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Kurpad AV, Pasanna RM, Hegde SG, Patil M, Mukhopadhyay A, Sachdev HS, Bhat KG, Sivadas A, Devi S. Bioavailability and daily requirement of vitamin B 12 in adult humans: an observational study of its colonic absorption and daily excretion as measured by [ 13C]-cyanocobalamin kinetics. Am J Clin Nutr 2023; 118:1214-1223. [PMID: 38044024 DOI: 10.1016/j.ajcnut.2023.08.020] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2023] [Revised: 08/28/2023] [Accepted: 08/30/2023] [Indexed: 12/05/2023] Open
Abstract
BACKGROUND Clinical and biochemical vitamin B12 (B12) deficiency is lower than anticipated in vegetarians. Extraileal absorption, such as from the colon, as well as reduced daily excretion, may be adaptive mechanisms to maintain B12 homeostasis with marginal intakes. OBJECTIVE To measure the absorption of B12 from the small and large intestine, and its daily rate of excretion from the body, using a [13C]-cyanocobalamin tracer. METHODS Oral B12 bioavailability was measured over 12 h after administration of [13C]-cyanocobalamin tracer (2.5 μg) in normal participants. The colonic B12 bioavailability was evaluated by direct instillation of [13C]-cyanocobalamin (5 μg) into the ascending colon. Bioavailability was calculated from 2-compartmental modeling of the tracer appearance in plasma. The excretion rate of B12 was measured from [13C]-cyanocobalamin elimination from the body over 4 wk after oral dosing (5 μg). RESULTS The oral B12 bioavailability (n = 11) was 63% ± 10% measured over 12 h. A late absorption peak, accounting for 12% of the absorption, was observed after an average lag time of 8.7 h from dosing. The colonic B12 bioavailability (n = 10) was 7% ± 5% over 4 h. The daily B12 excretion rate (n = 4) was 0.7 ± 0.2 μg/d. The minimum daily requirement of B12 in these participants was derived at 1 μg /d. CONCLUSIONS B12 is absorbed in the human colon. This observation confirms the potential contribution of the colon in daily B12 nutriture, and along with a possible lower requirement, could explain the absence of clinical deficiency in populations with marginal B12 intakes. TRIAL REGISTRATION NUMBER This study was registered in Clinical Trials Registry of India (CTRI) with the registration number CTRI/2018/04/012957, available from https://ctri.nic.in/Clinicaltrials/showallp.php?mid1=49319&EncHid=&userName=029108.
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Affiliation(s)
- Anura V Kurpad
- Department of Physiology, St. John's Medical College, Bengaluru, India.
| | - Roshni M Pasanna
- Division of Nutrition, St. John's Research Institute, Bengaluru, India
| | - Shalini G Hegde
- Department of Paediatric Surgery, St. John's Medical College, Bengaluru, India
| | - Mallikarjun Patil
- Department of Gastroenterology, St. John's Medical College, Bengaluru, India
| | | | - Harshpal S Sachdev
- Department of Paediatrics, Sitaram Bhartia Institute of Science and Research, New Delhi, India
| | - Kishor G Bhat
- Division of Nutrition, St. John's Research Institute, Bengaluru, India
| | - Ambily Sivadas
- Division of Nutrition, St. John's Research Institute, Bengaluru, India
| | - Sarita Devi
- Division of Nutrition, St. John's Research Institute, Bengaluru, India.
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Seliverstova EV, Prutskova NP. Renal protein reabsorption impairment related to a myxosporean infection in the grass frog (Rana temporaria L.). Parasitol Res 2023; 122:1303-1316. [PMID: 37012507 DOI: 10.1007/s00436-023-07830-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Accepted: 03/24/2023] [Indexed: 04/05/2023]
Abstract
A morphophysiological study of tubular reabsorption and mechanisms of protein endocytosis in the kidney of frogs (Rana temporaria L.) during parasitic infection was carried out. Pseudoplasmodia and spores of myxosporidia, beforehand assigned to the genus Sphaerospora, were detected in Bowman's capsules and in the lumen of individual renal tubules by light and electron microscopy. Remarkable morphological alteration and any signs of pathology in kidney tissue related to this myxosporean infection have not been noted. At the same time, significant changes in protein reabsorption and distribution of molecular markers of endocytosis in the proximal tubule (PT) cells in infected animals were detected by immunofluorescence confocal microscopy. In lysozyme injection experiments, the endocytosed protein and megalin expression in the infected PTs were not revealed. Tubular expression of cubilin and clathrin decreased, but endosomal recycling marker Rab11 increased or remained unchanged. Thus, myxosporean infection resulted in the alterations in lysozyme uptake and expression of the main molecular determinants of endocytosis. The inhibition of receptor-mediated clathrin-dependent protein endocytosis in amphibian kidneys due to myxosporidiosis was shown for the first time. Established impairment of the endocytic process is a clear marker of tubular cell dysfunction that can be used to assess the functioning of amphibian kidneys during adaptation to adverse environmental factors.
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Affiliation(s)
- Elena V Seliverstova
- Laboratory of Renal Physiology, Sechenov Institute of Evolutionary Physiology and Biochemistry of the Russian Academy of Sciences, Torez Av., 44, Saint Petersburg, 194223, Russian Federation.
| | - Natalya P Prutskova
- Laboratory of Renal Physiology, Sechenov Institute of Evolutionary Physiology and Biochemistry of the Russian Academy of Sciences, Torez Av., 44, Saint Petersburg, 194223, Russian Federation
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Jones G, Zeng L, Kim J. Mechanism-Based Pharmacokinetic Modeling of Absorption and Disposition of a Deferoxamine-Based Nanochelator in Rats. Mol Pharm 2023; 20:481-490. [PMID: 36378830 DOI: 10.1021/acs.molpharmaceut.2c00737] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Deferoxamine (DFO) is an effective FDA-approved iron chelator. However, its use is considerably limited by off-target toxicities and an extremely cumbersome dose regimen with daily infusions. The recent development of a deferoxamine-based nanochelator (DFO-NP) with selective renal excretion has shown promise in ameliorating animal models of iron overload with a substantially improved safety profile. To further the preclinical development of this promising nanochelator and to inform on the feasibility of clinical development, it is necessary to fully characterize the dose and administration-route-dependent pharmacokinetics and to develop predictive pharmacokinetic (PK) models describing absorption and disposition. Herein, we have evaluated the absorption, distribution, and elimination of DFO-NPs after intravenous and subcutaneous (SC) injection at therapeutically relevant doses in Sprague Dawley rats. We also characterized compartment-based model structures and identified model-based parameters to quantitatively describe the PK of DFO-NPs. Our modeling efforts confirmed that disposition could be described using a three-compartment mamillary model with elimination and saturable reabsorption both occurring from the third compartment. We also determined that absorption was nonlinear and best described by parallel saturable and first-order processes. Finally, we characterized a novel pathway for saturable SC absorption of an ultrasmall organic nanoparticle directly into the systemic circulation, which offers a novel strategy for improving drug exposure for nanotherapeutics.
