The rapidly emerging field of spatial biology research utilizes a multi-omic approach to characterizing the transcriptomic profiles heterogeneous organs and tissues, including the mammalian brain and associated tumors. RNAscopeTM in situ hybridization (ISH) assays enable visualization of single RNA molecules at the single-cell level whilst maintaining the tissue microenvironment and spatial context.
In this Spatial Biology Symposium, we will highlight the innovative research of three neuroscientists who leverage multi-omic technologies to provide insight to complex pathways and disease models
Session 1: 17:00 BST / 18:00 CEST / 09:00 PDT / 12:00 EDT
Title: Molecular characterization of retinal ganglion cell subtypes in the human retina
In this session, Brain Guy, Ph.D. postgraduate student at Johns Hopkins University, will discuss his research aiming to characterize the subtype diversity and development of human retinal ganglion cells (RGCs). RGCs are the projection neurons of the eye, and their axons constitute the optic nerve. Death or damage to RGCs results in many visual conditions, including glaucoma, which is one of the leading causes of human blindness. RGCs can be divided into many subtypes based on morphology, physiology, projection targets, and gene expression. However, the number of human RGC subtypes is unknown. To determine the number of RGC subtypes by gene expression, Guy is using RNAscope HiPlex ISH , immunohistochemical stains, and classical neurotracing methods. With these approaches, Guy has identified six RGC subtypes in the human eye so far.
The study of human eye development is incredibly difficult due to the limited access to genetically and pharmacologically manipulable tissue. In this webinar, Guy will explain that to obviate this issue, he uses human retinal organoids (human stem-cell-derived mini-retinas grown in a dish). These organoids recapitulate the developmental timing and cellular composition of the developing human retina. With this approach, Guy has thus far identified two RGC subtypes in human retinal organoids and will characterize more using HiPlex RNAscope ISH technology.
Learning Objectives:
- Understand how human RGC subtypes can be defined by the combinatorial expression of dozens of genes
- Learn how RNAscope HiPlex permits the identification of many of these subtypes in a single experiment
- Discover how human retinal organoids generate multiple RGC subtypes
Session 2: 18:00 BST / 19:00 CEST / 10:00 PDT / 13:00 EDT
Title: Mechanisms regulating homeostatic sleep pressure: The heterogeneity of hypothalamic Lhx6 neurons and their role in sleep
Sleep is a biological and physiological process necessary for organismal survival and wellbeing. When sleep is lost, this loss is compensated by extending and deepening subsequent sleep. This phenomenon, known as homeostatic sleep pressure, is thought to be one of the main regulatory processes of sleep, and to be conserved across phyla. Despite its physiological importance, the mechanisms underlying homeostatic sleep pressure are not well understood.
In this session, Parris Washington, Ph.D. student at Johns Hopkins University School of Medicine, will discuss a newly discovered novel population of GABAergic neurons in the hypothalamus that are activated in response to increasing sleep pressure after 6-hour sleep deprivation, either alone or in combination with 1 hour of recovery sleep. This self-innervating population of neurons, located in the ventral Zona Incerta (vZI), directly inhibits wake promoting Hcrt+ neurons in the lateral hypothalamus and express LIM homeodomain factor Lhx6. Lhx6 is a transcription factor that facilitates the tangential migration and organization of cortical interneurons but is not necessary for their survival. In contrast, hypothalamic Lhx6 positive GABAergic neurons require Lhx6 for their survival and only represent 45% and 33% of all Slc32a1+ and Gad1+ cells in the vZI, respectively.
In this presentation , Washington will discuss how she seeks to investigate the heterogeneity of this GABAergic Lhx6+ population in the hypothalamus and its role in homeostatic sleep pressure regulation using single-cell RNA analysis, including RNAscope™ HiPlex, as well as performing sleep deprivation on relevant mutant mouse models. With this work, Washington hopes to further elucidate the hypothalamic neural circuitry controlling homeostatic sleep pressure.
Learning Objectives:
- Understand that hypothalamic Lhx6 neurons are a heterogenous GABAergic population
- Learn how Calb1, Cck, Gal, and Nfia define molecularly distinct subtypes of Lhx6 neurons
- Discover how increased Fos activation is induced by elevated sleep pressure and persists even after several hours of recovery sleep
Session 3: 19:00 BST / 20:00 CEST / 11:00 PDT / 14:00 EDT
Title: Anterior thalamic dysfunction underlies cognitive deficits in psychiatric disease models
Neuropsychiatric disorders are often accompanied by cognitive impairments or intellectual disability (ID). However, it is not clear whether there are converging mechanisms underlying these debilitating impairments. Through his group’s research, Dheeraj Roy, Ph.D., of the Broad Institute of MIT and Harvard, has found that many autism and schizophrenia risk genes are expressed in the anterodorsal (AD) subdivision of anterior thalamic nuclei, which has reciprocal connectivity with learning and memory structures.
CRISPR-Cas9 knockdown of multiple risk genes selectively in the AD thalamus leads to memory deficits. But, while AD is necessary for contextual memory encoding, the neighboring anteroventral (AV) subdivision is what regulates memory specificity. These distinct functions of the AD and AV are mediated through their projections to the retrosplenial cortex, using differential mechanisms. Furthermore, knockdown of autism and schizophrenia risk genes - PTCHD1, YWHAG, or HERC1 -from the AD led to neuronal hyperexcitability, and normalization of hyperexcitability rescued memory deficits in these models.
In this session, Roy discusses his study to identify converging cellular to circuit mechanisms underlying cognitive deficits in a subset of neuropsychiatric disease models.
Learning Objectives:
- Explore the role of the thalamus in cognition
- Understand the converging mechanisms underlying cognitive deficits in different disease models
- Discover how to rescue cognition by targeting thalamocortical
Watch the On-demand ACD | SelectScience Spatial Biology Symposium here:
