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Barata IS, Rueff J, Kranendonk M, Esteves F. Pleiotropy of Progesterone Receptor Membrane Component 1 in Modulation of Cytochrome P450 Activity. J Xenobiot 2024; 14:575-603. [PMID: 38804287 PMCID: PMC11130977 DOI: 10.3390/jox14020034] [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: 03/15/2024] [Revised: 04/26/2024] [Accepted: 04/29/2024] [Indexed: 05/29/2024] Open
Abstract
Progesterone receptor membrane component 1 (PGRMC1) is one of few proteins that have been recently described as direct modulators of the activity of human cytochrome P450 enzymes (CYP)s. These enzymes form a superfamily of membrane-bound hemoproteins that metabolize a wide variety of physiological, dietary, environmental, and pharmacological compounds. Modulation of CYP activity impacts the detoxification of xenobiotics as well as endogenous pathways such as steroid and fatty acid metabolism, thus playing a central role in homeostasis. This review is focused on nine main topics that include the most relevant aspects of past and current PGRMC1 research, focusing on its role in CYP-mediated drug metabolism. Firstly, a general overview of the main aspects of xenobiotic metabolism is presented (I), followed by an overview of the role of the CYP enzymatic complex (IIa), a section on human disorders associated with defects in CYP enzyme complex activity (IIb), and a brief account of cytochrome b5 (cyt b5)'s effect on CYP activity (IIc). Subsequently, we present a background overview of the history of the molecular characterization of PGRMC1 (III), regarding its structure, expression, and intracellular location (IIIa), and its heme-binding capability and dimerization (IIIb). The next section reflects the different effects PGRMC1 may have on CYP activity (IV), presenting a description of studies on the direct effects on CYP activity (IVa), and a summary of pathways in which PGRMC1's involvement may indirectly affect CYP activity (IVb). The last section of the review is focused on the current challenges of research on the effect of PGRMC1 on CYP activity (V), presenting some future perspectives of research in the field (VI).
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Affiliation(s)
- Isabel S. Barata
- Department of Pediatrics, Division of Endocrinology, Diabetology and Metabolism, University Children’s Hospital, University of Bern, 3010 Bern, Switzerland;
- Translational Hormone Research Program, Department of Biomedical Research, University of Bern, 3010 Bern, Switzerland
- Graduate School for Cellular and Biomedical Sciences, University of Bern, 3012 Bern, Switzerland
| | - José Rueff
- ToxOmics, NOVA Medical School, Faculdade de Ciências Médicas, NMS|FCM, Universidade NOVA de Lisboa, Campo Mártires da Pátria 130, 1169-056 Lisboa, Portugal;
| | - Michel Kranendonk
- ToxOmics, NOVA Medical School, Faculdade de Ciências Médicas, NMS|FCM, Universidade NOVA de Lisboa, Campo Mártires da Pátria 130, 1169-056 Lisboa, Portugal;
| | - Francisco Esteves
- ToxOmics, NOVA Medical School, Faculdade de Ciências Médicas, NMS|FCM, Universidade NOVA de Lisboa, Campo Mártires da Pátria 130, 1169-056 Lisboa, Portugal;
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Barakizou H, Chaieb S. Familial Psychomotor Delay of an Uncommon Cause: Type II Congenital Methemoglobinemia. Clin Med Insights Pediatr 2024; 18:11795565241229007. [PMID: 38303731 PMCID: PMC10832405 DOI: 10.1177/11795565241229007] [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: 07/18/2023] [Accepted: 01/10/2024] [Indexed: 02/03/2024] Open
Abstract
Methemoglobinemia is due to oxidization of divalent ferro-iron of hemoglobin to ferri-iron of methemoglobin (MetHb) which is incapable of transferring oxygen to tissues. This disease may be acquired by intoxication with oxidizing agents or inherited with a mutation of CYB5R3, the gene coding for the methemoglobin reductase or cytochrome B5 reductase 3 responsible for the reduction of MetHb to hemoglobin. We report the case of 2 sisters aged respectively of 15 and 8 months. They were born to a second-degree consanguineous marriage with a history of precocious and unexplained deaths in 3 relatives. Both sisters presented neurological features including psychomotor retardation, microcephaly, and axial hypotonia. Cerebral magnetic resonance imaging revealed cerebral atrophy in both cases associated with hypoplasia of the corpus callosum in the younger child. The association of neurological disability, cyanosis, and hypoxemia prompted a search for methemoglobinemia, with MetHB levels respectively of 26% and 15.8%in the 2 sisters. Initial treatment was based on methylene blue, then ascorbic acid. The genetic study revealed a c.463+8G>C mutation of CYB5R3 confirming the diagnosis of methemoglobinemia type II. The diagnosis of methemoglobinemia, although rare, should be considered in the presence of psychomotor retardation with cyanosis and subacute onset hypoxemia, especially in the presence of a family history.
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Affiliation(s)
- Hager Barakizou
- Department of Pediatrics, Military Hospital of Tunis, Tunis, Tunisia
| | - Selma Chaieb
- Department of Pediatrics, Military Hospital of Tunis, Tunis, Tunisia
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Zhang B, Wang Q, Lin Z, Zheng Z, Zhou S, Zhang T, Zheng D, Chen Z, Zheng S, Zhang Y, Lin X, Dong R, Chen J, Qian H, Hu X, Zhuang Y, Zhang Q, Jin Z, Jiang S, Ma Y. A novel glycolysis-related gene signature for predicting the prognosis of multiple myeloma. Front Cell Dev Biol 2023; 11:1198949. [PMID: 37333985 PMCID: PMC10272536 DOI: 10.3389/fcell.2023.1198949] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2023] [Accepted: 05/25/2023] [Indexed: 06/20/2023] Open
Abstract
Background: Metabolic reprogramming is an important hallmark of cancer. Glycolysis provides the conditions on which multiple myeloma (MM) thrives. Due to MM's great heterogeneity and incurability, risk assessment and treatment choices are still difficult. Method: We constructed a glycolysis-related prognostic model by Least absolute shrinkage and selection operator (LASSO) Cox regression analysis. It was validated in two independent external cohorts, cell lines, and our clinical specimens. The model was also explored for its biological properties, immune microenvironment, and therapeutic response including immunotherapy. Finally, multiple metrics were combined to construct a nomogram to assist in personalized prediction of survival outcomes. Results: A wide range of variants and heterogeneous expression profiles of glycolysis-related genes were observed in MM. The prognostic model behaved well in differentiating between populations with various prognoses and proved to be an independent prognostic factor. This prognostic signature closely coordinated with multiple malignant features such as high-risk clinical features, immune dysfunction, stem cell-like features, cancer-related pathways, which was associated with the survival outcomes of MM. In terms of treatment, the high-risk group showed resistance to conventional drugs such as bortezomib, doxorubicin and immunotherapy. The joint scores generated by the nomogram showed higher clinical benefit than other clinical indicators. The in vitro experiments with cell lines and clinical subjects further provided convincing evidence for our study. Conclusion: We developed and validated the utility of the MM glycolysis-related prognostic model, which provides a new direction for prognosis assessment, treatment options for MM patients.
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Affiliation(s)
- Bingxin Zhang
- Department of Hematology, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Quanqiang Wang
- Department of Hematology, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Zhili Lin
- Department of Hematology, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Ziwei Zheng
- Department of Hematology, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Shujuan Zhou
- Department of Hematology, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Tianyu Zhang
- Department of Hematology, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Dong Zheng
- Department of Hematology, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Zixing Chen
- Department of Hepatobiliary Surgery, The Second Affiliated Hospital and Yuying Children’s Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Sisi Zheng
- Department of Hematology, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Yu Zhang
- Department of Hematology, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Xuanru Lin
- Department of Hematology, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Rujiao Dong
- Department of Hematology, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Jingjing Chen
- Department of Hematology, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Honglan Qian
- Department of Hematology, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Xudong Hu
- Department of Hematology, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Yan Zhuang
- Department of Hematology, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Qianying Zhang
- Department of Hematology, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Zhouxiang Jin
- Department of Hepatobiliary Surgery, The Second Affiliated Hospital and Yuying Children’s Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Songfu Jiang
- Department of Hematology, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Yongyong Ma
- Department of Hematology, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China
- Key Laboratory of Intelligent Treatment and Life Support for Critical Diseases of Zhejiang Province, Wenzhou, Zhejiang, China
- Zhejiang Engineering Research Center for Hospital Emergency and Process Digitization, Wenzhou, Zhejiang, China
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4
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Cai Z, Shao Y, Wu Y. Middle ear cholesteatoma resection under general anesthesia in patients with congenital methemoglobinemia: A case report. Medicine (Baltimore) 2023; 102:e33561. [PMID: 37058021 PMCID: PMC10101292 DOI: 10.1097/md.0000000000033561] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Accepted: 03/29/2023] [Indexed: 04/15/2023] Open
Abstract
RATIONALE Congenital methemoglobinemia is a rare cyanosis cause that can be manifested in affected individuals. We report a case of congenital methemoglobinemia after middle ear cholesteatoma resection under general anesthesia. PATIENT CONCERNS The primary concern of the patient is to safely perform cholesteatoma resection of the middle ear to reduce the pain associated with years of surgery and to survive the perioperative period. DIAGNOSES Congenital methemoglobinemia type 1. INTERVENTIONS The patient underwent general anesthesia and cholesteatoma resection of the middle ear. OUTCOMES The patient successfully underwent cholesteatoma resection in the middle ear under general anesthesia and went through the perioperative period smoothly, and successfully returned to society. LESSONS For patients requiring general anesthesia complicated with rare methemoglobinemia, we improve the awareness of crisis and make comprehensive preparation and monitoring, learn the pathophysiological mechanism related to the disease, so as to protect the operation of methemoglobin patients under general anesthesia.
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Affiliation(s)
- Zenghua Cai
- Department of Anesthesiology, Bethune International Peace Hospital, Shijiazhuang, China
| | - Yu Shao
- Department of Anesthesiology, Bethune International Peace Hospital, Shijiazhuang, China
| | - Yu Wu
- Department of Anesthesiology, Bethune International Peace Hospital, Shijiazhuang, China
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Paini TRD, Uchimura JYT, Sato F, Medina Neto A, Shimauti ELT, Baesso ML, Hidalgo MM, Dos Santos MLA, Previdelli ITS, Pascotto RC. Technique for Darkening of Extracted Teeth Simulating Pulpal Necrosis Discoloration. Clin Cosmet Investig Dent 2022; 14:103-112. [PMID: 35509813 PMCID: PMC9059876 DOI: 10.2147/ccide.s361230] [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: 02/09/2022] [Accepted: 04/09/2022] [Indexed: 11/23/2022] Open
Abstract
Background The use of discolored teeth is required to test whitening products, and it is difficult to obtain them, given their scarcity. Objective To present a technique for in vitro darkening of extracted teeth simulating pulpal necrosis discoloration. Materials and Methods Hemolysates I and II from human blood were subjected or not to laser irradiation (442 nm) for 1 h. The concentration of oxyhemoglobin (O2Hb) was analyzed by ultraviolet/visible spectroscopy, and the conversion of O2Hb to methemoglobin (MetHb) by transmission spectroscopy was assessed immediately and after 3 and 40 days. For darkening evaluation, bovine incisors were divided into two groups (n = 25), and their pulp chambers were filled with hemolysate solution II (HSII) and hemolysate II solution + laser (HSII+L). After storage in artificial saliva for 40 days at 37°C, color changes were measured by a colorimeter and ΔE was compared with the NBS parameters. Data were analyzed using a mixed linear model (α=5%). Results HSII+L presented the lowest O2Hb and higher MetHb. The conversion of O2Hb to MetHb in HSII+L was 42% higher than in HSII. Both groups were effective in darkening the teeth, according to the NBS. Darkening stabilized from day 35. HSII promoted a marked color difference. Conclusion The proposed technique was effective in darkening the extracted teeth simulating necrosis discoloration for in vitro models.
