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Pedroza AJ, Dalal AR, Shad R, Yokoyama N, Nakamura K, Cheng P, Wirka RC, Mitchel O, Baiocchi M, Hiesinger W, Quertermous T, Fischbein MP. Embryologic Origin Influences Smooth Muscle Cell Phenotypic Modulation Signatures in Murine Marfan Syndrome Aortic Aneurysm. Arterioscler Thromb Vasc Biol 2022; 42:1154-1168. [PMID: 35861960 PMCID: PMC9420801 DOI: 10.1161/atvbaha.122.317381] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Aortic root smooth muscle cells (SMC) develop from both the second heart field (SHF) and neural crest. Disparate responses to disease-causing Fbn1 variants by these lineages are proposed to promote focal aortic root aneurysm formation in Marfan syndrome (MFS), but lineage-stratified SMC analysis in vivo is lacking. METHODS We generated SHF lineage-traced MFS mice and performed integrated multiomic (single-cell RNA and assay for transposase-accessible chromatin sequencing) analysis stratified by embryological origin. SMC subtypes were spatially identified via RNA in situ hybridization. Response to TWIST1 overexpression was determined via lentiviral transduction in human aortic SMCs. RESULTS Lineage stratification enabled nuanced characterization of aortic root cells. We identified heightened SHF-derived SMC heterogeneity including a subset of Tnnt2 (cardiac troponin T)-expressing cells distinguished by altered proteoglycan expression. MFS aneurysm-associated SMC phenotypic modulation was identified in both SHF-traced and nontraced (neural crest-derived) SMCs; however, transcriptomic responses were distinct between lineages. SHF-derived modulated SMCs overexpressed collagen synthetic genes and small leucine-rich proteoglycans while nontraced SMCs activated chondrogenic genes. These modulated SMCs clustered focally in the aneurysmal aortic root at the region of SHF/neural crest lineage overlap. Integrated RNA-assay for transposase-accessible chromatin analysis identified enriched Twist1 and Smad2/3/4 complex binding motifs in SHF-derived modulated SMCs. TWIST1 overexpression promoted collagen and SLRP gene expression in vitro, suggesting TWIST1 may drive SHF-enriched collagen synthesis in MFS aneurysm. CONCLUSIONS SMCs derived from both SHF and neural crest lineages undergo phenotypic modulation in MFS aneurysm but are defined by subtly distinct transcriptional responses. Enhanced TWIST1 transcription factor activity may contribute to enriched collagen synthetic pathways SHF-derived SMCs in MFS.
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Affiliation(s)
- Albert J. Pedroza
- Department of Cardiothoracic Surgery, Stanford University School of Medicine. Stanford CA, USA
| | - Alex R. Dalal
- Department of Cardiothoracic Surgery, Stanford University School of Medicine. Stanford CA, USA
| | - Rohan Shad
- Department of Cardiothoracic Surgery, Stanford University School of Medicine. Stanford CA, USA
| | - Nobu Yokoyama
- Department of Cardiothoracic Surgery, Stanford University School of Medicine. Stanford CA, USA
| | - Ken Nakamura
- Department of Cardiothoracic Surgery, Stanford University School of Medicine. Stanford CA, USA
| | - Paul Cheng
- Division of Cardiovascular Medicine, Stanford University School of Medicine. Stanford CA, USA
| | - Robert C. Wirka
- Division of Cardiology, UNC School of Medicine, Chapel Hill NC, USA
| | | | - Michael Baiocchi
- Department of Epidemiology and Population Health, Stanford Unviersity School of Medicine. Stanford CA, USA
| | - William Hiesinger
- Department of Cardiothoracic Surgery, Stanford University School of Medicine. Stanford CA, USA
| | - Thomas Quertermous
- Division of Cardiovascular Medicine, Stanford University School of Medicine. Stanford CA, USA
