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Schult L, Halbgebauer R, Karasu E, Huber-Lang M. Glomerular injury after trauma, burn, and sepsis. J Nephrol 2023; 36:2417-2429. [PMID: 37542608 PMCID: PMC10703988 DOI: 10.1007/s40620-023-01718-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2023] [Accepted: 06/23/2023] [Indexed: 08/07/2023]
Abstract
Acute kidney injury development after trauma, burn, or sepsis occurs frequently but remains a scientific and clinical challenge. Whereas the pathophysiological focus has mainly been on hemodynamics and the downstream renal tubular system, little is known about alterations upstream within the glomerulus post trauma or during sepsis. Particularly for the glomerular endothelial cells, mesangial cells, basal membrane, and podocytes, all of which form the glomerular filter, there are numerous in vitro studies on the molecular and functional consequences upon exposure of single cell types to specific damage- or microbial-associated molecular patterns. By contrast, a lack of knowledge exists in the real world regarding the orchestrated inflammatory response of the glomerulus post trauma or burn or during sepsis. Therefore, we aim to provide an overview on the glomerulus as an immune target but also as a perpetrator of the danger response to traumatic and septic conditions, and present major players involved in the context of critical illness. Finally, we highlight research gaps of this rather neglected but worthwhile area to define future molecular targets and therapeutic strategies to prevent or improve the course of AKI after trauma, burn, or sepsis.
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Affiliation(s)
- Lorena Schult
- Institute of Clinical and Experimental Trauma Immunology, University Hospital Ulm, Helmholtzstr. 8/1, 89081, Ulm, Germany
| | - Rebecca Halbgebauer
- Institute of Clinical and Experimental Trauma Immunology, University Hospital Ulm, Helmholtzstr. 8/1, 89081, Ulm, Germany
| | - Ebru Karasu
- Institute of Clinical and Experimental Trauma Immunology, University Hospital Ulm, Helmholtzstr. 8/1, 89081, Ulm, Germany
| | - Markus Huber-Lang
- Institute of Clinical and Experimental Trauma Immunology, University Hospital Ulm, Helmholtzstr. 8/1, 89081, Ulm, Germany.
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Abo Zed SED, Hackl A, Bohl K, Ebert L, Kieckhöfer E, Müller C, Becker K, Fink G, Nüsken KD, Nüsken E, Müller RU, Schermer B, Weber LT. Mycophenolic acid directly protects podocytes by preserving the actin cytoskeleton and increasing cell survival. Sci Rep 2023; 13:4281. [PMID: 36922538 PMCID: PMC10017704 DOI: 10.1038/s41598-023-31326-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2022] [Accepted: 03/09/2023] [Indexed: 03/18/2023] Open
Abstract
Mycophenolate Mofetil (MMF) has an established role as a therapeutic agent in childhood nephrotic syndrome. While other immunosuppressants have been shown to positively affect podocytes, direct effects of MMF on podocytes remain largely unknown. The present study examines the effects of MMF's active component Mycophenolic Acid (MPA) on the transcriptome of podocytes and investigates its biological significance. We performed transcriptomics in cultured murine podocytes exposed to MPA to generate hypotheses on podocyte-specific effects of MPA. Accordingly, we further analyzed biological MPA effects on actin cytoskeleton morphology after treatment with bovine serum albumin (BSA) by immunofluorescence staining, as well as on cell survival following exposure to TNF-α and cycloheximide by neutral red assay. MPA treatment significantly (adjusted p < 0.05) affected expression of 351 genes in podocytes. Gene Ontology term enrichment analysis particularly clustered terms related to actin and inflammation-related cell death. Indeed, quantification of the actin cytoskeleton of BSA treated podocytes revealed a significant increase of thickness and number of actin filaments after treatment with MPA. Further, MPA significantly reduced TNFα and cycloheximide induced cell death. MPA has a substantial effect on the transcriptome of podocytes in vitro, particularly including functional clusters related to non-immune cell dependent mechanisms. This may provide a molecular basis for direct beneficial effects of MPA on the structural integrity and survival of podocytes under pro-inflammatory conditions.
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Affiliation(s)
- Seif El Din Abo Zed
- Faculty of Medicine and University Hospital Cologne, Department of Pediatrics, University of Cologne, Cologne, Germany
- Faculty of Medicine and University Hospital Cologne, Department II of Internal Medicine and Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany
| | - Agnes Hackl
- Faculty of Medicine and University Hospital Cologne, Department of Pediatrics, University of Cologne, Cologne, Germany.
- Faculty of Medicine and University Hospital Cologne, Department II of Internal Medicine and Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany.
| | - Katrin Bohl
- Faculty of Medicine and University Hospital Cologne, Department II of Internal Medicine and Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany
- Cologne Cluster of Excellence on Cellular Stress Responses in Ageing-Associated Diseases (CECAD), University of Cologne, Cologne, Germany
| | - Lena Ebert
- Faculty of Medicine and University Hospital Cologne, Department II of Internal Medicine and Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany
- Cologne Cluster of Excellence on Cellular Stress Responses in Ageing-Associated Diseases (CECAD), University of Cologne, Cologne, Germany
| | - Emilia Kieckhöfer
- Faculty of Medicine and University Hospital Cologne, Department II of Internal Medicine and Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany
- Cologne Cluster of Excellence on Cellular Stress Responses in Ageing-Associated Diseases (CECAD), University of Cologne, Cologne, Germany
| | - Carsten Müller
- Faculty of Medicine and University Hospital Cologne, Pharmacology at the Laboratory Center, Department of Therapeutic Drug Monitoring DE, University of Cologne, Cologne, Germany
| | - Kerstin Becker
- Faculty of Medicine and University Hospital Cologne, Cologne Center for Genomics (CCG), University of Cologne, Cologne, Germany
| | - Gregor Fink
- Faculty of Medicine and University Hospital Cologne, Department of Pediatrics, University of Cologne, Cologne, Germany
| | - Kai-Dietrich Nüsken
- Faculty of Medicine and University Hospital Cologne, Department of Pediatrics, University of Cologne, Cologne, Germany
| | - Eva Nüsken
- Faculty of Medicine and University Hospital Cologne, Department of Pediatrics, University of Cologne, Cologne, Germany
| | - Roman-Ulrich Müller
- Faculty of Medicine and University Hospital Cologne, Department II of Internal Medicine and Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany
- Cologne Cluster of Excellence on Cellular Stress Responses in Ageing-Associated Diseases (CECAD), University of Cologne, Cologne, Germany
- Faculty of Medicine and University Hospital Cologne, Center for Rare Kidney Diseases Cologne, University of Cologne, Cologne, Germany
| | - Bernhard Schermer
- Faculty of Medicine and University Hospital Cologne, Department II of Internal Medicine and Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany
- Cologne Cluster of Excellence on Cellular Stress Responses in Ageing-Associated Diseases (CECAD), University of Cologne, Cologne, Germany
| | - Lutz T Weber
- Faculty of Medicine and University Hospital Cologne, Department of Pediatrics, University of Cologne, Cologne, Germany
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Yoshida T, Latt KZ, Rosenberg AZ, Shrivastav S, Heymann J, Halushka MK, Winkler CA, Kopp JB. Transcriptomic Analysis of Human Podocytes In Vitro: Effects of Differentiation and APOL1 Genotype. Kidney Int Rep 2022; 8:164-178. [PMID: 36644347 PMCID: PMC9831945 DOI: 10.1016/j.ekir.2022.10.011] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Revised: 10/03/2022] [Accepted: 10/11/2022] [Indexed: 11/06/2022] Open
Abstract
Introduction The mechanisms in podocytes that mediate the pathologic effects of the APOL1 high-risk (HR) variants remain incompletely understood, although various molecular and cellular mechanisms have been proposed. We previously established conditionally immortalized human urine-derived podocyte-like epithelial cell (HUPEC) lines to investigate APOL1 HR variant-induced podocytopathy. Methods We conducted comprehensive transcriptomic analysis, including mRNA, microRNA (miRNA), and transfer RNA fragments (tRFs), to characterize the transcriptional profiles in undifferentiated and differentiated HUPEC with APOL1 HR (G1/G2, 2 cell lines) and APOL1 low-risk (LR) (G0/G0, 2 cell lines) genotypes. We reanalyzed single-cell RNA-seq data from urinary podocytes from focal segmental glomerulosclerosis (FSGS) subjects to characterize the effect of APOL1 genotypes on podocyte transcriptomes. Results Differential expression analysis showed that the ribosomal pathway was one of the most enriched pathways, suggesting that altered function of the translation initiation machinery may contribute to APOL1 variant-induced podocyte injury. Expression of genes related to the elongation initiation factor 2 pathway was also enriched in the APOL1 HR urinary podocytes from single-cell RNA-seq, supporting a prior report on the role of this pathway in APOL1-associated cell injury. Expression of microRNA and tRFs were analyzed, and the profile of small RNAs differed by both differentiation status and APOL1 genotype. Conclusion We have profiled the transcriptomic landscape of human podocytes, including mRNA, miRNA, and tRF, to characterize the effects of differentiation and of different APOL1 genotypes. The candidate pathways, miRNAs, and tRFs described here expand understanding of APOL1-associated podocytopathies.
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Affiliation(s)
- Teruhiko Yoshida
- Kidney Disease Section, Kidney Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, USA,Correspondence: Teruhiko Yoshida, Kidney Disease Section, Kidney Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, 10 Center Drive, 3N104, Bethesda, Maryland 20892-1268, USA.
| | - Khun Zaw Latt
- Kidney Disease Section, Kidney Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Avi Z. Rosenberg
- Department of Pathology, Johns Hopkins Medical Institutions, Baltimore, Maryland, USA
| | - Shashi Shrivastav
- Kidney Disease Section, Kidney Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Jurgen Heymann
- Kidney Disease Section, Kidney Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Marc K. Halushka
- Department of Pathology, Johns Hopkins Medical Institutions, Baltimore, Maryland, USA
| | - Cheryl A. Winkler
- Frederick National Laboratory for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, Maryland, USA
| | - Jeffrey B. Kopp
- Kidney Disease Section, Kidney Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, USA
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Bejoy J, Farry JM, Peek JL, Cabatu MC, Williams FM, Welch RC, Qian ES, Woodard LE. Podocytes derived from human induced pluripotent stem cells: characterization, comparison, and modeling of diabetic kidney disease. Stem Cell Res Ther 2022; 13:355. [PMID: 35883199 PMCID: PMC9327311 DOI: 10.1186/s13287-022-03040-6] [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] [Received: 04/28/2022] [Accepted: 07/06/2022] [Indexed: 02/05/2023] Open
Abstract
BACKGROUND In diabetic kidney disease, high glucose damages specialized cells called podocytes that filter blood in the glomerulus. In vitro culture of podocytes is crucial for modeling of diabetic nephropathy and genetic podocytopathies and to complement animal studies. Recently, several methods have been published to derive podocytes from human-induced pluripotent stem cells (iPSCs) by directed differentiation. However, these methods have major variations in media composition and have not been compared. METHODS We characterized our accelerated protocol by guiding the cells through differentiation with four different medias into MIXL1+ primitive streak cells with Activin A and CHIR for Wnt activation, intermediate mesoderm PAX8+ cells via increasing the CHIR concentration, nephron progenitors with FGF9 and Heparin for stabilization, and finally into differentiated podocytes with Activin A, BMP-7, VEGF, reduced CHIR, and retinoic acid. The podocyte morphology was characterized by scanning and transmission electron microscopy and by flow cytometry analysis for podocyte markers. To confirm cellular identity and niche localization, we performed cell recombination assays combining iPSC-podocytes with dissociated mouse embryonic kidney cells. Finally, to test iPSC-derived podocytes for the modeling of diabetic kidney disease, human podocytes were exposed to high glucose. RESULTS Podocyte markers were expressed at similar or higher levels for our accelerated protocol as compared to previously published protocols that require longer periods of tissue culture. We confirmed that the human podocytes derived from induced pluripotent stem cells in twelve days integrated into murine glomerular structures formed following seven days of culture of cellular recombinations. We found that the high glucose-treated human podocytes displayed actin rearrangement, increased cytotoxicity, and decreased viability. CONCLUSIONS We found that our accelerated 12-day method for the differentiation of podocytes from human-induced pluripotent stem cells yields podocytes with comparable marker expression to longer podocytes. We also demonstrated that podocytes created with this protocol have typical morphology by electron microscopy. The podocytes have utility for diabetes modeling as evidenced by lower viability and increased cytotoxicity when treated with high glucose. We found that multiple, diverse methods may be utilized to create iPSC-podocytes, but closely mimicking developmental cues shortened the time frame required for differentiation.
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Affiliation(s)
- Julie Bejoy
- grid.412807.80000 0004 1936 9916Division of Nephrology and Hypertension, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN 37232 USA
| | - Justin M. Farry
- grid.412807.80000 0004 1936 9916Division of Nephrology and Hypertension, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN 37232 USA ,grid.152326.10000 0001 2264 7217Department of Biomedical Engineering, Vanderbilt University, Nashville, TN 37232 USA
| | - Jennifer L. Peek
- grid.412807.80000 0004 1936 9916Division of Nephrology and Hypertension, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN 37232 USA
| | - Mariana C. Cabatu
- grid.412807.80000 0004 1936 9916Division of Nephrology and Hypertension, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN 37232 USA
| | - Felisha M. Williams
- grid.412807.80000 0004 1936 9916Division of Nephrology and Hypertension, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN 37232 USA
| | - Richard C. Welch
- grid.412807.80000 0004 1936 9916Division of Nephrology and Hypertension, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN 37232 USA
| | - Eddie S. Qian
- grid.412807.80000 0004 1936 9916Division of Nephrology and Hypertension, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN 37232 USA
| | - Lauren E. Woodard
- grid.412807.80000 0004 1936 9916Division of Nephrology and Hypertension, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN 37232 USA ,grid.152326.10000 0001 2264 7217Department of Biomedical Engineering, Vanderbilt University, Nashville, TN 37232 USA ,grid.452900.a0000 0004 0420 4633Department of Veterans Affairs, Tennessee Valley Healthcare System, Nashville, TN 37212 USA
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Kim EY, Dryer SE. TRPC6 Inactivation Reduces Albuminuria Induced by Protein Overload in Sprague Dawley Rats. Cells 2022; 11:1985. [PMID: 35805070 PMCID: PMC9265922 DOI: 10.3390/cells11131985] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Revised: 06/06/2022] [Accepted: 06/17/2022] [Indexed: 12/02/2022] Open
Abstract
Canonical transient receptor potential-6 (TRPC6) channels have been implicated in familial and acquired forms of focal and segmental glomerulosclerosis (FSGS), and in renal fibrosis following ureteral obstruction in mice. TRPC6 channels also appear to play a role in driving glomerular disease in aging and in autoimmune glomerulonephritis. In the present study, we examine the role of TRPC6 in the proteinuric state caused by prolonged albumin overload (AO) in Sprague Dawley rats induced by daily injections of exogenous albumin. This was assessed in rats with a global and constitutive inactivation of TRPC6 channels (Trpc6del/del rats) and in wild-type littermates (Trpc6wt/wt rats). AO for 14 and 28 days caused increased urine albumin excretion that was significantly attenuated in Trpc6del/del rats compared to Trpc6wt/wt controls. AO overload did not induce significant glomerulosclerosis or azotemia in either genotype. AO induced mild tubulointerstitial disease characterized by fibrosis, hypercellularity and increased expression of markers of fibrosis and inflammation. Those changes were equally severe in Trpc6wt/wt and Trpc6del/del rats. Immunoblot analysis of renal cortex indicated that AO increased the abundances of TRPC3 and TRPC6, and caused a nearly complete loss of TRPC5 in Trpc6wt/wt rats. The increase in TRPC3 and the loss of TRPC5 occurred to the same extent in Trpc6del/del rats. These data also suggest that TRPC6 plays a role in the normal function of the glomerular filtration barrier. However, whether TRPC6 inactivation protects the tubulointerstitial compartments in Sprague Dawley rats depends on the disease model examined.
