1
|
Kuzmuk V, Pranke I, Rollason R, Butler M, Ding WY, Beesley M, Waters AM, Coward RJ, Sessions R, Tuffin J, Foster RR, Mollet G, Antignac C, Edelman A, Welsh GI, Saleem MA. A small molecule chaperone rescues keratin-8 mediated trafficking of misfolded podocin to correct genetic Nephrotic Syndrome. Kidney Int 2024; 105:744-758. [PMID: 37995908 DOI: 10.1016/j.kint.2023.11.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2023] [Revised: 10/02/2023] [Accepted: 11/10/2023] [Indexed: 11/25/2023]
Abstract
Podocin is a key membrane scaffolding protein of the kidney podocyte essential for intact glomerular filtration. Mutations in NPHS2, the podocin-encoding gene, represent the commonest form of inherited nephrotic syndrome (NS), with early, intractable kidney failure. The most frequent podocin gene mutation in European children is R138Q, causing retention of the misfolded protein in the endoplasmic reticulum. Here, we provide evidence that podocin R138Q (but not wild-type podocin) complexes with the intermediate filament protein keratin 8 (K8) thereby preventing its correct trafficking to the plasma membrane. We have also identified a small molecule (c407), a compound that corrects the Cystic Fibrosis Transmembrane Conductance Regulator protein defect, that interrupts this complex and rescues mutant protein mistrafficking. This results in both the correct localization of podocin at the plasma membrane and functional rescue in both human patient R138Q mutant podocyte cell lines, and in a mouse inducible knock-in model of the R138Q mutation. Importantly, complete rescue of proteinuria and histological changes was seen when c407 was administered both via osmotic minipumps or delivered orally prior to induction of disease or crucially via osmotic minipump two weeks after disease induction. Thus, our data constitute a therapeutic option for patients with NS bearing a podocin mutation, with implications for other misfolding protein disorders. Further studies are necessary to confirm our findings.
Collapse
Affiliation(s)
- Valeryia Kuzmuk
- Bristol Renal, Bristol Medical School, University of Bristol, Bristol, UK
| | - Iwona Pranke
- INSERM, U1151, Institut Necker Enfants Malades, INEM, Paris, France
| | - Ruth Rollason
- Bristol Renal, Bristol Medical School, University of Bristol, Bristol, UK
| | - Matthew Butler
- Bristol Renal, Bristol Medical School, University of Bristol, Bristol, UK
| | - Wen Y Ding
- Bristol Renal, Bristol Medical School, University of Bristol, Bristol, UK
| | - Matthew Beesley
- Department of Pathology, Gloucestershire Hospitals NHS Foundation Trust, Gloucester, UK
| | | | - Richard J Coward
- Bristol Renal, Bristol Medical School, University of Bristol, Bristol, UK
| | | | - Jack Tuffin
- Bristol Renal, Bristol Medical School, University of Bristol, Bristol, UK
| | - Rebecca R Foster
- Bristol Renal, Bristol Medical School, University of Bristol, Bristol, UK
| | - Géraldine Mollet
- Laboratoire des Maladies Rénales Héréditaires, Inserm UMR 1163, Institut Imagine, Université Paris Cité, Paris, France
| | - Corinne Antignac
- Laboratoire des Maladies Rénales Héréditaires, Inserm UMR 1163, Institut Imagine, Université Paris Cité, Paris, France
| | | | - Gavin I Welsh
- Bristol Renal, Bristol Medical School, University of Bristol, Bristol, UK
| | - Moin A Saleem
- Bristol Renal, Bristol Medical School, University of Bristol, Bristol, UK.
| |
Collapse
|
2
|
Ding WY, Kuzmuk V, Hunter S, Lay A, Hayes B, Beesley M, Rollason R, Hurcombe JA, Barrington F, Masson C, Cathery W, May C, Tuffin J, Roberts T, Mollet G, Chu CJ, McIntosh J, Coward RJ, Antignac C, Nathwani A, Welsh GI, Saleem MA. Adeno-associated virus gene therapy prevents progression of kidney disease in genetic models of nephrotic syndrome. Sci Transl Med 2023; 15:eabc8226. [PMID: 37556557 DOI: 10.1126/scitranslmed.abc8226] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Accepted: 07/21/2023] [Indexed: 08/11/2023]
Abstract
Gene therapy for kidney diseases has proven challenging. Adeno-associated virus (AAV) is used as a vector for gene therapy targeting other organs, with particular success demonstrated in monogenic diseases. We aimed to establish gene therapy for the kidney by targeting a monogenic disease of the kidney podocyte. The most common cause of childhood genetic nephrotic syndrome is mutations in the podocyte gene NPHS2, encoding podocin. We used AAV-based gene therapy to rescue this genetic defect in human and mouse models of disease. In vitro transduction studies identified the AAV-LK03 serotype as a highly efficient transducer of human podocytes. AAV-LK03-mediated transduction of podocin in mutant human podocytes resulted in functional rescue in vitro, and AAV 2/9-mediated gene transfer in both the inducible podocin knockout and knock-in mouse models resulted in successful amelioration of kidney disease. A prophylactic approach of AAV 2/9 gene transfer before induction of disease in conditional knockout mice demonstrated improvements in albuminuria, plasma creatinine, plasma urea, plasma cholesterol, histological changes, and long-term survival. A therapeutic approach of AAV 2/9 gene transfer 2 weeks after disease induction in proteinuric conditional knock-in mice demonstrated improvement in urinary albuminuria at days 42 and 56 after disease induction, with corresponding improvements in plasma albumin. Therefore, we have demonstrated successful AAV-mediated gene rescue in a monogenic renal disease and established the podocyte as a tractable target for gene therapy approaches.
