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Aichelman HE, Huzar AK, Wuitchik DM, Atherton KF, Wright RM, Dixon G, Schlatter E, Haftel N, Davies SW. Symbiosis modulates gene expression of symbionts, but not coral hosts, under thermal challenge. Mol Ecol 2024; 33:e17318. [PMID: 38488669 DOI: 10.1111/mec.17318] [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: 11/22/2023] [Revised: 02/23/2024] [Accepted: 03/01/2024] [Indexed: 04/09/2024]
Abstract
Increasing ocean temperatures are causing dysbiosis between coral hosts and their symbionts. Previous work suggests that coral host gene expression responds more strongly to environmental stress compared to their intracellular symbionts; however, the causes and consequences of this phenomenon remain untested. We hypothesized that symbionts are less responsive because hosts modulate symbiont environments to buffer stress. To test this hypothesis, we leveraged the facultative symbiosis between the scleractinian coral Oculina arbuscula and its symbiont Breviolum psygmophilum to characterize gene expression responses of both symbiotic partners in and ex hospite under thermal challenges. To characterize host and in hospite symbiont responses, symbiotic and aposymbiotic O. arbuscula were exposed to three treatments: (1) control (18°C), (2) heat (32°C), and (3) cold (6°C). This experiment was replicated with B. psygmophilum cultured from O. arbuscula to characterize ex hospite symbiont responses. Both thermal challenges elicited classic environmental stress responses (ESRs) in O. arbuscula regardless of symbiotic state, with hosts responding more strongly to cold challenge. Hosts also exhibited stronger responses than in hospite symbionts. In and ex hospite B. psygmophilum both down-regulated gene ontology pathways associated with photosynthesis under thermal challenge; however, ex hospite symbionts exhibited greater gene expression plasticity and differential expression of genes associated with ESRs. Taken together, these findings suggest that O. arbuscula hosts may buffer environments of B. psygmophilum symbionts; however, we outline the future work needed to confirm this hypothesis.
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Affiliation(s)
| | - Alexa K Huzar
- Department of Biology, Boston University, Boston, Massachusetts, USA
| | - Daniel M Wuitchik
- Department of Biology, Boston University, Boston, Massachusetts, USA
| | | | - Rachel M Wright
- Department of Biology, Boston University, Boston, Massachusetts, USA
| | - Groves Dixon
- Department of Integrative Biology, University of Texas at Austin, Austin, Texas, USA
| | - E Schlatter
- Department of Biology, Boston University, Boston, Massachusetts, USA
| | - Nicole Haftel
- Department of Biology, Boston University, Boston, Massachusetts, USA
| | - Sarah W Davies
- Department of Biology, Boston University, Boston, Massachusetts, USA
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Steinbüchel M, Menne J, Schröter R, Neugebauer U, Schlatter E, Ciarimboli G. Regulation of Transporters for Organic Cations by High Glucose. Int J Mol Sci 2023; 24:14051. [PMID: 37762353 PMCID: PMC10531077 DOI: 10.3390/ijms241814051] [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: 08/01/2023] [Revised: 09/08/2023] [Accepted: 09/11/2023] [Indexed: 09/29/2023] Open
Abstract
Endogenous positively charged organic substances, including neurotransmitters and cationic uremic toxins, as well as exogenous organic cations such as the anti-diabetic medication metformin, serve as substrates for organic cation transporters (OCTs) and multidrug and toxin extrusion proteins (MATEs). These proteins facilitate their transport across cell membranes. Vectorial transport through the OCT/MATE axis mediates the hepatic and renal excretion of organic cations, regulating their systemic and local concentrations. Organic cation transporters are part of the remote sensing and signaling system, whose activity can be regulated to cope with changes in the composition of extra- and intracellular fluids. Glucose, as a source of energy, can also function as a crucial signaling molecule, regulating gene expression in various organs and tissues. Its concentration in the blood may fluctuate in specific physiological and pathophysiological conditions. In this work, the regulation of the activity of organic cation transporters was measured by incubating human embryonic kidney cells stably expressing human OCT1 (hOCT1), hOCT2, or hMATE1 with high glucose concentrations (16.7 mM). Incubation with this high glucose concentration for 48 h significantly stimulated the activity of hOCT1, hOCT2, and hMATE1 by increasing their maximal velocity (Vmax), but without significantly changing their affinity for the substrates. These effects were independent of changes in osmolarity, as the addition of equimolar concentrations of mannitol did not alter transporter activity. The stimulation of transporter activity was associated with a significant increase in transporter mRNA expression. Inhibition of the mechanistic target of rapamycin (mTOR) kinase with Torin-1 suppressed the transporter stimulation induced by incubation with 16.7 mM glucose. Focusing on hOCT2, it was shown that incubation with 16.7 mM glucose increased hOCT2 protein expression in the plasma membrane. Interestingly, an apparent trend towards higher hOCT2 mRNA expression was observed in kidneys from diabetic patients, a pathology characterized by high serum glucose levels. Due to the small number of samples from diabetic patients (three), this observation must be interpreted with caution. In conclusion, incubation for 48 h with a high glucose concentration of 16.7 mM stimulated the activity and expression of organic cation transporters compared to those measured in the presence of 5.6 mM glucose. This stimulation by a diabetic environment could increase cellular uptake of the anti-diabetic drug metformin and increase renal tubular secretion of organic cations in an early stage of diabetes.
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Affiliation(s)
| | | | | | | | | | - Giuliano Ciarimboli
- Experimental Nephrology, Department of Internal Medicine D, University Hospital Münster, 48149 Münster, Germany; (M.S.); (J.M.); (R.S.); (U.N.); (E.S.)
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3
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Schlatter E, Klawon C, Webb C, Buston P. Heritability of dispersal‐related larval traits in the clown anemonefish
Amphiprion percula. Ecol Evol 2022; 12:e9541. [PMCID: PMC9702578 DOI: 10.1002/ece3.9541] [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] [Received: 04/20/2022] [Revised: 10/31/2022] [Accepted: 11/07/2022] [Indexed: 11/29/2022] Open
Affiliation(s)
| | | | - Colleen Webb
- Colorado State University Fort Collins Colorado USA
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4
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Desrochers L, Branconi R, Schlatter E, Dent B, Buston P. Sensory cues underlying competitive growth in the clown anemonefish (Amphiprion percula). Behav Processes 2020; 181:104276. [PMID: 33091543 DOI: 10.1016/j.beproc.2020.104276] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Revised: 10/01/2020] [Accepted: 10/15/2020] [Indexed: 01/09/2023]
Abstract
In some animal societies, access to breeding depends on the individual's position in a hierarchy, which often depends on an individual's size. In such societies, individuals may try to outgrow one another to attain a higher rank by engaging in a form of strategic growth (competitive growth). This suggests that members of the hierarchy can track changes in the growth and size of potential competitors and respond accordingly. The clown anemonefish, Amphiprion percula, is one species known to exhibit competitive growth at the initiation of size hierarchies. Here, we use 5 combinations of sensory cues to determine which cues must be available for individuals to engage in competitive growth. Our results show that mechanosensory (pressure and/or touch) cues or unobstructed interactions are necessary for competitive growth to occur. This study provides an understanding of the relationship between sensory cues and phenotypic responses to different social contexts.
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Affiliation(s)
- Leah Desrochers
- Boston University, 5 Cummington Mall, Boston, MA, 02115, USA.
| | | | - E Schlatter
- Boston University, 5 Cummington Mall, Boston, MA, 02115, USA.
| | - Brianne Dent
- Boston University, 5 Cummington Mall, Boston, MA, 02115, USA.
| | - Peter Buston
- Boston University, 5 Cummington Mall, Boston, MA, 02115, USA.
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5
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Harrach S, Barz V, Pap T, Pavenstädt H, Schlatter E, Edemir B, Distler J, Ciarimboli G, Bertrand J. Notch Signaling Activity Determines Uptake and Biological Effect of Imatinib in Systemic Sclerosis Dermal Fibroblasts. J Invest Dermatol 2018; 139:439-447. [PMID: 30273596 DOI: 10.1016/j.jid.2018.08.021] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Revised: 08/14/2018] [Accepted: 08/21/2018] [Indexed: 02/08/2023]
Abstract
Tyrosine kinase inhibitors have emerged as a therapeutic option for rheumatic diseases such as systemic sclerosis (SSc). Because tyrosine kinases like c-Abl kinase are important for fibroblast activation and fibrosis development in SSc, the c-Abl inhibitor imatinib was proposed for SSc treatment. Transporters for organic cations have become increasingly recognized as an important determinant for uptake and efficacy of tyrosine kinase inhibitors. Therefore, we investigated the role of organic cation transporters in the uptake of imatinib. Moreover, the influence of important SSc pathogenetic factors, like PDGF and Notch pathway activation on these uptake processes, has been studied. We showed that organic cation transporters OCT1-3, novel organic cation transporters OCTN1/2, and the multidrug and toxin extrusion protein MATE1 are expressed in healthy dermal and SSc fibroblasts. Decreased expression levels of MATE1 and decreased imatinib uptake were measured in SSc fibroblasts. In small interfering RNA experiments, MATE1 was identified as key transporter for imatinib uptake and biological effect in dermal fibroblasts. Furthermore, PDGF reduced imatinib uptake by decreasing MATE1 expression in SSc fibroblasts, but not in healthy fibroblasts. Blocking the Notch pathway in SSc fibroblasts increased MATE1 transporter expression and imatinib uptake. In conclusion, MATE1-mediated transport governs therapeutic efficacy of imatinib in SSc.
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Affiliation(s)
- Saliha Harrach
- Institute of Experimental Musculoskeletal Medicine, Department of Internal Medicine D, University Hospital Muenster, Germany; Experimental Nephrology, Department of Internal Medicine D, University Hospital Muenster, Germany
| | - Vivien Barz
- Experimental Nephrology, Department of Internal Medicine D, University Hospital Muenster, Germany
| | - Thomas Pap
- Institute of Experimental Musculoskeletal Medicine, Department of Internal Medicine D, University Hospital Muenster, Germany
| | - Hermann Pavenstädt
- Experimental Nephrology, Department of Internal Medicine D, University Hospital Muenster, Germany
| | - Eberhard Schlatter
- Experimental Nephrology, Department of Internal Medicine D, University Hospital Muenster, Germany
| | - Bayram Edemir
- Department of Internal Medicine IV, Hematology and Oncology, University Hospital Halle (Saale), Germany
| | - Jörg Distler
- Rheumatology and Immunology, Medical Clinic 3, University Hospital Erlangen, Erlangen, Germany
| | - Giuliano Ciarimboli
- Experimental Nephrology, Department of Internal Medicine D, University Hospital Muenster, Germany
| | - Jessica Bertrand
- Department of Orthopaedic Surgery, Otto-von-Guericke University Magdeburg, Germany.
