1
|
Liu PJ, Sayeeda K, Zhuang C, Krendel M. Roles of myosin 1e and the actin cytoskeleton in kidney functions and familial kidney disease. Cytoskeleton (Hoboken) 2024. [PMID: 38708443 DOI: 10.1002/cm.21861] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2023] [Revised: 03/21/2024] [Accepted: 04/04/2024] [Indexed: 05/07/2024]
Abstract
Mammalian kidneys are responsible for removing metabolic waste and maintaining fluid and electrolyte homeostasis via selective filtration. One of the proteins closely linked to selective renal filtration is myosin 1e (Myo1e), an actin-dependent molecular motor found in the specialized kidney epithelial cells involved in the assembly and maintenance of the renal filter. Point mutations in the gene encoding Myo1e, MYO1E, have been linked to familial kidney disease, and Myo1e knockout in mice leads to the disruption of selective filtration. In this review, we discuss the role of the actin cytoskeleton in renal filtration, the known and hypothesized functions of Myo1e, and the possible explanations for the impact of MYO1E mutations on renal function.
Collapse
Affiliation(s)
- Pei-Ju Liu
- Department of Cell and Developmental Biology, State University of New York Upstate Medical University, Syracuse, New York, USA
| | - Kazi Sayeeda
- Department of Cell and Developmental Biology, State University of New York Upstate Medical University, Syracuse, New York, USA
| | - Cindy Zhuang
- Department of Cell and Developmental Biology, State University of New York Upstate Medical University, Syracuse, New York, USA
| | - Mira Krendel
- Department of Cell and Developmental Biology, State University of New York Upstate Medical University, Syracuse, New York, USA
| |
Collapse
|
2
|
Wang T, Chen S, Wang Z, Li S, Fei X, Wang T, Zhang M. KIRREL promotes the proliferation of gastric cancer cells and angiogenesis through the PI3K/AKT/mTOR pathway. J Cell Mol Med 2024; 28:e18020. [PMID: 37909722 PMCID: PMC10805501 DOI: 10.1111/jcmm.18020] [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: 05/23/2023] [Revised: 10/14/2023] [Accepted: 10/19/2023] [Indexed: 11/03/2023] Open
Abstract
Anti-angiogenesis is a promising therapeutic strategy for delaying tumour progression that offers, new hope for gastric cancer targeted therapy. The purpose of this study was to investigate the precise mechanism by which Kin of IRRE-like protein 1 (KIRREL) contributes to the development of gastric cancer, particularly in terms of tumour angiogenesis. Differential expression of KIRREL in tissues and cells was detected using quantitative real-time polymerase chain reaction, western blotting and immunohistochemistry. A bioinformatics analysis was conducted to screen for the function and pathway enrichment of KIRREL in gastric cancer. Lentivirus-induced KIRREL silencing in SNU-5 cells and lentivirus-induced KIRREL overexpression in AGS cells were used to study the effect of KIRREL on the proliferation, cell cycle and angiogenesis of gastric cancer cells. Moreover, the expressions of PI3K, P-PI3K, AKT, P-AKT, mTOR, P-mTOR, HIF-1α and VEGF were also detected. Gastric cancer tissues and cells had high levels of KIRREL expression, which is associated with the proliferation, cell cycle and angiogenesis of gastric cancer cells. After silencing and overexpressing KIRREL in SNU-5 and AGS cells, respectively, the proliferation and angiogenesis of SNU-5 cells were inhibited, while the proliferation and angiogenesis of AGS cells were promoted. According to a bioinformatics analysis of the KIRREL gene, angiogenesis regulation and the PI3K/AKT pathway were highly connected. The PI3K/AKT/mTOR pathway was repressed and stimulated by KIRREL silencing and overexpression, respectively. IGF-1, an AKT agonist, and LY294002, an inhibitor, reversed the effects of KIRREL silencing and overexpression on the PI3K/AKT/mTOR pathway and on gastric cancer cell proliferation and angiogenesis. KIRREL may mediate the proliferation and angiogenesis of gastric cancer cells through the PI3K/AKT/mTOR signalling pathway. These findings could help in the further development of potential anti-angiogenesis targets.
Collapse
Affiliation(s)
- Tao Wang
- Department of OncologyThe Second Affiliated Hospital of Anhui Medical UniversityHefeiAnhuiChina
| | - Shuo Chen
- Department of OncologyThe Second Affiliated Hospital of Anhui Medical UniversityHefeiAnhuiChina
| | - Ziliang Wang
- Department of OncologyThe Second Affiliated Hospital of Anhui Medical UniversityHefeiAnhuiChina
| | - Siyu Li
- Department of OncologyThe Second Affiliated Hospital of Anhui Medical UniversityHefeiAnhuiChina
| | - Xichang Fei
- Department of OncologyThe Second Affiliated Hospital of Anhui Medical UniversityHefeiAnhuiChina
| | - Tong Wang
- Department of General PracticeThe Second Affiliated Hospital of Anhui Medical UniversityHefeiAnhuiChina
| | - Mingjun Zhang
- Department of OncologyThe Second Affiliated Hospital of Anhui Medical UniversityHefeiAnhuiChina
| |
Collapse
|
3
|
Gerlach GF, Imseis ZH, Cooper SL, Santos AN, O’Brien LL. Mapping of the podocin proximity-dependent proteome reveals novel components of the kidney podocyte foot process. Front Cell Dev Biol 2023; 11:1195037. [PMID: 37325559 PMCID: PMC10262054 DOI: 10.3389/fcell.2023.1195037] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Accepted: 05/03/2023] [Indexed: 06/17/2023] Open
Abstract
Introduction: The unique architecture of glomerular podocytes is integral to kidney filtration. Interdigitating foot processes extend from the podocyte cell body, wrap around fenestrated capillaries, and form specialized junctional complexes termed slit diaphragms to create a molecular sieve. However, the full complement of proteins which maintain foot process integrity, and how this localized proteome changes with disease, remain to be elucidated. Methods: Proximity-dependent biotin identification (BioID) enables the identification of spatially localized proteomes. To this end, we developed a novel in vivo BioID knock-in mouse model. We utilized the slit diaphragm protein podocin (Nphs2) to create a podocin-BioID fusion. Podocin-BioID localizes to the slit diaphragm, and biotin injection leads to podocyte-specific protein biotinylation. We isolated the biotinylated proteins and performed mass spectrometry to identify proximal interactors. Results and Discussion: Gene ontology analysis of 54 proteins specifically enriched in our podocin-BioID sample revealed 'cell junctions,' 'actin binding,' and 'cytoskeleton organization' as top terms. Known foot process components were identified, and we further uncovered two novel proteins: the tricellular junctional protein Ildr2 and the CDC42 and N-WASP interactor Fnbp1l. We confirmed that Ildr2 and Fnbp1l are expressed by podocytes and partially colocalize with podocin. Finally, we investigated how this proteome changes with age and uncovered a significant increase in Ildr2. This was confirmed by immunofluorescence on human kidney samples and suggests altered junctional composition may preserve podocyte integrity. Together, these assays have led to new insights into podocyte biology and support the efficacy of utilizing BioID in vivo to interrogate spatially localized proteomes in health, aging, and disease.
Collapse
Affiliation(s)
| | | | | | | | - Lori L. O’Brien
- Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| |
Collapse
|
4
|
Seifert L, Zahner G, Meyer-Schwesinger C, Hickstein N, Dehde S, Wulf S, Köllner SMS, Lucas R, Kylies D, Froembling S, Zielinski S, Kretz O, Borodovsky A, Biniaminov S, Wang Y, Cheng H, Koch-Nolte F, Zipfel PF, Hopfer H, Puelles VG, Panzer U, Huber TB, Wiech T, Tomas NM. The classical pathway triggers pathogenic complement activation in membranous nephropathy. Nat Commun 2023; 14:473. [PMID: 36709213 PMCID: PMC9884226 DOI: 10.1038/s41467-023-36068-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Accepted: 01/13/2023] [Indexed: 01/29/2023] Open
Abstract
Membranous nephropathy (MN) is an antibody-mediated autoimmune disease characterized by glomerular immune complexes containing complement components. However, both the initiation pathways and the pathogenic significance of complement activation in MN are poorly understood. Here, we show that components from all three complement pathways (alternative, classical and lectin) are found in renal biopsies from patients with MN. Proximity ligation assays to directly visualize complement assembly in the tissue reveal dominant activation via the classical pathway, with a close correlation to the degree of glomerular C1q-binding IgG subclasses. In an antigen-specific autoimmune mouse model of MN, glomerular damage and proteinuria are reduced in complement-deficient mice compared with wild-type littermates. Severe disease with progressive ascites, accompanied by extensive loss of the integral podocyte slit diaphragm proteins, nephrin and neph1, only occur in wild-type animals. Finally, targeted silencing of C3 using RNA interference after the onset of proteinuria significantly attenuates disease. Our study shows that, in MN, complement is primarily activated via the classical pathway and targeting complement components such as C3 may represent a promising therapeutic strategy.
Collapse
Affiliation(s)
- Larissa Seifert
- III. Department of Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.,Hamburg Center for Kidney Health (HCKH), University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Gunther Zahner
- III. Department of Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.,Hamburg Center for Kidney Health (HCKH), University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Catherine Meyer-Schwesinger
- Hamburg Center for Kidney Health (HCKH), University Medical Center Hamburg-Eppendorf, Hamburg, Germany.,Institute of Cellular and Integrative Physiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Naemi Hickstein
- III. Department of Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.,Hamburg Center for Kidney Health (HCKH), University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Silke Dehde
- III. Department of Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.,Hamburg Center for Kidney Health (HCKH), University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Sonia Wulf
- Institute of Pathology, Nephropathology Section, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Sarah M S Köllner
- III. Department of Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.,Hamburg Center for Kidney Health (HCKH), University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Renke Lucas
- III. Department of Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.,Hamburg Center for Kidney Health (HCKH), University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Dominik Kylies
- III. Department of Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.,Hamburg Center for Kidney Health (HCKH), University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Sarah Froembling
- Hamburg Center for Kidney Health (HCKH), University Medical Center Hamburg-Eppendorf, Hamburg, Germany.,Institute of Cellular and Integrative Physiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Stephanie Zielinski
- Hamburg Center for Kidney Health (HCKH), University Medical Center Hamburg-Eppendorf, Hamburg, Germany.,Institute of Cellular and Integrative Physiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Oliver Kretz
- III. Department of Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.,Hamburg Center for Kidney Health (HCKH), University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | | | | | - Yanyan Wang
- Division of Nephrology, Beijing Anzhen Hospital, Capital Medical University, Beijing, China
| | - Hong Cheng
- Division of Nephrology, Beijing Anzhen Hospital, Capital Medical University, Beijing, China
| | - Friedrich Koch-Nolte
- Institute of Immunology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Peter F Zipfel
- Department of Infection Biology, Leibniz Institute for Natural Product Research and Infection Biology, Hans Knöll Institute, Jena, Germany.,Institute of Microbiology, Friedrich Schiller University, Jena, Germany
| | - Helmut Hopfer
- Department of Medical Genetics and Pathology, University Hospital Basel, University of Basel, Basel, Switzerland
| | - Victor G Puelles
- III. Department of Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.,Hamburg Center for Kidney Health (HCKH), University Medical Center Hamburg-Eppendorf, Hamburg, Germany.,Department of Clinical Medicine, Aarhus University, Aarhus, Denmark.,Department of Pathology, Aarhus University Hospital, Aarhus, Denmark
| | - Ulf Panzer
- III. Department of Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.,Hamburg Center for Kidney Health (HCKH), University Medical Center Hamburg-Eppendorf, Hamburg, Germany.,Hamburg Center for Translational Immunology (HCTI), University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Tobias B Huber
- III. Department of Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.,Hamburg Center for Kidney Health (HCKH), University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Thorsten Wiech
- Hamburg Center for Kidney Health (HCKH), University Medical Center Hamburg-Eppendorf, Hamburg, Germany.,Institute of Pathology, Nephropathology Section, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Nicola M Tomas
- III. Department of Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany. .,Hamburg Center for Kidney Health (HCKH), University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
| |
Collapse
|
5
|
Lee Y, Wang M, Imamura K, Sato M. Quantitative analysis of the roles of IRM cell adhesion molecules in column formation in the fly brain. Dev Growth Differ 2023; 65:37-47. [PMID: 36534021 DOI: 10.1111/dgd.12834] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Revised: 11/20/2022] [Accepted: 11/25/2022] [Indexed: 12/23/2022]
Abstract
The Drosophila visual center shows columnar structures, basic structural and functional units of the brain, that are shared with the mammalian cerebral cortex. Visual information received in the ommatidia in the compound eye is transmitted to the columns in the brain. However, the developmental mechanisms of column formation are largely unknown. The Irre Cell Recognition Module (IRM) proteins are a family of immunoglobulin cell adhesion molecules. The four Drosophila IRM proteins are localized to the developing columns, the structure of which is affected in IRM mutants, suggesting that IRM proteins are essential for column formation. Since IRM proteins are cell adhesion molecules, they may regulate cell adhesion between columnar neurons. To test this possibility, we specifically knocked down IRM genes in columnar neurons and examined the defects in column formation. We developed a system that automatically extracts the individual column images and quantifies the column shape. Using this system, we demonstrated that IRM genes play critical roles in regulating column shape in a core columnar neuron, Mi1. We also show that their expression in the other columnar neurons, Mi4 and T4/5, is essential, suggesting that the interactions between IRM proteins and multiple neurons shape the columns in the fly brain.
Collapse
Affiliation(s)
- Yunfei Lee
- Graduate School of Medical Sciences, Kanazawa University, Kanazawa, Japan
| | - Miaoxing Wang
- Mathematical Neuroscience Unit, Institute for Frontier Science Initiative, Kanazawa, Japan
| | - Kousuke Imamura
- Faculty of Electrical, Information and Communication Engineering, Institute of Science and Engineering, Kanazawa University, Kanazawa, Japan
| | - Makoto Sato
- Graduate School of Medical Sciences, Kanazawa University, Kanazawa, Japan.,Mathematical Neuroscience Unit, Institute for Frontier Science Initiative, Kanazawa, Japan
| |
Collapse
|
6
|
A slit-diaphragm-associated protein network for dynamic control of renal filtration. Nat Commun 2022; 13:6446. [PMID: 36307401 PMCID: PMC9616960 DOI: 10.1038/s41467-022-33748-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Accepted: 09/29/2022] [Indexed: 12/25/2022] Open
Abstract
The filtration of blood in the kidney which is crucial for mammalian life is determined by the slit-diaphragm, a cell-cell junction between the foot processes of renal podocytes. The slit-diaphragm is thought to operate as final barrier or as molecular sensor of renal filtration. Using high-resolution proteomic analysis of slit-diaphragms affinity-isolated from rodent kidney, we show that the native slit-diaphragm is built from the junction-forming components Nephrin, Neph1 and Podocin and a co-assembled high-molecular weight network of proteins. The network constituents cover distinct classes of proteins including signaling-receptors, kinases/phosphatases, transporters and scaffolds. Knockout or knock-down of either the core components or the selected network constituents tyrosine kinase MER (MERTK), atrial natriuretic peptide-receptor C (ANPRC), integral membrane protein 2B (ITM2B), membrane-associated guanylate-kinase, WW and PDZ-domain-containing protein1 (MAGI1) and amyloid protein A4 resulted in target-specific impairment or disruption of the filtration process. Our results identify the slit-diaphragm as a multi-component system that is endowed with context-dependent dynamics via a co-assembled protein network.
Collapse
|
7
|
Gu Y, Wang Y, Sha Z, He C, Zhu Y, Li J, Yu A, Zhong Z, Wang X, Sun Y, Lan F, Yu FX. Transmembrane protein KIRREL1 regulates Hippo signaling via a feedback loop and represents a therapeutic target in YAP/TAZ-active cancers. Cell Rep 2022; 40:111296. [PMID: 36044856 DOI: 10.1016/j.celrep.2022.111296] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2022] [Revised: 07/05/2022] [Accepted: 08/10/2022] [Indexed: 11/18/2022] Open
Abstract
The Hippo tumor-suppressor pathway is frequently dysregulated in human cancers and represents a therapeutic target. However, strategies targeting the mammalian Hippo pathway are limited because of the lack of a well-established cell-surface regulator. Here, we show that transmembrane protein KIRREL1, by interacting with both SAV1 and LATS1/2, promotes LATS1/2 activation by MST1/2 (Hippo kinases), and LATS1/2 activation, in turn, inhibits activity of YAP/TAZ oncoproteins. Conversely, YAP/TAZ directly induce the expression of KIRREL1 in a TEAD1-4-dependent manner. Indeed, KIRREL1 expression positively correlates with canonical YAP/TAZ target gene expression in clinical tumor specimens and predicts poor prognosis. Moreover, transgenic expression of KIRREL1 effectively blocks tumorigenesis in a mouse intrahepatic cholangiocarcinoma model, indicating a tumor-suppressor role of KIRREL1. Hence, KIRREL1 constitutes a negative feedback mechanism regulating the Hippo pathway and serves as a cell-surface marker and potential drug target in cancers with YAP/TAZ dependency.
