scholarly journals Coronavirus Infection-Associated Cell Death Signaling and Potential Therapeutic Targets

Molecules ◽  
2021 ◽  
Vol 26 (24) ◽  
pp. 7459
Author(s):  
Rittibet Yapasert ◽  
Patompong Khaw-on ◽  
Ratana Banjerdpongchai
Keyword(s):  
Cell Death ◽  
Host Cell ◽  
Viral Entry ◽  
Nonstructural Protein ◽  
Cathepsin L ◽  
Proteasome Inhibitors ◽  
Specific Inhibitor ◽  
Structural Protein ◽  
Reading Frame ◽  
Nonstructural Protein 1

COVID-19 is the name of the disease caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection that occurred in 2019. The virus–host-specific interactions, molecular targets on host cell deaths, and the involved signaling are crucial issues, which become potential targets for treatment. Spike protein, angiotensin-converting enzyme 2 (ACE2), cathepsin L-cysteine peptidase, transmembrane protease serine 2 (TMPRSS2), nonstructural protein 1 (Nsp1), open reading frame 7a (ORF7a), viral main protease (3C-like protease (3CLpro) or Mpro), RNA dependent RNA polymerase (RdRp) (Nsp12), non-structural protein 13 (Nsp13) helicase, and papain-like proteinase (PLpro) are molecules associated with SARS-CoV infection and propagation. SARS-CoV-2 can induce host cell death via five kinds of regulated cell death, i.e., apoptosis, necroptosis, pyroptosis, autophagy, and PANoptosis. The mechanisms of these cell deaths are well established and can be disrupted by synthetic small molecules or natural products. There are a variety of compounds proven to play roles in the cell death inhibition, such as pan-caspase inhibitor (z-VAD-fmk) for apoptosis, necrostatin-1 for necroptosis, MCC950, a potent and specific inhibitor of the NLRP3 inflammasome in pyroptosis, and chloroquine/hydroxychloroquine, which can mitigate the corresponding cell death pathways. However, NF-κB signaling is another critical anti-apoptotic or survival route mediated by SARS-CoV-2. Such signaling promotes viral survival, proliferation, and inflammation by inducing the expression of apoptosis inhibitors such as Bcl-2 and XIAP, as well as cytokines, e.g., TNF. As a result, tiny natural compounds functioning as proteasome inhibitors such as celastrol and curcumin can be used to modify NF-κB signaling, providing a responsible method for treating SARS-CoV-2-infected patients. The natural constituents that aid in inhibiting viral infection, progression, and amplification of coronaviruses are also emphasized, which are in the groups of alkaloids, flavonoids, terpenoids, diarylheptanoids, and anthraquinones. Natural constituents derived from medicinal herbs have anti-inflammatory and antiviral properties, as well as inhibitory effects, on the viral life cycle, including viral entry, replication, assembly, and release of COVID-19 virions. The phytochemicals contain a high potential for COVID-19 treatment. As a result, SARS-CoV-2-infected cell death processes and signaling might be of high efficacy for therapeutic targeting effects and yielding encouraging outcomes.

scholarly journals Molecular analysis of the dengue virus type 1 and 2 in Brazil based on sequences of the genomic envelope-nonstructural protein 1 junction region

2004 ◽  
Vol 46 (3) ◽  
pp. 145-152 ◽  
Author(s):  
Cecília Luiza S. Santos ◽  
Maria Anice M. Sallum ◽  
Peter G. Foster ◽  
Iray Maria Rocco
Keyword(s):  
Sequence Data ◽  
Nonstructural Protein ◽  
Phylogenetic Analyses ◽  
Decomposition Analysis ◽  
Structural Protein ◽  
Network Graph ◽  
Junction Region ◽  
Split Decomposition ◽  
Genotype Iii ◽  
Nonstructural Protein 1

The genomic sequences of the Envelope-Non-Structural protein 1 junction region (E/NS1) of 84 DEN-1 and 22 DEN-2 isolates from Brazil were determined. Most of these strains were isolated in the period from 1995 to 2001 in endemic and regions of recent dengue transmission in São Paulo State. Sequence data for DEN-1 and DEN-2 utilized in phylogenetic and split decomposition analyses also include sequences deposited in GenBank from different regions of Brazil and of the world. Phylogenetic analyses were done using both maximum likelihood and Bayesian approaches. Results for both DEN-1 and DEN-2 data are ambiguous, and support for most tree bipartitions are generally poor, suggesting that E/NS1 region does not contain enough information for recovering phylogenetic relationships among DEN-1 and DEN-2 sequences used in this study. The network graph generated in the split decomposition analysis of DEN-1 does not show evidence of grouping sequences according to country, region and clades. While the network for DEN-2 also shows ambiguities among DEN-2 sequences, it suggests that Brazilian sequences may belong to distinct subtypes of genotype III.

