Biology subjects

Plautz, E. J.

Publications and source records attributed to Plautz, E. J..

2 recordsLinked to original sources

bioRxiv2025

Uncovering a new player in ischemic stroke: a study of intra-arterial interferon-gamma-producing monocytes in hyperacute stroke

Stroke triggers a rapid and complex immune response that is not yet fully understood, especially within hours after an ischemic infarct. Our previous study in stroke patients revealed a significant increase in interferon- gamma (IFN-{gamma}) immediately (hyperacute) and downstream of the ischemic ictus, within the arterial compartment. The present study investigated the source, inciting factors, and role of IFN-{gamma} in a preclinical murine model. Stroke was produced using transient middle cerebral artery occlusion, and immune cells within the arterial vasculature distal to the occlusion (pre- and post-occlusion) were characterized using flow cytometry. Compared with the control samples, the post-occlusion samples presented an increase in IFN-{gamma}+ and CD69+ cells, whereas no significant increase was detected in IL17+, IL4+, and CD25+ cells. Further analysis of the IFN-{gamma}+ population revealed two novel attributes. First, interrogation of the identity of these IFN-{gamma}+ cells revealed that the increase in IFN-{gamma} production was largely driven by CD14+ cells in the post- occlusion sample, with negligible contributions from other canonical IFN-{gamma}-producing cells (CD4, CD8). Second, the IFN-{gamma}+ cells exhibited two distinct clusters, an IFN-{gamma}low and an IFN-{gamma}hi population. Further analysis revealed that the IFN-{gamma} low population was largely composed of CD14+ cells, whereas the IFN-{gamma}hi population was dominated by CD4+ T-cells. To explore the conditions driving IFN-{gamma} production, an in vitro ischemia model involving oxygen-glucose deprivation (OGD) was employed. Co-culturing of naive splenocytes with OGD-treated CNS cells and OGD-derived supernatant resulted in a significant increase in IFN-{gamma}+CD14+ cells, as compared to normoxic controls, an effect that coincided with marked loss of DAPI+ and NeuN+DAPI+ cells in mixed cortical (neuronal and glial) cultures. In summary, this study identified intra-arterial CD14+ monocytes as novel early sources of IFN-{gamma} in the hyperacute phase of stroke, a role traditionally attributed to adaptive immune cells. Using in vivo and in vitro ischemia models, the findings reveal that injury-associated signals from CNS cells are sufficient to directly induce IFN-{gamma} production in CD14+ cells, redefining early stroke immunopathology and uncovering a potential target for timely immunomodulation.

immunology↗

bioRxiv2024

SpinalTRAQ: A novel volumetric cervical spinal cord atlas identifies the corticospinal tract synaptic projectome in healthy and post-stroke mice

Abstract/SummaryDescending corticospinal tract (CST) connections to the neurons of the cervical spinal cord are vital for performance of forelimb-specific fine motor skills. In rodents, CST axons are almost entirely crossed at the level of the medullary decussation. While specific contralateral axon projections have been well-characterized using anatomic and molecular approaches, the field currently lacks a cohesive imaging modality allowing rapid quantitative assessment of the entire, bilateral cervical cord projectome at the level of individual laminae and cervical levels. This is potentially important as the CST is known to undergo marked structural remodeling in development, injury, and disease. We developed SpinalTRAQ (Spinal cord Tomographic Registration and Automated Quantification), a novel volumetric cervical spinal cord atlas and machine learning-driven microscopy acquisition and analysis pipeline that uses serial two-photon tomography-images to generate unbiased, region-specific quantification of the fluorescent pixels of anterograde AAV-labeled CST pre-synaptic terminals. In adult mice, the CST synaptic projectome densely innervates the contralateral hemicord, particularly in laminae 5 and 7, with sparse, monosynaptic input to motoneurons in lamina 9. Motor pools supplying axial musculature in the upper cervical cord are bilaterally innervated. The remainder of the ipsilateral cord has sparse labeling in a distinct distribution compared to the contralateral side. Following a focal stroke of the motor cortex, there is a complete loss of descending corticospinal axons from the injured side. Consistent with prior reports of axon collateralization, the CST spinal projectome increases at four weeks post-stroke and continues to elevate by six weeks post stroke. At six weeks post-stroke, we observed striking synapse formation in the denervated hemicord from the uninjured CST in a homotopic distribution. Additionally, CST synaptic reinnervation increases in the denervated lamina 9 in nearly all motoneuron pools, exhibiting novel patterns of connectivity. Detailed level- and lamina-specific quantification of the bilateral cervical spinal cord synaptic projectome reveals previously undescribed patterns of CST connectivity in health and injury-related plasticity.

neuroscience↗