Biology subjects

Araya, P.

Publications and source records attributed to Araya, P..

4 recordsLinked to original sources

bioRxiv2026

Altered follicular immunity in secondary lymphoid organs is associated with interferon hyperactivity in Down syndrome

Down syndrome, caused by trisomy 21, is characterized by chronic interferon-associated inflammation and immune dysregulation, yet the contribution of human secondary lymphoid organs to shaping this immune landscape remains unclear. Using multimodal single-cell and spatial profiling of human tonsils, we identify extensive remodeling of immune organization in trisomy 21. CD4 T cells are skewed away from canonical follicular helper (TFH) programs toward inflammatory TFH1-like and cytotoxic helper states enriched for interferon-responsive transcriptional programs. Tonsillar TFH cells exhibit increased interferon-{gamma} and interleukin-21 production, indicating inflammatory skewing toward type 1 helper immunity. These alterations are accompanied by changes in dendritic cell and CD8 T-cell compartments, reduced follicular size, increased extrafollicular TFH1-B-cell proximity and altered B-cell differentiation trajectories. Together, our findings identify trisomy 21 as a unique human context to investigate how chronic interferon-associated inflammation reshapes lymphoid tissue organization and adaptive immune cell fate decisions.

immunology↗

bioRxiv2022

Population genomics, resistance, pathogenic potential, and mobile genetic elements of carbapenem-resistant Klebsiella pneumoniae causing infections in Chile

Multidrug and carbapenem-resistant K. pneumoniae (CR-Kp) are considered critical threats to global health and key traffickers of resistance genes to other pathogens. In Chile, although a sustained increase in CR-Kp infections has been observed, few strains have been described at the genomic level, lacking molecular details of their resistance and virulence determinants and the mobile elements mediating their dissemination. In this work, we studied the antimicrobial resistance and performed a comparative genomics analysis of ten CR-Kp isolates from the Chilean surveillance of carbapenem-resistant Enterobacteriaceae. High resistance to most of the antibiotics tested was observed among the isolates, five ST25, three ST11, one ST45, and one ST505, which harbored a total of 44 plasmids, many of them predicted to be conjugative and carrying genes conferring resistance to a variety of antibiotic, metals, and disinfectants. Ten plasmids encoding either KPC-2, NDM-1, or NDM-7 carbapenemases were characterized, including novel plasmids with increased resistance gene load and a novel genetic environment for blaKPC-2 gene. This corresponds to the first report of ST25 and ST45 Kp producing NDM-7 in South America, and of an ST505 CR-Kp worldwide, producing both NDM-7 and KPC-2. Moreover, we characterized a variety of genomic islands carrying virulence and fitness factors. These results provide baseline knowledge for the detailed understanding of molecular and genetic determinants behind antibiotic resistance and virulence of K. pneumoniae in Chile and South America.

microbiology↗

bioRxiv2022

Interferon receptor gene dosage determines multiple hallmarks of Down syndrome

Trisomy 21 causes Down syndrome, a condition characterized by cognitive impairments, immune dysregulation, and atypical morphogenesis. Using whole blood transcriptome analysis, we demonstrate that specific overexpression of four interferon receptors encoded on chromosome 21 associates with chronic interferon hyperactivity and systemic inflammation in Down syndrome. To define the contribution of interferon receptor overexpression to Down syndrome phenotypes, we used genome editing to correct interferon receptor gene dosage in mice carrying triplication of a large genomic region orthologous to human chromosome 21. Normalization of interferon receptor copy number attenuated lethal antiviral responses, prevented heart malformations, decreased developmental delays, improved cognition and normalized craniofacial anomalies. Therefore, interferon receptor gene dosage determines major hallmarks of Down syndrome, indicating that trisomy 21 elicits an interferonopathy amenable to therapeutic intervention. One-Sentence SummaryCorrection of interferon receptor gene dosage rescues multiple key phenotypes in a mouse model of trisomy 21.

genetics↗

bioRxiv2020

JAK1 inhibition blocks lethal sterile immune responses:implications for COVID-19 therapy

Cytokine storms are drivers of pathology and mortality in myriad viral infections affecting the human population. In SARS-CoV-2-infected patients, the strength of the cytokine storm has been associated with increased risk of acute respiratory distress syndrome, myocardial damage, and death. However, the therapeutic value of attenuating the cytokine storm in COVID-19 remains to be defined. Here, we report results obtained using a novel mouse model of lethal sterile anti-viral immune responses. Using a mouse model of Down syndrome (DS) with a segmental duplication of a genomic region encoding four of the six interferon receptor genes (Ifnrs), we demonstrate that these animals overexpress Ifnrs and are hypersensitive to IFN stimulation. When challenged with viral mimetics that activate Toll-like receptor signaling and IFN anti-viral responses, these animals overproduce key cytokines, show exacerbated liver pathology, rapidly lose weight, and die. Importantly, the lethal immune hypersensitivity, accompanying cytokine storm, and liver hyperinflammation are blocked by treatment with a JAK1-specific inhibitor. Therefore, these results point to JAK1 inhibition as a potential strategy for attenuating the cytokine storm and consequent organ failure during overdrive immune responses. Additionally, these results indicate that people with DS, who carry an extra copy of the IFNR gene cluster encoded on chromosome 21, should be considered at high risk during the COVID-19 pandemic. One Sentence SummaryInhibition of the JAK1 kinase prevents pathology and mortality caused by a rampant innate immune response in mice.

immunology↗