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Bannell TAK, Cockburn JJB. The molecular structure and function of fibrocystin, the key gene product implicated in autosomal recessive polycystic kidney disease (ARPKD). Ann Hum Genet 2024; 88:58-75. [PMID: 37905714 DOI: 10.1111/ahg.12535] [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: 07/11/2023] [Revised: 09/14/2023] [Accepted: 10/03/2023] [Indexed: 11/02/2023]
Abstract
Autosomal recessive polycystic kidney disease is an early onset inherited hepatorenal disorder affecting around 1 in 20,000 births with no approved specific therapies. The disease is almost always caused by variations in the polycystic kidney and hepatic disease 1 gene, which encodes fibrocystin (FC), a very large, single-pass transmembrane glycoprotein found in primary cilia, urine and urinary exosomes. By comparison to proteins involved in autosomal dominant PKD, our structural and molecular understanding of FC has lagged far behind such that there are no published experimentally determined structures of any part of the protein. Bioinformatics analyses predict that the ectodomain contains a long chain of immunoglobulin-like plexin-transcription factor domains, a protective antigen 14 domain, a tandem G8-TMEM2 homology region and a sperm protein, enterokinase and agrin domain. Here we review current knowledge on the molecular function of the protein from a structural perspective.
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Affiliation(s)
- Travis A K Bannell
- Astbury Centre for Structural and Molecular Biology, University of Leeds, Leeds, UK
- School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, UK
| | - Joseph J B Cockburn
- Astbury Centre for Structural and Molecular Biology, University of Leeds, Leeds, UK
- School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, UK
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2
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Harafuji N, Yang C, Wu M, Thiruvengadam G, Gordish-Dressman H, Thompson RG, Bell PD, Rosenberg AZ, Dafinger C, Liebau MC, Bebok Z, Caldovic L, Guay-Woodford LM. Differential regulation of MYC expression by PKHD1/Pkhd1 in human and mouse kidneys: phenotypic implications for recessive polycystic kidney disease. Front Cell Dev Biol 2023; 11:1270980. [PMID: 38125876 PMCID: PMC10731465 DOI: 10.3389/fcell.2023.1270980] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Accepted: 10/30/2023] [Indexed: 12/23/2023] Open
Abstract
Autosomal recessive polycystic kidney disease (ARPKD; MIM#263200) is a severe, hereditary, hepato-renal fibrocystic disorder that leads to early childhood morbidity and mortality. Typical forms of ARPKD are caused by pathogenic variants in the PKHD1 gene, which encodes the fibrocystin/polyductin (FPC) protein. MYC overexpression has been proposed as a driver of renal cystogenesis, but little is known about MYC expression in recessive PKD. In the current study, we provide the first evidence that MYC is overexpressed in kidneys from ARPKD patients and confirm that MYC is upregulated in cystic kidneys from cpk mutant mice. In contrast, renal MYC expression levels were not altered in several Pkhd1 mutant mice that lack a significant cystic kidney phenotype. We leveraged previous observations that the carboxy-terminus of mouse FPC (FPC-CTD) is proteolytically cleaved through Notch-like processing, translocates to the nucleus, and binds to double stranded DNA, to examine whether the FPC-CTD plays a role in regulating MYC/Myc transcription. Using immunofluorescence, reporter gene assays, and ChIP, we demonstrate that both human and mouse FPC-CTD can localize to the nucleus, bind to the MYC/Myc P1 promoter, and activate MYC/Myc expression. Interestingly, we observed species-specific differences in FPC-CTD intracellular trafficking. Furthermore, our informatic analyses revealed limited sequence identity of FPC-CTD across vertebrate phyla and database queries identified temporal differences in PKHD1/Pkhd1 and CYS1/Cys1 expression patterns in mouse and human kidneys. Given that cystin, the Cys1 gene product, is a negative regulator of Myc transcription, these temporal differences in gene expression could contribute to the relative renoprotection from cystogenesis in Pkhd1-deficient mice. Taken together, our findings provide new mechanistic insights into differential mFPC-CTD and hFPC-CTD regulation of MYC expression in renal epithelial cells, which may illuminate the basis for the phenotypic disparities between human patients with PKHD1 pathogenic variants and Pkhd1-mutant mice.
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Affiliation(s)
- Naoe Harafuji
- Center for Translational Research, Children’s National Hospital, Washington, DC, United States
| | - Chaozhe Yang
- Center for Translational Research, Children’s National Hospital, Washington, DC, United States
| | - Maoqing Wu
- Center for Translational Research, Children’s National Hospital, Washington, DC, United States
| | - Girija Thiruvengadam
- Center for Translational Research, Children’s National Hospital, Washington, DC, United States
| | | | - R. Griffin Thompson
- Heersink School of Medicine, The University of Alabama at Birmingham, Birmingham, AL, United States
| | - P. Darwin Bell
- Heersink School of Medicine, The University of Alabama at Birmingham, Birmingham, AL, United States
| | - Avi Z. Rosenberg
- Department of Pathology, Johns Hopkins University, Baltimore, MD, United States
| | - Claudia Dafinger
- Department of Pediatrics and Center for Molecular Medicine, Medical Faculty and University Hospital Cologne, University of Cologne, Cologne, Germany
| | - Max C. Liebau
- Department of Pediatrics, Center for Family Health, Center for Rare Diseases and Center for Molecular Medicine, Medical Faculty and University Hospital Cologne, University of Cologne, Cologne, Germany
| | - Zsuzsanna Bebok
- Heersink School of Medicine, The University of Alabama at Birmingham, Birmingham, AL, United States
| | - Ljubica Caldovic
- Center for Genetic Medicine Research, Children’s National Hospital, Washington, DC, United States
- Department of Genomics and Precision Medicine, School of Medical and Health Sciences, The George Washington University, Washington, DC, United States
| | - Lisa M. Guay-Woodford
- Center for Translational Research, Children’s National Hospital, Washington, DC, United States
- Center for Genetic Medicine Research, Children’s National Hospital, Washington, DC, United States
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3
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Walker RV, Yao Q, Xu H, Maranto A, Swaney KF, Ramachandran S, Li R, Cassina L, Polster BM, Outeda P, Boletta A, Watnick T, Qian F. Fibrocystin/Polyductin releases a C-terminal fragment that translocates into mitochondria and suppresses cystogenesis. Nat Commun 2023; 14:6513. [PMID: 37845212 PMCID: PMC10579373 DOI: 10.1038/s41467-023-42196-4] [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: 08/31/2022] [Accepted: 10/03/2023] [Indexed: 10/18/2023] Open
Abstract
Fibrocystin/Polyductin (FPC), encoded by PKHD1, is associated with autosomal recessive polycystic kidney disease (ARPKD), yet its precise role in cystogenesis remains unclear. Here we show that FPC undergoes complex proteolytic processing in developing kidneys, generating three soluble C-terminal fragments (ICDs). Notably, ICD15, contains a novel mitochondrial targeting sequence at its N-terminus, facilitating its translocation into mitochondria. This enhances mitochondrial respiration in renal epithelial cells, partially restoring impaired mitochondrial function caused by FPC loss. FPC inactivation leads to abnormal ultrastructural morphology of mitochondria in kidney tubules without cyst formation. Moreover, FPC inactivation significantly exacerbates renal cystogenesis and triggers severe pancreatic cystogenesis in a Pkd1 mouse mutant Pkd1V/V in which cleavage of Pkd1-encoded Polycystin-1 at the GPCR Proteolysis Site is blocked. Deleting ICD15 enhances renal cystogenesis without inducing pancreatic cysts in Pkd1V/V mice. These findings reveal a direct link between FPC and a mitochondrial pathway through ICD15 cleavage, crucial for cystogenesis mechanisms.
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Affiliation(s)
- Rebecca V Walker
- Division of Nephrology, Department of Medicine, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Qin Yao
- Division of Nephrology, Department of Medicine, University of Maryland School of Medicine, Baltimore, MD, USA
- Laboratory of Clinical Investigation, National Institute on Aging, National Institutes of Health, Baltimore, MD, USA
| | - Hangxue Xu
- Division of Nephrology, Department of Medicine, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Anthony Maranto
- Division of Nephrology, Department of Medicine, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Kristen F Swaney
- Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Sreekumar Ramachandran
- Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Rong Li
- Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Mechanobiology Institute and Department of Biological Sciences, National University of Singapore, Singapore, 117411, Singapore
| | - Laura Cassina
- Division of Genetics and Cell Biology, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Brian M Polster
- Department of Anesthesiology and Center for Shock, Trauma, and Anesthesiology Research, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Patricia Outeda
- Division of Nephrology, Department of Medicine, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Alessandra Boletta
- Division of Genetics and Cell Biology, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Terry Watnick
- Division of Nephrology, Department of Medicine, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Feng Qian
- Division of Nephrology, Department of Medicine, University of Maryland School of Medicine, Baltimore, MD, USA.
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Ishimoto Y, Menezes LF, Zhou F, Yoshida T, Komori T, Qiu J, Young MF, Lu H, Potapova S, Outeda P, Watnick T, Germino GG. A novel ARPKD mouse model with near-complete deletion of the Polycystic Kidney and Hepatic Disease 1 (Pkhd1) genomic locus presents with multiple phenotypes but not renal cysts. Kidney Int 2023; 104:611-616. [PMID: 37419448 PMCID: PMC10529617 DOI: 10.1016/j.kint.2023.05.027] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Revised: 05/04/2023] [Accepted: 05/26/2023] [Indexed: 07/09/2023]
Affiliation(s)
- Yu Ishimoto
- Polycystic Kidney Disease Section, Kidney Disease Branch, National Institute of Diabetes and Digestive and Kidney Disease (NIDDK), National Institutes of Health (NIH), Bethesda, Maryland, USA
| | - Luis F Menezes
- Polycystic Kidney Disease Section, Kidney Disease Branch, National Institute of Diabetes and Digestive and Kidney Disease (NIDDK), National Institutes of Health (NIH), Bethesda, Maryland, USA.
| | - Fang Zhou
- Polycystic Kidney Disease Section, Kidney Disease Branch, National Institute of Diabetes and Digestive and Kidney Disease (NIDDK), National Institutes of Health (NIH), Bethesda, Maryland, USA
| | - Teruhiko Yoshida
- Polycystic Kidney Disease Section, Kidney Disease Branch, National Institute of Diabetes and Digestive and Kidney Disease (NIDDK), National Institutes of Health (NIH), Bethesda, Maryland, USA
| | - Taishi Komori
- Molecular Biology of Bones and Teeth Section, Department of Health and Human Services (DHHS), National Institutes of Dental and Craniofacial Research (NIDCR), National Institutes of Health (NIH), Bethesda, Maryland, USA
| | - Jiahe Qiu
- Polycystic Kidney Disease Section, Kidney Disease Branch, National Institute of Diabetes and Digestive and Kidney Disease (NIDDK), National Institutes of Health (NIH), Bethesda, Maryland, USA
| | - Marian F Young
- Molecular Biology of Bones and Teeth Section, Department of Health and Human Services (DHHS), National Institutes of Dental and Craniofacial Research (NIDCR), National Institutes of Health (NIH), Bethesda, Maryland, USA
| | - Huiyan Lu
- Mouse Transgenic Core Facility, National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), National Institutes of Health (NIH), Bethesda, Maryland, USA
| | - Svetlana Potapova
- Mouse Transgenic Core Facility, National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), National Institutes of Health (NIH), Bethesda, Maryland, USA
| | - Patricia Outeda
- Division of Nephrology, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Terry Watnick
- Division of Nephrology, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Gregory G Germino
- Polycystic Kidney Disease Section, Kidney Disease Branch, National Institute of Diabetes and Digestive and Kidney Disease (NIDDK), National Institutes of Health (NIH), Bethesda, Maryland, USA.
