Experimental Neurology

Spinal cord injury (SCI) pathology is highly difficult to treat due to substantial heterogeneity in injury presentation and spread, along with unclear mechanisms linking damage to pathology. Damages from injury forces (primary injury) are exacerbated by a series of biochemical events that follow the initial damage and injure additional tissue, known as secondary injury. Reactive aldehydes, such as acrolein, play a key role in propagating secondary injury cascades following SCI. Targeting acrolein after SCI has demonstrated therapeutic potential in limiting injury spread and pathology. However, injury mechanisms linking reactive aldehydes to SCI outcome have not been fully characterized. To gain a more comprehensive understanding of the cellular and molecular mechanisms underlying SCI, we generated proteomic profiles of rat spinal cords 24 h (acute phase) after subjection to SCI, sham injury, saline injection, or acrolein injection. We performed gene set enrichment analysis (GSEA) to characterize proteins and pathways significantly enriched after SCI and acrolein-injection. We then used Translatable Components Regression (TransComp-R), a framework for translating biological signatures across systems, to assess whether acrolein-associated spinal cord signatures can stratify SCI from sham outcomes. Our proteomics analysis revealed 467 differentially expressed proteins (DEPs) between the sham and SCI groups and 7 DEPs between saline and acrolein injection groups. Notably, the complement and coagulation cascades were upregulated in spinal cords subjected to SCI and acrolein injection. Our TransComp-R analysis further demonstrated that acrolein-associated signatures could distinguish SCI from sham conditions. Taken together, our findings suggest that acrolein induces proteomic alterations during the acute phase of SCI and is associated with complement and coagulation cascade activation, among other pathways. Therefore, this study reinforces the notion that understanding the role of acrolein in the acute phase of secondary SCI may be beneficial.

Cervical spinal cord injury (SCI) frequently leads to life-threatening respiratory insufficiency by disrupting descending phrenic pathways. There is growing interest in non-invasive neuromodulatory approaches to enhance plasticity of spared respiratory circuits. We investigated whether cervical repetitive magnetic stimulation (rMS) applied to the injured cervical spinal cord promotes ventilatory recovery in a preclinical mouse model. Adult mice received a unilateral C3 hemicontusion followed by either rMS or sham stimulation. We found that rMS-treated mice significantly improved recovery of tidal volume and minute ventilation at 21 days post injury(dpi) compared to sham controls under various breathing conditions (isoflurane anesthesia, poikilocapnic phase and hypercapnic challenge). Correspondingly, diaphragm EMG enhanced ipsilateral hemidiaphragm activity in ventral and medial regions, and even contralateral hemidiaphragm activity in its ventral part. This was associated with a marked attenuation of the inflammatory response at the cervical spinal cord level. Indeed, rMS lowered astroglial, fibrotic scarring, pro-inflammatory CD68-, Iba1- microglial/macrophage markers. Moreover, perineuronal net expression (WFA positive staining) is globally reduced in the ventral spinal horn, whereas at the lesion site it is markedly increased and tightly wrapped around motoneurons. Together, these findings demonstrate that rMS promotes functional respiratory recovery after cervical SCI through combined enhancement of diaphragmatic motor output and modulation of the inflammatory and extracellular environment. Together, these functional and cellular findings indicate that spinal rMS promotes a permissive, pro-regenerative environment supporting respiratory circuit plasticity. We conclude that rMS significantly enhances ventilatory recovery via reduced inflammatory response and improved intraspinal rewiring after high cervical SCI, suggesting it is a promising non-invasive strategy. The ability of rMS to engage spared respiratory networks and support neuroplasticity highlights its promise as a safe, non-invasive therapeutic strategy with translational potential for rehabilitation of breathing function after SCI. One Sentence SummaryNoninvasive cervical magnetic stimulation improves breathing after spinal cord injury by boosting diaphragm activity and reducing inflammation.

