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Mitrotti A, Giliberti M, Di Leo V, di Bari I, Pontrelli P, Gesualdo L. Hidden genetics behind glomerular scars: an opportunity to understand the heterogeneity of focal segmental glomerulosclerosis? Pediatr Nephrol 2024; 39:1685-1707. [PMID: 37728640 PMCID: PMC11026212 DOI: 10.1007/s00467-023-06046-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/03/2023] [Revised: 05/02/2023] [Accepted: 05/30/2023] [Indexed: 09/21/2023]
Abstract
Focal segmental glomerulosclerosis (FSGS) is a complex disease which describes different kinds of kidney defects, not exclusively linked with podocyte defects. Since nephrin mutation was first described in association with early-onset nephrotic syndrome (NS), many advancements have been made in understanding genetic patterns associated with FSGS. New genetic causes of FSGS have been discovered, displaying unexpected genotypes, and recognizing possible site of damage. Many recent large-scale sequencing analyses on patients affected by idiopathic chronic kidney disease (CKD), kidney failure (KF) of unknown origin, or classified as FSGS, have revealed collagen alpha IV genes, as one of the most frequent sites of pathogenic mutations. Also, recent interest in complex and systemic lysosomal storage diseases, such as Fabry disease, has highlighted GLA mutations as possible causes of FSGS. Tubulointerstitial disease, recently classified by KDIGO based on genetic subtypes, when associated with UMOD variants, may phenotypically gain FSGS features, as well as ciliopathy genes or others, otherwise leading to completely different phenotypes, but found carrying pathogenic variants with associated FSGS phenotype. Thus, glomerulosclerosis may conceal different heterogeneous conditions. When a kidney biopsy is performed, the principal objective is to provide an accurate diagnosis. The broad spectrum of phenotypic expression and genetic complexity is demonstrating that a combined path of management needs to be applied. Genetic investigation should not be reserved only to selected cases, but rather part of medical management, integrating with clinical and renal pathology records. FSGS heterogeneity should be interpreted as an interesting opportunity to discover new pathways of CKD, requiring prompt genotype-phenotype correlation. In this review, we aim to highlight how FSGS represents a peculiar kidney condition, demanding multidisciplinary management, and in which genetic analysis may solve some otherwise unrevealed idiopathic cases. Unfortunately there is not a uniform correlation between specific mutations and FSGS morphological classes, as the same variants may be identified in familial cases or sporadic FSGS/NS or manifest a variable spectrum of the same disease. These non-specific features make diagnosis challenging. The complexity of FSGS genotypes requires new directions. Old morphological classification does not provide much information about the responsible cause of disease and misdiagnoses may expose patients to immunosuppressive therapy side effects, mistaken genetic counseling, and misguided kidney transplant programs.
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Affiliation(s)
- Adele Mitrotti
- Precision and Regenerative Medicine and Ionian Area, Nephrology, Dialysis and Transplantation Unit, Department of Emergency and Organ Transplantation, University of Bari Aldo Moro, Bari, Italy.
| | - Marica Giliberti
- Precision and Regenerative Medicine and Ionian Area, Nephrology, Dialysis and Transplantation Unit, Department of Emergency and Organ Transplantation, University of Bari Aldo Moro, Bari, Italy
| | - Vincenzo Di Leo
- Precision and Regenerative Medicine and Ionian Area, Nephrology, Dialysis and Transplantation Unit, Department of Emergency and Organ Transplantation, University of Bari Aldo Moro, Bari, Italy
| | - Ighli di Bari
- Precision and Regenerative Medicine and Ionian Area, Nephrology, Dialysis and Transplantation Unit, Department of Emergency and Organ Transplantation, University of Bari Aldo Moro, Bari, Italy
| | - Paola Pontrelli
- Precision and Regenerative Medicine and Ionian Area, Nephrology, Dialysis and Transplantation Unit, Department of Emergency and Organ Transplantation, University of Bari Aldo Moro, Bari, Italy
| | - Loreto Gesualdo
- Precision and Regenerative Medicine and Ionian Area, Nephrology, Dialysis and Transplantation Unit, Department of Emergency and Organ Transplantation, University of Bari Aldo Moro, Bari, Italy
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Bonilla M, Efe O, Selvaskandan H, Lerma EV, Wiegley N. A Review of Focal Segmental Glomerulosclerosis Classification With a Focus on Genetic Associations. Kidney Med 2024; 6:100826. [PMID: 38765809 PMCID: PMC11099322 DOI: 10.1016/j.xkme.2024.100826] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/22/2024] Open
Abstract
Focal segmental glomerulosclerosis (FSGS) defines a distinct histologic pattern observed in kidney tissue that is linked to several distinct underlying causes, all converging on the common factor of podocyte injury. It presents a considerable challenge in terms of classification because of its varied underlying causes and the limited correlation between histopathology and clinical outcomes. Critically, precise nomenclature is key to describe and delineate the pathogenesis, subsequently guiding the selection of suitable and precision therapies. A proposed pathomechanism-based approach has been suggested for FSGS classification. This approach differentiates among primary, secondary, genetic, and undetermined causes, aiming to provide clarity. Genetic FSGS from monogenic mutations can emerge during childhood or adulthood, and it is advisable to conduct genetic testing in cases in which there is a family history of chronic kidney disease, nephrotic syndrome, or resistance to treatment. Genome-wide association studies have identified several genetic risk variants, such as those in apolipoprotein L1 (APOL1), that play a role in the development of FSGS. Currently, no specific treatments have been approved to treat genetic FSGS; however, interventions targeting underlying cofactor deficiencies have shown potential in some cases. Furthermore, encouraging results have emerged from a phase 2 trial investigating inaxaplin, a novel small molecule APOL1 channel inhibitor, in APOL1-associated FSGS.
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Affiliation(s)
- Marco Bonilla
- Section of Nephrology, Department of Medicine, University of Chicago, Chicago, IL
| | - Orhan Efe
- Division of Nephrology, Massachusetts General Hospital, Boston, MA
- Harvard Medical School, Boston, MA
| | - Haresh Selvaskandan
- IgA Mayer Nephropathy Laboratories, Department of Cardiovascular Sciences, University of Leicester, Leicester, United Kingdom
- John Walls Renal Unit, University Hospitals of Leicester NHS Trust, Leicester, United Kingdom
| | - Edgar V. Lerma
- Section of Nephrology, University of Illinois at Chicago/Advocate Christ Medical Center, Oak Lawn, IL
| | - Nasim Wiegley
- University of California Davis School of Medicine, Division of Nephrology, Sacramento, CA
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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.
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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
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Xu C, Liu X, Zhai X, Wang G, Qin W, Cheng Z, Chen Z. CDDO-Me ameliorates podocyte injury through anti-oxidative stress and regulation of actin cytoskeleton in adriamycin nephropathy. Biomed Pharmacother 2023; 167:115617. [PMID: 37801905 DOI: 10.1016/j.biopha.2023.115617] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Revised: 09/27/2023] [Accepted: 09/28/2023] [Indexed: 10/08/2023] Open
Abstract
Podocyte injury is the common initiating event in focal segmental glomerulosclerosis (FSGS). Oxidative stress and inflammation mediate podocyte injury in FSGS. NRF2 pathway regulates the constitutive and inducible transcription of various genes that encode antioxidant proteins and anti-inflammatory proteins and have pivotal roles in the defense against cellular oxidative stress. In this study, we used adriamycin-induced nephropathy (ADR) in mice as a model of FSGS to confirm that CDDO-Me treatment ameliorated adriamycin-induced kidney damage by improving renal function and kidney histology. CDDO-Me inhibited the level of oxidative stress, inflammation, and apoptosis in adriamycin-induced podocyte injury by activating NRF2 pathway in vivo and in vitro. Furthermore, CDDO-Me stabled the cytoskeleton by regulating NRF2/srGAP2a pathway. Together, these findings show that by activating NRF2 pathway, CDDO-Me could be a therapeutic strategy to prevent the adverse effects of adriamycin-induced podocyte injury.
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Affiliation(s)
- Cheng Xu
- National Clinical Research Center of Kidney Diseases, Jinling Hospital, Nanjing University School of Medicine, Nanjing, China; Department of Nephrology, The Second Hospital of Jilin University, Nanguan District, Changchun 130041, Jilin, China
| | - Xing Liu
- National Clinical Research Center of Kidney Diseases, Jinling Hospital, Nanjing University School of Medicine, Nanjing, China
| | - Xiuwen Zhai
- National Clinical Research Center of Kidney Diseases, Jinling Hospital, Nanjing University School of Medicine, Nanjing, China
| | - Gang Wang
- National Clinical Research Center of Kidney Diseases, Jinling Hospital, Nanjing University School of Medicine, Nanjing, China
| | - Weisong Qin
- National Clinical Research Center of Kidney Diseases, Jinling Hospital, Nanjing University School of Medicine, Nanjing, China
| | - Zheng Cheng
- National Clinical Research Center of Kidney Diseases, Jinling Hospital, Nanjing University School of Medicine, Nanjing, China.
| | - Zhaohong Chen
- National Clinical Research Center of Kidney Diseases, Jinling Hospital, Nanjing University School of Medicine, Nanjing, China.
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Al Riyami MS, Al Alawi I, Al Gaithi B, Al Maskari A, Al Kalbani N, Al Hashmi N, Al Balushi A, Al Shahi M, Al Saidi S, Al Bimani M, Al Hatali F, Mabillard H, Sayer JA. Genetic analysis and outcomes of Omani children with steroid-resistant nephrotic syndrome. Mol Genet Genomic Med 2023; 11:e2201. [PMID: 37204080 PMCID: PMC10496054 DOI: 10.1002/mgg3.2201] [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: 02/11/2023] [Revised: 04/28/2023] [Accepted: 05/04/2023] [Indexed: 05/20/2023] Open
Abstract
BACKGROUND Nephrotic syndrome (NS) is one of the most common kidney disorders seen by pediatric nephrologists and is defined by the presence of heavy proteinuria (>3.5 g/24 h), hypoalbuminemia (<3.5 g/dL), edema, and hyperlipidemia. Most children with NS are steroid-responsive and have a good prognosis following treatment with prednisolone. However, 10%-20% of them have steroid-resistant nephrotic syndrome (SRNS) and fail to respond to treatment. A significant proportion of these children progress to kidney failure. METHODS This retrospective study aimed to determine the underlying genetic causes of SRNS among Omani children below 13 years old, over a 15-year period and included 77 children from 50 different families. We used targeted Sanger sequencing combined with next-generation sequencing approaches to perform molecular diagnostics. RESULTS We found a high rate of underlying genetic causes of SRNS in 61 (79.2%) children with pathogenic variants in the associated genes. Most of these genetically solved SRNS patients were born to consanguineous parents and variants were in the homozygous state. Pathogenic variants in NPHS2 were the most common cause of SRNS in our study seen in 37 (48.05%) cases. Pathogenic variants in NPHS1 were also seen in 16 cases, especially in infants with congenital nephrotic syndrome (CNS). Other genetic causes identified included pathogenic variants in LAMB2, PLCE1, MYO1E, and NUP93. CONCLUSION NPHS2 and NPHS1 genetic variants were the most common inherited causes of SRNS in Omani children. However, patients with variants in several other SRNS causative genes were also identified. We recommend screening for all genes responsible for SRNS in all children who present with this phenotype, which will assist in clinical management decisions and genetic counseling for the affected families.
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Affiliation(s)
| | - Intisar Al Alawi
- Translational and Clinical Research Institute, Faculty of Medical ScienceNewcastle UniversityNewcastle upon TyneUK
- National Genetic Center, Ministry of HealthMuscatOman
| | - Badria Al Gaithi
- Pediatric Nephrology Unit, Department of Child HealthyRoyal HospitalMuscatOman
| | - Anisa Al Maskari
- Pediatric Nephrology Unit, Department of Child HealthyRoyal HospitalMuscatOman
| | - Naifain Al Kalbani
- Pediatric Nephrology Unit, Department of Child HealthyRoyal HospitalMuscatOman
| | - Nadia Al Hashmi
- Pediatric Metabolic and Genetic Disorder UnitRoyal HospitalMuscatOman
| | - Aisha Al Balushi
- Pediatric Metabolic and Genetic Disorder UnitRoyal HospitalMuscatOman
| | - Maryam Al Shahi
- Pediatric Clinical Genetic Unit, Royal Hospital, Department of Child HealthRoyal HospitalMuscatOman
| | - Suliman Al Saidi
- Pediatric Nephrology Unit, Department of Child HealthyRoyal HospitalMuscatOman
| | | | | | - Holly Mabillard
- Translational and Clinical Research Institute, Faculty of Medical ScienceNewcastle UniversityNewcastle upon TyneUK
- Renal ServicesThe Newcastle upon Tyne Hospitals NHS Foundation TrustNewcastle upon TyneUK
- Newcastle Biomedical Research Center, NIHRNewcastle upon TyneUK
| | - John A. Sayer
- Translational and Clinical Research Institute, Faculty of Medical ScienceNewcastle UniversityNewcastle upon TyneUK
- Renal ServicesThe Newcastle upon Tyne Hospitals NHS Foundation TrustNewcastle upon TyneUK
- Newcastle Biomedical Research Center, NIHRNewcastle upon TyneUK
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Liu S, Liu P, Fei X, Zhu C, Hou J, Wang X, Pan Y. Analysis and validation of the potential of the MYO1E gene in pancreatic adenocarcinoma based on a bioinformatics approach. Oncol Lett 2023; 26:285. [PMID: 37274465 PMCID: PMC10236097 DOI: 10.3892/ol.2023.13871] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2023] [Accepted: 03/22/2023] [Indexed: 06/06/2023] Open
Abstract
Pancreatic adenocarcinoma (PAAD) is a common digestive cancer, and its prognosis is poor. Myosin 1E (MYO1E) is a class I myosin family member whose expression and function have not been reported in PAAD. In the present study, bioinformatics analysis was used to explore the expression levels of MYO1E in PAAD and its prognostic value, and the immunological role of MYO1E in PAAD was analyzed. The study revealed that a variety of malignancies have substantially increased MYO1E expression. Further investigation demonstrated that PAAD tissues exhibited greater levels of MYO1E mRNA and protein expression than normal tissues. High MYO1E expression is associated with poor prognosis in patients with PAAD. MYO1E expression was also associated with pathological stage in patients with PAAD. Functional enrichment analysis demonstrated that MYO1E was linked to multiple tumor-related mechanisms in PAAD. The pancreatic adenocarcinoma tumor microenvironment (TME) was analyzed and it was revealed that MYO1E expression was positively associated with tumor immune cell infiltration. In addition, MYO1E was closely associated with some tumor chemokines/receptors and immune checkpoints. In vitro experiments revealed that the suppression of MYO1E expression could inhibit pancreatic adenocarcinoma cell proliferation, invasion and migration. Through preliminary analysis, the present study evaluated the potential function of MYO1E in PAAD and its function in TME, and MYO1E may become a potential biomarker for PAAD.