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Yang C, Harafuji N, Caldovic L, Yu W, Boddu R, Bhattacharya S, Barseghyan H, Gordish-Dressman H, Foreman O, Bebok Z, Eicher EM, Guay-Woodford LM. Pkhd1 cyli/cyli mice have altered renal Pkhd1 mRNA processing and hormonally sensitive liver disease. J Mol Med (Berl) 2023; 101:1141-1151. [PMID: 37584738 PMCID: PMC10482757 DOI: 10.1007/s00109-023-02351-2] [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] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Revised: 06/30/2023] [Accepted: 07/12/2023] [Indexed: 08/17/2023]
Abstract
Autosomal-recessive polycystic kidney disease (ARPKD; MIM #263200) is a severe, hereditary, hepato-renal fibrocystic disorder that causes early childhood morbidity and mortality. Mutations in the polycystic kidney and hepatic disease 1 (PKHD1) gene, which encodes the protein fibrocystin/polyductin complex (FPC), cause all typical forms of ARPKD. Several mouse lines carrying diverse, genetically engineered disruptions in the orthologous Pkhd1 gene have been generated, but none expresses the classic ARPKD renal phenotype. In the current study, we characterized a spontaneous mouse Pkhd1 mutation that is transmitted as a recessive trait and causes cysticliver (cyli), similar to the hepato-biliary disease in ARPKD, but which is exacerbated by age, sex, and parity. We mapped the mutation to Chromosome 1 and determined that an insertion/deletion mutation causes a frameshift within Pkhd1 exon 48, which is predicted to result in a premature termination codon (UGA). Pkhd1cyli/cyli (cyli) mice exhibit a severe liver pathology but lack renal disease. Further analysis revealed that several alternatively spliced Pkhd1 mRNA, all containing exon 48, were expressed in cyli kidneys, but in lower abundance than in wild-type kidneys, suggesting that these transcripts escaped from nonsense-mediated decay (NMD). We identified an AAAAAT motif in exon 48 upstream of the cyli mutation which could enable ribosomal frameshifting, thus potentially allowing production of sufficient amounts of FPC for renoprotection. This mechanism, expressed in a species-specific fashion, may help explain the disparities in the renal phenotype observed between Pkhd1 mutant mice and patients with PKHD1-related disease. KEY MESSAGES: The Pkhd1cyli/cyli mouse expresses cystic liver disease, but no kidney phenotype. Pkhd1 mRNA expression is decreased in cyli liver and kidneys compared to wild-type. Ribosomal frameshifting may be responsible for Pkhd1 mRNA escape from NMD. Pkhd1 mRNA escape from NMD could contribute to the absent kidney phenotype.
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Affiliation(s)
- Chaozhe Yang
- Center for Translational Research, Children's National Research Institute, Washington, DC, 20010, USA
| | - Naoe Harafuji
- Center for Translational Research, Children's National Research Institute, Washington, DC, 20010, USA
| | - Ljubica Caldovic
- Center for Genetic Medicine Research, Children's National Research Institute, Washington, DC, 20010, USA
- Department of Genomics and Precision Medicine, The George Washington University School of Medicine and Health Sciences, Washington, DC, 20037, USA
| | - Weiying Yu
- Center for Translational Research, Children's National Research Institute, Washington, DC, 20010, USA
| | - Ravindra Boddu
- Division of Nephrology, Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, 35294, USA
- Department of Pharmacology & Cancer Biology, Duke University School of Medicine, Durham, NC, 27710, USA
| | - Surajit Bhattacharya
- Center for Genetic Medicine Research, Children's National Research Institute, Washington, DC, 20010, USA
| | - Hayk Barseghyan
- Center for Genetic Medicine Research, Children's National Research Institute, Washington, DC, 20010, USA
- Department of Genomics and Precision Medicine, The George Washington University School of Medicine and Health Sciences, Washington, DC, 20037, USA
| | - Heather Gordish-Dressman
- Center for Translational Research, Children's National Research Institute, Washington, DC, 20010, USA
| | - Oded Foreman
- Genentech USA, Inc, South San Francisco, CA, 94080, USA
- Cell Developmental and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL, 35294, USA
| | - Zsuzsa Bebok
- Cell Developmental and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL, 35294, USA
| | - Eva M Eicher
- The Jackson Laboratory, Bar Harbor, ME, 04609, USA
| | - Lisa M Guay-Woodford
- Center for Translational Research, Children's National Research Institute, Washington, DC, 20010, USA.
- Center for Genetic Medicine Research, Children's National Research Institute, Washington, DC, 20010, USA.
- Children's Hospital of Philadelphia, Philadelphia, USA.
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Clearman KR, Haycraft CJ, Croyle MJ, Collawn JF, Yoder BK. Functions of the primary cilium in the kidney and its connection with renal diseases. Curr Top Dev Biol 2023; 155:39-94. [PMID: 38043952 DOI: 10.1016/bs.ctdb.2023.07.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/05/2023]
Abstract
The nonmotile primary cilium is a sensory structure found on most mammalian cell types that integrates multiple signaling pathways involved in tissue development and postnatal function. As such, mutations disrupting cilia activities cause a group of disorders referred to as ciliopathies. These disorders exhibit a wide spectrum of phenotypes impacting nearly every tissue. In the kidney, primary cilia dysfunction caused by mutations in polycystin 1 (Pkd1), polycystin 2 (Pkd2), or polycystic kidney and hepatic disease 1 (Pkhd1), result in polycystic kidney disease (PKD), a progressive disorder causing renal functional decline and end-stage renal disease. PKD affects nearly 1 in 1000 individuals and as there is no cure for PKD, patients frequently require dialysis or renal transplantation. Pkd1, Pkd2, and Pkhd1 encode membrane proteins that all localize in the cilium. Pkd1 and Pkd2 function as a nonselective cation channel complex while Pkhd1 protein function remains uncertain. Data indicate that the cilium may act as a mechanosensor to detect fluid movement through renal tubules. Other functions proposed for the cilium and PKD proteins in cyst development involve regulation of cell cycle and oriented division, regulation of renal inflammation and repair processes, maintenance of epithelial cell differentiation, and regulation of mitochondrial structure and metabolism. However, how loss of cilia or cilia function leads to cyst development remains elusive. Studies directed at understanding the roles of Pkd1, Pkd2, and Pkhd1 in the cilium and other locations within the cell will be important for developing therapeutic strategies to slow cyst progression.
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Affiliation(s)
- Kelsey R Clearman
- Department of Cell, Developmental, and Integrative Biology, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Courtney J Haycraft
- Department of Cell, Developmental, and Integrative Biology, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Mandy J Croyle
- Department of Cell, Developmental, and Integrative Biology, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
| | - James F Collawn
- Department of Cell, Developmental, and Integrative Biology, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Bradley K Yoder
- Department of Cell, Developmental, and Integrative Biology, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States.
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Zhang YJ, Yang C, Wang W, Harafuji N, Stasiak P, Bell PD, Caldovic L, Sztul E, Guay-Woodford LM, Bebok Z. Cystin is required for maintaining fibrocystin (FPC) levels and safeguarding proteome integrity in mouse renal epithelial cells: A mechanistic connection between the kidney defects in cpk mice and human ARPKD. FASEB J 2023; 37:e23008. [PMID: 37318790 DOI: 10.1096/fj.202300100r] [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: 01/20/2023] [Revised: 05/15/2023] [Accepted: 05/19/2023] [Indexed: 06/16/2023]
Abstract
Autosomal recessive polycystic kidney disease (ARPKD) is caused primarily by mutations in PKHD1, encoding fibrocystin (FPC), but Pkhd1 mutant mice failed to reproduce the human phenotype. In contrast, the renal lesion in congenital polycystic kidney (cpk) mice, with a mutation in Cys1 and cystin protein loss, closely phenocopies ARPKD. Although the nonhomologous mutation diminished the translational relevance of the cpk model, recent identification of patients with CYS1 mutations and ARPKD prompted the investigations described herein. We examined cystin and FPC expression in mouse models (cpk, rescued-cpk (r-cpk), Pkhd1 mutants) and mouse cortical collecting duct (CCD) cell lines (wild type (wt), cpk). We found that cystin deficiency caused FPC loss in both cpk kidneys and CCD cells. FPC levels increased in r-cpk kidneys and siRNA of Cys1 in wt cells reduced FPC. However, FPC deficiency in Pkhd1 mutants did not affect cystin levels. Cystin deficiency and associated FPC loss impacted the architecture of the primary cilium, but not ciliogenesis. No reduction in Pkhd1 mRNA levels in cpk kidneys and CCD cells suggested posttranslational FPC loss. Studies of cellular protein degradation systems suggested selective autophagy as a mechanism. In support of the previously described function of FPC in E3 ubiquitin ligase complexes, we demonstrated reduced polyubiquitination and elevated levels of functional epithelial sodium channel in cpk cells. Therefore, our studies expand the function of cystin in mice to include inhibition of Myc expression via interaction with necdin and maintenance of FPC as functional component of the NEDD4 E3 ligase complexes. Loss of FPC from E3 ligases may alter the cellular proteome, contributing to cystogenesis through multiple, yet to be defined, mechanisms.