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Affiliation(s)
- Eun Young Kim
- Department of Biology and Biochemistry, University of Houston, Houston, TX 77204, USA;
| | - Stuart E. Dryer
- Department of Biology and Biochemistry, University of Houston, Houston, TX 77204, USA;
- Department of Biomedical Sciences, Tilman J. Fertitta Family College of Medicine, University of Houston, Houston, TX 77204, USA
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Modes of podocyte death in diabetic kidney disease: an update. J Nephrol 2022; 35:1571-1584. [PMID: 35201595 DOI: 10.1007/s40620-022-01269-1] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2021] [Accepted: 02/01/2022] [Indexed: 02/06/2023]
Abstract
Diabetic kidney disease (DKD) accounts for a large proportion of end-stage renal diseases that require renal replacement therapies including dialysis and transplantation. Therefore, it is critical to understand the occurrence and development of DKD. Podocytes are mainly injured during the development of DKD, ultimately leading to their extensive death and loss. In turn, the injury and death of glomerular podocytes are also the main culprits of DKD. This review introduces the characteristics of podocytes and summarizes the modes of their death in DKD, including apoptosis, autophagy, mitotic catastrophe (MC), anoikis, necroptosis, and pyroptosis. Apoptosis is characterized by nuclear condensation and the formation of apoptotic bodies, and it exerts a different effect from autophagy in mediating DKD-induced podocyte loss. MC mediates a faulty mitotic process while anoikis separates podocytes from the basement membrane. Moreover, pyroptosis activates inflammatory factors to aggravate podocyte injuries whilst necroptosis drives signaling cascades, such as receptor-interacting protein kinases 1 and 3 and mixed lineage kinase domain-like, ultimately promoting the death of podocytes. In conclusion, a thorough knowledge of the modes of podocyte death in DKD can help us understand the development of DKD and lay the foundation for strategies in DKD disease therapy.
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Tagaya M, Kume S, Yasuda-Yamahara M, Kuwagata S, Yamahara K, Takeda N, Tanaka Y, Chin-Kanasaki M, Nakae Y, Yokoi H, Mukoyama M, Ishihara N, Nomura M, Araki SI, Maegawa H. Inhibition of mitochondrial fission protects podocytes from albumin-induced cell damage in diabetic kidney disease. Biochim Biophys Acta Mol Basis Dis 2022; 1868:166368. [DOI: 10.1016/j.bbadis.2022.166368] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Revised: 02/03/2022] [Accepted: 02/08/2022] [Indexed: 12/13/2022]
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Torres DD, Fontò G, Guastamacchia L, Santangelo L, Carbone V, Piscopo G, Spadaccino F, Ranieri E, Netti GS, Giordano M. Therapeutic Approach for Recurrent Focal Segmental Glomerulosclerosis in Pediatric Renal Transplant Recipients: A Single-Center Experience. Blood Purif 2022; 51:847-856. [DOI: 10.1159/000521311] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Accepted: 12/02/2021] [Indexed: 11/19/2022]
Abstract
<b><i>Introduction:</i></b> Recurrence of focal segmental glomerulosclerosis (FSGS) after kidney transplantation (KTx) develops in 40% of patients, leading to graft loss in half of cases. Extracorporeal apheretic treatments, combined with immunosuppressive drugs, seem to be the most promising therapies, but at now limited reports are available, mainly in pediatric patients. <b><i>Objective:</i></b> We aimed to assess the efficacy of immunoadsorption (IA) to treat recurrent FSGS in pediatric patients. <b><i>Methods:</i></b> We report a case series of 4 pediatric patients (aged 4–12 years) followed at our institution for early recurrent FSGS after KTx. FSGS recurrence was treated with early and intensive apheretic treatments IA. <b><i>Results:</i></b> After IA initiation, a partial remission (PR) of proteinuria at 24-month follow-up was achieved only in 1 patient. The others showed a mild reduction of nephrotic proteinuria, without PR, but gained a significant improvement in clinical signs of nephrotic syndrome (reduction of edema, increased serum albumin, and total protein levels). After a median follow-up of 38 (22–48) months, renal function was almost stable over time in all patients, except one who returned to hemodialysis after 22 months. No severe IA-related complications occurred. <b><i>Conclusions:</i></b> According to our clinical experience, IA revealed as a safe and effective therapy to treat patients with recurrent FSGS after KTx and it could maintain stable renal function in 75% of patients.
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Moriyama T, Hasegawa F, Miyabe Y, Akiyama K, Karasawa K, Uchida K, Nitta K. Intracellular trafficking pathway of albumin in glomerular epithelial cells. Biochem Biophys Res Commun 2021; 574:97-103. [PMID: 34450430 DOI: 10.1016/j.bbrc.2021.08.043] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Accepted: 08/18/2021] [Indexed: 10/20/2022]
Abstract
The intracellular trafficking pathway of albumin in podocytes remains controversial. We therefore analysed albumin endocytosis through caveolae, subsequent transcytosis, and exocytosis. In Western blot and immunofluorescence analysis in vitro, methyl-beta-cyclodextrin (MBCD) treatment significantly decreased the expression of caveolin-1 and albumin in cultured human podocytes after incubation with albumin; additionally, MBCD interfered with albumin endocytosis through caveolae in the experiment using Transwell plates. In the immunofluorescence analysis, albumin was incubated with cultured human podocytes, and colocalisation analysis with organelles and cytoskeletons in the podocytes showed that albumin particles colocalised with caveolin-1 and Fc-receptor but not clathrin in endocytosis, colocalised with actin cytoskeleton but not microtubules in transcytosis, and colocalised with early endosomes and lysosomes but not proteasome, endoplasmic reticulum, or Golgi apparatus. In the electron microscopic analysis of podocytes in nephrotic syndrome model mice, gold-labelled albumin was shown as endocytosis, transcytosis, and exocytosis with caveolae. These results indicate the intracellular trafficking of albumin through podocytes. Albumin enters through caveolae with the Fc-receptor, moves along actin, and reaches the early endosome, where some of them are sorted for lysosomal degradation, and others are directly transported outside the cells through exocytosis. This intracellular pathway may be a new aetiological hypothesis for albuminuria.
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Affiliation(s)
- Takahito Moriyama
- Department of Nephrology, Tokyo Women's Medical University, Tokyo, Japan.
| | - Fumio Hasegawa
- Department of Nephrology, Tokyo Women's Medical University, Tokyo, Japan.
| | - Yoei Miyabe
- Department of Nephrology, Tokyo Women's Medical University, Tokyo, Japan.
| | - Kenichi Akiyama
- Department of Nephrology, Tokyo Women's Medical University, Tokyo, Japan.
| | - Kazunori Karasawa
- Department of Nephrology, Tokyo Women's Medical University, Tokyo, Japan.
| | - Keiko Uchida
- Department of Nephrology, Tokyo Women's Medical University, Tokyo, Japan.
| | - Kosaku Nitta
- Department of Nephrology, Tokyo Women's Medical University, Tokyo, Japan.
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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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Larkin BP, Nguyen LT, Hou M, Glastras SJ, Chen H, Wang R, Pollock CA, Saad S. Novel Role of Gestational Hydralazine in Limiting Maternal and Dietary Obesity-Related Chronic Kidney Disease. Front Cell Dev Biol 2021; 9:705263. [PMID: 34485290 PMCID: PMC8416283 DOI: 10.3389/fcell.2021.705263] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Accepted: 07/30/2021] [Indexed: 01/16/2023] Open
Abstract
BACKGROUND Maternal obesity is a risk factor for chronic kidney disease (CKD) in offspring, underpinning the theory of the developmental origins of health and disease. DNA methylation has been implicated in the programming of adult chronic disease by maternal obesity, therefore, DNA demethylating agents may mitigate offspring risk of disease. In rodent models, low-dose hydralazine has previously been shown to reduce renal fibrosis via DNA demethylation. We used mouse models of maternal obesity and offspring obesity to determine whether administration of low-dose hydralazine during gestation can prevent fetal programming of CKD in offspring. METHODS Female C57BL/6 mice received high fat diet (HFD) or chow prior to mating, during gestation and lactation. During gestation, dams received subcutaneous hydralazine (5 mg/kg) or saline thrice-weekly. Male offspring weaned to HFD or chow, which continued until endpoint at 32 weeks. Biometric and metabolic parameters, renal global DNA methylation, renal functional and structural changes, and renal markers of fibrosis, inflammation and oxidative stress were assessed at endpoint. RESULTS Offspring exposed to maternal obesity or diet-induced obesity had significantly increased renal global DNA methylation, together with other adverse renal effects including albuminuria, glomerulosclerosis, renal fibrosis, and oxidative stress. Offspring exposed to gestational hydralazine had significantly reduced renal global DNA methylation. In obese offspring of obese mothers, gestational hydralazine significantly decreased albuminuria, glomerulosclerosis, and serum creatinine. Obese offspring of hydralazine-treated lean mothers displayed reduced markers of renal fibrosis and oxidative stress. CONCLUSION Gestational hydralazine decreased renal global DNA methylation and exerted renoprotective effects in offspring. This supports a potential therapeutic effect of hydralazine in preventing maternal obesity or dietary obesity-related CKD, through an epigenetic mechanism.
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Affiliation(s)
- Benjamin P. Larkin
- Renal Research Laboratory, Royal North Shore Hospital, Kolling Institute of Medical Research, University of Sydney, Sydney, NSW, Australia
| | - Long T. Nguyen
- Renal Research Laboratory, Royal North Shore Hospital, Kolling Institute of Medical Research, University of Sydney, Sydney, NSW, Australia
| | - Miao Hou
- Department of Cardiology, Children’s Hospital of Soochow University, Suzhou, China
| | - Sarah J. Glastras
- Renal Research Laboratory, Royal North Shore Hospital, Kolling Institute of Medical Research, University of Sydney, Sydney, NSW, Australia
- Department of Diabetes, Endocrinology and Metabolism, Royal North Shore Hospital, Sydney, NSW, Australia
| | - Hui Chen
- Faculty of Science, School of Life Sciences, University of Technology Sydney, Sydney, NSW, Australia
| | - Rosy Wang
- Renal Research Laboratory, Royal North Shore Hospital, Kolling Institute of Medical Research, University of Sydney, Sydney, NSW, Australia
| | - Carol A. Pollock
- Renal Research Laboratory, Royal North Shore Hospital, Kolling Institute of Medical Research, University of Sydney, Sydney, NSW, Australia
| | - Sonia Saad
- Renal Research Laboratory, Royal North Shore Hospital, Kolling Institute of Medical Research, University of Sydney, Sydney, NSW, Australia
- Faculty of Science, School of Life Sciences, University of Technology Sydney, Sydney, NSW, Australia
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12
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Figueroa SM, Araos P, Reyes J, Gravez B, Barrera-Chimal J, Amador CA. Oxidized Albumin as a Mediator of Kidney Disease. Antioxidants (Basel) 2021; 10:antiox10030404. [PMID: 33800425 PMCID: PMC8000637 DOI: 10.3390/antiox10030404] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Revised: 02/28/2021] [Accepted: 03/04/2021] [Indexed: 12/19/2022] Open
Abstract
Renal diseases are a global health concern, and nearly 24% of kidney disease patients are overweight or obese. Particularly, increased body mass index has been correlated with oxidative stress and urinary albumin excretion in kidney disease patients, also contributing to increased cardiovascular risk. Albumin is the main plasma protein and is able to partially cross the glomerular filtration barrier, being reabsorbed mainly by the proximal tubule through different mechanisms. However, it has been demonstrated that albumin suffers different posttranslational modifications, including oxidation, which appears to be tightly linked to kidney damage progression and is increased in obese patients. Plasma-oxidized albumin levels correlate with a decrease in estimated glomerular filtration rate and an increase in blood urea nitrogen in patients with chronic kidney disease. Moreover, oxidized albumin in kidney disease patients is independently correlated with higher plasma levels of transforming growth factor beta (TGF-β1), tumor necrosis factor (TNF-α), and interleukin (IL)-1β and IL-6. In addition, oxidized albumin exerts a direct effect on neutrophils by augmenting the levels of neutrophil gelatinase-associated lipocalin, a well-accepted biomarker for renal damage in patients and in different experimental settings. Moreover, it has been suggested that albumin oxidation occurs at early stages of chronic kidney disease, accelerating the patient requirements for dialytic treatment during disease progression. In this review, we summarize the evidence supporting the role of overweight- and obesity-induced oxidative stress as a critical factor for the progression of renal disease and cardiovascular morbimortality through albumin oxidation.
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Affiliation(s)
- Stefanny M. Figueroa
- Laboratory of Renal Physiopathology, Institute of Biomedical Sciences, Universidad Autónoma de Chile, Santiago 8910060, Chile; (S.M.F.); (P.A.); (J.R.); (B.G.)
| | - Patricio Araos
- Laboratory of Renal Physiopathology, Institute of Biomedical Sciences, Universidad Autónoma de Chile, Santiago 8910060, Chile; (S.M.F.); (P.A.); (J.R.); (B.G.)
| | - Javier Reyes
- Laboratory of Renal Physiopathology, Institute of Biomedical Sciences, Universidad Autónoma de Chile, Santiago 8910060, Chile; (S.M.F.); (P.A.); (J.R.); (B.G.)
| | - Basile Gravez
- Laboratory of Renal Physiopathology, Institute of Biomedical Sciences, Universidad Autónoma de Chile, Santiago 8910060, Chile; (S.M.F.); (P.A.); (J.R.); (B.G.)
| | - Jonatan Barrera-Chimal
- Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Mexico City 04510, Mexico;
- Laboratorio de Fisiología Cardiovascular y Trasplante Renal, Unidad de Investigación UNAM-INC, Instituto Nacional de Cardiología Ignacio Chávez, Mexico City 14080, Mexico
| | - Cristián A. Amador
- Laboratory of Renal Physiopathology, Institute of Biomedical Sciences, Universidad Autónoma de Chile, Santiago 8910060, Chile; (S.M.F.); (P.A.); (J.R.); (B.G.)
- Correspondence: ; Tel.: +56-22-303-6662
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13
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Li R, Xie Z, Zhang L, Huang Y, Ma J, Dong W, Li Z, Chen Y, Liang H, Wu Y, Zhao X, Wang W, Ye Z, Liu S, Shi W, Liang X. The effect of amiloride in decreasing albuminuria in patients with diabetic kidney diseases: a prospective, crossover, open-label study. Ren Fail 2021; 43:452-459. [PMID: 33657976 PMCID: PMC7935116 DOI: 10.1080/0886022x.2021.1892759] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
BACKGROUND Diabetic kidney diseases (DKD) were the leading cause of End-stage renal diseases worldwide. Albuminuria was a target for treatment in DKD and decreasing albuminuria was particularly important for improving its prognosis. However, there is still a lack of specific treatment for DKD. METHODS We conducted a prospective, crossover, open-label study to investigate the effect of amiloride in patients with DKD. Safety and efficacy were assessed by monitoring urine protein creatinine ratio(uPCR), urinary albumin creatinine ratio (uACR), blood pressure, weight, serum sodium, serum potassium, cholesterol, triglyceride, uric acid, serum soluble urokinase-type plasminogen activator receptor (suPAR) and urinary suPAR. Ten subjects were enrolled in the trial. RESULTS In this prospective, crossover, open-label design, amiloride could induce a significant decrease of uACR in DKD. The decrease of serum and urinary suPAR in the amiloride/hydrochlorothiazide (HCTZ) group was also significant compared with those patients using HCTZ as the control group. Correlation analysis showed that the levels of urinary suPAR were positively associated with uPCR and uACR. No significant difference in blood pressure, weight, serum sodium, serum potassium, cholesterol, triglyceride, uric acid was seen between the amiloride/HCTZ group and the control group. CONCLUSION In summary, among patients with DKD, amiloride could decrease albuminuria without severe side effects, which was accompanied by the significant decline of urinary suPAR.
