scholarly journals Current Understanding of the Innate Control of Toll-Like Receptors in Response to SARS-CoV-2 Infection

Viruses ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 2132
Author(s):  
Hi Eun Jung ◽  
Heung Kyu Lee

The global coronavirus disease 2019 (COVID-19) pandemic, caused by severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) infection, threatens the entire world. It has affected every aspect of life and increased the burden on both healthcare and socioeconomic systems. Current studies have revealed that excessive inflammatory immune responses are responsible for the severity of COVID-19, which suggests that anti-inflammatory drugs may be promising therapeutic treatments. However, there are currently a limited number of approved therapeutics for COVID-19. Toll-like receptors (TLRs), which recognize microbial components derived from invading pathogens, are involved in both the initiation of innate responses against SARS-CoV-2 infection and the hyperinflammatory phenotype of COVID-19. In this review, we provide current knowledge on the pivotal role of TLRs in immune responses against SARS-CoV-2 infection and demonstrate the potential effectiveness of TLR-targeting drugs on the control of hyperinflammation in patients with COVID-19.

2021 ◽  
Vol 5 (4) ◽  
pp. 195-221
Author(s):  
Katarzyna Nazimek ◽  

<abstract> <p>At present, special efforts are being made to develop the strategies allowing for activation of long-lasting antigen-specific immune tolerance in therapy of allergic and autoimmune diseases. Some of these therapeutic approaches are aimed at modulating cell functions at genetic level by using miRNA-based and miRNA-targeting treatments. Simultaneously, the crucial role of extracellular vesicles as natural miRNA conveyors is highlighted for induction of antigen-specific immune tolerance, especially that they appear to be easily manipulatable for therapeutic applications. Among other immune-related miRNAs, miR-150 is getting special attention as it is differently expressed by immune cells at various stages of their maturation and differentiation. In addition, miR-150 is involved in different signaling cascades orchestrating humoral and cell-mediated mechanisms of both innate and adaptive immune responses. Therefore, miR-150 is considered a master regulator of immunity in mammals. Currently, physiological miR-150-dependent regulatory circuits and causes of their malfunctioning that underlie the pathogenesis of allergic and autoimmune disorders are being unraveled. Thus, present review summarizes the current knowledge of the role of miR-150 in the pathogenesis and complications of these diseases. Furthermore, the involvement of miR-150 in regulation of immune responses to allergens and self-antigens and in induction of antigen-specific immune tolerance is discussed with the special emphasis on the therapeutic potential of this miRNA.</p> </abstract>


2017 ◽  
Vol 17 (2) ◽  
pp. 58-63 ◽  
Author(s):  
Chi Kit Au ◽  
Tin Lok Lai ◽  
Cheuk Wan Yim

AbstractMajority of rheumatic diseases are complex and multifactorial in etiology. Emerging studies has suggested that the change of human microbiota, especially in the gut, play a pivotal role in its pathogenesis. Dysequilibrium of the gut microbiota triggers the imbalance between pro- and anti- inflammatory immune responses and results in different rheumatic manifestations, such as rheumatoid arthritis (RA) and spondyloarthritis (SpA). In this article, current and future role of the human gut microbiota in rheumatic diseases are discussed.


2021 ◽  
Vol 12 ◽  
Author(s):  
Chiel van Geffen ◽  
Astrid Deißler ◽  
Markus Quante ◽  
Harald Renz ◽  
Dominik Hartl ◽  
...  

The immune system is receiving increasing attention for interstitial lung diseases, as knowledge on its role in fibrosis development and response to therapies is expanding. Uncontrolled immune responses and unbalanced injury-inflammation-repair processes drive the initiation and progression of idiopathic pulmonary fibrosis. The regulatory immune system plays important roles in controlling pathogenic immune responses, regulating inflammation and modulating the transition of inflammation to fibrosis. This review aims to summarize and critically discuss the current knowledge on the potential role of regulatory immune cells, including mesenchymal stromal/stem cells, regulatory T cells, regulatory B cells, macrophages, dendritic cells and myeloid-derived suppressor cells in idiopathic pulmonary fibrosis. Furthermore, we review the emerging role of regulatory immune cells in anti-fibrotic therapy and lung transplantation. A comprehensive understanding of immune regulation could pave the way towards new therapeutic or preventive approaches in idiopathic pulmonary fibrosis.


2019 ◽  
Vol 12 (576) ◽  
pp. eaav2060 ◽  
Author(s):  
Soichiro Yoshikawa ◽  
Masatsugu Oh-hora ◽  
Ryota Hashimoto ◽  
Toshihisa Nagao ◽  
Louis Peters ◽  
...  

Basophils have nonredundant roles in various immune responses that require Ca2+influx. Here, we examined the role of two Ca2+sensors, stromal interaction molecule 1 and 2 (STIM1 and STIM2), in basophil activation. We found that loss of STIM1, but not STIM2, impaired basophil IL-4 production after stimulation with immunoglobulin E (IgE)–containing immune complexes. In contrast, when basophils were stimulated with IL-3, loss of STIM2, but not STIM1, reduced basophil IL-4 production. This difference in STIM proteins was associated with distinct time courses of Ca2+influx and transcription of theIl4gene that were elicited by each stimulus. Similarly, basophil-specific STIM1 expression was required for IgE-driven chronic allergic inflammation in vivo, whereas STIM2 was required for IL-4 production after combined IL-3 and IL-33 treatment in mice. These data indicate that STIM1 and STIM2 have differential roles in the production of IL-4, which are stimulus dependent. Furthermore, these results illustrate the vital role of STIM2 in basophils, which is often considered to be less important than STIM1.