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Affiliation(s)
- Gregory Jones
- Department of Pharmaceutical Sciences, Northeastern University, Boston, Massachusetts 02115, United States
| | - Lingxue Zeng
- Department of Biomedical and Nutritional Sciences, University of Massachusetts Lowell, Lowell, Massachusetts 01854, United States
| | - Jonghan Kim
- Department of Biomedical and Nutritional Sciences, University of Massachusetts Lowell, Lowell, Massachusetts 01854, United States
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Kozyraki R, Verroust P, Cases O. Cubilin, the intrinsic factor-vitamin B12 receptor. VITAMINS AND HORMONES 2022; 119:65-119. [PMID: 35337634 DOI: 10.1016/bs.vh.2022.01.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Cubilin (CUBN), the intrinsic factor-vitamin B12 receptor is a large endocytic protein involved in various physiological functions: vitamin B12 uptake in the gut; reabsorption of albumin and maturation of vitamin D in the kidney; nutrient delivery during embryonic development. Cubilin is an atypical receptor, peripherally associated to the plasma membrane. The transmembrane proteins amnionless (AMN) and Lrp2/Megalin are the currently known molecular partners contributing to plasma membrane transport and internalization of Cubilin. The role of Cubilin/Amn complex in the handling of vitamin B12 in health and disease has extensively been studied and so is the role of the Cubilin-Lrp2 tandem in renal pathophysiology. Accumulating evidence strongly supports a role of Cubilin in some developmental defects including impaired closure of the neural tube. Are these defects primarily caused by the dysfunction of a specific Cubilin ligand or are they secondary to impaired vitamin B12 or protein uptake? We will present the established Cubilin functions, discuss the developmental data and provide an overview of the emerging implications of Cubilin in the field of cardiovascular disease and cancer pathogenesis.
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Affiliation(s)
- Renata Kozyraki
- Centre de Recherche des Cordeliers, Sorbonne Université, INSERM, Université de Paris, Paris, France.
| | - Pierre Verroust
- Centre de Recherche des Cordeliers, Sorbonne Université, INSERM, Université de Paris, Paris, France
| | - Olivier Cases
- Centre de Recherche des Cordeliers, Sorbonne Université, INSERM, Université de Paris, Paris, France
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Agarwal S, Sudhini YR, Polat OK, Reiser J, Altintas MM. Renal cell markers: lighthouses for managing renal diseases. Am J Physiol Renal Physiol 2021; 321:F715-F739. [PMID: 34632812 DOI: 10.1152/ajprenal.00182.2021] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Kidneys, one of the vital organs in our body, are responsible for maintaining whole body homeostasis. The complexity of renal function (e.g., filtration, reabsorption, fluid and electrolyte regulation, and urine production) demands diversity not only at the level of cell types but also in their overall distribution and structural framework within the kidney. To gain an in depth molecular-level understanding of the renal system, it is imperative to discern the components of kidney and the types of cells residing in each of the subregions. Recent developments in labeling, tracing, and imaging techniques have enabled us to mark, monitor, and identify these cells in vivo with high efficiency in a minimally invasive manner. In this review, we summarize different cell types, specific markers that are uniquely associated with those cell types, and their distribution in the kidney, which altogether make kidneys so special and different. Cellular sorting based on the presence of certain proteins on the cell surface allowed for the assignment of multiple markers for each cell type. However, different studies using different techniques have found contradictions in cell type-specific markers. Thus, the term "cell marker" might be imprecise and suboptimal, leading to uncertainty when interpreting the data. Therefore, we strongly believe that there is an unmet need to define the best cell markers for a cell type. Although the compendium of renal-selective marker proteins presented in this review is a resource that may be useful to researchers, we acknowledge that the list may not be necessarily exhaustive.
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Affiliation(s)
- Shivangi Agarwal
- Department of Internal Medicine, Rush University, Chicago, Illinois
| | | | - Onur K Polat
- Department of Internal Medicine, Rush University, Chicago, Illinois
| | - Jochen Reiser
- Department of Internal Medicine, Rush University, Chicago, Illinois
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Sheikh-Hamad D, Holliday M, Li Q. Megalin-Mediated Trafficking of Mitochondrial Intracrines: Relevance to Signaling and Metabolism. JOURNAL OF CELLULAR IMMUNOLOGY 2021; 3:364-369. [PMID: 35098216 PMCID: PMC8793748] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The multi-ligand binding protein megalin (LRP2) is ubiquitously expressed and facilitates cell uptake of hormones, nutrients and vitamins. We have recently shown megalin is present in the mitochondria of cultured epithelial and mesenchymal cells, as well as many organs and tissues. Mitochondrial megalin associates with stanniocalcin-1 and SIRT3; two proteins that promote anti-oxidant defenses. Megalin shuttles mitochondrial intracrines (angiotensin II, stanniocalcin-1 and TGF-β) from the cell surface to the mitochondria through the retrograde early endosome to Golgi pathway and requires Rab32. Deletion of megalin impairs mitochondrial respiration and glycolysis. This pathway overlaps molecular and vesicular trafficking defects common to Donai Barrow and Lowe syndromes, suggesting that mitochondrial intracrine signaling defects may contribute to the pathogenesis of these diseases.
