Neurotherapeutics

In this randomized, double-blind, controlled trial of 8 weeks of repetitive transcranial magnetic stimulation (rTMS) for chronic pain, we compared the classic primary motor cortex (M1) rTMS with a novel target-selection strategy based on pre-therapy cortical connectivity. Guided by principles of homeostatic plasticity, we tested whether stimulating the cortical site with the lowest pre-therapy global connectivity would be more effective than two active comparators: stimulating the site with the highest pre-therapy global connectivity or stimulating M1 independent of connectivity. Before starting rTMS treatment, TMS-evoked EEG potentials were recorded from four cortical targets: M1, the dorsolateral prefrontal cortex, the anterior cingulate cortex, and the posterosuperior insular cortex. For each target, global connectivity was quantified using a distance-weighted, phase-based index (debiased weighted phase lag index, wPLI) derived from pre- and post-TMS-evoked EEG activity, capturing both the magnitude and spatial extent of TMS-induced oscillatory phase locking across cortical regions. Target allocation in the Low- and High-Connectivity groups was based on this global connectivity measure. Ninety patients with chronic pain were randomized to Low-Connectivity, High-Connectivity, or Classic-M1 groups. Treatment consisted of 12 rTMS sessions delivered over 8 weeks to the assigned target. The primary outcome was the proportion of patients achieving [≥] 30% reduction in pain intensity. Secondary outcomes included continuous change in pain intensity, pain interference, sleep, fatigue, mood, quality of life, and patient global impression of change. No between-group differences were observed for primary or secondary outcomes (p > 0.05). In prespecified exploratory analyses, we examined whether pre-therapy local connectivity (within-target wPLI) predicted treatment response. In the Classic-M1 group, lower pre-therapy local M1 connectivity was associated with a greater reduction in pain intensity (r = 0.50, p = 0.005). This association was not observed in the Low- or High-Connectivity groups. A regression model including group-by-connectivity interaction indicated that the relationship between local connectivity and pain reduction differed between the Classic-M1 and High-Connectivity groups (p = 0.038). The results of this clinical trial showed that connectivity-based target allocation using global connectivity did not improve clinical outcomes. However, lower local M1 connectivity was associated with greater pain reduction following Classic-M1 stimulation, suggesting that local M1 connectivity may serve as a potential biomarker of response.

Neuropathic pain (NP) affects approximately 60% of individuals with spinal cord injury (SCI). Existing pharmacological treatments provide only modest relief and are often limited by adverse effects, while non-pharmacological options show small effects at best. As such, there remains a need for accessible, mechanism-informed treatments for SCI-NP. This protocol describes a trial evaluating two promising home-based neuromodulatory interventions for SCI-NP - electroencephalography neurofeedback (EEG-NF) and transcranial direct current stimulation (tDCS) - tested both independently and when applied in combination. We will employ a partially double-blinded (i.e. 1 treatment blinded, the other not), 2x2 factorial randomised controlled trial. Adults with chronic SCI-NP (N=192) will be randomised to: (1) EEG-NF + active tDCS, (2) EEG-NF + sham tDCS, (3) active tDCS alone, or (4) sham tDCS alone, in addition to treatment as usual. Participants will complete 20 home-based sessions over 5 weeks. The primary outcome is change in overall pain severity with the primary endpoint being 6 weeks post-randomisation, with secondary endpoints at 16, 26 and 52 weeks post-randomisation. Secondary outcomes (worst pain intensity, pain interference, sleep, depressive symptoms, health-related quality of life) will be assessed at 6 weeks, 16 weeks, 26 weeks and 52 weeks post-randomisation. This will be the first large-scale trial of home-based EEG-NF and tDCS for SCI-NP. If found to be effective, these scalable interventions could be integrated into routine care and inform further optimisation of neuromodulation strategies for managing SCI-NP.

