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Boginskaya I, Safiullin R, Tikhomirova V, Kryukova O, Nechaeva N, Bulaeva N, Golukhova E, Ryzhikov I, Kost O, Afanasev K, Kurochkin I. Human Angiotensin I-Converting Enzyme Produced by Different Cells: Classification of the SERS Spectra with Linear Discriminant Analysis. Biomedicines 2022; 10:biomedicines10061389. [PMID: 35740411 PMCID: PMC9219671 DOI: 10.3390/biomedicines10061389] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Revised: 06/07/2022] [Accepted: 06/09/2022] [Indexed: 11/16/2022] Open
Abstract
Angiotensin I-converting enzyme (ACE) is a peptidase widely presented in human tissues and biological fluids. ACE is a glycoprotein containing 17 potential N-glycosylation sites which can be glycosylated in different ways due to post-translational modification of the protein in different cells. For the first time, surface-enhanced Raman scattering (SERS) spectra of human ACE from lungs, mainly produced by endothelial cells, ACE from heart, produced by endothelial heart cells and miofibroblasts, and ACE from seminal fluid, produced by epithelial cells, have been compared with full assignment. The ability to separate ACEs’ SERS spectra was demonstrated using the linear discriminant analysis (LDA) method with high accuracy. The intervals in the spectra with maximum contributions of the spectral features were determined and their contribution to the spectrum of each separate ACE was evaluated. Near 25 spectral features forming three intervals were enough for successful separation of the spectra of different ACEs. However, more spectral information could be obtained from analysis of 50 spectral features. Band assignment showed that several features did not correlate with band assignments to amino acids or peptides, which indicated the carbohydrate contribution to the final spectra. Analysis of SERS spectra could be beneficial for the detection of tissue-specific ACEs.
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Affiliation(s)
- Irina Boginskaya
- Institute for Theoretical and Applied Electromagnetics RAS, 125412 Moscow, Russia; (R.S.); (I.R.); (K.A.)
- Bakulev Scientific Center for Cardiovascular Surgery, Cardiology Department, 121552 Moscow, Russia; (N.B.); (E.G.)
- Correspondence:
| | - Robert Safiullin
- Institute for Theoretical and Applied Electromagnetics RAS, 125412 Moscow, Russia; (R.S.); (I.R.); (K.A.)
- Moscow Institute of Physics and Technology, 141700 Dolgoprudny, Russia
| | - Victoria Tikhomirova
- Faculty of Chemistry, M.V. Lomonosov Moscow State University, 119991 Moscow, Russia; (V.T.); (O.K.); (O.K.); (I.K.)
| | - Olga Kryukova
- Faculty of Chemistry, M.V. Lomonosov Moscow State University, 119991 Moscow, Russia; (V.T.); (O.K.); (O.K.); (I.K.)
| | - Natalia Nechaeva
- Emanuel Institute of Biochemical Physics RAS, 119334 Moscow, Russia;
| | - Naida Bulaeva
- Bakulev Scientific Center for Cardiovascular Surgery, Cardiology Department, 121552 Moscow, Russia; (N.B.); (E.G.)
| | - Elena Golukhova
- Bakulev Scientific Center for Cardiovascular Surgery, Cardiology Department, 121552 Moscow, Russia; (N.B.); (E.G.)
| | - Ilya Ryzhikov
- Institute for Theoretical and Applied Electromagnetics RAS, 125412 Moscow, Russia; (R.S.); (I.R.); (K.A.)
- FMN Laboratory, Bauman Moscow State Technical University, 105005 Moscow, Russia
| | - Olga Kost
- Faculty of Chemistry, M.V. Lomonosov Moscow State University, 119991 Moscow, Russia; (V.T.); (O.K.); (O.K.); (I.K.)
| | - Konstantin Afanasev
- Institute for Theoretical and Applied Electromagnetics RAS, 125412 Moscow, Russia; (R.S.); (I.R.); (K.A.)
| | - Ilya Kurochkin
- Faculty of Chemistry, M.V. Lomonosov Moscow State University, 119991 Moscow, Russia; (V.T.); (O.K.); (O.K.); (I.K.)
- Emanuel Institute of Biochemical Physics RAS, 119334 Moscow, Russia;
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Popova IA, Lubbe L, Petukhov PA, Kalantarov GF, Trakht IN, Chernykh ER, Leplina OY, Lyubimov AV, Garcia JGN, Dudek SM, Sturrock ED, Danilov SM. Epitope mapping of novel monoclonal antibodies to human angiotensin I-converting enzyme. Protein Sci 2021; 30:1577-1593. [PMID: 33931897 DOI: 10.1002/pro.4091] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Revised: 04/16/2021] [Accepted: 04/23/2021] [Indexed: 12/19/2022]
Abstract
Angiotensin I-converting enzyme (ACE, CD143) plays a crucial role in blood pressure regulation, vascular remodeling, and immunity. A wide spectrum of mAbs to different epitopes on the N and C domains of human ACE have been generated and used to study different aspects of ACE biology, including establishing a novel approach-conformational fingerprinting. Here we characterized a novel set of 14 mAbs, developed against human seminal fluid ACE. The epitopes for these novel mAbs were defined using recombinant ACE constructs with truncated N and C domains, species cross-reactivity, ACE mutagenesis, and competition with the previously mapped anti-ACE mAbs. Nine mAbs recognized regions on the N domain, and 5 mAbs-on the C domain of ACE. The epitopes for most of these novel mAbs partially overlap with epitopes mapped onto ACE by the previously generated mAbs, whereas mAb 8H1 recognized yet unmapped region on the C domain where three ACE mutations associated with Alzheimer's disease are localized and is a marker for ACE mutation T877M. mAb 2H4 could be considered as a specific marker for ACE in dendritic cells. This novel set of mAbs can identify even subtle changes in human ACE conformation caused by tissue-specific glycosylation of ACE or mutations, and can detect human somatic and testicular ACE in biological fluids and tissues. Furthermore, the high reactivity of these novel mAbs provides an opportunity to study changes in the pattern of ACE expression or glycosylation in different tissues, cells, and diseases, such as sarcoidosis and Alzheimer's disease.
