76 research outputs found
New classes of anti-HIV-1 compounds active at different stages of infection
Get PDFE’ riconosciuto che monociti/macrofagi (M/M) rappresentano un bersaglio cruciale per il virus dell’immunodeficienza umana (HIV) e giocano un ruolo chiave nella progressione patogenetica dell’infezione da HIV-1. Questo supporta la rilevanza clinica delle strategie terapeutiche in grado di interferire con la replicazione di HIV-1 nei M/M. L’importante ruolo rivestito dai M/M nella trasmissione, nella disseminazione nell’organismo e nella persistenza del virus anche in pazienti trattati con successo con terapia antiretrovirale suggerisce la necessità di identificare nuovi trattamenti contro la replicazione di HIV-1, capaci di agire a differenti stadi del ciclo virale. Obiettivo della ricerca qui presentata è stato quello di valutare l’efficacia di differenti classi di farmaci capaci di agire a diversi livelli del ciclo replicativi di HIV-1. Abbiamo dapprima studiato inibitori dell’entrata di HIV-1 che agiscono a livello della complessa sequenza di eventi che portano all’entrata del virus nella cellula bersaglio. Gli inibitori dell’entrata possono dividersi in: i) inibitori della glicoproteina virale gp120; ii) inibitori della glicoproteina gp41 (inibitori della fusione); iii) inibitori del recettore virale CD4; iv) inibitori dei principali corecettori virali CXCR4 e CCR5. Il nostro studio è stata incentrato sullo studio dell’attività antivirale di due inibitori del CCR5: DAPTA (D-Ala-Peptide T-amide) e TAK-779. I risultati ottenuti indicano che DAPTA e TAK-779 sono potenti composti anti-HIV-1 in grado di bloccare l’entrata di ceppi virali che usano il CCR5 nell’infezione dei M/M. In particolare, DAPTA è in grado di inibire la replicazione virale a concentrazioni estremamente basse. L’utilizzo di inibitori dei corecettori, come DAPTA o TAK-779, potrebbe agire in maniera sinergica col trattamento antiretrovirale nel contrastare l’infezione da HIV-1 e i danni direttamente o indirettamente indotti dal virus. Altra classe di composti capaci di inibire l’entrata di HIV-1 nelle cellule bersaglio, è rappresentata dagli agenti che legano i carboidrati (CBAs), recentemente proposti come composti innovativi che legano selettivamente i glicani della glicoproteina dell’envelope gp120 e prevengono nelle cellule dendritiche (DC) le cattura di HIV mediata dal DC-SIGN e la trasmissione dell’infezione ai linfociti T CD4+. I risultati ottenuti hanno dimostrato che le CBAs prevengono efficacemente l’infezione di R5 HIV-1 nei M/M che non esprimono livelli misurabili di DC-SIGN, mentre esprimono il recettore per il mannosio (MMR). Abbiamo anche osservato che la pre-esposizione di X4 HIV-1 alle CBAs è in grado di prevenire la cattura del virus da parte dei M/M e la conseguente formazione di sincizi nelle coculture di cellule linfocitarie C8166 non infette e M/M esposti a CBA-X4 HIV-1. Prevenendo l’entrata e quindi la replicazione virale nei M/M e riducendo la capacità degli stessi M/M di catturare e trasmettere HIV-1 ai linfociti T le CBAs potrebbero essere considerate nella selezione di farmaci microbicidi per studi clinici. Poiché i M/M rappresentano cellule cronicamente infettate, abbiamo anche studiato l’efficacia di nuovi farmaci che agiscono ad uno stadio post-integrazionale nel ciclo di replicazione di HIV-1. In particolare ci siamo focalizzati su una classe di farmaci che comprende i derivati dei quinoloni, noti antibatterici ad ampio spettro. Nei nostri esperimenti due nuovi 6-desfluoro-quinolone derivati (6-DFQs), HM-12 e HM-13, sono stati valutati per la loro attività anti-HIV-1 in cellule acutamente, cronicamente e latetemente infettate da HIV-1 e si sono rivelati agire come potenti inibitori della trascrizione virale. In un modello murino in vivo in cui i topi venivano inoculati con cellule umane patentemente infettate da HIV-1, 6-DFQs prevenivano efficacemente l’attivazione di HIV-1 guidata da TNFα. Questi composti, in grado di ridurre la replicazione virale, potrebbero essere combinati con inibitori dell’entrata, dell’integrasi o della trascrittasi inversa nel trattamento dell’infezione da HIV-1. Inoltre, poiché è noto che l’infezione da HIV-1 induce una significativa perturbazione dello stato ossidativo nei M/M, è interessante studiare nuovi farmaci capaci di contrastare il danno correlato con tale condizione di stress ossidativo. In particolare