Parkinsons disease (PD) is the second most common neurodegenerative disease, resulting from accumulation of -synuclein (-syn) in midbrain dopaminergic neurons and progressive neuronal loss. The most relevant species of -syn, oligomers, may exert neurotoxicity in a variety of mechanisms. Accumulation of misfolded -syn in the endoplasmic reticulum (ER) lumen induces ER stress conditions that leads to activation of the Unfolded Protein Response (UPR) and its main sensor PKR-like ER kinase (PERK). PERK is critical for cell fate determination - under prolonged ER stress, it may direct cell towards pro-apoptotic pathways. Targeting of -syn aggregation or UPR by genetic and pharmacological approaches proved effective in preclinical models of PD by previous research. Thus, in the present study, we aimed to determine the potential effect of combination of small-molecule inhibitors of -syn aggregation and ER stress-mediated PERK signaling (namely anle138b and AMG44) in a novel, 3D in vitro model of PD. We demonstrate that combination of both anti-aggregation and ER stress-targeting approaches amplifies neuroprotection against PD in organoid model in terms of increased neuronal metabolic activity, decreased -syn phosphorylation and aggregation, reduced dopaminergic cell death, and restoration of proteostasis.

Manganese neurotoxicity, arising from environmental overexposure or inherited transporter disorders due to pathogenic variants in SLC30A10 and SLC39A14, leads to manganism, a debilitating Parkinsonian movement disorder. Alhtough chelation therapy can partially reverse neuropathology, current clinical practice relies on intravenous CaNa2EDTA, which is burdensome and poorly suited for long-term use. Consequently, there remains a significant unmet need for more effective, orally bioavailable chelators. This study aimed to establish and validate a pipeline for identifying and assessing novel ligands that attenuate manganese neurotoxicity and support preclinical translational development. Based on the structural features of manganese-based MRI contrast agents, we selected two chelators, N-picolyl-N,N',N'-trans-1,2-cyclohexylenediaminetriacetic acid (H3PyC3A) and ethylenediaminetetraacetic acid-benzothiazole aniline (H4EDTA-BTA), and their methyl ester derivatives, Me3PyC3A and Me4EDTA-BTA. These were evaluated in vivo using zebrafish (slc39a14U801/U801) and mouse (Slc30a10KO/KO) models of manganese overload. H3PyC3A and Me3PyC3A demonstrated greater manganese-mobilizing efficacy than CaNa2EDTA, improving locomotor behavior in slc39a14U801/U801 zebrafish. In Slc30a10KO/KO mice, intravenous administration confirmed selective in vivo chelation of excess manganese over physiological concentrations of zinc and copper. Although oral bioavailability was low (<1%), long-term oral administration of H3PyC3A modestly reduced liver and brain Mn accumulation, suggesting an added benefit of oral administration via gastrointestinal chelation. This integrated in vitro to in vivo pipeline provides a robust and scaleable approach for the development of next-generation Mn chelators. Slc39a14U801 loss-of-function zebrafish enable high throughput identification of candidate compounds while Slc30a10KO/KO mice offer a clinically relevant disease model for pharmacokinetic profiling and proof-of-concept validation.

Background: Chronic pain affects millions of patients globally and remains therapeutically chal-lenging. While conventional pharmacological approaches have limitations and side effects, pulsed electromagnetic field (PEMF) therapy represents a non-invasive biophysical approach. However, the biological mechanisms underlying PEMF efficacy remain poorly understood. Objective: This study starting from a multi-center post-market surveillance (PMS) data of 81 patients treated with Synth&eacuteXer (a CE-marked Class IIa PEMF device) proposes a mechanistic framework that links ob- served clinical effects to epigenetic modulation via the histone demethylase KDM6B. Materials and Methods: Patients with inflammatory and degenerative disorders causing chronic pain were treated with Synth&eacuteXer across four Italian rehabilitation centers. Pain was assessed using the Numerical Pain Rating Scale (NPRS) before and after treatment. Statistical analysis included descriptive statistics, ANOVA, correlations, and Cohen d effect size. Proposed mechanisms were based on and extrapolated from molecular and biochemical studies demonstrating KDM6B-dependent epigenetic changes in response to specific PEMF sequences. Results: Mean NPRS score decreased significantly from 8.07 {+/-} 1.65 (PRE) to 1.79 {+/-} 1.67 (POST), representing a 6.28-point reduction (p < 0.001; Cohen d = 3.1). Ninety-eight percent of patients showed pain reduction [&ge;] 2 points. No adverse effects were reported. Subset analysis revealed consistent responses across inflammatory (n=19) and degenerative (n=62) pathologies. Discussion: While the observational nature of these data precludes definitive causal attribution, the magnitude of clinical response combined with emerging evidence of KDM6B-mediated epigenetic remodeling suggests a plausible biological basis for PEMF efficacy. Specifically, sequence-depend- ent electromagnetic stimulation may promote the production of and release of anti-inflammatory cytokines and pain resolution through histone demethylation and chromatin remodeling ultimately acting on the expression modulation of such regulatory cytokines. Conclusions: These post-market surveillance data provide clinical evidence of PEMF effects in chronic pain management. The proposed epigenetic mechanism, while requiring further experimental validation and mechanistic confirmation, offers a science-based framework for understanding PEMF biological action and guiding future investigations.