Collapse
Affiliation(s)
- Wen Y Ding
- Bristol Renal, Bristol Medical School, Dorothy Hodgkin Building, University of Bristol, Bristol BS1 3NY, UK
| | - Valeryia Kuzmuk
- Bristol Renal, Bristol Medical School, Dorothy Hodgkin Building, University of Bristol, Bristol BS1 3NY, UK
- Purespring Therapeutics, Rolling Stock Yard, 188 York Way, London N7 9AS, UK
| | - Sarah Hunter
- Bristol Renal, Bristol Medical School, Dorothy Hodgkin Building, University of Bristol, Bristol BS1 3NY, UK
| | - Abigail Lay
- Bristol Renal, Bristol Medical School, Dorothy Hodgkin Building, University of Bristol, Bristol BS1 3NY, UK
| | - Bryony Hayes
- Bristol Renal, Bristol Medical School, Dorothy Hodgkin Building, University of Bristol, Bristol BS1 3NY, UK
| | - Matthew Beesley
- Department of Histopathology, Cheltenham General Hospital, Cheltenham GL53 7AN, UK
| | - Ruth Rollason
- Bristol Renal, Bristol Medical School, Dorothy Hodgkin Building, University of Bristol, Bristol BS1 3NY, UK
| | - Jennifer A Hurcombe
- Bristol Renal, Bristol Medical School, Dorothy Hodgkin Building, University of Bristol, Bristol BS1 3NY, UK
| | - Fern Barrington
- Bristol Renal, Bristol Medical School, Dorothy Hodgkin Building, University of Bristol, Bristol BS1 3NY, UK
| | - Catrin Masson
- Bristol Renal, Bristol Medical School, Dorothy Hodgkin Building, University of Bristol, Bristol BS1 3NY, UK
| | - William Cathery
- Bristol Renal, Bristol Medical School, Dorothy Hodgkin Building, University of Bristol, Bristol BS1 3NY, UK
| | - Carl May
- Bristol Renal, Bristol Medical School, Dorothy Hodgkin Building, University of Bristol, Bristol BS1 3NY, UK
| | - Jack Tuffin
- Purespring Therapeutics, Rolling Stock Yard, 188 York Way, London N7 9AS, UK
| | - Timothy Roberts
- Bristol Renal, Bristol Medical School, Dorothy Hodgkin Building, University of Bristol, Bristol BS1 3NY, UK
| | - Geraldine Mollet
- Laboratoire des Maladies Rénales Héréditaires, Inserm UMR 1163, Institut Imagine, Université Paris Cité, Paris 75015, France
| | - Colin J Chu
- Academic Unit of Ophthalmology, Bristol Medical School, Biomedical Sciences Building, University of Bristol, Bristol BS8 1TD, UK
| | - Jenny McIntosh
- Research Department of Haematology, UCL Cancer Institute, Paul O'Gorman Building, University College London, London WC1E 6BT, UK
| | - Richard J Coward
- Bristol Renal, Bristol Medical School, Dorothy Hodgkin Building, University of Bristol, Bristol BS1 3NY, UK
| | - Corinne Antignac
- Laboratoire des Maladies Rénales Héréditaires, Inserm UMR 1163, Institut Imagine, Université Paris Cité, Paris 75015, France
| | - Amit Nathwani
- Research Department of Haematology, UCL Cancer Institute, Paul O'Gorman Building, University College London, London WC1E 6BT, UK
| | - Gavin I Welsh
- Bristol Renal, Bristol Medical School, Dorothy Hodgkin Building, University of Bristol, Bristol BS1 3NY, UK
| | - Moin A Saleem
- Bristol Renal, Bristol Medical School, Dorothy Hodgkin Building, University of Bristol, Bristol BS1 3NY, UK
| |
Collapse
|
3
|
The Atypical Cyclin-Dependent Kinase 5 (Cdk5) Guards Podocytes from Apoptosis in Glomerular Disease While Being Dispensable for Podocyte Development. Cells 2021; 10:cells10092464. [PMID: 34572114 PMCID: PMC8470701 DOI: 10.3390/cells10092464] [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: 08/28/2021] [Revised: 09/10/2021] [Accepted: 09/13/2021] [Indexed: 12/03/2022] Open
Abstract
Cyclin-dependent kinase 5 (Cdk5) is expressed in terminally differentiated cells, where it drives development, morphogenesis, and survival. Temporal and spatial kinase activity is regulated by specific activators of Cdk5, dependent on the cell type and environmental factors. In the kidney, Cdk5 is exclusively expressed in terminally differentiated glomerular epithelial cells called podocytes. In glomerular disease, signaling mechanisms via Cdk5 have been addressed by single or combined conventional knockout of known specific activators of Cdk5. A protective, anti-apoptotic role has been ascribed to Cdk5 but not a developmental phenotype, as in terminally differentiated neurons. The effector kinase itself has never been addressed in animal models of glomerular disease. In the present study, conditional and inducible knockout models of Cdk5 were analyzed to investigate the role of Cdk5 in podocyte development and glomerular disease. While mice with podocyte-specific knockout of Cdk5 had no developmental defects and regular lifespan, loss of Cdk5 in podocytes increased susceptibility to glomerular damage in the nephrotoxic nephritis model. Glomerular damage was associated with reduced anti-apoptotic signals in Cdk5-deficient mice. In summary, Cdk5 acts primarily as master regulator of podocyte survival during glomerular disease and—in contrast to neurons—does not impact on glomerular development or maintenance.
Collapse
|
4
|
Papakrivopoulou E, Vasilopoulou E, Lindenmeyer MT, Pacheco S, Brzóska HŁ, Price KL, Kolatsi‐Joannou M, White KE, Henderson DJ, Dean CH, Cohen CD, Salama AD, Woolf AS, Long DA. Vangl2, a planar cell polarity molecule, is implicated in irreversible and reversible kidney glomerular injury. J Pathol 2018; 246:485-496. [PMID: 30125361 PMCID: PMC6282744 DOI: 10.1002/path.5158] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2018] [Revised: 08/02/2018] [Accepted: 08/10/2018] [Indexed: 12/11/2022]
Abstract
Planar cell polarity (PCP) pathways control the orientation and alignment of epithelial cells within tissues. Van Gogh-like 2 (Vangl2) is a key PCP protein that is required for the normal differentiation of kidney glomeruli and tubules. Vangl2 has also been implicated in modifying the course of acquired glomerular disease, and here, we further explored how Vangl2 impacts on glomerular pathobiology in this context. Targeted genetic deletion of Vangl2 in mouse glomerular epithelial podocytes enhanced the severity of not only irreversible accelerated nephrotoxic nephritis but also lipopolysaccharide-induced reversible glomerular damage. In each proteinuric model, genetic deletion of Vangl2 in podocytes was associated with an increased ratio of active-MMP9 to inactive MMP9, an enzyme involved in tissue remodelling. In addition, by interrogating microarray data from two cohorts of renal patients, we report increased VANGL2 transcript levels in the glomeruli of individuals with focal segmental glomerulosclerosis, suggesting that the molecule may also be involved in certain human glomerular diseases. These observations support the conclusion that Vangl2 modulates glomerular injury, at least in part by acting as a brake on MMP9, a potentially harmful endogenous enzyme. © 2018 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.
