Biology subjects

Soares, A. R.

Publications and source records attributed to Soares, A. R..

12 recordsLinked to original sources

bioRxiv2026

Host tRNA modifications drive efficient translation of influenza A virus genome and impact host antiviral stress responses

Influenza A virus (IAV), as all other viruses, is completely dependent on the host translation machinery components, including host transfer RNAs (tRNAs), to effectively decode its genome. However, while the human genome is biased towards cytosine (C) and guanosine (G)-ending codons, the IAV genome is skewed towards adenine (A) and uridine (U)-ending codons. Nevertheless, translation of IAVs RNA genome is highly efficient. Here we show that host tRNA and tRNA epitranscriptome dynamics are important regulators of IAV RNA translation and host antiviral responses. We show that the levels of several tRNA modifications, including 5-methylcarboxymethyluridine (mcm5U34) and 5-methoxycarbonylmethyl-2-thiouridine (mcm5s2U34), and their cognate writers, vary over the course of IAV infection. Additionally, we demonstrate that a set of tRNAs are preferentially recruited to ribosomes upon IAV infection, in line with IAV codon usage requirements. We further show that loss of ELP3, the catalytic subunit of the elongator complex, which is involved in the catalysis of mcm5U34 and of mcm5s2U34, induces tRNA hypomodifications, impairs translation of codon biased IAV genes and triggers the integrated stress response (ISR), interfering with IAV propagation. Taken together, our results uncover the relevance of host tRNAs and their modifications for optimal expression of viral genomes and host antiviral responses, setting the tRNA epitranscriptome as a promising target for the development of host-based antiviral therapies.

molecular biology↗

bioRxiv2026

Selective profiling of translationally active tRNAs and their dynamics under stress

During translation, transfer RNAs (tRNAs) deliver specific amino acids to the ribosome in a coordinated manner with the sequence encoded by the mRNA. Despite their central role in protein synthesis, their precise contribution to the modulation of translation remains poorly understood, primarily due to lack of methods to characterise tRNA abundances and their modifications from actively translating ribosomes. Here we develop tRIBO-seq, a simple and robust nanopore-based method to selectively capture ribosome-associated native tRNA populations (ribo-tRNAs) from actively translating ribosomes, providing tRNA abundance, modification and fragmentation information from a single experiment. Using tRIBO-seq, we find that ribo-tRNAs, but often not total tRNAs, are significantly altered upon stress. Notably, we find that tRNAome alterations strongly vary depending on the stress type: while viral infection and leucine deprivation leads to changes in ribo-tRNA abundances, methionine starvation causes a dramatic loss of methyl-based tRNA modifications. By contrast, we find that arsenite exposure does not alter tRNA abundances nor modification patterns, but rather causes major fragmentation events in selected subsets of ribo-tRNAs. Altogether, tRIBO-seq offers a robust and reproducible approach to map the full tRNA landscape -capturing tRNA abundance, modification and fragmentation patterns-, across both total and actively translating tRNA populations, revealing the dynamics of the tRNAome with unprecedented resolution, in a single experiment.

molecular biology↗

bioRxiv2025

Noradrenergic inputs to the basolateral amygdala have bidirectional effects on coping behavior and neuronal activity in mice