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Affiliation(s)
- Thais R D Paini
- Department of Dentistry, State University of Maringa, Maringá, PR, Brazil
| | - Joana Y T Uchimura
- Department of Dentistry, State University of Maringa, Maringá, PR, Brazil
| | - Francielle Sato
- Department of Physics, State University of Maringa, Maringá, PR, Brazil
| | | | - Eliana L T Shimauti
- Department of Clinical Analysis and Biomedical Science, State University of Maringa, Maringá, PR, Brazil
| | - Mauro L Baesso
- Department of Physics, State University of Maringa, Maringá, PR, Brazil
| | - Mirian M Hidalgo
- Department of Dentistry, State University of Maringa, Maringá, PR, Brazil
| | | | | | - Renata C Pascotto
- Department of Dentistry, State University of Maringa, Maringá, PR, Brazil
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Bartsch L, Schroeder MP, Hänzelmann S, Bastian L, Lázaro-Navarro J, Schlee C, Tanchez JO, Schulze V, Isaakidis K, Rieger MA, Gökbuget N, Eckert C, Serve H, Horstmann M, Schrappe M, Brüggemann M, Baldus CD, Neumann M. An alternative CYB5A transcript is expressed in aneuploid ALL and enriched in relapse. BMC Genom Data 2022; 23:30. [PMID: 35436854 PMCID: PMC9014596 DOI: 10.1186/s12863-022-01041-1] [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: 05/25/2021] [Accepted: 01/25/2022] [Indexed: 11/12/2022] Open
Abstract
Background B-cell precursor acute lymphoblastic leukemia (BCP-ALL) is a genetically heterogenous malignancy with poor prognosis in relapsed adult patients. The genetic basis for relapse in aneuploid subtypes such as near haploid (NH) and high hyperdiploid (HeH) BCP-ALL is only poorly understood. Pathogenic genetic alterations remain to be identified. To this end, we investigated the dynamics of genetic alterations in a matched initial diagnosis-relapse (ID-REL) BCP-ALL cohort. Here, we firstly report the identification of the novel genetic alteration CYB5Aalt, an alternative transcript of CYB5A, in two independent cohorts. Methods We identified CYB5alt in the RNAseq-analysis of a matched ID-REL BCP-ALL cohort with 50 patients and quantified its expression in various molecular BCP-ALL subtypes. Findings were validated in an independent cohort of 140 first diagnosis samples from adult BCP-ALL patients. Derived from patient material, the alternative open reading frame of CYB5Aalt was cloned (pCYB5Aalt) and pCYB5Aalt or the empty vector were stably overexpressed in NALM-6 cells. RNA sequencing was performed of pCYB5Aalt clones and empty vector controls followed by differential expression analysis, gene set enrichment analysis and complementing cell death and viability assays to determine functional implications of CYB5Aalt. Results RNAseq data analysis revealed non-canonical exon usage of CYB5Aalt starting from a previously undescribed transcription start site. CYB5Aalt expression was increased in relapsed BCP-ALL and its occurrence was specific towards the shared gene expression cluster of NH and HeH BCP-ALL in independent cohorts. Overexpression of pCYB5Aalt in NALM-6 cells induced a distinct transcriptional program compared to empty vector controls with downregulation of pathways related to reported functions of CYB5A wildtype. Interestingly, CYB5A wildtype expression was decreased in CYB5Aalt samples in silico and in vitro. Additionally, pCYB5Aalt NALM-6 elicited a more resistant drug response. Conclusions Across all age groups, CYB5Aalt was the most frequent secondary genetic event in relapsed NH and HeH BCP-ALL. In addition to its high subgroup specificity, CYB5Aalt is a novel candidate to be potentially implicated in therapy resistance in NH and HeH BCP-ALL. This is underlined by overexpressing CYB5Aalt providing first evidence for a functional role in BCL2-mediated apoptosis. Supplementary Information The online version contains supplementary material available at 10.1186/s12863-022-01041-1.
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Oral methylene blue treatment in a dog with cytochrome b 5 reductase deficiency and 78, XX testicular disorder of sex development. Top Companion Anim Med 2022; 49:100649. [PMID: 35202847 DOI: 10.1016/j.tcam.2022.100649] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Revised: 02/09/2022] [Accepted: 02/17/2022] [Indexed: 11/20/2022]
Abstract
A 6-month-old mixed breed dog was referred for evaluation of a potential disorder of sex development (DSD) and lower than expected energy level. Genitourinary examination revealed ambiguous external genitalia, hypospadias, and a subtle pouch of skin that resembled an empty scrotum. Corrective surgery was planned and subsequently aborted after cyanosis was identified preoperatively and an arterial blood gas analysis by co-oximetry identified increased methemoglobin (MetHb) concentration (35%, normal < 2%) with normal arterial oxygen tension. Ensuing investigations confirmed hereditary methemoglobinemia caused by cytochrome b5 reductase (CYB5R) deficiency via molecular genetic (Arg219Pro homozygous variant in CYB5R3 gene) and biochemical (cytochrome b5 reductase enzyme activity of 8% [normal, 100% activity] testing. Karyotyping and molecular analysis of sex chromosomes revealed the dog was genetically female with a normal female karyotype (78,XX), and was negative for the Y-linked SRY gene and positive for the X-linked androgen receptor gene. Methylene blue (MB, 3.3 mg/kg per os [PO] q24 h) was administered and the MetHb concentration decreased to 9% within 14 days. Urogenital revision surgery proceeded without complication and the dog was maintained on MB (3-4 mg/kg PO q24 h) long-term without adverse effects. This is the first report to describe the use of PO MB to decrease MetHb concentrations in a dog with CYB5R deficiency in preparation for anesthesia and highlights its potential as a viable alternative to the intravenous formulation for elective procedures. In addition, this report describes the clinical, molecular, imaging, surgical, and macroscopic and microscopic pathological features of a dog with SRY-negative, 78,XX testicular DSD.
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8
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Iolascon A, Bianchi P, Andolfo I, Russo R, Barcellini W, Fermo E, Toldi G, Ghirardello S, Rees D, Van Wijk R, Kattamis A, Gallagher PG, Roy N, Taher A, Mohty R, Kulozik A, De Franceschi L, Gambale A, De Montalembert M, Forni GL, Harteveld CL, Prchal J. Recommendations for diagnosis and treatment of methemoglobinemia. Am J Hematol 2021; 96:1666-1678. [PMID: 34467556 PMCID: PMC9291883 DOI: 10.1002/ajh.26340] [Citation(s) in RCA: 48] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Revised: 08/24/2021] [Accepted: 08/25/2021] [Indexed: 02/03/2023]
Abstract
Methemoglobinemia is a rare disorder associated with oxidization of divalent ferro‐iron of hemoglobin (Hb) to ferri‐iron of methemoglobin (MetHb). Methemoglobinemia can result from either inherited or acquired processes. Acquired forms are the most common, mainly due to the exposure to substances that cause oxidation of the Hb both directly or indirectly. Inherited forms are due either to autosomal recessive variants in the CYB5R3 gene or to autosomal dominant variants in the globin genes, collectively known as HbM disease. Our recommendations are based on a systematic literature search. A series of questions regarding the key signs and symptoms, the methods for diagnosis, the clinical management in neonatal/childhood/adulthood period, and the therapeutic approach of methemoglobinemia were formulated and the relative recommendations were produced. An agreement was obtained using a Delphi‐like approach and the experts panel reached a final consensus >75% of agreement for all the questions.
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Affiliation(s)
- Achille Iolascon
- Dipartimento di Medicina Molecolare e Biotecnologie Mediche Università degli Studi di Napoli Federico II Napoli Italy
- CEINGE Biotecnologie Avanzate Napoli Italy
| | - Paola Bianchi
- UOS Fisiopatologia delle Anemie, UO Ematologia Fondazione IRCCS Ca Granda Ospedale Maggiore Policlinico Milano Milan Italy
| | - Immacolata Andolfo
- Dipartimento di Medicina Molecolare e Biotecnologie Mediche Università degli Studi di Napoli Federico II Napoli Italy
- CEINGE Biotecnologie Avanzate Napoli Italy
| | - Roberta Russo
- Dipartimento di Medicina Molecolare e Biotecnologie Mediche Università degli Studi di Napoli Federico II Napoli Italy
- CEINGE Biotecnologie Avanzate Napoli Italy
| | - Wilma Barcellini
- UOS Fisiopatologia delle Anemie, UO Ematologia Fondazione IRCCS Ca Granda Ospedale Maggiore Policlinico Milano Milan Italy
| | - Elisa Fermo
- UOS Fisiopatologia delle Anemie, UO Ematologia Fondazione IRCCS Ca Granda Ospedale Maggiore Policlinico Milano Milan Italy
| | - Gergely Toldi
- Department of Neonatology Birmingham Women's and Children's Hospital Birmingham UK
| | - Stefano Ghirardello
- Neonatal Intensive Care Unit Fondazione IRCCS Policlinico San Matteo Pavia Italy
| | - Davis Rees
- King's College Hospital King's College London London UK
| | - Richard Van Wijk
- Central Diagnostic Laboratory University Medical Center Utrecht, Utrecht University Utrecht The Netherlands
| | - Antonis Kattamis
- First Department of Pediatrics University of Athens Athens Greece
| | - Patrick G. Gallagher
- Departments of Pediatrics, Pathology, and Genetics Yale University New Haven Connecticut USA
| | - Noemi Roy
- Department of Haematology, Oxford University Hospitals NHS Foundation Trust; NIHR BRC Blood Theme; Department of Haematology Oxford UK
| | - Ali Taher
- Division of Hematology and Oncology, Department of Internal Medicine American University of Beirut Medical Center Beirut Lebanon
| | - Razan Mohty
- Division of Hematology and Oncology, Department of Internal Medicine American University of Beirut Medical Center Beirut Lebanon
| | - Andreas Kulozik
- Department of Pediatric Oncology, Hematology and Immunology University of Heidelberg, Hopp‐ Children's Cancer Research Center (KiTZ) Heidelberg Germany
| | - Lucia De Franceschi
- Department of Medicine University of Verona, and Azienda Ospedaliera Universitaria Verona Verona Italy
| | - Antonella Gambale
- CEINGE Biotecnologie Avanzate Napoli Italy
- Department of Laboratory Medicine (DAIMedLab), UOC Medical Genetics ‘Federico II’ University Hospital Naples Italy
| | - Mariane De Montalembert
- Pédiatrie générale et maladies infectieuses Centre de référence de la drépanocytose, Hôpital Necker‐Enfants Malades, APHP Paris Paris France
| | | | - Cornelis L. Harteveld
- Department of Clinical Genetics/LDGA Leiden University Medical Center Leiden The Netherlands
| | - Josef Prchal
- Hematology University of Utah & Huntsman Cancer Center Salt Lake City Utah USA
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Ri H, Park Y, Jeon Y. Anesthetic experience: congenital methemoglobinemia due to hemoglobin M. J Dent Anesth Pain Med 2021; 21:471-474. [PMID: 34703896 PMCID: PMC8520833 DOI: 10.17245/jdapm.2021.21.5.471] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Revised: 08/20/2021] [Accepted: 09/01/2021] [Indexed: 11/15/2022] Open
Abstract
Methemoglobinemia is rare. It is classified into two types: congenital methemoglobinemia and acquired methemoglobinemia. Methemoglobin is incapable of binding oxygen, leading to complications such as cyanosis, dyspnea, headache, and heart failure. In the present case, a 35-year-old man with congenital methemoglobinemia underwent general anesthesia for thyroidectomy. The patient was diagnosed with hemoglobin M at 7 years of age. Ventilation was performed with FiO2 1.0. Arterial blood gas analysis showed that the pH was 7.4, PaO2 439 mmHg, PaCO2 40.5 mmHg, oxyhemoglobin level of 83.2%, and methemoglobin level of 15.5%. The patient had a stable course, although cyanosis was observed during surgery.
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Affiliation(s)
- Hyunsu Ri
- Department of Anesthesiology and Pain Medicine, Kyungpook National University Hospital, Daegu, Republic of Korea
| | - Youngje Park
- Department of Anesthesiology and Pain Medicine, Kyungpook National University Hospital, Daegu, Republic of Korea
| | - Younghoon Jeon
- Department of Anesthesiology and Pain Medicine, Kyungpook National University Hospital, Daegu, Republic of Korea.,Department of Anesthesiology and Pain Medicine, School of Dentistry, Kyungpook National University, Daegu, Republic of Korea
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Miller WL. Steroidogenic electron-transfer factors and their diseases. Ann Pediatr Endocrinol Metab 2021; 26:138-148. [PMID: 34610701 PMCID: PMC8505039 DOI: 10.6065/apem.2142154.077] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/07/2021] [Accepted: 08/11/2021] [Indexed: 01/01/2023] Open
Abstract
Most steroidogenesis disorders are caused by mutations in genes encoding the steroidogenic enzymes, but work in the past 20 years has identified related disorders caused by mutations in the genes encoding the cofactors that transport electrons from NADPH to P450 enzymes. Most P450s are microsomal and require electron donation by P450 oxidoreductase (POR); by contrast, mitochondrial P450s require electron donation via ferredoxin reductase (FdxR) and ferredoxin (Fdx). POR deficiency is the most common and best-described of these new forms of congenital adrenal hyperplasia. Severe POR deficiency is characterized by the Antley-Bixler skeletal malformation syndrome and genital ambiguity in both sexes, and hence is easily recognized, but mild forms may present only with infertility and subtle disorders of steroidogenesis. The common POR polymorphism A503V reduces catalysis by P450c17 (17-hydroxylase/17,20-lyase) and the principal drugmetabolizing P450 enzymes. The 17,20-lyase activity of P450c17 requires the allosteric action of cytochrome b5, which promotes interaction of P450c17 with POR, with consequent electron transfer. Rare b5 mutations are one of several causes of 17,20-lyase deficiency. In addition to their roles with steroidogenic mitochondrial P450s, Fdx and FdxR participate in the synthesis of iron-sulfur clusters used by many enzymes. Disruptions in the assembly of Fe-S clusters is associated with Friedreich ataxia and Parkinson disease. Recent work has identified mutations in FdxR in patients with neuropathic hearing loss and visual impairment, somewhat resembling the global neurologic disorders seen with mitochondrial diseases. Impaired steroidogenesis is to be expected in such individuals, but this has not yet been studied.