Collapse
MESH Headings
- Adult
- Animals
- Case-Control Studies
- Cell Polarity
- Cells, Cultured
- Disease Models, Animal
- Enzyme Activation
- Female
- Glomerulosclerosis, Focal Segmental/genetics
- Glomerulosclerosis, Focal Segmental/metabolism
- Glomerulosclerosis, Focal Segmental/pathology
- Glomerulosclerosis, Focal Segmental/physiopathology
- Humans
- Intracellular Signaling Peptides and Proteins/genetics
- Intracellular Signaling Peptides and Proteins/metabolism
- Kidney Glomerulus/metabolism
- Kidney Glomerulus/pathology
- Kidney Glomerulus/physiopathology
- Male
- Matrix Metalloproteinase 9/metabolism
- Membrane Proteins/genetics
- Membrane Proteins/metabolism
- Mice, Inbred C57BL
- Mice, Knockout
- Middle Aged
- Nephrosis, Lipoid/genetics
- Nephrosis, Lipoid/metabolism
- Nephrosis, Lipoid/pathology
- Nephrosis, Lipoid/physiopathology
- Nerve Tissue Proteins/deficiency
- Nerve Tissue Proteins/genetics
- Nerve Tissue Proteins/metabolism
- Podocytes/metabolism
- Podocytes/pathology
- Signal Transduction
- Young Adult
Collapse
Affiliation(s)
- Eugenia Papakrivopoulou
- Developmental Biology and Cancer ProgrammeUCL Great Ormond Street Institute of Child HealthLondonUK
| | - Elisavet Vasilopoulou
- Developmental Biology and Cancer ProgrammeUCL Great Ormond Street Institute of Child HealthLondonUK
- Medway School of PharmacyUniversity of KentChatham MaritimeUK
| | - Maja T Lindenmeyer
- Nephrological Center, Medical Clinic and Policlinic IVUniversity of MunichMunichGermany
- Department of MedicineUniversity Medical Center Hamburg‐EppendorfHamburgGermany
| | - Sabrina Pacheco
- Developmental Biology and Cancer ProgrammeUCL Great Ormond Street Institute of Child HealthLondonUK
| | - Hortensja Ł Brzóska
- Developmental Biology and Cancer ProgrammeUCL Great Ormond Street Institute of Child HealthLondonUK
| | - Karen L Price
- Developmental Biology and Cancer ProgrammeUCL Great Ormond Street Institute of Child HealthLondonUK
| | - Maria Kolatsi‐Joannou
- Developmental Biology and Cancer ProgrammeUCL Great Ormond Street Institute of Child HealthLondonUK
| | - Kathryn E White
- Electron Microscopy Research ServicesNewcastle UniversityNewcastle upon TyneUK
| | - Deborah J Henderson
- Cardiovascular Research CentreInstitute of Genetic Medicine, Newcastle UniversityNewcastle upon TyneUK
| | - Charlotte H Dean
- Inflammation Repair and Development SectionNational Heart and Lung Institute, Imperial College LondonLondonUK
| | - Clemens D Cohen
- Nephrological Center, Medical Clinic and Policlinic IVUniversity of MunichMunichGermany
| | - Alan D Salama
- University College London Centre for Nephrology, Royal Free HospitalLondonUK
| | - Adrian S Woolf
- Faculty of Biology Medicine and HealthSchool of Biological Sciences, University of ManchesterManchesterUK
- Royal Manchester Children's Hospital, Manchester University NHS Foundation Trust, Manchester Academic Health Science CentreManchesterUK
| | - David A Long
- Developmental Biology and Cancer ProgrammeUCL Great Ormond Street Institute of Child HealthLondonUK
| |
Collapse
|
5
|
Yu SMW, Nissaisorakarn P, Husain I, Jim B. Proteinuric Kidney Diseases: A Podocyte's Slit Diaphragm and Cytoskeleton Approach. Front Med (Lausanne) 2018; 5:221. [PMID: 30255020 PMCID: PMC6141722 DOI: 10.3389/fmed.2018.00221] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2018] [Accepted: 07/18/2018] [Indexed: 01/19/2023] Open
Abstract
Proteinuric kidney diseases are a group of disorders with diverse pathological mechanisms associated with significant losses of protein in the urine. The glomerular filtration barrier (GFB), comprised of the three important layers, the fenestrated glomerular endothelium, the glomerular basement membrane (GBM), and the podocyte, dictates that disruption of any one of these structures should lead to proteinuric disease. Podocytes, in particular, have long been considered as the final gatekeeper of the GFB. This specialized visceral epithelial cell contains a complex framework of cytoskeletons forming foot processes and mediate important cell signaling to maintain podocyte health. In this review, we will focus on slit diaphragm proteins such as nephrin, podocin, TRPC6/5, as well as cytoskeletal proteins Rho/small GTPases and synaptopodin and their respective roles in participating in the pathogenesis of proteinuric kidney diseases. Furthermore, we will summarize the potential therapeutic options targeting the podocyte to treat this group of kidney diseases.
