Lysozyme and bilirubin bind to ACE and regulate its conformation and shedding

Danilov, Sergei M.; Lünsdorf, Heinrich; Akinbi, Henry T.; Nesterovitch, Andrew B.; Epshtein, Yulia; Letsiou, Eleftheria; Kryukova, Olga; Piegeler, Tobias; Golukhova, Elena Z.; Schwartz, David E.; Dull, Randal O.; Minshall, Richard D.; Кост, О. А.; Garcia, Joe G.N.

doi:10.1038/srep34913

Cited by 29 publications

(41 citation statements)

References 63 publications

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“…While the clinical relevance of such inter-individual differences awaits further investigation, however, it could lead to the different behavior of the enzyme in some physiological processes, e.g. those including ACE interplay with effectors [7, 8] in blood and tissues.…”

Section: Resultsmentioning

confidence: 99%

“…Here, we described in detail a methodology of “conformational fingerprinting” of ACE using a panel of monoclonal antibodies to this enzyme. This approach allows one to detect the presence of ACE inhibitors in the patient’s blood and provides valuable information on the presence of low-molecular weight (LMW) effectors and ACE-binding proteins in the plasma [8] and this study and tissues (this study). Moreover, we demonstrated that conformational fingerprinting of ACE is a sensitive potential tool for detection of even inter-individual differences in ACE conformation.…”

Section: Introductionmentioning

confidence: 99%

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Conformational fingerprint of blood and tissue ACEs: Personalized approach

et al. 2018

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BackgroundThe 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 findingsWe 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/SignificancePhenotyping 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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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Conformational fingerprint of blood and tissue ACEs: Personalized approach

et al. 2018

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“…Mammalian tissues and blood contain endogenous ACE inhibitors [ 17 , 24 , 25 ] and ACE effectors [ 17 , 26 ], including putative ACE binding proteins [ 26 – 28 ]. In order to demonstrate the presence of endogenous ACE inhibitors in human tissues we compared an apparent ACE activity in the heart and lung homogenates at serial dilutions ( Fig 2 ).…”

Section: Resultsmentioning

confidence: 99%

“…When we performed purification of heart and lung ACEs by a combination of anion-exchange and affinity chromatography, we noticed significant influence of this purification procedure on the ACE conformational fingerprint ( Fig 4A and 4B , S3A Fig , and “ S2 Text ”), that is a microenvironment significantly influenced on ACE conformation in the tested tissues. Purification of both ACEs from the corresponding homogenates led to a decrease of the binding of mAbs 1G12, 6A12, and i2H5 having overlapping epitopes on the N domain [ 35 ], which could be attributed to the dissociation of endogenous ACE inhibitors [ 26 , 35 ] from the complex with ACE.…”

Section: Resultsmentioning

confidence: 99%

“… ACE activity was measured in the undiluted homogenates of human heart chambers and at 1/10 dilution as in Fig 1 . ACE protein level was quantified after precipitation of ACE by a set of mAbs and washing out putative endogenous ACE inhibitors/effectors [ 26 ]. Data are expressed as a percentage from the corresponding data for left ventricle homogenate.…”

Section: Resultsmentioning

confidence: 99%

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ACE phenotyping in human heart

et al. 2017

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AimsAngiotensin-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 resultsWe 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.ConclusionsSignificant 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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Epitope mapping of novel monoclonal antibodies to human angiotensin I‐converting enzyme

et al. 2021

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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 Isolda A. Popova and Lizelle Lubbe contributed equally.

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Lysozyme and bilirubin bind to ACE and regulate its conformation and shedding

Cited by 29 publications

References 63 publications

Conformational fingerprint of blood and tissue ACEs: Personalized approach

Conformational fingerprint of blood and tissue ACEs: Personalized approach

ACE phenotyping in human heart

Epitope mapping of novel monoclonal antibodies to human angiotensin I‐converting enzyme

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