| | - Michael P. Fischbein
- Department of Cardiothoracic Surgery, Stanford University School of Medicine. Stanford CA, USA
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Zakariyah AF, Rajgara RF, Horner E, Cattin ME, Blais A, Skerjanc IS, Burgon PG. In Vitro Modeling of Congenital Heart Defects Associated with an NKX2-5 Mutation Revealed a Dysregulation in BMP/Notch-Mediated Signaling. Stem Cells 2018; 36:514-526. [DOI: 10.1002/stem.2766] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2017] [Revised: 12/04/2017] [Accepted: 12/09/2017] [Indexed: 02/02/2023]
Affiliation(s)
- Abeer F. Zakariyah
- Department of Biochemistry, Microbiology, and Immunology, University of Ottawa; Ottawa Ontario Canada
| | - Rashida F. Rajgara
- Department of Biochemistry, Microbiology, and Immunology, University of Ottawa; Ottawa Ontario Canada
| | - Ellias Horner
- Department of Biochemistry, Microbiology, and Immunology, University of Ottawa; Ottawa Ontario Canada
- Ottawa Institute of Systems Biology, Department of Biochemistry, Microbiology and Immunology, Faculty of Medicine, University of Ottawa; Ottawa Ontario Canada
- Center for Neuromuscular Disease, University of Ottawa; Ottawa Ontario Canada
| | | | - Alexandre Blais
- Department of Biochemistry, Microbiology, and Immunology, University of Ottawa; Ottawa Ontario Canada
- Ottawa Institute of Systems Biology, Department of Biochemistry, Microbiology and Immunology, Faculty of Medicine, University of Ottawa; Ottawa Ontario Canada
- Center for Neuromuscular Disease, University of Ottawa; Ottawa Ontario Canada
| | - Ilona S. Skerjanc
- Department of Biochemistry, Microbiology, and Immunology, University of Ottawa; Ottawa Ontario Canada
| | - Patrick G. Burgon
- Center for Neuromuscular Disease, University of Ottawa; Ottawa Ontario Canada
- Department of Medicine (Division of Cardiology); University of Ottawa; Ottawa Ontario Canada
- University of Ottawa Heart Institute; Ottawa Ontario Canada
- Department of Cellular and Molecular Medicine, University of Ottawa; Ottawa Ontario Canada
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3
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Goodnough LH, Dinuoscio GJ, Atit RP. Twist1 contributes to cranial bone initiation and dermal condensation by maintaining Wnt signaling responsiveness. Dev Dyn 2015; 245:144-56. [PMID: 26677825 DOI: 10.1002/dvdy.24367] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2015] [Revised: 10/29/2015] [Accepted: 10/30/2015] [Indexed: 11/09/2022] Open
Abstract
BACKGROUND Specification of cranial bone and dermal fibroblast progenitors in the supraorbital arch mesenchyme is Wnt/β-catenin signaling-dependent. The mechanism underlying how these cells interpret instructive signaling cues and differentiate into these two lineages is unclear. Twist1 is a target of the Wnt/β-catenin signaling pathway and is expressed in cranial bone and dermal lineages. RESULTS Here, we show that onset of Twist1 expression in the mouse cranial mesenchyme is dependent on ectodermal Wnts and mesenchymal β-catenin activity. Conditional deletion of Twist1 in the supraorbital arch mesenchyme leads to cranial bone agenesis and hypoplastic dermis, as well as craniofacial malformation of eyes and palate. Twist1 is preferentially required for cranial bone lineage commitment by maintaining Wnt responsiveness. In the conditional absence of Twist1, the cranial dermis fails to condense and expand apically leading to extensive cranial dermal hypoplasia with few and undifferentiated hair follicles. CONCLUSIONS Thus, Twist1, a target of canonical Wnt/β-catenin signaling, also functions to maintain Wnt responsiveness and is a key effector for cranial bone fate selection and dermal condensation.