Influenza A viruses balance ER stress with host protein synthesis shutoff

2021 ◽  
Vol 118 (36) ◽  
pp. e2024681118
Author(s):  
Beryl Mazel-Sanchez ◽  
Justyna Iwaszkiewicz ◽  
Joao P. P. Bonifacio ◽  
Filo Silva ◽  
Chengyue Niu ◽  
...  
Keyword(s):  
Viral Replication ◽  
Er Stress ◽  
Host Cell ◽  
Messenger Rna ◽  
Influenza A ◽  
Nonstructural Protein ◽  
Host Protein ◽  
Stress Induction ◽  
Nonstructural Protein 1

Excessive production of viral glycoproteins during infections poses a tremendous stress potential on the endoplasmic reticulum (ER) protein folding machinery of the host cell. The host cell balances this by providing more ER resident chaperones and reducing translation. For viruses, this unfolded protein response (UPR) offers the potential to fold more glycoproteins. We postulated that viruses could have developed means to limit the inevitable ER stress to a beneficial level for viral replication. Using a relevant human pathogen, influenza A virus (IAV), we first established the determinant for ER stress and UPR induction during infection. In contrast to a panel of previous reports, we identified neuraminidase to be the determinant for ER stress induction, and not hemagglutinin. IAV relieves ER stress by expression of its nonstructural protein 1 (NS1). NS1 interferes with the host messenger RNA processing factor CPSF30 and suppresses ER stress response factors, such as XBP1. In vivo viral replication is increased when NS1 antagonizes ER stress induction. Our results reveal how IAV optimizes glycoprotein expression by balancing folding capacity.

scholarly journals Porcine Parvovirus Infection Causes Pig Placenta Tissue Damage Involving Nonstructural Protein 1 (NS1)-Induced Intrinsic ROS/Mitochondria-Mediated Apoptosis

Viruses ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 389 ◽  
Author(s):  
Zhang ◽  
Fan ◽  
Li ◽  
Liang ◽  
Huo ◽  
...  
Keyword(s):  
Host Cell ◽  
Cell Apoptosis ◽  
Nonstructural Protein ◽  
Placental Tissue ◽  
Reproductive Failure ◽  
Porcine Parvovirus ◽  
Nonstructural Protein 1 ◽  
Host Cell Apoptosis ◽  
Tissue Damages ◽  
Induced Apoptosis

Porcine parvovirus (PPV) is an important pathogen causing reproductive failure in pigs. PPV-induced cell apoptosis has been recently identified as being involved in PPV-induced placental tissue damages resulting in reproductive failure. However, the molecular mechanism was not fully elucidated. Here we demonstrate that PPV nonstructural protein 1 (NS1) can induce host cell apoptosis and death, thereby indicating the NS1 may play a crucial role in PPV-induced placental tissue damages and reproductive failure. We have found that NS1-induced apoptosis was significantly inhibited by caspase 9 inhibitor, but not caspase 8 inhibitor, and transfection of NS1 gene into PK-15 cells significantly inhibited mitochondria-associated antiapoptotic molecules Bcl-2 and Mcl-1 expressions and enhanced proapoptotic molecules Bax, P21, and P53 expressions, suggesting that NS1-induced apoptosis is mainly through the mitochondria-mediated intrinsic apoptosis pathway. We also found that both PPV infection and NS1 vector transfection could cause host DNA damage resulting in cell cycle arrest at the G1 and G2 phases, trigger mitochondrial ROS accumulation resulting in mitochondria damage, and therefore, induce the host cell apoptosis. This study provides a molecular basis for elucidating PPV-induced cell apoptosis and reproductive failure.

scholarly journals Mapping the Rubella Virus Subgenomic Promoter

2002 ◽  
Vol 76 (7) ◽  
pp. 3189-3201 ◽  
Author(s):  
Wen-Pin Tzeng ◽  
Teryl K. Frey
Keyword(s):  
Rubella Virus ◽  
Fluorescent Protein ◽  
Nonstructural Protein ◽  
Infectious Clone ◽  
Start Site ◽  
Structural Protein ◽  
Reading Frame ◽  
Gfp Gene ◽  
Green Fluorescent ◽  
Positive Strand Rna

