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Schindler M, Endlich N. Zebrafish as a model for podocyte research. Am J Physiol Renal Physiol 2024; 326:F369-F381. [PMID: 38205541 DOI: 10.1152/ajprenal.00335.2023] [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: 10/18/2023] [Revised: 12/25/2023] [Accepted: 12/25/2023] [Indexed: 01/12/2024] Open
Abstract
Podocytes, specialized postmitotic cells, are central players in various kidney-related diseases. Zebrafish have become a valuable model system for studying podocyte biology because they are genetically easy to manipulate, transparent, and their glomerular structure is similar to that of mammals. This review provides an overview of the knowledge of podocyte biology in zebrafish larvae, with particular focus on their essential contribution to understanding the mechanisms that underlie kidney diseases as well as supporting drug development. In addition, special attention is given to advances in live-imaging techniques allowing the observation of dynamic processes, including podocyte motility, podocyte process behavior, and glomerulus maturation. The review further addresses the functional aspects of podocytes in zebrafish larvae. This includes topics such as glomerular filtration, ultrastructural analyses, and evaluation of podocyte response to nephrotoxic insults. Studies presented in this context have provided important insights into the maintenance and resistance of the glomerular filtration barrier in zebrafish larvae and explored the potential transferability of these findings to mammals such as mice, rats, and most importantly, humans. The recent ability to identify potential therapeutic targets represents a promising new way to identify drugs that could effectively treat podocyte-associated glomerulopathies in humans. In summary, this review gives an overview about the importance of zebrafish as a model for podocyte-related disease and targeted drug development. It also highlights the key role of advanced imaging techniques in transparent zebrafish larvae, improving our understanding of glomerular diseases and the significant potential for translation of these findings to humans.
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Affiliation(s)
- Maximilian Schindler
- Department of Anatomy and Cell Biology, University Medicine Greifswald, Greifswald, Germany
| | - Nicole Endlich
- Department of Anatomy and Cell Biology, University Medicine Greifswald, Greifswald, Germany
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Drummond BE, Ercanbrack WS, Wingert RA. Modeling Podocyte Ontogeny and Podocytopathies with the Zebrafish. J Dev Biol 2023; 11:jdb11010009. [PMID: 36810461 PMCID: PMC9944608 DOI: 10.3390/jdb11010009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2023] [Revised: 02/11/2023] [Accepted: 02/17/2023] [Indexed: 02/22/2023] Open
Abstract
Podocytes are exquisitely fashioned kidney cells that serve an essential role in the process of blood filtration. Congenital malformation or damage to podocytes has dire consequences and initiates a cascade of pathological changes leading to renal disease states known as podocytopathies. In addition, animal models have been integral to discovering the molecular pathways that direct the development of podocytes. In this review, we explore how researchers have used the zebrafish to illuminate new insights about the processes of podocyte ontogeny, model podocytopathies, and create opportunities to discover future therapies.
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Sopel N, Müller-Deile J. Zebrafish Model to Study Podocyte Function Within the Glomerular Filtration Barrier. Methods Mol Biol 2023; 2664:145-157. [PMID: 37423988 DOI: 10.1007/978-1-0716-3179-9_11] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/11/2023]
Abstract
The zebrafish model has been used in many different fields of research because of its high homology to the human genome, its easy genetic manipulation, its high fecundity, and its rapid development. For glomerular diseases, zebrafish larvae have proven to be a versatile tool to study the contribution of different genes, because the zebrafish pronephros is very comparable to the human kidney in function and ultrastructure. Here we describe the principle and use of a simple screening assay based on the measurement of the fluorescence in the retinal vessel plexus of the Tg(l-fabp:DBP:eGFP) zebrafish line ("eye assay") to indirectly determine proteinuria as a hallmark of podocyte dysfunction. Furthermore, we illustrate how to analyze the obtained data and outline methods to attribute the findings to podocyte impairment.
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Affiliation(s)
- Nina Sopel
- Department of Medicine 4 - Nephrology and Hypertension, Universitätsklinikum Erlangen, Erlangen, Germany
- Friedrich-Alexander Universiät Erlangen-Nuremberg, Erlangen, Germany
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Zebrafish: A Model to Study and Understand the Diabetic Nephropathy and Other Microvascular Complications of Type 2 Diabetes Mellitus. Vet Sci 2022; 9:vetsci9070312. [PMID: 35878329 PMCID: PMC9323928 DOI: 10.3390/vetsci9070312] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Revised: 06/14/2022] [Accepted: 06/16/2022] [Indexed: 12/02/2022] Open
Abstract
Simple Summary Diabetes is a chronic metabolic disease characterized by high blood glucose levels (hyperglycemia). Type 2 diabetes mellitus (T2DM) and its complications are a worldwide public health problem, affecting people from all developed and developing countries. Hyperglycemia can cause damage to the vascular system and dysfunction of organs, such as the kidneys, heart, retina of the eyes, and nerves. Diabetic nephropathy (DN) is one of the most severe micro-vascular complications, which can lead to ESRD (end-stage renal disease). Zebrafish are ideal for wide-scale analysis or screening, due to their small size, quick growth, transparent embryos, vast number of offspring, and gene similarity with humans, which combine to make zebrafish an ideal model for diabetes. The readily available tools for gene editing using morpholinos or CRISPR/Cas9, as well as chemical/drug therapy by microinjection or skin absorption, enable zebrafish diabetes mellitus models to be established in a number of ways. In this review, we emphasize the physiological and pathological processes relating to micro-vascular problems in zebrafish, as well as the many experimental zebrafish models used to research DN, and the DN-related outcomes and mechanisms observed in zebrafish. This study specifies the benefits and drawbacks and future perspective of using zebrafish as a disease model. Abstract Diabetes mellitus (DM) is a complicated metabolic illness that has had a worldwide impact and placed an unsustainable load on both developed and developing countries’ health care systems. According to the International Diabetes Federation, roughly 537 million individuals had diabetes in 2021, with type 2 diabetes mellitus accounting for the majority of cases (T2DM). T2DM is a chronic illness defined by insufficient insulin production from pancreatic islet cells. T2DM generates various micro and macrovascular problems, with diabetic nephropathy (DN) being one of the most serious microvascular consequences, and which can lead to end-stage renal disease. The zebrafish (Danio rerio) has set the way for its future as a disease model organism. As numerous essential developmental processes, such as glucose metabolism and reactive metabolite production pathways, have been identified in zebrafish that are comparable to those seen in humans, it is a good model for studying diabetes and its consequences. It also has many benefits over other vertebrate models, including the permeability of its embryos to small compounds, disease-driven therapeutic target selection, in vivo validation, and deconstruction of biological networks. The organism can also be utilized to investigate and understand the genetic abnormalities linked to the onset of diabetes problems. Zebrafish may be used to examine and visualize the growth, morphology, and function of organs under normal physiological and diabetic settings. The zebrafish has become one of the most useful models for studying DN, especially when combined with genetic alterations and/or mutant or transgenic fish lines. The significant advancements of CRISPR and next-generation sequencing technology for disease modelling in zebrafish, as well as developments in molecular and nano technologies, have advanced the understanding of the molecular mechanisms of several human diseases, including DN. In this review, we emphasize the physiological and pathological processes relating to microvascular problems in zebrafish, as well as the many experimental zebrafish models used to research DN, and the DN-related outcomes and mechanisms observed in zebrafish.
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Gerstner L, Chen M, Kampf LL, Milosavljevic J, Lang K, Schneider R, Hildebrandt F, Helmstädter M, Walz G, Hermle T. Inhibition of endoplasmic reticulum stress signaling rescues cytotoxicity of human apolipoprotein-L1 risk variants in Drosophila. Kidney Int 2022; 101:1216-1231. [PMID: 35120995 PMCID: PMC10061223 DOI: 10.1016/j.kint.2021.12.031] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2021] [Revised: 12/10/2021] [Accepted: 12/23/2021] [Indexed: 01/01/2023]
Abstract
Risk variants of the apolipoprotein-L1 (APOL1) gene are associated with severe kidney disease, putting homozygous carriers at risk. Since APOL1 lacks orthologs in all major model organisms, a wide range of mechanisms frequently in conflict have been described for APOL1-associated nephropathies. The genetic toolkit in Drosophila allows unique in vivo insights into disrupted cellular homeostasis. To perform a mechanistic analysis, we expressed human APOL1 control and gain-of-function kidney risk variants in the podocyte-like garland cells of Drosophila nephrocytes and a wing precursor tissue. Expression of APOL1 risk variants was found to elevate endocytic function of garland cell nephrocytes that simultaneously showed early signs of cell death. Wild-type APOL1 had a significantly milder effect, while a control transgene with deletion of the short BH3 domain showed no overt phenotype. Nephrocyte endo-lysosomal function and slit diaphragm architecture remained unaffected by APOL1 risk variants, but endoplasmic reticulum (ER) swelling, chaperone induction, and expression of the reporter Xbp1-EGFP suggested an ER stress response. Pharmacological inhibition of ER stress diminished APOL1-mediated cell death and direct ER stress induction enhanced nephrocyte endocytic function similar to expression of APOL1 risk variants. We confirmed APOL1-dependent ER stress in the Drosophila wing precursor where silencing the IRE1-dependent branch of ER stress signaling by inhibition with Xbp1-RNAi abrogated cell death, representing the first rescue of APOL1-associated cytotoxicity in vivo. Thus, we uncovered ER stress as an essential consequence of APOL1 risk variant expression in vivo in Drosophila, suggesting a central role of this pathway in the pathogenesis of APOL1-associated nephropathies.
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Affiliation(s)
- Lea Gerstner
- Renal Division, Department of Medicine, Faculty of Medicine and Medical Center-University of Freiburg, Freiburg, Germany
| | - Mengmeng Chen
- Renal Division, Department of Medicine, Faculty of Medicine and Medical Center-University of Freiburg, Freiburg, Germany
| | - Lina L Kampf
- Renal Division, Department of Medicine, Faculty of Medicine and Medical Center-University of Freiburg, Freiburg, Germany
| | - Julian Milosavljevic
- Renal Division, Department of Medicine, Faculty of Medicine and Medical Center-University of Freiburg, Freiburg, Germany
| | - Konrad Lang
- Renal Division, Department of Medicine, Faculty of Medicine and Medical Center-University of Freiburg, Freiburg, Germany
| | - Ronen Schneider
- Renal Division, Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Friedhelm Hildebrandt
- Renal Division, Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Martin Helmstädter
- Renal Division, Department of Medicine, Faculty of Medicine and Medical Center-University of Freiburg, Freiburg, Germany
| | - Gerd Walz
- Renal Division, Department of Medicine, Faculty of Medicine and Medical Center-University of Freiburg, Freiburg, Germany; Signalling Research Centres BIOSS and CIBSS, University of Freiburg, Freiburg, Germany
| | - Tobias Hermle
- Renal Division, Department of Medicine, Faculty of Medicine and Medical Center-University of Freiburg, Freiburg, Germany.
