HIV-induced Cytopathic Effects Research Articles

Toward the unveiling of HIV-1 dynamics: Involvement of monocytes/macrophages in HIV-1 infection

HIV-1 targets the monocyte/macrophage lineage and CD4+ T cells for its replication. The efficiency of infection, replication, and cell-to-cell spread differs between these cell types. These differences are caused by various factors such as viral tropism, viral proteins, host factors, and cell proliferation. However, the precise mechanisms of how macrophages influence HIV-1 infection have not been fully elucidated. Macrophages are long-lived cells susceptible to infection predominantly with R5-tropic strains of HIV-1. Although co-receptor use switches from CCR5 to CXCR4 in up to 50% of patients during AIDS progression, R5-tropic strains remain predominant in the remaining patients. Compared to HIV-1-infected T cells, infected macrophages are less susceptible to HIV-induced cytopathic effects and survive for more than a few weeks. Efforts to cure HIV-1 may be thwarted by the existence of reservoir cells that cannot be targeted by ART. Resting CD4+ T lymphocytes are thought to be the primary reservoir cells, but recent studies demonstrated that monocyte/macrophage lineage cells may also act as viral reservoirs. This review will focus on the impact of monocytes/macrophages during HIV-1 replication, the establishment of the reservoirs, and recent approaches toward HIV-1 eradication by specifically targeting monocyte/macrophage lineage cells.

The HIV Reservoir in Monocytes and Macrophages.

In people living with HIV (PLWH) who are failing or unable to access combination antiretroviral therapy (cART), monocytes and macrophages are important drivers of pathogenesis and progression to AIDS. The relevance of the monocyte/macrophage reservoir in PLWH receiving cART is debatable as in vivo evidence for infected cells is limited and suggests the reservoir is small. Macrophages were assumed to have a moderate life span and lack self-renewing potential, but recent discoveries challenge this dogma and suggest a potentially important role of these cells as long-lived HIV reservoirs. This, combined with new HIV infection animal models, has led to a resurgence of interest in monocyte/macrophage reservoirs. Infection of non-human primates with myeloid-tropic SIV implicates monocyte/macrophage activation and infection in the brain with neurocognitive disorders, and infection of myeloid-only humanized mouse models are consistent with the potential of the monocyte/macrophage reservoir to sustain infection and be a source of rebound viremia following cART cessation. An increased resistance to HIV-induced cytopathic effects and a reduced susceptibility to some antiretroviral drugs implies macrophages may be relevant to residual replication under cART and to rebound viremia. With a reappraisal of monocyte circulation dynamics, and the development of techniques to differentiate between self-renewing tissue-resident, and monocyte-derived macrophages in different tissues, a new framework exists to contextualize and evaluate the significance and relevance of the monocyte/macrophage HIV reservoir. In this review, we discuss recent developments in monocyte and macrophage biology and appraise current and emerging techniques to quantify the reservoir. We discuss how this knowledge influences our evaluation of the myeloid HIV reservoir, the implications for HIV pathogenesis in both viremic and virologically-suppressed PLWH and the need to address the myeloid reservoir in future treatment and cure strategies.

Bioengineered intravaginal isolate of Lactobacillus plantarum expresses algal lectin scytovirin demonstrating anti-HIV-1 activity

Efforts to develop preventatives against HIV infection through sexual route have identified, among many, algal lectins as the potent molecules for scaffolding HIV entry inhibition. Algal lectin scytovirin (SVN) from Scytonema varium, a cyanobacterium, has anti-HIV effects with the potential for use in sculpting HIV neutralization. We created a recombinant strain of human vaginal L. plantarum for extracellular expression of recombinant (r)SVN. The rSVN protein containing culture supernatant was analyzed for its binding with HIV-1 gp160, and for inhibiting infection with primary R5 and X4 HIV-1 strains in TZM-bl cells. The rSVN protein extant in recombinant L. plantarum culture supernatant binds to HIV-1 gp160 and reduces the HIV-induced cytopathic effect to nearly 56.67% and 86.47% in R5 and X4 HIV-1 infected TZM-bl cells, respectively. The fortified L. plantarum may be explored for its use as a live virucide in vaginal mucosa of high risk women to prevent HIV entry.

