Project description:Several humanized ACE2 (hACE2) mouse models have been developed for COVID-19 studies. Insertion of hACE2 at mouse Ace2 locus enables the utilization of endogenous promoter to drive its expression, better reflecting ACE2 abundance in various cell types and tissues. However, the relatively low expression of hACE2 in these mice may limit their fidelity in mimicking COVID-19 manifestations in humans and hinder their application in viral studies. In this study, we generated four hACE2 mouse models using different strategies for hACE2 expression. We found that the position of the β-globin intron within hACE2 cassette could have contrasting effects on hACE2 expression, with its placement downstream of hACE2 significantly increasing its transcription. Western blot analysis demonstrated that optimizing hACE2 codon usage further enhanced translation efficiency from all tested tissue. Consistent with elevated hACE2 expression, opt-hACE2 mice displayed more active immune response and severe COVID-19 phenotypes following SARS-CoV-2 challenging compared to other hACE2 mouse models. Thus, our study has elucidated the dual role of β-globin element in transgene expression, and highlighted that mice with optimized hACE2 codon preference could serve as a better model for SARS-CoV-2 studies.
Project description:Humanized mouse models and mouse-adapted SARS-CoV-2 virus are increasingly used to study COVID-19 pathogenesis, and it is therefore important to learn where the SARS-CoV-2 receptor ACE2 is expressed. Here we mapped ACE2 expression during mouse postnatal development and in adulthood. Pericytes in the central nervous system, heart and pancreas express ACE2 strongly, as do perineurial and adrenal fibroblasts, whereas endothelial cells do not at any location analyzed. In a number of other organs pericytes do not express ACE2, including in the lung where ACE2 instead is expressed in bronchial epithelium and alveolar type-II cells. The onset of ACE2 expression is organ-specific: in bronchial epithelium already at birth, in brain pericytes before and in heart pericytes after postnatal day 10.5. Establishing the vascular localization of ACE2 expression is central to correctly interpret data from modelling COVID-19 in the mouse and may shed light on the cause of vascular COVID-19 complications.
Project description:Flow cytometry sorted B-cells reactive to ACE2 peptides isolated from peripheral blood of COVID-19 patients compared with non-reactive B-cells using pooled hashtag barcoding and 10x genomics 5'DGE kit and VDJ recombination of B-cells
Project description:SARS-CoV-2, the virus responsible for COVID-19, employs two key host proteins to gain entry and replicate within cells, angiotensin-converting enzyme 2 (ACE2) and the cell surface transmembrane protease serine 2 (TMPRSS2). TMPRSS2 was first characterized as an androgen-regulated gene in the prostate. Supporting a role for sex hormones, males relative to females are disproportionately affected by COVID-19 in terms of mortality and morbidity. Several studies, including one employing a large epidemiological cohort, suggested that blocking androgen signaling is protective against COVID-19. Here, we demonstrate that androgens regulate the expression of ACE2, TMPRSS2, and androgen receptor (AR) in subsets of lung epithelial cells. AR levels are markedly elevated in males relative to females greater than 70 years of age. In males greater than 70 years old, smoking was associated with elevated levels of AR and ACE2 in lung epithelial cells. Transcriptional repression of the AR enhancesome with AR or bromodomain and extraterminal domain (BET) antagonists inhibited SARS-CoV-2 infection in vitro. Taken together, these studies support further investigation of transcriptional inhibition of critical host factors in the treatment or prevention of COVID-19. These mouse data are part of a larger investigation (data not provided here) targeting the transcriptional regulation of SARS-CoV-2 entry factors ACE2 and TMPRSS2.
Project description:The homologous Ace2 and Swi5 transcription factors of Saccharomyces cerevisiae have identical DNA-binding domains, and both are cell cycle regulated. There are common target genes, as well as genes activated only by Ace2 and other genes activated only by Swi5. Keywords: genetic modification RNA was isolated from four strains: wild type, ace2 gene deletion, swi5 gene deletion, and the ace2 swi5 double gene deletion. RNAs from the three mutant strains were compared to wild type RNA in a microarray hybridization experiment.