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Chun J, Riella CV, Chung H, Shah SS, Wang M, Magraner JM, Ribas GT, Ribas HT, Zhang JY, Alper SL, Friedman DJ, Pollak MR. DGAT2 Inhibition Potentiates Lipid Droplet Formation To Reduce Cytotoxicity in APOL1 Kidney Risk Variants. J Am Soc Nephrol 2022; 33:889-907. [PMID: 35232775 PMCID: PMC9063887 DOI: 10.1681/asn.2021050723] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Accepted: 01/22/2022] [Indexed: 11/03/2022] Open
Abstract
BACKGROUND Two variants in the gene encoding apolipoprotein L1 (APOL1) that are highly associated with African ancestry are major contributors to the large racial disparity in rates of human kidney disease. We previously demonstrated that recruitment of APOL1 risk variants G1 and G2 from the endoplasmic reticulum to lipid droplets leads to reduced APOL1-mediated cytotoxicity in human podocytes. METHODS We used CRISPR-Cas9 gene editing of induced pluripotent stem cells to develop human-derived APOL1G0/G0 and APOL1G2/G2 kidney organoids on an isogenic background, and performed bulk RNA sequencing of organoids before and after treatment with IFN-γ. We examined the number and distribution of lipid droplets in response to treatment with inhibitors of diacylglycerol O-acyltransferases 1 and 2 (DGAT1 and DGAT2) in kidney cells and organoids. RESULTS APOL1 was highly upregulated in response to IFN-γ in human kidney organoids, with greater increases in organoids of high-risk G1 and G2 genotypes compared with wild-type (G0) organoids. RNA sequencing of organoids revealed that high-risk APOL1G2/G2 organoids exhibited downregulation of a number of genes involved in lipogenesis and lipid droplet biogenesis, as well as upregulation of genes involved in fatty acid oxidation. There were fewer lipid droplets in unstimulated high-risk APOL1G2/G2 kidney organoids than in wild-type APOL1G0/G0 organoids. Whereas DGAT1 inhibition reduced kidney organoid lipid droplet number, DGAT2 inhibition unexpectedly increased organoid lipid droplet number. DGAT2 inhibition promoted the recruitment of APOL1 to lipid droplets, with associated reduction in cytotoxicity. CONCLUSIONS Lipogenesis and lipid droplet formation are important modulators of APOL1-associated cytotoxicity. Inhibition of DGAT2 may offer a potential therapeutic strategy to attenuate cytotoxic effects of APOL1 risk variants.
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Affiliation(s)
- Justin Chun
- Department of Medicine, Division of Nephrology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts
- Department of Medicine, Division of Nephrology, University of Calgary, Cumming School of Medicine, Calgary, Alberta, Canada
| | - Cristian V. Riella
- Department of Medicine, Division of Nephrology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts
| | - Hyunjae Chung
- Department of Medicine, Division of Nephrology, University of Calgary, Cumming School of Medicine, Calgary, Alberta, Canada
| | - Shrijal S. Shah
- Department of Medicine, Division of Nephrology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts
| | - Minxian Wang
- Cardiovascular Disease Initiative and the Program in Medical and Population Genetics, Broad Institute of Harvard and Massachusetts Institute of Technology, Cambridge, Massachusetts
| | - Jose M. Magraner
- Department of Medicine, Division of Nephrology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts
| | - Guilherme T. Ribas
- Professional and Technological Education Sector, Federal University of Paraná, Curitiba, Paraná, Brazil
| | - Hennrique T. Ribas
- Professional and Technological Education Sector, Federal University of Paraná, Curitiba, Paraná, Brazil
| | - Jia-Yue Zhang
- Department of Medicine, Division of Nephrology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts
| | - Seth. L. Alper
- Department of Medicine, Division of Nephrology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts
| | - David J. Friedman
- Department of Medicine, Division of Nephrology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts
| | - Martin R. Pollak
- Department of Medicine, Division of Nephrology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts
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Daneshpajouhnejad P, Kopp JB, Winkler CA, Rosenberg AZ. The evolving story of apolipoprotein L1 nephropathy: the end of the beginning. Nat Rev Nephrol 2022; 18:307-320. [PMID: 35217848 PMCID: PMC8877744 DOI: 10.1038/s41581-022-00538-3] [Citation(s) in RCA: 34] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/14/2022] [Indexed: 01/13/2023]
Abstract
Genetic coding variants in APOL1, which encodes apolipoprotein L1 (APOL1), were identified in 2010 and are relatively common among individuals of sub-Saharan African ancestry. Approximately 13% of African Americans carry two APOL1 risk alleles. These variants, termed G1 and G2, are a frequent cause of kidney disease — termed APOL1 nephropathy — that typically manifests as focal segmental glomerulosclerosis and the clinical syndrome of hypertension and arterionephrosclerosis. Cell culture studies suggest that APOL1 variants cause cell dysfunction through several processes, including alterations in cation channel activity, inflammasome activation, increased endoplasmic reticulum stress, activation of protein kinase R, mitochondrial dysfunction and disruption of APOL1 ubiquitinylation. Risk of APOL1 nephropathy is mostly confined to individuals with two APOL1 risk variants. However, only a minority of individuals with two APOL1 risk alleles develop kidney disease, suggesting the need for a ‘second hit’. The best recognized factor responsible for this ‘second hit’ is a chronic viral infection, particularly HIV-1, resulting in interferon-mediated activation of the APOL1 promoter, although most individuals with APOL1 nephropathy do not have an obvious cofactor. Current therapies for APOL1 nephropathies are not adequate to halt progression of chronic kidney disease, and new targeted molecular therapies are in clinical trials. This Review summarizes current understanding of the role of APOL1 variants in kidney disease. The authors discuss the genetics, protein structure and biological functions of APOL1 variants and provide an overview of promising therapeutic strategies. In contrast to other APOL family members, which are primarily intracellular, APOL1 contains a unique secretory signal peptide, resulting in its secretion into plasma. APOL1 renal risk alleles provide protection from African human trypanosomiasis but are a risk factor for progressive kidney disease in those carrying two risk alleles. APOL1 risk allele frequency is ~35% in the African American population in the United States, with ~13% of individuals having two risk alleles; the highest allele frequencies are found in West African populations and their descendants. Cell and mouse models implicate endolysosomal and mitochondrial dysfunction, altered ion channel activity, altered autophagy, and activation of protein kinase R in the pathogenesis of APOL1-associated kidney disease; however, the relevance of these injury pathways to human disease has not been resolved. APOL1 kidney disease tends to be progressive, and current standard therapies are generally ineffective; targeted therapeutic strategies hold the most promise.
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Affiliation(s)
- Parnaz Daneshpajouhnejad
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD, USA.,Department of Pathology, University of Pennsylvania Hospital, Philadelphia, PA, USA
| | | | - Cheryl A Winkler
- Basic Research Program, Frederick National Laboratory for Cancer Research, Frederick, MD, USA
| | - Avi Z Rosenberg
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
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8
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Yoshida T, Latt KZ, Heymann J, Kopp JB. Lessons From APOL1 Animal Models. Front Med (Lausanne) 2021; 8:762901. [PMID: 34765626 PMCID: PMC8576052 DOI: 10.3389/fmed.2021.762901] [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: 08/23/2021] [Accepted: 09/30/2021] [Indexed: 11/13/2022] Open
Abstract
African-Americans have a three-fold higher rate of chronic kidney disease compared to European-Americans. Much of this excess risk is attributed to genetic variants in APOL1, encoding apolipoprotein L1, that are present only in individuals with sub-Saharan ancestry. Although 10 years have passed since the discovery of APOL1 renal risk variants, the mechanisms by which APOL1 risk allele gene products damage glomerular cells remain incompletely understood. Many mechanisms have been reported in cell culture models, but few have been demonstrated to be active in transgenic models. In this narrative review, we will review existing APOL1 transgenic models, from flies to fish to mice; discuss findings and limitations from studies; and consider future research directions.
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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 (NIH), Bethesda, MD, United States
| | - Khun Zaw Latt
- Kidney Disease Section, Kidney Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health (NIH), Bethesda, MD, United States
| | - Jurgen Heymann
- Kidney Disease Section, Kidney Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health (NIH), Bethesda, MD, United States
| | - Jeffrey B Kopp
- Kidney Disease Section, Kidney Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health (NIH), Bethesda, MD, United States
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9
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The Zebrafish Model to Understand Epigenetics in Renal Diseases. Int J Mol Sci 2021; 22:ijms22179152. [PMID: 34502062 PMCID: PMC8431166 DOI: 10.3390/ijms22179152] [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: 07/13/2021] [Revised: 08/22/2021] [Accepted: 08/23/2021] [Indexed: 11/24/2022] Open
Abstract
Epigenetic modifications are able to alter gene expression and include DNA methylation, different histone variants, and post-transcriptional modifications (PTMs), such as acetylation or phosphorylation, and through short/long RNAs, respectively. In this review, we focus on current knowledge concerning epigenetic modifications in gene regulation. We describe different forms of epigenetic modifications and explain how epigenetic changes can be detected. The relevance of epigenetics in renal diseases is highlighted with multiple examples and the use of the zebrafish model to study glomerular diseases in general and epigenetics in renal diseases in particular is discussed. We end with an outlook on how to use epigenetic modifications as a therapeutic target for different diseases. Here, the zebrafish model can be employed as a high-throughput screening tool not only to discover epigenetic alterations contributing to disease, but also to test novel substances that change epigenetic signatures in vivo. Therefore, the zebrafish model harbors the opportunity to find novel pathogenic pathways allowing a pre-selection of potential targets and compounds to be tested for renal diseases.
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10
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Madhavan SM, Buck M. The Relationship between APOL1 Structure and Function: Clinical Implications. KIDNEY360 2020; 2:134-140. [PMID: 35368828 PMCID: PMC8785724 DOI: 10.34067/kid.0002482020] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Accepted: 11/04/2020] [Indexed: 02/04/2023]
Abstract
Common variants in the APOL1 gene are associated with an increased risk of nondiabetic kidney disease in individuals of African ancestry. Mechanisms by which APOL1 variants mediate kidney disease pathogenesis are not well understood. Amino acid changes resulting from the kidney disease-associated APOL1 variants alter the three-dimensional structure and conformational dynamics of the C-terminal α-helical domain of the protein, which can rationalize the functional consequences. Understanding the three-dimensional structure of the protein, with and without the risk variants, can provide insights into the pathogenesis of kidney diseases mediated by APOL1 variants.
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Affiliation(s)
| | - Matthias Buck
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, Ohio
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11
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Scales SJ, Gupta N, De Mazière AM, Posthuma G, Chiu CP, Pierce AA, Hötzel K, Tao J, Foreman O, Koukos G, Oltrabella F, Klumperman J, Lin W, Peterson AS. Apolipoprotein L1-Specific Antibodies Detect Endogenous APOL1 inside the Endoplasmic Reticulum and on the Plasma Membrane of Podocytes. J Am Soc Nephrol 2020; 31:2044-2064. [PMID: 32764142 DOI: 10.1681/asn.2019080829] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2019] [Accepted: 05/10/2020] [Indexed: 12/29/2022] Open
Abstract
BACKGROUND APOL1 is found in human kidney podocytes and endothelia. Variants G1 and G2 of the APOL1 gene account for the high frequency of nondiabetic CKD among African Americans. Proposed mechanisms of kidney podocyte cytotoxicity resulting from APOL1 variant overexpression implicate different subcellular compartments. It is unclear where endogenous podocyte APOL1 resides, because previous immunolocalization studies utilized overexpressed protein or commercially available antibodies that crossreact with APOL2. This study describes and distinguishes the locations of both APOLs. METHODS Immunohistochemistry, confocal and immunoelectron microscopy, and podocyte fractionation localized endogenous and transfected APOL1 using a large panel of novel APOL1-specific mouse and rabbit monoclonal antibodies. RESULTS Both endogenous podocyte and transfected APOL1 isoforms vA and vB1 (and a little of isoform vC) localize to the luminal face of the endoplasmic reticulum (ER) and to the cell surface, but not to mitochondria, endosomes, or lipid droplets. In contrast, APOL2, isoform vB3, and most vC of APOL1 localize to the cytoplasmic face of the ER and are consequently absent from the cell surface. APOL1 knockout podocytes do not stain for APOL1, attesting to the APOL1-specificity of the antibodies. Stable re-transfection of knockout podocytes with inducible APOL1-G0, -G1, and -G2 showed no differences in localization among variants. CONCLUSIONS APOL1 is found in the ER and plasma membrane, consistent with either the ER stress or surface cation channel models of APOL1-mediated cytotoxicity. The surface localization of APOL1 variants potentially opens new therapeutic targeting avenues.