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Affiliation(s)
- Isolda A Popova
- Recombinant Protein Production Core (rPPC), Chemistry of Life Processes Institute, Northwestern University, Evanston, Illinois, USA
| | - Lizelle Lubbe
- Department of Integrative Biomedical Sciences, Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Cape Town, South Africa
| | - Pavel A Petukhov
- School of Pharmacy, University of Illinois, Chicago, Illinois, USA
| | | | - Ilya N Trakht
- Department of Medicine, Columbia University, New York, New York, USA
| | - Elena R Chernykh
- Laboratory of Cellular Immunotherapy, Institute of Fundamental and Clinical Immunology, Novosibirsk, Russia
| | - Olga Y Leplina
- Laboratory of Cellular Immunotherapy, Institute of Fundamental and Clinical Immunology, Novosibirsk, Russia
| | - Alex V Lyubimov
- Toxicology Research Laboratory, University of Illinois, Chicago, Illinois, USA
| | - Joe G N Garcia
- Department of Medicine, University of Arizona, Tucson, Arizona, USA
| | - Steven M Dudek
- Division of Pulmonary, Critical Care, Sleep and Allergy, Department of Medicine, University of Illinois, Chicago, Illinois, USA
| | - Edward D Sturrock
- Department of Integrative Biomedical Sciences, Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Cape Town, South Africa
| | - Sergei M Danilov
- Department of Medicine, University of Arizona, Tucson, Arizona, USA.,Division of Pulmonary, Critical Care, Sleep and Allergy, Department of Medicine, University of Illinois, Chicago, Illinois, USA.,Medical Center, Moscow University, Moscow, Russia
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3
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Novel ACE mutations mimicking sarcoidosis by increasing blood ACE levels. Transl Res 2021; 230:5-20. [PMID: 32726712 DOI: 10.1016/j.trsl.2020.07.010] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Revised: 07/20/2020] [Accepted: 07/23/2020] [Indexed: 11/22/2022]
Abstract
An elevated blood angiotensin I-converting enzyme (ACE) supports diagnosis of sarcoidosis and Gaucher disease. However, some ACE mutations increase ACE shedding, and patients with these mutations are therefore at risk of being incorrectly diagnosed with sarcoidosis because of elevated serum ACE levels. We applied a novel approach called "ACE phenotyping" to identify possible ACE mutations in 3 pulmonary clinic patients that had suspected sarcoidosis based on elevated blood ACE levels. Conformational fingerprinting of ACE indicated that these mutations may be localized in the stalk region of the protein and these were confirmed by whole exome sequencing. Index patient 1 (IP1) had a mutation (P1199L) that had been previously identified, while the other 2 patients had novel ACE mutations. IP2 had 2 mutations, T887M and N1196K (eliminating a putative glycosylation site), while IP3 had a stop codon mutation Q1124X (eliminating the transmembrane anchor). We also performed a comprehensive analysis of the existing database of all ACE mutations to estimate the proportion of mutations increasing ACE shedding. The frequency of ACE mutations resulting in increased blood ACE levels may be much higher than previously estimated. ACE phenotyping, together with whole exome sequencing, is a diagnostic approach that could prevent unnecessary invasive and/or costly diagnostic procedures, or potentially harmful treatment for patients misdiagnosed on the basis of elevated blood ACE levels.
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Abstract
Background Pulmonary vascular endothelium is the main metabolic site for Angiotensin I-Converting Enzyme (ACE)-mediated degradation of several biologically-active peptides (angiotensin I, bradykinin, hemo-regulatory peptide Ac-SDKP). Primary lung cancer growth and lung cancer metastases decrease lung vascularity reflected by dramatic decreases in both lung and serum ACE activity. We performed precise ACE phenotyping in tissues from subjects with lung cancer. Methodology ACE phenotyping included: 1) ACE immunohistochemistry with specific and well-characterized monoclonal antibodies (mAbs) to ACE; 2) ACE activity measurement with two ACE substrates (HHL, ZPHL); 3) calculation of ACE substrates hydrolysis ratio (ZPHL/HHL ratio); 4) the pattern of mAbs binding to 17 different ACE epitopes to detect changes in ACE conformation induced by tumor growth (conformational ACE fingerprint). Results ACE immunostaining was dramatically decreased in lung cancer tissues confirmed by a 3-fold decrease in ACE activity. The conformational fingerprint of ACE from tumor lung tissues differed from normal lung (6/17 mAbs) and reflected primarily higher ACE sialylation. The increase in ZPHL/HHL ratio in lung cancer tissues was consistent with greater conformational changes of ACE. Limited analysis of the conformational ACE fingerprint in normal lung tissue and lung cancer tissue form the same patient suggested a remote effect of tumor tissue on ACE conformation and/or on “field cancerization” in a morphologically-normal lung tissues. Conclusions/Significance Local conformation of ACE is significantly altered in tumor lung tissues and may be detected by conformational fingerprinting of human ACE.
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Abstract
Epithelial cells of prostate express significant level of ACE and, as a result, seminal fluid has 50-fold more ACE than plasma. The substitution of highly specialized prostate epithelial cells by tumor cells results in dramatic decrease in ACE production in prostate tissues. We performed detailed characterization of ACE status in prostate tissues from patients with benign prostate hyperplasia (BPH) and prostate cancer (PC) using new approach- ACE phenotyping, that includes evaluation of: 1) ACE activity with two substrates (HHL and ZPHL); 2) the ratio of the rates of their hydrolysis (ZPHL/HHL ratio); 3) the ratio of immunoreactive ACE protein to ACE activity; 4) the pattern of mAbs binding to different epitopes on ACE – ACE conformational fingerprint - to reveal conformational changes in prostate ACE due to prostate pathology. ACE activity dramatically decreased and the ratio of immunoreactive ACE protein to ACE activity increased in PC tissues. The catalytic parameter, ZPHL/HHL ratio, increased in prostate tissues from all patients with PC, but was did not change for most |BPH patients. Nevertheless, prostate tissues of several patients diagnosed with BPH based on histology, also demonstrated decreased ACE activity and increased immunoreactive ACE protein/ACE activity and ZPHL/HHL ratios, that could be considered as more early indicators of prostate cancer development than routine histology. Thus, ACE phenotyping of prostate biopsies has a potential to be an effective approach for early diagnostics of prostate cancer or at least for differential diagnostics of BPH and PC.
