Biology subjects

Hernandez-Pando, R.

Publications and source records attributed to Hernandez-Pando, R..

6 recordsLinked to original sources

bioRxiv2025

Novel multi-transmitter calyx-like giant synapse revealed in the extended amygdala

We have discovered a highly specialized innervation of the forebrain by pituitary adenylate cyclase activating polypeptide (PACAP) immunohistochemistry originating from the brain stem that uses glutamate, acetylcholine and PACAP and other peptides as neurotransmitters. The parent neurons of the axons are in the Kolliker-Fuse nucleus and their terminals form calyx-like multi-release site synapses in the rodent forebrain extended amygdala similar to the calyx of Held in the auditory brain stem. The latter is a giant, excitatory, cup-like axo-somatic high-fidelity synapse. The PACAP-positive terminals also form enveloping axo-somatic specialization with mixed glutamatergic and cholinergic molecular identities, co-expressing VGluT1, VGluT2, VAChT, and the neuropeptides PACAP, CGRP, and neurotensin, together with calretinin in the presynaptic compartment. We identified a distinct neuronal subpopulation in the pontine Kolliker-Fuse region of the parabrachial complex that gives rise to these calyceal terminals, which engulf PKC/GluD1 somata in the capsular central amygdala and oval bed nucleus of the stria terminalis. Strikingly, GluD1 immunolabeling is concentrated at axo-somatic contact zones apposed to VAChT presynaptic vesicle clusters zones but is absent from postsynaptic densities of conventional type I synapses within the same terminals. The results demonstrate a previously unrecognized multimodal calyx-like synapse in the forebrain, with parallel fast ionotropic and modulatory peptidergic neurotransmission mechanisms, which is a substrate for high-fidelity signal transmission within viscerosensory -emotional circuits. Significance StatementA high-fidelity axo-somatic glutamatergic synapse is exemplified by the calyx of Held in the auditory brainstem, but is unknown in the forebrain. Here we reveal a multimodal calyceal synapse in the extended amygdala formed by glutamatergic afferents of the pontine Kolliker-Fuse nucleus that contain also several neuropeptides. These giant terminals co-package glutamate, acetylcholine, PACAP, CGRP and neurotensin. They envelop select PKC/GluD1 neurons in the capsular central amygdala and oval BNST. These unique forebrain synapses link viscerosensory input from the hindbrain to limbic autonomic centers. Such high-fidelity multimodal transmission is likely to underlie the precise synchronization of emotional and homeostatic control circuits.

neuroscience↗

bioRxiv2024

Mycobacterial EsxG·EsxH (TB9.8·TB10.4) peptides as a subunit vaccine to booster BCG vaccination in an experimental model of pulmonary Tuberculosis

The attenuated Mycobacterium bovis bacillus Calmette-Guerin (BCG) vaccine is currently the only validated vaccine against tuberculosis (TB). In a previous study, we conducted an in-silico selection of four peptides (G1, G2, H1, and H2) derived from the mycobacterial protein antigens TB10.9{middle dot}TB10.4 (EsxG{middle dot}EsxH). Bioinformatic analysis and molecular dynamic simulations predicted these epitopes could be loaded into a MHC-II complex, inducing T and B cell activation. The present study aimed to experimentally validate these peptides as subunit vaccines by determining their cytotoxicity, immunogenicity, and protective efficacy against Mycobacterium tuberculosis (Mtb) in mice when administered as a booster to BCG vaccination. Mice were vaccinated with BCG and, two months later, were subcutaneously immunized with either peptide G1, G2, H1, or H2. One-month post-immunization, mice were challenged with the reference strain H37Rv of moderate virulence or the hypervirulent clinical isolate 09005186. After vaccination and before the challenge, the spleen and lung cells were harvested and stimulated in vitro with the corresponding peptide to measure cytokine expression in CD4+, and CD8+ T cells, as well as the phenotypes of activated effector T cells, proliferative senescence, central and periphery memory CD4+ and CD8+ cells. Additionally, specific IgG antibody titers elicited by each peptide were measured using ELISA. Compared with animals vaccinated only with BCG, boosting BCG vaccination with these peptides provided enhanced protection by significantly prolonging the mice survival, reducing the bacillary load, and decreasing tissue damage (pneumonia). These findings contribute to the broader understanding of peptide-based subunit vaccines and highlight the potential for tailored approaches to enhance protective immunity.

biochemistry↗

bioRxiv2023

Exposure to an enriched environment improves colonic epithelial barrier integrity and attenuates mouse experimental colitis by modulating a Myc-driven gene regulatory network

