National Institute of Child Health and Human Development (NICHD)

Synaptic plasticity is fundamental to nervous system development and function.  Our labs have been studying BMP and reactive oxygen species (ROS) signalling as key regulators of synapse development, growth and plasticity. For example, during critical periods of nervous system development, metabolic ROS generated in mitochondria specify the functional ‘baseline’, including through setting the size and composition of synaptic terminals. The mechanisms by which this is achieved can now be explored. Specifically, we are now investigating:
 -    novel facets of BMP signalling, and their roles in regulating synapse size, composition and transmission properties;
 -    how transient critical period experiences in the late embryo lead to dramatic, lasting changes in gene expression and neuronal function.  

This project will combine biochemical and genetic approaches with electrophysiology and methods for high-end imaging. We expect this project to redefine our understanding of how multiple signalling pathways, working at different time scales and regulating distinct elements of plasticity, integrate at the synapse.

Creatine is an important energy storage and transfer molecule in muscle and brain but is synthesized primarily in the kidneys and liver. Hence, creatine uptake in skeletal muscle, brain, and heart is dependent on the creatine transporter (CrT or SLC6A8). Loss-of-function mutations in CrT are the second most common cause of X-linked intellectual disability and low tissue creatine levels result in skeletal muscle atrophy and are closely associated with heart failure. Cells down-regulate expression of CrT when creatine levels are high, but the mechanisms underlying this autoregulation and the importance to normal physiology and disease are unknown.

Recently, we found that creatine feedback inhibits translation of the CrT mRNA to control transporter production, and we identified elements in the CrT mRNA that are important for this control. This PhD project will involve molecular genetic analyses to more fully characterize the translational control mechanism(s) by which creatine feedback inhibits its own cellular uptake. In addition, CRISPR-Cas technology will be used to eliminate the translational control mechanisms in mice, and then physiological studies of the mice will be used to characterize the role of CrT autoregulation.

The posterior Lateral Line primordium is a group of about a hundred cells that migrates under the skin, from the ear to the tip of the tail, periodically forming and depositing sensory organs called neuromasts, to spearhead formation of the zebrafish Lateral Line sensory system. In recent years, this relatively simple and accessible system has emerged as an attractive model for understanding various aspects of morphogenesis in the developing embryo, including the guidance of cell migration, tissue patterning and organ formation. The goal is to use a combination of cellular, molecular, genetic and biomechanical manipulations coupled with live imaging, image processing and the development of multi-scale computational models to understand the self-organization of cell-fate, morphogenesis and migration of the lateral line primordium. Specific focus will be on developing tools and methods for investigating, imaging, quantifying and modelling the mechanics of collective migration, morphogenesis of epithelial rosettes and the intercellular and intracellular signaling networks that coordinate lateral line primordium development.

A signalling pathway linking nutrient availability to changes in gene expression that hinges on the phosphorylation of translation initiation 2 (eIF2) has long been known to exist. Recognized initially as the yeast General Control Response, recent convergent lines of research have implicated its metazoan counterpart, the Integrated Stress Response, in diverse physiological processes ranging from immunity to memory formation.

This PhD programme will exploit our emerging detailed understanding of translation initiation and termination to shed light on unanticipated mechanistic aspects of the ISR. An understanding of these details may inform efforts to target the ISR to therapeutic ends.

Unusual RNA/DNA structures (R-loops) are formed when the RNA hybridizes to a complementary DNA strand, displacing the other DNA strand in this process. R-loops are formed in all living organisms and play crucial roles in regulating gene expression, DNA and histone modifications, generation of antibody diversity, DNA replication and genome stability. R-loops are also implicated in human diseases, including neurodegeneration, cancer mitochondrial diseases and HIV-AIDs.

Collaboration between Prof Crouch (NIH) and Dr. Gromak (Oxford) labs will focus on understanding the regulation of R-loops and uncover the molecular mechanisms which lead to R-loop-associated diseases. We will employ state-of-the-art techniques including CRISPR, Mass Spectrometry and molecular biology approaches to understand the principles of R-loop biology in health and disease conditions. In the long term the findings from this project will be essential for the development of new therapeutic approaches for R-loop-associated disorders.

*This project is available for the 2021 Oxford-NIH Pilot Programme*

The project will use X-ray crystallography, cryoEM, microbial genetics and molecular biology to explore how small RNAs and small proteins act as regulators with speed and precision in diverse bacteria.

Neuronal plasticity is fundamental to nervous system development and function. We have recently discovered that reactive oxygen species (ROS), known for their destructive capacity in the ageing or diseased brain, function as second messengers for implementing structural plasticity at synaptic terminals. Moreover, different sources of ROS (cytoplasmic vs mitochondrially generated) regulate genetically distinct aspects of synapse development (growth vs release site number). Do ROS sculpt synapse plasticity in response to the metabolic state of neurons? How does ROS signaling intersect with other signaling pathways regulating synaptic plasticity, such as BMP and Wnt? This project will combine biochemical and genetic approaches with electrophysiology and methods for live and super-resolution imaging to investigate the contribution of various signaling pathways to synapse plasticity. We expect this project to redefine our understanding of how multiple signaling pathways integrate at the synapse to regulate distinct elements of plasticity.

Undertake genomic and epigenomic studies into the mechanisms of tumorigenesis in individuals with inherited predisposition to neuroendocrine tumor syndromes, especially pheochromocytoma/paraganglioma associated with mutations in the Krebs cycle. Such discoveries can lead to understanding of developmental and other mechanisms in these tumors related to the same syndrome but behaving in a different way and occurring in different tissue of origin. Such data can be paramount to study novel therapeutic approaches for these tumors based on the discovery on novel tumor-specific targets as well as biomarkers.