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CCR6 functions as a new coreceptor for limited primary human and simian immunodeficiency viruses.

Islam S, Shimizu N, Hoque SA, Jinno-Oue A, Tanaka A, Hoshino H - PLoS ONE (2013)

Bottom Line: When CCR6 was transduced there, the resultant NP-2/CD4/CCR6 cells became susceptible to HIV-1HAN2, HIV-2MIR and SIVsmE660, indicating coreceptor roles of CCR6.Conversely, CCR6-origin SIVsmE660 clones resulted two amino acid changes in the V1 region and one change in the C2 region.Together, the results describe CCR6 as an independent coreceptor for HIV and SIV in strain-specific manner.

View Article: PubMed Central - PubMed

Affiliation: Department of Virology and Preventive Medicine, Gunma University Graduate School of Medicine, Maebashi, Gunma, Japan.

ABSTRACT
More than 12 chemokine receptors (CKRs) have been identified as coreceptors for the entry of human immunodeficiency virus type 1 (HIV-1), type 2 (HIV-2), and simian immunodeficiency viruses (SIVs) into target cells. The expression of CC chemokine receptor 6 (CCR6) on Th17 cells and regulatory T cells make the host cells vulnerable to HIV/SIV infection preferentially. However, only limited information is available concerning the specific role of CCR6 in HIV/SIV infection. We examined CCR6 as a coreceptor candidate in this study using NP-2 cell line-based in-vitro studies. Normally, CD4-transduced cell line, NP-2/CD4, is strictly resistant to all HIV/SIV infection. When CCR6 was transduced there, the resultant NP-2/CD4/CCR6 cells became susceptible to HIV-1HAN2, HIV-2MIR and SIVsmE660, indicating coreceptor roles of CCR6. Viral antigens in infected cells were detected by IFA and confirmed by detection of proviral DNA. Infection-induced syncytia in NP-2/CD4/CCR6 cells were detected by Giemsa staining. Amount of virus release through CCR6 has been detected by RT assay in spent culture medium. Sequence analysis of proviral DNA showed two common amino acid substitutions in the C2 envelope region of HIV-2MIR clones propagated through NP-2/CD4/CCR6 cells. Conversely, CCR6-origin SIVsmE660 clones resulted two amino acid changes in the V1 region and one change in the C2 region. The substitutions in the C2 region for HIV-2MIR and the V1 region of SIVsmE660 may confer selection advantage for CCR6-use. Together, the results describe CCR6 as an independent coreceptor for HIV and SIV in strain-specific manner. The alteration of CCR6 uses by viruses may influence the susceptibility of CD4+ CCR6+ T-cells and dendritic cell subsets in vivo and therefore, is important for viral pathogenesis in establishing latent infections, trafficking, and transmission. However, clinical relevance of CCR6 as coreceptor in HIV/SIV infections should be investigated further.

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Phylogenetic analyses of coreceptor binding regions of chemokine receptors.(A) Schematic diagram was made to present amino terminal region (NTR) and extracellular loops (ECLs) of CCR6 structure. Subsequently three phylogenetic trees were prepared based on NTR, ECL2 and ECL3 of 20 chemokine receptors (CKRs). Branch of CCR6 on each tree was indicated by arrow. CKRs that are reported to function as HIV/SIV coreceptors are marked by “▲”. The phylogenetic tree for NTRs of CKRs (B) showed CCR6 homologous to CXCR6. On the other hand, the tree made from ECL2s of all CKRs (C) placed CCR6 close to CX3CR1. However, the tree prepared from ECL3s of all CKRs (D) positioned CCR6 similar to CXCR6 again.
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pone-0073116-g005: Phylogenetic analyses of coreceptor binding regions of chemokine receptors.(A) Schematic diagram was made to present amino terminal region (NTR) and extracellular loops (ECLs) of CCR6 structure. Subsequently three phylogenetic trees were prepared based on NTR, ECL2 and ECL3 of 20 chemokine receptors (CKRs). Branch of CCR6 on each tree was indicated by arrow. CKRs that are reported to function as HIV/SIV coreceptors are marked by “▲”. The phylogenetic tree for NTRs of CKRs (B) showed CCR6 homologous to CXCR6. On the other hand, the tree made from ECL2s of all CKRs (C) placed CCR6 close to CX3CR1. However, the tree prepared from ECL3s of all CKRs (D) positioned CCR6 similar to CXCR6 again.

