Authors:	Nagel-Wolfrum, Kerstin Fadl, Benjamin R. Becker, Mirjana M. Wunderlich, Kirsten A. Schäfer, Jessica Sturm, Daniel Fritze, Jacques Gür, Burcu Kaplan, Lew Andreani, Tommaso Goldmann, Tobias Brooks, Matthew Starostik, Margaret R. Lokhande, Anagha Apel, Melissa Fath, Karl R Stingl, Katarina Kohl, Susanne DeAngelis, Margaret M. Schlötzer-Schrehardt, Ursula Kim, Ivana K. Owen, Leah A. Vetter, Jan M. Pfeiffer, Norbert Andrade-Navarro, Miguel A. Grosche, Antje Swaroop, Anand Wolfrum, Uwe
Title:	Expression and subcellular localization of USH1C/harmonin in human retina provides insights into pathomechanisms and therapy
Online publication date:	9-May-2023
Year of first publication:	2023
Language:	english
Abstract:	Usher syndrome (USH) is the most common form of hereditary deaf-blindness in humans. USH is a complex genetic disorder, assigned to three clinical subtypes differing in onset, course and severity, with USH1 being the most severe. Rodent USH1 models do not reflect the ocular phenotype observed in human patients to date; hence, little is known about the pathophysiology of USH1 in the human eye. One of the USH1 genes, USH1C, exhibits extensive alternative splicing and encodes numerous harmonin protein isoforms that function as scaffolds for organizing the USH interactome. RNA-seq analysis of human retinae uncovered harmonin_a1 as the most abundant transcript of USH1C. Bulk RNA-seq analysis and immunoblotting showed abundant expression of harmonin in Müller glia cells (MGCs) and retinal neurons. Furthermore, harmonin was localized in the terminal endfeet and apical microvilli of MGCs, presynaptic region (pedicle) of cones and outer segments (OS) of rods as well as at adhesive junctions between MGCs and photoreceptor cells (PRCs) in the outer limiting membrane (OLM). Our data provide evidence for the interaction of harmonin with OLM molecules in PRCs and MGCs and rhodopsin in PRCs. Subcellular expression and colocalization of harmonin correlate with the clinical phenotype observed in USH1C patients. We also demonstrate that primary cilia defects in USH1C patient-derived fibroblasts could be reverted by the delivery of harmonin_a1 transcript isoform. Our studies thus provide novel insights into PRC cell biology, USH1C pathophysiology and development of gene therapy treatment(s).
DDC:	570 Biowissenschaften 570 Life sciences
Institution:	Johannes Gutenberg-Universität Mainz
Department:	FB 10 Biologie
Place:	Mainz
ROR:	https://ror.org/023b0x485
DOI:	http://doi.org/10.25358/openscience-9073
Version:	Published version
Publication type:	Zeitschriftenaufsatz
Document type specification:	Scientific article
License:	CC BY-NC
Information on rights of use:	https://creativecommons.org/licenses/by-nc/4.0/
Journal:	Human Molecular Genetics 32 3
Pages or article number:	431 449
Publisher:	Oxford University Press
Publisher place:	Oxford
Issue date:	2023
ISSN:	1460-2083
Publisher DOI:	10.1093/hmg/ddac211
Appears in collections:	DFG-491381577-H