A novel inhibitor of p75-neurotrophin receptor improves functional outcomes in two models of traumatic brain injury.

The p75 neurotrophin receptor is important in multiple physiological actions including neuronal survival and neurite outgrowth during development, and after central nervous system injury. We have discovered a novel piperazine-derived compound, EVT901, which interferes with p75 neurotrophin receptor oligomerization through direct interaction with the first cysteine-rich domain of the extracellular region. Using ligand binding assays with cysteine-rich domains-fused p75 neurotrophin receptor, we confirmed that EVT901 interferes with oligomerization of full-length p75 neurotrophin receptor in a dose-dependent manner. Here we report that EVT901 reduces binding of pro-nerve growth factor to p75 neurotrophin receptor, blocks pro-nerve growth factor induced apoptosis in cells expressing p75 neurotrophin receptor, and enhances neurite outgrowth in vitro Furthermore, we demonstrate that EVT901 abrogates p75 neurotrophin receptor signalling by other ligands, such as prion peptide and amyloid-β. To test the efficacy of EVT901 in vivo, we evaluated the outcome in two models of traumatic brain injury. We generated controlled cortical impacts in adult rats. Using unbiased stereological analysis, we found that EVT901 delivered intravenously daily for 1 week after injury, reduced lesion size, protected cortical neurons and oligodendrocytes, and had a positive effect on neurological function. After lateral fluid percussion injury in adult rats, oral treatment with EVT901 reduced neuronal death in the hippocampus and thalamus, reduced long-term cognitive deficits, and reduced the occurrence of post-traumatic seizure activity. Together, these studies provide a new reagent for altering p75 neurotrophin receptor actions after injury and suggest that EVT901 may be useful in treatment of central nervous system trauma and other neurological disorders where p75 neurotrophin receptor signalling is affected

PUMILIO competes with AUF1 to control DICER1 RNA levels and miRNA processing

DICER1 syndrome is a cancer predisposition disorder caused by mutations that disrupt the function of DICER1 in miRNA processing. Studying the molecular, cellular and oncogenic effects of these mutations can reveal novel mechanisms that control cell homeostasis and tumor biology. Here, we conduct the first analysis of pathogenic DICER1 syndrome allele from the DICER1 3 UTR. We find that the DICER1 syndrome allele, rs1252940486, abolishes interaction with the PUMILIO RNA binding protein with the DICER1 3 UTR, resulting in the degradation of the DICER1 mRNA by AUF1. This single mutational event leads to diminished DICER1 mRNA and protein levels, and widespread reprogramming of miRNA networks. The in-depth characterization of the rs1252940486 DICER1 allele, reveals important post-transcriptional regulatory events that control DICER1 levels

Dexmedetomidine modulates neuroinflammation and improves outcome via alpha2-adrenergic receptor signaling after rat spinal cord injury.

BACKGROUND: Spinal cord injury induces inflammatory responses that include the release of cytokines and the recruitment and activation of macrophages and microglia. Neuroinflammation at the lesion site contributes to secondary tissue injury and permanent locomotor dysfunction. Dexmedetomidine (DEX), a highly selective α2-adrenergic receptor agonist, is anti-inflammatory and neuroprotective in both preclinical and clinical trials. We investigated the effect of DEX on the microglial response, and histological and neurological outcomes in a rat model of cervical spinal cord injury. METHODS: Anaesthetised rats underwent unilateral (right) C5 spinal cord contusion (75 kdyne) using an impactor device. The locomotor function, injury size, and inflammatory responses were assessed. The effect of DEX was also studied in a microglial cell culture model. RESULTS: DEX significantly improved the ipsilateral upper-limb motor dysfunction (grooming and paw placement; P<0.0001 and P=0.0012), decreased the injury size (P<0.05), spared white matter (P<0.05), and reduced the number of activated macrophages (P<0.05) at the injury site 4 weeks post-SCI. In DEX-treated rats after injury, tissue RNA expression indicated a significant downregulation of pro-inflammatory markers (e.g. interleukin [IL]-1β, tumour necrosis factor-α, interleukin (IL)-6, and CD11b) and an upregulation of anti-inflammatory and pro-resolving M2 responses (e.g. IL-4, arginase-1, and CD206) (P<0.05). In lipopolysaccharide-stimulated cultured microglia, DEX produced a similar inflammation-modulatory effect as was seen in spinal cord injury. The benefits of DEX on these outcomes were mostly reversed by an α2-adrenergic receptor antagonist. CONCLUSIONS: DEX significantly improves neurological outcomes and decreases tissue damage after spinal cord injury, which is associated with modulation of neuroinflammation and is partially mediated via α2-adrenergic receptor signaling