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Lubbe L, Sturrock ED. Interacting cogs in the machinery of the renin angiotensin system. Biophys Rev 2019; 11:583-589. [PMID: 31177382 PMCID: PMC6682192 DOI: 10.1007/s12551-019-00555-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Accepted: 05/29/2019] [Indexed: 01/19/2023] Open
Abstract
Somatic angiotensin converting enzyme (sACE) is well-known for its role in blood pressure regulation and consequently, ACE inhibitors are widely prescribed for the treatment of hypertension. More than 60 years after the discovery of sACE, however, the molecular details of its substrate hydrolysis and inhibition are still poorly understood. Isothermal titration calorimetry, molecular dynamics simulations and fine epitope mapping suggest that substrate or inhibitor binding triggers a hinging motion between the two subdomains of each domain. Ligand binding to one domain further induces a conformational change in sACE to negatively affect the second domain's function and can also cause dimerization between sACE molecules. This has been linked to an increase in sACE expression via intracellular signalling. Inhibitor-induced dimerization could thus decrease the efficacy of hypertension treatment. At present, the only structural information available for sACE are crystal structures of the truncated domains in the closed conformation due to the presence of ligands. These structures do not provide any information regarding the open active site conformation prior to ligand binding, the relative orientation of the two domains in full-length sACE, or the dimerization interface. To guarantee effective therapeutic intervention, further research is required to investigate the hinging, negative cooperativity and dimerization of sACE. This review describes our current understanding of these interactions and proposes how recent advances in cryo-electron microscopy could enable structural elucidation of their mechanisms.
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Affiliation(s)
- Lizelle Lubbe
- Department of Integrative Biomedical Sciences, Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Observatory, Cape Town, 7925, South Africa
| | - Edward D Sturrock
- Department of Integrative Biomedical Sciences, Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Observatory, Cape Town, 7925, South Africa.
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Danilov SM, Tikhomirova VE, Kryukova OV, Balatsky AV, Bulaeva NI, Golukhova EZ, Bokeria LA, Samokhodskaya LM, Kost OA. Conformational fingerprint of blood and tissue ACEs: Personalized approach. PLoS One 2018; 13:e0209861. [PMID: 30589901 PMCID: PMC6307727 DOI: 10.1371/journal.pone.0209861] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2018] [Accepted: 12/12/2018] [Indexed: 11/18/2022] Open
Abstract
Background The pattern of binding of monoclonal antibodies (mAbs) to 18 epitopes on human angiotensin I-converting enzyme (ACE)–“conformational fingerprint of ACE”–is a sensitive marker of subtle conformational changes of ACE due to mutations, different glycosylation in various cells, the presence of ACE inhibitors and specific effectors, etc. Methodology/Principal findings We described in detail the methodology of the conformational fingerprinting of human blood and tissue ACEs that allows detecting differences in surface topography of ACE from different tissues, as well detecting inter-individual differences. Besides, we compared the sensitivity of the detection of ACE inhibitors in the patient’s plasma using conformational fingerprinting of ACE (with only 2 mAbs to ACE, 1G12 and 9B9) and already accepted kinetic assay and demonstrated that the mAbs-based assay is an order of magnitude more sensitive. This approach is also very effective in detection of known (like bilirubin and lysozyme) and still unknown ACE effectors/inhibitors which nature and set could vary in different tissues or different patients. Conclusions/Significance Phenotyping of ACE (and conformational fingerprinting of ACE as a part of this novel approach for characterization of ACE) in individuals really became informative and clinically relevant. Appreciation (and counting on) of inter-individual differences in ACE conformation and accompanying effectors make the application of this approach for future personalized medicine with ACE inhibitors more accurate. This (or similar) methodology can be applied to any enzyme/protein for which there is a number of mAbs to its different epitopes.
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Affiliation(s)
- Sergei M. Danilov
- Department of Anesthesiology, University of Illinois at Chicago, Illinois, United States of America
- University of Arizona Health Sciences, Tucson, Arizona, United States of America
- Medical Center, Lomonosov Moscow State University, Russia
- * E-mail:
| | - Victoria E. Tikhomirova
- Chemistry Faculty, Lomonosov Moscow State University, Russia
- Bakulev Center for Cardiovascular Surgery, Moscow, Russia
| | - Olga V. Kryukova
- Chemistry Faculty, Lomonosov Moscow State University, Russia
- Bakulev Center for Cardiovascular Surgery, Moscow, Russia
| | | | | | | | - Leo A. Bokeria
- Bakulev Center for Cardiovascular Surgery, Moscow, Russia
| | | | - Olga A. Kost
- Chemistry Faculty, Lomonosov Moscow State University, Russia
- Bakulev Center for Cardiovascular Surgery, Moscow, Russia
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8
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Danilov SM, Tikhomirova VE, Metzger R, Naperova IA, Bukina TM, Goker-Alpan O, Tayebi N, Gayfullin NM, Schwartz DE, Samokhodskaya LM, Kost OA, Sidransky E. ACE phenotyping in Gaucher disease. Mol Genet Metab 2018; 123:501-510. [PMID: 29478818 PMCID: PMC5891352 DOI: 10.1016/j.ymgme.2018.02.007] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/12/2018] [Accepted: 02/13/2018] [Indexed: 11/24/2022]
Abstract
BACKGROUND Gaucher disease is characterized by the activation of splenic and hepatic macrophages, accompanied by dramatically increased levels of angiotensin-converting enzyme (ACE). To evaluate the source of the elevated blood ACE, we performed complete ACE phenotyping using blood, spleen and liver samples from patients with Gaucher disease and controls. METHODS ACE phenotyping included 1) immunohistochemical staining for ACE; 2) measuring ACE activity with two substrates (HHL and ZPHL); 3) calculating the ratio of the rates of substrate hydrolysis (ZPHL/HHL ratio); 4) assessing the conformational fingerprint of ACE by evaluating the pattern of binding of monoclonal antibodies to 16 different ACE epitopes. RESULTS We show that in patients with Gaucher disease, the dramatically increased levels of ACE originate from activated splenic and/or hepatic macrophages (Gaucher cells), and that both its conformational fingerprint and kinetic characteristics (ZPHL/HHL ratio) differ from controls and from patients with sarcoid granulomas. Furthermore, normal spleen was found to produce high levels of endogenous ACE inhibitors and a novel, tightly-bound 10-30 kDa ACE effector which is deficient in Gaucher spleen. CONCLUSIONS The conformation of ACE is tissue-specific. In Gaucher disease, ACE produced by activated splenic macrophages differs from that in hepatic macrophages, as well as from macrophages and dendritic cells in sarcoid granulomas. The observed differences are likely due to altered ACE glycosylation or sialylation in these diseased organs. The conformational differences in ACE may serve as a specific biomarker for Gaucher disease.