Anti-HIV activities of novel synthetic peptide conjugated chitosan oligomers

Chitosan and chitosan derived compounds are marine byproducts which have been shown to exhibit bioactivities including antibacterial, antioxidant, antidiabetic and anti-HIV. Proteins are among the most potent and selective molecules offering an endless potential of different structure and sequence preferences. The tripeptides which consist of tryptophan (W), methionine (M) and glutamine (Q) have been conjugated with chitosan oligomers. Among them QMW-COS and WMQ-COS protected C8166 cells from cell-lytic effects of HIV-1RF strain. Furthermore, these two compounds inhibited HIV-induced syncytia formation. We confirmed the decrease in viral-load in cell culture using p24 ELISA assay. To determine the specific mode of action of QMW-COS and WMQ-COS to inhibit HIV, we checked the inhibitory action of these compounds on viral reverse transcriptase and protease enzymes. However, we could not detect any inhibitory activity of conjugated compounds on recombinant reverse transcriptase and protease enzyme in vitro. When we co-cultured HIV-infected and uninfected C8166 cells, these two compounds actively inhibited the syncytia formation upon co-culture assay. Time-dependent addition of compounds and finally gp120-CD4 ELISA assay revealed that QMW-COS and WMQ-COS are bioactive compounds inhibiting HIV-induced cytopathic effects via exerting their effects on HIV entry stage.

Anti-HIV activities of extracts from Pu-erh tea

AimTo evaluate the anti-HIV activities of extracts from two commonly forms of Pu-erh tea (fermented), green tea-like (unfermented). MethodsThe cytotoxicities of extracts on C8166, MT4 and PBMC were assessed by MTT and the anti-HIV activities of extracts were evaluated by syncytium reduction and p24 antigen assay. ResultsAll extracts had low cytotoxicities with the CC50 from 120.63 to 524.95 μg·mL−1. All extracts can inhibit HIV-induced cytopathic effects, with EC50 various from 11.13 to 67.49 μg·mL−1. The WEPT's were better than EEPTs, moreover the FPT's water extracts were better than the GTLPT's especially YYP-31 with SI value 42.40. YYP-31 also inhibited HIV-1RF and HIV-2CBL-20 infection with EC50 of 30.82 and 39.79 μg·mL−1, respectively. YYP-31 reduced p24 antigen expression in HIV-1IIIB acute infected C8166 and in HIV-1KM018 infected PBMC with EC50 values of 14.95 and 74.63 μg·mL−1, respectively. YYP-31 blocked the fusion between normal C8166 cells and HIV-1 chronically infected H9 cells with EC50 values of 234.27 μg·mL−1. It exhibits markedly synergistic anti-HIV activity in combination with AZT but can't inhibit activities of reverse transcriptase. ConclusionPu-erh tea extracts exhibit highly efficient anti-HIV-1 activity and can be considered to be used to as a complementary therapy or a health product to HIV patients.

TLR-9 agonist protects human monocytic cells against HIV-Vpr-induced apoptosis: a critical role for Calmodulin-dependent protein kinase-II, c-JUN N terminal kinase and anti-apoptotic c-IAP-2 gene (154.11)

Abstract Monocytic cells unlike CD4+ T cells survive HIV induced apoptosis and serve as key viral reservoirs. Mechanisms underlying the development of resistance to HIV-induced cytopathic effects are poorly understood. In chronic HIV infections, microbial products translocate from the gut and may activate lymphocytes conferring anti-apoptotic signals. By using Vpr52-96 peptide, an accessory protein of HIV known to cause apoptosis in various cell types, as a model for apoptosis-inducing protein, we demonstrate that Vpr52-96 induced apoptosis in primary monocytes and undifferentiated THP-1 cells. However, monocyte-derived macrophages and PMA-differentiated THP-1 cells exhibited profound resistance to Vpr-induced apoptosis. Interestingly, prior treatment of primary monocytes and undifferentiated THP-1 cells with TLR-9 agonist, CpG, induced resistance to Vpr-mediated apoptosis. This resistance was found to be mediated by extracellular calcium influx, activation of c-Jun N terminal kinase via Calmodulin-dependent kinase II and induction of anti apoptotic cIAP2 gene. Our results also revealed a novel pathway by which Vpr may dysregulate TLR signaling in monocytes by targeting MyD88. Interestingly, CpG protected these cells by blocking the Vpr-induced inhibition of MyD88. Overall, our results suggest that anti-apoptotic cIAP2 gene and calcium activated JNK signaling play a crucial role in conferring resistance induced by CpG against Vpr-mediated apoptosis in monocytic cells.