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Affiliation(s)
- Ruizhao Li
- Division of Nephrology, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China
| | - Zhiyong Xie
- Division of Nephrology, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China.,The Second School of Clinical Medicine, Southern Medical University, Guangzhou, China
| | - Li Zhang
- Division of Nephrology, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China
| | - Ying Huang
- The Second School of Clinical Medicine, Southern Medical University, Guangzhou, China
| | - Jianchao Ma
- Division of Nephrology, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China
| | - Wei Dong
- Division of Nephrology, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China
| | - Zhilian Li
- Division of Nephrology, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China
| | - Yuanhan Chen
- Division of Nephrology, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China
| | - Huaban Liang
- Division of Nephrology, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China
| | - Yanhua Wu
- Division of Nephrology, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China
| | - Xingchen Zhao
- Division of Nephrology, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China
| | - Wenjian Wang
- Division of Nephrology, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China
| | - Zhiming Ye
- Division of Nephrology, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China
| | - Shuangxin Liu
- Division of Nephrology, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China
| | - Wei Shi
- Division of Nephrology, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China
| | - Xinling Liang
- Division of Nephrology, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China.,The Second School of Clinical Medicine, Southern Medical University, Guangzhou, China
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14
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Lesiak L, Zhou X, Fang Y, Zhao J, Beck JR, Stains CI. Imaging GPCR internalization using near-infrared Nebraska red-based reagents. Org Biomol Chem 2020; 18:2459-2467. [PMID: 32167123 DOI: 10.1039/d0ob00043d] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Internalization of G protein-coupled receptor (GPCRs) represents a nearly universal pathway for receptor downregulation. Imaging this process provides a means for the identification of pharmaceutical agents as well as potential ligands for orphan receptors. However, there is a need for the further development of near-infrared (NIR) probes capable of monitoring internalization in order to enable multiplexing with existing green fluorescent GPCR activity assays. Our laboratory has recently described a series of near-infrared (NIR) fluorophores in which a phosphinate functionality is inserted at the bridging position of the xanthene scaffold. These fluorophores, termed Nebraska Red (NR) dyes, provide attractive reagents for imaging protein localization. Herein, we disclose the development of NR-based HaloTag ligands for imaging membrane proteins on living cells. These new probes are utilized to image membrane pools of the human orexin type 2 receptor, an established target for the treatment of insomnia. We demonstrate the ability of fetal bovine serum (FBS) to noncovalently associate with a spirolactonized NR probe, enabling no-wash imaging with a 45-fold enhancement of fluorescence. Furthermore, we characterize the utility of NR-based HaloTag ligands for real-time monitoring of receptor internalization upon agonist stimulation. These new reagents enable potential multiplexing with existing GPCR activity assays in order to identify new modulators of GPCR activity as well as ligands for orphan receptors.
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Affiliation(s)
- Lauren Lesiak
- Department of Chemistry, University of Nebraska - Lincoln, Lincoln, NE 68588, USA.
| | - Xinqi Zhou
- Department of Chemistry, University of Nebraska - Lincoln, Lincoln, NE 68588, USA.
| | - Yuan Fang
- Department of Chemistry, University of Nebraska - Lincoln, Lincoln, NE 68588, USA. and Department of Chemistry, University of Virginia, Charlottesville, VA 22904, USA
| | - Jia Zhao
- Department of Chemistry, University of Nebraska - Lincoln, Lincoln, NE 68588, USA.
| | - Jon R Beck
- Department of Chemistry, University of Nebraska - Lincoln, Lincoln, NE 68588, USA.
| | - Cliff I Stains
- Department of Chemistry, University of Nebraska - Lincoln, Lincoln, NE 68588, USA. and Department of Chemistry, University of Virginia, Charlottesville, VA 22904, USA and Nebraska Center for Integrated Biomolecular Communication, University of Nebraska-Lincoln, Lincoln, NE 68588, USA and Cancer Genes and Molecular Regulation Program, Fred & Pamela Buffet Cancer Center, University of Nebraska Medical Center, Omaha, NE 68198, USA
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15
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Mendes RDS, Martins G, Oliveira MV, Rocha NN, Cruz FF, Antunes MA, Abreu SC, Silva AL, Takiya C, Pimentel-Coelho PM, Robba C, Mendez-Otero R, Pelosi P, Rocco PRM, Silva PL. Iso-Oncotic Albumin Mitigates Brain and Kidney Injury in Experimental Focal Ischemic Stroke. Front Neurol 2020; 11:1001. [PMID: 33013661 PMCID: PMC7494813 DOI: 10.3389/fneur.2020.01001] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Accepted: 07/30/2020] [Indexed: 12/14/2022] Open
Abstract
Background: There is widespread debate regarding the use of albumin in ischemic stroke. We tested the hypothesis that an iso-oncotic solution of albumin (5%), administered earlier after acute ischemic stroke (3 h), could provide neuroprotection without causing kidney damage, compared to a hyper-oncotic albumin (20%) and saline. Objective: To compare the effects of saline, iso-oncotic albumin, and hyper-oncotic albumin, all titrated to similar hemodynamic targets, on the brain and kidney. Methods: Ischemic stroke was induced in anesthetized male Wistar rats (n = 30; weight 437 ± 68 g) by thermocoagulation of pial blood vessels of the primary somatosensory, motor, and sensorimotor cortices. After 3 h, animals were anesthetized and randomly assigned (n = 8) to receive 0.9% NaCl (Saline), iso-oncotic albumin (5% ALB), and hyper-oncotic albumin (20% ALB), aiming to maintain hemodynamic stability (defined as distensibility index of inferior vena cava <25%, mean arterial pressure >80 mmHg). Rats were then ventilated using protective strategies for 2 h. Of these 30 animals, 6 were used as controls (focal ischemic stroke/no fluid). Results: The total fluid volume infused was higher in the Saline group than in the 5% ALB and 20% ALB groups (mean ± SD, 4.3 ± 1.6 vs. 2.7 ± 0.6 and 2.6 ± 0.5 mL, p = 0.03 and p = 0.02, respectively). The total albumin volume infused (g/kg) was higher in the 20% ALB group than in the 5% ALB group (1.4 ± 0.6 vs. 0.4 ± 0.2, p < 0.001). Saline increased neurodegeneration (Fluoro-Jade C staining), brain inflammation in the penumbra (higher tumor necrosis factor-alpha expression), and blood-brain barrier damage (lower gene expressions of claudin-1 and zona occludens-1) compared to both iso-oncotic and hyper-oncotic albumins, whereas it reduced the expression of brain-derived neurotrophic factor (a marker of neuroregeneration) compared only to iso-oncotic albumin. In the kidney, hyper-oncotic albumin led to greater damage as well as higher gene expressions of kidney injury molecule-1 and interleukin-6 than 5% ALB (p < 0.001). Conclusions: In this model of focal ischemic stroke, only iso-oncotic albumin had a protective effect against brain and kidney damage. Fluid therapy thus requires careful analysis of impact not only on the brain but also on the kidney.
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Affiliation(s)
- Renata de S Mendes
- Laboratory of Pulmonary Investigation, Institute of Biophysics Carlos Chagas Filho, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Gloria Martins
- Laboratory of Pulmonary Investigation, Institute of Biophysics Carlos Chagas Filho, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Milena V Oliveira
- Laboratory of Pulmonary Investigation, Institute of Biophysics Carlos Chagas Filho, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Nazareth N Rocha
- Laboratory of Pulmonary Investigation, Institute of Biophysics Carlos Chagas Filho, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Fernanda F Cruz
- Laboratory of Pulmonary Investigation, Institute of Biophysics Carlos Chagas Filho, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Mariana A Antunes
- Laboratory of Pulmonary Investigation, Institute of Biophysics Carlos Chagas Filho, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Soraia C Abreu
- Laboratory of Pulmonary Investigation, Institute of Biophysics Carlos Chagas Filho, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Adriana L Silva
- Laboratory of Pulmonary Investigation, Institute of Biophysics Carlos Chagas Filho, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Christina Takiya
- Laboratory of Imunophysiology, Institute of Biophysics Carlos Chagas Filho, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Pedro M Pimentel-Coelho
- Laboratory of Cellular and Molecular Neurobiology, Institute of Biophysics Carlos Chagas Filho, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Chiara Robba
- San Martino Policlinico Hospital, IRCCS for Oncology and Neurosciences, University of Genoa, Genoa, Italy
| | - Rosália Mendez-Otero
- Laboratory of Cellular and Molecular Neurobiology, Institute of Biophysics Carlos Chagas Filho, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Paolo Pelosi
- San Martino Policlinico Hospital, IRCCS for Oncology and Neurosciences, University of Genoa, Genoa, Italy.,Department of Surgical Sciences and Integrated Diagnostics (DISC), University of Genoa, Genoa, Italy
| | - Patricia R M Rocco
- Laboratory of Pulmonary Investigation, Institute of Biophysics Carlos Chagas Filho, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil.,Rio de Janeiro Network on Neuroinflammation, Carlos Chagas Filho Foundation for Supporting Research in the State of Rio de Janeiro (FAPERJ), Rio de Janeiro, Brazil
| | - Pedro L Silva
- Laboratory of Pulmonary Investigation, Institute of Biophysics Carlos Chagas Filho, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil.,Rio de Janeiro Network on Neuroinflammation, Carlos Chagas Filho Foundation for Supporting Research in the State of Rio de Janeiro (FAPERJ), Rio de Janeiro, Brazil
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16
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Blaine J, Dylewski J. Regulation of the Actin Cytoskeleton in Podocytes. Cells 2020; 9:cells9071700. [PMID: 32708597 PMCID: PMC7408282 DOI: 10.3390/cells9071700] [Citation(s) in RCA: 53] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Revised: 06/30/2020] [Accepted: 07/07/2020] [Indexed: 12/13/2022] Open
Abstract
Podocytes are an integral part of the glomerular filtration barrier, a structure that prevents filtration of large proteins and macromolecules into the urine. Podocyte function is dependent on actin cytoskeleton regulation within the foot processes, structures that link podocytes to the glomerular basement membrane. Actin cytoskeleton dynamics in podocyte foot processes are complex and regulated by multiple proteins and other factors. There are two key signal integration and structural hubs within foot processes that regulate the actin cytoskeleton: the slit diaphragm and focal adhesions. Both modulate actin filament extension as well as foot process mobility. No matter what the initial cause, the final common pathway of podocyte damage is dysregulation of the actin cytoskeleton leading to foot process retraction and proteinuria. Disruption of the actin cytoskeleton can be due to acquired causes or to genetic mutations in key actin regulatory and signaling proteins. Here, we describe the major structural and signaling components that regulate the actin cytoskeleton in podocytes as well as acquired and genetic causes of actin dysregulation.
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Affiliation(s)
- Judith Blaine
- Renal Division, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA;
| | - James Dylewski
- Renal Division, University of Colorado Anschutz Medical Campus and Denver Health Medical Center, Aurora, CO 80045, USA
- Correspondence: ; Tel.: +303-724-4841
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17
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Ren F, Zhang M, Zhang C, Sang H. Psoriasis-Like Inflammation Induced Renal Dysfunction through the TLR/NF- κB Signal Pathway. BIOMED RESEARCH INTERNATIONAL 2020; 2020:3535264. [PMID: 32090080 PMCID: PMC6996681 DOI: 10.1155/2020/3535264] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Accepted: 12/19/2019] [Indexed: 12/24/2022]
Abstract
Pathological studies have shown an association between psoriasis and renal injury (RI), but the mechanism between RI and psoriasis was still unclear. This paper was designed to investigate the relationship and mechanism between psoriasis-like inflammation and renal injury in BALB/C mice. Mice were topically smeared imiquimod followed by various analyses in skin lesions, urine protein, kidney/serum inflammatory cytokines, kidney function, podocyte membrane proteins, and toll-like receptors/nuclear factor kappa-b (TLR/NF-κB) pathway-associated proteins. Meanwhile, lipopolysaccharide (LPS) and dexamethasone (DEX) were intraperitoneally injected to promote and inhibit inflammation accompanied by imiquimod to elaborate the relevance between inflammatory levels and RI. In the model group, the Psoriasis Area and Severity Index (PASI) scores of scaly and erythema obviously increased (p < 0.01), creatinine and blood urea nitrogen significantly increased (p < 0.01), the positive area of hematoxylin-eosin (HE) and periodic acid-Schiff (PAS) staining in kidney increased (p < 0.01), malondialdehyde significantly increased with superoxide dismutase (SOD) decreased (p < 0.01), 24-hour urine protein increased and the expressions of podocin and CD2 associate protein (CD2AP) decreased (p < 0.01), and kidney/serum inflammatory factors (IL-17, IL-1β, IL-6, TNF-α, and IL-22) and TLR/NF-κB-related expression (TLR2, TLR4, MyD88, and NF-κBp65) all increased (p < 0.01). The RI was aggravated with the TLR/NF-κB related expression being upregulated by LPS (p < 0.05). On the contrary, the RI was alleviated by DEX (p < 0.05). Our data showed that psoriasis-like inflammation damaged the renal function via the TLR/NF-κB signal pathway. Inhibiting TLR/NF-κB-related protein expression may be effective for the treatment of RI caused by psoriasis.
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Affiliation(s)
- Fang Ren
- Department of Dermatology, Jinling Hospital, School of Medicine, Nanjing University, 305# Zhongshan East Road, Nanjing, Jiangsu 210003, China
| | - Min Zhang
- Department of Dermatology, The Affiliated Jiangning Hospital of Nanjing Medical University, 168# Gushan Road, Nanjing, Jiangsu 211100, China
| | - Caiyun Zhang
- Department of Dermatology, Jinling Hospital, School of Medicine, Nanjing University, 305# Zhongshan East Road, Nanjing, Jiangsu 210003, China
| | - Hong Sang
- Department of Dermatology, Jinling Hospital, School of Medicine, Nanjing University, 305# Zhongshan East Road, Nanjing, Jiangsu 210003, China
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18
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Usama SM, Park GK, Nomura S, Baek Y, Choi HS, Burgess K. Role of Albumin in Accumulation and Persistence of Tumor-Seeking Cyanine Dyes. Bioconjug Chem 2020; 31:248-259. [PMID: 31909595 DOI: 10.1021/acs.bioconjchem.9b00771] [Citation(s) in RCA: 60] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Some heptamethine cyanine dyes accumulate in solid tumors in vivo and persist there for several days. The reasons why they accumulate and persist in tumors were incompletely defined, but explanations based on uptake into cancer cells via organic anion transporting polypeptides (OATPs) have been widely discussed. All cyanine-based "tumor-seeking dyes" have a chloride centrally placed on the heptamethine bridge (a "meso-chloride"). We were intrigued and perplexed by the correlation between this particular functional group and tumor uptake, so the following study was designed. It features four dyes (1-Cl, 1-Ph, 5-Cl, and 5-Ph) with complementary properties. Dye 1-Cl is otherwise known as MHI-148, and 1-Ph is a close analog wherein the meso-chloride has been replaced by a phenyl group. Data presented here shows that both 1-Cl and 1-Ph form noncovalent adducts with albumin, but only 1-Cl can form a covalent one. Both dyes 5-Cl and 5-Ph have a methylene (CH2) unit replaced by a dimethylammonium functionality (N+Me2). Data presented here shows that both these dyes 5 do not form tight noncovalent adducts with albumin, and only 5-Cl can form a covalent one (though much more slowly than 1-Cl). In tissue culture experiments, uptake of dyes 1 is more impacted by the albumin in the media than by the pan-OATP uptake inhibitor (BSP) that has been used to connect uptake of tumor-seeking dyes in vivo with the OATPs. Uptake of 1-Cl in media containing fluorescein-labeled albumin gave a high degree of colocalization of intracellular fluorescence. No evidence was found for the involvement of OATPs in uptake of the dyes into cells in media containing albumin. In an in vivo tumor model, only the two dyes that can form albumin adducts (1-Cl and 5-Cl) gave intratumor fluorescence that persisted long enough to be clearly discerned over the background (∼4 h); this fluorescence was still observed at 48 h. Tumors could be imaged with a higher contrast if 5-Cl is used instead of 1-Cl, because 5-Cl is cleared more rapidly from healthy tissues. Overall, the evidence is consistent with in vitro and in vivo results and indicates that the two dyes in the test series that accumulate in tumors and persist there (1-Cl and 5-Cl, true tumor-seeking dyes) do so as covalent albumin adducts trapped in tumor tissue via uptake by some cancer cells and via the enhanced permeability and retention (EPR) effect.
