Biomedical Research Networking Center on Neurodegenerative Diseases

Psychedelics have garnered significant interest for their therapeutic potential in mental health conditions such as depression, anxiety, and post-traumatic stress disorder. While research has primarily focused on well-studied psychedelics, phenethylamine derivatives have also gathered interest for their potential therapeutic applications. Thus, this study aims to investigate the pharmacological profile, safety and therapeutic potential of novel N-(2-fluorobenzyl) phenethylamine analogs (NBFs) of the 2C-X series-25C-NBF, 25B-NBF, and 25I-NBF. NBFs displayed high affinity and selectivity for the 5-HT2A receptor and demonstrated bias factors (defined in our study as the preference for Gq over β-arrestin pathways at 5-HT2A receptor) similar to that of 5-HT. Acute administration induced moderate head-twitch responses without affecting locomotion or pre-pulse inhibition. Our studies revealed no rewarding effects in mice nor reinforcing effects or changes in accumbal dopamine levels in rats after NBFs administration. Further characterization of 25C-NBF revealed psychoplastogenic effects (dendritogenesis, spinogenesis and increased Bdnf mRNA levels) both in vitro and in vivo. In addition, 25C-NBF reduced despair-like behavior in response to acute stress and exerted rapid antidepressant effects in a model of anhedonia-like behavior induced by chronic corticosterone administration. Taken together, these findings suggest that 25C-NBF, and further analogs, may hold potential as novel antidepressants with a rapid onset of action and a favorable safety profile in terms of no abuse potential or sensorimotor gating deficits.

Brain aging consists of a progressive loss of functional capacities, which is associated with a progressive cognitive decline and can lead to neurodegenerative diseases. Studies comparing the underlying molecular mechanisms of the human hippocampus between young and older adults remain scarce. In our study, we completed a transcriptomic analysis from hippocampal samples of different ages and performed 2 complementary analyses. A comparison between young and old groups revealed a set of genes differentially expressed in aged individuals linked to inflammation and immune system pathways, DNA repair, metabolism, or neural activity. Correlation analysis showed that the expression of an additional subset of 6 genes was associated with chronological aging. Among them, further analysis identified RAD23B as the most significant gene with a negative correlation of its mRNA and protein expression with age in the human hippocampus. Its expression was even lower in patients with Alzheimer's disease. RAD23B was mostly expressed in neurons and astrocytes, where studies in human primary cultures uncovered that it is required for cell survival and function. In summary, these results unravel dynamic gene expression changes that distinguish young from older adults and identify RAD23B as a putative biomarker and regulator of cell aging in the brain.

The hypothalamic-pituitary-gonadal axis (HPG) controls pubertal development, sexual maturation, and fertility. We identified a role of hypothalamic microglia in controlling the HPG axis through receptor activator of nuclear factor κβ (Rank) signaling. Whole-body and microglia Rank depletion led to hypogonadotropic hypogonadism (HH) resulting from an alteration in gonadotropin-releasing hormone (GnRH) neuron function. In addition, we identified rare gene variants of RANK in patients with HH. Transcriptional profiling upon Rank loss revealed defective microglia activation and morphological alterations in the median eminence, decreasing the contacts and engulfment of GnRH terminal projections and impairing GnRH neuronal responses to kisspeptin. Overall, our data uncover the microglia as regulator of GnRH neuronal function through Rank signaling, with potential implications for reproductive maturation and fertility.

BackgroundVariant Creutzfeldt–Jakob disease (vCJD) is a fatal transmissible prion disorder attributed primarily to the ingestion of meat from cattle infected with bovine spongiform encephalopathy (BSE), and it can also be transmitted through blood transfusions and occupational exposure in laboratories. As of July 2024, 233 deaths had been recorded in 12 countries, mostly in the United Kingdom (UK) and France.ObjectiveThis study aimed to describe the results of vCJD surveillance in Spain from 1993 to 2021 and the responses to those results.MethodsSurveillance spanned the following three periods: 1993–2000, when neurologists and public health professionals created a network for reporting potential cases; 2001–2010, when diagnostic criteria were improved, and management guidelines were published; and 2011–2021, when reporting and post-mortem analyses decreased.ResultsFive deaths due to vCJD were identified through post-mortem between 2005 and 2008 (ages ranging from 25 to 64 years). In two cases involving a mother and her son, their prion strain was similar to the strain found in UK humanized mouse models, suggesting a link to BSE. Three cases had recently undergone invasive dental procedures, one had undergone a fibroscopy, and another had donated blood several times. The majority of prevention measures were adopted with a delay.ConclusionSpain is the third most affected country by vCJD. Interruption of beef imports from the UK and control of the local BSE epizootic may have helped control vCJD in Spain since 2009. The increase in vCJD deaths through occupational exposures in laboratory work in other countries since 2016 should act as a warning signal for the surveillance of all forms of human transmissible spongiform encephalopathies.

