Biomedical Imaging Postdocs
- Ross A. Poché, Ph.D. Neuronal degeneration lies at the heart of a spectrum of debilitating human cognitive and motor diseases including Alzheimer’s and Parkinson’s disease as well as sensory diseases such as blindness. By characterizing cell populations within the retina, which have the ability to generate new neurons, therapeutic approaches could be employed to harness the ability of these cells to cure human neurological diseases. The objective of my research is to determine the potential of the mammalian retina for repair via endogenous mechanisms. In response to retinal damage, Müller glial (MG) cells of several vertebrate model systems have been shown to give rise to new retinal neurons. However, in mammals, there is a paucity of data directly testing the regenerative capacity of MG cells in vivo. My central hypothesis is that, in response to retinal damage, mature mouse MG cells possess the ability to re-enter the cell cycle and trans-differentiate into retinal neurons. The overall goal of my research is to test this hypothesis by performing genetic, Cre-loxP fate mapping experiments and time lapse imaging of retinal explants. I also aim to characterize the molecular pathways which confer stem cell-like ability upon the MG cells. Preliminary data suggests that the transcription factor, Sox9 may function in such a manner.
Another area of interest is characterization of the damaged retinal environment as it relates to neovascularization. Data from patients and animal models have suggested that early events of diabetic retinopathy show a very tight correlation with the appearance of reactive MG cells and subsequent neo-vascularization. However, this relationship is not well understood. Also, mice which undergo constitutive reactive gliosis or suffering from acute retinal damage exhibit significant increases in vessel branching and size. By rigorously characterizing the vascular structure of damaged retinae derived from various genetic contexts, I will gain insight into primary affected vascular cell types and subsequent overall vascular changes. With such data, I will be in a position to develop new hypotheses on the vasculature’s role during retinal repair to test in future studies.
- Ryan Seamon Udan, Ph.D. Our laboratory is interested in understanding how the processes of vessel development are regulated by hemodynamic force. However, very little is known about how hemodynamic forces can promote pathway activation, and the regulation of downstream target genes. In addition, conflicting theories about the role of hemodynamic force in the regulation of vessel identity (arteries versus veins) need to be discerned. The goals of my studies are 1) to identify vascular remodeling target genes that are regulated by hemodynamic force, and 2) to determine whether hemodynamic forces influence the commitment of endothelial cells to artery or vein fates. The elucidation of the mechanisms behind these processes will have important consequences in our understanding of cardiovascular abnormalities.
- Tegy John Vadakkan, Ph.D. My research focuses on three topics: quantifying angiogenesis, mapping the neural stem cell niche in an adult mouse brain, and using two photon infra red lasers for confocal imaging. It is well known that the vascular endothelial cells that line the inner surface of a blood vessel respond to changes in shear stress. Using the blood vessels in the yolk sacs of mouse embryos, I am trying to find out how the diameter of a blood vessel changes with the number of endothelial cells during development.
Also, I am working on mapping the neural stem cell niche in the sub-ependymal zone (SEZ) of the adult mouse brain. Using confocal microscopy and modified watershed algorithms I am trying to catalogue the cell types in the niche, as well as the proximity of the cell types to the blood vessels and the ventricles in the SEZ. I have been involved in modifying the beam path and power output of a two-photon laser that works in the infra red range. Using the new laser set up coupled to the confocal microscope we were able to take deep tissue images which were not possible using a simple confocal microscope.