scholarly journals Comparing Expression of OAS-RNaseL Pathway-Related Genes in SARS-CoV-2 and Similar Viruses

2021 ◽  
Author(s):  
Nikhil Chakravarty ◽  
Penelope A Edillor ◽  
Andy P Huang ◽  
Giovanni A Torres ◽  
Manal T Usmani ◽  
...  
Keyword(s):  
Innate Immune ◽  
Receptor Expression ◽  
Host Cells ◽  
Response Patterns ◽  
The Novel ◽  
Host Immune Responses ◽  
Common Response ◽  
Pathogenic Viruses ◽  
Interferon System ◽  
Important Branch

The COVID-19 pandemic, caused by the virus SARS-CoV-2, has been a major public health emergency and has caused millions of deaths worldwide to date. Due to the novel nature of the virus, efforts across the world are underway to better understand the molecular pathogenesis of SARS-CoV-2 and how it interacts with host immune responses. One important branch of the innate immune response, the interferon system, triggers the expression of many effector mechanisms known to be powerful antagonists against many pathogenic viruses. One such interferon stimulated mechanism is the OAS-RNaseL pathway, which is known to trigger the degradation of viral RNA in infected host cells. Our study seeks to utilize publicly available transcriptomic data to analyze the host cell OAS-RNaseL pathway to SARS-CoV-2 infection. We hoped to gain an understanding of the importance of the pathway in controlling SARS-CoV-2 infection and whether or not the pathway could be exploited therapeutically. Our findings demonstrated that upregulation of OAS-RNaseL pathway genes in response to SARS-CoV-2 infection varies based on cell type and appeared to correlate with ACE2 receptor expression. Pathway responses to other viruses like SARS-CoV and MERS-CoV were found to parallel those to SARS-CoV-2, suggesting common response patterns by the pathway to these viruses. Overall, these results demonstrate that the OAS-RNaseL pathway could contribute to control of SARS-CoV-2 infection. Further studies on various mechanistic actions by the pathway would need to be conducted to fully understand its role in host defense and therapy.

scholarly journals Mycobacterium ulcerans and Mycobacterium marinum: Pathogenesis, Diagnosis and Treatment

2020 ◽  
Vol 3 (1) ◽  
Author(s):  
Loh Teng-Hern Tan ◽  
Pendru Raghunath ◽  
Long Chiau Ming ◽  
Jodi Woan-Fei Law
Keyword(s):  
Soft Tissue ◽  
Immune Responses ◽  
Buruli Ulcer ◽  
Innate Immune ◽  
Mycobacterium Ulcerans ◽  
Host Cells ◽  
Soft Tissue Infections ◽  
Cutaneous Infections ◽  
Host Immune Responses ◽  
Geographical Regions

Skin and soft tissue infections are common presentations for non-tuberculous mycobacteria (NTM). The cutaneous infections caused by NTM may cause localized or diffuse lesions. M. ulcerans is one of the most identified pathogens that involves in the skin and soft tissue mycobacterial infections. Meanwhile, M. marinum, as an NTM has also become important emerging causal agents of cutaneous disease in various geographical regions. Although having common ancestry and highly similar in genetic makeup, M. ulcerans and M. marinum have differential impacts on the host innate immune system. In term pathogenesis, prolonged cell exposure to exotoxin mycolactone produced by M. ulcerans could lead to Buruli ulcer. Meanwhile, like most pathogenic mycobacteria, M. marinum evades the host immune responses by invading and replicating inside host cells and it is capable of modulating host immune responses. This article aims to provide a general overview and comparisons between the pathogenesis, diagnosis, prevention and therapeutic strategies for M. ulcerans and M. marinum.

Carbohydrate-Binding Agents: Potential of Repurposing for COVID-19 Therapy

2020 ◽  
Vol 21 (11) ◽  
pp. 1085-1096 ◽  
Author(s):  
Rajesh Kumar Gupta ◽  
Girish R. Apte ◽  
Kiran Bharat Lokhande ◽  
Satyendra Mishra ◽  
Jayanta K. Pal
Keyword(s):  
Vaccine Development ◽  
Host Cells ◽  
Carbohydrate Binding ◽  
Atypical Pneumonia ◽  
The Novel ◽  
High Infection ◽  
Binding Agents ◽  
Current Scenario ◽  
Antiviral Activities ◽  
Novel Drug