A Decontamination and Sterilization Protocol Employed During Reuse of Cardiac Electrophysiology Catheters Inactivates Human Immunodeficiency Virus

To assess the effect of a standard decontamination and sterilization protocol employed during reuse of cardiac electrophysiology (EP) catheters on human immunodeficiency virus (HIV). Public health viral research laboratory. Studies were performed on distal, electrode-containing segments of 40 EP catheters previously used in up to 10 clinical EP procedures. EP catheter segments were immersed for 1 hour in blood contaminated with a high titer of HIV. After air drying for 2 hours, subgroups of 8 EP catheters were subjected to either (1) no treatment, (2) washing in general purpose detergent, (3) washing in enzyme cleaner, (4) sterilization in ethylene oxide, or (5) the full protocol of sequential detergent-enzyme cleaner-ethylene oxide exposure. HIV infectivity after treatment was determined by measuring HIV RNA and, in cell culture studies, assessing HIV-induced cytopathic effects (CPEs) and supernatant HIV-specific p24 antigen content With no treatment, all catheters had high HIV RNA levels associated with CPEs and high p24 antigen levels. After washing in detergent, 5 of 8 catheters had HIV RNA detected, but without CPEs or p24 antigen. HIV RNA was detected in all catheters after washing in enzyme cleaner, with CPEs and a high p24 antigen level in 1 of 8 catheters. HIV RNA, CPEs, and p24 antigen were absent after ethylene oxide. After the full protocol, HIV RNA levels were undetectable (n = 7) or low (n = 1), without evidence of CPEs or p24 antigen. Appropriate decontamination and sterilization of EP catheters during reuse is highly effective in inactivating HIV.

Inhibitory effects of triterpene-azidothymidine conjugates on proliferation of human immunodeficiency virus type 1 and its protease.

The conjugates of some dicarboxylic acid hemiesters of triterpenes which show potent inhibition against human immunodeficiency virus type 1 protease (HIV-1 PR) with a reverse transcriptase inhibitor azidothymidine (AZT) or anti-HIV alkaloid FK 3000 were prepared, and their inhibitory activities were investigated against HIV-induced cytopathic effects (CPE) and HIV-1 PR. Most of the triterpene-AZT conjugates showed potent anti-HIV activity as well as moderate to potent PR inhibitory activity, though AZT itself showed no PR inhibitory activity at all. However, the triterpene-FK 3000 conjugates showed neither PR inhibitory activity nor anti-HIV activity.

Anti-Human Immunodeficiency Virus Activity of YK-FH312 (a Betulinic Acid Derivative), a Novel Compound Blocking Viral Maturation

Betulinic acid, a triterpenoid isolated from the methyl alcohol extract of the leaves of Syzigium claviflorum, was found to have a potent inhibitory activity against human immunodeficiency virus type 1 (HIV-1). Betulinic acid derivatives were synthesized to enhance the anti-HIV activity. Among the derivatives, 3-O-(3',3'-dimethylsuccinyl) betulinic acid, designated YK-FH312, showed the highest activity against HIV-induced cytopathic effects in HIV-1-infected MT-4 cells. To determine the step(s) of HIV replication affected by YK-FH312, a syncytium formation inhibition assay in MOLT-4/HIV-1(IIIB) and MOLT-4 coculture, a multinuclear-activation-of-galactosidase-indicator (MAGI) assay in MAGI-CCR5 cells, electron microscopic observation, and a time-of-addition assay were performed. In the syncytium formation inhibition assay or in the MAGI assay for de novo infection, the compound did not show inhibitory effects against HIV replication. Conversely, no virions were detected in HIV-1-infected cell cultures treated with YK-FH312 either by electron microscopic observation or by viral yield in the supernatant. In accordance with a p24 enzyme-linked immunosorbent assay of culture supernatant in the time-of-addition assay, YK-FH312 inhibited virus expression in the supernatant when it was added 18 h postinfection. However, Western blot analysis of the cells in the time-of-addition assay revealed that the production of viral proteins in the cells was not inhibited completely by YK-FH312. These results suggest that YK-FH312 might affect the step(s) of virion assembly and/or budding of virions, and this is a novel mechanism of action of an anti-HIV compound.

