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

• Published in: The Journal of immunology (1950) Vol. 186; no. 5; pp. 3148 - 3155
• Main Authors: Zhou, Xueyuan, Shapiro, Leland, Fellingham, Gilbert, Willardson, Barry M, Burton, Gregory F
• Format: Journal Article
• Language: English
• Published: England 01.03.2011
• Subjects: CD4-Positive T-Lymphocytes - immunology; CD4-Positive T-Lymphocytes - metabolism; CD4-Positive T-Lymphocytes - virology; Cell Line, Tumor; Cells, Cultured; Coculture Techniques; Dendritic Cells, Follicular - immunology; Dendritic Cells, Follicular - metabolism; Dendritic Cells, Follicular - virology; HIV-1 - genetics; HIV-1 - immunology; Human immunodeficiency virus; Humans; I-kappa B Proteins - antagonists & inhibitors; I-kappa B Proteins - genetics; I-kappa B Proteins - metabolism; NF-kappa B p50 Subunit - antagonists & inhibitors; NF-kappa B p50 Subunit - metabolism; NF-KappaB Inhibitor alpha; Phosphorylation - immunology; Polyubiquitin - antagonists & inhibitors; Polyubiquitin - metabolism; RNA Interference; RNA, Viral - antagonists & inhibitors; RNA, Viral - immunology; Transcription Factor RelA - antagonists & inhibitors; Transcription Factor RelA - metabolism; Ubiquitination; Up-Regulation - immunology; Virus Replication - genetics; Virus Replication - immunology
• ISSN: 0022-1767; 1550-6606; 1550-6606
• DOI: 10.4049/jimmunol.1001358

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.