Traumatic brain injury (TBI) triggers complex and evolving secondary cascades that disrupt mitochondrial homeostasis and contribute to progressive neurodegeneration. Although mitochondrial impairment is a well-recognized driver of post-traumatic pathology, the spatial and temporal progression of mitochondrial dysfunction, particularly in regions distal to the injury site, remains poorly defined, and potential sex-specific responses remain understudied. Here, we performed a comprehensive mitochondrial-focused analysis in a mouse model of controlled cortical impact (CCI), quantifying mtDNA copy number (mtDNA-CN), mitochondrial gene expression, and protein markers regulating biogenesis, transcription, electron transport chain integrity, and mitophagy. Mitochondrial profiles were assessed across four brain regions (cortex at 2, 4, and 6 mm from the injury epicenter, and hippocampus) at four time points (6h, 12h, 24h, and 48h) in both female and male C57BL/6J mice. While mtDNA content exhibited only modest and region-restricted reduction, particularly near the injury core, transcriptional and protein-level changes were far more pronounced and sex-divergent. Females displayed extensive early cortical gene activation followed by widespread hippocampal suppression at 48 h across mitochondrial dynamics, OXPHOS, transcriptional regulation, and biogenesis pathways, accompanied by 48h in PGC-1, TFAM, and NDUFS1. In contrast, males showed minimal transcriptional disruption but demonstrated delayed compensatory increases in TFAM, NDUFS1, and p62 protein levels, suggesting activation of mitochondrial maintenance and recovery programs. These spatially and temporally distinct responses reveal fundamental sex-specific vulnerabilities in mitochondrial regulation after TBI. Together, our findings provide a direction to an integrated mitochondrial landscape of early post-injury events and identifies critical windows and pathways that may support sex-specific therapeutic targeting to restore mitochondrial function after TBI.

PurposeTo determine whether spatial decomposition of longitudinal retinal nerve fiber layer (RNFL) change maps reveals distinct modes of glaucomatous progression masked by conventional averaging, and to validate these modes through structure-function mapping and genetic association analysis. MethodsPixel-wise RNFL rates of change were computed from longitudinal optic disc OCT scans of 15,242 eyes (8,419 adults with primary open-angle glaucoma [POAG]; Massachusetts Eye and Ear, 1998-2023). A loss-only constraint zeroed all thickening values, reflecting the biological prior that adult RNFL does not regenerate. Non-negative matrix factorization decomposed these maps into spatial progression components (80% training set). Components were evaluated in a held-out set (20%) for retinotopic structure-function concordance, visual field (VF) progressor classification against global and quadrant RNFL rates, and enrichment of genetic association signals at established POAG loci. ResultsSix anatomically distinct progression patterns emerged, including diffuse circumferential loss, focal peripapillary defects, and arcuate bundle degeneration. Pattern-based models significantly outperformed global RNFL rate for classifying VF progressors (area under the curve, 0.750 [95% CI, 0.709-0.790] vs. 0.702; P = .0096) and explained additional variance in functional decline (Nagelkerke pseudo-R{superscript 2}, 0.301 vs. 0.198; P = .0011). Structure-function mapping confirmed retinotopic coherence. Spatial phenotypes recovered stronger genetic signals than global rates at 85.3% of established POAG loci, suggesting they capture more biologically homogeneous endophenotypes of progression. ConclusionsGlaucomatous structural progression occurs through spatially distinct modes with independent structure-function and genetic signatures that conventional RNFL averaging obscures.

BackgroundSpinal cord injury (SCI) triggers persistent neuroinflammation, gliosis, neuronal loss, and demyelination, leading to motor deficits and neuropathic pain. Botulinum neurotoxin type A (BoNT/A) has shown anti-inflammatory and neuroprotective effects in acute SCI, but its potential in the chronic phase remains unclear. This study investigates whether combining BoNT/A with electrical muscle stimulation (EMS) enhances recovery in chronic SCI. MethodsAdult mice with severe thoracic SCI (paraplegic) underwent EMS (30 min/day for 10 non-consecutive days starting 3 days post-injury) or no stimulation. Fifteen days after SCI, animals received a single intrathecal injection of BoNT/A (15 pg/5 L) or saline. Functional recovery was assessed up to 60 days as well as in moderate and mild SCI mice, neuropathic pain onset and maintenance were evaluated. Spinal cord tissue was analysed for astrocytic and microglial morphology, neuronal and oligodendroglia survival, myelin protein expression, and in vitro effects on oligodendrocyte precursor cells (OPCs). The phenotype of hindlimb muscles was evaluated through morphological and gene expression analyses. ResultsEMS was able to counteract muscle atrophy and fibrosis, and when combined with BoNT/A, also denervation. Moreover, the combination restored hindlimb motor function in chronic SCI, whereas BoNT/A or EMS alone were ineffective. Neuropathic pain, a common comorbidity associated with SCI, was mitigated by BoNT/A treatment even when administered in the chronic phase. BoNT/A reduced astrocytic hypertrophy and excitatory synapse association and was associated with a morphology-based redistribution of microglial profiles toward a resting-like classification, decreased apoptosis, and increased neuronal and oligodendroglia survival. Myelin basic protein expression was significantly elevated in vivo. In vitro, BoNT/A promoted OPC differentiation into myelinating oligodendrocytes, increased process complexity, and upregulated Myelin basic protein, galactocerebroside C, proteolipid protein, and myelin oligodendrocyte glycoprotein under both proliferative and differentiating conditions. Cleaved SNAP25 colocalization with OPC confirmed direct BoNT/A internalization and activity. ConclusionsBoNT/A exerts multi-cellular neuroprotective actions in chronic SCI, supporting neuronal and oligodendroglia survival, reducing neuroinflammation, enhancing remyelination and the combination with EMS promotes substantial recovery of muscle homeostasis within a permissive microenvironment shaped by early stimulation. Its efficacy depends on a permissive microenvironment achieved through EMS. These results provide strong rationale for the clinical evaluation of BoNT/A as a therapeutic strategy for chronic SCI.

