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Luo H, Li Y, Xie J, Xu C, Zhang Z, Li M, Xia B, Shi Z, Lin L. Effect and mechanism of Prunella vulgaris L. extract on alleviating lipopolysaccharide-induced acute mastitis in protecting the blood-milk barrier and reducing inflammation. JOURNAL OF ETHNOPHARMACOLOGY 2024; 328:117998. [PMID: 38484956 DOI: 10.1016/j.jep.2024.117998] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2023] [Revised: 02/25/2024] [Accepted: 02/27/2024] [Indexed: 03/25/2024]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE According to ancient literature, Prunella vulgaris L. (P vulgaris) alleviates mastitis and has been used in China for many years; however, there are no relevant reports that confirm this or the mechanism of its efficacy. AIM OF THE STUDY To explore the anti-acute mastitis effect and potential mechanism of P vulgaris extract. MATERIALS AND METHODS First, the active ingredients and targets of P vulgaris against mastitis were predicted using network pharmacology. Next, the relevant active ingredients were enriched using macroporous resins and verified using UV and UPLC-Q-TOF-MS/MS. Lastly, a mouse model of acute mastitis was established by injecting lipopolysaccharides into the mammary gland and administering P vulgaris extract by oral gavage. The pathological changes in mammary tissue were observed by HE staining. Serum and tissue inflammatory factors were measured by ELISA method. MPO activity in mammary tissue was measured using colorimetry and MPO expression was detected by immunohistochemistry. The expression of tight junction proteins (ZO-1, claudin-3, and occludin) in mammary tissue was detected by immunofluorescence and Western blot. iNOS and COX-2 in mammary tissue were detected by Western blot. MAPK pathway and NF-κB pathway related proteins were also detected by Western blot. RESULTS Network pharmacology predicted that phenolic acids and flavonoids in P vulgaris had anti-mastitis effects. The contents of total flavonoids and total phenolic acids in P vulgaris extract were 64.5% and 29.4%, respectively. UPLC-Q-TOF-MS/MS confirmed that P vulgaris extract contained phenolic acids and flavonoids. The results of animal experiments showed that P vulgaris extract reduced lipopolysaccharide-induced inflammatory edema, inflammatory cell infiltration, and interstitial congestion of mammary tissue. It also reduced the levels of serum and tissue inflammatory factors TNF-α, IL-6, and IL-1β, and inhibited the activation of MPO. Furthermore, it downregulated the expression of MAPK and NF-κB pathway-related proteins. The expressions of ZO-1, occludin, and claudin-3 in mammary gland tissues were upregulated. CONCLUSIONS P vulgaris extract can maintain the integrity of mammary connective tissue and reduce its inflammatory response to prevent acute mastitis. Its mechanism probably involves regulating NF-κB and MAPK pathways.
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Affiliation(s)
- Hongshan Luo
- College of Pharmacy, Hunan University of Chinese Medicine, Changsha, 410208, China; Key Laboratory for Quality Evaluation of Bulk Herbs of Hunan Province, Hunan University of Chinese Medicine, Changsha, 410208, China.
| | - Yamei Li
- College of Pharmacy, Hunan University of Chinese Medicine, Changsha, 410208, China; Key Laboratory for Quality Evaluation of Bulk Herbs of Hunan Province, Hunan University of Chinese Medicine, Changsha, 410208, China.
| | - Jingchen Xie
- College of Pharmacy, Hunan University of Chinese Medicine, Changsha, 410208, China; Key Laboratory for Quality Evaluation of Bulk Herbs of Hunan Province, Hunan University of Chinese Medicine, Changsha, 410208, China.
| | - Chunfang Xu
- College of Pharmacy, Hunan University of Chinese Medicine, Changsha, 410208, China; Key Laboratory for Quality Evaluation of Bulk Herbs of Hunan Province, Hunan University of Chinese Medicine, Changsha, 410208, China.
| | - Zhimin Zhang
- College of Pharmacy, Hunan University of Chinese Medicine, Changsha, 410208, China; Key Laboratory for Quality Evaluation of Bulk Herbs of Hunan Province, Hunan University of Chinese Medicine, Changsha, 410208, China.
| | - Minjie Li
- College of Pharmacy, Hunan University of Chinese Medicine, Changsha, 410208, China; Key Laboratory for Quality Evaluation of Bulk Herbs of Hunan Province, Hunan University of Chinese Medicine, Changsha, 410208, China.
| | - Bohou Xia
- College of Pharmacy, Hunan University of Chinese Medicine, Changsha, 410208, China; Key Laboratory for Quality Evaluation of Bulk Herbs of Hunan Province, Hunan University of Chinese Medicine, Changsha, 410208, China.
| | - Zhe Shi
- College of Pharmacy, Hunan University of Chinese Medicine, Changsha, 410208, China; Key Laboratory for Quality Evaluation of Bulk Herbs of Hunan Province, Hunan University of Chinese Medicine, Changsha, 410208, China.
| | - Limei Lin
- College of Pharmacy, Hunan University of Chinese Medicine, Changsha, 410208, China; Key Laboratory for Quality Evaluation of Bulk Herbs of Hunan Province, Hunan University of Chinese Medicine, Changsha, 410208, China.
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Chai J, Sun Z, Zhou Q, Xu J. Evaluation of Trace Elements Levels and Construction of Auxiliary Prediction Model in Patients with Diabetes Ketoacidosis in Type 1 Diabetes. Diabetes Metab Syndr Obes 2023; 16:3403-3415. [PMID: 37929055 PMCID: PMC10624197 DOI: 10.2147/dmso.s425156] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/21/2023] [Accepted: 10/22/2023] [Indexed: 11/07/2023] Open
Abstract
Background Trace elements play an important role in reflecting physical metabolic status, but have been rarely evaluated in diabetes ketoacidosis (DKA). Since clinical biochemical parameters are the first-line diagnostic data mastered by clinical doctors and DKA has a rapid progression, it is crucial to fully utilize clinical data and combine innovative parameters to assist in assessing disease progression. The aim of this study was to evaluate the levels of trace elements in DKA patients, followed by construction of predictive models combined with the laboratory parameters. Methods A total of 96 T1D individuals (48 DKA patients) were collected from the First Hospital of Jilin University. Serum calcium (Ca), magnesium (Mg), zinc (Zn), copper (Cu), iron (Fe) and selenium (Se) were measured by Inductively Coupled Plasma Mass Spectrometry, and the data of biochemical parameters were collected from the laboratory information system. Training and validation sets were used to construct the model and examine the efficiency of the model. The lambda-mu-sigma method was used to evaluate the changes in the model prediction efficiency as the severity of the patient's condition increases. Results Lower levels of serum Mg, Ca and Zn, but higher levels of serum Fe, Cu and Se were found in DKA patients. Low levels of total protein (TP), Zn and high levels of lipase would be an efficient combination for the prediction of DKA (Area under curves for training set and validation set were 0.867 and 0.961, respectively). The examination test confirmed the clinical applicability of the constructed models. The increasing predictive efficiency of the model was found with NACP. Conclusion More severe oxidative stress in DKA led to further imbalance of trace elements. The combination of TP, lipase and Zn could predict DKA efficiently, which would benefit the early identification and prevention of DKA to improve prognosis.
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Affiliation(s)
- Jiatong Chai
- Department of Laboratory Medicine, First Hospital of Jilin University, Changchun, People’s Republic of China
| | - Zeyu Sun
- Department of Laboratory Medicine, First Hospital of Jilin University, Changchun, People’s Republic of China
| | - Qi Zhou
- Department of Pediatrics, First Hospital of Jilin University, Changchun, People’s Republic of China
| | - Jiancheng Xu
- Department of Laboratory Medicine, First Hospital of Jilin University, Changchun, People’s Republic of China
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Prediction of the Effects of Missense Mutations on Human Myeloperoxidase Protein Stability Using In Silico Saturation Mutagenesis. Genes (Basel) 2022; 13:genes13081412. [PMID: 36011324 PMCID: PMC9407467 DOI: 10.3390/genes13081412] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Revised: 08/04/2022] [Accepted: 08/06/2022] [Indexed: 11/16/2022] Open
Abstract
Myeloperoxidase (MPO) is a heme peroxidase with microbicidal properties. MPO plays a role in the host's innate immunity by producing reactive oxygen species inside the cell against foreign organisms. However, there is little functional evidence linking missense mutations to human diseases. We utilized in silico saturation mutagenesis to generate and analyze the effects of 10,811 potential missense mutations on MPO stability. Our results showed that ~71% of the potential missense mutations destabilize MPO, and ~8% stabilize the MPO protein. We showed that G402W, G402Y, G361W, G402F, and G655Y would have the highest destabilizing effect on MPO. Meanwhile, D264L, G501M, D264H, D264M, and G501L have the highest stabilization effect on the MPO protein. Our computational tool prediction showed the destabilizing effects in 13 out of 14 MPO missense mutations that cause diseases in humans. We also analyzed putative post-translational modification (PTM) sites on the MPO protein and mapped the PTM sites to disease-associated missense mutations for further analysis. Our analysis showed that R327H associated with frontotemporal dementia and R548W causing generalized pustular psoriasis are near these PTM sites. Our results will aid further research into MPO as a biomarker for human complex diseases and a candidate for drug target discovery.
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Kongkiatkamon S, Terkawi L, Guan Y, Adema V, Hasipek M, Dombrovski T, Co M, Walter W, Awada H, Parker Y, Hutter S, Pagliuca S, Gurnari C, Rogers HJ, Meggendorfer M, Lindner DJ, Haferlach T, Visconte V, LaFramboise T, Jha BK, Maciejewski JP. Rare germline alterations of myeloperoxidase predispose to myeloid neoplasms. Leukemia 2022; 36:2086-2096. [PMID: 35761024 DOI: 10.1038/s41375-022-01630-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2022] [Revised: 06/06/2022] [Accepted: 06/09/2022] [Indexed: 11/09/2022]
Abstract
Myeloperoxidase (MPO) gene alterations with variable clinical penetrance have been found in hereditary MPO deficiency, but their leukemia association in patients and carriers has not been established. Germline MPO alterations were found to be significantly enriched in myeloid neoplasms: 28 pathogenic/likely pathogenic variants were identified in 100 patients. The most common alterations were c.2031-2 A > C, R569W, M519fs* and Y173C accounting for about half of the cases. While functional experiments showed that the marrow stem cell pool of Mpo-/- mice was not increased, using competitive repopulation demonstrated that Mpo-/- grafts gained growth advantage over MPO wild type cells. This finding also correlated with increased clonogenic potential after serial replating in the setting of H2O2-induced oxidative stress. Furthermore, we demonstrated that H2O2-induced DNA damage and activation of error-prone DNA repair may result in secondary genetic damage potentially predisposing to leukemia leukemic evolution. In conclusion, our study for the first time demonstrates that germline MPO variants may constitute risk alleles for MN evolution.