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Affiliation(s)
- Sergei M Danilov
- Department of Anesthesiology, University of Illinois at Chicago, IL, USA; Department of Medicine, University of Arizona, Tucson, AZ, USA.
| | | | - Roman Metzger
- Department of Pediatric and Adolescent Surgery, Paracelsus Medical University, Salzburg, Austria
| | - Irina A Naperova
- Department of Chemistry, Lomonosov Moscow State University, Russia
| | | | - Ozlem Goker-Alpan
- Section of Molecular Neurogenetics, Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
| | - Nahid Tayebi
- Section of Molecular Neurogenetics, Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
| | - Nurshat M Gayfullin
- Medical Center, Lomonosov Moscow State University, Russia; Department of Fundamental Medicine, Lomonosov Moscow State University, Russia
| | - David E Schwartz
- Department of Anesthesiology, University of Illinois at Chicago, IL, USA
| | | | - Olga A Kost
- Department of Chemistry, Lomonosov Moscow State University, Russia
| | - Ellen Sidransky
- Section of Molecular Neurogenetics, Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
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Kost OA, Tikhomirova VE, Kryukova OV, Gusakov AV, Bulaeva NI, Evdokimov VV, Golukhova EZ, Danilov SM. Conformational “Fingerprint” of the Angiotensin-Converting Enzyme. RUSSIAN JOURNAL OF BIOORGANIC CHEMISTRY 2018. [DOI: 10.1134/s1068162018010107] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Efimov GA, Raats JMH, Chirivi RGS, van Rosmalen JWG, Nedospasov SA. Humanization of Murine Monoclonal anti-hTNF Antibody: The F10 Story. Mol Biol 2017. [DOI: 10.1134/s0026893317060061] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Danilov SM. Conformational Fingerprinting Using Monoclonal Antibodies (on the Example of Angiotensin I-Converting Enzyme-ACE). Mol Biol 2017; 51:906-920. [PMID: 32287393 PMCID: PMC7102274 DOI: 10.1134/s0026893317060048] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2017] [Accepted: 06/02/2017] [Indexed: 11/22/2022]
Abstract
During the past 30 years my laboratory has generated 40+ monoclonal antibodies (mAbs) directed to structural and conformational epitopes on human ACE as well as ACE from rats, mice and other species. These mAbs were successfully used for detection and quantification of ACE by ELISA, Western blotting, flow cytometry and immunohistochemistry. In all these applications mainly single mAbs were used. We hypothesized that we can obtain a completely new kind of information about ACE structure and function if we use the whole set of mAbs directed to different epitopes on the ACE molecule. When we finished epitope mapping of all mAbs to ACE (and especially, those recognizing conformational epitopes), we realized that we had obtained a new tool to study ACE. First, we demonstrated that binding of some mAbs is very sensitive to local conformational changes on the ACE surface-due to local denaturation, inactivation, ACE inhibitor or mAbs binding or due to diseases. Second, we were able to detect, localize and characterize several human ACE mutations. And, finally, we established a new concept-conformational fingerprinting of ACE using mAbs that in turn allowed us to obtain evidence for tissue specificity of ACE, which has promising scientific and diagnostic perspectives. The initial goal for the generation of mAbs to ACE 30 years ago was obtaining mAbs to organ-specific endothelial cells, which could be used for organ-specific drug delivery. Our systematic work on characterization of mAbs to numerous epitopes on ACE during these years has lead not only to the generation of the most effective mAbs for specific drug/gene delivery into the lung capillaries, but also to the establishment of the concept of conformational fingerprinting of ACE, which in turn gives a theoretical base for the generation of mAbs, specific for ACE from different organs. We believe that this concept could be applicable for any glycoprotein against which there is a set of mAbs to different epitopes.
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Affiliation(s)
- S. M. Danilov
- University of Illinois at Chicago, Chicago, USA
- Arizona University, Tucson, USA
- Medical Scientific and Educational Center of Moscow State University, Moscow, 119991 Russia
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Abstract
Aims Angiotensin-converting enzyme (ACE), which metabolizes many peptides and plays a key role in blood pressure regulation and vascular remodeling, is expressed as a type-1 membrane glycoprotein on the surface of different cells, including endothelial cells of the heart. We hypothesized that the local conformation and, therefore, the properties of heart ACE could differ from lung ACE due to different microenvironment in these organs. Methods and results We performed ACE phenotyping (ACE levels, conformation and kinetic characteristics) in the human heart and compared it with that in the lung. ACE activity in heart tissues was 10–15 lower than that in lung. Various ACE effectors, LMW endogenous ACE inhibitors and HMW ACE-binding partners, were shown to be present in both heart and lung tissues. “Conformational fingerprint” of heart ACE (i.e., the pattern of 17 mAbs binding to different epitopes on the ACE surface) significantly differed from that of lung ACE, which reflects differences in the local conformations of these ACEs, likely controlled by different ACE glycosylation in these organs. Substrate specificity and pH-optima of the heart and lung ACEs also differed. Moreover, even within heart the apparent ACE activities, the local ACE conformations, and the content of ACE inhibitors differ in atria and ventricles. Conclusions Significant differences in the local conformations and kinetic properties of heart and lung ACEs demonstrate tissue specificity of ACE and provide a structural base for the development of mAbs able to distinguish heart and lung ACEs as a potential blood test for predicting atrial fibrillation risk.
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Danilov SM, Lünsdorf H, Akinbi HT, Nesterovitch AB, Epshtein Y, Letsiou E, Kryukova OV, Piegeler T, Golukhova EZ, Schwartz DE, Dull RO, Minshall RD, Kost OA, Garcia JGN. Lysozyme and bilirubin bind to ACE and regulate its conformation and shedding. Sci Rep 2016; 6:34913. [PMID: 27734897 PMCID: PMC5062130 DOI: 10.1038/srep34913] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2016] [Accepted: 09/21/2016] [Indexed: 11/08/2022] Open
Abstract
Angiotensin I-converting enzyme (ACE) hydrolyzes numerous peptides and is a critical participant in blood pressure regulation and vascular remodeling. Elevated tissue ACE levels are associated with increased risk for cardiovascular and respiratory disorders. Blood ACE concentrations are determined by proteolytic cleavage of ACE from the endothelial cell surface, a process that remains incompletely understood. In this study, we identified a novel ACE gene mutation (Arg532Trp substitution in the N domain of somatic ACE) that increases blood ACE activity 7-fold and interrogated the mechanism by which this mutation significantly increases blood ACE levels. We hypothesized that this ACE mutation disrupts the binding site for blood components which may stabilize ACE conformation and diminish ACE shedding. We identified the ACE-binding protein in the blood as lysozyme and also a Low Molecular Weight (LMW) ACE effector, bilirubin, which act in concert to regulate ACE conformation and thereby influence ACE shedding. These results provide mechanistic insight into the elevated blood level of ACE observed in patients on ACE inhibitor therapy and elevated blood lysozyme and ACE levels in sarcoidosis patients.
