HIV replication in CD4+ T lymphocytes in the presence and absence of follicular dendritic cells: inhibition of replication mediated by α-1-antitrypsin through altered IκBα ubiquitination.
Follicular dendritic cells (FDCs) increase HIV replication and virus production in lymphocytes by increasing the activation of NF-κB in infected cells. Because α-1-antitrypsin (AAT) decreases HIV replication in PBMCs and monocytic cells and decreases NF-κB activity, we postulated that AAT might also block FDC-mediated HIV replication. Primary CD4(+) T cells were infected with HIV and cultured with FDCs or their supernatant with or without AAT, and ensuing viral RNA and p24 production were monitored. NF-κB activation in the infected cells was also assessed. Virus production was increased in the presence of FDC supernatant, but the addition of AAT at concentrations >0.5 mg/ml inhibited virus replication. AAT blocked the nuclear translocation of NF-κB p50/p65 despite an unexpected elevation in associated phosphorylated and ubiquitinated IκBα (Ub-IκBα). In the presence of AAT, degradation of cytoplasmic IκBα was dramatically inhibited compared with control cultures. AAT did not inhibit the proteasome; however, it altered the pattern of ubiquitination of IκBα. AAT decreased IκBα polyubiquitination linked through ubiquitin lysine residue 48 and increased ubiquitination linked through lysine residue 63. Moreover, lysine reside 63-linked Ub-IκBα degradation was substantially slower than lysine residue 48-linked Ub-IκBα in the presence of AAT, correlating altered ubiquitination with a prolonged IκBα t(1/2). Because AAT is naturally occurring and available clinically, examination of its use as an inhibitory agent in HIV-infected subjects may be informative and lead to the development of similar agents that inhibit HIV replication using a novel mechanism.
Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT 84602, USA.
Xueyuan
X
Zhou
Leland
L
Shapiro
Gilbert
G
Fellingham
Barry M
BM
Willardson
Gregory F
GF
Burton
D015496:CD4-Positive T-Lymphocytes / Q000276:immunology* / Q000378:metabolism / Q000821:virology*; D045744:Cell Line, Tumor; D002478:Cells, Cultured; D018920:Coculture Techniques; D020566:Dendritic Cells, Follicular / Q000276:immunology* / Q000378:metabolism / Q000821:virology*; D015497:HIV-1 / Q000235:genetics / Q000276:immunology*; D006801:Humans; D020672:I-kappa B Proteins / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism; D000072000:NF-KappaB Inhibitor alpha; D052002:NF-kappa B p50 Subunit / Q000037:antagonists & inhibitors / Q000378:metabolism; D010766:Phosphorylation / Q000276:immunology; D025821:Polyubiquitin / Q000037:antagonists & inhibitors / Q000378:metabolism; D034622:RNA Interference; D012367:RNA, Viral / Q000037:antagonists & inhibitors* / Q000276:immunology; D051996:Transcription Factor RelA / Q000037:antagonists & inhibitors / Q000378:metabolism; D054875:Ubiquitination; D015854:Up-Regulation / Q000276:immunology; D014779:Virus Replication / Q000235:genetics / Q000276:immunology*
D020672:I-kappa B Proteins; D052002:NF-kappa B p50 Subunit; C000606204:NFKBIA protein, human; D012367:RNA, Viral; D051996:Transcription Factor RelA; D025821:Polyubiquitin; D000072000:NF-KappaB Inhibitor alpha
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