuzheng Huang
- School of Public Health, Nanjing Medical University, Nanjing 211166, China;
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Hyperbilirubinemia Maintained by Chronic Supplementation of Unconjugated Bilirubin Improves the Clinical Course of Experimental Autoimmune Arthritis. Int J Mol Sci 2021; 22:ijms22168662. [PMID: 34445367 PMCID: PMC8395408 DOI: 10.3390/ijms22168662] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Revised: 08/06/2021] [Accepted: 08/06/2021] [Indexed: 11/23/2022] Open
Abstract
Rheumatoid arthritis (RA) is a chronic multisystem disease, therapy of which remains a challenge for basic research. The present work examined the effect of unconjugated bilirubin (UCB) administration in adjuvant-induced arthritis (AIA)—an experimental model, in which oxidative stress (OS), inflammation and inadequate immune response are often similar to RA. Male Lewis rats were randomized into groups: CO—control, AIA—untreated adjuvant-induced arthritis, AIA-BIL—adjuvant-induced arthritis administrated UCB, CO-BIL—control with administrated UCB. UCB was administered intraperitoneally 200 mg/kg of body weight daily from 14th day of the experiment, when clinical signs of the disease are fully manifested, to 28th day, the end of the experiment. AIA was induced by a single intradermal immunization at the base of the tail with suspension of Mycobacterium butyricum in incomplete Freund’s adjuvant. Clinical, hematologic, biochemical and histologic examinations were performed. UCB administration to animals with AIA lead to a significant decrease in hind paws volume, plasma levels of C-reactive protein (CRP) and ceruloplasmin, drop of leukocytes, lymphocytes, erythrocytes, hemoglobin and an increase in platelet count. UCB administration caused significantly lowered oxidative damage to DNA in arthritic animals, whereas in healthy controls it induced considerable oxidative damage to DNA. UCB administration also induced atrophy of the spleen and thymus in AIA and CO animals comparing to untreated animals. Histological signs of joint damage assessed by neutrophils infiltration and deposition of fibrin were significantly reduced by UCB administration. The effects of exogenously administered UCB to the animals with adjuvant-induced arthritis might be identified as therapeutic, in contrast to the effects of UCB administration in healthy animals rather classified as toxic.
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Yin H, Wang Z, Wang X, Lv X, Fan X, Yan M, Jia Y, Jiang L, Cao J, Liu Y. Inhibition of human UDP-glucuronosyltransferase enzyme by Dabrafenib: Implications for drug-drug interactions. Biomed Chromatogr 2021; 35:e5205. [PMID: 34192355 DOI: 10.1002/bmc.5205] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2021] [Revised: 05/30/2021] [Accepted: 06/19/2021] [Indexed: 12/14/2022]
Abstract
Dabrafenib is a novel small molecule tyrosine kinase inhibitor (TKI) which is used to treat metastatic melanoma. The aim of this research was to survey the effects of dabrafenib on human UDP-glucuronosyltransferases (UGTs) and to evaluate the risk of drug-drug interactions (DDIs). The formation rates for 4-methylumbelliferone (4-MU) glucuronide and trifluoperazine-glucuronide in 12 recombinant human UGT isoforms with or without dabrafenib were measured and HPLC was used to investigate the inhibitory effects of dabrafenib on UGTs. Inhibition kinetic studies were also conducted. In vitro-in vivo extrapolation approaches were further used to predict the risk of DDI potentials of dabrafenib via inhibition of UGTs. Our data indicated that dabrafenib had a broad inhibitory effect on 4-MU glucuronidation by inhibiting the activities of UGTs, especially on UGT1A1, UGT1A7, UGT1A8, and UGT1A9, and dabrafenib could increase the area under the curve of co-administered drugs. Dabrafenib is a strong inhibitor of several UGTs and the co-administration of dabrafenib with drugs primarily metabolized by UGT1A1, 1A7, 1A8 or 1A9 may induce potential DDIs.