ABSTRACT Rubella virus (RUB), the sole member of the Rubivirus genus in the Togaviridae family of positive-strand RNA viruses, synthesizes a single subgenomic (SG) RNA containing sequences from the 3′ end of the genomic RNA including the open reading frame (ORF) that encodes the virion proteins. The synthesis of SG RNA is initiated internally on a negative-strand, genome-length template at a site known as the SG promoter (SGP). Mapping the RUB SGP was initiated by using an infectious cDNA vector, dsRobo402/GFP, in which the region containing the SGP was duplicated (K. V. Pugachev, W.-P. Tzeng, and T. K. Frey, J. Virol. 74:10811-10815, 2000). In dsRobo402/GFP, the 5′-proximal nonstructural protein ORF (NS-ORF) is followed by the first SGP (SGP-1), the green fluorescent protein (GFP) gene, the second SGP (SGP-2), and the structural protein ORF. The duplicated SGP, SGP-2, contained nucleotides (nt) −175 to +76 relative to the SG start site, including the 3′ 127 nt of the NS-ORF and 47 nt between the NS-ORF and the SG start site. 5′ Deletions of SGP-2 to nt −40 (9 nt beyond the 3′ end of the NS-ORF) resulted in a wild-type (wt) phenotype in terms of virus replication and RNA synthesis. Deletions beyond this point impaired viability; however, the analysis was complicated by homologous recombination between SGP-1 and SGP-2 that resulted in deletion of the GFP gene and resurrection of viable virus with one SGP. Since the NS-ORF region was not necessary for SGP activity, subsequent mapping was done by using both replicon vectors, RUBrep/GFP and RUBrep/CAT, in which the SP-ORF is replaced with the reporter GFP and chloramphenical acetyltransferase genes, respectively, and the wt infectious clone, Robo402. In the replicon vectors, 5′ deletions to nt −26 resulted in the synthesis of SG RNA. In the infectious clone, deletions through nt −28 gave rise to viable virus. A series of short internal deletions confirmed that the region between nt −28 and the SG start site was essential for viability and showed that the repeated UCA triplet at the 5′ end of SG RNA was also required. Thus, the minimal SGP maps from nt −26 through the SG start site and appears to extend to at least nt +6, although a larger region is required for the generation of virus with a wt phenotype. Interestingly, while the positioning of the RUB SGP immediately adjacent the SG start site is thus similar to that of members of the genus Alphavirus, the other genus in the Togaviridae family, it does not include a region of nucleotide sequence homology with the alphavirus SGP that is located between nt −48 and nt −23 with respect to the SG start site in the RUB genome.

scholarly journals Structural analysis of SARS-Cov-2 nonstructural protein 1 polymorphisms found in the Brazilian Amazon

2021 ◽  
Vol 246 (21) ◽  
pp. 2332-2337
Author(s):  
Fernando Berton Zanchi ◽  
Luis André Mariúba ◽  
Valdinete Nascimento ◽  
Victor Souza ◽  
André Corado ◽  
...  
Keyword(s):  
Tertiary Structure ◽  
Nonstructural Protein ◽  
Variable Region ◽  
Infection Process ◽  
Terminal Region ◽  
Structural Protein ◽  
Intermediate Variable ◽  
Nsp1 Gene ◽  
Nonstructural Protein 1 ◽  
Two Samples

The coronavirus disease COVID-19 has been the cause of millions of deaths worldwide. Among the SARS-CoV-2 proteins, the non-structural protein 1 (NSP1) has great importance during the virus infection process and is present in both alpha and beta-CoVs. Therefore, monitoring of NSP1 polymorphisms is crucial in order to understand their role during infection and virus-induced pathogenicity. Herein, we analyzed how mutations detected in the circulating SARS-CoV-2 in the population of the city of Manaus, Amazonas state, Brazil could modify the tertiary structure of the NSP1 protein. Three mutations were detected in the SARS-CoV-2 NSP1 gene: deletion of the amino acids KSF from positions 141 to 143 (delKSF), SARS-CoV-2, lineage B.1.195; and two substitutions, R29H and R43C, SARS-CoV-2 lineage B.1.1.28 and B.1.1.33, respectively. The delKSF was found in 47 samples, whereas R29H and R43C were found in two samples, one for each mutation. The NSP1 structures carrying the mutations R43C and R29H on the N-terminal portion (e.g. residues 10 to 127) showed minor backbone divergence compared to the Wuhan model. However, the NSP1 C-terminal region (residues 145 to 180) was severely affected in the delKSF and R29H mutants. The intermediate variable region (residues 144 to 148) leads to changes in the C-terminal region, particularly in the delKSF structure. New investigations must be carried out to analyze how these changes affect NSP1 activity during the infection. Our results reinforce the need for continuous genomic surveillance of SARS-CoV-2 to better understand virus evolution and assess the potential impact of the viral mutations on the approved vaccines and future therapies.

