Biology subjects

Castillo, M.

Publications and source records attributed to Castillo, M..

12 recordsLinked to original sources

bioRxiv2026

Atlas-Guided Cell-Specific Transcriptomics Identifies Pathway-Level Remodeling of Human Hypothalamic CRH Neurons in Opioid Use Disorder

Opioid use disorder (OUD) disrupts hypothalamic stress signaling, yet the molecular state of human paraventricular nucleus (PVN) corticotropin-releasing hormone (CRH) neurons remains poorly defined. Using single-nucleus RNA sequencing of 343,819 human hypothalamic nuclei, we applied complementary human HYPOMAP/MapMyCells and mouse PVN Atlas strategies that independently converged on the standardized Allen Brain Map subcluster Splat 410 843, providing cross-atlas validation of a rare CRH-enriched PVN population. Integrated GO, Reactome and KEGG analysis revealed OUD-associated enrichment of synaptic, junctional, cytoskeletal, receptor-signaling and ion transport programs, with relative enrichment of RNA processing, ER Golgi/vesicular, endolysosomal and glycan-related functions in controls. Targeted neuropeptide analysis further identified nominal increases in OXT, GHR, GAL and PRLR and decreases in VIP, AGRP, NPY, CRHBP and CALCR. Together, these findings define a reproducible human PVN CRH population and identify coordinated pathway and neuropeptide remodeling in OUD.

genomics↗

bioRxiv2026

Cell-type-specific architecture of the hypothalamus in a socially plastic vertebrate

The hypothalamus orchestrates social behaviors by integrating physiological state with environmental information, but the cellular substrates of this plasticity remain unresolved. We combined single-cell and spatial transcriptomics to generate a cell-type map of the hypothalamus in Astatotilapia burtoni, a cichlid fish that forms dynamic social hierarchies. We identified 28 neuronal, glial, neurogenic, and immune cell populations and mapped their organization across hypothalamic nuclei. Social status, sex, and reproductive state engaged coordinated, cell-type-specific transcriptional programs, revealing modular deployment of steroid hormone signaling and plasticity-associated genes. The atlas identified elevated sst1.1 expression in the hypothalamus of dominant males that we localized to the teleost VMH. CRISPR-Cas9 disruption of sst1.1 increased body size, suggesting a role for optimal metabolic and energy allocation. These results define a cellular framework for understanding how hypothalamic plasticity enables flexible social behavior.

neuroscience↗

bioRxiv2026

Autosomal dominant CDC45 deficiency with allelic expression bias causes a novel genetic disease of the immune system

Here we describe a damaging heterozygous variant in CDC45 in an individual with common variable immunodeficiency (CVID) and recurrent viral infections. This individual has variably decreased number of circulating NK cells, disruption in the ratio of CD56bright to CD56dim cells, and consistently decreased NK cell function. Interestingly, the inherited CDC45 variant is also present in a sibling with less severe clinical manifestations; we determined that allelic bias of the damaging allele accounts for this differential expressivity. As previously reported for other helicase variants that cause inborn errors of immunity (IEI), we found cell cycle defects in immune cells from the proband that lead to reduced survival of NK cells. Together, these findings link another member of the core replicative helicase complex to inborn errors of immunity and highlight the sensitivity of NK cells to these variants. They also define another case of allelic bias contributing to variable expressivity of an IEI gene.

immunology↗

bioRxiv2026

GluN2D-containing NMDA receptors regulate dentate gyrus function by facilitating granule cell activity and mediating synaptic plasticity

N-Methyl-D-aspartate ionotropic glutamate receptors (NMDARs) are crucial for synaptic transmission, long-term plasticity, neuronal activity, and cognition. Consistent with these functions, NMDAR dysfunction is linked to several brain disorders, including Alzheimers disease, autism, schizophrenia, and depression. NMDARs are tetrameric complexes composed of two essential GluN1 subunits and two distinct GluN2 subunits (GluN2A-D) that define their functional characteristics. Although the roles of GluN2A and GluN2B, which are highly expressed in the brain, have been extensively studied, much less is known about GluN2D in brain function. Using selective GluN2D antagonists in the mature rodent brain and a conditional GluN2D knockout model, we assessed the role of GluN2D-containing NMDARs in dentate granule cells (GCs). We found that these receptors are tonically active, primarily extrasynaptic, and facilitate GC action-potential firing. Additionally, physiologically relevant presynaptic and postsynaptic activity patterns induced strong long-term potentiation of NMDAR-mediated transmission at medial perforant path synaptic inputs. This plasticity was likely driven by lateral diffusion of GluN2D and supported by non-canonical glutamate delta-1 (GluD1) receptors. Finally, removing GluN2D from excitatory cells in the dentate gyrus impaired spatial memory. Overall, our findings demonstrate that GluN2D-containing NMDARs are vital for hippocampal function, likely by modulating GC activity and mediating NMDAR synaptic plasticity. TEASERGluN2D-containing NMDA receptors control dentate gyrus function by regulating neuronal firing and synaptic plasticity

neuroscience↗

bioRxiv2025

A broad-spectrum, biocompatible, virucidal polymer reduces chikungunya virus in murine models