Hypoxic-ischemic (HI) brain injury in neonates is one of the leading causes of lifelong neurological disability. Behavioral tests in preclinical rodent models are widely used to assess motor and cognitive outcomes after HI injury; however, these assays usually depend on subjective and labor-intensive manual scoring. Recent advances in markerless pose estimation offer new opportunities for automated and reproducible behavioral quantification in animal and infant recordings, but their use in neonatal HI preclinical studies remains limited. Wistar rat pups underwent HI injury using the Rice-Vannucci model at postnatal day 7 (P7). Three developmental behavioral tests included righting reflex (P8), negative geotaxis (P14), and wire hang (P16), were recorded and analyzed by both a human rater and an automated pipeline using DeepLabCut (DLC), an open source markerless pose estimation framework. Automated measurements were compared with manual scores using Intraclass Correlation Coefficients (ICC), Bland-Altman analysis, and Pearson correlation. DLC-derived measurements demonstrated strong agreement with manual scoring across all assays. ICC values were 0.929 (95% CI 0.648-0.971) for righting reflex, 0.965 (0.888-0.989) for negative geotaxis, and 0.958 (0.876-0.985) for wire hang. An automated behavioral analysis framework integrating DLC-based pose estimation with rule based quantification and supervised machine learning offers a reliable and objective alternative to manual scoring in neonatal HI models, enabling more efficient and reproducible behavioral assessment.

BackgroundGlobal cerebral anoxia is a leading cause of death and resuscitated patients often remained persistently affected by neurological deficits. While previous studies suggest that brain-heart electrophysiological interactions may predict severity and prognosis after hypoxic brain injury coma, little is known about the brain-heart dynamics at near-death. Gaining insight into these mechanisms is crucial for developing targeted interventions in critical conditions. ResultsUsing a rodent model of reversible systemic anoxia (n=29, male and female rats), we investigated whether brain-heart interactions during the asphyxia onset could predict the return of brain electrical activities after resuscitation. Electrophysiological recordings confirmed that cerebral activity declines following asphyxia, coinciding with increased heart rate variability. Notably, the strong coupling between cardiac parasympathetic activity and high-frequency brain activity in the somatosensory cortex and hippocampus serves as a key predictor of a favorable outcome. ConclusionOur study underscores the involvement of the brain-heart axis mechanisms in the physiology of dying and the potential prognostic significance of these mechanisms, paving the way for translational research into critical care, based on new characterizations of cardiac reflexes and brain-heart interactions.

Post-stroke inflammation contributes to poor outcomes in both clinical and experimental studies. Interleukin-6 (IL-6) is a key inflammatory mediator in ischemic stroke, and higher circulating IL-6 levels are associated with greater stroke severity and worse clinical outcomes. Targeting IL-6 signaling therefore represents a potential therapeutic strategy. We tested whether inhibition of IL-6 signaling with the IL-6 receptor (IL-6R) blocking antibody tocilizumab (TCZ) improves recovery after experimental stroke. Aged mice (18-20 months) underwent 60 minutes of middle cerebral artery occlusion. TCZ (20 mg/kg) was administered 5 hours after ischemia onset, and behavioral outcomes were assessed weekly for 5 weeks. Delayed TCZ treatment improved long-term functional recovery in aged male mice but not in aged females. To explore this difference, we measured circulating soluble IL-6R (sIL-6R) levels in mice and patients with ischemic stroke. Females exhibited significantly higher post-stroke sIL-6R levels. Increasing the TCZ dose to 100 mg/kg restored efficacy in aged female mice and improved long-term outcomes. These findings support a role for IL-6R pathway modulation in improving recovery after experimental stroke and suggest that therapeutic response may differ by sex and target availability, potentially related to differences in circulating sIL-6R after ischemic injury.

