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Mechakra A, Footz T, Walter M, Aránega A, Hernández-Torres F, Morel E, Millat G, Yang YQ, Chahine M, Chevalier P, Christé G. A Novel PITX2c Gain-of-Function Mutation, p.Met207Val, in Patients With Familial Atrial Fibrillation. Am J Cardiol 2019; 123:787-793. [PMID: 30558760 DOI: 10.1016/j.amjcard.2018.11.047] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/20/2018] [Revised: 11/16/2018] [Accepted: 11/20/2018] [Indexed: 01/08/2023]
Abstract
Genome-wide studies have associated several genetic variants upstream of PITX2 on chromosome 4q25 with atrial fibrillation (AF), suggesting a potential role of PITX2 in AF. Our study aimed at identifying rare coding variants in PITX2 predisposing to AF. The Polymerase chain reaction sequencing of PITX2c was performed in 60 unrelated patients with idiopathic AF. The p.Met207Val variant was identified in 1 of 60 French patients with early onset AF and in none of 389 French referents. This variant, located in the inhibitory domain 1 distal to the homeodomain, was evaluated by the software MutationTaster as a disease-causing mutation with a probability of 0.999. Reporter gene assays demonstrated that p.Met207Val caused a 3.1-fold increase in transactivation activity of PITX2c in HeLa cells in comparison with its wild-type counterpart. When the variant was coexpressed with wild-type PITX2c in the HL-1 immortalized mouse atrial cell line, this gain-of-function caused an increase in the mRNA level of KCNH2 (2.6-fold), SCN1B (1.9-fold), GJA5 (3.1-fold), GJA1 (2.1-fold), and KCNQ1 in the homozygous form (1.8-fold). These genes encode for the IKr channel α subunit, the β-1 Na+ channel subunit, connexin 40, connexin 43 and the IKs channel α subunit, respectively. These conditions may contribute to the propensity to AF found in patients carrying the p.Met207Val variant. In conclusion, the present report is the first to associate a gain-of-function mutation of PITX2c with increased vulnerability to AF, therefore, restoration of normal PITX2c function may be a potential therapeutic target in AF patients.
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Affiliation(s)
- Asma Mechakra
- EA4612 Neurocardiologie, Université Lyon 1, Lyon, France
| | - Tim Footz
- Department of Medical Genetics, University of Alberta, Edmonton, Alberta, Canada
| | - Michael Walter
- Department of Medical Genetics, University of Alberta, Edmonton, Alberta, Canada
| | - Amelia Aránega
- Department of Experimental Biology, Faculty of Experimental Sciences, University of Jaén, Jaén, Spain
| | | | - Elodie Morel
- EA4612 Neurocardiologie, Université Lyon 1, Lyon, France
| | - Gilles Millat
- EA4612 Neurocardiologie, Université Lyon 1, Lyon, France
| | - Yi-Qing Yang
- Department of Cardiology, La-boratory of Cardiovascular Research and Central Laboratory, Shanghai Chest Hospital, Shanghai Jiao Tong University, Shanghai, China
| | - Mohamed Chahine
- Institut Universitaire en Santé Mentale, Québec City, Québec, Canada
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Fang Q, George AS, Brinkmeier ML, Mortensen AH, Gergics P, Cheung LYM, Daly AZ, Ajmal A, Pérez Millán MI, Ozel AB, Kitzman JO, Mills RE, Li JZ, Camper SA. Genetics of Combined Pituitary Hormone Deficiency: Roadmap into the Genome Era. Endocr Rev 2016; 37:636-675. [PMID: 27828722 PMCID: PMC5155665 DOI: 10.1210/er.2016-1101] [Citation(s) in RCA: 107] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/19/2016] [Accepted: 10/31/2016] [Indexed: 02/08/2023]
Abstract
The genetic basis for combined pituitary hormone deficiency (CPHD) is complex, involving 30 genes in a variety of syndromic and nonsyndromic presentations. Molecular diagnosis of this disorder is valuable for predicting disease progression, avoiding unnecessary surgery, and family planning. We expect that the application of high throughput sequencing will uncover additional contributing genes and eventually become a valuable tool for molecular diagnosis. For example, in the last 3 years, six new genes have been implicated in CPHD using whole-exome sequencing. In this review, we present a historical perspective on gene discovery for CPHD and predict approaches that may facilitate future gene identification projects conducted by clinicians and basic scientists. Guidelines for systematic reporting of genetic variants and assigning causality are emerging. We apply these guidelines retrospectively to reports of the genetic basis of CPHD and summarize modes of inheritance and penetrance for each of the known genes. In recent years, there have been great improvements in databases of genetic information for diverse populations. Some issues remain that make molecular diagnosis challenging in some cases. These include the inherent genetic complexity of this disorder, technical challenges like uneven coverage, differing results from variant calling and interpretation pipelines, the number of tolerated genetic alterations, and imperfect methods for predicting pathogenicity. We discuss approaches for future research in the genetics of CPHD.