Background-Synuclein (-Syn) plays a central role in Parkinsons disease (PD). Under pathological conditions, -Syn aggregates into toxic oligomers and fibrils that act as damage-associated molecular patterns (DAMPs), stimulating microglial reactivity. This -Syn-microglia axis creates a self-perpetuating cycle of neuroinflammation and neurodegeneration, accelerating dopaminergic neuron loss in the substantia nigra pars compacta (SNpc) and contributing to motor deficits. Moreover, -Syn pathology spreads through the brain, disrupting synaptic plasticity in cognitive regions like the cortex and hippocampus, leading to early cognitive decline. Thus, targeting -Syn aggregation and its inflammatory consequences presents a promising dual-hit therapeutic strategy for PD. MethodsThis study investigates the therapeutic potential of 3-monothiopomalidomide (3MP), a novel thalidomide derivative designed to reduce neuroinflammation with a potentially better safety profile than Pomalidomide (POM). The neuroprotective and anti-inflammatory effects of 3MP were evaluated in rat primary mesencephalic mixed neuron-microglia cultures exposed to human -Syn oligomers (H-SynOs). Anti-aggregation activity was assessed via Thioflavin T (ThT) assays and Thioflavin S (ThS) staining in SH-SY5Y cells. Finally, the anti-aggregation, anti-inflammatory, and neuroprotective effects of 3MP were evaluated in vivo in a rat model of PD induced by intracerebral infusion of H-SynOs. ResultsIn primary cell cultures, 3MP dose-dependently reduced -Syn-induced neuronal death and microglial inflammatory responses. It also significantly inhibited -Syn aggregation in vitro in the ThT assay and in SH-SY5Y cells exposed to -Syn protofibrils, outperforming POM. When chronically administered in vivo, 3MP preserved dopaminergic neurons within the SNpc and yielded functional benefits on motor and cognitive readouts. Notably, 3MP markedly attenuated -Syn aggregates induced by the H-SynOs infusion in the SNpc more efficiently than POM, as shown by reduced intraneuronal staining for pSer129--Syn+ and reduced pSer129-Syn in both cytoplasmic and phagolysosomal compartments of microglia. In addition, mesencephalic and cortical inflammatory microgliosis that followed to intranigral H-SynOs-infusion, were significantly dampened by 3MP. ConclusionsOverall, 3MP emerges as a dual-action drug candidate capable of modulating neuroinflammation and -Syn aggregation and thereby disrupting the -Syn-driven inflammatory cycle. Its neuroprotective effects and favourable safety profile support its potential as a disease-modifying therapy for PD, with promising implications for clinical translation.

IntroductionThe exploration of alternative strategies for neural tissue regeneration and repair is giving rise to a novel paradigm in neurosurgery: fusogenic therapy. This approach promises rapid restoration of peripheral nerve and spinal cord function by circumventing Wallerian degeneration and eliminating the delay associated with axonal regrowth. Its potential stems from the capacity of fusogens to induce axonal fusion and achieve immediate membrane sealing, complemented by their pronounced neuroprotective properties. However, experimental data on fusogens and their effects are inconsistent, often contentious, and derived using heterogeneous methodologies. MethodsWe present the first comprehensive systematic review covering nearly four decades of research on fusogens for axonal membrane repair and 26 years of their experimental and clinical application in mammalian and human models for peripheral and central nervous system restoration. The review includes a meta-analysis of fusogen efficacy following traumatic spinal cord and peripheral nerve injuries. ResultsConducted in accordance with the PRISMA 2020 flow protocol and PICO criteria, our analysis incorporates 86 sources, 20 of which were included in the meta-analysis. DiscussionIn summary, we have systematized the prevailing approaches and methods for fusogen application, delineated key contentious issues, and identified promising directions for the development of axonal fusion technology.

