MEF2C regulates outflow tract alignment and transcriptional control of Tdgf1

Congenital heart defects are the most common birth defects in humans, and those that affect the proper alignment of the outflow tracts and septation of the ventricles are a highly significant cause of morbidity and mortality in infants. A late differentiating population of cardiac progenitors, referred to as the anterior second heart field (AHF), gives rise to the outflow tract and the majority of the right ventricle and provides an embryological context for understanding cardiac outflow tract alignment and membranous ventricular septal defects. However, the transcriptional pathways controlling AHF development and their roles in congenital heart defects remain incompletely elucidated. Here, we inactivated the gene encoding the transcription factor MEF2C in the AHF in mice. Loss of Mef2c function in the AHF results in a spectrum of outflow tract alignment defects ranging from overriding aorta to double-outlet right ventricle and dextro-transposition of the great arteries. We identify Tdgf1, which encodes a Nodal co-receptor (also known as Cripto), as a direct transcriptional target of MEF2C in the outflow tract via an AHFrestricted Tdgf1 enhancer. Importantly, both the MEF2C and TDGF1 genes are associated with congenital heart defects in humans. Thus, these studies establish a direct transcriptional pathway between the core cardiac transcription factor MEF2C and the human congenital heart disease gene TDGF1. Moreover, we found a range of outflow tract alignment defects resulting from a single genetic lesion, supporting the idea that AHF-derived outflow tract alignment defects may constitute an embryological spectrum rather than distinct anomalies

Vascular Platform to Define Hematopoietic Stem Cell Factors and Enhance Regenerative Hematopoiesis

SummaryHematopoietic stem cells (HSCs) inhabit distinct microenvironments within the adult bone marrow (BM), which govern the delicate balance between HSC quiescence, self-renewal, and differentiation. Previous reports have proposed that HSCs localize to the vascular niche, comprised of endothelium and tightly associated perivascular cells. Herein, we examine the capacity of BM endothelial cells (BMECs) to support ex vivo and in vivo hematopoiesis. We demonstrate that AKT1-activated BMECs (BMEC-Akt1) have a unique transcription factor/cytokine profile that supports functional HSCs in lieu of complex serum and cytokine supplementation. Additionally, transplantation of BMEC-Akt1 cells enhanced regenerative hematopoiesis following myeloablative irradiation. These data demonstrate that BMEC-Akt1 cultures can be used as a platform for the discovery of pro-HSC factors and justify the utility of BMECs as a cellular therapy. This technical advance may lead to the development of therapies designed to decrease pancytopenias associated with myeloablative regimens used to treat a wide array of disease states

Transcriptional regulation of Gata4 in the developing heart

The mammalian heart forms from multiple embryonic lineages whose specification and contributions to the developing heart are exquisitely controlled by transcription factors and signaling molecules. GATA4 is a zinc finger transcription factor that is expressed in multiple cardiovascular lineages and is required for embryonic viability. GATA4 controls heart development by regulating gene expression in multiple embryonic lineages, including the endocardium, which is an inner lining of specialized cardiac endothelium, and the myocardium, which is the muscular layer of the heart. In spite of its importance in heart development, the transcriptional pathways upstream of Gata4 in the developing heart were previously unknown. Here, we describe several enhancers from the mouse Gata4 locus that are active in the embryo and focus on a distal enhancer that is active in multiple cardiac lineages early in heart development. Detailed expression and lineage analyses show that the cardiac Gata4 enhancer is active in both myocardial and endocardial lineages when the heart first forms but restricts to the endocardium as the heart undergoes looping and further development. This pattern of activity requires GATA-binding sites, which appear to play a role in the repression of enhancer activity in extracardiac tissues in the embryo. The activation of this enhancer in transgenic embryos and in cultured aortic endothelial cells is dependent on four ETS sites. To identify which ETS transcription factors might be involved in Gata4 regulation via the ETS sites in the enhancer, we determined the expression profile of 24 distinct ETS factors in embryonic mouse hearts. Among multiple ETS transcripts present, ETS1, FLI1, ETV1, ETV5, ERG, and ETV6 were the most abundant in the early embryonic heart. We found that ETS1, FLI1, and ERG were strongly expressed in the heart at embryonic day 8.5 and that ETS1 and ERG bound to the endogenous Gata4 enhancer in cultured endothelial cells. FLI1 and ERG activated the enhancer in a fibroblast cell line. Thus, these studies define the ETS expression profile in the early embryonic heart and identify an ETS-dependent cardiac enhancer from the Gata4 locus

Development of Outcome Assessments at WPI

The WPl PLAN, adopted by the WPl faculty in 1970, strongly anticipates current thinking about student outcomes assessments by structuring degree requirements that mandate that students demonstrate their ability to perform professional functions embodied in ABET Criteria 2000, especially Criteria 3 and 4. The WPI faculty has also practiced both student and self evaluations of these outcomes through respectively grades and peer review (both departmental and campus-wide) of student performance