Collapse
Affiliation(s)
- Samuel Mon-Wei Yu
- Department of Medicine, Jacobi Medical Center, Bronx, NY, United States
| | | | - Irma Husain
- Department of Medicine, James J. Peters VA Medical Center, Bronx, NY, United States
| | - Belinda Jim
- Department of Medicine, Jacobi Medical Center, Bronx, NY, United States.,Renal Division, Jacobi Medical Center, Bronx, NY, United States
| |
Collapse
|
6
|
In vivo RNA interference models of inducible and reversible Sirt1 knockdown in kidney cells. THE AMERICAN JOURNAL OF PATHOLOGY 2015; 184:1940-56. [PMID: 24952428 DOI: 10.1016/j.ajpath.2014.03.016] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/27/2013] [Revised: 02/26/2014] [Accepted: 03/06/2014] [Indexed: 02/07/2023]
Abstract
The silent mating type information regulation 2 homolog 1 gene (Sirt1) encodes an NAD-dependent deacetylase that modifies the activity of well-known transcriptional regulators affected in kidney diseases. Sirt1 is expressed in the kidney podocyte, but its function in the podocyte is not clear. Genetically engineered mice with inducible and reversible Sirt1 knockdown in widespread, podocyte-specific, or tubular-specific patterns were generated. We found that mice with 80% knockdown of renal Sirt1 expression have normal glomerular function under the basal condition. When challenged with doxorubicin (Adriamycin), these mice develop marked albuminuria, glomerulosclerosis, mitochondrial injury, and impaired autophagy of damaged mitochondria. Reversal of Sirt1 knockdown during the early phase of Adriamycin-induced nephropathy prevented the progression of glomerular injury and reduced the accumulation of dysmorphic mitochondria in podocytes but did not reverse the progression of albuminuria and glomerulosclerosis. Sirt1 knockdown mice with diabetes mellitus, which is known to cause mitochondrial dysfunction in the kidney, developed more albuminuria and mitochondrial dysfunction compared with diabetic mice without Sirt1 knockdown. In conclusion, these results demonstrate that our RNA interference-mediated Sirt1 knockdown models are valid and versatile tools for characterizing the function of Sirt1 in the kidney; Sirt1 plays a role in homeostatic maintenance of podocytes under the condition of mitochondrial stress/injury.
Collapse
|
7
|
Li X, Chuang PY, D'Agati VD, Dai Y, Yacoub R, Fu J, Xu J, Taku O, Premsrirut PK, Holzman LB, He JC. Nephrin Preserves Podocyte Viability and Glomerular Structure and Function in Adult Kidneys. J Am Soc Nephrol 2015; 26:2361-77. [PMID: 25644109 DOI: 10.1681/asn.2014040405] [Citation(s) in RCA: 83] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2014] [Accepted: 11/19/2014] [Indexed: 01/12/2023] Open
Abstract
Nephrin is required during kidney development for the maturation of podocytes and formation of the slit diaphragm junctional complex. Because nephrin expression is downregulated in acquired glomerular diseases, nephrin deficiency is considered a pathologic feature of glomerular injury. However, whether nephrin deficiency exacerbates glomerular injury in glomerular diseases has not been experimentally confirmed. Here, we generated mice with inducible RNA interference-mediated nephrin knockdown. Short-term nephrin knockdown (6 weeks), starting after the completion of kidney development at 5 weeks of age, did not affect glomerular structure or function. In contrast, mice with long-term nephrin knockdown (20 weeks) developed mild proteinuria, foot process effacement, filtration slit narrowing, mesangial hypercellularity and sclerosis, glomerular basement membrane thickening, subendothelial zone widening, and podocyte apoptosis. When subjected to an acquired glomerular insult induced by unilateral nephrectomy or doxorubicin, mice with short-term nephrin knockdown developed more severe glomerular injury compared with mice without nephrin knockdown. Additionally, nephrin-knockdown mice developed more exaggerated glomerular enlargement when subjected to unilateral nephrectomy and more podocyte apoptosis and depletion after doxorubicin challenge. AKT phosphorylation, which is a slit diaphragm-mediated and nephrin-dependent pathway in the podocyte, was markedly reduced in mice with long-term or short-term nephrin knockdown challenged with uninephrectomy or doxorubicin. Taken together, our data establish that under the basal condition and in acquired glomerular diseases, nephrin is required to maintain slit diaphragm integrity and slit diaphragm-mediated signaling to preserve glomerular function and podocyte viability in adult mice.
Collapse
Affiliation(s)
- Xuezhu Li
- Department of Medicine/Nephrology, Icahn School of Medicine at Mount Sinai, New York, New York; Department of Nephrology; Shanghai East Hospital, Tongji University School of Medicine, Shanghai, China
| | - Peter Y Chuang
- Department of Medicine/Nephrology, Icahn School of Medicine at Mount Sinai, New York, New York;
| | - Vivette D D'Agati
- Department of Pathology, College of Physicians and Surgeons, Columbia University, New York, New York
| | - Yan Dai
- Department of Medicine/Nephrology, Icahn School of Medicine at Mount Sinai, New York, New York; Department of Nephrology, Shanghai First Municipal Hospital, Shanghai Jiaotao University School of Medicine; Shanghai, China
| | - Rabi Yacoub
- Department of Medicine/Nephrology, Icahn School of Medicine at Mount Sinai, New York, New York
| | - Jia Fu
- Research Institute of Nephrology, Jinling Hospital, Nanjing University School of Medicine, Nanjing, China
| | - Jin Xu
- Department of Medicine/Nephrology, Icahn School of Medicine at Mount Sinai, New York, New York
| | - Oltjon Taku
- State University of New York at University at Binghamton, Binghamton, New York
| | | | - Lawrence B Holzman
- Renal Electrolyte and Hypertension Division, University of Pennsylvania, Perelman School of Medicine, Philadelphia, Pennsylvania; and
| | - John Cijiang He
- Department of Medicine/Nephrology, Icahn School of Medicine at Mount Sinai, New York, New York; Renal Section, James J Peter Veterans Administration Medical Center, Bronx, New York
| |
Collapse
|
8
|
Ihara KI, Asanuma K, Fukuda T, Ohwada S, Yoshida M, Nishimori K. MAGI-2 is critical for the formation and maintenance of the glomerular filtration barrier in mouse kidney. THE AMERICAN JOURNAL OF PATHOLOGY 2014; 184:2699-708. [PMID: 25108225 DOI: 10.1016/j.ajpath.2014.06.019] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2014] [Revised: 05/29/2014] [Accepted: 06/26/2014] [Indexed: 11/20/2022]
Abstract
Membrane-associated guanylate kinase inverted 2 (MAGI-2) is a tight junction protein in epithelial tissues. We previously reported the detailed expression patterns of MAGI-2 in mouse tissues, including kidney podocytes, based on results obtained from Venus knock-in mice for Magi2 locus. In the present study, homozygous deletion of the Magi2 gene in mice caused neonatal lethality, which was explained by podocyte morphological abnormalities and anuria. Immunohistological analysis showed that loss of MAGI-2 function induced a significant decrease in nephrin and dendrin at the slit diaphragm of the kidney, although other components of the slit diaphragm were unchanged. Furthermore, nuclear translocation of dendrin was observed in the podocytes of the MAGI-2-null mutants, along with enhanced expression of cathepsin L, which is reported to be critical for rearrangement of the actin cytoskeleton in podocytes. Expression analysis of the null mutants showed that loss of MAGI-2 function induces abnormal expression of various types of adhesion-related molecules. The present study is the first to demonstrate that MAGI-2 has a critical role in maintaining the functional structure of the slit diaphragm and that this molecule has an essential role in the functioning of the kidney filtration barrier.