Parkinsons disease (PD) is the second most progressive degenerative disorder of the brain due to dopaminergic (DA) neuron degenerations and alpha-synuclein (-Syn) accumulations. At present, the disease has no effective treatment. Therefore, the current study objective is to identify a novel anti-PD formula (Zhi-Shi-Huang-Wu Formula, F-2) computed at 8:4:2:1 ratio from HSP 70 promoter activators Valeriana jatamansi (V), Acori talarinowii (A), Scutellaria baicalensis (S), Fructus Schisandrae (F). Traditionally, V is used to cure memory impairments, A treats mental disorders, and chronic mild stress, S for neuroprotection, and F showed multiple therapeutic actions to treat insomnia. This study investigated the neuroprotective potential of the V, A, S, F, formula F-2 and its underlying molecular mechanisms in transgenic Caenorhabditis elegans models. A, S, F, and F-2 successfully restored 6-hydroxydopamine intoxicated DA neuron degenerations, reduced food-sensing behavior disabilities, and attenuated -Syn aggregations. Moreover, activates the lipid deposition and proteasome expressions to confirm -Syn degradations at the cellular level. Reactive oxygen species (ROS) cause oxidative stress, and A, S, F, and F-2 repressed ROS and raised SOD-3 expressions. Overall, these data indicate that V, A, S, F combined into F-2 (22.3%) are more effective against PD progression-like symptom than individual drugs V (0.7%), A (11.4%), S (9.6%), and F (12.6%). These improved neuroprotective actions of F-2 possibly due to following the antioxidative pathway. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=144 SRC="FIGDIR/small/709540v1_ufig1.gif" ALT="Figure 1"> View larger version (47K): org.highwire.dtl.DTLVardef@1a6f1f7org.highwire.dtl.DTLVardef@157a270org.highwire.dtl.DTLVardef@69a238org.highwire.dtl.DTLVardef@1194b5e_HPS_FORMAT_FIGEXP M_FIG C_FIG

Temporal lobe epilepsy (TLE) has an unmet need for precision treatments targeting the seizure focus while avoiding effects on other body parts to minimise side effects. Photopharmacology could enable precision treatment by combining systemic administration of a photoswitchable drug with implantation of an optic fibre in the epileptic focus to induce light-dependent drug conversion from an inactive to an active configuration that interacts with its target receptor to suppress seizures. The photoswitchable {Delta}9-tetrahydrocannabinol ({Delta}9-THC) derivative, azo-THC-3, transitions from an inactive trans to an active cis configuration upon UV irradiation. We demonstrate that local or systemic administration of azo-THC-3 and local UV irradiation in the hippocampus supresses difficult-to-treat seizures in the intrahippocampal kainic acid mouse model of TLE. Furthermore, our findings illustrate that the photoswitch strategy avoids hypolocomotion, a common side effect of systemic {Delta}9-THC administration. As such, we provide the first demonstration of seizure suppression with the systemic administration of a photoswitchable compound and its local photoactivation in the seizure focus. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=133 SRC="FIGDIR/small/720358v1_ufig1.gif" ALT="Figure 1"> View larger version (41K): org.highwire.dtl.DTLVardef@1e42794org.highwire.dtl.DTLVardef@1e26891org.highwire.dtl.DTLVardef@13f2b6forg.highwire.dtl.DTLVardef@3c8e48_HPS_FORMAT_FIGEXP M_FIG C_FIG

Chronic low back pain (CLBP) is persistent and refractory, affecting 20-30% of population worldwide. Neurofeedback has been explored as a potential non-pharmacological intervention for chronic pain, although evidence in CLBP remains limited. This study evaluated PainWaive, a consumer-grade digitally-delivered neurofeedback intervention targeting multiple pain-related frequency bands recorded over the sensorimotor cortex in individuals with CLBP. In a multiple-baseline experimental design, four participants completed daily assessments of pain severity and pain interference during randomly-assigned baseline phases of 7, 10, 14, and 20 days, followed by 20 sessions of the PainWaive intervention over four weeks. Daily pain assessments continued during the post-intervention and follow-up phases. Participants rated PainWaive's usability and acceptability at post-intervention. Anxiety, depression, wellbeing, and sleep disturbance were assessed at three timepoints. Aggregated Tau-U analyses indicated a large effect (-0.67) on pain severity from baseline to intervention and very large from baseline to post-intervention (-0.92) and follow-up (-0.92) phases. Large effects (-0.63, -0.62, and -0.70) were also observed for pain interference. Individual-level analyses showed significant reductions across all participants, with visual inspection confirming progressive decreases over time. The intervention was rated usable and acceptable by all participants, while psychological outcomes were mixed and varied across participants. The findings provide promising evidence that the PainWaive neurofeedback intervention may reduce pain severity and pain interference in some individuals with CLBP. By prioritising accessibility, usability, and self-administration, PainWaive supports a foundation for more patient-centred, technology-enabled approaches to chronic pain management. Further evaluation of this approach in randomised trials is required to establish efficacy.

