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OCRL Deficiency Impairs Endolysosomal Function in a Humanized Mouse Model for Lowe Syndrome and Dent Disease


Festa, Beatrice Paola; Berquez, Marine; Gassama, Alkaly; Amrein, Irmgard; Ismail, Hesham M; Samardzija, Marijana; Staiano, Leopoldo; Luciani, Alessandro; Grimm, Christian; Nussbaum, Robert L; De Matteis, Maria Antonietta; Dorchies, Olivier M; Scapozza, Leonardo; Wolfer, David Paul; Devuyst, Olivier (2019). OCRL Deficiency Impairs Endolysosomal Function in a Humanized Mouse Model for Lowe Syndrome and Dent Disease. Human Molecular Genetics, 28(12):1931-1946.

Abstract

Mutations in OCRL encoding the inositol polyphosphate 5-phosphatase OCRL (Lowe oculocerebrorenal syndrome protein) disrupt phosphoinositide homeostasis along the endolysosomal pathway causing dysfunction of the cells lining the kidney proximal tubule. The dysfunction can be isolated (Dent disease 2) or associated with congenital cataracts, central hypotonia and intellectual disability (Lowe syndrome). The mechanistic understanding of Dent disease 2/Lowe syndrome remains scarce, due to limitations of animal models of OCRL deficiency.
Here, we investigate the role of OCRL in Dent disease 2/Lowe syndrome by using OcrlY/− mice, where the lethal deletion of the paralogue Inpp5b was rescued by human INPP5B insertion, and primary culture of proximal tubule cells (mPTCs) derived from OcrlY/− kidneys.
The OcrlY/− mice show muscular defects with dysfunctional locomotricity and present massive urinary losses of low-molecular-weight proteins and albumin, caused by selective impairment of receptor-mediated endocytosis in proximal tubule cells. The latter was due to accumulation of phosphatidylinositol 4,5–bisphosphate PI(4,5)P2 in endolysosomes, driving local hyper-polymerization of F-actin and impairing trafficking of the endocytic LRP2 receptor, as evidenced in OcrlY/− mPTCs. The OCRL deficiency was also associated with a disruption of the lysosomal dynamic and proteolytic activity. Partial convergence of disease-mechanism and renal phenotypes observed in OcrlY/− and Clcn5 Y/− mice suggest shared mechanisms in Dent disease 1 and 2.
These studies substantiate the first mouse model of Lowe syndrome and give insights into the role of OCRL in cellular trafficking of multiligand receptors. These insights open new avenues for therapeutic interventions in Lowe syndrome and Dent disease.

Abstract

Mutations in OCRL encoding the inositol polyphosphate 5-phosphatase OCRL (Lowe oculocerebrorenal syndrome protein) disrupt phosphoinositide homeostasis along the endolysosomal pathway causing dysfunction of the cells lining the kidney proximal tubule. The dysfunction can be isolated (Dent disease 2) or associated with congenital cataracts, central hypotonia and intellectual disability (Lowe syndrome). The mechanistic understanding of Dent disease 2/Lowe syndrome remains scarce, due to limitations of animal models of OCRL deficiency.
Here, we investigate the role of OCRL in Dent disease 2/Lowe syndrome by using OcrlY/− mice, where the lethal deletion of the paralogue Inpp5b was rescued by human INPP5B insertion, and primary culture of proximal tubule cells (mPTCs) derived from OcrlY/− kidneys.
The OcrlY/− mice show muscular defects with dysfunctional locomotricity and present massive urinary losses of low-molecular-weight proteins and albumin, caused by selective impairment of receptor-mediated endocytosis in proximal tubule cells. The latter was due to accumulation of phosphatidylinositol 4,5–bisphosphate PI(4,5)P2 in endolysosomes, driving local hyper-polymerization of F-actin and impairing trafficking of the endocytic LRP2 receptor, as evidenced in OcrlY/− mPTCs. The OCRL deficiency was also associated with a disruption of the lysosomal dynamic and proteolytic activity. Partial convergence of disease-mechanism and renal phenotypes observed in OcrlY/− and Clcn5 Y/− mice suggest shared mechanisms in Dent disease 1 and 2.
These studies substantiate the first mouse model of Lowe syndrome and give insights into the role of OCRL in cellular trafficking of multiligand receptors. These insights open new avenues for therapeutic interventions in Lowe syndrome and Dent disease.

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Item Type:Journal Article, refereed, original work
Communities & Collections:04 Faculty of Medicine > Institute of Anatomy
04 Faculty of Medicine > University Hospital Zurich > Ophthalmology Clinic
04 Faculty of Medicine > Institute of Physiology
07 Faculty of Science > Institute of Physiology

04 Faculty of Medicine > Neuroscience Center Zurich
04 Faculty of Medicine > Center for Integrative Human Physiology
Dewey Decimal Classification:570 Life sciences; biology
610 Medicine & health
Uncontrolled Keywords:Genetics(clinical), Genetics, Molecular Biology, General Medicine
Language:English
Date:15 June 2019
Deposited On:15 Jan 2019 14:21
Last Modified:01 Jul 2019 12:03
Publisher:Oxford University Press
ISSN:0964-6906
OA Status:Green
Free access at:PubMed ID. An embargo period may apply.
Publisher DOI:https://doi.org/10.1093/hmg/ddy449
PubMed ID:30590522

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