Collapse
Affiliation(s)
- Kan-Ichiro Ihara
- Laboratory of Molecular Biology, Department of Molecular and Cell Biology, Graduate School of Agricultural Science, Tohoku University, Sendai
| | - Katsuhiko Asanuma
- Division of Nephrology, Department of Internal Medicine, Juntendo University School of Medicine, Tokyo; Laboratory for Kidney Research, Medical Innovation Center, Graduate School of Medicine, Kyoto University, Kyoto
| | - Tomokazu Fukuda
- Laboratory of Animal Breeding and Genetics, Department of Animal Biology, Graduate School of Agricultural Science, Tohoku University, Sendai
| | - Shyuichi Ohwada
- Laboratory of Functional Morphology, Department of Animal Biology, Graduate School of Agricultural Science, Tohoku University, Sendai
| | - Midori Yoshida
- Division of Pathology, National Institute of Health Sciences, Tokyo, Japan
| | - Katsuhiko Nishimori
- Laboratory of Molecular Biology, Department of Molecular and Cell Biology, Graduate School of Agricultural Science, Tohoku University, Sendai.
| |
Collapse
|
9
|
McCarthy KJ, Wassenhove-McCarthy DJ. The glomerular basement membrane as a model system to study the bioactivity of heparan sulfate glycosaminoglycans. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2012; 18:3-21. [PMID: 22258721 PMCID: PMC3351113 DOI: 10.1017/s1431927611012682] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The glomerular basement membrane and its associated cells are critical elements in the renal ultrafiltration process. Traditionally the anionic charge associated with several carbohydrate moieties in the glomerular basement membrane are thought to form a charge selective barrier that restricts the transmembrane flux of anionic proteins across the glomerular basement membrane into the urinary space. The charge selective function, along with the size selective component of the basement membrane, serves to limit the efflux of plasma proteins from the capillary lumen. Heparan sulfate glycosaminoglycans are anionically charged carbohydrate structures attached to proteoglycan core proteins and have a role in establishing the charge selective function of the glomerular basement membrane. Although there are a large number of studies in the literature that support this concept, the results of several recent studies using molecular genetic approaches to minimize the anionic charge of the glomerular basement membrane would suggest that the role of heparan sulfate glycosaminoglycans in the glomerular capillary wall are still not yet entirely resolved, suggesting that this research area still requires new and novel exploration.
Collapse
Affiliation(s)
- Kevin J McCarthy
- Department of Pathology, LSU Health Sciences Center-Shreveport, 1501 Kings Highway, Shreveport, LA 71130-3932, USA.
| | | |
Collapse
|
10
|
Acharya A, Baek ST, Banfi S, Eskiocak B, Tallquist MD. Efficient inducible Cre-mediated recombination in Tcf21 cell lineages in the heart and kidney. Genesis 2011; 49:870-7. [PMID: 21432986 DOI: 10.1002/dvg.20750] [Citation(s) in RCA: 115] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2010] [Revised: 12/17/2010] [Accepted: 03/12/2011] [Indexed: 11/10/2022]
Abstract
Tcf21 is a Class II bHLH family member with essential roles in the formation of the lungs, kidneys, gonads, spleen, and heart. Here, we report the utility of a mouse line with targeted insertion of a tamoxifen-inducible Cre recombinase, MerCreMer at the Tcf21 locus. This mouse line will permit the inducible expression of Cre recombinase in Tcf21-expressing cells. Using ROSA26 reporter mice, we show that Cre recombinase is specifically and robustly activated in multiple Tcf21-expressing tissues during embryonic and postnatal development. The expression profile in the kidney is particularly dynamic with the ability to cause recombination in mesangial cells at one time of induction and podocytes at another time. These features make the Tcf21-driven inducible Cre line (Tcf21(iCre) ) a valuable genetic tool for spatiotemporal gene function analysis and lineage tracing of cells in the heart, kidney, cranial muscle, and gonads.
Collapse
Affiliation(s)
- Asha Acharya
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, Texas 75390-9148, USA
| | | | | | | | | |
Collapse
|
11
|
Wang J, Wang Y, Long J, Chang BHJ, Wilson MH, Overbeek P, Danesh FR. Tamoxifen-inducible podocyte-specific iCre recombinase transgenic mouse provides a simple approach for modulation of podocytes in vivo. Genesis 2010; 48:446-51. [PMID: 20641128 DOI: 10.1002/dvg.20635] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
We report the generation and initial characterization of a mouse line expressing tamoxifen-inducible improved Cre (iCre) recombinase (iCre-ER(T2)) under the regulation of NPHS2 (podocin) gene promoter. The resulting transgenic mouse line was named podocin-iCreER(T2) mice. The efficiency of iCre activity was confirmed by crossing podocin-iCreER(T2) with the ROSA26 reporter mouse. By using the floxed ROSA reporter mice, we found that tamoxifen specifically induced recombination in the kidneys. In the absence of tamoxifen, recombination was undetectable in podocin-iCreER(T2);ROSA26 mice. However, following intraperitoneal injection of tamoxifen, selective recombination was observed in the podocytes of adult animals. We further examined the efficiency of recombination by assessing various tamoxifen exposure regimens in adult mice. These results suggest that podocin-iCre-ER(T2) mouse provides an excellent genetic tool to examine the function of candidate genes in podocytes in a spatially and temporally-restricted manner.