ObjectiveTo conduct de novo meta-analyses quantifying the association of five biopsychosocial risk factor domains with chronic pain or related treatment outcomes, and to construct a composite risk index with formal uncertainty propagation for interventional pain medicine. MethodsUmbrella review with de novo random-effects meta-analyses (DerSimonian-Laird and REML with Knapp-Hartung adjustment) across PubMed/MEDLINE, Scopus, and the Cochrane Library through March 2026. Five risk factor domains were evaluated: (1) sleep disturbance, (2) pain catastrophizing, (3) metabolic/obesity, (4) preoperative opioid exposure, and (5) benzodiazepine co-prescription. Publication bias was assessed via Eggers test and PET-PEESE regression. Primary study overlap was quantified using the Corrected Covered Area (CCA). We constructed a primary three-domain composite (sleep, catastrophizing, metabolic) and a secondary expanded six-domain composite (adding opioid, BZD, smoking), using the logistic link function with binary risk factor inputs (present/absent); composite score 95% confidence intervals were computed via delta method variance propagation. Risk of bias of the composite was assessed using PROBAST [Wolff RF et al., Ann Intern Med 2019]; TRIPOD+AI compliance is reported in Supplementary S6 [Collins GS et al., BMJ 2024]. Reviewer process (per registered protocol PROSPERO CRD420261360881): screening, data extraction, risk-of-bias assessment (AMSTAR-2/PROBAST/ROBINS-I), and GRADE certainty rating are conducted independently by at least two reviewers -- SPM (confirmed co-reviewer, registered in PROSPERO) as primary rater, with an external third reviewer to be identified and confirmed prior to peer-reviewed submission; JAD acts as guarantor and does not perform primary review tasks. All quantitative outputs reported here are preliminary estimates pending completion of the external third-reviewer audit; a triple-validated version will be posted as a subsequent preprint update before peer-reviewed submission. ResultsAdopted odds ratios: sleep disturbance 1.39 (95% CI 1.21-1.59; k=16; I{superscript 2}=51%), pain catastrophizing 2.10 (1.49-2.95; k=8; I{superscript 2}=0%), metabolic/obesity 1.43 (1.28-1.60; k=33), preoperative opioid exposure 5.32 (2.94-9.64; k=33; I{superscript 2}=99.96%; outcome: prolonged opioid use), and BZD co-prescription 1.77 (1.31-2.39; k=27; outcome: persistent opioid use). REML/Knapp-Hartung estimates produced wider confidence intervals for all loops (opioid: 1.87-15.13). PET-PEESE analysis suggested no substantial small-study effects for the sleep or catastrophizing loops. CCA=3.2% (slight overlap). Primary three-domain composite (sleep + catastrophizing + metabolic): delta method 95% confidence intervals for the composite score spanned 10-15 percentage points; PROBAST risk of bias: moderate. Secondary expanded six-domain composite (adding opioid, BZD, smoking): confidence intervals spanned 12-18 percentage points, crossing risk tier boundaries in moderate-risk patients; PROBAST risk of bias: high (driven by outcome heterogeneity in pharmacological domains). ConclusionsFive biopsychosocial risk factor domains are independently associated with chronic pain or related treatment outcomes. The PALF composite index is presented as a structured analytical framework for future prospective validation, not as a deployable clinical tool. The primary three-domain composite (sleep, catastrophizing, metabolic) achieves outcome homogeneity at the cost of reduced domain coverage; the expanded six-domain composite encompasses the pharmacological burden at the cost of outcome heterogeneity. Both composites carry wide confidence intervals that preclude clinical application without individual patient data validation. No claim to clinical validity is made in the absence of prospective individual-patient-data validation.