Collapse
Affiliation(s)
- Yuan Gu
- Institute of Pediatrics, Children's Hospital of Fudan University, and the Shanghai Key Laboratory of Medical Epigenetics, The International Co-laboratory of Medical Epigenetics and Metabolism, the State Key Laboratory of Genetic Engineering, Institutes of Biomedical Sciences, Shanghai Medical College, Fudan University, Shanghai 200032, China; Department of General Surgery, Zhongshan Hospital, Fudan University, Shanghai 200032 China
| | - Yu Wang
- Institute of Pediatrics, Children's Hospital of Fudan University, and the Shanghai Key Laboratory of Medical Epigenetics, The International Co-laboratory of Medical Epigenetics and Metabolism, the State Key Laboratory of Genetic Engineering, Institutes of Biomedical Sciences, Shanghai Medical College, Fudan University, Shanghai 200032, China
| | - Zhao Sha
- Institute of Pediatrics, Children's Hospital of Fudan University, and the Shanghai Key Laboratory of Medical Epigenetics, The International Co-laboratory of Medical Epigenetics and Metabolism, the State Key Laboratory of Genetic Engineering, Institutes of Biomedical Sciences, Shanghai Medical College, Fudan University, Shanghai 200032, China
| | - Chenxi He
- Shanghai Key Laboratory of Medical Epigenetics, International Laboratory of Medical Epigenetics and Metabolism, Ministry of Science and Technology, Institutes of Biomedical Sciences, Fudan University, and Key Laboratory of Carcinogenesis and Cancer Invasion, Ministry of Education, Liver Cancer Institute, Zhongshan Hospital, Fudan University, Shanghai 200032, China
| | - Yuwen Zhu
- Institute of Pediatrics, Children's Hospital of Fudan University, and the Shanghai Key Laboratory of Medical Epigenetics, The International Co-laboratory of Medical Epigenetics and Metabolism, the State Key Laboratory of Genetic Engineering, Institutes of Biomedical Sciences, Shanghai Medical College, Fudan University, Shanghai 200032, China
| | - Jian Li
- Institute of Pediatrics, Children's Hospital of Fudan University, and the Shanghai Key Laboratory of Medical Epigenetics, The International Co-laboratory of Medical Epigenetics and Metabolism, the State Key Laboratory of Genetic Engineering, Institutes of Biomedical Sciences, Shanghai Medical College, Fudan University, Shanghai 200032, China
| | - Aijuan Yu
- Institute of Pediatrics, Children's Hospital of Fudan University, and the Shanghai Key Laboratory of Medical Epigenetics, The International Co-laboratory of Medical Epigenetics and Metabolism, the State Key Laboratory of Genetic Engineering, Institutes of Biomedical Sciences, Shanghai Medical College, Fudan University, Shanghai 200032, China
| | - Zhenxing Zhong
- Institute of Pediatrics, Children's Hospital of Fudan University, and the Shanghai Key Laboratory of Medical Epigenetics, The International Co-laboratory of Medical Epigenetics and Metabolism, the State Key Laboratory of Genetic Engineering, Institutes of Biomedical Sciences, Shanghai Medical College, Fudan University, Shanghai 200032, China
| | - Xuefei Wang
- Department of General Surgery, Zhongshan Hospital, Fudan University, Shanghai 200032 China
| | - Yihong Sun
- Department of General Surgery, Zhongshan Hospital, Fudan University, Shanghai 200032 China
| | - Fei Lan
- Shanghai Key Laboratory of Medical Epigenetics, International Laboratory of Medical Epigenetics and Metabolism, Ministry of Science and Technology, Institutes of Biomedical Sciences, Fudan University, and Key Laboratory of Carcinogenesis and Cancer Invasion, Ministry of Education, Liver Cancer Institute, Zhongshan Hospital, Fudan University, Shanghai 200032, China
| | - Fa-Xing Yu
- Institute of Pediatrics, Children's Hospital of Fudan University, and the Shanghai Key Laboratory of Medical Epigenetics, The International Co-laboratory of Medical Epigenetics and Metabolism, the State Key Laboratory of Genetic Engineering, Institutes of Biomedical Sciences, Shanghai Medical College, Fudan University, Shanghai 200032, China.
| |
Collapse
|
8
|
Lang K, Milosavljevic J, Heinkele H, Chen M, Gerstner L, Spitz D, Kayser S, Helmstädter M, Walz G, Köttgen M, Spracklen A, Poulton J, Hermle T. Selective endocytosis controls slit diaphragm maintenance and dynamics in Drosophila nephrocytes. eLife 2022; 11:79037. [PMID: 35876643 PMCID: PMC9355562 DOI: 10.7554/elife.79037] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Accepted: 07/24/2022] [Indexed: 11/28/2022] Open
Abstract
The kidneys generate about 180 l of primary urine per day by filtration of plasma. An essential part of the filtration barrier is the slit diaphragm, a multiprotein complex containing nephrin as major component. Filter dysfunction typically manifests with proteinuria and mutations in endocytosis regulating genes were discovered as causes of proteinuria. However, it is unclear how endocytosis regulates the slit diaphragm and how the filtration barrier is maintained without either protein leakage or filter clogging. Here, we study nephrin dynamics in podocyte-like nephrocytes of Drosophila and show that selective endocytosis either by dynamin- or flotillin-mediated pathways regulates a stable yet highly dynamic architecture. Short-term manipulation of endocytic functions indicates that dynamin-mediated endocytosis of ectopic nephrin restricts slit diaphragm formation spatially while flotillin-mediated turnover of nephrin within the slit diaphragm is needed to maintain filter permeability by shedding of molecules bound to nephrin in endosomes. Since slit diaphragms cannot be studied in vitro and are poorly accessible in mouse models, this is the first analysis of their dynamics within the slit diaphragm multiprotein complex. Identification of the mechanisms of slit diaphragm maintenance will help to develop novel therapies for proteinuric renal diseases that are frequently limited to symptomatic treatment.
Collapse
Affiliation(s)
- Konrad Lang
- Department of Medicine, University of Freiburg, Freiburg, Germany
| | | | - Helena Heinkele
- Department of Medicine, University of Freiburg, Freiburg, Germany
| | - Mengmeng Chen
- Department of Medicine, University of Freiburg, Freiburg, Germany
| | - Lea Gerstner
- Department of Medicine, University of Freiburg, Freiburg, Germany
| | - Dominik Spitz
- Department of Medicine, University of Freiburg, Freiburg, Germany
| | - Severine Kayser
- Department of Medicine, University of Freiburg, Freiburg, Germany
| | | | - Gerd Walz
- Department of Medicine, University of Freiburg, Freiburg, Germany
| | - Michael Köttgen
- Department of Medicine, University of Freiburg, Freiburg, Germany
| | - Andrew Spracklen
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, United States
| | - John Poulton
- Department of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, United States
| | - Tobias Hermle
- Department of Medicine, University of Freiburg, Freiburg, Germany
| |
Collapse
|
9
|
Dow JAT, Simons M, Romero MF. Drosophila melanogaster: a simple genetic model of kidney structure, function and disease. Nat Rev Nephrol 2022; 18:417-434. [PMID: 35411063 DOI: 10.1038/s41581-022-00561-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/07/2022] [Indexed: 12/27/2022]
Abstract
Although the genetic basis of many kidney diseases is being rapidly elucidated, their experimental study remains problematic owing to the lack of suitable models. The fruitfly Drosophila melanogaster provides a rapid, ethical and cost-effective model system of the kidney. The unique advantages of D. melanogaster include ease and low cost of maintenance, comprehensive availability of genetic mutants and powerful transgenic technologies, and less onerous regulation, as compared with mammalian systems. Renal and excretory functions in D. melanogaster reside in three main tissues - the transporting renal (Malpighian) tubules, the reabsorptive hindgut and the endocytic nephrocytes. Tubules contain multiple cell types and regions and generate a primary urine by transcellular transport rather than filtration, which is then subjected to selective reabsorption in the hindgut. By contrast, the nephrocytes are specialized for uptake of macromolecules and equipped with a filtering slit diaphragm resembling that of podocytes. Many genes with key roles in the human kidney have D. melanogaster orthologues that are enriched and functionally relevant in fly renal tissues. This similarity has allowed investigations of epithelial transport, kidney stone formation and podocyte and proximal tubule function. Furthermore, a range of unique quantitative phenotypes are available to measure function in both wild type and disease-modelling flies.
Collapse
Affiliation(s)
- Julian A T Dow
- Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK.
| | - Matias Simons
- INSERM UMR1163, Laboratory of Epithelial Biology and Disease, Imagine Institute, Université de Paris, Hôpital Necker-Enfants Malades, Paris, France
- Institute of Human Genetics, University Hospital Heidelberg, Heidelberg, Germany
| | - Michael F Romero
- Department of Physiology and Biomedical Engineering, Division of Nephrology and Hypertension, Mayo Clinic College of Medicine and Science, Rochester, MN, USA
| |
Collapse
|
10
|
Wang C, Feng X, Su D, Chen Z, Wang S, Tang M, Huang M, Nie L, Zhang H, Li S, Yin L, Johnson RL, Hart T, Chen J. Integrated screens uncover a cell surface tumor suppressor gene KIRREL involved in Hippo pathway. Proc Natl Acad Sci U S A 2022; 119:e2121779119. [PMID: 35704761 PMCID: PMC9231494 DOI: 10.1073/pnas.2121779119] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Accepted: 05/12/2022] [Indexed: 01/07/2023] Open
Abstract
Cell surface proteins play essential roles in various biological processes and are highly related to cancer development. They also serve as important markers for cell identity and targets for pharmacological intervention. Despite their great potentials in biomedical research, comprehensive functional analysis of cell surface proteins remains scarce. Here, with a de novo designed library targeting cell surface proteins, we performed in vivo CRISPR screens to evaluate the effects of cell surface proteins on tumor survival and proliferation. We found that Kirrel1 loss markedly promoted tumor growth in vivo. Moreover, KIRREL was significantly enriched in a separate CRISPR screen based on a specific Hippo pathway reporter. Further studies revealed that KIRREL binds directly to SAV1 to activate the Hippo tumor suppressor pathway. Together, our integrated screens reveal a cell surface tumor suppressor involved in the Hippo pathway and highlight the potential of these approaches in biomedical research.
Collapse
Affiliation(s)
- Chao Wang
- Department of Experimental Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX
| | - Xu Feng
- Department of Experimental Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX
| | - Dan Su
- Department of Experimental Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX
| | - Zhen Chen
- Department of Experimental Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX
| | - Shimin Wang
- Department of Experimental Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX
| | - Mengfan Tang
- Department of Experimental Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX
| | - Min Huang
- Department of Experimental Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX
| | - Litong Nie
- Department of Experimental Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX
| | - Huimin Zhang
- Department of Experimental Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX
| | - Siting Li
- Department of Experimental Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX
| | - Ling Yin
- Department of Experimental Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX
| | - Randy L. Johnson
- Department of Cancer Biology, The University of Texas MD Anderson Cancer Center, Houston, TX
| | - Traver Hart
- Department of Bioinformatics and Computational Biology, The University of Texas MD Anderson Cancer Center, Houston, TX
| | - Junjie Chen
- Department of Experimental Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX
| |
Collapse
|
11
|
Xiao M, Bohnert BN, Grahammer F, Artunc F. Rodent models to study sodium retention in experimental nephrotic syndrome. Acta Physiol (Oxf) 2022; 235:e13844. [PMID: 35569011 DOI: 10.1111/apha.13844] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2022] [Revised: 05/02/2022] [Accepted: 05/10/2022] [Indexed: 12/12/2022]
Abstract
Sodium retention and edema are hallmarks of nephrotic syndrome (NS). Different experimental rodent models have been established for simulating NS, however, not all of them feature sodium retention which requires proteinuria to exceed a certain threshold. In rats, puromycin aminonucleoside nephrosis (PAN) is a classic NS model introduced in 1955 that was adopted as doxorubicin-induced nephropathy (DIN) in 129S1/SvImJ mice. In recent years, mice with inducible podocin deletion (Nphs2Δipod ) or podocyte apoptosis (POD-ATTAC) have been developed. In these models, sodium retention is thought to be caused by activation of the epithelial sodium channel (ENaC) in the distal nephron through aberrantly filtered serine proteases or proteasuria. Strikingly, rodent NS models follow an identical chronological time course after the development of proteinuria featuring sodium retention within days and spontaneous reversal thereafter. In DIN and Nphs2Δipod mice, inhibition of ENaC by amiloride or urinary serine protease activity by aprotinin prevents sodium retention, opening up new and promising therapeutic approaches that could be translated into the treatment of nephrotic patients. However, the essential serine protease(s) responsible for ENaC activation is (are) still unknown. With the use of nephrotic rodent models, there is the possibility that this (these) will be identified in the future. This review summarizes the various rodent models used to study experimental nephrotic syndrome and the insights gained from these models with regard to the pathophysiology of sodium retention.
Collapse
Affiliation(s)
- Mengyun Xiao
- Division of Endocrinology, Diabetology and Nephrology, Department of Internal Medicine University Hospital Tübingen Tübingen Germany
| | - Bernhard N. Bohnert
- Division of Endocrinology, Diabetology and Nephrology, Department of Internal Medicine University Hospital Tübingen Tübingen Germany
- Institute of Diabetes Research and Metabolic Diseases (IDM) of the Helmholtz Center Munich at the University Tübingen Tübingen Germany
- German Center for Diabetes Research (DZD) at the University Tübingen Tübingen Germany
| | - Florian Grahammer
- III. Department of Medicine University Medical Center Hamburg‐Eppendorf Hamburg Germany
| | - Ferruh Artunc
- Division of Endocrinology, Diabetology and Nephrology, Department of Internal Medicine University Hospital Tübingen Tübingen Germany
- Institute of Diabetes Research and Metabolic Diseases (IDM) of the Helmholtz Center Munich at the University Tübingen Tübingen Germany
- German Center for Diabetes Research (DZD) at the University Tübingen Tübingen Germany
| |
Collapse
|
12
|
Dandapani MC, Venkatesan V, Charmine P, Geminiganesan S, Ekambaram S. Differential urinary microRNA expression analysis of miR-1, miR-215, miR-335, let-7a in childhood nephrotic syndrome. Mol Biol Rep 2022; 49:6591-6600. [PMID: 35553329 DOI: 10.1007/s11033-022-07500-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2021] [Accepted: 04/21/2022] [Indexed: 10/18/2022]
Abstract
BACKGROUND Recently, urinary exosomal miRNAs are gaining increasing attention as their expression profiles are often associated with specific diseases and they exhibit great potential as noninvasive biomarkers for the diagnosis of various diseases. The present study was aimed to evaluate the expression status of selected miRNAs (miR-1, miR-215-5p, miR-335-5p and let-7a-5p) in urine samples from children with NS [steroid sensitive (SSNS)] and [steroid resistant (SRNS)] along with healthy control group. METHODS MicroRNA isolation was carried out in urine samples collected from SSNS (100 nos), SRNS (100 nos), and healthy controls (50 nos) using MiRNeasy Mini Kit, followed by cDNA conversion for all the four selected miRNAs using Taqman advanced miRNA cDNA synthesis kit and their expression was quantified by Taqman Advanced miRNA assay kits using Real Time PCR Machine and Rotogen-Q in SSNS and SRNS patients and healthy control subjects. RESULTS Quantification of all the four miRNAs (miR-1, mir-215, miR-335, let-7a) were found to be upregulated in both SSNS and SRNS as compared to control group. Further, the comparison of microRNAs within the case groups revealed significant downregulation of three microRNAs-miR-1, miR-215, miR- 335 and upregulation of let-7a in SRNS group as compared to SSNS. The t-test performed for all the four miRNAs was found to be statistically significant. CONCLUSIONS The aberrant expression of all the four microRNAs in both SSNS and SRNS as compared to healthy subjects may serve as novel biomarkers to distinguish between NS and healthy controls. The differential expression of microRNA let-7a is useful to discriminate SSNS and SRNS.
Collapse
Affiliation(s)
- Mohanapriya Chinambedu Dandapani
- Central Research Facility, Faculty of Clinical Research, Sri Ramachandra Institute of Higher Education and Research, No.1 Ramachandra Nagar, Porur, Chennai, Tamil Nadu, 600 116, India.
| | - Vettriselvi Venkatesan
- Department of Human Genetics, Sri Ramachandra Institute of Higher Education and Research, Porur, Chennai, 600 116, India
| | - Pricilla Charmine
- Central Research Facility, Faculty of Clinical Research, Sri Ramachandra Institute of Higher Education and Research, No.1 Ramachandra Nagar, Porur, Chennai, Tamil Nadu, 600 116, India
| | - Sangeetha Geminiganesan
- Department of Pediatric Medicine, Sri Ramachandra Institute of Higher Education and Research, Porur, Chennai, 600 116, India
| | - Sudha Ekambaram
- Department of Pediatric Nephrology, Dr. Mehta's Hospital, Chetpet, Chennai, 600031, India
| |
Collapse
|
13
|
Chen J, Wang X, He Q, Harris RC. TAZ is important for maintenance of the integrity of podocytes. Am J Physiol Renal Physiol 2022; 322:F419-F428. [PMID: 35157550 PMCID: PMC8934679 DOI: 10.1152/ajprenal.00426.2021] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Revised: 02/01/2022] [Accepted: 02/07/2022] [Indexed: 11/22/2022] Open
Abstract
The podocyte is an important component of the glomerular filtration barrier, and maintenance of the integrity of its highly specified structure and function is critical for normal kidney function. Yes-associated protein (YAP)/transcriptional coactivator with PDZ-binding motif (TAZ) are two crucial effectors of the Hippo signaling pathway, and recent studies have shown that podocyte-specific YAP deletion causes podocyte apoptosis and the development of focal segmental glomerulosclerosis followed by progressive renal failure. In the present study, we investigated a potential role of the YAP paralog TAZ in podocytes. TAZ was found to be constitutively active in podocytes, and mice with podocyte-specific deletion of TAZ (TazpodKO) developed proteinuria starting at 4 wk of age and had increased podocyte apoptosis. Using primary cultured podocytes or immortalized mouse podocytes from Tazflox/flox mice, we found that TAZ is a transcriptional activator for TEAD-dependent expression of synaptopodin, zonula occludens-1, and zonula occludens-2. This is the first study to determine that TAZ plays an important role in the maintenance of the structure and function of podocytes.NEW & NOTEWORTHY Podocytes play an important role in maintaining the integrity of the structure and function of the kidney. We observed that mice with selective deletion of transcriptional coactivator with PDZ-binding motif (TAZ) in podocytes developed proteinuria. TAZ is constitutively active and critical for expression of synaptopodin, zonula occludens-1, and zonula occludens-2 in podocytes. The findings of this study implicate TAZ as an important mediator of podocyte structural integrity and provide further insights into the role of Hippo-Yes-associated protein/TAZ in podocyte biology.
