Innate immune sensing of coronavirus and viral evasion strategies

Abstract

The innate immune system is the first line of the host defense program against pathogens and harmful substances. Antiviral innate immune responses can be triggered by multiple cellular receptors sensing viral components. The activated innate immune system produces interferons (IFNs) and cytokines that perform antiviral functions to eliminate invading viruses. Coronaviruses are single-stranded, positive-sense RNA viruses that have a broad range of animal hosts. Coronaviruses have evolved multiple means to evade host antiviral immune responses. Successful immune evasion by coronaviruses may enable the viruses to adapt to multiple species of host organisms. Coronavirus transmission from zoonotic hosts to humans has caused serious illnesses, such as severe acute respiratory syndrome (SARS), Middle East respiratory syndrome (MERS), and coronavirus disease-2019 (COVID-19), resulting in global health and economic crises. In this review, we summarize the current knowledge of the mechanisms underlying host sensing of and innate immune responses against coronavirus invasion, as well as host immune evasion strategies of coronaviruses.

The SARS-CoV-2/Receptor Axis in Heart and Blood Vessels: A Crisp Update on COVID-19 Disease with Cardiovascular Complications

“…Despite antiviral attributes, these viral containing macrophages surprisingly serve to relocate by egressing from the lung tissues to the other organs [ 158 ]. The macrophage contained SARS-CoV-2 RNA could trigger TLR7, the RNA sensors, through the adaptor MyD88 and RIG-I through the adaptor MAVS, both of which induce type 1 IFNs production that is activated via the transcription factors STAT1, STAT2 and IRF9, leading to upregulation of caspase-11 and other IFN-inducible proteins [ 159 ]. Concomitant activation of caspase-1 and inflammasome pathway leads to macrophage pyroptosis by cleaving gasdermin that forms pores on the plasma membrane to facilitate IL-1β release [ 160 ].…”

The proximal proteome of 17 SARS-CoV-2 proteins links to disrupted antiviral signaling and host translation

“…Other viral gene products, generally termed accessory factors, are believed to be dedicated to manipulating the host environment to foster viral replication [ 7 ]. One of the main functions of accessory factors is to block host antiviral response [ 8 ] though many viral proteins are multifunctional and structural proteins can also affect host signaling pathways [ 9 ]. Other coronaviruses have also been shown to block host translation [ 10 , 11 ], inhibit interferon signaling [ 12 , 13 ], antagonize viral RNA sensing [ 14 , 15 ], and degrade host mRNAs [ 16 ].…”

“…Other viral gene products, generally termed accessory factors, are believed to be dedicated to manipulating the host environment to foster viral replication [7]. One of the main functions of accessory factors is to block host antiviral response [8] though many viral proteins are multifunctional and structural proteins can also affect host signaling pathways [9].…”

Recent Advances of COVID-19 Modeling Based on Regenerative Medicine

“…SARS-CoV-2 possesses several proteins such as the NSP family, ORF proteins, M, N that are important in evading the immune system through several ways like cleaving host mRNA, inhibiting inflammatory cytokines production, sequestering viral RNA, inducing apoptosis or direct cytopathic effects, and inhibiting host proteins translation. Discussing these mechanisms in detail is beyond the scope of this article ( Kasuga et al, 2021 ). Different factors have been known to be associated with poor prognosis of ARDS in COVID-19 patients, lymphopenia and cytokine storm are the two most important factors ( Pourbagheri-Sigaroodi et al, 2020 ).…”