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Affiliation(s)
- Songbai Liu
- School of Clinical Medicine, Guizhou Medical University, Guiyang, Guizhou 550000, P.R. China
| | - Peng Liu
- School of Clinical Medicine, Guizhou Medical University, Guiyang, Guizhou 550000, P.R. China
- Department of Hepatobiliary Surgery, The Affiliated Hospital of Guizhou Medical University, Guiyang, Guizhou 550000, P.R. China
| | - Xiaobin Fei
- School of Clinical Medicine, Guizhou Medical University, Guiyang, Guizhou 550000, P.R. China
| | - Changhao Zhu
- Department of Hepatobiliary Surgery, The Affiliated Cancer Hospital of Guizhou Medical University, Guiyang, Guizhou 550000, P.R. China
| | - Junyi Hou
- School of Clinical Medicine, Guizhou Medical University, Guiyang, Guizhou 550000, P.R. China
| | - Xing Wang
- School of Clinical Medicine, Guizhou Medical University, Guiyang, Guizhou 550000, P.R. China
- Department of Hepatobiliary Surgery, The Affiliated Cancer Hospital of Guizhou Medical University, Guiyang, Guizhou 550000, P.R. China
| | - Yaozhen Pan
- School of Clinical Medicine, Guizhou Medical University, Guiyang, Guizhou 550000, P.R. China
- Department of Hepatobiliary Surgery, The Affiliated Cancer Hospital of Guizhou Medical University, Guiyang, Guizhou 550000, P.R. China
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Krendel M, Leh S, Garone ME, Edwards-Richards A, Lin JJ, Brackman D, Knappskog P, Mikhailov A. Focal segmental glomerulosclerosis and proteinuria associated with Myo1E mutations: novel variants and histological phenotype analysis. Pediatr Nephrol 2023; 38:439-449. [PMID: 35723736 PMCID: PMC10506584 DOI: 10.1007/s00467-022-05634-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/28/2021] [Revised: 05/08/2022] [Accepted: 05/11/2022] [Indexed: 01/10/2023]
Abstract
BACKGROUND Pathogenic mutations in the non-muscle single-headed myosin, myosin 1E (Myo1e), are a rare cause of pediatric focal segmental glomerulosclerosis (FSGS). These mutations are biallelic, to date only reported as homozygous variants in consanguineous families. Myo1e regulates the actin cytoskeleton dynamics and cell adhesion, which are especially important for podocyte functions. METHODS DNA and RNA sequencing were used to identify novel MYO1E variants associated with FSGS. We studied the effects of these variants on the localization of Myo1e in kidney sections. We then analyzed the clinical and histological observations of all known pathogenic MYO1E variants. RESULTS We identified a patient compound heterozygote for two novel variants in MYO1E and a patient homozygous for a deletion of exon 19. Computer modeling predicted these variants to be disruptive. In both patients, Myo1e was mislocalized. As a rule, pathogenic MYO1E variants map to the Myo1e motor and neck domain and are most often associated with steroid-resistant nephrotic syndrome in children 1-11 years of age, leading to kidney failure in 4-10 years in a subset of patients. The ultrastructural features are the podocyte damage and striking diffuse and global Alport-like glomerular basement membrane (GBM) abnormalities. CONCLUSIONS We hypothesize that MYO1E mutations lead to disruption of the function of podocyte contractile actin cables resulting in abnormalities of the podocytes and the GBM and dysfunction of the glomerular filtration barrier. The characteristic clinicopathological data can help to tentatively differentiate this condition from other genetic podocytopathies and Alport syndrome until genetic testing is done. A higher resolution version of the Graphical abstract is available as Supplementary information.
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Affiliation(s)
- Mira Krendel
- Department of Cell and Developmental Biology, SUNY Upstate Medical University, Syracuse, NY, USA
| | - Sabine Leh
- Department of Pathology, Haukeland University Hospital, Bergen, Norway
- Department of Clinical Medicine, University of Bergen, Bergen, Norway
| | - Michael E Garone
- Department of Cell and Developmental Biology, SUNY Upstate Medical University, Syracuse, NY, USA
| | | | - Jen-Jar Lin
- Department of Pediatrics, Wake Forest Baptist Medical Center, Winston-Salem, NC, USA
| | - Damien Brackman
- Department of Pediatrics, Haukeland University Hospital, Bergen, Norway
| | - Per Knappskog
- Department of Clinical Science, University of Bergen, Bergen, Norway
- Department of Medical Genetics, Haukeland University Hospital, Bergen, Norway
| | - Alexei Mikhailov
- Department of Pathology, Atrium Health Wake Forest Baptist Medical Center, Winston-Salem, NC, USA.
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Li R, Dong W, Chen Y, Tang T, Zhao X, Zhang L, Liang X. Effect of cyclosporine A on focal segmental glomerulosclerosis caused by MYO1E mutation in a Chinese adult patient: A case report. Medicine (Baltimore) 2023; 102:e32683. [PMID: 36705362 PMCID: PMC9875993 DOI: 10.1097/md.0000000000032683] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
RATIONALE Focal segmental glomerulosclerosis (FSGS) describes a renal histologic lesion with diverse causes and pathogenicities. Monogenic abnormalities which are associated with impaired function of podocyte could result in FSGS. Most of genetic FSGS do not respond to immunosuppressive agents and often develop end-stage kidney disease. We reported a case of FSGS caused by myosin1e (MYO1E) mutation, alleviated by cyclosporine A (CsA) and low-dose glucocorticoid. PATIENT CONCERNS The patient was a 38-year-old male with nephrotic range proteinuria. He didn't respond to prednisone 65mg/day. Kidney biopsy in our hospital showed FSGS with several hypoplasia and tiny loops. In addition, focal thickening and disorganization of the glomerular gasement membrane as well as diffuse foot process effacement were observed in electron microscope. DIAGNOSES Genetic testing indicated homozygous deletion mutation of MYO1E. The patient was diagnosed with genetic FSGS caused by MYO1E homozygous mutation. INTERVENTIONS The patient was treated with CsA 50mg twice a day and low-dose methylprednisolone. OUTCOMES CsA and low-dose glucocorticoid dramatically reduced proteinuria, and partial remission was attained in 3 years follow-up. LESSONS MYO1E autosomal recessive mutation was a rare FSGS causative mutation that might benefit from CsA treatment. However, the long-term effect of CsA on FSGS caused by this mutation should be investigated in the future.
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Affiliation(s)
- Ruizhao Li
- Department of Nephrology, Guangdong Provincial People's Hospital (Guangdong Academy of Medical Sciences), Southern Medical University, Guangzhou, Guangdong, China
- Guangdong Cardiovascular Institute, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, Guangdong, China
| | - Wei Dong
- Department of Nephrology, Guangdong Provincial People's Hospital (Guangdong Academy of Medical Sciences), Southern Medical University, Guangzhou, Guangdong, China
| | - Yingwen Chen
- School of Medicine, South China University of Technology, Guangzhou, China
| | - Tianwei Tang
- Guangdong Cardiovascular Institute, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, Guangdong, China
| | - Xingchen Zhao
- Department of Nephrology, Guangdong Provincial People's Hospital (Guangdong Academy of Medical Sciences), Southern Medical University, Guangzhou, Guangdong, China
| | - Li Zhang
- Department of Nephrology, Guangdong Provincial People's Hospital (Guangdong Academy of Medical Sciences), Southern Medical University, Guangzhou, Guangdong, China
| | - Xinling Liang
- Department of Nephrology, Guangdong Provincial People's Hospital (Guangdong Academy of Medical Sciences), Southern Medical University, Guangzhou, Guangdong, China
- * Correspondence: Xinling Liang, Department of Nephrology, Guangdong Provincial People's Hospital (Guangdong Academy of Medical Sciences), Southern Medical University, Guangzhou 510080, China (e-mail: )
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Johnson CA, Behbehani R, Buss F. Unconventional Myosins from Caenorhabditis elegans as a Probe to Study Human Orthologues. Biomolecules 2022; 12:biom12121889. [PMID: 36551317 PMCID: PMC9775386 DOI: 10.3390/biom12121889] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Revised: 12/09/2022] [Accepted: 12/13/2022] [Indexed: 12/23/2022] Open
Abstract
Unconventional myosins are a superfamily of actin-based motor proteins that perform a number of roles in fundamental cellular processes, including (but not limited to) intracellular trafficking, cell motility, endocytosis, exocytosis and cytokinesis. 40 myosins genes have been identified in humans, which belong to different 12 classes based on their domain structure and organisation. These genes are widely expressed in different tissues, and mutations leading to loss of function are associated with a wide variety of pathologies while over-expression often results in cancer. Caenorhabditis elegans (C. elegans) is a small, free-living, non-parasitic nematode. ~38% of the genome of C. elegans has predicted orthologues in the human genome, making it a valuable tool to study the function of human counterparts and human diseases. To date, 8 unconventional myosin genes have been identified in the nematode, from 6 different classes with high homology to human paralogues. The hum-1 and hum-5 (heavy chain of an unconventional myosin) genes encode myosin of class I, hum-2 of class V, hum-3 and hum-8 of class VI, hum-6 of class VII and hum-7 of class IX. The hum-4 gene encodes a high molecular mass myosin (307 kDa) that is one of the most highly divergent myosins and is a member of class XII. Mutations in many of the human orthologues are lethal, indicating their essential properties. However, a functional characterisation for many of these genes in C. elegans has not yet been performed. This article reviews the current knowledge of unconventional myosin genes in C. elegans and explores the potential use of the nematode to study the function and regulation of myosin motors to provide valuable insights into their role in diseases.
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Ahmadian E, Eftekhari A, Atakishizada S, Valiyeva M, Ardalan M, Khalilov R, Kavetskyy T. Podocytopathy: The role of actin cytoskeleton. Biomed Pharmacother 2022; 156:113920. [DOI: 10.1016/j.biopha.2022.113920] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2022] [Revised: 10/12/2022] [Accepted: 10/24/2022] [Indexed: 11/02/2022] Open
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Liu PJ, Gunther LK, Garone ME, Zhang C, Perez D, Bi-Karchin J, Pellenz CD, Chase SE, Presti MF, Plante EL, Martin CE, Lovric S, Yengo CM, Hildebrandt F, Krendel M. Steroid-Resistant Nephrotic Syndrome-Associated MYO1E Mutations Have Differential Effects on Myosin 1e Localization, Dynamics, and Activity. J Am Soc Nephrol 2022; 33:1989-2007. [PMID: 36316095 PMCID: PMC9678034 DOI: 10.1681/asn.2021111505] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Accepted: 08/22/2022] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND Myo1e is a nonmuscle motor protein enriched in podocytes. Mutations in MYO1E are associated with steroid-resistant nephrotic syndrome (SRNS). Most of the MYO1E variants identified by genomic sequencing have not been functionally characterized. Here, we set out to analyze two mutations in the Myo1e motor domain, T119I and D388H, which were selected on the basis of protein sequence conservation. METHODS EGFP-tagged human Myo1e constructs were delivered into the Myo1e-KO mouse podocyte-derived cells via adenoviral infection to analyze Myo1e protein stability, Myo1e localization, and clathrin-dependent endocytosis, which is known to involve Myo1e activity. Furthermore, truncated Myo1e constructs were expressed using the baculovirus expression system and used to measure Myo1e ATPase and motor activity in vitro. RESULTS Both mutants were expressed as full-length proteins in the Myo1e-KO cells. However, unlike wild-type (WT) Myo1e, the T119I variant was not enriched at the cell junctions or clathrin-coated vesicles (CCVs). In contrast, D388H variant localization was similar to that of WT. The rate of dissociation of the D388H variant from cell-cell junctions and CCVs was decreased, suggesting this mutation affects Myo1e interactions with binding partners. ATPase activity and ability to translocate actin filaments were drastically reduced for the D388H mutant, supporting findings from cell-based experiments. CONCLUSIONS T119I and D388H mutations are deleterious to Myo1e functions. The experimental approaches used in this study can be applied to future characterization of novel MYO1E variants associated with SRNS.
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Affiliation(s)
- Pei-Ju Liu
- Department of Cell and Developmental Biology, State University of New York Upstate Medical University, Syracuse, New York
| | - Laura K. Gunther
- Department of Cellular and Molecular Physiology, College of Medicine, Pennsylvania State University, Hershey, Pennsylvania
| | - Michael E. Garone
- Department of Cell and Developmental Biology, State University of New York Upstate Medical University, Syracuse, New York
| | - Chunling Zhang
- Department of Neuroscience and Physiology, State University of New York Upstate Medical University, Syracuse, New York
| | - Diana Perez
- Department of Cell and Developmental Biology, State University of New York Upstate Medical University, Syracuse, New York
| | - Jing Bi-Karchin
- Department of Cell and Developmental Biology, State University of New York Upstate Medical University, Syracuse, New York
| | - Christopher D. Pellenz
- Department of Cell and Developmental Biology, State University of New York Upstate Medical University, Syracuse, New York
| | - Sharon E. Chase
- Department of Cell and Developmental Biology, State University of New York Upstate Medical University, Syracuse, New York
| | - Maria F. Presti
- Department of Cell and Developmental Biology, State University of New York Upstate Medical University, Syracuse, New York
| | - Eric L. Plante
- Department of Cell and Developmental Biology, State University of New York Upstate Medical University, Syracuse, New York
| | - Claire E. Martin
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Sinai Health System, Toronto, Ontario, Canada
| | - Svjetlana Lovric
- Divison of Nephrology, Department of Pediatrics, Boston Children’s Hospital, Harvard Medical School, Boston, Massachusetts
| | - Christopher M. Yengo
- Department of Cellular and Molecular Physiology, College of Medicine, Pennsylvania State University, Hershey, Pennsylvania
| | - Friedhelm Hildebrandt
- Divison of Nephrology, Department of Pediatrics, Boston Children’s Hospital, Harvard Medical School, Boston, Massachusetts
| | - Mira Krendel
- Department of Cell and Developmental Biology, State University of New York Upstate Medical University, Syracuse, New York
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12
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Sambharia M, Rastogi P, Thomas CP. Monogenic focal segmental glomerulosclerosis: A conceptual framework for identification and management of a heterogeneous disease. AMERICAN JOURNAL OF MEDICAL GENETICS. PART C, SEMINARS IN MEDICAL GENETICS 2022; 190:377-398. [PMID: 35894442 PMCID: PMC9796580 DOI: 10.1002/ajmg.c.31990] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Revised: 05/31/2022] [Accepted: 06/30/2022] [Indexed: 01/29/2023]
Abstract
Focal segmental glomerulosclerosis (FSGS) is not a disease, rather a pattern of histological injury occurring from a variety of causes. The exact pathogenesis has yet to be fully elucidated but is likely varied based on the type of injury and the primary target of that injury. However, the approach to treatment is often based on the degree of podocyte foot process effacement and clinical presentation without sufficient attention paid to etiology. In this regard, there are many monogenic causes of FSGS with variable presentation from nephrotic syndrome with histological features of primary podocytopathy to more modest degrees of proteinuria with limited evidence of podocyte foot process injury. It is likely that genetic causes are largely underdiagnosed, as the role and the timing of genetic testing in FSGS is not established and genetic counseling, testing options, and interpretation of genotype in the context of phenotype may be outside the scope of practice for both nephrologists and geneticists. Yet most clinicians believe that a genetic diagnosis can lead to targeted therapy, limit the use of high-dose corticosteroids as a therapeutic trial, and allow the prediction of the natural history and risk for recurrence in the transplanted kidney. In this manuscript, we emphasize that genetic FSGS is not monolithic in its presentation, opine on the importance of genetic testing and provide an algorithmic approach to deployment of genetic testing in a timely fashion when faced with a patient with FSGS.
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Affiliation(s)
- Meenakshi Sambharia
- Division of Nephrology, Department of Internal MedicineUniversity of IowaIowa CityIowaUSA
| | - Prerna Rastogi
- Department of PathologyUniversity of IowaIowa CityIowaUSA
| | - Christie P. Thomas
- Division of Nephrology, Department of Internal MedicineUniversity of IowaIowa CityIowaUSA,Department of PediatricsUniversity of IowaIowa CityIowaUSA,The Iowa Institute of Human GeneticsUniversity of IowaIowa CityIowaUSA,Medical ServiceVeterans Affairs Medical CenterIowa CityIowaUSA
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13
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Pernier J, Schauer K. Does the Actin Network Architecture Leverage Myosin-I Functions? BIOLOGY 2022; 11:biology11070989. [PMID: 36101369 PMCID: PMC9311500 DOI: 10.3390/biology11070989] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/19/2022] [Revised: 06/24/2022] [Accepted: 06/26/2022] [Indexed: 11/16/2022]
Abstract
The actin cytoskeleton plays crucial roles in cell morphogenesis and functions. The main partners of cortical actin are molecular motors of the myosin superfamily. Although our understanding of myosin functions is heavily based on myosin-II and its ability to dimerize, the largest and most ancient class is represented by myosin-I. Class 1 myosins are monomeric, actin-based motors that regulate a wide spectrum of functions, and whose dysregulation mediates multiple human diseases. We highlight the current challenges in identifying the “pantograph” for myosin-I motors: we need to reveal how conformational changes of myosin-I motors lead to diverse cellular as well as multicellular phenotypes. We review several mechanisms for scaling, and focus on the (re-) emerging function of class 1 myosins to remodel the actin network architecture, a higher-order dynamic scaffold that has potential to leverage molecular myosin-I functions. Undoubtfully, understanding the molecular functions of myosin-I motors will reveal unexpected stories about its big partner, the dynamic actin cytoskeleton.
