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Wagner MC, Sandoval RM, Yadav SPS, Campos SB, Rhodes GJ, Phillips CL, Molitoris BA. Lrpap1 (RAP) Inhibits Proximal Tubule Clathrin Mediated and Clathrin Independent Endocytosis, Ameliorating Renal Aminoglycoside Nephrotoxicity. KIDNEY360 2023; 4:591-605. [PMID: 36848531 PMCID: PMC10278819 DOI: 10.34067/kid.0000000000000094] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Accepted: 01/31/2023] [Indexed: 03/01/2023]
Abstract
Key Points Proximal tubule endocytosis of toxins often leads to nephrotoxicity. Inhibition of endocytosis with receptor-associated protein may serve as a clinical approach to reduce or eliminate kidney damage from a potential nephrotoxin. Background Proximal tubules (PTs) are exposed to many exogenous and endogenous nephrotoxins that pass through the glomerular filter. This includes many small molecules, such as aminoglycoside and myeloma light chains. These filtered molecules are rapidly endocytosed by the PTs and lead to nephrotoxicity. Methods To investigate whether inhibition of PT uptake of filtered toxins can reduce toxicity, we evaluated the ability of Lrpap1 or receptor-associated protein (RAP) to prevent PT endocytosis. Munich Wistar Frömter rats were used since both glomerular filtration and PT uptake can be visualized and quantified. The injury model chosen was the well-established gentamicin-induced toxicity, which leads to significant reductions in GFR and serum creatinine increases. CKD was induced with a right uninephrectomy and left 40-minute pedicle clamp. Rats had 8 weeks to recover and to stabilize GFR and proteinuria. Multiphoton microscopy was used to evaluate endocytosis in vivo and serum creatinine, and 24-hour creatinine clearances were used to evaluate kidney functional changes. Results Studies showed that preadministration of RAP significantly inhibited both albumin and dextran endocytosis in outer cortical PTs. Importantly, this inhibition was found to be rapidly reversible with time. RAP was also found to be an excellent inhibitor of PT gentamicin endocytosis. Finally, gentamicin administration for 6 days resulted in significant elevation of serum creatinine in vehicle-treated rats, but not in those receiving daily infusion of RAP before gentamicin. Conclusions This study provides a model for the potential use of RAP to prevent, in a reversible manner, PT endocytosis of potential nephrotoxins, thus protecting the kidney from damage.
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Affiliation(s)
- Mark C Wagner
- Indiana Center for Biological Microscopy, Indiana University School of Medicine, Indianapolis, Indiana
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Sardella D, Kristensen AM, Bordoni L, Kidmose H, Shahrokhtash A, Sutherland DS, Frische S, Schiessl IM. Serial intravital 2-photon microscopy and analysis of the kidney using upright microscopes. Front Physiol 2023; 14:1176409. [PMID: 37168225 PMCID: PMC10164931 DOI: 10.3389/fphys.2023.1176409] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Accepted: 04/03/2023] [Indexed: 05/13/2023] Open
Abstract
Serial intravital 2-photon microscopy of the kidney and other abdominal organs is a powerful technique to assess tissue function and structure simultaneously and over time. Thus, serial intravital microscopy can capture dynamic tissue changes during health and disease and holds great potential to characterize (patho-) physiological processes with subcellular resolution. However, successful image acquisition and analysis require significant expertise and impose multiple potential challenges. Abdominal organs are rhythmically displaced by breathing movements which hamper high-resolution imaging. Traditionally, kidney intravital imaging is performed on inverted microscopes where breathing movements are partly compensated by the weight of the animal pressing down. Here, we present a custom and easy-to-implement setup for intravital imaging of the kidney and other abdominal organs on upright microscopes. Furthermore, we provide image processing protocols and a new plugin for the free image analysis software FIJI to process multichannel fluorescence microscopy data. The proposed image processing pipelines cover multiple image denoising algorithms, sample drift correction using 2D registration, and alignment of serial imaging data collected over several weeks using landmark-based 3D registration. The provided tools aim to lower the barrier of entry to intravital microscopy of the kidney and are readily applicable by biomedical practitioners.