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Affiliation(s)
- Yiming J Zhang
- Department of Cell Developmental and Integrative Biology (CDIB), University of Alabama at Birmingham, School of Medicine, Birmingham, Alabama, USA
| | - Chaozhe Yang
- Center for Translational Research, Children's National Hospital, Washington, District of Columbia, USA
| | - Wei Wang
- Cystic Fibrosis Research Center, University of Alabama at Birmingham, School of Medicine, Birmingham, Alabama, USA
| | - Naoe Harafuji
- Center for Translational Research, Children's National Hospital, Washington, District of Columbia, USA
| | - Piotr Stasiak
- Department of Cell Developmental and Integrative Biology (CDIB), University of Alabama at Birmingham, School of Medicine, Birmingham, Alabama, USA
| | - P Darwin Bell
- Department of Medicine, Division of Nephrology, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Ljubica Caldovic
- Center for Translational Research, Children's National Hospital, Washington, District of Columbia, USA
| | - Elizabeth Sztul
- Department of Cell Developmental and Integrative Biology (CDIB), University of Alabama at Birmingham, School of Medicine, Birmingham, Alabama, USA
| | - Lisa M Guay-Woodford
- Center for Translational Research, Children's National Hospital, Washington, District of Columbia, USA
- Center for Genetic Medicine Research, Children's National Hospital, Washington, District of Columbia, USA
| | - Zsuzsanna Bebok
- Department of Cell Developmental and Integrative Biology (CDIB), University of Alabama at Birmingham, School of Medicine, Birmingham, Alabama, USA
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A Potential Therapy Using Antisense Oligonucleotides to Treat Autosomal Recessive Polycystic Kidney Disease. J Clin Med 2023; 12:jcm12041428. [PMID: 36835961 PMCID: PMC9966971 DOI: 10.3390/jcm12041428] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2022] [Revised: 02/01/2023] [Accepted: 02/08/2023] [Indexed: 02/16/2023] Open
Abstract
(1) Background: Autosomal recessive polycystic kidney disease (ARPKD) is a rare ciliopathy characterized by progressively enlarged kidneys with fusiform dilatation of the collecting ducts. Loss-of-function mutations in the PKHD1 gene, which encodes fibrocystin/polyductin, cause ARPKD; however, an efficient treatment method and drug for ARPKD have yet to be found. Antisense oligonucleotides (ASOs) are short special oligonucleotides which function to regulate gene expression and alter mRNA splicing. Several ASOs have been approved by the FDA for the treatment of genetic disorders, and many are progressing at present. We designed ASOs to verify whether ASOs mediate the correction of splicing further to treat ARPKD arising from splicing defects and explored them as a potential treatment option. (2) Methods: We screened 38 children with polycystic kidney disease for gene detection using whole-exome sequencing (WES) and targeted next-generation sequencing. Their clinical information was investigated and followed up. The PKHD1 variants were summarized and analyzed, and association analysis was carried out to analyze the relationship between genotype and phenotype. Various bioinformatics tools were used to predict pathogenicity. Hybrid minigene analysis was performed as part of the functional splicing analysis. Moreover, the de novo protein synthesis inhibitor cycloheximide was selected to verify the degraded pathway of abnormal pre-mRNAs. ASOs were designed to rescue aberrant splicing, and this was verified. (3) Results: Of the 11 patients with PKHD1 variants, all of them exhibited variable levels of complications of the liver and kidneys. We found that patients with truncating variants and variants in certain regions had a more severe phenotype. Two splicing variants of the PKHD1 genotypes were studied via the hybrid minigene assay: variants c.2141-3T>C and c.11174+5G>A. These cause aberrant splicing, and their strong pathogenicity was confirmed. We demonstrated that the abnormal pre-mRNAs produced from the variants escaped from the NMD pathway with the use of the de novo protein synthesis inhibitor cycloheximide. Moreover, we found that the splicing defects were rescued by using ASOs, which efficiently induced the exclusion of pseudoexons. (4) Conclusion: Patients with truncating variants and variants in certain regions had a more severe phenotype. ASOs are a potential drug for treating ARPKD patients harboring splicing mutations of the PKHD1 gene by correcting the splicing defects and increasing the expression of the normal PKHD1 gene.
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9
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Fleischer LT, Ballester L, Dutt M, Howarth K, Poznick L, Darge K, Furth SL, Hartung EA. Evaluation of galectin-3 and intestinal fatty acid binding protein as serum biomarkers in autosomal recessive polycystic kidney disease. J Nephrol 2023; 36:133-145. [PMID: 35980535 DOI: 10.1007/s40620-022-01416-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Accepted: 07/27/2022] [Indexed: 02/07/2023]
Abstract
BACKGROUND Autosomal recessive polycystic kidney disease (ARPKD) causes fibrocystic kidney disease, congenital hepatic fibrosis, and portal hypertension. Serum galectin-3 (Gal-3) and intestinal fatty acid binding protein (I-FABP) are potential biomarkers of kidney fibrosis and portal hypertension, respectively. We examined whether serum Gal-3 associates with kidney disease severity and serum I-FABP associates with liver disease severity in ARPKD. METHODS Cross-sectional study of 29 participants with ARPKD (0.2-21 years old) and presence of native kidneys (Gal-3 analyses, n = 18) and/or native livers (I-FABP analyses, n = 21). Serum Gal-3 and I-FABP were analyzed using enzyme linked immunosorbent assay. Kidney disease severity variables included estimated glomerular filtration rate (eGFR) and height-adjusted total kidney volume (htTKV). Liver disease severity was characterized using ultrasound elastography to measure liver fibrosis, and spleen length and platelet count as markers of portal hypertension. Simple and multivariable linear regression examined associations between Gal-3 and kidney disease severity (adjusted for liver disease severity) and between I-FABP and liver disease severity (adjusted for eGFR). RESULTS Serum Gal-3 was negatively associated with eGFR; 1 standard deviation (SD) lower eGFR was associated with 0.795 SD higher Gal-3 level (95% CI - 1.116, - 0.473; p < 0.001). This association remained significant when adjusted for liver disease severity. Serum Gal-3 was not associated with htTKV in adjusted analyses. Overall I-FABP levels were elevated, but there were no linear associations between I-FABP and liver disease severity in unadjusted or adjusted models. CONCLUSIONS Serum Gal-3 is associated with eGFR in ARPKD, suggesting its value as a possible novel biomarker of kidney disease severity. We found no associations between serum I-FABP and ARPKD liver disease severity despite overall elevated I-FABP levels.
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Affiliation(s)
| | - Lance Ballester
- Biostatistics and Data Management Core, Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Mohini Dutt
- Division of Nephrology, Children's Hospital of Philadelphia, 3401 Civic Center Boulevard, Philadelphia, PA, 19104, USA
| | - Kathryn Howarth
- Division of Nephrology, Children's Hospital of Philadelphia, 3401 Civic Center Boulevard, Philadelphia, PA, 19104, USA
| | - Laura Poznick
- Department of Radiology, Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Kassa Darge
- Department of Radiology, Children's Hospital of Philadelphia, Philadelphia, PA, USA.,Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Susan L Furth
- Division of Nephrology, Children's Hospital of Philadelphia, 3401 Civic Center Boulevard, Philadelphia, PA, 19104, USA.,Department of Pediatrics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Erum A Hartung
- Division of Nephrology, Children's Hospital of Philadelphia, 3401 Civic Center Boulevard, Philadelphia, PA, 19104, USA. .,Department of Pediatrics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.
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10
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Stoyanova II, Lutz D. Functional Diversity of Neuronal Cell Adhesion and Recognition Molecule L1CAM through Proteolytic Cleavage. Cells 2022; 11:cells11193085. [PMID: 36231047 PMCID: PMC9562852 DOI: 10.3390/cells11193085] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2022] [Revised: 09/26/2022] [Accepted: 09/29/2022] [Indexed: 11/16/2022] Open
Abstract
The neuronal cell adhesion and recognition molecule L1 does not only 'keep cells together' by way of homophilic and heterophilic interactions, but can also promote cell motility when cleaved into fragments by several proteases. It has largely been thought that such fragments are signs of degradation. Now, it is clear that proteolysis contributes to the pronounced functional diversity of L1, which we have reviewed in this work. L1 fragments generated at the plasma membrane are released into the extracellular space, whereas other membrane-bound fragments are internalised and enter the nucleus, thus conveying extracellular signals to the cell interior. Post-translational modifications on L1 determine the sequence of cleavage by proteases and the subcellular localisation of the generated fragments. Inside the neuronal cells, L1 fragments interact with various binding partners to facilitate morphogenic events, as well as regenerative processes. The stimulation of L1 proteolysis via injection of L1 peptides or proteases active on L1 or L1 mimetics is a promising tool for therapy of injured nervous systems. The collective findings gathered over the years not only shed light on the great functional diversity of L1 and its fragments, but also provide novel mechanistic insights into the adhesion molecule proteolysis that is active in the developing and diseased nervous system.
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Affiliation(s)
- Irina I. Stoyanova
- Department of Anatomy and Cell Biology, Faculty of Medicine, Medical University, 9002 Varna, Bulgaria
- Department of Brain Ischemia Mechanisms, Research Institute, Medical University, 9002 Varna, Bulgaria
- Correspondence: (I.I.S.); (D.L.)
| | - David Lutz
- Department of Neuroanatomy and Molecular Brain Research, Ruhr University Bochum,
44801 Bochum, Germany
- Correspondence: (I.I.S.); (D.L.)
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11
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Goggolidou P, Richards T. The genetics of Autosomal Recessive Polycystic Kidney Disease (ARPKD). Biochim Biophys Acta Mol Basis Dis 2022; 1868:166348. [PMID: 35032595 DOI: 10.1016/j.bbadis.2022.166348] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2021] [Revised: 12/27/2021] [Accepted: 01/06/2022] [Indexed: 12/21/2022]
Abstract
ARPKD is a genetically inherited kidney disease that manifests by bilateral enlargement of cystic kidneys and liver fibrosis. It shows a range of severity, with 30% of individuals dying early on and the majority having good prognosis if they survive the first year of life. The reasons for this variability remain unclear. Two genes have been shown to cause ARPKD when mutated, PKHD1, mutations in which lead to most of ARPKD cases and DZIP1L, which is associated with moderate ARPKD. This mini review will explore the genetics of ARPKD and discuss potential genetic modifiers and phenocopies that could affect diagnosis.
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Affiliation(s)
- Paraskevi Goggolidou
- Faculty of Science and Engineering, University of Wolverhampton, Wulfruna Street, Wolverhampton WV1 1LY, UK.
| | - Taylor Richards
- Faculty of Science and Engineering, University of Wolverhampton, Wulfruna Street, Wolverhampton WV1 1LY, UK
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12
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Wu M, Harafuji N, O'Connor AK, Caldovic L, Guay-Woodford LM. Transcription factor Ap2b regulates the mouse autosomal recessive polycystic kidney disease genes, Pkhd1 and Cys1. Front Mol Biosci 2022; 9:946344. [PMID: 36710876 PMCID: PMC9877354 DOI: 10.3389/fmolb.2022.946344] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Accepted: 12/29/2022] [Indexed: 01/14/2023] Open
Abstract
Transcription factor Ap2b (TFAP2B), an AP-2 family transcription factor, binds to the palindromic consensus DNA sequence, 5'-GCCN3-5GGC-3'. Mice lacking functional Tfap2b gene die in the perinatal or neonatal period with cystic dilatation of the kidney distal tubules and collecting ducts, a phenotype resembling autosomal recessive polycystic kidney disease (ARPKD). Human ARPKD is caused by mutations in PKHD1, DZIP1L, and CYS1, which are conserved in mammals. In this study, we examined the potential role of TFAP2B as a common regulator of Pkhd1 and Cys1. We determined the transcription start site (TSS) of Cys1 using 5' Rapid Amplification of cDNA Ends (5'RACE); the TSS of Pkhd1 has been previously established. Bioinformatic approaches identified cis-regulatory elements, including two TFAP2B consensus binding sites, in the upstream regulatory regions of both Pkhd1 and Cys1. Based on reporter gene assays performed in mouse renal collecting duct cells (mIMCD-3), TFAP2B activated the Pkhd1 and Cys1 promoters and electromobility shift assay (EMSA) confirmed TFAP2B binding to the in silico identified sites. These results suggest that Tfap2b participates in a renal epithelial cell gene regulatory network that includes Pkhd1 and Cys1. Disruption of this network impairs renal tubular differentiation, causing ductal dilatation that is the hallmark of recessive PKD.