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Affiliation(s)
- Syed Muhammad Usama
- Department of Chemistry , Texas A & M University , College Station , Texas 77842 , United States
| | - G Kate Park
- Gordon Center for Medical Imaging, Department of Radiology , Massachusetts General Hospital and Harvard Medical School , Boston , Massachusetts 02114 , United States
| | - Shinsuke Nomura
- Gordon Center for Medical Imaging, Department of Radiology , Massachusetts General Hospital and Harvard Medical School , Boston , Massachusetts 02114 , United States
| | - Yoonji Baek
- Gordon Center for Medical Imaging, Department of Radiology , Massachusetts General Hospital and Harvard Medical School , Boston , Massachusetts 02114 , United States
| | - Hak Soo Choi
- Gordon Center for Medical Imaging, Department of Radiology , Massachusetts General Hospital and Harvard Medical School , Boston , Massachusetts 02114 , United States
| | - Kevin Burgess
- Department of Chemistry , Texas A & M University , College Station , Texas 77842 , United States
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19
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Selc M, Razga F, Nemethova V, Mazancova P, Ursinyova M, Novotova M, Kopecka K, Gabelova A, Babelova A. Surface coating determines the inflammatory potential of magnetite nanoparticles in murine renal podocytes and mesangial cells. RSC Adv 2020; 10:23916-23929. [PMID: 35517346 PMCID: PMC9055089 DOI: 10.1039/d0ra03133j] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Accepted: 06/16/2020] [Indexed: 12/21/2022] Open
Abstract
Primary renal podocytes are more susceptible to MNPs exposure than primary renal mesangial cells.
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Affiliation(s)
- Michal Selc
- Department of Nanobiology
- Cancer Research Institute
- Biomedical Research Center
- Slovak Academy of Sciences
- 84505 Bratislava
| | - Filip Razga
- Faculty of Medicine
- Comenius University
- 81372 Bratislava
- Slovak Republic
- Selecta Biotech SE
| | - Veronika Nemethova
- Faculty of Medicine
- Comenius University
- 81372 Bratislava
- Slovak Republic
- Selecta Biotech SE
| | - Petra Mazancova
- Faculty of Medicine
- Comenius University
- 81372 Bratislava
- Slovak Republic
- Selecta Biotech SE
| | | | - Marta Novotova
- Institute of Experimental Endocrinology
- Biomedical Research Center
- Slovak Academy of Sciences
- 84505 Bratislava
- Slovak Republic
| | - Kristina Kopecka
- Department of Nanobiology
- Cancer Research Institute
- Biomedical Research Center
- Slovak Academy of Sciences
- 84505 Bratislava
| | - Alena Gabelova
- Department of Nanobiology
- Cancer Research Institute
- Biomedical Research Center
- Slovak Academy of Sciences
- 84505 Bratislava
| | - Andrea Babelova
- Department of Nanobiology
- Cancer Research Institute
- Biomedical Research Center
- Slovak Academy of Sciences
- 84505 Bratislava
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20
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Falcone S, Wisby L, Nicol T, Blease A, Starbuck B, Parker A, Sanderson J, Brown SDM, Scudamore CL, Pusey CD, Tam FWK, Potter PK. Modification of an aggressive model of Alport Syndrome reveals early differences in disease pathogenesis due to genetic background. Sci Rep 2019; 9:20398. [PMID: 31892712 PMCID: PMC6938516 DOI: 10.1038/s41598-019-56837-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Accepted: 12/05/2019] [Indexed: 12/13/2022] Open
Abstract
The link between mutations in collagen genes and the development of Alport Syndrome has been clearly established and a number of animal models, including knock-out mouse lines, have been developed that mirror disease observed in patients. However, it is clear from both patients and animal models that the progression of disease can vary greatly and can be modified genetically. We have identified a point mutation in Col4a4 in mice where disease is modified by strain background, providing further evidence of the genetic modification of disease symptoms. Our results indicate that C57BL/6J is a protective background and postpones end stage renal failure from 7 weeks, as seen on a C3H background, to several months. We have identified early differences in disease progression, including expression of podocyte-specific genes and podocyte morphology. In C57BL/6J mice podocyte effacement is delayed, prolonging normal renal function. The slower disease progression has allowed us to begin dissecting the pathogenesis of murine Alport Syndrome in detail. We find that there is evidence of differential gene expression during disease on the two genetic backgrounds, and that disease diverges by 4 weeks of age. We also show that an inflammatory response with increasing MCP-1 and KIM-1 levels precedes loss of renal function.
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Affiliation(s)
- Sara Falcone
- Mammalian Genetics Unit, Medical Research Council, Harwell science and innovation campus, Oxford, OX11 0RD, UK
| | - Laura Wisby
- Mammalian Genetics Unit, Medical Research Council, Harwell science and innovation campus, Oxford, OX11 0RD, UK
| | - Thomas Nicol
- Mammalian Genetics Unit, Medical Research Council, Harwell science and innovation campus, Oxford, OX11 0RD, UK
| | - Andrew Blease
- Mammalian Genetics Unit, Medical Research Council, Harwell science and innovation campus, Oxford, OX11 0RD, UK
| | - Becky Starbuck
- Mammalian Genetics Unit, Medical Research Council, Harwell science and innovation campus, Oxford, OX11 0RD, UK
| | - Andrew Parker
- Mammalian Genetics Unit, Medical Research Council, Harwell science and innovation campus, Oxford, OX11 0RD, UK
| | - Jeremy Sanderson
- Mammalian Genetics Unit, Medical Research Council, Harwell science and innovation campus, Oxford, OX11 0RD, UK
| | - Steve D M Brown
- Mammalian Genetics Unit, Medical Research Council, Harwell science and innovation campus, Oxford, OX11 0RD, UK
| | - Cheryl L Scudamore
- Mary Lyon Centre, Medical Research Council, Harwell science and innovation campus, Oxford, OX11 0RD, UK
| | - Charles D Pusey
- Renal and Vascular Inflammation Section, Department of Medicine, Imperial College, London, W12 0N, UK
| | - Frederick W K Tam
- Renal and Vascular Inflammation Section, Department of Medicine, Imperial College, London, W12 0N, UK
| | - Paul K Potter
- Renal and Vascular Inflammation Section, Department of Medicine, Imperial College, London, W12 0N, UK.
- Department of Biological and Medical Sciences, Faculty of Health and Life Sciences, Oxford Brookes University, Oxford, OX3 0BP, UK.
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21
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Candelier JJ, Lorenzo HK. Idiopathic nephrotic syndrome and serum permeability factors: a molecular jigsaw puzzle. Cell Tissue Res 2019; 379:231-243. [PMID: 31848752 DOI: 10.1007/s00441-019-03147-y] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2019] [Accepted: 11/19/2019] [Indexed: 12/14/2022]
Abstract
Nephrotic syndrome is traditionally defined using the triad of edema, hypoalbuminemia, and proteinuria, but this syndrome is very heterogeneous and difficult to clarify. Its idiopathic form (INS) is probably the most harmful and essentially comprises two entities: minimal change disease (MCD) and focal segmental glomerulosclerosis (FSGS). We will consider some hypotheses regarding the mechanisms underlying INS: (i) the presence of several glomerular permeability factors in the sera of patients that alter the morphology and function of podocytes leading to proteinuria, (ii) the putative role of immune cells. Thanks to recent data, our understanding of these disorders is evolving towards a more multifactorial origin. In this context, circulating factors may be associated according to sequential kinetic mechanisms or micro-environmental changes that need to be determined. In addition, the resulting proteinuria may trigger more proteinuria enhancing the glomerular destabilization.
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Affiliation(s)
- Jean-Jacques Candelier
- INSERM U1197, Hôpital Paul Brousse, 14 Avenue Paul Vaillant Couturier, 94800, Villejuif, France.,Université Paris-Saclay, Campus Universitaire d'Orsay, 91405, Orsay, France
| | - Hans-Kristian Lorenzo
- INSERM U1197, Hôpital Paul Brousse, 14 Avenue Paul Vaillant Couturier, 94800, Villejuif, France. .,Université Paris-Saclay, Campus Universitaire d'Orsay, 91405, Orsay, France. .,Service de Néphrologie, Hôpital Bicêtre, Faculté de Médecine Paris-Saclay, 94270, Le Kremlin-Bicêtre, France.
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22
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Tonsawan P, Dylewski J, Lewis L, Blaine J. Knockout of the neonatal Fc receptor in cultured podocytes alters IL-6 signaling and the actin cytoskeleton. Am J Physiol Cell Physiol 2019; 317:C1048-C1060. [PMID: 31553647 PMCID: PMC6879880 DOI: 10.1152/ajpcell.00235.2019] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Revised: 09/18/2019] [Accepted: 09/18/2019] [Indexed: 12/20/2022]
Abstract
The neonatal Fc receptor (FcRn) has been shown to be required for antigen presentation in dendritic cells, and global knockout of FcRn attenuates immune-mediated kidney disease. Podocytes express interleukin-6 (IL-6) receptor and produce IL-6 under proinflammatory conditions. Here we examined the role of FcRn in the IL-6-mediated inflammatory response in podocytes. We examined IL-6 production by ELISA and expression by qPCR in wild type (WT) and FcRn knockout (KO) podocytes after treatment with proinflammatory stimuli as well as IL-6-mediated signaling via the JAK/STAT pathway. We also examined podocyte motility in cultured WT and KO podocytes after a proinflammatory challenge. We found that FcRn KO podocytes produced minimal amount of IL-6 after treatment with albumin, IgG, or immune complexes whereas WT podocytes had a robust response. FcRn KO podocytes also had minimal expression of IL-6 compared with WT. By Western blotting, there was significantly less phosphorylated STAT3 in KO podocytes after treatment with IFNγ or immune complexes. In a scratch assay, FcRn KO podocytes showed increased motility comparted KO, suggesting a defect in actin dynamics. Cultured FcRn KO podocytes also demonstrated abnormal stress fibers compared with WT and the defect could be rescued by IL-6 treatment. This study shows that in podocytes, FcRn modulates the IL-6 mediated response to proinflammatory stimuli and regulates podocytes actin structure, motility and synaptopodin expression.
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Affiliation(s)
- Pantipa Tonsawan
- Division of Renal Disease and Hypertension, University of Colorado School of Medicine, Aurora, Colorado
- Division of Nephrology, Department of Medicine, Khon Kaen University, Khon Kaen, Thailand
| | - James Dylewski
- Division of Renal Disease and Hypertension, University of Colorado School of Medicine, Aurora, Colorado
- Department of Nephrology, Denver Health Medical Center, Denver, Colorado
| | - Linda Lewis
- Division of Renal Disease and Hypertension, University of Colorado School of Medicine, Aurora, Colorado
| | - Judith Blaine
- Division of Renal Disease and Hypertension, University of Colorado School of Medicine, Aurora, Colorado
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23
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An update on LDL apheresis for nephrotic syndrome. Pediatr Nephrol 2019; 34:1655-1669. [PMID: 30218191 DOI: 10.1007/s00467-018-4061-9] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/08/2018] [Revised: 08/13/2018] [Accepted: 08/16/2018] [Indexed: 01/03/2023]
Abstract
Low-density lipoprotein (LDL) apheresis has been used increasingly in clinical practice for the treatment of renal diseases with nephrotic syndrome (NS), specifically focal segmental glomerulosclerosis (FSGS). Persistent hyperlipidemia for prolonged periods is nephrotoxic and leads to chronic progressive glomerular and tubulointerstitial injury. Effective management of hyperlipidemia with HMG-CoA reductase inhibitors or LDL apheresis in drug-resistant NS patients may prevent the progression of renal disease and, in some patients, resolution of NS symptoms. Available literature reveals beneficial effects of LDL apheresis for NS refractory to drug therapy. Here we update on the current understanding of lipid nephrotoxicity and application of LDL apheresis to prevent progression of renal diseases.
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24
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Lagies S, Pichler R, Bork T, Kaminski MM, Troendle K, Zimmermann S, Huber TB, Walz G, Lienkamp SS, Kammerer B. Impact of Diabetic Stress Conditions on Renal Cell Metabolome. Cells 2019; 8:cells8101141. [PMID: 31554337 PMCID: PMC6829414 DOI: 10.3390/cells8101141] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2019] [Revised: 09/12/2019] [Accepted: 09/19/2019] [Indexed: 01/10/2023] Open
Abstract
Diabetic kidney disease is a major complication in diabetes mellitus, and the most common reason for end-stage renal disease. Patients suffering from diabetes mellitus encounter glomerular damage by basement membrane thickening, and develop albuminuria. Subsequently, albuminuria can deteriorate the tubular function and impair the renal outcome. The impact of diabetic stress conditions on the metabolome was investigated by untargeted gas chromatography–mass spectrometry (GC-MS) analyses. The results were validated by qPCR analyses. In total, four cell lines were tested, representing the glomerulus, proximal nephron tubule, and collecting duct. Both murine and human cell lines were used. In podocytes, proximal tubular and collecting duct cells, high glucose concentrations led to global metabolic alterations in amino acid metabolism and the polyol pathway. Albumin overload led to the further activation of the latter pathway in human proximal tubular cells. In the proximal tubular cells, aldo-keto reductase was concordantly increased by glucose, and partially increased by albumin overload. Here, the combinatorial impact of two stressful agents in diabetes on the metabolome of kidney cells was investigated, revealing effects of glucose and albumin on polyol metabolism in human proximal tubular cells. This study shows the importance of including highly concentrated albumin in in vitro studies for mimicking diabetic kidney disease.
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Affiliation(s)
- Simon Lagies
- Center for Biological Systems Analysis (ZBSA), Albert-Ludwigs-University Freiburg, Habsburgerstr. 49, 79104 Freiburg, Germany
- Spemann Graduate School of Biology and Medicine (SGBM), University of Freiburg, 79104 Freiburg, Germany
- Faculty of Biology, University of Freiburg, 79104 Freiburg, Germany
| | - Roman Pichler
- Department of Medicine, Renal Division, Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg, 79106 Freiburg, Germany
| | - Tillmann Bork
- Department of Medicine, Renal Division, Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg, 79106 Freiburg, Germany
| | - Michael M Kaminski
- Department of Medicine, Renal Division, Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg, 79106 Freiburg, Germany
| | - Kevin Troendle
- Laboratory for MEMS Applications, IMTEK-Department of Microsystems Engineering, University of Freiburg, 79110 Freiburg, Germany
| | - Stefan Zimmermann
- Laboratory for MEMS Applications, IMTEK-Department of Microsystems Engineering, University of Freiburg, 79110 Freiburg, Germany
| | - Tobias B Huber
- III. Department of Medicine, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
| | - Gerd Walz
- Department of Medicine, Renal Division, Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg, 79106 Freiburg, Germany
- BIOSS Centre of Biological Signalling Studies, University of Freiburg, 79104 Freiburg, Germany
| | - Soeren S Lienkamp
- Department of Medicine, Renal Division, Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg, 79106 Freiburg, Germany
- Institute of Anatomy, University of Zurich, 8057 Zurich, Switzerland
| | - Bernd Kammerer
- Center for Biological Systems Analysis (ZBSA), Albert-Ludwigs-University Freiburg, Habsburgerstr. 49, 79104 Freiburg, Germany.