abbiamo studiato l’MnTBAP (Mn(III)tetrakis(4-benzoic acid)porphrin chloride), un catalizzatore sintetico della decomposizione del perossinitrito, in grado di ridurre la condizione di stress ossidativo dovuta al perossinitrito in M/M infetti da HIV-1. I risultati ottenuti hanno dimostrato che l’MnTBAP è in grado di inibire la replicazione e la maturazione di HIV-1 in M/M. Le caratteristiche dell’infezione di HIV-1 nei M/M potrebbero essere prese in considerazione per ideare nuove strategie terapeutiche con lo scopo di raggiungere un effetto terapeutico ottimale in tutti i compartimenti corporei in cui il virus si nasconde e replica.It is widely recognized that monocytes/macrophages (M/M) represent a crucial target of HIV-1 in the body and play a pivotal role in the pathogenic progression of the HIV-1 infection. This strongly supports the clinical relevance of therapeutic strategies able to interfere with HIV-1 replication in M/M. The important role of M/M in HIV-1 transmission, dissemination of infectious virus throughout the body, and in virus persistence, even in patients treated successfully with HAART therapy, suggests the necessity to identify new treatments against HIV-1 replication active at different stages of virus infection. HIV-1 cellular entry inhibitors are a promising class of potential anti-HIV-1/AIDS drugs. By interacting with the viral envelope glycoproteins (gp120 or gp41), and/or with CD4 or the coreceptors, these inhibitors block different steps in the complex sequence of events leading to virus–cell fusion, counteracting in this way the HIV-1 infection of the target cells. We focused on two CCR5 inhibitors, DAPTA and TAK-779, both able to inhibit the R5 HIV-1 replication in M/M. Our results indicate that DAPTA and TAK-779 are potent anti-HIV-1 compounds able to block the virus entry of R5 HIV-1 strains in M/M, suppressing viral replication in the cells. In particular, DAPTA proved to be able to inhibit the virus replication at extremely low drug concentrations. The use of coreceptor inhibitors, such as DAPTA and TAK-779, could be important to contribute to a possible synergism with other antiretroviral treatments.
Another class of compounds able to act before HIV-1 entry, is represented by carbohydrate-binding agents (CBAs). These agents are recently proposed as innovative anti-HIV compounds selectively targeting the glycans of the HIV-1 envelope glycoprotein gp120 and preventing DC-SIGN-directed HIV capture by dendritic cells (DC) and subsequent transmission of the virus to CD4+ T-lymphocytes. We now found that CBAs also efficiently prevent R5 HIV-1 infection of human primary M/M that do not measurably express DC-SIGN but markedly express the macrophage mannose-binding receptor (MMR). We observed also that pre-exposure of X4 HIV-1 to CBAs is able to prevent efficient virus capture by M/M and subsequent syncytia formation in co-cultures of uninfected CD4+ T-lymphocyte C8166 cells and CBA-X4 HIV-1 exposed M/M. The potential of CBAs to impair M/M in their capacity of hosting virus replication and chronic production of new virus particles, but also preventing M/M to efficiently capture and transmit HIV to T-lymphocytes might be an important property to be taken into consideration in the eventual choice to select microbicide candidate drugs for clinical investigation.
Since M/M represent chronically infected cells, it will be also interesting to study new drugs acting at a post-integration stage in the replication cycle of HIV-1. A unique class of drugs that may contribute to the control of the latent HIV-1 reservoir includes the quinolone derivatives, first reported as an important class of broad-spectrum antibacterials. Two novel 6-desfluoroquinolone derivatives (6-DFQs), HM-12 and HM-13, were evaluated for their anti-HIV activity in acutely, chronically and latently HIV-1-infected cell cultures (including M/M) and found to behave as potent HIV-1 transcription inhibitors. Interestingly, in a murine in vivo model in which mice are inoculated with latently HIV-1-infected human cells, 6-DFQs were shown to efficiently prevent virus activation upon TNFα triggering. Thus, these compounds are able to slow down virus replication, and should be interesting candidate drugs to be combined with entry, integrase or reverse transcriptase inhibitors that acts prior to the proviral integration in the treatment of HIV-1 infections.