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Affiliation(s)
- David Sheikh-Hamad
- Division of Nephrology and Selzman Institute for Kidney Health, Department of Medicine, Baylor College of Medicine, Houston, Texas, 77030 USA,Center for Translational Research on Inflammatory Diseases (CTRID), Michael E. Debakey VAMC, Houston, Texas, 77030 USA,Correspondence should be addressed to David Sheikh-Hamad;
| | - Michael Holliday
- Division of Nephrology and Selzman Institute for Kidney Health, Department of Medicine, Baylor College of Medicine, Houston, Texas, 77030 USA,Center for Translational Research on Inflammatory Diseases (CTRID), Michael E. Debakey VAMC, Houston, Texas, 77030 USA
| | - Qingtian Li
- Division of Nephrology and Selzman Institute for Kidney Health, Department of Medicine, Baylor College of Medicine, Houston, Texas, 77030 USA
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Verta R, Gurrieri M, Borga S, Benetti E, Pollicino P, Cavalli R, Thurmond RL, Chazot PL, Pini A, Rosa AC, Grange C. The Interplay between Histamine H 4 Receptor and the Kidney Function: The Lesson from H 4 Receptor Knockout Mice. Biomolecules 2021; 11:biom11101517. [PMID: 34680152 PMCID: PMC8533779 DOI: 10.3390/biom11101517] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Revised: 09/30/2021] [Accepted: 10/13/2021] [Indexed: 01/15/2023] Open
Abstract
Previous studies implicated the histamine H4 receptor in renal pathophysiology. The aim here is to elucidate the role of this receptor on renal function using H4 receptor knockout mice (H4R-/-). Healthy and diabetic H4R-/- mice compared to their C57BL/6J wild-type counterpart for renal function and the expression of crucial tubular proteins. H4R-/- and wild-type mice, matched for ages, showed comparable weight gain curves reaching similar median weight at the end of the study. However, H4R-/- mice displayed a higher basal glycemia. H4R-/- mice showed a lower urine 24 h outflow, and albumin-to-creatinine ratio (ACR) compared to wild-type mice. Consistently, H4R-/- mice presented a higher expression of megalin and a lower basal expression of the sodium-hydrogen exchanger (NHE)3 and aquaporin (AQP)2. According to these basal differences, diabetic H4R-/- mice developed more severe hyperglycemia and a higher 24 h urine volume, but a lower increase in ACR and decrease in urine pH were observed. These events were paralleled by a reduced NHE3 over-expression and megalin loss in diabetic H4R-/- mice. The AQP1 and AQP7 patterns were also different between H4R-/- and wild-type diabetic mice. The collected results highlight the role of the histamine H4 receptor in the control of renal reabsorption processes, particularly albumin uptake.
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Affiliation(s)
- Roberta Verta
- Department of Biotechnology and Health Sciences, University of Turin, C.So Dogliotti 14, 10126 Turin, Italy;
| | - Maura Gurrieri
- Department of Scienza e Tecnologia del Farmaco, University of Turin, Via P. Giuria 9, 10125 Turin, Italy; (M.G.); (S.B.); (E.B.); (R.C.)
| | - Sara Borga
- Department of Scienza e Tecnologia del Farmaco, University of Turin, Via P. Giuria 9, 10125 Turin, Italy; (M.G.); (S.B.); (E.B.); (R.C.)
| | - Elisa Benetti
- Department of Scienza e Tecnologia del Farmaco, University of Turin, Via P. Giuria 9, 10125 Turin, Italy; (M.G.); (S.B.); (E.B.); (R.C.)
| | - Paolo Pollicino
- Direzione Ricerca e Terza Missione, University of Turin, Via Bogino 9 Torino, 10123 Turin, Italy;
| | - Roberta Cavalli
- Department of Scienza e Tecnologia del Farmaco, University of Turin, Via P. Giuria 9, 10125 Turin, Italy; (M.G.); (S.B.); (E.B.); (R.C.)
| | - Robin L. Thurmond
- Janssen Research & Development, LLC, 3210 Merryfield Row, San Diego, CA 92121, USA;
| | - Paul L. Chazot
- Department of Biosciences and Wolfson Research Institute, Durham University, South Road, Durham DH1 3LE, UK;
| | - Alessandro Pini
- Department of Clinical and Experimental Medicine, University of Florence, Viale Pieraccini 6, 50139 Florence, Italy;
| | - Arianna Carolina Rosa
- Department of Scienza e Tecnologia del Farmaco, University of Turin, Via P. Giuria 9, 10125 Turin, Italy; (M.G.); (S.B.); (E.B.); (R.C.)
- Correspondence: ; Tel.: +39-011-6707955
| | - Cristina Grange
- Department of Medical Sciences, University of Turin, C.So Dogliotti 14, 10126 Turin, Italy;
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Molecular determinants of protein reabsorption in the amphibian kidneys. Acta Histochem 2021; 123:151760. [PMID: 34303296 DOI: 10.1016/j.acthis.2021.151760] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Revised: 06/28/2021] [Accepted: 07/11/2021] [Indexed: 11/23/2022]
Abstract
Participation of molecular determinants of endocytosis in the processes of glomerular filtration and tubular reabsorption of albumin and lysozyme in the mesonephros of grass frogs (Rana temporaria L.), lake frogs (Rana ridibunda P.), and newts (Triturus vulgaris L.) is investigated. In all studied species, the constitutive expression of endocytic receptors in proximal tubule (PT) cells is established using immunofluorescence microscopy and immunoblotting. The certain stages of lysozyme and albumin endocytosis involving megalin/LRP2, cubilin, clathrin and protein Rab11 are detailed, and the central role of ligand-induced megalin/LRP2 activity in this process is shown. Increased ligand-induced expression for clathrin and Rab11was also found. In grass frogs, the different patterns of endocytic receptors and both absorbed proteins in the initial parts of proximal tubules suggest the proximo-distal specialization of absorptive processes along these tubule segments, similar to this in more complex mammalian nephrons. This data, as well as the revealed peculiarities of ligand-receptor interactions during intracellular trafficking of proteins prove that megalin is mainly involved in the absorption of lysozyme. At the same time, albumin absorption is mediated by both receptors, or cubilin contributes the most. The detection of endocytic receptor in glomerular structural elements in frogs and newts suggests the participation of filtration barrier components in endocytosis of filterable proteins. The results represent a new contribution to the study of the fundamental mechanisms of renal protein uptake in the amphibian mesonephros as a more primitive kidney compared to mammalian metanephros.