Autochthonous transmission of arboviruses poses significant threats to global health and economies. Yet, no effective antivirals exist. Building on our previous antiviral star-polymer, we designed zwitterionic star-polymers for efficacy in high protein environments. A polymer with 12% positively charged monomer (Zwitterionic Polymer-ZP12) exhibited broad-spectrum, biocompatible antiviral activity against Alphaviridae, Flaviviridae, Herpesviridae, and Picornaviridae. Using murine models for Chikungunya virus (CHIKV) infection, ZP12 treatment (10 mg/kg every 24 hours for 7 days) reduced tissue viral load by 90% 3 days post-infection and significantly alleviated CHIKV-induced joint swelling. Mechanistically, ZP12 downregulated CHIKV-driven immunopathogenesis by reducing viral load and dampening CD4+ T cell and macrophage activation in virus-infected joints. With no current antiviral interventions for these arboviruses, ZP12 represents a promising intervention for combating future pandemics.

microbiology↗

bioRxiv2023

iPSC-based modeling of helicase deficiency reveals impaired cell proliferation and increased apoptosis after NK cell lineage commitment

While monogenic variants in CDC45-MCM-GINS (CMG) replisome proteins cause human natural killer cell deficiencies (NKD), family members with the same inherited variants often have variable clinical and cellular phenotypes. We investigated two siblings with inherited compound heterozygous GINS4 variants but variable disease expressivity. Cell cycle impairment and increased apoptosis were detected following NK cell lineage commitment but not in pluripotent cells. While this effect was detected in both siblings, the efficiency of NK cell differentiation was variable and correlated with differential clinical severity of NKD. Further investigation of allelic expression of inherited GINS4 variants demonstrated expected biallelic expression of GINS4 in pluripotent cells and progenitors. However, allelic bias in lineage-committed NK cells led to over- or under-representation of more damaging GINS4 heterozygous variants associated with differential cellular and clinical severity. This study identifies allelic bias that causes phenotypic variation of monogenic diseases and defines mechanisms underlying immunodeficiency.

cell biology↗

bioRxiv2023

Characterization and optimization of variability in a human colonic epithelium culture model

Animal models have historically been poor preclinical predictors of gastrointestinal (GI) directed therapeutic efficacy and drug-induced GI toxicity. Human stem and primary cell-derived culture systems are a major focus of efforts to create biologically relevant models that enhance preclinical predictive value of intestinal efficacy and toxicity. The inherent variability in stem-cell-based complex cultures makes development of useful models a challenge; the stochastic nature of stem-cell differentiation interferes with the ability to build and validate robust, reproducible assays that query drug responses and pharmacokinetics. In this study, we aimed to characterize and reduce potential sources of variability in a complex stem cell-derived intestinal epithelium model, termed RepliGut(R) Planar, across cells from multiple human donors, cell lots, and passage numbers. Assessment criteria included barrier formation and integrity, gene expression, and cytokine responses. Gene expression and culture metric analyses revealed that controlling for stem/progenitor-cell passage number reduces variability and maximizes physiological relevance of the model. After optimizing passage number, donor-specific differences in cytokine responses were observed in a case study, suggesting biologic variability is observable in cell cultures derived from multiple human sources. Our findings highlight key considerations for designing assays that can be applied to additional primary-cell derived systems, as well as establish utility of the RepliGut(R) Planar platform for robust development of human-predictive drug-response assays.

cell biology↗

bioRxiv2023

β1 integrins regulate cellular behaviors and cardiomyocyte organization during ventricular wall formation