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Affiliation(s)
- Hang Yin
- School of Life and Pharmaceutical Sciences, Dalian University of Technology, Panjin, China
| | - Zhe Wang
- School of Life and Pharmaceutical Sciences, Dalian University of Technology, Panjin, China
| | - Xiaoyu Wang
- School of Life and Pharmaceutical Sciences, Dalian University of Technology, Panjin, China
| | - Xin Lv
- School of Life and Pharmaceutical Sciences, Dalian University of Technology, Panjin, China
| | - Xiaoyu Fan
- School of Life and Pharmaceutical Sciences, Dalian University of Technology, Panjin, China
| | - Mingrui Yan
- School of Life and Pharmaceutical Sciences, Dalian University of Technology, Panjin, China
| | - Yanyan Jia
- School of Life and Pharmaceutical Sciences, Dalian University of Technology, Panjin, China
| | - Lili Jiang
- School of Life and Pharmaceutical Sciences, Dalian University of Technology, Panjin, China
| | - Jun Cao
- Department of Occupational and Environmental Health, Dalian Medical University, Dalian, China
| | - Yong Liu
- School of Life and Pharmaceutical Sciences, Dalian University of Technology, Panjin, China
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Zhu YD, Guan XQ, Chen J, Peng S, Finel M, Zhao YY, Wang RM, Bi HC, Lei M, Wang DD, Ge GB. Neobavaisoflavone Induces Bilirubin Metabolizing Enzyme UGT1A1 via PPARα and PPARγ. Front Pharmacol 2021; 11:628314. [PMID: 33628187 PMCID: PMC7897654 DOI: 10.3389/fphar.2020.628314] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Accepted: 12/24/2020] [Indexed: 12/30/2022] Open
Abstract
UDP-glucuronosyltransferase 1A1 (UGT1A1) is an essential enzyme in mammals that is responsible for detoxification and metabolic clearance of the endogenous toxin bilirubin and a variety of xenobiotics, including some crucial therapeutic drugs. Discovery of potent and safe UGT1A1 inducers will provide an alternative therapy for ameliorating hyperbilirubinaemia and drug-induced hepatoxicity. This study aims to find efficacious UGT1A1 inducer(s) from natural flavonoids, and to reveal the mechanism involved in up-regulating of this key conjugative enzyme by the flavonoid(s) with strong UGT1A1 induction activity. Among all the tested flavonoids, neobavaisoflavone (NBIF) displayed the most potent UGT1A1 induction activity, while its inductive effects were confirmed by both western blot and glucuronidation activity assays. A panel of nuclear receptor reporter assays demonstrated that NBIF activated PPARα and PPARγ in a dose-dependent manner. Meanwhile, we also found that NBIF could up-regulate the expression of PPARα and PPARγ in hepatic cells, suggesting that the induction of UGT1A1 by NBIF was mainly mediated by PPARs. In silico simulations showed that NBIF could stably bind on pocket II of PPARα and PPARγ. Collectively, our results demonstrated that NBIF is a natural inducer of UGT1A1, while this agent induced UGT1A1 mainly via activating and up-regulating PPARα and PPARγ. These findings suggested that NBIF can be used as a promising lead compound for the development of more efficacious UGT1A1 inducers to treat hyperbilirubinaemia and UGT1A1-associated drug toxicities.
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Affiliation(s)
- Ya-Di Zhu
- Trauma Emergency Center, The Seventh Affiliated People's Hospital of Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Xiao-Qing Guan
- Institute of Interdisciplinary Integrative Medicine Research, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Jing Chen
- Institute of Interdisciplinary Integrative Medicine Research, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Sheng Peng
- Trauma Emergency Center, The Seventh Affiliated People's Hospital of Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Moshe Finel
- Division of Pharmaceutical Chemistry and Technology, Faculty of Pharmacy, University of Helsinki, Helsinki, Finland
| | - Ying-Yuan Zhao
- School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, China
| | - Rui-Min Wang
- School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, China
| | - Hui-Chang Bi
- School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, China
| | - Ming Lei
- Trauma Emergency Center, The Seventh Affiliated People's Hospital of Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Dan-Dan Wang
- Institute of Interdisciplinary Integrative Medicine Research, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Guang-Bo Ge
- Institute of Interdisciplinary Integrative Medicine Research, Shanghai University of Traditional Chinese Medicine, Shanghai, China
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Zhu YD, Pang HL, Zhou QH, Qin ZF, Jin Q, Finel M, Wang YN, Qin WW, Lu Y, Wang DD, Ge GB. An ultra-sensitive and easy-to-use assay for sensing human UGT1A1 activities in biological systems. J Pharm Anal 2020; 10:263-270. [PMID: 32612873 PMCID: PMC7322753 DOI: 10.1016/j.jpha.2020.05.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Revised: 05/14/2020] [Accepted: 05/14/2020] [Indexed: 12/23/2022] Open
Abstract
The human UDP-glucuronosyltransferase 1A1 (UGT1A1), one of the most essential conjugative enzymes, is responsible for the metabolism and detoxification of bilirubin and other endogenous substances, as well as many different xenobiotic compounds. Deciphering UGT1A1 relevance to human diseases and characterizing the effects of small molecules on the activities of UGT1A1 requires reliable tools for probing the function of this key enzyme in complex biological matrices. Herein, an easy-to-use assay for highly-selective and sensitive monitoring of UGT1A1 activities in various biological matrices, using liquid chromatography with fluorescence detection (LC-FD), has been developed and validated. The newly developed LC-FD based assay has been confirmed in terms of sensitivity, specificity, precision, quantitative linear range and stability. One of its main advantages is lowering the limits of detection and quantification by about 100-fold in comparison to the previous assay that used the same probe substrate, enabling reliable quantification of lower amounts of active enzyme than any other method. The precision test demonstrated that both intra- and inter-day variations for this assay were less than 5.5%. Furthermore, the newly developed assay has also been successfully used to screen and characterize the regulatory effects of small molecules on the expression level of UGT1A1 in living cells. Overall, an easy-to-use LC-FD based assay has been developed for ultra-sensitive UGT1A1 activities measurements in various biological systems, providing an inexpensive and practical approach for exploring the role of UGT1A1 in human diseases, interactions with xenobiotics, and characterization modulatory effects of small molecules on this conjugative enzyme. An easy-to-use assay for sensing UGT1A1 activities has been developed, using LC-FD. The newly developed assay is fully validated. The LC-FD based assay is currently the most sensitive UGT1A1 activity assay.
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Affiliation(s)
- Ya-Di Zhu
- Institute of Interdisciplinary Integrative Medicine Research, Shanghai University of Traditional Chinese Medicine, Shanghai, 201203, China.,Jiangsu Key Laboratory for Pharmacology and Safety Evaluation of Chinese Materia Medica, School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing, 210023, China
| | - Hui-Lin Pang
- School of Life Science and Medicine, Dalian University of Technology, Panjin, 124221, China
| | - Qi-Hang Zhou
- Institute of Interdisciplinary Integrative Medicine Research, Shanghai University of Traditional Chinese Medicine, Shanghai, 201203, China
| | - Zi-Fei Qin
- Department of Pharmacy, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Qiang Jin
- Institute of Interdisciplinary Integrative Medicine Research, Shanghai University of Traditional Chinese Medicine, Shanghai, 201203, China
| | - Moshe Finel