The synaptic vesicle glycoprotein 2C (SV2C) is a synaptic protein involved in the regulation of dopamine release. It is expressed in striatum, globus pallidus and substantia nigra, regions involved in the regulation of motor function. Genome-wide association studies, animal model and human brain tissue data indicate a strong link between SV2C and Parkinso[n]s disease, suggesting a potential role of SV2C as synaptic marker for Parkinso[n]s disease. We hypothesize that a positron emission tomography (PET) radioligand for SV2C can serve as imaging marker for Parkinso[n]s disease, enabling early diagnosis and assessment of disease progression. This study was therefore designed to develop a PET radioligand for imaging SV2C. UCB-1A was the lead candidate selected from a library of compounds developed by UCB BioPharma. A translational approach was used, including autoradiography and in vitro binding studies with [3H]UCB-1A, and in vivo PET studies with [11C]UCB-1A in non-human primates (NHPs). The KD of [3H]UCB-1A for rat and human SV2C ranged between 6 and 15 nM, with >100-fold selectivity towards SV2A and SV2B. Specific binding of [3H]UCB-1A in rat and NHP brains was observed in substantia nigra, globus pallidus, striatum and brainstem nuclei, consistent with the expression of SV2C, and was decreased in the striatum of 6-hydroxydopamine-lesioned rats and in the putamen of Parkinson donors. UCB-1A was successfully radiolabelled with 11C and PET studies in NHPs demonstrated that [11C]UCB-1A displays suitable pharmacokinetic properties, a brain distribution consistent with the expression of SV2C and is selective for SV2C. [11C]UCB-1A is the first PET radioligand for in vivo imaging of SV2C and a potential synaptic marker for in vivo studies in Parkinso[n]s disease.

Aggregates of misfolded -synuclein (Syn) and neuroinflammation are pathological features of Parkinsons disease (PD). These, misfolded conformations of Syn promote cytokine and chemokine signaling in the surrounding microenvironment by triggering activation of glial cells through pattern recognition receptors. Microglia and astrocytes act as innate mediators of the neuroimmune response in the brain by regulating inflammatory signaling via paracrine and autocrine forms of cell communication. Extracellular vesicles (EVs) represent a form of glial cell to cell communication that can regulate the glial neuroimmune responses depending on the phenotype of the donor cell. Research has shown that the contents of EVs can be altered via pharmacologically altering the donor cell which offers a potential avenue for the regulation of inflammation. As such, we analyzed enriched mouse cortical primary astrocytes and characterized their response to Syn exposure in the absence and presence of microglia-derived EVs. Using trans-resveratrol, a naturally occurring polyphenol implicated for its anti-inflammatory properties, as our pharmacological agent to generate an anti-inflammatory microglial-derived EV phenotype we found that EVs derived from resveratrol-treated microglia decreased the production of proinflammatory molecules in enriched astrocytes exposed to Syn. Sequencing of EV miRNAs revealed two miRNAs (miR-5099 and miR-115) with significant up-regulation in resveratrol EVs compared to control EVs. Astrocytes transfected with corresponding miRNA mimics prior to Syn exposure showed a dramatic decrease in inflammatory biomarker production. These findings show that microglia-derived EVs and their specific miRNA cargo can attenuate Syn-directed inflammation in astrocytes and may serve as a novel therapeutic for proteinopathies like PD.

Serotonergic psychedelics have attracted considerable interest as promising therapeutic agents. However, the molecular mechanisms linking their acute hallucinogenic-like effects to longer-lasting neuroplastic responses remain incompletely understood, partly because of the scarcity of native neural models suitable for mechanistic studies. Here, we developed a neural stem cell-derived in vitro model capable of differentiating into neuronal and glial lineages and, after characterization, used it to investigate the molecular pharmacology of serotonergic psychedelics. A panel comprising tryptamines, phenethylamines and ergolines, including psychedelic compounds and selected non-psychedelic analogues, was evaluated alongside ketamine and TrkB agonists. Endpoints included dendritogenesis, synaptogenesis, immediate-early gene induction, BDNF expression and lactate production. TrkB silencing abolished dendritogenic responses to serotonergic psychedelics, ketamine and TrkB agonists, whereas 5-HT2A receptor silencing selectively impaired serotonergic psychedelic-induced plasticity and altered TrkB-dependent responses. Most serotonergic compounds also increased synaptogenesis and induced c-Fos and Egr-2 expression, although ligand-specific differences were evident, particularly for psilocin and the phenethylamines DOI and Ariadne. Uncoupling of Gq/11 or Gi/o protein-dependent signaling differentially modified neuroplastic and transcriptional responses, indicating a ligand and endpoint dependent contribution of both pathways. Serotonergic psychedelics further induced a 5-HT2A receptor dependent lactate response that was generally sensitive to disruption of either Gq/11 or Gi/o protein coupling. Taken together, these findings support a model in which serotonergic psychedelics recruit an integrated 5-HT2A-TrkB signaling network with distinct structural, transcriptional and metabolic outputs, and establish this neural stem cell-derived system as a valuable platform for screening and dissecting the signaling basis of psychedelic action.

