HIV-1 infection downregulates cellular telomerase activity at nuclear compartment of lymphoblastoid T cells.

REYNOSO R; MINCES L; CASSINO L; SALOMÓN H; QUARLERI J

Toronto, Canadá

Congreso; XVI International AIDS Conference – Time to Deliver.; 2006

International AIDS Society

Background: The immunological features of HIV-1-infected individuals show many similarities to those seen in cellular ageing. The present hypothesis sustain that, through of inhibition of telomerase nuclear translocation, HIV-1 infection leads to an acceleration of the adaptive immune system ageing process, resulting in premature exhaustion of immune resources, which participates in the onset of immunodeficiency. The immunological features of HIV-1-infected individuals show many similarities to those seen in cellular ageing. The present hypothesis sustain that, through of inhibition of telomerase nuclear translocation, HIV-1 infection leads to an acceleration of the adaptive immune system ageing process, resulting in premature exhaustion of immune resources, which participates in the onset of immunodeficiency. Methods: E6 Jurkat cells were infected with HIV-1 (BH10 clone, m.o.i. 0.1) and followed during 5 days after infection. Infection kinetics and efficacy were evaluated by quantitative detection of Ag p24 in supernatants and intracellular compartment by using EIA assay and flow cytometry, respectively. Apoptosis and necrosis levels were measured by Annexin V and trypan blue at each analysis point. Ageing-related parameters evaluated included: (i) telomerase activity by using a commercial quantitative TRAP protocol which was applied to total, cytoplasmic and nuclear extracts; (ii) telomeric length (by Southern blot and further densitometry); and (iii) mRNA levels of 4 alternative spliced variants’ hTERT, and hTR by RT-PCR. All experiments were carried out by duplicate. Statistical analysis was performed assaying the Student t test. Results: The efficacy of infection reached was 20% with active viral replication during the assay. Cellular viability was > 90%. Telomeric length remains unchanged after infection as well as the level relative abundance of 4 spliced variants mRNA hTERT and, hTR. A significant difference (p<0.05) was found by comparing the telomerase activity between cytoplasmic and nuclear compartments after HIV-1 infection, remaining unchanged at total cellular extracts.The efficacy of infection reached was 20% with active viral replication during the assay. Cellular viability was > 90%. Telomeric length remains unchanged after infection as well as the level relative abundance of 4 spliced variants mRNA hTERT and, hTR. A significant difference (p<0.05) was found by comparing the telomerase activity between cytoplasmic and nuclear compartments after HIV-1 infection, remaining unchanged at total cellular extracts. Conclusions: HIV-1 infection is able to downregulate telomerase activity in the nuclear compartment of lymphoblastoid cells. This effect has not emerged by impact on its components –hTERT and hTR- at transcriptional level neither affected the telomere length but exhibited abnormal enzymatic cellular re-distribution. This hypothesis might shed new light on HIV-1 pathogenesis.HIV-1 infection is able to downregulate telomerase activity in the nuclear compartment of lymphoblastoid cells. This effect has not emerged by impact on its components –hTERT and hTR- at transcriptional level neither affected the telomere length but exhibited abnormal enzymatic cellular re-distribution. This hypothesis might shed new light on HIV-1 pathogenesis.