Highlights d Numerous SARS-CoV-2 proteins synergize to suppress immune sensing and signaling d Nsp14 targets IFNAR1 for lysosomal degradation d ORF3a and ORF7a block autophagy by different mechanisms d Synergistic treatment with IFN-g and -l1 is highly effective against SARS-CoV-2

Duchenne muscular dystrophy (DMD) is a severe, progressive muscle disease caused by mutations in the dystrophin gene. The majority of DMD mutations are deletions that prematurely terminate the dystrophin protein. Deletions of exon 50 of the dystrophin gene are among the most common single exon deletions causing DMD. Such mutations can be corrected by skipping exon 51, thereby restoring the dystrophin reading frame. Using clustered regularly interspaced short palindromic repeats/CRISPR-associated 9 (CRISPR/Cas9), we generated a DMD mouse model by deleting exon 50. These ΔEx50 mice displayed severe muscle dysfunction, which was corrected by systemic delivery of adeno-associated virus encoding CRISPR/Cas9 genome editing components. We optimized the method for dystrophin reading frame correction using a single guide RNA that created reframing mutations and allowed skipping of exon 51. In conjunction with muscle-specific expression of Cas9, this approach restored up to 90% of dystrophin protein expression throughout skeletal muscles and the heart of ΔEx50 mice. This method of permanently bypassing DMD mutations using a single cut in genomic DNA represents a step toward clinical correction of DMD mutations and potentially those of other neuromuscular disorders.

Longitudinal analyses of the innate immune system including earliest time points are essential to understand the immunopathogenesis and clinical course of COVID-19. Here, we performed a detailed characterization of natural killer cells in 205 patients (403 samples, day 2-41 after symptom onset) from four independent cohorts using single-cell transcriptomics and proteomics together with functional studies. We found elevated IFN-α plasma levels in early severe COVD-19 alongside increased NK cell expression of ISGs and genes involved in IFN-α signaling, while upregulation of TNF-induced genes was observed in moderate disease. NK cells exert anti-SARS-CoV-2 activity but are functionally impaired in severe COVID-19. Further, NK cell dysfunction may be relevant for development of fibrotic lung disease in severe COVID-19, as NK cells exhibited impaired anti-fibrotic activity. Our study indicates preferential IFN-α and TNF responses in severe and moderate COVID-19, respectively, and associates prolonged IFN-α-induced NK cell response with poorer disease outcome.

Ploegh et al. raised an alpaca single-domain antibody (VHH) against the inflammasome adaptor ASC. VHHASC blocks inflammasome activation in vitro and in living cells, and demonstrates a role of the ASC CARD domain in cross-linking ASC Pyrin domain filaments.