Mentions: To find whether a common property is present among the HIV/SIV coreceptors, we examined and analysed the amino acid sequence of NH2-terminal region (NTR) of CCR6, CCR5, CXCR4 and other CKRs. Almost all reported HIV/SIV coreceptors possess tyrosine (Y) residues accompanied by aspartic acid (D), asparagine (N) or gluatamic acid (E) residues in their NTRs and tyrosine are reported to play important roles in their coreceptor activities [6,49]. The latest reported coreceptor, N-formylpeptides, FPRL1 that contains two tyrosine residues plus glutamic acids in its NTR, was shown to support the entry of various HIV/SIV strains and isolates [35]. Likely, CCR6, the latest reported coreceptor, also contains three Ys, four Ds and four Es in its NTR (Figure 5A). To discover the relatedness of CCR6-NTR among CKRs, we constructed a phylogenetic tree taking all 20 CKR-NTRs using BioEdit program (Version 7). In the tree, the NTRs were clustered into several distinct branches according to the subfamilies of CKRs. We found CCR6 to form a closely related cluster with CXCR6 (Figure 5B), which was reported HIV- and SIV-coreceptor [39,48], therefore justified its candidacy. Beside NTR, the second or third extracellular loop of coreceptor also play important role in HIV entry [50,51]. Therefore, we prepared two other phylogenetic trees using second and third ECLs of CCR6 to the respective positions of other CKRs. The second ECL of CCR6 placed it close to CX3CR1 (Figure 5C), which is another reported coreceptor [41]. The phylogenetic tree drawn from third ECLs clustered CCR6 again to CXCR6 (Figure 5D), hence reassured its position close to a HIV-coreceptor. Therefore, the hypothesis based on amino acid analyses of NTR and ECLs of CCR6 presented itself a HIV/SIV-coreceptor, as supported by our laboratory investigations.


CCR6 functions as a new coreceptor for limited primary human and simian immunodeficiency viruses.

Islam S, Shimizu N, Hoque SA, Jinno-Oue A, Tanaka A, Hoshino H - PLoS ONE (2013)

Phylogenetic analyses of coreceptor binding regions of chemokine receptors.(A) Schematic diagram was made to present amino terminal region (NTR) and extracellular loops (ECLs) of CCR6 structure. Subsequently three phylogenetic trees were prepared based on NTR, ECL2 and ECL3 of 20 chemokine receptors (CKRs). Branch of CCR6 on each tree was indicated by arrow. CKRs that are reported to function as HIV/SIV coreceptors are marked by “▲”. The phylogenetic tree for NTRs of CKRs (B) showed CCR6 homologous to CXCR6. On the other hand, the tree made from ECL2s of all CKRs (C) placed CCR6 close to CX3CR1. However, the tree prepared from ECL3s of all CKRs (D) positioned CCR6 similar to CXCR6 again.
© Copyright Policy
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC3757016&req=5

