Biology subjects

Aguiar, R. S.

Publications and source records attributed to Aguiar, R. S..

5 recordsLinked to original sources

bioRxiv2026

Integrated multiomic profiling of SCN2A loss-of-function reveals widespread molecular remodeling in patient hiPSC-derived neurons

SCN2A-related neurodevelopmental disorders comprise a genetically and mechanistically diverse group of early-onset brain conditions. Loss-of-function (LoF) variants in SCN2A represent one of the strongest genetic risk factors for autism spectrum disorder and intellectual disability, yet the molecular cascade linking reduced NaV1.2 dosage to neuronal dysfunction remains poorly understood. Here, we combine deep isoform-resolved transcriptomics, high-content imaging, and high-content cellular phenotyping in human hiPSC-derived neurons from three unrelated individuals carrying pathogenic SCN2A LoF variants and three independent healthy donor lines to delineate the multi-layered consequences of NaV1.2 insufficiency. We show that SCN2A LoF activates the nonsense-mediated decay (NMD) mechanism, selectively depleting canonical SCN2A isoforms and modifying the cells RNA processing. These molecular deficits translate into robust structural phenotypes, including axon initial segment shortening, reduced sodium channel density, and simplified dendritic arborization. Transcriptomic analysis converged on remodeling of synaptic and axonal pathways. RNA-seq identified coordinated alterations in gene programs linked to synaptic signaling, ion channel activity, and neuronal projection development, consistent with the structural and functional phenotypes observed. Transcript-level analysis further uncovered extensive perturbation of long non-coding RNA (lncRNA) networks, including lncRNAs strongly correlated with SYN1 and ANK3 isoforms. Together, these findings reveal that SCN2A haploinsufficiency induces a phenotype spanning NMD activation, isoform-specific dysregulation, axon initial segment destabilization and lncRNA-dependent regulatory shifts. This multiscale framework clarifies how reduced NaV1.2 disrupts neuronal development and highlights isoform-level restoration and modulation of post-transcriptional control as promising therapeutic avenues for SCN2A-related neurodevelopmental disorders.

neuroscience↗

bioRxiv2025

Microcephaly-like phenotype triggered by novel reassortant and prototypic Oropouche Virus strains in brain organoids

Oropouche virus (OROV) is an emerging arbovirus currently spreading across South America, with increasing reports of neurological manifestations, severe systemic disease, and congenital abnormalities. Although traditionally associated with mild febrile illness, the recent geographic expansion and surge in OROV outbreaks have prompted attention to its neurotropic potential. Here, we investigated the impact of OROV infection on human neural development using neural stem cells (NSCs) and brain organoids derived from induced pluripotent stem cells. Recent OROV isolates exhibiting genomic reassortment and associated with increased neurological manifestations were compared with a prototypical strain for the ability to infect NSCs, early-stage organoids, and more mature cortical-like tissues. OROV infected NSCs efficiently, leading to widespread cell death, depletion of proliferative progenitors, and disruption of neuroepithelial organization. Transcriptomic profiling of infected NSCs revealed a robust reduction of antiviral response genes and an enrichment of pathways related to viral replication, apoptosis, and the inhibition of stem cell maintenance and neuronal differentiation. These molecular signatures aligned with the phenotypic collapse of progenitor pools and cortical structure observed in organoids. OROV antigens were detected in both astrocytes and neurons, with associated structural degeneration. Although a substantial overlap in differentially expressed genes was observed between the two viral strains, some strain-specific transcriptional responses were detected. However, these modest differences did not translate into distinct cytopathogenic effects between the two viral strains. These phenotypes, including the reduced growth of infected organoids, resemble those previously described with Zika virus in the same cellular models, supporting the hypothesis that OROV may impair brain development. Together, these results reveal a previously unrecognized neuroteratogenic potential of OROV strains and provide mechanistic insight into the potential of OROV to induce microcephaly-like phenotypes, highlighting its relevance as a significant threat to maternal-fetal health.

neuroscience↗

bioRxiv2023

Lessons from a multilaboratorial task force for diagnosis of a fatal toxoplasmosis outbreak in captive primates in Brazil

As exemplified by the Coronavirus Disease 2019 (COVID-19) pandemic, infectious diseases may emerge and spread rapidly, often causing serious economic losses and public health concerns. In fact, disease outbreaks have become increasingly common, especially those of zoonotic origin. The Brazilian Ministry of Health is responsible for national epizootic surveillance. However, the systems focus primarily on diseases affecting humans has led to the neglect of other zoonotic diseases. In this report, we present an integrated investigation of an outbreak that occurred during the first year of the COVID-19 pandemic among captive neotropical primates housed at a primatology center in Brazil. After presenting a range of non-specific clinical signs, including fever, prostration, inappetence, and abdominal pain, ten primates from five different species died within approximately four days. Despite the state of health emergency due to the pandemic, a network of volunteer researchers was established to investigate the outbreak. A wide range of high-resolution techniques was used for different pathogens, including SARS-CoV-2 (RTq-PCR, ELISA and IHC), Toxoplasma gondii (IHC and IFA) and Escherichia coli (IFA), as well as a portable Metagenomic Sequencing utilizing Nanopore Technology. Within a span of four days after necropsies, we successfully identified T. gondii as the causative agent of this outbreak. This case highlights some of the obstacles faced with the current Brazilian surveillance system, which is still limited. A cross-platform interdisciplinary investigation could be a possible model for future epizootic investigations in non-human animals. Author summaryThe Brazilian epizootic surveillance system, under the regulation of the Ministry of Health, has been established to address a national list of compulsory notifiable diseases. However, focusing mainly on the risks to humans causes other zoonoses to be neglected. Here we present an outbreak that occurred during the first year of the COVID-19 pandemic that affected eleven neotropical primates (NP) belonging to six different species. Within four days of exhibiting a range of non-specific clinical signs, including fever, prostration, inappetence, and abdominal pain, ten NPs died. Despite testing negative for pathogens included in the national surveillance policy, a collaborative group of researchers investigated the outbreak in detail. Using integrated diagnostic techniques, we identified Toxoplasma gondii as the causative agent four days after necropsy. Toxoplasmosis causes devastating acute death outbreaks in neotropical primates and is currently absent in the national guidelines. This unified effort proved the effectiveness of a multidisciplinary collaborative surveillance network in facilitating precise diagnoses.

