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J Immunol ; 207(5): 1275-1287, 2021 09 01.
Article in English | MEDLINE | ID: covidwho-1771322


The airway epithelial cells (AECs) lining the conducting passageways of the lung secrete a variety of immunomodulatory factors. Among these, PGE2 limits lung inflammation and promotes bronchodilation. By contrast, IL-6 drives intense airway inflammation, remodeling, and fibrosis. The signaling that differentiates the production of these opposing mediators is not understood. In this study, we find that the production of PGE2 and IL-6 following stimulation of human AECs by the damage-associated molecular pattern extracellular ATP shares a common requirement for Ca2+ release-activated Ca2+ (CRAC) channels. ATP-mediated synthesis of PGE2 required activation of metabotropic P2Y2 receptors and CRAC channel-mediated cytosolic phospholipase A2 signaling. By contrast, ATP-evoked synthesis of IL-6 occurred via activation of ionotropic P2X receptors and CRAC channel-mediated calcineurin/NFAT signaling. In contrast to ATP, which elicited the production of both PGE2 and IL-6, the uridine nucleotide, UTP, stimulated PGE2 but not IL-6 production. These results reveal that human AECs employ unique receptor-specific signaling mechanisms with CRAC channels as a signaling nexus to regulate release of opposing immunomodulatory mediators. Collectively, our results identify P2Y2 receptors, CRAC channels, and P2X receptors as potential intervention targets for airway diseases.

Dinoprostone/metabolism , Inflammation/immunology , Interleukin-6/metabolism , Respiratory Mucosa/metabolism , Adenosine Triphosphate/pharmacokinetics , Alarmins/metabolism , Calcium Release Activated Calcium Channels/metabolism , Cells, Cultured , Humans , Immunomodulation , Interleukin-6/genetics , NFATC Transcription Factors/metabolism , Phospholipases A2/metabolism , Receptors, Purinergic P2X/metabolism , Respiratory Mucosa/pathology , Signal Transduction , Uracil Nucleotides/metabolism
Science ; 375(6577): 161-167, 2022 Jan 14.
Article in English | MEDLINE | ID: covidwho-1648160


The COVID-19 pandemic has underscored the critical need for broad-spectrum therapeutics against respiratory viruses. Respiratory syncytial virus (RSV) is a major threat to pediatric patients and older adults. We describe 4'-fluorouridine (4'-FlU, EIDD-2749), a ribonucleoside analog that inhibits RSV, related RNA viruses, and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), with high selectivity index in cells and human airway epithelia organoids. Polymerase inhibition within in vitro RNA-dependent RNA polymerase assays established for RSV and SARS-CoV-2 revealed transcriptional stalling after incorporation. Once-daily oral treatment was highly efficacious at 5 milligrams per kilogram (mg/kg) in RSV-infected mice or 20 mg/kg in ferrets infected with different SARS-CoV-2 variants of concern, initiated 24 or 12 hours after infection, respectively. These properties define 4'-FlU as a broad-spectrum candidate for the treatment of RSV, SARS-CoV-2, and related RNA virus infections.

Antiviral Agents/pharmacology , COVID-19/drug therapy , Respiratory Syncytial Virus Infections/drug therapy , Respiratory Syncytial Virus, Human/drug effects , SARS-CoV-2/drug effects , Uracil Nucleotides/pharmacology , Administration, Oral , Animals , Antiviral Agents/administration & dosage , Antiviral Agents/metabolism , COVID-19/virology , Cell Line , Coronavirus RNA-Dependent RNA Polymerase/metabolism , Disease Models, Animal , Female , Ferrets , Humans , Mice , Mice, Inbred BALB C , Microbial Sensitivity Tests , Mononegavirales/drug effects , Mononegavirales/physiology , RNA-Dependent RNA Polymerase/metabolism , Respiratory Mucosa/virology , Respiratory Syncytial Virus Infections/virology , Respiratory Syncytial Virus, Human/genetics , Respiratory Syncytial Virus, Human/physiology , SARS-CoV-2/genetics , SARS-CoV-2/physiology , Transcription, Genetic , Uracil Nucleotides/administration & dosage , Uracil Nucleotides/metabolism , Virus Replication/drug effects