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Background: Genetic association studies have demonstrated that the SNP rs12603332 located on chromosome 17q21 is highly associated with the risk of the development of asthma. Methods: To determine whether SNP rs1260332 is functional in regulating levels of ORMDL3 expression, we used a Cytosine Base Editor (CBE) plasmid DNA or a CBE mRNA to edit the rs12603332 C risk allele to the T non‐risk allele in a human lymphocyte cell line (i.e., Jurkat cells) and in primary human CD4 T cells that carry the C risk alleles. Results: Jurkat cells with the rs12603332 C risk allele expressed significantly higher levels of ORMDL3 mRNA, as well as the ORMDL3 regulated gene ATF6α as assessed by qPCR compared to Jurkat clones with the T non‐risk allele. In primary human CD4 T cells, we edited 90 ± 3% of the rs12603332‐C risk allele to the T non‐risk allele and observed a reduction in ORMDL3 and ATF6α expression. Bioinformatic analysis predicted that the non‐risk allele rs12603332‐T could be the central element of the E‐box binding motif (CANNTG) recognized by the E47 transcription factor. An EMSA assay confirmed the bioinformatics prediction demonstrating that a rs12603332‐T containing probe bound to the transcription factor E47 in vitro. Conclusions: SNP rs12603332 is functional in regulating the expression of ORMDL3 as well as ORMDL3 regulated gene ATF6α expression. In addition, we demonstrate the use of CBE technology in functionally interrogating asthma‐associated SNPs using studies of primary human CD4 cells. [ABSTRACT FROM AUTHOR]

Dysregulation of airway smooth muscle cells (ASM) is central to the severity of asthma. Which molecules dominantly control ASM in asthma is unclear. High levels of the cytokine LIGHT (aka TNFSF14) have been linked to asthma severity and lower baseline predicted FEV 1 percentage, implying that signals through its receptors might directly control ASM dysfunction. Our study sought to determine whether signaling via lymphotoxin beta receptor (LTβR) or herpesvirus entry mediator from LIGHT dominantly drives ASM hyperreactivity induced by allergen. Conditional knockout mice deficient for LTβR or herpesvirus entry mediator in smooth muscle cells were used to determine their role in ASM deregulation and airway hyperresponsiveness (AHR) in vivo. Human ASM were used to study signals induced by LTβR. LTβR was strongly expressed in ASM from normal and asthmatic subjects compared to several other receptors implicated in smooth muscle deregulation. Correspondingly, conditional deletion of LTβR only in smooth muscle cells in smMHCCreLTβRfl/fl mice minimized changes in their numbers and mass as well as AHR induced by house dust mite allergen in a model of severe asthma. Intratracheal LIGHT administration independently induced ASM hypertrophy and AHR in vivo dependent on direct LTβR signals to ASM. LIGHT promoted contractility, hypertrophy, and hyperplasia of human ASM in vitro. Distinguishing LTβR from the receptors for IL-13, TNF, and IL-17, which have also been implicated in smooth muscle dysregulation, LIGHT promoted NF-κB–inducing kinase-dependent noncanonical nuclear factor kappa–light-chain enhancer of activated B cells in ASM in vitro, leading to sustained accumulation of F-actin, phosphorylation of myosin light chain kinase, and contractile activity. LTβR signals directly and dominantly drive airway smooth muscle hyperresponsiveness relevant for pathogenesis of airway remodeling in severe asthma. [ABSTRACT FROM AUTHOR]

PGAP3 is a glycosylphosphatidylinositol (GPI) phospholipase gene localized within chromosome 17q12-21, a region highly linked to asthma. Although much is known about the function of other chromosome 17q12-21 genes expressed at increased levels in bronchial epithelium such as ORMDL3 and GSDMB, little is known about the function of increased PGAP3 expression in bronchial epithelium in the context of asthma. The aim of this study was therefore to determine whether increased PGAP3 expression in human bronchial epithelial cells regulated expression of mRNA pathways important to the pathogenesis of asthma by utilizing RNA-sequencing and bioinformatic analysis. We performed RNA-sequencing on normal human bronchial epithelial cells transfected with PGAP3 for 24 and 48 hours. PGAP3 regulated genes were compared to asthma and respiratory virus (influenza A, rhinovirus, respiratory syncytial virus) reference data sets to identify PGAP3 target genes and pathways. Approximately 9% of the upregulated PGAP3-induced genes were found in an asthma reference data set, 41% in a rhinovirus reference data set, 33% in an influenza A reference data set, and 3% in a respiratory syncytial virus reference data set. PGAP3 significantly upregulated the expression of several genes associated with the innate immune response and viral signatures of respiratory viruses associated with asthma exacerbations. Two of the highest expressed genes induced by PGAP3 are RSAD2, OASL, and IFN-λ, which are anti-viral genes associated with asthma. PGAP3 also upregulated the antiviral gene BST2, which like PGAP3 is a GPI-anchored protein. We conclude that PGAP3 expression in human bronchial epithelial cells regulates expression of genes known to be linked to asthma, and also regulates the bronchial epithelial expression of genes pertinent to the pathogenesis of respiratory viral triggered asthma exacerbations., Competing Interests: Statement of Competing Interests Authors did not receive any third-party payments or services that influenced the submitted work.