@article {152, title = {Genetic and non-genetic factors affecting the expression of COVID-19-relevant genes in the large airway epithelium.}, journal = {Genome Med}, volume = {13}, year = {2021}, month = {2021 04 21}, pages = {66}, abstract = {

BACKGROUND: The large airway epithelial barrier provides one of the first lines of defense against respiratory viruses, including SARS-CoV-2 that causes COVID-19. Substantial inter-individual variability in individual disease courses is hypothesized to be partially mediated by the differential regulation of the genes that interact with the SARS-CoV-2 virus or are involved in the subsequent host response. Here, we comprehensively investigated non-genetic and genetic factors influencing COVID-19-relevant bronchial epithelial gene expression.

METHODS: We analyzed RNA-sequencing data from bronchial epithelial brushings obtained from uninfected individuals. We related ACE2 gene expression to host and environmental factors in the SPIROMICS cohort of smokers with and without chronic obstructive pulmonary disease (COPD) and replicated these associations in two asthma cohorts, SARP and MAST. To identify airway biology beyond ACE2 binding that may contribute to increased susceptibility, we used gene set enrichment analyses to determine if gene expression changes indicative of a suppressed airway immune response observed early in SARS-CoV-2 infection are also observed in association with host factors. To identify host genetic variants affecting COVID-19 susceptibility in SPIROMICS, we performed expression quantitative trait (eQTL) mapping and investigated the phenotypic associations of the eQTL variants.

RESULTS: We found that ACE2 expression was higher in relation to active smoking, obesity, and hypertension that are known risk factors of COVID-19 severity, while an association with interferon-related inflammation was driven by the truncated, non-binding ACE2 isoform. We discovered that expression patterns of a suppressed airway immune response to early SARS-CoV-2 infection, compared to other viruses, are similar to patterns associated with obesity, hypertension, and cardiovascular disease, which may thus contribute to a COVID-19-susceptible airway environment. eQTL mapping identified regulatory variants for genes implicated in COVID-19, some of which had pheWAS evidence for their potential role in respiratory infections.

CONCLUSIONS: These data provide evidence that clinically relevant variation in the expression of COVID-19-related genes is associated with host factors, environmental exposures, and likely host genetic variation.

}, keywords = {Adult, Aged, Aged, 80 and over, Angiotensin-Converting Enzyme 2, Asthma, Bronchi, Cardiovascular Diseases, COVID-19, Gene Expression, Genetic Variation, Humans, Middle Aged, Obesity, Pulmonary Disease, Chronic Obstructive, Quantitative Trait Loci, Respiratory Mucosa, Risk Factors, SARS-CoV-2, Smoking}, issn = {1756-994X}, doi = {10.1186/s13073-021-00866-2}, author = {Kasela, Silva and Ortega, Victor E and Martorella, Molly and Garudadri, Suresh and Nguyen, Jenna and Ampleford, Elizabeth and Pasanen, Anu and Nerella, Srilaxmi and Buschur, Kristina L and Barjaktarevic, Igor Z and Barr, R Graham and Bleecker, Eugene R and Bowler, Russell P and Comellas, Alejandro P and Cooper, Christopher B and Couper, David J and Criner, Gerard J and Curtis, Jeffrey L and Han, MeiLan K and Hansel, Nadia N and Hoffman, Eric A and Kaner, Robert J and Krishnan, Jerry A and Martinez, Fernando J and McDonald, Merry-Lynn N and Meyers, Deborah A and Paine, Robert and Peters, Stephen P and Castro, Mario and Denlinger, Loren C and Erzurum, Serpil C and Fahy, John V and Israel, Elliot and Jarjour, Nizar N and Levy, Bruce D and Li, Xingnan and Moore, Wendy C and Wenzel, Sally E and Zein, Joe and Langelier, Charles and Woodruff, Prescott G and Lappalainen, Tuuli and Christenson, Stephanie A} } @article {119, title = {Identification of Required Host Factors for SARS-CoV-2 Infection in Human Cells.}, journal = {Cell}, volume = {184}, year = {2021}, month = {2021 01 07}, pages = {92-105.e16}, abstract = {

