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Gao L, Zhang W, Zhang L, Gromova B, Chen G, Csizmadia E, Cagle C, Nastasio S, Ma Y, Bonder A, Patwardhan V, Robson SC, Jiang S, Longhi MS. Silencing of aryl hydrocarbon receptor repressor restrains Th17 cell immunity in autoimmune hepatitis. J Autoimmun 2024; 143:103162. [PMID: 38142533 PMCID: PMC10981568 DOI: 10.1016/j.jaut.2023.103162] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2023] [Revised: 11/20/2023] [Accepted: 12/12/2023] [Indexed: 12/26/2023]
Abstract
Th17-cells play a key role in the pathogenesis of autoimmune hepatitis (AIH). Dysregulation of Th17-cells in AIH is linked to defective response to aryl-hydrocarbon-receptor (AhR) activation. AhR modulates adaptive immunity and is regulated by aryl-hydrocarbon-receptor-repressor (AHRR), which inhibits AhR transcriptional activity. In this study, we investigated whether defective Th17-cell response to AhR derives from aberrant AHRR regulation in AIH. Th17-cells, obtained from the peripheral blood of AIH patients (n = 30) and healthy controls (n = 30) were exposed to AhR endogenous ligands, and their response assessed in the absence or presence of AHRR silencing. Therapeutic effects of AHRR blockade were tested in a model of Concanavalin-A (Con-A)-induced liver injury in humanized mice. AHRR was markedly upregulated in AIH Th17-cells, following exposure to l-kynurenine, an AhR endogenous ligand. In patients, silencing of AHRR boosted Th17-cell response to l-kynurenine, as reflected by increased levels of CYP1A1, the main gene controlled by AhR; and decreased IL17A expression. Blockade of AHRR limited the differentiation of naïve CD4-cells into Th17 lymphocytes; and modulated Th17-cell metabolic profile by increasing the levels of uridine via ATP depletion or pyrimidine salvage. Treatment with 2'-deoxy-2'-fluoro-d-arabinonucleic acid (FANA) oligonucleotides to silence human AHRR in vivo, reduced ALT levels, attenuated lymphocyte infiltration on histology, and heightened frequencies of regulatory immune subsets in NOD/scid/gamma mice, reconstituted with human CD4 cells, and exposed to Con-A. In conclusion, blockade of AHRR in AIH restores Th17-cell response to AHR, and limits Th17-cell differentiation through generation of uridine. In vivo, silencing of AHRR attenuates liver damage in NOD/scid/gamma mice. Blockade of AHRR might therefore represent a novel therapeutic strategy to modulate effector Th17-cell immunity and restore homeostasis in AIH.
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Affiliation(s)
- Li Gao
- Department of Anesthesia, Critical Care & Pain Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA; Department of Endocrinology and Metabolism, The First Affiliated Hospital of Shandong First Medical University & Shandong Provincial Qianfoshan Hospital, Jinan, Shandong, China.
| | - Wei Zhang
- Department of Anesthesia, Critical Care & Pain Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA; Department of Endocrinology and Metabolism, The First Affiliated Hospital of Shandong First Medical University & Shandong Provincial Qianfoshan Hospital, Jinan, Shandong, China.
| | - Lina Zhang
- Department of Anesthesia, Critical Care & Pain Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA; School of Arts and Sciences, Tufts University, Medford, MA, USA.
| | - Barbora Gromova
- Department of Anesthesia, Critical Care & Pain Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA; Institute of Molecular Biomedicine, Faculty of Medicine, Comenius University, Bratislava, Slovakia.
| | - Guanqing Chen
- Department of Anesthesia, Critical Care & Pain Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA.
| | - Eva Csizmadia
- Department of Anesthesia, Critical Care & Pain Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA.
| | - Cortney Cagle
- Department of Anesthesia, Critical Care & Pain Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA.
| | - Silvia Nastasio
- Department of Anesthesia, Critical Care & Pain Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA; Division of Gastroenterology, Hepatology and Nutrition, Boston Children's Hospital, Boston, MA, USA.
| | - Yun Ma
- Institute of Liver Studies, School of Immunology & Microbial Sciences, Faculty of Life Sciences & Medicine, King's College London, London, UK.
| | - Alan Bonder
- Division of Gastroenterology, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA.
| | - Vilas Patwardhan
- Division of Gastroenterology, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA.
| | - Simon C Robson
- Department of Anesthesia, Critical Care & Pain Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA; Division of Gastroenterology, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA.
| | - Sizun Jiang
- Center for Virology and Vaccine Research, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA.
| | - Maria Serena Longhi
- Department of Anesthesia, Critical Care & Pain Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA.