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Affiliation(s)
- Maoqing Wu
- Center for Translational Research, Children's National Hospital, Washington, DC, United States
| | - Naoe Harafuji
- Center for Translational Research, Children's National Hospital, Washington, DC, United States
| | - Amber K O'Connor
- O'Neal Comprehensive Cancer Center, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Ljubica Caldovic
- Center for Genetic Medicine Research, Children's National Hospital, Washington, DC, United States.,Department of Genomics and Precision Medicine, School of Medical and Health Sciences, The George Washington University, Washington, DC, United States
| | - Lisa M Guay-Woodford
- Center for Translational Research, Children's National Hospital, Washington, DC, United States.,Center for Genetic Medicine Research, Children's National Hospital, Washington, DC, United States
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13
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Vasileva VY, Sultanova RF, Sudarikova AV, Ilatovskaya DV. Insights Into the Molecular Mechanisms of Polycystic Kidney Diseases. Front Physiol 2021; 12:693130. [PMID: 34566674 PMCID: PMC8456103 DOI: 10.3389/fphys.2021.693130] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2021] [Accepted: 08/10/2021] [Indexed: 12/18/2022] Open
Abstract
Autosomal dominant (AD) and autosomal recessive (AR) polycystic kidney diseases (PKD) are severe multisystem genetic disorders characterized with formation and uncontrolled growth of fluid-filled cysts in the kidney, the spread of which eventually leads to the loss of renal function. Currently, there are no treatments for ARPKD, and tolvaptan is the only FDA-approved drug that alleviates the symptoms of ADPKD. However, tolvaptan has only a modest effect on disease progression, and its long-term use is associated with many side effects. Therefore, there is still a pressing need to better understand the fundamental mechanisms behind PKD development. This review highlights current knowledge about the fundamental aspects of PKD development (with a focus on ADPKD) including the PC1/PC2 pathways and cilia-associated mechanisms, major molecular cascades related to metabolism, mitochondrial bioenergetics, and systemic responses (hormonal status, levels of growth factors, immune system, and microbiome) that affect its progression. In addition, we discuss new information regarding non-pharmacological therapies, such as dietary restrictions, which can potentially alleviate PKD.
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Affiliation(s)
| | - Regina F Sultanova
- Saint-Petersburg State Chemical Pharmaceutical University, St. Petersburg, Russia.,Department of Physiology, Augusta University, Augusta, GA, United States
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14
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Yang C, Harafuji N, O'Connor AK, Kesterson RA, Watts JA, Majmundar AJ, Braun DA, Lek M, Laricchia KM, Fathy HM, Mane S, Shril S, Hildebrandt F, Guay-Woodford LM. Cystin genetic variants cause autosomal recessive polycystic kidney disease associated with altered Myc expression. Sci Rep 2021; 11:18274. [PMID: 34521872 PMCID: PMC8440558 DOI: 10.1038/s41598-021-97046-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Accepted: 07/22/2021] [Indexed: 11/08/2022] Open
Abstract
Mutation of the Cys1 gene underlies the renal cystic disease in the Cys1cpk/cpk (cpk) mouse that phenocopies human autosomal recessive polycystic kidney disease (ARPKD). Cystin, the protein product of Cys1, is expressed in the primary apical cilia of renal ductal epithelial cells. In previous studies, we showed that cystin regulates Myc expression via interaction with the tumor suppressor, necdin. Here, we demonstrate rescue of the cpk renal phenotype by kidney-specific expression of a cystin-GFP fusion protein encoded by a transgene integrated into the Rosa26 locus. In addition, we show that expression of the cystin-GFP fusion protein in collecting duct cells down-regulates expression of Myc in cpk kidneys. Finally, we report the first human patient with an ARPKD phenotype due to homozygosity for a deleterious splicing variant in CYS1. These findings suggest that mutations in Cys1/CYS1 cause an ARPKD phenotype in mouse and human, respectively, and that the renal cystic phenotype in the mouse is driven by overexpression of the Myc proto-oncogene.
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Affiliation(s)
- Chaozhe Yang
- Center for Translational Research, Children's National Research Institute, 111 Michigan Ave NW, Washington, DC, 20010, USA
| | - Naoe Harafuji
- Center for Translational Research, Children's National Research Institute, 111 Michigan Ave NW, Washington, DC, 20010, USA
| | - Amber K O'Connor
- Center for Translational Research, Children's National Research Institute, 111 Michigan Ave NW, Washington, DC, 20010, USA
| | - Robert A Kesterson
- Department of Genetics, University of Alabama at Birmingham, Birmingham, AL, 35294, USA
| | - Jacob A Watts
- Center for Translational Research, Children's National Research Institute, 111 Michigan Ave NW, Washington, DC, 20010, USA
- Department of Genetics, University of Alabama at Birmingham, Birmingham, AL, 35294, USA
| | - Amar J Majmundar
- Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, MA, 02115, USA
| | - Daniela A Braun
- Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, MA, 02115, USA
| | - Monkol Lek
- Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Kristen M Laricchia
- Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Hanan M Fathy
- Alexandria Faculty of Medicine, University of Alexandria, Alexandria, Egypt
| | - Shrikant Mane
- Department of Genetics, Yale University School of Medicine, New Haven, CT, USA
- Yale Center for Mendelian Genomics, Yale University School of Medicine, New Haven, CT, USA
| | - Shirlee Shril
- Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, MA, 02115, USA
| | - Friedhelm Hildebrandt
- Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, MA, 02115, USA
| | - Lisa M Guay-Woodford
- Center for Translational Research, Children's National Research Institute, 111 Michigan Ave NW, Washington, DC, 20010, USA.
- Department of Genetics, University of Alabama at Birmingham, Birmingham, AL, 35294, USA.
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15
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The cellular pathways and potential therapeutics of Polycystic Kidney Disease. Biochem Soc Trans 2021; 49:1171-1188. [PMID: 34156429 DOI: 10.1042/bst20200757] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Revised: 05/28/2021] [Accepted: 06/03/2021] [Indexed: 02/07/2023]
Abstract
Polycystic Kidney Disease (PKD) refers to a group of disorders, driven by the formation of cysts in renal tubular cells and is currently one of the leading causes of end-stage renal disease. The range of symptoms observed in PKD is due to mutations in cilia-localising genes, resulting in changes in cellular signalling. As such, compounds that are currently in preclinical and clinical trials target some of these signalling pathways that are dysregulated in PKD. In this review, we highlight these pathways including cAMP, EGF and AMPK signalling and drugs that target them and may show promise in lessening the disease burden of PKD patients. At present, tolvaptan is the only approved therapy for ADPKD, however, it carries several adverse side effects whilst comparatively, no pharmacological drug is approved for ARPKD treatment. Aside from this, drugs that have been the subject of multiple clinical trials such as metformin, which targets AMPK signalling and somatostatins, which target cAMP signalling have shown great promise in reducing cyst formation and cellular proliferation. This review also discusses other potential and novel targets that can be used for future interventions, such as β-catenin and TAZ, where research has shown that a reduction in the overexpression of these signalling components results in amelioration of disease phenotype. Thus, it becomes apparent that well-designed preclinical investigations and future clinical trials into these pathways and other potential signalling targets are crucial in bettering disease prognosis for PKD patients and could lead to personalised therapy approaches.
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16
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Cordido A, Vizoso-Gonzalez M, Garcia-Gonzalez MA. Molecular Pathophysiology of Autosomal Recessive Polycystic Kidney Disease. Int J Mol Sci 2021; 22:6523. [PMID: 34204582 PMCID: PMC8235086 DOI: 10.3390/ijms22126523] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 06/15/2021] [Accepted: 06/16/2021] [Indexed: 12/19/2022] Open
Abstract
Autosomal recessive polycystic kidney disease (ARPKD) is a rare disorder and one of the most severe forms of polycystic kidney disease, leading to end-stage renal disease (ESRD) in childhood. PKHD1 is the gene that is responsible for the vast majority of ARPKD. However, some cases have been related to a new gene that was recently identified (DZIP1L gene), as well as several ciliary genes that can mimic a ARPKD-like phenotypic spectrum. In addition, a number of molecular pathways involved in the ARPKD pathogenesis and progression were elucidated using cellular and animal models. However, the function of the ARPKD proteins and the molecular mechanism of the disease currently remain incompletely understood. Here, we review the clinics, treatment, genetics, and molecular basis of ARPKD, highlighting the most recent findings in the field.
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Affiliation(s)
- Adrian Cordido
- Grupo de Xenética e Bioloxía do Desenvolvemento das Enfermidades Renais, Laboratorio de Nefroloxía (No. 11), Instituto de Investigación Sanitaria de Santiago (IDIS), Complexo Hospitalario de Santiago de Compostela (CHUS), 15706 Santiago de Compostela, Spain; (A.C.); (M.V.-G.)
- Grupo de Medicina Xenómica, Complexo Hospitalario de Santiago de Compostela (CHUS), 15706 Santiago de Compostela, Spain
| | - Marta Vizoso-Gonzalez
- Grupo de Xenética e Bioloxía do Desenvolvemento das Enfermidades Renais, Laboratorio de Nefroloxía (No. 11), Instituto de Investigación Sanitaria de Santiago (IDIS), Complexo Hospitalario de Santiago de Compostela (CHUS), 15706 Santiago de Compostela, Spain; (A.C.); (M.V.-G.)
- Grupo de Medicina Xenómica, Complexo Hospitalario de Santiago de Compostela (CHUS), 15706 Santiago de Compostela, Spain
| | - Miguel A. Garcia-Gonzalez
- Grupo de Xenética e Bioloxía do Desenvolvemento das Enfermidades Renais, Laboratorio de Nefroloxía (No. 11), Instituto de Investigación Sanitaria de Santiago (IDIS), Complexo Hospitalario de Santiago de Compostela (CHUS), 15706 Santiago de Compostela, Spain; (A.C.); (M.V.-G.)
- Grupo de Medicina Xenómica, Complexo Hospitalario de Santiago de Compostela (CHUS), 15706 Santiago de Compostela, Spain
- Fundación Publica Galega de Medicina Xenómica-SERGAS, Complexo Hospitalario de Santiago de Compostela (CHUS), 15706 Santiago de Compostela, Spain
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17
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Fine-scale visualizing the hierarchical structure of mouse biliary tree with fluorescence microscopy method. Biosci Rep 2021; 40:223572. [PMID: 32364232 PMCID: PMC7218221 DOI: 10.1042/bsr20193757] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2019] [Revised: 04/15/2020] [Accepted: 05/01/2020] [Indexed: 02/05/2023] Open
Abstract
The liver is a vital organ and the hepatic lobule serves as the most basic structural and functional unit which is mainly assembled with parenchymal cells including hepatocytes and biliary epithelial cells. The continuous tubular arrangement of biliary cells which constitutes the biliary tracts is critical for liver function, however, the biliary tracts are often disrupted in many liver diseases such as cirrhosis and some congenital disorders. Visualization of the biliary tracts in fine-scale and three-dimension will help to understanding the structure basis of these liver diseases. In the present study, we established several biliary tract injury mouse models by diet feeding, surgery or genetic modification. The cytoplasm and nuclei of the parenchymal cells were marked by active uptake of fluorescent dyes Rhodamine B (red) and Hoechst (blue), respectively. After the removal of liver en bloc, the biliary tracts were retrogradely perfused with green fluorescent dye, fluorescein isothiocyanate (FITC). The liver was then observed under confocal microscopy. The fine-scale and three-dimensional (3D) structure of the whole biliary tree, particularly the network of the end-terminal bile canaliculi and neighboring hepatocytes were clearly visualized. The biliary tracts displayed clear distinct characteristics in normal liver and diseased liver models. Taken together, we have developed a simple and repeatable imaging method to visualize the fine-scale and hierarchical architecture of the biliary tracts spreading in the mouse liver.