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6
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Kantauskaite M, Hucke A, Hirsch B, Schlatter E, Ciarimboli G. [PP.17.01] ACTIVATION OF RENIN-ANGIOTENSIN SYSTEM STIMULATES THE ORGANIC CATION TRANSPORTER 2 AND INCREASES CISPLATIN TOXICITY. J Hypertens 2017. [DOI: 10.1097/01.hjh.0000523646.75270.7f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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7
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Kentrup D, Bovenkamp P, Busch A, Schuette-Nuetgen K, Pawelski H, Pavenstädt H, Schlatter E, Herrmann KH, Reichenbach JR, Löffler B, Heitplatz B, Van Marck V, Yadav NN, Liu G, van Zijl PCM, Reuter S, Hoerr V. GlucoCEST magnetic resonance imaging in vivo may be diagnostic of acute renal allograft rejection. Kidney Int 2017; 92:757-764. [PMID: 28709641 DOI: 10.1016/j.kint.2017.04.015] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2016] [Revised: 03/20/2017] [Accepted: 04/06/2017] [Indexed: 11/29/2022]
Abstract
Acute cellular renal allograft rejection (AR) frequently occurs after kidney transplantations. It is a sterile T-cell mediated inflammation leading to increased local glucose metabolism. Here we demonstrate in an allogeneic model of Brown Norway rat kidneys transplanted into uninephrectomized Lewis rats the successful implementation of the recently developed glucose chemical exchange saturation transfer (glucoCEST) magnetic resonance imaging. This technique is a novel method to assess and differentiate AR. Renal allografts undergoing AR showed significantly increased glucoCEST contrast ratios of cortex to medulla of 1.61 compared to healthy controls (1.02), syngeneic Lewis kidney to Lewis rat transplants without rejection (0.92), kidneys with ischemia reperfusion injury (0.99) and kidneys affected by cyclosporine A toxicity (1.10). Receiver operating characteristic curve analysis showed an area under the curve value of 0.92, and the glucoCEST contrast ratio predicted AR with a sensitivity of 100% and a specificity of 69% at a threshold level over 1.08. In defined animal models of kidney injuries, the glucoCEST contrast ratios of cortex to medulla correlated positively with mRNA expression levels of T-cell markers (CD3, CD4, CD8a/b), but did not correlate to impaired renal perfusion. Thus, the glucoCEST parameter may be valuable for the assessment and follow up treatment of AR.
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Affiliation(s)
- Dominik Kentrup
- Medical Clinic D, University of Muenster, Albert-Schweitzer Campus 1, 48149 Muenster, Germany
| | - Philipp Bovenkamp
- Department of Clinical Radiology, University Hospital Muenster, Albert-Schweitzer Campus 1, 48149 Muenster, Germany
| | - Annika Busch
- Department of Clinical Radiology, University Hospital Muenster, Albert-Schweitzer Campus 1, 48149 Muenster, Germany
| | | | - Helga Pawelski
- Medical Clinic D, University of Muenster, Albert-Schweitzer Campus 1, 48149 Muenster, Germany
| | - Hermann Pavenstädt
- Medical Clinic D, University of Muenster, Albert-Schweitzer Campus 1, 48149 Muenster, Germany
| | - Eberhard Schlatter
- Medical Clinic D, University of Muenster, Albert-Schweitzer Campus 1, 48149 Muenster, Germany
| | - Karl-Heinz Herrmann
- Medical Physics Group, Institute of Diagnostic and Interventional Radiology, Jena University Hospital, Friedrich-Schiller-University Jena, Philosophenweg 3, 07743 Jena, Germany
| | - Jürgen R Reichenbach
- Medical Physics Group, Institute of Diagnostic and Interventional Radiology, Jena University Hospital, Friedrich-Schiller-University Jena, Philosophenweg 3, 07743 Jena, Germany
| | - Bettina Löffler
- Institute of Medical Microbiology, Jena University Hospital, Erlanger Allee 101, 07747 Jena, Germany
| | - Barbara Heitplatz
- Department of Pathology, University of Muenster, Albert-Schweitzer Campus 1, 48149 Muenster, Germany
| | - Veerle Van Marck
- Department of Pathology, University of Muenster, Albert-Schweitzer Campus 1, 48149 Muenster, Germany
| | - Nirbhay N Yadav
- Russel H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, 1800 Orleans St., Baltimore, Maryland 21287, USA; F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Research Institute, 707 N. Broadway, Baltimore, Maryland 21205, USA
| | - Guanshu Liu
- Russel H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, 1800 Orleans St., Baltimore, Maryland 21287, USA; F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Research Institute, 707 N. Broadway, Baltimore, Maryland 21205, USA
| | - Peter C M van Zijl
- Russel H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, 1800 Orleans St., Baltimore, Maryland 21287, USA; F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Research Institute, 707 N. Broadway, Baltimore, Maryland 21205, USA
| | - Stefan Reuter
- Medical Clinic D, University of Muenster, Albert-Schweitzer Campus 1, 48149 Muenster, Germany.
| | - Verena Hoerr
- Department of Clinical Radiology, University Hospital Muenster, Albert-Schweitzer Campus 1, 48149 Muenster, Germany; Institute of Medical Microbiology, Jena University Hospital, Erlanger Allee 101, 07747 Jena, Germany.
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8
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Hu S, Leblanc AF, Gibson AA, Hong KW, Kim JY, Janke LJ, Li L, Vasilyeva A, Finkelstein DB, Sprowl JA, Sweet DH, Schlatter E, Ciarimboli G, Schellens J, Baker SD, Pabla N, Sparreboom A. Identification of OAT1/OAT3 as Contributors to Cisplatin Toxicity. Clin Transl Sci 2017; 10:412-420. [PMID: 28689374 PMCID: PMC5593168 DOI: 10.1111/cts.12480] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2017] [Accepted: 05/12/2017] [Indexed: 12/17/2022] Open
Abstract
Cisplatin is among the most widely used anticancer drugs and known to cause a dose‐limiting nephrotoxicity, which is partially dependent on the renal uptake carrier OCT2. We here report a previously unrecognized, OCT2‐independent pathway of cisplatin‐induced renal injury that is mediated by the organic anion transporters OAT1 and OAT3. Using transporter‐deficient mouse models, we found that this mechanism regulates renal uptake of a mercapturic acid metabolite of cisplatin that acts as a precursor of a potent nephrotoxin. The function of these two transport systems can be simultaneously inhibited by the tyrosine kinase inhibitor nilotinib through noncompetitive mechanisms, without compromising the anticancer properties of cisplatin. Collectively, our findings reveal a novel pathway that explains the fundamental basis of cisplatin‐induced nephrotoxicity, with potential implications for its therapeutic management.
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Affiliation(s)
- S Hu
- Division of Pharmaceutics and Pharmaceutical Chemistry, College of Pharmacy and Comprehensive Cancer Center, Ohio State University, Columbus, Ohio, USA
| | - A F Leblanc
- Division of Pharmaceutics and Pharmaceutical Chemistry, College of Pharmacy and Comprehensive Cancer Center, Ohio State University, Columbus, Ohio, USA
| | - A A Gibson
- Division of Pharmaceutics and Pharmaceutical Chemistry, College of Pharmacy and Comprehensive Cancer Center, Ohio State University, Columbus, Ohio, USA
| | - K W Hong
- Division of Pharmaceutics and Pharmaceutical Chemistry, College of Pharmacy and Comprehensive Cancer Center, Ohio State University, Columbus, Ohio, USA
| | - J Y Kim
- Division of Pharmaceutics and Pharmaceutical Chemistry, College of Pharmacy and Comprehensive Cancer Center, Ohio State University, Columbus, Ohio, USA
| | - L J Janke
- Department of Pathology, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - L Li
- Department of Pharmaceutical Sciences, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - A Vasilyeva
- Department of Pharmaceutical Sciences, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - D B Finkelstein
- Computational Biology, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - J A Sprowl
- Department of Pharmaceutical, Social and Administrative Sciences, School of Pharmacy, D'Youville College, Buffalo, New York, USA
| | - D H Sweet
- Department of Pharmaceutics, School of Pharmacy, Virginia Commonwealth University, Richmond, Virginia, USA
| | - E Schlatter
- Medical Clinic D, Experimental Nephrology, Münster Medical Faculty, Münster, Germany
| | - G Ciarimboli
- Medical Clinic D, Experimental Nephrology, Münster Medical Faculty, Münster, Germany
| | - Jhm Schellens
- Division of Molecular Pathology, The Netherlands Cancer Institute, Amsterdam, the Netherlands
| | - S D Baker
- Division of Pharmaceutics and Pharmaceutical Chemistry, College of Pharmacy and Comprehensive Cancer Center, Ohio State University, Columbus, Ohio, USA
| | - N Pabla
- Division of Pharmaceutics and Pharmaceutical Chemistry, College of Pharmacy and Comprehensive Cancer Center, Ohio State University, Columbus, Ohio, USA
| | - A Sparreboom
- Division of Pharmaceutics and Pharmaceutical Chemistry, College of Pharmacy and Comprehensive Cancer Center, Ohio State University, Columbus, Ohio, USA
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Schulze U, Brast S, Grabner A, Albiker C, Snieder B, Holle S, Schlatter E, Schröter R, Pavenstädt H, Herrmann E, Lambert C, Spoden GA, Florin L, Saftig P, Ciarimboli G. Tetraspanin CD63 controls basolateral sorting of organic cation transporter 2 in renal proximal tubules. FASEB J 2016; 31:1421-1433. [DOI: 10.1096/fj.201600901r] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2016] [Accepted: 12/12/2016] [Indexed: 12/19/2022]
Affiliation(s)
- Ulf Schulze
- Medizinische Klinik D, Experimentelle NephrologieWestfälische Wilhelms–Universität Münster Germany
| | - Sabine Brast
- Medizinische Klinik D, Experimentelle NephrologieWestfälische Wilhelms–Universität Münster Germany
| | - Alexander Grabner
- Medizinische Klinik D, Experimentelle NephrologieWestfälische Wilhelms–Universität Münster Germany
| | - Christian Albiker
- Medizinische Klinik D, Experimentelle NephrologieWestfälische Wilhelms–Universität Münster Germany
| | - Beatrice Snieder
- Medizinische Klinik D, Experimentelle NephrologieWestfälische Wilhelms–Universität Münster Germany
| | - Svenja Holle
- Medizinische Klinik D, Experimentelle NephrologieWestfälische Wilhelms–Universität Münster Germany
| | - Eberhard Schlatter
- Medizinische Klinik D, Experimentelle NephrologieWestfälische Wilhelms–Universität Münster Germany
| | - Rita Schröter
- Medizinische Klinik D, Experimentelle NephrologieWestfälische Wilhelms–Universität Münster Germany
| | - Hermann Pavenstädt
- Medizinische Klinik D, Experimentelle NephrologieWestfälische Wilhelms–Universität Münster Germany
| | - Edwin Herrmann
- Klinik und Poliklinik für UrologieWestfälische Wilhelms–Universität Münster Germany
| | - Carsten Lambert
- Institut für Medizinische Mikrobiologie und HygieneJohannes Gutenberg–Universität Mainz Germany
| | - Gilles A. Spoden
- Institut für Medizinische Mikrobiologie und HygieneJohannes Gutenberg–Universität Mainz Germany
| | - Luise Florin
- Institut für Medizinische Mikrobiologie und HygieneJohannes Gutenberg–Universität Mainz Germany
| | - Paul Saftig
- Biochemisches Institut, Medizinische FakultätChristian‐Albrechts–Universität Kiel Germany
| | - Giuliano Ciarimboli
- Medizinische Klinik D, Experimentelle NephrologieWestfälische Wilhelms–Universität Münster Germany
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10
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Schulze Blasum B, Schröter R, Neugebauer U, Hofschröer V, Pavenstädt H, Ciarimboli G, Schlatter E, Edemir B. The kidney-specific expression of genes can be modulated by the extracellular osmolality. FASEB J 2016; 30:3588-3597. [PMID: 27464968 DOI: 10.1096/fj.201600319r] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Accepted: 07/05/2016] [Indexed: 12/29/2022]
Abstract
With this study, we wanted to prove the hypothesis that the unique extracellular osmolality within the renal medulla modulates a specific gene expression pattern. The physiologic functions of the kidneys are mediated by the segment-specific expression of key proteins. So far, we have limited knowledge about the mechanisms that control this gene expression pattern. The hyperosmolality in the renal medullary interstitium is of major importance as a driving force for urine concentration. We made use of primarily cultured rat renal inner medullary collecting-duct cells and microarray analysis to identify genes affected by the environmental osmolality of the culture medium. We identified hundreds of genes that were either induced or repressed in expression by hyperosmolality in a time- and osmolality-dependent fashion. Further analysis demonstrated that many of them, physiologically, showed a kidney- and even collecting-duct-specific expression, including secreted proteins, kinases, and transcription factors. On the other hand, we identified factors, down-regulated in expression, that have a diuretic effect. In conclusion, the kidney is the only organ that has such a hyperosmotic environment, and study provides an excellent method for controlling tissue-specific gene expression.-Schulze Blasum, B., Schröter, R., Neugebauer, U., Hofschröer, V., Pavenstädt, H., Ciarimboli, G., Schlatter E., Edemir, B. The kidney-specific expression of genes can be modulated by the extracellular osmolality.