Collapse
Affiliation(s)
- Jianchun Chen
- United States Department of Veterans Affairs, Nashville, Tennessee
- Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee
- Vanderbilt Center for Kidney Disease, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Xiaoyong Wang
- Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Qian He
- Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Raymond C Harris
- United States Department of Veterans Affairs, Nashville, Tennessee
- Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee
- Vanderbilt Center for Kidney Disease, Vanderbilt University Medical Center, Nashville, Tennessee
- Department of Molecular Physiology and Biophysics, Vanderbilt University Medical Center, Nashville, Tennessee
| |
Collapse
|
14
|
Paul A, Annunziato S, Lu B, Sun T, Evrova O, Planas-Paz L, Orsini V, Terracciano LM, Charlat O, Loureiro ZY, Ji L, Zamponi R, Sigoillot F, Lei H, Lindeman A, Russ C, Reece-Hoyes JS, Nicholson TB, Tchorz JS, Cong F. Cell adhesion molecule KIRREL1 is a feedback regulator of Hippo signaling recruiting SAV1 to cell-cell contact sites. Nat Commun 2022; 13:930. [PMID: 35177623 PMCID: PMC8854406 DOI: 10.1038/s41467-022-28567-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Accepted: 01/31/2022] [Indexed: 12/11/2022] Open
Abstract
The Hippo/YAP pathway controls cell proliferation through sensing physical and spatial organization of cells. How cell-cell contact is sensed by Hippo signaling is poorly understood. Here, we identified the cell adhesion molecule KIRREL1 as an upstream positive regulator of the mammalian Hippo pathway. KIRREL1 physically interacts with SAV1 and recruits SAV1 to cell-cell contact sites. Consistent with the hypothesis that KIRREL1-mediated cell adhesion suppresses YAP activity, knockout of KIRREL1 increases YAP activity in neighboring cells. Analyzing pan-cancer CRISPR proliferation screen data reveals KIRREL1 as the top plasma membrane protein showing strong correlation with known Hippo regulators, highlighting a critical role of KIRREL1 in regulating Hippo signaling and cell proliferation. During liver regeneration in mice, KIRREL1 is upregulated, and its genetic ablation enhances hepatic YAP activity, hepatocyte reprogramming and biliary epithelial cell proliferation. Our data suggest that KIRREL1 functions as a feedback regulator of the mammalian Hippo pathway through sensing cell-cell interaction and recruiting SAV1 to cell-cell contact sites.
Collapse
Affiliation(s)
- Atanu Paul
- Novartis Institutes for BioMedical Research, Novartis Pharma AG, Cambridge, MA, USA
| | - Stefano Annunziato
- Novartis Institutes for BioMedical Research, Novartis Pharma AG, Basel, Switzerland
| | - Bo Lu
- Novartis Institutes for BioMedical Research, Novartis Pharma AG, Cambridge, MA, USA
| | - Tianliang Sun
- Novartis Institutes for BioMedical Research, Novartis Pharma AG, Basel, Switzerland
| | - Olivera Evrova
- Novartis Institutes for BioMedical Research, Novartis Pharma AG, Basel, Switzerland
| | - Lara Planas-Paz
- Novartis Institutes for BioMedical Research, Novartis Pharma AG, Basel, Switzerland
| | - Vanessa Orsini
- Novartis Institutes for BioMedical Research, Novartis Pharma AG, Basel, Switzerland
| | - Luigi M Terracciano
- Department of Biomedical Sciences, Humanitas University, Pieve Emanuele (Milan), Italy.,IRCCS Humanitas Research Hospital, Rozzano (Milan), Italy
| | - Olga Charlat
- Novartis Institutes for BioMedical Research, Novartis Pharma AG, Cambridge, MA, USA
| | - Zinger Yang Loureiro
- Novartis Institutes for BioMedical Research, Novartis Pharma AG, Cambridge, MA, USA
| | - Lei Ji
- Novartis Institutes for BioMedical Research, Novartis Pharma AG, Cambridge, MA, USA
| | - Raffaella Zamponi
- Novartis Institutes for BioMedical Research, Novartis Pharma AG, Cambridge, MA, USA
| | - Frederic Sigoillot
- Novartis Institutes for BioMedical Research, Novartis Pharma AG, Cambridge, MA, USA
| | - Hong Lei
- Novartis Institutes for BioMedical Research, Novartis Pharma AG, Cambridge, MA, USA
| | - Alicia Lindeman
- Novartis Institutes for BioMedical Research, Novartis Pharma AG, Cambridge, MA, USA
| | - Carsten Russ
- Novartis Institutes for BioMedical Research, Novartis Pharma AG, Cambridge, MA, USA
| | - John S Reece-Hoyes
- Novartis Institutes for BioMedical Research, Novartis Pharma AG, Cambridge, MA, USA
| | - Thomas B Nicholson
- Novartis Institutes for BioMedical Research, Novartis Pharma AG, Cambridge, MA, USA
| | - Jan S Tchorz
- Novartis Institutes for BioMedical Research, Novartis Pharma AG, Basel, Switzerland
| | - Feng Cong
- Novartis Institutes for BioMedical Research, Novartis Pharma AG, Cambridge, MA, USA.
| |
Collapse
|
15
|
Powell DR, Doree DD, DaCosta CM, Platt KA, Brommage R, Buhring L, Revelli JP, Shadoan MK. Mice Lacking Gpr75 are Hypophagic and Thin. Diabetes Metab Syndr Obes 2022; 15:45-58. [PMID: 35023939 PMCID: PMC8743382 DOI: 10.2147/dmso.s342799] [Citation(s) in RCA: 4] [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: 10/05/2021] [Accepted: 12/15/2021] [Indexed: 01/31/2023] Open
Abstract
PURPOSE Humans with haploinsufficiency of GPR75, an orphan GPCR, are thin. Gpr75 knockout (KO) mice are also thin with improved glucose homeostasis. We wanted to confirm these findings in Gpr75 KO mice and determine whether decreased energy intake and/or increased energy expenditure contributed to the thin phenotype. METHODS Gpr75 KO mice were generated by homologous recombination. All studies compared female and male Gpr75 KO mice to their wild type (WT) littermates. Body composition was measured by DXA and QMR technologies. Glucose homeostasis was evaluated by measuring glucose and insulin levels during oral glucose tolerance tests (OGTTs). Food intake was measured in group-housed mice. In singly housed mice, energy expenditure was measured in Oxymax indirect calorimetry chambers, and locomotor activity was measured in Oxymax and Photobeam Activity System chambers. RESULTS In all 12 cohorts of adult female or male mice, Gpr75 KO mice had less body fat; pooled data showed that, compared to WT littermates (n = 103), Gpr75 KO mice (n = 118) had 49% less body fat and 4% less LBM (P < 0.001 for each). KO mice also had 8% less body fat at weaning (P < 0.05), and during the month after weaning as the thin phenotype became more exaggerated, Gpr75 KO mice ate significantly less than, but had energy expenditure and activity levels comparable to, their WT littermates. During OGTTs, Gpr75 KO mice showed improved glucose tolerance (glucose AUC 23% lower in females, P < 0.05, and 26% lower in males, P < 0.001), accompanied by significantly decreased insulin levels and significantly increased insulin sensitivity indices. CONCLUSION Gpr75 KO mice are thin at weaning, are hypophagic as the thin phenotype becomes more exaggerated, and exhibit improved glucose tolerance and insulin sensitivity as healthy-appearing adults. These results suggest that inhibiting GPR75 in obese humans may safely decrease energy intake and body fat while improving glucose tolerance and insulin sensitivity.
Collapse
Affiliation(s)
- David R Powell
- Department of Pharmaceutical Biology, Lexicon Pharmaceuticals, Inc, The Woodlands, TX, USA
- Correspondence: David R Powell Department of Pharmaceutical Biology, Lexicon Pharmaceuticals, Inc., 2445 Technology Forest Boulevard, The Woodlands, TX, 77381, USATel +1 713 249 3972Fax +1 281 863 8115 Email
| | - Deon D Doree
- Department of Pharmaceutical Biology, Lexicon Pharmaceuticals, Inc, The Woodlands, TX, USA
| | - Christopher M DaCosta
- Department of Pharmaceutical Biology, Lexicon Pharmaceuticals, Inc, The Woodlands, TX, USA
| | - Kenneth A Platt
- Department of Molecular Biology, Lexicon Pharmaceuticals, Inc., The Woodlands, TX, USA
| | - Robert Brommage
- Department of Pharmaceutical Biology, Lexicon Pharmaceuticals, Inc, The Woodlands, TX, USA
| | - Lindsey Buhring
- Department of Pharmaceutical Biology, Lexicon Pharmaceuticals, Inc, The Woodlands, TX, USA
| | - Jean-Pierre Revelli
- Department of Pharmaceutical Biology, Lexicon Pharmaceuticals, Inc, The Woodlands, TX, USA
| | - Melanie K Shadoan
- Department of Pharmaceutical Biology, Lexicon Pharmaceuticals, Inc, The Woodlands, TX, USA
| |
Collapse
|
16
|
Steers NJ, Gupta Y, D’Agati VD, Lim TY, DeMaria N, Mo A, Liang J, Stevens KO, Ahram DF, Lam WY, Gagea M, Nagarajan L, Sanna-Cherchi S, Gharavi AG. GWAS in Mice Maps Susceptibility to HIV-Associated Nephropathy to the Ssbp2 Locus. J Am Soc Nephrol 2022; 33:108-120. [PMID: 34893534 PMCID: PMC8763192 DOI: 10.1681/asn.2021040543] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Accepted: 09/27/2021] [Indexed: 02/04/2023] Open
Abstract
BACKGROUND To gain insight into the pathogenesis of collapsing glomerulopathy, a rare form of FSGS that often arises in the setting of viral infections, we performed a genome-wide association study (GWAS) among inbred mouse strains using a murine model of HIV-1 associated nephropathy (HIVAN). METHODS We first generated F1 hybrids between HIV-1 transgenic mice on the FVB/NJ background and 20 inbred laboratory strains. Analysis of histology, BUN, and urinary NGAL demonstrated marked phenotypic variation among the transgenic F1 hybrids, providing strong evidence for host genetic factors in the predisposition to nephropathy. A GWAS in 365 transgenic F1 hybrids generated from these 20 inbred strains was performed. RESULTS We identified a genome-wide significant locus on chromosome 13-C3 and multiple additional suggestive loci. Crossannotation of the Chr. 13 locus, including single-cell transcriptomic analysis of wildtype and HIV-1 transgenic mouse kidneys, nominated Ssbp2 as the most likely candidate gene. Ssbp2 is highly expressed in podocytes, encodes a transcriptional cofactor that interacts with LDB1 and LMX1B, which are both previously implicated in FSGS. Consistent with these data, older Ssbp2 null mice spontaneously develop glomerulosclerosis, tubular casts, interstitial fibrosis, and inflammation, similar to the HIVAN mouse model. CONCLUSIONS These findings demonstrate the utility of GWAS in mice to uncover host genetic factors for rare kidney traits and suggest Ssbp2 as susceptibility gene for HIVAN, potentially acting via the LDB1-LMX1B transcriptional network.
Collapse
Affiliation(s)
- Nicholas J. Steers
- Division of Nephrology, Department of Medicine, Columbia University Irving Medical Center, New York, New York
| | - Yask Gupta
- Division of Nephrology, Department of Medicine, Columbia University Irving Medical Center, New York, New York
| | - Vivette D. D’Agati
- Department of Pathology and Cell Biology, Columbia University Irving Medical Center, New York, New York
| | - Tze Y. Lim
- Division of Nephrology, Department of Medicine, Columbia University Irving Medical Center, New York, New York
| | - Natalia DeMaria
- Division of Nephrology, Department of Medicine, Columbia University Irving Medical Center, New York, New York
| | - Anna Mo
- Division of Nephrology, Department of Medicine, Columbia University Irving Medical Center, New York, New York
| | - Judy Liang
- Division of Nephrology, Department of Medicine, Columbia University Irving Medical Center, New York, New York
| | - Kelsey O. Stevens
- Division of Nephrology, Department of Medicine, Columbia University Irving Medical Center, New York, New York
| | - Dina F. Ahram
- Division of Nephrology, Department of Medicine, Columbia University Irving Medical Center, New York, New York
| | - Wan Yee Lam
- Division of Nephrology, Department of Medicine, Columbia University Irving Medical Center, New York, New York
| | - Mihai Gagea
- Department of Veterinary Medicine and Surgery, University of Texas M.D. Anderson Cancer Center, Houston, Texas
| | - Lalitha Nagarajan
- Department of Genetics, University of Texas M.D. Anderson Cancer Center, Houston, Texas
| | - Simone Sanna-Cherchi
- Division of Nephrology, Department of Medicine, Columbia University Irving Medical Center, New York, New York
| | - Ali G. Gharavi
- Division of Nephrology, Department of Medicine, Columbia University Irving Medical Center, New York, New York
| |
Collapse
|
17
|
Agarwal S, Sudhini YR, Polat OK, Reiser J, Altintas MM. Renal cell markers: lighthouses for managing renal diseases. Am J Physiol Renal Physiol 2021; 321:F715-F739. [PMID: 34632812 DOI: 10.1152/ajprenal.00182.2021] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Kidneys, one of the vital organs in our body, are responsible for maintaining whole body homeostasis. The complexity of renal function (e.g., filtration, reabsorption, fluid and electrolyte regulation, and urine production) demands diversity not only at the level of cell types but also in their overall distribution and structural framework within the kidney. To gain an in depth molecular-level understanding of the renal system, it is imperative to discern the components of kidney and the types of cells residing in each of the subregions. Recent developments in labeling, tracing, and imaging techniques have enabled us to mark, monitor, and identify these cells in vivo with high efficiency in a minimally invasive manner. In this review, we summarize different cell types, specific markers that are uniquely associated with those cell types, and their distribution in the kidney, which altogether make kidneys so special and different. Cellular sorting based on the presence of certain proteins on the cell surface allowed for the assignment of multiple markers for each cell type. However, different studies using different techniques have found contradictions in cell type-specific markers. Thus, the term "cell marker" might be imprecise and suboptimal, leading to uncertainty when interpreting the data. Therefore, we strongly believe that there is an unmet need to define the best cell markers for a cell type. Although the compendium of renal-selective marker proteins presented in this review is a resource that may be useful to researchers, we acknowledge that the list may not be necessarily exhaustive.
Collapse
Affiliation(s)
- Shivangi Agarwal
- Department of Internal Medicine, Rush University, Chicago, Illinois
| | | | - Onur K Polat
- Department of Internal Medicine, Rush University, Chicago, Illinois
| | - Jochen Reiser
- Department of Internal Medicine, Rush University, Chicago, Illinois
| | | |
Collapse
|
18
|
Atienza-Manuel A, Castillo-Mancho V, De Renzis S, Culi J, Ruiz-Gómez M. Endocytosis mediated by an atypical CUBAM complex modulates slit diaphragm dynamics in nephrocytes. Development 2021; 148:272711. [PMID: 34738617 PMCID: PMC8710305 DOI: 10.1242/dev.199894] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Accepted: 10/22/2021] [Indexed: 01/14/2023]
Abstract
The vertebrate endocytic receptor CUBAM, consisting of three cubilin monomers complexed with a single amnionless molecule, plays a major role in protein reabsorption in the renal proximal tubule. Here, we show that Drosophila CUBAM is a tripartite complex composed of Amnionless and two cubilin paralogues, Cubilin and Cubilin2, and that it is required for nephrocyte slit diaphragm (SD) dynamics. Loss of CUBAM-mediated endocytosis induces dramatic morphological changes in nephrocytes and promotes enlarged ingressions of the external membrane and SD mislocalisation. These phenotypes result in part from an imbalance between endocytosis, which is strongly impaired in CUBAM mutants, and exocytosis in these highly active cells. Of note, rescuing receptor-mediated endocytosis by Megalin/LRP2 or Rab5 expression only partially restores SD positioning in CUBAM mutants, suggesting a specific requirement of CUBAM in SD degradation and/or recycling. This finding and the reported expression of CUBAM in podocytes suggest a possible unexpected conserved role for this endocytic receptor in vertebrate SD remodelling. Summary: A genetic study revealing that endocytosis mediated by an atypical CUBAM endocytic receptor, composed of Amnionless and two Cubilin paralogues, regulates slit diaphragm remodelling in Drosophila nephrocytes.