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18
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De Miguel C, Pelegrín P, Baroja-Mazo A, Cuevas S. Emerging Role of the Inflammasome and Pyroptosis in Hypertension. Int J Mol Sci 2021; 22:ijms22031064. [PMID: 33494430 PMCID: PMC7865380 DOI: 10.3390/ijms22031064] [Citation(s) in RCA: 61] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Revised: 01/14/2021] [Accepted: 01/18/2021] [Indexed: 02/06/2023] Open
Abstract
Inflammasomes are components of the innate immune response that have recently emerged as crucial controllers of tissue homeostasis. In particular, the nucleotide-binding domain, leucine-rich-containing (NLR) family pyrin domain containing 3 (NLRP3) inflammasome is a complex platform involved in the activation of caspase-1 and the maturation of interleukin (IL)-1β and IL-18, which are mainly released via pyroptosis. Pyroptosis is a caspase-1-dependent type of cell death that is mediated by the cleavage of gasdermin D and the subsequent formation of structurally stable pores in the cell membrane. Through these pores formed by gasdermin proteins cytosolic contents are released into the extracellular space and act as damage-associated molecular patterns, which are pro-inflammatory signals. Inflammation is a main contributor to the development of hypertension and it also is known to stimulate fibrosis and end-organ damage. Patients with essential hypertension and animal models of hypertension exhibit elevated levels of circulating IL-1β. Downregulation of the expression of key components of the NLRP3 inflammasome delays the development of hypertension and pharmacological inhibition of this inflammasome leads to reduced blood pressure in animal models and humans. Although the relationship between pyroptosis and hypertension is not well established yet, pyroptosis has been associated with renal and cardiovascular diseases, instances where high blood pressure is a critical risk factor. In this review, we summarize the recent literature addressing the role of pyroptosis and the inflammasome in the development of hypertension and discuss the potential use of approaches targeting this pathway as future anti-hypertensive strategies.
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Affiliation(s)
- Carmen De Miguel
- Section of Cardio-Renal Physiology and Medicine, Division of Nephrology, Department of Medicine, University of Alabama at Birmingham, Birmingham, AL 35233, USA
- Correspondence: (C.D.M.); (S.C.); Tel.: +34-868-885031 (S.C.)
| | - Pablo Pelegrín
- Molecular Inflammation Group, Biomedical Research Institute of Murcia (IMIB-Arrixaca), 30120 Murcia, Spain; (P.P.); (A.B.-M.)
| | - Alberto Baroja-Mazo
- Molecular Inflammation Group, Biomedical Research Institute of Murcia (IMIB-Arrixaca), 30120 Murcia, Spain; (P.P.); (A.B.-M.)
| | - Santiago Cuevas
- Molecular Inflammation Group, Biomedical Research Institute of Murcia (IMIB-Arrixaca), 30120 Murcia, Spain; (P.P.); (A.B.-M.)
- Correspondence: (C.D.M.); (S.C.); Tel.: +34-868-885031 (S.C.)
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19
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Possible PKHD1 Hot-spot Mutations Related to Early Kidney Function Failure or Hepatofibrosis in Chinese Children with ARPKD: A Retrospective Single Center Cohort Study and Literature Review. Curr Med Sci 2020; 40:835-844. [PMID: 33123899 DOI: 10.1007/s11596-020-2268-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Accepted: 08/23/2020] [Indexed: 10/23/2022]
Abstract
PKHD1 mutations are generally considered to cause autosomal recessive polycystic kidney disease (ARPKD). ARPKD is a rare disorder and one of the most severe conditions leading to end-stage renal disease in childhood. With the biallelic deletion mutation, patients have difficulty in surviving the perinatal period, resulting in perinatal or neonatal death. This study retrospectively analyzed patient characteristics, imaging characteristics, laboratory examinations and family surveys from 7 Chinese children with different PKHD1 gene mutations diagnosed by high-throughput sequencing from January 2014 to February 2018. Of the 7 children, there were 3 males and 4 females. Eight missense mutations, two frameshift mutations, two deletion mutations, and two intronic slicing mutations were identified. Six of the mutations have not previously been identified. In the literature search, we identified a total of 29 Chinese children with PKHD1 mutations. The missense mutation c.2507T>C in exon 24 was found in one patient in our study, and five patients with liver fibrosis but normal renal function were reported in the literature. The missense mutation c.5935G>A in exon 37 was found in two patients in our study and three cases in the literature. Four patients had renal failure at an age as young as 1 year of those five patients with the missense mutation c.5935G>A in exon 37. It was concluded that: (1) Kidney length more than 2-3 SDs above the mean and early-onset hypertension might be associated with PKHD1-associated ARPKD; (2) The more enlarged the kidney size is, the lower the renal function is likely to be; (3) c.5935G>A may be a hot spot that leads to early renal failure in Chinese children with PKHD1 mutations; (4) c.2507T>C may be a hot-spot mutation associated with hepatic lesions in Chinese children with PKHD1.
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20
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Dafinger C, Mandel AM, Braun A, Göbel H, Burgmaier K, Massella L, Mastrangelo A, Dötsch J, Benzing T, Weimbs T, Schermer B, Liebau MC. The carboxy-terminus of the human ARPKD protein fibrocystin can control STAT3 signalling by regulating SRC-activation. J Cell Mol Med 2020; 24:14633-14638. [PMID: 33112055 PMCID: PMC7754027 DOI: 10.1111/jcmm.16014] [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: 06/15/2020] [Revised: 10/02/2020] [Accepted: 10/03/2020] [Indexed: 12/04/2022] Open
Abstract
Autosomal recessive polycystic kidney disease (ARPKD) is mainly caused by variants in the PKHD1 gene, encoding fibrocystin (FC), a large transmembrane protein of incompletely understood cellular function. Here, we show that a C‐terminal fragment of human FC can suppress a signalling module of the kinase SRC and signal transducer and activator of transcription 3 (STAT3). Consistently, we identified truncating genetic variants specifically affecting the cytoplasmic tail in ARPKD patients, found SRC and the cytoplasmic tail of fibrocystin in a joint dynamic protein complex and observed increased activation of both SRC and STAT3 in cyst‐lining renal epithelial cells of ARPKD patients.
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Affiliation(s)
- Claudia Dafinger
- Department of Pediatrics, University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany.,Department II of Internal Medicine, University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany.,Center for Molecular Medicine, University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany
| | - Amrei M Mandel
- Department of Pediatrics, University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany.,Department II of Internal Medicine, University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany
| | - Alina Braun
- Department of Pediatrics, University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany.,Department II of Internal Medicine, University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany
| | - Heike Göbel
- Institute of Pathology, Faculty of Medicine, University Hospital Cologne and University of Cologne, Cologne, Germany
| | - Kathrin Burgmaier
- Department of Pediatrics, University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany
| | - Laura Massella
- Nephrology and Dialysis Unit, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy
| | - Antonio Mastrangelo
- Pediatric Nephrology, Dialysis and Transplant Unit, Fondazione IRCCS Cà Granda, Ospedale Maggiore Policlinico, Milan, Italy
| | - Jörg Dötsch
- Department of Pediatrics, University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany
| | - Thomas Benzing
- Department II of Internal Medicine, University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany.,Center for Molecular Medicine, University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany.,CECAD, University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany.,Systems Biology of Ageing Cologne, University of Cologne, Cologne, Germany
| | - Thomas Weimbs
- Molecular, Cellular, and Developmental Biology, and Neuroscience Research Institute, University of California, Santa Barbara, CA, USA
| | - Bernhard Schermer
- Department II of Internal Medicine, University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany.,Center for Molecular Medicine, University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany.,CECAD, University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany.,Systems Biology of Ageing Cologne, University of Cologne, Cologne, Germany
| | - Max C Liebau
- Department of Pediatrics, University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany.,Department II of Internal Medicine, University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany.,Center for Molecular Medicine, University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany
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21
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Molinari E, Srivastava S, Dewhurst RM, Sayer JA. Use of patient derived urine renal epithelial cells to confirm pathogenicity of PKHD1 alleles. BMC Nephrol 2020; 21:435. [PMID: 33059616 PMCID: PMC7559414 DOI: 10.1186/s12882-020-02094-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Accepted: 10/08/2020] [Indexed: 02/07/2023] Open
Abstract
Background PKHD1 is the main genetic cause of autosomal recessive polycystic kidney disease (ARPKD), a hereditary hepato-renal fibrocystic disorder which is the most important cause of end-stage renal disease during early childhood. ARPKD can also present in adulthood with milder phenotypes. In this study, we describe a 24-year-old woman with atypical polycystic kidney, no family history of renal disease and no obvious extra-renal manifestations who was referred for genetic investigation. Methods We used a combination of next generation sequencing, Sanger sequencing and RNA and microscopy studies performed on urine-derived renal epithelial cells (URECs) to provide a genetic diagnosis of ARPKD. Results A next generation sequencing panel of cystic ciliopathy genes allowed the identification of two heterozygous sequence changes in PKHD1 (c.6900C > T; p.(Asn2300=) and c.7964A > C; p.(His2655Pro)). The pathogenicity of the synonymous PKHD1 variant is not clear and requires RNA studies, which cannot be carried out efficiently on RNA extracted from proband blood, due to the low expression levels of PKHD1 in lymphocytes. Using URECs as a source of kidney-specific RNA, we show that PKHD1 is alternatively spliced around exon 43, both in control and proband URECs. The variant p.(Asn2300=) shifts the expression ratio in favour of a shorter, out-of-frame transcript. To further study the phenotypic consequence of these variants, we investigated the ciliary phenotype of patient URECs, which were abnormally elongated and presented multiple blebs along the axoneme. Conclusions We confirm the power of URECs as a tool for functional studies on candidate variants in inherited renal disease, especially when the expression of the gene of interest is restricted to the kidney and we describe, for the first time, ciliary abnormalities in ARPKD patient cells.
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Affiliation(s)
- Elisa Molinari
- Translational and Clinical Research Institute, Faculty of Medical Sciences, Newcastle University, International Centre for Life, Central Parkway, Newcastle upon Tyne, NE1 3BZ, UK
| | - Shalabh Srivastava
- Translational and Clinical Research Institute, Faculty of Medical Sciences, Newcastle University, International Centre for Life, Central Parkway, Newcastle upon Tyne, NE1 3BZ, UK
| | - Rebecca M Dewhurst
- Translational and Clinical Research Institute, Faculty of Medical Sciences, Newcastle University, International Centre for Life, Central Parkway, Newcastle upon Tyne, NE1 3BZ, UK
| | - John A Sayer
- Translational and Clinical Research Institute, Faculty of Medical Sciences, Newcastle University, International Centre for Life, Central Parkway, Newcastle upon Tyne, NE1 3BZ, UK. .,Renal Services, The Newcastle Hospitals NHS Foundation Trust, Newcastle upon Tyne, NE7 7DN, UK. .,NIHR Newcastle Biomedical Research Centre, Newcastle upon Tyne, UK.