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Affiliation(s)
- Britta Schulze Blasum
- Department of Internal Medicine D, Experimental Nephrology, University of Münster, Münster, Germany
| | - Rita Schröter
- Department of Internal Medicine D, Experimental Nephrology, University of Münster, Münster, Germany
| | - Ute Neugebauer
- Department of Internal Medicine D, Experimental Nephrology, University of Münster, Münster, Germany
| | - Verena Hofschröer
- Institute of Physiology II, University of Münster, Münster, Germany; and
| | - Hermann Pavenstädt
- Department of Internal Medicine D, Experimental Nephrology, University of Münster, Münster, Germany
| | - Guiliano Ciarimboli
- Department of Internal Medicine D, Experimental Nephrology, University of Münster, Münster, Germany
| | - Eberhard Schlatter
- Department of Internal Medicine D, Experimental Nephrology, University of Münster, Münster, Germany
| | - Bayram Edemir
- Department of Internal Medicine D, Experimental Nephrology, University of Münster, Münster, Germany; Faculty of Medicine, Department of Hematology and Oncology, Faculty of Medicine, Martin Luther University Halle-Wittenberg, Halle (Saale), Germany
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11
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Grabner A, Kentrup D, Pawelski H, Mühlmeister M, Biermann C, Edemir B, Heitplatz B, Van Marck V, Bettinger T, Pavenstädt H, Schlatter E, Stypmann J, Tiemann K, Reuter S. Renal Contrast-Enhanced Sonography Findings in a Model of Acute Cellular Allograft Rejection. Am J Transplant 2016; 16:1612-9. [PMID: 26613381 DOI: 10.1111/ajt.13648] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2015] [Accepted: 11/22/2015] [Indexed: 01/25/2023]
Abstract
Noninvasive methods to diagnose and differentiate acute cellular rejection from acute tubular necrosis or acute calcineurin inhibitor toxicity are still missing. Because T lymphocytes play a decisive role in early states of rejection, we investigated the suitability and feasibility of antibody-mediated contrast-enhanced ultrasound by using microbubbles targeted to CD3(+) , CD4(+) , or CD8(+) T cells in different models of renal disease. In an established rat renal transplantation model, CD3-mediated ultrasound allows the detection of acute rejection as early as on postoperative day 2. Ultrasound signal intensities increased with the severity of inflammation. Further, an early response to therapy could be monitored by using contrast-enhanced sonography. Notably, acute tubular necrosis occurring after ischemia-reperfusion injury as well as acute calcineurin inhibitor toxicity could easily be differentiated. Finally, the quantified ultrasound signal correlated significantly with the number of infiltrating T cells obtained by histology and with CD3 mRNA levels, as well as with chemokine CXCL9, CXCL11, and CCL19 mRNA but not with KIM-1 mRNA expression, thereby representing the severity of graft inflammation but not the degree of kidney injury. In summary, we demonstrate that antibody-mediated contrast-enhanced ultrasound targeting T lymphocytes could be a promising tool for an easy and reproducible assessment of acute rejection after renal transplantation.
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Affiliation(s)
- A Grabner
- Department of Medicine D, Experimental Nephrology, University of Münster, Münster, Germany
| | - D Kentrup
- Department of Medicine D, Experimental Nephrology, University of Münster, Münster, Germany
| | - H Pawelski
- Department of Medicine D, Experimental Nephrology, University of Münster, Münster, Germany
| | - M Mühlmeister
- Department of Medicine D, Experimental Nephrology, University of Münster, Münster, Germany
| | - C Biermann
- Department of Medicine D, Experimental Nephrology, University of Münster, Münster, Germany
| | - B Edemir
- Department of Medicine, Hematology and Oncology, University of Halle, Halle, Germany
| | - B Heitplatz
- Department of Pathology, University of Münster, Münster, Germany
| | - V Van Marck
- Department of Pathology, University of Münster, Münster, Germany
| | | | - H Pavenstädt
- Department of Medicine D, Experimental Nephrology, University of Münster, Münster, Germany
| | - E Schlatter
- Department of Medicine D, Experimental Nephrology, University of Münster, Münster, Germany
| | - J Stypmann
- Department of Cardiovascular Medicine, University of Münster, Münster, Germany
| | - K Tiemann
- Department of Cardiology, Otypka Heart Center and Department of Nuclear Medicine, Technical University Munich, Munich, Germany
| | - S Reuter
- Department of Medicine D, Experimental Nephrology, University of Münster, Münster, Germany
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Grabner A, Kentrup D, Mühlmeister M, Pawelski H, Biermann C, Bettinger T, Pavenstädt H, Schlatter E, Tiemann K, Reuter S. Noninvasive Imaging of Acute Renal Allograft Rejection by Ultrasound Detection of Microbubbles Targeted to T-lymphocytes in Rats. Ultraschall Med 2016; 37:82-91. [PMID: 25919412 DOI: 10.1055/s-0034-1385796] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
PURPOSE We propose CD3-antibody-mediated contrast-enhanced ultrasonography using human T-lymphocytes for image-based diagnosis of acute allograft rejection (AR) established in a rat renal transplantation model. MATERIALS AND METHODS 15 minutes after tail vein injection of 30 × 10(6) human T-lymphocytes, contrast media/microbubbles conjugated with an anti-human CD3 antibody was applied to uni-nephrectomized 10-week-old allogeneically transplanted male rats (Lewis-Brown Norway (LBN) to Lewis, aTX) and ultrasound was performed to investigate the transplanted kidney as well as the native kidney. In vivo results were confirmed via immunohistochemical stainings of CD3 after post mortem dissection. Syngeneically transplanted rats (LBN to LBN, sTX), rats with ischemia/reperfusion injury (IRI, 45 min. warm ischemia), and rats subjected to acute cyclosporin A toxicity (CSA) (cyclosporine 50 mg/kg BW for 2 days i. p.) served as controls. RESULTS Accumulation of human T-lymphocytes was clearly detected by antibody-mediated sonography und was significantly increased in allografts undergoing AR (5.41 ± 1.32 A. U.) when compared to native control kidneys (0.70 ± 0.08 A. U.). CD3 signal intensity was low in native kidneys, sTX (0.99 ± 0.30 A. U.), CSA (0.10 ± 0.02 A. U.) and kidneys with IRI (0.46 ± 0.29 A. U.). Quantification of the ultrasound signal correlated significantly with the T-cell numbers obtained by immunohistochemical analysis (R2 = 0.57). CONCLUSION Contrast-enhanced sonography using CD3-antibodies is an option for quick and highly specific assessment of AR in a rat model of renal transplantation.
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Affiliation(s)
- A Grabner
- Department of Medicine D, Experimental Nephrology, University Hospital Münster, Germany
| | - D Kentrup
- Department of Medicine D, Experimental Nephrology, University Hospital Münster, Germany
| | - M Mühlmeister
- Department of Medicine D, Experimental Nephrology, University Hospital Münster, Germany
| | - H Pawelski
- Department of Medicine D, Experimental Nephrology, University Hospital Münster, Germany
| | - C Biermann
- Department of Medicine D, Experimental Nephrology, University Hospital Münster, Germany
| | - T Bettinger
- Bracco Suisse SA, Bracco Suisse SA, Geneva, Italy
| | - H Pavenstädt
- Department of Medicine D, Experimental Nephrology, University Hospital Münster, Germany
| | - E Schlatter
- Department of Medicine D, Experimental Nephrology, University Hospital Münster, Germany
| | - K Tiemann
- Department of Nuclear Medicine, Technical University Munich, Germany
| | - S Reuter
- Department of Medicine D, Experimental Nephrology, University Hospital Münster, Germany
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Lanvers-Kaminsky C, Sprowl JA, Malath I, Deuster D, Eveslage M, Schlatter E, Mathijssen RH, Boos J, Jürgens H, Am Zehnhoff-Dinnesen AG, Sparreboom A, Ciarimboli G. Human OCT2 variant c.808G>T confers protection effect against cisplatin-induced ototoxicity. Pharmacogenomics 2016; 16:323-32. [PMID: 25823781 DOI: 10.2217/pgs.14.182] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
AIM Assuming that genetic variants of the SLC22A2 and SLC31A1 transporter affect patients' susceptibility to cisplatin-induced ototoxicity, we compared the distribution of 11 SLC22A2 variants and the SLC31A1 variant rs10981694 between patients with and without cisplatin-induced ototoxicity. PATIENTS & METHODS Genotyping was performed in 64 pediatric patients and significant findings were re-evaluated in 66 adults. RESULTS The SLC22A2 polymorphism rs316019 (c.808G>T; Ser270Ala) was significantly associated with protection from cisplatin-induced ototoxicity in the pediatric (p = 0.022) and the adult cohort (p = 0.048; both: Fisher's exact test). This result was confirmed by multiple logistic regression analysis accounting for age which was identified as a relevant factor for ototoxicity as well (rs316019: OR [G/T vs G/G] = 0.12, p = 0.009; age: OR [per year]: 0.84, p = 0.02). CONCLUSION These results identified rs316019 as potential pharmacogenomic marker for cisplatin-induced ototoxicity and point to a critical role of SLC22A2 for cisplatin transport in humans and its contribution to the organ specific side effects of this drug. Original submitted 17 September 2014; Revision submitted 19 December 2014.
