Genetics
Abstract
Gain-of-function mutations in the WNK1 and WNK4 genes are responsible for Familial Hyperkalemic Hypertension (FHHt), a rare inherited disorder characterized by arterial hypertension and hyperkalemia with metabolic acidosis. More recently, FHHt-causing mutations in the KLHL3-CUL3 E3 ubiquitin ligase complex have shed light on the importance of WNKs cellular degradation on renal ion transport. Using full exome sequencing in a four-generation family and then targeted sequencing in other suspected cases, we have identified new missense variants at the WNK1 gene, clustering in the short conserved acidic motif known to interact with the KLHL3-CUL3 ubiquitin complex. Affected subjects had an early-onset and a marked hyperkalemic phenotype, but normal blood pressure values. Functional experiments in Xenopus laevis oocytes and HEK293T cells demonstrated that these mutations strongly decrease the ubiquitination of the kidney-specific isoform KS-WNK1 by the KLHL3-CUL3 complex, rather than the long ubiquitous catalytically active L-WNK1 isoform. A corresponding CRISPR-Cas9 engineered mouse model recapitulated both the clinical and biological phenotype. Renal investigations showed increased activation of the SPAK-NCC phosphorylation cascade, associated with impaired ROMK apical expression in the distal part of the renal tubule. Altogether, these new WNK1 genetic variants highlight the importance of the KS-WNK1 isoform abundance on potassium homeostasis.
Authors
Helene Louis-Dit-Picard, Ilektra Kouranti, Chloe Rafael, Irmine Loisel-Ferreira, Maria Chavez-Canales, Waed Abdel Khalek, Eduardo Argaiz, Stephanie Baron, Sarah Vacle, Tiffany Migeon, Richard Coleman, Marcio Do Cruzeiro, Marguerite Hureaux, Nirubiah Thurairajasingam, Stéphane Decramer, Xavier Girerd, Kevin M. O'Shaughnessy, Paolo Mulatero, Gwenaelle Roussey, Ivan Tack, Robert J. Unwin, Rosa Vargas-Poussou, Olivier Staub, P. Richard Grimm, Paul A. Welling, Gerardo Gamba, Eric Clauser, Juliette Hadchouel, Xavier Jeunemaitre
Abstract
Males and females differ in body composition and fat distribution. Using a mouse model that segregates gonadal sex (ovaries and testes) from chromosomal sex (XX and XY), we showed that XX chromosome complement in combination with a high-fat diet led to enhanced weight gain in the presence of male or female gonads. We identified the genomic dosage of Kdm5c, an X chromosome gene that escapes X-chromosome inactivation, as a determinant of the X chromosome effect on adiposity. Modulating Kdm5c gene dosage in XX female mice to levels that are normally present in males reduced body weight, fat content, and food intake to a similar degree as altering the entire X chromosome dosage. In cultured preadipocytes, the levels of KDM5C histone demethylase influenced chromatin accessibility (ATAC-seq), gene expression (RNA-seq), and adipocyte differentiation. Both in vitro and in vivo, Kdm5c dosage influenced gene expression involved in extracellular matrix remodeling, which is critical for adipocyte differentiation and adipose tissue expansion. In humans, adipose tissue KDM5C mRNA levels and KDM5C genetic variants were associated with body mass. These studies demonstrate that the sex-dependent dosage of Kdm5c contributes to male/female differences in adipocyte biology, and highlight X-escape genes as a critical component of female physiology.
Authors
Jenny C. Link, Carrie B. Wiese, Xuqi Chen, Rozeta Avetisyan, Emilio Ronquillo, Feiyang Ma, Xiuqing Guo, Jie Yao, Matthew Allison, Yii-Der I. Chen, Jerome I. Rotter, Julia S. El-Sayed Moustafa, Kerrin S. Small, Shigeki Iwase, Matteo Pellegrini, Laurent Vergnes, Arthur P. Arnold, Karen Reue
Abstract
Nearly all breast cancer deaths result from metastatic disease. Despite this, the genomic events that drive metastatic recurrence are poorly understood. We performed whole-exome and shallow whole-genome sequencing to identify genes and pathways preferentially mutated or copy-number altered in metastases compared with the paired primary tumors from which they arose. Seven genes were preferentially mutated in metastases — MYLK, PEAK1, SLC2A4RG, EVC2, XIRP2, PALB2, and ESR1 — 5 of which are not significantly mutated in any type of human primary cancer. Four regions were preferentially copy-number altered: loss of STK11 and CDKN2A/B, as well as gain of PTK6 and the membrane-bound progesterone receptor, PAQR8. PAQR8 gain was mutually exclusive with mutations in the nuclear estrogen and progesterone receptors, suggesting a role in treatment resistance. Several pathways were preferentially mutated or altered in metastases, including mTOR, CDK/RB, cAMP/PKA, WNT, HKMT, and focal adhesion. Immunohistochemical analyses revealed that metastases preferentially inactivate pRB, upregulate the mTORC1 and WNT signaling pathways, and exhibit nuclear localization of activated PKA. Our findings identify multiple therapeutic targets in metastatic recurrence that are not significantly mutated in primary cancers, implicate membrane progesterone signaling and nuclear PKA in metastatic recurrence, and provide genomic bases for the efficacy of mTORC1, CDK4/6, and PARP inhibitors in metastatic breast cancer.