Collapse
Affiliation(s)
- Jinrong Wang
- Division of Nephrology, Department of Medicine, Baylor College of Medicine, Houston, Texas 77030, USA
| | | | | | | | | | | | | |
Collapse
|
12
|
Krall P, Canales CP, Kairath P, Carmona-Mora P, Molina J, Carpio JD, Ruiz P, Mezzano SA, Li J, Wei C, Reiser J, Young JI, Walz K. Podocyte-specific overexpression of wild type or mutant trpc6 in mice is sufficient to cause glomerular disease. PLoS One 2010; 5:e12859. [PMID: 20877463 PMCID: PMC2942896 DOI: 10.1371/journal.pone.0012859] [Citation(s) in RCA: 108] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2010] [Accepted: 08/24/2010] [Indexed: 02/04/2023] Open
Abstract
Mutations in the TRPC6 calcium channel (Transient receptor potential channel 6) gene have been associated with familiar forms of Focal and Segmental Glomerulosclerosis (FSGS) affecting children and adults. In addition, acquired glomerular diseases are associated with increased expression levels of TRPC6. However, the exact role of TRPC6 in the pathogenesis of FSGS remains to be elucidated. In this work we describe the generation and phenotypic characterization of three different transgenic mouse lines with podocyte-specific overexpression of the wild type or any of two mutant forms of Trpc6 (P111Q and E896K) previously related to FSGS. Consistent with the human phenotype a non-nephrotic range of albuminuria was detectable in almost all transgenic lines. The histological analysis demonstrated that the transgenic mice developed a kidney disease similar to human FSGS. Differences of 2-3 folds in the presence of glomerular lesions were found between the non transgenic and transgenic mice expressing Trpc6 in its wild type or mutant forms specifically in podocytes. Electron microscopy of glomerulus from transgenic mice showed extensive podocyte foot process effacement. We conclude that overexpression of Trpc6 (wild type or mutated) in podocytes is sufficient to cause a kidney disease consistent with FSGS. Our results contribute to reinforce the central role of podocytes in the etiology of FSGS. These mice constitute an important new model in which to study future therapies and outcomes of this complex disease.
Collapse
Affiliation(s)
- Paola Krall
- Centro de Estudios Científicos (CECS), Valdivia, Chile
- Universidad Austral de Chile, Valdivia, Chile
| | - Cesar P. Canales
- Centro de Estudios Científicos (CECS), Valdivia, Chile
- John P. Hussman Institute for Human Genomics, University of Miami, Miami, Florida, United States of America
| | - Pamela Kairath
- Centro de Estudios Científicos (CECS), Valdivia, Chile
- Universidad Austral de Chile, Valdivia, Chile
| | - Paulina Carmona-Mora
- Centro de Estudios Científicos (CECS), Valdivia, Chile
- John P. Hussman Institute for Human Genomics, University of Miami, Miami, Florida, United States of America
| | | | - J. Daniel Carpio
- Institute of Anatomy, Histology and Pathology, School of Medicine, Universidad Austral, Valdivia, Chile
- Nephrology Laboratory, School of Medicine, Universidad Austral, Valdivia, Chile
| | - Phillip Ruiz
- Department of Pathology, Leonard Miller School of Medicine, University of Miami, Miami, Florida, United States of America
| | - Sergio A. Mezzano
- Nephrology Laboratory, School of Medicine, Universidad Austral, Valdivia, Chile
| | - Jing Li
- Division of Nephrology and Hypertension, Leonard Miller School of Medicine, University of Miami, Miami, Florida, United States of America
| | - Changli Wei
- Division of Nephrology and Hypertension, Leonard Miller School of Medicine, University of Miami, Miami, Florida, United States of America
| | - Jochen Reiser
- Division of Nephrology and Hypertension, Leonard Miller School of Medicine, University of Miami, Miami, Florida, United States of America
| | - Juan I. Young
- Centro de Estudios Científicos (CECS), Valdivia, Chile
- John P. Hussman Institute for Human Genomics, University of Miami, Miami, Florida, United States of America
- CIN (Centro de Ingeniería de la Innovación CECS), Valdivia, Chile
| | - Katherina Walz
- Centro de Estudios Científicos (CECS), Valdivia, Chile
- John P. Hussman Institute for Human Genomics, University of Miami, Miami, Florida, United States of America
- * E-mail:
| |
Collapse
|
13
|
Heikkilä E, Juhila J, Lassila M, Messing M, Perälä N, Lehtonen E, Lehtonen S, Sjef Verbeek J, Holthofer H. beta-Catenin mediates adriamycin-induced albuminuria and podocyte injury in adult mouse kidneys. Nephrol Dial Transplant 2010; 25:2437-46. [PMID: 20237062 DOI: 10.1093/ndt/gfq076] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND Glomerular slit diaphragm (SD) represents a modified adherens junction composed of molecules belonging to both immunoglobulin and cadherin superfamilies. Cadherins associate with the cytosolic scaffolding protein beta-catenin, but the precise role of beta-catenin in mature or injured podocytes is not known. METHODS The conditional podocyte-specific beta-catenin-deficient mouse line was generated using the doxycycline-inducible Cre-loxP system. Expression of the beta-catenin-deficient gene was turned off at the age of 8 weeks by doxycycline treatment and the kidney phenotype was analysed. In addition, beta-catenin-deficient and control mice were treated with adriamycin (ADR) and analysed for albuminuria and morphological alterations. RESULTS Deletion of beta-catenin in mature podocytes did not change the morphology of podocytes nor did it lead to albuminuria. However, lack of beta-catenin attenuated albuminuria after ADR treatment. Electron microscopic examination showed increased podocyte foot process effacement associated with SD abnormalities in ADR-treated control mice compared to beta-catenin-deficient mice. CONCLUSIONS These results show that beta-catenin in podocytes is dispensable for adult mice, but appears to be important in modulating the SD during ADR-induced perturbation of the filtration barrier.