pone-0073116-g005: Phylogenetic analyses of coreceptor binding regions of chemokine receptors.(A) Schematic diagram was made to present amino terminal region (NTR) and extracellular loops (ECLs) of CCR6 structure. Subsequently three phylogenetic trees were prepared based on NTR, ECL2 and ECL3 of 20 chemokine receptors (CKRs). Branch of CCR6 on each tree was indicated by arrow. CKRs that are reported to function as HIV/SIV coreceptors are marked by “▲”. The phylogenetic tree for NTRs of CKRs (B) showed CCR6 homologous to CXCR6. On the other hand, the tree made from ECL2s of all CKRs (C) placed CCR6 close to CX3CR1. However, the tree prepared from ECL3s of all CKRs (D) positioned CCR6 similar to CXCR6 again.
Mentions: To find whether a common property is present among the HIV/SIV coreceptors, we examined and analysed the amino acid sequence of NH2-terminal region (NTR) of CCR6, CCR5, CXCR4 and other CKRs. Almost all reported HIV/SIV coreceptors possess tyrosine (Y) residues accompanied by aspartic acid (D), asparagine (N) or gluatamic acid (E) residues in their NTRs and tyrosine are reported to play important roles in their coreceptor activities [6,49]. The latest reported coreceptor, N-formylpeptides, FPRL1 that contains two tyrosine residues plus glutamic acids in its NTR, was shown to support the entry of various HIV/SIV strains and isolates [35]. Likely, CCR6, the latest reported coreceptor, also contains three Ys, four Ds and four Es in its NTR (Figure 5A). To discover the relatedness of CCR6-NTR among CKRs, we constructed a phylogenetic tree taking all 20 CKR-NTRs using BioEdit program (Version 7). In the tree, the NTRs were clustered into several distinct branches according to the subfamilies of CKRs. We found CCR6 to form a closely related cluster with CXCR6 (Figure 5B), which was reported HIV- and SIV-coreceptor [39,48], therefore justified its candidacy. Beside NTR, the second or third extracellular loop of coreceptor also play important role in HIV entry [50,51]. Therefore, we prepared two other phylogenetic trees using second and third ECLs of CCR6 to the respective positions of other CKRs. The second ECL of CCR6 placed it close to CX3CR1 (Figure 5C), which is another reported coreceptor [41]. The phylogenetic tree drawn from third ECLs clustered CCR6 again to CXCR6 (Figure 5D), hence reassured its position close to a HIV-coreceptor. Therefore, the hypothesis based on amino acid analyses of NTR and ECLs of CCR6 presented itself a HIV/SIV-coreceptor, as supported by our laboratory investigations.

Bottom Line: When CCR6 was transduced there, the resultant NP-2/CD4/CCR6 cells became susceptible to HIV-1HAN2, HIV-2MIR and SIVsmE660, indicating coreceptor roles of CCR6.Conversely, CCR6-origin SIVsmE660 clones resulted two amino acid changes in the V1 region and one change in the C2 region.Together, the results describe CCR6 as an independent coreceptor for HIV and SIV in strain-specific manner.

View Article: PubMed Central - PubMed

Affiliation: Department of Virology and Preventive Medicine, Gunma University Graduate School of Medicine, Maebashi, Gunma, Japan.

ABSTRACT
More than 12 chemokine receptors (CKRs) have been identified as coreceptors for the entry of human immunodeficiency virus type 1 (HIV-1), type 2 (HIV-2), and simian immunodeficiency viruses (SIVs) into target cells. The expression of CC chemokine receptor 6 (CCR6) on Th17 cells and regulatory T cells make the host cells vulnerable to HIV/SIV infection preferentially. However, only limited information is available concerning the specific role of CCR6 in HIV/SIV infection. We examined CCR6 as a coreceptor candidate in this study using NP-2 cell line-based in-vitro studies. Normally, CD4-transduced cell line, NP-2/CD4, is strictly resistant to all HIV/SIV infection. When CCR6 was transduced there, the resultant NP-2/CD4/CCR6 cells became susceptible to HIV-1HAN2, HIV-2MIR and SIVsmE660, indicating coreceptor roles of CCR6. Viral antigens in infected cells were detected by IFA and confirmed by detection of proviral DNA. Infection-induced syncytia in NP-2/CD4/CCR6 cells were detected by Giemsa staining. Amount of virus release through CCR6 has been detected by RT assay in spent culture medium. Sequence analysis of proviral DNA showed two common amino acid substitutions in the C2 envelope region of HIV-2MIR clones propagated through NP-2/CD4/CCR6 cells. Conversely, CCR6-origin SIVsmE660 clones resulted two amino acid changes in the V1 region and one change in the C2 region. The substitutions in the C2 region for HIV-2MIR and the V1 region of SIVsmE660 may confer selection advantage for CCR6-use. Together, the results describe CCR6 as an independent coreceptor for HIV and SIV in strain-specific manner. The alteration of CCR6 uses by viruses may influence the susceptibility of CD4+ CCR6+ T-cells and dendritic cell subsets in vivo and therefore, is important for viral pathogenesis in establishing latent infections, trafficking, and transmission. However, clinical relevance of CCR6 as coreceptor in HIV/SIV infections should be investigated further.

Show MeSH
Related in: MedlinePlus