Synthesis and anti-HIV activity of nonatyrosine N- and O1–9-decasulfate

To develop a potent and effective anti-HIV compound with a definite polyanionic structure, synthesis of oligotyrosine sulfates by oligomerization with simultaneous sulfation of tyrosine was tried. One component was successfully isolated from the mixture containing many products as its sodium salt (Y-ART-4) and was identified as the salt of nonatyrosine N- and O1–9-decasulfate, NaO3S–[Tyr(SO3Na)]9–ONa. Anti-HIV activity of Y-ART-4, determined from the protection it provided against HIV-induced cytopathic effects, was almost the same with that of dextran sulfate and curdlan sulfate.

Anti-HIV-1 phorbol esters from the seeds of Croton tiglium

Five phorbol diesters, together with three known ones, were isolated from a MeOH extract of the seeds of Croton tiglium, and their structures were determined by spectroscopic methods and selective hydrolysis of acyl groups. These compounds were assessed for their abilities to inhibit an HIV-induced cytopathic effect (CPE) on MT-4 cells and to activate protein kinase C (PKC) associated with tumor-promoting action. 12- O-Acetylphorbol-13-decanoate and 12- O-decanoylphorbol-13-(2-methylbutyrate) effectively inhibited the cytopathic effect of HIV-1 [complete inhibitory concentration (IC 100) values of 7.6 ng/ml and 7.81 μg/ml, and minimum cytotoxic concentration (CC 0) value of 62.5 and 31.3 μg/ml, respectively]; however, 12- O-acetylphorbol-13-decanoate showed no activation of PKC at concentrations of 10 and 100 ng/ml. 12- O-Tetradecanoylphorbol-13-acetate (TPA) was found to be not only the most potent inhibitor of HIV-1-induced CPE (IC 100 value of 0.48 ng/ml), but also the most potent activator of PKC (100% activation at 10 ng/ml).

Inhibitory effects of Sudanese plant extracts on HIV-1 replication and HIV-1 protease.

Forty-eight methanol and aqueous extracts from Sudanese plants were screened for their inhibitory activity on viral replication. Nineteen extracts showed inhibitory effects on HIV-induced cytopathic effects (CPE) on MT-4 cells. The extracts were further screened against HIV-1 protease (PR) using an HPLC assay method. Of the tested extracts, the methanol extracts of Acacia nilotica (bark and pods), Euphorbia granulata (leaves), Maytenus senegalensis (stem-bark) and aqueous extracts of A. nilotica (pods) and M. senegalensis (stem-bark) showed considerable inhibitory effects against HIV-1 PR. Inhibitory principles were isolated from M. senegalensis and their activities were also discussed.

A search for anti-viral properties in Panamanian medicinal plants.: The effects on HIV and its essential enzymes

Aqueous and methanolic extracts of 39 Panamanian medicinal plants were tested for anti-human immunodeficiency virus (HIV) effects. The extracts were tested for the inhibition of HIV-induced cytopathic effects in cultured cells, HIV-reverse transcriptase (RT) and HIV-protease (PR) enzymes. The water extract of the branches of Jatropha curcas (Euphorbiaceae) inhibited strongly the HIV-induced cytopathic effects with low cytotoxicity. On the other hand, the water extracts of the whole plant of Chamaesyce hyssopifolia (Euphorbiaceae), the leaves of Cordia spinescens (Boraginaceae) and the aerial parts of Hyptis lantanifolia (Labiatae), and the methanol extract of the aerial parts of Tetrapteris macrocarpa (Malpighiaceae) were potent inhibitors of HIV-RT (IC 50: 6–8 μg/ml). Seven out of 39 plants were found to be moderate inhibitors of HIV-PR (IC 50: 43–100 μg/ml). Furthermore, we report on the respective inhibitory substances of J. curcas, C. hyssopifolia and C. spinescens, and their possible mechanism of action.