Norepinephrine (NE) signaling is disrupted in stress disorders, with insufficient NE signaling implicated in major depressive disorder and hyperactive NE signaling associated with post-traumatic stress disorder, suggesting that adequate mood regulation requires optimal NE levels. The basolateral amygdala (BLA) is a hub for stress processing and receives dense noradrenergic innervation from the locus coeruleus (LC), the primary noradrenergic nucleus in the brain. The relationship between LC activity and cognitive/behavioral function during fear conditioning has been described as an inverted U, in which moderate LC activity, and subsequent NE release, is required for adaptive coping to threats, while hyperactive LC-NE signaling drives maladaptive behavioral responses. We used fiber photometry to measure NE signaling in the mouse BLA during acute behavioral responses to escapable and inescapable stressors, and then used an optogenetic approach to stimulate the noradrenergic terminals in the BLA at different frequencies to evaluate effects on coping behavior and cFos expression in the LC-BLA circuit. We found that low-frequency stimulation of the circuit inhibited both passive coping and BLA neuronal activity, while high-frequency stimulation had the opposite effect; the behavioral effects were not mediated by sex, but the cFos effects were specific to males. This study represents an expansion of the inverted U framework to encompass LC-BLA signaling driving acute behavioral responses to stress. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=79 SRC="FIGDIR/small/677150v1_ufig1.gif" ALT="Figure 1"> View larger version (23K): org.highwire.dtl.DTLVardef@1b642a7org.highwire.dtl.DTLVardef@d20eedorg.highwire.dtl.DTLVardef@d22aa7org.highwire.dtl.DTLVardef@1ee4291_HPS_FORMAT_FIGEXP M_FIG C_FIG HighlightsO_LIBLA NE levels signal behavioral transitions between coping responses to stress C_LIO_LILow-frequency stimulation of BLA NE terminals inhibits passive coping and BLA cFos C_LIO_LIHigh-frequency stimulation of BLA NE terminals promotes passive coping and BLA cFos C_LIO_LIBehavioral effects are similar across sexes, but cFos alterations are male- specific C_LI

neuroscience↗

bioRxiv2025

Uranium mining fuels evolution in deep groundwater microbiomes

Deep-biosphere microbes have been underpinning global biogeochemical cycles throughout Earth history, yet their evolutionary responses to long-term anthropogenic disturbance remain poorly understood. Neutral-pH in-situ leaching (ISL), the dominant uranium-mining strategy, imposes persistent radiochemical and redox stress offering rare natural experiments across decades for observing subsurface microbial evolution. Here, by exploiting metagenomics and metatranscriptomics in examining microbial responses through various mining stages, we show that neutral U ISL causes substantial changes in microbial communities spanning 2,294 strains accompanied by diversification and selection of active microbial species. These changes occurred during elevated dissolved uranium and radiological activity which correlated with a substantial transcriptional change in energy metabolism, and with an overexpression of specific genes for oxidative-stress defence and DNA-repair pathways. Increased nucleotide diversity in 101 out of 392 species clusters and nonsynonymous/synonymous polymorphism ratios greater than one in 139 species clusters were predominantly observed in metatranscriptomes with elevated radiation, highlighting positive selection of transcriptionally active populations. These findings demonstrate that neutral U ISL drives functional and genetic diversification of subsurface microbiomes, revealing a dynamic and evolutionarily responsive deep biosphere.

genomics↗

bioRxiv2025

A uniform stress response of stream microbiomes in the hyporheic zone across North America

BackgroundStream hyporheic zones represent a unique ecosystem at the interface of stream water and surrounding sediments, characterized by high heterogeneity and accelerated biogeochemical activity. These zones are increasingly impacted by anthropogenic stressors and environmental changes at a global scale, directly altering their microbiomes. Despite their importance, the current body of literature lacks a systematic understanding of active nitrogen and sulfur cycling across stream sediment and surface water microbiomes, particularly across geographic locations and in response to environmental stressors. ResultsBased on previously published and unpublished datasets, 363 stream metagenomes were combined to build a comprehensive MAG and gene database from stream sediments and surface water including a full-factorial mesocosm experiment which had been deployed to unravel microbial stress response. Metatranscriptomic data from 23 hyporheic sediment samples collected across North America revealed that microbial activity in sediments was distinct from the activity in surface water, contrasting similarly encoded metabolic potential across the two compartments. The expressed energy metabolism of the hyporheic zone was characterized by increased cycling of sulfur and nitrogen compounds, governed by Nitrospirota and Desulfobacterota lineages. While core metabolic functions like energy conservation were conserved across sediments, temperature and stream order change resulted in differential expression of stress response genes previously observed in mesocosm studies. ConclusionsThe hyporheic zone is a microbial hotspot in stream ecosystems, surpassing the activity of overlaying riverine surface waters. Metabolic activity in the form of sulfur and nitrogen cycling in hyporheic sediments is governed by multiple taxa interacting through metabolic handoffs. Despite the spatial heterogeneity of streams, the hyporheic sediment microbiome encodes and expresses conserved stress responses to anthropogenic stressors, e.g., temperature, in streams of separate continents. The high number of uncharacterized differentially expressed genes as a response to tested stressors is a call-to-action to deepen the study of stream systems.

