Biology subjects

Garcia, A. M.

Publications and source records attributed to Garcia, A. M..

7 recordsLinked to original sources

bioRxiv2026

Innate Immune Dysregulation Precedes Clinical Onset in Neuromyelitis Optica

Neuromyelitis optica spectrum disorder (NMOSD) is a disabling inflammatory central nervous system (CNS) disease characterized by pathogenic aquaporin 4 (AQP4) autoantibodies. The biological events that precede clinical onset remain unknown. In a unique longitudinal NMOSD cohort from the U.S. Department of Defense Serum Repository, with samples collected up to 24 years before onset, we applied discovery proteomics (~5,400 proteins), pan-viral antibody profiling (VirScan), and in silico analyses to characterize preclinical NMOSD versus matched healthy controls. Innate immune activation, particularly CXCL1 elevation, was the dominant immunological feature of preclinical NMOSD, preceding onset by ~12.7 years. AQP4-IgG was detectable more than 3 years before onset, while CNS injury markers increased only after disease manifestation. VirScan identified enhanced CMV-specific antibody reactivity following AQP4- IgG seroconversion, and network analyses revealed interactions between NMOSD-associated and CMV-derived proteins. Together, these findings establish a novel multi-hit model of NMOSD, with implications for understanding antibody-mediated autoimmunity more broadly.

immunology↗

bioRxiv2026

Impact of Amazonian Dance on Speech Performance in People with Parkinson's Disease

Dance-based interventions have consistently been shown to improve limb motor function in Parkinsons disease (PD), yet their potential impact on other motor domains, particularly those supporting laryngeal-orofacial control needed for speech production, remains largely unexplored. Beyond motor speech functions, dance may also influence higher-order language processes, including semantic organization. To test these hypotheses, we conducted a 12-week randomized trial comparing an Amazonian Dance intervention to a matched-physical intensity control condition (Nordic Walking), incorporating automated speech and language analysis to provide objective, fine-grained quantification of communication outcomes. Participants in the dance arm showed significant improvements in prosody (Main Tone), voice quality (Harmonic to Noise Ratio), and semantic organization (Granularity), whereas the walking group showed declines in these metrics. The dance-related gains in prosody and semantics remained significant even after adjusting for demographic, cognitive, and clinical covariates. These findings suggest that dance may enhance both speech-motor and higher-order language functions in PD, potentially through mechanisms such as auditory-motor coupling, improved internal timing, and the engagement of overlapping neural substrates between dance and speech and/or language.

animal behavior and cognition↗

bioRxiv2025

Respiratory syncytial virus nonstructural protein 1 inhibits production of cytokines and chemokines by differentiated primary nasal epithelial cells cultured at air-liquid interface

Respiratory syncytial virus (RSV) is a major cause of severe respiratory infections in children and older adults. Several vaccines have recently been approved, which are all based on the RSV fusion (F) protein. Among the strategies to induce a broader immune response is the development of live-attenuated RSV vaccines, for example by disabling nonstructural protein 1 (NS1). RSV NS1 has been found to modulate the host immune response by repression of interferon (IFN) production. However, functional characterization of this protein was mainly performed in immortalized cell lines, which do not necessarily represent the in vivo situation. Here, we assessed the effect of NS1 mutations on replication and host responses in differentiated primary human nasal epithelial cells (HNEC) cultured at air-liquid interface (ALI), which mimic several physiological properties of the human airways. Using a newly developed yeast-based RSV reverse genetics system, inactivating mutations in the NS1 gene were introduced. These mutations did not affect viral replication in Vero and A549 cells. However, in HNEC we observed a delayed replication of the NS1 mutants compared to the WT virus. Bulk RNA sequencing data from early post infection revealed a stronger antiviral signature in HNEC that were infected with NS1 mutants compared to WT, characterized by upregulation of IFN-{beta} and IFN-{lambda}1/2/3 and chemokines CXCL11 and CCL5. This signature was confirmed by analysis of the cytokines that were released into the HNEC basal medium. Finally, the basal medium containing these cytokines was used for an indirect immune cell migration assay. In this set-up, both WT and NS1 mutant viruses induce migration of mainly neutrophils. In conclusion, this study shows that RSV NS1 supports viral replication not only via inhibition of the production of IFNs, but also by reducing early chemokine production and secretion by epithelial cells. Furthermore, our data highlight the suitability of the ALI transwell model for preclinical assessment of live-attenuated vaccine candidates.

microbiology↗

bioRxiv2025

Impact of Serum Circulating Factors and PDE5 Inhibitor Therapy on Cardiomyocyte Metabolism in Single Ventricle Heart Disease