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Affiliation(s)
- Suzie J Scales
- Department of Molecular Biology, Genentech, South San Francisco, California .,Department of Immunology, Genentech, South San Francisco, California
| | - Nidhi Gupta
- Department of Molecular Biology, Genentech, South San Francisco, California.,Department of Immunology, Genentech, South San Francisco, California
| | - Ann M De Mazière
- Section of Cell Biology, Center for Molecular Medicine, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | - George Posthuma
- Section of Cell Biology, Center for Molecular Medicine, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Cecilia P Chiu
- Department of Antibody Engineering, Genentech, South San Francisco, California
| | - Andrew A Pierce
- Department of Pathology, Genentech, South San Francisco, California
| | - Kathy Hötzel
- Department of Pathology, Genentech, South San Francisco, California
| | - Jianhua Tao
- Department of Pathology, Genentech, South San Francisco, California
| | - Oded Foreman
- Department of Pathology, Genentech, South San Francisco, California
| | - Georgios Koukos
- Department of Molecular Biology, Genentech, South San Francisco, California
| | | | - Judith Klumperman
- Section of Cell Biology, Center for Molecular Medicine, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | - WeiYu Lin
- Department of Antibody Engineering, Genentech, South San Francisco, California
| | - Andrew S Peterson
- Department of Molecular Biology, Genentech, South San Francisco, California
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12
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Sayed AEDH, Kotb AM, Oda S, Kashiwada S, Mitani H. Protective effect of p53 knockout on 4-nonylphenol-induced nephrotoxicity in medaka (Oryzias latipes). CHEMOSPHERE 2019; 236:124314. [PMID: 31310970 DOI: 10.1016/j.chemosphere.2019.07.045] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2019] [Revised: 07/04/2019] [Accepted: 07/05/2019] [Indexed: 02/07/2023]
Abstract
In the past few decades, environmental pollutants have become common because of misused nonionic surfactants and detergents. Nonylphenol ethoxylates (NPs) are one of the most important contaminants of water. Therefore, the present study aimed to investigate the protective blocking effect of apoptosis (deficient P53 gene) on 4-nonylphenol (4-NP)-induced nephrotoxicity of medaka (Oryzias latipes). We divided 36 fish into six groups: two different control groups of wild type (Wt; Hd-rR) control and p53 (-/-) control, and four different treated with 4-nonylphenol (50 μg/L and 100 μg/L) for 15 days. Histology, immunochemistry, and TUNEL assays confirmed that 4-NP causes nephrotoxicity. Our results showed that 4-NP administration significantly disturbed the kidney structure and function and 4-NP-treated fish showed dilated glomerular vessels, had less glomerular cellular content, decreased expression of glomerular proteins, and an increased level of apoptosis compared with a Wt control group (P < 0.05). As p53 is an apoptotic inducer, some protection in p53-deficient medaka was found as nephrotoxic effects of 4-NP were minimized significantly. Our study demonstrated for the first time to our knowledge that 4-NP induces apoptosis, causing nephrotoxicity in medaka. We found that blocking apoptosis blocking was able to protect the kidney from the toxic effects of 4-NP.
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Affiliation(s)
- Alaa El-Din H Sayed
- Zoology Department, Faculty of Science, Assiut University, 71516, Assiut, Egypt.
| | - Ahmed M Kotb
- Department of Anatomy and Histology, Faculty of Veterinary Medicine, Assiut University, 71516 Assiut, Egypt
| | - Shoji Oda
- Department of Integrated Biosciences, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, Chiba 277-8562, Japan
| | - Shosaku Kashiwada
- Graduate School of Life Sciences, Toyo University, 1-1-1 Izumino, Itakura, Gunma 374-0193, Japan
| | - Hiroshi Mitani
- Department of Integrated Biosciences, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, Chiba 277-8562, Japan
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Abstract
Genetic variants in the APOL1 gene, found only in individuals of recent African ancestry, greatly increase risk of multiple types of kidney disease. These APOL1 kidney risk alleles are a rare example of genetic variants that are common but also have a powerful effect on disease susceptibility. These alleles rose to high frequency in sub-Saharan Africa because they conferred protection against pathogenic trypanosomes that cause African sleeping sickness. We consider the genetic evidence supporting the association between APOL1 and kidney disease across the range of clinical phenotypes in the APOL1 nephropathy spectrum. We then explore the origins of the APOL1 risk variants and evolutionary struggle between humans and trypanosomes at both the molecular and population genetic level. Finally, we survey the rapidly growing literature investigating APOL1 biology as elucidated from experiments in cell-based systems, cell-free systems, mouse and lower organism models of disease, and through illuminating natural experiments in humans.
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Affiliation(s)
- David J Friedman
- Division of Nephrology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts 02215, USA; ,
| | - Martin R Pollak
- Division of Nephrology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts 02215, USA; ,
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14
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Freedman BI, Limou S, Ma L, Kopp JB. APOL1-Associated Nephropathy: A Key Contributor to Racial Disparities in CKD. Am J Kidney Dis 2019; 72:S8-S16. [PMID: 30343724 DOI: 10.1053/j.ajkd.2018.06.020] [Citation(s) in RCA: 94] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2017] [Accepted: 06/25/2018] [Indexed: 01/09/2023]
Abstract
Genetic methodologies are improving our understanding of the pathophysiology in diverse diseases. Breakthroughs have been particularly impressive in nephrology, for which marked disparities exist in rates and etiologic classifications of end-stage kidney disease between African Americans and European Americans. Discovery of the apolipoprotein L1 gene (APOL1) association with focal segmental glomerulosclerosis, human immunodeficiency virus (HIV)-associated nephropathy, lupus nephritis, sickle cell nephropathy, and solidified glomerulosclerosis, as well as more rapid failure of transplanted kidneys from donors with APOL1 renal-risk genotypes, has improved our understanding of nondiabetic nephropathy. Environmental factors acting through natural selection in sub-Saharan African populations likely underlie this association. This article describes the discovery of chromosome 22q renal-risk variants and their worldwide distribution, reviews the epidemiology and pathology of APOL1-associated nephropathies, and explores several proposed mechanisms of kidney injury identified in cell culture and animal models. Detection of APOL1 associations with kidney diseases and delineation of injury pathways brings hope for effective treatment for these kidney diseases.
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Affiliation(s)
- Barry I Freedman
- Section on Nephrology, Department of Internal Medicine; Wake Forest School of Medicine, Winston-Salem, NC.
| | - Sophie Limou
- Centre de Recherche en Transplantation et Immunologie (CRTI) UMR1064, INSERM, Université de Nantes, Nantes, France; Institut de Transplantation Urologie et Néphrologie (ITUN), CHU Nantes, Nantes, France; Ecole Centrale de Nantes, Nantes, France
| | - Lijun Ma
- Section on Nephrology, Department of Internal Medicine; Wake Forest School of Medicine, Winston-Salem, NC
| | - Jeffrey B Kopp
- Kidney Disease Section, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD.
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15
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Abstract
The apolipoprotein L1 (APOL1) gene is unique to humans and gorillas and appeared ~33 million years ago. Since the majority of the mammals do not carry APOL1, it seems to be dispensable for kidney function. APOL1 renal risk variants (RRVs; G1 and G2) are associated with the development as well as progression of chronic kidney diseases (CKDs) at higher rates in populations with African ancestry. Cellular expression of two APOL1 RRVs has been demonstrated to induce cytotoxicity, including necrosis, apoptosis, and pyroptosis, in several cell types including podocytes; mechanistically, these toxicities were attributed to lysosomal swelling, K+ depletion, mitochondrial dysfunction, autophagy blockade, protein kinase receptor activation, ubiquitin D degradation, and endoplasmic reticulum stress; notably, these effects were found to be dose dependent and occurred only in overtly APOL1 RRV-expressing cells. However, cellular protein expressions as well as circulating blood levels of APOL1 RRVs were not elevated in patients suffering from APOL1 RRV-associated CKDs. Therefore, the question arises as to whether it is gain or loss of function on the part of APOL1 RRVs contributing to kidney cell injury. The question seems to be more pertinent after the recognition of the role of APOL1 nonrisk (G0) in the transition of parietal epithelial cells and preservation of the podocyte molecular phenotype through modulation of the APOL1-miR-193a axis. With this background, the present review analyzed the available literature in terms of the known function of APOL1 nonrisk and how the loss of these functions could have contributed to two APOL1 RRV-associated CKDs.
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Affiliation(s)
- Vinod Kumar
- Institute of Molecular Medicine, Feinstein Institute for Medical Research and Department of Medicine, Zucker School of Medicine at Hofstra-Northwell, Hempstead, New York
| | - Pravin C Singhal
- Institute of Molecular Medicine, Feinstein Institute for Medical Research and Department of Medicine, Zucker School of Medicine at Hofstra-Northwell, Hempstead, New York
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16
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RNA sequencing of isolated cell populations expressing human APOL1 G2 risk variant reveals molecular correlates of sickle cell nephropathy in zebrafish podocytes. PLoS One 2019; 14:e0217042. [PMID: 31158233 PMCID: PMC6546218 DOI: 10.1371/journal.pone.0217042] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2018] [Accepted: 05/05/2019] [Indexed: 12/04/2022] Open
Abstract
Kidney failure occurs in 5–13% of individuals with sickle cell disease and is associated with early mortality. Two APOL1 alleles (G1 and G2) have been identified as risk factors for sickle cell disease nephropathy. Both risk alleles are prevalent in individuals with recent African ancestry and have been associated with nephropathic complications in other diseases. Despite the association of G1 and G2 with kidney dysfunction, the mechanisms by which these variants contribute to increased risk remain poorly understood. Previous work in zebrafish models suggest that the G2 risk allele functions as a dominant negative, whereas the G1 allele is a functional null. To understand better the cellular pathology attributed to APOL1 G2, we investigated the in vivo effects of the G2 risk variant on distinct cell types using RNA sequencing. We surveyed APOL1 G2 associated transcriptomic alterations in podocytes and vascular endothelial cells isolated from zebrafish larvae expressing cell-type specific reporters. Our analysis identified many transcripts (n = 7,523) showing differential expression between APOL1 G0 (human wild-type) and APOL1 G2 exposed podocytes. Conversely, relatively few transcripts (n = 107) were differentially expressed when comparing APOL1 G0 and APOL1 G2 exposed endothelial cells. Pathway analysis of differentially expressed transcripts in podocytes showed enrichment for autophagy associated terms such as “Lysosome” and “Phagosome”, implicating these pathways in APOL1 G2 associated kidney dysfunction. This work provides insight into the molecular pathology of APOL1 G2 nephropathy which may offer new therapeutic strategies for multiple disease contexts such as sickle cell nephropathy.
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Outtandy P, Russell C, Kleta R, Bockenhauer D. Zebrafish as a model for kidney function and disease. Pediatr Nephrol 2019; 34:751-762. [PMID: 29502161 PMCID: PMC6424945 DOI: 10.1007/s00467-018-3921-7] [Citation(s) in RCA: 50] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Revised: 12/12/2017] [Accepted: 12/12/2017] [Indexed: 12/31/2022]
Abstract
Kidney disease is a global problem with around three million people diagnosed in the UK alone and the incidence is rising. Research is critical to develop better treatments. Animal models can help to better understand the pathophysiology behind the various kidney diseases and to screen for therapeutic compounds, but the use especially of mammalian models should be minimised in the interest of animal welfare. Zebrafish are increasingly used, as they are genetically tractable and have a basic renal anatomy comparable to mammalian kidneys with glomerular filtration and tubular filtration processing. Here, we discuss how zebrafish have advanced the study of nephrology and the mechanisms underlying kidney disease.