microbiology↗

bioRxiv2024

Alternative translation initiation produces synaptic organizer proteoforms with distinct localization and functions

While previous studies suggest that many mRNAs contain more than one translation initiation site (TIS), the biological significance of most alternative TISs and their corresponding protein isoforms (proteoforms) remains undetermined. Here we show that alternative translation initiation at a CUG and an AUG TIS in neuronal pentraxin receptor (NPR) mRNA produces two proteoforms, and their relative abundance is regulated by both neuronal activity as well as an adjacent RNA secondary structure. Downstream AUG initiation transforms the N-terminal transmembrane domain into a signal peptide, thereby converting NPR to a secreted factor sufficient to promote synaptic clustering of AMPA-type glutamate receptors. Changing the relative proteoform ratio, but not the overall NPR abundance reduces AMPA receptor in parvalbumin (PV)-positive interneurons and induces changes in learning behaviors in mice. In addition to NPR, N-terminal extensions of C1q-like synaptic organizers, mediated by upstream AUU start codons, anchor these otherwise secreted factors to the membrane. Thus, our results uncovered the plasticity of N-terminal signal sequences regulated by alternative TIS usage as a widespread mechanism to diversify protein localization and functions.

molecular biology↗

bioRxiv2023

Influenza A virus activates the unfolded protein response and induces the accumulation of insoluble protein aggregates that are essential for efficient viral propagation

Influenza A virus (IAV) is one of the main causes of annual respiratory epidemics in humans. IAV employs multiple strategies to evade host immunity and hijack cellular mechanisms to support proper virion formation and propagation. Some of these strategies encompass the manipulation of pathways involved in protein homeostasis, leading to changes in the host proteome and protein distribution within the cell. In this study, we performed a detailed analysis of the interplay between IAV and the host cells proteostasis mechanisms throughout the entire infectious cycle. We reveal that IAV infection induces the activation of the inositol requiring enzyme 1 (IRE1) branch of the unfolded protein response (UPR), at an infection stage that coincides with high rates of viral protein translation. This activation is particularly important for infection, as attenuation of virus production was observed upon IRE1 inhibition. Concomitantly to UPR activation, we observed the accumulation of virus-induced insoluble protein aggregates, which contain both viral and host proteins and are associated with a dysregulation of the host cell RNA metabolism. We demonstrate that this accumulation is important for IAV propagation, as its prevention using a quinoline-steroid hybrid compound significantly reduces the number of produced infectious virus particles. Our data suggests that the formation of these insoluble protein aggregates favors the final steps of the infection cycle, more specifically the virion assembly. Our findings reveal additional mechanisms by which IAV disrupts the host cell proteostasis to favor infection and uncover new cellular targets that can be explored for the development of host-directed antiviral strategies.

microbiology↗

bioRxiv2023

Amyloid pathology reduces ELP3 expression and tRNA modifications leading to impaired proteostasis in Alzheimer's disease models