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Affiliation(s)
- Sergei M. Danilov
- Department of Anesthesiology, University of Illinois at Chicago, Chicago, IL, USA
- Institute for Personalized Respiratory Medicine, University of Illinois at Chicago, Chicago, IL, USA
| | - Heinrich Lünsdorf
- Central Facility of Microscopy, Helmholtz-Center of Infection Research, Braunschweig, Germany
| | - Henry T. Akinbi
- Divisions of Pulmonary Biology and Neonatology, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH, USA
| | | | - Yuliya Epshtein
- Institute for Personalized Respiratory Medicine, University of Illinois at Chicago, Chicago, IL, USA
| | - Eleftheria Letsiou
- Institute for Personalized Respiratory Medicine, University of Illinois at Chicago, Chicago, IL, USA
| | - Olga V. Kryukova
- Faculty of Chemistry, Lomonosov Moscow State University, Moscow, Russia
| | - Tobias Piegeler
- Department of Anesthesiology, University of Illinois at Chicago, Chicago, IL, USA
- Institute of Anesthesiology, University Hospital Zurich, Zurich, Switzerland
| | | | - David E. Schwartz
- Department of Anesthesiology, University of Illinois at Chicago, Chicago, IL, USA
| | - Randal O. Dull
- Department of Anesthesiology, University of Illinois at Chicago, Chicago, IL, USA
| | - Richard D. Minshall
- Department of Anesthesiology, University of Illinois at Chicago, Chicago, IL, USA
- Department of Pharmacology, University of Illinois at Chicago, Chicago, IL, USA
| | - Olga A. Kost
- Faculty of Chemistry, Lomonosov Moscow State University, Moscow, Russia
| | - Joe G. N. Garcia
- Institute for Personalized Respiratory Medicine, University of Illinois at Chicago, Chicago, IL, USA
- University of Arizona Health Sciences, Tucson, AZ, USA
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14
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Kryukova OV, Tikhomirova VE, Golukhova EZ, Evdokimov VV, Kalantarov GF, Trakht IN, Schwartz DE, Dull RO, Gusakov AV, Uporov IV, Kost OA, Danilov SM. Tissue Specificity of Human Angiotensin I-Converting Enzyme. PLoS One 2015; 10:e0143455. [PMID: 26600189 PMCID: PMC4658169 DOI: 10.1371/journal.pone.0143455] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2015] [Accepted: 11/04/2015] [Indexed: 12/18/2022] Open
Abstract
Background Angiotensin-converting enzyme (ACE), which metabolizes many peptides and plays a key role in blood pressure regulation and vascular remodeling, as well as in reproductive functions, is expressed as a type-1 membrane glycoprotein on the surface of endothelial and epithelial cells. ACE also presents as a soluble form in biological fluids, among which seminal fluid being the richest in ACE content - 50-fold more than that in blood. Methods/Principal Findings We performed conformational fingerprinting of lung and seminal fluid ACEs using a set of monoclonal antibodies (mAbs) to 17 epitopes of human ACE and determined the effects of potential ACE-binding partners on mAbs binding to these two different ACEs. Patterns of mAbs binding to ACEs from lung and from seminal fluid dramatically differed, which reflects difference in the local conformations of these ACEs, likely due to different patterns of ACE glycosylation in the lung endothelial cells and epithelial cells of epididymis/prostate (source of seminal fluid ACE), confirmed by mass-spectrometry of ACEs tryptic digests. Conclusions Dramatic differences in the local conformations of seminal fluid and lung ACEs, as well as the effects of ACE-binding partners on mAbs binding to these ACEs, suggest different regulation of ACE functions and shedding from epithelial cells in epididymis and prostate and endothelial cells of lung capillaries. The differences in local conformation of ACE could be the base for the generation of mAbs distingushing tissue-specific ACEs.
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Affiliation(s)
- Olga V. Kryukova
- Chemical Faculty, M.V.Lomonosov Moscow State University, Moscow, Russia
| | | | | | | | | | - Ilya N. Trakht
- Department of Medicine, Columbia University, New York, NY, United States of America
| | - David E. Schwartz
- Department of Anesthesiology, University of Illinois at Chicago, Chicago, IL, United States of America
| | - Randal O. Dull
- Department of Anesthesiology, University of Illinois at Chicago, Chicago, IL, United States of America
| | | | - Igor V. Uporov
- Chemical Faculty, M.V.Lomonosov Moscow State University, Moscow, Russia
| | - Olga A. Kost
- Chemical Faculty, M.V.Lomonosov Moscow State University, Moscow, Russia
- * E-mail: (SMD); (OAK)
| | - Sergei M. Danilov
- Department of Anesthesiology, University of Illinois at Chicago, Chicago, IL, United States of America
- * E-mail: (SMD); (OAK)
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15
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Danilov SM, Wade MS, Schwager SL, Douglas RG, Nesterovitch AB, Popova IA, Hogarth KD, Bhardwaj N, Schwartz DE, Sturrock ED, Garcia JGN. A novel angiotensin I-converting enzyme mutation (S333W) impairs N-domain enzymatic cleavage of the anti-fibrotic peptide, AcSDKP. PLoS One 2014; 9:e88001. [PMID: 24505347 PMCID: PMC3913711 DOI: 10.1371/journal.pone.0088001] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2013] [Accepted: 01/03/2014] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Angiotensin I-converting enzyme (ACE) has two functional N- and C-domain active centers that display differences in the metabolism of biologically-active peptides including the hemoregulatory tetrapeptide, Ac-SDKP, hydrolysed preferentially by the N domain active center. Elevated Ac-SDKP concentrations are associated with reduced tissue fibrosis. RESULTS We identified a patient of African descent exhibiting unusual blood ACE kinetics with reduced relative hydrolysis of two synthetic ACE substrates (ZPHL/HHL ratio) suggestive of the ACE N domain center inactivation. Inhibition of blood ACE activity by anti-catalytic mAbs and ACE inhibitors and conformational fingerprint of blood ACE suggested overall conformational changes in the ACE molecule and sequencing identified Ser333Trp substitution in the N domain of ACE. In silico analysis demonstrated S333W localized in the S1 pocket of the active site of the N domain with the bulky Trp adversely affecting binding of ACE substrates due to steric hindrance. Expression of mutant ACE (S333W) in CHO cells confirmed altered kinetic properties of mutant ACE and conformational changes in the N domain. Further, the S333W mutant displayed decreased ability (5-fold) to cleave the physiological substrate AcSDKP compared to wild-type ACE. CONCLUSIONS AND SIGNIFICANCE A novel Ser333Trp ACE mutation results in dramatic changes in ACE kinetic properties and lowered clearance of Ac-SDKP. Individuals with this mutation (likely with significantly increased levels of the hemoregulatory tetrapeptide in blood and tissues), may confer protection against fibrosis.