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Affiliation(s)
- Priya Outtandy
- Centre for Nephrology, Royal Free Hospital/Medical School, University College London, 1. Floor, Room 1.7007, Rowland Hill Street, London, NW3 2PF, UK
- Department of Comparative Biomedical Sciences, Royal Veterinary College, Royal College Street, London, NW1 0TU, UK
| | - Claire Russell
- Department of Comparative Biomedical Sciences, Royal Veterinary College, Royal College Street, London, NW1 0TU, UK
| | - Robert Kleta
- Centre for Nephrology, Royal Free Hospital/Medical School, University College London, 1. Floor, Room 1.7007, Rowland Hill Street, London, NW3 2PF, UK.
| | - Detlef Bockenhauer
- Centre for Nephrology, Royal Free Hospital/Medical School, University College London, 1. Floor, Room 1.7007, Rowland Hill Street, London, NW3 2PF, UK
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Kumar V, Paliwal N, Ayasolla K, Vashistha H, Jha A, Chandel N, Chowdhary S, Saleem MA, Malhotra A, Chander PN, Skorecki K, Singhal PC. Disruption of APOL1-miR193a Axis Induces Disorganization of Podocyte Actin Cytoskeleton. Sci Rep 2019; 9:3582. [PMID: 30837512 PMCID: PMC6401370 DOI: 10.1038/s41598-019-39376-y] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2018] [Accepted: 10/22/2018] [Indexed: 02/08/2023] Open
Abstract
APOL1-miR193a axis participates in the preservation of molecular phenotype of differentiated podocytes (DPDs). We examined the hypothesis that APOL1 (G0) preserves, but APOL1 risk alleles (G1 and G2) disrupt APOL1-miR193a axis in DPDs. DPDG0s displayed down-regulation of miR193a, but upregulation of nephrin expression. DPDG1s/G2s exhibited an increase in miR193a and down-regulation of the expression of adherens complex's constituents (CD2AP, nephrin, and dendrin). DPDG0s showed decreased Cathepsin L, enhanced dynamin expressions, and the intact actin cytoskeleton. On the contrary, DPDG1s/G2s displayed an increase in Cathepsin L, but down-regulation of dynamin expressions and disorganization of the actin cytoskeleton. APOL1 silencing enhanced miR193a and Cathepsin L, but down-regulated dynamin expressions. DPDG1s/G2s displayed nuclear import of dendrin, indicating an occurrence of destabilization of adherens complexes in APOL1 risk milieu. These findings suggest that DPDG1s and DPDG2s developed disorganized actin cytoskeleton as a consequence of disrupted APOL1-miR193a axis. Interestingly, docking and co-labeling studies suggested an interaction between APOL1 and CD2AP. APOL1G1/G1 and APOL1G1/G2 transgenic mice displayed nuclear import of dendrin indicating destabilization of adherens complexes in podocytes; moreover, these mice showed a four-fold increase in urinary albumin to creatinine ratio and development of focal segmental glomerular lesions.
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Affiliation(s)
- Vinod Kumar
- Immunology and Inflammation Center, Feinstein Institute for Medical Research and Zucker School of Medicine at Hofstra-Northwell, New York, USA
| | - Nitpriya Paliwal
- Immunology and Inflammation Center, Feinstein Institute for Medical Research and Zucker School of Medicine at Hofstra-Northwell, New York, USA
| | - Kamesh Ayasolla
- Immunology and Inflammation Center, Feinstein Institute for Medical Research and Zucker School of Medicine at Hofstra-Northwell, New York, USA
| | | | - Alok Jha
- Immunology and Inflammation Center, Feinstein Institute for Medical Research and Zucker School of Medicine at Hofstra-Northwell, New York, USA
| | - Nirupama Chandel
- Immunology and Inflammation Center, Feinstein Institute for Medical Research and Zucker School of Medicine at Hofstra-Northwell, New York, USA
| | - Sheetal Chowdhary
- Immunology and Inflammation Center, Feinstein Institute for Medical Research and Zucker School of Medicine at Hofstra-Northwell, New York, USA
| | | | - Ashwani Malhotra
- Immunology and Inflammation Center, Feinstein Institute for Medical Research and Zucker School of Medicine at Hofstra-Northwell, New York, USA
| | | | - Karl Skorecki
- Technion - Israel Institute of Technology, and Rambam Health Care Campus, Haifa, Israel
| | - Pravin C Singhal
- Immunology and Inflammation Center, Feinstein Institute for Medical Research and Zucker School of Medicine at Hofstra-Northwell, New York, USA.
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19
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Saleh A, Anwar MM, Zayed AE, Ezz Eldeen MES, Afifi G, Alnashiri HM, Gomaa AMS, Abd-Elkareem M, Abou-Elhamd AS, Shaheen ES, Mohamed GA, Hetta HF, Kotb AM. Impact of Ginkgo biloba extract and magnetized water on the survival rate and functional capabilities of pancreatic β-cells in type 2 diabetic rat model. Diabetes Metab Syndr Obes 2019; 12:1339-1347. [PMID: 31496771 PMCID: PMC6689767 DOI: 10.2147/dmso.s209856] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/24/2019] [Accepted: 07/16/2019] [Indexed: 12/15/2022] Open
Abstract
INTRODUCTION Type 2 diabetes (T2D) is a widely distributed disease that affects large population worldwide. This study aimed to verify the role of Ginkgo biloba (GB) extract and magnetized water (MW) on the survival rate and functional capabilities of pancreatic β-cells in type 2 diabetic rats. MATERIALS AND METHODS T2D was induced by feeding the rats on a high-fat diet (20% fat, 45% carbohydrate, 22% protein) for eight weeks followed by intra-peritoneal injection of a single low dose of streptozotocin (25mg/Kg). Forty rats were randomly assigned to four groups (n=10 rats) as follows: non treated control and three diabetic groups. One diabetic group served as a positive control (diabetic), while the other two groups were orally administered with water extract of GB leaves (0.11 g/kg/day) and MW (600 gauss) for four weeks, respectively. RESULTS The β-cell mass and insulin expression in these cells increased markedly after both treatments, particularly in GB treated group. In addition, the immune-expression of the two antioxidant enzymes; glutathione and superoxide dismutase 2 (SOD2) in the pancreatic tissue demonstrated a down-regulation in GB and MW treated groups as compared with the diabetic group. CONCLUSION A four-week treatment of GB and MW protected pancreatic β-cell cells and improved their insulin expression and antioxidant status in type 2 diabetic rats.
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Affiliation(s)
- Ahmed Saleh
- Department of Physics, Faculty of Science, Jazan University, Jazan, KSA
- Exploratory Center of Science and Technology
, Cairo, Egypt
| | - Mamdouh M Anwar
- Department of Pharmacology, Faculty of Pharmacy, Jazan University, Jazan, KSA
- Medical Physiology Department, Faculty of Medicine, Assiut University, Assiut, Egypt
| | - Ahmed E Zayed
- Department of Biology, Faculty of Science, Jazan University, Jazan, KSA
- Department of Anatomy and Histology, Faculty of Veterinary Medicine, Assiut University, Egypt
| | - Manal El Sayed Ezz Eldeen
- Endocrine Unit, Department of Internal Medicine, Faculty of Medicine, Assiut University, Assiut, Egypt
| | - Gamal Afifi
- Department of Physics, Faculty of Science, Jazan University, Jazan, KSA
- National Institute for Laser Enhanced Sciences, Cairo University
, Giza, Egypt
| | | | - Asmaa MS Gomaa
- Medical Physiology Department, Faculty of Medicine, Assiut University, Assiut, Egypt
| | - Mahmoud Abd-Elkareem
- Department of Anatomy and Histology, Faculty of Veterinary Medicine, Assiut University, Egypt
| | - Alaa Sayed Abou-Elhamd
- Department of Anatomy and Histology, Faculty of Veterinary Medicine, Assiut University, Egypt
- Department of Medical Laboratory Technology, Faculty of Applied Medical Sciences, Jazan University, Jazan, Saudi Arabia
| | | | - Ghada A Mohamed
- Endocrine Unit, Department of Internal Medicine, Faculty of Medicine, Assiut University, Assiut, Egypt
| | - Helal F Hetta
- Department of Medical Microbiology and Immunology, Faculty of Medicine, Assiut University, Assiut, Egypt
- Department of Internal Medicine, University of Cincinnati College of Medicine, Cincinnati, OH, USA
- Correspondence: Helal F HettaDepartment of Internal Medicine, University of Cincinnati College of Medicine, Cincinnati, 231 Albert B. Sabin Way, PO Box 670595, OH45267-0595, USAEmail
| | - Ahmed M Kotb
- Department of Anatomy and Histology, Faculty of Veterinary Medicine, Assiut University, Egypt
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20
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Elmonem MA, Berlingerio SP, van den Heuvel LP, de Witte PA, Lowe M, Levtchenko EN. Genetic Renal Diseases: The Emerging Role of Zebrafish Models. Cells 2018; 7:cells7090130. [PMID: 30200518 PMCID: PMC6162634 DOI: 10.3390/cells7090130] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2018] [Revised: 08/27/2018] [Accepted: 08/29/2018] [Indexed: 12/14/2022] Open
Abstract
The structural and functional similarity of the larval zebrafish pronephros to the human nephron, together with the recent development of easier and more precise techniques to manipulate the zebrafish genome have motivated many researchers to model human renal diseases in the zebrafish. Over the last few years, great advances have been made, not only in the modeling techniques of genetic diseases in the zebrafish, but also in how to validate and exploit these models, crossing the bridge towards more informative explanations of disease pathophysiology and better designed therapeutic interventions in a cost-effective in vivo system. Here, we review the significant progress in these areas giving special attention to the renal phenotype evaluation techniques. We further discuss the future applications of such models, particularly their role in revealing new genetic diseases of the kidney and their potential use in personalized medicine.
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Affiliation(s)
- Mohamed A Elmonem
- Department of Pediatric Nephrology & Development and Regeneration, University Hospitals Leuven, KU Leuven-University of Leuven, Herestraat 49, Box 817, 3000 Leuven, Belgium.
- Department of Clinical and Chemical Pathology, Faculty of Medicine, Cairo University, 11628 Cairo, Egypt.
| | - Sante Princiero Berlingerio
- Department of Pediatric Nephrology & Development and Regeneration, University Hospitals Leuven, KU Leuven-University of Leuven, Herestraat 49, Box 817, 3000 Leuven, Belgium.
| | - Lambertus P van den Heuvel
- Department of Pediatric Nephrology & Development and Regeneration, University Hospitals Leuven, KU Leuven-University of Leuven, Herestraat 49, Box 817, 3000 Leuven, Belgium.
- Department of Pediatric Nephrology, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands.
| | - Peter A de Witte
- Laboratory for Molecular Bio-Discovery, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven-University of Leuven, 3000 Leuven, Belgium.
| | - Martin Lowe
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester M13 9PL, UK.
| | - Elena N Levtchenko
- Department of Pediatric Nephrology & Development and Regeneration, University Hospitals Leuven, KU Leuven-University of Leuven, Herestraat 49, Box 817, 3000 Leuven, Belgium.
