Coronavirus disease 2019 (COVID-19) is caused by SARS-CoV-2, an emerging virus that utilizes host proteins ACE2 and TMPRSS2 as entry factors. Understanding the factors affecting the pattern and levels of expression of these genes is important for deeper understanding of SARS-CoV-2 tropism and pathogenesis. Here we explore the role of genetics and co-expression networks in regulating these genes in the airway, through the analysis of nasal airway transcriptome data from 695 children. We identify expression quantitative trait loci for both ACE2 and TMPRSS2, that vary in frequency across world populations. We find TMPRSS2 is part of a mucus secretory network, highly upregulated by type 2 (T2) inflammation through the action of interleukin-13, and that the interferon response to respiratory viruses highly upregulates ACE2 expression. IL-13 and virus infection mediated effects on ACE2 expression were also observed at the protein level in the airway epithelium. Finally, we define airway responses to common coronavirus infections in children, finding that these infections generate host responses similar to other viral species, including upregulation of IL6 and ACE2. Our results reveal possible mechanisms influencing SARS-CoV-2 infectivity and COVID-19 clinical outcomes.

32Coronavirus disease 2019 outcomes vary from asymptomatic infection to 33 death. This disparity may reflect different airway levels of the SARS-CoV-2 receptor, 34 ACE2, and the spike protein activator, TMPRSS2. Here we explore the role of genetics 35 and co-expression networks in regulating these genes in the airway, through the 36 analysis of nasal airway transcriptome data from 695 children. We identify expression 37 quantitative trait loci (eQTL) for both ACE2 and TMPRSS2, that vary in frequency 38 across world populations. Importantly, we find TMPRSS2 is part of a mucus secretory 39 network, highly upregulated by T2 inflammation through the action of interleukin-13, and 40 that interferon response to respiratory viruses highly upregulates ACE2 expression. 41Finally, we define airway responses to coronavirus infections in children, finding that 42 these infections upregulate IL6 while also stimulating a more pronounced cytotoxic 43 immune response relative to other respiratory viruses. Our results reveal mechanisms 44 likely influencing SARS-CoV-2 infectivity and COVID-19 clinical outcomes. 45 46 47 48 IL-13), which is common in both children and adults and has been associated with the 87 development of both asthma and COPD in a subgroup of patients [11][12][13] . T2 cytokines are 88 known to greatly modify gene expression in the airway epithelium, both through 89 transcriptional changes within cells and epithelial remodeling in the form of mucus 90 metaplasia 11, 14, 15 . Microbial infection is another strong regulator of airway epithelial 91 expression. In particular, respiratory viruses can modulate the expression of thousands 92 of genes within epithelial cells, while also recruiting and activating an assortment of 93 immune cells [16][17][18] . Even asymptomatic nasal carriage of respiratory viruses, which is 94 especially common in childhood, has been shown to be associated with both genome-95 wide transcriptional re-programming and infiltration of macrophages and neutrophils in 96 the airway epithelium 19 , demonstrating how viral infection can drive pathology even 97 without overt signs of illness. 98 99 . CC-BY-NC-ND 4.0 International license was not certified by peer review) is the author/funder. It is made available under a Genetic variation is another factor that may regulate gene expression in the airway 100 epithelium. Indeed, expression quantitative trait loci (eQTL) analyses carried out in 101 many tissues have suggested that as many as 70% of genes expressed by a tissue or 102organ are under genetic control 20 . Severity of human rhinovirus (HRV) respiratory illness 103 has specifically been associated with genetic variation in the epithelial genes CDHR3 21 104 and the ORMDL3 22 and, given differences in genetic variation across world populations, 105 it is possible that functional genetic variants in SARS-CoV-2-related genes could partly 106 explain population differences in COVID-19 clinical outcomes. 107 108 Finally, there are important questions regarding the host response to SARS-CoV-2...

The lack of minority data, despite a collaboration of eight universities and 13 individual laboratories, highlights the urgent need for a dedicated national effort to prioritize diversity in research. Our study expands the understanding of pharmacogenetic analyses in racially/ethnically diverse populations and advances the foundation for precision medicine in at-risk and understudied minority populations.

The major cause of mortality in breast cancer is the progression of metastatic disease. Although loss of oestrogen receptors (ER) and progesterone receptors is associated with more aggressive disease, 30% of patients with receptor-positive, node-negative tumours develop metastases (Price et al, 1997). A component of the metastatic process is invasion, which is accomplished when the cells can transit the extracellular matrix (ECM) layer. More accurate prognoses might be possible if factors could be identified that either promote invasion or are markers for it, independent of steroid receptor status. Specific treatments to prevent invasion might also be developed.Thrombin is a growth-regulatory protein at nanomolar concentrations. Thrombin is also a serine proteinase that is generally associated with coagulation. Its proenzyme, prothrombin, occurs in the plasma at concentrations up to 3 µM (Shapiro and McCord, 1978). Thrombin and its associated receptor, TR-1, are involved in the activation of platelets (McNicol and Gerrard, 1993;Vittet and Chevillard, 1993), growth stimulation of immature rat uterine stromal cells (Arena et al, 1996), alteration of permeability in vascular endothelial cells (DeMichele and Minnear, 1992;Garcia et al, 1995), DNA synthesis in astrocytoma cells (Aragay et al, 1995) and endothelial cell growth in angiogenesis (Fidler and Ellis, 1994). Thrombin also has been implicated in tumour progression (Wojtukiewicz et al, 1995).The initial step in characterization of thrombinÕs role in breast tumour cell invasion is a description of the presence of TR-1 on invasive breast tumour cell lines and of thrombinÕs influence on in vitro invasion by those cell lines. We report the presence of TR-1 and activity of thrombin in stimulating invasion by the MDA-MB231 breast cancer cell line and its absence in other, less aggressive, breast tumour cell lines. MATERIALS AND METHODS Cell cultureCells were cultured in DulbeccoÕs modified Eagle medium (DMEM) without phenol red, with streptomycin, penicillin, nonessential amino acids, glutamine and 5% serum (Hyclonedefined calf serum for MDA-MB231 and MDA-MB436; Gibco fetal calf serum for MCF-7 cells).Conditioned medium was prepared by incubating confluent 3T3 cultures with bovine serum albumin (BSA) medium (DMEM without phenol red, containing 0.1% BSA and antibiotics) for 24 h. Conditioned medium was stored frozen and was centrifuged immediately before use to remove cells and debris. Invasion assaysInvasion chambers with 8-µm pores were purchased from BectonÐDickinson. Chambers were used without modification for chemotaxis assays. Matrigel-coated chambers were used for invasion assays. Matrigel, purchased from BectonÐDickinson, was diluted in ice-cold DMEM without additions. One hundred microlitres (38 µg) was pipetted into each chamber in a 24-well plate. The plate was incubated at 37°C for 1 h, then medium was removed by aspiration and replaced with 400 µl of DMEM. Chambers were either used immediately or after overnight storage at 4°C.Assays were performed in 24...