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  • Proceedings of the National Academy of Sciences  (2)
  • Biology  (2)
  • 1
    In: Proceedings of the National Academy of Sciences, Proceedings of the National Academy of Sciences, Vol. 119, No. 16 ( 2022-04-19)
    Abstract: Muco-obstructive lung diseases are typically associated with high risks of COVID-19 severity; however, allergic asthma showed reduced susceptibility. To investigate viral spread, primary human airway epithelial (HAE) cell cultures were infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), and host–virus interactions were examined via electron microscopy, immunohistochemistry, RNA in situ hybridization, and gene expression analyses. In HAE cell cultures, angiotensin-converting enzyme 2 (ACE2) expression governed cell tropism and viral load and was up-regulated by infection. Electron microscopy identified intense viral egress from infected ciliated cells and severe cytopathogenesis, culminating in the shedding of ciliated cells packed with virions, providing a large viral reservoir for spread and transmission. Intracellular stores of MUC5AC, a major airway mucin involved in asthma, were rapidly depleted, likely to trap viruses. To mimic asthmatic airways, HAE cells were treated with interleukin-13 (IL-13), which reduced viral titers, viral messenger RNA, and cell shedding, and significantly diminished the number of infected cells. Although mucus hyperproduction played a shielding role, IL-13–treated cells maintained a degree of protection despite the removal of mucus. Using Gene Expression Omnibus databases, bulk RNA-sequencing analyses revealed that IL-13 up-regulated genes controlling glycoprotein synthesis, ion transport, and antiviral processes (albeit not the typical interferon-induced genes) and down-regulated genes involved in cilial function and ribosomal processing. More precisely, we showed that IL-13 reduced ACE2 expression, intracellular viral load, and cell-to-cell transmission while increasing the cilial keratan sulfate coating. In conclusion, intense viral and cell shedding caused by SARS-CoV-2 infection was attenuated by IL-13, which affected viral entry, replication, and spread.
    Type of Medium: Online Resource
    ISSN: 0027-8424 , 1091-6490
    RVK:
    RVK:
    Language: English
    Publisher: Proceedings of the National Academy of Sciences
    Publication Date: 2022
    detail.hit.zdb_id: 209104-5
    detail.hit.zdb_id: 1461794-8
    SSG: 11
    SSG: 12
    Location Call Number Limitation Availability
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  • 2
    In: Proceedings of the National Academy of Sciences, Proceedings of the National Academy of Sciences, Vol. 117, No. 21 ( 2020-05-26), p. 11703-11714
    Abstract: Patients with hematological malignancies or undergoing hematopoietic stem cell transplantation are vulnerable to colonization and infection with multidrug-resistant organisms, including vancomycin-resistant Enterococcus faecium (VREfm). Over a 10-y period, we collected and sequenced the genomes of 110 VREfm isolates from gastrointestinal and blood cultures of 24 pediatric patients undergoing chemotherapy or hematopoietic stem cell transplantation for hematological malignancy at St. Jude Children’s Research Hospital. We used patient-specific reference genomes to identify variants that arose over time in subsequent gastrointestinal and blood isolates from each patient and analyzed these variants for insight into how VREfm adapted during colonization and bloodstream infection within each patient. Variants were enriched in genes involved in carbohydrate metabolism, and phenotypic analysis identified associated differences in carbohydrate utilization among isolates. In particular, a Y585C mutation in the sorbitol operon transcriptional regulator gutR was associated with increased bacterial growth in the presence of sorbitol. We also found differences in biofilm-formation capability between isolates and observed that increased biofilm formation correlated with mutations in the putative E. faecium capsular polysaccharide ( cps ) biosynthetic locus, with different mutations arising independently in distinct genetic backgrounds. Isolates with cps mutations showed improved survival following exposure to lysozyme, suggesting a possible reason for the selection of capsule-lacking bacteria. Finally, we observed mutations conferring increased tolerance of linezolid and daptomycin in patients who were treated with these antibiotics. Overall, this study documents known and previously undescribed ways that VREfm evolve during intestinal colonization and subsequent bloodstream infection in immunocompromised pediatric patients.
    Type of Medium: Online Resource
    ISSN: 0027-8424 , 1091-6490
    RVK:
    RVK:
    Language: English
    Publisher: Proceedings of the National Academy of Sciences
    Publication Date: 2020
    detail.hit.zdb_id: 209104-5
    detail.hit.zdb_id: 1461794-8
    SSG: 11
    SSG: 12
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
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