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Pfeffer T, Krug SM, Kracke T, Schürfeld R, Colbatzky F, Kirschner P, Medert R, Freichel M, Schumacher D, Bartosova M, Zarogiannis SG, Muckenthaler MU, Altamura S, Pezer S, Volk N, Schwab C, Duensing S, Fleming T, Heidenreich E, Zschocke J, Hell R, Poschet G, Schmitt CP, Peters V. Knock-out of dipeptidase CN2 in human proximal tubular cells disrupts dipeptide and amino acid homeostasis and para- and transcellular solute transport. Acta Physiol (Oxf) 2024; 240:e14126. [PMID: 38517248 DOI: 10.1111/apha.14126] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2023] [Revised: 02/15/2024] [Accepted: 02/21/2024] [Indexed: 03/23/2024]
Abstract
AIM Although of potential biomedical relevance, dipeptide metabolism has hardly been studied. We found the dipeptidase carnosinase-2 (CN2) to be abundant in human proximal tubules, which regulate water and solute homeostasis. We therefore hypothesized, that CN2 has a key metabolic role, impacting proximal tubular transport function. METHODS A knockout of the CN2 gene (CNDP2-KO) was generated in human proximal tubule cells and characterized by metabolomics, RNA-seq analysis, paracellular permeability analysis and ion transport. RESULTS CNDP2-KO in human proximal tubule cells resulted in the accumulation of cellular dipeptides, reduction of amino acids and imbalance of related metabolic pathways, and of energy supply. RNA-seq analyses indicated altered protein metabolism and ion transport. Detailed functional studies demonstrated lower CNDP2-KO cell viability and proliferation, and altered ion and macromolecule transport via trans- and paracellular pathways. Regulatory and transport protein abundance was disturbed, either as a consequence of the metabolic imbalance or the resulting functional disequilibrium. CONCLUSION CN2 function has a major impact on intracellular amino acid and dipeptide metabolism and is essential for key metabolic and regulatory functions of proximal tubular cells. These findings deserve in vivo analysis of the relevance of CN2 for nephron function and regulation of body homeostasis.
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Affiliation(s)
- Tilman Pfeffer
- Medical Faculty Heidelberg, Center for Pediatric and Adolescent Medicine, Department I, Division of Pediatric Neurology and Metabolic Medicine, Heidelberg University, Heidelberg, Germany
- Tissue Bank of the German Center for Infection Research (DZIF), Partner Site Heidelberg, Institute of Pathology, Heidelberg University Hospital, Heidelberg, Germany
| | - Susanne M Krug
- Clinical Physiology/Nutritional Medicine, Charité-Universitätsmedizin Berlin, CBF, Berlin, Germany
| | - Tamara Kracke
- Medical Faculty Heidelberg, Center for Pediatric and Adolescent Medicine, Department I, Division of Pediatric Neurology and Metabolic Medicine, Heidelberg University, Heidelberg, Germany
| | - Robin Schürfeld
- Medical Faculty Heidelberg, Center for Pediatric and Adolescent Medicine, Department I, Division of Pediatric Neurology and Metabolic Medicine, Heidelberg University, Heidelberg, Germany
| | - Florian Colbatzky
- Medical Faculty Heidelberg, Center for Pediatric and Adolescent Medicine, Department I, Division of Pediatric Neurology and Metabolic Medicine, Heidelberg University, Heidelberg, Germany
| | - Philip Kirschner
- Medical Faculty Heidelberg, Center for Pediatric and Adolescent Medicine, Department I, Division of Pediatric Neurology and Metabolic Medicine, Heidelberg University, Heidelberg, Germany
| | - Rebekka Medert
- Institute of Pharmacology, Heidelberg University, Heidelberg, Germany
| | - Marc Freichel
- Institute of Pharmacology, Heidelberg University, Heidelberg, Germany
| | - Dagmar Schumacher
- Institute of Pharmacology, Heidelberg University, Heidelberg, Germany
| | - Maria Bartosova
- Medical Faculty Heidelberg, Center for Pediatric and Adolescent Medicine, Department I, Division of Pediatric Neurology and Metabolic Medicine, Heidelberg University, Heidelberg, Germany
| | - Sotiris G Zarogiannis
- Medical Faculty Heidelberg, Center for Pediatric and Adolescent Medicine, Department I, Division of Pediatric Neurology and Metabolic Medicine, Heidelberg University, Heidelberg, Germany
| | - Martina U Muckenthaler
- Department of Pediatric Oncology, Hematology and Immunology and Hopp Children Cancer Center (KiTZ), University Hospital Heidelberg, Heidelberg, Germany
- Molecular Medicine Partnership Unit (MMPU), EMBL and University of Heidelberg, Heidelberg, Germany