microbiology↗

bioRxiv2019

Genomic Surveillance of Yellow Fever Virus Epidemic Waves in Sao Paulo, Brazil, 2017 - 2018

Sao Paulo (SP), a densely inhabited state in southeast Brazil that contains the fourth most populated city in the world, recently experienced its largest yellow fever virus (YFV) outbreak in decades. YFV does not normally circulate extensively in SP, so most people were unvaccinated when the outbreak began. Surveillance in non-human primates (NHPs) is important for determining the magnitude and geographic extent of an epizootic, thereby helping to evaluate the risk of YFV spillover to humans. Data from infected NHPs can give more accurate insights into YFV spread than when using data from human cases alone. To contextualise human cases, identify epizootic foci and uncover the rate and direction of YFV spread in SP, we generated and analysed virus genomic data and epizootic case data from NHP in SP. We report the occurrence of three spatiotemporally distinct phases of the outbreak in SP prior to February 2018. We generated 51 new virus genomes from YFV positive cases identified in 23 different municipalities in SP, mostly sampled from non-human primates between October 2016 and January 2018. Although we observe substantial heterogeneity in lineage dispersal velocities between phylogenetic branches, continuous phylogeographic analyses of generated YFV genomes suggest that YFV lineages spread in Sao Paulo state at a mean rate of approximately 1km per day during all phases of the outbreak. Viral lineages from the first epizootic phase in northern Sao Paulo subsequently dispersed towards the south of the state to cause the second and third epizootic phases there. This alters our understanding of how YFV was introduced into the densely populated south of SP state. Our results shed light on the sylvatic transmission of yellow fever in highly fragmented forested regions in SP state and highlight the importance of continued surveillance of zoonotic pathogens in sentinel species. Authors SummarySince July 2016, the southeast region of Brazil has experienced the largest yellow fever virus (YFV) outbreak in decades. Sao Paulo is the most densely populated state in southeast Brazil. The outbreak has caused serious public health concern in the state, as YFV does not normally circulate widely there and most of the 21 million inhabitants were correspondingly unvaccinated against YFV when the outbreak began. In Brazil, YFV typically circulates among non-human primates, and human cases represent isolated spillover events from this predominantly sylvatic cycle. Understanding the epidemiological dynamics and spread of YFV in non-human primates is therefore critical for contextualising human cases, and guiding vaccination strategies that can better protect local human populations. Here, we aim to contextualise human cases, identify epizootic foci and uncover the rate and direction of YFV spread in SP. We analyse the geographic and temporal distribution of observed cases of YFV in non-human primates in Sao Paulo state, and identify three distinct phases of the epizootic. We generate sequence data from 51 YFV-positive cases and perform phylogenetic and phylogeographic analyses aimed at understanding the spatial spread of YFV in Sao Paulo state. Analyses of these data indicate that YFV spread from the north of Sao Paulo state into more densely populated southern regions. Although we observe substantial heterogeneity in the rate at which different sampled YFV lineages spread, the typical rate of spread was low with a mean rate of ~1 km per day. This is consistent with a scenario in which the majority of transmission events occurred between non-human primates and sylvatic vectors across forested patches. Article Summary LineGenomic surveillance of yellow fever in Sao Paulo during the 2016-2018 epizootic

epidemiology↗

bioRxiv2019

The potential role of collagens in congenital Zika syndrome: A systems biology approach

Zika virus (ZIKV) infection during pregnancy could cause a set of severe abnormalities in the fetus known as congenital Zika syndrome (CZS). Experiments using animal models and in vitro systems significantly contributed to our understanding of the physiopathology of ZIKV infection. However, the molecular basis of CZS is not yet studied in humans. Here, we used a systems biology approach to integrate transcriptomic, proteomic and genomic data from post-mortem brains of neonates with CZS. We observed that collagen genes were greatly reduced in CZS brains at both the RNA and protein levels and that neonates with CZS have several polymorphisms in collagen genes associated with osteogenesis imperfect and arthrogryposis. These findings were validated using immunohistochemistry and collagen staining of ZIKV infected and non-infected samples. Additionally, it was found that cell adhesion genes that are essential for neurite outgrowth and axon guidance were up-regulated and thereby confirmed the neuronal migration defects observed. This work provided new insights into the underlying mechanisms of CZS and revealed host genes associated with CZS susceptibility.

systems biology↗