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Affiliation(s)
- Julien Pernier
- Institute for Integrative Biology of the Cell (I2BC), Centre National de la Recherche Scientifique (CNRS), Commissariat à L’Énergie Atomique et aux Énergies Alternatives (CEA), Université Paris-Saclay, 91198 Gif-sur-Yvette, France;
| | - Kristine Schauer
- Tumor Cell Dynamics Unit, Inserm U1279, Gustave Roussy Institute, Université Paris-Saclay, 94800 Villejuif, France
- Correspondence:
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14
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Grossman OK, Schretlen CF, Nield LS. Concordant nephrotic syndrome in twins with PAX2 and MYO1E mutations. Clin Nephrol Case Stud 2022; 10:37-41. [PMID: 35574290 PMCID: PMC9097507 DOI: 10.5414/cncs110799] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Accepted: 03/07/2022] [Indexed: 11/20/2022] Open
Abstract
INTRODUCTION The medical literature is scant with reports of twins diagnosed with nephrotic syndrome associated with genetic mutations. Mutations in the protein coding paired box gene 2 (PAX2) and in the non-muscle class I myosin, myosin 1E, (MYO1E) have been implicated in the development of steroid-resistant nephrotic syndrome. We describe the first case, to our knowledge, of the concordant presentation of nephrotic syndrome in twins with simultaneous mutations in PAX2 and MYO1E. CASE REPORT At 32 months and 33 months of age, monochorionic, diamniotic twin girls presented with nephrotic syndrome. Each twin experienced three relapses during or after completion of corticosteroid treatment. Sustained remission was achieved with tacrolimus. Genetic testing of each twin revealed two heterozygous mutations of MYO1E and one homozygous mutation of PAX2. Renal biopsy results of one twin revealed pathologic findings consistent with minimal change nephropathy. The twins' phenotypes have been essentially identical. CONCLUSION Our cases add to the scant medical literature addressing nephrotic syndrome in twins with genetic mutations. Close monitoring of our unique patients will provide novel information about the clinical significance of combined mutations in PAX2 and MYO1E.
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Affiliation(s)
- Oulimata K Grossman
- Department of Pediatrics West Virginia University School of Medicine, Children's Hospital Morgantown, WV, and
| | - Claire F Schretlen
- Division of Nephrology, Nephrology Fellowship Program Johns Hopkins University School of Medicine Baltimore, MD, USA
| | - Linda S Nield
- Department of Pediatrics West Virginia University School of Medicine, Children's Hospital Morgantown, WV, and
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15
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Radhakrishnan R, Dronamraju VR, Leung M, Gruesen A, Solanki AK, Walterhouse S, Roehrich H, Song G, da Costa Monsanto R, Cureoglu S, Martin R, Kondkar AA, van Kuijk FJ, Montezuma SR, Knöelker HJ, Hufnagel RB, Lobo GP. The role of motor proteins in photoreceptor protein transport and visual function. Ophthalmic Genet 2022; 43:285-300. [PMID: 35470760 DOI: 10.1080/13816810.2022.2062391] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
BACKGROUND Rods and cones are photoreceptor neurons in the retina that are required for visual sensation in vertebrates, wherein the perception of vision is initiated when these neurons respond to photons in the light stimuli. The photoreceptor cell is structurally studied as outer segments (OS) and inner segments (IS) where proper protein sorting, localization, and compartmentalization are critical for phototransduction, visual function, and survival. In human retinal diseases, improper protein transport to the OS or mislocalization of proteins to the IS and other cellular compartments could lead to impaired visual responses and photoreceptor cell degeneration that ultimately cause loss of visual function. RESULTS Therefore, studying and identifying mechanisms involved in facilitating and maintaining proper protein transport in photoreceptor cells would help our understanding of pathologies involving retinal cell degeneration in inherited retinal dystrophies, age-related macular degeneration, and Usher Syndrome. CONCLUSIONS Our mini-review will discuss mechanisms of protein transport within photoreceptors and introduce a novel role for an unconventional motor protein, MYO1C, in actin-based motor transport of the visual chromophore Rhodopsin to the OS, in support of phototransduction and visual function.
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Affiliation(s)
- Rakesh Radhakrishnan
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, Minneapolis, Minnesota, USA
| | - Venkateshwara R Dronamraju
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, Minneapolis, Minnesota, USA
| | - Matthias Leung
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, Minneapolis, Minnesota, USA
| | - Andrew Gruesen
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, Minneapolis, Minnesota, USA
| | - Ashish K Solanki
- Department of Medicine, Drug Discovery Building, Medical University of South Carolina, South Carolina, USA
| | - Stephen Walterhouse
- Department of Medicine, Drug Discovery Building, Medical University of South Carolina, South Carolina, USA
| | - Heidi Roehrich
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, Minneapolis, Minnesota, USA
| | - Grace Song
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, Minneapolis, Minnesota, USA
| | - Rafael da Costa Monsanto
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, Minneapolis, Minnesota, USA
| | - Sebahattin Cureoglu
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, Minneapolis, Minnesota, USA
| | - René Martin
- Faculty of Chemistry, Technische Universität Dresden, Dresden, Germany
| | - Altaf A Kondkar
- Department of Ophthalmology.,Glaucoma Research Chair in Ophthalmology, College of Medicine, King Saud University, Riyadh, Saudi Arabia
| | - Frederik J van Kuijk
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, Minneapolis, Minnesota, USA
| | - Sandra R Montezuma
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, Minneapolis, Minnesota, USA
| | | | - Robert B Hufnagel
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Glenn P Lobo
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, Minneapolis, Minnesota, USA.,Department of Medicine, Drug Discovery Building, Medical University of South Carolina, South Carolina, USA.,Department of Ophthalmology, Medical University of South Carolina, South Carolina, USA
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16
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Mechanisms of podocyte injury and implications for diabetic nephropathy. Clin Sci (Lond) 2022; 136:493-520. [PMID: 35415751 PMCID: PMC9008595 DOI: 10.1042/cs20210625] [Citation(s) in RCA: 47] [Impact Index Per Article: 23.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2021] [Revised: 02/25/2022] [Accepted: 03/25/2022] [Indexed: 02/06/2023]
Abstract
Albuminuria is the hallmark of both primary and secondary proteinuric glomerulopathies, including focal segmental glomerulosclerosis (FSGS), obesity-related nephropathy, and diabetic nephropathy (DN). Moreover, albuminuria is an important feature of all chronic kidney diseases (CKDs). Podocytes play a key role in maintaining the permselectivity of the glomerular filtration barrier (GFB) and injury of the podocyte, leading to foot process (FP) effacement and podocyte loss, the unifying underlying mechanism of proteinuric glomerulopathies. The metabolic insult of hyperglycemia is of paramount importance in the pathogenesis of DN, while insults leading to podocyte damage are poorly defined in other proteinuric glomerulopathies. However, shared mechanisms of podocyte damage have been identified. Herein, we will review the role of haemodynamic and oxidative stress, inflammation, lipotoxicity, endocannabinoid (EC) hypertone, and both mitochondrial and autophagic dysfunction in the pathogenesis of the podocyte damage, focussing particularly on their role in the pathogenesis of DN. Gaining a better insight into the mechanisms of podocyte injury may provide novel targets for treatment. Moreover, novel strategies for boosting podocyte repair may open the way to podocyte regenerative medicine.
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17
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van de Leemput J, Wen P, Han Z. Using Drosophila Nephrocytes to Understand the Formation and Maintenance of the Podocyte Slit Diaphragm. Front Cell Dev Biol 2022; 10:837828. [PMID: 35265622 PMCID: PMC8898902 DOI: 10.3389/fcell.2022.837828] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Accepted: 02/01/2022] [Indexed: 12/12/2022] Open
Abstract
The podocyte slit diaphragm (SD) is an essential component of the glomerular filtration barrier and its disruption is a common cause of proteinuria and many types of kidney disease. Therefore, better understanding of the pathways and proteins that play key roles in SD formation and maintenance has been of great interest. Podocyte and SD biology have been mainly studied using mouse and other vertebrate models. However, vertebrates are limited by inherent properties and technically challenging in vivo access to the podocytes. Drosophila is a relatively new alternative model system but it has already made great strides. Past the initial obvious differences, mammalian podocytes and fly nephrocytes are remarkably similar at the genetic, molecular and functional levels. This review discusses SD formation and maintenance, and their dependence on cell polarity, the cytoskeleton, and endo- and exocytosis, as learned from studies in fly nephrocytes and mammalian podocytes. In addition, it reflects on the remaining gaps in our knowledge, the physiological implications for glomerular diseases and how we can leverage the advantages Drosophila has to offer to further our understanding.
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Affiliation(s)
- Joyce van de Leemput
- Center for Precision Disease Modeling, Department of Medicine, University of Maryland School of Medicine, Baltimore, MD, United States.,Division of Endocrinology, Diabetes and Nutrition, Department of Medicine, University of Maryland School of Medicine, Baltimore, MD, United States
| | - Pei Wen
- Center for Precision Disease Modeling, Department of Medicine, University of Maryland School of Medicine, Baltimore, MD, United States.,Division of Endocrinology, Diabetes and Nutrition, Department of Medicine, University of Maryland School of Medicine, Baltimore, MD, United States
| | - Zhe Han
- Center for Precision Disease Modeling, Department of Medicine, University of Maryland School of Medicine, Baltimore, MD, United States.,Division of Endocrinology, Diabetes and Nutrition, Department of Medicine, University of Maryland School of Medicine, Baltimore, MD, United States
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18
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Liu M, Cardilla A, Ngeow J, Gong X, Xia Y. Studying Kidney Diseases Using Organoid Models. Front Cell Dev Biol 2022; 10:845401. [PMID: 35309912 PMCID: PMC8927804 DOI: 10.3389/fcell.2022.845401] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2021] [Accepted: 02/14/2022] [Indexed: 12/24/2022] Open
Abstract
The prevalence of chronic kidney disease (CKD) is rapidly increasing over the last few decades, owing to the global increase in diabetes, and cardiovascular diseases. Dialysis greatly compromises the life quality of patients, while demand for transplantable kidney cannot be met, underscoring the need to develop novel therapeutic approaches to stop or reverse CKD progression. Our understanding of kidney disease is primarily derived from studies using animal models and cell culture. While cross-species differences made it challenging to fully translate findings from animal models into clinical practice, primary patient cells quickly lose the original phenotypes during in vitro culture. Over the last decade, remarkable achievements have been made for generating 3-dimensional (3D) miniature organs (organoids) by exposing stem cells to culture conditions that mimic the signaling cues required for the development of a particular organ or tissue. 3D kidney organoids have been successfully generated from different types of source cells, including human pluripotent stem cells (hPSCs), adult/fetal renal tissues, and kidney cancer biopsy. Alongside gene editing tools, hPSC-derived kidney organoids are being harnessed to model genetic kidney diseases. In comparison, adult kidney-derived tubuloids and kidney cancer-derived tumoroids are still in their infancy. Herein, we first summarize the currently available kidney organoid models. Next, we discuss recent advances in kidney disease modelling using organoid models. Finally, we consider the major challenges that have hindered the application of kidney organoids in disease modelling and drug evaluation and propose prospective solutions.
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Affiliation(s)
- Meng Liu
- Lee Kong Chian School of Medicine, Nanyang Technological University Singapore, Singapore, Singapore
| | - Angelysia Cardilla
- Lee Kong Chian School of Medicine, Nanyang Technological University Singapore, Singapore, Singapore
| | - Joanne Ngeow
- Lee Kong Chian School of Medicine, Nanyang Technological University Singapore, Singapore, Singapore
- Cancer Genetics Service, National Cancer Centre Singapore, Singapore, Singapore
| | - Ximing Gong
- Lee Kong Chian School of Medicine, Nanyang Technological University Singapore, Singapore, Singapore
- *Correspondence: Ximing Gong, ; Yun Xia,
| | - Yun Xia
- Lee Kong Chian School of Medicine, Nanyang Technological University Singapore, Singapore, Singapore
- *Correspondence: Ximing Gong, ; Yun Xia,
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19
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Tian X, Bunda P, Ishibe S. Podocyte Endocytosis in Regulating the Glomerular Filtration Barrier. Front Med (Lausanne) 2022; 9:801837. [PMID: 35223901 PMCID: PMC8866310 DOI: 10.3389/fmed.2022.801837] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2021] [Accepted: 01/06/2022] [Indexed: 12/26/2022] Open
Abstract
Endocytosis is a mechanism that internalizes and recycles plasma membrane components and transmembrane receptors via vesicle formation, which is mediated by clathrin-dependent and clathrin-independent signaling pathways. Podocytes are specialized, terminally differentiated epithelial cells in the kidney, located on the outermost layer of the glomerulus. These cells play an important role in maintaining the integrity of the glomerular filtration barrier in conjunction with the adjacent basement membrane and endothelial cell layers within the glomerulus. An intact podocyte endocytic machinery appears to be necessary for maintaining podocyte function. De novo pathologic human genetic mutations and loss-of-function studies of critical podocyte endocytosis genes in genetically engineered mouse models suggest that this pathway contributes to the pathophysiology of development and progression of proteinuria in chronic kidney disease. Here, we review the mechanism of cellular endocytosis and its regulation in podocyte injury in the context of glomerular diseases. A thorough understanding of podocyte endocytosis may shed novel insights into its biological function in maintaining a functioning filter and offer potential targeted therapeutic strategies for proteinuric glomerular diseases.
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Affiliation(s)
- Xuefei Tian
- Department of Internal Medicine, Yale School of Medicine, New Haven, CT, United States
| | - Patricia Bunda
- Department of Internal Medicine, Yale School of Medicine, New Haven, CT, United States
| | - Shuta Ishibe
- Department of Internal Medicine, Yale School of Medicine, New Haven, CT, United States
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20
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Ding Y, Diao Z, Cui H, Yang A, Liu W, Jiang L. Bioinformatics analysis reveals the roles of cytoskeleton protein transgelin in occurrence and development of proteinuria. Transl Pediatr 2021; 10:2250-2268. [PMID: 34733666 PMCID: PMC8506063 DOI: 10.21037/tp-21-83] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Accepted: 07/15/2021] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND Proteinuria is a sensitive hallmark for progressive renal dysfunction. Transgelin (TAGLN) has been demonstrated to participate in etiology of proteinuria and dynamics of podocyte foot process; however, the mechanism of TAGLN involvement in proteinuria is unknown. The present study aimed to explore the roles of TAGLN in the development of proteinuria. METHODS Differentially expressed genes (DEGs) were detected from microarray expression profiling datasets from Gene Expression Omnibus, and analyzed by the short time series expression miner to cluster the DEGs in proteinuria progression. Kyoto Encyclopedia of Genes and Genomes pathway analysis was used to determine the top 20 enriched pathways, and construct a gene interaction network. RESULTS In total, 2,409 DEGs for nephropathy and 10,612 DEGs for podocyte foot process and proteinuria were detected. Additionally, 76 common DEGs (25 upregulated and 41 downregulated) between nephropathy and podocyte foot process were primarily involved in innate immunity, positive regulation of transcription-DNA-templated, immunity and negative regulation of cell proliferation, enriched in cytokine-cytokine receptor interaction signaling pathway, Ras signaling pathway, axon guidance, tumor necrosis factor (TNF) signaling pathway and apoptosis. CONCLUSIONS We discovered a TAGLN-mediated regulatory network involved in proteinuria progression. These findings provide novel insight to understand the molecular mechanisms underlying the pathogenesis of proteinuria.
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Affiliation(s)
- Yingxue Ding
- Pediatric Department, Beijing Friendship Hospital, Capital University of Medical Sciences, Beijing, China
| | - Zongli Diao
- Nephrology Department, Beijing Friendship Hospital, Capital University of Medical Sciences, Beijing, China
| | - Hong Cui
- Pediatric Department, Beijing Friendship Hospital, Capital University of Medical Sciences, Beijing, China
| | - Aijun Yang
- Pediatric Department, Beijing Friendship Hospital, Capital University of Medical Sciences, Beijing, China
| | - Wenhu Liu
- Nephrology Department, Beijing Friendship Hospital, Capital University of Medical Sciences, Beijing, China
| | - Lina Jiang
- Pediatric Department, Beijing Friendship Hospital, Capital University of Medical Sciences, Beijing, China
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21
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Sever S. Role of actin cytoskeleton in podocytes. Pediatr Nephrol 2021; 36:2607-2614. [PMID: 33188449 PMCID: PMC8116355 DOI: 10.1007/s00467-020-04812-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Revised: 09/14/2020] [Accepted: 10/05/2020] [Indexed: 12/11/2022]
Abstract
The selectivity of the glomerular filter is established by physical, chemical, and signaling interplay among its three core constituents: glomerular endothelial cells, the glomerular basement membrane, and podocytes. Functional impairment or injury of any of these three components can lead to proteinuria. Podocytes are injured in many forms of human and experimental glomerular disease, including minimal change disease, focal segmental glomerulosclerosis, and diabetes mellitus. One of the earliest signs of podocyte injury is loss of their distinct structure, which is driven by dysregulated dynamics of the actin cytoskeleton. The status of the actin cytoskeleton in podocytes depends on a set of actin binding proteins, nucleators and inhibitors of actin polymerization, and regulatory GTPases. Mutations that alter protein function in each category have been implicated in glomerular diseases in humans and animal models. In addition, a growing body of studies suggest that pharmacological modifications of the actin cytoskeleton have the potential to become novel therapeutics for podocyte-dependent chronic kidney diseases. This review presents an overview of the essential proteins that establish actin cytoskeleton in podocytes and studies demonstrating the feasibility of drugging actin cytoskeleton in kidney diseases.