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21
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Endlich N, Lange T, Kuhn J, Klemm P, Kotb AM, Siegerist F, Kindt F, Lindenmeyer MT, Cohen CD, Kuss AW, Nath N, Rettig R, Lendeckel U, Zimmermann U, Amann K, Stracke S, Endlich K. BDNF: mRNA expression in urine cells of patients with chronic kidney disease and its role in kidney function. J Cell Mol Med 2018; 22:5265-5277. [PMID: 30133147 PMCID: PMC6201371 DOI: 10.1111/jcmm.13762] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2017] [Accepted: 05/30/2018] [Indexed: 12/21/2022] Open
Abstract
Podocyte loss and changes to the complex morphology are major causes of chronic kidney disease (CKD). As the incidence is continuously increasing over the last decades without sufficient treatment, it is important to find predicting biomarkers. Therefore, we measured urinary mRNA levels of podocyte genes NPHS1, NPHS2, PODXL and BDNF, KIM‐1, CTSL by qRT‐PCR of 120 CKD patients. We showed a strong correlation between BDNF and the kidney injury marker KIM‐1, which were also correlated with NPHS1, suggesting podocytes as a contributing source. In human biopsies, BDNF was localized in the cell body and major processes of podocytes. In glomeruli of diabetic nephropathy patients, we found a strong BDNF signal in the remaining podocytes. An inhibition of the BDNF receptor TrkB resulted in enhanced podocyte dedifferentiation. The knockdown of the orthologue resulted in pericardial oedema formation and lowered viability of zebrafish larvae. We found an enlarged Bowman's space, dilated glomerular capillaries, podocyte loss and an impaired glomerular filtration. We demonstrated that BDNF is essential for glomerular development, morphology and function and the expression of BDNF and KIM‐1 is highly correlated in urine cells of CKD patients. Therefore, BDNF mRNA in urine cells could serve as a potential CKD biomarker.
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Affiliation(s)
- Nicole Endlich
- Department of Anatomy and Cell Biology, University Medicine Greifswald, Greifswald, Germany
| | - Tim Lange
- Department of Anatomy and Cell Biology, University Medicine Greifswald, Greifswald, Germany
| | - Jana Kuhn
- Department of Anatomy and Cell Biology, University Medicine Greifswald, Greifswald, Germany.,Clinic for Diabetes and Metabolic Diseases, Karlsburg Hospital Dr. Guth GmbH & Co KG, Karlsburg, Germany
| | - Paul Klemm
- Department of Anatomy and Cell Biology, University Medicine Greifswald, Greifswald, Germany
| | - Ahmed M Kotb
- Department of Anatomy and Cell Biology, University Medicine Greifswald, Greifswald, Germany
| | - Florian Siegerist
- Department of Anatomy and Cell Biology, University Medicine Greifswald, Greifswald, Germany
| | - Frances Kindt
- Department of Anatomy and Cell Biology, University Medicine Greifswald, Greifswald, Germany
| | - Maja T Lindenmeyer
- Nephrological Center, Medical Clinic and Policlinic IV, University of Munich, Munich, Germany
| | - Clemens D Cohen
- Nephrological Center, Medical Clinic and Policlinic IV, University of Munich, Munich, Germany
| | - Andreas W Kuss
- Department of Functional Genomics, University Medicine Greifswald, Greifswald, Germany
| | - Neetika Nath
- Institute of Bioinformatics, University of Greifswald, Greifswald, Germany
| | - Rainer Rettig
- Department of Physiology, University of Greifswald, Karlsburg, Germany
| | - Uwe Lendeckel
- Department of Medical Biochemistry and Molecular Biology, University Medicine Greifswald, Greifswald, Germany
| | - Uwe Zimmermann
- Department of Urology, University Medicine Greifswald, Greifswald, Germany
| | - Kerstin Amann
- Department of Pathology, University of Erlangen-Nürnberg, Erlangen, Germany
| | - Sylvia Stracke
- Department of Internal Medicine A, University Medicine Greifswald, Greifswald, Germany
| | - Karlhans Endlich
- Department of Anatomy and Cell Biology, University Medicine Greifswald, Greifswald, Germany
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22
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Siegerist F, Endlich K, Endlich N. Novel Microscopic Techniques for Podocyte Research. Front Endocrinol (Lausanne) 2018; 9:379. [PMID: 30050501 PMCID: PMC6050355 DOI: 10.3389/fendo.2018.00379] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Accepted: 06/22/2018] [Indexed: 01/16/2023] Open
Abstract
Together with endothelial cells and the glomerular basement membrane, podocytes form the size-specific filtration barrier of the glomerulus with their interdigitating foot processes. Since glomerulopathies are associated with so-called foot process effacement-a severe change of well-formed foot processes into flat and broadened processes-visualization of the three-dimensional podocyte morphology is a crucial part for diagnosis of nephrotic diseases. However, interdigitating podocyte foot processes are too narrow to be resolved by classic light microscopy due to Ernst Abbe's law making electron microscopy necessary. Although three dimensional electron microscopy approaches like serial block face and focused ion beam scanning electron microscopy and electron tomography allow volumetric reconstruction of podocytes, these techniques are very time-consuming and too specialized for routine use or screening purposes. During the last few years, different super-resolution microscopic techniques were developed to overcome the optical resolution limit enabling new insights into podocyte morphology. Super-resolution microscopy approaches like three dimensional structured illumination microscopy (3D-SIM), stimulated emission depletion microscopy (STED) and localization microscopy [stochastic optical reconstruction microscopy (STORM), photoactivated localization microscopy (PALM)] reach resolutions down to 80-20 nm and can be used to image and further quantify podocyte foot process morphology. Furthermore, in vivo imaging of podocytes is essential to study the behavior of these cells in situ. Therefore, multiphoton laser microscopy was a breakthrough for in vivo studies of podocytes in transgenic animal models like rodents and zebrafish larvae because it allows imaging structures up to several hundred micrometer in depth within the tissue. Additionally, along with multiphoton microscopy, lightsheet microscopy is currently used to visualize larger tissue volumes and therefore image complete glomeruli in their native tissue context. Alongside plain visualization of cellular structures, atomic force microscopy has been used to study the change of mechanical properties of podocytes in diseased states which has been shown to be a culprit in podocyte maintenance. This review discusses recent advances in the field of microscopic imaging and demonstrates their currently used and other possible applications for podocyte research.
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Affiliation(s)
| | | | - Nicole Endlich
- Institute for Anatomy and Cell Biology, University Medicine Greifswald, Greifswald, Germany
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23
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Abstract
The association of variants in the APOL1 gene, which encodes apolipoprotein L1 (APOL1), with progressive nondiabetic kidney diseases in African Americans has prompted intense investigation into the function(s) of APOL1. APOL1 is an innate immune effector that protects human beings from infection by some trypanosomal parasites. We review the data characterizing APOL1 trypanolytic function, which has been a basis for studies of APOL1 function in mammalian cells. Subsequently, we discuss the studies that use animal models, mammalian cell culture models, and kidney biopsy tissue to discover the mechanisms of variant APOL1-associated kidney diseases.
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24
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Protective Effect of Ginkgo biloba and Magnetized Water on Nephropathy in Induced Type 2 Diabetes in Rat. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2018; 2018:1785614. [PMID: 29991974 PMCID: PMC6016160 DOI: 10.1155/2018/1785614] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/13/2018] [Revised: 04/22/2018] [Accepted: 05/02/2018] [Indexed: 12/16/2022]
Abstract
We aimed in our current study to explore the protective effect of Ginkgo biloba (GB) and magnetized water (MW) against nephrotoxicity associating induced type 2 diabetes mellitus in rat. Here, we induced diabetes by feeding our lab rats on a high fat-containing diet (4 weeks) and after that injecting them with streptozotocin (STZ). We randomly divided forty rats into four different groups: nontreated control (Ctrl), nontreated diabetic (Diabetic), Diabetic+GB (4-week treatment), and Diabetic+MW (4-week treatment). After the experiment was finished, serum and kidney tissue samples were gathered. Blood levels of glucose, triglycerides, cholesterol, creatinine, and urea were markedly elevated in the diabetic group than in the control group. In all animals treated with GB and MW, the levels of urea, creatinine, and glucose were significantly reduced (all P < 0.01). GB and MW attenuated glomerular and tubular injury as well as the histological score. Furthermore, they normalized the contents of glutathione reductase and SOD2. In summary, our data showed that GB and MW treatment protected type 2 diabetic rat kidneys from nephrotoxic damages by reducing the hyperlipidemia, uremia, oxidative stress, and renal dysfunction.
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25
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APOL1: The Balance Imposed by Infection, Selection, and Kidney Disease. Trends Mol Med 2018; 24:682-695. [PMID: 29886044 DOI: 10.1016/j.molmed.2018.05.008] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2018] [Revised: 05/07/2018] [Accepted: 05/14/2018] [Indexed: 02/07/2023]
Abstract
Chronic kidney disease (CKD) affects millions of people and constitutes a major health and financial burden worldwide. People of African descent are at an increased risk of developing kidney disease, which is mostly explained by two variants in the Apolipoprotein L1 (APOL1) gene that are found only in people of west African origin. It is hypothesized that these variants were genetically selected due to the protection they afford against African sleeping sickness, caused by the parasite Trypanosoma brucei. Targeting mutant APOL1 could have substantial therapeutic potential for treating kidney disease. In this review, we will describe the intriguing interplay between microbiology, genetics, and kidney disease as revealed in APOL1-associated kidney disease, discuss APOL1-induced cytotoxicity and its therapeutic implications.
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26
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Artelt N, Ludwig TA, Rogge H, Kavvadas P, Siegerist F, Blumenthal A, van den Brandt J, Otey CA, Bang ML, Amann K, Chadjichristos CE, Chatziantoniou C, Endlich K, Endlich N. The Role of Palladin in Podocytes. J Am Soc Nephrol 2018; 29:1662-1678. [PMID: 29720549 DOI: 10.1681/asn.2017091039] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Accepted: 03/28/2018] [Indexed: 11/03/2022] Open
Abstract
Background Podocyte loss and effacement of interdigitating podocyte foot processes are the major cause of a leaky filtration barrier and ESRD. Because the complex three-dimensional morphology of podocytes depends on the actin cytoskeleton, we studied the role in podocytes of the actin bundling protein palladin, which is highly expressed therein.Methods We knocked down palladin in cultured podocytes by siRNA transfection or in zebrafish embryos by morpholino injection and studied the effects by immunofluorescence and live imaging. We also investigated kidneys of mice with podocyte-specific knockout of palladin (PodoPalld-/- mice) by immunofluorescence and ultrastructural analysis and kidney biopsy specimens from patients by immunostaining for palladin.Results Compared with control-treated podocytes, palladin-knockdown podocytes had reduced actin filament staining, smaller focal adhesions, and downregulation of the podocyte-specific proteins synaptopodin and α-actinin-4. Furthermore, palladin-knockdown podocytes were more susceptible to disruption of the actin cytoskeleton with cytochalasin D, latrunculin A, or jasplakinolide and showed altered migration dynamics. In zebrafish embryos, palladin knockdown compromised the morphology and dynamics of epithelial cells at an early developmental stage. Compared with PodoPalld+/+ controls, PodoPalld-/- mice developed glomeruli with a disturbed morphology, an enlarged subpodocyte space, mild effacement, and significantly reduced expression of nephrin and vinculin. Furthermore, nephrotoxic serum injection led to significantly higher levels of proteinuria in PodoPalld-/- mice than in controls. Kidney biopsy specimens from patients with diabetic nephropathy and FSGS showed downregulation of palladin in podocytes as well.Conclusions Palladin has an important role in podocyte function in vitro and in vivo.