AimsThe mechanisms regulating the cellular behavior and cardiomyocyte organization during ventricular wall morphogenesis are poorly understood. Cardiomyocytes are surrounded by extracellular matrix (ECM) and interact with ECM via integrins. This study aims to determine whether and how {beta}1 integrins regulate cardiomyocyte behavior and organization during ventricular wall morphogenesis in the mouse. Methods and ResultsWe applied mRNA deep sequencing and immunostaining to determine the expression repertoires of /{beta} integrins and their ligands in the embryonic heart. Integrin {beta}1 subunit ({beta}1) and some of its ECM ligands are asymmetrically distributed and enriched in the luminal side of cardiomyocytes, while fibronectin surrounds cardiomyocytes, creating a network for them. Itgb1, which encodes the {beta}1 integrin subunit, was deleted via Nkx2.5Cre/+ to generate myocardial-specific Itgb1 knockout (B1KO) mice. B1KO hearts display an absence of trabecular zone but a thicker compact zone. The abundances of hyaluronic acid and versican are not significantly different. Instead, fibronectin, a ligand of {beta}1, was absent in B1KO. We examined cellular behaviors and organization via various tools. B1KO cardiomyocytes display a random cellular orientation and fail to undergo perpendicular cell division, be organized properly, and establish the proper tissue architecture to form trabeculae. The reduction of Notch1 activation was not the cause of the abnormal cellular organization in B1KO hearts. Mosaic clonal lineage tracing shows that Itgb1 regulates cardiomyocyte transmural migration and proliferation autonomously. Conclusions{beta}1 is asymmetrically localized in the cardiomyocytes, and its ECM ligands are enriched in the luminal side of the myocardium and surrounding cardiomyocytes. {beta}1 integrins are required for cardiomyocytes to attach to the ECM network. This engagement provides structural support for cardiomyocytes to maintain shape, undergo perpendicular division, and establish cellular organization. Deletion of Itgb1, leading to ablation of {beta}1 integrins, causes the dissociation of cardiomyocytes from the ECM network and failure to establish tissue architecture to form trabeculae.

developmental biology↗

bioRxiv2022

Cellular stress modulates severity of the acute respiratory distress syndrome in COVID-19

Inflammation is a central pathogenic feature of the acute respiratory distress syndrome (ARDS) in COVID-19. Previous pathologies such as diabetes, autoimmune or cardiovascular diseases become risk factors for the severe hyperinflammatory syndrome. A common feature among these risk factors is the subclinical presence of cellular stress, a finding that has gained attention after the discovery that BiP (GRP78), a master regulator of stress, participates in the SARS-CoV-2 recognition. Here, we show that BiP serum levels are higher in COVID-19 patients who present certain risk factors. Moreover, early during the infection, BiP levels predict severe pneumonia, supporting the use of BiP as a prognosis biomarker. Using a mouse model of pulmonary inflammation, we demonstrate that cell surface BiP (cs-BiP) responds by increasing its levels in leukocytes. Neutrophiles show the highest levels of cs-BiP and respond by increasing their population, whereas alveolar macrophages increase their levels of cs-BiP. The modulation of cellular stress with the use of a clinically approved drug, 4-PBA, resulted in the amelioration of the lung hyperinflammatory response, supporting the anti-stress therapy as a valid therapeutic strategy for patients developing ARDS. Finally, we identified stress-modulated proteins that shed light into the mechanism underlying the cellular stress-inflammation network in lungs.

cell biology↗

bioRxiv2022

Heterosynaptic NMDA Receptor Plasticity in Hippocampal Dentate Granule Cells

The dentate gyrus is a key relay station that controls information transfer from the entorhinal cortex to the hippocampus proper. This process heavily relies on dendritic integration by dentate granule cells (GCs) of excitatory synaptic inputs from medial and lateral entorhinal cortex via medial and lateral perforant paths (MPP and LPP, respectively). N-methyl-D-aspartate receptors (NMDARs) can contribute significantly to the integrative properties of neurons. While early studies reported that excitatory inputs from entorhinal cortex onto GCs can undergo activity-dependent long-term plasticity of NMDAR-mediated transmission, the input-specificity of this plasticity along the dendritic axis remains unknown. Here, we examined the NMDAR plasticity rules at MPP-GC and LPP-GC synapses using physiologically relevant patterns of stimulation in acute rat hippocampal slices. We found that MPP-GC, but not LPP-GC synapses, expressed homosynaptic NMDAR-LTP. In addition, induction of NMDAR-LTP at MPP-GC synapses heterosynaptically potentiated distal LPP-GC NMDAR plasticity. The same stimulation protocol induced homosynaptic -amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR)-LTP at MPP-GC but heterosynaptic AMPAR-LTD at distal LPP synapses, demonstrating that NMDAR and AMPAR are governed by different plasticity rules. Remarkably, heterosynaptic but not homosynaptic NMDAR-LTP required Ca2+ release from intracellular, ryanodine-dependent Ca2+ stores. Lastly, the induction and maintenance of both homo- and heterosynaptic NMDAR-LTP were blocked by GluN2D antagonism, suggesting the recruitment of GluN2D-containing receptors to the synapse. Our findings uncover a mechanism by which distinct inputs to the dentate gyrus may interact functionally and contribute to hippocampal-dependent memory formation. Significance StatementNMDARs are key players in synaptic plasticity. In addition to their classical role as coincidence detectors and triggers of AMPAR plasticity, there is compelling evidence that NMDARs can undergo activity-dependent plasticity independent of AMPAR plasticity. However, whether NMDAR-plasticity is expressed heterosynaptically remains unclear. Here, in the dentate gyrus of the hippocampus, we show that the induction of burst timing-dependent LTP of NMDAR-mediated transmission at proximal medial perforant path synapses is accompanied by heterosynaptic NMDAR-LTP at lateral perforant path synapses. These findings provide the first evidence for heterosynaptic NMDAR plasticity, which may have important consequences on the dendritic integration of functionally distinct excitatory inputs by dentate granule cells.