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Affiliation(s)
- Sanja Sever
- Harvard Medical School and Massachusetts General Hospital, Boston, MA, USA.
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22
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Hearing Function: Identification of New Candidate Genes Further Explaining the Complexity of This Sensory Ability. Genes (Basel) 2021; 12:genes12081228. [PMID: 34440402 PMCID: PMC8394865 DOI: 10.3390/genes12081228] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Revised: 08/05/2021] [Accepted: 08/06/2021] [Indexed: 11/16/2022] Open
Abstract
To date, the knowledge of the genetic determinants behind the modulation of hearing ability is relatively limited. To investigate this trait, we performed Genome-Wide Association Study (GWAS) meta-analysis using genotype and audiometric data (hearing thresholds at 0.25, 0.5, 1, 2, 4, and 8 kHz, and pure-tone averages of thresholds at low, medium, and high frequencies) collected in nine cohorts from Europe, South-Eastern USA, Caucasus, and Central Asia, for an overall number of ~9000 subjects. Three hundred seventy-five genes across all nine analyses were tagged by single nucleotide polymorphisms (SNPs) reaching a suggestive p-value (p < 10−5). Amongst these, 15 were successfully replicated using a gene-based approach in the independent Italian Salus in the Apulia cohort (n = 1774) at the nominal significance threshold (p < 0.05). In addition, the expression level of the replicated genes was assessed in published human and mouse inner ear datasets. Considering expression patterns in humans and mice, eleven genes were considered particularly promising candidates for the hearing function: BNIP3L, ELP5, MAP3K20, MATN2, MTMR7, MYO1E, PCNT, R3HDM1, SLC9A9, TGFB2, and YTHDC2. These findings represent a further contribution to our understanding of the genetic basis of hearing function and its related diseases.
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23
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Daehn IS, Duffield JS. The glomerular filtration barrier: a structural target for novel kidney therapies. Nat Rev Drug Discov 2021; 20:770-788. [PMID: 34262140 PMCID: PMC8278373 DOI: 10.1038/s41573-021-00242-0] [Citation(s) in RCA: 86] [Impact Index Per Article: 28.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/28/2021] [Indexed: 12/19/2022]
Abstract
Loss of normal kidney function affects more than 10% of the population and contributes to morbidity and mortality. Kidney diseases are currently treated with immunosuppressive agents, antihypertensives and diuretics with partial but limited success. Most kidney disease is characterized by breakdown of the glomerular filtration barrier (GFB). Specialized podocyte cells maintain the GFB, and structure-function experiments and studies of intercellular communication between the podocytes and other GFB cells, combined with advances from genetics and genomics, have laid the groundwork for a new generation of therapies that directly intervene at the GFB. These include inhibitors of apolipoprotein L1 (APOL1), short transient receptor potential channels (TRPCs), soluble fms-like tyrosine kinase 1 (sFLT1; also known as soluble vascular endothelial growth factor receptor 1), roundabout homologue 2 (ROBO2), endothelin receptor A, soluble urokinase plasminogen activator surface receptor (suPAR) and substrate intermediates for coenzyme Q10 (CoQ10). These molecular targets converge on two key components of GFB biology: mitochondrial function and the actin-myosin contractile machinery. This Review discusses therapies and developments focused on maintaining GFB integrity, and the emerging questions in this evolving field.
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Affiliation(s)
- Ilse S Daehn
- Department of Medicine, Division of Nephrology, The Icahn School of Medicine at Mount Sinai, New York, NY, USA.
| | - Jeremy S Duffield
- Research and Development, Prime Medicine, Cambridge, MA, USA. .,Department of Medicine, University of Washington, Seattle, WA, USA. .,Department of Medicine, Massachusetts General Hospital, Boston, MA, USA.
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24
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Li Q, Veron D, Tufro A. S-Nitrosylation of RhoGAP Myosin9A Is Altered in Advanced Diabetic Kidney Disease. Front Med (Lausanne) 2021; 8:679518. [PMID: 34336885 PMCID: PMC8316719 DOI: 10.3389/fmed.2021.679518] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Accepted: 06/18/2021] [Indexed: 12/13/2022] Open
Abstract
The molecular pathogenesis of diabetic kidney disease progression is complex and remains unresolved. Rho-GAP MYO9A was recently identified as a novel podocyte protein and a candidate gene for monogenic FSGS. Myo9A involvement in diabetic kidney disease has been suggested. Here, we examined the effect of diabetic milieu on Myo9A expression in vivo and in vitro. We determined that Myo9A undergoes S-nitrosylation, a post-translational modification dependent on nitric oxide (NO) availability. Diabetic mice with nodular glomerulosclerosis and severe proteinuria associated with doxycycline-induced, podocyte-specific VEGF 164 gain-of-function showed markedly decreased glomerular Myo9A expression and S-nitrosylation, as compared to uninduced diabetic mice. Immortalized mouse podocytes exposed to high glucose revealed decreased Myo9A expression, assessed by qPCR, immunoblot and immunocytochemistry, and reduced Myo9A S-nitrosylation (SNO-Myo9A), assessed by proximity link assay and biotin switch test, functionally resulting in abnormal podocyte migration. These defects were abrogated by exposure to a NO donor and were not due to hyperosmolarity. Our data demonstrate that high-glucose induced decrease of both Myo9A expression and SNO-Myo9A is regulated by NO availability. We detected S-nitrosylation of Myo9A interacting proteins RhoA and actin, which was also altered by high glucose and NO dependent. RhoA activity inversely related to SNO-RhoA. Collectively, data suggest that dysregulation of SNO-Myo9A, SNO-RhoA and SNO-actin may contribute to the pathogenesis of advanced diabetic kidney disease and may be amenable to therapeutic targeting.
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Affiliation(s)
- Qi Li
- Department of Pediatrics/Nephrology, New Haven, CT, United States
| | - Delma Veron
- Department of Pediatrics/Nephrology, New Haven, CT, United States
| | - Alda Tufro
- Department of Pediatrics/Nephrology, New Haven, CT, United States.,Department of Cell and Molecular Physiology, Yale School of Medicine, New Haven, CT, United States
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Bondue T, Arcolino FO, Veys KRP, Adebayo OC, Levtchenko E, van den Heuvel LP, Elmonem MA. Urine-Derived Epithelial Cells as Models for Genetic Kidney Diseases. Cells 2021; 10:cells10061413. [PMID: 34204173 PMCID: PMC8230018 DOI: 10.3390/cells10061413] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Revised: 05/28/2021] [Accepted: 06/02/2021] [Indexed: 12/11/2022] Open
Abstract
Epithelial cells exfoliated in human urine can include cells anywhere from the urinary tract and kidneys; however, podocytes and proximal tubular epithelial cells (PTECs) are by far the most relevant cell types for the study of genetic kidney diseases. When maintained in vitro, they have been proven extremely valuable for discovering disease mechanisms and for the development of new therapies. Furthermore, cultured patient cells can individually represent their human sources and their specific variants for personalized medicine studies, which are recently gaining much interest. In this review, we summarize the methodology for establishing human podocyte and PTEC cell lines from urine and highlight their importance as kidney disease cell models. We explore the well-established and recent techniques of cell isolation, quantification, immortalization and characterization, and we describe their current and future applications.
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Affiliation(s)
- Tjessa Bondue
- Department of Development and Regeneration, KU Leuven, 3000 Leuven, Belgium; (T.B.); (F.O.A.); (K.R.P.V.); (O.C.A.); (E.L.); (L.P.v.d.H.)
| | - Fanny O. Arcolino
- Department of Development and Regeneration, KU Leuven, 3000 Leuven, Belgium; (T.B.); (F.O.A.); (K.R.P.V.); (O.C.A.); (E.L.); (L.P.v.d.H.)
| | - Koenraad R. P. Veys
- Department of Development and Regeneration, KU Leuven, 3000 Leuven, Belgium; (T.B.); (F.O.A.); (K.R.P.V.); (O.C.A.); (E.L.); (L.P.v.d.H.)
- Department of Pediatrics, Division of Pediatric Nephrology, University Hospitals Leuven, 3000 Leuven, Belgium
| | - Oyindamola C. Adebayo
- Department of Development and Regeneration, KU Leuven, 3000 Leuven, Belgium; (T.B.); (F.O.A.); (K.R.P.V.); (O.C.A.); (E.L.); (L.P.v.d.H.)
- Centre for Molecular and Vascular Biology, Department of Cardiovascular Sciences, KU Leuven, 3000 Leuven, Belgium
| | - Elena Levtchenko
- Department of Development and Regeneration, KU Leuven, 3000 Leuven, Belgium; (T.B.); (F.O.A.); (K.R.P.V.); (O.C.A.); (E.L.); (L.P.v.d.H.)
- Department of Pediatrics, Division of Pediatric Nephrology, University Hospitals Leuven, 3000 Leuven, Belgium
| | - Lambertus P. van den Heuvel
- Department of Development and Regeneration, KU Leuven, 3000 Leuven, Belgium; (T.B.); (F.O.A.); (K.R.P.V.); (O.C.A.); (E.L.); (L.P.v.d.H.)
- Department of Pediatric Nephrology, Radboud University Medical Center, 6500 Nijmegen, The Netherlands
| | - Mohamed A. Elmonem
- Department of Clinical and Chemical Pathology, Faculty of Medicine, Cairo University, Cairo 11628, Egypt
- Correspondence:
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Li Q, Gulati A, Lemaire M, Nottoli T, Bale A, Tufro A. Rho-GTPase Activating Protein myosin MYO9A identified as a novel candidate gene for monogenic focal segmental glomerulosclerosis. Kidney Int 2021; 99:1102-1117. [PMID: 33412162 DOI: 10.1016/j.kint.2020.12.022] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Revised: 12/04/2020] [Accepted: 12/10/2020] [Indexed: 01/18/2023]
Abstract
Focal segmental glomerulosclerosis (FSGS) is a podocytopathy leading to kidney failure, whose molecular cause frequently remains unresolved. Here, we describe a rare MYO9A loss of function nonsense heterozygous mutation (p.Arg701∗) as a possible contributor to disease in a sibling pair with familial FSGS/proteinuria. MYO9A variants of uncertain significance were identified by whole exome sequencing in a cohort of 94 biopsy proven patients with FSGS. MYO9A is an unconventional myosin with a Rho-GAP domain that controls epithelial cell junction assembly, crosslinks and bundles actin and deactivates the small GTPase protein encoded by the RHOA gene. RhoA activity is associated with cytoskeleton regulation of actin stress fiber formation and actomyosin contractility. Myo9A was detected in mouse and human podocytes in vitro and in vivo. Knockin mice carrying the p.Arg701∗MYO9A (Myo9AR701X) generated by gene editing developed proteinuria, podocyte effacement and FSGS. Kidneys and podocytes from Myo9AR701X/+ mutant mice revealed Myo9A haploinsufficiency, increased RhoA activity, decreased Myo9A-actin-calmodulin interaction, impaired podocyte attachment and migration. Our results indicate that Myo9A is a novel component of the podocyte cytoskeletal apparatus that regulates RhoA activity and podocyte function. Thus, Myo9AR701X/+ knock-in mice recapitulate the proband FSGS phenotype, demonstrate that p.R701X Myo9A is an FSGS-causing mutation in mice and suggest that heterozygous loss-of-function MYO9A mutations may cause a novel form of human autosomal dominant FSGS. Hence, identification of MYO9A pathogenic variants in additional individuals with familial or sporadic FSGS is needed to ascertain the gene contribution to disease.
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Affiliation(s)
- Qi Li
- Department of Pediatrics, Nephrology Section, Yale School of Medicine, New Haven, Connecticut, USA
| | - Ashima Gulati
- Department of Internal Medicine, Nephrology Section, Yale School of Medicine, New Haven, Connecticut, USA
| | - Mathieu Lemaire
- Department of Genetics, Yale School of Medicine, New Haven, Connecticut, USA
| | - Timothy Nottoli
- Yale Gene Editing Center, Yale School of Medicine, New Haven, Connecticut, USA
| | - Allen Bale
- Department of Genetics, Yale School of Medicine, New Haven, Connecticut, USA
| | - Alda Tufro
- Department of Pediatrics, Nephrology Section, Yale School of Medicine, New Haven, Connecticut, USA; Department of Cell and Molecular Physiology, Yale School of Medicine, New Haven, Connecticut, USA.
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27
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Gao W, Liu Y, Fan L, Zheng B, Jefferson JR, Wang S, Zhang H, Fang X, Nguyen BV, Zhu T, Roman RJ, Fan F. Role of γ-adducin in actin cytoskeleton rearrangements in podocyte pathophysiology. Am J Physiol Renal Physiol 2021; 320:F97-F113. [PMID: 33308016 PMCID: PMC7847051 DOI: 10.1152/ajprenal.00423.2020] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Revised: 11/24/2020] [Accepted: 11/24/2020] [Indexed: 12/16/2022] Open
Abstract
We recently reported that the enhanced susceptibility to chronic kidney disease (CKD) in the fawn-hooded hypertensive (FHH) rat is caused, at least in part, by a mutation in γ-adducin (ADD3) that attenuates renal vascular function. The present study explored whether Add3 contributes to the modulation of podocyte structure and function using FHH and FHH.Add3 transgenic rats. The expression of ADD3 on the membrane of primary podocytes isolated from FHH was reduced compared with FHH.Add3 transgenic rats. We found that F-actin nets, which are typically localized in the lamellipodia, replaced unbranched stress fibers in conditionally immortalized mouse podocytes transfected with Add3 Dicer-substrate short interfering RNA (DsiRNA) and primary podocytes isolated from FHH rats. There were increased F/G-actin ratios and expression of the Arp2/3 complexes throughout FHH podocytes in association with reduced synaptopodin and RhoA but enhanced Rac1 and CDC42 expression in the renal cortex, glomeruli, and podocytes of FHH rats. The expression of nephrin at the slit diaphragm and the levels of focal adhesion proteins integrin-α3 and integrin-β1 were decreased in the glomeruli of FHH rats. Cell migration was enhanced and adhesion was reduced in podocytes of FHH rats as well as in immortalized mouse podocytes transfected with Add3 DsiRNA. Mean arterial pressures were similar in FHH and FHH.Add3 transgenic rats at 16 wk of age; however, FHH rats exhibited enhanced proteinuria associated with podocyte foot process effacement. These results demonstrate that reduced ADD3 function in FHH rats alters baseline podocyte pathophysiology by rearrangement of the actin cytoskeleton at the onset of proteinuria in young animals.
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Affiliation(s)
- Wenjun Gao
- Department of Urology, Zhongshan Hospital, Fudan University, Shanghai, China
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi
| | - Yedan Liu
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi
| | - Letao Fan
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi
| | - Baoying Zheng
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi
| | - Joshua R Jefferson
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi
| | - Shaoxun Wang
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi
| | - Huawei Zhang
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi
| | - Xing Fang
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi
| | - Bond V Nguyen
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi
| | - Tongyu Zhu
- Department of Urology, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Richard J Roman
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi
| | - Fan Fan
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi
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28
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Schneider R, Deutsch K, Hoeprich GJ, Marquez J, Hermle T, Braun DA, Seltzsam S, Kitzler TM, Mao Y, Buerger F, Majmundar AJ, Onuchic-Whitford AC, Kolvenbach CM, Schierbaum L, Schneider S, Halawi AA, Nakayama M, Mann N, Connaughton DM, Klämbt V, Wagner M, Riedhammer KM, Renders L, Katsura Y, Thumkeo D, Soliman NA, Mane S, Lifton RP, Shril S, Khokha MK, Hoefele J, Goode BL, Hildebrandt F. DAAM2 Variants Cause Nephrotic Syndrome via Actin Dysregulation. Am J Hum Genet 2020; 107:1113-1128. [PMID: 33232676 DOI: 10.1016/j.ajhg.2020.11.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Accepted: 11/05/2020] [Indexed: 01/10/2023] Open
Abstract
The discovery of >60 monogenic causes of nephrotic syndrome (NS) has revealed a central role for the actin regulators RhoA/Rac1/Cdc42 and their effectors, including the formin INF2. By whole-exome sequencing (WES), we here discovered bi-allelic variants in the formin DAAM2 in four unrelated families with steroid-resistant NS. We show that DAAM2 localizes to the cytoplasm in podocytes and in kidney sections. Further, the variants impair DAAM2-dependent actin remodeling processes: wild-type DAAM2 cDNA, but not cDNA representing missense variants found in individuals with NS, rescued reduced podocyte migration rate (PMR) and restored reduced filopodia formation in shRNA-induced DAAM2-knockdown podocytes. Filopodia restoration was also induced by the formin-activating molecule IMM-01. DAAM2 also co-localizes and co-immunoprecipitates with INF2, which is intriguing since variants in both formins cause NS. Using in vitro bulk and TIRF microscopy assays, we find that DAAM2 variants alter actin assembly activities of the formin. In a Xenopus daam2-CRISPR knockout model, we demonstrate actin dysregulation in vivo and glomerular maldevelopment that is rescued by WT-DAAM2 mRNA. We conclude that DAAM2 variants are a likely cause of monogenic human SRNS due to actin dysregulation in podocytes. Further, we provide evidence that DAAM2-associated SRNS may be amenable to treatment using actin regulating compounds.