Collapse
Affiliation(s)
- Alexandra Atienza-Manuel
- Centro de Biología Molecular Severo Ochoa, CSIC and UAM, Nicolás Cabrera 1, Cantoblanco 28049, Madrid, Spain
| | - Vicente Castillo-Mancho
- Centro de Biología Molecular Severo Ochoa, CSIC and UAM, Nicolás Cabrera 1, Cantoblanco 28049, Madrid, Spain
| | - Stefano De Renzis
- European Molecular Biology Laboratory (EMBL), Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Joaquim Culi
- Centro de Biología Molecular Severo Ochoa, CSIC and UAM, Nicolás Cabrera 1, Cantoblanco 28049, Madrid, Spain
| | - Mar Ruiz-Gómez
- Centro de Biología Molecular Severo Ochoa, CSIC and UAM, Nicolás Cabrera 1, Cantoblanco 28049, Madrid, Spain
| |
Collapse
|
19
|
Wang J, Vaddadi N, Pak JS, Park Y, Quilez S, Roman CA, Dumontier E, Thornton JW, Cloutier JF, Özkan E. Molecular and structural basis of olfactory sensory neuron axon coalescence by Kirrel receptors. Cell Rep 2021; 37:109940. [PMID: 34731636 PMCID: PMC8628261 DOI: 10.1016/j.celrep.2021.109940] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Revised: 07/30/2021] [Accepted: 10/13/2021] [Indexed: 01/21/2023] Open
Abstract
Projections from sensory neurons of olfactory systems coalesce into glomeruli in the brain. The Kirrel receptors are believed to homodimerize via their ectodomains and help separate sensory neuron axons into Kirrel2- or Kirrel3-expressing glomeruli. Here, we present the crystal structures of homodimeric Kirrel receptors and show that the closely related Kirrel2 and Kirrel3 have evolved specific sets of polar and hydrophobic interactions, respectively, disallowing heterodimerization while preserving homodimerization, likely resulting in proper segregation and coalescence of Kirrel-expressing axons into glomeruli. We show that the dimerization interface at the N-terminal immunoglobulin (IG) domains is necessary and sufficient to create homodimers and fail to find evidence for a secondary interaction site in Kirrel ectodomains. Furthermore, we show that abolishing dimerization of Kirrel3 in vivo leads to improper formation of glomeruli in the mouse accessory olfactory bulb as observed in Kirrel3-/- animals. Our results provide evidence for Kirrel3 homodimerization controlling axonal coalescence.
Collapse
Affiliation(s)
- Jing Wang
- Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL 60637, USA; Grossman Institute for Neuroscience, Quantitative Biology and Human Behavior, The University of Chicago, Chicago, IL 60637, USA
| | - Neelima Vaddadi
- The Neuro-Montreal Neurological Institute and Hospital, McGill University, Montréal, QC H3A 2B4, Canada; Department of Neurology and Neurosurgery, McGill University, Montréal, QC H3A 2B4, Canada
| | - Joseph S Pak
- Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL 60637, USA; Grossman Institute for Neuroscience, Quantitative Biology and Human Behavior, The University of Chicago, Chicago, IL 60637, USA
| | - Yeonwoo Park
- Committee on Genetics, Genomics and Systems Biology, The University of Chicago, Chicago, IL 60637, USA
| | - Sabrina Quilez
- The Neuro-Montreal Neurological Institute and Hospital, McGill University, Montréal, QC H3A 2B4, Canada; Department of Neurology and Neurosurgery, McGill University, Montréal, QC H3A 2B4, Canada
| | - Christina A Roman
- Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL 60637, USA
| | - Emilie Dumontier
- The Neuro-Montreal Neurological Institute and Hospital, McGill University, Montréal, QC H3A 2B4, Canada
| | - Joseph W Thornton
- Committee on Genetics, Genomics and Systems Biology, The University of Chicago, Chicago, IL 60637, USA; Department of Human Genetics, The University of Chicago, Chicago, IL 60637, USA; Department of Ecology and Evolution, The University of Chicago, Chicago, IL 60637, USA
| | - Jean-François Cloutier
- The Neuro-Montreal Neurological Institute and Hospital, McGill University, Montréal, QC H3A 2B4, Canada; Department of Neurology and Neurosurgery, McGill University, Montréal, QC H3A 2B4, Canada; Department of Anatomy and Cell Biology, McGill University, Montréal, QC H3A 0C7, Canada.
| | - Engin Özkan
- Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL 60637, USA; Grossman Institute for Neuroscience, Quantitative Biology and Human Behavior, The University of Chicago, Chicago, IL 60637, USA.
| |
Collapse
|
20
|
Afsar B, Afsar RE, Demiray A, Covic A, Kanbay M. Deciphering nutritional interventions for podocyte structure and function. Pharmacol Res 2021; 172:105852. [PMID: 34450318 DOI: 10.1016/j.phrs.2021.105852] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Revised: 08/22/2021] [Accepted: 08/22/2021] [Indexed: 12/11/2022]
Abstract
Despite increasing awareness and therapeutic options chronic kidney disease (CKD) is still and important health problem and glomerular diseases constitute and important percentage of CKD. Proteinuria/albuminuria is not just a marker; but it also plays a direct pathogenic role in renal disease progression of CKD. Glomerular filtration barrier (GFB) which consists of fenestrated endothelial cells, fused basal membrane and interdigitating podocyte foot process and filtration slits between foot process is the major barrier for proteinuria/albuminuria. Many glomerular diseases are characterized by disruption of GFB podocytes, foot process and slit diaphragm. Many proteinuric diseases are non-specifically targeted by therapeutic agents such as steroids and calcineurin inhibitors with systemic side effects. Thus, there is unmet need for more efficient and less toxic therapeutic options to treat glomerular diseases. In recent years, modification of dietary intake, has been gained to treat pathologic processes introducing the concept of 'food as a medicine'. The effect of various nutritional products on podocyte function and structure is also trending, especially in recent years. In the current review, we summarized the effect of nutritional interventions on podocyte function and structure.
Collapse
Affiliation(s)
- Baris Afsar
- Division of Nephrology, Department of Nephrology, Suleyman Demirel University School of Medicine, Isparta, Turkey.
| | - Rengin Elsurer Afsar
- Division of Nephrology, Department of Nephrology, Suleyman Demirel University School of Medicine, Isparta, Turkey
| | - Atalay Demiray
- Department of Medicine, Koc University School of Medicine, Istanbul, Turkey
| | - Adrian Covic
- Department of Nephrology, Grigore T. Popa' University of Medicine, Iasi, Romania
| | - Mehmet Kanbay
- Division of Nephrology, Department of Medicine, Koc University School of Medicine, Istanbul, Turkey
| |
Collapse
|
21
|
Powell DR, Revelli JP, Doree DD, DaCosta CM, Desai U, Shadoan MK, Rodriguez L, Mullens M, Yang QM, Ding ZM, Kirkpatrick LL, Vogel P, Zambrowicz B, Sands AT, Platt KA, Hansen GM, Brommage R. High-Throughput Screening of Mouse Gene Knockouts Identifies Established and Novel High Body Fat Phenotypes. Diabetes Metab Syndr Obes 2021; 14:3753-3785. [PMID: 34483672 PMCID: PMC8409770 DOI: 10.2147/dmso.s322083] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Accepted: 08/04/2021] [Indexed: 01/05/2023] Open
Abstract
PURPOSE Obesity is a major public health problem. Understanding which genes contribute to obesity may better predict individual risk and allow development of new therapies. Because obesity of a mouse gene knockout (KO) line predicts an association of the orthologous human gene with obesity, we reviewed data from the Lexicon Genome5000TM high throughput phenotypic screen (HTS) of mouse gene KOs to identify KO lines with high body fat. MATERIALS AND METHODS KO lines were generated using homologous recombination or gene trapping technologies. HTS body composition analyses were performed on adult wild-type and homozygous KO littermate mice from 3758 druggable mouse genes having a human ortholog. Body composition was measured by either DXA or QMR on chow-fed cohorts from all 3758 KO lines and was measured by QMR on independent high fat diet-fed cohorts from 2488 of these KO lines. Where possible, comparisons were made to HTS data from the International Mouse Phenotyping Consortium (IMPC). RESULTS Body fat data are presented for 75 KO lines. Of 46 KO lines where independent external published and/or IMPC KO lines are reported as obese, 43 had increased body fat. For the remaining 29 novel high body fat KO lines, Ksr2 and G2e3 are supported by data from additional independent KO cohorts, 6 (Asnsd1, Srpk2, Dpp8, Cxxc4, Tenm3 and Kiss1) are supported by data from additional internal cohorts, and the remaining 21 including Tle4, Ak5, Ntm, Tusc3, Ankk1, Mfap3l, Prok2 and Prokr2 were studied with HTS cohorts only. CONCLUSION These data support the finding of high body fat in 43 independent external published and/or IMPC KO lines. A novel obese phenotype was identified in 29 additional KO lines, with 27 still lacking the external confirmation now provided for Ksr2 and G2e3 KO mice. Undoubtedly, many mammalian obesity genes remain to be identified and characterized.
Collapse
Affiliation(s)
- David R Powell
- Department of Pharmaceutical Biology, Lexicon Pharmaceuticals, Inc, The Woodlands, TX, USA
| | - Jean-Pierre Revelli
- Department of Pharmaceutical Biology, Lexicon Pharmaceuticals, Inc, The Woodlands, TX, USA
| | - Deon D Doree
- Department of Pharmaceutical Biology, Lexicon Pharmaceuticals, Inc, The Woodlands, TX, USA
| | - Christopher M DaCosta
- Department of Pharmaceutical Biology, Lexicon Pharmaceuticals, Inc, The Woodlands, TX, USA
| | - Urvi Desai
- Department of Pharmaceutical Biology, Lexicon Pharmaceuticals, Inc, The Woodlands, TX, USA
| | - Melanie K Shadoan
- Department of Pharmaceutical Biology, Lexicon Pharmaceuticals, Inc, The Woodlands, TX, USA
| | - Lawrence Rodriguez
- Department of Information Technology, Lexicon Pharmaceuticals, Inc, The Woodlands, Tx, USA
| | - Michael Mullens
- Department of Information Technology, Lexicon Pharmaceuticals, Inc, The Woodlands, Tx, USA
| | - Qi M Yang
- Department of Pharmaceutical Biology, Lexicon Pharmaceuticals, Inc, The Woodlands, TX, USA
| | - Zhi-Ming Ding
- Department of Pharmaceutical Biology, Lexicon Pharmaceuticals, Inc, The Woodlands, TX, USA
| | - Laura L Kirkpatrick
- Department of Molecular Biology, Lexicon Pharmaceuticals, Inc, The Woodlands, Tx, USA
| | - Peter Vogel
- Department of Pharmaceutical Biology, Lexicon Pharmaceuticals, Inc, The Woodlands, TX, USA
| | - Brian Zambrowicz
- Department of Pharmaceutical Biology, Lexicon Pharmaceuticals, Inc, The Woodlands, TX, USA
- Department of Information Technology, Lexicon Pharmaceuticals, Inc, The Woodlands, Tx, USA
- Department of Molecular Biology, Lexicon Pharmaceuticals, Inc, The Woodlands, Tx, USA
| | - Arthur T Sands
- Department of Pharmaceutical Biology, Lexicon Pharmaceuticals, Inc, The Woodlands, TX, USA
- Department of Information Technology, Lexicon Pharmaceuticals, Inc, The Woodlands, Tx, USA
- Department of Molecular Biology, Lexicon Pharmaceuticals, Inc, The Woodlands, Tx, USA
| | - Kenneth A Platt
- Department of Molecular Biology, Lexicon Pharmaceuticals, Inc, The Woodlands, Tx, USA
| | - Gwenn M Hansen
- Department of Molecular Biology, Lexicon Pharmaceuticals, Inc, The Woodlands, Tx, USA
| | - Robert Brommage
- Department of Pharmaceutical Biology, Lexicon Pharmaceuticals, Inc, The Woodlands, TX, USA
| |
Collapse
|
22
|
Ivanov V, Fukusumi Y, Zhang Y, Yasuda H, Kitazawa M, Kawachi H. Synbindin Downregulation Participates in Slit Diaphragm Dysfunction. Am J Nephrol 2021; 52:620-629. [PMID: 34515036 DOI: 10.1159/000517975] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Accepted: 06/01/2021] [Indexed: 11/19/2022]
Abstract
INTRODUCTION Synbindin, originally identified as a neuronal cytoplasmic molecule, was found in glomeruli. The cDNA subtractive hybridization technique showed the mRNA expression of synbindin in glomeruli was downregulated in puromycin aminonucleoside (PAN) nephropathy, a mimic of minimal-change nephrotic syndrome. METHODS The expression of synbindin in podocytes was analyzed in normal rats and 2 types of rat nephrotic models, anti-nephrin antibody-induced nephropathy, a pure slit diaphragm injury model, and PAN nephropathy, by immunohistochemical analysis and RT-PCR techniques. To elucidate the function of synbindin, a gene silencing study with human cultured podocytes was performed. RESULTS Synbindin was mainly expressed at the slit diaphragm area of glomerular epithelial cells (podocytes). In both nephrotic models, decreased mRNA expression and the altered staining of synbindin were already detected at the early phase when proteinuria and the altered staining of nephrin, a key molecule of slit diaphragm, were not detected yet. Synbindin staining was clearly reduced when severe proteinuria was observed. When the cultured podocytes were treated with siRNA for synbindin, the cell changed to a round shape, and filamentous actin structure was clearly altered. The expression of ephrin-B1, a transmembrane protein at slit diaphragm, was clearly lowered, and synaptic vesicle-associated protein 2B (SV2B) was upregulated in the synbindin knockdown cells. CONCLUSION Synbindin participates in maintaining foot processes and slit diaphragm as a downstream molecule of SV2B-mediated vesicle transport. Synbindin downregulation participates in slit diaphragm dysfunction. Synbindin can be an early marker to detect podocyte injury.
Collapse
Affiliation(s)
- Veniamin Ivanov
- Department of Cell Biology, Kidney Research Center, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Yoshiyasu Fukusumi
- Department of Cell Biology, Kidney Research Center, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Ying Zhang
- Department of Cell Biology, Kidney Research Center, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Hidenori Yasuda
- Department of Cell Biology, Kidney Research Center, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Meiko Kitazawa
- Department of Cell Biology, Kidney Research Center, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Hiroshi Kawachi
- Department of Cell Biology, Kidney Research Center, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| |
Collapse
|
23
|
Solanki AK, Arif E, Srivastava P, Furcht CM, Rahman B, Wen P, Singh A, Holzman LB, Fitzgibbon WR, Budisavljevic MN, Lobo GP, Kwon SH, Han Z, Lazzara MJ, Lipschutz JH, Nihalani D. Phosphorylation of slit diaphragm proteins NEPHRIN and NEPH1 upon binding of HGF promotes podocyte repair. J Biol Chem 2021; 297:101079. [PMID: 34391780 PMCID: PMC8429977 DOI: 10.1016/j.jbc.2021.101079] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Revised: 08/02/2021] [Accepted: 08/11/2021] [Indexed: 12/22/2022] Open
Abstract
Phosphorylation (activation) and dephosphorylation (deactivation) of the slit diaphragm proteins NEPHRIN and NEPH1 are critical for maintaining the kidney epithelial podocyte actin cytoskeleton and, therefore, proper glomerular filtration. However, the mechanisms underlying these events remain largely unknown. Here we show that NEPHRIN and NEPH1 are novel receptor proteins for hepatocyte growth factor (HGF) and can be phosphorylated independently of the mesenchymal epithelial transition receptor in a ligand-dependent fashion through engagement of their extracellular domains by HGF. Furthermore, we demonstrate SH2 domain–containing protein tyrosine phosphatase-2–dependent dephosphorylation of these proteins. To establish HGF as a ligand, purified baculovirus-expressed NEPHRIN and NEPH1 recombinant proteins were used in surface plasma resonance binding experiments. We report high-affinity interactions of NEPHRIN and NEPH1 with HGF, although NEPHRIN binding was 20-fold higher than that of NEPH1. In addition, using molecular modeling we constructed peptides that were used to map specific HGF-binding regions in the extracellular domains of NEPHRIN and NEPH1. Finally, using an in vitro model of cultured podocytes and an ex vivo model of Drosophila nephrocytes, as well as chemically induced injury models, we demonstrated that HGF-induced phosphorylation of NEPHRIN and NEPH1 is centrally involved in podocyte repair. Taken together, this is the first study demonstrating a receptor-based function for NEPHRIN and NEPH1. This has important biological and clinical implications for the repair of injured podocytes and the maintenance of podocyte integrity.
Collapse
Affiliation(s)
- Ashish K Solanki
- Department of Medicine, Medical University of South Carolina, Charleston, South Carolina, USA
| | - Ehtesham Arif
- Department of Medicine, Medical University of South Carolina, Charleston, South Carolina, USA
| | - Pankaj Srivastava
- Department of Biochemistry and Molecular Genetics, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
| | - Christopher M Furcht
- Department of Chemical and Biomolecular Engineering, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Bushra Rahman
- Department of Medicine, Medical University of South Carolina, Charleston, South Carolina, USA
| | - Pei Wen
- Department of Medicine, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Avinash Singh
- Department of Medicine, Medical University of South Carolina, Charleston, South Carolina, USA
| | - Lawrence B Holzman
- Department of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Wayne R Fitzgibbon
- Department of Medicine, Medical University of South Carolina, Charleston, South Carolina, USA
| | - Milos N Budisavljevic
- Department of Medicine, Medical University of South Carolina, Charleston, South Carolina, USA
| | - Glenn P Lobo
- Department of Medicine, Medical University of South Carolina, Charleston, South Carolina, USA
| | - Sang-Ho Kwon
- Department of Cellular Biology and Anatomy, Augusta University, Augusta, Georgia, USA
| | - Zhe Han
- Department of Medicine, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Matthew J Lazzara
- Department of Chemical Engineering, University of Virginia, Charlottesville, Virginia, USA
| | - Joshua H Lipschutz
- Department of Medicine, Medical University of South Carolina, Charleston, South Carolina, USA; Department of Medicine, Ralph H. Johnson Veterans Affairs Medical Center, Charleston, South Carolina, USA.
| | - Deepak Nihalani
- Division of Kidney, Urologic and Hematologic Diseases, National Institutes of Health, Bethesda, Maryland, USA
| |
Collapse
|
24
|
Wang D, Sant S, Ferrell N. A Biomimetic In Vitro Model of the Kidney Filtration Barrier Using Tissue-Derived Glomerular Basement Membrane. Adv Healthc Mater 2021; 10:e2002275. [PMID: 34218528 DOI: 10.1002/adhm.202002275] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Revised: 05/24/2021] [Indexed: 01/28/2023]
Abstract
The glomerular filtration barrier (GFB) filters the blood to remove toxins while retaining high molecular weight proteins in the circulation. The glomerular basement membrane (GBM) and podocytes, highly specialized epithelial cells, are critical components of the filtration barrier. The GBM serves as a physical barrier to passage of molecules into the filtrate. Podocytes adhere to the filtrate side of the GBM and further restrict passage of high molecular weight molecules into the filtrate. Here, a 3D cell culture model of the glomerular filtration barrier to evaluate the role of the GBM and podocytes in mediating molecular diffusion is developed. GBM is isolated from mammalian kidneys to recapitulate the composition and mechanics of the in vivo basement membrane. The GFB model exhibits molecular selectivity that is comparable to the in vivo filtration barrier. The GBM alone provides a stringent barrier to passage of albumin and Ficoll. Podocytes further restrict molecular diffusion. Damage to the GBM that is typical of diabetic kidney disease is simulated using hypochlorous acid and results in increased molecular diffusion. This system can serve as a platform to evaluate the effects of GBM damage, podocyte injury, and reciprocal effects of altered podocyte-GBM interactions on kidney microvascular permeability.