neuroscience↗

bioRxiv2019

High prevalence of precocious menarche in Puerto Barrios, Guatemala

BackgroundAge of menarche is variable between women with a median age of 14 years old worldwide, and averages ranging from 12-13 years old in developed countries to 15-16 years old in low and middle-income countries. Precocious menarche, occurring before age 11, is rare, with a prevalence of 1.4 to 2.3% in most worldwide populations. Precocious menarche is poorly understood but is associated with early puberty and is a risk factor for pre-teen birth. In studying HPV prevalence in Latin America, we identified a community with a very high rate of precocious menarche. Objective(s)Describe the patterns of precocious menarche in Guatemala. Study DesignReproductive histories were collected from 3385 cancer-free women at the time of routine Pap smear from 4 sites in Guatemala including hospitals in Guatemala City and Puerto Barrios, Izabal. Statistical analyses included determination of the age-specific prevalence of menarche and linear regression to determine the effect of year of birth, study site, number of births and miscarriages, on the age at menarche. ResultsCompared with a low prevalence of precocious menarche observed in Guatemala City (3.1%, 88/2834), we observed a high prevalence of precocious menarche in the city of Puerto Barrios, Izabal, Guatemala (88%, 486/551). We observed a high prevalence of precocious menarche in Puerto Barrios across all age groups. In contrast in Guatemala City, the median age at menarche declined from the age of 14 in 50-60-year-old women to 13 in women under 40 years of age. Hospital records show that the occurrence of both miscarriage and pregnancy under age 14 is substantially higher in Izabal. In addition, the main public hospital in Puerto Barrios accounts for a high fraction of the early pregnancies and miscarriages seen in Guatemala. ConclusionsIn Puerto Barrios, Izabal, Guatemala, the prevalence of menarche before age 11 is dramatically elevated compared to Guatemala City and substantially higher than other worldwide populations. We observed precocious menarche in Puerto Barrios in all age groups examined, indicating that this condition has been common for decades. This finding is supported by the comparatively higher occurrence of early pregnancy and miscarriage in Puerto Barrios compared with Guatemala City. The cause is unknown, but precocious menarche is associated with adverse reproductive outcome in young women and warrants further investigation.

epidemiology↗

bioRxiv2017

Low-Cost HPV Screening And The Prevalence Of Cervical Infection In Asymptomatic Populations In Guatemala

BackgroundA low cost and accurate method for detecting high-risk (HR) HPV is important to permit HPV testing for cervical cancer prevention. We validated a low-cost commercially available HPV method (H13, Hybribio, Hong Kong) and determined the distribution of HPV infections in over 1717 cancer-free women in Guatemala.\n\nMethodsH13 results were compared with two more established HPV tests: (Xpert (Cepheid) and SPF10-LIPA25 (DDL)) in 40 mainly known positive specimens. HR-HPV was detected in cervical samples from 1717 cancer-free women receiving Pap smears using the Hybribio realtime PCR assay of 13 HR types. Selected HPV positive samples were sequenced to determine viral type.\n\nResultsThe Hybribio H13 Assay showed 93% identical results with Xpert, and 89% with SPF10-LIPA25. A total of 13% (226/1717) of women tested HPV+. The highest prevalence was found in younger women (<30 years, 22 %) and older ones ([≥]60 years, 15%). The six most common HR-HPV types among the 148 HPV+ typed were HPV16 (22%), HPV18 (11%), HPV39 (11%), HPV58 (10%), HPV52 (8%), and HPV45 (8%).\n\nConclusionsThe Hybribio Assay was low cost, and accurate in testing for HR-HPV infection. As in most places, HPV16 was the most prevalent HR type in Guatemala and the age-specific prevalence curve peaked in younger ages.\n\nHighlightsO_LIA low cost and accurate method, Hybribio Assay, could be used for CC testing in low income regions.\nC_LIO_LIA total of 13% of cancer-free women were HPV+ and positivity was associated with younger age (<30 years old) in Guatemala.\nC_LIO_LIHPV16 was the major prevalent type.\nC_LI

molecular biology↗