- Translational Lung Research Center Heidelberg (TLRC), German Center for Lung Research (DZL), University of Heidelberg, Heidelberg, Germany
- DZHK (German Centre for Cardiovascular Research), Partner Site Heidelberg/Mannheim, Heidelberg, Germany
| | - Sandro Altamura
- Department of Pediatric Oncology, Hematology and Immunology and Hopp Children Cancer Center (KiTZ), University Hospital Heidelberg, Heidelberg, Germany
- Molecular Medicine Partnership Unit (MMPU), EMBL and University of Heidelberg, Heidelberg, Germany
| | - Silvia Pezer
- Medical Faculty Heidelberg, Center for Pediatric and Adolescent Medicine, Department I, Division of Pediatric Neurology and Metabolic Medicine, Heidelberg University, Heidelberg, Germany
| | - Nadine Volk
- Tissue Bank of the National Center for Tumor Diseases (NCT), Heidelberg, Germany
| | - Constantin Schwab
- Institute of Pathology, University Hospital Heidelberg, Heidelberg, Germany
| | - Stefan Duensing
- Department of Urology, University Hospital Heidelberg and National Center for Tumor Diseases (NCT) Heidelberg, Heidelberg, Germany
| | - Thomas Fleming
- Internal Medicine I and Clinical Chemistry, University Hospital Heidelberg, Heidelberg, Germany
| | - Elena Heidenreich
- Centre for Organismal Studies (COS), University of Heidelberg, Heidelberg, Germany
| | - Johannes Zschocke
- Institute of Human Genetics, Medical University of Innsbruck, Innsbruck, Austria
| | - Rüdiger Hell
- Centre for Organismal Studies (COS), University of Heidelberg, Heidelberg, Germany
| | - Gernot Poschet
- Centre for Organismal Studies (COS), University of Heidelberg, Heidelberg, Germany
| | - Claus P Schmitt
- Medical Faculty Heidelberg, Center for Pediatric and Adolescent Medicine, Department I, Division of Pediatric Neurology and Metabolic Medicine, Heidelberg University, Heidelberg, Germany
| | - Verena Peters
- Medical Faculty Heidelberg, Center for Pediatric and Adolescent Medicine, Department I, Division of Pediatric Neurology and Metabolic Medicine, Heidelberg University, Heidelberg, Germany
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Schürfeld R, Pamporaki C, Peitzsch M, Rayes N, Sabri O, Rohm S, Biemann R, Sandner B, Tönjes A, Eisenhofer G. False-positive results for pheochromocytoma associated with norepinephrine reuptake blockade. Endocr Relat Cancer 2024; 31:e230063. [PMID: 37955319 PMCID: PMC10762534 DOI: 10.1530/erc-23-0063] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Accepted: 11/13/2023] [Indexed: 11/14/2023]
Abstract
Measurements of plasma metanephrines and methoxytyramine provide a sensitive test for diagnosis of pheochromocytoma/paraganglioma. False-positive results remain a problem, particularly in patients taking norepinephrine reuptake-blocking drugs. Therefore, in this retrospective observational study, we measured plasma metanephrines and methoxytyramine in 61 patients taking norepinephrine reuptake blockers (tricyclic antidepressants or serotonin-norepinephrine reuptake inhibitors) and 17 others taking selective serotonin reuptake inhibitors, all without pheochromocytoma/paraganglioma. We highlight a singular case with strongly elevated plasma normetanephrine and methoxytyramine concentrations associated with norepinephrine reuptake blockade. Data were compared to results from 252 and 1804 respective patients with and without tumors. Plasma normetanephrine was 40% higher (P < 0.0001) in patients on norepinephrine reuptake blockers and methoxytyramine was 127% higher (P = 0.0062) in patients taking tricyclic antidepressants compared to patients not taking uptake blockers and without tumors. The corresponding false-positive rates rose (P < 0.0001) from 4.8% to 23.0% for normetanephrine and from 0.9% to 28.6% for methoxytyramine. Selective serotonin reuptake inhibitors did not increase plasma concentrations of metabolites. In the highlighted case, plasma normetanephrine and methoxytyramine were elevated more than six times above upper reference limits. A pheochromocytoma/paraganglioma, however, was excluded by functional imaging. All biochemical test results normalized after discontinuation of norepinephrine reuptake blockers. These findings clarify that norepinephrine reuptake blockers usually result in mild elevations of normetanephrine and methoxytyramine that, nevertheless, significantly increase the number of false-positive results. There can, however, be exceptions where increases in normetanephrine and methoxytyramine reach pathological levels. Such exceptions may reflect failure of centrally mediated sympathoinhibition that normally occurs with the norepinephrine reuptake blockade.