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Affiliation(s)
- Sergei M. Danilov
- Institute for Personalized Respiratory Medicine, University of Illinois at Chicago, Chicago, Illinois, United States of America
- Department of Anesthesiology, University of Illinois at Chicago, Chicago, Illinois, United States of America
- * E-mail:
| | - Michael S. Wade
- Institute for Personalized Respiratory Medicine, University of Illinois at Chicago, Chicago, Illinois, United States of America
| | - Sylva L. Schwager
- Institute of Infectious Disease and Molecular Medicine and Division of Medical Biochemistry, University of Cape Town, Cape Town, South Africa
| | - Ross G. Douglas
- Institute of Infectious Disease and Molecular Medicine and Division of Medical Biochemistry, University of Cape Town, Cape Town, South Africa
| | | | - Isolda A. Popova
- Chemistry of Life Processes Institute, Northwestern University, Evanston, Illinois, United States of America
| | - Kyle D. Hogarth
- Department of Medicine, University of Chicago, Chicago, Illinois, United States of America
| | - Nakul Bhardwaj
- Department of Medicine, University of Chicago, Chicago, Illinois, United States of America
| | - David E. Schwartz
- Department of Anesthesiology, University of Illinois at Chicago, Chicago, Illinois, United States of America
| | - Edward D. Sturrock
- Institute of Infectious Disease and Molecular Medicine and Division of Medical Biochemistry, University of Cape Town, Cape Town, South Africa
| | - Joe G. N. Garcia
- Department of Medicine, University of Arizona, Tucson, Arizona, United States of America
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16
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Bernstein KE, Ong FS, Blackwell WLB, Shah KH, Giani JF, Gonzalez-Villalobos RA, Shen XZ, Fuchs S, Touyz RM. A modern understanding of the traditional and nontraditional biological functions of angiotensin-converting enzyme. Pharmacol Rev 2012; 65:1-46. [PMID: 23257181 DOI: 10.1124/pr.112.006809] [Citation(s) in RCA: 201] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Angiotensin-converting enzyme (ACE) is a zinc-dependent peptidase responsible for converting angiotensin I into the vasoconstrictor angiotensin II. However, ACE is a relatively nonspecific peptidase that is capable of cleaving a wide range of substrates. Because of this, ACE and its peptide substrates and products affect many physiologic processes, including blood pressure control, hematopoiesis, reproduction, renal development, renal function, and the immune response. The defining feature of ACE is that it is composed of two homologous and independently catalytic domains, the result of an ancient gene duplication, and ACE-like genes are widely distributed in nature. The two ACE catalytic domains contribute to the wide substrate diversity of ACE and, by extension, the physiologic impact of the enzyme. Several studies suggest that the two catalytic domains have different biologic functions. Recently, the X-ray crystal structure of ACE has elucidated some of the structural differences between the two ACE domains. This is important now that ACE domain-specific inhibitors have been synthesized and characterized. Once widely available, these reagents will undoubtedly be powerful tools for probing the physiologic actions of each ACE domain. In turn, this knowledge should allow clinicians to envision new therapies for diseases not currently treated with ACE inhibitors.
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Affiliation(s)
- Kenneth E Bernstein
- Cedars-Sinai Medical Center, 8700 Beverly Boulevard, Davis 2021, Los Angeles, CA 90048, USA.
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17
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Petrov MN, Shilo VY, Tarasov AV, Schwartz DE, Garcia JGN, Kost OA, Danilov SM. Conformational changes of blood ACE in chronic uremia. PLoS One 2012; 7:e49290. [PMID: 23166630 PMCID: PMC3500299 DOI: 10.1371/journal.pone.0049290] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2012] [Accepted: 10/08/2012] [Indexed: 11/30/2022] Open
Abstract
Background The pattern of binding of monoclonal antibodies (mAbs) to 16 epitopes on human angiotensin I-converting enzyme (ACE) comprise a conformational ACE fingerprint and is a sensitive marker of subtle protein conformational changes. Hypothesis Toxic substances in the blood of patients with uremia due to End Stage Renal Disease (ESRD) can induce local conformational changes in the ACE protein globule and alter the efficacy of ACE inhibitors. Methodology/Principal Findings The recognition of ACE by 16 mAbs to the epitopes on the N and C domains of ACE was estimated using an immune-capture enzymatic plate precipitation assay. The precipitation pattern of blood ACE by a set of mAbs was substantially influenced by the presence of ACE inhibitors with the most dramatic local conformational change noted in the N-domain region recognized by mAb 1G12. The “short” ACE inhibitor enalaprilat (tripeptide analog) and “long” inhibitor teprotide (nonapeptide) produced strikingly different mAb 1G12 binding with enalaprilat strongly increasing mAb 1G12 binding and teprotide decreasing binding. Reduction in S-S bonds via glutathione and dithiothreitol treatment increased 1G12 binding to blood ACE in a manner comparable to enalaprilat. Some patients with uremia due to ESRD exhibited significantly increased mAb 1G12 binding to blood ACE and increased ACE activity towards angiotensin I accompanied by reduced ACE inhibition by inhibitory mAbs and ACE inhibitors. Conclusions/Significance The estimation of relative mAb 1G12 binding to blood ACE detects a subpopulation of ESRD patients with conformationally changed ACE, which activity is less suppressible by ACE inhibitors. This parameter may potentially serve as a biomarker for those patients who may need higher concentrations of ACE inhibitors upon anti-hypertensive therapy.