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Affiliation(s)
- Claudia Lanvers-Kaminsky
- Department of Pediatric Hematology & Oncology, University Children's Hospital of Muenster, Muenster, Germany
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Kentrup D, Busch A, Pawelski H, Schlatter E, Hoerr V, Reuter S. SP772NON-INVASIVE DETECTION OF ACUTE RENAL ALLOGRAFT REJECTION THROUGH GLUCOCEST MRI. Nephrol Dial Transplant 2015. [DOI: 10.1093/ndt/gfv201.05] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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Schindhelm K, Schlatter E, Schurek HJ, Stolte H. The isolated perfused rat kidney and uraemic middle molecules. Contrib Nephrol 2015; 19:191-200. [PMID: 7379537 DOI: 10.1159/000428778] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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17
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Schlatter E, Lustenberger N, Schütz R, Biela D, Stolte H. Experimental in vivo and in vitro studies in haemodialysis and haemofiltration. Contrib Nephrol 2015; 19:201-10. [PMID: 6991211 DOI: 10.1159/000428779] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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18
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Harrach S, Edemir B, Schlatter E, Pap T, Ciarimboli G, Bertrand J. A8.23 Carrier-mediated transport systems for specific targeting of tyrosine kinase signalling pathways in rheumatoid arthritis. Ann Rheum Dis 2015. [DOI: 10.1136/annrheumdis-2015-207259.208] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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Sprowl JA, Lancaster CS, Pabla N, Hermann E, Kosloske AM, Gibson AA, Li L, Zeeh D, Schlatter E, Janke LJ, Ciarimboli G, Sparreboom A. Cisplatin-induced renal injury is independently mediated by OCT2 and p53. Clin Cancer Res 2014; 20:4026-35. [PMID: 24916697 DOI: 10.1158/1078-0432.ccr-14-0319] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
PURPOSE Tubular secretion of cisplatin is abolished in mice deficient for the organic cation transporters Oct1 and Oct2 (Oct1/2(-/-)mice), and these animals are protected from severe cisplatin-induced kidney damage. Since tubular necrosis is not completely absent in Oct1/2(-/-)mice, we hypothesized that alternate pathways are involved in the observed injury. EXPERIMENTAL DESIGN Studies were done in wild-type, Oct1/2(-/-), or p53-deficient animals, all on an FVB background, receiving cisplatin intraperitoneally at 15 mg/kg. Cisplatin metabolites were analyzed using mass spectrometry, and gene expression was assessed using Affymetrix microarrays and RT-PCR arrays. RESULTS KEGG pathway analyses on kidneys from mice exposed to cisplatin revealed that the most significantly altered genes were associated with the p53 signaling network, including Cdnk1a and Mdm2, in both wild-type (P = 2.40 × 10(-11)) and Oct1/2(-/-)mice (P = 1.92 × 10(-8)). This was confirmed by demonstrating that homozygosity for a p53-null allele partially reduced renal tubular damage, whereas loss of p53 in Oct1/2(-/-)mice (p53(-/-)/Oct1/2(-/-)) completely abolished nephrotoxicity. We found that pifithrin-α, an inhibitor of p53-dependent transcriptional activation, inhibits Oct2 and can mimic the lack of nephrotoxicity observed in p53(-/-)/Oct1/2(-/-)mice. CONCLUSIONS These findings indicate that (i) the p53 pathway plays a crucial role in the kidney in response to cisplatin treatment and (ii) clinical exploration of OCT2 inhibitors may not lead to complete nephroprotection unless the p53 pathway is simultaneously antagonized.
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Affiliation(s)
| | | | | | | | | | | | - Lie Li
- Departments of Pharmaceutical Sciences and
| | - Dorothea Zeeh
- Medizinische Klinik D, Experimentelle Nephrologie, Universitätsklinikum Münster, Münster, Germany
| | - Eberhard Schlatter
- Medizinische Klinik D, Experimentelle Nephrologie, Universitätsklinikum Münster, Münster, Germany
| | - Laura J Janke
- Pathology, St. Jude Children's Research Hospital, Memphis, Tennessee; and
| | - Giuliano Ciarimboli
- Medizinische Klinik D, Experimentelle Nephrologie, Universitätsklinikum Münster, Münster, Germany
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Baumann D, Amann K, Schlatter E, Ciarimboli G, Kopp H, Müller M, Kluba T, Bakos G, Steinke I, Bunz H, Weyrich P, Artunc F. Terminales Nierenversagen nach Sarkomtherapie – Fall 3/2014. Dtsch Med Wochenschr 2014; 139:785. [DOI: 10.1055/s-0033-1360084] [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: 10/25/2022]
Affiliation(s)
- D. Baumann
- Medizinische Klinik, Universitätsklinikum Tübingen
| | - K. Amann
- Pathologisches Institut, Universitätsklinikum Erlangen
| | - E. Schlatter
- Medizinische Klinik D, Experimentelle Nephrologie, Universitätsklinikum Münster
| | - G. Ciarimboli
- Medizinische Klinik D, Experimentelle Nephrologie, Universitätsklinikum Münster
| | - H.G. Kopp
- Medizinische Klinik, Universitätsklinikum Tübingen
| | - M. Müller
- Medizinische Klinik, Universitätsklinikum Tübingen
| | - T. Kluba
- Orthopädische Klinik, Universitätsklinikum Tübingen
| | - G. Bakos
- Pathologisches Institut, Universitätsklinikum Tübingen
| | | | - H. Bunz
- Medizinische Klinik, Universitätsklinikum Tübingen
| | - P. Weyrich
- Medizinische Klinik, Universitätsklinikum Tübingen
| | - F. Artunc
- Medizinische Klinik, Universitätsklinikum Tübingen
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Massmann V, Edemir B, Schlatter E, Al-Monajjed R, Harrach S, Klassen P, Holle SK, Sindic A, Dobrivojevic M, Pavenstädt H, Ciarimboli G. The organic cation transporter 3 (OCT3) as molecular target of psychotropic drugs: transport characteristics and acute regulation of cloned murine OCT3. Pflugers Arch 2013; 466:517-27. [DOI: 10.1007/s00424-013-1335-8] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2013] [Revised: 08/05/2013] [Accepted: 08/09/2013] [Indexed: 01/11/2023]
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Grabner A, Kentrup D, Edemir B, Sirin Y, Pavenstädt H, Schlatter E, Schober O, Schäfers M, Schnöckel U, Reuter S. PET with 18F-FDG-labeled T lymphocytes for diagnosis of acute rat renal allograft rejection. J Nucl Med 2013; 54:1147-53. [PMID: 23670903 DOI: 10.2967/jnumed.112.109231] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
UNLABELLED We proposed small-animal PET with (18)F-FDG-labeled T lymphocytes as a new method for image-based diagnosis of acute allogeneic renal transplant rejection (AR) established in a rat model. METHODS One and 2 h after tail vein injection of 30 × 10(6) ex vivo (18)F-FDG-labeled human T cells into male 10-wk-old uninephrectomized, allogeneically transplanted rats (aTX; Lewis-brown Norway [LBN] to Lewis), whole-body radioactivity distribution was assessed in vivo by small-animal PET (postoperative day 4), and percentage injected dose (%ID) as a parameter of T-cell infiltration was assessed and compared between graft and native kidney. In vivo results were confirmed by autoradiography and staining of human CD3 after postmortem dissection. Syngeneically transplanted rats (sTX) (LBN to LBN), rats with ischemia-reperfusion injury (IRI) (45-min warm ischemia), and rats subjected to acute cyclosporine A (CSA) toxicity (50 mg/kg for 2 d intraperitoneally) served as controls. RESULTS The accumulation of labeled cells was significantly elevated in allografts with AR (1.07 ± 0.28 %ID), compared with native control kidneys (0.49 ± 0.18 %ID) (P < 0.0001). No differences were found among native controls, sTX, CSA toxicity, and kidneys with IRI. In vivo uptake of (18)F-FDG cells measured in the PET scanner correlated with results obtained by autoradiography, histologic evaluation, and polymerase chain reaction. CONCLUSION We proposed graft PET imaging using (18)F-FDG-labeled T cells as a new option to detect rat renal AR with a low dose of (18)F-FDG in a noninvasive, fast, and specific manner in rats.
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Affiliation(s)
- Alexander Grabner
- Department of Internal Medicine D, Experimental Nephrology, University of Münster, Münster, Germany
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23
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Ciarimboli G, Schröter R, Neugebauer U, Vollenbröker B, Gabriëls G, Brzica H, Sabolić I, Pietig G, Pavenstädt H, Schlatter E, Edemir B. Kidney transplantation down-regulates expression of organic cation transporters, which translocate β-blockers and fluoroquinolones. Mol Pharm 2013; 10:2370-80. [PMID: 23607617 DOI: 10.1021/mp4000234] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Kidney transplanted patients are often treated with immunosuppressive, antihypertensive, and antibiotic drugs such as cyclosporine A (CsA), β-blockers, and fluoroquinolones, respectively. Organic cation transporters (OCT) expressed in the basolateral membrane of proximal tubules represent an important drug excretion route. In this work, the renal expression of OCT after syngeneic and allogeneic kidney transplantation in rats with or without CsA immunosuppression was studied. Moreover, the interactions of CsA, β-blockers (pindolol/atenolol), and fluoroquinolones (ofloxacin/norfloxacin) with rOCT1, rOCT2, hOCT1, and hOCT2 in stably transfected HEK293-cells were studied. Kidney transplantation was associated with reduced expression of rOCT1, while rOCT2 showed only reduced expression after allogeneic transplantation. All drugs interacted subtype- and species-dependently with OCT. However, only atenolol, pindolol, and ofloxacin were transported by hOCT2, the main OCT in human kidneys. While CsA is not an OCT substrate, it exerts a short-term effect on OCT activity, changing their affinity for some substrates. In conclusion, appropriate drug dosing in transplanted patients is difficult partly because OCT are down-regulated and because concomitant CsA treatment may influence the affinity of the transporters. Moreover, drug-drug competition at the transporter can also alter drug excretion rate.
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Affiliation(s)
- Giuliano Ciarimboli
- Medizinische Klinik D, Experimentelle Nephrologie, Universitätsklinikum Münster, Albert-Schweitzer-Campus 1/A14, Münster D-48149, Germany
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Dimuccio V, Ranghino A, Basso E, Biancone L, Camussi G, Bussolati B, Grabner A, Kentrup D, Muehlmeister M, Pawelski H, Pavenstadt H, Schlatter E, Tiemann K, Reuter S. New perspectives in transplantation therapy. Nephrol Dial Transplant 2013. [DOI: 10.1093/ndt/gft185] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Grabner A, Kentrup D, Schnöckel U, Gabriëls G, Schröter R, Pavenstädt H, Schober O, Schlatter E, Schäfers M, Reuter S. Non-invasive imaging of acute allograft rejection after rat renal transplantation using 18F-FDG PET. J Vis Exp 2013:e4240. [PMID: 23644348 DOI: 10.3791/4240] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
The number of patients with end-stage renal disease, and the number of kidney allograft recipients continuously increases. Episodes of acute cellular allograft rejection (AR) are a negative prognostic factor for long-term allograft survival, and its timely diagnosis is crucial for allograft function (1). At present, AR can only be definitely diagnosed by core-needle biopsy, which, as an invasive method, bares significant risk of graft injury or even loss. Moreover, biopsies are not feasible in patients taking anticoagulant drugs and the limited sampling site of this technique may result in false negative results if the AR is focal or patchy. As a consequence, this gave rise to an ongoing search for new AR detection methods, which often has to be done in animals including the use of various transplantation models. Since the early 60s rat renal transplantation is a well-established experimental method for the examination and analysis of AR (2). We herein present in addition small animal positron emission tomography (PET) using (18)F-fluorodeoxyglucose (FDG) to assess AR in an allogeneic uninephrectomized rat renal transplantation model and propose graft FDG-PET imaging as a new option for a non-invasive, specific and early diagnosis of AR also for the human situation (3). Further, this method can be applied for follow-up to improve monitoring of transplant rejection (4).
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Affiliation(s)
- Alexander Grabner
- Department of Internal Medicine D, Experimental Nephrology, University of Münster.