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Affiliation(s)
- Walter L. Miller
- Department of Pediatrics, Center for Reproductive Sciences and Institute for Human Genetics, University of California, San Francisco, CA, USA,Address for correspondence: Walter L. Miller Department of Pediatrics, University of California, San Francisco, San Francisco CA 94143, USA
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11
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Dynamic CTCF binding directly mediates interactions among cis-regulatory elements essential for hematopoiesis. Blood 2021; 137:1327-1339. [PMID: 33512425 DOI: 10.1182/blood.2020005780] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2020] [Accepted: 12/05/2020] [Indexed: 11/20/2022] Open
Abstract
While constitutive CCCTC-binding factor (CTCF)-binding sites are needed to maintain relatively invariant chromatin structures, such as topologically associating domains, the precise roles of CTCF to control cell-type-specific transcriptional regulation remain poorly explored. We examined CTCF occupancy in different types of primary blood cells derived from the same donor to elucidate a new role for CTCF in gene regulation during blood cell development. We identified dynamic, cell-type-specific binding sites for CTCF that colocalize with lineage-specific transcription factors. These dynamic sites are enriched for single-nucleotide polymorphisms that are associated with blood cell traits in different linages, and they coincide with the key regulatory elements governing hematopoiesis. CRISPR-Cas9-based perturbation experiments demonstrated that these dynamic CTCF-binding sites play a critical role in red blood cell development. Furthermore, precise deletion of CTCF-binding motifs in dynamic sites abolished interactions of erythroid genes, such as RBM38, with their associated enhancers and led to abnormal erythropoiesis. These results suggest a novel, cell-type-specific function for CTCF in which it may serve to facilitate interaction of distal regulatory emblements with target promoters. Our study of the dynamic, cell-type-specific binding and function of CTCF provides new insights into transcriptional regulation during hematopoiesis.
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12
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Dumontet T, Martinez A. Adrenal androgens, adrenarche, and zona reticularis: A human affair? Mol Cell Endocrinol 2021; 528:111239. [PMID: 33676986 DOI: 10.1016/j.mce.2021.111239] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Revised: 02/11/2021] [Accepted: 03/01/2021] [Indexed: 12/11/2022]
Abstract
In humans, reticularis cells of the adrenal cortex fuel the production of androgen steroids, constituting the driver of numerous morphological changes during childhood. These steps are considered a precocious stage of sexual maturation and are grouped under the term "adrenarche". This review describes the molecular and enzymatic characteristics of the zona reticularis, along with the possible signals and mechanisms that control its emergence and the associated clinical features. We investigate the differences between species and discuss new studies such as genetic lineage tracing and transcriptomic analysis, highlighting the rodent inner cortex's cellular and molecular heterogeneity. The recent development and characterization of mouse models deficient for Prkar1a presenting with adrenocortical reticularis-like features prompt us to review our vision of the mouse adrenal gland maturation. We expect these new insights will help increase our understanding of the adrenarche process and the pathologies associated with its deregulation.
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Affiliation(s)
- Typhanie Dumontet
- Department of Internal Medicine, Division of Metabolism, Endocrinology, and Diabetes, University of Michigan, Ann Arbor, MI, USA; Training Program in Organogenesis, Center for Cell Plasticity and Organ Design, University of Michigan, Ann Arbor, MI, USA.
| | - Antoine Martinez
- Génétique, Reproduction et Développement (GReD), Centre National de La Recherche Scientifique CNRS, Institut National de La Santé & de La Recherche Médicale (INSERM), Université Clermont-Auvergne (UCA), France.
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13
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Jaffey JA, Reading NS, Abdulmalik O, Kreisler R, Bullock G, Wiest A, Villani NA, Mhlanga-Mutangadura T, Johnson GS, Cohn LA, Isaza N, Harvey JW, Giger U. Clinical, metabolic, and molecular genetic characterization of hereditary methemoglobinemia caused by cytochrome b 5 reductase deficiency in 30 dogs. Sci Rep 2020; 10:21399. [PMID: 33293645 PMCID: PMC7723051 DOI: 10.1038/s41598-020-78391-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Accepted: 11/24/2020] [Indexed: 11/09/2022] Open
Abstract
Genotype–phenotype correlations of humans and dogs with hereditary methemoglobinemia are not yet well characterized. We determined total hemoglobin and methemoglobin (MetHb) concentrations, cytochrome b5 reductase (CYB5R) enzyme activities, genotypes, and clinical signs in 30 dogs with persistent cyanosis without cardiopulmonary disease. Erythrocytic CYB5R enzyme activities were low in all dogs assayed. Owner-reported quality of life ranged from subclinical to occasional exertional syncope. Two previously reported and two novel CYB5R3 missense variants were identified among the methemoglobinemic cohort and were predicted to impair enzyme function. Two variants were recurrent: a homozygous Ile194Leu substitution was found in Pomeranians and other small dogs, and a homozygous Arg219Pro change occurred predominately in pit bull terriers. The other two variants were Thr202Ala and Gly76Ser substitutions in single dogs. Of the two common CYB5R3 genotypes, Arg219Pro was associated with a more severe metabolic phenotype. We conclude that CYB5R3 deficiency is the predominate cause of canine hereditary methemoglobinemia. Although this finding is unlikely to alter the clinical approach to hereditary methemoglobinemia in dogs, it demonstrates the possibility of how genotype–phenotype cohort analysis might facilitate precision medicine in the future in veterinary medicine.
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Affiliation(s)
- J A Jaffey
- Department of Specialty Medicine, College of Veterinary Medicine, Midwestern University, Glendale, AZ, USA. .,Department of Veterinary Medicine and Surgery, Veterinary Health Center, University of Missouri, Columbia, MO, USA.
| | - N S Reading
- Institute for Clinical and Experimental Pathology, ARUP Laboratories, Salt Lake City, UT, USA
| | - O Abdulmalik
- Division of Hematology, The Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - R Kreisler
- Department of Pathology and Population Medicine, College of Veterinary Medicine, Midwestern University, Glendale, AZ, USA
| | - G Bullock
- Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, MO, USA
| | - A Wiest
- Section of Medical Genetics (PennGen), School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - N A Villani
- Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, MO, USA
| | - T Mhlanga-Mutangadura
- Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, MO, USA
| | - G S Johnson
- Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, MO, USA
| | - L A Cohn
- Department of Veterinary Medicine and Surgery, Veterinary Health Center, University of Missouri, Columbia, MO, USA
| | - N Isaza
- Department of Small Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, Gainesville, FL, USA
| | - J W Harvey
- Department of Physiological Sciences, College of Veterinary Medicine, University of Florida, Gainesville, FL, USA
| | - U Giger
- Section of Medical Genetics (PennGen), School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, USA
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14
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Management of methemoglobinemia secondary to iNO use in a newborn with congenital diaphragmatic hernia. JOURNAL OF PEDIATRIC SURGERY CASE REPORTS 2020. [DOI: 10.1016/j.epsc.2020.101457] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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15
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de Vere F, Moores R, Dhadwal K, Karra E. A severe case of methaemoglobinaemia in a Brazilian hairdresser. BMJ Case Rep 2020; 13:e232735. [PMID: 31969408 PMCID: PMC7021157 DOI: 10.1136/bcr-2019-232735] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/20/2019] [Indexed: 11/03/2022] Open
Abstract
Methaemoglobinaemia is an extremely rare condition with multiple causes, both genetic and acquired. We present a severe case of methaemoglobinaemia occurring in a Brazilian hairdresser working in the UK. She presented after several days of preparing popular 'Brazilian blowdry' treatments for customers at a hair salon. She had been exposed to multiple volatile chemicals, including formaldehyde, without any respiratory protection, and we postulate that this may have caused her illness. If so, this would be the first published case of methaemoglobinaemia caused by exposure to the volatile components of beauty products.
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Affiliation(s)
| | - Rachel Moores
- Infectious Diseases and Acute Medicine, Royal Free Hospital, Hampstead, London, UK
| | | | - Efthimia Karra
- Endocrinology and Diabetes, Royal Free Hospital, Hampstead, London, UK
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16
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Storbeck KH, Schiffer L, Baranowski ES, Chortis V, Prete A, Barnard L, Gilligan LC, Taylor AE, Idkowiak J, Arlt W, Shackleton CHL. Steroid Metabolome Analysis in Disorders of Adrenal Steroid Biosynthesis and Metabolism. Endocr Rev 2019; 40:1605-1625. [PMID: 31294783 PMCID: PMC6858476 DOI: 10.1210/er.2018-00262] [Citation(s) in RCA: 61] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/02/2018] [Accepted: 06/04/2019] [Indexed: 01/01/2023]
Abstract
Steroid biosynthesis and metabolism are reflected by the serum steroid metabolome and, in even more detail, by the 24-hour urine steroid metabolome, which can provide unique insights into alterations of steroid flow and output indicative of underlying conditions. Mass spectrometry-based steroid metabolome profiling has allowed for the identification of unique multisteroid signatures associated with disorders of steroid biosynthesis and metabolism that can be used for personalized approaches to diagnosis, differential diagnosis, and prognostic prediction. Additionally, steroid metabolome analysis has been used successfully as a discovery tool, for the identification of novel steroidogenic disorders and pathways as well as revealing insights into the pathophysiology of adrenal disease. Increased availability and technological advances in mass spectrometry-based methodologies have refocused attention on steroid metabolome profiling and facilitated the development of high-throughput steroid profiling methods soon to reach clinical practice. Furthermore, steroid metabolomics, the combination of mass spectrometry-based steroid analysis with machine learning-based approaches, has facilitated the development of powerful customized diagnostic approaches. In this review, we provide a comprehensive up-to-date overview of the utility of steroid metabolome analysis for the diagnosis and management of inborn disorders of steroidogenesis and autonomous adrenal steroid excess in the context of adrenal tumors.
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Affiliation(s)
- Karl-Heinz Storbeck
- Department of Biochemistry, Stellenbosch University, Stellenbosch, South Africa
- Institute of Metabolism and Systems Research, University of Birmingham, Birmingham, United Kingdom
| | - Lina Schiffer
- Institute of Metabolism and Systems Research, University of Birmingham, Birmingham, United Kingdom
| | - Elizabeth S Baranowski
- Institute of Metabolism and Systems Research, University of Birmingham, Birmingham, United Kingdom
- Centre for Endocrinology, Diabetes and Metabolism, Birmingham Health Partners, Birmingham, United Kingdom
- Department of Paediatric Endocrinology and Diabetes, Birmingham Women’s and Children’s Hospital NHS Foundation Trust, Birmingham, United Kingdom
| | - Vasileios Chortis
- Institute of Metabolism and Systems Research, University of Birmingham, Birmingham, United Kingdom
- Centre for Endocrinology, Diabetes and Metabolism, Birmingham Health Partners, Birmingham, United Kingdom
- Department of Endocrinology, Queen Elizabeth Hospital, University Hospitals Birmingham NHS Foundation Trust, Birmingham, United Kingdom
| | - Alessandro Prete
- Institute of Metabolism and Systems Research, University of Birmingham, Birmingham, United Kingdom
- Centre for Endocrinology, Diabetes and Metabolism, Birmingham Health Partners, Birmingham, United Kingdom
- Department of Endocrinology, Queen Elizabeth Hospital, University Hospitals Birmingham NHS Foundation Trust, Birmingham, United Kingdom
| | - Lise Barnard
- Department of Biochemistry, Stellenbosch University, Stellenbosch, South Africa
| | - Lorna C Gilligan
- Institute of Metabolism and Systems Research, University of Birmingham, Birmingham, United Kingdom
| | - Angela E Taylor
- Institute of Metabolism and Systems Research, University of Birmingham, Birmingham, United Kingdom
| | - Jan Idkowiak
- Institute of Metabolism and Systems Research, University of Birmingham, Birmingham, United Kingdom
- Centre for Endocrinology, Diabetes and Metabolism, Birmingham Health Partners, Birmingham, United Kingdom
- Department of Paediatric Endocrinology and Diabetes, Birmingham Women’s and Children’s Hospital NHS Foundation Trust, Birmingham, United Kingdom
| | - Wiebke Arlt
- Institute of Metabolism and Systems Research, University of Birmingham, Birmingham, United Kingdom
- Centre for Endocrinology, Diabetes and Metabolism, Birmingham Health Partners, Birmingham, United Kingdom
- Department of Endocrinology, Queen Elizabeth Hospital, University Hospitals Birmingham NHS Foundation Trust, Birmingham, United Kingdom
- NIHR Birmingham Biomedical Research Centre, University Hospitals Birmingham NHS Foundation Trust and University of Birmingham, Birmingham, United Kingdom
| | - Cedric H L Shackleton
- Institute of Metabolism and Systems Research, University of Birmingham, Birmingham, United Kingdom
- UCSF Benioff Children’s Hospital Oakland Research Institute, Oakland, California
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17
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Leung MT, Cheung HN, Iu YP, Choi CH, Tiu SC, Shek CC. Isolated 17,20-Lyase Deficiency in a CYB5A Mutated Female With Normal Sexual Development and Fertility. J Endocr Soc 2019; 4:bvz016. [PMID: 32051920 PMCID: PMC7007803 DOI: 10.1210/jendso/bvz016] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Indexed: 12/05/2022] Open
Abstract
Isolated 17,20-lyase deficiency may be caused by mutations in the CYP17A1 (coding for cytochrome P450c17), POR (coding for cytochrome P450 oxidoreductase) and CYB5A (coding for microsomal cytochrome b5) genes. Of these, mutations in the CYB5A gene have thus far only been described in genetic males who presented with methemoglobinemia and 46,XY disorders of sex development (DSD) due to 17,20-lyase deficiency. A 24-year-old Chinese woman presented to the hematology outpatient clinic with purplish discoloration of fingers, toes, and lips since childhood. Investigations confirmed methemoglobinemia. A homozygous c.105C>G (p.Tyr35Ter) nonsense mutation was detected in the CYB5A gene. Hormonal studies showed isolated 17,20-lyase deficiency. Interestingly, she had a completely normal female phenotype with no DSD, normal pubertal development, and spontaneous pregnancy giving birth uneventfully to a healthy female infant. The sex hormone-related features of genetic females with 17,20-lyase deficiency due to cytochrome b5 gene mutation appear to differ from that of females with 17,20-lyase deficiency caused by other genetic defects who presented with hypergonadotropic hypogonadism and infertility and differ from genetic males with the same mutation.
