Background: In COVID-19, an uncontrolled inflammatory response might worsen lung damage, leading to acute respiratory distress syndrome (ARDS). Recent evidence points to the induction of inducible nitric oxide synthase (NOS2/iNOS) as a component of inflammatory response since NOS2 is upregulated in critical COVID-19 patients. Here, we explore the mechanisms underlying the modulation of iNOS expression in human alveolar cells. Methods: A549 WT and IRF1 KO cells were exposed to a conditioned medium of macrophages treated with SARS-CoV-2 spike S1. Additionally, the effect of IFNγ, IL-1β, IL-6, and TNFα, either alone or combined, was addressed. iNOS expression was assessed with RT-qPCR and Western blot. The effect of baricitinib and CAPE, inhibitors of JAK/STAT and NF-kB, respectively, was also investigated. Results: Treatment with a conditioned medium caused a marked induction of iNOS in A549 WT and a weak stimulation in IRF1 KO. IFNγ induced NOS2 and synergistically cooperated with IL-1β and TNFα. The inhibitory pattern of baricitinb and CAPE indicates that cytokines activate both IRF1 and NF-κB through the JAK/STAT1 pathway. Conclusions: Cytokines secreted by S1-activated macrophages markedly induce iNOS, whose expression is suppressed by baricitinib. Our findings sustain the therapeutic efficacy of this drug in COVID-19 since, besides limiting the cytokine storm, it also prevents NOS2 induction.

Cytokine-Induced iNOS in A549 Alveolar Epithelial Cells: A Potential Role in COVID-19 Lung Pathology / Barilli, Amelia; Recchia Luciani, Giulia; Visigalli, Rossana; Sala, Roberto; Soli, Maurizio; Dall'Asta, Valeria; Rotoli, Bianca Maria. - In: BIOMEDICINES. - ISSN 2227-9059. - 11:10(2023), p. 2699. [10.3390/biomedicines11102699]

Cytokine-Induced iNOS in A549 Alveolar Epithelial Cells: A Potential Role in COVID-19 Lung Pathology

Barilli, Amelia;Recchia Luciani, Giulia;Visigalli, Rossana;Sala, Roberto;Dall'Asta, Valeria
;
Rotoli, Bianca Maria
2023-01-01

Abstract

Background: In COVID-19, an uncontrolled inflammatory response might worsen lung damage, leading to acute respiratory distress syndrome (ARDS). Recent evidence points to the induction of inducible nitric oxide synthase (NOS2/iNOS) as a component of inflammatory response since NOS2 is upregulated in critical COVID-19 patients. Here, we explore the mechanisms underlying the modulation of iNOS expression in human alveolar cells. Methods: A549 WT and IRF1 KO cells were exposed to a conditioned medium of macrophages treated with SARS-CoV-2 spike S1. Additionally, the effect of IFNγ, IL-1β, IL-6, and TNFα, either alone or combined, was addressed. iNOS expression was assessed with RT-qPCR and Western blot. The effect of baricitinib and CAPE, inhibitors of JAK/STAT and NF-kB, respectively, was also investigated. Results: Treatment with a conditioned medium caused a marked induction of iNOS in A549 WT and a weak stimulation in IRF1 KO. IFNγ induced NOS2 and synergistically cooperated with IL-1β and TNFα. The inhibitory pattern of baricitinb and CAPE indicates that cytokines activate both IRF1 and NF-κB through the JAK/STAT1 pathway. Conclusions: Cytokines secreted by S1-activated macrophages markedly induce iNOS, whose expression is suppressed by baricitinib. Our findings sustain the therapeutic efficacy of this drug in COVID-19 since, besides limiting the cytokine storm, it also prevents NOS2 induction.
2023
Cytokine-Induced iNOS in A549 Alveolar Epithelial Cells: A Potential Role in COVID-19 Lung Pathology / Barilli, Amelia; Recchia Luciani, Giulia; Visigalli, Rossana; Sala, Roberto; Soli, Maurizio; Dall'Asta, Valeria; Rotoli, Bianca Maria. - In: BIOMEDICINES. - ISSN 2227-9059. - 11:10(2023), p. 2699. [10.3390/biomedicines11102699]
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11381/2963652
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