RP3: Cell Phenotyping: Intrinsic physiology and genetic characteristics

RP3：细胞表型：内在生理学和遗传特征

• 批准号: 10011920
• 负责人: SAMUEL L. PFAFF
• 金额: $ 70.9万
• 依托单位: SALK INSTITUTE FOR BIOLOGICAL STUDIES
• 依托单位国家: 美国
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-09-15 至 2024-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10011920
• 关键词: Adult; Behavior Control; Bioinformatics; Biophysics; Categories; Cell Count; Cell Lineage; Cell Separation; Cells; Cervical; Characteristics; Code; Complex; Complex Mixtures; Data; Development; Elbow; Electric Capacitance; Electrophysiology (science); Forelimb; Foundations; Freedom; Gene Expression Profile; Genes; Genetic; Genetic Heterogeneity; Genetic Variation; Goals; Heterogeneity; Individual; Interneurons; Joints; Label; Link; Location; Maps; Mediating; Membrane; Methods; Modeling; Molecular; Molecular Genetics; Motor; Motor Neurons; Movement; Mus; Muscle; Neurons; Neurosciences; Operative Surgical Procedures; Output; Pathway interactions; Pattern; Phenotype; Physiological; Physiology; Population; Population Heterogeneity; Positioning Attribute; Process; Property; Rabies; Reporter; Resistance; Slice; Spinal; Spinal Cord; Subcellular Anatomy; Synapses; System; Testing; Wrist; base; biophysical properties; cell type; combinatorial; experimental study; genetic manipulation; genetic profiling; indexing; limb movement; motor behavior; neural network; patch clamp; predictive modeling; protein expression; single cell sequencing; single-cell RNA sequencing; tool; transcription factor; transcriptome; transcriptomics

Summary: Project 3 – Cell Phenotyping: Intrinsic Physiology and Genetic Characteristics The identification of developmental pathways and neuronal subtype markers has made circuit studies of the spinal cord one of the most tractable CNS systems to investigate how neural networks control behaviorally relevant activity. Although a general framework now exists for labeling cardinal interneuron and motor neuron populations within the ventral spinal cord using Cre-mouse lines, it is apparent that each cardinal spinal neuron population is in fact a complex mixture of many heterogeneous cell types when viewed from the perspective of inputs, outputs, firing properties, and molecular-genetic attributes. Despite clear evidence for this heterogeneity, the relationship between each of these cellular properties is very fragmentary. The goal of Project 3 is to interrelate how cell lineage (cardinal neuron identity), connectivity to motor pools, intrinsic firing properties, and molecular genetics define cell types to provide a true definition of cell identity. This interconnected framework of cell features is critical because it will allow modeling to predict how spinal circuitry modulates the control of movement, and it will serve as the basis for genetic experiments that perturb neuronal function in order to test predictions of the model. This U19 Spinal Cord Circuit Team hypothesizes that the heterogeneity among premotor interneurons will scale with the complexity of motor functions mediated by different motor pools. If this hypothesis is correct, muscle groups controlling the wrist will be controlled by a more diverse population of premotor interneurons than the subset controlling the elbow because the degrees of freedom in movement differ between these two joints. There are two main approaches that will be employed to define interneuron heterogeneity: patch clamp electrophysiology in order to define input/output relationships, and single cell sequencing transcriptomics (scRNAseq) to define molecular heterogeneity. These methods will be anchored to connectivity and lineage by recording and sequencing cells that have been Cre-tagged to mark their lineage of origin (i.e. V1, V2a, V2b, V3) and retrograde trans-synaptically labeled with rabies to identify motor pool connectivity. How will the characterization of cell type-specific intrinsic firing patterns and transcriptome be applied to the broader understanding of neuroscience and limb movements in particular? First, each cardinal interneuron group will be divided into many additional subtypes based on their unique combinatorial patterns of gene expression. However, the goal is not to attempt to fractionate the cardinal interneuron groups into as many subpopulations as possible, rather it is to establish a set of molecular landmarks that can be used to reliably identify and genetically perturb subsets of interneurons with known firing patterns and connectivity. It is only with information about cell numbers, connectivity, synaptic strength, firing properties, and “surgical” molecular tools to perturb neuronal subtype activity can models of cervical spinal circuitry be created and functionally tested to understand how forelimb movements are regulated.

项目3 -细胞表型：内在生理和遗传特征