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Affiliation(s)
- L Henry Goodnough
- Department of Pathology, Case Western Reserve University, Cleveland, Ohio
| | - Gregg J Dinuoscio
- Department of Biology, Case Western Reserve University, Cleveland, Ohio
| | - Radhika P Atit
- Department of Biology, Case Western Reserve University, Cleveland, Ohio.,Department of Genetics and Genome Sciences, Case Western Reserve University, Cleveland, Ohio.,Department of Dermatology, Case Western Reserve University, Cleveland, Ohio
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Garside VC, Cullum R, Alder O, Lu DY, Vander Werff R, Bilenky M, Zhao Y, Jones SJM, Marra MA, Underhill TM, Hoodless PA. SOX9 modulates the expression of key transcription factors required for heart valve development. Development 2015; 142:4340-50. [PMID: 26525672 DOI: 10.1242/dev.125252] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2015] [Accepted: 10/28/2015] [Indexed: 01/10/2023]
Abstract
Heart valve formation initiates when endothelial cells of the heart transform into mesenchyme and populate the cardiac cushions. The transcription factor SOX9 is highly expressed in the cardiac cushion mesenchyme, and is essential for heart valve development. Loss of Sox9 in mouse cardiac cushion mesenchyme alters cell proliferation, embryonic survival, and valve formation. Despite this important role, little is known about how SOX9 regulates heart valve formation or its transcriptional targets. Therefore, we mapped putative SOX9 binding sites by ChIP-Seq in E12.5 heart valves, a stage at which the valve mesenchyme is actively proliferating and initiating differentiation. Embryonic heart valves have been shown to express a high number of genes that are associated with chondrogenesis, including several extracellular matrix proteins and transcription factors that regulate chondrogenesis. Therefore, we compared regions of putative SOX9 DNA binding between E12.5 heart valves and E12.5 limb buds. We identified context-dependent and context-independent SOX9-interacting regions throughout the genome. Analysis of context-independent SOX9 binding suggests an extensive role for SOX9 across tissues in regulating proliferation-associated genes including key components of the AP-1 complex. Integrative analysis of tissue-specific SOX9-interacting regions and gene expression profiles on Sox9-deficient heart valves demonstrated that SOX9 controls the expression of several transcription factors with previously identified roles in heart valve development, including Twist1, Sox4, Mecom and Pitx2. Together, our data identify SOX9-coordinated transcriptional hierarchies that control cell proliferation and differentiation during valve formation.
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Affiliation(s)
- Victoria C Garside
- Terry Fox Laboratory, BC Cancer Agency, Vancouver, Canada V5Z 1L3 Program in Cell and Developmental Biology, University of British Columbia, Vancouver, Canada V6T 1Z4
| | - Rebecca Cullum
- Terry Fox Laboratory, BC Cancer Agency, Vancouver, Canada V5Z 1L3
| | - Olivia Alder
- Terry Fox Laboratory, BC Cancer Agency, Vancouver, Canada V5Z 1L3
| | - Daphne Y Lu
- Terry Fox Laboratory, BC Cancer Agency, Vancouver, Canada V5Z 1L3
| | - Ryan Vander Werff
- Biomedical Research Centre, University of British Columbia, Vancouver, Canada V6T 1Z4
| | - Mikhail Bilenky
- Canada's Michael Smith Genome Sciences Centre, BC Cancer Agency, Vancouver, Canada V5Z 1L3
| | - Yongjun Zhao
- Canada's Michael Smith Genome Sciences Centre, BC Cancer Agency, Vancouver, Canada V5Z 1L3
| | - Steven J M Jones
- Canada's Michael Smith Genome Sciences Centre, BC Cancer Agency, Vancouver, Canada V5Z 1L3 Department of Medical Genetics, University of British Columbia, Vancouver, Canada V6T 1Z4 Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, Canada V5A 1S6
| | - Marco A Marra
- Canada's Michael Smith Genome Sciences Centre, BC Cancer Agency, Vancouver, Canada V5Z 1L3 Department of Medical Genetics, University of British Columbia, Vancouver, Canada V6T 1Z4
| | - T Michael Underhill
- Program in Cell and Developmental Biology, University of British Columbia, Vancouver, Canada V6T 1Z4 Biomedical Research Centre, University of British Columbia, Vancouver, Canada V6T 1Z4 Department of Medical Genetics, University of British Columbia, Vancouver, Canada V6T 1Z4
