title: RNA-seq analysis to identify novel roles of scleraxis during embryonic mouse heart valve remodeling.
abstract: Heart valve disease affects up to 30% of the population and has been shown to have origins during embryonic development. Valvulogenesis begins with formation of endocardial cushions in the atrioventricular canal and outflow tract regions. Subsequently, endocardial cushions remodel, elongate and progressively form mature valve structures composed of a highly organized connective tissue that provides the necessary biomechanical function throughout life. While endocardial cushion formation has been well studied, the processes required for valve remodeling are less well understood. The transcription factor Scleraxis (Scx) is detected in mouse valves from E15.5 during initial stages of remodeling, and expression remains high until birth when formation of the highly organized mature structure is complete. Heart valves from Scx-/- mice are abnormally thick and develop fibrotic phenotypes similar to human disease by juvenile stages. These phenotypes begin around E15.5 and are associated with defects in connective tissue organization and valve interstitial cell differentiation. In order to understand the etiology of this phenotype, we analyzed the transcriptome of remodeling valves isolated from E15.5 Scx-/- embryos using RNA-seq. From this, we have identified a profile of protein and non-protein mRNAs that are dependent on Scx function and using bioinformatics we can predict the molecular functions and biological processes affected by these genes. These include processes and functions associated with gene regulation (methyltransferase activity, DNA binding, Notch signaling), vitamin A metabolism (retinoic acid biosynthesis) and cellular development (cell morphology, cell assembly and organization). In addition, several mRNAs are affected by alternative splicing events in the absence of Scx, suggesting additional roles in post-transcriptional modification. In summary, our findings have identified transcriptome profiles from abnormal heart valves isolated from E15.5 Scx-/- embryos that could be used in the future to understand mechanisms of heart valve disease in the human population.
authors.affiliation: Molecular and Cellular Pharmacology Graduate Program, Leonard M. Miller School of Medicine, Miami, Florida, United States of America; Center for Cardiovascular and Pulmonary Research and The Heart Center at Nationwide Children's Hospital Research Institute, Columbus, Ohio, United States of America.
authors.forename: Damien N
authors.initials: DN
authors.lastname: Barnette
authors.affiliation: Center for Cardiovascular and Pulmonary Research and The Heart Center at Nationwide Children's Hospital Research Institute, Columbus, Ohio, United States of America; Molecular, Cellular and Developmental Biology Graduate Program, The Ohio State University, Columbus, Ohio, United States of America.
authors.forename: Matthew
authors.initials: M
authors.lastname: VandeKopple
authors.affiliation: Ocean Ridge Biosciences LLC, Palm Beach Gardens, Florida, United States of America.
authors.forename: Yonggan
authors.initials: Y
authors.lastname: Wu
authors.affiliation: Ocean Ridge Biosciences LLC, Palm Beach Gardens, Florida, United States of America.
authors.forename: David A
authors.initials: DA
authors.lastname: Willoughby
authors.affiliation: Center for Cardiovascular and Pulmonary Research and The Heart Center at Nationwide Children's Hospital Research Institute, Columbus, Ohio, United States of America; Department of Pediatrics, The Ohio State University, Columbus, Ohio, United States of America.
authors.forename: Joy
authors.initials: J
authors.lastname: Lincoln
mesh_terms: D000818:Animals; D051792:Basic Helix-Loop-Helix Proteins / Q000235:genetics / Q000378:metabolism*; D018507:Gene Expression Regulation, Developmental; D006349:Heart Valve Diseases / Q000196:embryology* / Q000235:genetics / Q000473:pathology; D006351:Heart Valves / Q000196:embryology* / Q000473:pathology; D006801:Humans; D051379:Mice; D018345:Mice, Knockout; D012333:RNA, Messenger / Q000096:biosynthesis* / Q000235:genetics; D017423:Sequence Analysis, RNA
chemical_list: D051792:Basic Helix-Loop-Helix Proteins; D012333:RNA, Messenger; C503815:Scx protein, mouse