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Occurrence of Recurrent Aphthous Stomatitis (RAS) as a Rare Oral Manifestation in a Patient with Gilbert's Syndrome. Case Rep Dent 2021; 2021:6648729. [PMID: 33953989 PMCID: PMC8068538 DOI: 10.1155/2021/6648729] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2020] [Revised: 04/01/2021] [Accepted: 04/07/2021] [Indexed: 12/15/2022] Open
Abstract
Recurrent aphthous stomatitis is an ulcerative disease of the oral cavity and can occur in isolation or as a manifestation of many systemic diseases. It is a quite common entity and may hence often be overlooked as an isolated lesion. Gilbert's syndrome is a genetic disorder where a deficiency of an enzyme associated with the conjugation of bilirubin results in unconjugated hyperbilirubinemia. The disease is generally asymptomatic and is aggravated by certain trigger factors. No associated oral manifestations are known. In this case report, we discuss the concomitant presence of recurrent aphthous stomatitis in a patient of Gilbert's syndrome. The presence of such recurrent stomatitis may represent as an oral manifestation of Gilbert's syndrome. Early identification of these entities may improve the overall quality of life of the patient.
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Sahara K, Tsilimigras DI, Toyoda J, Miyake K, Ethun CG, Maithel SK, Abbott DE, Poultsides GA, Hatzaras I, Fields RC, Weiss M, Scoggins C, Isom CA, Idrees K, Shen P, Yabushita Y, Matsuyama R, Endo I, Pawlik TM. Defining the Risk of Early Recurrence Following Curative-Intent Resection for Distal Cholangiocarcinoma. Ann Surg Oncol 2021; 28:4205-4213. [PMID: 33709171 DOI: 10.1245/s10434-021-09811-4] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2020] [Accepted: 02/19/2021] [Indexed: 01/27/2023]
Abstract
BACKGROUND Although multidisciplinary treatments including the use of adjuvant therapy (AT) have been adopted for biliary tract cancers, patients with distal cholangiocarcinoma (DCC) can still experience recurrence. We sought to characterize the incidence and predictors of early recurrence (ER) that occurred within 12 months following surgery for DCC. PATIENTS AND METHODS Patients who underwent resection for DCC between 2000 and 2015 were identified from the US multi-institutional database. Cox regression analysis was used to identify clinicopathological factors to develop an ER risk score, and the predictive model was validated in an external dataset. RESULTS Among 245 patients included in the analysis, 67 patients (27.3%) developed ER. No difference was noted in ER rates between patients who did and did not receive AT (28.7% vs. 25.0%, p = 0.55). Multivariable analysis revealed that neutrophil-to-lymphocyte ratio (NLR), peak total bilirubin (T-Bil), major vascular resection (MVR), lymphovascular invasion, and R1 surgical margin status were associated with a higher ER risk. A DIstal Cholangiocarcinoma Early Recurrence Score was developed according to each factor available prior to surgery [NLR > 9.0 (2 points); peak T-bil > 1.5 mg/dL (1 points); MVR (2 points)]. Cumulative ER rates incrementally increased among patients who were low (0 points; 10.6%), intermediate (1-2 points; 26.8%), or high (3-5 points; 57.6%) risk (p < 0.001) in the training dataset, as well as in the validation dataset [low (0 points); 3.4%, intermediate (1-2 points); 32.7%, or high risk (3-5 points); 55.6% (p < 0.001)]. CONCLUSIONS Among patients undergoing resection for DCC, 1 in 4 patients experienced an ER. Alternative treatment strategies such as neoadjuvant chemotherapy may be considered especially among individuals deemed to be at high risk for ER.