BackgroundSpinal cord injury (SCI) triggers remote pathological changes in supraspinal regions, including neuroendocrine dysfunction that manifests clinically as hyponatremia and central diabetes insipidus. Clinical observations of lesion-level dependency and sequential transformation between these disorders suggest a temporally ordered hypothalamic cascade in which a compensatory arginine vasopressin (AVP)-driven neuroendocrine surge may precede a later neuroinflammation and endoplasmic reticulum (ER) stress-mediated neuronal exhaustion. Direct transcriptomic evidence for the temporal ordering of these events, however, has been lacking. MethodsWe performed a dual-cohort transcriptomic analysis. A discovery cohort (NCBI Sequence Read Archive PRJNA953752) comprised hypothalamic tissue from adult male Sprague-Dawley rats subjected to high-thoracic (T3) SCI, low-thoracic (T10) SCI, or sham surgery, sampled at post-injury day 7 and analyzed with edgeR/DESeq2 (|log2FC| > 1, Padj < 0.05). An independent chronic-phase validation cohort (Gene Expression Omnibus GSE297887) of hippocampal tissue from SCI and sham mice was interrogated as a sensitive supraspinal proxy for remote neuroinflammatory and ER-stress signatures. Pre-defined gene panels covered neuroendocrine, neuroinflammation, and ER-stress/unfolded-protein-response categories. ResultsIn the discovery cohort, high-thoracic SCI produced a lesion-level-dependent neuroendocrine surge in the hypothalamus: Avp (fold change 7.23; Padj = 0.002), Oxt (fold change 14.25; Padj = 2.3 x 10-7), and Ucn3 (fold change 9.22; Padj = 0.002) were among the most significantly upregulated genes genome-wide, whereas low-thoracic SCI failed to reach significance for any of these targets. Classical neuroinflammation markers and canonical ER-stress effectors remained transcriptionally silent (all Padj > 0.69). The PERK-pathway sentinel genes Trib3 and Ppp1r15a/GADD34 exhibited coordinated sub-threshold trends indicative of early activation, and Avp expression was tightly correlated with Mmp9 (r = 0.833; P = 0.0004). In the chronic-phase validation cohort, microglial P2ry12 and ferroptosis signatures were significantly upregulated (P2ry12 fold change 1.33; P = 0.008) suggesting a primed microglial state, while ER-stress effectors remained silent. ConclusionsThese data support a temporally ordered hypothalamic cascade after SCI in which an early compensatory neuroendocrine surge precedes -- and may precipitate, through biosynthetic overload and blood-brain-barrier disruption -- a subsequent neuroinflammation and ER-stress crisis. The defined molecular window between neuroendocrine activation and inflammatory/ER-stress engagement identifies a candidate therapeutic window for early neuroprotective intervention in acute SCI.

After cervical spinal cord injury (cSCI), swallowing dysfunction is common and increases mortality via aspiration pneumonia. While these deficits have often been attributed to secondary damage from complications of injury management, there has recently been a greater appreciation for the modulatory role of spinal populations in swallow generation that are disrupted by injury. Here, we illustrate in a rodent model of cSCI that epidural spinal stimulation (ESS) of the phrenic motor nucleus at spinal segment C4 alters motor output at the hypoglossal motor nucleus through activation of excitatory ascending spinal pathways and inhibitory peripheral sensory feedback mechanisms. These findings highlight the importance of spinal-brainstem communication in shaping the motor program of swallow-related musculature and offer the potential for stimulation of the cervical spinal cord to be a therapeutic target for restoring swallowing function after injury. NEW & NOTEWORTHYIn two varying severity models of spinal cord injury, we demonstrate the effects of spinal cord stimulation at C4 on the distal hypoglossal motor nucleus. We show that despite being anatomically distant, electrical stimulation of the phrenic motor nucleus increases hypoglossal motor output through ascending spinal pathways and dampens it through peripheral pathways. These findings highlight the importance of spinal-brainstem communication and illustrate the ability of spinal stimulation to restore this communication after injury.