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Affiliation(s)
| | | | | | - Panagiotis Kavvadas
- National Institute for Health and Medical Research (INSERM), Unité Mixte de Recherche (UMR)-S1155, Tenon Hospital, Sorbonne Universités, Paris, France
| | | | | | - Jens van den Brandt
- Central Core and Research Facility of Laboratory Animals (ZSFV), University Medicine Greifswald, Greifswald, Germany
| | - Carol A Otey
- Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill (UNC), Chapel Hill, North Carolina
| | - Marie-Louise Bang
- Institute of Genetic and Biomedical Research, UOS Milan, National Research Council, Milan, Italy.,Humanitas Clinical and Research Center, Rozzano, Milan, Italy; and
| | - Kerstin Amann
- Department of Nephropathology, University Medicine Erlangen, Erlangen, Germany
| | - Christos E Chadjichristos
- National Institute for Health and Medical Research (INSERM), Unité Mixte de Recherche (UMR)-S1155, Tenon Hospital, Sorbonne Universités, Paris, France
| | - Christos Chatziantoniou
- National Institute for Health and Medical Research (INSERM), Unité Mixte de Recherche (UMR)-S1155, Tenon Hospital, Sorbonne Universités, Paris, France
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27
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Kotb AM, Abd-Elkareem M, Abou Khalil NS, Sayed AEDH. Protective effect of Nigella sativa on 4-nonylphenol-induced nephrotoxicity in Clarias gariepinus (Burchell, 1822). THE SCIENCE OF THE TOTAL ENVIRONMENT 2018; 619-620:692-699. [PMID: 29156287 DOI: 10.1016/j.scitotenv.2017.11.131] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2017] [Revised: 10/26/2017] [Accepted: 11/11/2017] [Indexed: 02/07/2023]
Abstract
The aim of this study was to examine the protective effects of Nigella sativa (N. sativa) on 4-Nonylphenol-induced nephrotoxicity in Clarias gariepinus. 30 fishes were divided into five groups: control, 4-nonylphenol-treated, 1% N. sativa treated, 2.5% N. sativa treated, and 5% N. sativa treated. N. sativa and 4-Nonylphenol were given for 3weeks. 4-NP and 4-NP-N. sativa treated fishes were compared with the control group. Kidney histology, immunochemistry, and electron microscope were assessed after 4-NP exposure. In the African catfish, 4-NP is mainly excreted through the kidney causing nephrotoxicity. Our results showed that 4-NP administration significantly disturbed the kidney structure and function. 4-NP treated fishes showed dilated glomerular vessels, fewer glomerular cells content, decreased expressions of glomerular proteins, and increased level of autophagy compared to control group (P<0.05). As N. sativa has different immunological and pharmacological effects such as anti-apoptotic and anti-oxidant, therefore, the administration of N. sativa with 4-Nonylphenol significantly minimize the nephrotoxic effect of 4-NP and maintain the normal kidney structure and function. Our novel study demonstrated for the first time that N. sativa could protect the kidney against 4-NP induced-nephrotoxicity.
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Affiliation(s)
- Ahmed M Kotb
- Department of Anatomy and Histology, Faculty of Veterinary Medicine, Assiut University, 71516 Assiut, Egypt
| | - Mahmoud Abd-Elkareem
- Department of Anatomy and Histology, Faculty of Veterinary Medicine, Assiut University, 71516 Assiut, Egypt
| | - Nasser S Abou Khalil
- Medical Physiology Department, Faculty of Medicine, Assiut University, Assiut, Egypt
| | - Alaa El-Din H Sayed
- Zoology department, Faculty of Science, Assiut University, 71516 Assiut, Egypt; Department of Integrated Biosciences, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, Chiba 277-8562, Japan.
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28
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Fu SM, Wang H, Dai C, Sung SSJ, Gaskin F. Pathogenesis of proliferative lupus nephritis from a historical and personal perspective. Clin Immunol 2017; 185:51-58. [PMID: 27591148 PMCID: PMC5332347 DOI: 10.1016/j.clim.2016.07.024] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2016] [Revised: 07/25/2016] [Accepted: 07/26/2016] [Indexed: 01/27/2023]
Affiliation(s)
- Shu Man Fu
- Division of Rheumatology, The Center of Inflammation, Immunity and Regenerative Medicine and Division of Nephrology, Department of Medicine, University of Virginia, Charlottesville, VA, United States; Department of Microbiology, Immunology and Cancer Biology, University of Virginia, Charlottesville, VA, United States.
| | - Hongyang Wang
- Division of Rheumatology, The Center of Inflammation, Immunity and Regenerative Medicine and Division of Nephrology, Department of Medicine, University of Virginia, Charlottesville, VA, United States
| | - Chao Dai
- Division of Rheumatology, The Center of Inflammation, Immunity and Regenerative Medicine and Division of Nephrology, Department of Medicine, University of Virginia, Charlottesville, VA, United States
| | - Sun-Sang J Sung
- Division of Rheumatology, The Center of Inflammation, Immunity and Regenerative Medicine and Division of Nephrology, Department of Medicine, University of Virginia, Charlottesville, VA, United States
| | - Felicia Gaskin
- Department of Psychiatry and Neurobehavioral Sciences, University of Virginia, Charlottesville, VA, United States
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29
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O'Toole JF, Schilling W, Kunze D, Madhavan SM, Konieczkowski M, Gu Y, Luo L, Wu Z, Bruggeman LA, Sedor JR. ApoL1 Overexpression Drives Variant-Independent Cytotoxicity. J Am Soc Nephrol 2017; 29:869-879. [PMID: 29180397 DOI: 10.1681/asn.2016121322] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2016] [Accepted: 10/31/2017] [Indexed: 12/16/2022] Open
Abstract
Coding variants in the APOL1 gene are associated with kidney diseases in African ancestral populations; yet, the underlying biologic mechanisms remain uncertain. Variant-dependent autophagic and cytotoxic cell death have been proposed as pathogenic pathways mediating kidney injury. To examine this possibility, we conditionally expressed APOL1-G0 (reference), -G1, and -G2 (variants) using a tetracycline-regulated system in HEK293 cells. Autophagy was monitored biochemically and cell death was measured using multiple assays. We measured intracellular Na+ and K+ content with atomic absorption spectroscopy and APOL1-dependent currents with whole-cell patch clamping. Neither reference nor variant APOL1s induced autophagy. At high expression levels, APOL1-G0, -G1, and -G2 inserted into the plasma membrane and formed pH-sensitive cation channels, causing collapse of cellular Na+ and K+ gradients, phosphorylation of p38 mitogen-activated protein kinase, and cell death, without variant-dependent differences. APOL1-G0 and -G2 exhibited similar channel properties in whole-cell patch clamp experiments. At low expression levels, neither reference nor variant APOL1s localized on the plasma membrane, Na+ and K+ gradients were maintained, and cells remained viable. Our results indicate that APOL1-mediated pore formation is critical for the trypanolytic activity of APOL1 and drives APOL1-mediated cytotoxicity in overexpression systems. The absence of cytotoxicity at physiologic expression levels suggests variant-dependent intracellular K+ loss and cytotoxicity does not drive kidney disease progression.
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Affiliation(s)
- John F O'Toole
- Department of Nephrology and Hypertension, Glickman Urological and Kidney Institute, Cleveland Clinic, Cleveland, Ohio.,Department of Pathobiology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio.,Department of Molecular Medicine, Cleveland Clinic Lerner College of Medicine, Case Western Reserve University, Cleveland, Ohio; and
| | - William Schilling
- Rammelkamp Center, MetroHealth System.,Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, Ohio
| | | | | | | | - Yaping Gu
- Department of Pathobiology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio
| | - Liping Luo
- Department of Pathobiology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio
| | - Zhenzhen Wu
- Department of Pathobiology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio
| | - Leslie A Bruggeman
- Department of Nephrology and Hypertension, Glickman Urological and Kidney Institute, Cleveland Clinic, Cleveland, Ohio.,Department of Pathobiology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio.,Department of Molecular Medicine, Cleveland Clinic Lerner College of Medicine, Case Western Reserve University, Cleveland, Ohio; and
| | - John R Sedor
- Department of Nephrology and Hypertension, Glickman Urological and Kidney Institute, Cleveland Clinic, Cleveland, Ohio.,Department of Pathobiology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio.,Department of Molecular Medicine, Cleveland Clinic Lerner College of Medicine, Case Western Reserve University, Cleveland, Ohio; and.,Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, Ohio
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30
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Tomas NM, Meyer-Schwesinger C, von Spiegel H, Kotb AM, Zahner G, Hoxha E, Helmchen U, Endlich N, Koch-Nolte F, Stahl RAK. A Heterologous Model of Thrombospondin Type 1 Domain-Containing 7A-Associated Membranous Nephropathy. J Am Soc Nephrol 2017; 28:3262-3277. [PMID: 28814510 DOI: 10.1681/asn.2017010030] [Citation(s) in RCA: 63] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2017] [Accepted: 05/25/2017] [Indexed: 11/03/2022] Open
Abstract
Thrombospondin type 1 domain-containing 7A (THSD7A) is a target for autoimmunity in patients with membranous nephropathy (MN). Circulating autoantibodies from patients with THSD7A-associated MN have been demonstrated to cause MN in mice. However, THSD7A-associated MN is a rare disease, preventing the use of patient antibodies for larger experimental procedures. Therefore, we generated antibodies against the human and mouse orthologs of THSD7A in rabbits by coimmunization with the respective cDNAs. Injection of these anti-THSD7A antibodies into mice induced a severe nephrotic syndrome with proteinuria, weight gain, and hyperlipidemia. Immunofluorescence analyses revealed granular antigen-antibody complexes in a subepithelial location along the glomerular filtration barrier 14 days after antibody injection, and immunohistochemistry for rabbit IgG and THSD7A as well as ultrastructural analyses showed the typical characteristics of human MN. Mice injected with purified IgG from rabbit serum that was taken before immunization failed to develop any of these changes. Notably, MN developed in the absence of detectable complement activation, and disease was strain dependent. In vitro, anti-THSD7A antibodies caused cytoskeletal rearrangement and activation of focal adhesion signaling. Knockdown of the THSD7A ortholog, thsd7aa, in zebrafish larvae resulted in altered podocyte differentiation and impaired glomerular filtration barrier function, with development of pericardial edema, suggesting an important role of THSD7A in glomerular filtration barrier integrity. In summary, our study introduces a heterologous mouse model that allows further investigation of the molecular events that underlie MN.
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Affiliation(s)
| | | | | | - Ahmed M Kotb
- Institute of Anatomy and Cell Biology, University Medicine Greifswald, Greifswald, Germany; and.,Department of Anatomy and Histology, Faculty of Veterinary Medicine, Assiut University, Assiut, Egypt
| | | | | | | | - Nicole Endlich
- Institute of Anatomy and Cell Biology, University Medicine Greifswald, Greifswald, Germany; and
| | - Friedrich Koch-Nolte
- Institute of Immunology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
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31
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Rubinow KB, Henderson CM, Robinson-Cohen C, Himmelfarb J, de Boer IH, Vaisar T, Kestenbaum B, Hoofnagle AN. Kidney function is associated with an altered protein composition of high-density lipoprotein. Kidney Int 2017; 92:1526-1535. [PMID: 28754556 DOI: 10.1016/j.kint.2017.05.020] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Revised: 05/16/2017] [Accepted: 05/18/2017] [Indexed: 12/28/2022]
Abstract
Patients with chronic kidney disease (CKD) exhibit a myriad of metabolic derangements, including dyslipidemia characterized by low plasma concentrations of high-density lipoprotein (HDL)-associated cholesterol. However, the effects of kidney disease on HDL composition have not been comprehensively determined. Here we used a targeted mass spectrometric approach to quantify 38 proteins contained in the HDL particles within a CKD cohort of 509 participants with a broad range of estimated glomerular filtration rates (eGFRs) (CKD stages I-V, and a mean eGFR of 45.5 mL/min/1.73m2). After adjusting for multiple testing, demographics, comorbidities, medications, and other characteristics, eGFR was significantly associated with differences in four HDL proteins. Compared to participants with an eGFR of 60 mL/min/1.73m2 or more, those with an eGFR under 15 mL/min/1.73m2 exhibited 1.89-fold higher retinol-binding protein 4 (95% confidence interval 1.34-2.67), 1.52-fold higher apolipoprotein C-III (1.25-1.84), 0.70-fold lower apolipoprotein L1 (0.55-0.92), and 0.64-fold lower vitronectin (0.48-0.85). Although the HDL apolipoprotein L1 was slightly lower among African Americans than among Caucasian individuals, the relationship to eGFR did not differ by race. After adjustment, no HDL-associated proteins associated with albuminuria. Thus, modest changes in the HDL proteome provide preliminary evidence for an association between HDL proteins and declining kidney function, but this needs to be replicated. Future analyses will determine if HDL proteomics is indeed a clinical predictor of declining kidney function or cardiovascular outcomes.