: With the emergence of the novel severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), the whole world is suffering from atypical pneumonia, which resulted in more than 559,047 deaths worldwide. In this time of crisis and urgency, the only hope comes from new candidate vaccines and potential antivirals. However, formulating new vaccines and synthesizing new antivirals are a laborious task. Therefore, considering the high infection rate and mortality due to COVID-19, utilization of previous information, and repurposing of existing drugs against valid viral targets have emerged as a novel drug discovery approach in this challenging time. The transmembrane spike (S) glycoprotein of coronaviruses (CoVs), which facilitates the virus’s entry into the host cells, exists in a homotrimeric form and is covered with N-linked glycans. S glycoprotein is known as the main target of antibodies having neutralizing potency and is also considered as an attractive target for therapeutic or vaccine development. Similarly, targeting of N-linked glycans of S glycoprotein envelope of CoV via carbohydrate-binding agents (CBAs) could serve as an attractive therapeutic approach for developing novel antivirals. CBAs from natural sources like lectins from plants, marine algae and prokaryotes and lectin mimics like Pradimicin-A (PRM-A) have shown antiviral activities against CoV and other enveloped viruses. However, the potential use of CBAs specifically lectins was limited due to unfavorable responses like immunogenicity, mitogenicity, hemagglutination, inflammatory activity, cellular toxicity, etc. Here, we reviewed the current scenario of CBAs as antivirals against CoVs, presented strategies to improve the efficacy of CBAs against CoVs; and studied the molecular interactions between CBAs (lectins and PRM-A) with Man9 by molecular docking for potential repurposing against CoVs in general, and SARSCoV- 2, in particular.

scholarly journals Cigarette Smoke Stimulates SARS-CoV-2 Internalization by Activating AhR and Increasing ACE2 Expression in Human Gingival Epithelial Cells

2021 ◽  
Vol 22 (14) ◽  
pp. 7669
Author(s):  
Cassio Luiz Coutinho Almeida-da-Silva ◽  
Harmony Matshik Dakafay ◽  
Kaitlyn Liu ◽  
David M. Ojcius
Keyword(s):  
Epithelial Cells ◽  
Oral Cavity ◽  
Cigarette Smoke ◽  
Large Body ◽  
Receptor Expression ◽  
Host Cells ◽  
Dependent Manner ◽  
Gingival Epithelial Cells ◽  
Human Gingival Epithelial Cells ◽  
Oral Cells

A large body of evidence shows the harmful effects of cigarette smoke to oral and systemic health. More recently, a link between smoking and susceptibility to coronavirus disease 2019 (COVID-19) was proposed. COVID-19 is due to infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which uses the receptor ACE2 and the protease TMPRSS2 for entry into host cells, thereby infecting cells of the respiratory tract and the oral cavity. Here, we examined the effects of cigarette smoke on the expression of SARS-CoV-2 receptors and infection in human gingival epithelial cells (GECs). We found that cigarette smoke condensates (CSC) upregulated ACE2 and TMPRSS2 expression in GECs, and that CSC activated aryl hydrocarbon receptor (AhR) signaling in the oral cells. ACE2 was known to mediate SARS-CoV-2 internalization, and we demonstrate that CSC treatment potentiated the internalization of SARS-CoV-2 pseudovirus in GECs in an AhR-dependent manner. AhR depletion using small interference RNA decreased SARS-CoV-2 pseudovirus internalization in CSC-treated GECs compared with control GECs. Our study reveals that cigarette smoke upregulates SARS-CoV-2 receptor expression and infection in oral cells. Understanding the mechanisms involved in SARS-CoV-2 infection in cells of the oral cavity may suggest therapeutic interventions for preventing viral infection and transmission.

scholarly journals Targeting Viral Surface Proteins through Structure-Based Design

Viruses ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1320
Author(s):  
Yogesh B Narkhede ◽  
Karen J Gonzalez ◽  
Eva-Maria Strauch
Keyword(s):  
Public Health ◽  
Viral Infections ◽  
Respiratory Viruses ◽  
Surface Proteins ◽  
Host Cells ◽  
Viral Fusion ◽  
Health It ◽  
Viral Particles ◽  
Pathogenic Viruses ◽  
Viral Surface

The emergence of novel viral infections of zoonotic origin and mutations of existing human pathogenic viruses represent a serious concern for public health. It warrants the establishment of better interventions and protective therapies to combat the virus and prevent its spread. Surface glycoproteins catalyzing the fusion of viral particles and host cells have proven to be an excellent target for antivirals as well as vaccines. This review focuses on recent advances for computational structure-based design of antivirals and vaccines targeting viral fusion machinery to control seasonal and emerging respiratory viruses.

scholarly journals Nuclear cGAS: sequestration and beyond

2021 ◽  
Author(s):  
Juli Bai ◽  
Feng Liu
Keyword(s):  
Innate Immune ◽  
Complex Nature ◽  
Type I ◽  
Replication Forks ◽  
The Novel ◽  
Nuclear Function ◽  
Double Stranded Dna ◽  
Open Questions ◽  
Established Role ◽  
Dependent Signaling Pathway