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Jaureguiberry G, De la Dure-Molla M, Parry D, Quentric M, Himmerkus N, Koike T, Poulter J, Klootwijk E, Robinette SL, Howie AJ, Patel V, Figueres ML, Stanescu HC, Issler N, Nicholson JK, Bockenhauer D, Laing C, Walsh SB, McCredie DA, Povey S, Asselin A, Picard A, Coulomb A, Medlar AJ, Bailleul-Forestier I, Verloes A, Le Caignec C, Roussey G, Guiol J, Isidor B, Logan C, Shore R, Johnson C, Inglehearn C, Al-Bahlani S, Schmittbuhl M, Clauss F, Huckert M, Laugel V, Ginglinger E, Pajarola S, Spartà G, Bartholdi D, Rauch A, Addor MC, Yamaguti PM, Safatle HP, Acevedo AC, Martelli-Júnior H, dos Santos Netos PE, Coletta RD, Gruessel S, Sandmann C, Ruehmann D, Langman CB, Scheinman SJ, Ozdemir-Ozenen D, Hart TC, Hart PS, Neugebauer U, Schlatter E, Houillier P, Gahl WA, Vikkula M, Bloch-Zupan A, Bleich M, Kitagawa H, Unwin RJ, Mighell A, Berdal A, Kleta R. Nephrocalcinosis (enamel renal syndrome) caused by autosomal recessive FAM20A mutations. Nephron Clin Pract 2013; 122:1-6. [PMID: 23434854 PMCID: PMC3782194 DOI: 10.1159/000349989] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2013] [Accepted: 02/20/2013] [Indexed: 11/19/2022] Open
Abstract
Background/Aims Calcium homeostasis requires regulated cellular and interstitial systems interacting to modulate the activity and movement of this ion. Disruption of these systems in the kidney results in nephrocalcinosis and nephrolithiasis, important medical problems whose pathogenesis is incompletely understood. Methods We investigated 25 patients from 16 families with unexplained nephrocalcinosis and characteristic dental defects (amelogenesis imperfecta, gingival hyperplasia, impaired tooth eruption). To identify the causative gene, we performed genome-wide linkage analysis, exome capture, next-generation sequencing, and Sanger sequencing. Results All patients had bi-allelic FAM20A mutations segregating with the disease; 20 different mutations were identified. Conclusions This au-tosomal recessive disorder, also known as enamel renal syndrome, of FAM20A causes nephrocalcinosis and amelogenesis imperfecta. We speculate that all individuals with biallelic FAM20A mutations will eventually show nephrocalcinosis.
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Schmidt-Lauber C, Harrach S, Pap T, Fischer M, Victor M, Heitzmann M, Hansen U, Fobker M, Brand SM, Sindic A, Pavenstädt H, Edemir B, Schlatter E, Bertrand J, Ciarimboli G. Transport mechanisms and their pathology-induced regulation govern tyrosine kinase inhibitor delivery in rheumatoid arthritis. PLoS One 2012; 7:e52247. [PMID: 23284953 PMCID: PMC3527388 DOI: 10.1371/journal.pone.0052247] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2012] [Accepted: 11/16/2012] [Indexed: 01/20/2023] Open
Abstract
BACKGROUND Tyrosine kinase inhibitors (TKIs) are effective in treating malignant disorders and were lately suggested to have an impact on non-malignant diseases. However, in some inflammatory conditions like rheumatoid arthritis (RA) the in vivo effect seemed to be moderate. As most TKIs are taken up actively into cells by cell membrane transporters, this study aimed to evaluate the role of such transporters for the accumulation of the TKI Imatinib mesylates in RA synovial fibroblasts as well as their regulation under inflammatory conditions. METHODOLOGY/PRINCIPAL FINDINGS The transport and accumulation of Imatinib was investigated in transporter-transfected HEK293 cells and human RA synovial fibroblasts (hRASF). Transporter expression was quantified by qRT-PCR. In transfection experiments, hMATE1 showed the highest apparent affinity for Imatinib among all known Imatinib transporters. Experiments quantifying the Imatinib uptake in the presence of specific transporter inhibitors and after siRNA knockdown of hMATE1 indeed identified hMATE1 to mediate Imatinib transport in hRASF. The anti-proliferative effect of Imatinib on PDGF stimulated hRASF was quantified by cell counting and directly correlated with the uptake activity of hMATE1. Expression of hMATE1 was investigated by Western blot and immuno-fluorescence. Imatinib transport under disease-relevant conditions, such as an altered pH and following stimulation with different cytokines, was also investigated by HPLC. The uptake was significantly reduced by an acidic extracellular pH as well as by the cytokines TNFα, IL-1β and IL-6, which all decreased the expression of hMATE1-mRNA and protein. CONCLUSION/SIGNIFICANCE The regulation of Imatinib uptake via hMATE1 in hRASF and resulting effects on their proliferation may explain moderate in vivo effects on RA. Moreover, our results suggest that investigating transporter mediated drug processing under normal and pathological conditions is important for developing intracellular acting drugs used in inflammatory diseases.
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Affiliation(s)
- Christian Schmidt-Lauber
- Experimental Nephrology, Department of Internal Medicine D, University Hospital Münster, Münster, Germany
- Institute of Experimental Musculoskeletal Medicine, University Hospital Münster, Münster, Germany
| | - Saliha Harrach
- Experimental Nephrology, Department of Internal Medicine D, University Hospital Münster, Münster, Germany
- Institute of Experimental Musculoskeletal Medicine, University Hospital Münster, Münster, Germany
| | - Thomas Pap
- Institute of Experimental Musculoskeletal Medicine, University Hospital Münster, Münster, Germany
| | - Meike Fischer
- Experimental Nephrology, Department of Internal Medicine D, University Hospital Münster, Münster, Germany
| | - Marion Victor
- Experimental Nephrology, Department of Internal Medicine D, University Hospital Münster, Münster, Germany
| | - Marianne Heitzmann
- Institute of Experimental Musculoskeletal Medicine, University Hospital Münster, Münster, Germany
| | - Uwe Hansen
- Institute for Physiological Chemistry and Pathobiochemistry, University Hospital Münster, Münster, Germany
| | - Manfred Fobker
- Center of Laboratory Medicine, University Hospital Münster, Münster, Germany
| | - Stefan-Martin Brand
- Leibniz-Institute for Arteriosclerosis Research, University Hospital Münster, Münster, Germany
- Molecular Genetics of Cardiovascular Disease, Institute of Sports Medicine, University Hospital Münster, Münster, Germany
| | - Aleksandra Sindic
- Department of Physiology, Croatian Institute for Brain Research, University of Zagreb, Zagreb, Croatia
| | - Hermann Pavenstädt
- Experimental Nephrology, Department of Internal Medicine D, University Hospital Münster, Münster, Germany
| | - Bayram Edemir
- Experimental Nephrology, Department of Internal Medicine D, University Hospital Münster, Münster, Germany
| | - Eberhard Schlatter
- Experimental Nephrology, Department of Internal Medicine D, University Hospital Münster, Münster, Germany
| | - Jessica Bertrand
- Institute of Experimental Musculoskeletal Medicine, University Hospital Münster, Münster, Germany
| | - Giuliano Ciarimboli
- Experimental Nephrology, Department of Internal Medicine D, University Hospital Münster, Münster, Germany
- * E-mail:
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Edemir B, Jardzejewski M, Schlatter E. Variation of medium osmolalities induces changes in cilia related signalling pathways in primary cultured renal inner medullary collecting duct cells. Cilia 2012. [PMCID: PMC3555789 DOI: 10.1186/2046-2530-1-s1-p21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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Guckel D, Ciarimboli G, Pavenstädt H, Schlatter E. Regulation of organic cation transport in isolated mouse proximal tubules involves complex changes in protein trafficking and substrate affinity. Cell Physiol Biochem 2012; 30:269-81. [PMID: 22759973 DOI: 10.1159/000339063] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/14/2012] [Indexed: 11/19/2022] Open
Abstract
This study characterizes the complex mechanisms of acute regulation of organic cation (OC) transport across the basolateral membrane of isolated mouse proximal tubules. The fluorescent substrate ASP(+), 4-(-4-(dimethylamino) styryl-N-methylpyridinium, was used to quantify OC transport using a microtiter plate based fluorescence reader method. Inhibition of phosphatidylinositol-3-kinase, of p56 tyrosine kinase, stimulation of PKC and inhibition of PKA reduced ASP(+)-uptake. ASP(+)-kinetic and Dixon plot analyses revealed effects on transporter trafficking as explanation for the inhibition of ASP(+)-uptake by these pathways. Angiotensin II (AII) via stimulation of Ca(2+)/calmodulin increased ASP(+)-uptake. This effect aroused from an altered substrate affinity. Bafilomycin, an inhibitor of the vacuolar H(+)-ATPase and thus endosomal and lysosomal function, reduced ASP(+)-uptake, but did not prevent the AII effect on ASP(+)-uptake. Bafilomycin seemed to diminish the recycling rate of OCTs and hence to reduce the amount of transporters in the membrane. AII via Ca(2+)/calmodulin increased the substrate affinity of the remaining OCTs. The involvement of the cytoskeleton in acute regulation of OCTs became obvious as colchicine induced inhibition of microtubule polymerisation reduced ASP(+)-uptake. Acute regulation of mouse OCTs mostly involves changes in trafficking from and to the plasma membrane and only in the case of AII/CaM changes in substrate affinity.