- Division of Pharmaceutical Chemistry and Technology, Faculty of Pharmacy, University of Helsinki, 00014, Finland
| | - Yi-Nan Wang
- Institute of Interdisciplinary Integrative Medicine Research, Shanghai University of Traditional Chinese Medicine, Shanghai, 201203, China
| | - Wei-Wei Qin
- Department of Pharmacy, Huashan Hospital, Fudan University, Shanghai, China
| | - Yin Lu
- Jiangsu Key Laboratory for Pharmacology and Safety Evaluation of Chinese Materia Medica, School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing, 210023, China
| | - Dan-Dan Wang
- Institute of Interdisciplinary Integrative Medicine Research, Shanghai University of Traditional Chinese Medicine, Shanghai, 201203, China
| | - Guang-Bo Ge
- Institute of Interdisciplinary Integrative Medicine Research, Shanghai University of Traditional Chinese Medicine, Shanghai, 201203, China.,Jiangsu Key Laboratory for Pharmacology and Safety Evaluation of Chinese Materia Medica, School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing, 210023, China
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Lv X, Xia Y, Finel M, Wu J, Ge G, Yang L. Recent progress and challenges in screening and characterization of UGT1A1 inhibitors. Acta Pharm Sin B 2019; 9:258-278. [PMID: 30972276 PMCID: PMC6437557 DOI: 10.1016/j.apsb.2018.09.005] [Citation(s) in RCA: 58] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Revised: 08/16/2018] [Accepted: 08/27/2018] [Indexed: 02/07/2023] Open
Abstract
Uridine-diphosphate glucuronosyltransferase 1A1 (UGT1A1) is an important conjugative enzyme in mammals that is responsible for the conjugation and detoxification of both endogenous and xenobiotic compounds. Strong inhibition of UGT1A1 may trigger adverse drug/herb-drug interactions, or result in metabolic disorders of endobiotic metabolism. Therefore, both the US Food and Drug Administration (FDA) and the European Medicines Agency (EMA) have recommended assaying the inhibitory potential of drugs under development on the human UGT1A1 prior to approval. This review focuses on the significance, progress and challenges in discovery and characterization of UGT1A1 inhibitors. Recent advances in the development of UGT1A1 probes and their application for screening UGT1A1 inhibitors are summarized and discussed in this review for the first time. Furthermore, a long list of UGT1A1 inhibitors, including information on their inhibition potency, inhibition mode, and affinity, has been prepared and analyzed. Challenges and future directions in this field are highlighted in the final section. The information and knowledge that are presented in this review provide guidance for rational use of drugs/herbs in order to avoid the occurrence of adverse effects via UGT1A1 inhibition, as well as presenting methods for rapid screening and characterization of UGT1A1 inhibitors and for facilitating investigations on UGT1A1-ligand interactions.
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Bauerova K, Drafi F, Kuncirova V, Ponist S, Mihalova D, Babal P, Sykora T. Hyperbilirubinemia decreases physiological markers in adjuvant-induced arthritis. Physiol Res 2015; 64:S459-66. [PMID: 26681075 DOI: 10.33549/physiolres.933202] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
There is evidence that a higher serum level of bilirubin (BIL) may be a protective factor for autoimmune diseases. We examined the effect of BIL supplementation in adjuvant-induced arthritis (AIA) where oxidative stress, inflammation and inadequate immune response are present. Male Lewis rats were randomized into groups: CO - control, AIA - untreated adjuvant-induced arthritis, AIA-BIL - adjuvant-induced arthritis administrated BIL (200 mg/kg b.w. daily i.p. during 14 days). Change of hind paw volume in the AIA-BIL group in comparison to the AIA group was significantly decreased after BIL administration. In CO and AIA groups we found almost untraceable levels of BIL. In the AIA-BIL group hyperbilirubinemia was observed. BIL administration significantly decreased plasma levels of C-reactive protein and ceruloplasmin in the AIA-BIL group in comparison to the AIA group. The values of white and red blood cells, hemoglobin and hematocrit were significantly decreased in AIA-BIL after BIL supplementation. Organs like spleen and thymus had a lower weight in AIA-BIL than in AIA. Histological findings showed decreased or even absent damage in hind paw joint of AIA-BIL animals. We observed an immunomodulatory effect of BIL on AIA development, which may also have a novel pharmacological impact.
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Affiliation(s)
- K Bauerova
- Institute of Experimental Pharmacology and Toxicology, Slovak Academy of Sciences, Bratislava, Slovak Republic.