Alzheimers Disease (AD) is a progressive and irreversible neurodegenerative disorder, characterized by the accumulation of abeta-amyloid aggregates, which triggers tau hyperphosphorylation and neuronal loss. While the precise mechanisms underlying neurodegeneration in AD are not entirely understood, it is known that loss of proteostasis is implicated in this process. Maintaining neuronal proteostasis requires proper transfer RNA (tRNA) modifications, which are crucial for optimal translation. However, research into tRNA epitranscriptome in AD is limited, and it is not yet clear how alterations in tRNA modifying enzymes and tRNA modifications might contribute to disease progression. Here, we report that expression of the tRNA modifying enzyme ELP3 is reduced in the brain of AD patients and amyloid AD mouse models, suggesting ELP3 is implicated in proteostasis dysregulation observed in AD. To investigate the role of ELP3 specifically in neuronal proteostasis impairments in the context of amyloid pathology, we analyzed SH-SY5Y neuronal cells carrying the amyloidogenic Swedish familial AD mutation in the APP gene (SH-SWE) or the wild-type gene (SH-WT). Similarly to the amyloid mouse models, SH-SWE exhibited reduced levels of ELP3 which was associated with tRNA hypomodifications and reduced abundance, as well as proteostasis impairments. Furthermore, the knock-down of ELP3 in SH-WT recapitulated the proteostasis impairments observed in SH-SWE cells. Importantly, the correction of tRNA deficits due to ELP3 reduction rescued and reverted proteostasis impairments of SH-SWE and SH-WT knock-down for ELP3, respectively. Additionally, SH-WT exposed to the secretome of SH-SWE or synthetic amyloid aggregates recapitulate the SH-SWE phenotype, characterized by reduced ELP3 expression, tRNA hypomodification and increased protein aggregation. Taken together, our data suggest that amyloid pathology dysregulates neuronal proteostasis through the reduction of ELP3 and tRNA modifications. This study highlights the modulation of tRNA modifications as a potential therapeutic avenue to restore neuronal proteostasis in AD and preserve neuronal function. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=112 SRC="FIGDIR/small/538928v2_ufig1.gif" ALT="Figure 1"> View larger version (44K): org.highwire.dtl.DTLVardef@ed5cf4org.highwire.dtl.DTLVardef@171b14aorg.highwire.dtl.DTLVardef@12eb19dorg.highwire.dtl.DTLVardef@8ed4ab_HPS_FORMAT_FIGEXP M_FIG C_FIG

molecular biology↗

bioRxiv2023

Dancing the Nanopore limbo - Nanopore metagenomics from small DNA quantities for bacterial genome reconstruction

BackgroundWhile genome-resolved metagenomics has revolutionized our understanding of microbial and genetic diversity in environmental samples, assemblies of short-reads often result in incomplete and/or highly fragmented metagenome-assembled genomes (MAGs), hampering in-depth genomics. Although Nanopore sequencing has increasingly been used in microbial metagenomics as long reads greatly improve the assembly quality of MAGs, the recommended DNA quantity usually exceeds the recoverable amount of DNA of environmental samples. Here, we evaluated lower-than-recommended DNA quantities for Nanopore library preparation by determining sequencing quality, community composition, assembly quality and recovery of MAGs. ResultsWe generated 27 Nanopore metagenomes using the commercially available ZYMO mock community and varied the amount of input DNA from 1000 ng (the recommended minimum) down to 1 ng in eight steps. The quality of the generated reads remained stable across all input levels. The read mapping accuracy, which reflects how well the reads match a known reference genome, was consistently high across all libraries. The relative abundance of the species in the metagenomes was stable down to input levels of 50 ng. High-quality MAGs (> 95% completeness, [≤] 5% contamination) could be recovered from metagenomes down to 35 ng of input material. When combined with publicly available Illumina reads for the mock community, Nanopore reads from input quantities as low as 1 ng improved the quality of hybrid assemblies. ConclusionOur results show that the recommended DNA amount for Nanopore library preparation can be substantially reduced without any adverse effects to genome recovery and still bolster hybrid assemblies when combined with short-read data. We posit that the results presented herein will enable studies to improve genome recovery from low-biomass environments, enhancing microbiome understanding.

microbiology↗

bioRxiv2022

ACh signaling modulates activity of the GABAergic signaling network in the basolateral amygdala and behavior in stress-relevant paradigms.