Collapse
Affiliation(s)
- Dan Wang
- Department of Medicine, Division of Nephrology, Vanderbilt University Medical Center, 1161 21st Ave. South, Nashville, TN, 37232, USA
| | - Snehal Sant
- Department of Medicine, Division of Nephrology, Vanderbilt University Medical Center, 1161 21st Ave. South, Nashville, TN, 37232, USA
| | - Nicholas Ferrell
- Department of Medicine, Division of Nephrology, Vanderbilt University Medical Center, 1161 21st Ave. South, Nashville, TN, 37232, USA
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, 37235, USA
- Vanderbilt Center for Kidney Disease, S3223 Medical Center North, Nashville, TN, 37232, USA
| |
Collapse
|
25
|
Mulukala SKN, Kambhampati V, Qadri AH, Pasupulati AK. Evolutionary conservation of intrinsically unstructured regions in slit-diaphragm proteins. PLoS One 2021; 16:e0254917. [PMID: 34288970 PMCID: PMC8294545 DOI: 10.1371/journal.pone.0254917] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2021] [Accepted: 07/06/2021] [Indexed: 01/19/2023] Open
Abstract
Vertebrate kidneys contribute to homeostasis by regulating electrolyte, acid-base balance, removing toxic metabolites from blood, and preventing protein loss into the urine. Glomerular podocytes constitute the blood-urine barrier, and podocyte slit-diaphragm (SD), a modified tight junction, contributes to the glomerular permselectivity. Nephrin, KIRREL1, podocin, CD2AP, and TRPC6 are crucial members of the SD that interact with each other and contribute to the SD's structural and functional integrity. This study analyzed the distribution of these five essential SD proteins across the organisms for which the genome sequence is available. We found a diverse distribution of nephrin and KIRREL1 ranging from nematodes to higher vertebrates, whereas podocin, CD2AP, and TRPC6 are restricted to the vertebrates. Among invertebrates, nephrin and its orthologs consist of more immunoglobulin-3 domains, whereas in the vertebrates, CD80-like C2-set domains are predominant. In the case of KIRREL1 and its orthologs, more Ig domains were observed in invertebrates than vertebrates. Src Homology-3 (SH3) domain of CD2AP and SPFH domain of podocin are highly conserved among vertebrates. TRPC6 and its orthologs had conserved ankyrin repeats, TRP, and ion transport domains, except Chondrichthyes and Echinodermata, which do not possess the ankyrin repeats. Intrinsically unstructured regions (IURs) are conserved across the SD orthologs, suggesting IURs importance in the protein complexes that constitute the slit-diaphragm. For the first time, a study reports the evolutionary insights of vertebrate SD proteins and their invertebrate orthologs.
Collapse
Affiliation(s)
- Sandeep K N Mulukala
- Department of Biochemistry, School of Life Sciences, University of Hyderabad, Hyderabad, India
| | - Vaishnavi Kambhampati
- Department of Biochemistry, School of Life Sciences, University of Hyderabad, Hyderabad, India
| | - Abrar H Qadri
- Department of Biochemistry, School of Life Sciences, University of Hyderabad, Hyderabad, India
| | - Anil K Pasupulati
- Department of Biochemistry, School of Life Sciences, University of Hyderabad, Hyderabad, India
| |
Collapse
|
26
|
Tesch F, Siegerist F, Hay E, Artelt N, Daniel C, Amann K, Zimmermann U, Kavvadas P, Grisk O, Chadjichristos C, Endlich K, Chatziantoniou C, Endlich N. Super-resolved local recruitment of CLDN5 to filtration slits implicates a direct relationship with podocyte foot process effacement. J Cell Mol Med 2021; 25:7631-7641. [PMID: 34156149 PMCID: PMC8358871 DOI: 10.1111/jcmm.16519] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Revised: 03/22/2021] [Accepted: 03/24/2021] [Indexed: 11/28/2022] Open
Abstract
Under healthy conditions, foot processes of neighbouring podocytes are interdigitating and connected by an electron‐dense slit diaphragm. Besides slit diaphragm proteins, typical adherens junction proteins are also found to be expressed at this cell‐cell junction. It is therefore considered as a highly specialized type of adherens junction. During podocyte injury, podocyte foot processes lose their characteristic 3D structure and the filtration slits typical meandering structure gets linearized. It is still under debate how this change of structure leads to the phenomenon of proteinuria. Using super‐resolution 3D‐structured illumination microscopy, we observed a spatially restricted up‐regulation of the tight junction protein claudin‐5 (CLDN5) in areas where podocyte processes of patients suffering from minimal change disease (MCD), focal and segmental glomerulosclerosis (FSGS) as well as in murine nephrotoxic serum (NTS) nephritis and uninephrectomy DOCA‐salt hypertension models, were locally injured. CLDN5/nephrin ratios in human glomerulopathies and NTS‐treated mice were significantly higher compared to controls. In patients, the CLDN5/nephrin ratio is significantly correlated with the filtration slit density as a foot process effacement marker, confirming a direct association of local CLDN5 up‐regulation in injured foot processes. Moreover, CLDN5 up‐regulation was observed in some areas of high filtration slit density, suggesting that CLND5 up‐regulation preceded the changes of foot processes. Therefore, CLDN5 could serve as a biomarker predicting early foot process effacement.
Collapse
Affiliation(s)
- Florian Tesch
- Department of Anatomy and Cell Biology, University Medicine Greifswald, Greifswald, Germany
| | - Florian Siegerist
- Department of Anatomy and Cell Biology, University Medicine Greifswald, Greifswald, Germany
| | - Eleonora Hay
- Department of Anatomy and Cell Biology, University Medicine Greifswald, Greifswald, Germany.,Department of Mental and Physical Health and Preventive Medicine, Section of Human Anatomy, University of Campania "Luigi Vanvitelli", Naples, Italy
| | - Nadine Artelt
- Department of Anatomy and Cell Biology, University Medicine Greifswald, Greifswald, Germany
| | - Christoph Daniel
- Department of Nephropathology, Institute of Pathology, University of Erlangen-Nuremberg, Erlangen, Germany
| | - Kerstin Amann
- Department of Nephropathology, Institute of Pathology, University of Erlangen-Nuremberg, Erlangen, Germany
| | - Uwe Zimmermann
- Department of Urology, University Medicine Greifswald, Greifswald, Germany
| | | | - Olaf Grisk
- Institute for Physiology, Medizinische Hochschule Brandenburg Theodor Fontane, Neuruppin, Germany
| | | | - Karlhans Endlich
- Department of Anatomy and Cell Biology, University Medicine Greifswald, Greifswald, Germany
| | | | - Nicole Endlich
- Department of Anatomy and Cell Biology, University Medicine Greifswald, Greifswald, Germany
| |
Collapse
|
27
|
Fukusumi Y, Yasuda H, Zhang Y, Kawachi H. Nephrin-Ephrin-B1-Na +/H + Exchanger Regulatory Factor 2-Ezrin-Actin Axis Is Critical in Podocyte Injury. THE AMERICAN JOURNAL OF PATHOLOGY 2021; 191:1209-1226. [PMID: 33887216 DOI: 10.1016/j.ajpath.2021.04.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Revised: 03/13/2021] [Accepted: 04/05/2021] [Indexed: 10/21/2022]
Abstract
Ephrin-B1 is one of the critical components of the slit diaphragm of kidney glomerular podocyte. However, the precise function of ephrin-B1 is unclear. To clarify the function of ephrin-B1, ephrin-B1-associated molecules were studied. RNA-sequencing analysis suggested that Na+/H+ exchanger regulatory factor 2 (NHERF2), a scaffolding protein, is associated with ephrin-B1. NHERF2 was expressed at the apical area and the slit diaphragm, and interacted with the nephrin-ephrin-B1 complex at the slit diaphragm. The nephrin-ephrin-B1-NHERF2 complex interacted with ezrin bound to F-actin. NHERF2 bound ephrin-B1 via its first postsynaptic density protein-95/disks large/zonula occludens-1 domain, and podocalyxin via its second postsynaptic density protein-95/disks large/zonula occludens-1 domain. Both in vitro analyses with human embryonic kidney 293 cells and in vivo study with rat nephrotic model showed that stimulaiton of the slit diaphragm, phosphorylation of nephrin and ephrin-B1, and dephosphorylation of NHERF2 and ezrin, disrupted the linkages of ephrin-B1-NHERF2 and NHERF2-ezrin. It is conceivable that the linkage of nephrin-ephrin-B1-NHERF2-ezrin-actin is a novel critical axis in the podocytes. Ephrin-B1 phosphorylation also disrupted the linkage of an apical transmembrane protein, podocalyxin, with NHERF2-ezrin-actin. The phosphorylation of ephrin-B1 and the consequent dephosphorylation of NHERF2 are critical initiation events leading to podocyte injury.
Collapse
Affiliation(s)
- Yoshiyasu Fukusumi
- Department of Cell Biology, Kidney Research Center, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Hidenori Yasuda
- Department of Cell Biology, Kidney Research Center, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Ying Zhang
- Department of Cell Biology, Kidney Research Center, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Hiroshi Kawachi
- Department of Cell Biology, Kidney Research Center, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan.
| |
Collapse
|
28
|
Haddad G, Lorenzen JM, Ma H, de Haan N, Seeger H, Zaghrini C, Brandt S, Kölling M, Wegmann U, Kiss B, Pál G, Gál P, Wüthrich RP, Wuhrer M, Beck LH, Salant DJ, Lambeau G, Kistler AD. Altered glycosylation of IgG4 promotes lectin complement pathway activation in anti-PLA2R1-associated membranous nephropathy. J Clin Invest 2021; 131:140453. [PMID: 33351779 DOI: 10.1172/jci140453] [Citation(s) in RCA: 84] [Impact Index Per Article: 28.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Accepted: 12/16/2020] [Indexed: 12/19/2022] Open
Abstract
Primary membranous nephropathy (pMN) is a leading cause of nephrotic syndrome in adults. In most cases, this autoimmune kidney disease is associated with autoantibodies against the M-type phospholipase A2 receptor (PLA2R1) expressed on kidney podocytes, but the mechanisms leading to glomerular damage remain elusive. Here, we developed a cell culture model using human podocytes and found that anti-PLA2R1-positive pMN patient sera or isolated IgG4, but not IgG4-depleted sera, induced proteolysis of the 2 essential podocyte proteins synaptopodin and NEPH1 in the presence of complement, resulting in perturbations of the podocyte cytoskeleton. Specific blockade of the lectin pathway prevented degradation of synaptopodin and NEPH1. Anti-PLA2R1 IgG4 directly bound mannose-binding lectin in a glycosylation-dependent manner. In a cohort of pMN patients, we identified increased levels of galactose-deficient IgG4, which correlated with anti-PLA2R1 titers and podocyte damage induced by patient sera. Assembly of the terminal C5b-9 complement complex and activation of the complement receptors C3aR1 or C5aR1 were required to induce proteolysis of synaptopodin and NEPH1 by 2 distinct proteolytic pathways mediated by cysteine and aspartic proteinases, respectively. Together, these results demonstrated a mechanism by which aberrantly glycosylated IgG4 activated the lectin pathway and induced podocyte injury in primary membranous nephropathy.
Collapse
Affiliation(s)
- George Haddad
- Institute of Physiology, University of Zurich, Switzerland.,Division of Nephrology, University Hospital of Zurich, Switzerland
| | - Johan M Lorenzen
- Institute of Physiology, University of Zurich, Switzerland.,Division of Nephrology, University Hospital of Zurich, Switzerland
| | - Hong Ma
- Department of Medicine, Boston University School of Medicine, Boston, Massachusetts, USA
| | - Noortje de Haan
- Center for Proteomics and Metabolomics, Leiden University Medical Center, Netherlands
| | - Harald Seeger
- Institute of Physiology, University of Zurich, Switzerland.,Division of Nephrology, University Hospital of Zurich, Switzerland
| | - Christelle Zaghrini
- Université Côte d'Azur, CNRS, Institut de Pharmacologie Moléculaire et Cellulaire, Valbonne Sophia Antipolis, France
| | - Simone Brandt
- Institute of Pathology, University Hospital of Zurich, Switzerland
| | - Malte Kölling
- Institute of Physiology, University of Zurich, Switzerland
| | - Urs Wegmann
- Institute of Physiology, University of Zurich, Switzerland
| | - Bence Kiss
- Department of Biochemistry, Eötvös Loránd University, Budapest, Hungary
| | - Gábor Pál
- Department of Biochemistry, Eötvös Loránd University, Budapest, Hungary
| | - Péter Gál
- Institute of Enzymology, Research Centre for Natural Sciences, Budapest, Hungary
| | - Rudolf P Wüthrich
- Institute of Physiology, University of Zurich, Switzerland.,Division of Nephrology, University Hospital of Zurich, Switzerland
| | - Manfred Wuhrer
- Center for Proteomics and Metabolomics, Leiden University Medical Center, Netherlands
| | - Laurence H Beck
- Department of Medicine, Boston University School of Medicine, Boston, Massachusetts, USA
| | - David J Salant
- Department of Medicine, Boston University School of Medicine, Boston, Massachusetts, USA
| | - Gérard Lambeau
- Université Côte d'Azur, CNRS, Institut de Pharmacologie Moléculaire et Cellulaire, Valbonne Sophia Antipolis, France
| | - Andreas D Kistler
- Institute of Physiology, University of Zurich, Switzerland.,Division of Nephrology, University Hospital of Zurich, Switzerland.,Department of Medicine, Cantonal Hospital Frauenfeld, Switzerland
| |
Collapse
|
29
|
Egerman MA, Wong JS, Runxia T, Mosoyan G, Chauhan K, Reyes-Bahamonde J, Anandakrishnan N, Wong NJ, Bagiella E, Salem F, Meliambro K, Li H, Azeloglu EU, Coca SG, Campbell KN, Raij L. Plasminogenuria is associated with podocyte injury, edema, and kidney dysfunction in incident glomerular disease. FASEB J 2020; 34:16191-16204. [PMID: 33070369 PMCID: PMC7686123 DOI: 10.1096/fj.202000413r] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Revised: 09/25/2020] [Accepted: 09/28/2020] [Indexed: 01/07/2023]
Abstract
Urinary plasminogen/plasmin, or plasmin (ogen) uria, has been demonstrated in proteinuric patients and exposure of cultured podocytes to plasminogen results in injury via oxidative stress pathways. A causative role for plasmin (ogen) as a "second hit" in kidney disease progression has yet to have been demonstrated in vivo. Additionally, association between plasmin (ogen) uria and kidney function in glomerular diseases remains unclear. We performed comparative studies in a puromycin aminonucleoside (PAN) nephropathy rat model treated with amiloride, an inhibitor of plasminogen activation, and measured changes in plasmin (ogen) uria. In a glomerular disease biorepository cohort (n = 128), we measured time-of-biopsy albuminuria, proteinuria, and plasmin (ogen) uria for correlations with kidney outcomes. In cultured human podocytes, plasminogen treatment was associated with decreased focal adhesion marker expression with rescue by amiloride. Increased glomerular plasmin (ogen) was found in PAN rats and focal segmental glomerulosclerosis (FSGS) patients. PAN nephropathy was associated with increases in plasmin (ogen) uria and proteinuria. Amiloride was protective against PAN-induced glomerular injury, reducing CD36 scavenger receptor expression and oxidative stress. In patients, we found associations between plasmin (ogen) uria and edema status as well as eGFR. Our study demonstrates a role for plasmin (ogen)-induced podocyte injury in the PAN nephropathy model, with amiloride having podocyte-protective properties. In one of the largest glomerular disease cohorts to study plasminogen, we validated previous findings while suggesting a potentially novel relationship between plasmin (ogen) uria and estimated glomerular filtration rate (eGFR). Together, these findings suggest a role for plasmin (ogen) in mediating glomerular injury and as a viable targetable biomarker for podocyte-sparing treatments.