Inhibition of cytopathic effect of human immunodeficiency virus-1 by water-soluble extract ofGanoderma lucidum

To examine components ofGanoderma lucidum for anti-human immunodeficiency virus (HIV) activity, the aqueous extracts of its basidiocarps were separated into high-molecular-weight (HMF) and low-molecular-weight (LMF) fractions. These fractions were used in XTT [2,3-bis (2-methoxy-4-nitro-5-sulfophenyl)-5-[(phenylamino) carbonyl]-2H-tetrazolium hydroxide] antiviral assay which can quantitatively measure cytopathic effects of HIV-1 on CEM, human T lymphoblastoid cell line. The CEM cell line added with serial diluted HMF or LMF was cultured in the absence or presence of HIV-1. The results showed that the LMF of the aqueous extract strongly inhibited cytopathic effect of the target cell induced by HIV-1. When two-fold serially diluted LMF ranging from 0.97 mug/ml to 125.00 mug/ml was added to the virus-free culture system, no toxicity on the target cells was detected in all the concentrations tested. However, when it was added to the HIV-infected culture system, the viabilities of the target cell reached a plateau recovering its viabilities to 71.7% and 82.5% in experiment-1 and-2 at 15.60 mug/ml, respectively. The cell viabilities were then gradually decreased but maintained at more than 50% above 31.20 mug/ml concentration. On the contrary, HMF did not prevent any HIV-induced cytopathic effect at any concentrations tested on this cell line. From these results, negligible toxicities were observed by both HMF and LMF ofG. lucidum, and recovery of cell viability in HIV infected target cell was induced only by LMF of the carpophores.

Anti-HIV Activities of Anionic Metalloporphyrins and Related Compounds

Various water-soluble polysulphonated and polycarboxylated porphyrins and some of their metallated derivatives have been prepared and their antiviral properties against human immunodeficiency virus (HIV-1, HIV-2), simian immunodeficiency virus and other viruses are reported. Besides these polyanionic compounds, two new series of porphyrins were included and studied from the perspective of bio-availability modulation: (i) acefylsulphonamido derivatives endowed with weak acidity properties (deprotonation gives the corresponding anionic derivatives in a pH range 4.5-8.5) and (ii) compounds with the anionic charge transiently masked by esterification (acetoxymethyl- and pivaloyloxymethylesters). Among the more active compounds in inhibiting HIV-induced cytopathic effects, the sulphonated and carboxylated porphyrin complexes were found to interact directly with the HIV protein gp 120 and not with the CD4 cellular receptor.

Reduction of Human Immunodeficiency Virus Production and Cytopathic Effects by Inhibitors of the Na+/K+/2Cl−Cotransporter

Infection of CD4+T-lymphoblastoid cells by cytopathic strains of HIV-1 results in an increase in cell volume that leads to lysis and cell death. The increase in volume is attributable in part to an HIV-induced increase in intracellular monovalent ion concentrations mediated by the plasma membrane-associated Na+/K+/2 Cl−cotransporter. Loop diuretics, which inhibit cotransporter activity, blocked HIV-induced HIV production and cytopathic effects at physiologically employed concentrations.

Interferon-gamma-induced downregulation of CD4 inhibits the entry of human immunodeficiency virus type-1 in primary monocytes.

We have previously shown that the treatment of monocytes with interferon-gamma (IFN-gamma) prior to exposure with human immunodeficiency virus type-1 (HIV) results in complete inhibition of HIV infection of monocytes. In the present report, we have extended this study to obtain information on the mechanism(s) underlying IFN-gamma-induced inhibition of HIV infection of monocytes. To examine the effect of IFN-gamma on HIV entry, the first event in the infectious cycle of the virus, we amplified HIV-gag sequences in the genomic DNA and RNA of IFN-gamma treated monocytes, and found no evidence for the presence of either proviral DNA or HIV RNA sequences. These results were consistent with the absence of intracellular HIV particles either in the latent or actively replicating state as determined by flow-cytometric analysis of these cells. Furthermore, no HIV-induced cytopathic effects, such as multinucleated giant cell formation or cell death, were observed in IFN-gamma-treated monocytes after their exposure to HIV. Stimulation of IFN-gamma-treated monocytes 6 days postinfection with tumor necrosis factor-alpha (TNF-alpha), which is known to augment HIV replication in the infected cells, did not result in the induction of the HIV indicating the absence of latent HIV infection in IFN-gamma-treated monocytes. Treatment of monocytes with IFN-gamma, TNF-alpha, or with a combination of the two agents which is known to induce antimicrobial free radical nitric oxide (NO2- in the murine system did not induce NO2- production human monocytes suggesting the antiviral activity of IFN-gamma to be independent of NO2(-)-mediated killing of HIV or HIV-infected monocytes.(ABSTRACT TRUNCATED AT 250 WORDS)