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Affiliation(s)
- Qing Fang
- Department of Human Genetics (Q.F., A.S.G., M.L.B., A.H.M., P.G., L.Y.M.C., A.Z.D., M.I.P.M., A.B.O., J.O.K., R.E.M., J.Z.L., S.A.C.), Graduate Program in Bioinformatics (A.S.G.), Endocrine Division, Department of Internal Medicine (A.A.), and Department of Computational Medicine and Bioinformatics (J.O.K., R.E.M., J.Z.L.), University of Michigan, Ann Arbor, Michigan 48109
| | - Akima S George
- Department of Human Genetics (Q.F., A.S.G., M.L.B., A.H.M., P.G., L.Y.M.C., A.Z.D., M.I.P.M., A.B.O., J.O.K., R.E.M., J.Z.L., S.A.C.), Graduate Program in Bioinformatics (A.S.G.), Endocrine Division, Department of Internal Medicine (A.A.), and Department of Computational Medicine and Bioinformatics (J.O.K., R.E.M., J.Z.L.), University of Michigan, Ann Arbor, Michigan 48109
| | - Michelle L Brinkmeier
- Department of Human Genetics (Q.F., A.S.G., M.L.B., A.H.M., P.G., L.Y.M.C., A.Z.D., M.I.P.M., A.B.O., J.O.K., R.E.M., J.Z.L., S.A.C.), Graduate Program in Bioinformatics (A.S.G.), Endocrine Division, Department of Internal Medicine (A.A.), and Department of Computational Medicine and Bioinformatics (J.O.K., R.E.M., J.Z.L.), University of Michigan, Ann Arbor, Michigan 48109
| | - Amanda H Mortensen
- Department of Human Genetics (Q.F., A.S.G., M.L.B., A.H.M., P.G., L.Y.M.C., A.Z.D., M.I.P.M., A.B.O., J.O.K., R.E.M., J.Z.L., S.A.C.), Graduate Program in Bioinformatics (A.S.G.), Endocrine Division, Department of Internal Medicine (A.A.), and Department of Computational Medicine and Bioinformatics (J.O.K., R.E.M., J.Z.L.), University of Michigan, Ann Arbor, Michigan 48109
| | - Peter Gergics
- Department of Human Genetics (Q.F., A.S.G., M.L.B., A.H.M., P.G., L.Y.M.C., A.Z.D., M.I.P.M., A.B.O., J.O.K., R.E.M., J.Z.L., S.A.C.), Graduate Program in Bioinformatics (A.S.G.), Endocrine Division, Department of Internal Medicine (A.A.), and Department of Computational Medicine and Bioinformatics (J.O.K., R.E.M., J.Z.L.), University of Michigan, Ann Arbor, Michigan 48109
| | - Leonard Y M Cheung
- Department of Human Genetics (Q.F., A.S.G., M.L.B., A.H.M., P.G., L.Y.M.C., A.Z.D., M.I.P.M., A.B.O., J.O.K., R.E.M., J.Z.L., S.A.C.), Graduate Program in Bioinformatics (A.S.G.), Endocrine Division, Department of Internal Medicine (A.A.), and Department of Computational Medicine and Bioinformatics (J.O.K., R.E.M., J.Z.L.), University of Michigan, Ann Arbor, Michigan 48109
| | - Alexandre Z Daly
- Department of Human Genetics (Q.F., A.S.G., M.L.B., A.H.M., P.G., L.Y.M.C., A.Z.D., M.I.P.M., A.B.O., J.O.K., R.E.M., J.Z.L., S.A.C.), Graduate Program in Bioinformatics (A.S.G.), Endocrine Division, Department of Internal Medicine (A.A.), and Department of Computational Medicine and Bioinformatics (J.O.K., R.E.M., J.Z.L.), University of Michigan, Ann Arbor, Michigan 48109
| | - Adnan Ajmal
- Department of Human Genetics (Q.F., A.S.G., M.L.B., A.H.M., P.G., L.Y.M.C., A.Z.D., M.I.P.M., A.B.O., J.O.K., R.E.M., J.Z.L., S.A.C.), Graduate Program in Bioinformatics (A.S.G.), Endocrine Division, Department of Internal Medicine (A.A.), and Department of Computational Medicine and Bioinformatics (J.O.K., R.E.M., J.Z.L.), University of Michigan, Ann Arbor, Michigan 48109
| | - María Ines Pérez Millán
- Department of Human Genetics (Q.F., A.S.G., M.L.B., A.H.M., P.G., L.Y.M.C., A.Z.D., M.I.P.M., A.B.O., J.O.K., R.E.M., J.Z.L., S.A.C.), Graduate Program in Bioinformatics (A.S.G.), Endocrine Division, Department of Internal Medicine (A.A.), and Department of Computational Medicine and Bioinformatics (J.O.K., R.E.M., J.Z.L.), University of Michigan, Ann Arbor, Michigan 48109
| | - A Bilge Ozel
- Department of Human Genetics (Q.F., A.S.G., M.L.B., A.H.M., P.G., L.Y.M.C., A.Z.D., M.I.P.M., A.B.O., J.O.K., R.E.M., J.Z.L., S.A.C.), Graduate Program in Bioinformatics (A.S.G.), Endocrine Division, Department of Internal Medicine (A.A.), and Department of Computational Medicine and Bioinformatics (J.O.K., R.E.M., J.Z.L.), University of Michigan, Ann Arbor, Michigan 48109
| | - Jacob O Kitzman
- Department of Human Genetics (Q.F., A.S.G., M.L.B., A.H.M., P.G., L.Y.M.C., A.Z.D., M.I.P.M., A.B.O., J.O.K., R.E.M., J.Z.L., S.A.C.), Graduate Program in Bioinformatics (A.S.G.), Endocrine Division, Department of Internal Medicine (A.A.), and Department of Computational Medicine and Bioinformatics (J.O.K., R.E.M., J.Z.L.), University of Michigan, Ann Arbor, Michigan 48109