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Affiliation(s)
- Kota Sahara
- Department of Gastroenterological Surgery, Yokohama City University School of Medicine, Yokohama, Japan.,Division of Surgical Oncology, Health Services Management and Policy, Department of Surgery, The Urban Meyer III and Shelley Meyer Chair for Cancer Research, The Ohio State University Wexner Medical Center and James Comprehensive Cancer Center, Columbus, OH, USA
| | - Diamantis I Tsilimigras
- Division of Surgical Oncology, Health Services Management and Policy, Department of Surgery, The Urban Meyer III and Shelley Meyer Chair for Cancer Research, The Ohio State University Wexner Medical Center and James Comprehensive Cancer Center, Columbus, OH, USA
| | - Junya Toyoda
- Department of Gastroenterological Surgery, Yokohama City University School of Medicine, Yokohama, Japan
| | - Kentaro Miyake
- Department of Gastroenterological Surgery, Yokohama City University School of Medicine, Yokohama, Japan
| | - Cecilia G Ethun
- Division of Surgical Oncology, Department of Surgery, Winship Cancer Institute, Emory University, Atlanta, GA, USA
| | - Shishir K Maithel
- Division of Surgical Oncology, Department of Surgery, Winship Cancer Institute, Emory University, Atlanta, GA, USA
| | - Daniel E Abbott
- Department of Surgery, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA
| | - George A Poultsides
- Department of Surgery, Stanford University Medical Center, Stanford, CA, USA
| | | | - Ryan C Fields
- Department of Surgery, Washington University School of Medicine, St Louis, MO, USA
| | - Matthew Weiss
- Department of Surgery, Johns Hopkins Hospital, Baltimore, MD, USA
| | - Charles Scoggins
- Division of Surgical Oncology, Department of Surgery, University of Louisville, Louisville, KY, USA
| | - Chelsea A Isom
- Division of Surgical Oncology, Department of Surgery, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Kamran Idrees
- Division of Surgical Oncology, Department of Surgery, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Perry Shen
- Department of Surgery, Wake Forest University, Winston-Salem, NC, USA
| | - Yasuhiro Yabushita
- Department of Gastroenterological Surgery, Yokohama City University School of Medicine, Yokohama, Japan
| | - Ryusei Matsuyama
- Department of Gastroenterological Surgery, Yokohama City University School of Medicine, Yokohama, Japan
| | - Itaru Endo
- Department of Gastroenterological Surgery, Yokohama City University School of Medicine, Yokohama, Japan
| | - Timothy M Pawlik
- Division of Surgical Oncology, Health Services Management and Policy, Department of Surgery, The Urban Meyer III and Shelley Meyer Chair for Cancer Research, The Ohio State University Wexner Medical Center and James Comprehensive Cancer Center, Columbus, OH, USA.
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Vuerich M, Harshe R, Frank LA, Mukherjee S, Gromova B, Csizmadia E, Nasser IAM, Ma Y, Bonder A, Patwardhan V, Robson SC, Longhi MS. Altered aryl-hydrocarbon-receptor signalling affects regulatory and effector cell immunity in autoimmune hepatitis. J Hepatol 2021; 74:48-57. [PMID: 32663496 PMCID: PMC7749856 DOI: 10.1016/j.jhep.2020.06.044] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/02/2020] [Revised: 06/15/2020] [Accepted: 06/24/2020] [Indexed: 12/19/2022]
Abstract
BACKGROUND & AIMS In autoimmune hepatitis (AIH), the imbalance between regulatory T cells (Tregs) and T-helper type 17 (Th17) cells has been linked to low levels of CD39, an ectoenzyme that hydrolyses ATP, ultimately generating immunosuppressive adenosine. Upregulation of CD39 results from activation of aryl hydrocarbon receptor (AHR), which mediates toxin responses to modulate T-cell immunity. In this study, we investigated whether altered AHR signalling underlies defective CD39 expression and function in AIH Tregs and Th17 cells, therefore contributing to regulatory/effector cell imbalance. METHODS Tregs and Th17 cells, obtained from the peripheral blood of 49 patients with AIH and 21 healthy individuals (HI), were tested for response to endogenous and exogenous AHR ligands. RESULTS When compared to those of HI, AIH-derived Tregs and Th17 cells displayed impaired responses to AHR activation, reflected by impaired upregulation of CD39, delayed increase in ectoenzymatic activity, and defective Treg suppressive function. These impairments resulted, at least in part, from heightened levels of AHRR and Erα in Tregs and high HIF-1α in Th17 cells, and were reverted upon molecular blockade. Importantly, in AIH-derived Tregs, the binding affinity of AHR was higher for Erα than ARNT. CONCLUSIONS