Collapse
Affiliation(s)
- Eija Heikkilä
- Haartman Institute, Department of Bacteriology and Immunology, University of Helsinki, Finland
| | | | | | | | | | | | | | | | | |
Collapse
|
14
|
|
15
|
Yokoi H, Kasahara M, Mukoyama M, Mori K, Kuwahara K, Fujikura J, Arai Y, Saito Y, Ogawa Y, Kuwabara T, Sugawara A, Nakao K. Podocyte-specific expression of tamoxifen-inducible Cre recombinase in mice. Nephrol Dial Transplant 2010; 25:2120-4. [PMID: 20150167 DOI: 10.1093/ndt/gfq029] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Podocytes play an important role in maintaining normal glomerular function. A podocyte-specific conditional knockout technology has been established by the use of transgenic mice expressing a podocyte-specific Cre recombinase to clarify the role of genes expressed in the podocytes. However, it may be difficult to examine the role of genes in certain pathologic conditions using conventional podocyte-specific knockout mice because they may be embryonically lethal or exhibit congenital renal abnormality. METHODS To introduce a temporal control in the genetic experiments targeting the podocyte, we constructed tamoxifen-inducible Cre recombinase (CreER(T2)) transgenic mice under the control of podocyte-specific promoter, 2.5-kb fragment of the human podocin (NPHS2) gene. The specificity and efficiency of Cre activity were examined by crossing NPHS2-CreER(T2) with the ROSA26 reporter (R26R) mouse in which a floxed-stop cassette has been placed upstream of the beta-galactosidase gene. Four-week-old double-mutant mice (NPHS2-CreER(T2)/R26R) were intraperitoneally administered with 0.5 mg of 4-hydroxytamoxifen (4-OHT) for three consecutive days. RESULTS NPHS2-CreER(T2)/R26R treated with 4-OHT expressed beta-galactosidase specifically in 85% of the podocytes in glomeruli. Expression of Cre recombinase mRNA was mostly restricted to the kidney, especially in glomeruli. CONCLUSIONS In conclusion, we have successfully generated podocyte-specific inducible Cre transgenic mice by tamoxifen administration. These mice allow us to disrupt the genes specifically in the podocytes after birth.
Collapse
Affiliation(s)
- Hideki Yokoi
- Department of Medicine and Clinical Science, Kyoto University Graduate School of Medicine, Kyoto, Kyoto, Japan
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
16
|
Juhila J, Lassila M, Roozendaal R, Lehtonen E, Messing M, Langer B, Kerjaschki D, Verbeek JS, Holthofer H. Inducible nephrin transgene expression in podocytes rescues nephrin-deficient mice from perinatal death. THE AMERICAN JOURNAL OF PATHOLOGY 2009; 176:51-63. [PMID: 19948823 DOI: 10.2353/ajpath.2010.080843] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Mutations leading to nephrin loss result in massive proteinuria both in humans and mice. Early perinatal lethality of conventional nephrin knockout mice makes it impossible to determine the role of nephrin protein in the adult kidney and in extra-renal tissues. Herein, we studied whether podocyte-specific, doxycycline-inducible, rat nephrin expression can rescue nephrin-deficient mice from perinatal lethality. Fourteen littermates out of 72 lacked endogenous nephrin and expressed transgenic rat nephrin. Six of these rescued mice survived until 6 weeks of age, whereas the nephrin-deficient pups died before the age of 5 days. The rescued mice were smaller, developed proteinuria, and showed histological abnormalities in the kidney. Despite foot process effacement, slit diaphragms were observed. Importantly, the expression and localization of several proteins associated with the signaling capacity of nephrin or the regulation of the expression of nephrin were changed in the podocytes. Indeed, all rescued mice showed impaired locomotor activity and distinct histological abnormalities in the cerebellum, and the male mice were also infertile and showed genital malformations. These observations are consistent with normal nephrin expression in the testis and cerebellum. These observations indicate that podocyte-specific expression of rat nephrin can rescue nephrin-deficient mice from perinatal death, but is not sufficient for full complementation.
Collapse
Affiliation(s)
- Juuso Juhila
- Haartman Institute, Department of Bacteriology and Immunology, University of Helsinki, Helsinki, Finland
| | | | | | | | | | | | | | | | | |
Collapse
|
17
|
Transgenic mice expressing nitroreductase gene under the control of the podocin promoter: a new murine model of inductible glomerular injury. Virchows Arch 2009; 456:325-37. [PMID: 19806361 DOI: 10.1007/s00428-009-0840-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2009] [Revised: 09/08/2009] [Accepted: 09/18/2009] [Indexed: 10/20/2022]
Abstract
The present work identifies a new mouse model of inductible acute glomerular injury leading to focal segmental glomerulonephritis. We take advantage of the suicide gene/prodrug nitroreductase/CB1954 combination, in which nitroreductase converts CB1954, a monofunctional alkylating agent, into its toxic form. We generate two lines of transgenic mice in which the nitroreductase gene was placed under the control of the podocyte-specific gene podocin. The functional analysis of transgenic mice lines showed that CB1954 treatment induced a severe but transitory proteinuria. Sequential histopathological analysis was performed on serial kidney biopsies. Injured glomeruli showed acute lesions with early podocyte vacuolization and detachment, podocyte apoptosis, and cellular proliferation leading to a marked hypercellularity of the urinary space that was associated with collapsing of the glomerular tuft. After 1 month, progressive scarring lead to focal segmental glomerulosclerosis with fibrous capsular adhesion, hyalinosis, and podocytosis associated with interstitial fibrosis. The phenotype of podocytes was changed exhibiting dedifferentiation characterized by the loss of podocyte specific proteins/transcription factor and the expression of injury markers. Bowman's capsule cells were also involved in the cellular changes in a manner suggesting epithelial to mesenchymal transition. This model of podocyte injury in transgenic mice provides new insights into the cellular mechanisms of podocytopathies and their progression to scarring.