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McConnachie DJ, Stow JL, Mallett AJ. Ciliopathies and the Kidney: A Review. Am J Kidney Dis 2020; 77:410-419. [PMID: 33039432 DOI: 10.1053/j.ajkd.2020.08.012] [Citation(s) in RCA: 111] [Impact Index Per Article: 27.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Accepted: 08/11/2020] [Indexed: 12/19/2022]
Abstract
Primary cilia are specialized sensory organelles that protrude from the apical surface of most cell types. During the past 2 decades, they have been found to play important roles in tissue development and signal transduction, with mutations in ciliary-associated proteins resulting in a group of diseases collectively known as ciliopathies. Many of these mutations manifest as renal ciliopathies, characterized by kidney dysfunction resulting from aberrant cilia or ciliary functions. This group of overlapping and genetically heterogeneous diseases includes polycystic kidney disease, nephronophthisis, and Bardet-Biedl syndrome as the main focus of this review. Renal ciliopathies are characterized by the presence of kidney cysts that develop due to uncontrolled epithelial cell proliferation, growth, and polarity, downstream of dysregulated ciliary-dependent signaling. Due to cystic-associated kidney injury and systemic inflammation, cases result in kidney failure requiring dialysis and transplantation. Of the handful of pharmacologic treatments available, none are curative. It is important to determine the molecular mechanisms that underlie the involvement of the primary cilium in cyst initiation, expansion, and progression for the development of novel and efficacious treatments. This review updates research progress in defining key genes and molecules central to ciliogenesis and renal ciliopathies.
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Affiliation(s)
- Dominique J McConnachie
- Institute for Molecular Bioscience (IMB) and IMB Centre for Inflammation Disease and Research, The University of Queensland, Brisbane, QLD, Australia
| | - Jennifer L Stow
- Kidney Health Service, Royal Brisbane and Women's Hospital, Brisbane, QLD, Australia
| | - Andrew J Mallett
- Institute for Molecular Bioscience (IMB) and IMB Centre for Inflammation Disease and Research, The University of Queensland, Brisbane, QLD, Australia; Kidney Health Service, Royal Brisbane and Women's Hospital, Brisbane, QLD, Australia; Faculty of Medicine, The University of Queensland, Brisbane, QLD, Australia; KidGen Collaborative, Australian Genomics Health Alliance, Melbourne, VIC, Australia.
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23
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Haumann S, Müller RU, Liebau MC. Metabolic Changes in Polycystic Kidney Disease as a Potential Target for Systemic Treatment. Int J Mol Sci 2020; 21:ijms21176093. [PMID: 32847032 PMCID: PMC7503958 DOI: 10.3390/ijms21176093] [Citation(s) in RCA: 9] [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: 06/30/2020] [Revised: 08/17/2020] [Accepted: 08/19/2020] [Indexed: 12/16/2022] Open
Abstract
Autosomal recessive and autosomal dominant polycystic kidney disease (ARPKD, ADPKD) are systemic disorders with pronounced hepatorenal phenotypes. While the main underlying genetic causes of both ARPKD and ADPKD have been well-known for years, the exact molecular mechanisms resulting in the observed clinical phenotypes in the different organs, remain incompletely understood. Recent research has identified cellular metabolic changes in PKD. These findings are of major relevance as there may be an immediate translation into clinical trials and potentially clinical practice. Here, we review important results in the field regarding metabolic changes in PKD and their modulation as a potential target of systemic treatment.
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Affiliation(s)
- Sophie Haumann
- Department of Pediatrics, University of Cologne, Faculty of Medicine and University Hospital Cologne, 50937 Cologne, Germany;
| | - Roman-Ulrich Müller
- Department II of Internal Medicine, University of Cologne, Faculty of Medicine and University Hospital Cologne, 50937 Cologne, Germany;
- CECAD, University of Cologne, Faculty of Medicine and University Hospital Cologne, 50931 Cologne, Germany
- Systems Biology of Ageing Cologne, University of Cologne, 50931 Cologne, Germany
| | - Max C. Liebau
- Department of Pediatrics, University of Cologne, Faculty of Medicine and University Hospital Cologne, 50937 Cologne, Germany;
- Center for Molecular Medicine, University of Cologne, Faculty of Medicine and University Hospital Cologne, 50931 Cologne, Germany
- Correspondence: ; Tel.: +49-221-478-4359
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24
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Gallagher AR, Somlo S. Loss of Cilia Does Not Slow Liver Disease Progression in Mouse Models of Autosomal Recessive Polycystic Kidney Disease. ACTA ACUST UNITED AC 2020; 1:962-968. [PMID: 33829210 DOI: 10.34067/kid.0001022019] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Anna Rachel Gallagher
- Department of Internal Medicine (Nephrology), Yale School of Medicine, New Haven, Connecticut
| | - Stefan Somlo
- Department of Internal Medicine (Nephrology), Yale School of Medicine, New Haven, Connecticut.,Department of Genetics, Yale School of Medicine, New Haven, Connecticut
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25
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Cilia and polycystic kidney disease. Semin Cell Dev Biol 2020; 110:139-148. [PMID: 32475690 DOI: 10.1016/j.semcdb.2020.05.003] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2020] [Revised: 05/03/2020] [Accepted: 05/03/2020] [Indexed: 11/20/2022]
Abstract
Polycystic kidney disease (PKD), comprising autosomal dominant polycystic kidney disease (ADPKD) and autosomal recessive polycystic kidney disease (ARPKD), is characterized by incessant cyst formation in the kidney and liver. ADPKD and ARPKD represent the leading genetic causes of renal disease in adults and children, respectively. ADPKD is caused by mutations in PKD1 encoding polycystin1 (PC1) and PKD2 encoding polycystin 2 (PC2). PC1/2 are multi-pass transmembrane proteins that form a complex localized in the primary cilium. Predominant ARPKD cases are caused by mutations in polycystic kidney and hepatic disease 1 (PKHD1) gene that encodes the Fibrocystin/Polyductin (FPC) protein, whereas a small subset of cases are caused by mutations in DAZ interacting zinc finger protein 1 like (DZIP1L) gene. FPC is a type I transmembrane protein, localizing to the cilium and basal body, in addition to other compartments, and DZIP1L encodes a transition zone/basal body protein. Apparently, PC1/2 and FPC are signaling molecules, while the mechanism that cilia employ to govern renal tubule morphology and prevent cyst formation is unclear. Nonetheless, recent genetic and biochemical studies offer a glimpse of putative physiological malfunctions and the pathomechanisms underlying both disease entities. In this review, I summarize the results of genetic studies that deduced the function of PC1/2 on cilia and of cilia themselves in cyst formation in ADPKD, and I discuss studies regarding regulation of polycystin biogenesis and cilia trafficking. I also summarize the synergistic genetic interactions between Pkd1 and Pkhd1, and the unique tissue patterning event controlled by FPC, but not PC1. Interestingly, while DZIP1L mutations generate compromised PC1/2 cilia expression, FPC deficiency does not affect PC1/2 biogenesis and ciliary localization, indicating that divergent mechanisms could lead to cyst formation in ARPKD. I conclude by outlining promising areas for future PKD research and highlight rationales for potential therapeutic interventions for PKD treatment.
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Abstract
Mutations in the polycystins PC1 or PC2 cause autosomal dominant polycystic kidney disease (ADPKD), which is characterized by the formation of fluid-filled renal cysts that disrupt renal architecture and function, ultimately leading to kidney failure in the majority of patients. Although the genetic basis of ADPKD is now well established, the physiological function of polycystins remains obscure and a matter of intense debate. The structural determination of both the homomeric PC2 and heteromeric PC1-PC2 complexes, as well as the electrophysiological characterization of PC2 in the primary cilium of renal epithelial cells, provided new valuable insights into the mechanisms of ADPKD pathogenesis. Current findings indicate that PC2 can function independently of PC1 in the primary cilium of renal collecting duct epithelial cells to form a channel that is mainly permeant to monovalent cations and is activated by both membrane depolarization and an increase in intraciliary calcium. In addition, PC2 functions as a calcium-activated calcium release channel at the endoplasmic reticulum membrane. Structural studies indicate that the heteromeric PC1-PC2 complex comprises one PC1 and three PC2 channel subunits. Surprisingly, several positively charged residues from PC1 occlude the ionic pore of the PC1-PC2 complex, suggesting that pathogenic polycystin mutations might cause ADPKD independently of an effect on channel permeation. Emerging reports of novel structural and functional findings on polycystins will continue to elucidate the molecular basis of ADPKD.
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27
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Lea WA, McGreal K, Sharma M, Parnell SC, Zelenchuk L, Charlesworth MC, Madden BJ, Johnson KL, McCormick DJ, Hogan MC, Ward CJ. Analysis of the polycystin complex (PCC) in human urinary exosome-like vesicles (ELVs). Sci Rep 2020; 10:1500. [PMID: 32001768 PMCID: PMC6992733 DOI: 10.1038/s41598-020-58087-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2019] [Accepted: 01/05/2020] [Indexed: 12/21/2022] Open
Abstract
The polycystin-1 (PC1), polycystin-2 (PC2) and fibrocystin proteins, the respective products of the PKD1, PKD2 and PKHD1 genes, are abundant in urinary exosome-like vesicles (ELVs) where they form the polycystin complex (PCC). ELVs are 100 nm diameter membrane vesicles shed into the urine by the cells lining the nephron. Using MS/MS analysis of ELVs from individuals with PKD1 mutations and controls, we show that in addition to the well-described GPS/GAIN cleavage event in PC1 at 3048 aa and the proprotein convertase cleavage (PPC) event in fibrocystin at 3616 aa, there are multiple other cleavage events in these proteins. The C-terminal 11 transmembrane portion of PC1 undergoes three cleavage events in vivo. The absence of peptides from the C-terminal cytoplasmic tail of fibrocystin implies a cleavage event close to its single TM domain prior to loading onto the ELVs. There is also evidence that the C-terminal tail of PC2 is also cleaved in ELVs. Native gel analysis of the PCC shows that the entire complex is > 2 MDa in size and that N-terminal GPS/GAIN cleaved PC1 and PPC cleaved fibrocystin ectodomains can be released under non-reducing conditions and resolve at 300 kDa. This paper shows that the three major human cystogene proteins are detectable in human urinary ELVs and that all three undergo post-translational proteolytic processing. Human urinary ELVs may be a useful source of material in the search for proteins that interact with the PCC.
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Affiliation(s)
- Wendy A Lea
- The Jared Grantham Kidney Institute, University of Kansas Medical Center, Kansas City, KS 66160, USA
| | - Kerri McGreal
- The Jared Grantham Kidney Institute, University of Kansas Medical Center, Kansas City, KS 66160, USA
| | - Madhulika Sharma
- The Jared Grantham Kidney Institute, University of Kansas Medical Center, Kansas City, KS 66160, USA
| | - Stephen C Parnell
- The Jared Grantham Kidney Institute, University of Kansas Medical Center, Kansas City, KS 66160, USA
- Department of Biochemistry and Molecular Biology, University of Kansas Medical Center, Kansas City, KS 66160, USA
| | - Lesya Zelenchuk
- The Jared Grantham Kidney Institute, University of Kansas Medical Center, Kansas City, KS 66160, USA
| | - M Cristine Charlesworth
- Mayo Proteomic Core, Medical Sciences Building, Ms 3-121, Mayo Clinic, 200 First Street, SW Rochester, MN, 55905, USA
| | - Benjamin J Madden
- Mayo Proteomic Core, Medical Sciences Building, Ms 3-121, Mayo Clinic, 200 First Street, SW Rochester, MN, 55905, USA
| | - Kenneth L Johnson
- Mayo Proteomic Core, Medical Sciences Building, Ms 3-121, Mayo Clinic, 200 First Street, SW Rochester, MN, 55905, USA
| | - Daniel J McCormick
- Mayo Proteomic Core, Medical Sciences Building, Ms 3-121, Mayo Clinic, 200 First Street, SW Rochester, MN, 55905, USA
| | - Marie C Hogan
- Division of Nephrology, Department of Internal Medicine, Mayo Clinic, Rochester, USA
| | - Christopher J Ward
- The Jared Grantham Kidney Institute, University of Kansas Medical Center, Kansas City, KS 66160, USA.