| | - Ryan E Mills
- Department of Human Genetics (Q.F., A.S.G., M.L.B., A.H.M., P.G., L.Y.M.C., A.Z.D., M.I.P.M., A.B.O., J.O.K., R.E.M., J.Z.L., S.A.C.), Graduate Program in Bioinformatics (A.S.G.), Endocrine Division, Department of Internal Medicine (A.A.), and Department of Computational Medicine and Bioinformatics (J.O.K., R.E.M., J.Z.L.), University of Michigan, Ann Arbor, Michigan 48109
| | - Jun Z Li
- Department of Human Genetics (Q.F., A.S.G., M.L.B., A.H.M., P.G., L.Y.M.C., A.Z.D., M.I.P.M., A.B.O., J.O.K., R.E.M., J.Z.L., S.A.C.), Graduate Program in Bioinformatics (A.S.G.), Endocrine Division, Department of Internal Medicine (A.A.), and Department of Computational Medicine and Bioinformatics (J.O.K., R.E.M., J.Z.L.), University of Michigan, Ann Arbor, Michigan 48109
| | - Sally A Camper
- Department of Human Genetics (Q.F., A.S.G., M.L.B., A.H.M., P.G., L.Y.M.C., A.Z.D., M.I.P.M., A.B.O., J.O.K., R.E.M., J.Z.L., S.A.C.), Graduate Program in Bioinformatics (A.S.G.), Endocrine Division, Department of Internal Medicine (A.A.), and Department of Computational Medicine and Bioinformatics (J.O.K., R.E.M., J.Z.L.), University of Michigan, Ann Arbor, Michigan 48109
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3
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Moazzeni H, Akbari MT, Yazdani S, Elahi E. Expression of CXCL6 and BBS5 that may be glaucoma relevant genes is regulated by PITX2. Gene 2016; 593:76-83. [PMID: 27520585 DOI: 10.1016/j.gene.2016.08.019] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2016] [Revised: 07/31/2016] [Accepted: 08/08/2016] [Indexed: 12/26/2022]
Abstract
The transcription factor PITX2 is implicated in glaucoma pathology. In an earlier study we had used microarray analysis to identify genes in the trabecular meshwork (TM) that are affected by knock down of PITX2. Here, those studies were pursued to identify genes that are direct targets of PITX2 and that may be relevant to glaucoma. Initially, bioinformatics tools were used to select among the genes that had been affected by PITX2 knock down those that have PITX2 binding sites and that may be involved in glaucoma related functions. Subsequently, the effect of PITX2 was tested using the dual luciferase assay in four cell cultures including two primary TM cultures co-transfected with vectors containing promoter fragments of six candidate genes upstream of a luciferase gene and a vector that expressed PITX2. Finally, the effect of PITX2 on endogenous expression of two genes was assessed by over expression and knock down of PITX2 in TM cells. Thirty four genes were found to contain PITX2 binding sites in their putative promoter regions, and 16 were found to be associated with TM-specific and/or glaucoma associated functions. Results of dual luciferase assays confirmed that two of six genes tested were directly targeted by PITX2. The two genes were CXCL6 (chemokine (C-X-C motif) ligand 6) and BBS5 (Bardet-Biedl syndrome 5). Over expression and knock down of PITX2 showed that this transcription factor affects endogenous expression of these two genes in TM cells. CXCL6 encodes a pro-inflammatory cytokine, and many studies have suggested that cytokines and other immune system functions are involved in glaucoma pathogenesis. BBS5 is a member of the BBS family of genes that affect ciliary functions, and ciliary bodies in the anterior chamber of the eye produce the aqueous fluid that affects intraocular pressure. Immune related functions and intraocular pressure are both important components of glaucoma pathology. The role of PITX2 in glaucoma may be mediated partly by regulating the expression of CXCL6 and BBS5 and thus affecting immune functions and intraocular pressure.
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Affiliation(s)
- Hamidreza Moazzeni
- Department of Medical Genetics, Faculty of Medical Sciences, Tarbiat Modares University, P.O. Box. 14115-331, Tehran, Iran
| | - Mohammad Taghi Akbari
- Department of Medical Genetics, Faculty of Medical Sciences, Tarbiat Modares University, P.O. Box. 14115-331, Tehran, Iran.
| | - Shahin Yazdani
- Ophthalmic Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Elahe Elahi
- School of Biology, College of Science, University of Tehran, Tehran, Iran; Department of Biotechnology, College of Science, University of Tehran, Tehran, Iran.