To better understand host-virus genetic dependencies and find potential therapeutic targets for COVID-19, we performed a genome-scale CRISPR loss-of-function screen to identify host factors required for SARS-CoV-2 viral infection of human alveolar epithelial cells. Top-ranked genes cluster into distinct pathways, including the vacuolar ATPase proton pump, Retromer, and Commander complexes. We validate these gene targets using several orthogonal methods such as CRISPR knockout, RNA interference knockdown, and small-molecule inhibitors. Using single-cell RNA-sequencing, we identify shared transcriptional changes in cholesterol biosynthesis upon loss of top-ranked genes. In addition, given the key role of the ACE2 receptor in the early stages of viral entry, we show that loss of RAB7A reduces viral entry by sequestering the ACE2 receptor inside cells. Overall, this work provides a genome-scale, quantitative resource of the impact of the loss of each host gene on fitness/response to viral infection.

}, keywords = {A549 Cells, Alveolar Epithelial Cells, Angiotensin-Converting Enzyme 2, Biosynthetic Pathways, Cholesterol, Clustered Regularly Interspaced Short Palindromic Repeats, COVID-19, Endosomes, Gene Expression Profiling, Gene Knockdown Techniques, Gene Knockout Techniques, Genome-Wide Association Study, Host-Pathogen Interactions, Humans, rab GTP-Binding Proteins, rab7 GTP-Binding Proteins, RNA Interference, SARS-CoV-2, Single-Cell Analysis, Viral Load}, issn = {1097-4172}, doi = {10.1016/j.cell.2020.10.030}, author = {Daniloski, Zharko and Jordan, Tristan X and Wessels, Hans-Hermann and Hoagland, Daisy A and Kasela, Silva and Legut, Mateusz and Maniatis, Silas and Mimitou, Eleni P and Lu, Lu and Geller, Evan and Danziger, Oded and Rosenberg, Brad R and Phatnani, Hemali and Smibert, Peter and Lappalainen, Tuuli and tenOever, Benjamin R and Sanjana, Neville E} } @article {123, title = {Type 2 and interferon inflammation regulate SARS-CoV-2 entry factor expression in the airway epithelium.}, journal = {Nat Commun}, volume = {11}, year = {2020}, month = {2020 10 12}, pages = {5139}, abstract = {

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.

}, keywords = {Angiotensin-Converting Enzyme 2, Betacoronavirus, Child, Coronavirus Infections, COVID-19, Epithelial Cells, Gene Expression Profiling, Gene Expression Regulation, Genetic Variation, Host-Pathogen Interactions, Humans, Inflammation, Interferons, Interleukin-13, Middle Aged, Nasal Mucosa, Pandemics, Peptidyl-Dipeptidase A, Pneumonia, Viral, SARS-CoV-2, Serine Endopeptidases, Virus Internalization}, issn = {2041-1723}, doi = {10.1038/s41467-020-18781-2}, author = {Sajuthi, Satria P and DeFord, Peter and Li, Yingchun and Jackson, Nathan D and Montgomery, Michael T and Everman, Jamie L and Rios, Cydney L and Pruesse, Elmar and Nolin, James D and Plender, Elizabeth G and Wechsler, Michael E and Mak, Angel C Y and Eng, Celeste and Salazar, Sandra and Medina, Vivian and Wohlford, Eric M and Huntsman, Scott and Nickerson, Deborah A and Germer, Soren and Zody, Michael C and Abecasis, Gon{\c c}alo and Kang, Hyun Min and Rice, Kenneth M and Kumar, Rajesh and Oh, Sam and Rodriguez-Santana, Jose and Burchard, Esteban G and Seibold, Max A} }