Collapse
|
18
|
Pitera JE, Scambler PJ, Woolf AS. Fras1, a basement membrane-associated protein mutated in Fraser syndrome, mediates both the initiation of the mammalian kidney and the integrity of renal glomeruli. Hum Mol Genet 2008; 17:3953-64. [PMID: 18787044 PMCID: PMC2638576 DOI: 10.1093/hmg/ddn297] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
FRAS1 is mutated in some individuals with Fraser syndrome (FS) and the encoded protein is expressed in embryonic epidermal cells, localizing in their basement membrane (BM). Syndactyly and cryptophthalmos in FS are sequelae of skin fragility but the bases for associated kidney malformations are unclear. We demonstrate that Fras1 is expressed in the branching ureteric bud (UB), and that renal agenesis occurs in homozygous Fras1 null mutant blebbed (bl) mice on a C57BL6J background. In vivo, the bl/bl bud fails to invade metanephric mesenchyme which undergoes involution, events replicated in organ culture. The expression of glial cell line-derived neurotrophic factor and growth-differentiation factor 11 was defective in bl/bl renal primordia in vivo, whereas, in culture, the addition of either growth factor restored bud invasion into the mesenchyme. Mutant primordia also showed deficient expression of Hoxd11 and Six2 transcription factors, whereas the activity of bone morphogenetic protein 4, an anti-branching molecule, was upregulated. In wild types, Fras1 was also expressed by nascent nephrons. Foetal glomerular podocytes expressed Fras1 transcripts and Fras1 immunolocalized in a glomerular BM-like pattern. On a mixed background, bl mutants, and also compound mutants for bl and my, another bleb strain, sometimes survive into adulthood. These mice have two kidneys, which contain subsets of glomeruli with perturbed nephrin, podocin, integrin α3 and fibronectin expression. Thus, Fras1 protein coats branching UB epithelia and is strikingly upregulated in the nephron lineage after mesenchymal/epithelial transition. Fras1 deficiency causes defective interactions between the bud and mesenchyme, correlating with disturbed expression of key nephrogenic molecules. Furthermore, Fras1 may also be required for the formation of normal glomeruli.
Collapse
Affiliation(s)
- Jolanta E Pitera
- Nephro-Urology Unit, UCL Institute of Child Health, London WC1 N 1EH, UK
| | | | | |
Collapse
|
19
|
Kohan DE. Progress in gene targeting: using mutant mice to study renal function and disease. Kidney Int 2008; 74:427-37. [PMID: 18418351 DOI: 10.1038/ki.2008.146] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Genetic engineering in mice has provided much information about gene function in renal health and disease. This knowledge has largely come from conventional transgenic approaches. Recently, methods have been developed to control the cell type, timing and reversibility of target gene expression. Advances in identifying promoters conferring renal cell-specific gene regulation in vivo have greatly facilitated interpretation of gene targeting studies. Site-specific recombinases have permitted cell-specific knockout of genes; Cre is the preeminent recombinase, but recent progress with other recombinases, include Flp and PhiC31, will likely increase the usefulness of this class of enzymes. Temporally regulated gene expression, particularly using doxycycline- and tamoxifen-inducible systems, holds great promise for avoiding developmental effects of gene mutations as well as facilitating comparison of the same animal's phenotype before and after gene modification. RNA interference is undergoing tremendous growth and has great potential for achieving gene knockdown quickly and reversibly. To date, however, the utility of these systems in modifying renal function in transgenic mice remains unproven. Finally, new gene targeting tools are in development that may substantially simplify generation of transgenic animals. This review discusses the state-of-the-art in gene targeting in the kidney, reviewing function, indications and limitations of the molecular biologic tools.
Collapse
Affiliation(s)
- Donald E Kohan
- Division of Nephrology, Department of Internal Medicine, University of Utah Health Sciences Center, Salt Lake City, Utah 84132, USA.
| |
Collapse
|
20
|
Sun Y, Chen X, Xiao D. Tetracycline-inducible expression systems: new strategies and practices in the transgenic mouse modeling. Acta Biochim Biophys Sin (Shanghai) 2007; 39:235-46. [PMID: 17417678 DOI: 10.1111/j.1745-7270.2007.00258.x] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Abstract
To accurately analyze the function of transgene(s) of interest in transgenic mice, and to generate credible transgenic animal models for multifarious human diseases to precisely mimic human disease states, it is critical to tightly regulate gene expression in the animals in a conditional manner. The ability to turn gene expression on or off in the restricted cells or tissues at specific time permits unprecedented flexibility in dissecting gene functions in health and disease. Pioneering studies in conditional transgene expression have brought about the development of a wide variety of controlled gene expression systems, which meet this criterion. Among them, the tetracycline-controlled expression systems (e.g. Tet-off system and Tet-on system) have been used extensively in vitro and in vivo. In recent years, some strategies derived from tetracycline-inducible system alone, as well as the combined use of Tet-based systems and Cre/lox P switching gene expression system, have been newly developed to allow more flexibility for exploring gene functions in health and disease, and produce credible transgenic animal models for various human diseases. In this review these newly developed strategies are discussed.
Collapse
Affiliation(s)
- Yan Sun
- Center of Experimental Animals, Sun Yat-Sen University, Guangzhou 510080, China
| | | | | |
Collapse
|
21
|
Abstract
The glomerular filtration barrier consists of the fenestrated endothelium, the glomerular basement membrane and the terminally differentiated visceral epithelial cells known as podocytes. It is now widely accepted that damage to, or originating within, the podocytes is a key event that initiates progression towards sclerosis in many glomerular diseases. A wide variety of strategies have been employed by investigators from many scientific disciplines to study the podocyte. Although invaluable insights have accrued from conventional approaches, including cell culture and biochemical-based methods, many renal researchers continue to rely upon the mouse to address the form and function of the podocyte. This review summarizes how genetic manipulation in the mouse has advanced our understanding of the podocyte in relation to the maintenance of the glomerular filtration barrier in health and disease.
Collapse
Affiliation(s)
- Jean-Louis R Michaud
- Kidney Research Centre and Molecular Medicine Program, Ottawa Health Research Institute, University of Ottawa, Ottawa, Ontario, Canada
| | | |
Collapse
|