Withdrawal StatementThe authors have withdrawn their manuscript owing to erroneous labeling in two figures that have recently come to light. Experiments aiming to confirm the data presented are underway. Therefore, the authors do not wish this work to be cited as reference for the project. If you have any questions, please contact the corresponding author.

immunology↗

bioRxiv2022

In silico EsxG·EsxH Rational Epitope Selection: Candidate Epitopes for Vaccine Design against Pulmonary Tuberculosis

Rational design of new vaccines against pulmonary tuberculosis is imperative. EsxG{middle dot}EsxH complex is involved in metal uptake, drug resistance, and immune response evasion. These characteristics make it an ideal target for rational vaccine development. The aim of this study is to show the rational design of epitope-based peptide vaccines by using bioinformatics and structural vaccinology tools. A total of 4.15 {micro}s of Molecular Dynamics simulations were carried out to describe the behavior in solution of heterodimer, single epitopes, and epitopes loaded into MHC-II complexes. In order to predict T and B cell epitopes for antigenic activation, bioinformatic tools were used. Hence, we propose three epitopes with the potential to design pulmonary tuberculosis vaccines. The possible use of the proposed epitopes includes subunit vaccines, as a booster in BCG vaccination to improve its immune response, as well as the generation of antibodies that interfere with the mycobacterium tuberculosis homeostasis, affecting its survival.

bioinformatics↗

bioRxiv2020

In silico secretome characterization of clinical Mycobacterium abscessus isolates provides insights into antigenic differences

Mycobacterium abscessus (MAB) is a widely disseminated pathogenic non-tuberculous mycobacterium (NTM). Like with M. tuberculosis complex (MTBC), excreted / secreted (ES) proteins play an essential role for its virulence and survival inside the host. ES proteins contain highly immunogenic proteins, which are of interest for novel diagnostic assays and vaccines. Here, we used a robust bioinformatics pipeline to predict the secretome of the M. abscessus ATCC 19977 reference strain and fifteen clinical isolates belonging to all three MAB subspecies, M. abscessus subsp. abscessus, M. abscessus subsp. bolletii, and M. abscessus subsp. massiliense. We found that ~18% of the proteins encoded in the MAB genomes were predicted as secreted and that the three MAB subspecies shared > 85 % of the predicted secretomes. MAB isolates with a rough (R) colony morphotype showed larger predicted secretomes than isolates with a smooth (S) morphotype. Additionally, proteins exclusive to the secretomes of MAB R variants had higher antigenic densities than those exclusive to S variants, independently of the subspecies. For all investigated isolates, ES proteins had a significantly higher antigenic density than non-ES proteins. We identified 337 MAB ES proteins with homologues in previously investigated M. tuberculosis secretomes. Among these, 222 have previous experimental support of secretion, and some proteins showed homology with protein drug targets reported in the DrugBank database. The predicted MAB secretomes showed a higher abundance of proteins related to quorum-sensing and Mce domains as compared to MTBC indicating the importance of these pathways for MAB pathogenicity and virulence. Comparison of the predicted secretome of M. abscessus ATCC 19977 with the list of essential genes revealed that 99 secreted proteins corresponded to essential proteins required for in vitro growth. All predicted secretomes were deposited in the Secret-AAR web-server (http://microbiomics.ibt.unam.mx/tools/aar/index.php).

bioinformatics↗

bioRxiv2020

Host-derived lipids from tuberculous pleurisy impair macrophage microbicidal-associated metabolic activity

Mycobacterium tuberculosis (Mtb) regulates the macrophage metabolic state to thrive in the host. Yet, the responsible mechanisms remain elusive. Macrophage activation towards the microbicidal (M1) program depends on the HIF-1 -mediated metabolic shift from oxidative phosphorylation towards glycolysis. Here, we asked whether a tuberculosis (TB) microenvironment changes the M1 macrophage metabolic state. We exposed M1 macrophages to the acellular fraction of tuberculous pleural effusions (TB-PE), and found lower glycolytic activity, accompanied by elevated levels of oxidative phosphorylation and bacillary load, compared to controls. The host-derived lipid fraction of TB-PE drove these metabolic alterations. HIF-1 stabilization reverted the effect of TB-PE by restoring M1 metabolism. As a proof-of-concept, Mtb-infected mice with stabilized HIF-1 displayed lower bacillary loads and a pronounced M1-like metabolic profile in alveolar macrophages. Collectively, we demonstrate that host-derived lipids from a TB-associated microenvironment alter the M1 macrophage metabolic reprogramming by hampering HIF-1 functions, thereby impairing control of Mtb infection.

immunology↗