Daily Respiratory Research Analysis

In patients with cystic fibrosis (CF), repeated cycles of infection and inflammation eventually lead to fatal lung damage. Although diminished mucus clearance can be restored by highly effective CFTR modulator therapy, inflammation and infection often persist. To elucidate the role of the innate immune system in CF etiology, we investigated a CF pig model and compared these results with those for preschool children with CF. In newborn CF pigs, we observed changes in lung immune cell composition before the onset of infection that were dominated by increased monocyte infiltration, whereas neutrophil numbers remained constant. Flow cytometric and transcriptomic profiling revealed that the infiltrating myeloid cells displayed a more immature status. Cells with comparably immature transcriptomic profiles were enriched in the blood of CF pigs at birth as well as in preschool children with CF. This pattern coincided with decreased CD16 expression in the myeloid cells of both pigs and humans, which translated into lower phagocytic activity and reduced production of reactive oxygen species in both species. These results were indicative of a congenital, translationally conserved, and functionally relevant aberration of the immune system in CF. In newborn wild-type pigs,

Coronaviruses express their structural and accessory genes via a set of subgenomic RNAs, whose synthesis is directed by transcription regulatory sequences (TRSs) in the 5' genomic leader and upstream of each body open reading frame. In SARS-CoV-2, the TRS has the consensus AAACGAAC; upon searching for emergence of this motif in the global SARS-CoV-2 sequences, we find that it evolves frequently, especially in the 3' end of the genome. We show well-supported examples upstream of the Spike gene-within the nsp16 coding region of ORF1b-which is expressed during human infection, and upstream of the canonical Envelope gene TRS, both of which have evolved convergently in multiple lineages. The most frequent neo-TRS is within the coding region of the Nucleocapsid gene, and is present in virtually all viruses from the B.1.1 lineage, including the variants of concern Alpha, Gamma, Omicron and descendants thereof. Here, we demonstrate that this TRS leads to the expression of a novel subgenomic mRNA encoding a truncated C-terminal portion of Nucleocapsid, which is an antagonist of type I interferon production and contributes to viral fitness during infection. We observe distinct phenotypes when the Nucleocapsid coding sequence is mutated compared to when the TRS alone is ablated. Our findings demonstrate that SARS-CoV-2 is undergoing evolutionary changes at the functional RNA level in addition to the amino acid level.

IMPORTANCE: Chronic obstructive pulmonary disease (COPD) is often undiagnosed. Although genetic risk plays a significant role in COPD susceptibility, its utility in guiding spirometry testing and identifying undiagnosed cases is unclear. OBJECTIVE: To determine whether a COPD polygenic risk score (PRS) enhances the identification of undiagnosed COPD beyond a case-finding questionnaire (eg, the Lung Function Questionnaire) using conventional risk factors and respiratory symptoms. DESIGN, SETTING, AND PARTICIPANTS: This cross-sectional analysis of participants 35 years or older who reported no history of physician-diagnosed COPD was conducted using data from 2 observational studies: the community-based Framingham Heart Study (FHS) and the COPD-enriched Genetic Epidemiology of COPD (COPDGene) study. EXPOSURES: Modified Lung Function Questionnaire (mLFQ) scores and COPD PRS. MAIN OUTCOMES AND MEASURES: The primary outcome was spirometry-defined moderate to severe COPD (forced expiratory volume in the first second of expiration/forced vital capacity [FEV1/FVC] <0.7 and FEV1 [percent predicted] <80%). The performance of logistic models was assessed using the PRS, mLFQ score, and PRS plus mLFQ score for predicting spirometry-defined COPD. RESULTS: Among 3385 FHS participants (median age, 52.0 years; 45.9% male) and 4095 COPDGene participants (median age, 56.8 years; 55.5% male) who reported no history of COPD, 160 (4.7%) FHS and 775 (18.9%) COPDGene participants had spirometry-defined COPD. Adding the PRS to the mLFQ score significantly improved the area under the curve from 0.78 to 0.84 (P < .001) in FHS, 0.69 to 0.72 (P = .04) in COPDGene non-Hispanic African American, and 0.75 to 0.78 (P < .001) in COPDGene non-Hispanic White participants. At a risk threshold for spirometry referral of 10%, the addition of the PRS to the mLFQ score correctly reclassified 13.8% (95% CI, 6.6%-21.0%) of COPD cases in FHS, but not in COPDGene. CONCLUSIONS AND RELEVANCE: A COPD PRS enhances the identification of undiagnosed COPD beyond a conventional case-finding approach in the general population. Further research is needed to assess its impact on COPD diagnosis and outcomes.