- BIOSS Centre of Biological Signalling Studies, University of Freiburg, 79104 Freiburg, Germany.
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25
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Mendes RDS, Oliveira MV, Padilha GA, Rocha NN, Santos CL, Maia LA, Fernandes MVDS, Cruz FF, Olsen PC, Capelozzi VL, de Abreu MG, Pelosi P, Rocco PRM, Silva PL. Effects of crystalloid, hyper-oncotic albumin, and iso-oncotic albumin on lung and kidney damage in experimental acute lung injury. Respir Res 2019; 20:155. [PMID: 31311539 PMCID: PMC6636113 DOI: 10.1186/s12931-019-1115-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2019] [Accepted: 06/28/2019] [Indexed: 12/19/2022] Open
Abstract
BACKGROUND Conflicting data have reported beneficial effects of crystalloids, hyper-oncotic albumin (20%ALB), and iso-oncotic albumin (5%ALB) in critically ill patients. Although hyper-oncotic albumin may minimize lung injury, recent studies have shown that human albumin may lead to kidney damage proportional to albumin concentration. In this context, we compared the effects of Ringer's lactate (RL), 20%ALB, and 5%ALB, all titrated according to similar hemodynamic goals, on pulmonary function, lung and kidney histology, and molecular biology in experimental acute lung injury (ALI). METHODS Male Wistar rats received Escherichia coli lipopolysaccharide intratracheally (n = 24) to induce ALI. After 24 h, animals were anesthetized and randomly assigned to receive RL, 20%ALB, or 5%ALB (n = 6/group) to maintain hemodynamic stability (distensibility index of inferior vena cava < 25%, mean arterial pressure > 65 mmHg). Rats were then mechanically ventilated for 6 h. Six animals, which received neither ventilation nor fluids (NV), were used for molecular biology analyses. RESULTS The total fluid volume infused was higher in RL compared to 5%ALB and 20%ALB (median [interquartile range], 10.8[8.2-33.2] vs. 4.8[3.6-7.7] and 4.3[3.9-6.6] mL, respectively; p = 0.02 and p = 0.003). B-line counts on lung ultrasound (p < 0.0001 and p = 0.0002) and serum lactate levels (p = 0.01 and p = 0.01) were higher in RL than 5%ALB and 20%ALB. Diffuse alveolar damage score was lower in 5%ALB (10.5[8.5-12]) and 20%ALB (10.5[8.5-14]) than RL (16.5[12.5-20.5]) (p < 0.05 and p = 0.03, respectively), while acute kidney injury score was lower in 5%ALB (9.5[6.5-10]) than 20%ALB (18[15-28.5], p = 0.0006) and RL (16 [15-19], p = 0.04). In lung tissue, mRNA expression of interleukin (IL)-6 was higher in RL (59.1[10.4-129.3]) than in 5%ALB (27.0[7.8-49.7], p = 0.04) or 20%ALB (3.7[7.8-49.7], p = 0.03), and IL-6 protein levels were higher in RL than 5%ALB and 20%ALB (p = 0.026 and p = 0.021, respectively). In kidney tissue, mRNA expression and protein levels of kidney injury molecule (KIM)-1 were lower in 5%ALB than RL and 20%ALB, while nephronectin expression increased (p = 0.01 and p = 0.01), respectively. CONCLUSIONS In a rat model of ALI, both iso-oncotic and hyper-oncotic albumin solutions were associated with less lung injury compared to Ringer's lactate. However, hyper-oncotic albumin resulted in greater kidney damage than iso-oncotic albumin. This experimental study is a step towards future clinical designs.
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Affiliation(s)
- Renata de S Mendes
- Laboratory of Pulmonary Investigation, Carlos Chagas Filho Biophysics Institute, Federal University of Rio de Janeiro, Centro de Ciências da Saúde, Avenida Carlos Chagas Filho, s/n, Bloco G-014, Ilha do Fundão, Rio de Janeiro, RJ, 21941-902, Brazil
| | - Milena V Oliveira
- Laboratory of Pulmonary Investigation, Carlos Chagas Filho Biophysics Institute, Federal University of Rio de Janeiro, Centro de Ciências da Saúde, Avenida Carlos Chagas Filho, s/n, Bloco G-014, Ilha do Fundão, Rio de Janeiro, RJ, 21941-902, Brazil
| | - Gisele A Padilha
- Laboratory of Pulmonary Investigation, Carlos Chagas Filho Biophysics Institute, Federal University of Rio de Janeiro, Centro de Ciências da Saúde, Avenida Carlos Chagas Filho, s/n, Bloco G-014, Ilha do Fundão, Rio de Janeiro, RJ, 21941-902, Brazil
| | - Nazareth N Rocha
- Laboratory of Pulmonary Investigation, Carlos Chagas Filho Biophysics Institute, Federal University of Rio de Janeiro, Centro de Ciências da Saúde, Avenida Carlos Chagas Filho, s/n, Bloco G-014, Ilha do Fundão, Rio de Janeiro, RJ, 21941-902, Brazil.,Department of Physiology and Pharmacology, Biomedical Institute, Fluminense Federal University, Rio de Janeiro, Brazil
| | - Cintia L Santos
- Laboratory of Pulmonary Investigation, Carlos Chagas Filho Biophysics Institute, Federal University of Rio de Janeiro, Centro de Ciências da Saúde, Avenida Carlos Chagas Filho, s/n, Bloco G-014, Ilha do Fundão, Rio de Janeiro, RJ, 21941-902, Brazil
| | - Ligia A Maia
- Laboratory of Pulmonary Investigation, Carlos Chagas Filho Biophysics Institute, Federal University of Rio de Janeiro, Centro de Ciências da Saúde, Avenida Carlos Chagas Filho, s/n, Bloco G-014, Ilha do Fundão, Rio de Janeiro, RJ, 21941-902, Brazil
| | - Marcos V de S Fernandes
- Laboratory of Pulmonary Investigation, Carlos Chagas Filho Biophysics Institute, Federal University of Rio de Janeiro, Centro de Ciências da Saúde, Avenida Carlos Chagas Filho, s/n, Bloco G-014, Ilha do Fundão, Rio de Janeiro, RJ, 21941-902, Brazil
| | - Fernanda F Cruz
- Laboratory of Pulmonary Investigation, Carlos Chagas Filho Biophysics Institute, Federal University of Rio de Janeiro, Centro de Ciências da Saúde, Avenida Carlos Chagas Filho, s/n, Bloco G-014, Ilha do Fundão, Rio de Janeiro, RJ, 21941-902, Brazil
| | - Priscilla C Olsen
- Laboratory of Bacteriology and Clinical Immunology, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Vera L Capelozzi
- Department of Pathology, University of Sao Paulo, Sao Paulo, Brazil
| | - Marcelo Gama de Abreu
- Pulmonary Engineering Group, Department of Anesthesiology and Intensive Care Therapy, University Hospital Dresden, Technische Universität Dresden, Dresden, Germany
| | - Paolo Pelosi
- Department of Surgical Sciences and Integrated Diagnostics (DISC), University of Genoa, Genoa, Italy.,IRCCS San Martino Policlinico Hospital, Genoa, Italy
| | - Patricia R M Rocco
- Laboratory of Pulmonary Investigation, Carlos Chagas Filho Biophysics Institute, Federal University of Rio de Janeiro, Centro de Ciências da Saúde, Avenida Carlos Chagas Filho, s/n, Bloco G-014, Ilha do Fundão, Rio de Janeiro, RJ, 21941-902, Brazil
| | - Pedro L Silva
- Laboratory of Pulmonary Investigation, Carlos Chagas Filho Biophysics Institute, Federal University of Rio de Janeiro, Centro de Ciências da Saúde, Avenida Carlos Chagas Filho, s/n, Bloco G-014, Ilha do Fundão, Rio de Janeiro, RJ, 21941-902, Brazil.
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26
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Differential trafficking of albumin and IgG facilitated by the neonatal Fc receptor in podocytes in vitro and in vivo. PLoS One 2019; 14:e0209732. [PMID: 30811433 PMCID: PMC6392300 DOI: 10.1371/journal.pone.0209732] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Accepted: 02/12/2019] [Indexed: 12/26/2022] Open
Abstract
Proteinuria is strongly associated with kidney disease progression but the mechanisms underlying podocyte handling of serum proteins such as albumin and IgG remain to be elucidated. We have previously shown that albumin and IgG are transcytosed by podocytes in vitro. In other epithelial cells, the neonatal Fc receptor (FcRn) is required to salvage albumin and IgG from the degradative pathway thereby allowing these proteins to be transcytosed or recycled. Here we directly examine the role of FcRn in albumin and IgG trafficking in podocytes by studying handling of these proteins in FcRn knockout (KO) podocytes in vitro and in a podocyte-specific FcRn knockout mice in vivo. In vitro, we find that knockout of FcRn leads to IgG accumulation in podocytes but does not alter albumin trafficking. Similarly, in vivo, podocyte-specific knockout of FcRn does not result in albumin accumulation in podocytes in vivo as measured by mean albumin fluorescence intensity whereas these mice demonstrate significant intraglomerular accumulation of IgG over time. In addition we find that podocyte-specific FcRn KO mice demonstrate mesangial expansion as they age and activation of mesangial cells as demonstrated by increased expression of α-smooth muscle actin. Taken together, these results suggest that trafficking pathways for albumin and IgG differ in podocytes and that sustained disruption of trafficking of plasma proteins alters glomerular structure.
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27
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Intracellular albumin overload elicits endoplasmic reticulum stress and PKC-delta/p38 MAPK pathway activation to induce podocyte apoptosis. Sci Rep 2018; 8:18012. [PMID: 30573754 PMCID: PMC6301950 DOI: 10.1038/s41598-018-36933-9] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2018] [Accepted: 11/29/2018] [Indexed: 12/22/2022] Open
Abstract
Podocyte injury is closely related to proteinuria and the progression of chronic kidney disease (CKD). Currently, there is no conclusive understanding about the mechanisms involved in albumin overload and podocyte apoptosis response. In this study, we sought to explore the ways by which intracellular albumin can mediate podocyte apoptosis. Here, immortalized mouse podocytes were treated with bovine serum albumin (BSA) at different times and concentrations, in the presence or absence of SB203580 (0.1 µM, inhibitor of mitogen-activated-protein kinase – p38MAPK). Using immunofluorescence images, flow cytometry and immunoblotting, we observed a time-dependent intracellular accumulation of fluorescent albumin-FITC-BSA, followed by concentration-and time-dependent effect of intracellular albumin overload on podocyte apoptosis, which was mediated by increased expression of the chaperone glucose-regulated-protein 78 (GRP 78) and phosphorylated inositol-requiring enzyme 1 alpha (pIRE1-α), as well as protein kinase C delta (PKC-δ), p38MAPK and cleaved caspase 12 expression. SB203580 prevented the cleavage of caspase 12 and the albumin-mediated podocyte apoptosis. These results suggest that intracellular albumin overload is associated with endoplasmic reticulum (ER) stress and upregulation of PKC-δ/p38MAPK/caspase 12 pathway, which may be a target for future therapeutic of albumin-induced podocyte apoptosis.
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28
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Abstract
Molecular entities that localize in tumor tissue are clinically important for targeted delivery of diagnostic, imaging, and therapeutic reagents. Often these targeting entities are designed for specific receptors (e.g., EGFR or integrin receptors). However, there is a subset of cyanine-7 dyes that apparently localize in every type of solid tumor tissue (at least, no exceptions have been reported so far), and they persist there for several days. Consequently, these dyes can be used for near-IR optical imaging of tumors in animal studies, they can be conjugated with cytotoxic species to give experimental theranostics, and there is potential for expanding their use into the development of clinically useful derivatives. Data presented in the literature and in this work indicate that the half-lives of these compounds in serum at 37 °C is on the order of minutes to a few hours, so what accounts for the persistent fluorescence of these dyes in tumor tissue over periods of several days? Literature, solely based on tissue culture experiments featuring a particular receptor blocker, indicates that uptake of these dyes is mediated by the organic anion transporter proteins (OATPs). Data presented in this paper agrees with that conclusion for short-term uptake, but significantly expands understanding of the likely reasons for long-term uptake and persistent tumor localization in vivo.
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Affiliation(s)
- Syed Muhammad Usama
- Department of Chemistry Texas A&M University , Box 30012, College Station , Texas 77842 , United States
| | - Chen-Ming Lin
- Department of Chemistry Texas A&M University , Box 30012, College Station , Texas 77842 , United States
| | - Kevin Burgess
- Department of Chemistry Texas A&M University , Box 30012, College Station , Texas 77842 , United States
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29
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Caster DJ, Korte EA, Tan M, Barati MT, Tandon S, Creed TM, Salant DJ, Hata JL, Epstein PN, Huang H, Powell DW, McLeish KR. Neutrophil exocytosis induces podocyte cytoskeletal reorganization and proteinuria in experimental glomerulonephritis. Am J Physiol Renal Physiol 2018; 315:F595-F606. [PMID: 29790391 DOI: 10.1152/ajprenal.00039.2018] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Acute glomerulonephritis is characterized by rapid glomerular neutrophil recruitment, proteinuria, and glomerular hypercellularity. The current study tested the hypothesis that the release of neutrophil granule contents plays a role in both the loss of filtration barrier leading to proteinuria and the increase in glomerular cells. Inhibition of neutrophil exocytosis with a peptide inhibitor prevented proteinuria and attenuated podocyte and endothelial cell injury but had no effect on glomerular hypercellularity in an experimental acute glomerulonephritis model in mice. Cultivation of podocytes with neutrophil granule contents disrupted cytoskeletal organization, an in vitro model for podocyte effacement and loss of filtration barrier. Activated, cultured podocytes released cytokines that stimulated neutrophil chemotaxis, primed respiratory burst activity, and stimulated neutrophil exocytosis. We conclude that crosstalk between podocytes and neutrophils contributes to disruption of the glomerular filtration barrier in acute glomerulonephritis. Neutrophil granule products induce podocyte injury but do not participate in the proliferative response of intrinsic glomerular cells.
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Affiliation(s)
- Dawn J Caster
- Department of Medicine, University of Louisville , Louisville, Kentucky.,Robley Rex Veterans Affairs Medical Center , Louisville, Kentucky
| | - Erik A Korte
- Department of Biochemistry and Molecular Genetics, University of Louisville , Louisville, Kentucky
| | - Min Tan
- Department of Medicine, University of Louisville , Louisville, Kentucky
| | - Michelle T Barati
- Department of Medicine, University of Louisville , Louisville, Kentucky
| | - Shweta Tandon
- Department of Medicine, University of Louisville , Louisville, Kentucky
| | - T Michael Creed
- Department of Medicine, University of Louisville , Louisville, Kentucky
| | - David J Salant
- Department of Medicine, Boston University School of Medicine , Boston, Massachusetts
| | - Jessica L Hata
- Pathology Department, Norton Children's Hospital , Louisville, Kentucky
| | - Paul N Epstein
- Pediatric Research Institute in the Department of Pediatrics, University of Louisville , Louisville, Kentucky
| | - Hui Huang
- Pediatric Research Institute in the Department of Pediatrics, University of Louisville , Louisville, Kentucky.,Department of Endocrinology, Metabolism, and Genetics, Jiangxi Provincial Children's Hospital , Nanchang , China
| | - David W Powell
- Department of Medicine, University of Louisville , Louisville, Kentucky
| | - Kenneth R McLeish
- Department of Medicine, University of Louisville , Louisville, Kentucky.,Robley Rex Veterans Affairs Medical Center , Louisville, Kentucky
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30
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Abstract
Kidney cell death plays a key role in the progression of life-threatening renal diseases, such as acute kidney injury and chronic kidney disease. Injured and dying epithelial and endothelial cells take part in complex communication with the innate immune system, which drives the progression of cell death and the decrease in renal function. To improve our understanding of kidney cell death dynamics and its impact on renal disease, a study approach is needed that facilitates the visualization of renal function and morphology in real time. Intravital multiphoton microscopy of the kidney has been used for more than a decade and made substantial contributions to our understanding of kidney physiology and pathophysiology. It is a unique tool that relates renal structure and function in a time- and spatial-dependent manner. Basic renal function, such as microvascular blood flow regulation and glomerular filtration, can be determined in real time and homeostatic alterations, which are linked inevitably to cell death and can be depicted down to the subcellular level. This review provides an overview of the available techniques to study kidney dysfunction and inflammation in terms of cell death in vivo, and addresses how this novel approach can be used to improve our understanding of cell death dynamics in renal disease.