An endoderm-specific transcriptional enhancer from the mouse Gata4 gene requires GATA and homeodomain protein binding sites for function in vivo

21 páginas, 6 figuras.-- El PDF es el manuscrito de autor.Several transcription factors function in the specification and differentiation of the endoderm, including the zinc finger transcription factor GATA4. Despite its essential r ole in endoderm development, the transcriptional control of the Gata4 gene in the developing endoderm and its derivatives remains incompletely understood. Here, we identify a distal enhancer from the Gata4 gene, which directs expression exclusively to the visceral and definitive endoderm of transgenic mouse embryos. The activity of this enhancer is initially broad within the definitive endoderm but later restricts to developing endoderm-derived tissues, including pancreas, glandular stomach, and duodenum. The activity of this enhancer in vivo is dependent on evolutionarily-conserved HOX and GATA binding sites, which are bound by PDX-1 and GATA4, respectively. These studies establish Gata4 as a direct transcriptional target of homeodomain and GATA transcription factors in the endoderm and support a model in which GATA4 functions in the transcriptional network for pancreas formation.This work was supported by grants HL64658 and AR52130 from the NIH to BLB.Peer reviewe

What Was Learned - Outcomes Assessment Under Criteria 2000 At WPI

Six WPI engineering programs were evaluated under Criteria 2000 during a pilot accreditation visit in 1996. The WPI PLAN consists of degree requirements focused on the achievement of outcomes related to those of Criteria 2000. The mapping of degree requirement outcomes to the elements of the Criteria hinged on the translation of student performance metrics and their interpretation. Not surprisingly, substantial effort was necessary to ensure the identification of all elements of Criteria 2000, including the applicable Program Criteria in the academic program outcomes

Direct transcriptional regulation of Gata4 during early endoderm specification is controlled by FoxA2 binding to an intronic enhancer

10 páginas, 7 figuras.-- PMCID: PMC2945415The embryonic endoderm is a multipotent progenitor cell population that gives rise to the epithelia of the digestive and respiratory tracts, the liver and the pancreas. Among the transcription factors that have been shown to be important for endoderm development and gut morphogenesis is GATA4. Despite the important role of GATA4 in endoderm development, its transcriptional regulation is not well understood. In this study, we identified an intronic enhancer from the mouse Gata4 gene that directs expression to the definitive endoderm in the early embryo. The activity of this enhancer is initially broad in all endodermal progenitors, as demonstrated by fate mapping analysis using the Cre/loxP system, but becomes restricted to the dorsal foregut and midgut, and associated organs such as dorsal pancreas and stomach. The function of the intronic Gata4 enhancer is dependent upon a conserved Forkhead transcription factor-binding site, which is bound by recombinant FoxA2 in vitro. These studies identify Gata4 as a direct transcriptional target of FoxA2 in the hierarchy of the transcriptional regulatory network that controls the development of the definitive endoderm.This work was supported by funds from the Instituto Salud Carlos III (CP07/00120, PI080018), Consejería Salud Junta de Andalucía (PI0008) and CIBERDEM to AR and by NIH grants HL099707, HL064658, and DE019118 to BLB.Peer reviewe

Achieving Learning Outcomes through Project-Based Education

The WPI Plan is predicated on the concept that project work provides an environment in which students “learn by doing.” In addition to requiring disciplinary competence, WPI’s undergraduate programs feature broad learning outcomes such as the ability to address open-ended problems, to communicate effectively, to function well in teams, and to understand the societal and cultural contexts within which science and technology function. A set of required projects is central to the achievement and demonstration of such learning outcomes. As a practical matter, we have found that problems drawn from the “real world” provide very effective learning experiences for students working in small teams with guidance from faculty advisors and sponsor liaisons. WPI students complete two such projects--an interactive technology/society project done in multidisciplinary teams, and a capstone design or research project in the major area of study. Both of these projects are degree requirements for every WPI student. Assessment indicates that these experiences are especially effective contexts for motivating high levels of student achievement. Because of WPI’s well-established project-based approach to global learning, the Global Perspective Program, more than 500 WPI students participated last year in semester-long study-abroad programs culminating in a major team-based project. The WPI Global Perspective Program presently provides opportunities at over twenty sites for students to complete disciplinary and interdisciplinary projects — all of which are advised by faculty in residence with the students at the global site. In this paper, we will discuss the educational objectives of these two types of student projects in terms of outcomes and their assessment. In particular, we will focus on the challenges and benefits of achieving and measuring broad learning outcomes in open-ended project settings. Some of these learning outcomes are particularly well-suited to demonstrating fulfillment of ABET criteria, including those criteria that are mostdifficult to achieve in a conventional, course-based curriculum. We will conclude by describing how the evidence provided by assessing these projects has been used in two highly successful ABET EC 2000 reviews