| | - Pamela A Hoodless
- Terry Fox Laboratory, BC Cancer Agency, Vancouver, Canada V5Z 1L3 Program in Cell and Developmental Biology, University of British Columbia, Vancouver, Canada V6T 1Z4 Department of Medical Genetics, University of British Columbia, Vancouver, Canada V6T 1Z4
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Wang Y, Wang Q, Guo C, Wang S, Qiu Y, Li H, Ma X. Decreased mRNA and protein expression of TWIST1 in myocardial tissue of fetuses with ventricular septal defects. Mol Med Rep 2015; 12:3089-94. [PMID: 25955272 DOI: 10.3892/mmr.2015.3734] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2014] [Accepted: 03/26/2015] [Indexed: 11/05/2022] Open
Abstract
Ventricular septal defect (VSD) is the most common type of congenital heart disease (CHD). The single gene mutations or absences that contribute to VSD development are well established; however, the aim of the present study was to measure gene expression variation between VSDs and normal fetal myocardial tissue. TWIST1, an important tumor biomarker, is a basic helix-loop-helix transcription factor that regulates cell proliferation, migration and differentiation in embryonic development and transformed tumor cells. Although growing evidence demonstrates that TWIST1 participates in a variety of human neoplastic diseases, the role of TWIST1 in VSD has remained elusive. Twenty-six VSD fetal myocardial tissue samples and 12 normal samples at matched gestational weeks (22-28 weeks) were included in the present study. Using reverse transcription quantitative polymerase chain reaction (PCR) and real-time PCR, it was demonstrated that TWIST1 mRNA was reduced by almost two-fold in the VSD samples compared with the normal samples. Western blot analysis also revealed that TWIST1 expression was decreased by ~three-fold (P=0.001) in the VSD samples compared with that in the normal samples. Of note, five complete ventricular (also called functionally univentricular or single ventricular) septal ageneses were identified among the specimens. For the five complete ventricular septal agenesis samples, similar results to those for other VSD fetal myocardial tissues were obtained. In conclusion, the results of the present study showed that TWIST1 mRNA and protein levels were reduced in VSDs. The present study was the first, to the best of our knowledge, to report that TWIST1 is not only a tumor biomarker, but may also be involved in the pathogenesis of VSD.
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Affiliation(s)
- Yuting Wang
- Department of Obstetrics and Gynecology, Shengjing Hospital of China Medical University, Shenyang, Liaoning 110004, P.R. China
| | - Qidi Wang
- Department of Genetics, National Research Institute for Family Planning, Beijing 100081, P.R. China
| | - Changlong Guo
- Department of Genetics, National Research Institute for Family Planning, Beijing 100081, P.R. China
| | - Shuo Wang
- Department of Obstetrics and Gynecology, Shengjing Hospital of China Medical University, Shenyang, Liaoning 110004, P.R. China
| | - Yue Qiu
- Department of Genetics, National Research Institute for Family Planning, Beijing 100081, P.R. China
| | - Hui Li
- Department of Obstetrics and Gynecology, Shengjing Hospital of China Medical University, Shenyang, Liaoning 110004, P.R. China
| | - Xu Ma
- Department of Genetics, National Research Institute for Family Planning, Beijing 100081, P.R. China
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Lee MP, Ratner N, Yutzey KE. Genome-wide Twist1 occupancy in endocardial cushion cells, embryonic limb buds, and peripheral nerve sheath tumor cells. BMC Genomics 2014; 15:821. [PMID: 25262113 PMCID: PMC4190347 DOI: 10.1186/1471-2164-15-821] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2014] [Accepted: 09/22/2014] [Indexed: 11/10/2022] Open
Abstract