Controlling the Charge State and Redox Properties of Supported Polyoxometalates via Soft Landing of Mass-Selected Ions

We investigate the controlled deposition of Keggin polyoxometalate (POM) anions, PMo₁₂O₄₀^3– and PMo₁₂O₄₀^2–, onto different self-assembled monolayer (SAM) surfaces via soft landing of mass-selected ions. Utilizing in situ infrared reflection absorption spectroscopy (IRRAS), ex situ cyclic voltammetry (CV), and electronic structure calculations, we examine the structure and charge retention of supported multiply charged POM anions and characterize the redox properties of the modified surfaces. SAMs of alkylthiol (HSAM), perfluorinated alkylthiol (FSAM), and alkylthiol terminated with NH₃⁺ functional groups (NH₃⁺SAM) are chosen as model substrates for soft landing to examine the factors that influence the immobilization and charge retention of multiply charged anionic molecules. The distribution of charge states of POMs on different SAM surfaces is determined by comparing the IRRAS spectra with vibrational spectra calculated using density functional theory. In contrast with the results obtained previously for multiply charged cations, soft-landed anions are found to retain charge on all three SAM surfaces. This charge retention is attributed to the substantial electron binding energy of the POM anions. Investigation of redox properties by CV reveals that while surfaces prepared by soft landing exhibit similar features to those prepared by adsorption of POM from solution, the soft-landed POM^2– has a pronounced shift in oxidation potential compared with POM^3– for one of the redox couples. These results demonstrate that ion soft landing is uniquely suited for precisely controlled preparation of substrates with specific electronic and chemical properties that cannot be achieved using conventional deposition techniques

Dexmedetomidine modulates neuroinflammation and improves outcome via alpha2-adrenergic receptor signaling after rat spinal cord injury.

BACKGROUND:Spinal cord injury induces inflammatory responses that include the release of cytokines and the recruitment and activation of macrophages and microglia. Neuroinflammation at the lesion site contributes to secondary tissue injury and permanent locomotor dysfunction. Dexmedetomidine (DEX), a highly selective α2-adrenergic receptor agonist, is anti-inflammatory and neuroprotective in both preclinical and clinical trials. We investigated the effect of DEX on the microglial response, and histological and neurological outcomes in a rat model of cervical spinal cord injury. METHODS:Anaesthetised rats underwent unilateral (right) C5 spinal cord contusion (75 kdyne) using an impactor device. The locomotor function, injury size, and inflammatory responses were assessed. The effect of DEX was also studied in a microglial cell culture model. RESULTS:DEX significantly improved the ipsilateral upper-limb motor dysfunction (grooming and paw placement; P<0.0001 and P=0.0012), decreased the injury size (P<0.05), spared white matter (P<0.05), and reduced the number of activated macrophages (P<0.05) at the injury site 4 weeks post-SCI. In DEX-treated rats after injury, tissue RNA expression indicated a significant downregulation of pro-inflammatory markers (e.g. interleukin [IL]-1β, tumour necrosis factor-α, interleukin (IL)-6, and CD11b) and an upregulation of anti-inflammatory and pro-resolving M2 responses (e.g. IL-4, arginase-1, and CD206) (P<0.05). In lipopolysaccharide-stimulated cultured microglia, DEX produced a similar inflammation-modulatory effect as was seen in spinal cord injury. The benefits of DEX on these outcomes were mostly reversed by an α2-adrenergic receptor antagonist. CONCLUSIONS:DEX significantly improves neurological outcomes and decreases tissue damage after spinal cord injury, which is associated with modulation of neuroinflammation and is partially mediated via α2-adrenergic receptor signaling

Differential fracture response to traumatic brain injury suggests dominance of neuroinflammatory response in polytrauma.