Traumatic brain injury (TBI) is a condition of high incidence worldwide, but remains mostly undertreated. Previous observations in preclinical studies pointed to a beneficial effect of insulin-like growth factor 1 (IGF-1) in TBI. As brain injury is associated to loss of IGF-1 sensitivity, we tested the therapeutic potential of AIK3a305 (AIK3), a novel IGF-1 sensitizer. Twenty-four hours after mild TBI induced by controlled impact, mice received daily intraperitoneal injections of AIK3 during 4 weeks. We found that TBI-associated sensorimotor disturbances measured with the adhesive-removal test were reverted by AIK3 treatment. In addition, neurological and cognitive disturbances measured by the neurological severity score and Y maze respectively, were also ameliorated by treatment with the IGF-1 sensitizer, whereas increased anxiety after mild TBI was also normalized by AIK3. Circulating levels of IGF-1 were increased after AIK3 treatment in TBI mice, while serum IL-6 levels, a biomarker of inflammation associated to TBI were similar to control mice treated with AIK3. Transcriptomic analysis determined that treatment with AIK3 widely affected gene expression in TBI brains, showing a general reduction in both up- and down-regulated genes. Collectively, these data support the use of IGF-1 sensitizers such as AIK3 for treatment of TBI.

Repeated exposure to hypoxia (oxygen levels below sea-level atmospheric conditions, [~]21%) alternated with regular voluntary exercise, known colloquially as Living High, Training Low, or simply High-Low, is used by elite athletes to boost exercise benefits and athletic performance. While paradigms of High-Low training have been utilized by Olympic athletes for decades, the therapeutic potential of a High-Low regimen in the context of neurotrauma has yet to be investigated. This long-term experiment evaluated the independent and combined effects of repeated hypoxic exposure and voluntary exercise on functional outcomes within the context of preclinical spinal cord injury (SCI). We hypothesized that combinatorial High-Low training enhances functional recovery, beyond either exercise or repeated exposures to hypoxia alone, to improve outcomes after SCI. Adult female rats (n=62) underwent a high-cervical hemisection (LC2H) to model spinal cord injury. At 6 weeks post-SCI, treatment (access to exercise wheel, repeated exposure to normobaric hypoxia at rest, or alternation of both) began in the surviving subjects (n=49). Despite initiation of treatment beyond the acute post-injury phase, High-Low therapy significantly improved respiratory function and prevented the development of SCI-associated anxiety-like behaviors. Notably, repeated in vivo exposure to normobaric hypoxia induced a shift in peripheral T cell profiles, characterized by increased CD4+ and reduced CD8+ expression. These findings indicate that combining repeated exposure to hypoxia with voluntary exercise as a therapy could promote recovery in the existing spinal cord-injured population. Collectively, this work provides a foundational first step for further investigation of High-Low training as a rehabilitation therapy for individuals living with SCI.

Open-angle glaucoma (OAG) affects approximately 57.5 million individuals worldwide and is characterized by the progressive loss of retinal ganglion cells (RGC) and irreversible optic nerve damage resulting from chronic ocular hypertension. Intraocular pressure (IOP) is the only major modifiable risk factor in OAG and clinical treatments necessarily aim to lower IOP in order to preserve RGCs and prevent vison loss. Pharmacological therapies, such as prostaglandin analog containing eye drops, are known to be effective at reducing IOP, but are critically undermined by poor patient compliance and are unable to control for potentially damaging diurnal fluctuations in IOP, leading to vision loss even in patients diagnosed early. Herein we evaluate the effectiveness of a long-acting, single use, prostaglandin-based recombinant adeno-associated virus (rAAV)-mediated IOP-lowering gene therapy treatment in glaucomatous DBA/2J mice and demonstrate that sustained IOP reduction leads to preservation of both optic nerve anatomy and function in end-stage glaucomatous disease. One Sentence SummaryIOP-lowering gene therapy provides partial anatomical and functional rescue in glaucomatous mouse model following single dose treatment