Authors
Matt R. Paul, Tien-chi Pan, Dhruv K. Pant, Natalie N.C. Shih, Yan Chen, Kyra L. Harvey, Aaron Solomon, David Lieberman, Jennifer J.D. Morrissette, Danielle Soucier-Ernst, Noah G. Goodman, S. William Stavropoulos, Kara N. Maxwell, Candace Clark, George K. Belka, Michael Feldman, Angela DeMichele, Lewis A. Chodosh
Abstract
The congenital sideroblastic anemias (CSAs) can be caused by primary defects in mitochondrial iron-sulfur cluster (Fe-S) biogenesis. HSCB (heat shock cognate B), which encodes a mitochondrial co-chaperone, also known as HSC20 (heat shock cognate protein 20), is the partner of mitochondrial heat shock protein A9 (HSPA9). Together with glutaredoxin 5 (GLRX5), HSCB and HSPA9 facilitate the transfer of nascent two-iron, two-sulfur ([2Fe-2S]) clusters to recipient mitochondrial proteins. Mutations in both HSPA9 and GLRX5 have previously been associated with CSA. Therefore, we hypothesized that mutations in HSCB could also cause CSA. We screened patients with genetically undefined CSA and identified a frameshift mutation and a rare promoter variant in HSCB in a female patient with non-syndromic CSA. We found that HSCB expression was decreased in patient-derived fibroblasts and K562 erythroleukemia cells engineered to have the patient-specific promoter variant. Furthermore, gene knockdown and deletion experiments performed in K562 cells, zebrafish, and mice demonstrate that loss of HSCB results in impaired Fe-S cluster biogenesis, a defect in red blood cell hemoglobinization, the development of siderocytes, and more broadly perturbs hematopoiesis in vivo. These results further affirm the involvement of Fe-S biogenesis in erythropoiesis and hematopoiesis and define HSCB as a CSA gene.
Authors
Andrew Crispin, Chaoshe Guo, Caiyong Chen, Dean R. Campagna, Paul J. Schmidt, Daniel A. Lichtenstein, Chang Cao, Anoop K. Sendamarai, Gordon J. Hildick-Smith, Nicholas C. Huston, Jeanne Boudreaux, Sylvia S. Bottomley, Matthew M. Heeney, Barry H. Paw, Mark D. Fleming, Sarah Ducamp
Abstract
Mechanisms driving tumor progression from less aggressive subtypes to more aggressive states represent key targets for therapy. We identified a subset of Luminal A primary breast tumors to give rise to HER2-enriched (HER2E) subtype metastases, but remain clinically HER2 negative (cHER2-). By testing the unique genetic and transcriptomic features of these cases, we developed the hypothesis FGFR4 likely participates in this subtype switching. To evaluate this, we developed two FGFR4 genomic signatures using a PDX model treated with a FGFR4 inhibitor, which inhibited PDX growth in vivo. Bulk tumor gene expression analysis and single cell RNAseq demonstrated that the inhibition of FGFR4 signaling caused molecular switching. In the METABRIC breast cancer cohort,FGFR4-induced and FGFR4-repressed signatures each predicted overall survival. Additionally, FGFR4-induced signature was also an independent prognostic factor beyond subtype and stage. Supervised analysis of 77 primary tumors with paired metastasis revealed that the FGFR4-induced signature was significantly higher in luminal/ER+ tumor metastases compared with their primaries. Finally, multivariate analysis demonstrated that the FGFR4-induced signature also predicted site-specific metastasis for lung, liver and brain, but not for bone or lymph nodes. These data identify a link between FGFR4-regulated genes and metastasis, suggesting treatment options for FGFR4-positive patients, whose high expression is not caused by mutation or amplification.
