Mutations in multiple components of the nuclear pore complex cause nephrotic syndrome
Daniela A. Braun, … , Mustafa K. Khokha, Friedhelm Hildebrandt
Daniela A. Braun, … , Mustafa K. Khokha, Friedhelm Hildebrandt
Published October 1, 2018; First published September 4, 2018
Citation Information: J Clin Invest. 2018;128(10):4313-4328. https://doi.org/10.1172/JCI98688.
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Research Article Genetics Nephrology

Mutations in multiple components of the nuclear pore complex cause nephrotic syndrome

Abstract

Steroid-resistant nephrotic syndrome (SRNS) almost invariably progresses to end-stage renal disease. Although more than 50 monogenic causes of SRNS have been described, a large proportion of SRNS remains unexplained. Recently, it was discovered that mutations of NUP93 and NUP205, encoding 2 proteins of the inner ring subunit of the nuclear pore complex (NPC), cause SRNS. Here, we describe mutations in genes encoding 4 components of the outer rings of the NPC, namely NUP107, NUP85, NUP133, and NUP160, in 13 families with SRNS. Using coimmunoprecipitation experiments, we showed that certain pathogenic alleles weakened the interaction between neighboring NPC subunits. We demonstrated that morpholino knockdown of nup107, nup85, or nup133 in Xenopus disrupted glomerulogenesis. Re-expression of WT mRNA, but not of mRNA reflecting mutations from SRNS patients, mitigated this phenotype. We furthermore found that CRISPR/Cas9 knockout of NUP107, NUP85, or NUP133 in podocytes activated Cdc42, an important effector of SRNS pathogenesis. CRISPR/Cas9 knockout of nup107 or nup85 in zebrafish caused developmental anomalies and early lethality. In contrast, an in-frame mutation of nup107 did not affect survival, thus mimicking the allelic effects seen in humans. In conclusion, we discovered here that mutations in 4 genes encoding components of the outer ring subunits of the NPC cause SRNS and thereby provide further evidence that specific hypomorphic mutations in these essential genes cause a distinct, organ-specific phenotype.

Authors

Daniela A. Braun, Svjetlana Lovric, David Schapiro, Ronen Schneider, Jonathan Marquez, Maria Asif, Muhammad Sajid Hussain, Ankana Daga, Eugen Widmeier, Jia Rao, Shazia Ashraf, Weizhen Tan, C. Patrick Lusk, Amy Kolb, Tilman Jobst-Schwan, Johanna Magdalena Schmidt, Charlotte A. Hoogstraten, Kaitlyn Eddy, Thomas M. Kitzler, Shirlee Shril, Abubakar Moawia, Kathrin Schrage, Arwa Ishaq A. Khayyat, Jennifer A. Lawson, Heon Yung Gee, Jillian K. Warejko, Tobias Hermle, Amar J. Majmundar, Hannah Hugo, Birgit Budde, Susanne Motameny, Janine Altmüller, Angelika Anna Noegel, Hanan M. Fathy, Daniel P. Gale, Syeda Seema Waseem, Ayaz Khan, Larissa Kerecuk, Seema Hashmi, Nilufar Mohebbi, Robert Ettenger, Erkin Serdaroğlu, Khalid A. Alhasan, Mais Hashem, Sara Goncalves, Gema Ariceta, Mercedes Ubetagoyena, Wolfram Antonin, Shahid Mahmood Baig, Fowzan S. Alkuraya, Qian Shen, Hong Xu, Corinne Antignac, Richard P. Lifton, Shrikant Mane, Peter Nürnberg, Mustafa K. Khokha, Friedhelm Hildebrandt

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Figure 1

Homozygosity mapping and whole exome sequencing identify recessive mutations of NUP107, NUP85, and NUP133 in 12 families with steroid-resistant nephrotic syndrome.

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Homozygosity mapping and whole exome sequencing identify recessive mutat...
(A) Renal histology of individual A3825-21 (NUP107 mutation) shows diffuse mesangial sclerosis on light microscopy. (B, F, and I) Exon structure of human cDNAs. Positions of start codons and of stop codon are indicated. For protein domain structures, α-helices are depicted as red zigzag lines and β-turns as purple arrows. Arrows indicate positions of pathogenic mutations detected in families with SRNS. H, homozygous; h, heterozygous. (B) Exon structure, protein domain structure, and human mutations of NUP107. (C) Homozygosity mapping identifies 3 recessive candidate loci (red circles) in patient A4649-21. Nonparametric lod (NPL) scores and SNP positions (Affymetrix 250K StyI array) are plotted on human chromosomes concatenated from p-ter (left) to q-ter (right). Genetic distance is given in centimorgans (cM). Whole exome sequencing identifies a homozygous mutation of NUP107 (p.Met101Ile) that is positioned within the maximum NPL peak on chromosome 12 (arrowhead). (D, G, and K) Evolutionary conservation of amino acid residues that are altered in patients with SRNS. (D) Altered amino acid residues of NUP107 (p.Met101Ile, p.Tyr889Cys). (E) Renal histology of A3259-21 (NUP85 mutation) showing podocyte foot process effacement on transmission electron microscopy (TEM) (arrowheads). (F) Exon structure, protein domain structure, and human mutations of NUP85. (G) Altered amino acid residues of NUP85 (p.Ala477Val, p.Ala581Pro, p.Arg645Trp). (H) Renal histology of individual F797-21 (NUP133 mutation) shows podocyte foot process effacement on TEM (arrowheads). (I) Exon structure, protein domain structure, and human mutations of NUP133. (J) Homozygosity mapping in individual F797-21 identifies regions of homozygosity as recessive candidate loci. Within the maximum NPL peak on chromosome 1 (arrowhead), we identified a homozygous mutation in NUP133 (p.Ser974Arg). (K) Altered amino acid residues of NUP133 (p.Arg231Gly, p.Ser974Arg, p.Leu1055Ser).