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Affiliation(s)
- Mei Tik Leung
- Department of Pathology, Queen Elizabeth Hospital, Jordan, Kowloon, Hong Kong
| | - Hoi Ning Cheung
- Department of Pathology, Queen Elizabeth Hospital, Jordan, Kowloon, Hong Kong
| | - Yan Ping Iu
- Department of Pathology, Queen Elizabeth Hospital, Jordan, Kowloon, Hong Kong
| | - Cheung Hei Choi
- Department of Medicine, Queen Elizabeth Hospital, Jordan, Kowloon, Hong Kong
| | - Sau Cheung Tiu
- Department of Medicine, Queen Elizabeth Hospital, Jordan, Kowloon, Hong Kong
| | - Chi Chung Shek
- Department of Pathology, Queen Elizabeth Hospital, Jordan, Kowloon, Hong Kong
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18
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Khan FA, McIntyre C, Khan AM, Maslov A. Headache and Methemoglobinemia. Headache 2019; 60:291-297. [PMID: 31724752 DOI: 10.1111/head.13696] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/23/2019] [Indexed: 11/27/2022]
Abstract
AIM This basic review is intended to summarize the current knowledge of methemoglobinemia as an important cause of secondary headache with the hope of generating a growing interest in studying this phenomenon. BACKGROUND We describe the pathological underpinnings of headaches generated by hypoxia. Possible mechanisms include cerebral vasodilation-associated stretching of the vessel nociceptors, sensitization of perivascular nociceptors mediated by nitric oxide, cerebral calcitonin gene-related peptide, activation of the cyclic adenosine monophosphate pathway, cortical spreading depression, disruption of the blood-brain barrier, and neurogenic inflammation. We review the clinical features, pathophysiology, and management of methemoglobinemia. We conducted a literature review of reports of symptomatic methemoglobinemia with headache. In addition, we describe a case report of a patient who presented with an acute onset of severe holocranial headache associated with rapidly progressive perioral paresthesia, cyanosis in lips and hands, nausea, and mild dyspnea on exertion. These features can be misinterpreted as an acute attack of migraine with pain-related hyperventilation syndrome and anxiety leading to clinically detrimental delay in the management of the progressive hypoxia. Her symptoms resolved following treatment with methylene blue. The complex relationship of migraine and hypoxia-related headaches is also reviewed. We propose that methemoglobinemia-associated headaches are possibly generated by stretching of the nociceptor nerve endings during cerebral vasodilation and hypoxia-mediated oxidative stress. CONCLUSIONS The case highlights the need to broaden the formulated differential diagnosis of an acute onset severe holocranial headache and pay careful attention to other signs and symptoms that may provide hints on potential mechanism(s) for secondary headaches. We provide justification for the need to incorporate "Headache attributed to Methemoglobinemia" as a subtype under the section "Headache attributed to hypoxia and/or hypercapnia" of the International Classification of Headache Disorders to support clinical decision making.
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Affiliation(s)
- Fawad Ahmed Khan
- The McCasland Family Comprehensive Headache Center, Ochsner Neuroscience Institute, Ochsner Clinic Foundation, New Orleans, LA, USA.,The University of Queensland School of Medicine, Ochsner Clinical School, New Orleans, LA, USA.,Tulane University School of Medicine, New Orleans, LA, USA
| | - Caley McIntyre
- The University of Queensland School of Medicine, Ochsner Clinical School, New Orleans, LA, USA.,Department of Hospital Medicine, Ochsner Clinic Foundation, New Orleans, LA, USA
| | - Abdul Mukhtadir Khan
- Department of Pulmonary and Critical Care Medicine, Ochsner Clinic Foundation, New Orleans, LA, USA
| | - Alexander Maslov
- The University of Queensland School of Medicine, Ochsner Clinical School, New Orleans, LA, USA
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19
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Jaffey JA, Reading NS, Giger U, Abdulmalik O, Buckley RM, Johnstone S, Lyons LA. Clinical, metabolic, and genetic characterization of hereditary methemoglobinemia caused by cytochrome b 5 reductase deficiency in cats. J Vet Intern Med 2019; 33:2725-2731. [PMID: 31650629 PMCID: PMC6872605 DOI: 10.1111/jvim.15637] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Accepted: 09/24/2019] [Indexed: 01/24/2023] Open
Abstract
Two non‐pedigreed male castrated cats had persistent cyanosis over a 3‐year observation period. Clinical cardiopulmonary evaluations did not reveal abnormalities, but the blood remained dark after exposure to air. Erythrocytic methemoglobin concentrations were high (~40% of hemoglobin) and cytochrome b5 reductase (CYB5R) activities in erythrocytes were low (≤15% of control). One cat remained intolerant of exertion, and the other cat developed anemia and died due to an unidentified comorbidity. Whole‐genome sequencing revealed a homozygous c.625G>A missense variant (B4:137967506) and a c.232‐1G>C splice acceptor variant (B4:137970815) in CYB5R3, respectively, which were absent in 193 unaffected additional cats. The p.Gly209Ser missense variant likely disrupts a nicotinamide adenine dinucleotide (NADH)‐binding domain, while the splicing error occurs at the acceptor site for exon 4, which likely affects downstream translation of the protein. The 2 novel CYB5R3 variants were associated with methemoglobinemia using clinical, biochemical, genomics, and in silico protein studies. The variant prevalence is unknown in the cat population.
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Affiliation(s)
- Jared A Jaffey
- Department of Veterinary Medicine and Surgery, College of Veterinary Medicine, Midwestern University, Glendale, Arizona
| | - N Scott Reading
- Institute for Clinical and Experimental Pathology, ARUP Laboratories, Salt Lake City, Utah.,Division of Hematology, Department of Internal Medicine, University of Utah School of Medicine, Salt Lake City, Utah.,Department of Pathology, University of Utah School of Medicine, Salt Lake City, Utah
| | - Urs Giger
- Section of Medical Genetics (PennGen), School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Osheiza Abdulmalik
- Division of Hematology, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania
| | - Ruben M Buckley
- Department of Veterinary Medicine and Surgery, College of Veterinary Medicine, University of Missouri, Columbia, Missouri
| | | | - Leslie A Lyons
- Department of Veterinary Medicine and Surgery, College of Veterinary Medicine, University of Missouri, Columbia, Missouri
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20
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Yoo SE, Yi M, Kim WY, Cho SA, Lee SS, Lee SJ, Shin JG. Influences of cytochrome b5 expression and its genetic variant on the activity of CYP2C9, CYP2C19 and CYP3A4. Drug Metab Pharmacokinet 2019; 34:201-208. [PMID: 30992242 DOI: 10.1016/j.dmpk.2019.03.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2018] [Revised: 03/15/2019] [Accepted: 03/27/2019] [Indexed: 11/28/2022]
Abstract
The objective of the present study was to investigate the effects of cytochrome b5 (cytb5) on the drug metabolism catalyzed by CYP2C9, CYP2C19 and CYP3A4. Activities of CYP2C9, CYP2C19, and CYP3A4 were determined by using the prototypical substrates tolbutamide, omeprazole and midazolam, respectively. Cytb5 protein and mRNA contents showed large inter-individual variations with 11- and 6-fold range, respectively. All of three P450s showed an increased activity in proportion to the amount of cytb5 expression. Particularly, CYP3A4 showed the strongest correlation between cytb5 protein amount and the activity, followed by CYP2C9 and CYP2C19. The putative splicing variant, c.288G>A (rs7238987) was identified and was screened in 36 liver tissues by direct DNA sequencing. Liver tissues having a splicing variant exhibited unexpected sizes of cytb5 mRNA and a decreased expression tendency of cytb5 protein compared to the wild-type. A decreased activity in the metabolism of the CYP2C19 substrate omeprazole was observed in liver tissues carrying the splicing variant when compared to the wild-type Cytb5 (P < 0.05). The present results propose that different expression of cytb5 can cause variations in CYP mediated drug metabolism, which may explain, at least in part, the inter-individual difference in drug responses in addition to the CYP genetic polymorphisms.
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Affiliation(s)
- Sung-Eun Yoo
- Department of Pharmacology and PharmacoGenomics Research Center, Inje University College of Medicine, Busan, Republic of Korea
| | - MyeongJin Yi
- Department of Pharmacology and PharmacoGenomics Research Center, Inje University College of Medicine, Busan, Republic of Korea
| | - Woo-Young Kim
- Department of Pharmacology and PharmacoGenomics Research Center, Inje University College of Medicine, Busan, Republic of Korea
| | - Sun-Ah Cho
- Department of Pharmacology and PharmacoGenomics Research Center, Inje University College of Medicine, Busan, Republic of Korea
| | - Sang Seop Lee
- Department of Pharmacology and PharmacoGenomics Research Center, Inje University College of Medicine, Busan, Republic of Korea
| | - Su-Jun Lee
- Department of Pharmacology and PharmacoGenomics Research Center, Inje University College of Medicine, Busan, Republic of Korea.
| | - Jae-Gook Shin
- Department of Pharmacology and PharmacoGenomics Research Center, Inje University College of Medicine, Busan, Republic of Korea; Department of Clinical Pharmacology, Inje University Busan Paik Hospital, Busan, Republic of Korea.
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21
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Ward J, Motwani J, Baker N, Nash M, Ewer AK, Toldi G. Congenital Methemoglobinemia Identified by Pulse Oximetry Screening. Pediatrics 2019; 143:peds.2018-2814. [PMID: 30733239 DOI: 10.1542/peds.2018-2814] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 11/08/2018] [Indexed: 11/24/2022] Open
Abstract
Congenital methemoglobinemia is a rare condition caused by cytochrome b5 reductase deficiency, cytochrome b5 deficiency, or hemoglobin M disease. Newborn pulse oximetry screening was developed for the early detection of critical congenital heart disease; however, it also enables the early identification of other hypoxemic conditions. We present the case of a term neonate who was admitted to the neonatal unit after a failed pulse oximetry screening at 3 hours of age. Oxygen saturations remained between 89% and 92% despite an increase in oxygen therapy. Chest radiograph and echocardiogram results were normal. A capillary blood gas test had normal results except for a raised methemoglobin level of 16%. Improvement was seen on the administration of methylene blue, which also resulted in an increase in oxygen saturations to within normal limits. Further investigation revealed evidence of type I hereditary cytochrome b5 reductase deficiency as a result of a CYB5R3 gene mutation with 2 pathogenic variants involving guanine-to-adenine substitutions. Although mild cyanosis is generally the only symptom of type I disease, patients may later develop associated symptoms, such as fatigue and shortness of breath. If an early diagnosis is missed, these patients are likely to present later with a diagnostic conundrum and be subject to extensive investigation. This case represents the success of pulse oximetry screening in the early identification of subclinical hypoxemia in this infant. After the exclusion of other pathologies, a routine investigation of capillary blood gas provided the information that led to a diagnosis, which allowed for early and effective management.
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Affiliation(s)
| | - Jayashree Motwani
- Haematology, Birmingham Women's and Children's Hospital, Birmingham, United Kingdom; and
| | | | | | - Andrew K Ewer
- Departments of Neonatology and.,Institute of Metabolism and Systems Research, University of Birmingham, Birmingham, United Kingdom
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22
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Osterberg JS, Cammen KM, Schultz TF, Clark BW, Di Giulio RT. Genome-wide scan reveals signatures of selection related to pollution adaptation in non-model estuarine Atlantic killifish (Fundulus heteroclitus). AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2018; 200:73-82. [PMID: 29727773 PMCID: PMC6957077 DOI: 10.1016/j.aquatox.2018.04.017] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/12/2018] [Revised: 04/21/2018] [Accepted: 04/24/2018] [Indexed: 05/09/2023]
Abstract
In many human-altered ecosystems, organisms are increasingly faced with more diverse and complex environmental stressors and pollutant mixtures, to which the adaptations necessary to survive exposure are likely to be numerous and varied. Improving our understanding of the molecular mechanisms that underlie complex polygenic adaptations in natural settings requires significant toxicological, biochemical, physiological, and genomic data rarely available for non-model organisms. Here, we build upon two decades of study of adaptation to anthropogenic pollutants in a population of Atlantic killifish (Fundulus heteroclitus) that inhabits the creosote-contaminated Atlantic Wood Industries Superfund (AW) site on the Elizabeth River, Virginia in the United States. To better understand the genotypes that underlie previously characterized resistance to PCBs and PAHs, we performed Restriction site-Associated DNA sequencing (RADseq) on killifish from AW and two relatively clean reference sites (King's Creek-KC, and Mains Creek-MC). Across the genome, we analyzed over 83,000 loci and 12,000 single nucleotide polymorphisms (SNPs). Shared across both comparisons of killifish from polluted (AW) and relatively unpolluted (KC and MC) sites, we found eight genomic regions with smoothed FST values significantly (p < 0.001) elevated above background. Using the recently published F. heteroclitus reference genome, we identified candidate genes in these significant regions involved in the AHR pathway (e.g. AIP, ARNT1c), as well as genes relating to cardiac structure and function. These genes represent both previously characterized and potentially novel molecular adaptations involved with various aspects of resistance to these environmental toxins.