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Affiliation(s)
- Sunisa Kongkiatkamon
- Department of Translational Hematology and Oncology Research, Taussig Cancer Institute, Cleveland Clinic, Cleveland, OH, USA.,Research Unit in Translational Hematology, Division of Hematology, Department of Medicine, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
| | - Laila Terkawi
- Department of Translational Hematology and Oncology Research, Taussig Cancer Institute, Cleveland Clinic, Cleveland, OH, USA
| | - Yihong Guan
- Department of Translational Hematology and Oncology Research, Taussig Cancer Institute, Cleveland Clinic, Cleveland, OH, USA
| | - Vera Adema
- Department of Translational Hematology and Oncology Research, Taussig Cancer Institute, Cleveland Clinic, Cleveland, OH, USA
| | - Metis Hasipek
- Department of Translational Hematology and Oncology Research, Taussig Cancer Institute, Cleveland Clinic, Cleveland, OH, USA
| | - Tatiana Dombrovski
- Genetics and Genome Sciences, Case Western Reserve University, Cleveland, OH, USA
| | - Milo Co
- Department of Translational Hematology and Oncology Research, Taussig Cancer Institute, Cleveland Clinic, Cleveland, OH, USA
| | | | - Hassan Awada
- Department of Translational Hematology and Oncology Research, Taussig Cancer Institute, Cleveland Clinic, Cleveland, OH, USA
| | - Yvonne Parker
- Department of Translational Hematology and Oncology Research, Taussig Cancer Institute, Cleveland Clinic, Cleveland, OH, USA
| | | | - Simona Pagliuca
- Department of Translational Hematology and Oncology Research, Taussig Cancer Institute, Cleveland Clinic, Cleveland, OH, USA
| | - Carmelo Gurnari
- Department of Translational Hematology and Oncology Research, Taussig Cancer Institute, Cleveland Clinic, Cleveland, OH, USA
| | - Heesun J Rogers
- Department of Laboratory Medicine, Cleveland Clinic, Cleveland, OH, USA
| | | | - Daniel J Lindner
- Department of Translational Hematology and Oncology Research, Taussig Cancer Institute, Cleveland Clinic, Cleveland, OH, USA
| | | | - Valeria Visconte
- Department of Translational Hematology and Oncology Research, Taussig Cancer Institute, Cleveland Clinic, Cleveland, OH, USA
| | - Thomas LaFramboise
- Genetics and Genome Sciences, Case Western Reserve University, Cleveland, OH, USA
| | - Babal K Jha
- Department of Translational Hematology and Oncology Research, Taussig Cancer Institute, Cleveland Clinic, Cleveland, OH, USA
| | - Jaroslaw P Maciejewski
- Department of Translational Hematology and Oncology Research, Taussig Cancer Institute, Cleveland Clinic, Cleveland, OH, USA.
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Ge BJ, Zhao P, Li HT, Sang R, Wang M, Zhou HY, Zhang XM. Taraxacum mongolicum protects against Staphylococcus aureus-infected mastitis by exerting anti-inflammatory role via TLR2-NF-κB/MAPKs pathways in mice. JOURNAL OF ETHNOPHARMACOLOGY 2021; 268:113595. [PMID: 33212175 DOI: 10.1016/j.jep.2020.113595] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Revised: 10/06/2020] [Accepted: 11/12/2020] [Indexed: 06/11/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE As a traditional Chinese medicine, Taraxacum mongolicum has been widely used for the prevention and treatment of a variety of inflammatory and infectious diseases, and also clinically used as a remedy for mastitis. However, the scientific rationale and mechanism behind its use on mastitis in vivo are still unclear. AIM OF THE STUDY This study aimed to investigate the protective effect and potential mechanism of Taraxacum mongolicum Hand.-Mazz. (T. mongolicum) on mastitis infected by Staphylococcus aureus (S. aureus). MATERIALS AND METHODS Female ICR mice were given intragastrically 2.5, 5 and 10 g/kg of T. mongolicum extract twice per day for 6 consecutive days, and infected with S. aureus via teat canal to induce mastitis. Pro-inflammatory cytokine tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6) and interleukin-1β (IL-1β) levels were determined by ELISA. Myeloperoxidase (MPO) activity and distribution were measured by reagent kit and immunohistochemistry. Histopathological changes of mammary gland tissues were observed by H&E staining. Toll-like receptor 2 (TLR2) expression, phosphorylations of related proteins in nuclear factor-kappa B (NF-κB) and mitogen-activated protein kinases (MAPKs) signaling pathways were detected by western blot. RESULTS T. mongolicum decreased TNF-α, IL-6 and IL-1β levels, and reduced MPO activity and distribution in sera and mammary glands with S. aureus-infected mastitis. In addition, T. mongolicum effectively attenuated histopathological damages and cell necrosis of mammary gland tissues infected by S. aureus. Moreover, T. mongolicum inhibited the expression of TLR2, and the phosphorylations of inhibitor κBα (IκBα), p65, p38, extracellular signal-regulated kinase 1/2 (ERK1/2) and c-Jun N-terminal kinase (JNK) proteins in mammary glands with S. aureus-infected mastitis. CONCLUSIONS This study suggests that T. mongolicum protects against S. aureus-infected mastitis by exerting anti-inflammatory role, which is attributed to the inhibition of TLR2-NF-κB/MAPKs pathways.
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Affiliation(s)
- Bing-Jie Ge
- Agricultural College of Yanbian University, Gongyuan Street, Yanji, Jilin, 133002, China.
| | - Peng Zhao
- Agricultural College of Yanbian University, Gongyuan Street, Yanji, Jilin, 133002, China.
| | - Hai-Tao Li
- Agricultural College of Yanbian University, Gongyuan Street, Yanji, Jilin, 133002, China; Institute of Special Wild Economic Animals and Plants, Chinese Academy of Agricultural Sciences, Juye Street, Changchun, Jilin 132109, China.
| | - Rui Sang
- Agricultural College of Yanbian University, Gongyuan Street, Yanji, Jilin, 133002, China.
| | - Meng Wang
- Agricultural College of Yanbian University, Gongyuan Street, Yanji, Jilin, 133002, China.
| | - Hong-Yuan Zhou
- Agricultural College of Yanbian University, Gongyuan Street, Yanji, Jilin, 133002, China.
| | - Xue-Mei Zhang
- Agricultural College of Yanbian University, Gongyuan Street, Yanji, Jilin, 133002, China.
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Needham PG, Guerriero CJ, Brodsky JL. Chaperoning Endoplasmic Reticulum-Associated Degradation (ERAD) and Protein Conformational Diseases. Cold Spring Harb Perspect Biol 2019; 11:cshperspect.a033928. [PMID: 30670468 DOI: 10.1101/cshperspect.a033928] [Citation(s) in RCA: 85] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Misfolded proteins compromise cellular homeostasis. This is especially problematic in the endoplasmic reticulum (ER), which is a high-capacity protein-folding compartment and whose function requires stringent protein quality-control systems. Multiprotein complexes in the ER are able to identify, remove, ubiquitinate, and deliver misfolded proteins to the 26S proteasome for degradation in the cytosol, and these events are collectively termed ER-associated degradation, or ERAD. Several steps in the ERAD pathway are facilitated by molecular chaperone networks, and the importance of ERAD is highlighted by the fact that this pathway is linked to numerous protein conformational diseases. In this review, we discuss the factors that constitute the ERAD machinery and detail how each step in the pathway occurs. We then highlight the underlying pathophysiology of protein conformational diseases associated with ERAD.
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Affiliation(s)
- Patrick G Needham
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania 15260
| | | | - Jeffrey L Brodsky
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania 15260
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Buchan KD, Prajsnar TK, Ogryzko NV, de Jong NWM, van Gent M, Kolata J, Foster SJ, van Strijp JAG, Renshaw SA. A transgenic zebrafish line for in vivo visualisation of neutrophil myeloperoxidase. PLoS One 2019; 14:e0215592. [PMID: 31002727 PMCID: PMC6474608 DOI: 10.1371/journal.pone.0215592] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2018] [Accepted: 04/04/2019] [Indexed: 12/12/2022] Open
Abstract
The neutrophil enzyme myeloperoxidase (MPO) is a major enzyme made by neutrophils to generate antimicrobial and immunomodulatory compounds, notably hypochlorous acid (HOCl), amplifying their capacity for destroying pathogens and regulating inflammation. Despite its roles in innate immunity, the importance of MPO in preventing infection is unclear, as individuals with MPO deficiency are asymptomatic with the exception of an increased risk of candidiasis. Dysregulation of MPO activity is also linked with inflammatory conditions such as atherosclerosis, emphasising a need to understand the roles of the enzyme in greater detail. Consequently, new tools for investigating granular dynamics in vivo can provide useful insights into how MPO localises within neutrophils, aiding understanding of its role in preventing and exacerbating disease. The zebrafish is a powerful model for investigating the immune system in vivo, as it is genetically tractable, and optically transparent. To visualise MPO activity within zebrafish neutrophils, we created a genetic construct that expresses human MPO as a fusion protein with a C-terminal fluorescent tag, driven by the neutrophil-specific promoter lyz. After introducing the construct into the zebrafish genome by Tol2 transgenesis, we established the Tg(lyz:Hsa.MPO-mEmerald,cmlc2:EGFP)sh496 line, and confirmed transgene expression in zebrafish neutrophils. We observed localisation of MPO-mEmerald within a subcellular location resembling neutrophil granules, mirroring MPO in human neutrophils. In Spotless (mpxNL144) larvae-which express a non-functional zebrafish myeloperoxidase-the MPO-mEmerald transgene does not disrupt neutrophil migration to sites of infection or inflammation, suggesting that it is a suitable line for the study of neutrophil granule function. We present a new transgenic line that can be used to investigate neutrophil granule dynamics in vivo without disrupting neutrophil behaviour, with potential applications in studying processing and maturation of MPO during development.
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Affiliation(s)
- Kyle D. Buchan
- The Bateson Centre and Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield, Western Bank, Sheffield, United Kingdom
| | - Tomasz K. Prajsnar
- The Bateson Centre and Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield, Western Bank, Sheffield, United Kingdom
| | - Nikolay V. Ogryzko
- The Bateson Centre and Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield, Western Bank, Sheffield, United Kingdom
- Centre for Inflammation Research, University of Edinburgh, Edinburgh, United Kingdom
| | - Nienke W. M. de Jong
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Michiel van Gent
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Julia Kolata
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Simon J. Foster
- Department of Molecular Biology and Biotechnology, University of Sheffield, Western Bank, Sheffield, United Kingdom
| | - Jos A. G. van Strijp
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Stephen A. Renshaw
- The Bateson Centre and Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield, Western Bank, Sheffield, United Kingdom
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Ahn C, Kang JH, Jeung EB. Calcium homeostasis in diabetes mellitus. J Vet Sci 2018; 18:261-266. [PMID: 28927245 PMCID: PMC5639077 DOI: 10.4142/jvs.2017.18.3.261] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Revised: 04/16/2017] [Accepted: 05/05/2017] [Indexed: 12/13/2022] Open
Abstract
Diabetes mellitus (DM) is becoming a lifestyle-related pandemic disease. Diabetic patients frequently develop electrolyte disorders, especially diabetic ketoacidosis or nonketotic hyperglycemic hyperosmolar syndrome. Such patients show characteristic potassium, magnesium, phosphate, and calcium depletion. In this review, we discuss a homeostatic mechanism that links calcium and DM. We also provide a synthesis of the evidence in favor or against this linking mechanism by presenting recent clinical indications, mainly from veterinary research. There are consistent results supporting the use of calcium and vitamin D supplementation to reduce the risk of DM. Clinical trials support a marginal reduction in circulating lipids, and some meta-analyses support an increase in insulin sensitivity, following vitamin D supplementation. This review provides an overview of the calcium and vitamin D disturbances occurring in DM and describes the underlying mechanisms. Such elucidation will help indicate potential pathophysiology-based precautionary and therapeutic approaches and contribute to lowering the incidence of DM.