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Mao M, Smith RS, Alavi MV, Marchant JK, Cosma M, Libby RT, John SWM, Gould DB. Strain-Dependent Anterior Segment Dysgenesis and Progression to Glaucoma in Col4a1 Mutant Mice. Invest Ophthalmol Vis Sci 2016; 56:6823-31. [PMID: 26567795 DOI: 10.1167/iovs.15-17527] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
PURPOSE Mutations in the gene encoding collagen type IV alpha 1 (COL4A1) cause multisystem disorders including anterior segment dysgenesis (ASD) and optic nerve hypoplasia. The penetrance and severity of individual phenotypes depends on genetic context. Here, we tested the effects of a Col4a1 mutation in two different genetic backgrounds to compare how genetic context influences ocular dysgenesis, IOP, and progression to glaucoma. METHODS Col4a1 mutant mice maintained on a C57BL/6J background were crossed to either 129S6/SvEvTac or CAST/EiJ and the F1 progeny were analyzed by slit-lamp biomicroscopy and optical coherence tomography. We also measured IOPs and compared tissue sections of eyes and optic nerves. RESULTS We found that the CAST/EiJ inbred strain has a relatively uniform and profound suppression on the effects of Col4a1 mutation and that mutant CASTB6F1 mice were generally only very mildly affected. In contrast, mutant 129B6F1 mice had more variable and severe ASD and IOP dysregulation that were associated with glaucomatous signs including lost or damaged retinal ganglion cell axons and excavation of the optic nerve head. CONCLUSIONS Ocular defects in Col4a1 mutant mice model ASD and glaucoma that are observed in a subset of patients with COL4A1 mutations. We demonstrate that different inbred strains of mice give graded severities of ASD and we detected elevated IOP and glaucomatous damage in 129B6F1, but not CASTB6F1 mice that carried a Col4a1 mutation. These data demonstrate that genetic context differences are one factor that may contribute to the variable penetrance and severity of ASD and glaucoma in patients with COL4A1 mutations.
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Affiliation(s)
- Mao Mao
- Departments of Ophthalmology and Anatomy Institute for Human Genetics, UCSF School of Medicine, San Francisco, California, United States
| | | | - Marcel V Alavi
- Departments of Ophthalmology and Anatomy Institute for Human Genetics, UCSF School of Medicine, San Francisco, California, United States
| | - Jeffrey K Marchant
- The Jackson Laboratory, Bar Harbor, Maine, United States 3Department of Anatomy and Cell Biology, Department of Ophthalmology, Tufts University School of Medicine, Boston, Massachusetts, United States
| | - Mihai Cosma
- The Jackson Laboratory, Bar Harbor, Maine, United States
| | - Richard T Libby
- Flaum Eye Institute, Department of Biomedical Genetics, The Center for Visual Sciences, University of Rochester Medical Center, Rochester, New York, United States
| | - Simon W M John
- The Jackson Laboratory, Bar Harbor, Maine, United States 3Department of Anatomy and Cell Biology, Department of Ophthalmology, Tufts University School of Medicine, Boston, Massachusetts, United States 5The Howard Hughes Medical Institute, Bar Harbor, Main
| | - Douglas B Gould
- Departments of Ophthalmology and Anatomy Institute for Human Genetics, UCSF School of Medicine, San Francisco, California, United States
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García-Muñoz A, Rodríguez MA, Licéaga-Escalera C, Licéaga-Reyes R, Carreón-Burciaga RG, González-González R, Bologna-Molina R. Expression of the transcription factor PITX2 in ameloblastic carcinoma. Arch Oral Biol 2015; 60:799-803. [PMID: 25791324 DOI: 10.1016/j.archoralbio.2015.02.017] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2014] [Revised: 10/06/2014] [Accepted: 02/20/2015] [Indexed: 02/07/2023]
Abstract
Ameloblastic carcinoma is a rare odontogenic tumour that combines the histological features of ameloblastoma with cytological atypia. Until 2005, the incidence of ameloblastic carcinoma was unknown, and since then, fewer than 60 cases have been reported. These tumours may originate from pre-existing tumours or cysts, or they arise de novo from the activation or transformation of embryological cells. PITX2 is a transcription factor that is a product and regulator of the WNT cell signalling pathway, which has been involved in development of several tumours. To analyse whether PITX2 could be involved in the biological behaviour of ameloblastic carcinoma, we analysed the expression of this transcription factor in a sample of this tumour and nine benign ameloblastomas to compare. The results of Western blotting and RT-PCR analyses were positive, and considering the hundreds of genes that PITX2 regulates, we believe that its expression could be intimately linked to the behaviour of ameloblastic carcinoma and possibly other odontogenic lesions.
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Affiliation(s)
- Alejandro García-Muñoz
- School of Dentistry, Universidad Juárez del Estado de Durango, Durango, Mexico; Department of Infectomics and Molecular Pathogenesis, CINVESTAV-IPN, México, D.F., Mexico
| | - Mario A Rodríguez
- Department of Infectomics and Molecular Pathogenesis, CINVESTAV-IPN, México, D.F., Mexico
| | | | | | | | | | - Ronell Bologna-Molina
- School of Dentistry, Universidad Juárez del Estado de Durango, Durango, Mexico; Molecular Pathology, School of Dentistry, Universidad de la República (UDELAR), Montevideo, Uruguay.