Because it is known that HIV-1 infection induces a significant perturbation of the oxidative status of M/M, it can be interesting also to study new drugs able to counteract the cell damage correlated with this oxidative condition. In particular, we studied MnTBAP (Mn(III)tetrakis(4-benzoic acid)porphrin chloride), a synthetic peroxynitrite decomposition catalyst, able to reduce oxidative stress subsequent to peroxynitrite generation in HIV-1-infected M/M and found the compound efficient in inhibiting HIV-1 replication in M/M. In summary, the inherent properties of HIV-1 infection of M/M should be taken into account to design therapeutic strategies aimed at achieving an optimal therapeutic effect in all tissue compartments where the virus hides and replicates. We have investigated four possible new drug classes of compounds that represent interesting candidate drug leads for further (pre)clinical studies
Leptusa (Drepanoleptusa) pollicita ASSING 2010
No full textLeptusa (Drepanoleptusa) pollicita ASSING, 2010 Material examined: China: 1 , Yunnan, Lincang Pref., Xue Shan, 11 km ENE Lincang, 23°55'N, 100°11'E, 2510 m, secondary pine forest with rhododendron, sifted, 10.IX.2009, leg. Schülke (MNB). This species was described based on type material collected in Xue Shan and Laobie Shan, North Yunnan.Published as part of Assing, Volker, 2021, New species and additional records of Leptusa from the Palaearctic region, with a focus on the faunas of China and the Caucasus region (Coleoptera: Staphylinidae: Aleocharinae), pp. 103-126 in Beiträge Zur Entomologie = Contributions to Entomology 71 (1) on page 118, DOI: 10.21248/contrib.entomol.71.1.103-126, http://zenodo.org/record/574306
Mechanisms underlying activity of antiretroviral drugs in HIV-1-infected macrophages: new therapeutic strategies
No full textMonocyte-derived macrophages (M/M)
are considered the second cellular target of HIV-1
and a crucial virus reservoir. M/M are widely distributed
in all tissues and organs, including the
CNS, where they represent the most common HIVinfected
cells. Differently from activated CD4 T
lymphocytes, M/M are resistant to the cytopathic
effect of HIV and survive HIV infection for a long
time. Moreover, HIV-1 replication in M/M is a key
pathogenetic event during the course of HIV-1 infection.
Overall findings strongly support the clinical
relevance of anti-HIV drugs in M/M. Nucleoside
RT inhibitors (NRTIs) are more active against
HIV in M/M than in CD4 T lymphocytes. Their
activity is further boosted by the presence of an
additional monophosphate group (i.e., a phosphonate
group, as in the case of Tenofovir), thus overcoming
the bottleneck of the low phosphorylation
ability of M/M. In contrast, the antiviral activity of
non-NRTIs (not affecting the DNA chain elongation)
in M/M is similar to that in CD4 T lymphocytes.
Protease inhibitors are the only clinically
approved drugs acting at a late stage of the HIV
lifecycle. They are able to interfere with HIV replication
in HIV-1 chronically infected M/M, even if
at concentrations greater than those observed in
HIV-1 chronically infected CD4 T lymphocytes.
Finally, several new drugs have been shown to interfere
efficiently with HIV replication in M/M, including
entry inhibitors. A better understanding of
the activity of the anti-HIV drugs in M/M may represent
a key element for the design of effective
anti-HIV chemotherapy
Therapeutic strategies towards HIV-1 infection in macrophages
No full textIt is widely recognized that macrophages (M/M) represent a crucial target of HIV-1 in the body and play a pivotal role in the pathogenic progression of HIV-1 infection. This strongly supports the clinical relevance of therapeutic strategies able to interfere with HIV-1 replication in M/M. In vitro studies showed that nucleoside analogue inhibitors of HIV-1 reverse transcriptase have potent antiviral activity in M/M, although the limited penetration of these compounds in sequestered body compartments and low phosphorylation ability of M/M, suggest that a phosphonate group linked to NRTIs may confer greater anti-HIV-1 activity in M/M. Differently, the antiviral activity of non-nucleoside reverse transcriptase inhibitors in M/M is similar to that found in CD4+ lymphocytes. Interestingly, protease inhibitors, acting at a post-integrational stage of HIV-1 life-cycle are the only drugs active in chronically infected M/M. A careful analysis of the distribution of antiviral drugs, and the assessment of their activity in M/M, represent key factors in the development of therapeutic strategies aimed to the treatment of HIV-1-infected patients. Moreover, testing new and promising antiviral compounds in such cells may provide crucial hints about their efficacy in patients infected by HIV. © 2006 Elsevier B.V. All rights reserved
The contribution of peroxynitrite generation in HIV replication in human primary macrophages
No full textBackground: Monocytes/Macrophages (M/M) play a pivotal role as a source of virus during the
whole course of HIV-1 infection. Enhanced oxidative stress is involved in the pathogenesis of HIV-
1 infection. HIV-1 regulatory proteins induce a reduction of the expression and the activity of
MnSOD, the mitochondrial isoform leading to a sustained generation of superoxide anions and
peroxynitrite that represent important mediators of HIV-1 replication in M/M. MnTBAP
(Mn(III)tetrakis(4-benzoic acid)porphrin chloride), a synthetic peroxynitrite decomposition
catalyst, reduced oxidative stress subsequent to peroxynitrite generation.