Collapse
Affiliation(s)
- Marc A. Egerman
- Division of Nephrology, Department of Medicine, Icahn School of Medicine at Mount Sinai
| | - Jenny S. Wong
- Division of Nephrology, Department of Medicine, Icahn School of Medicine at Mount Sinai
| | - Tian Runxia
- Katz Family Division of Nephrology and Hypertension, Department of Medicine, University of Miami Miller School of Medicine
| | - Gohar Mosoyan
- Division of Nephrology, Department of Medicine, Icahn School of Medicine at Mount Sinai
| | - Kinsuk Chauhan
- Division of Nephrology, Department of Medicine, Icahn School of Medicine at Mount Sinai
| | | | | | - Nicholas J. Wong
- Division of Nephrology, Department of Medicine, Icahn School of Medicine at Mount Sinai
| | - Emilia Bagiella
- Center for Biostatistics, Department of Population health Science and Policy, Icahn School of Medicine at Mount Sinai
| | - Fadi Salem
- Department of Pathology, Department of Medicine, Icahn School of Medicine at Mount Sinai
| | - Kristin Meliambro
- Division of Nephrology, Department of Medicine, Icahn School of Medicine at Mount Sinai
| | - Hong Li
- Department of Microbiology, Biochemistry and Molecular Genetics, Rutgers New Jersey Medical School
| | - Evren U. Azeloglu
- Division of Nephrology, Department of Medicine, Icahn School of Medicine at Mount Sinai
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai
| | - Steven G. Coca
- Division of Nephrology, Department of Medicine, Icahn School of Medicine at Mount Sinai
| | - Kirk N. Campbell
- Division of Nephrology, Department of Medicine, Icahn School of Medicine at Mount Sinai
| | - Leopoldo Raij
- Katz Family Division of Nephrology and Hypertension, Department of Medicine, University of Miami Miller School of Medicine
| |
Collapse
|
30
|
Yamada H, Shirata N, Makino S, Miyake T, Trejo JAO, Yamamoto-Nonaka K, Kikyo M, Empitu MA, Kadariswantiningsih IN, Kimura M, Ichimura K, Yokoi H, Mukoyama M, Hotta A, Nishimori K, Yanagita M, Asanuma K. MAGI-2 orchestrates the localization of backbone proteins in the slit diaphragm of podocytes. Kidney Int 2020; 99:382-395. [PMID: 33144214 DOI: 10.1016/j.kint.2020.09.027] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Revised: 08/22/2020] [Accepted: 09/10/2020] [Indexed: 01/19/2023]
Abstract
Podocytes are highly specialized cells within the glomerulus that are essential for ultrafiltration. The slit diaphragm between the foot processes of podocytes functions as a final filtration barrier to prevent serum protein leakage into urine. The slit-diaphragm consists mainly of Nephrin and Neph1, and localization of these backbone proteins is essential to maintaining the integrity of the glomerular filtration barrier. However, the mechanisms that regulate the localization of these backbone proteins have remained elusive. Here, we focused on the role of membrane-associated guanylate kinase inverted 2 (MAGI-2) in order to investigate mechanisms that orchestrate localization of slit-diaphragm backbone proteins. MAGI-2 downregulation coincided with a reduced expression of slit-diaphragm backbone proteins in human kidneys glomerular disease such as focal segmental glomerulosclerosis or IgA nephropathy. Podocyte-specific deficiency of MAGI-2 in mice abrogated localization of Nephrin and Neph1 independently of other scaffold proteins. Although a deficiency of zonula occuldens-1 downregulated the endogenous Neph1 expression, MAGI-2 recovered Neph1 expression at the cellular edge in cultured podocytes. Additionally, overexpression of MAGI-2 preserved Nephrin localization to intercellular junctions. Co-immunoprecipitation and pull-down assays also revealed the importance of the PDZ domains of MAGI-2 for the interaction between MAGI-2 and slit diaphragm backbone proteins in podocytes. Thus, localization and stabilization of Nephrin and Neph1 in intercellular junctions is regulated mainly via the PDZ domains of MAGI-2 together with other slit-diaphragm scaffold proteins. Hence, these findings may elucidate a mechanism by which the backbone proteins are maintained.
Collapse
Affiliation(s)
- Hiroyuki Yamada
- Department of Nephrology, Graduate School of Medicine, Chiba University, Chiba, Japan; Department of Nephrology, Graduate School of Medicine, Kyoto University, Kyoto, Japan; Medical Innovation Center, TMK Project, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Naritoshi Shirata
- Medical Innovation Center, TMK Project, Graduate School of Medicine, Kyoto University, Kyoto, Japan; Sohyaku, Innovative Research Division, Mitsubishi Tanabe Pharmaceutical Corporation, Saitama, Japan
| | - Shinichi Makino
- Department of Nephrology, Graduate School of Medicine, Chiba University, Chiba, Japan; Department of Nephrology, Graduate School of Medicine, Kyoto University, Kyoto, Japan; Medical Innovation Center, TMK Project, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Takafumi Miyake
- Department of Nephrology, Graduate School of Medicine, Kyoto University, Kyoto, Japan; Medical Innovation Center, TMK Project, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | | | - Kanae Yamamoto-Nonaka
- Department of Nephrology, Graduate School of Medicine, Kyoto University, Kyoto, Japan; Medical Innovation Center, TMK Project, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Mitsuhiro Kikyo
- Medical Innovation Center, TMK Project, Graduate School of Medicine, Kyoto University, Kyoto, Japan; Sohyaku, Innovative Research Division, Mitsubishi Tanabe Pharmaceutical Corporation, Saitama, Japan
| | - Maulana A Empitu
- Department of Nephrology, Graduate School of Medicine, Chiba University, Chiba, Japan
| | | | - Maiko Kimura
- Department of Nephrology, Graduate School of Medicine, Chiba University, Chiba, Japan
| | - Koichiro Ichimura
- Department of Anatomy and Life Structure, Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Hideki Yokoi
- Department of Nephrology, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Masashi Mukoyama
- Department of Nephrology, Kumamoto University Graduate School of Medical Sciences, Kumamoto, Japan
| | - Akitsu Hotta
- Department of Reprogramming Science, Center for iPS Cell Research and Application (CiRA), Kyoto University, Kyoto, Japan
| | - Katsuhiko Nishimori
- Department of Obesity and Inflammation Research, Fukushima Medical University, Fukushima, Japan
| | - Motoko Yanagita
- Department of Nephrology, Graduate School of Medicine, Kyoto University, Kyoto, Japan; Medical Innovation Center, TMK Project, Graduate School of Medicine, Kyoto University, Kyoto, Japan; Institute for the Advanced Study of Human Biology (ASHBi), Kyoto University, Kyoto, Japan
| | - Katsuhiko Asanuma
- Department of Nephrology, Graduate School of Medicine, Chiba University, Chiba, Japan; Medical Innovation Center, TMK Project, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
| |
Collapse
|
31
|
Griffiths NW, Del Bel LM, Wilk R, Brill JA. Cellular homeostasis in the Drosophila retina requires the lipid phosphatase Sac1. Mol Biol Cell 2020; 31:1183-1199. [PMID: 32186963 PMCID: PMC7353163 DOI: 10.1091/mbc.e20-02-0161] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The complex functions of cellular membranes, and thus overall cell physiology, depend on the distribution of crucial lipid species. Sac1 is an essential, conserved, ER-localized phosphatase whose substrate, phosphatidylinositol 4-phosphate (PI4P), coordinates secretory trafficking and plasma membrane function. PI4P from multiple pools is delivered to Sac1 by oxysterol-binding protein and related proteins in exchange for other lipids and sterols, which places Sac1 at the intersection of multiple lipid distribution pathways. However, much remains unknown about the roles of Sac1 in subcellular homeostasis and organismal development. Using a temperature-sensitive allele (Sac1ts), we show that Sac1 is required for structural integrity of the Drosophila retinal floor. The βps-integrin Myospheroid, which is necessary for basal cell adhesion, is mislocalized in Sac1ts retinas. In addition, the adhesion proteins Roughest and Kirre, which coordinate apical retinal cell patterning at an earlier stage, accumulate within Sac1ts retinal cells due to impaired endo-lysosomal degradation. Moreover, Sac1 is required for ER homeostasis in Drosophila retinal cells. Together, our data illustrate the importance of Sac1 in regulating multiple aspects of cellular homeostasis during tissue development.
Collapse
Affiliation(s)
- Nigel W Griffiths
- Cell Biology Program, The Hospital for Sick Children, Toronto, ON M5G 0A4, Canada.,Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Lauren M Del Bel
- Cell Biology Program, The Hospital for Sick Children, Toronto, ON M5G 0A4, Canada.,Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Ronit Wilk
- Cell Biology Program, The Hospital for Sick Children, Toronto, ON M5G 0A4, Canada
| | - Julie A Brill
- Cell Biology Program, The Hospital for Sick Children, Toronto, ON M5G 0A4, Canada.,Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada
| |
Collapse
|
32
|
Kawachi H, Fukusumi Y. New insight into podocyte slit diaphragm, a therapeutic target of proteinuria. Clin Exp Nephrol 2020; 24:193-204. [PMID: 32020343 PMCID: PMC7040068 DOI: 10.1007/s10157-020-01854-3] [Citation(s) in RCA: 59] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2019] [Accepted: 01/15/2020] [Indexed: 12/26/2022]
Abstract
Dysfunction of slit diaphragm, a cell–cell junction of glomerular podocytes, is involved in the development of proteinuria in several glomerular diseases. Slit diaphragm should be a target of a novel therapy for proteinuria. Nephrin, NEPH1, P-cadherin, FAT, and ephrin-B1 were reported to be extracellular components forming a molecular sieve of the slit diaphragm. Several cytoplasmic proteins such as ZO-1, podocin, CD2AP, MAGI proteins and Par-complex molecules were identified as scaffold proteins linking the slit diaphragm to the cytoskeleton. In this article, new insights into these molecules and the pathogenic roles of the dysfunction of these molecules were introduced. The slit diaphragm functions not only as a barrier but also as a signaling platform transfer the signal to the inside of the cell. For maintaining the slit diaphragm function properly, the phosphorylation level of nephrin is strictly regulated. The recent studies on the signaling pathway from nephrin, NEPH1, and ephrin-B1 were reviewed. Although the mechanism regulating the function of the slit diaphragm had remained unclear, recent studies revealed TRPC6 and angiotensin II-regulating mechanisms play a critical role in regulating the barrier function of the slit diaphragm. In this review, recent investigations on the regulation of the slit diaphragm function were reviewed, and a strategy for the establishment of a novel therapy for proteinuria was proposed.
Collapse
Affiliation(s)
- Hiroshi Kawachi
- Department of Cell Biology, Kidney Research Center, Niigata University Graduate School of Medical and Dental Sciences, 1-757 Asahimachi-dori, Chuo-ku, Niigata, 951-8510, Japan.
| | - Yoshiyasu Fukusumi
- Department of Cell Biology, Kidney Research Center, Niigata University Graduate School of Medical and Dental Sciences, 1-757 Asahimachi-dori, Chuo-ku, Niigata, 951-8510, Japan
| |
Collapse
|
33
|
Stavniichuk A, Savchuk O, Khan AH, Jankiewicz WK, Imig JD. A SORAFENIB INDUCED MODEL OF GLOMERULAR KIDNEY DISEASE. ACTA ACUST UNITED AC 2020; 81:25-31. [PMID: 33251532 DOI: 10.17721/1728_2748.2020.81.25-31] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Glomerular injury and proteinuria are important pathophysiological features of chronic kidney disease. In the present study, we provide data on a glomerular injury model that was developed using the cancer chemotherapy drug sorafenib. Sorafenib is a tyrosine kinase inhibitor that acts via the vascular endothelial growth factor (VEGF) signaling pathway and is widely used to treat a variety of cancers. On the other hand, sorafenib causes serious renal side effects in patients including the development of chronic kidney disease. The current study aimed to utilize the nephrotoxic property of sorafenib to develop a rat model for chronic kidney disease. We demonstrate that rats administered sorafenib for 8 weeks along with a high salt diet (8% NaCl enriched) develop hypertension (80mmHg higher systolic blood pressure), proteinuria (75% higher), and 4-fold higher glomerular injury compared to vehicle-treated normal control rat. Sorafenib induced glomerular injury was associated with decreased (20-80% lower) renal mRNA expression of key glomerular structural proteins such as nephrin, podocin, synaptopodin, and podoplanin compared to vehicle-treated normal control rat. Renal cortical endothelial-to-mesenchymal transition (EndoMT) was activated in the sorafenib induced glomerular injury model. In the sorafenib treated rats, the renal EndoMT was evident with 20% lower mRNA expression of an endothelial marker WT-1 and 2 to 3-fold higher expression of mesenchymal markers Col III, FSP-1, α-SMA, and vimentin. In conclusion, we developed a rat pre-clinical chronic kidney disease model that manifest glomerular injury. We further demonstrate that the glomerular injury in this model is associated with decreased renal mRNA expression of key glomerular structural proteins and an activated kidney EndoMT.
Collapse
Affiliation(s)
| | - O Savchuk
- Taras Shevchenko National University, Kyiv, Ukraine
| | | | | | - John D Imig
- The Medical College of Wisconsin, Milwaukee, WI, USA
| |
Collapse
|
34
|
Powell DR, Doree DD, DaCosta CM, Platt KA, Hansen GM, van Sligtenhorst I, Ding ZM, Revelli JP, Brommage R. Obesity of G2e3 Knockout Mice Suggests That Obesity-Associated Variants Near Human G2E3 Decrease G2E3 Activity. Diabetes Metab Syndr Obes 2020; 13:2641-2652. [PMID: 32801815 PMCID: PMC7394505 DOI: 10.2147/dmso.s259546] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Accepted: 07/02/2020] [Indexed: 12/12/2022] Open
Abstract
PURPOSE In humans, single nucleotide polymorphisms (SNPs) near the adjacent protein kinase D1 (PRKD1) and G2/M-phase-specific E3 ubiquitin protein ligase (G2E3) genes on chromosome 14 are associated with obesity. To date, no published evidence links inactivation of either gene to changes in body fat. These two genes are also adjacent on mouse chromosome 12. Because obesity genes are highly conserved between humans and mice, we analyzed body fat in adult G2e3 and Prkd1 knockout (KO) mice to determine whether inactivating either gene leads to obesity in mice and, by inference, probably in humans. METHODS The G2e3 and Prkd1 KO lines were generated by gene trapping and by homologous recombination methodologies, respectively. Body fat was measured by DEXA in adult mice fed chow from weaning and by QMR in a separate cohort of mice fed high-fat diet (HFD) from weaning. Glucose homeostasis was evaluated with oral glucose tolerance tests (OGTTs) performed on adult mice fed HFD from weaning. RESULTS Body fat was increased in multiple cohorts of G2e3 KO mice relative to their wild-type (WT) littermates. When data from all G2e3 KO (n=32) and WT (n=31) mice were compared, KO mice showed increases of 11% in body weight (P<0.01), 65% in body fat (P<0.001), 48% in % body fat (P<0.001), and an insignificant 3% decrease in lean body mass. G2e3 KO mice were also glucose intolerant during an OGTT (P<0.05). In contrast, Prkd1 KO and WT mice had comparable body fat levels and glucose tolerance. CONCLUSION Significant obesity and glucose intolerance were observed in G2e3, but not Prkd1, KO mice. The conservation of obesity genes between mice and humans strongly suggests that the obesity-associated SNPs located near the human G2E3 and PRKD1 genes are linked to variants that decrease the amount of functional human G2E3.
Collapse
Affiliation(s)
- David R Powell
- Lexicon Pharmaceuticals Inc, The Woodlands, TX, 77381, USA
- Correspondence: David R Powell Lexicon Pharmaceuticals Inc., 8800 Technology Forest Place, The Woodlands, TX77381, USATel +1 281 863 3060Fax +1 281 863 8115 Email
| | - Deon D Doree
- Lexicon Pharmaceuticals Inc, The Woodlands, TX, 77381, USA
| | | | | | - Gwenn M Hansen
- Lexicon Pharmaceuticals Inc, The Woodlands, TX, 77381, USA
| | | | - Zhi-Ming Ding
- Lexicon Pharmaceuticals Inc, The Woodlands, TX, 77381, USA
| | | | | |
Collapse
|
35
|
Takamura S, Fukusumi Y, Zhang Y, Narita I, Kawachi H. Partitioning-Defective-6-Ephrin-B1 Interaction Is Regulated by Nephrin-Mediated Signal and Is Crucial in Maintaining Slit Diaphragm of Podocyte. THE AMERICAN JOURNAL OF PATHOLOGY 2019; 190:333-346. [PMID: 31837290 DOI: 10.1016/j.ajpath.2019.10.015] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2019] [Revised: 09/04/2019] [Accepted: 10/18/2019] [Indexed: 01/15/2023]
Abstract
Ephrin-B1 plays a critical role at slit diaphragm. Partitioning-defective (Par)-6 is down-regulated in podocyte of ephrin-B1 knockout mouse, suggesting that Par-6 is associated with ephrin-B1. Par polarity complex, consisting of Par-6, Par-3, and atypical protein kinase C, is essential for tight junction formation. In this study, the expression of Par-6 was analyzed in the normal and nephrotic syndrome model rats, and the molecular association of Par-6, Par-3, ephrin-B1, and nephrin was assessed with the human embryonic kidney 293 cell expression system. Par-6 was concentrated at slit diaphragm. Par 6 interacted with ephrin-B1 but not with nephrin, and Par-3 interacted with nephrin but not with ephrin-B1. The complexes of Par-6-ephrin-B1 and Par-3-nephrin were linked via extracellular sites of ephrin-B1 and nephrin. The Par-6-ephrin-B1 complex was delinked from the Par-3-nephrin complex, and Par-6 and ephrin-B1 were clearly down-regulated already at early phase of nephrotic model. The alteration of Par-6/ephrin-B1 advanced that of Par-3/nephrin. Stimulation to nephrin phosphorylated not only nephrin but also ephrin-B1, and consequently inhibited the interaction between ephrin-B1 and Par-6. Par-6 appeared at presumptive podocyte of early developmental stage and moved to basal area at capillary loop stage to participate in slit diaphragm formation at the final stage. Par-6-ephrin-B1 interaction is crucial for formation and maintenance of slit diaphragm of podocyte.