BackgroundPeri-synaptic astrocyte processes (PAPs) play a fundamental role in synapse formation and function. Central afferent synapse loss and astrocyte dysfunction greatly impede sensory-motor circuitry in spinal muscular atrophy (SMA) disease progression, however mechanisms underpinning tripartite synapse dysfunction remains to be fully elucidated. The aims of this study were to further define PAP and motor neuron synaptic defects in human SMA disease pathology and implement a therapeutic intervention strategy to improve motor neuron function. MethodsWe derived astrocyte monocultures and motor neuron astrocyte co-cultures from healthy and SMA patient induced pluripotent stem cell (iPSC) lines to assess intrinsic astrocyte filopodia defects and phenotypes occurring at the synapse-PAP interface, respectively, using cell surface capture mass spectrometry proteomics, confocal and super resolution microscopy, synaptogliosome isolation, and electrophysiology. ResultsSMA astrocytes demonstrated intrinsic filopodia actin defects featuring low abundance of actin-associated cell surface N-glycoproteins, and decreased filopodia density and CDC42-GTP levels after actin remodeling stimulation. This phenotype is likely driven by the significant reduction of CD44 and phosphorylated ezrin, radixin and moesin ERM proteins (pERM) within SMA astrocyte filopodia. The dual combination of SMN1 gene therapy and forskolin treatment, an adenylyl cyclase activator leading to increased cyclic adenosine monophosphate (cAMP) levels and actin signaling pathway stimulation, led to extensive branching and increased filopodia density of SMA astrocytes during actin remodeling. SMA patient-derived motor neuron and astrocyte co-cultures, particularly samples derived from male patient iPSC lines, demonstrated a significant decrease in synapse number, actin-associated pre-synaptic neurotransmitter release protein, synapsin I (SYN1), and PAP-associated expression of pERM and glutamate transporter, EAAT1. Our astrocyte-targeted SMN1 augmentation and forskolin treatment paradigm restored SYN1 protein levels within the SMA synaptogliosome, resulting in significant increases in motor neuron synapse formation and function, but did not fully restore PAP-associated proteins levels at the synapse. ConclusionsSMA astrocytes demonstrate intrinsic actin-associated defects within filopodia, which correlates with decreased pERM levels at tripartite motor neuron synapses. We also define a SMN- and cAMP-targeted treatment paradigm that significantly increases pre-synaptic neurotransmitter release protein levels to improved SMA motor neuron synapse formation and function. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=117 SRC="FIGDIR/small/714618v1_ufig1.gif" ALT="Figure 1"> View larger version (44K): org.highwire.dtl.DTLVardef@1257ab8org.highwire.dtl.DTLVardef@19c0010org.highwire.dtl.DTLVardef@c84552org.highwire.dtl.DTLVardef@3f1e62_HPS_FORMAT_FIGEXP M_FIG C_FIG

Purinergic 2X7 receptor (P2X7R) is considered to play a critical role in neurological diseases, including epilepsy, and has also been proposed as a potential marker for neuroinflammation. This study aimed to validate the binding properties of the novel P2X7R radiotracer, [3H]JNJ-64413739, in rat brain using in vitro autoradiography, and additionally to explore spatial and temporal changes in P2X7R binding levels in a rat model of temporal lobe epilepsy using intrahippocampal administration of kainic acid (KA). Saturation of [3H]JNJ-64413739 to brain sections yielded a KD of approximately 3 nM, with full saturation around 10 nM. The radiotracer was displaced with a structurally different P2X7R ligand, JNJ-47965567, indicating high affinity and specificity to rat P2X7R. In post epileptic rats, region-specific [3H]JNJ-64413739 binding revealed a bilateral increase in the hippocampal formation and its subregions few days after status epilepticus, peaking at day 30, and remained stable at this high level until day 90. Similar temporal profiles were identified in subcortical regions such as the thalamus. Interestingly, no change in binding was observed in the temporal and piriform cortices until day 30 where a dramatic increase occurred. Also, in the corpus callosum, significant increase was detected 30 days after the seizure. These results show that P2X7R binding, likely reflecting inflammation, is increased at delayed time points and exhibit region-specific patterns that is different from acute effects. Our findings suggest that P2X7R may contribute to sustained neuroinflammation and may be involved in those changes leading to epileptogenesis and the development of chronic epilepsy. Highlights[3H]JNJ-64413739 binds specifically to the purinergic P2X7 receptor (P2X7R) and saturates in the rat brain. P2X7R binding increases in a region- and time-dependent manner following status epilepticus. P2X7R binding remains elevated during chronic epilepsy in all examined brain regions. P2X7R is considered a link between early seizures and sustained neuroinflammation and epileptogenesis.

