In juvenile dermatomyositis (JDM), the most common pediatric inflammatory myopathy, weakness is accompanied by a characteristic rash that often becomes chronic and is associated with vascular damage. We hoped to understand the molecular underpinnings of JDM, particularly when untreated, which would facilitate the identification of novel mechanisms and clinical targets that might disrupt disease progression. We studied the RNA-Seq data from untreated JDM peripheral blood mononuclear cells (PBMCs; n = 11), PBMCs from a subset of the same patients when clinically inactive (n = 8/11), and separate samples of untreated JDM skin and muscle (n = 4 each). All JDM samples were compared to non-inflammatory control tissues. The untreated JDM PBMCs showed a strong signature for type1 interferon response, along with IL-1, IL-10, and NF-κB. Surprisingly, PBMCs from clinically inactive JDM individuals had persistent immune activation that was enriched for IL-1 signaling. JDM skin and muscle both showed evidence for type 1 interferon activation and genes related to antigen presentation and decreased expression of cellular respiration genes. Additionally, we found that PBMC gene expression correlates with disease activity scores (DAS; skin, muscle, and total domains) and with nailfold capillary end row loop number (an indicator of microvascular damage). This included otoferlin, which was significantly increased in untreated JDM PBMCs and correlated with all 3 DAS domains. Overall, these data demonstrate that PBMC transcriptomes are informative of molecular disruptions in JDM and provide transcriptional evidence of chronic inflammation despite clinical quiescence.

STING gain-of-function causes autoimmunity and immunodeficiency in mice and STING-associated vasculopathy with onset in infancy (SAVI) in humans. Here, we report that STING gain-of-function in mice prevents development of lymph nodes and Peyer's patches. We show that the absence of secondary lymphoid organs is associated with diminished numbers of innate lymphoid cells (ILCs), including lymphoid tissue inducer (LTi) cells. Although wild-type (WT) a4b7 + progenitors differentiate efficiently into LTi cells, STING gain-of-function progenitors do not. Furthermore, STING gain-of-function impairs development of all types of ILCs. Patients with STING gain-of-function mutations have fewer ILCs, although they still have lymph nodes. In mice, expression of the STING mutant in RORgT-positive lineages prevents development of lymph nodes and reduces numbers of LTi cells. RORgT lineage-specific expression of STING gain-of-function also causes lung disease. Since RORgT is expressed exclusively in LTi cells during fetal development, our findings suggest that STING gain-of-function prevents lymph node organogenesis by reducing LTi cell numbers in mice.

No abstract

No abstract

15CRISPR/Cas9 is emerging as one of the most-used methods of genome modification in 16 organisms ranging from bacteria to human cells. However, the efficiency of editing 17 varies tremendously site-to-site. A recent report identified a novel motif, called the 18 3'GG motif, which substantially increases the efficiency of editing at all sites tested in C. 19 elegans. Furthermore, they highlighted that previously published gRNAs with high 20 editing efficiency also had this motif. I designed a python command-line tool, ngg2, to 21 identify 3'GG gRNA sites from indexed FASTA files. As a proof-of-concept, I screened 22 for these motifs in six model genomes: Saccharomyces cerevisiae, Caenorhabditis elegans, 23 Drosophila melanogaster, Danio rerio, Mus musculus, and Homo sapiens. I also scanned the 24 genomes of pig (Sus scrofa) and African elephant (Loxodonta africana) to demonstrate the 25 utility in non-model organisms. I identified more than 60 million single match 3'GG 26 motifs in these genomes. Greater than 61% of all protein coding genes in the reference 27 genomes had at least one unique 3'GG gRNA site overlapping an exon. In particular, 28 more than 96% of mouse and 93% of human protein coding genes have at least one 29 unique, overlapping 3'GG gRNA. These identified sites can be used as a starting point 30