SARS-CoV-2-Mediated Lung Edema and Replication Are Diminished by Cystic Fibrosis Transmembrane Conductance Regulator Modulators.

Coronaviruses (CoVs) of genera α, ß, γ, and δ encode proteins that have a PDZ-binding motif (PBM) consisting of the last four residues of the envelope (E) protein (PBM core). PBMs may bind over 400 cellular proteins containing PDZ domains (an acronym formed by the combination of the first letter of the names of the three first proteins where this domain was identified), making them relevant for the control of cell function. Three highly pathogenic human CoVs have been identified to date: severe acute respiratory syndrome coronavirus (SARS-CoV) and Middle East respiratory syndrome coronavirus (MERS-CoV), and SARS-CoV-2. The PBMs of the three CoVs were virulence factors. SARS-CoV mutants in which the E protein PBM core was replaced by the E protein PBM core from virulent or attenuated CoVs were constructed. These mutants showed a gradient of virulence, depending on whether the alternative PBM core introduced was derived from a virulent or an attenuated CoV. Gene expression patterns in the lungs of mice infected with SARS-CoVs encoding each of the different PBMs were analyzed by RNA sequencing of infected lung tissues. E protein PBM of SARS-CoV and SARS-CoV-2 dysregulated gene expression related to ion transport and cell homeostasis. Decreased expression of cystic fibrosis transmembrane conductance regulator (CFTR) mRNA, essential for alveolar edema resolution, was shown. Reduced CFTR mRNA levels were associated with edema accumulation in the alveoli of mice infected with SARS-CoV and SARS-CoV-2. Compounds that increased CFTR expression and activity, significantly reduced SARS-CoV-2 growth in cultured cells and protected against mouse infection, suggesting that E protein virulence is mediated by a decreased CFTR expression. IMPORTANCE Three highly pathogenic human CoVs have been identified: SARS-CoV, MERS-CoV, and SARS-CoV-2. The E protein PBMs of these three CoVs were virulence factors. Gene expression patterns associated with the different PBM motifs in the lungs of infected mice were analyzed by deep sequencing. E protein PBM motif of SARS-CoV and SARS-CoV-2 dysregulated the expression of genes related to ion transport and cell homeostasis. A decrease in the mRNA expression of the cystic fibrosis transmembrane conductance regulator (CFTR), which is essential for edema resolution, was observed. The reduction of CFTR mRNA levels was associated with edema accumulation in the lungs of mice infected with SARS-CoV-2. Compounds that increased the expression and activity of CFTR drastically reduced the production of SARS-CoV-2 and protected against its infection in a mice model. These results allowed the identification of cellular targets for the selection of antivirals.

Nature of viruses and pandemics: Coronaviruses.

Coronaviruses (CoVs) have the largest genome among RNA viruses and store large amounts of information without genome integration as they replicate in the cell cytoplasm. The replication of the virus is a continuous process, whereas the transcription of the subgenomic mRNAs is a discontinuous one, involving a template switch, which resembles a high frequency recombination mechanism that may favor virus genome variability. The origin of the three deadly human CoVs SARS-CoV, MERS-CoV and SARS-CoV-2 are zoonotic events. SARS-CoV-2 has incorporated in its spike protein a furine proteolytic site that facilitates the activation of the virus in any tissue, making this CoV strain highly polytropic and pathogenic. Using MERS-CoV as a model, a propagation-deficient RNA replicon was generated by removing E protein gene (essential for viral morphogenesis and involved in virulence), and accessory genes 3, 4a, 4b and 5 (responsible for antagonism of the innate immune response) to attenuate the virus: MERS-CoV-Δ[3,4a,4b,5,E]. This RNA replicon is strongly attenuated and elicits sterilizing protection after a single immunization in transgenic mice with the receptor for MERS-CoV, making it a promising vaccine candidate for this virus and an interesting platform for vector-based vaccine development. A strategy could be developed for the design of RNA replicon vaccines for other human pathogenic coronaviruses.