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Abstract
Total serum bilirubin is associated with several clinical outcomes, including cardiovascular disease, diabetes and drug metabolism. We conducted a genome-wide association study in 619 healthy unrelated African Americans in an attempt to replicate reported findings in Europeans and Asians and to identify novel loci influencing total serum bilirubin levels. We analyzed a dense panel of over two million genotyped and imputed SNPs in additive genetic models adjusting for age, sex, and the first two significant principal components from the sample covariance matrix of genotypes. Thirty-nine SNPs spanning a 78 kb region within the UGT1A1 displayed P-values <5 × 10−8. The lowest P-value was 1.7 × 10−22 for SNP rs887829. None of SNPs in the UGT1A1 remained statistically significant in conditional association analyses that adjusted for rs887829. In addition, SNP rs10929302 located in phenobarbital response enhancer module was significantly associated with bilirubin level with a P-value of 1.37 × 10−11; this enhancer module is believed to have a critical role in phenobarbital treatment of hyperbilirubinemia. Interestingly, the lead SNP, rs887829, is in strong linkage disequilibrium (LD) (r2≥0.74) with rs10929302. Taking advantage of the lower LD and shorter haplotypes in African-ancestry populations, we identified rs887829 as a more refined proxy for the causative variant influencing bilirubin levels. Also, we replicated the reported association between variants in SEMA3C and bilirubin levels. In summary, UGT1A1 is a major locus influencing bilirubin levels and the results of this study promise to contribute to understanding of the etiology and treatment of hyperbilirubinaemia in African-ancestry populations.
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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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Abstract
Despite a century of research, several clinically relevant areas of bilirubin biochemistry remain controversial, poorly understood, or unrecognized. These include: (i) The structure and molecularity of bilirubin under physiological environments such as membranes, brain tissue and when bound to proteins. Related to this is the large number of structurally different bilirubin species that may occur in blood under pathological conditions and their potential effects on measurements of bilirubin and free bilirubin. (ii) The mechanism of phototherapy, the neurotoxicity of the photoisomers produced and their influence on measurements of bilirubin and free bilirubin. (iii) The role of membrane transporters in the passage of unconjugated bilirubin across the placenta, intestine, vascular epithelium, blood-brain barrier, and into the liver. (iv) Biochemical mechanisms of bilirubin toxicity, pharmacologic prevention of kernicterus, the contribution of bilirubin to antioxidant defenses, and the practical value of free bilirubin measurements for identifying infants at most risk of kernicterus.
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Ozkan H, Oren H, Tatli M, Ateş H, Kumral A, Duman N. Erythroid apoptosis in idiopathic neonatal jaundice. Pediatrics 2008; 121:e1348-51. [PMID: 18426853 DOI: 10.1542/peds.2007-2215] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
OBJECTIVES The objectives of this study were to evaluate the contribution of erythroid apoptosis to neonatal idiopathic pathologic jaundice and to determine whether a measurement of the erythroid apoptosis value at birth could predict the development of hyperbilirubinemia during the first 15 days of life. PATIENTS AND METHODS Three groups were defined: group 1 (n = 101), healthy newborns whose erythroid apoptosis value and serum total bilirubin levels were detected from birth to day 15; group 2 (n = 24), newborns who were hospitalized for jaundice (serum total bilirubin level: > 12.9 mg/dL) without any identifiable pathologic cause; and group 3 (control group, n = 24), healthy newborns whose serum total bilirubin levels were < or = 12.9 mg/dL. Erythroid apoptosis value was assessed by flow cytometry using an annexin-V fluorescein isothiocyanate kit. RESULTS In group 1, there was no correlation between the erythroid apoptosis value and serum total bilirubin levels obtained at birth and at the fourth and 15th days of life; the erythrocyte apoptosis value obtained at birth was not significantly different between the neonates whose serum total bilirubin levels were > 12.9 and < or = 12.9 mg/dL and who had prolonged and nonprolonged jaundice during follow-up. The erythroid apoptosis value differed significantly between the newborns in groups 2 and 3. There was no significant correlation between the erythroid apoptosis value and serum total bilirubin levels of the infants in groups 2 and 3. CONCLUSIONS The erythroid apoptosis value obtained at birth could not predict the development of hyperbilirubinemia in neonates, but it was increased significantly in jaundiced neonates whose serum total bilirubin levels were > 12.9 mg/dL. In these infants, increase in the erythroid apoptosis value may be a result of the toxic effect of bilirubin or of a protective mechanism of neonates to increase heme turnover and bilirubin production to diminish oxidative stress.
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Affiliation(s)
- Hasan Ozkan
- Dokuz Eylül University Faculty of Medicine, Department of Pediatric Neonatology, 35340 Balcova, Izmir, Turkey
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