How are the epileptogenesis clocks ticking?
The epileptogenesis process is associated with large-scale changes in gene expression, which contribute to the remodelling of brain networks permanently altering excitability. About 80% of the protein coding genes are under the influence of the circadian rhythms. These are 24-hour endogenous rhythms that determine a large number of daily changes in physiology and behavior in our bodies. In the brain, the master clock regulates a large number of pathways that are important during epileptogenesis and established-epilepsy, such as neurotransmission, synaptic homeostasis, inflammation, blood-brain barrier among others. In-depth mapping of the molecular basis of circadian timing in the brain is key for a complete understanding of the cellular and molecular events connecting genes to phenotypes.
Spatial and Single Cell Genomics for Next Generation Neuroscience
The advent of next generation sequencing ushered in a ten-year period of exuberant technology development, enabling the quantification of gene expression and epigenetic features within individual cells, and within intact tissue sections. In this seminar, I will outline our technological contributions, beginning with the development of Drop-seq, a method for high-throughput single cell analysis, followed by the development of Slide-seq, a technique for measuring genome-wide expression at 10 micron spatial resolution. Using a combination of these techniques, we recently constructed a comprehensive cell type atlas of the adult mouse brain, positioning cell types within individual brain structures. I will discuss the major findings from this dataset, including emerging principles of neurotransmission, and the localization of disease gene signatures to specific cell types. Finally, I will introduce a new spatial technology, Slide-tags, that unifies single cell and spatial genomics into a single, highly scalable assay.
Analyzing Retinal Disease Using Electron Microscopic Connectomics
John DowlingJohn E. Dowling received his AB and PhD from Harvard University. He taught in the Biology Department at Harvard from 1961 to 1964, first as an Instructor, then as assistant professor. In 1964 he moved to Johns Hopkins University, where he held an appointment as associate professor of Ophthalmology and Biophysics. He returned to Harvard as professor of Biology in 1971, was the Maria Moors Cabot Professor of Natural Sciences from 1971-2001, Harvard College professor from 1999-2004 and is presently the Gordon and Llura Gund Professor of Neurosciences. Dowling was chairman of the Biology Department at Harvard from 1975 to 1978 and served as associate dean of the faculty of Arts and Sciences from 1980 to 1984. He was Master of Leverett House at Harvard from 1981-1998 and currently serves as president of the Corporation of The Marine Biological Laboratory in Woods Hole. He is a Fellow of the American Academy of Arts and Sciences, a member of the National Academy of Sciences and a member of the American Philosophical Society. Awards that Dowling received include the Friedenwald Medal from the Association of Research in Ophthalmology and Vision in 1970, the Annual Award of the New England Ophthalmological Society in 1979, the Retinal Research Foundation Award for Retinal Research in 1981, an Alcon Vision Research Recognition Award in 1986, a National Eye Institute's MERIT award in 1987, the Von Sallman Prize in 1992, The Helen Keller Prize for Vision Research in 2000 and the Llura Ligget Gund Award for Lifetime Achievement and Recognition of Contribution to the Foundation Fighting Blindness in 2001. He was granted an honorary MD degree by the University of Lund (Sweden) in 1982 and an honorary Doctor of Laws degree from Dalhousie University (Canada) in 2012. Dowling's research interests have focused on the vertebrate retina as a model piece of the brain. He and his collaborators have long been interested in the functional organization of the retina, studying its synaptic organization, the electrical responses of the retinal neurons, and the mechanisms underlying neurotransmission and neuromodulation in the retina. Dowling became interested in zebrafish as a system in which one could explore the development and genetics of the vertebrate retina about 20 years ago. Part of his research team has focused on retinal development in zebrafish and the role of retinoic acid in early eye and photoreceptor development. A second group has developed behavioral tests to isolate mutations, both recessive and dominant, specific to the visual system.
Synaptic health in Parkinson's Disease
Parkinson's disease (PD) is the second most common neurodegenerative disorder, affecting 1% of over 65's; there is currently no effective treatment. Dopaminergic neuronal loss is hallmark in PD and yet despite decades of intensive research there is still no known therapeutic which will completely halt the disorder. As a result, identification of interventive therapies to reverse or prevent PD are essential. Using genetically faithful models (induced pluripotent stem cells and knock-in mice) of familial late onset PD (LRRK2 G2019S and GBA N370S) we have contributed to the literature that neuronal dysfunction precedes degeneration. Specifically, using whole cell patch clamp electrophysiology, biochemical, behavioural and molecular biological techniques, we have begun to investigate the fundamental processes that make neurons specialised i.e., synaptic function and neurotransmission. We illustrate those alterations to spontaneous neurotransmitter release, neuronal firing, and short-term plasticity as well as Ca2+ and energy dyshomeostasis, are some of the earliest observable pathological dysfunctions and are likely precursors to late-stage degeneration. These pathologies represent targets which can be manipulated to address causation, rather than the symptoms of the PD, and represent a marker that, if measurable in patients, could form the basis of early PD detection and intervention.
Unique Molecular Regulation of Prefrontal Cortex Confers Vulnerability to Cognitive Disorders
The Arnsten lab studies molecular influences on the higher cognitive circuits of the dorsolateral prefrontal cortex (dlPFC), in order to understand mechanisms affecting working memory at the cellular and behavioral levels, with the overarching aim of identifying the actions that render the dlPFC so vulnerable in cognitive disorders. Her lab has shown that the dlPFC has unique neurotransmission and neuromodulation compared to the classic actions found in the primary visual cortex, including mechanisms to rapidly weaken PFC connections during uncontrollable stress. Reduced regulation of these stress pathways due to genetic or environmental insults contributes to dlPFC dysfunction in cognitive disorders, including calcium dysregulation and tau phosphorylation in the aging association cortex. Understanding these unique mechanisms has led to the development of a new treatment, IntunivTM, for a variety of PFC disorders.