BackgroundWhile operative and perioperative care continues to improve for single ventricle congenital heart disease (SV), long-term morbidities and mortality remain high. Importantly, phosphodiesterase-5 inhibitor therapies (PDE5i) are increasingly used, however, little is known regarding the direct myocardial effects of PDE5i therapy in the SV population. ObjectivesOur group has previously demonstrated that the failing SV myocardium is characterized by increased PDE5 activity and impaired mitochondrial bioenergetics. Here we sought to determine whether serum circulating factors contribute to pathological metabolic remodeling in SV, and whether PDE5i therapy abrogates these changes. MethodsUsing an established in vitro model whereby primary cardiomyocytes are treated with patient sera +/- PDE5i, we assessed the impact of circulating factors on cardiomyocyte metabolism. Mass spectrometry-based lipidomics and metabolomics were performed to identify phospholipid and metabolite changes. Mitochondrial bioenergetics were assessed using the Seahorse Bioanalyzer and a stable isotope based mitochondrial enzyme activity assay. Relative mitochondrial copy number was quantified using RT-qPCR. ResultsOur data suggest that serum circulating factors contribute to fundamental changes in cardiomyocyte bioenergetics, including impaired mitochondrial function associated with decreased cardiolipin and other phospholipid species, increased reactive oxygen species (ROS) generation, and altered metabolite milieu. Treatment with PDE5i therapy was sufficient to abrogate a number of these metabolic changes, including a rescue of phosphatidylglycerol levels, a reduction in ROS, improved energy production, and normalization of several key metabolic intermediates. ConclusionsTogether, these data suggest PDE5i therapy has direct cardiomyocyte effects and contributes to beneficial cardiomyocyte metabolic remodeling in SV failure.

cell biology↗

bioRxiv2024

Glial cell derived pathway directs regenerating optic nerve axons toward the CNS midline

After optic nerve injury, several retinal ganglion cell (RGC) intrinsic signaling pathways have been shown to enhance RGC survival and RGC axonal growth. In contrast, few extrinsic cues have been identified that guide regenerating RGC axons toward and across the optic chiasm. Here, we use live-cell imaging in larval zebrafish to show that regrowing RGC axons initiate growth toward the midline and extend along a trajectory similar to their original projection. From a candidate genetic screen, we identify the glycosyltransferase Lh3 (also referred to as Plod3) to be required to direct regrowing RGC axons toward the midline during active regeneration. Moreover, we show that transgenic lh3 expression in sox10+ presumptive olig2+ oligodendrocytes located near the optic chiasm restores directed axonal growth in lh3 mutants. Finally, we find that mutants in collagen 18a1 (col18a1), a putative Lh3 substrate, display RGC axonal misguidance phenotypes similar to lh3 mutants, suggesting that lh3 may act through col18a1 during regeneration. Combined, these data identify lh3 as part of a glial derived molecular pathway critical for guiding in vivo regenerating RGC axons toward and across the optic chiasm.

neuroscience↗

bioRxiv2022

Natural language signatures of psilocybin microdosing

Serotonergic psychedelics are being studied as novel treatments for mental health disorders and as facilitators of improved well-being, mental function and creativity. Recent studies have found mixed results concerning the effects of low doses of psychedelics ("microdosing") on these domains. However, microdosing is generally investigated using instruments designed to assess larger doses of psychedelics, which might lack sensitivity and specificity for this purpose. Following a double-blind and placebo-controlled experimental design, we explored natural language as a resource to identify speech produced under the acute effects of psilocybin microdoses, focusing on variables known to be affected by higher doses: verbosity, semantic variability and sentiment scores. Except for semantic variability, these metrics presented significant differences between a typical active microdose of 0.5 g of psilocybin mushrooms and an inactive placebo condition. Moreover, machine learning classifiers trained using these metrics were capable of distinguishing between conditions with high accuracy (AUC{approx}0.8). Our results constitute first proof that low doses of serotonergic psychedelics can be identified from unconstrained natural speech, with potential for widely applicable, affordable, and ecologically valid monitoring of microdosing schedules.

pharmacology and toxicology↗

bioRxiv2021

Impact of protein conformational diversity on AlphaFold predictions

After the outstanding breakthrough of AlphaFold in predicting protein 3D models, new questions appeared and remain unanswered. The ensemble nature of proteins, for example, challenges the structural prediction methods because the models should represent a set of conformers instead of single structures. The evolutionary and structural features captured by effective deep learning techniques may unveil the information to generate several diverse conformations from a single sequence. Here we address the performance of AlphaFold2 predictions under this ensemble paradigm. Using a curated collection of apo-holo conformations, we found that AlphaFold2 predicts the holo form of a protein in 70% of the cases, being unable to reproduce the observed conformational diversity with an equivalent error than in the estimation of a single conformation. More importantly, we found that AlphaFold2s performance worsens with the increasing conformational diversity of the studied protein. This impairment is related to the heterogeneity in the degree of conformational diversity found between different members of the homologous family of the protein under study. Finally, we found that main-chain flexibility associated with apo-holo pairs of conformers negatively correlates with the predicted local model quality score plDDT, indicating that plDDT values in a single 3D model could be used to infer local conformational changes linked to ligand binding transitions.

bioinformatics↗