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Affiliation(s)
- Donato Sardella
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | | | - Luca Bordoni
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - Hanne Kidmose
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - Ali Shahrokhtash
- Interdisciplinary Nanoscience Center, Aarhus University, Aarhus, Denmark
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Comper WD, Vuchkova J, McCarthy KJ. New insights into proteinuria/albuminuria. Front Physiol 2022; 13:991756. [PMID: 36225307 PMCID: PMC9548894 DOI: 10.3389/fphys.2022.991756] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Accepted: 08/29/2022] [Indexed: 11/13/2022] Open
Abstract
The fractional clearance of proteins as measured in healthy human subjects increases 10,000–100,000- fold when studied in nephrotic patients. This remarkable increase cannot be accounted for by extracellular biophysical mechanisms centered at the glomerular filtration barrier. Rather, it is the nephron and its combination of filtration and cellular uptake that can provide a plausible explanation of these fractional clearance changes. The nephron has two regions that critically determine the level proteinuria/albuminuria. Glomerular filtration of plasma proteins is primarily a size selective event that is basically unchanged in acquired and genetic kidney disease. The glomerular concepts of ‘charge selectivity’ and of ‘large pores’, previously used to explain proteinuria, are now recognized to be flawed and non-existent. Filtered proteins then encounter downstream two protein receptors of the Park and Maack type associated with the proximal tubular cell. The high capacity receptor is thought to retrieve the majority of filtered proteins and return them to the blood supply. Inhibition/saturation of this pathway in kidney disease may create the nephrotic condition and hypoproteinemia/hypoalbuminemia. Inhibitors of this pathway (possibly podocyte derived) are still to be identified. A relatively small proportion of the filtered protein is directed towards a high affinity, low capacity receptor that guides the protein to undergo lysosomal degradation. Proteinuria in normoproteinemic states is derived by inhibition of this pathway, such as in diabetes. The combination of glomerular sieving, and the degradation and retrieval pathways can quantitatively account for the changes in fractional clearance of proteins in the nephrotic condition. Finally, the general retrieval of filtered protein by the proximal tubular cell focuses on the teleological importance of this cell as this retrieval represents the third pillar of retrieval that this cell participates in (it also retrieves water and salt).
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Affiliation(s)
- Wayne D. Comper
- Salaqua Diagnostics Inc, New York, NY, United States
- *Correspondence: Wayne D. Comper,
| | | | - Kevin J. McCarthy
- Department of Cellular Biology and Anatomy, LSU Health Sciences Center, Shreveport, LA, United States
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Rinschen MM, Palygin O, El-Meanawy A, Domingo-Almenara X, Palermo A, Dissanayake LV, Golosova D, Schafroth MA, Guijas C, Demir F, Jaegers J, Gliozzi ML, Xue J, Hoehne M, Benzing T, Kok BP, Saez E, Bleich M, Himmerkus N, Weisz OA, Cravatt BF, Krüger M, Benton HP, Siuzdak G, Staruschenko A. Accelerated lysine metabolism conveys kidney protection in salt-sensitive hypertension. Nat Commun 2022; 13:4099. [PMID: 35835746 PMCID: PMC9283537 DOI: 10.1038/s41467-022-31670-0] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Accepted: 06/27/2022] [Indexed: 01/07/2023] Open
Abstract
Hypertension and kidney disease have been repeatedly associated with genomic variants and alterations of lysine metabolism. Here, we combined stable isotope labeling with untargeted metabolomics to investigate lysine's metabolic fate in vivo. Dietary 13C6 labeled lysine was tracked to lysine metabolites across various organs. Globally, lysine reacts rapidly with molecules of the central carbon metabolism, but incorporates slowly into proteins and acylcarnitines. Lysine metabolism is accelerated in a rat model of hypertension and kidney damage, chiefly through N-alpha-mediated degradation. Lysine administration diminished development of hypertension and kidney injury. Protective mechanisms include diuresis, further acceleration of lysine conjugate formation, and inhibition of tubular albumin uptake. Lysine also conjugates with malonyl-CoA to form a novel metabolite Nε-malonyl-lysine to deplete malonyl-CoA from fatty acid synthesis. Through conjugate formation and excretion as fructoselysine, saccharopine, and Nε-acetyllysine, lysine lead to depletion of central carbon metabolites from the organism and kidney. Consistently, lysine administration to patients at risk for hypertension and kidney disease inhibited tubular albumin uptake, increased lysine conjugate formation, and reduced tricarboxylic acid (TCA) cycle metabolites, compared to kidney-healthy volunteers. In conclusion, lysine isotope tracing mapped an accelerated metabolism in hypertension, and lysine administration could protect kidneys in hypertensive kidney disease.
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Affiliation(s)
- Markus M Rinschen
- Scripps Center for Metabolomics, Scripps Research, La Jolla, CA, 92037, USA.
- Department of Biomedicine, Aarhus University, Aarhus, Denmark.
- III. Medical Clinic, University Hospital Hamburg Eppendorf, Hamburg, Germany.