Collapse
Affiliation(s)
- Sayuri Takamura
- Department of Cell Biology, Kidney Research Center, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan; Division of Clinical Nephrology and Rheumatology, Kidney Research Center, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Yoshiyasu Fukusumi
- Department of Cell Biology, Kidney Research Center, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Ying Zhang
- Department of Cell Biology, Kidney Research Center, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Ichiei Narita
- Division of Clinical Nephrology and Rheumatology, Kidney Research Center, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Hiroshi Kawachi
- Department of Cell Biology, Kidney Research Center, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan.
| |
Collapse
|
36
|
Solanki AK, Widmeier E, Arif E, Sharma S, Daga A, Srivastava P, Kwon SH, Hugo H, Nakayama M, Mann N, Majmundar AJ, Tan W, Gee HY, Sadowski CE, Rinat C, Becker-Cohen R, Bergmann C, Rosen S, Somers M, Shril S, Huber TB, Mane S, Hildebrandt F, Nihalani D. Mutations in KIRREL1, a slit diaphragm component, cause steroid-resistant nephrotic syndrome. Kidney Int 2019; 96:883-889. [PMID: 31472902 PMCID: PMC6756928 DOI: 10.1016/j.kint.2019.06.016] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Revised: 06/11/2019] [Accepted: 06/14/2019] [Indexed: 12/22/2022]
Abstract
Steroid-resistant nephrotic syndrome is a frequent cause of chronic kidney disease almost inevitably progressing to end-stage renal disease. More than 58 monogenic causes of SRNS have been discovered and majority of known steroid-resistant nephrotic syndrome causing genes are predominantly expressed in glomerular podocytes, placing them at the center of disease pathogenesis. Herein, we describe two unrelated families with steroid-resistant nephrotic syndrome with homozygous mutations in the KIRREL1 gene. One mutation showed high frequency in the European population (minor allele frequency 0.0011) and this patient achieved complete remission following treatment, but later progressed to chronic kidney disease. We found that mutant KIRREL1 proteins failed to localize to the podocyte cell membrane, indicating defective trafficking and impaired podocytes function. Thus, the KIRREL1 gene product has an important role in modulating the integrity of the slit diaphragm and maintaining glomerular filtration function.
Collapse
Affiliation(s)
- Ashish K Solanki
- Department of Medicine, Nephrology Division, Medical University of South Carolina, Charleston, South Carolina, USA
| | - Eugen Widmeier
- Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA; Department of Medicine IV, Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Ehtesham Arif
- Department of Medicine, Nephrology Division, Medical University of South Carolina, Charleston, South Carolina, USA
| | - Shailza Sharma
- Department of Medicine, Nephrology Division, Medical University of South Carolina, Charleston, South Carolina, USA
| | - Ankana Daga
- Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Pankaj Srivastava
- Department of Medicine, Nephrology Division, Medical University of South Carolina, Charleston, South Carolina, USA
| | - Sang-Ho Kwon
- Department of Cellular Biology and Anatomy, Augusta University, Augusta, Georgia, USA
| | - Hannah Hugo
- Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Makiko Nakayama
- Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Nina Mann
- Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Amar J Majmundar
- Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Wei Tan
- Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Heon Yung Gee
- Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA; Department of Pharmacology, Brain Korea 21 Program for Leading Universities & Students (PLUS) Project for Medical Sciences, Yonsei University College of Medicine, Seoul, Korea
| | - Caroline E Sadowski
- Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Choni Rinat
- Division of Pediatric Nephrology, Shaare Zedek Medical Center, The Hadassah-Hebrew University School of Medicine, Jerusalem, Israel
| | - Rachel Becker-Cohen
- Division of Pediatric Nephrology, Shaare Zedek Medical Center, The Hadassah-Hebrew University School of Medicine, Jerusalem, Israel
| | - Carsten Bergmann
- Department of Medicine IV, Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Seymour Rosen
- Department of Pathology, Beth Israel Deaconess Medical Center, Boston, Massachusetts, USA
| | - Michael Somers
- Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Shirlee Shril
- Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Tobias B Huber
- Department of Medicine IV, Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany; III Department of Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany; Biological Signalling Studies (BIOSS) Center for Biological Signaling Studies, Albert-Ludwigs-University, Freiburg, Germany
| | - Shrikant Mane
- Department of Genetics, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Friedhelm Hildebrandt
- Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA.
| | - Deepak Nihalani
- Department of Medicine, Nephrology Division, Medical University of South Carolina, Charleston, South Carolina, USA.
| |
Collapse
|
37
|
Ohta Y, Kasahara M, O'Connor TD, Flajnik MF. Inferring the "Primordial Immune Complex": Origins of MHC Class I and Antigen Receptors Revealed by Comparative Genomics. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2019; 203:1882-1896. [PMID: 31492741 PMCID: PMC6761025 DOI: 10.4049/jimmunol.1900597] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2019] [Accepted: 08/02/2019] [Indexed: 02/07/2023]
Abstract
Comparative analyses suggest that the MHC was derived from a prevertebrate "primordial immune complex" (PIC). PIC duplicated twice in the well-studied two rounds of genome-wide duplications (2R) early in vertebrate evolution, generating four MHC paralogous regions (predominantly on human chromosomes [chr] 1, 6, 9, 19). Examining chiefly the amphibian Xenopus laevis, but also other vertebrates, we identified their MHC paralogues and mapped MHC class I, AgR, and "framework" genes. Most class I genes mapped to MHC paralogues, but a cluster of Xenopus MHC class Ib genes (xnc), which previously was mapped outside of the MHC paralogues, was surrounded by genes syntenic to mammalian CD1 genes, a region previously proposed as an MHC paralogue on human chr 1. Thus, this gene block is instead the result of a translocation that we call the translocated part of the MHC paralogous region (MHCtrans) Analyses of Xenopus class I genes, as well as MHCtrans, suggest that class I arose at 1R on the chr 6/19 ancestor. Of great interest are nonrearranging AgR-like genes mapping to three MHC paralogues; thus, PIC clearly contained several AgR precursor loci, predating MHC class I/II. However, all rearranging AgR genes were found on paralogues derived from the chr 19 precursor, suggesting that invasion of a variable (V) exon by the RAG transposon occurred after 2R. We propose models for the evolutionary history of MHC/TCR/Ig and speculate on the dichotomy between the jawless (lamprey and hagfish) and jawed vertebrate adaptive immune systems, as we found genes related to variable lymphocyte receptors also map to MHC paralogues.
Collapse
Affiliation(s)
- Yuko Ohta
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, MD 21201
| | - Masanori Kasahara
- Department of Pathology, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo 060-8638, Japan
| | - Timothy D O'Connor
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, MD, 21201
- Program in Personalized and Genomic Medicine, University of Maryland School of Medicine, Baltimore, MD, 21201
- Marlene and Stewart Greenebaum Comprehensive Cancer Center, University of Maryland School of Medicine, Baltimore, MD, 21201; and
- Department of Medicine, University of Maryland School of Medicine, Baltimore, MD 21201
| | - Martin F Flajnik
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, MD 21201;
| |
Collapse
|
38
|
Dlugos CP, Picciotto C, Lepa C, Krakow M, Stöber A, Eddy ML, Weide T, Jeibmann A, P Krahn M, Van Marck V, Klingauf J, Ricker A, Wedlich-Söldner R, Pavenstädt H, Klämbt C, George B. Nephrin Signaling Results in Integrin β1 Activation. J Am Soc Nephrol 2019; 30:1006-1019. [PMID: 31097607 DOI: 10.1681/asn.2018040362] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2018] [Accepted: 03/18/2019] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND Patients with certain mutations in the gene encoding the slit diaphragm protein Nephrin fail to develop functional slit diaphragms and display severe proteinuria. Many adult-onset glomerulopathies also feature alterations in Nephrin expression and function. Nephrin signals from the podocyte slit diaphragm to the Actin cytoskeleton by recruiting proteins that can interact with C3G, a guanine nucleotide exchange factor of the small GTPase Rap1. Because Rap activity affects formation of focal adhesions, we hypothesized that Nephrin transmits signals to the Integrin receptor complex, which mediates podocyte adhesion to the extracellular matrix. METHODS To investigate Nephrin's role in transmitting signals to the Integrin receptor complex, we conducted genetic studies in Drosophila nephrocytes and validated findings from Drosophila in a cultured human podocyte model. RESULTS Drosophila nephrocytes form a slit diaphragm-like filtration barrier and express the Nephrin ortholog Sticks and stones (Sns). A genetic screen identified c3g as necessary for nephrocyte function. In vivo, nephrocyte-specific gene silencing of sns or c3g compromised nephrocyte filtration and caused nephrocyte diaphragm defects. Nephrocytes with impaired Sns or C3G expression displayed an altered localization of Integrin and the Integrin-associated protein Talin. Furthermore, gene silencing of c3g partly rescued nephrocyte diaphragm defects of an sns overexpression phenotype, pointing to genetic interaction of sns and c3g in nephrocytes. We also found that activated Nephrin recruited phosphorylated C3G and resulted in activation of Integrin β1 in cultured podocytes. CONCLUSIONS Our findings suggest that Nephrin can mediate a signaling pathway that results in activation of Integrin β1 at focal adhesions, which may affect podocyte attachment to the extracellular matrix.
Collapse
Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | | | | | | | - Christian Klämbt
- Neurobiology, Westfälische-Wilhelms University Münster, Münster, Germany
| | | |
Collapse
|
39
|
Brommage R, Powell DR, Vogel P. Predicting human disease mutations and identifying drug targets from mouse gene knockout phenotyping campaigns. Dis Model Mech 2019; 12:dmm038224. [PMID: 31064765 PMCID: PMC6550044 DOI: 10.1242/dmm.038224] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Two large-scale mouse gene knockout phenotyping campaigns have provided extensive data on the functions of thousands of mammalian genes. The ongoing International Mouse Phenotyping Consortium (IMPC), with the goal of examining all ∼20,000 mouse genes, has examined 5115 genes since 2011, and phenotypic data from several analyses are available on the IMPC website (www.mousephenotype.org). Mutant mice having at least one human genetic disease-associated phenotype are available for 185 IMPC genes. Lexicon Pharmaceuticals' Genome5000™ campaign performed similar analyses between 2000 and the end of 2008 focusing on the druggable genome, including enzymes, receptors, transporters, channels and secreted proteins. Mutants (4654 genes, with 3762 viable adult homozygous lines) with therapeutically interesting phenotypes were studied extensively. Importantly, phenotypes for 29 Lexicon mouse gene knockouts were published prior to observations of similar phenotypes resulting from homologous mutations in human genetic disorders. Knockout mouse phenotypes for an additional 30 genes mimicked previously published human genetic disorders. Several of these models have helped develop effective treatments for human diseases. For example, studying Tph1 knockout mice (lacking peripheral serotonin) aided the development of telotristat ethyl, an approved treatment for carcinoid syndrome. Sglt1 (also known as Slc5a1) and Sglt2 (also known as Slc5a2) knockout mice were employed to develop sotagliflozin, a dual SGLT1/SGLT2 inhibitor having success in clinical trials for diabetes. Clinical trials evaluating inhibitors of AAK1 (neuropathic pain) and SGLT1 (diabetes) are underway. The research community can take advantage of these unbiased analyses of gene function in mice, including the minimally studied 'ignorome' genes.
Collapse
Affiliation(s)
- Robert Brommage
- Department of Metabolism Research, Lexicon Pharmaceuticals, 8800 Technology Forest Place, The Woodlands, TX 77381, USA
| | - David R Powell
- Department of Metabolism Research, Lexicon Pharmaceuticals, 8800 Technology Forest Place, The Woodlands, TX 77381, USA
| | - Peter Vogel
- St. Jude Children's Research Hospital, Pathology, MS 250, Room C5036A, 262 Danny Thomas Place, Memphis, TN 38105, USA
| |
Collapse
|
40
|
Odenthal J, Brinkkoetter PT. Drosophila melanogaster and its nephrocytes: A versatile model for glomerular research. Methods Cell Biol 2019; 154:217-240. [PMID: 31493819 DOI: 10.1016/bs.mcb.2019.03.011] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
Abstract
Glomerular disorders are a predominant cause of chronic kidney diseases and end-stage renal failure. Especially podocytes, epithelial cells which represent the outermost part of the filtration barrier, are affected by disease and experience a gradual loss of function. Despite recent advances in identifying potential pathways underlying podocyte injury, treatment remains challenging. It is therefore desirable to employ suitable model organisms in order to study glomerular disease and elucidate affected pathways. Due to its diverse ways of genetic manipulation and high genomic conservation, Drosophila melanogaster is a powerful model organism for biomedical research. The fly was recently used to assess podocytopathies by exploiting the nephrocyte system. Nephrocytes are spherical cells within the body cavity of the fly responsible for detoxification and clearance of unwanted substances. More importantly, they share many characteristics with mammalian podocytes. Here, we summarize how to use Drosophila as a model organism for podocyte research. We discuss examples of techniques that can be used to genetically manipulate nephrocytes and provide protocols for nephrocyte isolation and for morphological as well as functional analysis.
Collapse
Affiliation(s)
- Johanna Odenthal
- Department II of Internal Medicine and Center for Molecular Medicine Cologne, University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany; CECAD, University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany
| | - Paul Thomas Brinkkoetter
- Department II of Internal Medicine and Center for Molecular Medicine Cologne, University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany; CECAD, University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany.
| |
Collapse
|
41
|
Tanigawa S, Islam M, Sharmin S, Naganuma H, Yoshimura Y, Haque F, Era T, Nakazato H, Nakanishi K, Sakuma T, Yamamoto T, Kurihara H, Taguchi A, Nishinakamura R. Organoids from Nephrotic Disease-Derived iPSCs Identify Impaired NEPHRIN Localization and Slit Diaphragm Formation in Kidney Podocytes. Stem Cell Reports 2018; 11:727-740. [PMID: 30174315 PMCID: PMC6135868 DOI: 10.1016/j.stemcr.2018.08.003] [Citation(s) in RCA: 95] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Revised: 08/02/2018] [Accepted: 08/03/2018] [Indexed: 12/19/2022] Open
Abstract
Mutations in the NPHS1 gene, which encodes NEPHRIN, cause congenital nephrotic syndrome, resulting from impaired slit diaphragm (SD) formation in glomerular podocytes. However, methods for SD reconstitution have been unavailable, thereby limiting studies in the field. In the present study, we established human induced pluripotent stem cells (iPSCs) from a patient with an NPHS1 missense mutation, and reproduced the SD formation process using iPSC-derived kidney organoids. The mutant NEPHRIN failed to become localized on the cell surface for pre-SD domain formation in the induced podocytes. Upon transplantation, the mutant podocytes developed foot processes, but exhibited impaired SD formation. Genetic correction of the single amino acid mutation restored NEPHRIN localization and phosphorylation, colocalization of other SD-associated proteins, and SD formation. Thus, these kidney organoids from patient-derived iPSCs identified SD abnormalities in the podocytes at the initial phase of congenital nephrotic disease. iPSCs are established from a patient with a missense NPHS1 mutation The induced podocytes exhibit impaired NEPHRIN localization The slit diaphragm is lacking in the mutant podocytes Genetic correction of the point mutation restores the phenotypes
Collapse
Affiliation(s)
- Shunsuke Tanigawa
- Department of Kidney Development, Institute of Molecular Embryology and Genetics, Kumamoto University, Kumamoto 860-0811, Japan
| | - Mazharul Islam
- Department of Kidney Development, Institute of Molecular Embryology and Genetics, Kumamoto University, Kumamoto 860-0811, Japan
| | - Sazia Sharmin
- Department of Kidney Development, Institute of Molecular Embryology and Genetics, Kumamoto University, Kumamoto 860-0811, Japan
| | - Hidekazu Naganuma
- Department of Kidney Development, Institute of Molecular Embryology and Genetics, Kumamoto University, Kumamoto 860-0811, Japan; Department of Urology, Graduate School of Medical Sciences, Kyushu University, Fukuoka 812-8582, Japan
| | - Yasuhiro Yoshimura
- Department of Kidney Development, Institute of Molecular Embryology and Genetics, Kumamoto University, Kumamoto 860-0811, Japan
| | - Fahim Haque
- Department of Kidney Development, Institute of Molecular Embryology and Genetics, Kumamoto University, Kumamoto 860-0811, Japan
| | - Takumi Era
- Department of Cell Modulation, Institute of Molecular Embryology and Genetics, Kumamoto University, Kumamoto 860-0811, Japan
| | - Hitoshi Nakazato
- Department of Pediatrics, Faculty of Life Sciences, Kumamoto University, Kumamoto 860-8556, Japan
| | - Koichi Nakanishi
- Department of Child Health and Welfare (Pediatrics), Graduate School of Medicine, University of the Ryukyus, Okinawa 903-0215, Japan
| | - Tetsushi Sakuma
- Department of Mathematical and Life Sciences, Graduate School of Science, Hiroshima University, Hiroshima 739-8526, Japan
| | - Takashi Yamamoto
- Department of Mathematical and Life Sciences, Graduate School of Science, Hiroshima University, Hiroshima 739-8526, Japan
| | - Hidetake Kurihara
- Department of Anatomy and Life Structure, Juntendo University School of Medicine, Tokyo 113-8421, Japan
| | - Atsuhiro Taguchi
- Department of Kidney Development, Institute of Molecular Embryology and Genetics, Kumamoto University, Kumamoto 860-0811, Japan
| | - Ryuichi Nishinakamura
- Department of Kidney Development, Institute of Molecular Embryology and Genetics, Kumamoto University, Kumamoto 860-0811, Japan.
| |
Collapse
|
42
|
Empitu MA, Kadariswantiningsih IN, Aizawa M, Asanuma K. MAGI-2 and scaffold proteins in glomerulopathy. Am J Physiol Renal Physiol 2018; 315:F1336-F1344. [PMID: 30110567 DOI: 10.1152/ajprenal.00292.2018] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
In many cells and tissues, including the glomerular filtration barrier, scaffold proteins are critical in optimizing signal transduction by enhancing structural stability and functionality of their ligands. Recently, mutations in scaffold protein membrane-associated guanylate kinase inverted 2 (MAGI-2) encoding gene were identified among the etiology of steroid-resistant nephrotic syndrome. MAGI-2 interacts with core proteins of multiple pathways, such as transforming growth factor-β signaling, planar cell polarity pathway, and Wnt/β-catenin signaling in podocyte and slit diaphragm. Through the interaction with its ligand, MAGI-2 modulates the regulation of apoptosis, cytoskeletal reorganization, and glomerular development. This review aims to summarize recent findings on the role of MAGI-2 and some other scaffold proteins, such as nephrin and synaptopodin, in the underlying mechanisms of glomerulopathy.