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Affiliation(s)
- Denise Guckel
- Medizinische Klinik und Poliklinik D, Experimentelle Nephrologie, Universität Münster, Münster, Germany
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Adamczak M, Koleganova N, Nyengaard JR, Ritz E, Wiecek A, Slabiak Blaz N, Yi Chun DX, Alexandre H, Sandrine GS, Olivier T, Isabelle E, Christophe L, Guy T, Pierre Francois W, Jean-Philippe R, Yvon L, Eric R, Muller-Krebs S, Muller-Krebs S, Weber L, Tsobaneli J, Reiser J, Zeier M, Schwenger V, Tinel C, Samson M, Bonnotte B, Mousson C, Machcinska M, Machcinska M, Bocian K, Wyzgal M, Korczak-Kowalska G, Ju MK, Huh KH, Park KT, Kim SJ, Cho BH, Kim CD, So BJ, Leee S, Kang CM, Joo DJ, Kim YS, Bocian K, Zarzycki M, Sobich A, Korczak-Kowalska G, Matsuyama M, Hase T, Yoshimura R, Koshino K, Sakai K, Suzuki T, Nobori S, Ushigome H, Brikci-Nigassa L, Chargui J, Touraine JL, Yoshimura N, Cantaluppi V, Medica D, Figliolini F, Migliori M, Mannari C, Dellepiane S, Quercia AD, Randone O, Tamagnone M, Messina M, Manzione AM, Ranghino A, Biancone L, Segoloni GP, Camussi G, Turk TR, Zou X, Rauen U, De Groot H, Amann K, Kribben A, Eckardt KU, Bernhardt WM, Witzke O, Lidia G, Wouter C, Yvon L, Eric A, Yann LM, Guy T, Christian N, Marie E, Pierre M, Zineb A, Miriana D, Annick M, Marc A, Daniel A, Wornle M, Ribeiro A, Motamedi N, Grone HJ, Cohen CD, Schlondorff D, Schmid H, Teplan V, Banas M, Banas B, Steege A, Bergler T, Kruger B, Schnulle P, Yard B, Kramer BK, Hoger S, Xavier MP, Sampaio-Norton S, Gaiao S, Alves H, Oliveira G, Xavier MP, Sampaio-Norton S, Gaiao S, Alves H, Oliveira G, Xavier MP, Sampaio-Norton S, Gaiao S, Alves H, Oliveira G, Zaza G, Rascio F, Pontrelli P, Granata S, Rugiu C, Grandaliano G, Lupo A, Wohlfahrtova M, Wohlfahrtova M, Brabcova I, Balaz P, Janousek L, Lodererova A, Honsova E, Wohlfahrt P, Viklicky O, Grabner A, Grabner A, Kentrup D, Edemir B, Sirin Y, Pavenstadt H, Schober O, Schlatter E, Schafers M, Schnockel U, Reuter S, Rascio F, Pontrelli P, Accetturo M, Gigante M, Gigante M, Tataranni T, Zito A, Schena A, Schena FP, Stallone G, Gesualdo L, Grandaliano G, Maillard N, Masson I, Lena A, Manolie M, Eric A, Christophe M, Lassen CK, Keller AK, Moldrup U, Bibby BM, Jespersen B, Cvetkovic T, Velickovic Radovanovic R, Pavlovic R, Djordjevic V, Vlahovic P, Stefanovic N, Sladojevic N, Ignjatovic A, Rong S, Menne J, Haller H, Suszdak P, Tomczuk P, Gueler F, Nelli S, Sara D, Salma EK, Naoufal M, Tarik M, Mohamed Z, Guislaine M, Mohamed Gharbi B, Benyounes R, Lu X, Rong S, Shushakova N, Menne J, Kirsch T, Haller H, Gueler F, Bockmeyer CL, Bockmeyer CL, Ramackers W, Wittig J, Agustian PA, Klose J, Dammrich ME, Kreipe H, Brocker V, Winkler M, Becker JU, Agustian PA, Bockmeyer CL, Wittig J, Becker JU, Bockmeyer CL. Transplantation - basic. Nephrol Dial Transplant 2012. [DOI: 10.1093/ndt/gfs247] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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Edemir B, Jardzejewski M, Schlatter E. Lithium and glycogen synthase kinase‐3 inhibition induces lysosomal degradation of aquaporin‐2. FASEB J 2012. [DOI: 10.1096/fasebj.26.1_supplement.885.14] [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: 11/11/2022]
Affiliation(s)
- Bayram Edemir
- Internal Medicine D, Experimental NephrologyUniversity Hospital MünsterMünsterGermany
| | - Marc Jardzejewski
- Internal Medicine D, Experimental NephrologyUniversity Hospital MünsterMünsterGermany
| | - Eberhard Schlatter
- Internal Medicine D, Experimental NephrologyUniversity Hospital MünsterMünsterGermany
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Hirsch B, Brast S, Grabner A, Holle S, Guckel D, Schlatter E, Ciarimboli G. Molecular interaction of organic cation transporters with the tetraspanin CD63 modulates transporter trafficking and their trafficking‐associated regulation. FASEB J 2012. [DOI: 10.1096/fasebj.26.1_supplement.1152.16] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | - Sabine Brast
- Exp. NephrologieUniversitätsklinikum MünsterMünsterGermany
| | | | - Svenja Holle
- Exp. NephrologieUniversitätsklinikum MünsterMünsterGermany
| | - Denise Guckel
- Exp. NephrologieUniversitätsklinikum MünsterMünsterGermany
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Ciarimboli G, Lancaster CS, Schlatter E, Franke RM, Sprowl JA, Pavenstädt H, Massmann V, Guckel D, Mathijssen RHJ, Yang W, Pui CH, Relling MV, Herrmann E, Sparreboom A. Proximal tubular secretion of creatinine by organic cation transporter OCT2 in cancer patients. Clin Cancer Res 2012; 18:1101-8. [PMID: 22223530 DOI: 10.1158/1078-0432.ccr-11-2503] [Citation(s) in RCA: 109] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
PURPOSE Knowledge of transporters responsible for the renal secretion of creatinine is key to a proper interpretation of serum creatinine and/or creatinine clearance as markers of renal function in cancer patients receiving chemotherapeutic agents. EXPERIMENTAL DESIGN Creatinine transport was studied in transfected HEK293 cells in vitro and in wild-type mice and age-matched organic cation transporter 1 and 2-deficient [Oct1/2(-/-)] mice ex vivo and in vivo. Clinical pharmacogenetic and transport inhibition studies were done in two separate cohorts of cancer patients. RESULTS Compared with wild-type mice, creatinine clearance was significantly impaired in Oct1/2(-/-) mice. Furthermore, creatinine inhibited organic cation transport in freshly isolated proximal tubules from wild-type mice and humans, but not in those from Oct1/2(-/-) mice. In a genetic association analysis (n = 590), several polymorphisms around the OCT2/SLC22A2 gene locus, including rs2504954 (P = 0.000873), were significantly associated with age-adjusted creatinine levels. Furthermore, in cancer patients (n = 68), the OCT2 substrate cisplatin caused an acute elevation of serum creatinine (P = 0.0083), consistent with inhibition of an elimination pathway. CONCLUSIONS Collectively, this study shows that OCT2 plays a decisive role in the renal secretion of creatinine. This process can be inhibited by OCT2 substrates, which impair the usefulness of creatinine as a marker of renal function.
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Affiliation(s)
- Giuliano Ciarimboli
- Medizinische Klinik und Poliklinik D, Experimentelle Nephrologie, and Klinik und Poliklinik für Urologie, Universitätsklinikum Münster, Münster, Germany
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Brast S, Grabner A, Sucic S, Sitte HH, Hermann E, Pavenstädt H, Schlatter E, Ciarimboli G. The cysteines of the extracellular loop are crucial for trafficking of human organic cation transporter 2 to the plasma membrane and are involved in oligomerization. FASEB J 2011; 26:976-86. [PMID: 22085643 DOI: 10.1096/fj.11-180679] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Human organic cation transporter 2 (hOCT2) is involved in transport of many endogenous and exogenous organic cations, mainly in kidney and brain cells. Because the quaternary structure of transmembrane proteins plays an essential role for their cellular trafficking and function, we investigated whether hOCT2 forms oligomeric complexes, and if so, which part of the transporter is involved in the oligomerization. A yeast 2-hybrid mating-based split-ubiquitin system (mbSUS), fluorescence resonance energy transfer, Western blot analysis, cross-linking experiments, immunofluorescence, and uptake measurements of the fluorescent organic cation 4-(4-(dimethylamino)styryl)-N-methylpyridinium were applied to human embryonic kidney 293 (HEK293) cells transfected with hOCT2 and partly also to freshly isolated human proximal tubules. The role of cysteines for oligomerization and trafficking of the transporter to the plasma membranes was investigated in cysteine mutants of hOCT2. hOCT2 formed oligomers both in the HEK293 expression system and in native human kidneys. The cysteines of the large extracellular loop are important to enable correct folding, oligomeric assembly, and plasma membrane insertion of hOCT2. Mutation of the first and the last cysteines of the loop at positions 51 and 143 abolished oligomer formation. Thus, the cysteines of the extracellular loop are important for correct trafficking of the transporter to the plasma membrane and for its oligomerization.
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Affiliation(s)
- Sabine Brast
- Experimentelle Nephrologie, Medizinische Klinik und Poliklinik D, Domagkstrasse 3A, 48149 Münster, Germany
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Kentrup D, Reuter S, Schnöckel U, Grabner A, Edemir B, Pavenstädt H, Schober O, Schäfers M, Schlatter E, Büssemaker E. Hydroxyfasudil-mediated inhibition of ROCK1 and ROCK2 improves kidney function in rat renal acute ischemia-reperfusion injury. PLoS One 2011; 6:e26419. [PMID: 22031832 PMCID: PMC3198766 DOI: 10.1371/journal.pone.0026419] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2011] [Accepted: 09/26/2011] [Indexed: 11/18/2022] Open
Abstract
Renal ischemia-reperfusion (IR) injury (IRI) is a common and important trigger of acute renal injury (AKI). It is inevitably linked to transplantation. Involving both, the innate and the adaptive immune response, IRI causes subsequent sterile inflammation. Attraction to and transmigration of immune cells into the interstitium is associated with increased vascular permeability and loss of endothelial and tubular epithelial cell integrity. Considering the important role of cytoskeletal reorganization, mainly regulated by RhoGTPases, in the development of IRI we hypothesized that a preventive, selective inhibition of the Rho effector Rho-associated coiled coil containing protein kinase (ROCK) by hydroxyfasudil may improve renal IRI outcome. Using an IRI-based animal model of AKI in male Sprague Dawley rats, animals treated with hydroxyfasudil showed reduced proteinuria and polyuria as well as increased urine osmolarity when compared with sham-treated animals. In addition, renal perfusion (as assessed by 18F-fluoride Positron Emission Tomography (PET)), creatinine- and urea-clearances improved significantly. Moreover, endothelial leakage and renal inflammation was significantly reduced as determined by histology, 18F-fluordesoxyglucose-microautoradiography, Evans Blue, and real-time PCR analysis. We conclude from our study that ROCK-inhibition by hydroxyfasudil significantly improves kidney function in a rat model of acute renal IRI and is therefore a potential new therapeutic option in humans.
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Affiliation(s)
- Dominik Kentrup
- Department of Internal Medicine D, Experimental Nephrology, University of Münster, Münster, Germany
| | - Stefan Reuter
- Department of Internal Medicine D, Experimental Nephrology, University of Münster, Münster, Germany
| | - Uta Schnöckel
- Department of Nuclear Medicine, University of Münster, Münster, Germany
| | - Alexander Grabner
- Department of Internal Medicine D, Experimental Nephrology, University of Münster, Münster, Germany
| | - Bayram Edemir
- Department of Internal Medicine D, Experimental Nephrology, University of Münster, Münster, Germany
| | - Hermann Pavenstädt
- Department of Internal Medicine D, Experimental Nephrology, University of Münster, Münster, Germany
| | - Otmar Schober
- Department of Nuclear Medicine, University of Münster, Münster, Germany
| | - Michael Schäfers
- European Institute for Molecular Imaging, University of Münster, Münster, Germany
| | - Eberhard Schlatter
- Department of Internal Medicine D, Experimental Nephrology, University of Münster, Münster, Germany
| | - Eckhart Büssemaker
- Department of Internal Medicine D, Experimental Nephrology, University of Münster, Münster, Germany
- Dialysis Unit Hamm, Hamm, Germany
- * E-mail:
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Dobrivojević M, Sinđić A, Nikitović B, Edemir B, Schlatter E, Forssmann WG, Hirsch JR. Interaction between bradykinin and urodilatin - a possible mechanism of clinical relevance. BMC Pharmacol 2011. [PMCID: PMC3363214 DOI: 10.1186/1471-2210-11-s1-p21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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Rinschen MM, Klokkers J, Pavenstädt H, Schlatter E, Edemir B. Cyclosporine A decreases aquaporin‐2 expression in primary cultured inner medullary collecting duct cells. FASEB J 2011. [DOI: 10.1096/fasebj.25.1_supplement.1039.2] [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: 11/11/2022]
Affiliation(s)
| | - Jens Klokkers
- Med. Klinik und Poliklinik DUniversitätsklinikum MünsterMünsterGermany
| | | | | | - Bayram Edemir
- Med. Klinik und Poliklinik DUniversitätsklinikum MünsterMünsterGermany
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Edemir B, Pavenstädt H, Schlatter E, Weide T. Mechanisms of cell polarity and aquaporin sorting in the nephron. Pflugers Arch 2011; 461:607-21. [PMID: 21327781 DOI: 10.1007/s00424-011-0928-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2010] [Revised: 01/14/2011] [Accepted: 01/16/2011] [Indexed: 01/02/2023]
Abstract
The kidneys participate in whole-body homeostasis, regulating acid-base balance, electrolyte concentrations, extracellular fluid volume, and regulation of blood pressure. Many of the kidney's functions are accomplished by relatively simple mechanisms of filtration, reabsorption, and secretion, which take place in the nephron. The kidneys generate 140-180 l of primary urine per day, while reabsorbing a large percentage, allowing for only the excretion of approximately 2 l of urine. Within the nephron, the majority of the filtered water and solutes are reabsorbed. This is mainly facilitated by specialized transporters and channels which are localized at different segments of the nephron and asymmetrically localized within the polarized epithelial cells. The asymmetric localization of these transporters and channels is essential for the physiological tasks of the renal tissues. One family of these proteins are the water-permeable aquaporins which are selectively expressed in cells along the nephron and localized at different compartments. Here, we discuss potential molecular links between mechanisms involved in the establishment of cell polarity and the members of the aquaporin family. In the first part of this review, we will focus on aspects of apical cell polarity. In the second part, we will review the motifs identified so far that are involved in aquaporin sorting and point out potential molecular links.
