Apoptotic DNA fragmentation, and itsin vitro prevention by nicotinamide, in lymphocytes from HIV-1-seropositive patients and in HIV-1-infected MT-4 cells

Abstract

Apoptosis seems to play an important role in the decline of CD4+ T-cells in patients infected with HIV-1. Moreover, extensive interest in apoptosis comes from the observation that it correlates both with the progression and the severity of HIV-1 infection. A cross-sectional study was made to evaluate whether such correlation may also extend to the early phases of ex vivo apoptosis, after 20 h of culture. DNA fragmentation, a parameter associated with apoptosis, was evaluated with the terminal deoxynucleotidyl-transferase-mediated dUTP nick end labelling (TUNEL) technique, which preferentially labels apoptosis in comparison to necrosis. The results obtained indicate that a negative correlation exists between the proportion of lymphocytes exhibiting DNA strand breaks and the absolute number of CD4+ T-cells per microliter. DNA fragmentation was significantly higher in patients with AIDS or advanced HIV-1 infection as compared to asymptomatic patients or seronegative individuals. No significant difference was found in relation to antiretroviral therapy. Furthermore, the addition of nicotinamide to the cultures significantly reduced DNA fragmentation of both in vitro HIV-1-infected MT-4 cells and lymphocytes from six HIV-1-seropositive individuals. The results of this study confirm that DNA fragmentation, as an early marker of apoptosis, correlates with the severity of HIV-1 infection and suggest that nicotinamide may be involved in the modulation of HIV-1-related apoptosis.

Response of a simian immunodeficiency virus (SIVmac251) to raltegravir: a basis for a new treatment for simian AIDS and an animal model for studying lentiviral persistence during antiretroviral therapy

“…We used syncytia counts in CEMx174 cells as a measure of lentiviral replication. SIVmac251 replication induces syncytia at an earlier time point as compared to the cytopathic effect induced in MT-4 cells, in which lentiviral replication mostly induces apoptotic and necrotic cell death [29]. The effectiveness of syncytia counts as a parameter for detection of the antiretroviral effects was confirmed by correlation analyses of syncytium formation and viral core antigen production in the presence of antiretroviral drugs (an example using raltegravir is given in the additional material [see Additional file 2]).…”

Glycolysis downregulation is a hallmark of HIV‐1 latency and sensitizes infected cells to oxidative stress

“…Profoundly linked to oxidative stress, iron metabolism has been shown to lead, through its manipulation, to the selective death of infected cells (Savarino et al , 1999 ; Hanauske‐Abel et al , 2013 ; Shytaj et al , 2020 ), but its clinical applications have so far been hampered by off‐target effects. Other pathways that might have therapeutic potential in the setting of HIV‐1 infection are autophagy (Loucif et al , 2021 ) and the intertwined tryptophan/kynurenine (reviewed in: Routy et al , 2015 ) and nicotinamide metabolism (Savarino et al , 1997 ; Lebouché et al , 2020 ). The importance of understanding the relationship between cell metabolism and the infection is emphasized by a recent case of long‐term control of HIV‐1 without ART (Oral Abstracts from the 23r d International AIDS Conference, 2020 ).…”

Glycolysis downregulation is a hallmark of HIV-1 latency and sensitizes infected cells to oxidative stress

“…Moreover, these observations may shed new light on the previously reported contribution of nicotinamide to proviral escape from latency (Samer et al, 2020) and viability of HIV-1-infected cells (Savarino et al, 1997).…”