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Affiliation(s)
- Robin Schürfeld
- Division of Endocrinology and Diabetes, Department of Internal Medicine, University of Leipzig, Leipzig, Germany
| | - Christina Pamporaki
- TU Dresden, Medical Clinic III, University Hospital Carl Gustav Carus, Dresden, Germany
| | - Mirko Peitzsch
- TU Dresden, Institute of Clinical Chemistry and Laboratory Medicine, Dresden, Germany
| | - Nada Rayes
- Center of Surgery, Division of Endocrine Surgery, Department for Visceral, Transplant, Thoracic, and Vascular Surgery, University of Leipzig, Leipzig, Germany
| | - Osama Sabri
- Department of Nuclear Medicine, University of Leipzig, Leipzig, Germany
| | - Silvio Rohm
- Center of Surgery, Department for Visceral, Transplant, Thoracic, and Vascular Surgery, University of Leipzig, Leipzig, Germany
- Center of Surgery, Department for Vascular Surgery, Diakonissen Hospital of Leipzig, Leipzig, Germany
| | - Ronald Biemann
- Institute of Clinical Chemistry and Laboratory Medicine, University of Leipzig, Leipzig, Germany
| | - Benjamin Sandner
- Division of Endocrinology and Diabetes, Department of Internal Medicine, University of Leipzig, Leipzig, Germany
| | - Anke Tönjes
- Division of Endocrinology and Diabetes, Department of Internal Medicine, University of Leipzig, Leipzig, Germany
| | - Graeme Eisenhofer
- TU Dresden, Medical Clinic III, University Hospital Carl Gustav Carus, Dresden, Germany
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Schürfeld R, Baratashvili E, Würfel M, Blüher M, Stumvoll M, Tönjes A, Ebert T. Circulating acyl-CoA-binding protein/diazepam-binding inhibitor in gestational diabetes mellitus. Reprod Biol Endocrinol 2023; 21:96. [PMID: 37872629 PMCID: PMC10591366 DOI: 10.1186/s12958-023-01152-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/12/2023] [Accepted: 10/13/2023] [Indexed: 10/25/2023] Open
Abstract
BACKGROUND Acyl-CoA-binding protein (ACBP)/diazepam-binding inhibitor has recently been characterized as an endocrine factor affecting energy balance and lipid metabolism. However, regulation of ACBP in women with gestational diabetes mellitus (GDM) during pregnancy, as well as postpartum, has not been investigated, so far. METHODS ACBP was quantified in 74 women with GDM and 74 healthy, gestational age-matched, pregnant controls using an enzyme-linked immunosorbent assay. Furthermore, ACBP was quantified post-partum in 82 women (i.e. 41 women with previous GDM vs. 41 previous control women). ACBP was related to measures of obesity, hypertension, glucose and lipid metabolism, renal function, and inflammation during pregnancy and postpartum. RESULTS During pregnancy, median [interquartile range] ACBP levels were not significantly different in women with GDM (40.9 [40.0] µg/l) compared to healthy, pregnant controls (29.1 [32.3] µg/l) (p = 0.215). ACBP serum concentrations increased from 30.3 [40.5] µg/l during pregnancy to 59.7 [33.2] µg/l after pregnancy in the entire cohort (p < 0.001). This observed elevation was consistent across both subgroups of women, those with prior GDM and those without. Multivariate analysis revealed that homeostasis model assessment of beta cell function (HOMA2-B) and creatinine positively and independently correlated with serum ACBP after pregnancy, while multivariate analysis during pregnancy showed no significant correlations. CONCLUSIONS Circulating ACBP is not a marker of GDM status, but ACBP is decreased during pregnancy, irrespective of GDM status. Furthermore, ACBP is related to beta cell function and renal markers in women after pregnancy.