Authors
Susana Garcia-Recio, Aatish Thennavan, Michael P. East, Joel S. Parker, Juan M. Cejalvo, Joseph P. Garay, Daniel P. Hollern, Xiaping He, Kevin R. Mott, Patricia Galván, Cheng Fan, Sara R. Selitsky, Alisha R. Coffey, David Marron, Fara Brasó-Maristany, Octavio Burgues, Joan Albanell, Federico Rojo, Ana Lluch, Eduardo Martinez de Dueñas, Jeffrey M. Rosen, Gary L. Johnson, Lisa A. Carey, Aleix Prat, Charles M. Perou
Abstract
The biology of harlequin ichthyosis (HI), a devastating skin disorder, caused by loss of function mutations in the gene ABCA12, is poorly understood and to date no satisfactory treatment has been developed. We sought to investigate pathomechanisms of HI which could lead to the identification of new treatments to improve patients’ quality of life. In this study, RNA-Seq and functional assays were performed to define the effects of loss of ABCA12, using HI patient skin samples and an engineered CRISPR-Cas9 ABCA12 KO cell line. The HI living skin equivalent (3D model) recapitulated the HI skin phenotype. The cytokines IL-36α and IL-36γ were upregulated in HI skin whereas the innate immune inhibitor, IL-37, was strongly downregulated. We also identified STAT1 and its downstream target inducible nitric oxide synthase (NOS2) to be upregulated in the in vitro HI 3D model and HI patient skin samples. Inhibition of NOS2 using the inhibitor, 1400W, or the JAK inhibitor, tofacitinib, dramatically improved the in vitro HI phenotype by restoring the lipid barrier in the HI 3D model. Our study has identified dysregulated pathways in HI skin that are feasible therapeutic targets.
Authors
Florence Enjalbert, Priya Dewan, Matthew P. Caley, Eleri M. Jones, Mary A. Morse, David P. Kelsell, Anton J. Enright, Edel A. O'Toole
Abstract
Attention deficit/hyperactivity disorder (ADHD) is a common and heritable phenotype frequently accompanied by insomnia, anxiety, and depression. Here, using a reverse phenotyping approach, we report heterozygous coding variations in the core circadian clock gene cryptochrome 1 in 15 unrelated multigenerational families with combined ADHD and insomnia. The variants led to functional alterations in the circadian molecular rhythms, providing a mechanistic link to the behavioral symptoms. One variant, CRY1Δ11 c.1657+3A>C, is present in approximately 1% of Europeans, therefore standing out as a diagnostic and therapeutic marker. We showed by exome sequencing in an independent cohort of patients with combined ADHD and insomnia that 8 of 62 patients and 0 of 369 controls carried CRY1Δ11. Also, we identified a variant, CRY1Δ6 c.825+1G>A, that shows reduced affinity for BMAL1/CLOCK and causes an arrhythmic phenotype. Genotype-phenotype correlation analysis revealed that this variant segregated with ADHD and delayed sleep phase disorder (DSPD) in the affected family. Finally, we found in a phenome-wide association study involving 9438 unrelated adult Europeans that CRY1Δ11 was associated with major depressive disorder, insomnia, and anxiety. These results defined a distinctive group of circadian psychiatric phenotypes that we propose to designate as “circiatric” disorders.
Authors
O. Emre Onat, M. Ece Kars, Şeref Gül, Kaya Bilguvar, Yiming Wu, Ayşe Özhan, Cihan Aydın, A. Nazlı Başak, M. Allegra Trusso, Arianna Goracci, Chiara Fallerini, Alessandra Renieri, Jean-Laurent Casanova, Yuval Itan, Cem E. Atbaşoğlu, Meram C. Saka, İ. Halil Kavaklı, Tayfun Özçelik
Abstract
Leber’s hereditary optic neuropathy (LHON) is a maternally inherited eye disease. X-linked nuclear modifiers were proposed to modify the phenotypic manifestation of LHON-associated mitochondrial DNA (mtDNA) mutations. By whole exome sequencing, we identified the X-linked LHON modifier (c.157C>T, p. Arg53Trp) in the PRICKLE3 encoding a mitochondrial protein linked to biogenesis of ATPase in three Chinese families. All affected individuals carried both ND4 11778G>A and p.Arg53Trp mutations, while subjects bearing only single mutation exhibited normal vision. The cells carrying the p.Arg53Trp mutation exhibited the defective assembly, stability and function of ATP synthase, verified by PRICKLE3 knock-down cells. Co-immunoprecipitation indicated the direct interaction of PRICKLE3 with ATP synthase via ATP8. Strikingly, mutant cells bearing both p.Arg53Trp and m.11778G>A mutations displayed greater mitochondrial dysfunctions than those carrying only single mutation. These indicated that the p.Arg53Trp mutation acted in synergy with m.11778G>A mutation and deteriorated mitochondrial dysfunctions necessary for the expression of LHON. Furthermore, we demonstrated that Prickle3 deficient mice exhibited the pronounced ATPase deficiencies. Prickle3 knock-out mice recapitulated LHON phenotypes with retina deficiencies including degeneration of retinal ganglion cells and abnormal vasculature. Our findings provided new insights into pathophysiology of LHON that were manifested by interaction between mtDNA mutation and X-linked nuclear modifier.
