Dataset Information

Integrins are not essential for entry of coxsackievirus A9 into SW480 human colon adenocarcinoma cells.

ABSTRACT: Coxsackievirus A9 (CV-A9) is a pathogenic enterovirus type within the family Picornaviridae. CV-A9 infects A549 human epithelial lung carcinoma cells by attaching to the ?V?6 integrin receptor through a highly conserved Arg-Gly-Asp (RGD) motif, which is located at the exposed carboxy-terminus of the capsid protein VP1 detected in all studied clinical isolates. However, genetically-modified CV-A9 that lacks the RGD motif (CV-A9-RGDdel) has been shown to be infectious in some cell lines but not in A549, suggesting that RGD-mediated integrin binding is not always essential for efficient entry of CV-A9.Two cell lines, A549 and SW480, were used in the study. SW480 was the study object for the integrin-independent entry and A549 was used as the control for integrin-dependent entry. Receptor levels were quantitated by cell sorting and quantitative PCR. Antibody blocking assay and siRNA silencing of receptor-encoding genes were used to block virus infection. Peptide phage display library was used to identify peptide binders to CV-A9. Immunofluorescence and confocal microscopy were used to visualize the virus infection in the cells.We investigated the receptor use and early stages of CV-A9 internalization to SW480 human epithelial colon adenocarcinoma cells. Contrary to A549 infection, we showed that both CV-A9 and CV-A9-RGDdel internalized into SW480 cells and that function-blocking anti-?V integrin antibodies had no effect on the binding and entry of CV-A9. Whereas siRNA silencing of ?6 integrin subunit had no influence on virus infection in SW480, silencing of ?2-microglobulin (?2M) inhibited the virus infection in both cell lines. By using a peptide phage display screening, the virus-binding peptide identical to the N-terminal sequence of HSPA5 protein was identified and shown to block the virus infection in both A549 and SW480 cell lines. HSPA5 was also found to co-localize with CV-A9 at the SW480 cell periphery during the early stages of infection by confocal microscopy.The data suggest that while ?V?6 integrin is essential for CV-A9 in A549 cell line, it is not required in SW480 cell line in which ?2M and HSPA5 alone are sufficient for CV-A9 infection. This suggests that the choice of CV-A9 receptor(s) is dependent on the tissue/cellular environment.

SUBMITTER: Heikkila O

PROVIDER: S-EPMC5069866 | biostudies-literature | 2016 Oct

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Integrins are not essential for entry of coxsackievirus A9 into SW480 human colon adenocarcinoma cells.

Heikkilä Outi O Merilahti Pirjo P Hakanen Marika M Karelehto Eveliina E Alanko Jonna J Sukki Maria M Kiljunen Saija S Susi Petri P

Virology journal 20161018 1

<h4>Background</h4>Coxsackievirus A9 (CV-A9) is a pathogenic enterovirus type within the family Picornaviridae. CV-A9 infects A549 human epithelial lung carcinoma cells by attaching to the αVβ6 integrin receptor through a highly conserved Arg-Gly-Asp (RGD) motif, which is located at the exposed carboxy-terminus of the capsid protein VP1 detected in all studied clinical isolates. However, genetically-modified CV-A9 that lacks the RGD motif (CV-A9-RGDdel) has been shown to be infectious in some ce ...[more]

PMID: 27756316

Similar Datasets

Project description:UnlabelledCoxsackievirus A9 (CVA9) is a member of the human enterovirus B species in the Enterovirus genus of the family Picornaviridae. According to earlier studies, CVA9 binds to αVβ3 and αVβ6 integrins on the cell surface and utilizes β2-microglobulin, dynamin, and Arf6 for internalization. However, the structures utilized by the virus for internalization and uncoating are less well understood. We show here, based on electron microscopy, that CVA9 is found in multivesicular structures 2 h postinfection (p.i.). A neutral red labeling assay revealed that uncoating occurs mainly around 2 h p.i., while double-stranded RNA is found in the cytoplasm after 3 h p.i. The biogenesis of multivesicular bodies (MVBs) is crucial for promoting infection, as judged by the strong inhibitory effect of the wild-type form of Hrs and dominant negative form of VPS4 in CVA9 infection. CVA9 infection is dependent on phospholipase C at the start of infection, whereas Rac1 is especially important between 1 and 3 h p.i., when the virus is in endosomes. Several lines of evidence implicate that low pH does not play a role in CVA9 infection. The infection is not affected by Bafilomycin A1. In addition, CVA9 is not targeted to acidic late endosomes or lysosomes, and the MVBs accumulating CVA9 have a neutral pH. Thus, CVA9 is the second enterovirus demonstrated so far, after echovirus 1, that can trigger neutral MVBs, which are important for virus infection.ImportanceWe demonstrate here that the enterovirus coxsackievirus A9 (CVA9) uses a nonclathrin and nonacidic pathway to infect cells. CVA9 does not accumulate in conventional late endosomes or lysosomes. We found that inhibitors of phospholipase C (PLC), Rac1, and the Na(+)/H(+) exchanger decreased CVA9 infection. The PLC inhibitor acts on early entry, the Rac1 inhibitor acts between 1 and 3 h, when the virus is in endosomes, and the Na(+)/H(+) exchange inhibitor acts during various steps during the virus life cycle. The infection depends on the formation of novel neutral multivesicular bodies (MVBs), which accumulate CVA9 during the first hours of entry. Thus, CVA9 is the second enterovirus demonstrated so far, after echovirus 1, that can trigger formation of neutral MVBs. The data show that these enteroviruses favor nonacidic conditions and complex MVBs to promote virus infection.