A strong inhibition of HIV-induced cytopathic effects by synthetic (1→6)-α- d-mannopyranan sulfate

The anti-HIV effects of mannopyranan sulfate ( 1) were investigated by using MT-4 cells, namely, an HTLV-I-carrying CD-4 positive cell-line, in vitro. Stereoregular (1→6)-α- d-mannopyranan, which had been synthesized by ring-opening polymerization of a 1,6-anhydromannose derivative, was sulfated with piperidine- N-sulfonic acid to provide 1. N.m.r. analysis of 1 indicated that the reactivity of hydroxyl groups was in the order, 3-OH > 2-OH > > 4-OH. Mannopyranan sulfate having degree of substitution (d.s.) of 1.19–1.83 effectively inhibited HIV-induced cytopathic effects at a concentration of >3.3 μg/mL. The anticoagulant activity and the adsorption on concanavalin A of 1 indicated the possibility of selective binding of 1 having d.s. of 1.19–1.83 to HIV-protein.

Enhanced HIV replication in macrophage colony-stimulating factor-treated monocytes.

Monocytes cultured 7 to 10 days in recombinant human macrophage CSF (MCSF) were greater than 400-fold more susceptible to HIV infection than an equal number of cells cultured in medium alone. Levels of reverse transcriptase activity and p24 Ag in culture fluids of monocytes treated with MCSF 1 wk before and continuously after HIV infection were significantly greater than those of control cells cultured without MCSF. HIV-induced cytopathic effects in the MCSF-treated cultures also increased in both frequency and extent. At any given viral inoculum, the frequency of HIV-infected cells, the level of HIV mRNA/infected cell, and the level of proviral DNA/infected culture in MCSF-treated monocyte cultures were dramatically greater than those in control cultures. These differences were directly related to MCSF concentration to a maximum between 750 and 1000 U/ml MCSF, and were evident at all time points examined through 5 wk. None of the preceding effects was observed when MCSF was added at the time of or 1 wk after HIV infection. These data suggest that the predominant effect of MCSF for control of HIV infection is on the monocyte itself, not the virus. If these in vitro observations extend to the HIV-infected patient, then the variable levels of MCSF in tissue or blood may determine both the susceptibility of macrophages to virus infection and the extent of virus replication in infected cells.

Selective antiviral activity of synthetic soluble l-tyrosine and l-dopa melanins against human immunodeficiency virus in vitro

Melanins are pigments found in hair, skin, irides of the eye, and brain. Their functions in mammals include protection from exposure to sunlight, camouflage from predators, sexual recognition within species, and possible electron transfer reactants. Most natural melanins exist in an insoluble form, which is one reason there is little information on the biological properties of soluble melanins. Here, synthetic soluble melanins were obtained by chemical oxidation of l-tyrosine or spontaneous oxidation of l-β-3,4-dihydroxyphenylalanine ( l-dopa). Replication of human immunodeficiency virus types 1 and 2 (HIV-1 and HIV-2) was inhibited by soluble melanin in two human lymphoblastoid cell lines (MT-2 and H9) and in phytohemagglutinin-stimulated human T cells. Effective concentrations of 0.15-10 μg/ml had no cell toxicity. Melanin blocked infection by cell-free virus and interfered with HIV-induced syncytium formation and cytopathic effects when fusion-susceptible, uninfected cells, were mixed with chronically infected cells. Melanin also impeded the HIV-1 envelope surface glycoprotein, and T cell specific monoclonal antibody leu-3a (CD4), but not leu-5b (CD2), from binding to the surface of MT-2 cells. No effect on HIV-1 reverse transcriptase activity in viral lysates was observed. These results identify a unique biological property of melanin, and suggest that soluble melanins may represent a new class of pharmacologically active substances which should be further investigated for potential therapeutic utility in the treatment of Acquired immune Deficiency Syndrome (AIDS).