Effect of Antioxidants on the Production of MCP-1 Chemokine by EA.hy926 Cells in Response to IL-6.

An elevated level of circulatory interleukin 6 (IL-6) is a biomarker for cytokine storm of various etiologies, including COVID-19, and contributes to poor prognosis. Vascular endothelial cells are one of the main targets of pathological action of IL-6. IL-6 activates the trans-signaling pathway via the formation of the IL-6/sIL-6Ra/gp130 receptor complex and subsequent activation of the JAK/STAT3 signaling pathway and PI3K/AKT and MEK/ERK kinases in some cases. Previously, it was shown by the authors' group and other researchers that reactive oxygen species (ROS), including mitochondrial ROS (mito-ROS), contribute to the induction of IL-6 expression in the endothelium, mainly due to increased activation of the transcription factor NF-kB. We have also shown that the mitochondria-targeted antioxidant SkQ1 (Plastoquinolyl-10(6'-decyltriphenyl)phosphonium) prevented tumor necrosis factor (TNF)-induced cytokine storm and death in mice. In the aortas of these animals, SkQ1 also prevented the increase in the expression of NF-kB-dependent genes, including the cytokine IL-6 and the chemokine MCP-1. In the current work, the hypothesis of mito-ROS involvement in the IL-6-signaling-mediated proinflammatory gene expression in endothelial cells is tested. SkQ1 suppressed the expression and secretion of the MCP-1 chemokine, induced by IL-6 in combination with sIL-6-Ra, but not the expression of ICAM-1 adhesion molecules in EA.hy926 human endothelial cells. Using specific inhibitors, the authors have shown that, in EA.hy926 cells, IL-6-induced expression of MCP-1 and ICAM-1 depends on the signaling protein and transcription activator STAT3 and, in some cases, on JNK, PI3K, and MEK1/2 kinases and is independent of p38 kinase. In this model, IL-6 induced rapid STAT3 activation, while ERK1/2 activation was less pronounced, and there was no IL-6 effect on Akt and JNK activation. SkQ1 partially suppressed STAT3 and ERK1/2 activation. Thus, we have shown that SkQ1 suppresses not only NF-kB-dependent expression of IL-6 and other proinflammatory genes but also IL-6-induced activation of JAK/STAT3 and STAT3-dependent expression of MCP-1, which probably contributes to the overall therapeutic effect of SkQ1.

COVID-19 AND OXIDATIVE STRESS

Pathogenesis of the novel coronavirus infection COVID-19 is the subject of active research around the world. COVID-19 caused by the SARS-CoV-2 is a complex disease in which interaction of the virus with target cells, action of the immune system and the body’s systemic response to these events are closely intertwined. Many respiratory viral infections, including COVID-19, cause death of the infected cells, activation of innate immune response, and secretion of inflammatory cytokines. All these processes are associated with the development of oxidative stress, which makes an important contribution to pathogenesis of the viral infections. This review analyzes information on the oxidative stress associated with the infections caused by SARS-CoV-2 and other respiratory viruses. The review also focuses on involvement of the vascular endothelium in the COVID-19 pathogenesis. Патогенез новой коронавирусной инфекции COVID-19 является предметом активного изучения во всем мире. COVID-19, вызываемый SARS-CoV-2, представляет собой сложное заболевание, в котором тесно переплетено взаимодействие вируса с клетками-мишенями, действием иммунной системы и системной реакцией организма на эти события. Многие респираторные вирусные инфекции, включая COVID-19, вызывают смерть инфицированных клеток, активацию компонентов врожденного иммунитета и секрецию цитокинов воспаления. Все эти процессы ассоциированы с развитием окислительного стресса, который вносит важный вклад в патогенез вирусных инфекций. В данном обзоре проведен анализ информации об окислительном стрессе при инфекциях, вызываемых SARS-CoV-2 и другими респираторными вирусами. Основное внимание в обзоре уделено участию сосудистого эндотелия в патогенезе COVID-19.

COVID-19 and Oxidative Stress.

Pathogenesis of the novel coronavirus infection COVID-19 is the subject of active research around the world. COVID-19 caused by the SARS-CoV-2 is a complex disease in which interaction of the virus with target cells, action of the immune system and the body's systemic response to these events are closely intertwined. Many respiratory viral infections, including COVID-19, cause death of the infected cells, activation of innate immune response, and secretion of inflammatory cytokines. All these processes are associated with the development of oxidative stress, which makes an important contribution to pathogenesis of the viral infections. This review analyzes information on the oxidative stress associated with the infections caused by SARS-CoV-2 and other respiratory viruses. The review also focuses on involvement of the vascular endothelium in the COVID-19 pathogenesis.

TRANSCRIPTION FACTOR Nrf2 AS A THERAPEUTIC TARGET FOR THE PREVENTION OF CYTOKINE STORM IN COVID-19

Nrf2 is a key transcription factor responsible for antioxidant defense in many tissues and cells, including alveolar epithelium, endothelium, and macrophages. Furthermore, Nrf2 functions as a transcriptional repressor that inhibits expression of the inflammatory cytokines in macrophages. Critically ill patients with COVID-19 infection often present signs of high oxidative stress and systemic inflammation - the leading causes of mortality. This article suggests rationale for the use of Nrf2 inducers to prevent development of an excessive inflammatory response in COVID-19 patients. Nrf2 является ключевым фактором транскрипции, ответственным за антиоксидантную защиту во многих тканях и клетках, включая альвеолярный эпителий, эндотелий и макрофаги. Кроме того, Nrf2 функционирует как транскрипционный репрессор, подавляющий экспрессию цитокинов воспаления в макрофагах. Пациенты с COVID-19 в критическом состоянии зачастую имеют чрезвычайно высокие параметры окислительного стресса и системного воспаления, которое служит одной из основных причин летальности. В данной статье представлено обоснование использования индукторов транскрипционного фактора Nrf2 для предотвращения развития избыточного воспалительного ответа при COVID-19.

Transcription Factor Nrf2 as a Potential Therapeutic Target for Prevention of Cytokine Storm in COVID-19 Patients.

Nrf2 is a key transcription factor responsible for antioxidant defense in many tissues and cells, including alveolar epithelium, endothelium, and macrophages. Furthermore, Nrf2 functions as a transcriptional repressor that inhibits expression of the inflammatory cytokines in macrophages. Critically ill patients with COVID-19 infection often present signs of high oxidative stress and systemic inflammation - the leading causes of mortality. This article suggests rationale for the use of Nrf2 inducers to prevent development of an excessive inflammatory response in COVID-19 patients.