Background The basic helix-loop-helix transcription factor Twist1 has well-documented roles in progenitor populations of the developing embryo, including endocardial cushions (ECC) and limb buds, and also in cancer. Whether Twist1 regulates the same transcriptional targets in different tissue types is largely unknown. Results The tissue-specificity of Twist1 genomic occupancy was examined in mouse ECCs, limb buds, and peripheral nerve sheath tumor (PNST) cells using chromatin immunoprecipitation followed by sequencing (Chip-seq) analysis. Consistent with known Twist1 functions during development and in cancer cells, Twist1-DNA binding regions associated with genes related to cell migration and adhesion were detected in all three tissues. However, the vast majority of Twist1 binding regions were specific to individual tissue types. Thus, while Twist1 has similar functions in ECCs, limb buds, and PNST cells, the specific genomic sequences occupied by Twist1 were different depending on cellular context. Subgroups of shared genes, also predominantly related to cell adhesion and migration, were identified in pairwise comparisons of ECC, limb buds and PNST cells. Twist1 genomic occupancy was detected for six binding regions in all tissue types, and Twist1-binding sequences associated with Chst11, Litaf, Ror2, and Spata5 also bound the potential Twist1 cofactor RREB1. Pathway analysis of the genes associated with Twist1 binding suggests that Twist1 may regulate genes associated with the Wnt signaling pathway in ECCs and limb buds. Conclusions Together, these data indicate that Twist1 interacts with genes that regulate adhesion and migration in different tissues, potentially through distinct sets of target genes. In addition, there is a small subset of genes occupied by Twist1 in all three tissues that may represent a core group of Twist1 target genes in multiple cell types. Electronic supplementary material The online version of this article (doi:10.1186/1471-2164-15-821) contains supplementary material, which is available to authorized users.
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Affiliation(s)
| | | | - Katherine E Yutzey
- Division of Molecular Cardiovascular Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio 45229, USA.
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Chang AC, Garside VC, Fournier M, Smrz J, Vrljicak P, Umlandt P, Fuller M, Robertson G, Zhao Y, Tam A, Jones SJM, Marra MA, Hoodless PA, Karsan A. A Notch-dependent transcriptional hierarchy promotes mesenchymal transdifferentiation in the cardiac cushion. Dev Dyn 2014; 243:894-905. [DOI: 10.1002/dvdy.24127] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2014] [Revised: 03/11/2014] [Accepted: 03/11/2014] [Indexed: 12/26/2022] Open
Affiliation(s)
- Alex C.Y. Chang
- Michael Smith Genome Sciences Centre; British Columbia Cancer Agency; Vancouver Canada
| | - Victoria C. Garside
- Terry Fox Laboratory; British Columbia Cancer Agency; Vancouver Canada
- Cell and Developmental Biology Program; University of British Columbia; Vancouver Canada
| | - Michele Fournier
- Michael Smith Genome Sciences Centre; British Columbia Cancer Agency; Vancouver Canada
- Department of Pathology and Laboratory Medicine; University of British Columbia; Vancouver Canada
| | - Justin Smrz
- Michael Smith Genome Sciences Centre; British Columbia Cancer Agency; Vancouver Canada
| | - Pavle Vrljicak
- Terry Fox Laboratory; British Columbia Cancer Agency; Vancouver Canada
| | - Patricia Umlandt
- Michael Smith Genome Sciences Centre; British Columbia Cancer Agency; Vancouver Canada
- Department of Pathology and Laboratory Medicine; University of British Columbia; Vancouver Canada
| | - Megan Fuller
- Michael Smith Genome Sciences Centre; British Columbia Cancer Agency; Vancouver Canada
- Department of Pathology and Laboratory Medicine; University of British Columbia; Vancouver Canada
| | - Gordon Robertson
- Michael Smith Genome Sciences Centre; British Columbia Cancer Agency; Vancouver Canada
| | - Yongjun Zhao
- Michael Smith Genome Sciences Centre; British Columbia Cancer Agency; Vancouver Canada
| | - Angela Tam
- Michael Smith Genome Sciences Centre; British Columbia Cancer Agency; Vancouver Canada
| | - Steven J. M. Jones
- Michael Smith Genome Sciences Centre; British Columbia Cancer Agency; Vancouver Canada
- Department of Medical Genetics; University of British Columbia; Vancouver Canada
| | - Marco A. Marra
- Michael Smith Genome Sciences Centre; British Columbia Cancer Agency; Vancouver Canada
- Department of Medical Genetics; University of British Columbia; Vancouver Canada
| | - Pamela A. Hoodless
- Terry Fox Laboratory; British Columbia Cancer Agency; Vancouver Canada