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Affiliation(s)
- Katya B Rubinow
- Department of Medicine, University of Washington, Seattle, Washington, USA
| | - Clark M Henderson
- Department of Laboratory Medicine, University of Washington, Seattle, Washington, USA
| | - Cassianne Robinson-Cohen
- Department of Medicine, University of Washington, Seattle, Washington, USA; Kidney Research Institute, University of Washington, Seattle, Washington, USA
| | - Jonathan Himmelfarb
- Department of Medicine, University of Washington, Seattle, Washington, USA; Kidney Research Institute, University of Washington, Seattle, Washington, USA
| | - Ian H de Boer
- Department of Medicine, University of Washington, Seattle, Washington, USA; Kidney Research Institute, University of Washington, Seattle, Washington, USA
| | - Tomas Vaisar
- Department of Medicine, University of Washington, Seattle, Washington, USA
| | - Bryan Kestenbaum
- Department of Medicine, University of Washington, Seattle, Washington, USA; Kidney Research Institute, University of Washington, Seattle, Washington, USA
| | - Andrew N Hoofnagle
- Department of Medicine, University of Washington, Seattle, Washington, USA; Department of Laboratory Medicine, University of Washington, Seattle, Washington, USA; Kidney Research Institute, University of Washington, Seattle, Washington, USA.
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32
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Madhavan SM, O'Toole JF, Konieczkowski M, Barisoni L, Thomas DB, Ganesan S, Bruggeman LA, Buck M, Sedor JR. APOL1 variants change C-terminal conformational dynamics and binding to SNARE protein VAMP8. JCI Insight 2017; 2:92581. [PMID: 28724794 DOI: 10.1172/jci.insight.92581] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2017] [Accepted: 06/13/2017] [Indexed: 12/11/2022] Open
Abstract
APOL1 variants in African populations mediate resistance to trypanosomal infection but increase risk for kidney diseases through unknown mechanisms. APOL1 is expressed in glomerular podocytes and does not vary with underlying kidney disease diagnoses or APOL1 genotypes, suggesting that the kidney disease-associated variants dysregulate its function rather than its localization or abundance. Structural homology searches identified vesicle-associated membrane protein 8 (VAMP8) as an APOL1 protein interactor. VAMP8 colocalizes with APOL1 in the podocyte, and the APOL1:VAMP8 interaction was confirmed biochemically and with surface plasmon resonance. APOL1 variants attenuate this interaction. Computational modeling of APOL1's 3-dimensional structure, followed by molecular dynamics simulations, revealed increased motion of the C-terminal domain of reference APOL1 compared with either variant, suggesting that the variants stabilize a closed or autoinhibited state that diminishes protein interactions with VAMP8. Changes in ellipticity with increasing urea concentrations, as assessed by circular dichroism spectroscopy, showed higher conformational stability of the C-terminal helix of the variants compared with the reference protein. These results suggest that reference APOL1 interacts with VAMP8-coated vesicles, a process attenuated by variant-induced reduction in local dynamics of the C-terminal. Disordered vesicular trafficking in the podocyte may cause injury and progressive chronic kidney diseases in susceptible African Americans subjects.
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Affiliation(s)
- Sethu M Madhavan
- Department of Medicine and Rammelkamp Center for Education and Research, MetroHealth System Campus, and
| | - John F O'Toole
- Department of Medicine and Rammelkamp Center for Education and Research, MetroHealth System Campus, and
| | - Martha Konieczkowski
- Department of Medicine and Rammelkamp Center for Education and Research, MetroHealth System Campus, and
| | - Laura Barisoni
- Department of Pathology, University of Miami, Miami, Florida, USA
| | - David B Thomas
- Department of Pathology, University of Miami, Miami, Florida, USA
| | | | - Leslie A Bruggeman
- Department of Medicine and Rammelkamp Center for Education and Research, MetroHealth System Campus, and
| | - Matthias Buck
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, Ohio, USA
| | - John R Sedor
- Department of Medicine and Rammelkamp Center for Education and Research, MetroHealth System Campus, and.,Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, Ohio, USA
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Kormann R, Jannot AS, Narjoz C, Ribeil JA, Manceau S, Delville M, Joste V, Prié D, Pouchot J, Thervet E, Courbebaisse M, Arlet JB. Roles of APOL1 G1 and G2 variants in sickle cell disease patients: kidney is the main target. Br J Haematol 2017; 179:323-335. [PMID: 28699644 DOI: 10.1111/bjh.14842] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2017] [Accepted: 05/28/2017] [Indexed: 12/29/2022]
Abstract
In African-American patients with sickle cell disease (SCD), APOL1 G1 and G2 variants are associated with increased risk of sickle cell nephropathy (SCN). To determine the role of APOL1 variants in SCD patients living in Europe, we genotyped 152 SCD patients [aged 30·4 (24·3-36·4) years], mainly of Sub-Saharan African ancestry, for APOL1 G1 and G2 and for variants of four genes with kidney tropism (GSTM1, GSTT1, GSTP1, and HMOX1). Homozygous or double-heterozygous APOL G1 and G2 genotypes were strongly associated with end stage renal disease (P = 0·003) and worse Kidney Disease: Improving Global Outcomes stages (P = 0·001). Further, these genotypes were associated in an age-dependent manner with lower estimated glomerular filtration rate (eGFR, P = 0·008), proteinuria (P = 0·009) and albuminuria (P < 0·001) but not with other SCD complications. Compared to APOL1 G1/wild type (WT), the APOL1 G2/WT genotype was associated with a lower eGFR (P = 0·04) in an age-dependent manner, suggesting that the G2/WT patients are likely to have worse kidney prognosis. Other genes variants analysed were not associated with SCN or other SCD complications. Our data indicate that APOL1 screening should be considered for the management of SCD patients, including those of non-African-American origin, as those with homozygous or double heterozygous variants are clearly at higher risk of SCN.
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Affiliation(s)
- Raphaël Kormann
- Physiology Department, Georges Pompidou European Hospital, Assistance Publique-Hôpitaux de Paris, Paris, France.,Paris Descartes Faculty of Medicine, Paris, France
| | - Anne-Sophie Jannot
- Paris Descartes Faculty of Medicine, Paris, France.,INSERM UMR 1138-E22: Information Sciences & Personalized Medicine, Paris, France.,Medical Informatics, Biostatistics and Public Health Department, Georges Pompidou University Hospital, Paris, France
| | - Céline Narjoz
- Paris Descartes Faculty of Medicine, Paris, France.,Biochemistry Department, Georges Pompidou European Hospital, Assistance Publique-Hôpitaux de Paris, Paris, France.,Institut National pour la Santé et la Recherche Médicale (INSERM) UMR-S 1147, Paris, France
| | - Jean-Antoine Ribeil
- Paris Descartes Faculty of Medicine, Paris, France.,Biotherapy Department, Necker Children's Hospital, Assistance Publique-Hôpitaux de Paris, Paris, France.,Biotherapy Clinical Investigation Centre, Groupe Hospitalier Universitaire Ouest, Assistance Publique-Hôpitaux de Paris, INSERM, Paris, France.,Centre de Référence des Syndromes Drépanocytaires Majeurs, Necker-Enfants-Malades University Hospital, APHP, Université Paris 5, Paris, France
| | - Sandra Manceau
- Paris Descartes Faculty of Medicine, Paris, France.,Biotherapy Department, Necker Children's Hospital, Assistance Publique-Hôpitaux de Paris, Paris, France
| | - Marianne Delville
- Paris Descartes Faculty of Medicine, Paris, France.,Biotherapy Department, Necker Children's Hospital, Assistance Publique-Hôpitaux de Paris, Paris, France.,Centre de Référence des Syndromes Drépanocytaires Majeurs, Necker-Enfants-Malades University Hospital, APHP, Université Paris 5, Paris, France
| | - Valentin Joste
- Paris Descartes Faculty of Medicine, Paris, France.,Biochemistry Department, Georges Pompidou European Hospital, Assistance Publique-Hôpitaux de Paris, Paris, France
| | - Dominique Prié
- Paris Descartes Faculty of Medicine, Paris, France.,INSERM U1151-CNRS UMR8253, Paris, France.,AP-HP, Necker Children's Hospital, Physiology Department, Paris Descartes University, Paris, France
| | - Jacques Pouchot
- Paris Descartes Faculty of Medicine, Paris, France.,Internal Medicine Department, Sickle Cell Referral Centre, Faculté de Médecine Paris Descartes, Sorbonne Paris-Cité et Assistance Publique-Hôpitaux de Paris, Georges Pompidou University Hospital, Paris, France
| | - Eric Thervet
- Paris Descartes Faculty of Medicine, Paris, France.,Institut National pour la Santé et la Recherche Médicale (INSERM) UMR-S 1147, Paris, France.,Department of Nephrology, Georges Pompidou University Hospital, Assistance Publique- Hôpitaux de Paris, Paris, France
| | - Marie Courbebaisse
- Physiology Department, Georges Pompidou European Hospital, Assistance Publique-Hôpitaux de Paris, Paris, France.,Paris Descartes Faculty of Medicine, Paris, France.,INSERM U1151-CNRS UMR8253, Paris, France
| | - Jean-Benoît Arlet
- Paris Descartes Faculty of Medicine, Paris, France.,Internal Medicine Department, Sickle Cell Referral Centre, Faculté de Médecine Paris Descartes, Sorbonne Paris-Cité et Assistance Publique-Hôpitaux de Paris, Georges Pompidou University Hospital, Paris, France.,Laboratory of Excellence GR-Ex, Paris, France
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Abstract
Podocytes, the postmitotic and highly branched epithelial cells of the glomerulus, play a pivotal role for the function of the glomerular filtration barrier and the development of chronic kidney disease. It has long been discussed whether podocytes in vivo are motile and can laterally migrate in a coordinated way along the capillaries until they reach the position of naked glomerular basement membrane often found in podocytopathies. Such motility would also be the prerequisite for the replacement of lost podocytes by progenitor cells. Additionally, the change of the podocyte foot processes from a normal to an effaced morphology, like it is found in many kidney diseases, would require a dynamic behavior of podocytes. Since the actin cytoskeleton is expressed in podocytes in vitro and in vivo and the morphology of podocytes is highly dependent on actin, actin-associated, and actin-regulating proteins, it was assumed that podocytes are dynamic and motile. After earlier technical limitations had been overcome and novel microscopic techniques like multiphoton microscopy had been developed, it became possible to continuously study the behavior of podocytes in living rodents and zebrafish larvae under physiological and pathological conditions. Recent in vivo microscopic studies in different model organisms suggest that lateral migration of podocytes in situ is a very unlikely event and only dynamic apical cell protrusions can be observed under pathological conditions. This review discusses recent findings concerning different forms of motility (like lateral translocative (LTM), apical translocative (ATM), and stationary motility (SM)) and their role for podocytopathies.
