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Bhattacharyya S, Bhakta M, Munshi NV. Phenotypically silent Cre recombination within the postnatal ventricular conduction system. PLoS One 2017; 12:e0174517. [PMID: 28358866 PMCID: PMC5373586 DOI: 10.1371/journal.pone.0174517] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Accepted: 03/10/2017] [Indexed: 01/30/2023] Open
Abstract
The cardiac conduction system (CCS) is composed of specialized cardiomyocytes that initiate and maintain cardiac rhythm. Any perturbation to the normal sequence of electrical events within the heart can result in cardiac arrhythmias. To understand how cardiac rhythm is established at the molecular level, several genetically modified mouse lines expressing Cre recombinase within specific CCS compartments have been created. In general, Cre driver lines have been generated either by homologous recombination of Cre into an endogenous locus or Cre expression driven by a randomly inserted transgene. However, haploinsufficiency of the endogenous gene compromises the former approach, while position effects negatively impact the latter. To address these limitations, we generated a Cre driver line for the ventricular conduction system (VCS) that preserves endogenous gene expression by targeting the Contactin2 (Cntn2) 3’ untranslated region (3’UTR). Here we show that Cntn23’UTR-IRES-Cre-EGFP/+ mice recombine floxed alleles within the VCS and that Cre expression faithfully recapitulates the spatial distribution of Cntn2 within the heart. We further demonstrate that Cre expression initiates after birth with preservation of native Cntn2 protein. Finally, we show that Cntn23’UTR-IRES-Cre-EGFP/+ mice maintain normal cardiac mechanical and electrical function. Taken together, our results establish a novel VCS-specific Cre driver line without the adverse consequences of haploinsufficiency or position effects. We expect that our new mouse line will add to the accumulating toolkit of CCS-specific mouse reagents and aid characterization of the cell-autonomous molecular circuitry that drives VCS maintenance and function.
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Affiliation(s)
- Samadrita Bhattacharyya
- Department of Internal Medicine (Cardiology Division), UT Southwestern Medical Center, Dallas, TX, United States of America
| | - Minoti Bhakta
- Department of Internal Medicine (Cardiology Division), UT Southwestern Medical Center, Dallas, TX, United States of America
| | - Nikhil Vilas Munshi
- Department of Internal Medicine (Cardiology Division), UT Southwestern Medical Center, Dallas, TX, United States of America
- Department of Molecular Biology, UT Southwestern Medical Center, Dallas, TX, United States of America
- McDermott Center for Human Growth and Development, UT Southwestern Medical Center, Dallas, TX, United States of America
- Center for Regenerative Science and Medicine, UT Southwestern Medical Center, Dallas, TX, United States of America
- * E-mail:
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Alvarez I, Collado JA, Colobran R, Carrascal M, Ciudad MT, Canals F, James EA, Kwok WW, Gärtner M, Kyewski B, Pujol-Borrell R, Jaraquemada D. Central T cell tolerance: Identification of tissue-restricted autoantigens in the thymus HLA-DR peptidome. J Autoimmun 2015; 60:12-9. [PMID: 25911201 DOI: 10.1016/j.jaut.2015.03.004] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2015] [Revised: 03/12/2015] [Accepted: 03/18/2015] [Indexed: 11/22/2022]
Abstract
Promiscuous gene expression (pGE) of tissue-restricted self-antigens (TRA) in medullary thymic epithelial cells (mTECs) is in part driven by the Autoimmune Regulator gene (AIRE) and essential for self-tolerance. The link between AIRE functional mutations and multi-organ autoimmunity in human and mouse supports the role of pGE. Deep sequencing of the transcriptome revealed that mouse mTECs potentially transcribe an unprecedented range of >90% of all genes. Yet, it remains unclear to which extent these low-level transcripts are actually translated into proteins, processed and presented by thymic APCs to induce tolerance. To address this, we analyzed the HLA-DR-associated thymus peptidome. Within a large panel of peptides from abundant proteins, two TRA peptides were identified: prostate-specific semenogelin-1 (an autoantigen in autoimmune chronic prostatitis/chronic pelvic pain syndrome) and central nervous system-specific contactin-2 (an autoantigen in multiple sclerosis). Thymus expression of both genes was restricted to mTECs. SEMG1 expression was confined to mature HLA-DR(hi) mTECs of male and female donors and was AIRE-dependent, whereas CNTN2 was apparently AIRE-independent and was expressed by both populations of mTECs. Our findings establish a link between pGE, MHC-II peptide presentation and autoimmunity for bona fide human TRAs.