Polytraumatic injuries, specifically long bone fracture and traumatic brain injury (TBI), frequently occur together. Clinical observation has long held that TBI can accelerate fracture healing, yet the complexity and heterogeneity of these injuries has produced conflicting data with limited information on underlying mechanisms. We developed a murine polytrauma model with TBI and fracture to evaluate healing in a controlled system. Fractures were created both contralateral and ipsilateral to the TBI to test whether differential responses of humoral and/or neuronal systems drove altered healing patterns. Our results show increased bone formation after TBI when injuries occur contralateral to each other, rather than ipsilateral, suggesting a role of the nervous system based on the crossed neuroanatomy of motor and sensory systems. Analysis of the humoral system shows that blood cell counts and inflammatory markers are differentially modulated by polytrauma. A data-driven multivariate analysis integrating all outcome measures showed a distinct pathological state of polytrauma and co-variations between fracture, TBI and systemic markers. Taken together, our results suggest that a contralateral bone fracture and TBI alter the local neuroinflammatory state to accelerate early fracture healing. We believe applying a similar data-driven approach to clinical polytrauma may help to better understand the complicated pathophysiological mechanisms of healing

Differential fracture response to traumatic brain injury suggests dominance of neuroinflammatory response in polytrauma.

Polytraumatic injuries, specifically long bone fracture and traumatic brain injury (TBI), frequently occur together. Clinical observation has long held that TBI can accelerate fracture healing, yet the complexity and heterogeneity of these injuries has produced conflicting data with limited information on underlying mechanisms. We developed a murine polytrauma model with TBI and fracture to evaluate healing in a controlled system. Fractures were created both contralateral and ipsilateral to the TBI to test whether differential responses of humoral and/or neuronal systems drove altered healing patterns. Our results show increased bone formation after TBI when injuries occur contralateral to each other, rather than ipsilateral, suggesting a role of the nervous system based on the crossed neuroanatomy of motor and sensory systems. Analysis of the humoral system shows that blood cell counts and inflammatory markers are differentially modulated by polytrauma. A data-driven multivariate analysis integrating all outcome measures showed a distinct pathological state of polytrauma and co-variations between fracture, TBI and systemic markers. Taken together, our results suggest that a contralateral bone fracture and TBI alter the local neuroinflammatory state to accelerate early fracture healing. We believe applying a similar data-driven approach to clinical polytrauma may help to better understand the complicated pathophysiological mechanisms of healing

Derivation of Multivariate Syndromic Outcome Metrics for Consistent Testing across Multiple Models of Cervical Spinal Cord Injury in Rats

<div><p>Spinal cord injury (SCI) and other neurological disorders involve complex biological and functional changes. Well-characterized preclinical models provide a powerful tool for understanding mechanisms of disease; however managing information produced by experimental models represents a significant challenge for translating findings across research projects and presents a substantial hurdle for translation of novel therapies to humans. In the present work we demonstrate a novel ‘syndromic’ information-processing approach for capitalizing on heterogeneous data from diverse preclinical models of SCI to discover translational outcomes for therapeutic testing. We first built a large, detailed repository of preclinical outcome data from 10 years of basic research on cervical SCI in rats, and then applied multivariate pattern detection techniques to extract features that are conserved across different injury models. We then applied this translational knowledge to derive a data-driven multivariate metric that provides a common ‘ruler’ for comparisons of outcomes across different types of injury (NYU/MASCIS weight drop injuries, Infinite Horizons (IH) injuries, and hemisection injuries). The findings revealed that each individual endpoint provides a different view of the SCI syndrome, and that considering any single outcome measure in isolation provides a misleading, incomplete view of the SCI syndrome. This limitation was overcome by taking a novel multivariate integrative approach for leveraging complex data from preclinical models of neurological disease to identify therapies that target multiple outcomes. We suggest that applying this syndromic approach provides a roadmap for translating therapies for SCI and other complex neurological diseases.</p> </div

Standardized digital locomotor analysis for evaluating recovery after spinal cord injury in rodents.

<p><b><i>A,</i></b> Digital footprint analysis allows objective quantification of many correlated outcomes including: <b><i>B,</i></b> Stride-length for each limb; <b><i>C,</i></b> Print area for each limb; <b><i>D,</i></b> Distribution of limb use reflected as the absolute deviation from the pre-injury baseline (i.e. deviation from ∼25% recruitment for each limb).</p