Collapse
Affiliation(s)
- Maulana A Empitu
- Department of Nephrology, Graduate School of Medicine, Chiba University , Chiba , Japan.,Department of Pharmacology and Therapeutics, Faculty of Medicine, Universitas Airlangga , Surabaya , Indonesia
| | - Ika N Kadariswantiningsih
- Department of Nephrology, Graduate School of Medicine, Chiba University , Chiba , Japan.,Department of Medical Microbiology, Faculty of Medicine, Universitas Airlangga , Surabaya , Indonesia
| | - Masashi Aizawa
- Department of Nephrology, Graduate School of Medicine, Chiba University , Chiba , Japan
| | - Katsuhiko Asanuma
- Department of Nephrology, Graduate School of Medicine, Chiba University , Chiba , Japan
| |
Collapse
|
43
|
Machado MCR, Valer FB, Couto-Lima CA, Ramos RGP. Transcriptional cross-regulation of Irre Cell Recognition Module (IRM) members in the Drosophila pupal retina. Mech Dev 2018; 154:193-202. [PMID: 30030087 DOI: 10.1016/j.mod.2018.07.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2018] [Revised: 06/26/2018] [Accepted: 07/16/2018] [Indexed: 12/13/2022]
Abstract
Cell adhesion molecules play a central role in morphogenesis, as they mediate the complex range of interactions between different cell types that result in their arrangement in multicellular organs and tissues. How their coordinated dynamic expression in space and time - an essential requirement for their function - is regulated at the genomic and transcriptional levels constitutes an important, albeit still little understood question. The Irre Cell Recognition Module (IRM) is a highly conserved phylogenetically group of structurally related single pass transmembrane glycoproteins belonging to the immunoglobulin superfamily that in Drosophila melanogaster are encoded by the genes roughest (rst), kin-of-irre (kirre), sticks-and-stones (sns) and hibris (hbs). Their cooperative and often partly redundant action are crucial to major developmental processes such axonal pathfinding, myoblast fusion and patterning of the pupal retina. In this latter system rst and kirre display a tightly regulated complementary transcriptional pattern so that lowering rst mRNA levels leads to a concomitant increase in kirre mRNA concentration. Here we investigated whether other IRM components are similarly co-regulated and the extent changes in their mRNA levels affect each other as well as their collective function in retinal patterning. Our results demonstrate that silencing any of the four IRM genes in 24% APF retinae changes the levels all other group members although only kirre and hbs mRNA levels are increased. Furthermore, expression, in a rst null background, of truncated versions of rst cDNA in which the portion encoding the intracellular domain has been partially or completely removed not only can still induce changes in mRNA levels of other IRM members but also result in Kirre mislocalization. Taken together, our data point to the presence of a highly precise and fine-tuned control mechanism coordinating IRM expression that may be crucial to the functional redundancy shown by its components during the patterning of the pupal retina.
Collapse
Affiliation(s)
- Maiaro Cabral Rosa Machado
- Department of Cellular and Molecular Biology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
| | - Felipe Berti Valer
- Department of Cellular and Molecular Biology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
| | - Carlos Antonio Couto-Lima
- Department of Cellular and Molecular Biology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
| | | |
Collapse
|
44
|
Hagmann H, Brinkkoetter PT. Experimental Models to Study Podocyte Biology: Stock-Taking the Toolbox of Glomerular Research. Front Pediatr 2018; 6:193. [PMID: 30057894 PMCID: PMC6053518 DOI: 10.3389/fped.2018.00193] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/14/2018] [Accepted: 06/11/2018] [Indexed: 01/17/2023] Open
Abstract
Diseases affecting the glomeruli of the kidney, the renal filtration units, are a leading cause of chronic kidney disease and end-stage renal failure. Despite recent advances in the understanding of glomerular biology, treatment of these disorders has remained extraordinarily challenging in many cases. The use of experimental models has proven invaluable to study renal, and in particular, glomerular biology and disease. Over the past 15 years, studies identified different and very distinct pathogenic mechanisms that result in damage, loss of glomerular visceral epithelial cells (podocytes) and progressive renal disease. However, animal studies and, in particular, mouse studies are often protracted and cumbersome due to the long reproductive cycle and high keeping costs. Transgenic and heterologous expression models have been speeded-up by novel gene editing techniques, yet they still take months. In addition, given the complex cellular biology of the filtration barrier, certain questions may not be directly addressed using mouse models due to the limited accessibility of podocytes for analysis and imaging. In this review, we will describe alternative models to study podocyte biology experimentally. We specifically discuss current podocyte cell culture models, their role in experimental strategies to analyze pathophysiologic mechanisms as well as limitations with regard to transferability of results. We introduce current models in Caenorhabditis elegans, Drosophila melanogaster, and Danio rerio that allow for analysis of protein interactions, and principle signaling pathways in functional biological structures, and enable high-throughput transgenic expression or compound screens in multicellular organisms.
Collapse
Affiliation(s)
| | - Paul T. Brinkkoetter
- Department II of Internal Medicine, Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany
| |
Collapse
|
45
|
Drosophila pericardial nephrocyte ultrastructure changes during ageing. Mech Ageing Dev 2018; 173:9-20. [DOI: 10.1016/j.mad.2018.04.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2018] [Revised: 04/17/2018] [Accepted: 04/23/2018] [Indexed: 10/17/2022]
|
46
|
Del Bel LM, Griffiths N, Wilk R, Wei HC, Blagoveshchenskaya A, Burgess J, Polevoy G, Price JV, Mayinger P, Brill JA. The phosphoinositide phosphatase Sac1 regulates cell shape and microtubule stability in the developing Drosophila eye. Development 2018; 145:dev.151571. [PMID: 29752385 DOI: 10.1242/dev.151571] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2017] [Accepted: 04/30/2018] [Indexed: 12/15/2022]
Abstract
Epithelial patterning in the developing Drosophila melanogaster eye requires the Neph1 homolog Roughest (Rst), an immunoglobulin family cell surface adhesion molecule expressed in interommatidial cells (IOCs). Here, using a novel temperature-sensitive (ts) allele, we show that the phosphoinositide phosphatase Sac1 is also required for IOC patterning. Sac1ts mutants have rough eyes and retinal patterning defects that resemble rst mutants. Sac1ts retinas exhibit elevated levels of phosphatidylinositol 4-phosphate (PI4P), consistent with the role of Sac1 as a PI4P phosphatase. Indeed, genetic rescue and interaction experiments reveal that restriction of PI4P levels by Sac1 is crucial for normal eye development. Rst is delivered to the cell surface in Sac1ts mutants. However, Sac1ts mutant IOCs exhibit severe defects in microtubule organization, associated with accumulation of Rst and the exocyst subunit Sec8 in enlarged intracellular vesicles upon cold fixation ex vivo Together, our data reveal a novel requirement for Sac1 in promoting microtubule stability and suggest that Rst trafficking occurs in a microtubule- and exocyst-dependent manner.
Collapse
Affiliation(s)
- Lauren M Del Bel
- Cell Biology Program, The Hospital for Sick Children, PGCRL Building, 686 Bay Street, Toronto, Ontario, M5G 0A4, Canada.,Department of Molecular Genetics, University of Toronto, 1 King's College Circle, Toronto, Ontario, M5S 1A8, Canada
| | - Nigel Griffiths
- Cell Biology Program, The Hospital for Sick Children, PGCRL Building, 686 Bay Street, Toronto, Ontario, M5G 0A4, Canada.,Department of Molecular Genetics, University of Toronto, 1 King's College Circle, Toronto, Ontario, M5S 1A8, Canada
| | - Ronit Wilk
- Cell Biology Program, The Hospital for Sick Children, PGCRL Building, 686 Bay Street, Toronto, Ontario, M5G 0A4, Canada
| | - Ho-Chun Wei
- Cell Biology Program, The Hospital for Sick Children, PGCRL Building, 686 Bay Street, Toronto, Ontario, M5G 0A4, Canada.,Department of Molecular Biology and Biochemistry, Simon Fraser University, South Sciences Building Room 8166, 8888 University Drive, Burnaby, British Columbia, V5A 1S6, Canada
| | - Anastasia Blagoveshchenskaya
- Division of Nephrology & Hypertension, Oregon Health & Science University, 3181 S.W. Sam Jackson Park Rd., Portland, Oregon 97239-3098, USA
| | - Jason Burgess
- Cell Biology Program, The Hospital for Sick Children, PGCRL Building, 686 Bay Street, Toronto, Ontario, M5G 0A4, Canada.,Department of Molecular Genetics, University of Toronto, 1 King's College Circle, Toronto, Ontario, M5S 1A8, Canada
| | - Gordon Polevoy
- Cell Biology Program, The Hospital for Sick Children, PGCRL Building, 686 Bay Street, Toronto, Ontario, M5G 0A4, Canada
| | - James V Price
- Department of Molecular Biology and Biochemistry, Simon Fraser University, South Sciences Building Room 8166, 8888 University Drive, Burnaby, British Columbia, V5A 1S6, Canada
| | - Peter Mayinger
- Division of Nephrology & Hypertension, Oregon Health & Science University, 3181 S.W. Sam Jackson Park Rd., Portland, Oregon 97239-3098, USA
| | - Julie A Brill
- Cell Biology Program, The Hospital for Sick Children, PGCRL Building, 686 Bay Street, Toronto, Ontario, M5G 0A4, Canada .,Department of Molecular Genetics, University of Toronto, 1 King's College Circle, Toronto, Ontario, M5S 1A8, Canada
| |
Collapse
|
47
|
The long journey through renal filtration: new pieces in the puzzle of slit diaphragm architecture. Curr Opin Nephrol Hypertens 2018; 26:148-153. [PMID: 28212178 DOI: 10.1097/mnh.0000000000000322] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
PURPOSE OF REVIEW The podocyte slit diaphragm is probably the least understood component of the kidney filtration barrier. In this review, we aim to integrate the most recent findings on the molecular make-up and structural architecture of this specialized cell-cell junction into a current concept of glomerular filtration. RECENT FINDINGS Analysis of cryopreserved mammalian tissue revealed a bipartite composition of the slit diaphragm. Single NEPH1 molecules span the lower part of the slit close to the glomerular basement membrane whereas NEPHRIN molecules are positioned in the apical part toward Bowman's space. This molecular arrangement could lead to heterogeneous ellipsoidal and circular pores, which are mainly located in the central region of the slit diaphragm. SUMMARY Despite having been first identified in the 1970s, the slit diaphragm's structural architecture has not been fully elucidated to date and remains an area of intense research and scientific debate. The slit diaphragm has been initially described as a rigid 'zipper-like' structure in which periodic, rod-like units extend from a podocyte foot processes to a linear central bar, giving rise to homogeneous 4 × 14 nm pores. Several recent findings have challenged these long-held beliefs and instead pointed to an unanticipated complexity of slit diaphragm structure. High-resolution ultrastructural analysis found evidence that the slit diaphragm is a dynamic and adjustable cell-cell junction that forms a nonclogging barrier within the renal filtration system.
Collapse
|
48
|
Muraleedharan S, Sam A, Skaer H, Inamdar MS. Networks that link cytoskeletal regulators and diaphragm proteins underpin filtration function in Drosophila nephrocytes. Exp Cell Res 2018; 364:234-242. [PMID: 29458174 PMCID: PMC5883325 DOI: 10.1016/j.yexcr.2018.02.015] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2017] [Revised: 02/06/2018] [Accepted: 02/15/2018] [Indexed: 11/25/2022]
Abstract
Insect nephrocytes provide a valuable model for kidney disease, as they are structurally and functionally homologous to mammalian kidney podocytes. They possess an exceptional macromolecular assembly, the nephrocyte diaphragm (ND), which serves as a filtration barrier and helps maintain tissue homeostasis by filtering out wastes and toxic products. However, the elements that maintain nephrocyte architecture and the ND are not understood. We show that Drosophila nephrocytes have a unique cytoplasmic cluster of F-actin, which is maintained by the microtubule cytoskeleton and Rho-GTPases. A balance of Rac1 and Cdc42 activity as well as proper microtubule organization and endoplasmic reticulum structure, are required to position the actin cluster. Further, ND proteins Sns and Duf also localize to this cluster and regulate organization of the actin and microtubule cytoskeleton. Perturbation of any of these inter-dependent components impairs nephrocyte ultrafiltration. Thus cytoskeletal components, Rho-GTPases and ND proteins work in concert to maintain the specialized nephrocyte architecture and function. Drosophila nephrocytes have a unique cytoplasmic cluster of F-actin. Microtubules, Rho-GTPases and endoplasmic reticulum position the actin cluster. Nephrocyte diaphragm proteins localize to and regulate actin cluster organization. Perturbation of any of these inter-dependent components impairs ultrafiltration.
Collapse
Affiliation(s)
- Simi Muraleedharan
- Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore 560064, India
| | - Aksah Sam
- Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore 560064, India
| | - Helen Skaer
- Department of Zoology, University of Cambridge, Downing Street, Cambridge CB2 3EJ, UK
| | - Maneesha S Inamdar
- Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore 560064, India; Institute for Stem Cell Biology and Regenerative Medicine, GKVK, Bellary Road, Bangalore 560065, India.
| |
Collapse
|
49
|
Liu YC, Chun J. Prospects for Precision Medicine in Glomerulonephritis Treatment. Can J Kidney Health Dis 2018; 5:2054358117753617. [PMID: 29449955 PMCID: PMC5808958 DOI: 10.1177/2054358117753617] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2017] [Accepted: 11/12/2017] [Indexed: 02/06/2023] Open
Abstract
Background: Glomerulonephritis (GN) consists of a group of kidney diseases that are categorized based on shared histopathological features. The current classifications for GN make it difficult to distinguish the individual variability in presentation, disease progression, and response to treatment. GN is a significant cause of end-stage renal disease (ESRD), and improved therapies are desperately needed because current immunosuppressive therapies sometimes lack efficacy and can lead to significant toxicities. In recent years, the combination of high-throughput genetic approaches and technological advances has identified important regulators contributing to GN. Objectives: In this review, we summarize recent findings in podocyte biology and advances in experimental approaches that have opened the possibility of precision medicine in GN treatment. We provide an integrative basic science and clinical overview of new developments in GN research and the discovery of potential candidates for targeted therapies in GN. Findings: Advances in podocyte biology have identified many candidates for therapeutic targets and potential biomarkers of glomerular disease. The goal of precision medicine in GN is now being pursued with recent technological improvements in genetics, accessibility of biologic and clinical information with tissue biobanks, high-throughput analysis of large-scale data sets, and new human model systems such as kidney organoids. Conclusion: With advances in data collection, technologies, and experimental model systems, we now have vast tools available to pursue precision medicine in GN. We anticipate a growing number of studies integrating data from high-throughput analysis with the development of diagnostic tools and targeted therapies for GN in the near future.
Collapse
Affiliation(s)
- Yulu Cherry Liu
- Department of Cell Biology, Harvard Medical School, Boston, MA, USA
| | - Justin Chun
- Division of Nephrology, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA.,Division of Nephrology, Department of Medicine, University of Calgary, Alberta, Canada
| |
Collapse
|
50
|
Martin CE, Jones N. Nephrin Signaling in the Podocyte: An Updated View of Signal Regulation at the Slit Diaphragm and Beyond. Front Endocrinol (Lausanne) 2018; 9:302. [PMID: 29922234 PMCID: PMC5996060 DOI: 10.3389/fendo.2018.00302] [Citation(s) in RCA: 73] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/12/2018] [Accepted: 05/22/2018] [Indexed: 12/11/2022] Open
Abstract
Podocytes are a major component of the glomerular blood filtration barrier, and alterations to the morphology of their unique actin-based foot processes (FP) are a common feature of kidney disease. Adjacent FP are connected by a specialized intercellular junction known as the slit diaphragm (SD), which serves as the ultimate barrier to regulate passage of macromolecules from the blood. While the link between SD dysfunction and reduced filtration selectivity has been recognized for nearly 50 years, our understanding of the underlying molecular circuitry began only 20 years ago, sparked by the identification of NPHS1, encoding the transmembrane protein nephrin. Nephrin not only functions as the core component of the extracellular SD filtration network but also as a signaling scaffold via interactions at its short intracellular region. Phospho-regulation of several conserved tyrosine residues in this region influences signal transduction pathways which control podocyte cell adhesion, shape, and survival, and emerging studies highlight roles for nephrin phospho-dynamics in mechanotransduction and endocytosis. The following review aims to summarize the last 5 years of advancement in our knowledge of how signaling centered at nephrin directs SD barrier formation and function. We further provide insight on promising frontiers in podocyte biology, which have implications for SD signaling in the healthy and diseased kidney.
Collapse
|