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Cong J, Chang SJ, Thomsen JS, Andreasen A, Chen X, Xing J, Zhang J, Gu L, Zhai XY. Ultrastructural identification of developing proximal tubules based on three-dimensional reconstruction. Vet Med Sci 2021; 7:1989-1998. [PMID: 34236772 PMCID: PMC8464306 DOI: 10.1002/vms3.558] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
BACKGROUND The cellular mechanisms involved in the development of proximal tubules are not only associated with morphogenesis in fetal life, but also with restoration of damaged tubules in adulthood. Knowledge about morphological features of cell differentiation and proliferation along the developing tubule is insufficient, which hinders identification of the cellular origin. OBJECTIVES This study aimed to investigate ultrastructures of the proximal tubule at different stages of nephrogenesis. METHODS Electron microscopy was used and guided by computer-assisted tubular tracing to identify the cellular structures. RESULTS Renal vesicles and S-shaped bodies revealed more proliferative features, such as densely-packed fusiform-shaped cells with numerous protein-producing organelles than membrane specializations typical for mature tubules. At the capillary-loop stage the proximal tubules demonstrated all characteristics of the mature tubules, but not as developed, including shorter but densely packed microvilli, fewer lateral processes with cell-cell contacts, lower basal membrane infoldings, and lower mitochondrial volume density. However, they exhibited an elaborated endocytic system above the nucleus, indicating a membrane transport is being established. Abundant free- and endoplasmic reticulum-adhered ribosomes and Golgi complexes reflected active protein synthesis for cell growth and proliferation. Interestingly, electron dense cells were occasionally intermixed with electron lucent cells characterized by various organelles in less cytosol and a larger nucleus with abundant euchromatin, which is a feature of active proliferation. CONCLUSIONS These ultrastructures indicate that the morphogenesis of the developing proximal tubule corresponds to the gradually established physiological activities. The two different cellular electron densities may suggest distinctive differentiation of the cells along the tubule.
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Affiliation(s)
- Jing Cong
- Department of Histology and Embryology, Basic Medical College, China Medical University, Shenyang, China.,Department of Histology and Embryology, Shenyang Medical College, Shenyang, China
| | - Shi-Jie Chang
- Department of Biomedical Engineering, College of Fundamental Science, China Medical University, Shenyang, China
| | | | - Arne Andreasen
- Department of Biomedicine-Anatomy, Aarhus University, Aarhus, Denmark
| | - Xue Chen
- Department of Histology and Embryology, Basic Medical College, China Medical University, Shenyang, China
| | - Jia Xing
- Department of Histology and Embryology, Basic Medical College, China Medical University, Shenyang, China
| | - Jie Zhang
- Department of Histology and Embryology, Basic Medical College, China Medical University, Shenyang, China
| | - Ling Gu
- Department of Histology and Embryology, Basic Medical College, China Medical University, Shenyang, China
| | - Xiao-Yue Zhai
- Department of Histology and Embryology, Basic Medical College, China Medical University, Shenyang, China
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Barwinska D, El-Achkar TM, Melo Ferreira R, Syed F, Cheng YH, Winfree S, Ferkowicz MJ, Hato T, Collins KS, Dunn KW, Kelly KJ, Sutton TA, Rovin BH, Parikh SV, Phillips CL, Dagher PC, Eadon MT. Molecular characterization of the human kidney interstitium in health and disease. SCIENCE ADVANCES 2021; 7:7/7/eabd3359. [PMID: 33568476 PMCID: PMC7875540 DOI: 10.1126/sciadv.abd3359] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Accepted: 12/23/2020] [Indexed: 05/23/2023]
Abstract
The gene expression signature of the human kidney interstitium is incompletely understood. The cortical interstitium (excluding tubules, glomeruli, and vessels) in reference nephrectomies (N = 9) and diabetic kidney biopsy specimens (N = 6) was laser microdissected (LMD) and sequenced. Samples underwent RNA sequencing. Gene signatures were deconvolved using single nuclear RNA sequencing (snRNAseq) data derived from overlapping specimens. Interstitial LMD transcriptomics uncovered previously unidentified markers including KISS1, validated with in situ hybridization. LMD transcriptomics and snRNAseq revealed strong correlation of gene expression within corresponding kidney regions. Relevant enriched interstitial pathways included G-protein coupled receptor. binding and collagen biosynthesis. The diabetic interstitium was enriched for extracellular matrix organization and small-molecule catabolism. Cell type markers with unchanged expression (NOTCH3, EGFR, and HEG1) and those down-regulated in diabetic nephropathy (MYH11, LUM, and CCDC3) were identified. LMD transcriptomics complements snRNAseq; together, they facilitate mapping of interstitial marker genes to aid interpretation of pathophysiology in precision medicine studies.
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Affiliation(s)
- Daria Barwinska
- Department of Medicine, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Tarek M El-Achkar
- Department of Medicine, Indiana University School of Medicine, Indianapolis, IN 46202, USA.
- Roudebush Veteran Affairs Medical Center, Indianapolis, IN 46202, USA
- Department of Anatomy, Cell Biology and Physiology, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Ricardo Melo Ferreira
- Department of Medicine, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Farooq Syed
- Department of Pediatrics, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Ying-Hua Cheng
- Department of Medicine, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Seth Winfree
- Department of Medicine, Indiana University School of Medicine, Indianapolis, IN 46202, USA
- Department of Anatomy, Cell Biology and Physiology, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Michael J Ferkowicz
- Department of Medicine, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Takashi Hato
- Department of Medicine, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Kimberly S Collins
- Department of Medicine, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Kenneth W Dunn
- Department of Medicine, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Katherine J Kelly
- Department of Medicine, Indiana University School of Medicine, Indianapolis, IN 46202, USA
- Roudebush Veteran Affairs Medical Center, Indianapolis, IN 46202, USA
| | - Timothy A Sutton
- Department of Medicine, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Brad H Rovin
- Division of Nephrology, Department of Medicine, Ohio State University Wexner Medical Center, OH 433210, USA
| | - Samir V Parikh
- Division of Nephrology, Department of Medicine, Ohio State University Wexner Medical Center, OH 433210, USA
| | - Carrie L Phillips
- Division of Pathology, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Pierre C Dagher
- Department of Medicine, Indiana University School of Medicine, Indianapolis, IN 46202, USA
- Roudebush Veteran Affairs Medical Center, Indianapolis, IN 46202, USA
| | - Michael T Eadon
- Department of Medicine, Indiana University School of Medicine, Indianapolis, IN 46202, USA.