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29
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Mao Y, Schneider R, van der Ven PFM, Assent M, Lohanadan K, Klämbt V, Buerger F, Kitzler TM, Deutsch K, Nakayama M, Majmundar AJ, Mann N, Hermle T, Onuchic-Whitford AC, Zhou W, Margam NN, Duncan R, Marquez J, Khokha M, Fathy HM, Kari JA, El Desoky S, Eid LA, Awad HS, Al-Saffar M, Mane S, Lifton RP, Fürst DO, Shril S, Hildebrandt F. Recessive Mutations in SYNPO2 as a Candidate of Monogenic Nephrotic Syndrome. Kidney Int Rep 2020; 6:472-483. [PMID: 33615072 PMCID: PMC7879128 DOI: 10.1016/j.ekir.2020.10.040] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2020] [Revised: 10/10/2020] [Accepted: 10/27/2020] [Indexed: 12/28/2022] Open
Abstract
Introduction Most of the approximately 60 genes that if mutated cause steroid-resistant nephrotic syndrome (SRNS) are highly expressed in the glomerular podocyte, rendering SRNS a “podocytopathy.” Methods We performed whole-exome sequencing (WES) in 1200 nephrotic syndrome (NS) patients. Results We discovered homozygous truncating and homozygous missense mutation in SYNPO2 (synaptopodin-2) (p.Lys1124∗ and p.Ala1134Thr) in 2 patients with childhood-onset NS. We found SYNPO2 expression in both podocytes and mesangial cells; however, notably, immunofluorescence staining of adult human and rat kidney cryosections indicated that SYNPO2 is localized mainly in mesangial cells. Subcellular localization studies reveal that in these cells SYNPO2 partially co-localizes with α-actinin and filamin A−containing F-actin filaments. Upon transfection in mesangial cells or podocytes, EGFP-SYNPO2 co-localized with α-actinin-4, which gene is mutated in autosomal dominant SRNS in humans. SYNPO2 overexpression increases mesangial cell migration rate (MMR), whereas shRNA knockdown reduces MMR. Decreased MMR was rescued by transfection of wild-type mouse Synpo2 cDNA but only partially by cDNA representing mutations from the NS patients. The increased mesangial cell migration rate (MMR) by SYNPO2 overexpression was inhibited by ARP complex inhibitor CK666. SYNPO2 shRNA knockdown in podocytes decreased active Rac1, which was rescued by transfection of wild-type SYNPO2 cDNA but not by cDNA representing any of the 2 mutant variants. Conclusion We show that SYNPO2 variants may lead to Rac1-ARP3 dysregulation, and may play a role in the pathogenesis of nephrotic syndrome.
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Affiliation(s)
- Youying Mao
- Department of Pediatrics, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA.,Department of Nephrology, Shanghai Children's Medical Center, Shanhai Jiaotong University, Shanghai, China
| | - Ronen Schneider
- Department of Pediatrics, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Peter F M van der Ven
- Institute for Cell Biology, Department of Molecular Cell Biology, University of Bonn, Bonn, Germany
| | - Marvin Assent
- Institute for Cell Biology, Department of Molecular Cell Biology, University of Bonn, Bonn, Germany
| | - Keerthika Lohanadan
- Institute for Cell Biology, Department of Molecular Cell Biology, University of Bonn, Bonn, Germany
| | - Verena Klämbt
- Department of Pediatrics, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Florian Buerger
- Department of Pediatrics, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Thomas M Kitzler
- Department of Pediatrics, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Konstantin Deutsch
- Department of Pediatrics, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Makiko Nakayama
- Department of Pediatrics, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Amar J Majmundar
- Department of Pediatrics, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Nina Mann
- Department of Pediatrics, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Tobias Hermle
- Department of Pediatrics, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Ana C Onuchic-Whitford
- Department of Pediatrics, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA.,Renal Division, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Wei Zhou
- Department of Nephrology, Shanghai Children's Medical Center, Shanhai Jiaotong University, Shanghai, China
| | | | - Roy Duncan
- Department of Microbiology and Immunology, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Jonathan Marquez
- Department of Pediatrics, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Mustafa Khokha
- Department of Pediatrics, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Hanan M Fathy
- Department of Pediatrics, Alexandria Faculty of medicine, Alexandria University, Alexandria, Egypt
| | - Jameela A Kari
- Department of Pediatrics, King Abdulaziz University, Jeddah, Kingdom of Saudi Arabia.,Pediatric Nephrology Center of Excellence, King Abdulaziz University, Jeddah, Kingdom of Saudi Arabia
| | - Sherif El Desoky
- Department of Pediatrics, King Abdulaziz University, Jeddah, Kingdom of Saudi Arabia.,Pediatric Nephrology Center of Excellence, King Abdulaziz University, Jeddah, Kingdom of Saudi Arabia
| | - Loai A Eid
- Pediatric Nephrology Department, Dubai Kidney Center of Excellence, Dubai Hospital, Dubai, United Arab Emirates
| | - Hazem Subhi Awad
- Pediatric Nephrology Department, Dubai Kidney Center of Excellence, Dubai Hospital, Dubai, United Arab Emirates
| | - Muna Al-Saffar
- Department of Pediatrics, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA.,United Arab Emirates University, Abu Dhabi, United Arab Emirates
| | - Shrikant Mane
- Department of Genetics, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Richard P Lifton
- Department of Genetics, Yale University School of Medicine, New Haven, Connecticut, USA.,Howard Hughes Medical Institute, Chevy Chase, Maryland, USA
| | - Dieter O Fürst
- Institute for Cell Biology, Department of Molecular Cell Biology, University of Bonn, Bonn, Germany
| | - Shirlee Shril
- Department of Pediatrics, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Friedhelm Hildebrandt
- Department of Pediatrics, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA
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30
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Saeed B. Genetic screening in children with challenging nephrotic syndrome. SAUDI JOURNAL OF KIDNEY DISEASES AND TRANSPLANTATION 2020; 31:1189-1197. [PMID: 33565430 DOI: 10.4103/1319-2442.308327] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Genetic screening paradigms for the nephrotic syndrome (NS) in the developed world are well established; however, screening in developing countries has received only minor attention. We retrospectively analyzed a cohort of all children who underwent genetic testing for challenging NS from our registry in the 10-year interval from 2000 to 2010 and based on 58 patients aged 0-12 years with at least one of the following clinical diagnosis: Nonsyndromic steroid-resistant nephrotic syndrome (SRNS), familial NS, and congenital NS. Of these, 23 patients (~40%) had a history of familial disease occurrence. All cases were screened for NPHS2 and WT1 mutations by direct sequencing of all exons of the genes. In addition, all patients who were diagnosed during the first three months of life were screened for NPHS1 mutations too. A genetic disease cause was identified in 12 patients (20.7%); of these, five novel mutations, all in NPHS2 accounting for 42% of all mutations and 9% of the cohort. Nine patients were found to have NPHS2 mutations. Only one case with SRNS had a mutation in WT1. Of the five congenital NS, two cases were found to have NPHS1 mutations and one case with NPHS2 mutation. Therefore, mutations in NPHS2 were the most commonly identified and explained in 15.5% of the screened patients and WT1 mutation in 1.7% of cases, whereas NPHS1 mutations were found in 40% of congenital NS cases. A genetic disease cause was identified in 20.7% of the screened patients. Among 12 identified mutations, abnormalities in NPHS2 (n = 9) were most commonly identified.
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Affiliation(s)
- Bassam Saeed
- Farah Association for Child with Kidney Disease, Damascus, Syria
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31
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Tokhmafshan F, Dickinson K, Akpa MM, Brasell E, Huertas P, Goodyer PR. A no-nonsense approach to hereditary kidney disease. Pediatr Nephrol 2020; 35:2031-2042. [PMID: 31807928 DOI: 10.1007/s00467-019-04394-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/18/2019] [Revised: 07/05/2019] [Accepted: 10/07/2019] [Indexed: 01/12/2023]
Abstract
The advent of a new class of aminoglycosides with increased translational readthrough of nonsense mutations and reduced toxicity offers a new therapeutic strategy for a subset of patients with hereditary kidney disease. The renal uptake and retention of aminoglycosides at a high intracellular concentration makes the kidney an ideal target for this approach. In this review, we explore the potential of aminoglycoside readthrough therapy in a number of hereditary kidney diseases and discuss the therapeutic window of opportunity for subclasses of each disease, when caused by nonsense mutations.
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Affiliation(s)
- Fatima Tokhmafshan
- Research Institute of the McGill University Health Center, 1001 Décarie Boulevard, EM1.2232, Montreal, QC, H4A 3J1, Canada
| | - Kyle Dickinson
- Research Institute of the McGill University Health Center, 1001 Décarie Boulevard, EM1.2232, Montreal, QC, H4A 3J1, Canada.,Department of Experimental Medicine, McGill University, Montreal, Canada
| | - Murielle M Akpa
- Research Institute of the McGill University Health Center, 1001 Décarie Boulevard, EM1.2232, Montreal, QC, H4A 3J1, Canada
| | - Emma Brasell
- Department of Human Genetics, McGill University, Montreal, Canada
| | | | - Paul R Goodyer
- Research Institute of the McGill University Health Center, 1001 Décarie Boulevard, EM1.2232, Montreal, QC, H4A 3J1, Canada. .,Department of Experimental Medicine, McGill University, Montreal, Canada. .,Department of Human Genetics, McGill University, Montreal, Canada. .,Department of Pediatrics, McGill University, Montreal, Canada.
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32
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The potential roles of NAD(P)H:quinone oxidoreductase 1 in the development of diabetic nephropathy and actin polymerization. Sci Rep 2020; 10:17735. [PMID: 33082368 PMCID: PMC7576596 DOI: 10.1038/s41598-020-74493-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Accepted: 09/30/2020] [Indexed: 11/08/2022] Open
Abstract
Diabetic nephropathy (DN) is a major complication of diabetes mellitus. NAD(P)H:quinone oxidoreductase 1 (NQO1) is an antioxidant enzyme that has been involved in the progression of several kidney injuries. However, the roles of NQO1 in DN are still unclear. We investigated the effects of NQO1 deficiency in streptozotocin (STZ)-induced DN mice. NQO1 was upregulated in the glomerulus and podocytes under hyperglycemic conditions. NQO1 knockout (NKO) mice showed more severe changes in blood glucose and body weight than WT mice after STZ treatment. Furthermore, STZ-mediated pathological parameters including glomerular injury, blood urea nitrogen levels, and foot process width were more severe in NKO mice than WT mice. Importantly, urine albumin-to-creatinine ratio (ACR) was higher in healthy, non-treated NKO mice than WT mice. ACR response to STZ or LPS was dramatically increased in the urine of NKO mice compared to vehicle controls, while it maintained a normal range following treatment of WT mice. More importantly, we found that NQO1 can stimulate actin polymerization in an in vitro biochemical assay without directly the accumulation on F-actin. In summary, NQO1 has an important role against the development of DN pathogenesis and is a novel contributor in actin reorganization via stimulating actin polymerization.
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Abstract
Myosins constitute a superfamily of actin-based molecular motor proteins that mediates a variety of cellular activities including muscle contraction, cell migration, intracellular transport, the formation of membrane projections, cell adhesion, and cell signaling. The 12 myosin classes that are expressed in humans share sequence similarities especially in the N-terminal motor domain; however, their enzymatic activities, regulation, ability to dimerize, binding partners, and cellular functions differ. It is becoming increasingly apparent that defects in myosins are associated with diseases including cardiomyopathies, colitis, glomerulosclerosis, neurological defects, cancer, blindness, and deafness. Here, we review the current state of knowledge regarding myosins and disease.
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34
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Randles MJ, Lausecker F, Humphries JD, Byron A, Clark SJ, Miner JH, Zent R, Humphries MJ, Lennon R. Basement membrane ligands initiate distinct signalling networks to direct cell shape. Matrix Biol 2020; 90:61-78. [PMID: 32147508 PMCID: PMC7327512 DOI: 10.1016/j.matbio.2020.02.005] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2019] [Revised: 02/29/2020] [Accepted: 02/29/2020] [Indexed: 01/09/2023]
Abstract
Cells have evolved mechanisms to sense the composition of their adhesive microenvironment. Although much is known about general mechanisms employed by adhesion receptors to relay signals between the extracellular environment and the cytoskeleton, the nuances of ligand-specific signalling remain undefined. Here, we investigated how glomerular podocytes, and four other basement membrane-associated cell types, respond morphologically to different basement membrane ligands. We defined the composition of the respective adhesion complexes using mass spectrometry-based proteomics. On type IV collagen, all epithelial cell types adopted a round morphology, with a single lamellipodium and large adhesion complexes rich in actin-binding proteins. On laminin (511 or 521), all cell types attached to a similar degree but were polygonal in shape with small adhesion complexes enriched in endocytic and microtubule-binding proteins. Consistent with their distinctive morphologies, cells on type IV collagen exhibited high Rac1 activity, while those on laminin had elevated PKCα. Perturbation of PKCα was able to interchange morphology consistent with a key role for this pathway in matrix ligand-specific signalling. Therefore, this study defines the switchable basement membrane adhesome and highlights two key signalling pathways within the systems that determine distinct cell morphologies. Proteomic data are availableviaProteomeXchange with identifier PXD017913.
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Affiliation(s)
- Michael J Randles
- Wellcome Centre for Cell-Matrix Research, Division of Cell-Matrix Biology and Regenerative Medicine, School of Biological Sciences, Faculty of Biology Medicine and Health, The University of Manchester, Manchester Academic Health Science Centre, Manchester, UK
| | - Franziska Lausecker
- Wellcome Centre for Cell-Matrix Research, Division of Cell-Matrix Biology and Regenerative Medicine, School of Biological Sciences, Faculty of Biology Medicine and Health, The University of Manchester, Manchester Academic Health Science Centre, Manchester, UK
| | - Jonathan D Humphries
- Wellcome Centre for Cell-Matrix Research, Division of Cell-Matrix Biology and Regenerative Medicine, School of Biological Sciences, Faculty of Biology Medicine and Health, The University of Manchester, Manchester Academic Health Science Centre, Manchester, UK
| | - Adam Byron
- Cancer Research UK Edinburgh Centre, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, UK
| | - Simon J Clark
- Universitäts-Augenklinik Tübingen, Eberhard Karls University of Tübingen, Germany; The Lydia Becker Institute of Immunology and Inflammation, Faculty of Biology Medicine and Health, The University of Manchester, Manchester, UK
| | - Jeffrey H Miner
- Renal Division, Washington University School of Medicine, Saint Louis, MO, USA
| | - Roy Zent
- Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Martin J Humphries
- Wellcome Centre for Cell-Matrix Research, Division of Cell-Matrix Biology and Regenerative Medicine, School of Biological Sciences, Faculty of Biology Medicine and Health, The University of Manchester, Manchester Academic Health Science Centre, Manchester, UK
| | - Rachel Lennon
- Wellcome Centre for Cell-Matrix Research, Division of Cell-Matrix Biology and Regenerative Medicine, School of Biological Sciences, Faculty of Biology Medicine and Health, The University of Manchester, Manchester Academic Health Science Centre, Manchester, UK; Department of Paediatric Nephrology, Royal Manchester Children's Hospital, Manchester University Hospitals NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester, UK.
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Blaine J, Dylewski J. Regulation of the Actin Cytoskeleton in Podocytes. Cells 2020; 9:cells9071700. [PMID: 32708597 PMCID: PMC7408282 DOI: 10.3390/cells9071700] [Citation(s) in RCA: 53] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Revised: 06/30/2020] [Accepted: 07/07/2020] [Indexed: 12/13/2022] Open
Abstract
Podocytes are an integral part of the glomerular filtration barrier, a structure that prevents filtration of large proteins and macromolecules into the urine. Podocyte function is dependent on actin cytoskeleton regulation within the foot processes, structures that link podocytes to the glomerular basement membrane. Actin cytoskeleton dynamics in podocyte foot processes are complex and regulated by multiple proteins and other factors. There are two key signal integration and structural hubs within foot processes that regulate the actin cytoskeleton: the slit diaphragm and focal adhesions. Both modulate actin filament extension as well as foot process mobility. No matter what the initial cause, the final common pathway of podocyte damage is dysregulation of the actin cytoskeleton leading to foot process retraction and proteinuria. Disruption of the actin cytoskeleton can be due to acquired causes or to genetic mutations in key actin regulatory and signaling proteins. Here, we describe the major structural and signaling components that regulate the actin cytoskeleton in podocytes as well as acquired and genetic causes of actin dysregulation.
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Affiliation(s)
- Judith Blaine
- Renal Division, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA;
| | - James Dylewski
- Renal Division, University of Colorado Anschutz Medical Campus and Denver Health Medical Center, Aurora, CO 80045, USA
- Correspondence: ; Tel.: +303-724-4841
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Feng D, Kumar M, Muntel J, Gurley SB, Birrane G, Stillman IE, Ding L, Wang M, Ahmed S, Schlondorff J, Alper SL, Ferrante T, Marquez SL, Ng CF, Novak R, Ingber DE, Steen H, Pollak MR. Phosphorylation of ACTN4 Leads to Podocyte Vulnerability and Proteinuric Glomerulosclerosis. J Am Soc Nephrol 2020; 31:1479-1495. [PMID: 32540856 PMCID: PMC7351002 DOI: 10.1681/asn.2019101032] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2019] [Accepted: 03/23/2020] [Indexed: 01/07/2023] Open
Abstract
BACKGROUND Genetic mutations in α-actinin-4 (ACTN4)-an important actin crosslinking cytoskeletal protein that provides structural support for kidney podocytes-have been linked to proteinuric glomerulosclerosis in humans. However, the effect of post-translational modifications of ACTN4 on podocyte integrity and kidney function is not known. METHODS Using mass spectrometry, we found that ACTN4 is phosphorylated at serine (S) 159 in human podocytes. We used phosphomimetic and nonphosphorylatable ACTN4 to comprehensively study the effects of this phosphorylation in vitro and in vivo. We conducted x-ray crystallography, F-actin binding and bundling assays, and immunofluorescence staining to evaluate F-actin alignment. Microfluidic organ-on-a-chip technology was used to assess for detachment of podocytes simultaneously exposed to fluid flow and cyclic strain. We then used CRISPR/Cas9 to generate mouse models and assessed for renal injury by measuring albuminuria and examining kidney histology. We also performed targeted mass spectrometry to determine whether high extracellular glucose or TGF-β levels increase phosphorylation of ACTN4. RESULTS Compared with the wild type ACTN4, phosphomimetic ACTN4 demonstrated increased binding and bundling activity with F-actin in vitro. Phosphomimetic Actn4 mouse podocytes exhibited more spatially correlated F-actin alignment and a higher rate of detachment under mechanical stress. Phosphomimetic Actn4 mice developed proteinuria and glomerulosclerosis after subtotal nephrectomy. Moreover, we found that exposure to high extracellular glucose or TGF-β stimulates phosphorylation of ACTN4 at S159 in podocytes. CONCLUSIONS These findings suggest that increased phosphorylation of ACTN4 at S159 leads to biochemical, cellular, and renal pathology that is similar to pathology resulting from human disease-causing mutations in ACTN4. ACTN4 may mediate podocyte injury as a consequence of both genetic mutations and signaling events that modulate phosphorylation.
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Affiliation(s)
- Di Feng
- Division of Nephrology, Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts,Wyss Institute for Biologically Inspired Engineering at Harvard University, Boston, Massachusetts
| | - Mukesh Kumar
- Department of Pathology, Boston Children’s Hospital and Harvard Medical School, Boston, Massachusetts,F.M. Kirby Neurobiology Center, Department of Neurobiology, Boston Children’s Hospital, Boston, Massachusetts
| | | | - Susan B. Gurley
- Division of Nephrology and Hypertension, Oregon Health & Science University, Portland, Oregon
| | - Gabriel Birrane
- Division of Experimental Medicine, Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts
| | - Isaac E. Stillman
- Division of Nephrology, Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts,Department of Pathology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts
| | - Lai Ding
- NeuroTechnology Studio, Program for Interdisciplinary Neuroscience, Brigham and Women’s Hospital, Boston, Massachusetts
| | - Minxian Wang
- Broad Institute of Harvard and Massachusetts Institute of Technology, Cambridge, Massachusetts
| | - Saima Ahmed
- Department of Pathology, Boston Children’s Hospital and Harvard Medical School, Boston, Massachusetts
| | - Johannes Schlondorff
- Division of Nephrology, Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts
| | - Seth L. Alper
- Division of Nephrology, Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts,Broad Institute of Harvard and Massachusetts Institute of Technology, Cambridge, Massachusetts
| | - Tom Ferrante
- Wyss Institute for Biologically Inspired Engineering at Harvard University, Boston, Massachusetts
| | - Susan L. Marquez
- Wyss Institute for Biologically Inspired Engineering at Harvard University, Boston, Massachusetts
| | - Carlos F. Ng
- Wyss Institute for Biologically Inspired Engineering at Harvard University, Boston, Massachusetts
| | - Richard Novak
- Wyss Institute for Biologically Inspired Engineering at Harvard University, Boston, Massachusetts
| | - Donald E. Ingber
- Wyss Institute for Biologically Inspired Engineering at Harvard University, Boston, Massachusetts,Vascular Biology Program, Boston Children’s Hospital and Harvard Medical School, Boston, Massachusetts,Department of Surgery, Boston Children’s Hospital and Harvard Medical School, Boston, Massachusetts,Harvard John A. Paulson School of Engineering and Applied Sciences, Cambridge, Massachusetts
| | - Hanno Steen
- Department of Pathology, Boston Children’s Hospital and Harvard Medical School, Boston, Massachusetts
| | - Martin R. Pollak
- Division of Nephrology, Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts,Broad Institute of Harvard and Massachusetts Institute of Technology, Cambridge, Massachusetts
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Park E, Lee C, Kim NKD, Ahn YH, Park YS, Lee JH, Kim SH, Cho MH, Cho H, Yoo KH, Shin JI, Kang HG, Ha IS, Park WY, Cheong HI. Genetic Study in Korean Pediatric Patients with Steroid-Resistant Nephrotic Syndrome or Focal Segmental Glomerulosclerosis. J Clin Med 2020; 9:jcm9062013. [PMID: 32604935 PMCID: PMC7355646 DOI: 10.3390/jcm9062013] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Revised: 06/16/2020] [Accepted: 06/19/2020] [Indexed: 11/17/2022] Open
Abstract
Steroid-resistant nephrotic syndrome (SRNS) is one of the major causes of end-stage renal disease (ESRD) in childhood and is mostly associated with focal segmental glomerulosclerosis (FSGS). More than 50 monogenic causes of SRNS or FSGS have been identified. Recently, the mutation detection rate in pediatric patients with SRNS has been reported to be approximately 30%. In this study, genotype-phenotype correlations in a cohort of 291 Korean pediatric patients with SRNS/FSGS were analyzed. The overall mutation detection rate was 43.6% (127 of 291 patients). WT1 was the most common causative gene (23.6%), followed by COQ6 (8.7%), NPHS1 (8.7%), NUP107 (7.1%), and COQ8B (6.3%). Mutations in COQ6, NUP107, and COQ8B were more frequently detected, and mutations in NPHS2 were less commonly detected in this cohort than in study cohorts from Western countries. The mutation detection rate was higher in patients with congenital onset, those who presented with proteinuria or chronic kidney disease/ESRD, and those who did not receive steroid treatment. Genetic diagnosis in patients with SRNS provides not only definitive diagnosis but also valuable information for decisions on treatment policy and prediction of prognosis. Therefore, further genotype-phenotype correlation studies are required.
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Affiliation(s)
- Eujin Park
- Department of Pediatrics, Seoul National University College of Medicine, Seoul 03080, Korea; (E.P.); (Y.H.A.); (H.G.K.); (I.-S.H.)
- Department of Pediatrics, Kangnam Sacred Heart Hospital, Hallym University College of Medicine, Seoul 07441, Korea
| | - Chung Lee
- Samsung Genome Institute, Samsung Medical Center, Seoul 06351, Korea; (C.L.); (N.K.D.K.); (W.-Y.P.)
- GENINUS Inc., Seoul 05836, Korea
| | - Nayoung K. D. Kim
- Samsung Genome Institute, Samsung Medical Center, Seoul 06351, Korea; (C.L.); (N.K.D.K.); (W.-Y.P.)
- GENINUS Inc., Seoul 05836, Korea
| | - Yo Han Ahn
- Department of Pediatrics, Seoul National University College of Medicine, Seoul 03080, Korea; (E.P.); (Y.H.A.); (H.G.K.); (I.-S.H.)
| | - Young Seo Park
- Department of Pediatrics, Asan Medical Center Children’s Hospital, University of Ulsan College of Medicine, Seoul 05505, Korea; (Y.S.P.); (J.H.L.)
| | - Joo Hoon Lee
- Department of Pediatrics, Asan Medical Center Children’s Hospital, University of Ulsan College of Medicine, Seoul 05505, Korea; (Y.S.P.); (J.H.L.)
| | - Seong Heon Kim
- Department of Pediatrics, Pusan National University Children’s Hospital, Yangsan 50612, Korea;
| | - Min Hyun Cho
- Department of Pediatrics, Kyungpook National University School of Medicine, Daegu 41944, Korea;
| | - Heeyeon Cho
- Department of Pediatrics, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul 06351, Korea;
| | - Kee Hwan Yoo
- Department of Pediatrics, Korea University Guro Hospital, Seoul 02841, Korea;
| | - Jae Il Shin
- Department of Pediatrics, Yonsei University College of Medicine, Seoul 03722, Korea;
- Division of Pediatric Nephrology, Severance Children’s Hospital, Seoul 03722, Korea
| | - Hee Gyung Kang
- Department of Pediatrics, Seoul National University College of Medicine, Seoul 03080, Korea; (E.P.); (Y.H.A.); (H.G.K.); (I.-S.H.)
| | - Il-Soo Ha
- Department of Pediatrics, Seoul National University College of Medicine, Seoul 03080, Korea; (E.P.); (Y.H.A.); (H.G.K.); (I.-S.H.)
| | - Woong-Yang Park
- Samsung Genome Institute, Samsung Medical Center, Seoul 06351, Korea; (C.L.); (N.K.D.K.); (W.-Y.P.)
- GENINUS Inc., Seoul 05836, Korea
- Department of Molecular Cell Biology, Sungkyunkwan University School of Medicine, Suwon 16419, Korea
| | - Hae Il Cheong
- Department of Pediatrics, Seoul National University College of Medicine, Seoul 03080, Korea; (E.P.); (Y.H.A.); (H.G.K.); (I.-S.H.)
- Correspondence: ; Tel.: +82-2-2072-2810
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Yarwood R, Hellicar J, Woodman PG, Lowe M. Membrane trafficking in health and disease. Dis Model Mech 2020; 13:13/4/dmm043448. [PMID: 32433026 PMCID: PMC7197876 DOI: 10.1242/dmm.043448] [Citation(s) in RCA: 67] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Membrane trafficking pathways are essential for the viability and growth of cells, and play a major role in the interaction of cells with their environment. In this At a Glance article and accompanying poster, we outline the major cellular trafficking pathways and discuss how defects in the function of the molecular machinery that mediates this transport lead to various diseases in humans. We also briefly discuss possible therapeutic approaches that may be used in the future treatment of trafficking-based disorders. Summary: This At a Glance article and poster summarise the major intracellular membrane trafficking pathways and associated molecular machineries, and describe how defects in these give rise to disease in humans.
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Affiliation(s)
- Rebecca Yarwood
- School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, M13 9PT, UK
| | - John Hellicar
- School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, M13 9PT, UK
| | - Philip G Woodman
- School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, M13 9PT, UK
| | - Martin Lowe
- School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, M13 9PT, UK
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Riedhammer KM, Braunisch MC, Günthner R, Wagner M, Hemmer C, Strom TM, Schmaderer C, Renders L, Tasic V, Gucev Z, Nushi-Stavileci V, Putnik J, Stajić N, Weidenbusch M, Uetz B, Montoya C, Strotmann P, Ponsel S, Lange-Sperandio B, Hoefele J. Exome Sequencing and Identification of Phenocopies in Patients With Clinically Presumed Hereditary Nephropathies. Am J Kidney Dis 2020; 76:460-470. [PMID: 32359821 DOI: 10.1053/j.ajkd.2019.12.008] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2019] [Accepted: 12/15/2019] [Indexed: 12/11/2022]
Abstract
RATIONALE & OBJECTIVE Hereditary nephropathies are clinically and genetically heterogeneous disorders. For some patients, the clinical phenotype corresponds to a specific hereditary disease but genetic testing reveals that the expected genotype is not present (phenocopy). The aim of this study was to evaluate the spectrum and frequency of phenocopies identified by using exome sequencing in a cohort of patients who were clinically suspected to have hereditary kidney disorders. STUDY DESIGN Cross-sectional cohort study. SETTING & PARTICIPANTS 174 unrelated patients were recruited for exome sequencing and categorized into 7 disease groups according to their clinical presentation. They included autosomal dominant tubulointerstitial kidney disease, Alport syndrome, congenital anomalies of the kidney and urinary tract, ciliopathy, focal segmental glomerulosclerosis/steroid-resistant nephrotic syndrome, VACTERL association, and "other." RESULTS A genetic diagnosis (either likely pathogenic or pathogenic variant according to the guidelines of the American College of Medical Genetics) was established using exome sequencing in 52 of 174 (30%) cases. A phenocopy was identified for 10 of the 52 exome sequencing-solved cases (19%), representing 6% of the total cohort. The most frequent phenocopies (n=5) were associated with genetic Alport syndrome presenting clinically as focal segmental glomerulosclerosis/steroid-resistant nephrotic syndrome. Strictly targeted gene panels (<25 kilobases) did not identify any of the phenocopy cases. LIMITATIONS The spectrum of described phenocopies is small. Selection bias may have altered the diagnostic yield within disease groups in our study population. The study cohort was predominantly of non-Finnish European descent, limiting generalizability. Certain hereditary kidney diseases cannot be diagnosed by using exome sequencing (eg, MUC1-autosomal dominant tubulointerstitial kidney disease). CONCLUSIONS Phenocopies led to the recategorization of disease and altered clinical management. This study highlights that exome sequencing can detect otherwise occult genetic heterogeneity of kidney diseases.
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Affiliation(s)
- Korbinian M Riedhammer
- Institute of Human Genetics, Klinikum rechts der Isar, School of Medicine, Technical University of Munich, Munich, Germany; Department of Nephrology, Klinikum rechts der Isar, School of Medicine, Technical University of Munich, Munich, Germany
| | - Matthias C Braunisch
- Institute of Human Genetics, Klinikum rechts der Isar, School of Medicine, Technical University of Munich, Munich, Germany; Department of Nephrology, Klinikum rechts der Isar, School of Medicine, Technical University of Munich, Munich, Germany
| | - Roman Günthner
- Institute of Human Genetics, Klinikum rechts der Isar, School of Medicine, Technical University of Munich, Munich, Germany; Department of Nephrology, Klinikum rechts der Isar, School of Medicine, Technical University of Munich, Munich, Germany
| | - Matias Wagner
- Institute of Human Genetics, Klinikum rechts der Isar, School of Medicine, Technical University of Munich, Munich, Germany; Institute of Neurogenomics, Helmholtz Zentrum München, Neuherberg, Germany; Institute of Human Genetics, Helmholtz Zentrum München, Neuherberg, Germany
| | - Clara Hemmer
- Institute of Human Genetics, Klinikum rechts der Isar, School of Medicine, Technical University of Munich, Munich, Germany
| | - Tim M Strom
- Institute of Human Genetics, Helmholtz Zentrum München, Neuherberg, Germany
| | - Christoph Schmaderer
- Department of Nephrology, Klinikum rechts der Isar, School of Medicine, Technical University of Munich, Munich, Germany
| | - Lutz Renders
- Department of Nephrology, Klinikum rechts der Isar, School of Medicine, Technical University of Munich, Munich, Germany
| | - Velibor Tasic
- University Children's Hospital, Medical Faculty of Skopje, Macedonia
| | - Zoran Gucev
- University Children's Hospital, Medical Faculty of Skopje, Macedonia
| | | | - Jovana Putnik
- Institute for Mother and Child Health Care of Serbia "Dr Vukan Čupić", Department of Nephrology, University of Belgrade, Faculty of Medicine, Belgrade, Serbia
| | - Nataša Stajić
- Institute for Mother and Child Health Care of Serbia "Dr Vukan Čupić", Department of Nephrology, University of Belgrade, Faculty of Medicine, Belgrade, Serbia
| | - Marc Weidenbusch
- Nephrologisches Zentrum, Medizinische Klinik und Poliklinik IV, Klinikum der Universität München, Ludwig-Maximilians University, Munich, Germany
| | - Barbara Uetz
- München-Klinik Schwabing, Klinikum rechts der Isar, Technical University of Munich, Children's Hospital, Pediatric Nephrology, Munich, Germany; KfH-Kindernierenzentrum, Munich, Germany
| | | | - Peter Strotmann
- München-Klinik Schwabing, Klinikum rechts der Isar, Technical University of Munich, Children's Hospital, Pediatric Nephrology, Munich, Germany
| | - Sabine Ponsel
- Division of Pediatric Nephrology, Dr. v. Hauner Children's Hospital, Ludwig-Maximilians University, Munich, Germany
| | - Baerbel Lange-Sperandio
- Division of Pediatric Nephrology, Dr. v. Hauner Children's Hospital, Ludwig-Maximilians University, Munich, Germany
| | - Julia Hoefele
- Institute of Human Genetics, Klinikum rechts der Isar, School of Medicine, Technical University of Munich, Munich, Germany.