Authors
Jialing Yu, Xiaoyang Liang, Yanchun Ji, Cheng Ai, Junxia Liu, Ling Zhu, Zhipeng Nie, Xiaofen Jin, Chenghui Wang, Juanjuan Zhang, Fuxin Zhao, Shuang Mei, Xiaoxu Zhao, Xiangtian Zhou, Minglian Zhang, Meng Wang, Taosheng Huang, Pingping Jiang, Min-Xin Guan
Abstract
Joubert syndrome (JBTS) is a recessive neurodevelopmental ciliopathy, characterized by a pathognomonic hindbrain malformation. All known JBTS-genes encode proteins involved in the structure or function of primary cilia, ubiquitous antenna-like organelles essential for cellular signal transduction. Here, we use the recently identified JBTS-associated protein ARMC9 in tandem-affinity purification and yeast two-hybrid screens to identify a novel ciliary module whose dysfunction underlies JBTS. In addition to known JBTS-associated proteins CEP104 and CSPP1, we identify CCDC66 and TOGARAM1 as ARMC9 interaction partners. We show that TOGARAM1 variants cause JBTS and disrupt TOGARAM1 interaction with ARMC9. Using a combination of protein interaction analyses and characterization of patient-derived fibroblasts, CRISPR/Cas9-engineered zebrafish and hTERT-RPE1 cells, we demonstrate that dysfunction of ARMC9 or TOGARAM1 results in short cilia with decreased axonemal acetylation and polyglutamylation, but relatively intact transition zone function. Aberrant cold- and serum-induced ciliary loss in both ARMC9 and TOGARAM1 patient cell lines suggests a role for this new JBTS-associated protein module in ciliary stability.
Authors
Brooke L. Latour, Julie C. Van De Weghe, Tamara D.S. Rusterholz, Stef J.F. Letteboer, Arianna Gomez, Ranad Shaheen, Matthias Gesemann, Arezou Karamzade, Mostafa Asadollahi, Miguel Barroso-Gil, Manali Chitre, Megan E. Grout, Jeroen van Reeuwijk, Sylvia E.C. van Beersum, Caitlin V. Miller, Jennifer C. Dempsey, Heba Morsy, Michael J. Bamshad, Deborah A. Nickerson, Stephan C.F. Neuhauss, Karsten Boldt, Marius Ueffing, Mohammad Keramatipour, John A. Sayer, Fowzan S. Alkuraya, Ruxandra Bachmann-Gagescu, Ronald Roepman, Dan Doherty
Abstract
The transcription factor ISL1 is expressed in pituitary gland stem cells and the thyrotrope and gonadotrope lineages. Pituitary-specific Isl1 deletion causes hypopituitarism with increased stem cell apoptosis, reduced differentiation of thyrotropes and gonadotropes, and reduced body size. Conditional Isl1 deletion causes development of multiple Rathke’s cleft-like cysts, with 100% penetrance. Foxa1 and Foxj1 are abnormally expressed in the pituitary gland and associated with a ciliogenic gene expression program in the cysts. We confirmed expression of FOXA1, FOXJ1 and stem cell markers in human Rathke's cleft cyst tissue, but not craniopharyngiomas, which suggests these transcription factors are useful, pathological markers for diagnosis of Rathke's cleft cysts. These studies support a model whereby expression of ISL1 in pituitary progenitors drives differentiation into thyrotropes and gonadotropes, and without it, activation of FOXA1 and FOXJ1 permits development of an oral epithelial cell fate with mucinous cysts. This pituitary specific Isl1 mouse knockout sheds light on the etiology of Rathke's cleft cysts and the role of ISL1 in normal pituitary development.
Authors
Michelle L. Brinkmeier, Hironori Bando, Adriana C. Camarano, Shingo Fujio, Koji Yoshimoto, Flávio S. J. de Souza, Sally A. Camper
Copyright © 2021 American Society for Clinical Investigation
ISSN: 0021-9738 (print), 1558-8238 (online)