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Affiliation(s)
- Robin Schürfeld
- Medical Department III - Endocrinology, University Hospital Leipzig, 04103, Nephrology, Rheumatology, Leipzig, Germany.
| | - Ekaterine Baratashvili
- Medical Department III - Endocrinology, University Hospital Leipzig, 04103, Nephrology, Rheumatology, Leipzig, Germany
| | - Marleen Würfel
- Medical Department III - Endocrinology, University Hospital Leipzig, 04103, Nephrology, Rheumatology, Leipzig, Germany
| | - Matthias Blüher
- Helmholtz Institute for Metabolic, Obesity and Vascular Research (HI-MAG, Helmholtz Zentrum München at the University of Leipzig and University Hospital, Leipzig, Germany
| | - Michael Stumvoll
- Medical Department III - Endocrinology, University Hospital Leipzig, 04103, Nephrology, Rheumatology, Leipzig, Germany
| | - Anke Tönjes
- Medical Department III - Endocrinology, University Hospital Leipzig, 04103, Nephrology, Rheumatology, Leipzig, Germany
| | - Thomas Ebert
- Medical Department III - Endocrinology, University Hospital Leipzig, 04103, Nephrology, Rheumatology, Leipzig, Germany
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Schürfeld R, Sandner B, Hoffmann A, Klöting N, Baratashvili E, Nowicki M, Paeschke S, Kosacka J, Kralisch S, Bachmann A, Frille A, Dietel A, Stolzenburg JU, Blüher M, Zhang MZ, Harris RC, Isermann B, Stumvoll M, Tönjes A, Ebert T. Renal function is a major predictor of circulating acyl-CoA-binding protein/diazepam-binding inhibitor. Front Endocrinol (Lausanne) 2023; 14:1152444. [PMID: 37288304 PMCID: PMC10242139 DOI: 10.3389/fendo.2023.1152444] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/27/2023] [Accepted: 05/09/2023] [Indexed: 06/09/2023] Open
Abstract
Objective Acyl-CoA-binding protein (ACBP)/diazepam-binding inhibitor has lately been described as an endocrine factor affecting food intake and lipid metabolism. ACBP is dysregulated in catabolic/malnutrition states like sepsis or systemic inflammation. However, regulation of ACBP has not been investigated in conditions with impaired kidney function, so far. Design/methods Serum ACBP concentrations were investigated by enzyme-linked immunosorbent assay i) in a cohort of 60 individuals with kidney failure (KF) on chronic haemodialysis and compared to 60 individuals with a preserved kidney function; and ii) in a human model of acute kidney dysfunction (AKD). In addition, mACBP mRNA expression was assessed in two CKD mouse models and in two distinct groups of non-CKD mice. Further, mRNA expression of mACBP was measured in vitro in isolated, differentiated mouse adipocytes - brown and white - after exposure to the uremic agent indoxyl sulfate. Results Median [interquartile range] serum ACBP was almost 20-fold increased in KF (514.0 [339.3] µg/l) compared to subjects without KF (26.1 [39.1] µg/l) (p<0.001). eGFR was the most important, inverse predictor of circulating ACBP in multivariate analysis (standardized β=-0.839; p<0.001). Furthermore, AKD increased ACBP concentrations almost 3-fold (p<0.001). Increased ACBP levels were not caused by augmented mACBP mRNA expression in different tissues of CKD mice in vivo or in indoxyl sulfate-treated adipocytes in vitro. Conclusions Circulating ACBP inversely associates with renal function, most likely through renal retention of the cytokine. Future studies need to investigate ACBP physiology in malnutrition-related disease states, such as CKD, and to adjust for markers of renal function.