Huntingtons disease (HD) is a progressive neurodegenerative disease caused by a mutation in the exon 1 of the huntingtin (HTT) gene, which leads to an extended polyglutamine (polyQ) tract in the mutant protein. As a result, mutant huntingtin (mHTT) exon 1 fragments aggregate in cells, which disrupts proper neuronal function and eventually induces cell death. The selective reduction of these toxic mHTT fragments without disturbing the wild-type full-length HTT function would be a potential therapeutic strategy to treat and prevent HD. Intracellular antibodies (intrabodies) have emerged as an attractive strategy to specifically target disease-related proteins, with VHH intrabodies being of high interest as they are much smaller than single-chain variable fragments (scFv). Here, we describe the identification and development of VHH 1 as a lead candidate intrabody targeting the first 17 amino acids of the mHTT protein, using a humanized VHH page-display library to screen against mHTT(Q46) exon 1 to identify potential binders. Next, we further optimized VHH 1 into VHH 1a to improve cytoplasmic solubility. Using immortalized mouse striatal cells that express inducible untagged mHTT exon 1 fragments, we investigated the effects of the intrabody on soluble and insoluble mHTT species via microscopy and biochemical assays. We showed that the VHH 1a intrabody reduces the levels of insoluble mHTT species, thereby effectively interrupting the aggregation process. This study highlights the potential for VHH intrabodies to specifically target mHTT fragments, enabling therapeutic strategies to delay and prevent HD pathology. HighlightsO_LIThree binders were down-selected from a phage-display library to bind HTT N17 C_LIO_LIVHH 1a intrabody is the most efficient at reducing mutant HTT exon 1 aggregation C_LIO_LIVHH 1a acts on soluble HTT exon 1 oligomers to block the transition to inclusion body C_LI

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.

Objective: To quantify the effect size of four biopsychosocial amplifier loops on chronic pain outcomes through systematic review and meta-analysis, and to develop a logistic regression-based risk stratification tool for interventional pain medicine. Methods: We searched PubMed, Scopus, and Cochrane Library through March 2026 for studies reporting adjusted odds ratios for associations between (1) sleep disturbance, (2) pain catastrophizing, (3) metabolic/inflammatory markers, (4) preoperative opioid use/polypharmacy, and chronic pain chronification or treatment failure. Random-effects meta-analyses (DerSimonian-Laird) were performed for each loop. Effect sizes were translated into a composite logistic regression model, the Pain Amplifier Loop Framework (PALF), using ln(OR) as first-order coefficient approximations. Results: Forty-four studies with over 500,000 participants were included. Pooled odds ratios were: sleep disturbance OR=1.80 (95% CI 1.65-1.96; k=16), pain catastrophizing OR=2.11 (95% CI 1.71-2.61; k=8), metabolic/fat mass OR=2.02 (95% CI 1.32-3.09; k=7), preoperative opioid use OR=4.48 (95% CI 2.87-6.97; k=6), and opioid-benzodiazepine co-prescription OR=2.62 (95% CI 1.76-3.89; k=7). All four loops converge on TLR4/NF-kB microglial signaling. The PALF model produces a probability of interventional failure enabling stratification into low, moderate, and high risk categories. Conclusions: Four amplifier loops independently increase chronic pain risk. The PALF provides a transparent, clinically actionable risk score requiring prospective validation.

