Research Projects

Cardiogenesis

A major focus of the laboratory is to understand the mechanisms underlying mammalian cardiogenesis and congenital heart disease.

Transcription factor networks in cardiogenesis

Using protein interaction cloning and gene knockout studies, we have established a cardiogenetic transcription factor network consisting of the histone acetyltransferases EP300 and CREBBP, the transcription coactivator Cited2 and the transcription factors TFAP2 and LMO4. Targets of this network are the Nodal-Pitx2c left right patterning pathway, the polycomb genes (Bmi1, Mel18 and Rnf2) which form the PRC1 histone ubiquitylating complex, and the transcription factor Tbx1. We have shown that members of this network (Cited2 and Pitx2) interact with the maternal diet to control left-right patterning. We are currently using recombineering methods to investigate the role of Cited2 gene mutations found in patients with congenital heart disease. these projects are funded by a Wellcome Trust Program Grant.

Tbx1

Tbx1 is the major gene responsible for the 22q11 deletion or DiGeorge syndrome, in which ~75% of patients have congenital heart defects. As part of the EU FP7-Cardiogenet network, we are investigating the function of a novel Tbx1 mutation ("George") identified through ENU mutagenesis. We have developed protein complementation approaches to identify Tbx1 protein interactions in living cells, and have identified several novel interactors. In collaboration with Erika Mancini, we are working to solve the structure of Tbx1. A major interest is to understand the genetic interactions that suppress the expression of the 22q11 deletion cardiac phenotype in many patients.  

Signalling pathways in cardiogenesis

Using ENU mutagenesis together with magnetic resonance imaging, we have identified several novel genes that are required for cardiogenesis. Cardiogenetic signalling pathways include the BMP/TGF-β, WNT, NOTCH, hedgehog (HH), FGFR and EGFR pathways. These pathways control embryonic heart development, and are important in maintaining homeostasis of the adult heart. Of particular interest is BMP signalling which plays key roles in myocardial fibrosis, angiogenesis, pulmonary hypertension and pluripotency. Using ENU mutagenesis and magnetic resonance imaging we have identified several genes (e.g Pcsk5) that are biochemically predicted to impact on cardiogenetic signalling pathways. We are now exploring the role of these genes in vivo using pathway sensors. In addition at the BHF Centre for Cardiovascular Target Discovery, we are using high-througput screens to identify novel genes within cardiogenetic signalling pathways. These projects are funded by a BHF Program Grant.

Genetic architecture of congenital heart disease

Approximately ~8% of CHD is inherited in Mendelian fashion, with the rest being sporadic.  Major mechanisms of sporadic CHD include chromosomal causes such as Trisomy 21 and 22q11 deletion, which account for approximately 12%.  Non-synonymous point mutations in cardiac developmental genes have also been found in case-control candidate gene association studies. We are investigating the genetic architecture in patients with CHD, using exon-resequencing of candidate genes (UK10K study) and genome-wide association studies. We have developed a national network (the GO-CHD study) for recruiting patients to these studies.  We are also developing approaches to translate these discoveries to clinical care in the NHS.

Cell -based assays to identify genetic interactions

Genetic interactions are a powerful tool to identify pathways through which a gene functions, and also mechanisms that modify phenotypic expression or penetrance of a gene mutation. While genetic interaction screens have been performed in yeast, worms and fly, they are difficult in mammalian models. We are beginning to use fibroblast cells obtained from knockout models with cardiac developmental defects, and phenotyping them in great detail using high content multiparametric imaging approaches. Once these cellular phenotypes are identifies we will screen for suppressors and enhancers using a genome-wide siRNA approach.  We have a postdoctoral vacancy available here.

BHF Centre for Cardiovascular Target Discovery

This is a new program to use high-throughput and high-content cell-based genetic and small molecule screens to identify key genetic pathways that mediate cardiovascular disease, and to identify and validate novel druggable targets within these pathways. A major effort in the laboratory is to develop novel cell-based screens that are relevant to cardiovascular disease. Please see the BHF Centre for Cardiovascular Target Discovery website for further details.

Collaborations