In AIH, high levels of AHRR and HIF-1α inhibit AHR signalling in Tregs and Th17 cells. AHR non-canonical binding to Erα further amplifies the lack of effective CD39 upregulation. Blockade of these inhibitory and/or non-canonical activation pathways represents a potential therapeutic approach to restore CD39 and immunohomeostasis in AIH. LAY SUMMARY In patients with autoimmune hepatitis, the imbalance between regulatory T cells and T helper type-17 cells is linked to dysfunction of the aryl hydrocarbon receptor pathway, resulting from aberrant inhibition or non-canonical activation. These alterations impair Treg- and Th17 cell-induced upregulation of CD39, an ectoenzyme key to immunoregulation. Blockade of excessive inhibition or non-canonical activation of the aryl hydrocarbon receptor pathway might represent a novel therapeutic strategy to control inflammation while restoring immune balance in autoimmune hepatitis.
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Affiliation(s)
- Marta Vuerich
- Department of Anesthesia, Critical Care & Pain Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, 330 Brookline Avenue, Boston, MA 02215, USA
| | - Rasika Harshe
- Department of Anesthesia, Critical Care & Pain Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, 330 Brookline Avenue, Boston, MA 02215, USA
| | - Luiza Abrahão Frank
- Department of Anesthesia, Critical Care & Pain Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, 330 Brookline Avenue, Boston, MA 02215, USA
| | - Samiran Mukherjee
- Department of Anesthesia, Critical Care & Pain Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, 330 Brookline Avenue, Boston, MA 02215, USA
| | - Barbora Gromova
- Department of Anesthesia, Critical Care & Pain Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, 330 Brookline Avenue, Boston, MA 02215, USA,Institute of Molecular Biomedicine, Faculty of Medicine, Comenius University, Bratislava, Slovakia
| | - Eva Csizmadia
- Department of Anesthesia, Critical Care & Pain Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, 330 Brookline Avenue, Boston, MA 02215, USA
| | - Imad AM Nasser
- Department of Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, 330 Brookline Avenue, Boston, MA 02215, USA
| | - Yun Ma
- Institute of Liver Studies, Department of Inflammation Biology, School of Immunology & Microbial Sciences, Faculty of Liver Sciences and Medicine, King’s College London, London, United Kingdom
| | - Alan Bonder
- Division of Gastroenterology, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, 330 Brookline Avenue, Boston, MA 02215, USA
| | - Vilas Patwardhan
- Division of Gastroenterology, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, 330 Brookline Avenue, Boston, MA 02215, USA
| | - Simon C. Robson
- Department of Anesthesia, Critical Care & Pain Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, 330 Brookline Avenue, Boston, MA 02215, USA,Division of Gastroenterology, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, 330 Brookline Avenue, Boston, MA 02215, USA
| | - Maria Serena Longhi
- Department of Anesthesia, Critical Care and Pain Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA.
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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: 40] [Impact Index Per Article: 10.0] [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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Jangi S, Otterbein L, Robson S. The molecular basis for the immunomodulatory activities of unconjugated bilirubin. Int J Biochem Cell Biol 2013; 45:2843-51. [PMID: 24144577 DOI: 10.1016/j.biocel.2013.09.014] [Citation(s) in RCA: 97] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2013] [Revised: 09/24/2013] [Accepted: 09/29/2013] [Indexed: 01/03/2023]
Abstract
Nearly a century ago, jaundiced patients were observed to have surprising and spontaneous remissions from incurable immunologic diseases including rheumatoid arthritis, allergy, and asthma. The mystery of why this phenomenon occurred remains unresolved to this day. Bilirubin has traditionally been considered an excretory product resulting from heme metabolism with little benefit to human physiology. In the past few decades, however, the salutary role of this byproduct as a potent antioxidant has been repeatedly noted. Most recently, the molecule has been found to possess immunomodulatory properties that rival its redox capacity, possibly explaining its ability to suppress inflammation. In this review, we specifically examine unconjugated bilirubin (UCB) as an immunomodulator and explore the molecular basis for its immunosuppressive effects.