Project description:Genetic differences are a primary reason for differences in the susceptibility and severity of COVID-19. As induced pluripotent stem (iPS) cells maintain the genetic information of the donor, they can be used to model individual differences in SARS-CoV-2 infection in vitro. We found that human iPS cells expressing the SARS-CoV-2 receptor angiotensin-converting enzyme 2 (ACE2) (ACE2-iPS cells) can be infected w SARS-CoV-2. In infected ACE2-iPS cells, the expression of SARS-CoV-2 nucleocapsid protein, budding of viral particles, and production of progeny virus, double membrane spherules, and double-membrane vesicles were confirmed. We performed SARS-CoV-2 infection experiments on ACE2-iPS/ embryonic stem (ES) cells from eight individuals. Male iPS/ES cells were more capable of producing the virus compared with female iPS/ES cells. These findings suggest that ACE2-iPS cells can not only reproduce individual differences in SARS-CoV-2 infection in vitro but also are a useful resource to clarify the causes of individual differences in COVID-19 due to genetic differences.
Project description:BMPR2 mutation causes pulmonary arterial hypertension (PAH); ACE2 treatment can resolve established BMPR2-mediated PAH. The purpose of this study was to uncover the molecular mechanism behind this. Four groups: +/- ACE2 and +/- BMPR2 transgene, two arrays each, each array a pool of three animals.
Project description:SARS-CoV-2 infects host cells via an ACE2/TMPRSS2 entry mechanism. Monocytes and macrophages, which play a key role during severe COVID-19 express only low or no ACE2, suggesting alternative entry mechanisms in these cells. In silico analyses predicted GRP78, which is constitutively expressed on monocytes and macrophages, to be a potential candidate receptor for SARS-CoV-2 virus entry. To confirm the hypothesis, we conducted high-throughput RNA sequence to characterize the role of GRP78 in monocytes function in COVID-19 patients
Project description:Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), the causative agent of COVID-19, continues to spread around the world with serious cases and deaths. It has also been suggested that different genetic variants in the human genome affect both the susceptibility to infection and severity of disease in COVID-19 patients. Angiotensin-converting enzyme 2 (ACE2) has been identified as a cell surface receptor for SARS-CoV and SARS-CoV-2 entry into cells. The construction of an experimental model system using human iPS cells would enable further studies of the association between viral characteristics and genetic variants. Airway and alveolar epithelial cells are cell types of the lung that express high levels of ACE2 and are suitable for in vitro infection experiments. Here, we show that human iPS cell-derived airway and alveolar epithelial cells are highly susceptible to viral infection of SARS-CoV-2. Using gene knockout with CRISPR-Cas9 in human iPS cells we demonstrate that ACE2 plays an essential role in the airway and alveolar epithelial cell entry of SARS-CoV-2 in vitro. Replication of SARS-CoV-2 was strongly suppressed in ACE2 knockout (KO) lung cells. Our model system based on human iPS cell-derived lung cells may be applied to understand the molecular biology regulating viral respiratory infection leading to potential therapeutic developments for COVID-19 and the prevention of future pandemics.
Project description:SARS-CoV-2 infection of human airway epithelium activates genetic programs leading to progressive hyperinflammation in COVID-19 patients. Here, we report on transcriptomes activated in primary airway cells by interferons and their suppression by Janus kinase (JAK) inhibitors. Deciphering the regulation of the angiotensin-converting enzyme 2 (ACE2), the receptor for SARS-CoV-2, is paramount for understanding the cell tropism of SARS-CoV-2 infection. ChIP-seq for activating histone marks and Pol II loading identified candidate enhancer elements controlling the ACE2 locus, including the intronic dACE2 promoter. Employing RNA-seq, we demonstrate that interferons activate expression of dACE2 and, to a lesser extent, the genuine ACE2 gene. Interferon-induced gene expression was mitigated by the JAK inhibitors baricitinib and ruxolitinib, used therapeutically in COVID-19 patients. Through integrating RNA-seq and ChIP-seq data we provide an in-depth understanding of genetic programs activated by interferons, and our study highlights JAK inhibitors as suitable tools to suppress these in bronchial cells.