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Affiliation(s)
- Maxim N. Petrov
- Department of Chemistry, Lomonosov Moscow State University, Moscow, Russia
| | - Valery Y. Shilo
- Department of Nephrology, Moscow University for Medicine and Dentistry, Moscow, Russia
| | | | - David E. Schwartz
- Department of Anesthesiology, University of Illinois at Chicago, Chicago, Illinois, United States of America
| | - Joe G. N. Garcia
- Institute for Personalized Respiratory Medicine, University of Illinois at Chicago, Chicago, Illinois, United States of America
| | - Olga A. Kost
- Department of Chemistry, Lomonosov Moscow State University, Moscow, Russia
| | - Sergei M. Danilov
- Department of Anesthesiology, University of Illinois at Chicago, Chicago, Illinois, United States of America
- Institute for Personalized Respiratory Medicine, University of Illinois at Chicago, Chicago, Illinois, United States of America
- National Cardiology Research Center, Moscow, Russia
- * E-mail:
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18
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Chacko AM, Nayak M, Greineder CF, DeLisser HM, Muzykantov VR. Collaborative enhancement of antibody binding to distinct PECAM-1 epitopes modulates endothelial targeting. PLoS One 2012; 7:e34958. [PMID: 22514693 PMCID: PMC3325922 DOI: 10.1371/journal.pone.0034958] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2011] [Accepted: 03/08/2012] [Indexed: 12/21/2022] Open
Abstract
Antibodies to platelet endothelial cell adhesion molecule-1 (PECAM-1) facilitate targeted drug delivery to endothelial cells by “vascular immunotargeting.” To define the targeting quantitatively, we investigated the endothelial binding of monoclonal antibodies (mAbs) to extracellular epitopes of PECAM-1. Surprisingly, we have found in human and mouse cell culture models that the endothelial binding of PECAM-directed mAbs and scFv therapeutic fusion protein is increased by co-administration of a paired mAb directed to an adjacent, yet distinct PECAM-1 epitope. This results in significant enhancement of functional activity of a PECAM-1-targeted scFv-thrombomodulin fusion protein generating therapeutic activated Protein C. The “collaborative enhancement” of mAb binding is affirmed in vivo, as manifested by enhanced pulmonary accumulation of intravenously administered radiolabeled PECAM-1 mAb when co-injected with an unlabeled paired mAb in mice. This is the first demonstration of a positive modulatory effect of endothelial binding and vascular immunotargeting provided by the simultaneous binding a paired mAb to adjacent distinct epitopes. The “collaborative enhancement” phenomenon provides a novel paradigm for optimizing the endothelial-targeted delivery of therapeutic agents.
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Affiliation(s)
- Ann-Marie Chacko
- Department of Radiology, Division of Nuclear Medicine and Clinical Molecular Imaging, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
- Institute for Translational Medicine and Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Madhura Nayak
- Department of Radiology, Division of Nuclear Medicine and Clinical Molecular Imaging, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Colin F. Greineder
- Department of Emergency Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
- Institute for Translational Medicine and Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Horace M. DeLisser
- Pulmonary, Allergy & Critical Care Division, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Vladimir R. Muzykantov
- Institute for Translational Medicine and Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
- * E-mail:
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19
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An angiotensin I-converting enzyme mutation (Y465D) causes a dramatic increase in blood ACE via accelerated ACE shedding. PLoS One 2011; 6:e25952. [PMID: 21998728 PMCID: PMC3187827 DOI: 10.1371/journal.pone.0025952] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2011] [Accepted: 09/14/2011] [Indexed: 11/23/2022] Open
Abstract
Background Angiotensin I-converting enzyme (ACE) metabolizes a range of peptidic substrates and plays a key role in blood pressure regulation and vascular remodeling. Thus, elevated ACE levels may be associated with an increased risk for different cardiovascular or respiratory diseases. Previously, a striking familial elevation in blood ACE was explained by mutations in the ACE juxtamembrane region that enhanced the cleavage-secretion process. Recently, we found a family whose affected members had a 6-fold increase in blood ACE and a Tyr465Asp (Y465D) substitution, distal to the stalk region, in the N domain of ACE. Methodology/Principal Findings HEK and CHO cells expressing mutant (Tyr465Asp) ACE demonstrate a 3- and 8-fold increase, respectively, in the rate of ACE shedding compared to wild-type ACE. Conformational fingerprinting of mutant ACE demonstrated dramatic changes in ACE conformation in several different epitopes of ACE. Cell ELISA carried out on CHO-ACE cells also demonstrated significant changes in local ACE conformation, particularly proximal to the stalk region. However, the cleavage site of the mutant ACE - between Arg1203 and Ser1204 - was the same as that of WT ACE. The Y465D substitution is localized in the interface of the N-domain dimer (from the crystal structure) and abolishes a hydrogen bond between Tyr465 in one monomer and Asp462 in another. Conclusions/Significance The Y465D substitution results in dramatic increase in the rate of ACE shedding and is associated with significant local conformational changes in ACE. These changes could result in increased ACE dimerization and accessibility of the stalk region or the entire sACE, thus increasing the rate of cleavage by the putative ACE secretase (sheddase).
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20
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Danilov SM, Balyasnikova IV, Danilova AS, Naperova IA, Arablinskaya NE, Borisov SE, Metzger R, Franke FE, Schwartz DE, Gachok IV, Trakht IN, Kost OA, Garcia JGN. Conformational fingerprinting of the angiotensin I-converting enzyme (ACE). 1. Application in sarcoidosis. J Proteome Res 2010; 9:5782-93. [PMID: 20873814 DOI: 10.1021/pr100564r] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Fine epitope mapping of monoclonal antibodies (mAbs) to 16 epitopes on human angiotensin I-converting enzyme (ACE) revealed that the epitopes of all mAbs contained putative glycosylation sites. ACE glycosylation is both cell- and tissue-specific and, therefore, the local conformation of ACE produced by different cells could be also unique. The pattern of ACE binding by a set of mAbs to 16 epitopes of human ACE - "conformational fingerprint of ACE" - is the most sensitive marker of ACE conformation and could be cell- and tissue-specific. The recognition of ACEs by mAbs to ACE was estimated using an immune-capture enzymatic plate precipitation assay. Precipitation patterns of soluble recombinant ACE released from Chinese hamster ovary (CHO)-ACE cells was influenced by conditions that alter ACE glycosylation. This pattern was also strongly cell type specific. Patients with sarcoidosis exhibited conformational fingerprints of tissue ACE (lungs and lymph nodes), as well as blood ACE, which were distinct from controls. Conformational fingerprinting of ACE may detect ACE originated from the cells other than endothelial cells in the blood and when combined with elevated blood ACE levels in patients with sarcoidosis may potentially reflect extrapulmonary sarcoidosis involvement (bone marrow, spleen, liver). If proven true, this would serve as a biomarker of enormous potential clinical significance.