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Affiliation(s)
- Changhwan Ahn
- Laboratory of Veterinary Biochemistry and Molecular Biology, College of Veterinary Medicine, Chungbuk National University, Cheongju 28644, Korea
| | - Ji-Houn Kang
- Laboratory of Veterinary Internal Medicine, Veterinary Medical Center and College of Veterinary Medicine, Chungbuk National University, Cheongju 28644, Korea
| | - Eui-Bae Jeung
- Laboratory of Veterinary Biochemistry and Molecular Biology, College of Veterinary Medicine, Chungbuk National University, Cheongju 28644, Korea
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Biosynthesis of human myeloperoxidase. Arch Biochem Biophys 2018; 642:1-9. [PMID: 29408362 DOI: 10.1016/j.abb.2018.02.001] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2018] [Revised: 01/31/2018] [Accepted: 02/02/2018] [Indexed: 01/30/2023]
Abstract
Members of Chordata peroxidase subfamily [1] expressed in mammals, including myeloperoxidase (MPO), eosinophil peroxidase (EPO), lactoperoxidase (LPO), and thyroid peroxidase (TPO), express conserved motifs around the heme prosthetic group essential for their activity, a calcium-binding site, and at least two covalent bonds linking the heme group to the protein backbone. Although most studies of the biosynthesis of these peroxidases have focused on MPO, many of the features described occur during biosynthesis of other members of the protein subfamily. Whereas MPO biosynthesis includes events typical for proteins generated in the secretory pathway, the importance and consequences of heme insertion are events uniquely associated with peroxidases. This Review summarizes decades of work elucidating specific steps in the biosynthetic pathway of human MPO. Discussion includes cotranslational glycosylation and subsequent modifications of the N-linked carbohydrate sidechains, contributions by molecular chaperones in the endoplasmic reticulum, cleavage of the propeptide from proMPO, and proteolytic processing of protomers and dimerization to yield mature MPO. Parallels between the biosynthesis of MPO and TPO as well as the impact of inherited mutations in the MPO gene on normal biosynthesis will be summarized. Lastly, specific gaps in our knowledge revealed by this review of our current understanding will be highlighted.
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Brief Report: Progression of Atherosclerosis in HIV-Infected Individuals-Prospective Data From an Asian Cohort. J Acquir Immune Defic Syndr 2017; 75:198-202. [PMID: 28498145 DOI: 10.1097/qai.0000000000001358] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
BACKGROUND The magnitude and risk factors of progression of atherosclerosis in Asian HIV-infected individuals were unknown. This study aimed to evaluate: (1) the rate of progression of atherosclerosis in HIV-infected individuals, and (2) metabolic and inflammatory parameters that may predict atherosclerosis progression in HIV-infected individuals in an Asian cohort. SETTING A prospective, longitudinal study was performed among adults attending an HIV Metabolic clinic in Hong Kong. METHODS Carotid intima media thickness (cIMT) was measured at baseline and 24 months. Body composition, metabolic, and inflammatory biomarkers [including homeostasis model assessment of insulin resistance, LDL (low-density lipoprotein) cholesterol particle size, high-sensitive C reactive protein, adiponectin] associated with cIMT change were analyzed; their predictive performances were estimated using receiver operating characteristic analyses. RESULTS Sixty-one HIV-infected individuals (mean ± SD age 49.8 ± 11.4 years, 89% men, 97% Chinese, diabetes 39%, hypertension 30%, and dyslipidemia 85%) were recruited. Annual rate of change of cIMT was +0.0075 (0.0000-0.0163) mm/yr, and 19% developed new plaque at 24 months. Two patients died during the study period, 1 because of sudden cardiac death. Using receiver operating characteristic analyses, combination of lower limb fat percentage, LDL cholesterol subclass pattern B, and lower adiponectin level, but not Framingham score, predicted greater cIMT progression in HIV-infected individuals. CONCLUSIONS Asian HIV-infected individuals had atherosclerosis progression. Limb fat percentage, LDL cholesterol particle size, and adiponectin level may identify at-risk Asian HIV-infected individuals for early intervention.
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Grishkovskaya I, Paumann-Page M, Tscheliessnig R, Stampler J, Hofbauer S, Soudi M, Sevcnikar B, Oostenbrink C, Furtmüller PG, Djinović-Carugo K, Nauseef WM, Obinger C. Structure of human promyeloperoxidase (proMPO) and the role of the propeptide in processing and maturation. J Biol Chem 2017; 292:8244-8261. [PMID: 28348079 PMCID: PMC5437232 DOI: 10.1074/jbc.m117.775031] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2017] [Revised: 03/09/2017] [Indexed: 11/06/2022] Open
Abstract
Myeloperoxidase (MPO) is synthesized by neutrophil and monocyte precursor cells and contributes to host defense by mediating microbial killing. Although several steps in MPO biosynthesis and processing have been elucidated, many questions remained, such as the structure-function relationship of monomeric unprocessed proMPO versus the mature dimeric MPO and the functional role of the propeptide. Here we have presented the first and high resolution (at 1.25 Å) crystal structure of proMPO and its solution structure obtained by small-angle X-ray scattering. Promyeloperoxidase hosts five occupied glycosylation sites and six intrachain cystine bridges with Cys-158 of the very flexible N-terminal propeptide being covalently linked to Cys-319 and thereby hindering homodimerization. Furthermore, the structure revealed (i) the binding site of proMPO-processing proconvertase, (ii) the structural motif for subsequent cleavage to the heavy and light chains of mature MPO protomers, and (iii) three covalent bonds between heme and the protein. Studies of the mutants C158A, C319A, and C158A/C319A demonstrated significant differences from the wild-type protein, including diminished enzymatic activity and prevention of export to the Golgi due to prolonged association with the chaperone calnexin. These structural and functional findings provide novel insights into MPO biosynthesis and processing.
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Affiliation(s)
- Irina Grishkovskaya
- Department of Structural and Computational Biology, Max F. Perutz Laboratories, University of Vienna, A-1030 Vienna, Austria
| | - Martina Paumann-Page
- Department of Chemistry, Division of Biochemistry, BOKU-University of Natural Resources and Life Sciences, Muthgasse 18, A-1190 Vienna, Austria
| | - Rupert Tscheliessnig
- Austrian Centre of Industrial Biotechnology (ACIB), Muthgasse 11, A-1190 Vienna, Austria
| | - Johanna Stampler
- Department of Chemistry, Division of Biochemistry, BOKU-University of Natural Resources and Life Sciences, Muthgasse 18, A-1190 Vienna, Austria
| | - Stefan Hofbauer
- Department of Structural and Computational Biology, Max F. Perutz Laboratories, University of Vienna, A-1030 Vienna, Austria
| | - Monika Soudi
- Department of Chemistry, Division of Biochemistry, BOKU-University of Natural Resources and Life Sciences, Muthgasse 18, A-1190 Vienna, Austria
| | - Benjamin Sevcnikar
- Department of Chemistry, Division of Biochemistry, BOKU-University of Natural Resources and Life Sciences, Muthgasse 18, A-1190 Vienna, Austria
| | - Chris Oostenbrink
- Department of Material Sciences and Process Engineering, Institute of Molecular Modeling and Simulation, BOKU-University of Natural Resources and Life Sciences, A-1190 Vienna, Austria
| | - Paul G Furtmüller
- Department of Chemistry, Division of Biochemistry, BOKU-University of Natural Resources and Life Sciences, Muthgasse 18, A-1190 Vienna, Austria
| | - Kristina Djinović-Carugo
- Department of Structural and Computational Biology, Max F. Perutz Laboratories, University of Vienna, A-1030 Vienna, Austria; Department of Biochemistry, Faculty of Chemistry and Chemical Technology, University of Ljubljana, Veĉna pot 113, 1000 Ljubljana, Slovenia
| | - William M Nauseef
- Inflammation Program and Department of Medicine, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242.
| | - Christian Obinger
- Department of Chemistry, Division of Biochemistry, BOKU-University of Natural Resources and Life Sciences, Muthgasse 18, A-1190 Vienna, Austria.
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12
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Identification of PNGase-dependent ERAD substrates in Saccharomyces cerevisiae. Biochem J 2016; 473:3001-12. [DOI: 10.1042/bcj20160453] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2015] [Accepted: 07/18/2016] [Indexed: 12/24/2022]
Abstract
Endoplasmic reticulum (ER)-associated degradation (ERAD) is a proteolytic pathway for handling misfolded or improperly assembled proteins that are synthesized in the ER. Cytoplasmic peptide:N-glycanase (PNGase) is a deglycosylating enzyme that cleaves N-glycans that are attached to ERAD substrates. While the critical roles of N-glycans in monitoring the folding status of carrier proteins in the ER lumen are relatively well understood, the physiological role of PNGase-mediated deglycosylation in the cytosol remained poorly understood. We report herein the identification of endogenous substrates for the cytoplasmic PNGase in Saccharomyces cerevisiae. Using an isotope-coded glycosylation site-specific tagging (IGOT) method-based LC/MS analysis, 11 glycoproteins were specifically detected in the cytosol of PNGase-deletion cells (png1Δ). Among these molecules, at least five glycoproteins were clearly identified as ERAD substrates in vivo. Moreover, four out of the five proteins were found to be either deglycosylated by PNGase in vivo or the overall degradation was delayed in a png1Δ mutant. Our results clearly indicate that the IGOT method promises to be a powerful tool for the identification of endogenous substrates for the cytoplasmic PNGase.
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13
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Homozygous calreticulin mutations in patients with myelofibrosis lead to acquired myeloperoxidase deficiency. Blood 2016; 127:3253-9. [DOI: 10.1182/blood-2016-02-696310] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Accepted: 03/22/2016] [Indexed: 12/18/2022] Open
Abstract
Key Points
Acquired MPO deficiency in patients with MPN is uniquely associated with homozygous CALR mutations. In line with a posttranscriptional defect, MPO deficiency results from reduced MPO protein levels, but not from decreased MPO mRNA.
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14
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Korolnek T, Hamza I. Like iron in the blood of the people: the requirement for heme trafficking in iron metabolism. Front Pharmacol 2014; 5:126. [PMID: 24926267 PMCID: PMC4045156 DOI: 10.3389/fphar.2014.00126] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2014] [Accepted: 05/12/2014] [Indexed: 12/17/2022] Open
Abstract
Heme is an iron-containing porphyrin ring that serves as a prosthetic group in proteins that function in diverse metabolic pathways. Heme is also a major source of bioavailable iron in the human diet. While the synthesis of heme has been well-characterized, the pathways for heme trafficking remain poorly understood. It is likely that heme transport across membranes is highly regulated, as free heme is toxic to cells. This review outlines the requirement for heme delivery to various subcellular compartments as well as possible mechanisms for the mobilization of heme to these compartments. We also discuss how these trafficking pathways might function during physiological events involving inter- and intra-cellular mobilization of heme, including erythropoiesis, erythrophagocytosis, heme absorption in the gut, as well as heme transport pathways supporting embryonic development. Lastly, we aim to question the current dogma that heme, in toto, is not mobilized from one cell or tissue to another, outlining the evidence for these pathways and drawing parallels to other well-accepted paradigms for copper, iron, and cholesterol homeostasis.