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31
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Naudin C, Smith B, Bond DR, Dun MD, Scott RJ, Ashman LK, Weidenhofer J, Roselli S. Characterization of the early molecular changes in the glomeruli of Cd151 -/- mice highlights induction of mindin and MMP-10. Sci Rep 2017; 7:15987. [PMID: 29167507 PMCID: PMC5700190 DOI: 10.1038/s41598-017-15993-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2017] [Accepted: 10/26/2017] [Indexed: 01/06/2023] Open
Abstract
In humans and FVB/N mice, loss of functional tetraspanin CD151 is associated with glomerular disease characterised by early onset proteinuria and ultrastructural thickening and splitting of the glomerular basement membrane (GBM). To gain insight into the molecular mechanisms associated with disease development, we characterised the glomerular gene expression profile at an early stage of disease progression in FVB/N Cd151 -/- mice compared to Cd151 +/+ controls. This study identified 72 up-regulated and 183 down-regulated genes in FVB/N Cd151 -/- compared to Cd151 +/+ glomeruli (p < 0.05). Further analysis highlighted induction of the matrix metalloprotease MMP-10 and the extracellular matrix protein mindin (encoded by Spon2) in the diseased FVB/N Cd151 -/- GBM that did not occur in the C57BL/6 diseased-resistant strain. Interestingly, mindin was also detected in urinary samples of FVB/N Cd151 -/- mice, underlining its potential value as a biomarker for glomerular diseases associated with GBM alterations. Gene set enrichment and pathway analysis of the microarray dataset showed enrichment in axon guidance and actin cytoskeleton signalling pathways as well as activation of inflammatory pathways. Given the known function of mindin, its early expression in the diseased GBM could represent a trigger of both further podocyte cytoskeletal changes and inflammation, thereby playing a key role in the mechanisms of disease progression.
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Affiliation(s)
- Crystal Naudin
- School of Biomedical Sciences and Pharmacy, Faculty of Health and Medicine, University of Newcastle, Newcastle, New South Wales, Australia.,Hunter Medical Research Institute, New Lambton, New South Wales, Australia.,Emory University, Atlanta, Georgia, USA
| | - Brian Smith
- School of Mathematics and Physical Sciences, University of Newcastle, Newcastle, New South Wales, Australia
| | - Danielle R Bond
- School of Biomedical Sciences and Pharmacy, Faculty of Health and Medicine, University of Newcastle, Newcastle, New South Wales, Australia.,Hunter Medical Research Institute, New Lambton, New South Wales, Australia
| | - Matthew D Dun
- School of Biomedical Sciences and Pharmacy, Faculty of Health and Medicine, University of Newcastle, Newcastle, New South Wales, Australia.,Hunter Medical Research Institute, New Lambton, New South Wales, Australia
| | - Rodney J Scott
- School of Biomedical Sciences and Pharmacy, Faculty of Health and Medicine, University of Newcastle, Newcastle, New South Wales, Australia.,Hunter Medical Research Institute, New Lambton, New South Wales, Australia.,Hunter Area Pathology Service, John Hunter Hospital, New Lambton, New South Wales, Australia
| | - Leonie K Ashman
- School of Biomedical Sciences and Pharmacy, Faculty of Health and Medicine, University of Newcastle, Newcastle, New South Wales, Australia.,Hunter Medical Research Institute, New Lambton, New South Wales, Australia
| | - Judith Weidenhofer
- School of Biomedical Sciences and Pharmacy, Faculty of Health and Medicine, University of Newcastle, Newcastle, New South Wales, Australia.,Hunter Medical Research Institute, New Lambton, New South Wales, Australia
| | - Séverine Roselli
- School of Biomedical Sciences and Pharmacy, Faculty of Health and Medicine, University of Newcastle, Newcastle, New South Wales, Australia. .,Hunter Medical Research Institute, New Lambton, New South Wales, Australia.
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32
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Gianesello L, Priante G, Ceol M, Radu CM, Saleem MA, Simioni P, Terrin L, Anglani F, Del Prete D. Albumin uptake in human podocytes: a possible role for the cubilin-amnionless (CUBAM) complex. Sci Rep 2017; 7:13705. [PMID: 29057905 PMCID: PMC5651885 DOI: 10.1038/s41598-017-13789-z] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2017] [Accepted: 10/02/2017] [Indexed: 12/23/2022] Open
Abstract
Albumin re-uptake is a receptor-mediated pathway located in renal proximal tubuli. There is increasing evidence of glomerular protein handling by podocytes, but little is known about the mechanism behind this process. In this study, we found that human podocytes in vitro are committed to internalizing albumin through a receptor-mediated mechanism even after exposure to low doses of albumin. We show that these cells express cubilin, megalin, ClC-5, amnionless and Dab2, which are partners in the tubular machinery. Exposing human podocytes to albumin overload prompted an increase in CUBILIN, AMNIONLESS and CLCN5 gene expression. Inhibiting cubilin led to a reduction in albumin uptake, highlighting its importance in this mechanism. We demonstrated that human podocytes are committed to performing endocytosis via a receptor-mediated mechanism even in the presence of low doses of albumin. We also disclosed that protein overload first acts on the expression of the cubilin-amnionless (CUBAM) complex in these cells, then involves the ClC-5 channel, providing the first evidence for a possible role of the CUBAM complex in albumin endocytosis in human podocytes.
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Affiliation(s)
- Lisa Gianesello
- Clinical Nephrology, Department of Medicine - DIMED, University of Padua, 35129, Padua, Italy
| | - Giovanna Priante
- Clinical Nephrology, Department of Medicine - DIMED, University of Padua, 35129, Padua, Italy
| | - Monica Ceol
- Clinical Nephrology, Department of Medicine - DIMED, University of Padua, 35129, Padua, Italy
| | - Claudia M Radu
- Thrombotic and Hemorrhagic Diseases Unit, Department of Medicine - DIMED, University of Padua, 35129, Padua, Italy
| | - Moin A Saleem
- Academic and Children's Renal Unit, Dorothy Hodgkin Building, BS8 1TH, Bristol, United Kingdom
| | - Paolo Simioni
- Thrombotic and Hemorrhagic Diseases Unit, Department of Medicine - DIMED, University of Padua, 35129, Padua, Italy
| | - Liliana Terrin
- Clinical Nephrology, Department of Medicine - DIMED, University of Padua, 35129, Padua, Italy
| | - Franca Anglani
- Clinical Nephrology, Department of Medicine - DIMED, University of Padua, 35129, Padua, Italy
| | - Dorella Del Prete
- Clinical Nephrology, Department of Medicine - DIMED, University of Padua, 35129, Padua, Italy.
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33
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Wang D, Fang M, Shen N, Li L, Wang W, Wang L, Lin H. Inhibiting post-translational core fucosylation protects against albumin-induced proximal tubular epithelial cell injury. Am J Transl Res 2017; 9:4415-4427. [PMID: 29118904 PMCID: PMC5666051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2017] [Accepted: 09/10/2017] [Indexed: 06/07/2023]
Abstract
Albuminuria is an independent risk factor for renal interstitial fibrosis (RIF). Glomerular-filtered albumin in endocytic and non-endocytic pathways may injure proximal tubular epithelial cells (PTECs) via megalin and TGFβRII, respectively. Since megalin and TGFβRII are both modified by post-translational core fucosylation, which plays a critical role in RIF. Thus, we sought to identify whether core fucosylation is a potential target for reducing albumin-induced injury to PTECs. We constructed a human PTEC-derived cell line (HK-2 cells) and established an in vitro model of bovine serum albumin (BSA) injury. RNAi was used to inhibit the expression of megalin, TGFβRII, and Fut8. Western blotting, immunostaining, ELISA, lectin blotting, and fluorescence-activated cell sorting were used to identify BSA-induced endocytic and non-endocytic damage in HK-2 cells. Fut8 is a core fucosylation-related gene, which is significantly increased in HK-2 cells following an incubation with BSA. Fut8 siRNA significantly reduced the core fucosylation of megalin and TGFβRII and also inhibited the activation of the TGFβ/TGFβRII/Smad2/3 signaling pathway. Furthermore, Fut8 siRNA could reduce monocyte chemotactic protein-1, reactive oxygen species, and apoptosis, as well as significantly decrease the fibronectin and collagen I levels in BSA-overloaded HK-2 cells. Core fucosylation inhibition was more effective than inhibiting either megalin or TGFβRII for the prevention of albumin-induced injury to PTECs. Our findings indicate that post-translational core fucosylation is essential for the albumin-induced injury to PTECs. Thus, the inhibition of core fucosylation could effectively alleviate albumin-induced endocytic and non-endocytic injury to PTECs. Our study provides a potential therapeutic target for albuminuria-induced injury.
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Affiliation(s)
- Dapeng Wang
- Department of Nephrology, The First Affiliated Hospital, Institute for Nephrology Research of Dalian Medical University, Center for Kidney Diseases Translational Medicine of Liaoning ProvinceDalian, China
| | - Ming Fang
- Postgraduate School of Dalian Medical UniversityDalian, China
| | - Nan Shen
- Department of Nephrology, The First Affiliated Hospital, Institute for Nephrology Research of Dalian Medical University, Center for Kidney Diseases Translational Medicine of Liaoning ProvinceDalian, China
| | - Longkai Li
- Department of Nephrology, The First Affiliated Hospital, Institute for Nephrology Research of Dalian Medical University, Center for Kidney Diseases Translational Medicine of Liaoning ProvinceDalian, China
| | - Weidong Wang
- Department of Nephrology, The First Affiliated Hospital, Institute for Nephrology Research of Dalian Medical University, Center for Kidney Diseases Translational Medicine of Liaoning ProvinceDalian, China
| | - Lingyu Wang
- Department of Nephrology, The First Affiliated Hospital, Institute for Nephrology Research of Dalian Medical University, Center for Kidney Diseases Translational Medicine of Liaoning ProvinceDalian, China
| | - Hongli Lin
- Department of Nephrology, The First Affiliated Hospital, Institute for Nephrology Research of Dalian Medical University, Center for Kidney Diseases Translational Medicine of Liaoning ProvinceDalian, China
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34
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Role of albumin and its modifications in glomerular injury. Pflugers Arch 2017; 469:975-982. [PMID: 28735420 DOI: 10.1007/s00424-017-2029-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2017] [Accepted: 07/05/2017] [Indexed: 02/06/2023]
Abstract
Albuminuria is both a characteristic hallmark and a known risk factor for progressive glomerular disease. Although the molecular basis for a potential causative role for albuminuria in progressive chronic kidney disease remains poorly understood, there have been several recent advances in our understanding of the role of albumin, and its molecular modifications, in the development and progression of glomerular disease. This review discusses recent findings related to the ability of albumin and its associated factors to directly induce podocyte and glomerular injury. Additional recent studies confirming the ability and mechanisms by which podocytes endocytose albumin are also discussed. Lastly, we present several known molecular modifications in the albumin molecule itself, as well as substances bound to it, which may be important and potentially clinically relevant mediators of albumin-induced glomerular injury. These recent findings may create entirely new opportunities to develop novel future therapies directed at albumin that could potentially help reduce podocyte and renal tubular injury and slow the progression of chronic glomerular disease.
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35
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Argyropoulos CP, Chen SS, Ng YH, Roumelioti ME, Shaffi K, Singh PP, Tzamaloukas AH. Rediscovering Beta-2 Microglobulin As a Biomarker across the Spectrum of Kidney Diseases. Front Med (Lausanne) 2017; 4:73. [PMID: 28664159 PMCID: PMC5471312 DOI: 10.3389/fmed.2017.00073] [Citation(s) in RCA: 158] [Impact Index Per Article: 22.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2017] [Accepted: 05/26/2017] [Indexed: 12/28/2022] Open
Abstract
There is currently an unmet need for better biomarkers across the spectrum of renal diseases. In this paper, we revisit the role of beta-2 microglobulin (β2M) as a biomarker in patients with chronic kidney disease and end-stage renal disease. Prior to reviewing the numerous clinical studies in the area, we describe the basic biology of β2M, focusing in particular on its role in maintaining the serum albumin levels and reclaiming the albumin in tubular fluid through the actions of the neonatal Fc receptor. Disorders of abnormal β2M function arise as a result of altered binding of β2M to its protein cofactors and the clinical manifestations are exemplified by rare human genetic conditions and mice knockouts. We highlight the utility of β2M as a predictor of renal function and clinical outcomes in recent large database studies against predictions made by recently developed whole body population kinetic models. Furthermore, we discuss recent animal data suggesting that contrary to textbook dogma urinary β2M may be a marker for glomerular rather than tubular pathology. We review the existing literature about β2M as a biomarker in patients receiving renal replacement therapy, with particular emphasis on large outcome trials. We note emerging proteomic data suggesting that β2M is a promising marker of chronic allograft nephropathy. Finally, we present data about the role of β2M as a biomarker in a number of non-renal diseases. The goal of this comprehensive review is to direct attention to the multifaceted role of β2M as a biomarker, and its exciting biology in order to propose the next steps required to bring this recently rediscovered biomarker into the twenty-first century.
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Affiliation(s)
- Christos P Argyropoulos
- Nephrology Division, Department of Internal Medicine, University of New Mexico School of Medicine, Albuquerque, NM, United States
| | - Shan Shan Chen
- Nephrology Division, Department of Internal Medicine, University of New Mexico School of Medicine, Albuquerque, NM, United States
| | - Yue-Harn Ng
- Nephrology Division, Department of Internal Medicine, University of New Mexico School of Medicine, Albuquerque, NM, United States
| | - Maria-Eleni Roumelioti
- Nephrology Division, Department of Internal Medicine, University of New Mexico School of Medicine, Albuquerque, NM, United States
| | - Kamran Shaffi
- Nephrology Division, Department of Internal Medicine, University of New Mexico School of Medicine, Albuquerque, NM, United States
| | - Pooja P Singh
- Nephrology Division, Department of Internal Medicine, University of New Mexico School of Medicine, Albuquerque, NM, United States
| | - Antonios H Tzamaloukas
- Nephrology Division, Department of Internal Medicine, University of New Mexico School of Medicine, Albuquerque, NM, United States.,Raymond G. Murphy VA Medical Center Albuquerque, Albuquerque, NM, United States
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36
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Moriyama T, Sasaki K, Karasawa K, Uchida K, Nitta K. Intracellular transcytosis of albumin in glomerular endothelial cells after endocytosis through caveolae. J Cell Physiol 2017; 232:3565-3573. [DOI: 10.1002/jcp.25817] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2016] [Revised: 01/20/2017] [Accepted: 01/20/2017] [Indexed: 02/02/2023]
Affiliation(s)
- Takahito Moriyama
- Department of Medicine; Kidney Center; Tokyo Women's Medical University; Tokyo Japan
| | - Kayo Sasaki
- Department of Medicine; Kidney Center; Tokyo Women's Medical University; Tokyo Japan
| | - Kazunori Karasawa
- Department of Medicine; Kidney Center; Tokyo Women's Medical University; Tokyo Japan
| | - Keiko Uchida
- Department of Medicine; Kidney Center; Tokyo Women's Medical University; Tokyo Japan
| | - Kosaku Nitta
- Department of Medicine; Kidney Center; Tokyo Women's Medical University; Tokyo Japan
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37
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Castrop H, Schießl IM. Novel routes of albumin passage across the glomerular filtration barrier. Acta Physiol (Oxf) 2017; 219:544-553. [PMID: 27452481 DOI: 10.1111/apha.12760] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Revised: 06/13/2016] [Accepted: 07/20/2016] [Indexed: 12/20/2022]
Abstract
Albuminuria is a hallmark of kidney diseases of various aetiologies and an unambiguous symptom of the compromised integrity of the glomerular filtration barrier. Furthermore, there is increasing evidence that albuminuria per se aggravates the development and progression of chronic kidney disease. This review covers new aspects of the movement of large plasma proteins across the glomerular filtration barrier in health and disease. Specifically, this review focuses on the role of endocytosis and transcytosis of albumin by podocytes, which constitutes a new pathway of plasma proteins across the filtration barrier. Thus, we summarize what is known about the mechanisms of albumin endocytosis by podocytes and address the fate of the endocytosed albumin, which is directed to lysosomal degradation or transcellular movement with subsequent vesicular release into the urinary space. We also address the functional consequences of overt albumin endocytosis by podocytes, such as the formation of pro-inflammatory cytokines, which might eventually result in a deterioration of podocyte function. Finally, we consider the diagnostic potential of podocyte-derived albumin-containing vesicles in the urine as an early marker of a compromised glomerular barrier function. In terms of new technical approaches, the review covers how our knowledge of the movement of albumin across the glomerular filtration barrier has expanded by the use of new intravital imaging techniques.