Temporal lobe epilepsy (TLE) is a heterogeneous disorder with most clinical presentations involving unilateral or bilateral hippocampal seizure onsets. Antiseizure medications are often ineffective for TLE, and epilepsy surgery can have variable outcomes. Risk factors for TLE are readily identifiable and typically precede chronic epilepsy, providing a window of opportunity for preventative treatments. However, there are currently no clinically approved anti-epileptogenic therapies. In this study, we investigate the role of Wnt signaling in epileptogenesis using two mouse TLE models, the intrahippocampal kainate model of unilateral TLE (IHK), and the intraperitoneal kainate model of bilateral TLE (IPK). We specifically examined adult-born immature dentate granule cells as these cells have been heavily implicated in the pathogenesis of TLE and clinical TLE is typically initiated in adulthood. We observed that adult-born immature dentate granule cells undergo pathological morphological changes during epileptogenesis in both the IHK and IPK models of TLE. When compared across epileptogenic zones, however, these changes differed between the two models. Wnt signaling also decreased in these cells in epileptic mice during the epileptogenic period. When mice were treated with SB415286, a highly selective Wnt activator, Wnt signaling in immature dentate granule cells was restored to baseline levels and pathological remodeling changes were reduced in both models. These data therefore suggest that a reduction in Wnt signaling in immature dentate granule cells plays an etiological role in epileptogenesis, and that restoring Wnt signaling using Wnt activating drugs or alternative agents may have therapeutic potential as an anti-epileptogenic strategy in TLE.

Temporal lobe epilepsy (TLE) is a complex neurological disorder characterized by spontaneous recurrent seizures and its underlying mechanism remains elusive. This study aimed to investigate the role of cystine-knot AMPAR modulating protein 44 (CKAMP44) in the pathological process of TLE and its potential as a therapeutic target using kainic acid (KA)-induced epilepsy mouse model of TLE. Our results showed that CKAMP44 protein and mRNA expression was significantly increased and primarily localized to neurons during the chronic phase of TLE. Nkx2-1 regulated the transcription of CKAMP44 in the hippocampus brain tissues of KA-induced TLE mice. Inhibition of CKAMP44 suppressed seizure susceptibility and severity in the KA-induced epilepsy mice via behavioral and local field potential monitoring. Furthermore, inhibition of CKAMP44 decreased frequency and amplitudes of spontaneous excitatory postsynaptic currents indicating that the excitatory synaptic transmission was reduced in an in vitro epilepsy model. Mechanistically, inhibition of CKAMP44 specifically upregulated the membrane surface expression of GluA1 and the phosphorylation level of GluA1-ser831 by downregulating protein phosphatase 3 regulatory subunit B(PPP3r2) expression. Overexpression of PPP3r2 downregulated the phosphorylation level and surface expression of GluA1, which ultimately exacerbated the seizure activity suppressed by CKAMP44 knockdown. Collectively, our results indicate that CKAMP44 may be a potential therapeutic target for the treatment of TLE.

Ischemic stroke triggers a cascade of molecular and cellular processes leading to fibrotic scar formation, entailing activation of brain platelet-derived growth factor receptor (PDGFR){beta}+ cells. Kruppel-like factor (KLF)4 plays an important role in regulating the activation of peripheral PDGFR{beta}+ perivascular cells in response to hypoxia/ischemia. Herein, we aimed to characterize the spatiotemporal responses of brain PDGFR{beta}+ cells while assessing the contribution of KLF4. This was achieved using transgenic mice that enable tracking or conditionally depleting KLF4 in PDGFR{beta}+ cells, which were subjected to experimental ischemic stroke. Next, we employed point pattern analysis (PPA) and topological data analysis (TDA) to quantitatively characterize cell phenotypic changes and spatial distribution over injury progression after ischemic stroke. We show that brain PDGFR{beta}+ cells rapidly become reactive and early localize to regions prone to irreversible damage. We report the emergence of parenchymal PDGFR{beta}+ cells, which cannot be causally linked to proliferation or vascular detachment. Moreover, our analysis reveals that KLF4 is barely expressed in brain PDGFR{beta}+ cells under normal conditions, and that its expression is slightly induced in reactive cells in the injured brain. Notably, specific attenuation of KLF4 induced expression in PDGFR{beta}+ cells does not affect cell reactivity and spatiotemporal distribution, nor scar formation and injury severity. These observations suggest that in contrast with the periphery, KLF4 is not implicated in regulating the responses of brain PDGFR{beta}+ cells. Our results indicate that the reactivity of brain PDGFR{beta}+ cells after stroke is spatiotemporally diverse, evolve over injury progression, and is distinct from peripheral perivascular cells. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=65 SRC="FIGDIR/small/712632v1_ufig1.gif" ALT="Figure 1"> View larger version (26K): org.highwire.dtl.DTLVardef@1149c62org.highwire.dtl.DTLVardef@26edaaorg.highwire.dtl.DTLVardef@1bd3d35org.highwire.dtl.DTLVardef@fd8030_HPS_FORMAT_FIGEXP M_FIG C_FIG