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Affiliation(s)
- Iñaki Alvarez
- Immunology Unit, Institut de Biotecnologia i Biomedicina, Universitat Autònoma de Barcelona, 08193 Cerdanyola del Vallès, Barcelona, Spain; Dept of Cell Biology, Physiology and Immunology, Universitat Autònoma de Barcelona, 08193 Cerdanyola del Vallès, Barcelona, Spain
| | - Javier A Collado
- Immunology Unit, Institut de Biotecnologia i Biomedicina, Universitat Autònoma de Barcelona, 08193 Cerdanyola del Vallès, Barcelona, Spain; Dept of Cell Biology, Physiology and Immunology, Universitat Autònoma de Barcelona, 08193 Cerdanyola del Vallès, Barcelona, Spain
| | - Roger Colobran
- Dept of Cell Biology, Physiology and Immunology, Universitat Autònoma de Barcelona, 08193 Cerdanyola del Vallès, Barcelona, Spain; Immunology Division, Hospital Universitari Vall d'Hebron (HUVH), Vall d'Hebron Institut de Recerca (VHIR), Passeig Vall d'Hebron 119-129, 08023 Barcelona, Spain
| | - Montserrat Carrascal
- CSIC/UAB Proteomics Laboratory, IIBB-CSIC, IDIBAPS, Facultat de Medicina, Universitat Autònoma de Barcelona, 08193 Cerdanyola del Vallès, Barcelona, Spain
| | - M Teresa Ciudad
- Immunology Unit, Institut de Biotecnologia i Biomedicina, Universitat Autònoma de Barcelona, 08193 Cerdanyola del Vallès, Barcelona, Spain; Dept of Cell Biology, Physiology and Immunology, Universitat Autònoma de Barcelona, 08193 Cerdanyola del Vallès, Barcelona, Spain
| | - Françesc Canals
- Proteomics Laboratory, Medical Oncology Research Program, Vall d'Hebron Institut de Recerca, Barcelona, Spain
| | - Eddie A James
- Benaroya Research Institute at Virginia Mason, Seattle, WA, USA
| | - William W Kwok
- Benaroya Research Institute at Virginia Mason, Seattle, WA, USA
| | - Martina Gärtner
- Division of Developmental Immunology, Tumor Immunology Program, German Cancer Research Center, 69120 Heidelberg, Germany
| | - Bruno Kyewski
- Division of Developmental Immunology, Tumor Immunology Program, German Cancer Research Center, 69120 Heidelberg, Germany
| | - Ricardo Pujol-Borrell
- Dept of Cell Biology, Physiology and Immunology, Universitat Autònoma de Barcelona, 08193 Cerdanyola del Vallès, Barcelona, Spain; Immunology Division, Hospital Universitari Vall d'Hebron (HUVH), Vall d'Hebron Institut de Recerca (VHIR), Passeig Vall d'Hebron 119-129, 08023 Barcelona, Spain
| | - Dolores Jaraquemada
- Immunology Unit, Institut de Biotecnologia i Biomedicina, Universitat Autònoma de Barcelona, 08193 Cerdanyola del Vallès, Barcelona, Spain; Dept of Cell Biology, Physiology and Immunology, Universitat Autònoma de Barcelona, 08193 Cerdanyola del Vallès, Barcelona, Spain.
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