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Torrado M, Franco D, Hernández-Torres F, Crespo-Leiro MG, Iglesias-Gil C, Castro-Beiras A, Mikhailov AT. Pitx2c is reactivated in the failing myocardium and stimulates myf5 expression in cultured cardiomyocytes. PLoS One 2014; 9:e90561. [PMID: 24595098 PMCID: PMC3942452 DOI: 10.1371/journal.pone.0090561] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2013] [Accepted: 02/01/2014] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND Pitx2 (paired-like homeodomain 2 transcription factor) is crucial for heart development, but its role in heart failure (HF) remains uncertain. The present study lays the groundwork implicating Pitx2 signalling in different modalities of HF. METHODOLOGY/PRINCIPAL FINDINGS A variety of molecular, cell-based, biochemical, and immunochemical assays were used to evaluate: (1) Pitx2c expression in the porcine model of diastolic HF (DHF) and in patients with systolic HF (SHF) due to dilated and ischemic cardiomyopathy, and (2) molecular consequences of Pitx2c expression manipulation in cardiomyocytes in vitro. In pigs, the expression of Pitx2c, physiologically downregulated in the postnatal heart, is significantly re-activated in left ventricular (LV) failing myocardium which, in turn, is associated with increased expression of a restrictive set of Pitx2 target genes. Among these, Myf5 was identified as the top upregulated gene. In vitro, forced expression of Pitx2c in cardiomyocytes, but not in skeletal myoblasts, activates Myf5 in dose-dependent manner. In addition, we demonstrate that the level of Pitx2c is upregulated in the LV-myocardium of SHF patients. CONCLUSIONS/SIGNIFICANCE The results provide previously unrecognized evidence that Pitx2c is similarly reactivated in postnatal/adult heart at distinct HF phenotypes and suggest that Pitx2c is involved, directly or indirectly, in the regulation of Myf5 expression in cardiomyocytes.
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Affiliation(s)
- Mario Torrado
- Institute of Health Sciences, University of La Coruña, La Coruña, Spain
| | - Diego Franco
- Department of Experimental Biology, University of Jaen, Jaen, Spain
| | | | | | | | - Alfonso Castro-Beiras
- Institute of Health Sciences, University of La Coruña, La Coruña, Spain
- University Hospital Center of La Coruña, La Coruña, Spain
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Liu Y, Huang Y, Fan J, Zhu GZ. PITX2 associates with PTIP-containing histone H3 lysine 4 methyltransferase complex. Biochem Biophys Res Commun 2014; 444:634-7. [PMID: 24486544 PMCID: PMC3963365 DOI: 10.1016/j.bbrc.2014.01.143] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2014] [Accepted: 01/24/2014] [Indexed: 11/30/2022]
Abstract
Pituitary homeobox 2 (PITX2), a Paired-like homeodomain transcription factor and a downstream effector of Wnt/β-catenin signaling, plays substantial roles in embryonic development and human disorders. The mechanism of its functions, however, is not fully understood. In this study, we demonstrated that PITX2 associated with histone H3 lysine 4 (H3K4) methyltransferase (HKMT) mixed-lineage leukemia 4 (MLL4/KMT2D), Pax transactivation domain-interacting protein (PTIP), and other H3K4·HKMT core subunits. This association of PITX2 with H3K4·HKMT complex was dependent on PITX2's homeodomain. Consistently, the PITX2 protein complex was shown to possess H3K4·HKMT activity. Furthermore, the chromatin immunoprecipitation result revealed co-occupancy of PITX2 and PTIP on the promoter of the PITX2's transcriptional target. Taken together, our data provide new mechanistic perspectives on PITX2's functions and its related biological processes.
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Affiliation(s)
- Yan Liu
- Department of Ophthalmology, Huashan Hospital Affiliated to Fudan University, Shanghai 200040, People's Republic of China
| | - Yue Huang
- Department of Biological Sciences, Marshall University, Huntington, WV, USA
| | - Jun Fan
- Department of Biochemistry and Microbiology, Genomic Core Facility, School of Medicine, Marshall University, Huntington, WV, USA
| | - Guo-Zhang Zhu
- Department of Biological Sciences, Marshall University, Huntington, WV, USA.