Sudden unexpected death in Epilepsy (SUDEP) is the leading cause of death in patients with Epilepsy. Although SUDEP results from cardiorespiratory arrest, its underlying mechanisms are poorly understood. Considering the significant association between stress-related disorders and Epilepsy, we hypothesized that stress exaggerates autonomic reflexes critical in cardiorespiratory function and that these exaggerated reflexes increase susceptibility to SUDEP. Experiments were performed using a novel mouse model of SUDEP where chronic hyperactivity of central corticotropin-releasing hormone (CRH) neurons (Kcc2/Crh) predisposes mice to SUDEP in the weeks following seizure induction based on the ventral intrahippocampal kainate (vIHKA) model of chronic Epilepsy. In our study, the vIHKA model was employed in both wild-type (WT) and Kcc2/Crh mice while they were monitored with EEG and ECG using in vivo telemetry and underwent terminal autonomic reflex testing at time points when mortality peaked and plateaued. A resting tachycardia developed by one week following vIHKA injection but subsided by day 30 in both WT and Kcc2/Crh mice. During spontaneous seizures, Kcc2/Crh mice had more pronounced reflex-like ictal bradycardias compared to WT controls that notably occurred prior ([~]10 sec) to seizure termination. vIHKA injection promoted time-dependent exaggeration of autonomic reflexes, with Kcc2/Crh mice exhibiting robust autonomic disturbances compared to WT controls, including a pronounced serotonin-mediated Bezold Jarisch reflex. Taken together, our findings indicate that increased autonomic disturbance burden parallels time-dependent SUDEP susceptibility in mice with hyperactive stress circuits.

BackgroundNeonatal global hypoxic-ischemic cerebral injury is a leading cause of infant mortality and lifelong disability. Current rodent models do not replicate neonatal global cerebral ischemia (nGCI) and reperfusion injury. Here, we developed and characterized a rodent model of cardiac arrest and cardiopulmonary reperfusion (CA/CPR) to induce nGCI, producing acute systemic ischemia, mild neuronal injury, white matter alterations, and motor and memory deficits. MethodsRat pups underwent CA/CPR or sham procedure on postnatal day 9-11. CA/CPR in rat pups was performed under anesthesia while intubated. Asystole was induced with intravenous (IV) KCl and maintained for 10-14 minutes. Resuscitation included oxygen ventilation, chest compressions, and IV epinephrine. ResultsTwelve minutes of asystole provided an optimal balance between survival and systemic injury. Behavioral testing on postoperative day (POD) 7 revealed memory impairments. Despite the absence of overt neuronal death in the hippocampus or cerebellum, we observed evidence of glial activation and white matter alterations. ConclusionThis novel rodent model of nGCI addresses limitations in existing models while offering clinically relevant features to support future mechanistic and translational research. ImpactO_LIThis study validates cardiac arrest and cardiopulmonary resuscitation (CA/CPR) as a novel model for neonatal global cerebral ischemia (nGCI), complementing existing rodent models of unilateral and permanent injury by enabling investigation of both global ischemia and reperfusion injury. C_LIO_LInGCI results in memory impairment in the absence of overt neuronal cell death. Functional deficits are associated with neuroinflammatory responses in the hippocampus, white matter, and cerebellum. C_LIO_LINeonatal CA/CPR induces global cerebral ischemia which uniquely allows investigation of hindbrain structures, such as cerebellum, which are typically spared in existing rodent models of neonatal hypoxia-ischemia. C_LI