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Affiliation(s)
- Tamara Korolnek
- Department of Animal & Avian Sciences, University of Maryland, College Park MD, USA ; Department of Cell Biology & Molecular Genetics, University of Maryland, College Park MD, USA
| | - Iqbal Hamza
- Department of Animal & Avian Sciences, University of Maryland, College Park MD, USA ; Department of Cell Biology & Molecular Genetics, University of Maryland, College Park MD, USA
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15
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Meitzler JL, Hinde S, Bánfi B, Nauseef WM, Ortiz de Montellano PR. Conserved cysteine residues provide a protein-protein interaction surface in dual oxidase (DUOX) proteins. J Biol Chem 2013; 288:7147-57. [PMID: 23362256 DOI: 10.1074/jbc.m112.414797] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Intramolecular disulfide bond formation is promoted in oxidizing extracellular and endoplasmic reticulum compartments and often contributes to protein stability and function. DUOX1 and DUOX2 are distinguished from other members of the NOX protein family by the presence of a unique extracellular N-terminal region. These peroxidase-like domains lack the conserved cysteines that confer structural stability to mammalian peroxidases. Sequence-based structure predictions suggest that the thiol groups present are solvent-exposed on a single protein surface and are too distant to support intramolecular disulfide bond formation. To investigate the role of these thiol residues, we introduced four individual cysteine to glycine mutations in the peroxidase-like domains of both human DUOXs and purified the recombinant proteins. The mutations caused little change in the stabilities of the monomeric proteins, supporting the hypothesis that the thiol residues are solvent-exposed and not involved in disulfide bonds that are critical for structural integrity. However, the ability of the isolated hDUOX1 peroxidase-like domain to dimerize was altered, suggesting a role for these cysteines in protein-protein interactions that could facilitate homodimerization of the peroxidase-like domain or, in the full-length protein, heterodimeric interactions with a maturation protein. When full-length hDUOX1 was expressed in HEK293 cells, the mutations resulted in decreased H2O2 production that correlated with a decreased amount of the enzyme localized to the membrane surface rather than with a loss of activity or with a failure to synthesize the mutant proteins. These results support a role for the cysteine residues in intermolecular disulfide bond formation with the DUOX maturation factor DUOXA1.
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Affiliation(s)
- Jennifer L Meitzler
- Laboratory of Molecular Pharmacology of the Center for Cancer Research, NCI, National Institutes of Health, Bethesda, Maryland 20892, USA
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16
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McCormick S, Nelson A, Nauseef WM. Proconvertase proteolytic processing of an enzymatically active myeloperoxidase precursor. Arch Biochem Biophys 2012; 527:31-6. [PMID: 22902565 DOI: 10.1016/j.abb.2012.07.013] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2012] [Revised: 07/24/2012] [Accepted: 07/25/2012] [Indexed: 11/24/2022]
Abstract
Optimal and efficient killing of ingested microbes by human neutrophils is mediated in large part by the action of hypochlorous acid produced by the myeloperoxidase-H(2)O(2)-chloride system in phagosomes. Myeloperoxidase gene transcription is limited to early myeloid precursors in the bone marrow, when myeloperoxidase is synthesized and stored in azurophilic granules for subsequent release from stimulated neutrophils. Promyeloperoxidase, the 90 kDa myeloperoxidase precursor synthesized in the endoplasmic reticulum (ER), contains a 125-amino acid pro-region whose function and fate during myeloperoxidase biosynthesis are unknown. Promyeloperoxidase has two fates during myeloperoxidase biosynthesis; the majority undergoes proteolytic processing to generate mature myeloperoxidase, while the remainder is constitutively secreted from the cells in bone marrow. We used a promyelocytic cell line that produces endogenous myeloperoxidase as well as human embryonic kidney cells stably expressing normal and mutant forms of myeloperoxidase to examine proteolytic processing of promyeloperoxidase. We demonstrated that CMK-RVKR, an inhibitor of subtilisin-like proteinases, blocked cleavage of the pro-peptide of promyeloperoxidase in a post-ER compartment. Mutants with alanine substitution of basic residues in the predicted proteinase cleavage site failed to undergo maturation to normal myeloperoxidase subunits and were arrested at the promyeloperoxidase stage. Whereas specific mutants varied as to their stability, secreted promyeloperoxidase from the mutants retained the capacity to generate hypochlorous acid. Taken together, these studies demonstrate proconvertase-dependent cleavage of promyeloperoxidase as an essential step in normal proteolytic processing and granule targeting of myeloperoxidase. Furthermore, although mutations in the proteinase cleavage site reduced intracellular stability of the mutants, the integrity of the heme group was not compromised, as chlorinating activity was retained in the secreted promyeloperoxidase.
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Affiliation(s)
- Sally McCormick
- Iowa Inflammation Program and Department of Medicine, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA, USA
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17
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Guerriero CJ, Brodsky JL. The delicate balance between secreted protein folding and endoplasmic reticulum-associated degradation in human physiology. Physiol Rev 2012; 92:537-76. [PMID: 22535891 DOI: 10.1152/physrev.00027.2011] [Citation(s) in RCA: 308] [Impact Index Per Article: 25.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Protein folding is a complex, error-prone process that often results in an irreparable protein by-product. These by-products can be recognized by cellular quality control machineries and targeted for proteasome-dependent degradation. The folding of proteins in the secretory pathway adds another layer to the protein folding "problem," as the endoplasmic reticulum maintains a unique chemical environment within the cell. In fact, a growing number of diseases are attributed to defects in secretory protein folding, and many of these by-products are targeted for a process known as endoplasmic reticulum-associated degradation (ERAD). Since its discovery, research on the mechanisms underlying the ERAD pathway has provided new insights into how ERAD contributes to human health during both normal and diseases states. Links between ERAD and disease are evidenced from the loss of protein function as a result of degradation, chronic cellular stress when ERAD fails to keep up with misfolded protein production, and the ability of some pathogens to coopt the ERAD pathway. The growing number of ERAD substrates has also illuminated the differences in the machineries used to recognize and degrade a vast array of potential clients for this pathway. Despite all that is known about ERAD, many questions remain, and new paradigms will likely emerge. Clearly, the key to successful disease treatment lies within defining the molecular details of the ERAD pathway and in understanding how this conserved pathway selects and degrades an innumerable cast of substrates.
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Affiliation(s)
- Christopher J Guerriero
- Department of Biological Sciences, University of Pittsburgh, A320 Langley Hall, Pittsburgh, PA 15260, USA
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18
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Loughran NB, Hinde S, McCormick-Hill S, Leidal KG, Bloomberg S, Loughran ST, O'Connor B, O'Fágáin C, Nauseef WM, O'Connell MJ. Functional consequence of positive selection revealed through rational mutagenesis of human myeloperoxidase. Mol Biol Evol 2012; 29:2039-46. [PMID: 22355012 DOI: 10.1093/molbev/mss073] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Myeloperoxidase (MPO) is a member of the mammalian heme peroxidase (MHP) multigene family. Whereas all MHPs oxidize specific halides to generate the corresponding hypohalous acid, MPO is unique in its capacity to oxidize chloride at physiologic pH to produce hypochlorous acid (HOCl), a potent microbicide that contributes to neutrophil-mediated host defense against infection. We have previously resolved the evolutionary relationships in this functionally diverse multigene family and predicted in silico that positive Darwinian selection played a major role in the observed functional diversities (Loughran NB, O'Connor B, O'Fagain C, O'Connell MJ. 2008. The phylogeny of the mammalian heme peroxidases and the evolution of their diverse functions. BMC Evol Biol. 8:101). In this work, we have replaced positively selected residues asparagine 496 (N496), tyrosine 500 (Y500), and leucine 504 (L504) with the amino acids present in the ancestral MHP and have examined the effects on the structure, biosynthesis, and activity of MPO. Analysis in silico predicted that N496F, Y500F, or L504T would perturb hydrogen bonding in the heme pocket of MPO and thus disrupt the structural integrity of the enzyme. Biosynthesis of the mutants stably expressed in human embryonic kidney 293 cells yielded apoproMPO, the heme-free, enzymatically inactive precursor of MPO, that failed to undergo normal maturation or proteolytic processing. As a consequence of the maturational arrest at the apoproMPO stage of development, cells expressing MPO with mutations N496F, Y500F, L504T, individually or in combination, lacked normal peroxidase or chlorinating activity. Taken together, our data provide further support for the in silico predictions of positive selection and highlight the correlation between positive selection and functional divergence. Our data demonstrate that directly probing the functional importance of positive selection can provide important insights into understanding protein evolution.
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Affiliation(s)
- Noeleen B Loughran
- School of Biotechnology, Dublin City University, Glasnevin, Dublin, Ireland
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19
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van der Veen BS, de Winther MPJ, Heeringa P. Myeloperoxidase: molecular mechanisms of action and their relevance to human health and disease. Antioxid Redox Signal 2009; 11:2899-937. [PMID: 19622015 DOI: 10.1089/ars.2009.2538] [Citation(s) in RCA: 372] [Impact Index Per Article: 24.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Myeloperoxidase (MPO) is a heme-containing peroxidase abundantly expressed in neutrophils and to a lesser extent in monocytes. Enzymatically active MPO, together with hydrogen peroxide and chloride, produces the powerful oxidant hypochlorous acid and is a key contributor to the oxygen-dependent microbicidal activity of phagocytes. In addition, excessive generation of MPO-derived oxidants has been linked to tissue damage in many diseases, especially those characterized by acute or chronic inflammation. It has become increasingly clear that MPO exerts effects that are beyond its oxidative properties. These properties of MPO are, in many cases, independent of its catalytic activity and affect various processes involved in cell signaling and cell-cell interactions and are, as such, capable of modulating inflammatory responses. Given these diverse effects, an increased interest has emerged in the role of MPO and its downstream products in a wide range of inflammatory diseases. In this article, our knowledge pertaining to the biologic role of MPO and its downstream effects and mechanisms of action in health and disease is reviewed and discussed.
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Affiliation(s)
- Betty S van der Veen
- Department of Pathology and Medical Biology, University Medical Center Groningen, University of Groningen , Groningen, the Netherlands
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20
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Abstract
The aim of this study is to summarize the available molecular epidemiologic studies of lung cancer and metabolic genes, such as NAD(P)H quinone reductase 1 (NQO1) and myeloperoxidase (MPO). NQO1 plays a dual role in the detoxification and activation of procarcinogens whereas MPO has Phase I activity by converting lipophilic carcinogens into hydrophilic forms. Variant genotypes of both NQO1 Pro187 Ser and MPO G-463A polymorphisms may be related to low enzyme activity. The Pro/Ser and Ser/Ser genotypes combined of NQO1 was significantly associated with decreased risk of lung cancer in Japanese [random effects odds ratio (OR) = 0.70, 95% confidence interval (CI) = 0.56-0.88] among whom the variant allele is common. The variant genotype of MPO was associated with decreased risk of lung cancer among Caucasians (random effects OR = 0.70, 95% CI = 0.47-1.04). Gene-environment interactions in both polymorphisms may be hampered by inaccurate categorization of tobacco exposure. Evidence on gene-gene interactions is extremely limited. As lung cancer is a multifactorial disease, an improved understanding of such interactions may help identify individuals at risk for developing lung cancer. Such a study should include larger sample size and other polymorphisms in the metabolism of tobacco-derived carcinogens and address interactions with smoking status. The effects of polymorphisms are best represented by their haplotypes. In future studies on lung cancer, the development of haplotype-based approaches will facilitate the evaluation of haplotypic effects, either for selected polymorphisms physically close to each other or for multiple genes within the same drug-metabolism pathway.
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Affiliation(s)
- Chikako Kiyohara
- Department of Preventive Medicine, Graduate School of Medical Sciences, Kyushu University, Maidashi, Fukuoka, Japan
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21
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Hebert DN, Molinari M. In and out of the ER: protein folding, quality control, degradation, and related human diseases. Physiol Rev 2007; 87:1377-408. [PMID: 17928587 DOI: 10.1152/physrev.00050.2006] [Citation(s) in RCA: 484] [Impact Index Per Article: 28.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
A substantial fraction of eukaryotic gene products are synthesized by ribosomes attached at the cytosolic face of the endoplasmic reticulum (ER) membrane. These polypeptides enter cotranslationally in the ER lumen, which contains resident molecular chaperones and folding factors that assist their maturation. Native proteins are released from the ER lumen and are transported through the secretory pathway to their final intra- or extracellular destination. Folding-defective polypeptides are exported across the ER membrane into the cytosol and destroyed. Cellular and organismal homeostasis relies on a balanced activity of the ER folding, quality control, and degradation machineries as shown by the dozens of human diseases related to defective maturation or disposal of individual polypeptides generated in the ER.