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Affiliation(s)
- H. Castrop
- Institute of Physiology; University of Regensburg; Regensburg Germany
| | - I. M. Schießl
- Institute of Physiology; University of Regensburg; Regensburg Germany
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38
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Photoluminescent Gold Nanoclusters in Cancer Cells: Cellular Uptake, Toxicity, and Generation of Reactive Oxygen Species. Int J Mol Sci 2017; 18:ijms18020378. [PMID: 28208642 PMCID: PMC5343913 DOI: 10.3390/ijms18020378] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2016] [Accepted: 02/02/2017] [Indexed: 11/23/2022] Open
Abstract
In recent years, photoluminescent gold nanoclusters have attracted considerable interest in both fundamental biomedical research and practical applications. Due to their ultrasmall size, unique molecule-like optical properties, and facile synthesis gold nanoclusters have been considered very promising photoluminescent agents for biosensing, bioimaging, and targeted therapy. Yet, interaction of such ultra-small nanoclusters with cells and other biological objects remains poorly understood. Therefore, the assessment of the biocompatibility and potential toxicity of gold nanoclusters is of major importance before their clinical application. In this study, the cellular uptake, cytotoxicity, and intracellular generation of reactive oxygen species (ROS) of bovine serum albumin-encapsulated (BSA-Au NCs) and 2-(N-morpholino) ethanesulfonic acid (MES)-capped photoluminescent gold nanoclusters (Au-MES NCs) were investigated. The results showed that BSA-Au NCs accumulate in cells in a similar manner as BSA alone, indicating an endocytotic uptake mechanism while ultrasmall Au-MES NCs were distributed homogeneously throughout the whole cell volume including cell nucleus. The cytotoxicity of BSA-Au NCs was negligible, demonstrating good biocompatibility of such BSA-protected Au NCs. In contrast, possibly due to ultrasmall size and thin coating layer, Au-MES NCs exhibited exposure time-dependent high cytotoxicity and higher reactivity which led to highly increased generation of reactive oxygen species. The results demonstrate the importance of the coating layer to biocompatibility and toxicity of ultrasmall photoluminescent gold nanoclusters.
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39
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Fu Y, Zhu JY, Richman A, Zhang Y, Xie X, Das JR, Li J, Ray PE, Han Z. APOL1-G1 in Nephrocytes Induces Hypertrophy and Accelerates Cell Death. J Am Soc Nephrol 2016; 28:1106-1116. [PMID: 27864430 DOI: 10.1681/asn.2016050550] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2016] [Accepted: 10/09/2016] [Indexed: 01/17/2023] Open
Abstract
People of African ancestry carrying certain APOL1 mutant alleles are at elevated risk of developing renal diseases. However, the mechanisms underlying APOL1-associated renal diseases are unknown. Because the APOL1 gene is unique to humans and some primates, new animal models are needed to understand the function of APOL1 in vivo We generated transgenic Drosophila fly lines expressing the human APOL1 wild type allele (G0) or the predominant APOL1 risk allele (G1) in different tissues. Ubiquitous expression of APOL1 G0 or G1 in Drosophila induced lethal phenotypes, and G1 was more toxic than was G0. Selective expression of the APOL1 G0 or G1 transgene in nephrocytes, fly cells homologous to mammalian podocytes, induced increased endocytic activity and accumulation of hemolymph proteins, dextran particles, and silver nitrate. As transgenic flies with either allele aged, nephrocyte function declined, cell size increased, and nephrocytes died prematurely. Compared with G0-expressing cells, however, G1-expressing cells showed more dramatic phenotypes, resembling those observed in cultured mammalian podocytes overexpressing APOL1-G1. Expressing the G0 or G1 APOL1 transgene in nephrocytes also impaired the acidification of organelles. We conclude that expression of an APOL1 transgene initially enhances nephrocyte function, causing hypertrophy and subsequent cell death. This new Drosophila model uncovers a novel mechanism by which upregulated expression of APOL1-G1 could precipitate renal disease in humans. Furthermore, this model may facilitate the identification of APOL1-interacting molecules that could serve as new drug targets to treat APOL1-associated renal diseases.
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Affiliation(s)
- Yulong Fu
- Center for Cancer and Immunology Research, Washington, DC
| | - Jun-Yi Zhu
- Center for Cancer and Immunology Research, Washington, DC
| | - Adam Richman
- Center for Cancer and Immunology Research, Washington, DC
| | - Yi Zhang
- Center for Cancer and Immunology Research, Washington, DC.,Center for Genetic Medicine Research, Washington, DC
| | - Xuefang Xie
- Center for Genetic Medicine Research, Washington, DC
| | - Jharna R Das
- Center for Genetic Medicine Research, Washington, DC.,Division of Nephrology, Children's National Health Systems, Washington, DC; and.,Department of Pediatrics, The George Washington University School of Medicine and Health Sciences, Washington, DC
| | - Jinliang Li
- Center for Genetic Medicine Research, Washington, DC.,Department of Pediatrics, The George Washington University School of Medicine and Health Sciences, Washington, DC
| | - Patricio E Ray
- Center for Genetic Medicine Research, Washington, DC.,Division of Nephrology, Children's National Health Systems, Washington, DC; and.,Department of Pediatrics, The George Washington University School of Medicine and Health Sciences, Washington, DC
| | - Zhe Han
- Center for Cancer and Immunology Research, Washington, DC; .,Department of Pediatrics, The George Washington University School of Medicine and Health Sciences, Washington, DC
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40
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Gong W, Yu J, Wang Q, Li S, Song J, Jia Z, Huang S, Zhang A. Estrogen-related receptor (ERR) γ protects against puromycin aminonucleoside-induced podocyte apoptosis by targeting PI3K/Akt signaling. Int J Biochem Cell Biol 2016; 78:75-86. [PMID: 27417234 DOI: 10.1016/j.biocel.2016.07.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2015] [Revised: 07/06/2016] [Accepted: 07/08/2016] [Indexed: 12/21/2022]
Abstract
Accumulating evidence has shown that podocyte apoptosis is of vital importance for the development of glomerulosclerosis and progressive loss of renal function. However, the molecular mechanisms leading to podocyte apoptosis are still elusive. In this study, we investigated the role of estrogen-related receptor (ERR) γ in podocyte apoptosis, as well as the underlying mechanisms. Treatment of PAN caused a dose- and time-dependent podocyte apoptosis in line with a significant downregulation of ERRγ. Interestingly, the occurrence of ERRγ downregulation appeared earlier than the onset of cell apoptosis, suggesting a potential that ERRγ reduction triggered apoptotic response in podocyte. To test this hypothesis, ERRγ siRNA was administered to the podocytes. Strikingly, ERRγ silencing resulted in a significant cell apoptosis accompanied with increased injury markers of B7-1 and cathepsin L and decreased podocyte protein nephrin. In contrast, overexpression of ERRγ remarkably attenuated PAN-induced cell apoptosis. Moreover, ERRγ overexpression stimulated PI3K/Akt signaling pathway evidenced by increased expression of PI3K subunits p85α and p110α and phosphorylated Akt. Importantly, a specific PI3K inhibitor LY294002 entirely reversed the anti-apoptotic effect of ERRγ following PAN treatment. Finally, we observed a striking downregulation of ERRγ in PAN-treated rat kidneys, suggesting that our cell model replicated the in vivo condition. Taken together, these data highly suggested that ERRγ played a novel role in modulating podocyte apoptosis by targeting PI3K/Akt signaling pathway.
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Affiliation(s)
- Wei Gong
- Department of Nephrology, Nanjing Children's Hospital Affiliated to Nanjing Medical University, Nanjing 210008, China; State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing 210029, China; Jiangsu Key Laboratory of Pediatrics, Nanjing Medical University, Nanjing 210029, China
| | - Jing Yu
- Department of Nephrology, Nanjing Children's Hospital Affiliated to Nanjing Medical University, Nanjing 210008, China; State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing 210029, China; Jiangsu Key Laboratory of Pediatrics, Nanjing Medical University, Nanjing 210029, China
| | - Qilei Wang
- Department of Nephrology, Nanjing Children's Hospital Affiliated to Nanjing Medical University, Nanjing 210008, China; Jiangsu Key Laboratory of Pediatrics, Nanjing Medical University, Nanjing 210029, China
| | - Shuzhen Li
- Department of Nephrology, Nanjing Children's Hospital Affiliated to Nanjing Medical University, Nanjing 210008, China; Nanjing Key Laboratory of Pediatrics, Nanjing 210008, China
| | - Jiayu Song
- Department of Nephrology, Nanjing Children's Hospital Affiliated to Nanjing Medical University, Nanjing 210008, China; State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing 210029, China; Jiangsu Key Laboratory of Pediatrics, Nanjing Medical University, Nanjing 210029, China
| | - Zhanjun Jia
- Department of Nephrology, Nanjing Children's Hospital Affiliated to Nanjing Medical University, Nanjing 210008, China; Jiangsu Key Laboratory of Pediatrics, Nanjing Medical University, Nanjing 210029, China; Nanjing Key Laboratory of Pediatrics, Nanjing 210008, China
| | - Songming Huang
- Department of Nephrology, Nanjing Children's Hospital Affiliated to Nanjing Medical University, Nanjing 210008, China; Jiangsu Key Laboratory of Pediatrics, Nanjing Medical University, Nanjing 210029, China; Nanjing Key Laboratory of Pediatrics, Nanjing 210008, China
| | - Aihua Zhang
- Department of Nephrology, Nanjing Children's Hospital Affiliated to Nanjing Medical University, Nanjing 210008, China; State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing 210029, China; Jiangsu Key Laboratory of Pediatrics, Nanjing Medical University, Nanjing 210029, China; Nanjing Key Laboratory of Pediatrics, Nanjing 210008, China.
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41
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Burlaka I, Nilsson LM, Scott L, Holtbäck U, Eklöf AC, Fogo AB, Brismar H, Aperia A. Prevention of apoptosis averts glomerular tubular disconnection and podocyte loss in proteinuric kidney disease. Kidney Int 2016; 90:135-48. [PMID: 27217195 PMCID: PMC6101029 DOI: 10.1016/j.kint.2016.03.026] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2015] [Revised: 02/19/2016] [Accepted: 03/10/2016] [Indexed: 01/09/2023]
Abstract
There is a great need for treatment that arrests progression of chronic kidney disease. Increased albumin in urine leads to apoptosis and fibrosis of podocytes and tubular cells and is a major cause of functional deterioration. There have been many attempts to target fibrosis, but because of the lack of appropriate agents, few have targeted apoptosis. Our group has described an ouabain-activated Na,K-ATPase/IP3R signalosome, which protects from apoptosis. Here we show that albumin uptake in primary rat renal epithelial cells is accompanied by a time- and dose-dependent mitochondrial accumulation of the apoptotic factor Bax, down-regulation of the antiapoptotic factor Bcl-xL and mitochondrial membrane depolarization. Ouabain opposes these effects and protects from apoptosis in albumin-exposed proximal tubule cells and podocytes. The efficacy of ouabain as an antiapoptotic and kidney-protective therapeutic tool was then tested in rats with passive Heymann nephritis, a model of proteinuric chronic kidney disease. Chronic ouabain treatment preserved renal function, protected from renal cortical apoptosis, up-regulated Bax, down-regulated Bcl-xL, and rescued from glomerular tubular disconnection and podocyte loss. Thus we have identified a novel clinically feasible therapeutic tool, which has the potential to protect from apoptosis and rescue from loss of functional tissue in chronic proteinuric kidney disease.
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Affiliation(s)
- Ievgeniia Burlaka
- Science for Life Laboratory, Department of Women's and Children's Health, Karolinska Institutet, Solna, Sweden
| | - Linnéa M Nilsson
- Science for Life Laboratory, Department of Applied Physics, Royal Institute of Technology, Solna, Sweden
| | - Lena Scott
- Science for Life Laboratory, Department of Women's and Children's Health, Karolinska Institutet, Solna, Sweden.
| | - Ulla Holtbäck
- Science for Life Laboratory, Department of Women's and Children's Health, Karolinska Institutet, Solna, Sweden
| | - Ann-Christine Eklöf
- Science for Life Laboratory, Department of Women's and Children's Health, Karolinska Institutet, Solna, Sweden
| | - Agnes B Fogo
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Hjalmar Brismar
- Science for Life Laboratory, Department of Women's and Children's Health, Karolinska Institutet, Solna, Sweden; Science for Life Laboratory, Department of Applied Physics, Royal Institute of Technology, Solna, Sweden
| | - Anita Aperia
- Science for Life Laboratory, Department of Women's and Children's Health, Karolinska Institutet, Solna, Sweden.
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42
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Jarad G, Knutsen RH, Mecham RP, Miner JH. Albumin contributes to kidney disease progression in Alport syndrome. Am J Physiol Renal Physiol 2016; 311:F120-30. [PMID: 27147675 DOI: 10.1152/ajprenal.00456.2015] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2015] [Accepted: 04/29/2016] [Indexed: 12/31/2022] Open
Abstract
Alport syndrome is a familial kidney disease caused by defects in the collagen type IV network of the glomerular basement membrane. Lack of collagen-α3α4α5(IV) changes the glomerular basement membrane morphologically and functionally, rendering it leaky to albumin and other plasma proteins. Filtered albumin has been suggested to be a cause of the glomerular and tubular injuries observed at advanced stages of Alport syndrome. To directly investigate the role that albumin plays in the progression of disease in Alport syndrome, we generated albumin knockout (Alb(-/-)) mice to use as a tool for removing albuminuria as a component of kidney disease. Mice lacking albumin were healthy and indistinguishable from control littermates, although they developed hypertriglyceridemia. Dyslipidemia was observed in Alb(+/-) mice, which displayed half the normal plasma albumin concentration. Alb mutant mice were bred to collagen-α3(IV) knockout (Col4a3(-/-)) mice, which are a model for human Alport syndrome. Lack of circulating and filtered albumin in Col4a3(-/-);Alb(-/-) mice resulted in dramatically improved kidney disease outcomes, as these mice lived 64% longer than did Col4a3(-/-);Alb(+/+) and Col4a3(-/-);Alb(+/-) mice, despite similar blood pressures and serum triglyceride levels. Further investigations showed that the absence of albumin correlated with reduced transforming growth factor-β1 signaling as well as reduced tubulointerstitial, glomerular, and podocyte pathology. We conclude that filtered albumin is injurious to kidney cells in Alport syndrome and perhaps in other proteinuric kidney diseases, including diabetic nephropathy.