AbstractThe cyclic GMP-AMP (cGAMP) synthase (cGAS) has been identified as a cytosolic double stranded DNA sensor that plays a pivotal role in the type I interferon and inflammation responses via the STING-dependent signaling pathway. In the past several years, a growing body of evidence has revealed that cGAS is also localized in the nucleus where it is associated with distinct nuclear substructures such as nucleosomes, DNA replication forks, the double-stranded breaks, and centromeres, suggesting that cGAS may have other functions in addition to its role in DNA sensing. However, while the innate immune function of cGAS is well established, the non-canonical nuclear function of cGAS remains poorly understood. Here, we review our current understanding of the complex nature of nuclear cGAS and point to open questions on the novel roles and the mechanisms of action of this protein as a key regulator of cell nuclear function, beyond its well-established role in dsDNA sensing and innate immune response.

scholarly journals From Protein to Pandemic: The Transdisciplinary Approach Needed to Prevent Spillover and the Next Pandemic

Viruses ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1298
Author(s):  
Raina K. Plowright ◽  
Peter J. Hudson
Keyword(s):  
Immune Responses ◽  
Host Population ◽  
Reservoir Host ◽  
Innate Immune ◽  
Receptor Protein ◽  
The Novel ◽  
Innate Immune Responses ◽  
Transdisciplinary Approach ◽  
Sequence Of Events ◽  
Global Spread

Pandemics are a consequence of a series of processes that span scales from viral biology at 10−9 m to global transmission at 106 m. The pathogen passes from one host species to another through a sequence of events that starts with an infected reservoir host and entails interspecific contact, innate immune responses, receptor protein structure within the potential host, and the global spread of the novel pathogen through the naive host population. Each event presents a potential barrier to the onward passage of the virus and should be characterized with an integrated transdisciplinary approach. Epidemic control is based on the prevention of exposure, infection, and disease. However, the ultimate pandemic prevention is prevention of the spillover event itself. Here, we focus on the potential for preventing the spillover of henipaviruses, a group of viruses derived from bats that frequently cross species barriers, incur high human mortality, and are transmitted among humans via stuttering chains. We outline the transdisciplinary approach needed to prevent the spillover process and, therefore, future pandemics.

scholarly journals Bacterial Cyclic Dinucleotides and the cGAS–cGAMP–STING Pathway: A Role in Periodontitis?

Pathogens ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 675
Author(s):  
Samira Elmanfi ◽  
Mustafa Yilmaz ◽  
Wilson W. S. Ong ◽  
Kofi S. Yeboah ◽  
Herman O. Sintim ◽  
...  
Keyword(s):  
Immune Response ◽  
Periodontal Disease ◽  
Innate Immune ◽  
Host Cells ◽  
Type I Interferons ◽  
Type I ◽  
Vaccine Adjuvants ◽  
Cyclic Dinucleotides ◽  
Sting Pathway

Host cells can recognize cytosolic double-stranded DNAs and endogenous second messengers as cyclic dinucleotides—including c-di-GMP, c-di-AMP, and cGAMP—of invading microbes via the critical and essential innate immune signaling adaptor molecule known as STING. This recognition activates the innate immune system and leads to the production of Type I interferons and proinflammatory cytokines. In this review, we (1) focus on the possible role of bacterial cyclic dinucleotides and the STING/TBK1/IRF3 pathway in the pathogenesis of periodontal disease and the regulation of periodontal immune response, and (2) review and discuss activators and inhibitors of the STING pathway as immune response regulators and their potential utility in the treatment of periodontitis. PubMed/Medline, Scopus, and Web of Science were searched with the terms “STING”, “TBK 1”, “IRF3”, and “cGAS”—alone, or together with “periodontitis”. Current studies produced evidence for using STING-pathway-targeting molecules as part of anticancer therapy, and as vaccine adjuvants against microbial infections; however, the role of the STING/TBK1/IRF3 pathway in periodontal disease pathogenesis is still undiscovered. Understanding the stimulation of the innate immune response by cyclic dinucleotides opens a new approach to host modulation therapies in periodontology.

scholarly journals Alpha-1 antitrypsin inhibits TMPRSS2 protease activity and SARS-CoV-2 infection

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Lukas Wettstein ◽  
Tatjana Weil ◽  
Carina Conzelmann ◽  
Janis A. Müller ◽  
Rüdiger Groß ◽  
...  
Keyword(s):  
Serine Protease ◽  
Immune Defense ◽  
Innate Immune ◽  
Respiratory Pathogen ◽  
The Novel ◽  
Airway Epithelial ◽  
Protein Library ◽  
Epithelial Cultures ◽  
Alpha 1 Antitrypsin ◽  
Novel Coronavirus