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Affiliation(s)
- Robin Schürfeld
- Medical Department III – Endocrinology, Nephrology, Rheumatology, University of Leipzig Medical Center, Leipzig, Germany
| | - Benjamin Sandner
- Medical Department III – Endocrinology, Nephrology, Rheumatology, University of Leipzig Medical Center, Leipzig, Germany
| | - Annett Hoffmann
- Medical Department III – Endocrinology, Nephrology, Rheumatology, University of Leipzig Medical Center, Leipzig, Germany
- Department of General, Visceral, Transplant, Vascular and Pediatric Surgery, University Hospital Würzburg, Würzburg, Germany
| | - Nora Klöting
- Helmholtz Institute for Metabolic, Obesity and Vascular Research of the Helmholtz Zentrum München at the University of Leipzig and University Hospital, Leipzig, Germany
| | - Ekaterine Baratashvili
- Medical Department III – Endocrinology, Nephrology, Rheumatology, University of Leipzig Medical Center, Leipzig, Germany
- Department of Cardiology, Angiology and Internal Intensive-Care Medicine, Klinikum St. Georg, Leipzig, Germany
| | - Marcin Nowicki
- Institute of Anatomy, University of Leipzig, Leipzig, Germany
| | - Sabine Paeschke
- Institute of Anatomy, University of Leipzig, Leipzig, Germany
| | - Joanna Kosacka
- Department of Visceral, Transplant, Thoracic and Vascular Surgery, University of Leipzig Medical Center, Leipzig, Germany
| | - Susan Kralisch
- Medical Department III – Endocrinology, Nephrology, Rheumatology, University of Leipzig Medical Center, Leipzig, Germany
| | - Anette Bachmann
- Medical Department III – Endocrinology, Nephrology, Rheumatology, University of Leipzig Medical Center, Leipzig, Germany
| | - Armin Frille
- Department of Respiratory Medicine, University Hospital Leipzig, University of Leipzig, Leipzig, Germany
| | - Anja Dietel
- Department of Urology, University of Leipzig, Leipzig, Germany
| | | | - Matthias Blüher
- Medical Department III – Endocrinology, Nephrology, Rheumatology, University of Leipzig Medical Center, Leipzig, Germany
- Helmholtz Institute for Metabolic, Obesity and Vascular Research of the Helmholtz Zentrum München at the University of Leipzig and University Hospital, Leipzig, Germany
| | - Ming-Zhi Zhang
- Division of Nephrology, Department of Medicine, Vanderbilt University School of Medicine, Nashville, TN, United States
- Department of Medicine, Nashville Veterans Affairs Hospital, Vanderbilt University School of Medicine, Nashville, TN, United States
| | - Raymond C. Harris
- Division of Nephrology, Department of Medicine, Vanderbilt University School of Medicine, Nashville, TN, United States
- Department of Medicine, Nashville Veterans Affairs Hospital, Vanderbilt University School of Medicine, Nashville, TN, United States
| | - Berend Isermann
- Institute of Laboratory Medicine, Clinical Chemistry, and Molecular Diagnostics, University Hospital Leipzig, Leipzig, Germany
| | - Michael Stumvoll
- Medical Department III – Endocrinology, Nephrology, Rheumatology, University of Leipzig Medical Center, Leipzig, Germany
| | - Anke Tönjes
- Medical Department III – Endocrinology, Nephrology, Rheumatology, University of Leipzig Medical Center, Leipzig, Germany
| | - Thomas Ebert
- Medical Department III – Endocrinology, Nephrology, Rheumatology, University of Leipzig Medical Center, Leipzig, Germany
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Schürfeld R, Ebert T. [Tackling diabetes and nephropathy together]. MMW Fortschr Med 2023; 165:34-41. [PMID: 37081351 DOI: 10.1007/s15006-023-2446-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/22/2023]
Affiliation(s)
- Robin Schürfeld
- Klinik für Endokrinologie, Nephrologie und Rheumatologie, Universitätsklinikum Leipzig, Liebigstraße 20, 04103, Leipzig, Deutschland.
| | - Thomas Ebert
- Klinik für Endokrinologie, Nephrologie und Rheumatologie, Universitätsklinikum Leipzig, Liebigstraße 20, 04103, Leipzig, Deutschland
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