Balance between excitatory and inhibitory (E/I) signaling is important for maintaining homeostatic function in the brain. Indeed, dysregulation of inhibitory GABA interneurons in the amygdala has been implicated in human mood disorders. We hypothesized that acetylcholine (ACh) signaling in the basolateral amygdala (BLA) might alter E/I balance resulting in changes in stress-sensitive behaviors. We therefore measured ACh release as well as activity of calmodulin-dependent protein kinase II (CAMKII)-, parvalbumin (PV)-, somatostatin (SOM)- and vasoactive intestinal protein (VIP)-expressing neurons in the BLA of awake, behaving mice. ACh levels and activity of both excitatory and inhibitory BLA neurons increased when animals were actively coping, and decreased during passive coping, in the light-dark box, tail suspension and social defeat. Changes in neuronal activity preceded behavioral state transitions, suggesting that BLA activity may drive the shift in coping strategy. In contrast to exposure to escapable stressors, prolonging ACh signaling with a cholinesterase antagonist changed the balance of activity among BLA cell types, significantly increasing activity of VIP neurons and decreasing activity of SOM cells, with little effect on CaMKII or PV neurons. Knockdown of 7 or {beta}2-containing nAChR subtypes in PV and SOM, but not CaMKII or VIP, BLA neurons altered behavioral responses to stressors, suggesting that ACh signaling through nAChRs on GABA neuron subtypes contributes to stress-induced changes in behavior. These studies show that ACh modulates the GABAergic signaling network in the BLA, shifting the balance between SOM, PV, VIP and CaMKII neurons, which are normally activated coordinately during active coping in response to stress. Thus, prolonging ACh signaling, as occurs in response to chronic stress, may contribute to maladaptive behaviors by shifting the balance of inhibitory signaling in the BLA.

neuroscience↗

bioRxiv2021

Integration of differential gene expression with weighted gene correlation network analysis identifies genes whose expression is remodeled throughout physiological aging in mouse tissues

Gene expression alterations occur in all mouse tissues during aging, but recent works highlight minor rather than major dysregulation amplitude for most genes, questioning whether differentially expressed genes on their own provide deep insight into aging biology. To clarify this issue, we have combined differential gene expression with weighted gene correlation network analysis (WGCNA) to identify expression signatures accounting for the pairwise relations between gene expression profiles and the cumulative effect of genes with small fold- changes during aging in the brain, heart, liver, skeletal muscle, and pancreas of C57BL/6 mice. Functional enrichment analysis of the overlap of genes identified in both approaches showed that immunity-related responses, mitochondrial energy metabolism, tissue regeneration and detoxification are prominently altered in the brain, heart, muscle, and liver, respectively, reflecting an age-related global loss of tissue function. While data showed little overlap among the age-dysregulated genes between tissues, aging triggered common biological processes in distinct tissues, particularly proteostasis-related pathways, which we highlight as important features of murine tissue physiological aging.

genetics↗

bioRxiv2020

tRNA-modifying enzyme mutations induce codon-specific mistranslation and protein aggregation in yeast

Abstract/SummaryProtein synthesis rate and accuracy are essential for bona fide protein synthesis and proteome homeostasis (proteostasis), however the mRNA translation elongation factors that prevent protein mistranslation, misfolding and aggregation are poorly understood. To address this question, we evaluated the role of 70 yeast tRNA modifying enzyme genes on protein aggregation and used mass spectrometry to identify the aggregated and mistranslated proteins. We show that the mitochondrial tRNA-modifying enzyme Slm3 thiolates the cytoplasmic tRNAs at position 34 and that decreased levels of mcm5s2U34 in SLM3 mutants are compensated by increasing mcm5U34, ncm5U34 and ncm5Um34 levels. In the tRNA gene knockout strains, stress response proteins are overrepresented in protein aggregates and their genes are enriched in codons decoded by tRNAs lacking mcm5U34, mcm5s2U34, ncm5U34, ncm5Um34, modifications. Increased rates of amino acid misincorporation were detected in the yeast ELP1, SLM3 and TRM9 gene knockout mutants at protein sites that specifically mapped to the codons sites that are decoded by the hypomodified tRNAs, demonstrating that U34 tRNA modifications safeguard the proteome from translational errors, misfolding and cellular proteotoxic stress.

molecular biology↗