Background: Psychedelics are emerging as potential management options for chronic musculoskeletal pain due to preliminary evidence of effectiveness and low addictive potential, but patients perceptions remain unknown. This study assessed patient perceptions regarding psilocybin for musculoskeletal pain. Methods: We conducted a cross-sectional survey of adults ([&ge;]19) with musculoskeletal pain attending a hospital-based orthopaedic clinic. Participants reported demographics, perceptions of psychedelics for pain management, and willingness to participate in psychedelic research. Multivariable regression explored factors associated with perceived analgesic potential, and willingness to try a full therapeutic dose of psilocybin or a microdose. Results: Among 295 participants, 73% reported moderate-to-severe pain; 75% used analgesics; of these, 41% used opioids (86/209). While 24% reported prior psychedelic use, only 3% had discussed psychedelics with a healthcare provider. Most perceived that psilocybin had moderate-to-high effectiveness for pain (76%). Most respondents endorsed a moderate-to-high willingness to try microdoses (58%) and macrodoses (53%) of psilocybin for pain. Prior non-therapeutic psychedelic use predicted a 1.05-unit increase in perceived analgesic potential on the 10-point scale (p=.013). Willingness to try a macrodose of psilocybin was most strongly associated with prior non-therapeutic (B=3.16) and therapeutic (B=2.42) psychedelic use; in contrast, pain severity had a significant but modest association, with a 0.21-point increase in willingness for every 1-unit increase in pain severity (p=.017). Similarly, willingness to try a microdose of psilocybin was predicted by non-therapeutic (B=2.82) and therapeutic (B=2.48) use, whereas the effects of pain severity (B=0.20) and younger age (B=-0.30) were significant but small. Most respondents (52%) reported moderate-to-high willingness to participate in a trial of psilocybin for pain relief, and health risks were the primary concern (33%). Conclusions: Study findings suggest a majority hold neutral-to-positive perceptions of psilocybin for pain. Addressing perceived barriers, including health effects and gaps in patient knowledge, should be considered when designing future trials.

The hippocampus is essential for memory consolidation, a process mediated by high-frequency oscillations known as ripples during non-rapid eye movement (NREM) sleep. Ramelteon, a selective MT1/MT2 receptor agonist, has been reported to possess cognitive-enhancing properties; however, its impact on the fine-scale dynamics of hippocampal ripples remains unclear. We performed chronic local field potential recordings from the dorsal hippocampus and prefrontal cortex in mice. Following the intraperitoneal administration of either vehicle or ramelteon, we evaluated sleep architecture and characterized ripple properties, including occurrence rate, amplitude, instantaneous frequency, and duration during NREM sleep. Ramelteon administration significantly increased NREM sleep occupancy. Notably, we found that ramelteon significantly enhanced both the occurrence rate and amplitude of hippocampal ripples compared to the control group. While a slight increase in intra-ripple frequency was observed, other structural features, such as ripple duration and asymmetry index, remained unaffected. Our findings demonstrate that ramelteon facilitates hippocampal ripple dynamics by increasing their occurrence and synchrony during NREM sleep. Given the critical role of ripples in memory consolidation, these neurophysiological changes may underlie the procognitive effects of ramelteon. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=55 SRC="FIGDIR/small/723673v1_ufig1.gif" ALT="Figure 1"> View larger version (15K): org.highwire.dtl.DTLVardef@c798c7org.highwire.dtl.DTLVardef@1ff616eorg.highwire.dtl.DTLVardef@1557dc8org.highwire.dtl.DTLVardef@1b4e89e_HPS_FORMAT_FIGEXP M_FIG C_FIG

Major depressive disorders (MDD) are predicted to become the first cause of burden of disease worldwide in 2030, but 30% of patients still do not respond to antidepressants. Current rodent models of MDD mainly result either from one genetic or one environmental risk factor exposure, not recapitulating the multifactorial and polygenic nature of MDD. We recently generated a polygenic mouse model of MDD from selective breeding after mild stress in the Tail Suspension Test (TST), named H-TST. Here, we selected animals exhibiting high immobility during the Forced Swim Test (FST) to generate a new stable polygenic model of MDD, called H-FST. Unlike our previous H-TST model, H-FST mice did not exhibit any anxiety-or anhedonia-like behaviors, nor did they display any sleep disturbances. Moreover, H-TST and H-FST mice showed opposite response after administration of various antidepressant treatments. The gene expression level in the prefrontal cortex of H-TST and H-FST mice revealed little overlap in genes and biological pathways associated with depressive-like behaviors and opposite dysregulation of excitatory/inhibitory synaptic imbalance. Finally, these two models allowed in humans the identification biomarkers of treatment response specific of clinical subgroup of patients.