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Affiliation(s)
- Bayram Edemir
- Medizinische Klinik und Poliklinik D, Experimentelle und Molekulare Nephrologie, Universität Münster, Germany.
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Schenk LK, Rinschen MM, Klokkers J, Kurian SM, Neugebauer U, Salomon DR, Pavenstaedt H, Schlatter E, Edemir B. Cyclosporin-A induced toxicity in rat renal collecting duct cells: interference with enhanced hypertonicity induced apoptosis. Cell Physiol Biochem 2011; 26:887-900. [PMID: 21220920 DOI: 10.1159/000323998] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/17/2010] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND/AIMS Rat renal inner medullary collecting duct (IMCD) cells are physiologically exposed to a wide range of ambient tonicity. To maintain their function upon changes in osmolality, IMCD cells induce expression of osmoprotective and antiapoptotic genes, mainly mediated by the transcription factor Tonicity Enhancer Binding Protein (TonEBP). Some drugs like Cyclosporin-A (CsA) are discussed to interfere with the activity of TonEBP and thereby mediate their nephrotoxic effects. The aim of our study was to further understand CsA toxicity during elevation of ambient osmolality. METHODS First we examined cytotoxicity of CsA in IMCD exposed to elevated tonicity. Employing microarray analysis of gene expression, real-time PCR and immunoassays, we scrutinized pathways contributing to this effect. RESULTS We show that in IMCD cells CsA but not FK506 increases apoptosis upon an increase in tonicity. This effect is independent of cellular TonEBP localization or activity and reactive oxygen species. Microarray studies revealed marked quantitative differences in gene expression. Functional analysis showed overrepresentation of genes associated with cell death in presence of CsA. This correlated with increased mRNA expression of genes associated with the death receptor pathway and detection of TNFα in culture medium of cells treated with CsA. CONCLUSION Our results show that CsA cytotoxicity is induced under elevated ambient osmolality and that death receptor signaling probably contributes to CsA cytotoxicity.
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Affiliation(s)
- Laura K Schenk
- Department of Internal Medicine D, Experimental Nephrology, University of Muenster, Muenster, Germany
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Ciarimboli G, Holle SK, Vollenbröcker B, Hagos Y, Reuter S, Burckhardt G, Bierer S, Herrmann E, Pavenstädt H, Rossi R, Kleta R, Schlatter E. New clues for nephrotoxicity induced by ifosfamide: preferential renal uptake via the human organic cation transporter 2. Mol Pharm 2010; 8:270-9. [PMID: 21077648 DOI: 10.1021/mp100329u] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Anticancer treatment with ifosfamide but not with its structural isomer cyclophosphamide is associated with development of renal Fanconi syndrome leading to diminished growth in children and bone problems in adults. Since both cytotoxics share the same principal metabolites, we investigated whether a specific renal uptake of ifosfamide is the basis for this differential effect. First we studied the interaction of these cytotoxics using cells transfected with organic anion or cation transporters and freshly isolated murine and human proximal tubules with appropriate tracers. Next we determined changes in membrane voltage in proximal tubular cells to understand their differentiated nephrotoxicity. Ifosfamide but not cyclophosphamide was significantly transported into cells expressing human organic cation transporter 2 (hOCT2) while both did not interact with organic anion transporters. This points toward a specific interaction of ifosfamide with hOCT2, which is the main OCT isoform in human kidney. In isolated human proximal tubules ifosfamide also interacted with organic cation transport. This interaction was also seen in isolated mouse proximal tubules; however, it was absent in tubules from OCT-deficient mice, illustrating the biological importance of this selective transport. Ifosfamide decreased the viability of cells expressing hOCT2, but not that of control cells. Coadministration of cimetidine, a known competitive substrate of hOCT2, completely prevented this ifosfamide-induced toxicity. Finally, ifosfamide but not cyclophosphamide depolarized proximal tubular cells. We propose that the nephrotoxicity of ifosfamide is due to its selective uptake by hOCT2 into renal proximal tubular cells, and that coadministration of cimetidine may be used to prevent ifosfamide-induced nephrotoxicity.
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Affiliation(s)
- Giuliano Ciarimboli
- Medizinische Klinik und Poliklinik D, Experimentelle Nephrologie, Universitätsklinikum Münster, Münster, Germany
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Reuter S, Schnöckel U, Edemir B, Schröter R, Kentrup D, Pavenstädt H, Schober O, Schlatter E, Gabriëls G, Schäfers M. Potential of noninvasive serial assessment of acute renal allograft rejection by 18F-FDG PET to monitor treatment efficiency. J Nucl Med 2010; 51:1644-52. [PMID: 20847180 DOI: 10.2967/jnumed.110.078550] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
UNLABELLED We propose (18)F-FDG PET as a method to monitor acute rejection of allogeneic renal transplants in a rat model. METHODS Allogeneically transplanted (aTX) rats (binephrectomized Lewis-brown Norway to Lewis) served as the renal transplant model. aTX rats treated with cyclosporine A (CSA) served as a therapy monitoring group. Healthy control rats, rats with acute CSA nephrotoxicity, rats with acute tubular necrosis, syngeneically transplanted (sTX) rats, and aTX rats treated with CSA since postoperative day 0 served as controls. After surgery, renal glucose metabolism was assessed in vivo serially up to postoperative day 7 by performing small-animal PET 3 h after intravenous injection of 30 MBq of (18)F-FDG. Mean radioactivity (cps/mm(3) of tissue) was measured and the percentage injected dose calculated. Results were confirmed by histologic, functional, and autoradiographic analysis. RESULTS Renal (18)F-FDG uptake was significantly elevated at postoperative day 4 in aTX rats, when compared with control, sTX, acute tubular necrosis, or CSA-treated rats (P < 0.05). In vivo (18)F-FDG uptake correlated with the results of autoradiography and with inflammatory infiltrates observed on histologic examination. Notably, (18)F-FDG PET assessed the response to therapy 48 h earlier than the time at which serum creatinine decreased and when histologic examination still showed signs of allograft rejection. In aTX rats, the CSA-susceptible graft infiltrate was dominated by activated cytotoxic T cells and monocytes/macrophages. CONCLUSION (18)F-FDG PET is an option to noninvasively assess early response to therapy in rat renal allograft rejection.
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Affiliation(s)
- Stefan Reuter
- Department of Medicine D, Experimental Nephrology, University of Münster, Münster, Germany.
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Edemir B, Klokkers J, Pavenstädt H, Schlatter E. Gene expression profiling and immune fluorescence implicate cellular redifferentiation induced by hypertonicity in primary cultured IMCD cells. FASEB J 2010. [DOI: 10.1096/fasebj.24.1_supplement.817.1] [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: 11/11/2022]
Affiliation(s)
- Bayram Edemir
- Department of Internal Medicine DUniversity of MünsterMünsterGermany
| | - Jens Klokkers
- Department of Internal Medicine DUniversity of MünsterMünsterGermany
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Reuter S, Reiermann S, Wörner R, Schröter R, Edemir B, Buck F, Henning S, Peter-Katalinic J, Vollenbröker B, Amann K, Pavenstädt H, Schlatter E, Gabriëls G. IF/TA-related metabolic changes--proteome analysis of rat renal allografts. Nephrol Dial Transplant 2010; 25:2492-501. [PMID: 20176611 DOI: 10.1093/ndt/gfq043] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Chronic allograft nephropathy, now more specifically termed interstitial fibrosis and tubular atrophy without evidence of any specific aetiology (IF/TA), is still an important cause of late graft loss. There is no effective therapy for IF/TA, in part due to the disease's multifactorial nature and its incompletely understood pathogenesis. METHODS We used a differential in-gel electrophoresis and mass spectrometry technique to study IF/TA in a renal transplantation model. Dark Agouti (DA) kidneys were allogeneically transplanted to Wistar-Furth (DA-WF, aTX) rats. Syngeneic grafts (DA-DA, sTX) served as controls. Nine weeks after transplantation, blood pressure, renal function and electrolytes were studied, in addition to real-time PCR, western blot analysis, histology and immunohistochemistry. RESULTS In contrast to sTX, the aTX developed IF/TA-dependent renal damage. Ten differentially regulated proteins were identified by 2D gel analysis and mass spectrometry, whereupon five proteins are mainly related to oxidative stress (aldo-keto reductase, peroxiredoxin-1, NAD(+)-dependent isocitrate dehydrogenase, iron-responsive element-binding protein-1 and serum albumin), two participate in cytoskeleton organization (l-plastin and ezrin) and three are assigned to metabolic functions (creatine kinase, ornithine aminotransferase and fructose-1,6-bisphosphatase). CONCLUSION The proteins related to IF/TA and involved in oxidative stress, cytoskeleton organization and metabolic functions may correspond with novel therapeutic targets.
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Affiliation(s)
- Stefan Reuter
- Department of Medicine D, University of Münster, Münster, Germany.
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Ciarimboli G, Deuster D, Knief A, Sperling M, Holtkamp M, Edemir B, Pavenstädt H, Lanvers-Kaminsky C, am Zehnhoff-Dinnesen A, Schinkel AH, Koepsell H, Jürgens H, Schlatter E. Organic cation transporter 2 mediates cisplatin-induced oto- and nephrotoxicity and is a target for protective interventions. Am J Pathol 2010; 176:1169-80. [PMID: 20110413 DOI: 10.2353/ajpath.2010.090610] [Citation(s) in RCA: 313] [Impact Index Per Article: 22.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The use of the effective antineoplastic agent cisplatin is limited by its serious side effects, such as oto- and nephrotoxicity. Ototoxicity is a problem of special importance in children, because deafness hampers their language and psychosocial development. Recently, organic cation transporters (OCTs) were identified in vitro as cellular uptake mechanisms for cisplatin. In the present study, we investigated in an in vivo model the role of OCTs in the development of cisplatin oto- and nephrotoxicity. The functional effects of cisplatin treatment on kidney (24 hours excretion of glucose, water, and protein) and hearing (auditory brainstem response) were studied in wild-type and OCT1/2 double-knockout (KO) mice. No sign of ototoxicity and only mild nephrotoxicity were observed after cisplatin treatment of knockout mice. Comedication of wild-type mice with cisplatin and the organic cation cimetidine protected from ototoxicity and partly from nephrotoxicity. For the first time we showed that OCT2 is expressed in hair cells of the cochlea. Furthermore, cisplatin-sensitive cell lines from pediatric tumors showed no expression of mRNA for OCTs, indicating the feasibility of therapeutic approaches aimed to reduce cisplatin toxicities by competing OCT2-mediated cisplatin uptake in renal proximal tubular and cochlear hair cells. These findings are very important to establish chemotherapeutical protocols aimed to maximize the antineoplastic effect of cisplatin while reducing the risk of toxicities.
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Affiliation(s)
- Giuliano Ciarimboli
- Medizinische Klinik und Poliklinik D, Experimentelle Nephrologie, Universitätsklinikum Münster, Domagkstr. 3a, 48149 Münster, Germany.