Project description:To determine the effects of RNAi-mediated inhibition of the growth hormone receptor (GHR) gene on tumors and colon cancer cells in vivo.Construction of a eukaryotic vector for human GHR expression, the pcDNA6.2-GW/EmGFP-small interfering RNAs (siRNAs)-GHR plasmid, was used to inhibit GHR expression. Thirty-six BALB/c nude mice were randomly divided into groups and treated with normal saline (NS), recombinant plasmid (G?), growth hormone (GH), 5-fluorouracil (FU), G?+FU or G?+FU+GH. Each nude mouse was subcutaneously inoculated with 1 × 10(7) human colon cancer SW480 cells; the nude mice were weighed before inoculation and on the 2(nd), 5(th), 8(th), 11(th), 14(th) and 17(th) day after inoculation. All nude mice were sacrificed after 17 d. Each subcutaneous tumor was removed and studied. Tumor volume was measured on the 5(th), 8(th), 11(th), 14(th) and 17(th) day after inoculation. The expression of GHR protein in the tumor tissue was detected by Western blotting analysis, and the differences in GHR mRNA expression in the tumor tissue were detected by real-time quantitative reverse transcription-polymerase chain reaction.Compared to the control group, the weights of the inoculated nude mice on the 17(th) day after inoculation were: G?: 21.60 ± 0.71 g, GH: 21.64 ± 0.45 g, FU: 18.94 ± 0.47 g, FU+G?: 19.40 ± 0.60 g, G?+FU+GH: 21.04 ± 0.78 g vs NS: 20.68 ± 0.66 g, P < 0.05; the tumor volumes after the subcutaneous inoculation were: G?: 9.71 ± 3.82 mm(3), FU: 11.54 ± 2.42 mm(3), FU+G?: 11.42 ± 1.11 mm(3), G?+FU+GH: 10.47 ± 1.02 mm(3) vs NS: 116.81 ± 10.61 mm(3), P < 0.05. Compared to the GH group, the tumor volumes were significantly decreased in the experimental groups. The GHR protein expression (G?: 0.39 ± 0.02, FU: 0.40 ± 0.02, FU+G?: 0.38 ± 0.01, G?+FU+GH: 0.39 ± 0.01 vs NS: 0.94 ± 0.02, P < 0.05) and the GHR mRNA expression (G?: 14.12 ± 0.10, FU: 15.15 ± 0.44, FU+G?: 16.46 ± 0.27, G?+FU+GH: 15.37 ± 0.57 vs NS: 12.63 ± 0.14, P < 0.05) were significantly decreased and increased, respectively, in the experimental groups.Inhibition of GHR in human colon cancer SW480 cells resulted in anti-tumor effects in nude mice.

Project description:Nineteen CVA9 isolates were obtained between 2010 and 2019 from six provinces of mainland China, using the HFMD surveillance network established in China. Nucleotide sequencing revealed that the full-length VP1 of 19 CVA9 isolates was 906 bases encoding 302 amino acids. The combination of the thresholds of the phylogenetic tree and nucleotide divergence of different genotypes within the same serotype led to a value of 15-25%, and enabled CVA9 worldwide to be categorized into ten genotypes: A-J. The phylogenetic tree showed that the prototype strain was included in genotype A, and that the B, C, D, E, H, and J genotypes disappeared during virus evolution, whereas the F, I, and G genotypes showed co-circulation. Lineage G was the dominant genotype of CVA9 and included most of the strains from nine countries in Asia, North America, Oceania, and Europe. Most Chinese strains belonged to the G genotype, suggesting that the molecular epidemiology of China is consistent with that observed worldwide. The 165 partial VP1 strains (723 nt) showed a mean substitution rate of 3.27 × 10-3 substitution/site/year (95% HPD range 2.93-3.6 × 10-3), dating the tMRCA of CVA9 back to approximately 1922 (1911-1932). The spatiotemporal dynamics of CVA9 showed the spread of CVA9 obviously increased in recent years. Most CVA9 isolates originated in USA, but the epidemic areas of CVA9 are now concentrated in the Asia-Pacific region, European countries, and North America. Recombination analysis within the enterovirus B specie (59 serotypes) revealed eight recombination patterns in China at present, CVB4, CVB5, E30, CVB2, E11, HEV106, HEV85, and HEV75. E14, and E6 may act as recombinant donors in multiple regions. Comparison of temperature sensitivity revealed that temperature-insensitive strains have more amino acid substitutions in the RGD motif of the VP1 region, and the sites T283S, V284M, and R288K in the VP1 region may be related to the temperature tolerance of CVA9.

Dataset Information

Integrins are not essential for entry of coxsackievirus A9 into SW480 human colon adenocarcinoma cells.

Publications

Integrins are not essential for entry of coxsackievirus A9 into SW480 human colon adenocarcinoma cells.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets