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Biology subjects

Doueck, D. C.

Publications and source records attributed to Doueck, D. C..

4 recordsLinked to original sources

Maximal Efficacy of Alternative Splicing is Ensured by Balanced Efficiency of U1 and U2AF

Alternative splicing (AS) significantly increases the diversity of gene function by enabling a single gene to produce multiple protein isoforms. U1 and U2AF are proteins responsible for the recognition and splicing of an introns donor and acceptor sites, respectively. Here, we used RNA- seq to explore these fundamental splicing events to separately calculate the splicing efficiency of U1 and U2AF. The expression levels of splice sites were directly calculated by the number of uniquely mapped reads spanning the splice junction. We found that the scaled expression levels of donor and acceptor sites both follow a type III extreme value Weibull distribution with the same shape parameter of 0.14. These observations significantly extend our previous findings by revealing that AS follows a Weibull distribution at the levels of both the fundamental splicing event and the mature transcript isoform. A simple transform of the shape parameter a, 1/(1+a), ranges between 0 and 1, and positively correlates with the dominance of the major splicing product and therefore represents an index of the splicing machinery efficiency. Importantly, the equal splicing efficiency of U1 and U2AF ensure that their combined efficacy reaches a maximum.

bioinformatics↗

Investigation of the Impact of Clonal Hematopoiesis on Severity and Pathophysiology of COVID-19 in Rhesus Macaques

Clinical manifestations of COVID-19 vary widely, ranging from asymptomatic to severe respiratory failure with profound inflammation. Although risk factors for severe illness have been identified, definitive determinants remain elusive. Clonal hematopoiesis (CH), the expansion of hematopoietic stem and progenitor cells bearing acquired somatic mutations, is associated with advanced age and hyperinflammation. Given the similar age range and hyperinflammatory phenotype between frequent CH and severe COVID-19, CH could impact the risk of severe COVID-19. Human cohort studies have attempted to prove this relationship, but conclusions are conflicting. Rhesus macaques (RMs) are being utilized to test vaccines and therapeutics for COVID-19. However, RMs, even other species, have not yet been reported to develop late inflammatory COVID-19 disease. Here, RMs with either spontaneous DNMT3A or engineered TET2 CH along with similarly transplanted and conditioned controls were infected with SARS-CoV-2 and monitored until 12 days post-inoculation (dpi). Although no significant differences in clinical symptoms and blood counts were noted, an aged animal with natural DNMT3A CH died on 10 dpi. CH macaques showed evidence of sustained local inflammatory responses compared to controls. Interestingly, viral loads in respiratory tracts were higher at every timepoint in the CH group. Lung sections from euthanasia showed evidence of mild inflammation in all animals, while viral antigen was more frequently detected in the lung tissues of CH macaques even at the time of autopsy. Despite the lack of striking inflammation and serious illness, our findings suggest potential pathophysiological differences in RMs with or without CH upon SARS-CoV-2 infection. HighlightsO_LINo evidence of association between CH and COVID-19 clinical severity in macaques. C_LIO_LIThe presence of CH is associated with prolonged local inflammatory responses in COVID-19. C_LIO_LISARS-CoV-2 persists longer in respiratory tracts of macaques with CH following infection. C_LI

genetics↗

Blood Transcriptional Correlates of BCG-Induced Protection Against Tuberculosis in Rhesus Macaques

Blood-based correlates of vaccine-induced protection against tuberculosis (TB) are urgently needed. We analyzed the blood transcriptome of rhesus macaques immunized with varying doses of intravenous (IV) BCG followed by Mycobacterium tuberculosis (Mtb) challenge. We used high-dose IV BCG recipients for "discovery" and validated our findings in low-dose recipients and in an independent cohort of macaques receiving BCG via different routes. We identified seven vaccine-induced gene modules, including an innate module (module 1) enriched for type 1 interferon and RIG-I-like receptor signaling pathways. Module 1 on day 2 post-vaccination was highly correlated with lung antigen-responsive CD4 T cells at week 8 and with Mtb and granuloma burden following challenge. Parsimonious signatures within module 1 at day 2 post-vaccination predicted protection following challenge with AUROCs [≥] 0.91. Together these results indicate that the early innate transcriptional response to IV BCG in peripheral blood may provide a robust correlate of protection against TB.

immunology↗

Antibodies with potent and broad neutralizing activity against antigenically diverse and highly transmissible SARS-CoV-2 variants

The emergence of highly transmissible SARS-CoV-2 variants of concern (VOC) that are resistant to therapeutic antibodies highlights the need for continuing discovery of broadly reactive antibodies. We identify four receptor-binding domain targeting antibodies from three early-outbreak convalescent donors with potent neutralizing activity against 12 variants including the B.1.1.7 and B.1.351 VOCs. Two of them are ultrapotent, with sub-nanomolar neutralization titers (IC50 <0.0006 to 0.0102 g/mL; IC80 < 0.0006 to 0.0251 g/mL). We define the structural and functional determinants of binding for all four VOC-targeting antibodies, and show that combinations of two antibodies decrease the in vitro generation of escape mutants, suggesting potential means to mitigate resistance development. These results define the basis of therapeutic cocktails against VOCs and suggest that targeted boosting of existing immunity may increase vaccine breadth against VOCs. One Sentence SummaryUltrapotent antibodies from convalescent donors neutralize and mitigate resistance of SARS-CoV-2 variants of concern.

immunology↗