Nanobead-Based Screening Method for Antibody Pairing of Dengue Virus Nonstructural Protein-1

2021 ◽  
Vol 17 (9) ◽  
pp. 1788-1797
Author(s):  
Zhixin Chen ◽  
Shuzhen He ◽  
Ruixian Xu ◽  
Qinqin Han ◽  
Xueshan Xia ◽  
...  
Keyword(s):  
Monoclonal Antibodies ◽  
Dengue Virus ◽  
Nonstructural Protein ◽  
Point Of Care ◽  
Screening Method ◽  
Viral Disease ◽  
Structural Protein ◽  
Nonstructural Protein 1 ◽  
Detection Technology ◽  
Virus Serotype

Dengue fever is a classic mosquito viral disease. Dengue virus non-structural protein-1 as a membrane-associated homologous dimer anchored to the surface of infected cells and also secreted into the blood. The nonstructural protein-1 levels are related to disease severity, and the presence of nonstructural protein-1 secreted from cells to the serum of people infected with the dengue virus is an early marker of infection. Paired antibodies are key in the establishment of rapid detection technology. In this study, the prepared recombinant nonstructural protein-1 protein of dengue virus serotype 3 was purified by the prokaryotic expression, and prepared monoclonal antibodies by cell fusion. A method for paired antibody screening was established based on the N-hydroxy succinimide-nanobeads and the prepared monoclonal antibodies. A simple and rapid point-of-care system integrating the paired antibodies and lateral flow assay was established to verify the screened antibody pairs. The results confirmed that the antibody pair screening method based on N-hydroxy succinimide-nanobeads is feasible.

scholarly journals Nuclear and Nucleolar Targeting of Influenza A Virus NS1 Protein: Striking Differences between Different Virus Subtypes

2007 ◽  
Vol 81 (11) ◽  
pp. 5995-6006 ◽  
Author(s):  
Krister Melén ◽  
Leena Kinnunen ◽  
Riku Fagerlund ◽  
Niina Ikonen ◽  
Karen Y. Twu ◽  
...  
Keyword(s):  
Host Cell ◽  
Influenza A Virus ◽  
Influenza A ◽  
Rna Binding ◽  
Nonstructural Protein ◽  
Ns1 Protein ◽  
Nonstructural Protein 1 ◽  
Importin Α ◽  
Localization Signal ◽  
Ns1a Protein

ABSTRACT Influenza A virus nonstructural protein 1 (NS1A protein) is a virulence factor which is targeted into the nucleus. It is a multifunctional protein that inhibits host cell pre-mRNA processing and counteracts host cell antiviral responses. We show that the NS1A protein can interact with all six human importin α isoforms, indicating that the nuclear translocation of NS1A protein is mediated by the classical importin α/β pathway. The NS1A protein of the H1N1 (WSN/33) virus has only one N-terminal arginine- or lysine-rich nuclear localization signal (NLS1), whereas the NS1A protein of the H3N2 subtype (Udorn/72) virus also has a second C-terminal NLS (NLS2). NLS1 is mapped to residues 35 to 41, which also function in the double-stranded RNA-binding activity of the NS1A protein. NLS2 was created by a 7-amino-acid C-terminal extension (residues 231 to 237) that became prevalent among human influenza A virus types isolated between the years 1950 to 1987. NLS2 includes basic amino acids at positions 219, 220, 224, 229, 231, and 232. Surprisingly, NLS2 also forms a functional nucleolar localization signal NoLS, a function that was retained in H3N2 type virus NS1A proteins even without the C-terminal extension. It is likely that the evolutionarily well-conserved nucleolar targeting function of NS1A protein plays a role in the pathogenesis of influenza A virus.

scholarly journals Analysis of the 3′ cis-Acting Elements of Rubella Virus by Using Replicons Expressing a Puromycin Resistance Gene