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Gualdani R, Seghers F, Yerna X, Schakman O, Tajeddine N, Achouri Y, Tissir F, Devuyst O, Gailly P. Mechanical activation of TRPV4 channels controls albumin reabsorption by proximal tubule cells. Sci Signal 2020; 13:13/653/eabc6967. [DOI: 10.1126/scisignal.abc6967] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Defects in protein reabsorption by the proximal tubule are toxic for epithelial cells in the nephron and may result in nephropathy. In this study, we showed that the ion channel TRPV4 modulated the endocytosis of albumin and low–molecular weight proteins in the proximal tubule. TRPV4 was found at the basolateral side of proximal tubule cells, and its mechanical activation by cell stretching induced Ca2+ entry into the cytosol, which promoted endocytosis. Trpv4−/− mice presented with mild proximal tubule dysfunction under basal conditions. To challenge endocytic function, the permeability of the glomerular filter was altered by systemic delivery of angiotensin II. The proteinuria induced by this treatment was more severe in Trpv4−/− than in Trpv4+/+ mice. Injecting antibodies against the glomerular basement membrane to induce glomerulonephritis is a more pathophysiologically relevant method of impairing glomerular filter permeability. Albuminuria was more severe in mice that lacked TRPV4 specifically in the proximal tubule than in control mice. These results emphasize the importance of TRPV4 in sensing pressure in the proximal tubule in response to variations in the amount of ultrafiltrate and unveil a mechanism that controls protein reabsorption.
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Affiliation(s)
- Roberta Gualdani
- Université catholique de Louvain, Institute of Neuroscience, Cell Physiology, av. Mounier 53/B1.53.17, B-1200 Brussels, Belgium
| | - François Seghers
- Université catholique de Louvain, Institute of Neuroscience, Cell Physiology, av. Mounier 53/B1.53.17, B-1200 Brussels, Belgium
| | - Xavier Yerna
- Université catholique de Louvain, Institute of Neuroscience, Cell Physiology, av. Mounier 53/B1.53.17, B-1200 Brussels, Belgium
| | - Olivier Schakman
- Université catholique de Louvain, Institute of Neuroscience, Cell Physiology, av. Mounier 53/B1.53.17, B-1200 Brussels, Belgium
| | - Nicolas Tajeddine
- Université catholique de Louvain, Institute of Neuroscience, Cell Physiology, av. Mounier 53/B1.53.17, B-1200 Brussels, Belgium
| | - Younès Achouri
- Université catholique de Louvain, de Duve Institute, Transgenic Core Facility, av. Hippocrate 75/B1.75.09, B-1200 Brussels, Belgium
| | - Fadel Tissir
- Université catholique de Louvain, Institute of Neuroscience, Developmental Neurobiology, av. Hippocrate 73/B1.73.16, B-1200 Brussels, Belgium
| | - Olivier Devuyst
- University of Zurich, Institute of Physiology, Winterthurerstr. 190, CH-8057 Zurich, Switzerland
| | - Philippe Gailly
- Université catholique de Louvain, Institute of Neuroscience, Cell Physiology, av. Mounier 53/B1.53.17, B-1200 Brussels, Belgium
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12
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Long KR, Rbaibi Y, Gliozzi ML, Ren Q, Weisz OA. Differential kidney proximal tubule cell responses to protein overload by albumin and its ligands. Am J Physiol Renal Physiol 2020; 318:F851-F859. [PMID: 32068462 DOI: 10.1152/ajprenal.00490.2019] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Albuminuria is frequently associated with proximal tubule (PT) cytotoxicity that can feed back to cause glomerular damage and exacerbate kidney disease. PT cells express megalin and cubilin receptors that bind to and internalize albumin over a broad concentration range. How the exposure to high concentrations of albumin leads to PT cytotoxicity remains unclear. Fatty acids and other ligands bound to albumin are known to trigger production of reactive oxygen species (ROS) that impair PT function. Alternatively or in addition, uptake of high concentrations of albumin may overload the endocytic pathway and elicit downstream responses. Here, we used a well-differentiated PT cell culture model with high endocytic capacity to dissect the effects of albumin versus its ligands on endocytic uptake and degradation of albumin, production of ROS, and cell viability. Cellular responses differed dramatically, depending on the preparation of albumin tested. Knockdown of megalin or cubilin failed to prevent ROS production mediated by albumin ligands, suggesting that receptor-mediated internalization of albumin was not necessary to trigger cellular responses to albumin ligands. Moreover, albumin induced cytotoxic responses when added to the basolateral surface of PT cells. Whereas overnight incubation with high concentrations of fatty acid-free albumin had no overt effects on cell function or viability, lysosomal degradation kinetics were slowed upon longer exposure, consistent with overload of the PT endocytic/degradative pathway. Together, the results of our study demonstrate that the PT responds independently to albumin and to its ligands and suggest that the consequences of albumin overload in vivo may be dependent on metabolic state.
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Affiliation(s)
- Kimberly R Long
- Renal-Electrolyte Division, Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - Youssef Rbaibi
- Renal-Electrolyte Division, Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - Megan L Gliozzi
- Renal-Electrolyte Division, Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - Qidong Ren
- School of Medicine, Tsinghua University, Beijing, China
| | - Ora A Weisz
- Renal-Electrolyte Division, Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
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13
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Zhao X, Chen X, Chima A, Zhang Y, George J, Cobbs A, Emmett N. Albumin induces CD44 expression in glomerular parietal epithelial cells by activating extracellular signal-regulated kinase 1/2 pathway. J Cell Physiol 2019; 234:7224-7235. [PMID: 30362534 PMCID: PMC6344259 DOI: 10.1002/jcp.27477] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2018] [Accepted: 09/04/2018] [Indexed: 01/21/2023]
Abstract
De novo expression of CD44 in glomerular parietal epithelial cells (PECs) leads to a prosclerotic and migratory PEC phenotype in glomerulosclerosis. However, the regulatory mechanisms underlying CD44 expression by activated PECs remain largely unknown. This study was performed to examine the mediators responsible for CD44 induction in glomerular PECs in association with diabetes. CD44 expression and localization were evaluated in the glomeruli of Zucker diabetic rat kidneys and primary cultured PECs upon albumin stimulation. Real-time polymerase chain reaction confirmed an albuminuria-associated upregulation of the CD44 gene in the glomeruli of diabetic rats. Immunostaining analysis of diabetic kidneys further revealed an increase in CD44 in hypertrophic PECs, which often contain albumin-positive vesicles. Losartan treatment significantly attenuated albuminuria and lowered CD44 protein levels in the diabetic kidneys. In primary cultured rat PECs, rat serum albumin (0.25-1 mg/ml) caused a dose-dependent upregulation of CD44, claudin-1, and megalin protein expression, which was accompanied by an activation of extracellular signal-regulated kinase1/2 (ERK1/2) signaling. Albumin-induced CD44 and claudin-1 expression were greatly suppressed in the presence of the ERK1/2 inhibitor, U0126. In addition, knockdown of megalin by small interfering RNA interference in PECs resulted in a significant reduction of albumin-induced CD44 and claudin-1 proteins. Taken together, our results demonstrate that albumin induces CD44 expression by PECs via the activation of the ERK signaling pathway, which is partially mediated by endocytic receptor megalin.