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Affiliation(s)
- Daniel N Hebert
- Department of Biochemistry and Molecular Biology, Program in Molecular and Cellular Biology, University of Massachusetts, Amherst, Massachusetts 01003, USA.
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22
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Schmalstieg FC, Keeney SE, Rudloff HE, Palkowetz KH, Cevallos M, Zhou X, Cox RA, Hawkins HK, Traber DL, Zwischenberger JB. Arteriovenous CO2 removal improves survival compared to high frequency percussive and low tidal volume ventilation in a smoke/burn sheep acute respiratory distress syndrome model. Ann Surg 2007; 246:512-21; discussion 521-3. [PMID: 17717455 PMCID: PMC1959342 DOI: 10.1097/sla.0b013e318148c6e6] [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: 10/22/2022]
Abstract
UNLABELLED OBJECTIVES AND SUMMARY BACKGROUND: Low tidal volume ventilation (LTV) has improved survival with acute respiratory distress syndrome (ARDS) by reducing lung stretch associated with volutrauma and barotrauma. Additional strategies to reduce lung stretch include arteriovenous carbon dioxide removal (AVCO2R), and high frequency percussive ventilation (HFPV). We performed a prospective, randomized study comparing these techniques in our clinically relevant LD100 sheep model of ARDS to compare survival, pathology, and inflammation between the 3 ventilator methods. METHODS Adult sheep (n = 61) received smoke inhalation (48 breaths) and a 40% third-degree burn. After ARDS developed (Pao2/FiO2 <200), animals were randomized. In experiment 1, animals were killed at 48 hours after randomization. Hemodynamics, pulmonary function, injury scores, myeloperoxidase (MPO) in lung tissues and neutrophils, IL-8 in lung tissues, and apoptosis were evaluated. In experiment 2, the end point was survival to 72 hours after onset of ARDS or end-of-life criteria with extension of the same studies performed in experiment 1. RESULTS There were no differences in hemodynamics, but minute ventilation was lower in the AVCO2R group and Paco2 for the HFPV and AVCO2R animals remained lower than LTV. Airway obstruction and injury scores were not different among the 3 ventilation strategies. In experiment 1, lung tissue MPO and IL-8 were not different among the ventilation strategies. However, in experiment 2, lung tissue MPO was significantly lower for AVCO2R-treated animals (AVCO2R < HFPV < LTV). TUNEL staining showed little DNA breakage in neutrophils from experiment 1, but significantly increased breakage in all 3 ventilator strategies in experiment 2. In contrast, AVCO2R tissue neutrophils showed significant apoptosis at 72 hours post-ARDS criteria as measured by nuclear condensation (P < 0.001). Survival 72 hours post-ARDS criteria was highest for AVCO2R (71%) compared with HFPV (55%) and LTV (33%) (AVCO2R vs. LTV, P = 0.05). CONCLUSIONS Significantly more animals survived AVCO2R than LTV. In experiment 2, Lung MPO was significantly lower for AVCO2R, compared with LTV (P < 0.05). This finding taken together with the TUNEL and neutrophil apoptosis results, suggested that disposition of neutrophils 72 hours post-ARDS criteria was different among the ventilatory strategies with neutrophils from AVCO2R-treated animals removed chiefly through apoptosis, but in the cases of HFPV and LTV, dying by necrosis in lung tissue.
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Affiliation(s)
- Frank C Schmalstieg
- Department of Pediatrics, University of Texas Medical Branch, Galveston, TX 77555, USA.
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23
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Goedken M, McCormick S, Leidal KG, Suzuki K, Kameoka Y, Astern JM, Huang M, Cherkasov A, Nauseef WM. Impact of Two Novel Mutations on the Structure and Function of Human Myeloperoxidase. J Biol Chem 2007; 282:27994-8003. [PMID: 17650507 DOI: 10.1074/jbc.m701984200] [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: 01/05/2023] Open
Abstract
The heme protein myeloperoxidase (MPO) contributes critically to O(2)-dependent neutrophil antimicrobial activity. Two Japanese adults were identified with inherited MPO deficiency because of mutations at Arg-499 or Gly-501, conserved residues near the proximal histidine in the heme pocket. Because of the proximity of these residues to a critical histidine in the heme pocket, we examined the biosynthesis, function, and spectral properties of the peroxidase stably expressed in human embryonic kidney cells. Biosynthesis of normal MPO by human embryonic kidney cells faithfully mirrored events previously identified in cells expressing endogenous MPO. Mutant apopro-MPO was 90 kDa and interacted normally with the molecular chaperones ERp57, calreticulin, and calnexin in the endoplasmic reticulum. However, mutant precursors were not proteolytically processed into subunits of MPO, although secretion of the unprocessed precursors occurred normally. Although delta-[(14)C]aminolevulinic acid incorporation demonstrated formation of pro-MPO in both mutants, neither protein was enzymatically active. The Soret band for each mutant was shifted from the normal 430 to approximately 412 nm, confirming that heme was incorporated but suggesting that the number of covalent bonds or other structural aspects of the heme pocket were disrupted by the mutations. These studies demonstrate that despite heme incorporation, mutations in the heme environs compromised the oxidizing potential of MPO.
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Affiliation(s)
- Melissa Goedken
- Inflammation Program, Department of Medicine, University of Iowa and Veterans Affairs Medical Center, Iowa City, Iowa 52241, USA
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Taioli E, Benhamou S, Bouchardy C, Cascorbi I, Cajas-Salazar N, Dally H, Fong KM, Larsen JE, Le Marchand L, London SJ, Risch A, Spitz MR, Stucker I, Weinshenker B, Wu X, Yang P. Myeloperoxidase G-463A polymorphism and lung cancer: a HuGE genetic susceptibility to environmental carcinogens pooled analysis. Genet Med 2007; 9:67-73. [PMID: 17304047 DOI: 10.1097/gim.0b013e31803068b1] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Myeloperoxidase is a phase I metabolic enzyme that converts the metabolites of benzo[a]pyrene from tobacco smoke into highly reactive epoxides. A polymorphism in the promoter region of myeloperoxidase (463G-->A) has been found to be inversely associated with lung cancer; differences in the association with age and gender have been suggested. We conducted a pooled analysis of individual data from 10 studies (3688 cases and 3874 controls) from the Genetic Susceptibility to Environmental Carcinogens database. The odds ratio for lung cancer was 0.88 (95% confidence interval: 0.80-0.97) for the AG variant of myeloperoxidase G-463A polymorphism, and 0.71 (95% confidence interval: 0.57-0.88) for the AA variant after adjusting for smoking, age, gender, and ethnicity. The inverse association between lung cancer and myeloperoxidase G-463A polymorphism was equally found in males and females (odds ratio for the AA genotype 0.73 [95% confidence interval: 0.56-0.96] and 0.67 [95% confidence interval: 0.46-0.98], respectively), without differences in the association according to age in the two genders. The myeloperoxidase G-463A polymorphism was significantly protective in "ever" smokers but not in "never" smokers. Myeloperoxidase is a key enzyme in tobacco-induced carcinogenesis.
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Affiliation(s)
- Emanuela Taioli
- University of Pittsburgh, Cancer Institute, Pittsburgh, Pensylvania 15232, USA
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25
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Grasberger H, De Deken X, Miot F, Pohlenz J, Refetoff S. Missense mutations of dual oxidase 2 (DUOX2) implicated in congenital hypothyroidism have impaired trafficking in cells reconstituted with DUOX2 maturation factor. Mol Endocrinol 2007; 21:1408-21. [PMID: 17374849 DOI: 10.1210/me.2007-0018] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Dual oxidase 2 (DUOX2), a reduced NAD phosphate:O2 oxidoreductase flavoprotein, is a component of the thyrocyte H2O2 generator required for hormone synthesis at the apical plasma membrane. We recently identified a specific DUOX2 maturation factor (DUOXA2) that is necessary and sufficient for expression of functional DUOX2 in mammalian cell lines. We have now used a DUOXA2 reconstituted system to provide the first characterization of natural DUOX2 missense variants (Q36H, R376W, D506N) at the molecular level, analyzing their impact on H2O2 generation, trafficking, stability, folding, and DUOXA2 interaction. The Q36H and R376W mutations completely prevent routing of DUOX2 to the cell surface. The mutant proteins are predominantly present as core N-glycosylated, thiol-reduced folding intermediates, which are retained by the quality control system within the endoplasmic reticulum (ER) as indicated by increased complexation with the lectin calnexin. D506N displays a partial deficiency phenotype with reduced surface expression of a mutant protein with normal intrinsic activity in generating H2O2. D506N N-glycan moieties are not subject to normal modification in the Golgi apparatus, suggesting that nonnative protein can escape the quality control in the ER. Oxidative folding of DUOX2 in the ER appears to be the rate-limiting step in the maturation of DUOX2, but is not facilitated by DUOXA2. Rather, DUOXA2 allows rapid ER exit of folded DUOX2 or enhanced degradation of mutant DUOX2 proteins not competent for ER exit. DUOXA2 may thus be part of a secondary quality control system specific for DUOX2.
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Affiliation(s)
- Helmut Grasberger
- Department of Medicine, The University of Chicago, 5841 South Maryland Avenue, Chicago, Illinois 60637, USA.
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26
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Howell GJ, Holloway ZG, Cobbold C, Monaco AP, Ponnambalam S. Cell biology of membrane trafficking in human disease. ACTA ACUST UNITED AC 2007; 252:1-69. [PMID: 16984815 PMCID: PMC7112332 DOI: 10.1016/s0074-7696(06)52005-4] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Understanding the molecular and cellular mechanisms underlying membrane traffic pathways is crucial to the treatment and cure of human disease. Various human diseases caused by changes in cellular homeostasis arise through a single gene mutation(s) resulting in compromised membrane trafficking. Many pathogenic agents such as viruses, bacteria, or parasites have evolved mechanisms to subvert the host cell response to infection, or have hijacked cellular mechanisms to proliferate and ensure pathogen survival. Understanding the consequence of genetic mutations or pathogenic infection on membrane traffic has also enabled greater understanding of the interactions between organisms and the surrounding environment. This review focuses on human genetic defects and molecular mechanisms that underlie eukaryote exocytosis and endocytosis and current and future prospects for alleviation of a variety of human diseases.
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Affiliation(s)
- Gareth J Howell
- Endothelial Cell Biology Unit, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, United Kingdom
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27
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Suzuki K. [Anti-neutrophil cytoplasmic antibody MPO-ANCA related with disease activity of vasculitis]. ACTA ACUST UNITED AC 2006; 29:94-101. [PMID: 16651707 DOI: 10.2177/jsci.29.94] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Myeloperoxidase (MPO)-specific anti-neutrophil cytoplasmic antibodies (MPO-ANCA) are involved in the development of vasculitis microscopic polyangiitis, a systemic vasculitis etc. We have showed a correlation of MPO-ANCA epitopes in vasculitis concerning contribution of N and C terminus of MPO to severity of the diseases. On the other hand, a role of activated neutrophils in inflammatory nephritis renal lesions using SCG/Kj mice. In the phase of nephritis with a low grade of proteinuria, the spontaneous release of MPO from peripheral neutrophils increased, indicating that neutrophils are activated and contribute to the development of active crescentic lesions in SCG/Kj mice. In addition, we have investigated that mice having CADS/CAWS-induced vasculitis also are good model animals for the analysis of the production of MPO-ANCA. Furthermore, we have clarified that MPO is a major antigen for MPO-ANCA production using MPO knock mice.