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Affiliation(s)
- Sushrut Jangi
- Beth Israel Deaconess Medical Center, United States; Harvard Medical School, United States.
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7
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Khan NM, Poduval TB. Bilirubin augments radiation injury and leads to increased infection and mortality in mice: molecular mechanisms. Free Radic Biol Med 2012; 53:1152-69. [PMID: 22819982 DOI: 10.1016/j.freeradbiomed.2012.07.007] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/01/2012] [Accepted: 07/08/2012] [Indexed: 01/15/2023]
Abstract
Our earlier results demonstrated that clinically relevant concentrations of unconjugated bilirubin (UCB) possessed immunotoxic effects. Whole-body irradiation (WBI) with 1 to 6 Gy leads to acute radiation syndrome, immunosuppression, and makes the host susceptible to infection. Since hyperbilirubinemia has been shown to be associated with several types of cancer, the present studies were undertaken to evaluate the radiomodifying effects of UCB in radiation-exposed mice having elevated levels of UCB. Pretreatment of splenic lymphocytes with UCB (1-50 μM at UCB/BSA ratio <1) augmented radiation-induced DNA strand breaks, MMP loss, calcium release, and apoptosis. Combination treatment of mice with UCB (50mg/kg bw) followed by WBI (2 Gy) 0.5h later, resulted in significantly increased splenic atrophy, bone marrow aplasia, decreased counts of peritoneal exudate cells, and different splenocyte subsets such as CD3+ T, CD4+ T, CD8+ T, CD19+ B, and CD14+ macrophages as compared to either UCB or WBI treatment. Hematological studies showed that WBI-induced lymphopenia, thrombocytopenia, and neutropenia were further aggravated in the combination treatment group. UCB pretreatment of mice potentiated WBI-induced apoptosis and decreased WBI-induced loss of functional response of various immune cells leading to augmentation of immunosuppression and infection susceptibility caused by WBI. In an acute bacterial peritonitis model, UCB pretreatment of mice significantly increased WBI-induced proinflammatory cytokines, nitric oxide, and peritoneal bacterial load resulting in increased infection and death. Studies using the pharmacological inhibitor of p38MAPK demonstrated the involvement of p38MAPK activation in the inflammatory cascade of peritonitis. These findings should prove useful in understanding the potential risk to hyperbilirubinemic patients during radiotherapy and victims of acute radiation exposure in the course of radiation accidents.
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Affiliation(s)
- Nazir M Khan
- Immunology and Hyperthermia Section, Radiation Biology and Health Sciences Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085, India.
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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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Silva SL, Vaz AR, Barateiro A, Falcão AS, Fernandes A, Brito MA, Silva RF, Brites D. Features of bilirubin-induced reactive microglia: From phagocytosis to inflammation. Neurobiol Dis 2010; 40:663-75. [DOI: 10.1016/j.nbd.2010.08.010] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2010] [Revised: 07/26/2010] [Accepted: 08/11/2010] [Indexed: 01/05/2023] Open
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Vítek L, Schwertner HA. The Heme Catabolic Pathway and its Protective Effects on Oxidative Stress‐Mediated Diseases. Adv Clin Chem 2007; 43:1-57. [PMID: 17249379 DOI: 10.1016/s0065-2423(06)43001-8] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Bilirubin, the principal bile pigment, is the end product of heme catabolism. For many years, bilirubin was thought to have no physiological function other than that of a waste product of heme catabolism--useless at best and toxic at worst. Although hyperbilirubinemia in neonates has been shown to be neurotoxic, studies performed during the past decade have found that bilirubin has a number of new and interesting biochemical and biological properties. In addition, there is now a strong body of evidence suggesting that bilirubin may have a beneficial role in preventing oxidative changes in a number of diseases including atherosclerosis and cancer, as well as a number of inflammatory, autoimmune, and degenerative diseases. The results also suggest that activation of the heme oxygenase and heme catabolic pathway may have beneficiary effects on disease prevention either through the action of bilirubin or in conjunction with bilirubin. If so, it may be possible to therapeutically induce heme oxygenase, increase bilirubin concentrations, and lower the risk of oxidative stress-related diseases.
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Affiliation(s)
- Libor Vítek
- Fourth Department of Internal Medicine, Institute of Clinical Biochemistry, Laboratory Diagnostics, Charles University of Prague, U Nemocnice 2, Praha 2, 128 08 Prague, Czech Republic
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Alexandra Brito M, Silva RFM, Brites D. Bilirubin toxicity to human erythrocytes: a review. Clin Chim Acta 2006; 374:46-56. [PMID: 16887110 DOI: 10.1016/j.cca.2006.06.012] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2006] [Revised: 06/05/2006] [Accepted: 06/12/2006] [Indexed: 11/17/2022]
Abstract
Neonatal jaundice, a physiologic condition reflecting the interplay between developmentally modulated changes in bilirubin production and metabolism, affects virtually all newborn infants. Usually, it is an entirely benign process that is resolved at the end of the first week of life without treatment or sequelae. However, in a small percentage of neonates, unconjugated hyperbilirubinemia can pose a neurotoxic risk especially in the presence of aggravating conditions such as a diminished albumin binding capacity and/or affinity, acidosis, displacing drugs and prematurity. Although neuronal cells are considered the main target for unconjugated bilirubin (UCB) toxicity, circulating cells are also affected during neonatal hyperbilirubinemia. Moreover, the UCB ability to cause hemolysis shall further aggravate neonatal jaundice through a vicious circle. In this review, we summarize the most relevant data obtained by our group regarding UCB toxicity and the role of some risk factors for kernicterus. In order to improve the risk assessment of neurotoxicity it is essential to understand the underlying mechanisms of UCB pathophysiology.
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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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Liu Y, Liu J, Tetzlaff W, Paty DW, Cynader MS. Biliverdin reductase, a major physiologic cytoprotectant, suppresses experimental autoimmune encephalomyelitis. Free Radic Biol Med 2006; 40:960-7. [PMID: 16540391 DOI: 10.1016/j.freeradbiomed.2005.07.021] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/11/2005] [Revised: 07/16/2005] [Accepted: 07/27/2005] [Indexed: 10/25/2022]
Abstract
Oxidative stress plays an important role in the pathogenesis of multiple sclerosis and its animal model, experimental autoimmune encephalomyelitis (EAE). Bilirubin is regarded today as a potent antioxidant. Recent studies show that the potent antioxidant actions of bilirubin reflect an amplification mechanism whereby biliverdin reductase (BVR) physiologically regenerates bilirubin in a catalytic cycle. We hypothesized that BVR might prove to be a new effective target for the treatment of free radical-mediated diseases. In this study, we demonstrated that treatment with BVR ameliorated both clinical and pathological signs of EAE more efficiently than treatments with traditional antioxidant enzymes. In vitro, interference with cellular BVR activity by siRNA elicited greater increases in reactive oxygen species and cell death than interference with the activities of other antioxidant enzymes. Further studies showed that BVR surpasses other enzymes by the multifactorial functions of its only end product, bilirubin, including anti-complement activity, and an activity that inhibits antibody-dependent cell-mediated cytotoxicity of lymphocytes. Since BVR regenerates bilirubin in a redox cycle without significantly increasing the concentration of bilirubin, our results suggest that BVR may represent a novel strategy for the treatment of multiple sclerosis and other oxidative stress-mediated diseases.
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Affiliation(s)
- Yingru Liu
- Brain Research Center, University of British Columbia, 2211 Wesbrook Mall, Vancouver, BC, Canada V6T 2B5.