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Affiliation(s)
- Xueying Zhao
- Department of Physiology, Morehouse School of Medicine, Atlanta, Georgia
| | - Xiaoming Chen
- Department of Physiology, Morehouse School of Medicine, Atlanta, Georgia
| | - Ashmeer Chima
- Department of Physiology, Morehouse School of Medicine, Atlanta, Georgia
| | - Yuanyuan Zhang
- Department of Physiology, Morehouse School of Medicine, Atlanta, Georgia
| | - Jasmine George
- Department of Physiology, Morehouse School of Medicine, Atlanta, Georgia
| | - Alyssa Cobbs
- Department of Physiology, Morehouse School of Medicine, Atlanta, Georgia
| | - Nerimiah Emmett
- Department of Physiology, Morehouse School of Medicine, Atlanta, Georgia
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14
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De Miguel C, Sedaka R, Kasztan M, Lever JM, Sonnenberger M, Abad A, Jin C, Carmines PK, Pollock DM, Pollock JS. Tauroursodeoxycholic acid (TUDCA) abolishes chronic high salt-induced renal injury and inflammation. Acta Physiol (Oxf) 2019; 226:e13227. [PMID: 30501003 DOI: 10.1111/apha.13227] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2017] [Revised: 10/23/2018] [Accepted: 11/22/2018] [Indexed: 12/23/2022]
Abstract
AIM Chronic high salt intake exaggerates renal injury and inflammation, especially with the loss of functional ETB receptors. Tauroursodeoxycholic acid (TUDCA) is a chemical chaperone and bile salt that is approved for the treatment of hepatic diseases. Our aim was to determine whether TUDCA is reno-protective in a model of ETB receptor deficiency with chronic high salt-induced renal injury and inflammation. METHODS ETB -deficient and transgenic control rats were placed on normal (0.8% NaCl) or high salt (8% NaCl) diet for 3 weeks, receiving TUDCA (400 mg/kg/d; ip) or vehicle. Histological and biochemical markers of kidney injury, renal cell death and renal inflammation were assessed. RESULTS In ETB -deficient rats, high salt diet significantly increased glomerular and proximal tubular histological injury, proteinuria, albuminuria, excretion of tubular injury markers KIM-1 and NGAL, renal cortical cell death and renal CD4+ T cell numbers. TUDCA treatment increased proximal tubule megalin expression as well as prevented high salt diet-induced glomerular and tubular damage in ETB -deficient rats, as indicated by reduced kidney injury markers, decreased glomerular permeability and proximal tubule brush border restoration, as well as reduced renal inflammation. However, TUDCA had no significant effect on blood pressure. CONCLUSIONS TUDCA protects against the development of glomerular and proximal tubular damage, decreases renal cell death and inflammation in the renal cortex in rats with ETB receptor dysfunction on a chronic high salt diet. These results highlight the potential use of TUDCA as a preventive tool against chronic high salt induced renal damage.
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Affiliation(s)
- Carmen De Miguel
- Section of Cardio‐Renal Physiology and Medicine, Division of Nephrology, Department of Medicine University of Alabama at Birmingham Birmingham Alabama
| | - Randee Sedaka
- Section of Cardio‐Renal Physiology and Medicine, Division of Nephrology, Department of Medicine University of Alabama at Birmingham Birmingham Alabama
| | - Malgorzata Kasztan
- Section of Cardio‐Renal Physiology and Medicine, Division of Nephrology, Department of Medicine University of Alabama at Birmingham Birmingham Alabama
| | - Jeremie M. Lever
- Division of Nephrology, Department of Medicine University of Alabama at Birmingham Birmingham Alabama
| | - Michelle Sonnenberger
- Section of Cardio‐Renal Physiology and Medicine, Division of Nephrology, Department of Medicine University of Alabama at Birmingham Birmingham Alabama
| | - Andrew Abad
- Section of Cardio‐Renal Physiology and Medicine, Division of Nephrology, Department of Medicine University of Alabama at Birmingham Birmingham Alabama
| | - Chunhua Jin
- Section of Cardio‐Renal Physiology and Medicine, Division of Nephrology, Department of Medicine University of Alabama at Birmingham Birmingham Alabama
| | - Pamela K. Carmines
- Department of Cellular and Integrative Physiology University of Nebraska Medical Center Omaha Nebraska
| | - David M. Pollock
- Section of Cardio‐Renal Physiology and Medicine, Division of Nephrology, Department of Medicine University of Alabama at Birmingham Birmingham Alabama
| | - Jennifer S. Pollock
- Section of Cardio‐Renal Physiology and Medicine, Division of Nephrology, Department of Medicine University of Alabama at Birmingham Birmingham Alabama
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15
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Kozyraki R, Cases O. Cubilin, the Intrinsic Factor-Vitamin B12 Receptor in Development and Disease. Curr Med Chem 2018; 27:3123-3150. [PMID: 30295181 DOI: 10.2174/0929867325666181008143945] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2018] [Revised: 08/11/2018] [Accepted: 08/21/2018] [Indexed: 12/29/2022]
Abstract
Gp280/Intrinsic factor-vitamin B12 receptor/Cubilin (CUBN) is a large endocytic receptor serving multiple functions in vitamin B12 homeostasis, renal reabsorption of protein or toxic substances including albumin, vitamin D-binding protein or cadmium. Cubilin is a peripheral membrane protein consisting of 8 Epidermal Growth Factor (EGF)-like repeats and 27 CUB (defined as Complement C1r/C1s, Uegf, BMP1) domains. This structurally unique protein interacts with at least two molecular partners, Amnionless (AMN) and Lrp2/Megalin. AMN is involved in appropriate plasma membrane transport of Cubilin whereas Lrp2 is essential for efficient internalization of Cubilin and its ligands. Observations gleaned from animal models with Cubn deficiency or human diseases demonstrate the importance of this protein. In this review addressed to basic research and medical scientists, we summarize currently available data on Cubilin and its implication in renal and intestinal biology. We also discuss the role of Cubilin as a modulator of Fgf8 signaling during embryonic development and propose that the Cubilin-Fgf8 interaction may be relevant in human pathology, including in cancer progression, heart or neural tube defects. We finally provide experimental elements suggesting that some aspects of Cubilin physiology might be relevant in drug design.
