HCS Screens with Drugs with known activities

Following spinal cord injury, CNS neurons require a permissive environment, rich in growth-promoting cues, for axonal growth, guidance, regeneration and recovery. Neuronal cell adhesion molecules (CAMs) mediate axon growth, branching, fasciculation, guidance and synapse formation. They are essential for proper development of the nervous system, including the corticospinal tract. As different CAMs have distinct structures and functions, the intracellular signaling mechanisms they employ must be distinct as well, yet these differences are poorly understood. Our objective is to elucidate the molecular mechanisms that underlie CAM regulated axon growth and branching; in particular, to characterize the mechanisms stimulated by the L1 immunoglobulin superfamily CAM and compare them to those employed by the calcium-dependent CAM, N-cadherin, and the extracellular matrix protein laminin. We have conducting a "high-content" screen to determine how approximately 500 chemical compounds, which regulate diverse intracellular signaling pathways, affect CAM-mediated neurite initiation, growth and branching. Our chemical library includes compounds from BIOMOL's ICCB Known Bioactives Library as well as compounds that target additional signaling proteins of interest. The screen has been done with mouse cerebellar granule neurons and rat hippocampal neurons grown on CAM and laminin substrates. Early results from this screen demonstrate that manipulating the activities of MAPKs, clathrin and other signaling proteins differentially affects various aspects of neuronal biology such as neurite initiation, growth and branching on CAM and laminin substrates. We are currently focusing on a pathway that regulates branching of hippocampal neurons. This project is being led by Post-Doc Alexis Tapanes-Castillo.