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8
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Zhao H, Wu X, Cai H, Pan C, Lei C, Chen H, Lan X. Genetic variants and effects on milk traits of the caprine paired-like homeodomain transcription factor 2 (PITX2) gene in dairy goats. Gene 2013; 532:203-10. [DOI: 10.1016/j.gene.2013.09.062] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2013] [Revised: 09/01/2013] [Accepted: 09/17/2013] [Indexed: 12/20/2022]
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9
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Liu Y, Huang Y, Zhu GZ. Cyclin A1 is a transcriptional target of PITX2 and overexpressed in papillary thyroid carcinoma. Mol Cell Biochem 2013; 384:221-7. [PMID: 24002705 DOI: 10.1007/s11010-013-1801-9] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2013] [Accepted: 08/23/2013] [Indexed: 10/26/2022]
Abstract
Physiological expression of cyclin A1, a unique cell cycle regulator essential for spermatogenesis, is predominantly restricted in male germ cells. Outstandingly, previous studies have also demonstrated the abnormal expression of cyclin A1 in various human tumors. How male germ cell-specific cyclin A1 is transcriptionally activated in tumor cells, however, is elusive. To begin to understand the molecular mechanisms governing the ectopic expression of cyclin A1, we searched for transcription factors and cis-regulatory DNA elements. We found that overexpression of PITX2, a paired-like homeodomain transcription factor and a downstream effector of Wnt/β-catenin signaling, resulted in upregulation of cyclin A1 in HEK293 cells and TPC-1 thyroid cancer cells. On the other hand, PITX2 knockdown in TPC-1 cells caused reduced cyclin A1. Promoter reporter assays with a series of deletion constructs determined that the DNA element from -102 to -96 bp of the cyclin A1 promoter is responsible for PITX2-induced gene expression. The result of chromatin immunoprecipitation revealed the occupancy of PITX2 on the cyclin A1 promoter. Taken together, these findings demonstrate that cyclin A1 is a transcriptional target of PITX2. Consistently, our immunohistochemistry result showed up-regulation of cyclin A1 in human papillary thyroid carcinoma, where overexpressed PITX2 has been endorsed in our recent report. Thus, our study provides new evidence on the regulation of cyclin A1 gene expression and offers a PITX2-cycin A1 pathway for cell cycle regulation.
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Affiliation(s)
- Yan Liu
- Department of Ophthalmology, Huashan Hospital Affiliated to Fudan University, 12 Middle Wulumuqi Road, Shanghai, 200040, People's Republic of China
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Abstract
PTEN (phosphatase and tensin homologue deleted on chromosome ten) plays critical roles in multiple cellular processes, including cell proliferation, survival, migration and transformation. A role of PTEN in mammalian spermatogenesis, however, has not been explored. To address this question, we generated a mouse model with PTEN conditional knockout in postnatal male germ cells. We found that spermatogenesis was normal in PTEN-deleted male germ cells. PTEN conditional mutant males produced sperm and sired offspring as competently as wild-type littermates. Moreover, our biochemical analysis also indicated that the Akt (acutely transforming retrovirus AKT8 in rodent T cell lymphoma) signalling pathway was not affected in mutant testis. Taken together, these findings demonstrate that PTEN is dispensable in mouse spermatogenesis.
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Doerdelmann T, Kojetin DJ, Baird-Titus JM, Solt LA, Burris TP, Rance M. Structural and biophysical insights into the ligand-free Pitx2 homeodomain and a ring dermoid of the cornea inducing homeodomain mutant. Biochemistry 2012; 51:665-76. [PMID: 22224469 PMCID: PMC3264736 DOI: 10.1021/bi201639x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The homeodomain-containing transcription factor Pitx2 (pituitary homeobox protein 2) is present in many developing embryonic tissues, including the heart. Its homeodomain is responsible for the recognition and binding to target DNA sequences and thus constitutes a major functional unit in the Pitx2 protein. Nuclear magnetic resonance techniques were employed to determine the solution structure of the native Pitx2 homeodomain and a R24H mutant that causes autosomal dominantly inherited ring dermoid of the cornea syndrome. The structures reveal that both isoforms possess the canonical homeodomain fold. However, the R24H mutation results in a 2-fold increase in DNA binding affinity and a 5 °C decrease in thermal stability, while changing the dynamic environment of the homeodomain only locally. When introduced into full-length Pitx2c, the mutation results in an only 25% loss of transactivation activity. Our data correlate well with clinical observations suggesting a milder deficiency for the R24H mutation compared to those of other Pitx2 homeodomain mutations.
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Affiliation(s)
- Thomas Doerdelmann
- University of Cincinnati, Department of Molecular Genetics, Biochemistry and Microbiology, 231 Albert Sabin Way, Cincinnati, OH 45267, USA
| | - Douglas J. Kojetin
- University of Cincinnati, Department of Molecular Genetics, Biochemistry and Microbiology, 231 Albert Sabin Way, Cincinnati, OH 45267, USA
- The Scripps Research Institute, Scripps Florida, Department of Molecular Therapeutics, 130 Scripps Way, Jupiter, FL 33458, USA
| | - Jamie M. Baird-Titus
- College of Mount St. Joseph, Department of Chemistry, 5701 Delhi Road, Cincinnati, OH 45233, USA
| | - Laura A. Solt
- The Scripps Research Institute, Scripps Florida, Department of Molecular Therapeutics, 130 Scripps Way, Jupiter, FL 33458, USA
| | - Thomas P. Burris
- The Scripps Research Institute, Scripps Florida, Department of Molecular Therapeutics, 130 Scripps Way, Jupiter, FL 33458, USA
| | - Mark Rance
- University of Cincinnati, Department of Molecular Genetics, Biochemistry and Microbiology, 231 Albert Sabin Way, Cincinnati, OH 45267, USA
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Strungaru MH, Footz T, Liu Y, Berry FB, Belleau P, Semina EV, Raymond V, Walter MA. PITX2 is involved in stress response in cultured human trabecular meshwork cells through regulation of SLC13A3. Invest Ophthalmol Vis Sci 2011; 52:7625-33. [PMID: 21873665 PMCID: PMC3183983 DOI: 10.1167/iovs.10-6967] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2010] [Revised: 05/17/2011] [Accepted: 06/04/2011] [Indexed: 10/17/2022] Open
Abstract
PURPOSE Mutations of the PITX2 gene cause Axenfeld-Rieger syndrome (ARS) and glaucoma. In this study, the authors investigated genes directly regulated by the PITX2 transcription factor to gain insight into the mechanisms underlying these disorders. METHODS RNA from nonpigmented ciliary epithelium cells transfected with hormone-inducible PITX2 and activated by mifepristone was subjected to microarray analyses. Data were analyzed using dCHIP algorithms to detect significant differences in expression. Genes with significantly altered expression in multiple microarray experiments in the presence of activated PITX2 were subjected to in silico and biochemical analyses to validate them as direct regulatory targets. One target gene was further characterized by studying the effect of its knockdown in a cell model of oxidative stress, and its expression in zebrafish embryos was analyzed by in situ hybridization. RESULTS Solute carrier family 13 sodium-dependent dicarboxylate transporter member 3 (SLC13A3) was identified as 1 of 47 potential PITX2 target genes in ocular cells. PITX2 directly regulates SLC13A3 expression, as demonstrated by luciferase reporter and chromatin immunoprecipitation assays. Reduction of PITX2 or SLC13A3 levels by small interfering RNA (siRNA)-mediated knockdown augmented the death of transformed human trabecular meshwork cells exposed to hydrogen peroxide. Zebrafish slc13a3 is expressed in anterior ocular regions in a pattern similar to that of pitx2. CONCLUSIONS The results indicate that SLC13A3 is a direct downstream target of PITX2 transcriptional regulation and that levels of PITX2 and SLC13A3 modulate responses to oxidative stress in ocular cells.
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Affiliation(s)
| | - Tim Footz
- From the Departments of Medical Genetics and
| | - Yi Liu
- Department of Pediatrics and Children's Research Institute, Medical College of Wisconsin and Children's Hospital of Wisconsin, Milwaukee, Wisconsin
| | - Fred B. Berry
- From the Departments of Medical Genetics and
- Surgery, University of Alberta, Edmonton, Alberta, Canada
| | - Pascal Belleau
- Department of Molecular Medicine, Université Laval, Québec City, Quebec, Canada; and
| | - Elena V. Semina
- Department of Pediatrics and Children's Research Institute, Medical College of Wisconsin and Children's Hospital of Wisconsin, Milwaukee, Wisconsin
- Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - Vincent Raymond
- Department of Molecular Medicine, Université Laval, Québec City, Quebec, Canada; and
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Paylakhi SH, Fan JB, Mehrabian M, Sadeghizadeh M, Yazdani S, Katanforoush A, Kanavi MR, Ronaghi M, Elahi E. Effect of PITX2 knockdown on transcriptome of primary human trabecular meshwork cell cultures. Mol Vis 2011; 17:1209-21. [PMID: 21617755 PMCID: PMC3102028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2011] [Accepted: 04/25/2011] [Indexed: 11/23/2022] Open
Abstract
PURPOSE To identify genes whose expressions in primary human trabecular meshwork (TM) cell cultures are affected by the transcription factor pituitary homeobox 2 (PITX2) and to identify genes that may have roles in glaucoma. Known glaucoma causing genes account for disease in a small fraction of patients, and we aimed at identification of other genes that may have subtle and accumulative effects not easily identifiable by a genetic approach. METHODS Expression profiles derived using microarrays were compared between TM control cells and cells treated with PITX2 siRNAs using three protocols so as to minimize false positive and negative results. The first protocol was based on the commonly used B statistic. The second and third protocols were based on fold change in expression. The second protocol used a threshold of at least 2 fold change in expression, whereas the third protocol used ranking in fold change without setting a threshold. The likelihood of a selected gene being a true positive was considered to correlate with the number of protocols by which it was selected. By considering all genes that were selected by at least one protocol, the likelihood of false negatives was expected to decrease. Effects on a subset of selected genes were verified by real time PCR, western blots, and immunocytochemistry. Effects on ALDH1A1, were further pursued because its protein product, aldehyde dehydrogenase 1 family, member A1, has roles in oxidative stress and because oxidative stress is known to be relevant to the etiology of glaucoma. RESULTS The expression level of 41 genes was assessed by to be possibly affected by PITX2 knockdown. Twenty one genes were down-regulated and twenty were upregulated. The expression of five genes was assessed to be altered by all three analysis protocols. The five genes were DIRAS3 (DIRAS family, GTP-binding RAS-like 3), CXCL6 (chemokine (C-X-C motif) ligand 6), SAMD5 (sterile alpha motif domain containing 5), CBFB (core-binding factor, beta subunit), and MEIS2 (meis homeobox 2). Real time PCR experiments verified results on a subset of genes tested. Notably, the results were also confirmed in two independent TMs. Effects on CXCL6 and ALDH1A1 were also confirmed by western blots, and effects on ALDH1A1 were further shown by immunocytochemistry. Data consistent with PITX2 involvement in ALDH1A1 mediated response to oxidative stress were presented. CONCLUSIONS Bioinformatics tools revealed that the genes identified affect functions and pathways relevant to glaucoma. Involvement of PITX2 in expression of some of the genes and in some of the pathways is being reported here for the first time. As many of the genes identified have not been studied vis-à-vis glaucoma, we feel they introduce new candidates for understanding this devastating disease.