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Affiliation(s)
- Renata Kozyraki
- INSERM UMRS 1138, Centre de Recherche des Cordeliers, Paris-Diderot University, Paris, France
| | - Olivier Cases
- INSERM UMRS 1138, Centre de Recherche des Cordeliers, Paris-Diderot University, Paris, France
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16
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Elmonem MA, Berlingerio SP, van den Heuvel LP, de Witte PA, Lowe M, Levtchenko EN. Genetic Renal Diseases: The Emerging Role of Zebrafish Models. Cells 2018; 7:cells7090130. [PMID: 30200518 PMCID: PMC6162634 DOI: 10.3390/cells7090130] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2018] [Revised: 08/27/2018] [Accepted: 08/29/2018] [Indexed: 12/14/2022] Open
Abstract
The structural and functional similarity of the larval zebrafish pronephros to the human nephron, together with the recent development of easier and more precise techniques to manipulate the zebrafish genome have motivated many researchers to model human renal diseases in the zebrafish. Over the last few years, great advances have been made, not only in the modeling techniques of genetic diseases in the zebrafish, but also in how to validate and exploit these models, crossing the bridge towards more informative explanations of disease pathophysiology and better designed therapeutic interventions in a cost-effective in vivo system. Here, we review the significant progress in these areas giving special attention to the renal phenotype evaluation techniques. We further discuss the future applications of such models, particularly their role in revealing new genetic diseases of the kidney and their potential use in personalized medicine.
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Affiliation(s)
- Mohamed A Elmonem
- Department of Pediatric Nephrology & Development and Regeneration, University Hospitals Leuven, KU Leuven-University of Leuven, Herestraat 49, Box 817, 3000 Leuven, Belgium.
- Department of Clinical and Chemical Pathology, Faculty of Medicine, Cairo University, 11628 Cairo, Egypt.
| | - Sante Princiero Berlingerio
- Department of Pediatric Nephrology & Development and Regeneration, University Hospitals Leuven, KU Leuven-University of Leuven, Herestraat 49, Box 817, 3000 Leuven, Belgium.
| | - Lambertus P van den Heuvel
- Department of Pediatric Nephrology & Development and Regeneration, University Hospitals Leuven, KU Leuven-University of Leuven, Herestraat 49, Box 817, 3000 Leuven, Belgium.
- Department of Pediatric Nephrology, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands.
| | - Peter A de Witte
- Laboratory for Molecular Bio-Discovery, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven-University of Leuven, 3000 Leuven, Belgium.
| | - Martin Lowe
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester M13 9PL, UK.
| | - Elena N Levtchenko
- Department of Pediatric Nephrology & Development and Regeneration, University Hospitals Leuven, KU Leuven-University of Leuven, Herestraat 49, Box 817, 3000 Leuven, Belgium.
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17
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Abd-Elhamid TH, Elgamal DA, Ali SS, Ali FEM, Hassanein EHM, El-Shoura EAM, Hemeida RAM. Reno-protective effects of ursodeoxycholic acid against gentamicin-induced nephrotoxicity through modulation of NF-κB, eNOS and caspase-3 expressions. Cell Tissue Res 2018; 374:367-387. [PMID: 30078101 DOI: 10.1007/s00441-018-2886-y] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2017] [Accepted: 07/04/2018] [Indexed: 12/13/2022]
Abstract
Gentamicin (GNT) is a potent aminoglycoside antibiotic widely used to treat life-threatening bacterial infections. We aim to investigate the potential protective effect of ursodeoxycholic acid (UDCA) against GNT-induced nephrotoxicity. In this study, 24 male Wistar rats were used and randomly divided into four groups of six animals each. Control group received 0.5% carboxymethyl cellulose orally for 15 days, GNT group received GNT 100 mg/kg/day i.p. for 8 days, UDCA group received UDCA orally for 15 consecutive days at a dose of 60 mg/kg/day suspended in 0.5% carboxymethyl cellulose and UDCA-pretreated group received UDCA orally for 7 days then co-administered with GNT i.p. for 8 days at the same fore-mentioned doses. Serum levels of kidney function parameters (urea, creatinine, uric acid and albumin) were measured. Renal tissues were used to evaluate oxidative stress markers; malonaldehyde (MDA), reduced glutathione (GSH) and the anti-oxidant enzyme superoxide dismutase (SOD) activities and nuclear factor kappa light-chain enhancer of activated B cells (NF-κB) and kidney injury molecule-1 (KIM-1) mRNA levels. Immunohistochemical expression of endothelial nitric oxide synthase (eNOS) and caspase-3 and histological and ultrastructural examination were performed. Treatment with GNT increased the serum levels of renal function parameters and renal MDA, NF-κB and KIM-1 mRNA levels, while it decreased GSH and SOD activities. Marked immunohistochemical expression of caspase-3 was observed after GNT administration while it decreased eNOS expression. Histological and ultrastructural alterations were also evident in renal corpuscles and tubules. In contrast, pretreatment with UDCA reversed changes caused by GNT administration. These results suggest that UDCA ameliorates GNT-induced kidney injury via inhibition of oxidative stress, inflammation and apoptosis.