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Affiliation(s)
- Kazuo Suzuki
- Department of Bioactive Molecules, National Institute of Infectious Diseases
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28
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Persad AS, Kameoka Y, Kanda S, Niho Y, Suzuki K. Arginine to cysteine mutation (R499C) found in a Japanese patient with complete myeloperoxidase deficiency. Gene Expr 2006; 13:67-71. [PMID: 17017121 PMCID: PMC6032473 DOI: 10.3727/000000006783991863] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Animal models suggest that a deficiency in myeloperoxidase (MPO; EC 1.11.1.7), a lysosomal hemoprotein involved in host defense, may be associated with a decreased level of immunity. A nonsynonymous mutation, resulting in an arginine to cysteine substitution (Arg499Cys or R499C), has been identified in the exon 9 genetic coding region of a Japanese patient with complete MPO deficiency. Genetic analysis revealed that the mRNA of the patient could be correctly transcribed then further translated into a peptide sequence. However, the Western blot analysis confirmed the absence of MPO peptides. An initial screening assay of the patient's blood exhibited an abnormal hematograph, and no MPO activity was detected. To determine if this mutation might be associated with MPO deficiency, DNA samples for 387 controls were examined. Genetic analysis was performed using standard PCR techniques for amplification and sequencing. None of the control samples possessed the R499C substitution. This mutation is in close proximity to a different mutation (G501S) previously found in another Japanese MPO-deficient patient, and the amino acid, H502, which is strongly involved in heme binding, leading to the speculation that heme binding may play a role in complete MPO deficiency.
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Affiliation(s)
- Amanda S. Persad
- *Department of Bioactive Molecules, National Institute of Infectious Diseases, 1-23-1 Toyama, Shinjuku-ku, Tokyo 162-8640, Japan
| | - Yosuke Kameoka
- †Division of Genetic Resources, National Institute of Infectious Diseases, 1-23-1 Toyama, Shinjuku-ku, Tokyo 162-8640, Japan
| | | | | | - Kazuo Suzuki
- *Department of Bioactive Molecules, National Institute of Infectious Diseases, 1-23-1 Toyama, Shinjuku-ku, Tokyo 162-8640, Japan
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29
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Hansson M, Olsson I, Nauseef WM. Biosynthesis, processing, and sorting of human myeloperoxidase. Arch Biochem Biophys 2005; 445:214-24. [PMID: 16183032 DOI: 10.1016/j.abb.2005.08.009] [Citation(s) in RCA: 161] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2005] [Revised: 07/08/2005] [Accepted: 08/10/2005] [Indexed: 01/07/2023]
Abstract
Exclusively synthesized by normal neutrophil and monocyte precursor cells, myeloperoxidase (MPO) functions not only in host defense by mediating efficient microbial killing but also can contribute to progressive tissue damage in chronic inflammatory states such as atherosclerosis. The biosynthetic precursor, apoproMPO, is processed slowly in the ER, undergoing cotranslational N-glycosylation, transient interactions with the molecular chaperones calreticulin and calnexin, and heme incorporation to generate enzymatically active proMPO that is competent for export into the Golgi. After exiting the Golgi the propeptide is removed prior to final proteolytic processing in azurophil granules, resulting in formation of a symmetric MPO homodimer linked by a disulfide bond. Some proMPO escapes granule targeting and becomes constitutively secreted to the extracellular environment. Although the precise mechanism is unknown, the pro-segment is required for normal processing and targeting, as propeptide-deleted MPO precursor is either degraded or constitutively secreted. Characterizing the molecular consequences of naturally occurring mutations that cause inherited MPO deficiency provides unique insight into the structural determinants of MPO involved in biosynthesis, processing and targeting.
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Affiliation(s)
- Markus Hansson
- Department of Hematology, C14, BMC, SE-221 84 Lund, Sweden.
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30
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Marchetti C, Patriarca P, Solero GP, Baralle FE, Romano M. Genetic characterization of myeloperoxidase deficiency in Italy. Hum Mutat 2004; 23:496-505. [PMID: 15108282 DOI: 10.1002/humu.20027] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Hereditary myeloperoxidase (MPO) deficiency (MPOD) is the most common neutrophil biochemical defect, and is characterized by a lack of peroxidase activity. In order to extend the epidemiological studies on hereditary MPOD in Italy, a population screening was carried out to detect mutations in the MPO gene. Of approximately 40,000 individuals analyzed, seven partial and eight total MPO-deficient subjects were identified. The genetic characterization of the subjects showed the presence of three already-known mutations (c.752T>C, c.1705C>T, and c.1566_1579del14) and six novel mutations: four missense mutations (c.995C>T, c.1112A>G, c.1715T>G, and c.1927T>C), then a deletion of an adenine within exon 3 (c.325delA) and a mutation within the 3' splice site of intron 11 (c.2031-2A>C). The novel missense mutations cause the substitution of the residues p.A332V, p.D371G, p.L572W, and p.W643R, respectively, and the potential structural changes are discussed. The c.325delA deletion causes a shift of the reading frame with the occurrence of a premature stop codon within the propeptide. Then, considering the difficulty in obtaining bone marrow samples from MPO-deficient subjects to study MPO mRNA splicing in vivo, we set up an eukaryotic expression system to investigate how the c.2031-2A>C mutation alters the MPO pre-mRNA splicing. The activation of a cryptic 3' splice site located 109nt upstream of the authentic 3' splice site was observed. The 109nt-insertion causes a shift in the reading frame that should lead to the generation of an abnormal MPO precursor lacking the enzymatic activity.
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Affiliation(s)
- Caterina Marchetti
- International Centre for Genetic Engineering and Biotechnology, Trieste, Italy
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31
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Ohashi YY, Kameoka Y, Persad AS, Koi F, Yamagoe S, Hashimoto K, Suzuki K. Novel missense mutation found in a Japanese patient with myeloperoxidase deficiency. Gene 2004; 327:195-200. [PMID: 14980716 DOI: 10.1016/j.gene.2003.11.023] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2003] [Revised: 11/05/2003] [Accepted: 11/14/2003] [Indexed: 11/22/2022]
Abstract
Myeloperoxidase (MPO; EC 1.11.1.7) plays an important role in the host defense mechanism against microbial diseases. The neutrophil disorder characterized by the lack of MPO activity, is speculated to be associated with a decreased level of immunity. A Japanese patient was identified with complete MPO deficiency through automated hematography. Neutrophil function analysis revealed that MPO activity was significantly diminished with slightly elevated superoxide production. Mutational analysis of the patient revealed a glycine to serine substitution (G501S) in the exon 9 region. This mutation was not detected in the 96 healthy controls analyzed. The amino acid substitution found may be responsible for the failure of mature MPO production in the patient. This is the first case of MPO deficiency of G501S missense mutation identified in a Japanese patient.
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Affiliation(s)
- Yuko Y Ohashi
- Department of Bioactive Molecules, National Institute of Infectious Diseases, 1-23-1 Toyama, Shinjuku, Tokyo 162-8640, Japan
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32
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Morgan RR, Errington R, Elder GH. Identification of sequences required for the import of human protoporphyrinogen oxidase to mitochondria. Biochem J 2004; 377:281-7. [PMID: 14535846 PMCID: PMC1223874 DOI: 10.1042/bj20030978] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2003] [Revised: 09/26/2003] [Accepted: 10/10/2003] [Indexed: 11/17/2022]
Abstract
Protoporphyrinogen oxidase (PPOX; EC 1.3.3.4), the penultimate enzyme of haem biosynthesis, is a nucleus-encoded flavoprotein strongly associated with the outer surface of the inner mitochondrial membrane. It is attached to this membrane by an unknown mechanism that appears not to involve a membrane-spanning domain. The pathway for its import to mitochondria and insertion into the inner membrane has not been established. We have fused human PPOXs containing N-terminal deletions, C-terminal deletions or missense mutations to yellow fluorescent protein (YFP) and have used these constructs to investigate the mitochondrial import of PPOX in human cells. We show that all the information required for efficient import is contained within the first 250 amino acid residues of human PPOX and that targeting to mitochondria is prevented by fusion of YFP to the N-terminus. Deletion of between 151 and 175 residues from the N-terminus is required to abolish import, whereas shorter deletions impair its efficiency. Fully efficient targeting appears to require both a major targeting signal, the whole or part of which is contained between residues 151 and 175, and which may be involved in anchoring to the inner mitochondrial membrane, together with interaction between this region and a sequence(s) within the first 150 residues. These features suggest that the mechanism for import of human PPOX to mitochondria differs from those identified for the translocation of nucleus-encoded, membrane-spanning, inner membrane proteins. In addition, a missense mutation outside this region (Val(335)-->Gly) prevented targeting to mitochondria and delayed the appearance of YFP fluorescence. This mutation appeared to prevent import by a direct effect on protein folding rather than by altering a sequence required for targeting. It may lead to sequestration of the PPOX-YFP construct in an unfolded conformation, followed by proteolytic degradation, possibly through enhanced binding to a cytosolic chaperone protein.
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Affiliation(s)
- Rhian R Morgan
- Department of Medical Biochemistry and Immunology, University of Wales College of Medicine, Heath Park, Cardiff CF14 4XN, UK
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33
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Abstract
In glomerular and tubulointerstitial disease, polymorphonuclear- and monocyte-derived reactive oxygen species may contribute to oxidative modification of proteins, lipids, and nucleic acids. In part, the processes instigated by reactive oxygen species parallel events that lead to the development of atherosclerosis. Myeloperoxidase (MPO), a heme protein and catalyst for (lipo)protein oxidation is present in these mononuclear cells. The ability of MPO to generate hypochlorous acid/hypochlorite (HOCl/OCl-) from hydrogen peroxide in the presence of chloride ions is a unique and defining activity for this enzyme. The MPO-hydrogen peroxide-chloride system leads to a variety of chlorinated protein and lipid adducts that in turn may cause dysfunction of cells in different compartments of the kidney. The aim of this article is to cover and interpret some experimental and clinical aspects in glomerular and tubulointerstitial diseases in which the MPO-hydrogen peroxide-chloride system has been considered an important pathophysiologic factor in the progression but also the attenuation of experimental renal disease. The colocalization of MPO and HOCl-modified proteins in glomerular peripheral basement membranes and podocytes in human membranous glomerulonephritis, the presence of HOCl-modified proteins in mononuclear cells of the interstitium and in damaged human tubular epithelia, the inflammation induced and exacerbated by MPO antibody complexes in necrotizing glomerulonephritis, and the presence of HOCl-modified epitopes in urine following hyperlipidemia-induced renal damage in rodents suggest that MPO is an important pathogenic factor in glomerular and tubulointerstitial diseases. Specifically, the interaction of MPO with nitric oxide metabolism adds to the complexity of actions of oxidants and may help to explain bimodal partly detrimental partly beneficial effects of the MPO-hydrogen peroxide-chloride system in redox-modulated renal diseases.