INTRODUCTION:Bilingualism is among several lifestyle factors associated with protection against cognitive decline, yet the biological mechanisms through which it exerts these effects remain poorly understood.METHODS:We compared neuropsychological functioning and biofluid markers of brain health between active (n = 280) and passive (n = 287) Spanish-Catalan bilinguals with biomarker-confirmed Alzheimer’s disease (AD).RESULTS:Active bilinguals outperformed passive bilinguals on tests assessing attention/executive functions, language, and visuospatial/visuomotor functioning, demonstrating resilience given the same AD biological stage across participants. Active bilinguals also exhibited significant differences in cerebrospinal fluid and plasma biomarkers of amyloid burden and neuroinflammation, suggesting both resilience and resistance to AD pathophysiologic mechanisms.DISCUSSION:The protective effects of bilingual experience may engage both resilience and resistance to AD pathophysiology mechanisms. These results underscore the importance of capturing bilingualism in aging cohorts and the study of how lifestyle and sociocultural factors shape the biological expression of neurodegenerative disease.

STIM1 is a transmembrane protein localized in the endoplasmic reticulum (ER), where it acts as a calcium ion sensor, activating store-operated Ca2+ entry upon ER Ca2+ depletion. Via cellular calcium influx, STIM1 is thought to indirectly affect mitochondrial calcium content. Here we show that STIM1 also interacts with mitochondrial proteins such as PTPIP51 and GRP75, suggesting its presence in mitochondria-associated ER membranes (MAMs), which are specialized ER regions that facilitate ER-mitochondria communication. Lowering STIM1 expression disrupts ER-to-mitochondria Ca2+ transfer, reduces basal mitochondrial Ca2+ levels, impairs maximal mitochondrial respiration, and reduces ATP production. The STIM1-GRP75 interaction depends on STIM1's Ca2+-sensing ability. ER Ca2+ depletion or the constitutive-open R429C mutation both reduce STIM1 binding to GRP75, suggesting that conformational changes in STIM1 play a role in this interaction. Deletion analysis revealed that the STIM1 (551-611) segment is crucial for GRP75 binding, as the peptide STIM1(551-611) binds GRP75, while STIM1(Δ551-611) shows reduced binding. These findings reveal a previously unrecognized role of STIM1 in direct inter-organelle communication.

ObjectiveSialidosis type I (ST‐1) is an autosomal‐recessive, very rare, progressive lysosomal storage disorder caused by pathogenic variants in NEU1. It is clinically characterized by progressive ataxia, myoclonic seizures (MS), bilateral tonic–clonic seizures (BTCS), and distinctive ophthalmological findings. Given the lack of curative options, in this study, we investigated symptomatic treatment strategies, with a particular focus on the efficacy of antiseizure medications (ASMs).MethodsWe describe the clinical course of a patient followed from diagnosis to 18 years of age, and review seven additional cases from our cohort. In parallel, we conducted a narrative review of the literature (PubMed, January 2010–September 2025) to identify published reports containing therapeutic data.ResultsTherapeutic responses were evaluated in a total of 33 cases (8 from our cohort, 25 from published sources). Although available data are insufficient to define standardized treatment guidelines, some ASMs, such as ACZ, PER, LEV, VPA, CZP, and ZNS, demonstrated fairly consistent efficacy in managing MS and BTCS. Sodium oxybate or deep‐brain stimulation may be considered in refractory cases.SignificanceProspective documentation of clinical course and treatment outcomes—ideally through an international registry—is crucial to improve patient care and inform therapeutic strategies.Plain Language SummarySialidosis type I (ST‐1) is a very rare genetic disorder causing movement problems and seizures, with no cure available yet. We followed 8 patients and reviewed 25 published cases to assess treatments focusing on myoclonic seizure (MS) control. Some antiseizure medications showed benefit. However, we have too little data to make clear recommendations. To improve patients' treatment and to choose the most appropriate therapy, it would be important to follow patients over a longer period of time, for example, in an international registry.

Cerebrospinal fluid (CSF) biomarkers are central to Alzheimer's disease (AD) diagnosis and research. However, CSF composition is shaped not only by neurodegeneration, but also by underlying physiological and pathological processes that remain poorly characterized. By integrating multi-omics data from the deeply characterized memory-clinic ACE CSF cohort (N=1,372), the Global Neurodegeneration Proteomics Consortium (N=1,863), and publicly available quantitative trait loci data, we reveal that 73.2-85.9% of the molecular variance in CSF omics data is driven by two main factors: one reflecting CSF turnover rate, and another representing blood-brain barrier (BBB) integrity. CSF turnover mainly determines brain-derived molecules, while BBB damage leads to increased blood-derived protein abundance. CSF turnover/clearance severely impacted core AD biomarker levels, affecting the classification of subjects in the A/T framework. Adjusting biomarker levels for OPCML, a novel reference marker, improved biomarker-based prediction of AD progression and removed confounded associations, revealing a proteomic signature of sporadic AD pathology that closely resembles that of autosomal dominant AD. Finally, using the ACE CSF cohort as discovery (N=1,221) and Knight ADRC as replication (N=1,073), we report a curated AD signature comprising 446 unique proteins. Our findings identify CSF dynamics as a major source of molecular variation, reshaping the interpretation of CSF biomarkers.