Biology subjects

Gil-Bea, F. J.

Publications and source records attributed to Gil-Bea, F. J..

6 recordsLinked to original sources

bioRxiv2026

Criticality-related dynamics accompany long-term functional decline in primary cortical MEA cultures

Primary cortical neuron cultures are widely used to study network development and decline, but their long-term electrophysiological trajectories are poorly characterized. We used multi-electrode arrays to longitudinally monitor Wistar rat cortical cultures for up to ~730 days in vitro (DIV), combining activity measures with survival analysis and criticality metrics. Wells shared an early developmental phase, with mean firing rate peaking at 12-14 Hz around DIV 100-150, before diverging into two phenotypes: early-death wells, showing progressive loss of burst organization, longer inter-burst intervals, shorter bursts, and steep declines in active-electrode recruitment; and long-survival wells, which sustained organized bursting and measurable activity well beyond DIV 400, in some cases past DIV 700. Cox proportional-hazards modeling with FDR correction across thirteen candidate features identified burst duration, inter-burst interval, synchrony, mean firing rate, branching ratio, and Kappa index as significant predictors of time to network failure. Criticality metrics offered the most mechanistic insight: in early-death wells, branching ratio declined toward zero and Kappa index rose toward its upper bound as networks approached silencing. Beyond their average levels, the rate of change of branching ratio and Kappa index over recordings was the strongest correlate of survival time among all criticality metrics. Neuronal avalanche size and duration exponents and their scaling relation, remained consistent with scale-free dynamics in both phenotypes while networks were active, though avalanche occurrence rate declined progressively in early-death wells without reaching significance as an independent predictor. These results show that long-term network survival is not determined by firing rate alone, but by preserved burst organization, sustained electrode recruitment and near-critical propagation dynamics. This work offers one of the longest electrophysiological characterizations of rodent cortical cultures to date and identifies criticality-based metrics as promising tools for predicting network decline and evaluating interventions to preserve long-term neuronal function.

neuroscience↗

bioRxiv2025

Assessment of the pharmacological and safety profile of the small molecule MP-004 after topical eye drops administration

MP-004 is a novel small molecule under development as a non-invasive therapeutic for inherited retinal dystrophies (IRDs), including retinitis pigmentosa. Here, we evaluated its ocular concentration and safety profile following topical administration in three animal species --mouse, rabbit, and pig--. MP-004 formulation with 0.3% hyaluronic acid significantly enhanced retinal concentration in mice compared to non-formulated compound (6.67 vs 1.27 {micro}g/g at 4 h). MP-004 reached therapeutically relevant retinal concentrations in all species tested, with minimal systemic exposure: in mice, levels detected in serum were lower than 5 ng/mL while in rabbits, the compound was undetectable in blood and peripheral tissues 12 h post-dose. Seven-day repeated-dose toxicity studies in mice and rabbits showed no systemic or ocular toxicity. In rabbits, only transient ocular redness was observed post-administration, with no evidence of corneal damage or systemic adverse effects. Hematological and biochemical parameters in both species remained within normal limits. Importantly, retinal and optic nerve concentrations remained detectable in rabbits 7 days after final dosing, while the compound was eliminated systemically, supporting prolonged target tissue retention. These findings demonstrate that MP-004 is well tolerated and achieves effective retinal concentrations via topical delivery, overcoming a major barrier in retinal drug development. The favorable pharmacokinetic and safety profile across species, including anatomically relevant models, supports MP-004s advancement toward regulatory preclinical studies and clinical translation as a non-invasive therapy for IRDs.

pharmacology and toxicology↗

bioRxiv2025

Computational Analysis of ELOVL6 Structure and Inhibition for Rational Drug Design

ELOVL6 is a key enzyme in long-chain fatty acid elongation, catalyzing the conversion of C16 fatty acids into C18 fatty acids. While its role in lipid metabolism is well established, recent studies have linked ELOVL6 to metabolic and neurodegenerative diseases, making it an attractive therapeutic target. However, the absence of a resolved crystal structure and limited mechanistic understanding of its inhibition pose significant challenges for drug discovery. In this study, we employ a multi-tiered computational approach, including structure prediction, molecular dynamics (MD) simulations, and free energy calculations, to investigate the structural basis of ELOVL6 function and inhibition. We identify the most thermodynamically favorable substrate binding pathway and characterize key conformational changes associated with ligand binding. By analyzing potential inhibitor binding pockets, we determine that known inhibitors preferentially target the active site, and we validate their binding affinities against experimental data. Additionally, by comparing ELOVL6 with homologous elongases, we pinpoint potentially key amino acid residues responsible for selectivity, providing insights that could guide structure-based drug design. Our findings establish a mechanistic framework for rational inhibitor development, offering a foundation for future efforts in optimizing ELOVL6-targeting therapeutics.