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Affiliation(s)
- Sergei M Danilov
- Department of Anesthesiology, University of Illinois, Chicago, IL, USA.
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21
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Angiotensin I-converting enzyme Gln1069Arg mutation impairs trafficking to the cell surface resulting in selective denaturation of the C-domain. PLoS One 2010; 5:e10438. [PMID: 20454656 PMCID: PMC2862704 DOI: 10.1371/journal.pone.0010438] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2010] [Accepted: 03/20/2010] [Indexed: 11/29/2022] Open
Abstract
Background Angiotensin-converting enzyme (ACE; Kininase II; CD143) hydrolyzes small peptides such as angiotensin I, bradykinin, substance P, LH-RH and several others and thus plays a key role in blood pressure regulation and vascular remodeling. Complete absence of ACE in humans leads to renal tubular dysgenesis (RTD), a severe disorder of renal tubule development characterized by persistent fetal anuria and perinatal death. Methodology/Principal Findings Patient with RTD in Lisbon, Portugal, maintained by peritoneal dialysis since birth, was found to have a homozygous substitution of Arg for Glu at position 1069 in the C-terminal domain of ACE (Q1069R) resulting in absence of plasma ACE activity; both parents and a brother who are heterozygous carriers of this mutation had exactly half-normal plasma ACE activity compared to healthy individuals. We hypothesized that the Q1069R substitution impaired ACE trafficking to the cell surface and led to accumulation of catalytically inactive ACE in the cell cytoplasm. CHO cells expressing wild-type (WT) vs. Q1069R-ACE demonstrated the mutant accumulates intracellularly and also that it is significantly degraded by intracellular proteases. Q1069R-ACE retained catalytic and immunological characteristics of WT-ACE N domain whereas it had 10–20% of the nativity of the WT-ACE C domain. A combination of chemical (sodium butyrate) or pharmacological (ACE inhibitor) chaperones with proteasome inhibitors (MG 132 or bortezomib) significantly restored trafficking of Q1069R-ACE to the cell surface and increased ACE activity in the cell culture media 4-fold. Conclusions/Significance Homozygous Q1069R substitution results in an ACE trafficking and processing defect which can be rescued, at least in cell culture, by a combination of chaperones and proteasome inhibitors. Further studies are required to determine whether similar treatment of individuals with this ACE mutation would provide therapeutic benefits such as concentration of primary urine.
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22
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Chen HL, Lünsdorf H, Hecht HJ, Tsai H. Porcine pulmonary angiotensin I-converting enzyme--biochemical characterization and spatial arrangement of the N- and C-domains by three-dimensional electron microscopic reconstruction. Micron 2010; 41:674-85. [PMID: 20427191 DOI: 10.1016/j.micron.2010.01.005] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The somatic angiotensin I-converting enzyme (sACE; peptidyl-dipeptidase A; EC 3.4.15.1) was isolated from pig lung and purified to homogeneity. The purified enzyme has a molecular mass of about 180 kDa. Upon proteolytic cleavage, two approximately 90 kDa fragments were obtained and identified by amino-terminal sequence analysis as the N- and C-domains of sACE. Both purified domains were shown to be catalytically active. A 2.3 nm resolution model of sACE was obtained by three-dimensional electron microscopic reconstruction of negatively stained sACE particles, based on atomic X-ray data fitting. Our model shows for the first time the relative orientation of the sACE catalytically active domains and their spatial distance.
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Affiliation(s)
- Hui-Ling Chen
- Development Center for Biotechnology, Taipei County 221, Taiwan, ROC
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23
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Gordon K, Balyasnikova IV, Nesterovitch AB, Schwartz DE, Sturrock ED, Danilov SM. Fine epitope mapping of monoclonal antibodies 9B9 and 3G8 to the N domain of angiotensin-converting enzyme (CD143) defines a region involved in regulating angiotensin-converting enzyme dimerization and shedding. ACTA ACUST UNITED AC 2009; 75:136-50. [PMID: 20003136 DOI: 10.1111/j.1399-0039.2009.01416.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
A panel of monoclonal antibodies (mAbs) raised against both the N and C domains of angiotensin-I-converting enzyme (ACE, peptidyl dipeptidase, EC 3.4.15.2) have been extensively mapped and have facilitated the study of various aspects of ACE structure and biology. In this study, we characterize two mAbs, 9B9 and 3G8, that recognize the N domain of ACE and that influence shedding and dimerization. Fine epitope mapping was performed, which mapped the epitopes for these mAbs to the N terminal region of the N domain where they overlap to a large extent, despite having different effects on ACE processing. The mAb 3G8 epitope appears to be shielded by the C domain and to be carbohydrate dependent as binding increased significantly as a result of underglycosylation, whereas these factors did not influence mAb 9B9 recognition. Three mutations within the overlapping region of these two epitopes, Q18H, L19E, and Q22A, which decreased mAb 3G8 binding to the soluble N domain, were introduced into full-length somatic ACE (sACE) to determine their influence on ACE expression and processing. Increased ACE expression, cell surface expression, and basal shedding were observed with all three mutations. Furthermore, cross-linking and western blotting of Chinese hamster ovary (CHO) cell lysates detected two distinct ACE dimers, a native and cross-linked dimer. Increasing amounts of the cross-linked dimer were observed for the mutant sACEQ22A, further implicating the overlapping region of the mAb 9B9 and 3G8 epitopes in ACE processing.
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Affiliation(s)
- K Gordon
- Division of Medical Biochemistry, Institute of Infectious Diseases and Molecular Medicine, University of Cape Town, Cape Town, South Africa
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