Biology subjects

Couture, L.

Publications and source records attributed to Couture, L..

4 recordsLinked to original sources

bioRxiv2025

Oropouche virus infects human neural progenitor cells and alters the growth of brain organoids

Oropouche virus (OROV), is the etiologic agent of Oropouche fever (OROF), an emerging zoonotic disease that has been prevalent in South and Central America since the 1960s. Starting late 2023, the current outbreak has raised concern about vertical transmission and potential adverse pregnancy outcomes. While serological evidences and recent studies support the vertical transmission of OROV, how infection affects the fetal brain remains unclear. Here we show that a strain of OROV, FG_2020, phylogenetically-related to the epidemic strain, efficiently and productively infects human neural progenitor cells and iPSC-derived brain organoids. The main phenotypic effect is proliferation arrest associated with apoptosis leading to the loss of neural rosette organization, a key signature of developing brain architecture. These data indicates that fetal brain is susceptible to OROV infection and that vertical transmission during the first months of pregnancy could lead to pathological effects on brain development.

microbiology↗

bioRxiv2024

Serum metabolome profiling in patients with mild cognitive impairment reveals sex differences in lipid metabolism

Alzheimers disease (AD) affects more women than men. Although women live longer than men, it is not longevity alone, but other factors, including metabolic changes, that contribute to the higher risk of AD in women. Metabolic pathways have been implicated in AD progression, but studies to date examined targeted pathways, leaving many metabolites unmeasured. Sex is often a neglected biological variable, and most metabolomic studies were not designed to investigate sex differences in metabolomic profiles. Here, we performed untargeted metabolomic profiling of sera from male and female patients with mild cognitive impairment (MCI), a common precursor to AD, and matched controls. We discovered significant metabolic changes in individuals with MCI, and found several pathways that were strongly associated with sex. Peptide energy metabolism demonstrated sexual dimorphism. Lipid pathways exhibited the strongest differences between female and male MCI patients, including specific phosphatidylcholine lipids, lysophospholipids, long-chain fatty acids, and monoacylglycerols. 1-palmitoleoyl glycerol and 1-arachidonoyl glycerol were higher in female MCI subjects than in male MCI subjects with no differences between control males and females. Conversely, specific dicarboxylic fatty acids were lower in female MCI subjects than male MCI subjects. In cultured astrocytes, 1-arachidonoyl glycerol promoted phosphorylation of the transcriptional regulator sphingosine kinase 2, which was inhibited by the transient receptor potential vanilloid 1 receptor antagonists, as well as chromatin remodelling. Overall, we identified novel sex-specific metabolites in MCI patients that could serve as biomarkers of MCI in both sexes, help further define AD etiology, and reveal new potential prevention strategies for AD. Highlights{blacksquare} Individuals with MCI experience significant metabolic changes. {blacksquare}Lipid pathways demonstrated the strongest sexual dimorphism in MCI. {blacksquare}1-monoacylglycerols showed a robust sex association, being higher in MCI females. {blacksquare}Sex-specific metabolites may be MCI biomarkers in each sex.

neuroscience↗

bioRxiv2023

Probiotic Lactobacillus strains decrease the susceptibility of Salmonella Typhimurium to the last resort antibiotic azithromycin.

Bacteria are involved in numerous interactions during infection and among host-associated microbial populations. Salmonella enterica serovar Typhimurium is a foodborne pathogen of great importance as well as a model organism to study interactions within a microbial community. In this study, we found that S. Typhimurium becomes tolerant to azithromycin when co-cultured with strains of Lactobacillus. Similarly, acidified media, from cell-free supernatant of Lactobacillus cultures for instance, also induced the tolerance of S. Typhimurium to azithromycin. The addition of membrane disruptors restored the normal sensitivity to azithromycin in acidified media, but not when Lactobacillus was present. These results suggested that the acidification of the media led to modification in envelope homeostasis, but that a different mechanism promoted the tolerance to azithromycin in the presence of Lactobacillus strains. To further understand how Lactobacillus strains modify the sensitivity of S. Typhimurium to azithromycin, a high-throughput assay was carried using the single gene deletion collection of the S. Typhimurium (1) in coculture with L. rhamnosus and (2) in sterile acidic conditions (pH 5.5 media only). As expected, both screens identified genes involved in envelope homeostasis and membrane permeability. Our results also suggest that changes in the metabolism of S. Typhimurium induce the tolerance observed in the presence of L. rhamnosus. Our results thus highlight two different mechanisms by which Lactobacillus strains induce tolerance of S. Typhimurium to antibiotics. ImportanceThis study provides valuable insights into the intricate interactions between bacteria during infections and within host-associated microbial communities. Specifically, it sheds light on the significant role of Lactobacillus strains in inducing antibiotic tolerance in Salmonella enterica serovar Typhimurium, a critical foodborne pathogen and model organism for microbial community studies. The findings not only uncover the mechanisms underlying this antibiotic tolerance but also reveal two distinct pathways through which Lactobacillus strains might influence Salmonellas response to antibiotics. Understanding these mechanisms has the potential to enhance our knowledge of bacterial infections and may have implications for the development of strategies to combat antibiotic resistance in pathogens like Salmonella. Furthermore, our results underscore the necessity to explore beyond the direct antimicrobial effects of antibiotics, emphasizing the broader microbial community context.

microbiology↗

bioRxiv2021

RACK1 associates with RNA-binding proteins Vigilin and SERBP1 to control dengue virus replication

Dengue virus (DENV), a re-emerging virus transmitted by Aedes mosquitoes, causes severe pathogenesis in humans. No effective treatment is available against this virus. We recently identified the scaffold protein RACK1 as a component of the DENV replication complex, a macromolecular complex essential for viral genome amplification. Here, we show that RACK1 is important for DENV infection. RACK1 mediates DENV replication through binding to the 40S ribosomal subunit. Mass spectrometry analysis of RACK1 partners coupled to a loss-of-function screen identified the RNA binding proteins Vigilin and SERBP1 as DENV host dependency factors. Vigilin and SERBP1 interact with DENV viral RNA (vRNA), forming a ternary complex with RACK1 to mediate viral replication. Overall, our results indicate that RACK1 recruits Vigilin and SERBP1, linking the DENV vRNA to the translation machinery for optimal translation and replication.

microbiology↗