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Affiliation(s)
- Nicole Endlich
- Department of Anatomy and Cell Biology, University Medicine Greifswald, 17487, Greifswald, Germany. .,Institut für Anatomie und Zellbiologie, Universitätsmedizin Greifswald, Friedrich-Loeffler-Str. 23c, 17487, Greifswald, Germany.
| | - Florian Siegerist
- Department of Anatomy and Cell Biology, University Medicine Greifswald, 17487, Greifswald, Germany
| | - Karlhans Endlich
- Department of Anatomy and Cell Biology, University Medicine Greifswald, 17487, Greifswald, Germany
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35
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Siegerist F, Zhou W, Endlich K, Endlich N. 4D in vivo imaging of glomerular barrier function in a zebrafish podocyte injury model. Acta Physiol (Oxf) 2017; 220:167-173. [PMID: 27414464 DOI: 10.1111/apha.12754] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Revised: 06/27/2016] [Accepted: 07/10/2016] [Indexed: 01/15/2023]
Abstract
AIM Zebrafish larvae with their simplified pronephros are an ideal model to study glomerular physiology. Although several groups use zebrafish larvae to assess glomerular barrier function, temporary or slight changes are still difficult to measure. The aim of this study was to investigate the potential of in vivo two-photon microscopy (2-PM) for long-term imaging of glomerular barrier function in zebrafish larvae. METHODS As a proof of principle, we adapted the nitroreductase/metronidazole model of targeted podocyte ablation for 2-PM. Combination with a strain, which expresses eGFP-vitamin D-binding protein in the blood plasma, led to a strain that allowed induction of podocyte injury with parallel assessment of glomerular barrier function. We used four-dimensional (4D) 2-PM to assess eGFP fluorescence over 26 h in the vasculature and in tubules of multiple zebrafish larvae (5 days post-fertilization) simultaneously. RESULTS By 4D 2-PM, we observed that, under physiological conditions, eGFP fluorescence was retained in the vasculature and rarely detected in proximal tubule cells. Application of metronidazole induced podocyte injury and cell death as shown by TUNEL staining. Induction of podocyte injury resulted in a dramatic decrease of eGFP fluorescence in the vasculature over time (about 50% and 90% after 2 and 12 h respectively). Loss of vascular eGFP fluorescence was paralleled by an endocytosis-mediated accumulation of eGFP fluorescence in proximal tubule cells, indicating proteinuria. CONCLUSION We established a microscopy-based method to monitor the dynamics of glomerular barrier function during induction of podocyte injury in multiple zebrafish larvae simultaneously over 26 h.
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Affiliation(s)
- F. Siegerist
- Department of Anatomy and Cell Biology; University Medicine Greifswald; Greifswald Germany
| | - W. Zhou
- Department of Pediatrics and Communicable Diseases; University of Michigan; Ann Arbor MI USA
| | - K. Endlich
- Department of Anatomy and Cell Biology; University Medicine Greifswald; Greifswald Germany
| | - N. Endlich
- Department of Anatomy and Cell Biology; University Medicine Greifswald; Greifswald Germany
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Assady S, Wanner N, Skorecki KL, Huber TB. New Insights into Podocyte Biology in Glomerular Health and Disease. J Am Soc Nephrol 2017; 28:1707-1715. [PMID: 28404664 DOI: 10.1681/asn.2017010027] [Citation(s) in RCA: 66] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Podocyte and glomerular research is center stage for the development of improved preventive and therapeutic strategies for chronic progressive kidney diseases. Held April 3-6, 2016, the 11th International Podocyte Conference took place in Haifa and Jerusalem, Israel, where participants from all over the world presented their work on new developments in podocyte research. In this review, we briefly highlight the advances made in characterizing the mechanisms involved in podocyte development, metabolism, acquired injury, and repair, including progress in determining the roles of genetic variants and microRNA in particular, as well as the advances made in diagnostic techniques and therapeutics.
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Affiliation(s)
- Suheir Assady
- Department of Nephrology and Hypertension, Rambam Health Care Campus, Haifa, Israel.,Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa, Israel
| | - Nicola Wanner
- Department of Medicine IV, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Karl L Skorecki
- Department of Nephrology and Hypertension, Rambam Health Care Campus, Haifa, Israel; .,Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa, Israel
| | - Tobias B Huber
- Department of Medicine IV, Faculty of Medicine, University of Freiburg, Freiburg, Germany; .,BIOSS-Centre for Biological Signalling Studies and.,III. Medizinische Klinik, Universitätsklinikum Hamburg-Eppendorf, Hamburg, Germany.,ZBSA-Center for Biological Systems Analysis, Albert Ludwigs University, Freiburg, Germany; and
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Schenk H, Müller-Deile J, Kinast M, Schiffer M. Disease modeling in genetic kidney diseases: zebrafish. Cell Tissue Res 2017; 369:127-141. [PMID: 28331970 DOI: 10.1007/s00441-017-2593-0] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Accepted: 02/22/2017] [Indexed: 01/07/2023]
Abstract
Growing numbers of translational genomics studies are based on the highly efficient and versatile zebrafish (Danio rerio) vertebrate model. The increasing types of zebrafish models have improved our understanding of inherited kidney diseases, since they not only display pathophysiological changes but also give us the opportunity to develop and test novel treatment options in a high-throughput manner. New paradigms in inherited kidney diseases have been developed on the basis of the distinct genome conservation of approximately 70 % between zebrafish and humans in terms of existing gene orthologs. Several options are available to determine the functional role of a specific gene or gene sets. Permanent genome editing can be induced via complete gene knockout by using the CRISPR/Cas-system, among others, or via transient modification by using various morpholino techniques. Cross-species rescues succeeding knockdown techniques are employed to determine the functional significance of a target gene or a specific mutation. This article summarizes the current techniques and discusses their perspectives.
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Affiliation(s)
- Heiko Schenk
- Department of Medicine/Nephrology, Hannover Medical School, Hannover, Germany
- Mount Desert Island Biological Laboratory, Salisbury Cove, Bar Harbor, Me., USA
| | - Janina Müller-Deile
- Department of Medicine/Nephrology, Hannover Medical School, Hannover, Germany
- Mount Desert Island Biological Laboratory, Salisbury Cove, Bar Harbor, Me., USA
| | - Mark Kinast
- Department of Medicine/Nephrology, Hannover Medical School, Hannover, Germany
- Mount Desert Island Biological Laboratory, Salisbury Cove, Bar Harbor, Me., USA
| | - Mario Schiffer
- Department of Medicine/Nephrology, Hannover Medical School, Hannover, Germany.
- Mount Desert Island Biological Laboratory, Salisbury Cove, Bar Harbor, Me., USA.
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Thomasova D, Ebrahim M, Fleckinger K, Li M, Molnar J, Popper B, Liapis H, Kotb AM, Siegerist F, Endlich N, Anders HJ. MDM2 prevents spontaneous tubular epithelial cell death and acute kidney injury. Cell Death Dis 2016; 7:e2482. [PMID: 27882940 PMCID: PMC5260907 DOI: 10.1038/cddis.2016.390] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2016] [Revised: 10/21/2016] [Accepted: 10/25/2016] [Indexed: 12/24/2022]
Abstract
Murine double minute-2 (MDM2) is an E3-ubiquitin ligase and the main negative regulator of tumor suppressor gene p53. MDM2 has also a non-redundant function as a modulator of NF-kB signaling. As such it promotes proliferation and inflammation. MDM2 is highly expressed in the unchallenged tubular epithelial cells and we hypothesized that MDM2 is necessary for their survival and homeostasis. MDM2 knockdown by siRNA or by genetic depletion resulted in demise of tubular cells in vitro. This phenotype was completely rescued by concomitant knockdown of p53, thus suggesting p53 dependency. In vivo experiments in the zebrafish model demonstrated that the tubulus cells of the larvae undergo cell death after the knockdown of mdm2. Doxycycline-induced deletion of MDM2 in tubular cell-specific MDM2-knockout mice Pax8rtTa-cre; MDM2f/f caused acute kidney injury with increased plasma creatinine and blood urea nitrogen and sharp decline of glomerular filtration rate. Histological analysis showed massive swelling of renal tubular cells and later their loss and extensive tubular dilation, markedly in proximal tubules. Ultrastructural changes of tubular epithelial cells included swelling of the cytoplasm and mitochondria with the loss of cristae and their transformation in the vacuoles. The pathological phenotype of the tubular cell-specific MDM2-knockout mouse model was completely rescued by co-deletion of p53. Tubular epithelium compensates only partially for the cell loss caused by MDM2 depletion by proliferation of surviving tubular cells, with incomplete MDM2 deletion, but rather mesenchymal healing occurs. We conclude that MDM2 is a non-redundant survival factor for proximal tubular cells by protecting them from spontaneous p53 overexpression-related cell death.
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Affiliation(s)
- Dana Thomasova
- Nephrologisches Zentrum, Medizinische Klinik und Poliklinik IV, Klinikum der LMU München, Munich, Germany
| | - Martrez Ebrahim
- Nephrologisches Zentrum, Medizinische Klinik und Poliklinik IV, Klinikum der LMU München, Munich, Germany
| | - Kristina Fleckinger
- Nephrologisches Zentrum, Medizinische Klinik und Poliklinik IV, Klinikum der LMU München, Munich, Germany
| | - Moying Li
- Nephrologisches Zentrum, Medizinische Klinik und Poliklinik IV, Klinikum der LMU München, Munich, Germany
| | - Jakob Molnar
- Nephrologisches Zentrum, Medizinische Klinik und Poliklinik IV, Klinikum der LMU München, Munich, Germany
| | - Bastian Popper
- Department of Anatomy and Cell Biology, Ludwig-Maximilians Universität, Munich, Germany
| | - Helen Liapis
- Pathology & Immunology & Internal Medicine (Renal), Washington University, School of Medicine, St Louis, MO, USA
| | - Ahmed M Kotb
- Department of Anatomy and Cell Biology, Universitätsmedizin Greifswald, Greifswald, Germany
- Department of Anatomy and Histology, Faculty of Veterinary Medicine, Assiut University, Assiut, Egypt
| | - Florian Siegerist
- Department of Anatomy and Cell Biology, Universitätsmedizin Greifswald, Greifswald, Germany
| | - Nicole Endlich
- Department of Anatomy and Cell Biology, Universitätsmedizin Greifswald, Greifswald, Germany
| | - Hans-Joachim Anders
- Nephrologisches Zentrum, Medizinische Klinik und Poliklinik IV, Klinikum der LMU München, Munich, Germany
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Pitchers WR, Constantinou SJ, Losilla M, Gallant JR. Electric fish genomics: Progress, prospects, and new tools for neuroethology. ACTA ACUST UNITED AC 2016; 110:259-272. [PMID: 27769923 DOI: 10.1016/j.jphysparis.2016.10.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Revised: 09/06/2016] [Accepted: 10/16/2016] [Indexed: 01/01/2023]
Abstract
Electric fish have served as a model system in biology since the 18th century, providing deep insight into the nature of bioelectrogenesis, the molecular structure of the synapse, and brain circuitry underlying complex behavior. Neuroethologists have collected extensive phenotypic data that span biological levels of analysis from molecules to ecosystems. This phenotypic data, together with genomic resources obtained over the past decades, have motivated new and exciting hypotheses that position the weakly electric fish model to address fundamental 21st century biological questions. This review article considers the molecular data collected for weakly electric fish over the past three decades, and the insights that data of this nature has motivated. For readers relatively new to molecular genetics techniques, we also provide a table of terminology aimed at clarifying the numerous acronyms and techniques that accompany this field. Next, we pose a research agenda for expanding genomic resources for electric fish research over the next 10years. We conclude by considering some of the exciting research prospects for neuroethology that electric fish genomics may offer over the coming decades, if the electric fish community is successful in these endeavors.
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Affiliation(s)
- William R Pitchers
- Dept. of Integrative Biology, Michigan State University, 288 Farm Lane RM 203, East Lansing, MI 48824, USA.
| | - Savvas J Constantinou
- Dept. of Integrative Biology, Michigan State University, 288 Farm Lane RM 203, East Lansing, MI 48824, USA
| | - Mauricio Losilla
- Dept. of Integrative Biology, Michigan State University, 288 Farm Lane RM 203, East Lansing, MI 48824, USA
| | - Jason R Gallant
- Dept. of Integrative Biology, Michigan State University, 288 Farm Lane RM 203, East Lansing, MI 48824, USA.
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