Incidence of COVID-19 in 902 Patients With Immunomediated Inflammatory Diseases Treated With Biologics and Targeted Synthetic Disease-Modifying Antirheumatic Drugs-Findings From the BIOCOVID Study.

OBJECTIVES: The aim of this study was to examine the incidence of coronavirus disease 2019 (COVID-19) among patients with immunomediated inflammatory diseases (IMIDs) treated with biologic or targeted synthetic disease-modifying antirheumatic drugs (bDMARDs and tsDMARDs) and to evaluate the influence of either IMIDs or related therapies on the incidence and evolution of COVID-19. METHODS: This observational, cross-sectional study was conducted from January 31, 2020, to May 15, 2020. Data of 902 patients were obtained from clinical records in hospitals, primary care units, and community pharmacies. Inclusion criteria were adults with IMIDs treated with bDMARDs or tsDMARDs who started therapy 3 months prior to study commencement. Patients with poor adherence to treatments were excluded. COVID-19 was classified as "definitive" (severe acute respiratory syndrome coronavirus 2 polymerase chain reaction [PCR]-positive), "possible" (characteristic symptoms and negative PCR), and "suspected" (characteristic symptoms but PCR not performed). RESULTS: COVID-19 was diagnosed in 70 patients (11 definitive, 19 possible, and 40 suspected). The cumulative incidence of definitive COVID-19 was 1.2%. When considering all cases, the incidence was 7.8%. Patients on biosimilars tumor necrosis factor blockers were more likely to have a diagnosis of COVID-19 (odds ratio, 2.308; p < 0.001). Patients on anti-B-cell therapies had a lower incidence of infections (p = 0.046). Low rates of hospitalization (14.3%), pneumonia (14.3%), death (2.9%), or thrombosis (2.9%) were observed, and 94.3% of patients recovered. CONCLUSIONS: The cumulative incidence of confirmed cases of COVID-19 was similar to the general population, with generally low hospitalization, intensive care management, and mortality rates. COVID-19 incidence was less frequent in patients with more severe immunosuppression.

Clinical Characteristics, Frailty, and Mortality of Residents With COVID-19 in Nursing Homes of a Region of Madrid.

OBJECTIVES: To describe the clinical characteristics, 30-day mortality, and associated factors of patients living in nursing homes (NH) with COVID-19, from March 20 to June 1, 2020. DESIGN: This is a retrospective study. A geriatric hospital-based team acted as a consultant and coordinated the care of older people living in NHs from the hospital. SETTING AND PARTICIPANTS: A total of 630 patients aged 70 and older with Coronavirus Disease 2019 COVID-19 living in 55 NHs. METHODS: A logistic regression was performed to analyze the factors associated with mortality. In addition, Kaplan-Meier curves were applied according to mortality and its associated factors using the log-rank Mantel-Cox test. RESULTS: The diagnosis of COVID-19 was mainly made by clinical compatibility (N = 430). Median age was 87 years, 64.6% were women and 45.9% were transferred to be cared for at the hospital. A total of 282 patients died (44.7%) within the 30 days of first attention by the team. A severe form of COVID-19 occurred in 473 patients, and the most frequent symptoms were dyspnea (n = 332) and altered level of consciousness (n = 301). According to multiple logistic regression, male sex (P = .019), the Clinical Frailty Score (CFS) ≥6 (P = .004), dementia (P = .012), dyspnea (P < .001), and having a severe form of COVID-19 (P = .001), were associated with mortality, whereas age and care setting were not. CONCLUSIONS AND IMPLICATIONS: Mortality of the residents living in NHs with COVID-19 was almost 45%. The altered level of consciousness as an atypical presentation of COVID-19 should be considered in this population. A severe form of the disease, present in more than three-quarters of patients, was associated with mortality, apart from the male sex, CFS ≥6, dementia, and dyspnea, whereas age and care setting were not. These findings may also help to recognize patients in which the Advance Care Planning process is especially urgent to assist in the decisions about their care.