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28
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Pazour GJ, Quarmby L, Smith AO, Desai PB, Schmidts M. Cilia in cystic kidney and other diseases. Cell Signal 2019; 69:109519. [PMID: 31881326 DOI: 10.1016/j.cellsig.2019.109519] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2019] [Revised: 12/21/2019] [Accepted: 12/21/2019] [Indexed: 12/23/2022]
Abstract
Epithelial cells lining the ducts and tubules of the kidney nephron and collecting duct have a single non-motile cilium projecting from their surface into the lumen of the tubule. These organelles were long considered vestigial remnants left as a result of evolution from a ciliated ancestor, but we now recognize them as critical sensory antennae. In the kidney, the polycystins and fibrocystin, products of the major human polycystic kidney disease genes, localize to this organelle. The polycystins and fibrocystin, through an unknown mechanism, monitor the diameter of the kidney tubules and regulate the proliferation and differentiation of the cells lining the tubule. When the polycystins, fibrocystin or cilia themselves are defective, the cell perceives this as a pro-proliferative signal, which leads to tubule dilation and cystic disease. In addition to critical roles in preventing cyst formation in the kidney, cilia are also important in cystic and fibrotic diseases of the liver and pancreas, and ciliary defects lead to a variety of developmental abnormalities that cause structural birth defects in most organs.
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Affiliation(s)
- Gregory J Pazour
- Program in Molecular Medicine, University of Massachusetts Medical School, Biotech II, Suite 213, 373 Plantation Street, Worcester, MA 01605, United States of America.
| | - Lynne Quarmby
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada.
| | - Abigail O Smith
- Program in Molecular Medicine, University of Massachusetts Medical School, Biotech II, Suite 213, 373 Plantation Street, Worcester, MA 01605, United States of America
| | - Paurav B Desai
- Program in Molecular Medicine, University of Massachusetts Medical School, Biotech II, Suite 213, 373 Plantation Street, Worcester, MA 01605, United States of America
| | - Miriam Schmidts
- Center for Pediatrics and Adolescent Medicine, University Hospital Freiburg, Freiburg University Faculty of Medicine, Mathildenstrasse 1, 79112 Freiburg, Germany.
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29
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Olson RJ, Hopp K, Wells H, Smith JM, Furtado J, Constans MM, Escobar DL, Geurts AM, Torres VE, Harris PC. Synergistic Genetic Interactions between Pkhd1 and Pkd1 Result in an ARPKD-Like Phenotype in Murine Models. J Am Soc Nephrol 2019; 30:2113-2127. [PMID: 31427367 PMCID: PMC6830782 DOI: 10.1681/asn.2019020150] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2019] [Accepted: 07/12/2019] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND Autosomal recessive polycystic kidney disease (ARPKD) and autosomal dominant polycystic kidney disease (ADPKD) are genetically distinct, with ADPKD usually caused by the genes PKD1 or PKD2 (encoding polycystin-1 and polycystin-2, respectively) and ARPKD caused by PKHD1 (encoding fibrocystin/polyductin [FPC]). Primary cilia have been considered central to PKD pathogenesis due to protein localization and common cystic phenotypes in syndromic ciliopathies, but their relevance is questioned in the simple PKDs. ARPKD's mild phenotype in murine models versus in humans has hampered investigating its pathogenesis. METHODS To study the interaction between Pkhd1 and Pkd1, including dosage effects on the phenotype, we generated digenic mouse and rat models and characterized and compared digenic, monogenic, and wild-type phenotypes. RESULTS The genetic interaction was synergistic in both species, with digenic animals exhibiting phenotypes of rapidly progressive PKD and early lethality resembling classic ARPKD. Genetic interaction between Pkhd1 and Pkd1 depended on dosage in the digenic murine models, with no significant enhancement of the monogenic phenotype until a threshold of reduced expression at the second locus was breached. Pkhd1 loss did not alter expression, maturation, or localization of the ADPKD polycystin proteins, with no interaction detected between the ARPKD FPC protein and polycystins. RNA-seq analysis in the digenic and monogenic mouse models highlighted the ciliary compartment as a common dysregulated target, with enhanced ciliary expression and length changes in the digenic models. CONCLUSIONS These data indicate that FPC and the polycystins work independently, with separate disease-causing thresholds; however, a combined protein threshold triggers the synergistic, cystogenic response because of enhanced dysregulation of primary cilia. These insights into pathogenesis highlight possible common therapeutic targets.
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Affiliation(s)
- Rory J Olson
- Department of Biochemistry and Molecular Biology, Mayo Graduate School of Biomedical Sciences, Rochester, Minnesota
| | - Katharina Hopp
- Division of Renal Diseases and Hypertension, University of Colorado, Denver, Colorado
| | - Harrison Wells
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, Minnesota
| | - Jessica M Smith
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, Minnesota
| | - Jessica Furtado
- Department of Biochemistry and Molecular Biology, Mayo Graduate School of Biomedical Sciences, Rochester, Minnesota
- Biological and Biomedical Sciences Program, Yale University School of Medicine, New Haven, Connecticut; and
| | - Megan M Constans
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, Minnesota
| | - Diana L Escobar
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, Minnesota
| | - Aron M Geurts
- Gene Editing Rat Resource Center, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - Vicente E Torres
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, Minnesota
| | - Peter C Harris
- Department of Biochemistry and Molecular Biology, Mayo Graduate School of Biomedical Sciences, Rochester, Minnesota;
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, Minnesota
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van Tol W, Ashikov A, Korsch E, Abu Bakar N, Willemsen MA, Thiel C, Lefeber DJ. A mutation in mannose-phosphate-dolichol utilization defect 1 reveals clinical symptoms of congenital disorders of glycosylation type I and dystroglycanopathy. JIMD Rep 2019; 50:31-39. [PMID: 31741824 PMCID: PMC6850978 DOI: 10.1002/jmd2.12060] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Revised: 05/25/2019] [Accepted: 05/29/2019] [Indexed: 12/11/2022] Open
Abstract
Congenital disorders of glycosylation type I (CDG-I) are inborn errors of metabolism, generally characterized by multisystem clinical manifestations, including developmental delay, hepatopathy, hypotonia, and skin, skeletal, and neurological abnormalities. Among others, dolichol-phosphate-mannose (DPM) is the mannose donor for N-glycosylation as well as O-mannosylation. DOLK-CDG, DPM1-CDG, DPM2-CDG, and DPM3-CDG are defects in the DPM synthesis showing both CDG-I abnormalities and reduced O-mannosylation of alpha-dystroglycan (αDG), which leads to muscular dystrophy-dystroglycanopathy. Mannose-phosphate-dolichol utilization defect 1 (MPDU1) plays a role in the utilization of DPM. Here, we report two MPDU1-CDG patients without skin involvement, but with massive dilatation of the biliary duct system and dystroglycanopathy characteristics including hypotonia, elevated creatine kinase, dilated cardiomyopathy, buphthalmos, and congenital glaucoma. Biochemical analyses revealed elevated disialotransferrin in serum, and analyses in fibroblasts showed shortened lipid linked oligosaccharides and DPM, and reduced O-mannosylation of αDG. Thus, MPDU1-CDG can be added to the list of disorders with overlapping biochemical and clinical abnormalities of CDG-I and dystroglycanopathy. SYNOPSIS Mannose-phosphate-dolichol utilization defect 1 patients can have overlapping biochemical and clinical abnormalities of congenital disorders of glycosylation type I and dystroglycanopathy.
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Affiliation(s)
- Walinka van Tol
- Department of Neurology, Donders Institute for Brain, Cognition and BehaviorRadboud University Medical CenterNijmegenThe Netherlands
- Translational Metabolic Laboratory, Department of Laboratory Medicine, Radboud Institute for Molecular Life SciencesRadboud University Medical CenterNijmegenThe Netherlands
| | - Angel Ashikov
- Department of Neurology, Donders Institute for Brain, Cognition and BehaviorRadboud University Medical CenterNijmegenThe Netherlands
| | - Eckhard Korsch
- Children's Hospital of the City of CologneCologneGermany
| | - Nurulamin Abu Bakar
- Department of Neurology, Donders Institute for Brain, Cognition and BehaviorRadboud University Medical CenterNijmegenThe Netherlands
| | - Michèl A. Willemsen
- Department of Pediatric Neurology, Amalia Children's Hospital, Donders Institute for Brain, Cognition and BehaviorRadboud University Medical CenterNijmegenThe Netherlands
| | - Christian Thiel
- Center for Child and Adolescent Medicine, Kinderheilkunde IUniversity of HeidelbergHeidelbergGermany
| | - Dirk J. Lefeber
- Department of Neurology, Donders Institute for Brain, Cognition and BehaviorRadboud University Medical CenterNijmegenThe Netherlands
- Translational Metabolic Laboratory, Department of Laboratory Medicine, Radboud Institute for Molecular Life SciencesRadboud University Medical CenterNijmegenThe Netherlands
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Richards T, Modarage K, Dean C, McCarthy-Boxer A, Hilton H, Esapa C, Norman J, Wilson P, Goggolidou P. Atmin modulates Pkhd1 expression and may mediate Autosomal Recessive Polycystic Kidney Disease (ARPKD) through altered non-canonical Wnt/Planar Cell Polarity (PCP) signalling. Biochim Biophys Acta Mol Basis Dis 2019; 1865:378-390. [PMID: 30414501 PMCID: PMC6335440 DOI: 10.1016/j.bbadis.2018.11.003] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Revised: 10/10/2018] [Accepted: 11/05/2018] [Indexed: 12/25/2022]
Abstract
Autosomal Recessive Polycystic Kidney Disease (ARPKD) is a genetic disorder with an incidence of ~1:20,000 that manifests in a wide range of renal and liver disease severity in human patients and can lead to perinatal mortality. ARPKD is caused by mutations in PKHD1, which encodes the large membrane protein, Fibrocystin, required for normal branching morphogenesis of the ureteric bud during embryonic renal development. The variation in ARPKD phenotype suggests that in addition to PKHD1 mutations, other genes may play a role, acting as modifiers of disease severity. One such pathway involves non-canonical Wnt/Planar Cell Polarity (PCP) signalling that has been associated with other cystic kidney diseases, but has not been investigated in ARPKD. Analysis of the AtminGpg6 mouse showed kidney, liver and lung abnormalities, suggesting it as a novel mouse tool for the study of ARPKD. Further, modulation of Atmin affected Pkhd1 mRNA levels, altered non-canonical Wnt/PCP signalling and impacted cellular proliferation and adhesion, although Atmin does not bind directly to the C-terminus of Fibrocystin. Differences in ATMIN and VANGL2 expression were observed between normal human paediatric kidneys and age-matched ARPKD kidneys. Significant increases in ATMIN, WNT5A, VANGL2 and SCRIBBLE were seen in human ARPKD versus normal kidneys; no substantial differences were seen in DAAM2 or NPHP2. A striking increase in E-cadherin was also detected in ARPKD kidneys. This work indicates a novel role for non-canonical Wnt/PCP signalling in ARPKD and suggests ATMIN as a modulator of PKHD1.