AbstractSARS-CoV-2 is a respiratory pathogen and primarily infects the airway epithelium. As our knowledge about innate immune factors of the respiratory tract against SARS-CoV-2 is limited, we generated and screened a peptide/protein library derived from bronchoalveolar lavage for inhibitors of SARS-CoV-2 spike-driven entry. Analysis of antiviral fractions revealed the presence of α1-antitrypsin (α1AT), a highly abundant circulating serine protease inhibitor. Here, we report that α1AT inhibits SARS-CoV-2 entry at physiological concentrations and suppresses viral replication in cell lines and primary cells including human airway epithelial cultures. We further demonstrate that α1AT binds and inactivates the serine protease TMPRSS2, which enzymatically primes the SARS-CoV-2 spike protein for membrane fusion. Thus, the acute phase protein α1AT is an inhibitor of TMPRSS2 and SARS-CoV-2 entry, and may play an important role in the innate immune defense against the novel coronavirus. Our findings suggest that repurposing of α1AT-containing drugs has prospects for the therapy of COVID-19.

scholarly journals Emerging Roles of Protein Deamidation in Innate Immune Signaling

2016 ◽  
Vol 90 (9) ◽  
pp. 4262-4268 ◽  
Author(s):  
Jun Zhao ◽  
Junhua Li ◽  
Simin Xu ◽  
Pinghui Feng
Keyword(s):  
Immune Responses ◽  
Innate Immune ◽  
Microbial Pathogens ◽  
Biological Processes ◽  
Innate Immune Responses ◽  
Immune Signaling ◽  
Host Immune Responses ◽  
Innate Immune Signaling ◽  
Enzyme Deficient ◽  
Signaling Components

Protein deamidation has been considered a nonenzymatic process associated with protein functional decay or “aging.” Recent studies implicate protein deamidation in regulating signal transduction in fundamental biological processes, such as innate immune responses. Work investigating gammaherpesviruses and bacterial pathogens indicates that microbial pathogens deploy deamidases or enzyme-deficient homologues (pseudoenzymes) to induce deamidation of key signaling components and evade host immune responses. Here, we review studies on protein deamidation in innate immune signaling and present several imminent questions concerning the roles of protein deamidation in infection and immunity.

Angiotensin Converting Enzyme 2 (ACE2) Expression in the Visual System

2021 ◽  
Author(s):  
James M. Hill ◽  
Christian Clement ◽  
L. Arceneaux ◽  
Walter Lukiw
Keyword(s):  
Signal Processing ◽  
Angiotensin Converting Enzyme ◽  
Occipital Lobe ◽  
Cell Types ◽  
Receptor Expression ◽  
Host Cells ◽  
Visual Signal ◽  
Converting Enzyme ◽  
Angiotensin Converting Enzyme 2 ◽  
The Brain

Abstract Background: Multiple lines of evidence currently indicate that the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)gains entry into human host cells via a high-affinity interaction with the angiotensin-converting enzyme 2 (ACE2) transmembrane receptor. Research has further shown the widespread expression of the ACE2 receptor on the surface of many different immune, non-immune and neural host cell types, and that SARS-CoV-2 has there markable capability to attack many different types of human-host cells simultaneously. One principal neuroanatomical region for highACE2 expression patterns occurs in the brainstem, an area of the brain containing regulatory centers for respiration, and this may in part explain the predisposition of many COVID-19 patients to respiratory distress. Early studies also indicated extensive ACE2 expression in the whole eye and the brain’s visual circuitry. In this study we analyzed ACE2 receptor expression at the mRNA and protein level in multiple cell types involved in human vision, including cell types of the external eye and several deep brain regions known to be involved in the processing of visual signals.Methods: ACE2 mRNA and protein analysis; multiple eye and brain cells and tissues; gamma32P-adenosine tri-phosphate ([γ-32P]dATP) radiolabeled probes; Northern analysis; ELISA.Results: The four main findings were: (i)that many different optical and neural cell types of the human visual system provide receptors essential for SARS-CoV-2 invasion; (ii)the remarkable ubiquity of ACE2 presence in cells of the eye and anatomical regions of the brain involved in visual signal processing; (iii)that ACE2 receptor expression in different ocular cell types and visual processing centers of the brain provide multiple compartments for SARS-CoV-2 infiltration; and (iv)a gradient of increasing ACE2 expression from the anterior surface of the eye to the visual signal processing areas of the occipital lobe and the primary visual neocortex.Conclusion: A gradient of ACE2 expression from the eye surface to the occipital lobe provide the SARS-CoV-2 virus a novel pathway from the outer eye into deeper anatomical regions of the brain involved in vision. These findings may explain, in part, the many recently reported neuro-ophthalmic manifestations of SARS-CoV-2infection in COVID-19 affected patients.

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