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Fernandes A, Silva RFM, Falcão AS, Brito MA, Brites D. Cytokine production, glutamate release and cell death in rat cultured astrocytes treated with unconjugated bilirubin and LPS. J Neuroimmunol 2004; 153:64-75. [PMID: 15265664 DOI: 10.1016/j.jneuroim.2004.04.007] [Citation(s) in RCA: 86] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2004] [Revised: 04/21/2004] [Accepted: 04/21/2004] [Indexed: 11/19/2022]
Abstract
In hyperbilirubinemic newborns, sepsis is considered a risk factor for kernicterus. Evidence shows that injury to astrocytes triggers cytokine release. We examined the effects of unconjugated bilirubin (UCB) alone, or in combination with LPS, on the release of glutamate and cytokines from astrocytes in conditions inducing less than 10% of cell death. UCB leads to an increase of extracellular glutamate and highly enhances the release of TNF-alpha and IL-1beta, while inhibiting the production of IL-6. LPS potentiates immunostimulatory properties of UCB. These results point out the role of cytokines and provide a basis for the significance of sepsis in UCB encephalopathy.
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Affiliation(s)
- Adelaide Fernandes
- Centro de Patogénese Molecular (UBMBE), Faculdade de Farmácia, University of Lisbon, Av. Forças Armadas, 1600-083 Lisbon, Portugal
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Meloni-Bruneri LH, Picina C, Burger E, Friedrich M, Sanazzaro CA, Campa A. Changes in plasmatic biochemical parameters during experimental murine paracoccidioidomycosis. JOURNAL OF MEDICAL AND VETERINARY MYCOLOGY : BI-MONTHLY PUBLICATION OF THE INTERNATIONAL SOCIETY FOR HUMAN AND ANIMAL MYCOLOGY 1997; 35:237-41. [PMID: 9292419 DOI: 10.1080/02681219780001211] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Determinations of plasma cholesterol, HDL-cholesterol, triglycerides, total proteins, bilirubin, aspartate transaminases (AST), glucose, iron and total iron binding capacity were evaluated after 15 and 90 days of intraperitoneal infection with 5 x 10(6) virulent yeasts of Paracoccidioides brasiliensis Pb 18 isolate in resistant (A/J) and susceptible (B10.A) mice. Significant differences between control and infected groups were seen: an increase of triglycerides and total proteins for both strains, a decrease of glucose and HDL-cholesterol in B10.A mice and of iron in both strains, while AST, bilirubin and TIBC increased only in B10.A mice. While glucose, AST, bilirubin and TIBC were strongly modified in susceptible mice, no differences were seen in the resistant infected group, thus confirming the usefulness of biochemical parameters as an index of infection severity, as well as of recovery.
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Affiliation(s)
- L H Meloni-Bruneri
- Departamento de Análises Clínicas e Toxicológicas, Faculdade de Ciências Farmacêuticas, Hospital Universitário, Universidade de São Paulo, Brasil
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Abstract
The neurotoxic effects of bilirubin may involve modulation of neuronal protein phosphorylation systems. Using in vitro phosphorylation assays and a variety of protein substrates and purified protein kinases, we have studied the mechanism of bilirubin-induced inhibition of protein phosphorylation. Bilirubin was found to inhibit cAMP-dependent, cGMP-dependent, Ca(2+)- calmodulin-dependent, and Ca(2+)-phospholipid-dependent protein kinases, irrespective of substrate properties. Fifty percent inhibition occurred at bilirubin concentrations varying from 20 to 125 microM. Kinetic analysis, using the isolated catalytic subunit of cAMP-dependent kinase and a synthetic peptide substrate derived from the protein phospholemman, indicated that bilirubin (50 microM) decreased the apparent Vmax of the reaction, irrespective of whether ATP or peptide levels were varied, without significantly altering the apparent K(m) value. Thus our results indicate that bilirubin can inhibit catalytic domain(s) of protein kinases by apparent noncompetitive mechanism(s), presumably by interacting with noncatalytic domains on the enzyme. Given the key role of protein phosphorylation in cellular regulation, the widespread inhibitory effect of bilirubin on protein kinases may contribute to bilirubin neurotoxicity.
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Affiliation(s)
- T W Hansen
- Neurochemical Laboratory, University of Oslo, Norway
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