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Klokkers J, Langehanenberg P, Kemper B, Kosmeier S, von Bally G, Riethmüller C, Wunder F, Sindic A, Pavenstädt H, Schlatter E, Edemir B. Atrial natriuretic peptide and nitric oxide signaling antagonizes vasopressin-mediated water permeability in inner medullary collecting duct cells. Am J Physiol Renal Physiol 2009; 297:F693-703. [PMID: 19570884 DOI: 10.1152/ajprenal.00136.2009] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
AVP and atrial natriuretic peptide (ANP) have opposite effects in the kidney. AVP induces antidiuresis by insertion of aquaporin-2 (AQP2) water channels into the plasma membrane of collecting duct principal cells. ANP acts as a diuretic factor. An ANP- and nitric oxide (NO)/soluble guanylate cyclase (sGC)-induced insertion of AQP2 into the plasma membrane is reported from different models. However, functional data on the insertion of AQP2 is missing. We used primary cultured inner medullary collecting duct (IMCD) cells and digital holographic microscopy, calcein-quenching measurements, and immunofluorescence and Western blotting to analyze the effects of ANP and NO donors on AQP2 phosphorylation, membrane expression, and water permeability. While AVP led to acceleration in osmotically induced swelling, ANP had no effect. However, in AVP-pretreated cells ANP significantly decreased the kinetics of cell swelling. This effect was mimicked by 8-bromo-cGMP and blunted by PKG inhibition. Stimulation of the NO/sGC pathway or direct activation of sGC with BAY 58-2667 had similar effects to ANP. In cells treated with AVP, AQP2 was predominantly localized in the plasma membrane, and after additional incubation with ANP AQP2 was mostly localized in the cytosol, indicating an increased retrieval of AQP2 from the plasma membrane by ANP. Western blot analysis showed that ANP was able to reduce AVP-induced phosphorylation of AQP2 at position S256. In conclusion, we show that the diuretic action of ANP or NO in the IMCD involves a decreased localization of AQP2 in the plasma membrane which is mediated by cGMP and PKG.
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Affiliation(s)
- Jens Klokkers
- Medizinische Klinik und Poliklinik D, Experimentelle Nephrologie, Universitätsklinikum Münster, Münster, Germany
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Reuter S, Schnöckel U, Schröter R, Schober O, Pavenstädt H, Schäfers M, Gabriëls G, Schlatter E. Non-invasive imaging of acute renal allograft rejection in rats using small animal F-FDG-PET. PLoS One 2009; 4:e5296. [PMID: 19390685 PMCID: PMC2669171 DOI: 10.1371/journal.pone.0005296] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2008] [Accepted: 03/30/2009] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND At present, renal grafts are the most common solid organ transplants world-wide. Given the importance of renal transplantation and the limitation of available donor kidneys, detailed analysis of factors that affect transplant survival are important. Despite the introduction of new and effective immunosuppressive drugs, acute cellular graft rejection (AR) is still a major risk for graft survival. Nowadays, AR can only be definitively by renal biopsy. However, biopsies carry a risk of renal transplant injury and loss. Most important, they can not be performed in patients taking anticoagulant drugs. METHODOLOGY/PRINCIPAL FINDINGS We present a non-invasive, entirely image-based method to assess AR in an allogeneic rat renal transplantation model using small animal positron emission tomography (PET) and (18)F-fluorodeoxyglucose (FDG). 3 h after i.v. injection of 30 MBq FDG into adult uni-nephrectomized, allogeneically transplanted rats, tissue radioactivity of renal parenchyma was assessed in vivo by a small animal PET-scanner (post operative day (POD) 1,2,4, and 7) and post mortem dissection. The mean radioactivity (cps/mm(3) tissue) as well as the percent injected dose (%ID) was compared between graft and native reference kidney. Results were confirmed by histological and autoradiographic analysis. Healthy rats, rats with acute CSA nephrotoxicity, with acute tubular necrosis, and syngeneically transplanted rats served as controls. FDG-uptake was significantly elevated only in allogeneic grafts from POD 1 on when compared to the native kidney (%ID graft POD 1: 0.54+/-0.06; POD 2: 0.58+/-0.12; POD 4: 0.81+/-0.06; POD 7: 0.77+/-0.1; CTR: 0.22+/-0.01, n = 3-28). Renal FDG-uptake in vivo correlated with the results obtained by micro-autoradiography and the degree of inflammatory infiltrates observed in histology. CONCLUSIONS/SIGNIFICANCE We propose that graft FDG-PET imaging is a new option to non-invasively, specifically, early detect, and follow-up acute renal rejection. This method is potentially useful to improve post-transplant rejection monitoring.
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Affiliation(s)
- Stefan Reuter
- Medizinische Klinik und Poliklinik D, Experimentelle Nephrologie, Universitätsklinikum Münster, Münster, Germany.
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Wilde S, Schlatter E, Koepsell H, Edemir B, Reuter S, Pavenstädt H, Neugebauer U, Schröter R, Brast S, Ciarimboli G. Calmodulin-associated post-translational regulation of rat organic cation transporter 2 in the kidney is gender dependent. Cell Mol Life Sci 2009; 66:1729-40. [DOI: 10.1007/s00018-009-9145-z] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Hsu HH, Hoffmann S, Endlich N, Velic A, Schwab A, Weide T, Schlatter E, Pavenstädt H. Mechanisms of angiotensin II signaling on cytoskeleton of podocytes. J Mol Med (Berl) 2008; 86:1379-94. [PMID: 18773185 DOI: 10.1007/s00109-008-0399-y] [Citation(s) in RCA: 121] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2007] [Revised: 07/12/2008] [Accepted: 08/01/2008] [Indexed: 01/16/2023]
Abstract
Podocytes are significant in establishing the glomerular filtration barrier. Sustained rennin-angiotensin system (RAS) activation is crucial in the pathogenesis of podocyte injury and causes proteinuria. This study demonstrates that angiotensin II (Ang II) caused a reactive oxygen species (ROS)-dependent rearrangement of cortical F-actin and a migratory phenotype switch in cultured mouse podocytes with stable Ang II type 1 receptor (AT1R) expression. Activated small GTPase Rac-1 and phosphorylated ezrin/radixin/moesin (ERM) proteins provoked Ang II-induced F-actin cytoskeletal remodeling. This work also shows increased expression of Rac-1 and phosphorylated ERM proteins in cultured podocytes, and in glomeruli of podocyte-specific AT1R transgenic rats (Neph-hAT1 TGRs). The free radical scavenger DMTU eliminated Ang II-induced cell migration, ERM protein phosphorylation and cortical F-actin remodeling, indicating that ROS mediates the influence of Rac-1 on podocyte AT1R signaling. Heparin, a potent G-coupled protein kinase 2 inhibitor, was found to abolish ERM protein phosphorylation and cortical F-actin ring formation in Ang II-treated podocytes, indicating that phosphorylated ERM proteins are the cytoskeletal effector in AT1R signaling. Moreover, Ang II stimulation triggered down-regulation of alpha actinin-4 and reduced focal adhesion expression in podocytes. Signaling inhibitor assay of Ang II-treated podocytes reveals that Rac-1, RhoA, and F-actin reorganization were involved in expressional regulation of alpha actinin-4 in AT1R signaling. With persistent RAS activation, the Ang II-induced phenotype shifts from being dynamically stable to adaptively migratory, which may eventually exhaust podocytes with a high actin cytoskeletal turnover, causing podocyte depletion and focal segmental glomerulosclerosis.
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Affiliation(s)
- Hsiang-Hao Hsu
- Department of Medicine D, Division of General Internal Medicine and Nephrology, University Hospital Muenster, Albert-Schweitzer-Str. 33, 48149 Muenster, Germany
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Schnöckel U, Reuter S, Stegger L, Schlatter E, Schäfers KP, Hermann S, Schober O, Gabriëls G, Schäfers M. Dynamic 18F-fluoride small animal PET to noninvasively assess renal function in rats. Eur J Nucl Med Mol Imaging 2008; 35:2267-74. [PMID: 18622612 DOI: 10.1007/s00259-008-0878-y] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2007] [Accepted: 06/23/2008] [Indexed: 12/23/2022]
Abstract
PURPOSE Renal function can be quantified by both laboratory and scintigraphic methods. In the case of small animal diagnostics, scintigraphic image-based methods are ideal since they can assess split renal function, work noninvasively, and can be repeated. The aim of this study is to validate a (18)F-PET-based method to quantify renal function in rats. MATERIALS AND METHODS Fluoride clearance was calculated from a dynamic whole body listmode acquisition of 60 min length in a small animal PET scanner following an i.v. injection of 15 MBq (18)F-fluoride. Volumes of interest (VOIs) were placed in the left ventricle and the bladder as well as traced around the kidney contours. The respective time-activity curves (TAC) were calculated. The renal (18)F-clearance was calculated by the ratio of the total renal excreted activity (bladder VOI) and the integral of the blood TAC. PET-derived renal function was validated by intraindividual measurements of creatinine clearance (n = 23), urea clearance (n = 23), and tubular excretion rate (TER-MAG3). The split renal function was derived from the injection of the clinically available radionuclide (99m)Tc-mercaptotriglycine by blood sampling and planar renography (n = 8). RESULTS In all animals studied, PET revealed high-quality TACs. PET-derived renal fluoride clearance was linearly correlated with intraindividual laboratory measures (PET vs. creatinine: r = 0.78; PET vs. urea: r = 0.73; PET vs. TER-MAG3: r = 0.73). Split function was comparable ((18)F-PET vs. MAG3-renography: r = 0.98). PET-derived measures were highly reproducible. CONCLUSIONS (18)F-PET is able to noninvasively assess renal function in rats and provides a significant potential for serial studies in different experimental scenarios.
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Affiliation(s)
- Uta Schnöckel
- Klinik und Poliklinik für Nuklearmedizin, 48149 Münster, Germany.
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Reuter S, Velic A, Edemir B, Schröter R, Pavenstädt H, Gabriëls G, Bleich M, Schlatter E. Protective role of NHE-3 inhibition in rat renal transplantation undergoing acute rejection. Pflugers Arch 2008; 456:1075-84. [PMID: 18335234 DOI: 10.1007/s00424-008-0484-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2007] [Revised: 02/11/2008] [Accepted: 02/23/2008] [Indexed: 12/26/2022]
Abstract
Acute rejection in renal transplantation disturbs solute and volume maintenance in humans accompanied by delayed graft function and poor prognosis. We recently reported that decreased expression and function of Na+/H+ exchanger type 3 (NHE-3) in proximal tubules and epithelial Na+ channels and aquaporin 2 in collecting ducts are major mechanisms involved in Na+ and water imbalances shortly after transplantation in rat undergoing acute rejection. We performed kidney transplantations in rats with bilaterally nephrectomized recipients with acute rejection and, in addition, systemically administered a specific inhibitor of NHE-3 (NHE-I). NHE inhibition in acute renal failure was shown to improve tubular function and recovery. The aim of this therapy was to reduce energy consumption of the graft and preserve NHE-3 function. Imbalances in electrolyte excretion declined in NHE-I-treated animals and NHE-3 activity was preserved. Observed NHE-I-dependent changes in electrolyte excretion, polyuria, and reduced protein reabsorption in the acute postoperative phase are predictors of favorable graft outcome in humans.
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Affiliation(s)
- Stefan Reuter
- Medizinische Klinik und Poliklinik D, Experimentelle Nephrologie, Universitätsklinikum Münster, Münster, Germany
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