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Affiliation(s)
- Ernst Malle
- Karl-Franzens University Graz, Institute of Medical Biochemistry and Molecular Biology, Graz, Austria
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34
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Chevrier I, St??cker I, Houllier AM, Cen??e S, Beaune P, Laurent-Puig P, Loriot MA. Myeloperoxidase. ACTA ACUST UNITED AC 2003. [DOI: 10.1097/00008571-200312000-00004] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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35
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McCracken AA, Brodsky JL. Evolving questions and paradigm shifts in endoplasmic-reticulum-associated degradation (ERAD). Bioessays 2003; 25:868-77. [PMID: 12938176 DOI: 10.1002/bies.10320] [Citation(s) in RCA: 169] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
ER-associated degradation (ERAD) is a component of the protein quality control system, ensuring that aberrant polypeptides cannot transit through the secretory pathway. This is accomplished by a complex sequence of events in which unwanted proteins are selected in the ER and exported to the cytosol for degradation by the proteasome. Given that protein quality control can be essential for cell survival, it is not surprising that ERAD is linked to numerous disease states. Here we review the molecular mechanisms of ERAD, its role in metabolic regulation and biomedical implications, and the unanswered questions regarding this process.
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36
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Reumaux D, de Boer M, Meijer AB, Duthilleul P, Roos D. Expression of myeloperoxidase (MPO) by neutrophils is necessary for their activation by anti-neutrophil cytoplasm autoantibodies (ANCA) against MPO. J Leukoc Biol 2003; 73:841-9. [PMID: 12773517 DOI: 10.1189/jlb.1102567] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Anti-neutrophil cytoplasm autoantibodies (ANCA) directed against proteinase-3 and myeloperoxidase (MPO) activate tumor necrosis factor-alpha-primed neutrophils in vitro. We used neutrophils from one completely and one partially MPO-deficient donor to assess the requirement of MPO expression for neutrophil activation by anti-MPO antibodies. The MPO deficiencies were defined enzymatically, by immunocytochemistry and by immunoblotting. The mutations in the MPO genes of these donors were identified as a combination of a novel splice-site mutation at the 3' end of intron 11 (A-2-->C), a deletion of 14 nucleotides in exon 9 (A1555-C1568), and a novel C1907 --> T (636Thr-->Met) substitution in exon 11 in the completely MPO-deficient donor and as the same splice-site mutation and a novel C995 --> T (332Ala-->Val) substitution in exon 7 in the partially MPO-deficient donor. Monoclonal antibody 4.15 against MPO and MPO-ANCA-immunoglobulin G induced no superoxide anion production in these MPO-deficient neutrophils despite a normal production induced by other stimuli. Thus, the presence of MPO is a conditio sine qua non for neutrophil activation by anti-MPO antibodies. Moreover, we demonstrated that by means of these MPO-deficient cells, hydrogen peroxide may diffuse from neutrophils to surrounding cells, which may contribute to the damage induced by oxygen radicals in the pathology of systemic vasculitides.
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Affiliation(s)
- Dominique Reumaux
- Département d'Hématologie-Immunologie-Cytogénétique, Centre Hospitalier de Valenciennes, France.
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37
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Clements MK, Siemsen DW, Swain SD, Hanson AJ, Nelson-Overton LK, Rohn TT, Quinn MT. Inhibition of actin polymerization by peroxynitrite modulates neutrophil functional responses. J Leukoc Biol 2003; 73:344-55. [PMID: 12629148 DOI: 10.1189/jlb.0802401] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Peroxynitrite, a potent oxidant generated in inflammatory tissues, can nitrate tyrosine residues on a variety of proteins. Based on previous studies suggesting that actin might be a potential target for peroxynitrite-mediated nitration in neutrophils, we investigated the effects of peroxynitrite on actin function. We show here that peroxynitrite and the peroxynitrite generator (SIN-1) modified actin in a concentration-dependent manner, resulting in an inhibition of globular-actin polymerization and filamentous-actin depolymerization in vitro. The effects of peroxynitrite were inhibited by the pyrrolopyrimidine antioxidant PNU-101033E, which has been shown previously to specifically block peroxynitrite-mediated tyrosine nitration. Furthermore, spectrophotometric and immunoblot analysis of peroxynitrite-treated actin demonstrated a concentration-dependent increase in nitrotyrosine, which was also blocked by PNU-101033E. Activation of neutrophils in the presence of a nitric oxide donor (S-nitroso-N-acetylpenicillamine) resulted in nitration of exogenously added actin. Nitrated actin was also found in peroxynitrite-treated neutrophils, suggesting that actin may be an important intracellular target during inflammation. To investigate this issue, we analyzed the effect of peroxynitrite treatment on a number of actin-dependent neutrophil processes. Indeed, neutrophil actin polymerization, migration, phagocytosis, and respiratory burst activity were all inhibited by SIN-1 treatment in a concentration-dependent manner. Therefore, the ability of peroxynitrite to inhibit actin dynamics has a significant effect on actin-dependent, cellular processes in phagocytic cells and may modulate their host defense function.
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Affiliation(s)
- Mark K Clements
- Department of Veterinary Molecular Biology, Montana State University, Bozeman, 59717, USA
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38
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Bostan M, Galatiuc C, Hirt M, Constantin MC, Brasoveanu LI, Iordachescu D. Phospholipase A2 modulates respiratory burst developed by neutrophils in patients with rheumatoid arthritis. J Cell Mol Med 2003; 7:57-66. [PMID: 12767262 PMCID: PMC6740302 DOI: 10.1111/j.1582-4934.2003.tb00203.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
Abstract
Activated by bacterial peptides, phorbol esters, calcium ionophores and other agonists, neutrophils (PMNs) release the proinflammatory mediator, arachidonic acid (AA) via the intervention of phospholipase A(2) (PLA(2)). AA may play an essential role in activation of NADPH-oxidase, which is involved in the generation of superoxide anion by neutrophils. The present study is focused on the involvement of PLA(2) in the respiratory burst developed by PMNs isolated from patients with rheumatoid arthritis (RA). PLA(2) exists in very high levels in diseases such as rheumatoid arthritis and may cause acute inflammatory and proliferative changes in synovial structures. The respiratory burst was evaluated as superoxide anion release, using an amplified chemiluminescence method. The assays were performed using PMNs untreated or treated with different doses of stimulatory reagents (phorbol 12-myristate-13-acetate (PMA), calcium ionophore (A23187)). Our data suggested that PMA stimulated the production of superoxide anion in a dose-response manner, as compared with A23187, which did not induce a significant release of superoxide anion in PMNs-RA. The exogenous addition of AA significantly amplified the superoxide anion release by PMNs-RA stimulated with PMA and to a lesser extent, by PMNs stimulated with A23187. AA has also reversed the inhibitory effect of arachidonyl-trifluorometylketone and E-6-(bromomethylene)tetrahydro-3-(1-naphthalenyl)2H-pyran-2-one (BEL) on the superoxide anion release by PMNs-RA. In conclusion, the differential responses to these two agents suggested that different isoforms of PLA(2) were activated by A23187 or PMA, and support the idea that activation of these different PLA(2) served distinct functions of PMNs. Therefore, the inhibition of PLA(2) enzymes might be of great importance in the immunotherapy of rheumatoid arthritis.
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Affiliation(s)
- Marinela Bostan
- Center of Immunology, Stefan S. Nicolau Institute of Virology, Bucharest, Romania.
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39
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Aratani Y, Kura F, Watanabe H, Akagawa H, Takano Y, Suzuki K, Dinauer MC, Maeda N, Koyama H. Relative contributions of myeloperoxidase and NADPH-oxidase to the early host defense against pulmonary infections with Candida albicans and Aspergillus fumigatus. Med Mycol 2002; 40:557-63. [PMID: 12521119 DOI: 10.1080/mmy.40.6.557.563] [Citation(s) in RCA: 107] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
Abstract
Generation of oxidative products by phagocytic cells is known to be an important host defense mechanism directed toward killing of invading microorganisms. The importance of two major oxidant-producing enzymes, myeloperoxidase (MPO) and NADPH-oxidase, in in vivo fungicidal action was directly compared in genetically engineered mice. Both MPO-deficient (MPO-/-) and NADPH-oxidase-deficient (X-linked chronic granulomatous disease [X-CGD]) mice showed increased susceptibility to pulmonary infections with Candida albicans and Aspergillus fumigatus compared with normal mice, and the X-CGD mice exhibited shorter survivals than MPO-/- mice. This increased mortality of X-CGD mice was associated with a 10- to 100-fold increased outgrowth of the fungi in their organs during the first 6 days. These results suggest that superoxide (O2-) produced by NADPH-oxidase is more important than hypochlorous acid (HOCl) produced by MPO, although both oxidative products obviously contribute to the host defense against pulmonary infection with those fungi. We also observed that MPO-/-/X-CGD double knockout mice showed comparable levels of susceptibility to the X-CGD mice against C. albicans and A. funigatus, indicating that MPO is unable to play a role in host defense in the absence of NADPH-oxidase. This strongly suggests that hydrogen peroxide, the precursor of HOCl, is solely derived from O2- produced by NADPH-oxidase.
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Affiliation(s)
- Y Aratani
- Kihara Institute for Biological Research, Yokohama City University, Maioka-cho 641-12, Totsuka, Yokohama 244-0813, Japan.
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40
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Lin SJ, Huang YF, Chen JY, Heyworth PG, Noack D, Wang JY, Lin CY, Chiang BL, Yang CM, Liu CC, Shieh CC. Molecular quality control machinery contributes to the leukocyte NADPH oxidase deficiency in chronic granulomatous disease. BIOCHIMICA ET BIOPHYSICA ACTA 2002; 1586:275-86. [PMID: 11997079 DOI: 10.1016/s0925-4439(01)00106-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Chronic granulomatous disease (CGD) is an inherited immunodeficiency disease caused by defects in leukocyte NADPH oxidase. Various inherited defects in one of the membrane-bound components of NADPH oxidase, gp91-phox, cause X-linked (X91) CGD. Analysis of three patients with X91 CGD revealed that different mechanisms of molecular quality control lead to the common phenotype of absence of mature membrane-bound NADPH oxidase complex in leukocytes. In the first patient, aberrant intron splicing created a premature stop codon. However, the mutant mRNA was degraded prematurely, which prevented the production of truncated protein. In the second patient, a frameshift mutation with the potential to generate a gp91-phox polypeptide, with an aberrant and elongated C-terminus, led to barely detectable levels of gp91-phox, even though the reported functional domains of the protein appeared unaffected. In the third patient, a point mutation created a single amino acid change in the predicted FAD-binding site of gp91-phox. Although gp91-phox was detectable with Western blotting, no cytochrome b(558) was expressed on the cell surface. These analyses showed that molecular quality control machinery plays an important role in the pathogenesis of CGD, not only in the X910 but also in the X91- form of this X-linked disease.
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Affiliation(s)
- Shio-Jean Lin
- Department of Pediatrics, National Cheng-Kung University, 138 Sheng-Li Rd, Tainan 704, Taiwan
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41
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Bülow E, Nauseef WM, Goedken M, McCormick S, Calafat J, Gullberg U, Olsson I. Sorting for storage in myeloid cells of nonmyeloid proteins and chimeras with the propeptide of myeloperoxidase precursor. J Leukoc Biol 2002. [DOI: 10.1189/jlb.71.2.279] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Affiliation(s)
- E. Bülow
- Department of Hematology, Lund University, Sweden
| | - W. M. Nauseef
- Inflammation Program and Department of Medicine, Veterans Administration Medical Center and University of Iowa, Iowa City; and
| | - M. Goedken
- Inflammation Program and Department of Medicine, Veterans Administration Medical Center and University of Iowa, Iowa City; and
| | - S. McCormick
- Inflammation Program and Department of Medicine, Veterans Administration Medical Center and University of Iowa, Iowa City; and
| | - J. Calafat
- The Netherlands Cancer Institute, Amsterdam
| | - U. Gullberg
- Department of Hematology, Lund University, Sweden
| | - I. Olsson
- Department of Hematology, Lund University, Sweden
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42
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Hoy A, Leininger-Muller B, Kutter D, Siest G, Visvikis S. Growing significance of myeloperoxidase in non-infectious diseases. Clin Chem Lab Med 2002; 40:2-8. [PMID: 11916266 DOI: 10.1515/cclm.2002.002] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Myeloperoxidase (MPO) is a glycoprotein released by activated polymorphonuclear neutrophils, which takes part in the defense of the organism through production of hypochlorous acid (HOCl), a potent oxidant. Since the discovery of MPO deficiency, initially regarded as rare and restricted to patients suffering from severe infections, MPO has attracted clinical attention. The development of new technologies allowing screening for this defect has permitted new advances in the comprehension of underlying mechanisms. Apart from its implications for host defense, the expression of MPO restricted to myeloid precursors makes MPO mRNA a good marker of acute myeloid leukemia. In addition, during the last few years, involvement of MPO has been described in numerous diseases such as atherosclerosis, lung cancer, Alzheimer's disease and multiple sclerosis. Both strong oxidative activity and MPO genetic polymorphism have been involved. This review summarizes the broad range of diseases involving MPO and points out the possible use of this protein as a new clinical marker and a future therapeutic target.