Results: Virus production was assessed by p24 ELISA, western blot, and electron microscopy
during treatment with MnTBAP. MnTBAP treatment showed a reduction of HIV-1 replication in
both acutely and chronically infected M/M: 99% and 90% inhibition of p24 released in supernatants
compared to controls, respectively. Maturation of p55 and p24 was strongly inhibited by MnTBAP
in both acutely and chronically infected M/M. EC50 and EC90 are 3.7 (± 0.05) μM and 19.5 (± 0.5)
μM, in acutely infected M/M; 6.3 (± 0.003) μM and 30 (± 0.6) μM, in chronically infected M/M. In
acutely infected peripheral blood limphocytes (PBL), EC50 and EC90 are 7.4 (± 0.06) μM and of 21.3
(± 0.6) μM, respectively. Treatment of acutely-infected M/M with MnTBAP inhibited the elevated
levels of malonildialdehyde (MDA) together with the nitrotyrosine staining observed during HIV-1
replication. MnTBAP strongly reduced HIV-1 particles in infected M/M, as shown by electron
microscopy. Moreover, in presence of MnTBAP, HIV-1 infectivity was reduced of about 1 log
compared to control.
Conclusion: Results support the role of superoxide anions in HIV-1 replication in M/M and
suggest that MnTBAP may counteract HIV-1 replication in combination with other antiretroviral
treatments
Oxidative stress and HIV infection: Target pathways for novel therapies?
No full textOxidative stress is thought to play an important role in the progression of HIV infection. In fact, it has been observed that perturbations in antioxidant defense systems, and consequently redox imbalance, are present in many tissues of HIV-infected patients. Moreover, there is clear evidence that oxidative stress may contribute to several aspects of HIV disease, including viral replication, inflammatory response and decreased immune cell proliferation. For this reason, the exogenous supply of antioxidants, as natural compounds and new-generation antioxidants that scavenge free radicals, might represent an important additional strategy for the treatment of HIV infection in the era after HAART therapy has been applied. © 2008 Future Medicine Ltd
Profound anti-HIV-1 activity of DAPTA in monocytes/macrophages and inhibition of CCR5-mediated apoptosis in neuronal cells
No full textMonocytes/macrophages (M/M) are strategic reservoirs of HIV-1, spreading the virus to other cells and inducing apoptosis in T-lymphocytes, astrocytes and neurons. M/M are commonly infected by R5 HIV-1 strains, which use the chemokine receptor CCR5. D-Ala-peptide T-amide (DAPTA), or Peptide T, named for its high threonine content (ASTTTNYT), is a synthetic peptide comprised of eight amino acids (185-192) of the gp120 V2 region and functions as a viral entry inhibitor by targeting selectively CCR5. The anti-HIV-1 activity of DAPTA was evaluated in M/M infected with R5 HIV-1 strains. DAPTA at 10-9M inhibited HIV-1 replication in M/M by >90%. PCR analysis of viral cDNA in M/M showed that DAPTA blocks HIV entry and in this way prevents HIV-1 infection. Moreover, DAPTA acts as a strong inhibitor and was more active than the non-peptidic CCR5 antagonist TAK-779 in inhibiting apoptosis (mediated by R5 HIV-1 strains produced and released by infected M/M) on a neuroblastoma cell line. Our results suggest that antiviral compounds which interfere with receptor mechanisms such as CCR5 could be important, either alone or in combination with other antiretroviral treatments, in preventing HIV infection in the central nervous system and the consequential neuronal damage that leads to neuronal AIDS. ©2007 International Medical Press
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