- AIAS, Aarhus Institute of Advanced Studies (AIAS), Aarhus University, Aarhus, Denmark.
| | - Oleg Palygin
- Division of Nephrology, Department of Medicine, Medical University of South Carolina, Charleston, SC, 29425, USA
| | - Ashraf El-Meanawy
- Division of Nephrology, Department of Medicine, Medical College of Wisconsin, Milwaukee, WI, 53226, USA
| | - Xavier Domingo-Almenara
- Scripps Center for Metabolomics, Scripps Research, La Jolla, CA, 92037, USA
- Omics Sciences Unit, EURECAT, Technology Centre of Catalonia, Reus, Catalonia, Spain
| | - Amelia Palermo
- Scripps Center for Metabolomics, Scripps Research, La Jolla, CA, 92037, USA
- Department of Molecular and Medical Pharmacology, David Geffen School of Medicine, University of California, Los Angeles, USA
| | - Lashodya V Dissanayake
- Department of Molecular Pharmacology and Physiology, University of South Florida, Tampa, FL, 33602, USA
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI, 53226, USA
| | - Daria Golosova
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI, 53226, USA
| | | | - Carlos Guijas
- Scripps Center for Metabolomics, Scripps Research, La Jolla, CA, 92037, USA
| | - Fatih Demir
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | | | - Megan L Gliozzi
- Renal Electrolyte Division, Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA, 15261, USA
| | - Jingchuan Xue
- Scripps Center for Metabolomics, Scripps Research, La Jolla, CA, 92037, USA
| | - Martin Hoehne
- Center for Molecular Medicine Cologne, Cologne, Germany
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases, Cologne, Germany
- Department II of Internal Medicine, University Hospital of Cologne, Cologne, Germany
| | - Thomas Benzing
- Center for Molecular Medicine Cologne, Cologne, Germany
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases, Cologne, Germany
- Department II of Internal Medicine, University Hospital of Cologne, Cologne, Germany
| | - Bernard P Kok
- Department of Molecular Medicine, Scripps Research, La Jolla, CA, 92037, USA
| | - Enrique Saez
- Department of Molecular Medicine, Scripps Research, La Jolla, CA, 92037, USA
| | - Markus Bleich
- Institute of Physiology, University Kiel, Kiel, Germany
| | | | - Ora A Weisz
- Renal Electrolyte Division, Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA, 15261, USA
| | | | - Marcus Krüger
- Center for Molecular Medicine Cologne, Cologne, Germany
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases, Cologne, Germany
| | - H Paul Benton
- Scripps Center for Metabolomics, Scripps Research, La Jolla, CA, 92037, USA
| | - Gary Siuzdak
- Scripps Center for Metabolomics, Scripps Research, La Jolla, CA, 92037, USA.
| | - Alexander Staruschenko
- Department of Molecular Pharmacology and Physiology, University of South Florida, Tampa, FL, 33602, USA.
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI, 53226, USA.
- James A. Haley Veterans' Hospital, Tampa, FL, 33612, USA.
- Hypertension and Kidney Research Center, University of South Florida, Tampa, FL, 33602, USA.
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Circadian rhythm of the intrarenal renin-angiotensin system is caused by glomerular filtration of liver-derived angiotensinogen depending on glomerular capillary pressure in adriamycin nephropathy rats. Hypertens Res 2021; 44:618-627. [PMID: 33558668 DOI: 10.1038/s41440-021-00620-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Revised: 12/04/2020] [Accepted: 12/18/2020] [Indexed: 01/31/2023]
Abstract
Circadian fluctuation disorder of the intrarenal renin-angiotensin system (RAS) causes that of blood pressure (BP) and renal damage. In renal damage with an impaired glomerular filtration barrier, liver-derived angiotensinogen (AGT) filtered through damaged glomeruli regulates intrarenal RAS activity. Furthermore, glomerular permeability is more strongly affected by glomerular hypertension than by systemic hypertension. Thus, we aimed to clarify whether the circadian rhythm of intrarenal RAS activity is influenced by AGT filtered through damaged glomeruli due to glomerular capillary pressure. Rats with adriamycin nephropathy and an impaired glomerular filtration barrier were compared with control rats. In adriamycin nephropathy rats, olmesartan medoxomil (an angiotensin II type 1 receptor blocker) or hydralazine (a vasodilator) was administered, and the levels of intrarenal RAS components in the active and rest phases were evaluated. Moreover, the diameter ratio of afferent to efferent arterioles (A/E ratio), an indicator of glomerular capillary pressure, and the glomerular sieving coefficient (GSC) based on multiphoton microscopy in vivo imaging, which reflects glomerular permeability, were determined. Mild renal dysfunction was induced, and the systemic BP increased, resulting in increased A/E ratios in the adriamycin nephropathy rats compared with the control rats. Fluctuations in intrarenal RAS activity occurred in parallel with circadian fluctuations in glomerular capillary pressure, which disappeared with olmesartan treatment and were maintained with hydralazine treatment. Furthermore, the GSCs for AGT also showed similar changes. In conclusion, intrarenal RAS activity is influenced by the filtration of liver-derived AGT from damaged glomeruli due to circadian fluctuation disorder of the glomerular capillary pressure.
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