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Principal Investigator: David Paul Stirling
Organization: UNIVERSITY OF LOUISVILLE
Fiscal Year: 2024
Award: $446,778
Funding agency: National Institute of Neurological Disorders and Stroke
Abstract: Neurological outcome after spinal cord injury (SCI) is dependent on the extent of primary injury and
the delayed secondary degeneration of spared white matter (WM) and grey matter. Although Ca2+ overload is
established as a key mediator of secondary injury, therapeutically targeting external sources of Ca2+ to date
have failed to improve neurological recovery in pre-clinical studies and following human SCI. This proposal will
assess the role of store-operated Ca2+ entry (SOCE) directly in spinal cord neurons and microglia after SCI
using cell type specific knockout of key SOCE mediators. Although, SOCE plays a vital role in maintaining Ca2+
homeostasis and is necessary to sustain intracellular Ca2+ at critical levels for immune cell function, we
propose that aberrant and excessive SOCE causes secondary degeneration of WM. The role of SOCE in WM
injury, microglial activation, and function remains poorly understood. Furthermore, the precise role of the
essential SOCE components including stromal interaction molecule (stim 1 and -2), and Orai 1-3 (form the
Ca2+ channel pore) in microglial function and neuronal injury remains unclear. Our preliminary data support an
important role for SOCE in mediating secondary degeneration, microglial activation and proinflammatory
cytokine release, and worsening neurological recovery. We hypothesize that dysregulation of SOCE mediates
“bystander” secondary axonal degeneration following SCI by increasing Ca2+ permeability through Stim and/or
Orai channels causing Ca2+ overload in axons. In addition, we hypothesize that SOCE regulates microglial
activation and release of proinflammatory factors that negatively impacts neurological recovery after SCI. Our
specific Aims are to, 1. Determine the role of SOCE in secondary degeneration and neurological recovery
following SCI. 2. Determine the role of microglial SOCE in secondary degeneration, wound healing, and
neurological recovery after SCI. To accomplish these aims, we will use two photon excitation intravital imaging
to visualize the dynamic response of spinal cord axons and microglia after SCI in real time. We will use both
pharmacological SOCE inhibitors and cell type specific knockout of key SOCE mediators directly in spinal
neurons and microglia. The most efficacious approach will then be assessed using behavioral testing, amount
of spared WM and grey matter, and wound healing. The technology and approach may help advance the field
as live imaging of axons over time allows unequivocal determination of the fate of injured axons and whether
they can be rescued in real-time with treatment. Furthermore, it allows direct visualization of microglia
simultaneously with axons and their interactions as these events are unfolding in the injured spinal cord. This
proposal is innovative and uses advanced imaging techniques to explore overlooked areas of SCI research.
The approach taken may also unveil novel drug targets and repurpose FDA approved drugs found to inhibit
SOCE (e.g., teriflunomide). The underlying mechanisms of WM injury may also be relevant to other
neurological diseases of the nervous system such as multiple sclerosis, stroke, and TBI.
Terms: <2-photon><Acute><Afferent Neurons><Anti-Inflammatories><Anti-Inflammatory Agents><Anti-inflammatory><Apoplexy><Area><Autoregulation><Axon><Biological Function><Biological Process><Blood><Blood Reticuloendothelial System><Body Tissues><Brain Vascular Accident><Breeding><Calcium><Cell Communication and Signaling><Cell Function><Cell Physiology><Cell Process><Cell Signaling><Cellular Function><Cellular Physiology><Cellular Process><Cerebral Stroke><Cerebrovascular Apoplexy><Cerebrovascular Stroke><Chronic><Cicatrix><Data><Degenerative Neurologic Disorders><Disseminated Sclerosis><Drug Targeting><Drugs><Environment><Event><FDA approved><Generalized Growth><Growth><Growth Agents><Growth Factor><Growth Substances><Histology><Homeostasis><Hortega cell><Human><Image><Imaging Procedures><Imaging Technics><Imaging Techniques><Immune><Immunes><Inflammation Mediators><Inflammatory><Injury><Intracellular Communication and Signaling><KO mice><Knock-out><Knock-out Mice><Knockout><Knockout Mice><LoxP-flanked allele><Mediating><Mediator><Medication><Medulla Spinalis><Mice><Mice Mammals><Microglia><Modern Man><Molecular><Mouse Strains><Multiple Sclerosis><Murine><Mus><Myelogenous><Myeloid><Myeloid Cells><Nerve Cells><Nerve Degeneration><Nerve Unit><Nervous System><Nervous System Degenerative Diseases><Nervous System Diseases><Nervous System Disorder><Neural Cell><Neural Degenerative Diseases><Neural degenerative Disorders><Neurocyte><Neurodegenerative Diseases><Neurodegenerative Disorders><Neurologic Body System><Neurologic Deficit><Neurologic Degenerative Conditions><Neurologic Disorders><Neurologic Organ System><Neurologic outcome><Neurological Disorders><Neurological outcome><Neuron Degeneration><Neuronal Injury><Neurons><Nitrogen><Null Mouse><O element><O2 element><Outcome><Oxygen><Pain><Painful><Pathologic><Pathway interactions><Patients><Permeability><Pharmaceutical Preparations><Phenotype><Physiologic><Physiological><Physiological Homeostasis><Play><Process><Production><Proteins Growth Factors><Recovery><Recovery of Function><Reporter><Reporting><Research><Role><STIM1><STIM1 gene><Scars><Secondary to><Sensory Neurons><Signal Transduction><Signal Transduction Systems><Signaling><Site><Source><Spinal><Spinal Cord><Spinal Cord Trauma><Spinal Trauma><Spinal cord injured><Spinal cord injury><Stroke><Stromal Interaction Molecule 1><Subcellular Process><Technology><Time><Tissue Growth><Tissue Preservation><Tissues><Traumatic Myelopathy><Visualization><Wallerian Degeneration><Wound Repair><axon damage><axon injury><axonal damage><axonal degeneration><axonal injury><behavior test><behavioral test><biological signal transduction><brain attack><cell type><cerebral vascular accident><cerebrovascular accident><cytokine><cytotoxic><degenerative axon><degenerative diseases of motor and sensory neurons><degenerative neurological diseases><drug repositioning><drug repurposing><drug/agent><effective therapy><effective treatment><experiment><experimental research><experimental study><experiments><floxed><floxed allele><functional improvement><functional outcomes><functional recovery><gitter cell><glial activation><glial cell activation><gray matter><imaging><improve function><improved><improved functional outcomes><in vivo><inflammatory mediator><inhibitor><injuries><innovate><innovation><innovative><insular sclerosis><intra-vital imaging><intra-vital microscopy><intravital imaging><intravital microscopy><mesoglia><microglial cell><microgliocyte><neural degeneration><neural inflammation><neurodegeneration><neurodegenerative><neurodegenerative illness><neuroinflammation><neuroinflammatory><neurological degeneration><neurological disease><neurological recovery><neuron injury><neuronal><neuronal degeneration><neuroprotection><neuroprotective><new drug target><new druggable target><new pharmacotherapy target><new therapeutic target><new therapy target><novel><novel drug target><novel druggable target><novel pharmacotherapy target><novel therapeutic target><novel therapy target><ontogeny><pathway><perivascular glial cell><pharmacologic><pre-clinical study><preclinical study><prevent><preventing><recruit><repurposing agent><repurposing medication><response><secondary degeneration><social role><stroked><strokes><substantia alba><substantia grisea><therapeutic target><two-photon><white matter><white matter injury><wound healing><wound recovery><wound resolution>