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MESH Headings
- Adolescent
- Apoptosis
- Cadherins/metabolism
- Cell Adhesion
- Cell Line
- Cell Polarity
- Cell Proliferation
- Child
- Child, Preschool
- Cytoskeleton/metabolism
- Embryo, Mammalian/metabolism
- Humans
- Infant
- Infant, Newborn
- Kidney Tubules, Collecting
- Phenotype
- Polycystic Kidney, Autosomal Recessive/genetics
- Polycystic Kidney, Autosomal Recessive/pathology
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Receptors, Cell Surface/genetics
- Receptors, Cell Surface/metabolism
- Transcription Factors/metabolism
- Wnt Signaling Pathway
- beta Catenin/metabolism
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Affiliation(s)
- Taylor Richards
- School of Biomedical Science and Physiology, Faculty of Science and Engineering, University of Wolverhampton, Wulfruna Street, Wolverhampton WV1 1LY, UK
| | - Kavindiya Modarage
- School of Biomedical Science and Physiology, Faculty of Science and Engineering, University of Wolverhampton, Wulfruna Street, Wolverhampton WV1 1LY, UK
| | - Charlotte Dean
- National Heart and Lung Institute, Imperial College, South Kensington Campus, London SW7 2AZ, UK; MRC Harwell Institute, Mammalian Genetics Unit, Harwell Campus, Oxfordshire OX11 0RD, UK
| | - Aidan McCarthy-Boxer
- Centre for Nephrology, UCL Medical School, Royal Free Campus, Rowland Hill, London NW3 2PF, UK
| | - Helen Hilton
- MRC Harwell Institute, Mammalian Genetics Unit, Harwell Campus, Oxfordshire OX11 0RD, UK
| | - Chris Esapa
- MRC Harwell Institute, Mammalian Genetics Unit, Harwell Campus, Oxfordshire OX11 0RD, UK
| | - Jill Norman
- Centre for Nephrology, UCL Medical School, Royal Free Campus, Rowland Hill, London NW3 2PF, UK
| | - Patricia Wilson
- Centre for Nephrology, UCL Medical School, Royal Free Campus, Rowland Hill, London NW3 2PF, UK
| | - Paraskevi Goggolidou
- School of Biomedical Science and Physiology, Faculty of Science and Engineering, University of Wolverhampton, Wulfruna Street, Wolverhampton WV1 1LY, UK; MRC Harwell Institute, Mammalian Genetics Unit, Harwell Campus, Oxfordshire OX11 0RD, UK; Centre for Nephrology, UCL Medical School, Royal Free Campus, Rowland Hill, London NW3 2PF, UK.
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Szabó T, Orosz P, Balogh E, Jávorszky E, Máttyus I, Bereczki C, Maróti Z, Kalmár T, Szabó AJ, Reusz G, Várkonyi I, Marián E, Gombos É, Orosz O, Madar L, Balla G, Kappelmayer J, Tory K, Balogh I. Comprehensive genetic testing in children with a clinical diagnosis of ARPKD identifies phenocopies. Pediatr Nephrol 2018; 33:1713-1721. [PMID: 29956005 DOI: 10.1007/s00467-018-3992-5] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/09/2018] [Revised: 05/12/2018] [Accepted: 05/29/2018] [Indexed: 12/19/2022]
Abstract
BACKGROUND Autosomal recessive polycystic kidney disease (ARPKD) is genetically one of the least heterogeneous ciliopathies, resulting primarily from mutations of PKHD1. Nevertheless, 13-20% of patients diagnosed with ARPKD are found not to carry PKHD1 mutations by sequencing. Here, we assess whether PKHD1 copy number variations or second locus mutations explain these cases. METHODS Thirty-six unrelated patients with the clinical diagnosis of ARPKD were screened for PKHD1 point mutations and copy number variations. Patients without biallelic mutations were re-evaluated and screened for second locus mutations targeted by the phenotype, followed, if negative, by clinical exome sequencing. RESULTS Twenty-eight patients (78%) carried PKHD1 point mutations, three of whom on only one allele. Two of the three patients harbored in trans either a duplication of exons 33-35 or a large deletion involving exons 1-55. All eight patients without PKHD1 mutations (22%) harbored mutations in other genes (PKD1 (n = 2), HNF1B (n = 3), NPHP1, TMEM67, PKD1/TSC2). Perinatal respiratory failure, a kidney length > +4SD and early-onset hypertension increase the likelihood of PKHD1-associated ARPKD. A patient compound heterozygous for a second and a last exon truncating PKHD1 mutation (p.Gly4013Alafs*25) presented with a moderate phenotype, indicating that fibrocystin is partially functional in the absence of its C-terminal 62 amino acids. CONCLUSIONS We found all ARPKD cases without PKHD1 point mutations to be phenocopies, and none to be explained by biallelic PKHD1 copy number variations. Screening for copy number variations is recommended in patients with a heterozygous point mutation.
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Affiliation(s)
- Tamás Szabó
- Department of Pediatrics, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Petronella Orosz
- Department of Pediatrics, Faculty of Medicine, University of Debrecen, Debrecen, Hungary.,Ist Department of Pediatrics, Semmelweis University Budapest, Bókay J. u. 53., Budapest, 1083, Hungary
| | - Eszter Balogh
- Ist Department of Pediatrics, Semmelweis University Budapest, Bókay J. u. 53., Budapest, 1083, Hungary.,MTA-SE Lendulet Nephrogenetic Laboratory, Budapest, Hungary
| | - Eszter Jávorszky
- Ist Department of Pediatrics, Semmelweis University Budapest, Bókay J. u. 53., Budapest, 1083, Hungary.,MTA-SE Lendulet Nephrogenetic Laboratory, Budapest, Hungary
| | - István Máttyus
- Ist Department of Pediatrics, Semmelweis University Budapest, Bókay J. u. 53., Budapest, 1083, Hungary
| | - Csaba Bereczki
- Department of Pediatrics, University of Szeged, Szeged, Hungary
| | - Zoltán Maróti
- Department of Pediatrics, University of Szeged, Szeged, Hungary
| | - Tibor Kalmár
- Department of Pediatrics, University of Szeged, Szeged, Hungary
| | - Attila J Szabó
- Ist Department of Pediatrics, Semmelweis University Budapest, Bókay J. u. 53., Budapest, 1083, Hungary.,MTA-SE Pediatrics and Nephrology Research Group, Budapest, Hungary
| | - George Reusz
- Ist Department of Pediatrics, Semmelweis University Budapest, Bókay J. u. 53., Budapest, 1083, Hungary
| | - Ildikó Várkonyi
- Ist Department of Pediatrics, Semmelweis University Budapest, Bókay J. u. 53., Budapest, 1083, Hungary
| | - Erzsébet Marián
- Department of Pediatrics, Szabolcs-Szatmár-Bereg Jósa András County Hospital, Nyíregyháza, Hungary
| | - Éva Gombos
- Division of Clinical Genetics, Department of Laboratory Medicine, Faculty of Medicine, University of Debrecen, 4032 Debrecen, Nagyerdei krt. 98., Debrecen, Hungary
| | - Orsolya Orosz
- Division of Clinical Genetics, Department of Laboratory Medicine, Faculty of Medicine, University of Debrecen, 4032 Debrecen, Nagyerdei krt. 98., Debrecen, Hungary
| | - László Madar
- Division of Clinical Genetics, Department of Laboratory Medicine, Faculty of Medicine, University of Debrecen, 4032 Debrecen, Nagyerdei krt. 98., Debrecen, Hungary
| | - György Balla
- Department of Pediatrics, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - János Kappelmayer
- Division of Clinical Genetics, Department of Laboratory Medicine, Faculty of Medicine, University of Debrecen, 4032 Debrecen, Nagyerdei krt. 98., Debrecen, Hungary
| | - Kálmán Tory
- Ist Department of Pediatrics, Semmelweis University Budapest, Bókay J. u. 53., Budapest, 1083, Hungary. .,MTA-SE Lendulet Nephrogenetic Laboratory, Budapest, Hungary.
| | - István Balogh
- Division of Clinical Genetics, Department of Laboratory Medicine, Faculty of Medicine, University of Debrecen, 4032 Debrecen, Nagyerdei krt. 98., Debrecen, Hungary.
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Lea WA, Ward CJ. A new epitope-tagged Pkhd1 allele sheds light on fibrocystin signaling. Kidney Int 2018; 92:1041-1043. [PMID: 29055424 DOI: 10.1016/j.kint.2017.05.026] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2017] [Accepted: 05/24/2017] [Indexed: 10/18/2022]
Abstract
In this issue of Kidney International, Outeda et al. present a new epitope-tagged allele of murine Pkhd1 that allows the monitoring of functional fibrocystin in vivo from the extreme C-terminus of the molecule. This work also shows that the removal of two-thirds of the intracellular tail of fibrocystin does not result in cystogenesis in either the liver or kidney, with major implications for our understanding of Pkhd1 function and polycystic kidney disease in general.
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Affiliation(s)
- Wendy A Lea
- Department of Nephrology, The Jared Grantham Kidney Institute at the University of Kansas Medical Center, Kansas City, Kansas, USA
| | - Christopher J Ward
- Department of Nephrology, The Jared Grantham Kidney Institute at the University of Kansas Medical Center, Kansas City, Kansas, USA.
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Targeted deletion of the AAA-ATPase Ruvbl1 in mice disrupts ciliary integrity and causes renal disease and hydrocephalus. Exp Mol Med 2018; 50:1-17. [PMID: 29959317 PMCID: PMC6026120 DOI: 10.1038/s12276-018-0108-z] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2017] [Revised: 03/12/2018] [Accepted: 03/16/2018] [Indexed: 02/06/2023] Open
Abstract
Ciliopathies comprise a large number of hereditary human diseases and syndromes caused by mutations resulting in dysfunction of either primary or motile cilia. Both types of cilia share a similar architecture. While primary cilia are present on most cell types, expression of motile cilia is limited to specialized tissues utilizing ciliary motility. We characterized protein complexes of ciliopathy proteins and identified the conserved AAA-ATPase Ruvbl1 as a common novel component. Here, we demonstrate that Ruvbl1 is crucial for the development and maintenance of renal tubular epithelium in mice: both constitutive and inducible deletion in tubular epithelial cells result in renal failure with tubular dilatations and fewer ciliated cells. Moreover, inducible deletion of Ruvbl1 in cells carrying motile cilia results in hydrocephalus, suggesting functional relevance in both primary and motile cilia. Cilia of Ruvbl1-negative cells lack crucial proteins, consistent with the concept of Ruvbl1-dependent cytoplasmic pre-assembly of ciliary protein complexes. A protein involved in building and maintaining thin protrusions from cell surfaces called cilia is implicated in “ciliopathies”, diseases in which ciliary function is disrupted. These include polycystic kidney disease and disorders collectively known as ciliary dyskinesias. “Primary cilia” perform sensory functions, detecting external chemical and physical signals and initiating responses within cells. In addition, “motile cilia” beat rhythmically to move fluids surrounding cells. Researchers in Germany and the Netherlands, led by Bernhard Schermer and Max C. Liebau at the University of Cologne, studied a protein called Ruvbl1, known to interact with DNA and other proteins. The researchers found it is crucial for the functioning of both types of cilia. Deleting the gene for Ruvbl1 in mice caused kidney failure and a build-up of fluid in the brain known as hydrocephalus. The research could help understand and ultimately treat ciliopathies.
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