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Affiliation(s)
- Aline Hoy
- INSERM Unité 525 Faculté de Pharmacie, Nancy, France
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43
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Abstract
This review highlights the various numerical and functional defects in the phagocyte system. It mainly focuses on newly discovered genetic defects in the system and the role played by these defects in the clinical symptoms presented by patients. Novel therapeutic modalities to treat phagocyte abnormalities, which are currently under clinical trials, are also discussed.
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Affiliation(s)
- A Etzioni
- Department of Pediatrics, Rambam Medical Centre and B. Rappaport School of Medicine, Technion, Haifa, Israel.
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44
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Hoy A, Trégouët D, Leininger-Muller B, Poirier O, Maurice M, Sass C, Siest G, Tiret L, Visvikis S. Serum myeloperoxidase concentration in a healthy population: biological variations, familial resemblance and new genetic polymorphisms. Eur J Hum Genet 2001; 9:780-6. [PMID: 11781690 DOI: 10.1038/sj.ejhg.5200702] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2001] [Revised: 06/08/2001] [Accepted: 06/29/2001] [Indexed: 02/02/2023] Open
Abstract
Myeloperoxidase (MPO) has been involved in the pathogenesis of several diseases through excessive production of reactive oxygen species (ROS) as well as through its genetic polymorphism. The aims of this study were to identify the factors affecting MPO serum concentration, to study the familial resemblance of MPO levels and to investigate the association between newly described MPO polymorphisms as well as the G-463A one and MPO levels in a healthy population. MPO serum concentrations were measured by an enzymatic immuno-assay (EIA) in 82 healthy families of the STANISLAS Cohort and MPO genotype, determination was performed using PCR-restriction fragment length polymorphism or allele specific oligonucleotide assay. MPO concentrations were significantly higher in parents than in offspring. The factors affecting MPO levels were age, the number of white cells, smoking in fathers and oral contraceptive intake in mothers. They explain from 12.4% up to 35.9% of MPO variability in men and women, respectively. Family correlations of MPO concentrations were of similar magnitude. The -129A allele of a newly described G-129A substitution was significantly associated with decreased MPO levels, whereas the -463A allele was suggested to be associated with increased levels of lipid variables. In this study, we identified factors affecting MPO serum concentrations and showed that molecular variations of the gene have only a weak influence on MPO variability. In contrast, the association between the G-463A polymorphism and lipid levels would suggest a possible implication of MPO in the risk of cardiovascular diseases. These results have to be confirmed and further investigations will be conducted in that way.
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Affiliation(s)
- A Hoy
- Faculté de Pharmacie, INSERM Unité 525, Nancy, France
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45
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Nauseef WM, McCormick S, Goedken M. Impact of missense mutations on biosynthesis of myeloperoxidase. Redox Rep 2001; 5:197-206. [PMID: 10994874 DOI: 10.1179/135100000101535753] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
We have examined the biosynthesis of normal and mutant forms of myeloperoxidase (MPO) in order to gain insights into the critical features of normal biogenesis of MPO. The expression of wild-type and mutant forms of MPO in a stably transfected cell line devoid of endogenous MPO as well as in established human promyelocytic cell lines has allowed understanding of several features of MPO biosynthesis. It is clear that heme insertion into apoproMPO is necessary for proper folding, egress from the endoplasmic reticulum (ER), and eventual entry into the maturation pathway. In addition, molecular chaperones calreticulin and calnexin interact with normal MPO precursors in a sequential and regulated fashion. Studies of naturally occurring mutants, specifically missense mutations underlying inherited MPO deficiency, and mutations in putatively important residues in MPO have highlighted special features of the ER quality control system in the context of MPO biosynthesis. With identification of additional genotypes of MPO deficiency and the recent solution of MPO crystal structure at 1.8 A, this approach provides a powerful technique to assess structure-function relationships in MPO that are likely applicable to other members of the family of animal peroxidases.
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Affiliation(s)
- W M Nauseef
- Inflammation Program and Department of Medicine, University of Iowa, and Veterans Affairs Medical Center at Iowa City, 52422, USA.
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Bülow E, Gullberg U, Olsson I. Structural requirements for intracellular processing and sorting of bactericidal/permeability‐increasing protein (BPI): comparison with lipopolysaccharide‐binding protein. J Leukoc Biol 2000. [DOI: 10.1189/jlb.68.5.669] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Affiliation(s)
- Elinor Bülow
- Department of Hematology, Research Department 2, University Hospital, Lund, Sweden
| | - Urban Gullberg
- Department of Hematology, Research Department 2, University Hospital, Lund, Sweden
| | - Inge Olsson
- Department of Hematology, Research Department 2, University Hospital, Lund, Sweden
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Abstract
As sequencing of the human genome nears completion, the genes that cause many human diseases are being identified and functionally described. This has revealed that many human diseases are due to defects of intracellular trafficking. This 'Toolbox' catalogs and briefly describes these diseases.
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Affiliation(s)
- M Aridor
- Department of Cell Biology and Physiology, University of Pittsburgh, School of Medicine, 3500 Terrace St, Pittsburgh, PA 15261, USA
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48
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A novel von Willebrand disease–causing mutation (Arg273Trp) in the von Willebrand factor propeptide that results in defective multimerization and secretion. Blood 2000. [DOI: 10.1182/blood.v96.2.560.014k01_560_568] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In this report we describe the molecular defect underlying partial and severe quantitative von Willebrand factor (VWF) deficiencies in 3 families previously diagnosed with types 1 and 3 Von Willebrand-disease. Analysis of the VWF gene in affected family members revealed a novel C to T transition at nucleotide 1067 of the VWF complemetary DNA (cDNA), predicting substitution of arginine by tryptophan at amino acid position 273 (R273W) of pre–pro-VWF. Two patients, homozygous for the R273W mutation, had a partial VWF deficiency (VWF:Ag levels of 0.06 IU/mL and 0.09 IU/mL) and lacked high-molecular weight VWF multimers in plasma. A third patient, also homozygous for the R273W mutation, had a severe VWF deficiency (VWF:Ag level of less than 0.01 IU/mL) and undetectable VWF multimers in plasma. Recombinant VWF having the R273W mutation was expressed in COS-7 cells. Pulse-chase experiments showed that secretion of rVWFR273W was severely impaired compared with wild-type rVWF. However, the mutation did not affect the ability of VWF to form dimers in the endoplasmic reticulum (ER). Multimer analysis showed that rVWFR273W failed to form high-molecular-weight multimers present in wild-type rVWF. We concluded that the R273W mutation is responsible for the quantitative VWF deficiencies and aberrant multimer patterns observed in the affected family members. To identify factors that may function in the intracellular retention of rVWFR273W, we investigated the interactions of VWF expressed in COS-7 cells with molecular chaperones of the ER. The R273W mutation did not affect the ability of VWF to bind to BiP, Grp94, ERp72, calnexin, and calreticulin in COS-7 cells.
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49
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A novel von Willebrand disease–causing mutation (Arg273Trp) in the von Willebrand factor propeptide that results in defective multimerization and secretion. Blood 2000. [DOI: 10.1182/blood.v96.2.560] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
AbstractIn this report we describe the molecular defect underlying partial and severe quantitative von Willebrand factor (VWF) deficiencies in 3 families previously diagnosed with types 1 and 3 Von Willebrand-disease. Analysis of the VWF gene in affected family members revealed a novel C to T transition at nucleotide 1067 of the VWF complemetary DNA (cDNA), predicting substitution of arginine by tryptophan at amino acid position 273 (R273W) of pre–pro-VWF. Two patients, homozygous for the R273W mutation, had a partial VWF deficiency (VWF:Ag levels of 0.06 IU/mL and 0.09 IU/mL) and lacked high-molecular weight VWF multimers in plasma. A third patient, also homozygous for the R273W mutation, had a severe VWF deficiency (VWF:Ag level of less than 0.01 IU/mL) and undetectable VWF multimers in plasma. Recombinant VWF having the R273W mutation was expressed in COS-7 cells. Pulse-chase experiments showed that secretion of rVWFR273W was severely impaired compared with wild-type rVWF. However, the mutation did not affect the ability of VWF to form dimers in the endoplasmic reticulum (ER). Multimer analysis showed that rVWFR273W failed to form high-molecular-weight multimers present in wild-type rVWF. We concluded that the R273W mutation is responsible for the quantitative VWF deficiencies and aberrant multimer patterns observed in the affected family members. To identify factors that may function in the intracellular retention of rVWFR273W, we investigated the interactions of VWF expressed in COS-7 cells with molecular chaperones of the ER. The R273W mutation did not affect the ability of VWF to bind to BiP, Grp94, ERp72, calnexin, and calreticulin in COS-7 cells.
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50
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Romano M, Baralle FE, Patriarca P. Expression and characterization of recombinant human eosinophil peroxidase. Impact of the R286H substitution on the biosynthesis and activity of the enzyme. EUROPEAN JOURNAL OF BIOCHEMISTRY 2000; 267:3704-11. [PMID: 10848988 DOI: 10.1046/j.1432-1327.2000.01403.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Hereditary eosinophil peroxidase deficiency is a genetic abnormality characterized by a decrease or absence of peroxidase activity and a reduction of the granule matrix volume. Recently, we identified two mutations associated with eosinophil peroxidase deficiency in a subject and his siblings, i.e. a base insertion causing the appearance of a premature stop codon and a base transition causing the replacement of an Arg at codon 286 with a His (R286H). In this article we report the stable expression of both the recombinant wild-type and the R286H eosinophil peroxidase precursor in the K-562 cell line, and the effects of the R286H substitution on the structure and function of the eosinophil peroxidase precursor. Heme group incorporation into both the recombinant wild-type and the recombinant R286H eosinophil peroxidase precursor was comparable, as was the stability of both proteins. Instead, the recombinant R286H eosinophil peroxidase precursor exhibited marked alterations of the catalytic properties and an increased sensitivity to four peroxidase inhibitors with respect to both the recombinant wild-type eosinophil peroxidase precursor and the native enzyme. In addition, the recombinant wild-type, but not the R286H, eosinophil peroxidase precursor was immunoprecipitated by two anti-(eosinophil peroxidase) mAbs. Altogether, our results suggest a protein misfolding of the R286H eosinophil peroxidase precursor which might account for its altered catalytic properties and the absence of expression of some epitopes.
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Affiliation(s)
- M Romano
- International Center for Genetic Engineering an Biotechnology, Trieste, Italy.
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