- Department of Medical Genetics; University of British Columbia; Vancouver Canada
| | - Aly Karsan
- Michael Smith Genome Sciences Centre; British Columbia Cancer Agency; Vancouver Canada
- Department of Pathology and Laboratory Medicine; University of British Columbia; Vancouver Canada
- Department of Pathology and Laboratory Medicine; British Columbia Cancer Agency; Vancouver Canada
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8
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MacGrogan D, Luxán G, de la Pompa JL. Genetic and functional genomics approaches targeting the Notch pathway in cardiac development and congenital heart disease. Brief Funct Genomics 2013; 13:15-27. [PMID: 24106100 DOI: 10.1093/bfgp/elt036] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
The Notch signalling pathway plays crucial roles in cardiac development and postnatal cardiac homoeostasis. Gain- and loss-of-function approaches indicate that Notch promotes or inhibits cardiogenesis in a stage-dependent manner. However, the molecular mechanisms are poorly defined because many downstream effectors remain to be identified. Genome-scale analyses are shedding light on the genes that are regulated by Notch signalling and the mechanisms underlying this regulation. We review the functional data that implicates Notch in cardiac morphogenetic processes and expression profiling studies that enlighten the regulatory networks behind them. A recurring theme is that Notch cross-talks reiteratively with other key signalling pathways including Wnt and Bmp to coordinate cell and tissue interactions during cardiogenesis.
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Affiliation(s)
- Donal MacGrogan
- Program of Cardiovascular Developmental Biology, Department of Cardiovascular Development and Repair, Centro Nacional de Investigaciones Cardiovasculares (CNIC), Melchor Fernández Almagro 3, 28029 Madrid, Spain. Tel.: +34-620-936633; Fax: +34-91-4531304;
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DeLaughter DM, Christodoulou DC, Robinson JY, Seidman CE, Baldwin HS, Seidman JG, Barnett JV. Spatial transcriptional profile of the chick and mouse endocardial cushions identify novel regulators of endocardial EMT in vitro. J Mol Cell Cardiol 2013; 59:196-204. [PMID: 23557753 DOI: 10.1016/j.yjmcc.2013.03.016] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/15/2013] [Revised: 03/15/2013] [Accepted: 03/21/2013] [Indexed: 11/17/2022]
Abstract
Valvular Interstitial Cells (VICs) are a common substrate for congenital and adult heart disease yet the signaling mechanisms governing their formation during early valvulogenesis are incompletely understood. We developed an unbiased strategy to identify genes important in endocardial epithelial-to-mesenchymal transformation (EMT) using a spatial transcriptional profile. Endocardial cells overlaying the cushions of the atrioventricular canal (AVC) and outflow tract (OFT) undergo an EMT to yield VICs. RNA sequencing (RNA-seq) analysis of gene expression between AVC, OFT, and ventricles (VEN) isolated from chick and mouse embryos at comparable stages of development (chick HH18; mouse E11.0) was performed. EMT occurs in the AVC and OFT cushions, but not VEN at this time. 198 genes in the chick (n=1) and 105 genes in the mouse (n=2) were enriched 2-fold in the cushions. Gene regulatory networks (GRN) generated from cushion-enriched gene lists confirmed TGFβ as a nodal point and identified NF-κB as a potential node. To reveal previously unrecognized regulators of EMT four candidate genes, Hapln1, Id1, Foxp2, and Meis2, and a candidate pathway, NF-κB, were selected. In vivo spatial expression of each gene was confirmed by in situ hybridization and a functional role for each in endocardial EMT was determined by siRNA knockdown in a collagen gel assay. Our spatial-transcriptional profiling strategy yielded gene lists which reflected the known biology of the system. Further analysis accurately identified and validated previously unrecognized novel candidate genes and the NF-κB pathway as regulators of endocardial cell EMT in vitro.
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Affiliation(s)
- Daniel M DeLaughter
- Department of Cell and Developmental Biology, Vanderbilt University Medical Center, Nashville, TN, USA
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