2004 ◽  
Vol 78 (5) ◽  
pp. 2553-2561 ◽  
Author(s):  
Min-Hsin Chen ◽  
Ilya Frolov ◽  
Joseph Icenogle ◽  
Teryl K. Frey
Keyword(s):  
Rubella Virus ◽  
Nonstructural Protein ◽  
Relative Survival ◽  
Open Reading Frame ◽  
In Vitro Translation ◽  
Minus Strand ◽  
Structural Protein ◽  
Coding Region ◽  
Reading Frame

ABSTRACT A rubella virus (RUB) replicon, RUBrep/PAC, was constructed and used to map the 3′ cis-acting elements (3′ CSE) of the RUB genome required for RUB replication. The RUBrep/PAC replicon had the structural protein open reading frame partially replaced by a puromycin acetyltransferase (PAC) gene. Cells transfected with RUBrep/PAC transcripts expressed the PAC gene from the subgenomic RNA, were rendered resistant to puromycin, and thus survived selection with this drug. The relative survival following puromycin selection of cells transfected with transcripts from RUBrep/PAC constructs with mutations in the 3′ CSE varied. The 3′ region necessary for optimal relative survival consisted of the 3′ 305 nucleotides (nt), a region conserved in RUB defective-interfering RNAs, and thus this region constitutes the 3′ CSE. Within the 3′ CSE, deletions in the ∼245 nt that overlap the 3′ end of the E1 gene resulted in reduced relative survivals, ranging from 20 to <1% of the parental replicon survival level while most mutations within the ∼60-nt 3′ untranslated region (UTR) were lethal. None of the 3′ CSE mutations affected in vitro translation of the nonstructural protein open reading frame (which is 5′ proximal in the genome and encodes the enzymes involved in virus RNA replication). In cells transfected with replicons with 3′ CSE mutations that survived antibiotic selection (i.e., those with mutations in the region of the 3′ CSE that overlaps the E1 coding region), the amount of replicon-specific minus-strand RNA was uniform; however, the accumulation of both plus-strand RNA species, genomic and subgenomic, varied widely, indicating that this region of the RUB 3′ CSE affects plus-strand RNA accumulation rather than minus-strand RNA synthesis.

scholarly journals Involvement of Caspase-9 in the Inhibition of Necrosis of RAW 264 Cells Infected with Mycobacterium tuberculosis

2007 ◽  
Vol 75 (6) ◽  
pp. 2894-2902 ◽  
Author(s):  
Ryosuke Uchiyama ◽  
Ikuo Kawamura ◽  
Takao Fujimura ◽  
Michiko Kawanishi ◽  
Kohsuke Tsuchiya ◽  
...  
Keyword(s):  
Cell Death ◽  
Mycobacterium Tuberculosis ◽  
Host Cell ◽  
Specific Inhibitor ◽  
Host Cells ◽  
Ros Generation ◽  
Caspase 9 ◽  
Host Cell Death ◽  
Intracellular Ros ◽  
Infected Cells

ABSTRACT In order to know how caspases contribute to the intracellular fate of Mycobacterium tuberculosis and host cell death in the infected macrophages, we examined the effect of benzyloxycarbonyl-Val-Ala-Asp(OMe)-fluoromethane (z-VAD-fmk), a broad-spectrum caspase inhibitor, on the growth of M. tuberculosis H37Rv in RAW 264 cells. In the cells treated with z-VAD-fmk, activation of caspase-8, caspase-3/7, and caspase-9 was clearly suppressed, and DNA fragmentation of the infected cells was also reduced. Under this experimental condition, it was found that the treatment markedly inhibited bacterial growth inside macrophages. The infected cells appeared to undergo cell death of the necrosis type in the presence of z-VAD-fmk. We further found that z-VAD-fmk treatment resulted in the generation of intracellular reactive oxygen species (ROS) in the infected cells. By addition of a scavenger of ROS, the host cell necrosis was inhibited and the intracellular growth of H37Rv was significantly restored. Among inhibitors specific for each caspase, only the caspase-9-specific inhibitor enhanced the generation of ROS and induced necrosis of the infected cells. Furthermore, we found that severe necrosis was induced by infection with H37Rv but not H37Ra in the presence of z-VAD-fmk. Caspase-9 activation was also detected in H37Rv-infected cells, but H37Ra never induced such caspase-9 activation. These results indicated that caspase-9, which was activated by infection with virulent M. tuberculosis, contributed to the inhibition of necrosis of the infected host cells, presumably through suppression of intracellular ROS generation.

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