bioinformatics↗

bioRxiv2024

Lipid Dysregulation Unveil the Intricate Interplay of Lysosomal and Mitochondrial Changes in Frontotemporal Dementia with GRN Haploinsufficiency

This study investigates the cellular pathology resulting from haploinsufficiency of progranulin (PGRN) in frontotemporal dementia (FTD) associated with granulin (GRN) mutations. Utilizing fibroblasts from FTD patients carrying a distinctive GRN mutation (c.709-1G>A), we observed lysosomal and lipofuscin accumulation, impaired lysosomal function, compromised autophagic flux, and mitochondrial abnormalities. Notably, recombinant human progranulin (rhPGRN) treatment restored lysosomal acidification, mitigated mitochondrial defects, and demonstrated beneficial effects. FTD-GRN fibroblasts exhibited abnormal lipid metabolism with increased lipid droplet formation, influenced by GRN haploinsufficiency and modulated by rhPGRN. Under nutrient-rich conditions, lipid droplet dynamics were shaped by autophagy and mitochondrial processes, potentially due to impaired fatty acid oxidation. These findings highlight a direct association between GRN deficiency and altered lysosomal-mitochondrial interactions, influencing lipid metabolism and contributing to FTD pathogenesis. The documented lysosomal dysfunction, impaired autophagy, mitochondrial anomalies, and altered lipid metabolism collectively suggest a complex interplay of cellular processes in the development of FTD-GRN.

neuroscience↗

bioRxiv2024

Novel FKBP12 ligand promotes functional improvement in SOD1-G93A ALS mice

Amyotrophic lateral sclerosis (ALS) is a devastating neurodegenerative disease with limited treatment options. ALS pathogenesis involves intricate processes within motor neurons (MNs), characterized by dysregulated Ca2+ influx and buffering in early ALS-affected MNs. This study proposes the modulation of ryanodine receptors (RyRs), key mediators of intracellular Ca2+, as a therapeutic target. A novel class of novel FKBP12 ligands that show activity as cytosolic calcium modulators through stabilizing RyR channel activity, were tested in the SOD1G93A mouse model of ALS. Different outcomes were used to assess treatment efficacy including electrophysiology, histopathology, neuromuscular function, and survival. Among the novel FKBP12 ligands, MP-010 was chosen for its central nervous system availability. Chronic administration of MP-010 to SOD1G93A mice produced a dose-dependent preservation of motor nerve conduction, with the 61 mg/kg dose significantly delaying the onset of motor impairment. This was accompanied by improved motor coordination, increased innervated endplates, and significant preservation of MNs in the spinal cord of treated mice. Notably, MP-010 treatment significantly extended lifespan by an average of 10 days compared to vehicle. In conclusion, FKBP12 ligands, particularly MP-010, exhibit promising neuroprotective effects in ALS, highlighting their potential as novel therapeutic agents. Further investigations into the molecular mechanisms and clinical translatability of these compounds are needed for their application in ALS treatment.

neuroscience↗

bioRxiv2021

A novel Alex3/Gαq protein complex regulating mitochondrial dynamics, dendritic complexity, and neuronal survival

In neurons, mitochondrial dynamics and trafficking are essential to provide the energy required for neurotransmission and neuronal activity. Recent studies point to GPCR and G proteins as important regulators of mitochondrial dynamics and energy metabolism. Here we show that activation of Gq negatively regulates mitochondrial dynamics and trafficking in neurons. Gq interacts with the mitochondrial trafficking protein Alex3. By generating a CNS-specific armcx3 knock-out mouse line, we demonstrate that Alex3 is required for Gq effects on mitochondrial dynamics and trafficking, and dendritic growth. Armcx3-deficient mice present decreased OXPHOS complex and ER stress response protein levels, which correlate with increased neuronal death, motor neuron and neuromuscular synaptic loss, and severe motor alterations. Finally, we show that Alex3 disassembles from the Miro1/Gq complex upon calcium rise. These data uncover a novel Alex3/Gq complex that regulates neuronal mitochondrial dynamics and neuronal death and allows the control of mitochondrial functions by GPCRs.

cell biology↗