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Affiliation(s)
- J S Osterberg
- Duke University, Nicholas School of the Environment, Duke Superfund Research Center, Durham, NC, 27708, USA; Duke University, Nicholas School of the Environment, Duke Marine Lab, Beaufort, NC, 28516, USA.
| | - K M Cammen
- Duke University, Nicholas School of the Environment, Duke Marine Lab, Beaufort, NC, 28516, USA
| | - T F Schultz
- Duke University, Nicholas School of the Environment, Duke Marine Lab, Beaufort, NC, 28516, USA
| | - B W Clark
- Duke University, Nicholas School of the Environment, Duke Superfund Research Center, Durham, NC, 27708, USA
| | - R T Di Giulio
- Duke University, Nicholas School of the Environment, Duke Superfund Research Center, Durham, NC, 27708, USA
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23
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Baranowski ES, Arlt W, Idkowiak J. Monogenic Disorders of Adrenal Steroidogenesis. Horm Res Paediatr 2018; 89:292-310. [PMID: 29874650 PMCID: PMC6067656 DOI: 10.1159/000488034] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/03/2018] [Accepted: 02/27/2018] [Indexed: 12/19/2022] Open
Abstract
Disorders of adrenal steroidogenesis comprise autosomal recessive conditions affecting steroidogenic enzymes of the adrenal cortex. Those are located within the 3 major branches of the steroidogenic machinery involved in the production of mineralocorticoids, glucocorticoids, and androgens. This mini review describes the principles of adrenal steroidogenesis, including the newly appreciated 11-oxygenated androgen pathway. This is followed by a description of pathophysiology, biochemistry, and clinical implications of steroidogenic disorders, including mutations affecting cholesterol import and steroid synthesis, the latter comprising both mutations affecting steroidogenic enzymes and co-factors required for efficient catalysis. A good understanding of adrenal steroidogenic pathways and their regulation is crucial as the basis for sound management of these disorders, which in the majority present in early childhood.
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Affiliation(s)
- Elizabeth S. Baranowski
- Institute of Metabolism and Systems Research, University of Birmingham, Birmingham, United Kingdom,Centre for Endocrinology, Diabetes and Metabolism, Birmingham Health Partners, Birmingham, United Kingdom,Department of Paediatric Endocrinology and Diabetes, Birmingham Women's and Children's Hospital NHS Foundation Trust, Birmingham, United Kingdom
| | - Wiebke Arlt
- Institute of Metabolism and Systems Research, University of Birmingham, Birmingham, United Kingdom,Centre for Endocrinology, Diabetes and Metabolism, Birmingham Health Partners, Birmingham, United Kingdom,*Prof. Wiebke Arlt, Institute of Metabolism and Systems Research (IMSR), University of Birmingham, Birmingham B15 2TT (UK), E-Mail
| | - Jan Idkowiak
- Institute of Metabolism and Systems Research, University of Birmingham, Birmingham, United Kingdom,Centre for Endocrinology, Diabetes and Metabolism, Birmingham Health Partners, Birmingham, United Kingdom,Department of Paediatric Endocrinology and Diabetes, Birmingham Women's and Children's Hospital NHS Foundation Trust, Birmingham, United Kingdom
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Shino H, Otsuka-Yamasaki Y, Sato T, Ooi K, Inanami O, Sato R, Yamasaki M. Familial Congenital Methemoglobinemia in Pomeranian Dogs Caused by a Missense Variant in the NADH-Cytochrome B5 Reductase Gene. J Vet Intern Med 2018; 32:165-171. [PMID: 29356095 PMCID: PMC5787195 DOI: 10.1111/jvim.15031] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2017] [Revised: 10/02/2017] [Accepted: 11/29/2017] [Indexed: 01/07/2023] Open
Abstract
Background In veterinary medicine, congenital methemoglobinemia associated with nicotinamide adenine dinucleotide (NADH)‐cytochrome b5 reductase (b5R) deficiency is rare. It has been reported in several breeds of dogs, but little information is available about its etiology. Objectives To analyze the NADH‐cytochrome b5 reductase gene, CYB5R3, in a Pomeranian dog family with methemoglobinemia suspected to be caused by congenital b5R deficiency. Animals Three Pomeranian dogs from a family with methemoglobinemia were analyzed. Five healthy beagles and 5 nonrelated Pomeranian dogs without methemoglobinemia were used as controls. Methods Methemoglobin concentration, b5R activity, and reduced glutathione (GSH) concentration were measured, and a turbidity index was used to evaluate Heinz body formation. The CYB5R3 genes of the affected dog and healthy dogs were analyzed by direct sequencing. Results Methemoglobin concentrations in erythrocytes of the affected dogs were remarkably higher than those of the control dogs. The b5R activity of the affected dogs was notably lower than that of the control dogs. DNA sequencing indicated that this Pomeranian family carried a CYB5R3 gene missense variant (ATC→CTC at codon 194) that resulted in the replacement of isoleucine (Ile) by leucine (Leu). Conclusions and Clinical Importance This dog family had familial congenital methemoglobinemia caused by b5R deficiency, which resulted from a nonsynonymous variant in the CYB5R3 gene. This variation (c.580A>C) led to an amino acid substitution (p.Ile194Leu), and Ile194 was located in the proximal region of the NADH‐binding motif. Our data suggested that this variant in the canine CYB5R3 gene would affect function of the b5R in erythrocytes.
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Affiliation(s)
- H Shino
- Department of Veterinary Medicine, Faculty of Agriculture, Iwate University, Morioka, Iwate, Japan
| | - Y Otsuka-Yamasaki
- Department of Veterinary Medicine, Faculty of Agriculture, Iwate University, Morioka, Iwate, Japan
| | - T Sato
- Estie Animal Hospital, Kooriyama, Fukushima, Japan
| | - K Ooi
- Ooi Animal Hospital, Kooriyama, Fukushima, Japan
| | - O Inanami
- Department of Veterinary Medicine, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo, Hokkaido, Japan
| | - R Sato
- Department of Veterinary Medicine, Faculty of Agriculture, Iwate University, Morioka, Iwate, Japan
| | - M Yamasaki
- Department of Veterinary Medicine, Faculty of Agriculture, Iwate University, Morioka, Iwate, Japan
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25
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Bhatt MR, Khatri Y, Rodgers RJ, Martin LL. Role of cytochrome b5 in the modulation of the enzymatic activities of cytochrome P450 17α-hydroxylase/17,20-lyase (P450 17A1). J Steroid Biochem Mol Biol 2017; 170:2-18. [PMID: 26976652 DOI: 10.1016/j.jsbmb.2016.02.033] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/23/2015] [Revised: 02/25/2016] [Accepted: 02/27/2016] [Indexed: 12/13/2022]
Abstract
Cytochrome b5 (cyt b5) is a small hemoprotein that plays a significant role in the modulation of activities of an important steroidogenic enzyme, cytochrome P450 17α-hydroxylase/17,20-lyase (P450 17A1, CYP17A1). Located in the zona fasciculata and zona reticularis of the adrenal cortex and in the gonads, P450 17A1 catalyzes two different reactions in the steroidogenic pathway; the 17α-hydroxylation and 17,20-lyase, in the endoplasmic reticulum of these respective tissues. The activities of P450 17A1 are regulated by cyt b5 that enhances the 17,20-lyase reaction by promoting the coupling of P450 17A1 and cytochrome P450 reductase (CPR), allosterically. Cyt b5 can also act as an electron donor to enhance the 16-ene-synthase activity of human P450 17A1. In this review, we discuss the many roles of cyt b5 and focus on the modulation of CYP17A1 activities by cyt b5 and the mechanisms involved.
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Affiliation(s)
- Megh Raj Bhatt
- Everest Biotech Pvt. Ltd., Khumaltar, Lalitpur, P.O. Box 21608, Kathmandu 44600, Nepal
| | - Yogan Khatri
- Institute of Biochemistry, Saarland University, 66123 Saarbrücken, Germany
| | - Raymond J Rodgers
- School of Medicine, Robinson Research Institute, University of Adelaide, Adelaide SA 5005, Australia
| | - Lisandra L Martin
- School of Chemistry, Monash University, Clayton, 3800, Victoria, Australia.
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26
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Deo P, Sahu KK, Dhibar DP, Varma SC. Naphthalene ball poisoning: a rare cause of acquired methaemoglobinaemia. BMJ Case Rep 2016; 2016:bcr-2016-215102. [PMID: 27226127 DOI: 10.1136/bcr-2016-215102] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
A 15-year-old boy presented to emergency services with accidental naphthalene ball ingestion. Following consumption he developed methaemoglobinaemia, massive intravascular haemolysis and acute kidney injury. He had no history suggestive of congenital haemoglobin M disease. Development of severe methaemoglobinaemia and intravascular haemolysis is quite unusual after consumption of a single ball of naphthalene. The patient was managed with ascorbic acid and intravenous N-acetyl cysteine. He also required haemodialysis for acute kidney injury that developed secondary to pigment nephropathy.
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Affiliation(s)
- Prateek Deo
- Department of Internal Medicine, PGIMER, Chandigarh, India
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27
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Porter TD. Electron Transfer Pathways in Cholesterol Synthesis. Lipids 2015; 50:927-36. [PMID: 26344922 DOI: 10.1007/s11745-015-4065-1] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2015] [Accepted: 08/21/2015] [Indexed: 12/17/2022]
Abstract
Cholesterol synthesis in the endoplasmic reticulum requires electron input at multiple steps and utilizes both NADH and NADPH as the electron source. Four enzymes catalyzing five steps in the pathway require electron input: squalene monooxygenase, lanosterol demethylase, sterol 4α-methyl oxidase, and sterol C5-desaturase. The electron-donor proteins for these enzymes include cytochrome P450 reductase and the cytochrome b5 pathway. Here I review the evidence for electron donor protein requirements with these enzymes, the evidence for additional electron donor pathways, and the effect of deletion of these redox enzymes on cholesterol and lipid metabolism.
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Affiliation(s)
- Todd D Porter
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, Lexington, KY, 40536-0596, USA.
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28
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Storbeck KH, Swart AC, Fox CL, Swart P. Cytochrome b5 modulates multiple reactions in steroidogenesis by diverse mechanisms. J Steroid Biochem Mol Biol 2015; 151:66-73. [PMID: 25446886 DOI: 10.1016/j.jsbmb.2014.11.024] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/14/2014] [Revised: 11/02/2014] [Accepted: 11/21/2014] [Indexed: 12/18/2022]
Abstract
Cytochrome b5 (cyt-b5) is a relatively small haemoprotein which plays an important role in the regulation of mammalian steroidogenesis. This unique protein has the ability to modulate the activity of key steroidogenic enzymes via a number of diverse reaction mechanisms. Cyt-b5 can augment the 17,20-lyase activity of CYP17A1 by promoting the interaction of CYP17A1 and POR; enhance the 16-ene-synthase activity of CYP17A1 by acting as an electron donor; and enhance the activity of 3βHSD by increasing the affinity of 3βHSD for its cofactor NAD(+). We review the modulation of CYP17A1 and 3βHSD activity by cyt-b5 and discuss the reaction mechanisms associated with each activity. The physiological importance of cyt-b5 in regulating mammalian steroidogenesis is presented and the impact of inactivating cyt-b5 mutations are reviewed. This article is part of a Special Issue entitled 'Steroid/Sterol signaling'.
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Affiliation(s)
- Karl-Heinz Storbeck
- Department of Biochemistry, University of Stellenbosch, Stellenbosch 7600, South Africa
| | - Amanda C Swart
- Department of Biochemistry, University of Stellenbosch, Stellenbosch 7600, South Africa
| | - Cheryl L Fox
- Department of Biochemistry, University of Stellenbosch, Stellenbosch 7600, South Africa
| | - Pieter Swart
- Department of Biochemistry, University of Stellenbosch, Stellenbosch 7600, South Africa.