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Affiliation(s)
- Seyed Hassan Paylakhi
- Department of Genetics, Faculty of Biological Sciences, Tarbiat Modares University, Tehran, Iran
| | | | | | - Majid Sadeghizadeh
- Department of Genetics, Faculty of Biological Sciences, Tarbiat Modares University, Tehran, Iran
| | - Shahin Yazdani
- Ophthalmic Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Ali Katanforoush
- Department of Computer Science, Faculty of Mathematics, Shahid Beheshti University G.C., Tehran, Iran
| | - Mozhgan Rezaei Kanavi
- Ophthalmic Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
- Central Eye Bank of Iran, Tehran, Iran
| | | | - Elahe Elahi
- Department of Biotechnology, University of Tehran, Tehran, Iran
- Department of Biology, University College of Science, University of Tehran, Tehran, Iran
- Center of Excellence in Biomathematics, School of Mathematics, Statistics and Computer Science, College of Science, University of Tehran, Tehran, Iran
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Kausel G, Vera T, Valenzuela G, Lopez M, Romero A, Muller M, Figueroa J. At least two expressed genes for transcription factors Pitx2 and Rpx are present in common carp and are upregulated during winter acclimatization. Gen Comp Endocrinol 2010; 169:250-7. [PMID: 20850444 DOI: 10.1016/j.ygcen.2010.09.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/16/2010] [Revised: 08/09/2010] [Accepted: 09/09/2010] [Indexed: 10/19/2022]
Abstract
The mechanisms of seasonal acclimatization in eurythermal fish such as common carp are not fully understood. Here, we concentrate on the regulation of pituitary factors, as this organ was shown to be highly affected by seasonal changes. We cloned and sequenced two different cDNAs for each of the transcription factors Pitx2 and Rpx, known to play a role in pituitary development. We show that these genes are conserved throughout evolution, to different degrees depending on the specific domain considered. Finally, we show that the cDNAs for both factors are clearly up-regulated during the winter season, in sharp contrast to other regulators such as Pit1 or pituitary hormone genes such as prolactin (prl) and growth hormone (gh). Our results suggest that increased expression of Pitx2 and Rpx contributes to seasonal adaptation of common carp to winter conditions.
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Affiliation(s)
- G Kausel
- Instituto de Bioquímica, Facultad de Ciencias, Universidad Austral de Chile, Valdivia, Chile.
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Napieralski R, Brünner N, Mengele K, Schmitt M. Emerging biomarkers in breast cancer care. Biomark Med 2010; 4:505-22. [DOI: 10.2217/bmm.10.73] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Currently, decision-making for breast cancer treatment in the clinical setting is mainly based on clinical data, histomorphological features of the tumor tissue and a few cancer biomarkers such as steroid hormone receptor status (estrogen and progesterone receptors) and oncoprotein HER2 status. Although various therapeutic options were introduced into the clinic in recent decades, with the objective of improving surgery, radiotherapy, biochemotherapy and chemotherapy, varying response of individual patients to certain types of therapy and therapy resistance is still a challenge in breast cancer care. Therefore, since breast cancer treatment should be based on individual features of the patient and her tumor, tailored therapy should be an option by integrating cancer biomarkers to define patients at risk and to reliably predict their course of the disease and/or response to cancer therapy. Recently, candidate-marker approaches and genome-wide transcriptomic and epigenetic screening of different breast cancer tissues and bodily fluids resulted in new promising biomarker panels, allowing breast cancer prognosis, prediction of therapy response and monitoring of therapy efficacy. These biomarkers are now subject of validation in prospective clinical trials.
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Affiliation(s)
- Rudolf Napieralski
- Clinical Research Unit, Department of Obstetrics & Gynecology, Klinikum rechts der Isar, Technische Universitaet Muenchen, Germany
| | - Nils Brünner
- University of Copenhagen, Faculty of Life Sciences, Department of Veterinary Disease Biology, Ridebanevej 9, DK-1870 Frederiksberg C, Denmark
| | - Karin Mengele
- Clinical Research Unit, Department of Obstetrics & Gynecology, Klinikum rechts der Isar, Technische Universitaet Muenchen, Germany
| | - Manfred Schmitt
- Clinical Research Unit, Department of Obstetrics & Gynecology, Ismaninger Strasse 22, Klinikum rechts der Isar, Technische Universitaet Muenchen, D-81675 Munich, Germany
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