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Affiliation(s)
- George Jarad
- Division of Nephrology, Department of Internal Medicine, Washington University School of Medicine, St. Louis, Missouri; and
| | - Russell H Knutsen
- Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, Missouri
| | - Robert P Mecham
- Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, Missouri
| | - Jeffrey H Miner
- Division of Nephrology, Department of Internal Medicine, Washington University School of Medicine, St. Louis, Missouri; and Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, Missouri
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Kasztan M, Piwkowska A, Kreft E, Rogacka D, Audzeyenka I, Szczepanska-Konkel M, Jankowski M. Extracellular purines' action on glomerular albumin permeability in isolated rat glomeruli: insights into the pathogenesis of albuminuria. Am J Physiol Renal Physiol 2016; 311:F103-11. [PMID: 27076649 DOI: 10.1152/ajprenal.00567.2015] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2015] [Accepted: 04/12/2016] [Indexed: 12/20/2022] Open
Abstract
Purinoceptors (adrengeric receptors and P2 receptors) are expressed on the cellular components of the glomerular filtration barrier, and their activation may affect glomerular permeability to albumin, which may ultimately lead to albuminuria, a well-established risk factor for the progression of chronic kidney disease and development of cardiovascular diseases. We investigated the mechanisms underlying the in vitro and in vivo purinergic actions on glomerular filter permeability to albumin by measuring convectional albumin permeability (Palb) in a single isolated rat glomerulus based on the video microscopy method. Primary cultured rat podocytes were used for the analysis of Palb, cGMP accumulation, PKG-Iα dimerization, and immunofluorescence. In vitro, natural nucleotides (ATP, ADP, UTP, and UDP) and nonmetabolized ATP analogs (2-meSATP and ATP-γ-S) increased Palb in a time- and concentration-dependent manner. The effects were dependent on P2 receptor activation, nitric oxide synthase, and cytoplasmic guanylate cyclase. ATP analogs significantly increased Palb, cGMP accumulation, and subcortical actin reorganization in a PKG-dependent but nondimer-mediated route in cultured podocytes. In vivo, 2-meSATP and ATP-γ-S increased Palb but did not significantly affect urinary albumin excretion. Both agonists enhanced the clathrin-mediated endocytosis of albumin in podocytes. A product of adenine nucleotides hydrolysis, adenosine, increased the permeability of the glomerular barrier via adrenergic receptors in a dependent and independent manner. Our results suggest that the extracellular nucleotides that stimulate an increase of glomerular Palb involve nitric oxide synthase and cytoplasmic guanylate cyclase with actin reorganization in podocytes.
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Affiliation(s)
- Małgorzata Kasztan
- Department of Therapy Monitoring and Pharmacogenetics, Medical University of Gdansk, Gdansk, Poland
| | - Agnieszka Piwkowska
- Laboratory of Molecular and Cellular Nephrology, Mossakowski Medical Research Centre Polish Academy of Sciences, Gdansk, Poland
| | - Ewelina Kreft
- Department of Therapy Monitoring and Pharmacogenetics, Medical University of Gdansk, Gdansk, Poland
| | - Dorota Rogacka
- Laboratory of Molecular and Cellular Nephrology, Mossakowski Medical Research Centre Polish Academy of Sciences, Gdansk, Poland
| | - Irena Audzeyenka
- Laboratory of Molecular and Cellular Nephrology, Mossakowski Medical Research Centre Polish Academy of Sciences, Gdansk, Poland
| | | | - Maciej Jankowski
- Department of Clinical Chemistry, Medical University of Gdansk, Gdansk, Poland; and Laboratory of Molecular and Cellular Nephrology, Mossakowski Medical Research Centre Polish Academy of Sciences, Gdansk, Poland
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Venkatareddy M, Verma R, Kalinowski A, Patel SR, Shisheva A, Garg P. Distinct Requirements for Vacuolar Protein Sorting 34 Downstream Effector Phosphatidylinositol 3-Phosphate 5-Kinase in Podocytes Versus Proximal Tubular Cells. J Am Soc Nephrol 2016; 27:2702-19. [PMID: 26825532 DOI: 10.1681/asn.2015050555] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2015] [Accepted: 12/09/2015] [Indexed: 12/16/2022] Open
Abstract
The mechanisms by which the glomerular filtration barrier prevents the loss of large macromolecules and simultaneously, maintains the filter remain poorly understood. Recent studies proposed that podocytes have an active role in both the endocytosis of filtered macromolecules and the maintenance of the filtration barrier. Deletion of a key endosomal trafficking regulator, the class 3 phosphatidylinositol (PtdIns) 3-kinase vacuolar protein sorting 34 (Vps34), in podocytes results in aberrant endosomal membrane morphology and podocyte dysfunction. We recently showed that the vacuolation phenotype in cultured Vps34-deficient podocytes is caused by the absence of a substrate for the Vps34 downstream effector PtdIns 3-phosphate 5-kinase (PIKfyve), which phosphorylates Vps34-generated PtdIns(3)P to produce PtdIns (3,5)P2. PIKfyve perturbation and PtdIns(3,5)P2 reduction result in massive membrane vacuolation along the endosomal system, but the cell-specific functions of PIKfyve in vivo remain unclear. We show here that the genetic deletion of PIKfyve in endocytically active proximal tubular cells resulted in the development of large cytoplasmic vacuoles caused by arrested endocytic traffic progression at a late-endosome stage. In contrast, deletion of PIKfyve in glomerular podocytes did not significantly alter the endosomal morphology, even in age 18-month-old mice. However, on culturing, the PIKfyve-deleted podocytes developed massive cytoplasmic vacuoles. In summary, these data suggest that glomerular podocytes and proximal tubules have different requirements for PIKfyve function, likely related to distinct in vivo needs for endocytic flux.
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Affiliation(s)
- Madhusudan Venkatareddy
- Division of Nephrology, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan; and
| | - Rakesh Verma
- Division of Nephrology, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan; and
| | - Anne Kalinowski
- Division of Nephrology, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan; and
| | - Sanjeevkumar R Patel
- Division of Nephrology, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan; and
| | - Assia Shisheva
- Department of Physiology, Wayne State University School of Medicine, Detroit, Michigan
| | - Puneet Garg
- Division of Nephrology, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan; and
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Abstract
Podocytes are highly specialized cells of the kidney glomerulus that wrap around capillaries and that neighbor cells of the Bowman’s capsule. When it comes to glomerular filtration, podocytes play an active role in preventing plasma proteins from entering the urinary ultrafiltrate by providing a barrier comprising filtration slits between foot processes, which in aggregate represent a dynamic network of cellular extensions. Foot processes interdigitate with foot processes from adjacent podocytes and form a network of narrow and rather uniform gaps. The fenestrated endothelial cells retain blood cells but permit passage of small solutes and an overlying basement membrane less permeable to macromolecules, in particular to albumin. The cytoskeletal dynamics and structural plasticity of podocytes as well as the signaling between each of these distinct layers are essential for an efficient glomerular filtration and thus for proper renal function. The genetic or acquired impairment of podocytes may lead to foot process effacement (podocyte fusion or retraction), a morphological hallmark of proteinuric renal diseases. Here, we briefly discuss aspects of a contemporary view of podocytes in glomerular filtration, the patterns of structural changes in podocytes associated with common glomerular diseases, and the current state of basic and clinical research.
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Affiliation(s)
- Jochen Reiser
- Department of Medicine, Rush University Medical Center, Chicago, IL, USA
| | - Mehmet M Altintas
- Department of Medicine, Rush University Medical Center, Chicago, IL, USA
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Masood H, Che R, Zhang A. Inflammasomes in the Pathophysiology of Kidney Diseases. KIDNEY DISEASES 2015; 1:187-93. [PMID: 27536679 DOI: 10.1159/000438843] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2015] [Accepted: 07/17/2015] [Indexed: 01/08/2023]
Abstract
BACKGROUND The inflammasome is a complex of proteins in the cytoplasm that consists of three main components: a sensor protein (receptor), an adapter protein and caspase-1. Inflammasomes are the critical components of innate immunity and have been gradually recognized as a critical mediator in various autoimmune diseases; also, their role in chronic kidney disease and acute kidney injury has been gradually accepted. SUMMARY Inflammasomes triggered by infectious or sterile injuries transfer proinflammatory mediators into mature ones through innate danger-signaling platforms. Information on inflammasomes in kidney disease will help to uncover the underlying mechanisms of nephropathy and provide novel therapeutic targets in the future. KEY MESSAGES The inflammasomes can be activated by a series of exogenous and endogenous stimuli, including pathogen-and danger-associated molecular patterns released from or caused by damaged cells. The NACHT, LRR and PYD domain-containing protein 3 (NLRP3) in the kidney exerts its effect not only by the 'canonical' pathway of IL-1β and IL-18 secretion but also by 'noncanonical' pathways, such as tumor growth factor-β signaling, epithelial-mesenchymal transition and fibrosis. In both clinical and experimental data, the NLRP3 inflammasome was reported to be involved in the pathogenesis of chronic kidney disease and acute kidney injury. However, the underlying mechanisms are not fully understood. Therapies targeting the activation of the NLRP3 inflammasome or blocking its downstream effectors appear attractive for the pursuit of neuropathy treatments.
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Affiliation(s)
- Humaira Masood
- Department of Nephrology, Nanjing Children's Hospital, Nanjing Medical University, Nanjing, PR China
| | - Ruochen Che
- Department of Nephrology, Nanjing Children's Hospital, Nanjing Medical University, Nanjing, PR China
| | - Aihua Zhang
- Department of Nephrology, Nanjing Children's Hospital, Nanjing Medical University, Nanjing, PR China
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Schießl IM, Hammer A, Kattler V, Gess B, Theilig F, Witzgall R, Castrop H. Intravital Imaging Reveals Angiotensin II-Induced Transcytosis of Albumin by Podocytes. J Am Soc Nephrol 2015; 27:731-44. [PMID: 26116357 DOI: 10.1681/asn.2014111125] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2014] [Accepted: 05/11/2015] [Indexed: 11/03/2022] Open
Abstract
Albuminuria is a hallmark of kidney disease of various etiologies and usually caused by deterioration of glomerular filtration barrier integrity. We recently showed that angiotensin II (Ang II) acutely increases albumin filtration in the healthy kidney. Here, we used intravital microscopy to assess the effects of Ang II on podocyte function in rats. Acute infusion of 30, 60, or 80 ng/kg per minute Ang II enhanced the endocytosis of albumin by activation of the type 1 Ang II receptor and resulted in an average (±SEM) of 3.7±2.2, 72.3±18.6 (P<0.001), and 239.4±34.6 µm(3) (P<0.001) albumin-containing vesicles per glomerulus, respectively, compared with none at baseline or 10 ng/kg per minute Ang II. Immunostaining of Ang II-infused kidneys confirmed the presence of albumin-containing vesicles, which colocalized with megalin, in podocin-positive cells. Furthermore, podocyte endocytosis of albumin was markedly reduced in the presence of gentamicin, a competitive inhibitor of megalin-dependent endocytosis. Ang II infusion increased the concentration of albumin in the subpodocyte space, a potential source for endocytic protein uptake, and gentamicin further increased this concentration. Some endocytic vesicles were acidified and colocalized with LysoTracker. Most vesicles migrated from the capillary to the apical aspect of the podocyte and were eventually released into the urinary space. This transcytosis accounted for approximately 10% of total albumin filtration. In summary, the transcellular transport of proteins across the podocyte constitutes a new pathway of glomerular protein filtration. Ang II enhances the endocytosis and transcytosis of plasma albumin by podocytes, which may eventually impair podocyte function.
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Affiliation(s)
| | | | | | | | - Franziska Theilig
- Department of Medicine, University of Fribourg, Fribourg, Switzerland
| | - Ralph Witzgall
- Molecular and Cellular Anatomy, University of Regensburg, Regensburg, Germany; and
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Inoue K, Ishibe S. Podocyte endocytosis in the regulation of the glomerular filtration barrier. Am J Physiol Renal Physiol 2015; 309:F398-405. [PMID: 26084928 DOI: 10.1152/ajprenal.00136.2015] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2015] [Accepted: 06/15/2015] [Indexed: 02/06/2023] Open
Abstract
Severe defects in the glomerular filtration barrier result in nephrotic syndrome, which is characterized by massive proteinuria. The podocyte, a specialized epithelial cell with interdigitating foot processes separated by a slit diaphragm, plays a vital role in regulating the passage of proteins from the capillary lumen to Bowman's space. Recent findings suggest a critical role for endocytosis in podocyte biology as highlighted by genetic mouse models of disease and human genetic mutations that result in the loss of the integrity of the glomerular filtration barrier. In vitro podocyte studies have also unraveled a plethora of constituents that are differentially internalized to maintain homeostasis. These observations provide a framework and impetus for understanding the precise regulation of podocyte endocytic machinery in both health and disease.
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Affiliation(s)
- Kazunori Inoue
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut
| | - Shuta Ishibe
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut
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Chung JJ, Huber TB, Gödel M, Jarad G, Hartleben B, Kwoh C, Keil A, Karpitskiy A, Hu J, Huh CJ, Cella M, Gross RW, Miner JH, Shaw AS. Albumin-associated free fatty acids induce macropinocytosis in podocytes. J Clin Invest 2015; 125:2307-16. [PMID: 25915582 DOI: 10.1172/jci79641] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2014] [Accepted: 03/19/2015] [Indexed: 01/26/2023] Open
Abstract
Podocytes are specialized epithelial cells in the kidney glomerulus that play important structural and functional roles in maintaining the filtration barrier. Nephrotic syndrome results from a breakdown of the kidney filtration barrier and is associated with proteinuria, hyperlipidemia, and edema. Additionally, podocytes undergo changes in morphology and internalize plasma proteins in response to this disorder. Here, we used fluid-phase tracers in murine models and determined that podocytes actively internalize fluid from the plasma and that the rate of internalization is increased when the filtration barrier is disrupted. In cultured podocytes, the presence of free fatty acids (FFAs) associated with serum albumin stimulated macropinocytosis through a pathway that involves FFA receptors, the Gβ/Gγ complex, and RAC1. Moreover, mice with elevated levels of plasma FFAs as the result of a high-fat diet were more susceptible to Adriamycin-induced proteinuria than were animals on standard chow. Together, these results support a model in which podocytes sense the disruption of the filtration barrier via FFAs bound to albumin and respond by enhancing fluid-phase uptake. The response to FFAs may function in the development of nephrotic syndrome by amplifying the effects of proteinuria.
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Abstract
PURPOSE OF REVIEW To focus on the latest data that elucidate the role of the NLRP3 inflammasome in kidney diseases. RECENT FINDINGS The NLRP3 inflammasome is not limited by the traditional microbial stimuli of innate immunity and its connection with autophagy, apoptosis, fibrosis, and pro-inflammatory cytokines has broader implications for a variety of kidney diseases. In a wide spectrum of glomerular and tubulointerstitial diseases, the NLRP3 inflammasome is upregulated in both classical immune cells such as infiltrating macrophages and resident dendritic cells as well as in renal tubular epithelial cells, and even podocytes. Inhibition of the NLRP3 inflammasome ameliorates renal injury in a variety of animal models. Interestingly, this extends to models of proteinuria, which suggests that the deleterious effect of albuminuria on the proximal tubular epithelium and podocytes is, in part, mediated by inflammasome activation. SUMMARY Recent studies in animal models, and limited studies in humans, suggest a broad role for inflammasome activation in renal disease. Surprisingly, individual components of the inflammasome, independent of inflammasome activation, may also contribute to progressive renal injury. Additional, studies are needed to define the relative importance of the inflammasome in specific diseases and the therapeutic opportunities afforded by targeting the inflammasome.
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