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Navinés-Ferrer A, Martín M. Long-Tailed Unconventional Class I Myosins in Health and Disease. Int J Mol Sci 2020; 21:ijms21072555. [PMID: 32272642 PMCID: PMC7177449 DOI: 10.3390/ijms21072555] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Revised: 04/03/2020] [Accepted: 04/04/2020] [Indexed: 01/21/2023] Open
Abstract
Long-tailed unconventional class I myosin, Myosin 1E (MYO1E) and Myosin 1F (MYO1F) are motor proteins that use chemical energy from the hydrolysis of adenosine triphosphate (ATP) to produce mechanical work along the actin cytoskeleton. On the basis of their motor properties and structural features, myosins perform a variety of essential roles in physiological processes such as endocytosis, exocytosis, cell adhesion, and migration. The long tailed unconventional class I myosins are characterized by having a conserved motor head domain, which binds actin and hydrolyzes ATP, followed by a short neck with an isoleucine-glutamine (IQ) motif, which binds calmodulin and is sensitive to calcium, and a tail that contains a pleckstrin homology domain (PH), a tail homology 1 domain (TH1), wherein these domains allow membrane binding, a tail homology 2 domain (TH2), an ATP-insensitive actin-binding site domain, and a single Src homology 3 domain (SH3) susceptible to binding proline rich regions in other proteins. Therefore, these motor proteins are able to bind actin, plasma membrane, and other molecules (adaptor, kinases, membrane proteins) that contribute to their function, ranging from increasing membrane tension to molecular trafficking and cellular adhesion. MYO1E and MYO1F function in host self-defense, with a better defined role in innate immunity in cell migration and phagocytosis. Impairments of their function have been identified in patients suffering pathologies ranging from tumoral processes to kidney diseases. In this review, we summarize our current knowledge of specific features and functions of MYO1E and MYO1F in various tissues, as well as their involvement in disease.
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Affiliation(s)
- A. Navinés-Ferrer
- Biochemistry and Molecular Biology Unit, Biomedicine Department, Faculty of Medicine, University of Barcelona, 08036 Barcelona, Spain
- Laboratory of Clinic and Experimental Respiratory Immunoallergy, IDIBAPS, 08036 Barcelona, Spain
| | - M. Martín
- Biochemistry and Molecular Biology Unit, Biomedicine Department, Faculty of Medicine, University of Barcelona, 08036 Barcelona, Spain
- Laboratory of Clinic and Experimental Respiratory Immunoallergy, IDIBAPS, 08036 Barcelona, Spain
- ARADyAL research network, Carlos III Health Institute, 28029 Madrid, Spain
- Correspondence: ; Tel.: +34-93-4024541; Fax: +34-93-4035882
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Shen H, Bao Y, Feng C, Fu H, Mao J. Overexpression of Myo1e promotes albumin endocytosis by mouse glomerular podocytes mediated by Dynamin. PeerJ 2020; 8:e8599. [PMID: 32211226 PMCID: PMC7083160 DOI: 10.7717/peerj.8599] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Accepted: 01/19/2020] [Indexed: 11/20/2022] Open
Abstract
Background As a fundamental process internalizing molecules from the plasma membrane, endocytosis plays a crucial role in podocyte biology. Our previous study has identified that overexpression of Myole may enhance podocyte endocytosis. However, its potential mechanism has been not well understand. Thus, we aimed to analyze whether albumin endocytosis by mouse glomerular podocytes is dependent on Myo1e expression. Also, we aimed to elucidate whether the underlying mechanism is mediated by Dynamin. Methods Firstly, mouse podocyte cells (MPC5) were treated with different concentrations of FITC-bovine serum albumin (BSA). The fluorescence intensity and cell viability were detected by flow cytometry and MTT assays, respectively. Afterwards, the optimal concentration of FITC-BSA was determined. Secondly, MPC5 cells were treated with Myole overexpression or knockdown. Cell morphology was observed under microscope. Immunofluorescence assay was used to determine the expression of F-actin. The protein expression of nephrin and podocin was detected by western blot. Flow cytometry was used to detect MPC5 cell apoptosis with annexin V. Finally, MPC5 cells were treated with Myole overexpression and/or Dynasore (a GTPase inhibitor of Dynamin). The fluorescence intensity was detected using flow cytometry assay. Results MPC5 endocytosis BSA was elevated with a concentration-dependent manner. MTT results showed that MPC5 cell viability was inhibited with a concentration-dependent manner. Myo1e overexpression promoted podocyte endocytic FITC-BSA, which was contrary to its knockdown. Under microscope, after inhibition of Myo1e, podocyte foot process fusion was observed. Myo1e overexpression promoted the expression of cytoskeleton F-actin and podocyte-specific molecules (nephrin and podocin) in podocyte endocytic FITC-BSA. Furthermore, we found that Myo1e promoted the apoptosis of podocytes. Dynasore attenuated the increase in endocytosis of FITC-BSA induced by Myo1e overexpression, suggesting that podocytes might mediate albumin endocytosis via Myo1e-Dynamin-Albumin. Conclusion Our findings revealed that overexpression of Myo1e promotes albumin endocytosis in mouse glomerular podocyte endocytic albumin mediated by Dynamin.
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Affiliation(s)
- Huijun Shen
- Department of Nephrology, The Children's Hospital of Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Yu Bao
- Department of Nephrology, The Children's Hospital of Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Chunyue Feng
- Department of Nephrology, The Children's Hospital of Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Haidong Fu
- Department of Nephrology, The Children's Hospital of Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Jianhua Mao
- Department of Nephrology, The Children's Hospital of Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
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Li AS, Ingham JF, Lennon R. Genetic Disorders of the Glomerular Filtration Barrier. Clin J Am Soc Nephrol 2020; 15:1818-1828. [PMID: 32205319 PMCID: PMC7769017 DOI: 10.2215/cjn.11440919] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The glomerular filtration barrier is a highly specialized capillary wall comprising fenestrated endothelial cells, podocytes, and an intervening basement membrane. In glomerular disease, this barrier loses functional integrity, allowing the passage of macromolecules and cells, and there are associated changes in both cell morphology and the extracellular matrix. Over the past 3 decades, there has been a transformation in our understanding about glomerular disease, fueled by genetic discovery, and this is leading to exciting advances in our knowledge about glomerular biology and pathophysiology. In current clinical practice, a genetic diagnosis already has important implications for management, ranging from estimating the risk of disease recurrence post-transplant to the life-changing advances in the treatment of atypical hemolytic uremic syndrome. Improving our understanding about the mechanistic basis of glomerular disease is required for more effective and personalized therapy options. In this review, we describe genotype and phenotype correlations for genetic disorders of the glomerular filtration barrier, with a particular emphasis on how these gene defects cluster by both their ontology and patterns of glomerular pathology.
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Affiliation(s)
- Anna S Li
- Division of Cell-Matrix Biology and Regenerative Medicine, Wellcome Centre for Cell-Matrix Research, School of Biological Sciences, Faculty of Biology, Medicine and Health, Manchester Academic Health Science Centre, The University of Manchester, Manchester, United Kingdom.,Department of Nephrology, Manchester University Hospitals National Health Service Foundation Trust, Manchester Academic Health Science Centre, Manchester, United Kingdom
| | - Jack F Ingham
- Division of Cell-Matrix Biology and Regenerative Medicine, Wellcome Centre for Cell-Matrix Research, School of Biological Sciences, Faculty of Biology, Medicine and Health, Manchester Academic Health Science Centre, The University of Manchester, Manchester, United Kingdom
| | - Rachel Lennon
- Division of Cell-Matrix Biology and Regenerative Medicine, Wellcome Centre for Cell-Matrix Research, School of Biological Sciences, Faculty of Biology, Medicine and Health, Manchester Academic Health Science Centre, The University of Manchester, Manchester, United Kingdom .,Department of Paediatric Nephrology, Royal Manchester Children's Hospital, Manchester University Hospitals National Health Service Foundation Trust, Manchester Academic Health Science Centre, Manchester, United Kingdom
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43
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BENZING THOMAS. MOLECULAR DESIGN OF THE KIDNEY FILTRATION BARRIER. TRANSACTIONS OF THE AMERICAN CLINICAL AND CLIMATOLOGICAL ASSOCIATION 2020; 131:125-139. [PMID: 32675853 PMCID: PMC7358502] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Kidneys are the central regulators of organismal homeostasis. These organs filter enormous amounts of fluid from plasma; excrete toxic waste products; maintain salt, water, and volume balance; coordinate blood pressure regulation; and maintain the acid-base equilibrium essential for life. Although it has been known for decades that renal glomeruli serve as the site of plasma ultrafiltration and urine production, both the molecular design and function of the kidney filtration barrier have remained elusive. Indeed, the past two decades have witnessed enormous breakthroughs in our fundamental understanding of kidney filtration and the critical role that podocytes, specialized terminally differentiated epithelial cells at the glomerular capillaries, fulfill in the function of the kidney filtration barrier. Here we discuss recent advances in this field that will change the way we think about plasma ultrafiltration in health and proteinuria as a manifestation of glomerular diseases.
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Affiliation(s)
- THOMAS BENZING
- Correspondence and reprint requests: Thomas Benzing, MD, Department II of Internal Medicine, University of Cologne, Kerpener Str. 62, 50937 Cologne, Germany+ 49 221 4784480, 49 221 4785959
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Falcone S, Wisby L, Nicol T, Blease A, Starbuck B, Parker A, Sanderson J, Brown SDM, Scudamore CL, Pusey CD, Tam FWK, Potter PK. Modification of an aggressive model of Alport Syndrome reveals early differences in disease pathogenesis due to genetic background. Sci Rep 2019; 9:20398. [PMID: 31892712 PMCID: PMC6938516 DOI: 10.1038/s41598-019-56837-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Accepted: 12/05/2019] [Indexed: 12/13/2022] Open
Abstract
The link between mutations in collagen genes and the development of Alport Syndrome has been clearly established and a number of animal models, including knock-out mouse lines, have been developed that mirror disease observed in patients. However, it is clear from both patients and animal models that the progression of disease can vary greatly and can be modified genetically. We have identified a point mutation in Col4a4 in mice where disease is modified by strain background, providing further evidence of the genetic modification of disease symptoms. Our results indicate that C57BL/6J is a protective background and postpones end stage renal failure from 7 weeks, as seen on a C3H background, to several months. We have identified early differences in disease progression, including expression of podocyte-specific genes and podocyte morphology. In C57BL/6J mice podocyte effacement is delayed, prolonging normal renal function. The slower disease progression has allowed us to begin dissecting the pathogenesis of murine Alport Syndrome in detail. We find that there is evidence of differential gene expression during disease on the two genetic backgrounds, and that disease diverges by 4 weeks of age. We also show that an inflammatory response with increasing MCP-1 and KIM-1 levels precedes loss of renal function.
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Affiliation(s)
- Sara Falcone
- Mammalian Genetics Unit, Medical Research Council, Harwell science and innovation campus, Oxford, OX11 0RD, UK
| | - Laura Wisby
- Mammalian Genetics Unit, Medical Research Council, Harwell science and innovation campus, Oxford, OX11 0RD, UK
| | - Thomas Nicol
- Mammalian Genetics Unit, Medical Research Council, Harwell science and innovation campus, Oxford, OX11 0RD, UK
| | - Andrew Blease
- Mammalian Genetics Unit, Medical Research Council, Harwell science and innovation campus, Oxford, OX11 0RD, UK
| | - Becky Starbuck
- Mammalian Genetics Unit, Medical Research Council, Harwell science and innovation campus, Oxford, OX11 0RD, UK
| | - Andrew Parker
- Mammalian Genetics Unit, Medical Research Council, Harwell science and innovation campus, Oxford, OX11 0RD, UK
| | - Jeremy Sanderson
- Mammalian Genetics Unit, Medical Research Council, Harwell science and innovation campus, Oxford, OX11 0RD, UK
| | - Steve D M Brown
- Mammalian Genetics Unit, Medical Research Council, Harwell science and innovation campus, Oxford, OX11 0RD, UK
| | - Cheryl L Scudamore
- Mary Lyon Centre, Medical Research Council, Harwell science and innovation campus, Oxford, OX11 0RD, UK
| | - Charles D Pusey
- Renal and Vascular Inflammation Section, Department of Medicine, Imperial College, London, W12 0N, UK
| | - Frederick W K Tam
- Renal and Vascular Inflammation Section, Department of Medicine, Imperial College, London, W12 0N, UK
| | - Paul K Potter
- Renal and Vascular Inflammation Section, Department of Medicine, Imperial College, London, W12 0N, UK.
- Department of Biological and Medical Sciences, Faculty of Health and Life Sciences, Oxford Brookes University, Oxford, OX3 0BP, UK.
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Schapiro D, Daga A, Lawson JA, Majmundar AJ, Lovric S, Tan W, Warejko JK, Fessi I, Rao J, Airik M, Gee HY, Schneider R, Widmeier E, Hermle T, Ashraf S, Jobst-Schwan T, van der Ven AT, Nakayama M, Shril S, Braun DA, Hildebrandt F. Panel sequencing distinguishes monogenic forms of nephritis from nephrosis in children. Nephrol Dial Transplant 2019; 34:474-485. [PMID: 30295827 DOI: 10.1093/ndt/gfy050] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2017] [Accepted: 01/21/2018] [Indexed: 01/09/2023] Open
Abstract
BACKGROUND Alport syndrome (AS) and atypical hemolytic-uremic syndrome (aHUS) are rare forms of chronic kidney disease (CKD) that can lead to a severe decline of renal function. Steroid-resistant nephrotic syndrome (SRNS) is more common than AS and aHUS and causes 10% of childhood-onset CKD. In recent years, multiple monogenic causes of AS, aHUS and SRNS have been identified, but their relative prevalence has yet to be studied together in a typical pediatric cohort of children with proteinuria and hematuria. We hypothesized that identification of causative mutations by whole exome sequencing (WES) in known monogenic nephritis and nephrosis genes would allow distinguishing nephritis from nephrosis in a typical pediatric group of patients with both proteinuria and hematuria at any level. METHODS We therefore conducted an exon sequencing (WES) analysis for 11 AS, aHUS and thrombotic thrombocytopenic purpura-causing genes in an international cohort of 371 patients from 362 families presenting with both proteinuria and hematuria before age 25 years. In parallel, we conducted either WES or high-throughput exon sequencing for 23 SRNS-causing genes in all patients. RESULTS We detected pathogenic mutations in 18 of the 34 genes analyzed, leading to a molecular diagnosis in 14.1% of families (51 of 362). Disease-causing mutations were detected in 3 AS-causing genes (4.7%), 3 aHUS-causing genes (1.4%) and 12 NS-causing genes (8.0%). We observed a much higher mutation detection rate for monogenic forms of CKD in consanguineous families (35.7% versus 10.1%). CONCLUSIONS We present the first estimate of relative frequency of inherited AS, aHUS and NS in a typical pediatric cohort with proteinuria and hematuria. Important therapeutic and preventative measures may result from mutational analysis in individuals with proteinuria and hematuria.
