Image analysis tools for quantification of spinal motor neuron subtype identities

Abstract

Discovery of neuronal subtype-specific markers allows for precise identification of molecularly and functionally unique nerve cells in the central nervous system (CNS). High degree of neuronal diversity generally implies that single markers can rarely be used to define individual motor neuron subtypes. As we improve our knowledge of molecular heterogeneity of nerve cells, neuronal quantification increasingly depends on intersectional expression analysis of multiple markers. In the case of spinal cord motor neurons, dozens of motor neuron subtypes can be defined by unique patterns of expression of developmentally regulated transcription factors thus offering a unique opportunity to utilize image analysis approaches for identification and analysis of motor neuron subtype identities. Here, we describe a detailed approach for quantification and analysis of motor neuron subtype identities differentiated from embryonic stem (ES) cells using immunohistochemistry, immunocytochemistry, and Flagship Biosciences image analysis approaches. The discussed approaches simplify and accelerate neuronal subtype quantification and as such should benefit both basic and translational neuroscience research.