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29
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Kudale S, Sethi SK, Dhaliwal M, Kher V. Methemoglobinemia due to quinine causing severe acute kidney injury in a child. Indian J Nephrol 2014; 24:394-6. [PMID: 25484537 PMCID: PMC4244723 DOI: 10.4103/0971-4065.134681] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022] Open
Abstract
Congenital methemoglobinemia is a rare condition resulting from a deficiency of nicotinamide adenine dinucleotide-cytochrome b5 reductase. Acquired methemoglobinemia may result due to certain drugs, chemicals and food items. Information on epidemiological determinants from India is sparse. This report describes methemoglobinemia in a 4-year-old child after parenteral administration of quinine causing acute kidney injury. This case emphasizes the need of awareness of potential adverse events of antimalarial drugs. Prompt management of methemoglobinemia is essential to avoid potential life-threatening complications.
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Affiliation(s)
- S Kudale
- Department of Pediatrics, The Medicity Hospital, Gurgaon, Haryana, India
| | - S K Sethi
- Kidney Institute, Medanta, The Medicity Hospital, Gurgaon, Haryana, India
| | - M Dhaliwal
- Department of Pediatric Intensive Care, The Medicity Hospital, Gurgaon, Haryana, India
| | - V Kher
- Kidney Institute, Medanta, The Medicity Hospital, Gurgaon, Haryana, India
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30
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Blanke KL, Sacco JC, Millikan RC, Olshan AF, Luo J, Trepanier LA. Polymorphisms in the carcinogen detoxification genes CYB5A and CYB5R3 and breast cancer risk in African American women. Cancer Causes Control 2014; 25:1513-21. [PMID: 25225034 PMCID: PMC4216608 DOI: 10.1007/s10552-014-0454-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2013] [Accepted: 07/31/2014] [Indexed: 11/29/2022]
Abstract
PURPOSE Cytochrome b 5 (encoded by CYB5A) and NADH cytochrome b 5 reductase (encoded by CYB5R3) detoxify aromatic and heterocyclic amine mammary carcinogens found in cigarette smoke. We hypothesized that CYB5A and CYB5R3 polymorphisms would be associated with breast cancer risk in women. METHODS We characterized the prevalence of 18 CYB5A and CYB5R3 variants in genomic DNA from African American (AfrAm) and Caucasian (Cauc) women from the Carolina Breast Cancer Study population (1,946 cases and 1,747 controls) and determined their associations with breast cancer risk, with effect modification by smoking. RESULTS A CYB5R3 variant, I1M+6T (rs8190370), was significantly more common in breast cancer cases (MAF 0.0238) compared with controls (0.0169, p = 0.039); this was attributable to a higher MAF in AfrAm cases (0.0611) compared with AfrAm controls (0.0441, p = 0.046; adjusted OR 1.41, CI 0.98-2.04; p = 0.062). When smoking was considered, I1M+6T was more strongly associated with breast cancer risk in AfrAm smokers (adjusted OR 2.10, 1.08-4.07; p = 0.028) compared with never smokers (OR = 1.21; 0.77-1.88; p for interaction = 0.176). I1M+6T and three additional CYB5R3 variants, -251T, I8-1676C, and *392C, as well as two CYB5A variants, 13G and I2-992T, were significantly more common in AfrAms compared with Caucs. CONCLUSIONS CYB5R3 I1M+6C>T should be considered in future molecular epidemiologic studies of breast cancer risk in AfrAms. Further, variants in CYB5A and CYB5R3 should be considered in the evaluation of other tumors in AfrAms that are associated with aromatic and heterocyclic amine exposures, to include prostate, bladder, and colon cancers.
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Affiliation(s)
- Kristina L. Blanke
- Department of Medical Sciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, WI
| | - James C. Sacco
- Department of Medical Sciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, WI
| | - Robert C. Millikan
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, NC
- Lineberger Comprehensive Cancer Center, School of Medicine, University of North Carolina, Chapel Hill, NC
| | - Andrew F. Olshan
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, NC
- Lineberger Comprehensive Cancer Center, School of Medicine, University of North Carolina, Chapel Hill, NC
| | - Jingchun Luo
- Lineberger Comprehensive Cancer Center, School of Medicine, University of North Carolina, Chapel Hill, NC
| | - Lauren A. Trepanier
- Department of Medical Sciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, WI
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Regulation of cytochrome b5 expression by miR-223 in human liver: effects on cytochrome P450 activities. Pharm Res 2014; 31:780-94. [PMID: 24078287 DOI: 10.1007/s11095-013-1200-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2013] [Accepted: 08/31/2013] [Indexed: 01/24/2023]
Abstract
PURPOSE Cytochrome b5 (b5) is a hemoprotein that transfers electrons to several enzymes to fulfill functions in fatty acid desaturation, methemoglobin reduction, steroidogenesis, and drug metabolism. Despite the importance of b5, the regulation of b5 expression in human liver remains largely unknown. We investigated whether microRNA (miRNA) might be involved in the regulation of human b5. METHODS Twenty-four human liver specimens were used for correlation analysis. In silico analysis and luciferase assay were performed to determine whether the predicted miRNAs functionally target to b5. The miR-223 was overexpressed into HepG2 cells infected with adenovirus expressing human cytochrome P450. RESULTS In human livers, the b5 protein levels were not positively correlated with the b5 mRNA levels, and miR-223 levels were inversely correlated with the b5 mRNA levels or the translational efficiencies. The luciferase assay showed that miR-223 functionally binds to the element in the 3′-untranslated region of b5 mRNA. The overexpression of miR-223 significantly reduced the endogenous b5 protein level and the mRNA stability in HepG2 cells. Moreover, the overexpression of miR-223 significantly reduced CYP3A4-catalyzed testosterone 6β-hydroxylation activity and CYP2E1-catalyzed chlorzoxazone 6-hydroxylase activity but not CYP1A2-catalyzed 7-ethoxyresorufin O-deethylase activity. CONCLUSIONS miR-223 down-regulates b5 expression in the human liver, modulating P450 activities.
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Kandel SE, Lampe JN. Role of protein-protein interactions in cytochrome P450-mediated drug metabolism and toxicity. Chem Res Toxicol 2014; 27:1474-86. [PMID: 25133307 PMCID: PMC4164225 DOI: 10.1021/tx500203s] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
![]()
Through their unique oxidative chemistry,
cytochrome P450 monooxygenases
(CYPs) catalyze the elimination of most drugs and toxins from the
human body. Protein–protein interactions play a critical role
in this process. Historically, the study of CYP–protein interactions
has focused on their electron transfer partners and allosteric mediators,
cytochrome P450 reductase and cytochrome b5. However, CYPs can bind
other proteins that also affect CYP function. Some examples include
the progesterone receptor membrane component 1, damage resistance
protein 1, human and bovine serum albumin, and intestinal fatty acid
binding protein, in addition to other CYP isoforms. Furthermore, disruption
of these interactions can lead to altered paths of metabolism and
the production of toxic metabolites. In this review, we summarize
the available evidence for CYP protein–protein interactions
from the literature and offer a discussion of the potential impact
of future studies aimed at characterizing noncanonical protein–protein
interactions with CYP enzymes.
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Affiliation(s)
- Sylvie E Kandel
- XenoTech, LLC , 16825 West 116th Street, Lenexa, Kansas 66219, United States
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McKenna JA, Sacco J, Son TT, Trepanier LA, Callan MB, Harvey JW, Arndt JW. Congenital methemoglobinemia in a dog with a promoter deletion and a nonsynonymous coding variant in the gene encoding cytochrome b₅. J Vet Intern Med 2014; 28:1626-31. [PMID: 25145387 PMCID: PMC4895586 DOI: 10.1111/jvim.12423] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2013] [Revised: 05/01/2014] [Accepted: 06/23/2014] [Indexed: 12/31/2022] Open
Affiliation(s)
- J A McKenna
- Department of Emergency and Critical Care, Advanced Critical Care, Emergency & Specialty Services - Los Angeles, Culver City, CA
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Giovannetti E, Wang Q, Avan A, Funel N, Lagerweij T, Lee JH, Caretti V, van der Velde A, Boggi U, Wang Y, Vasile E, Peters GJ, Wurdinger T, Giaccone G. Role of CYB5A in pancreatic cancer prognosis and autophagy modulation. J Natl Cancer Inst 2013; 106:djt346. [PMID: 24301457 DOI: 10.1093/jnci/djt346] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND Loss of 18q22.3 is a prognostic marker in pancreatic ductal adenocarcinoma (PDAC). This study investigated genes encoded by this cytoband. METHODS We studied mRNA/protein expression in radically resected (n = 130) and metastatic patients (n = 50). The role of CYB5A was tested in 11 PDAC cell lines and five primary cultures through retrovirus-mediated upregulation and small interfering RNA using wound-healing, invasion, annexin-V, electron microscopy, and autophagic assays, as well as autophagy genes and kinases arrays. CYB5A+ orthotopic models (n = 6 mice/group) were monitored by Firefly and Gaussia-luciferase bioluminescence, magnetic resonance imaging, and high-frequency ultrasound. Data were analyzed by t test, Fisher exact-test, log-rank test and Cox proportional hazards models. All statistical tests were two-sided. RESULTS Both resected and metastatic patients with low mRNA or protein expression of CYB5A had statistically significantly shorter survival (eg, median = 16.7 months, 95% confidence interval [CI] = 13.5 to 19.9; vs median = 24.8 months, 95% CI = 12.8 to 36.9; P = .02, two-sided log-rank test; n = 82 radically resected PDACs), and multivariable analyses confirmed prognostic relevance. Moreover, we characterized a novel function to CYB5A, autophagy induction, concomitant with reduced proliferation and migration/invasion of PDAC cells. Network analysis of proautophagic pathways suggested CYB5A interaction with TRAF6, which was confirmed by TRAF6 downregulation after CYB5A reconstitution (-69% in SU.86.86-CYB5A+; P = .005, two-sided t test). CYB5A silencing had opposite effects, restoring TRAF6 expression and wound healing. In vivo studies showed that CYB5A induced autophagy while inhibiting tumor growth/metastasis and increasing survival (median = 57 days, 95% CI = 52 to 61; vs median = 44 days, 95% CI = 21 to 57; P = .03, two-sided log-rank test). CONCLUSIONS These results define CYB5A as a novel prognostic factor for PDAC that exerts its tumor-suppressor function through autophagy induction and TRAF6 modulation.
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Affiliation(s)
- Elisa Giovannetti
- Affiliations of authors: Department of Medical Oncology (EG, AA, GJP) and Department of Neurosurgery (TL, VC, TW), VU University Medical Center, and Centre for Integrative Bioinformatics (AvdV), VU University, Amsterdam, the Netherlands; Department of Ricerca Traslazionale e delle Nuove Tecnologie in Medicina e Chirurgia, University of Pisa, Pisa, Italy (NF, UB, EV); Department of Neurology, Stanford University, Stanford, CA (VC); Department of Neurology, Massachusetts General Hospital and Neuroscience Program, Harvard Medical School, Boston, MA (TW); Medical Oncology Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD (QW, J-HL, YW, GG)
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Functional and structural characterisation of a viral cytochrome b5. FEBS Lett 2013; 587:3633-9. [PMID: 24100138 DOI: 10.1016/j.febslet.2013.09.035] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2013] [Revised: 09/19/2013] [Accepted: 09/19/2013] [Indexed: 11/21/2022]
Abstract
Cytochrome b5 is a ubiquitous electron transport protein. The sequenced viral OtV-2 genome, which infects Ostreococcus tauri, was predicted to encode a putative cytochrome b5 enzyme. Using purified OtV-2 cytochrome b5 we confirm this protein has identical spectral properties to purified human cytochrome b5 and additionally that the viral enzyme can substitute for yeast cytochrome b5 in yeast cytochrome P450 51 mediated sterol 14α-demethylation. The crystal structure of the OtV-2 cytochrome b5 enzyme reveals a single domain, comprising four β sheets, four α helices and a haem moiety, which is similar to that found in larger eukaryotic cytochrome proteins. As a product of a horizontal gene transfer event involving a subdomain of the host fumarate reductase-like protein, OtV-2 cytochrome b5 appears to have diverged in function and is likely to have evolved an entirely new role for the virus during infection. Indeed, lacking a hydrophobic C-terminal anchor, OtV-2 encodes the first cytosolic cytochrome b5 characterised. The lack of requirement for membrane attachment (in contrast to all other microsomal cytochrome b5s) may be a reflection of the small size of the host cell, further emphasizes the unique nature of this virus gene product and draws attention to the potential importance of cytochrome b5 metabolic activity at the extremes of cellular scale.
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Storbeck KH, Swart AC, Goosen P, Swart P. Cytochrome b5: novel roles in steroidogenesis. Mol Cell Endocrinol 2013; 371:87-99. [PMID: 23228600 DOI: 10.1016/j.mce.2012.11.020] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/17/2012] [Revised: 11/20/2012] [Accepted: 11/20/2012] [Indexed: 11/25/2022]
Abstract
Cytochrome b(5) (cyt-b(5)) is essential for the regulation of steroidogenesis and as such has been implicated in a number of clinical conditions. It is well documented that this small hemoprotein augments the 17,20-lyase activity of cytochrome P450 17α-hydroxylase/17,20-lyase (CYP17A1). Studies have revealed that this augmentation is accomplished by cyt-b(5) enhancing the interaction between cytochrome P450 reductase (POR) and CYP17A1. In this paper we present evidence that cyt-b(5) induces a conformational change in CYP17A1, in addition to facilitating the interaction between CYP17A1 and POR. We also review the recently published finding that cyt-b(5) allosterically augments the activity of 3β-hydroxysteroid dehydrogenase/Δ(5)-Δ(4) isomerase (3βHSD), a non cytochrome P450 enzyme, by increasing the enzymes affinity for its cofactor, NAD(+). The physiological importance of this finding, in terms of understanding adrenal androstenedione production, is examined. Finally, evidence that cyt-b(5) is able to form homomeric complexes in living cells is presented and discussed.