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Affiliation(s)
- David Schapiro
- Department of Medicine, Division of Nephrology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Ankana Daga
- Department of Medicine, Division of Nephrology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Jennifer A Lawson
- Department of Medicine, Division of Nephrology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Amar J Majmundar
- Department of Medicine, Division of Nephrology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Svjetlana Lovric
- Department of Medicine, Division of Nephrology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Weizhen Tan
- Department of Medicine, Division of Nephrology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Jillian K Warejko
- Department of Medicine, Division of Nephrology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Inés Fessi
- Department of Medicine, Division of Nephrology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Jia Rao
- Department of Medicine, Division of Nephrology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Merlin Airik
- Department of Medicine, Division of Nephrology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Heon Yung Gee
- Department of Medicine, Division of Nephrology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Ronen Schneider
- Department of Medicine, Division of Nephrology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Eugen Widmeier
- Department of Medicine, Division of Nephrology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Tobias Hermle
- Department of Medicine, Division of Nephrology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Shazia Ashraf
- Department of Medicine, Division of Nephrology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Tilman Jobst-Schwan
- Department of Medicine, Division of Nephrology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Amelie T van der Ven
- Department of Medicine, Division of Nephrology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Makiko Nakayama
- Department of Medicine, Division of Nephrology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Shirlee Shril
- Department of Medicine, Division of Nephrology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Daniela A Braun
- Department of Medicine, Division of Nephrology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Friedhelm Hildebrandt
- Department of Medicine, Division of Nephrology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
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Barger SR, James ML, Pellenz CD, Krendel M, Sirotkin V. Human myosin 1e tail but not motor domain replaces fission yeast Myo1 domains to support myosin-I function during endocytosis. Exp Cell Res 2019; 384:111625. [PMID: 31542284 DOI: 10.1016/j.yexcr.2019.111625] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Revised: 09/13/2019] [Accepted: 09/15/2019] [Indexed: 10/26/2022]
Abstract
In both unicellular and multicellular organisms, long-tailed class I myosins function in clathrin-mediated endocytosis. Myosin 1e (Myo1e) in vertebrates and Myo1 in fission yeast have similar domain organization, yet whether these proteins or their individual protein domains are functionally interchangeable remains unknown. In an effort to assess functional conservation of class I myosins, we tested whether human Myo1e could replace Myo1 in fission yeast Schizosaccharomyces pombe and found that it was unable to substitute for yeast Myo1. To determine if any individual protein domain is responsible for the inability of Myo1e to function in yeast, we created human-yeast myosin-I chimeras. By functionally testing these chimeric myosins in vivo, we concluded that the Myo1e motor domain is unable to function in yeast, even when combined with the yeast Myo1 tail and a full complement of yeast regulatory light chains. Conversely, the Myo1e tail, when attached to the yeast Myo1 motor domain, supports localization to endocytic actin patches and partially rescues the endocytosis defect in myo1Δ cells. Further dissection showed that both the TH1 and TH2-SH3 domains in the human Myo1e tail are required for localization and function of chimeric myosin-I at endocytic sites. Overall, this study provides insights into the role of individual myosin-I domains, expands the utility of fission yeast as a simple model system to study the effects of disease-associated MYO1E mutations, and supports a model of co-evolution between a myosin motor and its actin track.
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Affiliation(s)
- Sarah R Barger
- Department of Cell and Developmental Biology, State University of New York Upstate Medical University, Syracuse, NY, 13210, USA
| | - Michael L James
- Department of Cell and Developmental Biology, State University of New York Upstate Medical University, Syracuse, NY, 13210, USA
| | - Christopher D Pellenz
- Department of Cell and Developmental Biology, State University of New York Upstate Medical University, Syracuse, NY, 13210, USA
| | - Mira Krendel
- Department of Cell and Developmental Biology, State University of New York Upstate Medical University, Syracuse, NY, 13210, USA.
| | - Vladimir Sirotkin
- Department of Cell and Developmental Biology, State University of New York Upstate Medical University, Syracuse, NY, 13210, USA.
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Kampf LL, Schneider R, Gerstner L, Thünauer R, Chen M, Helmstädter M, Amar A, Onuchic-Whitford AC, Loza Munarriz R, Berdeli A, Müller D, Schrezenmeier E, Budde K, Mane S, Laricchia KM, Rehm HL, MacArthur DG, Lifton RP, Walz G, Römer W, Bergmann C, Hildebrandt F, Hermle T. TBC1D8B Mutations Implicate RAB11-Dependent Vesicular Trafficking in the Pathogenesis of Nephrotic Syndrome. J Am Soc Nephrol 2019; 30:2338-2353. [PMID: 31732614 DOI: 10.1681/asn.2019040414] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Accepted: 08/07/2019] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND Mutations in about 50 genes have been identified as monogenic causes of nephrotic syndrome, a frequent cause of CKD. These genes delineated the pathogenetic pathways and rendered significant insight into podocyte biology. METHODS We used whole-exome sequencing to identify novel monogenic causes of steroid-resistant nephrotic syndrome (SRNS). We analyzed the functional significance of an SRNS-associated gene in vitro and in podocyte-like Drosophila nephrocytes. RESULTS We identified hemizygous missense mutations in the gene TBC1D8B in five families with nephrotic syndrome. Coimmunoprecipitation assays indicated interactions between TBC1D8B and active forms of RAB11. Silencing TBC1D8B in HEK293T cells increased basal autophagy and exocytosis, two cellular functions that are independently regulated by RAB11. This suggests that TBC1D8B plays a regulatory role by inhibiting endogenous RAB11. Coimmunoprecipitation assays showed TBC1D8B also interacts with the slit diaphragm protein nephrin, and colocalizes with it in immortalized cell lines. Overexpressed murine Tbc1d8b with patient-derived mutations had lower affinity for endogenous RAB11 and nephrin compared with wild-type Tbc1d8b protein. Knockdown of Tbc1d8b in Drosophila impaired function of the podocyte-like nephrocytes, and caused mistrafficking of Sns, the Drosophila ortholog of nephrin. Expression of Rab11 RNAi in nephrocytes entailed defective delivery of slit diaphragm protein to the membrane, whereas RAB11 overexpression revealed a partial phenotypic overlap to Tbc1d8b loss of function. CONCLUSIONS Novel mutations in TBC1D8B are monogenic causes of SRNS. This gene inhibits RAB11. Our findings suggest that RAB11-dependent vesicular nephrin trafficking plays a role in the pathogenesis of nephrotic syndrome.
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Affiliation(s)
- Lina L Kampf
- Renal Division, Department of Medicine, Faculty of Medicine and Medical Center, University of Freiburg, Freiburg, Germany
| | - Ronen Schneider
- Division of Nephrology, Department of Pediatrics, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Lea Gerstner
- Renal Division, Department of Medicine, Faculty of Medicine and Medical Center, University of Freiburg, Freiburg, Germany
| | - Roland Thünauer
- Signalling Research Centres BIOSS and CIBSS and Faculty of Biology, University of Freiburg, Freiburg, Germany.,Advanced Light and Fluorescence Microscopy Facility, Centre for Structural Systems Biology (CSSB) and University of Hamburg, Hamburg, Germany
| | - Mengmeng Chen
- Renal Division, Department of Medicine, Faculty of Medicine and Medical Center, University of Freiburg, Freiburg, Germany
| | - Martin Helmstädter
- Renal Division, Department of Medicine, Faculty of Medicine and Medical Center, University of Freiburg, Freiburg, Germany
| | - Ali Amar
- Division of Nephrology, Department of Pediatrics, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Ana C Onuchic-Whitford
- Division of Nephrology, Department of Pediatrics, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts.,Renal Division, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts
| | | | - Afig Berdeli
- Department of Pediatrics, Molecular Medicine Laboratory, Ege University, Izmir, Turkey
| | - Dominik Müller
- Department of Pediatric Nephrology, Charité Universitätsmedizin Berlin, Berlin, Germany
| | - Eva Schrezenmeier
- Department of Nephrology and Medical Intensive Care, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Klemens Budde
- Department of Nephrology and Medical Intensive Care, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Shrikant Mane
- Department of Genetics, Yale University School of Medicine, New Haven, Connecticut
| | - Kristen M Laricchia
- Broad Center for Mendelian Genomics, Broad Institute of Massachusetts Institute of Technology and Harvard, Cambridge
| | - Heidi L Rehm
- Broad Center for Mendelian Genomics, Broad Institute of Massachusetts Institute of Technology and Harvard, Cambridge
| | - Daniel G MacArthur
- Broad Center for Mendelian Genomics, Broad Institute of Massachusetts Institute of Technology and Harvard, Cambridge
| | - Richard P Lifton
- Department of Genetics, Yale University School of Medicine, New Haven, Connecticut.,Laboratory of Human Genetics and Genomics, The Rockefeller University, New York, New York
| | - Gerd Walz
- Renal Division, Department of Medicine, Faculty of Medicine and Medical Center, University of Freiburg, Freiburg, Germany
| | - Winfried Römer
- Signalling Research Centres BIOSS and CIBSS and Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Carsten Bergmann
- Center for Human Genetics, Mainz, Germany.,Center for Human Genetics, Bioscientia, Ingelheim, Germany; and.,Department of Medicine, University Hospital Freiburg, Freiburg, Germany
| | - Friedhelm Hildebrandt
- Division of Nephrology, Department of Pediatrics, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts;
| | - Tobias Hermle
- Renal Division, Department of Medicine, Faculty of Medicine and Medical Center, University of Freiburg, Freiburg, Germany;
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Watts JA, Burdick J, Daigneault J, Zhu Z, Grunseich C, Bruzel A, Cheung VG. cis Elements that Mediate RNA Polymerase II Pausing Regulate Human Gene Expression. Am J Hum Genet 2019; 105:677-688. [PMID: 31495490 PMCID: PMC6817524 DOI: 10.1016/j.ajhg.2019.08.003] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2019] [Accepted: 08/09/2019] [Indexed: 12/11/2022] Open
Abstract
Aberrant gene expression underlies many human diseases. RNA polymerase II (Pol II) pausing is a key regulatory step in transcription. Here, we mapped the locations of RNA Pol II in normal human cells and found that RNA Pol II pauses in a consistent manner across individuals and cell types. At more than 1,000 genes including MYO1E and SESN2, RNA Pol II pauses at precise nucleotide locations. Characterization of these sites shows that RNA Pol II pauses at GC-rich regions that are marked by a sequence motif. Sixty-five percent of the pause sites are cytosines. By differential allelic gene expression analysis, we showed in our samples and a population dataset from the Genotype-Tissue Expression (GTEx) consortium that genes with more paused polymerase have lower expression levels. Furthermore, mutagenesis of the pause sites led to a significant increase in promoter activities. Thus, our data uncover that RNA Pol II pauses precisely at sites with distinct sequence features that in turn regulate gene expression.
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Affiliation(s)
- Jason A Watts
- Department of Internal Medicine, Division of Nephrology, University of Michigan, Ann Arbor, MI, USA
| | | | | | - Zhengwei Zhu
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA
| | - Christopher Grunseich
- National Institute of Neurological Disorders and Stroke, National Institute of Health, Bethesda, MD, USA
| | - Alan Bruzel
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA
| | - Vivian G Cheung
- Howard Hughes Medical Institute, Chevy Chase, MD, USA; Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA; Department of Pediatrics, Division of Neurology, University of Michigan, Ann Arbor, MI, USA.
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Guaragna MS, de Brito Lutaif ACG, de Souza ML, Maciel-Guerra AT, Belangero VMS, Guerra-Júnior G, de Mello MP. Promises and pitfalls of whole-exome sequencing exemplified by a nephrotic syndrome family. Mol Genet Genomics 2019; 295:135-142. [PMID: 31520189 DOI: 10.1007/s00438-019-01609-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2019] [Accepted: 09/05/2019] [Indexed: 01/12/2023]
Abstract
High-throughput techniques such as whole-exome sequencing (WES) show promise for the identification of candidate genes that underlie Mendelian diseases such as nephrotic syndrome (NS). These techniques have enabled the identification of a proportion of the approximately 54 genes associated with NS. However, the main pitfall of using WES in clinical and research practice is the identification of multiple variants, which hampers interpretation during downstream analysis. One useful strategy is to evaluate the co-inheritance of rare variants in affected family members. Here, we performed WES of a patient with steroid-resistant NS (SRNS) and intermittent microhematuria. Currently, 15 years after kidney transplantation, this patient presents normal kidney function. The patient was found to be homozygous for a rare MYO1E stop-gain variant, and was heterozygous for rare variants in NS-associated genes, COL4A4, KANK1, LAMB2, ANLN, E2F3, and APOL1. We evaluated the presence or absence of these variants in both parents and 11 siblings, three of whom exhibited a milder phenotype of the kidney disease. Analysis of variant segregation in the family, indicated the MYO1E stop-gain variant as the putative causal variant underlying the kidney disease in the patient and two of her affected sisters. Two secondary variants in COL4A4-identified in some other affected family members-require further functional studies to determine whether they play a role in the development of microhematuria in affected family members. Our data illustrate the difficulties in distinguishing the causal pathogenic variants from incidental findings after WES-based variant analysis, especially in heterogenous genetic conditions, such as NS.
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Affiliation(s)
- Mara Sanches Guaragna
- Laboratory of Human Molecular Genetics, Center for Molecular Biology and Genetic Engineering (CBMEG), State University of Campinas, UNICAMP, Caixa Postal 6010, 13083-875, Campinas, SP, Brazil.
| | - Anna Cristina Gervásio de Brito Lutaif
- Integrated Center of Pediatric Nephrology (CIN), Department of Pediatrics, School of Medical Sciences (FCM), State University of Campinas, UNICAMP, Campinas, Brazil
| | - Marcela Lopes de Souza
- Laboratory of Human Molecular Genetics, Center for Molecular Biology and Genetic Engineering (CBMEG), State University of Campinas, UNICAMP, Caixa Postal 6010, 13083-875, Campinas, SP, Brazil
| | | | - Vera Maria Santoro Belangero
- Integrated Center of Pediatric Nephrology (CIN), Department of Pediatrics, School of Medical Sciences (FCM), State University of Campinas, UNICAMP, Campinas, Brazil.,Department of Pediatrics, School of Medical Sciences (FCM), UNICAMP, Campinas, SP, Brazil
| | - Gil Guerra-Júnior
- Department of Pediatrics, School of Medical Sciences (FCM), UNICAMP, Campinas, SP, Brazil.,Growth and Development Laboratory, Center for Investigation in Pediatrics (CIPED), School of Medical Sciences (FCM), UNICAMP, Campinas, SP, Brazil
| | - Maricilda Palandi de Mello
- Laboratory of Human Molecular Genetics, Center for Molecular Biology and Genetic Engineering (CBMEG), State University of Campinas, UNICAMP, Caixa Postal 6010, 13083-875, Campinas, SP, Brazil
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A bigenic mouse model of FSGS reveals perturbed pathways in podocytes, mesangial cells and endothelial cells. PLoS One 2019; 14:e0216261. [PMID: 31461442 PMCID: PMC6713350 DOI: 10.1371/journal.pone.0216261] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Accepted: 08/12/2019] [Indexed: 11/24/2022] Open
Abstract
Focal segmental glomerulosclerosis is a major cause of end stage renal disease. Many patients prove unresponsive to available therapies. An improved understanding of the molecular basis of the disease process could provide insights leading to novel therapeutic approaches. In this study we carried out an RNA-seq analysis of the altered gene expression patterns of podocytes, mesangial cells and glomerular endothelial cells of the bigenic Cd2ap+/-, Fyn-/- mutant mouse model of FSGS. In the podocytes we observed upregulation of many genes related to the Tgfβ family/pathway, including Gdnf, Tgfβ1, Tgfβ2, Snai2, Vegfb, Bmp4, and Tnc. The mutant podocytes also showed upregulation of Acta2, a marker of smooth muscle and associated with myofibroblasts, which are implicated in driving fibrosis. GO analysis of the podocyte upregulated genes identified elevated protein kinase activity, increased expression of growth factors, and negative regulation of cell adhesion, perhaps related to the observed podocyte loss. Both podocytes and mesangial cells showed strong upregulation of aldehyde dehydrogenase genes involved in the synthesis of retinoic acid. Similarly, the Cd2ap+/-, Fyn-/- mesangial cells, as well as podocytes in other genetic models, and the glomeruli of human FSGS patients, all show upregulation of the serine protease Prss23, with the common thread suggesting important functionality. Another gene with strong upregulation in the Cd2ap+/-, Fyn-/- mutant mesangial cells as well as multiple other mutant mouse models of FSGS was thrombospondin, which activates the secreted inactive form of Tgfβ. The Cd2ap+/-, Fyn-/- mutant endothelial cells showed elevated expression of genes involved in cell proliferation, angioblast migration, angiogenesis, and neovasculature, all consistent with the formation of new blood vessels in the diseased glomerulus. The resulting global definition of the perturbed molecular pathways in the three major cell types of the mutant glomerulus provide deeper understanding of the molecular pathogenic pathways.
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