Increased expression of Werner and Bloom helicases in peripheral blood mononuclear cells of HIV-1 infected patients
Abstract number: R2477
Amendola A., Bordi L., D'Offizi G., Vlassi C., Lalle E., Nardacci R., Capobianchi M.
Objectives: WRN and BLM helicases are two crucial proteins involved in DNA metabolic pathways, such as cell repair, replication, and ricombination. We previously described increased levels of WRN and BLM gene expression in PBMC from HIV-infected persons (Bordi L, et al., Human Immunology 68, 2007). The role of WRN as cofactor for HIV-1 transcriprtion and replication has been also demonstrated by Sharma A, et al. (J Biol Chem 16, 2007). Aim of the study is to analyse the steady-state level of Werner (WRN) and Bloom (BLM) mRNA and protein helicases in PBMC and CD4 and CD8 positive T subsets obtained from a larger number of HIV-1 infected patients and HIV-seronegative healthy donors.
Methods: The mRNA expression level of WRN and BLM genes and wrn and blm proteins were investigated in ex-vivo PBMC obtained from 70 HIV-1-infected patients and 27 HIV-seronegative healthy donors (HD). WRN and BLM mRNAs were measured by real-time PCR; wrn and blm proteins were analysed by immunocitochemistry, both in total PBMC and in different subsets of PBMC (CD4-positive and CD8-positive T lymphocytes, CD14-positive and residual cells) isolated by magnetic beads.
Results: In total PBMC from HIV-1 infected individuals, 3.2-fold higher mean level of WRN mRNA (mean +SEM: 1.004 +0.07) has been detected in comparison to HD (0.315 +0.020) and this difference was significant (p < 0.0001). BLM mRNA mean levels were slightly higher than in controls (0.165 +0.0162 versus 0.419 +0.052, respectively), but the difference was equally significant (p = 0.018). WRN increase (but not BLM) resulted to correlate positively with CD4 and CD8 T cell absolute numbers. CD4 and CD8 T cells were the main subsets containing higher levels of WRN mRNA in HIV-infected patients (in comparison to HD), while no differences were observed within subsets from HD and HIV-infected persons for BLM. Analysis of wrn and blm proteins in different subsets are still in progress.
Conclusion: The increase in helicases expression observed in T cells from HIV-infected persons could be a mechanism aimed to prevent hyper-recombination, transformation and premature senescence in replication-competent cells, and therefore, it may be explained as a modification induced by the virus finalised to assure the host genomic integrity and an efficient viral replication.
|Session name:||18th European Congress of Clinical Microbiology and Infectious Diseases|
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