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Affiliation(s)
- Karl-Heinz Storbeck
- Department of Biochemistry, University of Stellenbosch, Stellenbosch 7602, South Africa
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Evaluation of polymorphisms in the sulfonamide detoxification genes NAT2, CYB5A, and CYB5R3 in patients with sulfonamide hypersensitivity. Pharmacogenet Genomics 2013; 22:733-40. [PMID: 22850190 DOI: 10.1097/fpc.0b013e328357a735] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
OBJECTIVE To determine whether polymorphisms in the sulfonamide detoxification genes, CYB5A (encoding cytochrome b(5)), CYB5R3 (encoding cytochrome b(5) reductase), or NAT2 (encoding N-acetyltransferase 2) were over-represented in patients with delayed sulfonamide drug hypersensitivity, compared with control patients who tolerated a therapeutic course of trimethoprim-sulfamethoxazole without adverse event. METHODS DNA from 99 nonimmunocompromised patients with sulfonamide hypersensitivity who were identified from the Personalized Medicine Research Project at the Marshfield Clinic, and from 99 age-matched, race-matched, and sex-matched drug-tolerant controls, were genotyped for four CYB5A and five CYB5R3 polymorphisms, and for all coding NAT2 SNPs. RESULTS CYB5A and CYB5R3 SNPs were found at low allele frequencies (<3-4%), which did not differ between hypersensitive and tolerant patients. NAT2 allele and haplotype frequencies, as well as inferred NAT2 phenotypes, also did not differ between groups (60 vs. 59% slow acetylators). Finally, no difference in NAT2 status was found in a subset of patients with more severe hypersensitivity signs (drug reaction with eosinophilia and systemic symptoms) compared with tolerant patients. CONCLUSION We found no evidence of a substantial involvement of these nine CYB5A or CYB5R3 polymorphisms in sulfonamide hypersensitivity risk, although minor effects cannot be completely ruled out. Despite careful medical record review and full resequencing of the NAT2 coding region, we found no association of NAT2 coding alleles with sulfonamide hypersensitivity (predominantly cutaneous eruptions) in this adult Caucasian population.
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Peng HM, Auchus RJ. The action of cytochrome b(5) on CYP2E1 and CYP2C19 activities requires anionic residues D58 and D65. Biochemistry 2012. [PMID: 23193974 DOI: 10.1021/bi301384n] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The capacity of cytochrome b(5) (b(5)) to influence cytochrome P450 activities has been extensively studied and physiologically validated. Apo-b(5) enhances the activities of CYP3A4, CYP2A6, CYP2C19, and CYP17A1 but not that of CYP2E1 or CYP2D6, suggesting that the b(5) interaction varies among P450s. We previously showed that b(5) residues E48 and E49 are required to stimulate the 17,20-lyase activity of CYP17A1, but these same residues might not mediate b(5) activation of other P450 reactions, such as CYP2E1-catalyzed oxygenations, which are insensitive to apo-b(5). Using purified P450, b(5), and reductase (POR) in reconstituted assays, the D58G/D65G double mutation, of residues located in a hydrophilic α-helix of b(5), totally abolished the ability to stimulate CYP2E1-catalyzed chlorzoxazone 6-hydroxylation. In sharp contrast, the D58G/D65G double mutation retained the full ability to stimulate the 17,20-lyase activity of CYP17A1. The D58G/D65G double mutation competes poorly with wild-type b(5) for binding to the CYP2E1·POR complex yet accepts electrons from POR at a similar rate. Furthermore, the phospholipid composition markedly influences P450 turnover and b(5) stimulation and specificity, particularly for CYP17A1, in the following order: phosphatidylserine > phosphatidylethanolamine > phosphatidylcholine. The D58G/D65G double mutation also failed to stimulate CYP2C19-catalyzed (S)-mephenytoin 4-hydroxylation, whereas the E48G/E49G double mutation stimulated these activities of CYP2C19 and CYP2E1 equivalent to wild-type b(5). We conclude that b(5) residues D58 and D65 are essential for the stimulation of CYP2E1 and CYP2C19 activities and that the phospholipid composition significantly influences the b(5)-P450 interaction. At least two surfaces of b(5) differentially influence P450 activities, and the critical residues for individual P450 reactions cannot be predicted from sensitivity to apo-b(5) alone.
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Affiliation(s)
- Hwei-Ming Peng
- Division of Metabolism, Endocrinology, and Diabetes, Department of Internal Medicine, University of Michigan, Ann Arbor, MI 48109, USA
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Idkowiak J, Randell T, Dhir V, Patel P, Shackleton CHL, Taylor NF, Krone N, Arlt W. A missense mutation in the human cytochrome b5 gene causes 46,XY disorder of sex development due to true isolated 17,20 lyase deficiency. J Clin Endocrinol Metab 2012; 97:E465-75. [PMID: 22170710 PMCID: PMC3388247 DOI: 10.1210/jc.2011-2413] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/26/2011] [Accepted: 11/11/2011] [Indexed: 11/29/2022]
Abstract
CONTEXT Isolated 17,20 lyase deficiency is commonly defined by apparently normal 17α-hydroxylase activity but severely reduced 17,20 lyase activity of the bifunctional enzyme cytochrome P450 (CYP) enzyme 17A1 (CYP17A1), resulting in sex steroid deficiency but normal glucocorticoid and mineralocorticoid reserve. Cytochrome b5 (CYB5A) is thought to selectively enhance 17,20 lyase activity by facilitating the allosteric interaction of CYP17A1 with its electron donor P450 oxidoreductase (POR). OBJECTIVE We investigated a large consanguineous family including three siblings with 46,XY disorder of sex development (DSD) presenting with isolated 17,20 lyase deficiency. DESIGN We investigated the clinical and biochemical phenotype, conducted genetic analyses, and functionally characterized the identified CYB5A mutation in cell-based CYP17A1 coexpression assays. RESULTS All three siblings presented with 46,XY DSD, sex steroid deficiency, normal mineralocorticoids and glucocorticoids, and a urine steroid metabolome suggestive of isolated 17,20 lyase deficiency. CYP17A1 and POR sequences were normal, but we detected a homozygous CYB5A missense mutation (g.28,400A→T; p.H44L). Functional in vitro analysis revealed normal CYP17A1 17α-hydroxylase activity but severely impaired 17,20 lyase activity. In silico analysis suggested the disruption of CYB5A heme binding by p.H44L. CONCLUSION We have identified the first human CYB5A missense mutation as the cause of isolated 17,20 lyase deficiency in three individuals with 46,XY DSD. Detailed review of previously reported cases with apparently isolated 17,20 lyase deficiency due to mutant CYP17A1 and POR reveals impaired 17α-hydroxylase activity as assessed by steroid metabolome analysis and short cosyntropin testing. This suggests that truly isolated 17,20 lyase deficiency is observed only in individuals with inactivating CYB5A mutations.
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Affiliation(s)
- Jan Idkowiak
- Centre for Endocrinology, Diabetes, and Metabolism, School of Clinical and Experimental Medicine, University of Birmingham, Birmingham B15 2TT, United Kingdom
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Abstract
CONTEXT Disorders of steroidogenesis have been instrumental in delineating human steroidogenic pathways. Each genetic disorder seemed to correspond to a different steroidogenic activity, helping to identify several enzymes. Beginning in 1972, several patients have been reported as having "17,20 lyase deficiency," but there have been inconsistent genetic findings. OBJECTIVE This manuscript reviews the biochemistry, genetics, and clinical disorders of 17,20 lyase activity, which converts 21-carbon precursors of glucocorticoids to 19-carbon precursors of sex steroids. FINDINGS A single enzyme, cytochrome P450c17, catalyzes both 17α-hydroxylase activity and 17,20 lyase activity. The 17,20 lyase activity is especially sensitive to the activities of the accessory proteins P450 oxidoreductase and cytochrome b(5). The first cases of genetically and biochemically proven 17,20 lyase deficiency were reported in 1997, in which specific P450c17 mutations were identified that lost 17,20 lyase activity but not 17α-hydroxylase activity when assayed in vitro. Subsequent work identified other P450c17 mutations and mutations in the genes encoding P450 oxidoreductase and cytochrome b(5). Recently, the initially reported cases from 1972 were found to carry mutations in two aldo-keto reductases, AKR1C2 and AKR1C4. These AKR1C isozymes catalyze 3α-hydroxysteroid dehydrogenase activity in the so-called "backdoor pathway" by which the fetal testis produces dihydrotestosterone without the intermediacy of testosterone. CONCLUSIONS 17,20 Lyase deficiency should be considered a syndrome with multiple causes, and not a single disease. Study of this very rare disorder has substantially advanced our understanding of the pathways, mechanisms, and control of androgen synthesis. Mutations in other, as-yet unidentified genes may also cause this phenotype.
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Affiliation(s)
- Walter L Miller
- Department of Pediatrics, University of California, San Francisco, San Francisco, California 94143-0978, USA.
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Regulation of hemocytes in Drosophila requires dappled cytochrome b5. Biochem Genet 2011; 49:329-51. [PMID: 21279680 PMCID: PMC3092937 DOI: 10.1007/s10528-010-9411-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2010] [Accepted: 12/20/2010] [Indexed: 12/12/2022]
Abstract
A major category of mutant hematopoietic phenotypes in Drosophila is melanotic tumors or nodules, which consist of abnormal and overproliferated blood cells, similar to granulomas. Our analyses of the melanotic mutant dappled have revealed a novel type of gene involved in blood cell regulation. The dappled gene is an essential gene that encodes cytochrome b5, a conserved hemoprotein that participates in electron transfer in multiple biochemical reactions and pathways. Viable mutations of dappled cause melanotic nodules and hemocyte misregulation during both hematopoietic waves of development. The sexes are similarly affected, but hemocyte number is different in females and males of both mutants and wild type. Additionally, initial tests show that curcumin enhances the dappled melanotic phenotype and establish screening of endogenous and xenobiotic compounds as a route for analysis of cytochrome b5 function. Overall, dappled provides a tractable genetic model for cytochrome b5, which has been difficult to study in higher organisms.
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The interaction of microsomal cytochrome P450 2B4 with its redox partners, cytochrome P450 reductase and cytochrome b(5). Arch Biochem Biophys 2010; 507:144-53. [PMID: 21055385 DOI: 10.1016/j.abb.2010.10.023] [Citation(s) in RCA: 101] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2010] [Revised: 10/27/2010] [Accepted: 10/28/2010] [Indexed: 11/21/2022]
Abstract
Cytochrome P450 2B4 is a microsomal protein with a multi-step reaction cycle similar to that observed in the majority of other cytochromes P450. The cytochrome P450 2B4-substrate complex is reduced from the ferric to the ferrous form by cytochrome P450 reductase. After binding oxygen, the oxyferrous protein accepts a second electron which is provided by either cytochrome P450 reductase or cytochrome b(5). In both instances, product formation occurs. When the second electron is donated by cytochrome b(5), catalysis (product formation) is ∼10- to 100-fold faster than in the presence of cytochrome P450 reductase. This allows less time for side product formation (hydrogen peroxide and superoxide) and improves by ∼15% the coupling of NADPH consumption to product formation. Cytochrome b(5) has also been shown to compete with cytochrome P450 reductase for a binding site on the proximal surface of cytochrome P450 2B4. These two different effects of cytochrome b(5) on cytochrome P450 2B4 reactivity can explain how cytochrome b(5) is able to stimulate, inhibit, or have no effect on cytochrome P450 2B4 activity. At low molar ratios (<1) of cytochrome b(5) to cytochrome P450 reductase, the more rapid catalysis results in enhanced substrate metabolism. In contrast, at high molar ratios (>1) of cytochrome b(5) to cytochrome P450 reductase, cytochrome b(5) inhibits activity by binding to the proximal surface of cytochrome P450 and preventing the reductase from reducing ferric cytochrome P450 to the ferrous protein, thereby aborting the catalytic reaction cycle. When the stimulatory and inhibitory effects of cytochrome b(5) are equal, it will appear to have no effect on the enzymatic activity. It is hypothesized that cytochrome b(5) stimulates catalysis by causing a conformational change in the active site, which allows the active oxidizing oxyferryl species of cytochrome P450 to be formed more rapidly than in the presence of reductase.
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Abstract
In the biosynthesis of steroid hormones the neutral lipid cholesterol, a normal constituent of lipid bilayers is transformed via a series of hydroxylation, oxidation, and reduction steps into a vast array of biologically active compounds: mineralocorticoids, glucocorticoids, and sex hormones. Glucocorticoids regulate many aspects of metabolism and immune function, whereas mineralocorticoids help maintain blood volume and control renal excretion of electrolytes. Sex hormones are essential for sex differentiation in male and support reproduction. They include androgens, estrogens, and progestins. A block in the pathway of steroid biosynthesis leads to the lack of hormones downstream and accumulation of the upstream compounds that can activate other members of the steroid receptor family. This review deals with the clinical consequences of these blocks.
