Project description:This longitudinal scRNA-seq analysis examines age-related differences, focusing particularly on the B cell response, between young-adult and aged ferrets during SFTSV infection.
Project description:Severe fever with thrombocytopenia syndrome phlebovirus (SFTSV), listed in the WHO most dangerous pathogens, has 12-30% fatality rates with a characteristic thrombocytopenia syndrome. With a majority of clinically diagnosed SFTSV patients older than ~50 years, age is a critical risk factor for SFTSV morbidity and mortality. Here, we report an age-dependent ferret model of SFTSV infection and pathogenesis that fully recapitulates the clinical manifestations of human infections. While young adult ferrets (≤2 years old) did not show any clinical symptoms and mortality, SFTSV-infected aged ferrets (≥4 years old) demonstrated severe thrombocytopenia, reduced white blood cells, and high fever with 93% mortality rate. Moreover, significantly higher viral load was observed in aged ferrets. Transcriptome analysis of SFTSV-infected young ferrets revealed strong interferon-mediated anti-viral signaling, whereas inflammatory immune responses were markedly upregulated and persisted in aged ferrets. Thus, this immunocompetent age-dependent ferret model should be useful for anti-SFTSV therapy and vaccine development.
Project description:While the seroprevalence of SARS-CoV-2 in healthy people does not differ significantly among age groups, those aged 65 years or older exhibit strikingly higher COVID-19 mortality compared to younger individuals. To further understand differing COVID-19 manifestations in patients of different ages, three age groups of ferrets are infected with SARS-CoV-2. Although SARS-CoV-2 is isolated from all ferrets regardless of age, aged ferrets (≥3 years old) shows higher viral loads, longer nasal virus shedding, and more severe lung inflammatory cell infiltration and clinical symptoms compared to juvenile (≤6 months) and young adult (1-2 years) groups. Furthermore, direct contact ferrets co-housed with the virus-infected aged group shed more virus than direct-contact ferrets co-housed with virus-infected juvenile or young adult ferrets. Transcriptome analysis of aged ferret lungs reveals strong enrichment of gene sets related to type I interferon, activated T cells, and M1 macrophage responses, mimicking the gene expression profile of severe COVID-19 patients. Thus, SARS-CoV-2-infected aged ferrets highly recapitulate COVID-19 patients with severe symptoms and are useful for understanding age-associated infection, transmission, and pathogenesis of SARS-CoV-2.
Project description:Adult female and aged male ferrets were inefcted with SARS-CoV-2. Nasal turbinates, the right cranial lung, and right caudal lung were collected on Day 2, 7, 14, and 21 after infection. Tissues were collected from uninfected animals as control. RNA was isolated and used for analysis of the transcriptome to determine any effects on gene regulation during SARS-CoV-2 infection from age or sex.
Project description:To identify molecular characteristics of young and aged lungs post-influenza infection, we isolated RNA from lungs 60 days post-infection and examined by bulk RNAseq. We found a large number of genes remain upregulated in aged compared to young lungs. Comparison with expression of immune system-related genes from Nanostring expriments indicated this was largely infection-induced rather than baseline differences between age. This indicates that aged lungs fail to return to homeostasis following a viral respiratory infection
Project description:We carried out a global survey of age-related changes in mRNA levels in the C57BL/6NIA mouse hippocampus and found a difference in the hippocampal gene expression profile between 2-month-old young mice and 15-month-old middle-aged mice correlated with an age-related cognitive deficit in hippocampal-based explicit memory formation. Middle-aged mice displayed a mild but specific deficit in spatial memory in the Morris water maze. Keywords: age comparison
Project description:Purpose of this experiment was to study the host-transcriptional response to MA-15, MA-15epsilon, and MA-15-gamma in both young and aged mice to further understand the differences between response within each age group, and the age-related differences in response to each virus. Young (8 weeks old) and aged (1 year old) female BALB/c mice were intranasally infected with 10^5 PFU of either MA15, MA15 gamma, MA15 epsilon, or phosphate buffer solution (PBS; mock-infection). Lungs from aged mice were harvested at 12, 24, and 48 hours post-infection. Lungs from young mice were harvested at 12, 24, 48, and 96 hours post-infection. For the aged mice, 3 biological replicates were collected for microarray analysis at each time point from the infected groups. 3 mocks at 12h, 2 mocks each at 24 and 48h time points.For the young mice, 4 biological replicates were collected for microarray analysis at each time point from the infected groups.
Project description:Older adults have diminished immune responses that increase susceptibility to infectious diseases, such as influenza (flu). In older adults, flu infection can lead to hospitalization, catastrophic disability, and mortality. We previously demonstrated severe and prolonged muscle degradation and atrophy in aged mice during flu infection. Here, we utilized an unbiased transcriptomic analysis to elucidate mechanisms of flu-induced muscular declines in a mouse model. Our results showed age-related gene expression differences including downregulation of genes associated with muscle regeneration and organization and upregulation of genes associated with pro-inflammatory cytokines and migratory immune pathways in aged mice when compared to young. Pathway analysis revealed significant enrichment of leukocyte migration and T cell activation pathways in the aged muscle during infection. Intramuscular CD4 T cells increased in both young and aged mice during infection, while intramuscular CD8 T cells increased exclusively in aged muscle. CD4 T cells in young muscle were regulatory T cells (Treg), while those in aged were T follicular helper (Tfh) and Th2 cells. Correspondingly, IL-33, an important cytokine for Treg accumulation within tissue, increased only in young flu-infected muscle. Conversely, CXCL10 (IP-10) increased only in aged muscle suggesting a continued recruitment of CD8 T cells into the aged muscle during flu infection. Overall, our findings elucidate a link between flu-induced disability and dysregulated intracellular T cell recruitment into flu-injured muscle with aging. Furthermore, we uncovered potential pathways involved that can be targeted to develop preventative and therapeutic interventions to avert disability and maintain independence following infection.
Project description:Background: Type I interferons (IFNs) are essential to the clearance of viral diseases, in part by initiating upregulation of IFN regulated genes (IRGs). A clear distinction between genes upregulated directly by virus and genes upregulated by secondary IFN production has not been made. Here we investigated the genes regulated by IFN-a2b compared to the genes regulated by SARS-CoV infection in ferrets. Methods: We characterized early host immune responses in peripheral blood and lung necropsies of ferrets injected with IFN-a2b or infected with SARS-CoV/Tor 2 strain, using microarray analysis on the Affymetrix platform. Results: We identified a common IRG signature that was upregulated in both SARS-CoV infected ferrets as well as in ferrets injected with IFN-a2b. We also identified unique patterns of gene expression for leukocyte activation, cell adhesion and complement pathways between IFN-a2b injection and SARS-CoV infection. Conclusions: Our results define the effects of IFN-a2b on the immune system of ferrets highlighting genes regulated by IFN during SARS-CoV infection. We have shown the similarities and differences of top funcional gene groups as well as pathways that play key roles in early immune responses in ferrets in response to IFN-a2b or SARS-CoV. Key words: ferret, gene expression, SARS, interferon. Keywords: time course In experiments with IFN-a2b, for peripheral blood, 15 ferrets were randomly allocated to 3 groups: Day 0, 5 ferrets (no IFN injection), day 1, 6 ferrets (injected), and day 2, 4 ferrets (injected). For lung necropsies of injected ferrets with IFN-a2b, we used 12 ferrets in 3 groups: 4 ferrets, day 0 (no IFN injection), 4 ferrets, day 1 (injected) and 4 ferrets, day 2 (injected). Experimental groups for SARS-CoV infection was as follows: For peripheral blood, 3 and 4 ferrets for day 0 (no infection) and day 2 (infection) respectively. For lung neceropsies, a total of 9 ferrets in 3 groups, each with 3 replicates for day 0 (no infection), day 1 (infection) and day 2 (infection).
Project description:To investigate the role of m6A modification during SFTSV infection, we established a SFTSV-infected cell model, in which each m6A modification change was identified.