2017 ◽  
Vol 2017 ◽  
pp. 1-18 ◽  
Author(s):  
Carlos Rosales ◽  
Eileen Uribe-Querol

One hundred years have passed since the death of Élie Metchnikoff (1845–1916). He was the first to observe the uptake of particles by cells and realized the importance of this process for the host response to injury and infection. He also was a strong advocate of the role of phagocytosis in cellular immunity, and with this he gave us the basis for our modern understanding of inflammation and the innate and acquired immune responses. Phagocytosis is an elegant but complex process for the ingestion and elimination of pathogens, but it is also important for the elimination of apoptotic cells and hence fundamental for tissue homeostasis. Phagocytosis can be divided into four main steps: (i) recognition of the target particle, (ii) signaling to activate the internalization machinery, (iii) phagosome formation, and (iv) phagolysosome maturation. In recent years, the use of new tools of molecular biology and microscopy has provided new insights into the cellular mechanisms of phagocytosis. In this review, we present a general view of our current knowledge on phagocytosis. We emphasize novel molecular findings, particularly on phagosome formation and maturation, and discuss aspects that remain incompletely understood.


2020 ◽  
Vol 9 (8) ◽  
pp. 2586 ◽  
Author(s):  
Eilidh Bruce ◽  
Fenella Barlow-Pay ◽  
Roxanna Short ◽  
Arturo Vilches-Moraga ◽  
Angeline Price ◽  
...  

Coronavirus disease 2019 (COVID-19) infection causes acute lung injury, resulting from aggressive inflammation initiated by viral replication. There has been much speculation about the potential role of non-steroidal inflammatory drugs (NSAIDs), which increase the expression of angiotensin-converting enzyme 2 (ACE2), a binding target for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) to enter the host cell, which could lead to poorer outcomes in COVID-19 disease. The aim of this study was to examine the association between routine use of NSAIDs and outcomes in hospitalised patients with COVID-19. This was a multicentre, observational study, with data collected from adult patients with COVID-19 admitted to eight UK hospitals. Of 1222 patients eligible to be included, 54 (4.4%) were routinely prescribed NSAIDs prior to admission. Univariate results suggested a modest protective effect from the use of NSAIDs, but in the multivariable analysis, there was no association between prior NSAID use and time to mortality (adjusted HR (aHR) = 0.89, 95% CI 0.52–1.53, p = 0.67) or length of stay (aHR 0.89, 95% CI 0.59–1.35, p = 0.58). This study found no evidence that routine NSAID use was associated with higher COVID-19 mortality in hospitalised patients; therefore, patients should be advised to continue taking these medications until further evidence emerges. Our findings suggest that NSAID use might confer a modest benefit with regard to survival. However, as this finding was underpowered, further research is required.


2020 ◽  
Vol 6 (2) ◽  
Author(s):  
Eugenio Boccalone ◽  
Veronica Maria Lanni ◽  
Valerio Massimo Magro

In 2019, a new coronavirus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), aroused the attention of the entire world. It causes an acute respiratory disease, by involving the same receptor, i.e. the angiotensin-converting enzyme 2, as that for severe acute respiratory syndrome coronavirus (SARS-CoV), mainly spreads through the respiratory tract. The clinical symptoms in patients with of SARS-CoV-2 include fever, cough, dyspnea, fatigue and in a small percentage of patients also gastrointestinal symptoms have been reported...


Author(s):  
Afaf Allaoui ◽  
Akif A. Khawaja ◽  
Oussama Badad ◽  
Mariam Naciri ◽  
Marie Lordkipanidzé ◽  
...  

AbstractPlatelets, as nonnucleated blood components, are classically recognized for their pivotal role in hemostasis. In recent years, however, accumulating evidence points to a nonhemostatic role for platelets, as active participants in the inflammatory and immune responses to microbial organisms in infectious diseases. This stems from the ability of activated platelets to secrete a plethora of immunomodulatory cytokines and chemokines, as well as directly interplaying with viral receptors. While much attention has been given to the role of the cytokine storm in the severity of the coronavirus disease 2019 (COVID-19), less is known about the contribution of platelets to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Here, we give a brief overview on the platelet contribution to antiviral immunity and response during SARS-CoV-2 infection.


Molecules ◽  
2021 ◽  
Vol 27 (1) ◽  
pp. 152
Author(s):  
Barbara Balestrieri ◽  
David Di Costanzo ◽  
Daniel F. Dwyer

Macrophages have diverse functions in the pathogenesis, resolution, and repair of inflammatory processes. Elegant studies have elucidated the metabolomic and transcriptomic profiles of activated macrophages. However, the versatility of macrophage responses in inflammation is likely due, at least in part, to their ability to rearrange their repertoire of bioactive lipids, including fatty acids and oxylipins. This review will describe the fatty acids and oxylipins generated by macrophages and their role in type 1 and type 2 immune responses. We will highlight lipidomic studies that have shaped the current understanding of the role of lipids in macrophage polarization.


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