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Affiliation(s)
- A Biason-Lauber
- University Children's Hospital, Division of Endocrinology and Diabetology, Steinwiesstrasse 75, CH-8032 Zurich, Switzerland.
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Finn RD, McLaughlin LA, Hughes C, Song C, Henderson CJ, Roland Wolf C. Cytochrome b5 null mouse: a new model for studying inherited skin disorders and the role of unsaturated fatty acids in normal homeostasis. Transgenic Res 2010; 20:491-502. [PMID: 20676935 PMCID: PMC3090575 DOI: 10.1007/s11248-010-9426-1] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2010] [Accepted: 07/03/2010] [Indexed: 01/25/2023]
Abstract
Microsomal cytochrome b (5) is a ubiquitous, 15.2 kDa haemoprotein implicated in a number of cellular processes such as fatty acid desaturation, drug metabolism, steroid hormone biosynthesis and methaemoglobin reduction. As a consequence of these functions this protein has been considered essential for life. Most of the ascribed functions of cytochrome b (5), however, stem from in vitro studies and for this reason we have carried out a germline deletion of this enzyme. We have unexpectedly found that cytochrome b (5) null mice were viable and fertile, with pups being born at expected Mendelian ratios. However, a number of intriguing phenotypes were identified, including altered drug metabolism, methaemoglobinemia and disrupted steroid hormone homeostasis. In addition to these previously identified roles for this protein, cytochrome b (5) null mice displayed skin defects closely resembling those observed in autosomal recessive congenital ichthyosis and retardation of neonatal development, indicating that this protein, possibly as a consequence of its role in the de novo biosynthesis of unsaturated fatty acids, plays a central role in skin development and neonatal nutrition. Results from fatty acid profile analysis of several tissues suggest that cytochrome b (5) plays a role controlling saturated/unsaturated homeostasis. These data demonstrate that regional concentrations of unsaturated fatty acids are controlled by endogenous metabolic pathways and not by diet alone.
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Affiliation(s)
- Robert D. Finn
- Present Address: School of Applied Sciences, Ellison Building, Northumbria University, Newcastle, NE1 8ST UK
| | - Lesley A. McLaughlin
- Cancer Research UK Molecular Pharmacology Unit, Biomedical Research Institute, Level 5, Ninewells Hospital & Medical School, Dundee, DD1 9SY UK
| | - Catherine Hughes
- Cancer Research UK Molecular Pharmacology Unit, Biomedical Research Institute, Level 5, Ninewells Hospital & Medical School, Dundee, DD1 9SY UK
| | - Chengli Song
- School of Medical Instrument and Food Engineering, University of Shanghai for Science and Technology, 200093 Shanghai, China
| | - Colin J. Henderson
- Cancer Research UK Molecular Pharmacology Unit, Biomedical Research Institute, Level 5, Ninewells Hospital & Medical School, Dundee, DD1 9SY UK
| | - C. Roland Wolf
- Cancer Research UK Molecular Pharmacology Unit, Biomedical Research Institute, Level 5, Ninewells Hospital & Medical School, Dundee, DD1 9SY UK
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Mendonca BB, Costa EMF, Belgorosky A, Rivarola MA, Domenice S. 46,XY DSD due to impaired androgen production. Best Pract Res Clin Endocrinol Metab 2010; 24:243-62. [PMID: 20541150 DOI: 10.1016/j.beem.2009.11.003] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Disorders of androgen production can occur in all steps of testosterone biosynthesis and secretion carried out by the foetal Leydig cells as well as in the conversion of testosterone into dihydrotestosterone (DHT). The differentiation of Leydig cells from mesenchymal cells is the first walk for testosterone production. In 46,XY disorders of sex development (DSDs) due to Leydig cell hypoplasia, there is a failure in intrauterine and postnatal virilisation due to the paucity of interstitial Leydig cells to secrete testosterone. Enzymatic defects which impair the normal synthesis of testosterone from cholesterol and the conversion of testosterone to its active metabolite DHT are other causes of DSD due to impaired androgen production. Mutations in the genes that codify the enzymes acting in the steps from cholesterol to DHT have been identified in affected patients. Patients with 46,XY DSD secondary to defects in androgen production show a variable phenotype, strongly depending of the specific mutated gene. Often, these conditions are detected at birth due to the ambiguity of external genitalia but, in several patients, the extremely undervirilised genitalia postpone the diagnosis until late childhood or even adulthood. These patients should receive long-term care provided by multidisciplinary teams with experience in this clinical management.
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Affiliation(s)
- Berenice B Mendonca
- Hospital das Clinicas, Faculdade de Medicina da Universidade de Sao Paulo, Sao Paulo, Brazil.
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Kok RC, Timmerman MA, Wolffenbuttel KP, Drop SLS, de Jong FH. Isolated 17,20-lyase deficiency due to the cytochrome b5 mutation W27X. J Clin Endocrinol Metab 2010; 95:994-9. [PMID: 20080843 DOI: 10.1210/jc.2008-1745] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
CONTEXT Cytochrome P450c17 (P450c17) is a bifunctional enzyme necessary for the production of glucocorticoids (17-hydroxylase activity) and sex steroids (17,20-lyase activity). Isolated 17,20-lyase deficiency is a rare condition characterized by a deficient production of androgens resulting in 46,XY disorders of sex development (DSD) while the production of glucocorticoids is intact. Several missense mutations in the CYP17A1 gene are known to cause this condition. Cytochrome b(5) (CytB5) is an important factor in 17,20-lyase activity, probably by acting as an allosteric factor. OBJECTIVE The aim of this study was to investigate the role of CytB5 in a patient with defective 17,20-lyase activity. SETTING We conducted the study in a pediatric outpatient clinic of a University Hospital. PATIENTS We studied a 46,XY DSD patient with 17,20-lyase deficiency without missense mutation in the CYP17A1 gene and his parents. MAIN OUTCOME MEASURES We sequenced the CYB5 gene and measured steroid hormone levels. RESULTS Analysis of the CYB5 gene in our patient revealed a homozygous W27X mutation, leading to the formation of a premature stop codon; his parents were both heterozygous carriers of this mutation. This mutation results in the absence of residues E48 and E49 of CytB5, which are necessary for an intact 17,20-lyase activity. CONCLUSION We demonstrated 17,20-lyase deficiency due to an aberrant CytB5. Our findings thus provide evidence for an alternative etiology for this disorder.
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Affiliation(s)
- Renée C Kok
- Endocrine Laboratory, Department of Internal Medicine, Erasmus Medical Centre, P.O. Box 2040, 3000 CA Rotterdam, The Netherlands
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Hashimoto M, Takamiya S, Yokota T, Nakajima Y, Yamakura F, Sugio S, Aoki T. Ascaris suum cytochrome b5, an adult-specific secretory protein reducing oxygen-avid ferric hemoglobin. Arch Biochem Biophys 2008; 471:42-9. [DOI: 10.1016/j.abb.2007.12.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2007] [Revised: 12/06/2007] [Accepted: 12/07/2007] [Indexed: 10/22/2022]
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Sobrado P, Goren MA, James D, Amundson CK, Fox BG. A Protein Structure Initiative approach to expression, purification, and in situ delivery of human cytochrome b5 to membrane vesicles. Protein Expr Purif 2007; 58:229-41. [PMID: 18226920 DOI: 10.1016/j.pep.2007.11.018] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2007] [Revised: 11/26/2007] [Accepted: 11/30/2007] [Indexed: 11/18/2022]
Abstract
A specialized vector backbone from the Protein Structure Initiative was used to express full-length human cytochrome b5 as a C-terminal fusion to His8-maltose binding protein in Escherichia coli. The fusion protein could be completely cleaved by tobacco etch virus protease, and a yield of approximately 18 mg of purified full-length human cytochrome b5 per liter of culture medium was obtained (2.3mg per g of wet weight bacterial cells). In situ proteolysis of the fusion protein in the presence of chemically defined synthetic liposomes allowed facile spontaneous delivery of the functional peripheral membrane protein into a defined membrane environment without prior exposure to detergents or other lipids. The utility of this approach as a delivery method for production and incorporation of monotopic (peripheral) membrane proteins is discussed.
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Affiliation(s)
- Pablo Sobrado
- Department of Biochemistry, College of Agricultural and Life Sciences, University of Wisconsin, Room 141B, 433 Babcock Drive, Madison, WI 53706, USA
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Noble MA, Girvan HM, Smith SJ, Smith WE, Murataliev M, Guzov VM, Feyereisen R, Munro AW. Analysis of the interactions of cytochrome b5 with flavocytochrome P450 BM3 and its domains. Drug Metab Rev 2007; 39:599-617. [PMID: 17786641 DOI: 10.1080/03602530701468458] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Interactions between a soluble form of microsomal cytochrome b(5) (b(5)) from Musca domestica (housefly) and Bacillus megaterium flavocytochrome P450 BM3 and its component reductase (CPR), heme (P450) and FAD/NADPH-binding (FAD) domains were analyzed by a combination of steady-state and stopped-flow kinetics methods, and optical spectroscopy techniques. The high affinity binding of b(5) to P450 BM3 induced a low-spin to high-spin transition in the P450 heme iron (K(d) for b(5) binding = 0.44 microM and 0.72 microM for the heme domain and intact flavocytochrome, respectively). The b(5) had modest inhibitory effects on steady-state turnover of P450 BM3 with fatty acids, and the ferrous-carbon monoxy P450 complex was substantially stabilized on binding b(5). Single turnover reduction of b(5) by BM3 using stopped-flow absorption spectroscopy (k(lim) = 116 s(-1)) was substantially faster than steady-state reduction of b(5) by P450 BM3 (or its CPR and FAD domains), indicating rate-limiting step(s) other than BM3 flavin-to-b(5) heme electron transfer in the steady-state reaction. Steady-state b(5) reduction by P450 BM3 was considerably accelerated at high ionic strength. Pre-reduction of P450 BM3 by NADPH decreased the k(lim) for b(5) reduction approximately 10-fold, and also resulted in a lag phase in steady-state b(5) reduction that was likely due to BM3 conformational perturbations sensitive to the reduction state of the flavocytochrome. Ferrous b(5) could not reduce the ferric P450 BM3 heme domain under anaerobic conditions, consistent with heme iron reduction potentials of the two proteins. However, rapid oxidation of both hemoproteins occurred on aeration of the ferrous protein mixture (and despite the much slower autoxidation rate of b(5) in isolation), consistent with electron transfer occurring from b(5) to the oxyferrous P450 BM3 in the complex. The results demonstrate that strong interactions occur between a eukaryotic b(5) and a model prokaryotic P450. Binding of b(5) perturbs BM3 heme iron spin-state equilibrium, as is seen in many physiologically relevant b(5) interactions with eukaryotic P450s. These results are consistent with the conservation of structure of P450s (particularly at the heme proximal face) between prokaryotes and eukaryotes, and may point to as yet undiscovered roles for b(5)-like proteins in the control of activities of certain prokaryotic P450s.
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Kurian JR, Longlais BJ, Trepanier LA. Discovery and characterization of a cytochrome b5 variant in humans with impaired hydroxylamine reduction capacity. Pharmacogenet Genomics 2007; 17:597-603. [PMID: 17622936 DOI: 10.1097/fpc.0b013e328011aaff] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVES We have shown that cytochrome b5 (cyt b5), along with its reductase, NADH cytochrome b5 reductase (b5R), is capable of direct xenobiotic biotransformation. We hypothesized that functionally significant genetic variability in cyt b5 could be found in healthy individuals. BASIC METHODS Cyt b5 cDNAs were prepared from peripheral blood mononuclear cells from 63 individuals. MAIN RESULTS One individual was heterozygous for a sequence variant in cyt b5 (A178G), with a predicted amino acid substitution of T60A. This variant, when expressed in Escherichia. coli, maintained a similar Vmax for the hydroxylamines of sulfamethoxazole, 4-aminobiphenyl, and 2-amino-l-methyl-6-phenylimidazo[4,5-b] pyridine (PhIP), compared with wild type cyt b5, with a modestly increased Km (2 to 3.5-fold) for each substrate. When expressed in a mammalian system (HeLa cells), however, T60A was associated with a 70% reduction in cyt b5 protein expression compared with wild type. mRNA expression for both isoforms were comparable in HeLa cells, and translation of these mRNAs in a rabbit reticulocyte lysate system with inhibited proteasomal machinery were also similar. Incubation of these translated enzymes with uninhibited rabbit reticulocyte lysate, however, indicated greater susceptibility of T60A to proteasomal degradation. CONCLUSIONS These data indicate that a naturally occurring variant in cyt b5, T60A, leads to modestly altered affinity for hydroxylamine substrates and dramatically reduced cyt b5 expression. Work is underway to determine the prevalence of this and other variants in cyt b5 or b5R in a larger population, and to determine the association of such variants with differences in hydroxylamine reduction in vivo.
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Affiliation(s)
- Joseph R Kurian
- Department of Medical Sciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, WI 53706, USA
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