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Affiliation(s)
- Tarek Hamdy Abd-Elhamid
- Department of Histology and Cell Biology, Faculty of Medicine, Assiut University, Assiut, Egypt.
| | - Dalia A Elgamal
- Department of Histology and Cell Biology, Faculty of Medicine, Assiut University, Assiut, Egypt
| | - Safaa S Ali
- Department of Histology and Cell Biology, Faculty of Medicine, Assiut University, Assiut, Egypt
| | - Fares E M Ali
- Department of Pharmacology, Faculty of Pharmacy, Al-Azhar University, Assiut, Egypt
| | - Emad H M Hassanein
- Department of Pharmacology, Faculty of Pharmacy, Al-Azhar University, Assiut, Egypt
| | - Ehab A M El-Shoura
- Department of Pharmacology, Faculty of Pharmacy, Al-Azhar University, Assiut, Egypt
| | - Ramadan A M Hemeida
- Department of Pharmacology, Faculty of Pharmacy, Al-Azhar University, Assiut, Egypt
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18
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Chapron BD, Chapron A, Phillips B, Okoli MC, Shen DD, Kelly EJ, Himmelfarb J, Thummel KE. Reevaluating the role of megalin in renal vitamin D homeostasis using a human cell-derived microphysiological system. ALTEX-ALTERNATIVES TO ANIMAL EXPERIMENTATION 2018; 35:504-515. [PMID: 29999169 PMCID: PMC6896899 DOI: 10.14573/altex.1803161] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/16/2018] [Accepted: 06/29/2018] [Indexed: 01/08/2023]
Abstract
The role of megalin in the regulation of renal vitamin D homeostasis has previously been evaluated in megalin-knockout mice and rat proximal tubule epithelial cells. We revisited these hypotheses that were previously tested solely in rodent models, this time using a 3-dimensional proximal tubule microphysiological system incorporating primary human proximal tubule epithelial cells. Using this human cell-derived model, we confirmed that 25OHD3 is transported into the human proximal tubule epithelium via megalin-mediated endocytosis while bound to vitamin D binding protein. Building upon these findings, we then evaluated the role of megalin in modulating the cellular uptake and biological activity of 1α,25(OH)2D3. Inhibition of megalin function decreased the 1α,25(OH)2D3-mediated induction of both cytochrome P450 24A1 protein levels and 24-hydroxylation activity following perfusion with vitamin D binding protein and 1α,25(OH)2D3. The potential for reciprocal effects from 1α,25(OH)2D3 on megalin expression were also tested. Contrary to previously published observations from rat proximal tubule epithelial cells, 1α,25(OH)2D3 did not induce megalin gene expression, thus highlighting the potential for meaningful interspecies differences in the homeostatic regulation of megalin in rodents and humans. These findings challenge a recently promoted hypothesis, predicated on the rodent cell data, that attempts to connect 1α,25(OH)2D3-mediated regulation of renal megalin expression and the pathology of chronic kidney disease in humans. In addition to providing specific insights related to the importance of renal megalin in vitamin D homeostasis, these results constitute a proof-of-concept that human-derived microphysiological systems are a suitable replacement for animal models for quantitative pharmacology and physiology research.
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Affiliation(s)
- Brian D Chapron
- Department of Pharmaceutics, University of Washington, Seattle, WA, USA
| | - Alenka Chapron
- Department of Pharmaceutics, University of Washington, Seattle, WA, USA
| | - Brian Phillips
- Department of Pharmaceutics, University of Washington, Seattle, WA, USA
| | - Miracle C Okoli
- Department of Pharmaceutics, University of Washington, Seattle, WA, USA
| | - Danny D Shen
- Department of Pharmaceutics, University of Washington, Seattle, WA, USA
| | - Edward J Kelly
- Department of Pharmaceutics, University of Washington, Seattle, WA, USA
| | | | - Kenneth E Thummel
- Department of Pharmaceutics, University of Washington, Seattle, WA, USA
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19
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Silva-Aguiar RP, Bezerra NCF, Lucena MC, Sirtoli GM, Sudo RT, Zapata-Sudo G, Takiya CM, Pinheiro AAS, Dias WB, Caruso-Neves C. O-GlcNAcylation reduces proximal tubule protein reabsorption and promotes proteinuria in spontaneously hypertensive rats. J Biol Chem 2018; 293:12749-12758. [PMID: 29954945 DOI: 10.1074/jbc.ra118.001746] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2018] [Revised: 06/27/2018] [Indexed: 12/11/2022] Open
Abstract
Hypertensive individuals are at greater risk for developing chronic kidney disease (CKD). Reducing proteinuria has been suggested as a possible therapeutic approach to treat CKD. However, the mechanisms underlying the development of proteinuria in hypertensive conditions are incompletely understood. Cardiac and vascular dysfunction is associated with changes in the O-GlcNAcylation pathway in hypertensive models. We hypothesized that O-GlcNAcylation is also involved in renal damage, especially development of proteinuria, associated with hypertension. Using the spontaneously hypertensive rat (SHR) model, we observed higher renal cortex O-GlcNAcylation, glutamine-fructose aminotransferase (GFAT), and O-GlcNAc transferase (OGT) protein expression, which positively correlated with proteinuria. Interestingly, this was observed in hypertensive, but not pre-hypertensive, rats. Pharmacological inhibition of GFAT decreased renal cortex O-GlcNAcylation, proteinuria, and albuminuria in SHR. Using a proximal tubule cell line, we observed that increased O-GlcNAcylation reduced megalin surface expression and albumin endocytosis in vitro, and the effects were correlated in vivo Moreover, megalin is O-GlcNAcylated both in vitro and in vivo In conclusion, our results demonstrate a new mechanism involved in hypertension-associated proteinuria.
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Affiliation(s)
- Rodrigo Pacheco Silva-Aguiar
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21949-900, Brazil
| | - Nathália C F Bezerra
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21949-900, Brazil
| | - Miguel C Lucena
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21949-900, Brazil
| | - Gabriela M Sirtoli
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21949-900, Brazil
| | - Roberto T Sudo
- Programa de Desenvolvimento de Fármacos, Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-902, Brazil
| | - Gisele Zapata-Sudo
- Programa de Desenvolvimento de Fármacos, Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-902, Brazil
| | - Christina M Takiya
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21949-900, Brazil
| | - Ana Acacia S Pinheiro
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21949-900, Brazil
| | - Wagner Barbosa Dias
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21949-900, Brazil
| | - Celso Caruso-Neves
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21949-900, Brazil; Instituto Nacional de Ciência e Tecnologia em Medicina Regenerativa (INCT-Regenera), Rio de Janeiro 21941-902, Brazil.
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