M.G. Santoro

Inhibition of HIV-1 replication by cyclopentenone prostaglandins in acutely infected human cells. Evidence for a transcriptional block.

Cyclopentenone prostaglandins (PGs) inhibit virus replication in several DNA and RNA virus models, in vitro and in vivo. In the present report we demonstrate that the cyclopentenone prostaglandins PGA(1) and PGJ(2) at nontoxic concentrations can dramatically suppress HIV-1 replication during acute infection in CEM-SS cells. PGs did not affect HIV-1 adsorption, penetration, reverse transcriptase activity nor viral DNA accumulation in HIV-1 infected cells. A dramatic reduction in HIV-1 mRNA levels was detected up to 48-72 h after infection (p.i.) in PG-treated cells, and HIV-1 protein synthesis was greatly reduced by a single PG-treatment up to 96 h p.i. Repeated PGA(1)-treatments were effective in protecting CEM-SS cells by the cytopathic effect of the virus, and in dramatically reducing HIV-1 RNA levels up to 7 d after infection. The antiviral effect was not mediated by alterations in the expression of alpha-, beta-, or gamma-interferon,TNFalpha, TNFbeta, IL6, and IL10 in HIV-infected CEM-SS cells. The fact that prostaglandins are used clinically in the treatment of several diseases, suggests a potential use of cyclopentenone PGs in the treatment of HIV-infection.

Inhibition of virus protein glycosylation as the mechanism of the antiviral action of prostaglandin A in Sendai virus-infected cells.

Prostaglandin A (PGA) inhibits Sendai virus replication at doses non-toxic to uninfected cells. In this report, the antiviral action of PGA was found to be associated with specific alterations of viral protein synthesis. SDS-PAGE analysis of [35S]methionine-labelled proteins showed that while the non-glycosylated viral polypeptides (P, NP and M) were normally synthesized in PGA1-treated cells, the viral glycoproteins HN and F0 were not detected. Two new polypeptides of Mr respectively 4000 and 1000 lower than the HN and F0 proteins were instead detected. The results suggest that these new polypeptides are defectively glycosylated forms of HN and F0. In fact PGA1 was found selectively to inhibit glucosamine incorporation into Sendai virus-infected cells, but not in uninfected cells. Moreover, in infected cells the inhibition of glucosamine incorporation appeared to be selective towards viral polypeptides. This effect was not due to a decreased uptake of glucosamine from the cells after PGA1 treatment. The results also show that the PGA1-induced alteration of the HN protein caused a loss of its biological function and prevented the insertion of this protein into the cell membrane, thereby blocking virus maturation. Finally, a polypeptide of Mr 74K, the synthesis of which was induced by PGA1, appeared to be a possible mediator of PGA1 antiviral action.

Inhibition of Sindbis virus replication by cyclopentenone prostaglandins: a cell-mediated event associated with heat-shock protein synthesis.

Cyclopentenone prostaglandins (PGs) have been shown to inhibit the replication of several DNA and RNA viruses. Here we report on the effect of prostaglandin A1 (PGA1) on the multiplication of a positive strand RNA virus, Sindbis virus, in Vero cells under one-step multiplication conditions. PGA1 was found to inhibit Sindbis virus production dose-dependently, and virus yield was reduced by more than 90% at the concentration of 8 micrograms/ml, which was non-toxic to the cells and did not inhibit DNA, RNA or protein synthesis in Vero cells. The cyclopentenone prostaglandin delta 12-PGJ2 was also shown to be a potent inhibitor of Sindbis virus replication. Virus-induced reduction of [3H]uridine uptake by cells was partially prevented by PGA1 treatment, which also caused a 1 h delay in the peak of virus RNA synthesis. SDS-PAGE analysis of [35S]methionine-labeled proteins showed that PGA1 moderately inhibited the synthesis of the viral structural proteins E1, E2 and C, and induced the synthesis of a 72 kDa M(r) protein, identified as a heat-shock protein related to the HSP70 group, in both virus-infected and uninfected cells. Actinomycin D treatment completely prevented PGA1-antiviral activity, indicating that a cellular product is responsible for this action. PGA1-induced HSP70 is a good candidate for this role.

Δ12-Prostaglandin J2 Is a Potent Inhibitor of Influenza A Virus Replication

ABSTRACT 9-Deoxy-Δ9,Δ12-13,14-dihydro-prostaglandin D2 (Δ12-PGJ2), a natural cyclopentenone metabolite of prostaglandin D2, is shown to possess therapeutic efficacy against influenza A virus A/PR8/34 (H1N1) infection in vitro and in vivo. The results indicate that the antiviral activity is associated with induction of cytoprotective heat shock proteins and suggest novel strategies for treatment of influenza virus infection.

Inhibition of vesicular stomatitis virus replication by Δ12-prostaglandin J2 is regulated at two separate levels and is associated with induction of stress protein synthesis

delta 12-Prostaglandin J2 (delta 12-PGJ2), a naturally occurring dehydration product of prostaglandin D2, is shown to suppress the replication of vesicular stomatitis virus (VSV) in two different epithelial monkey cell lines. A significant delay in the virus-induced cytopathic effect and a dramatic inhibition of virus production can be obtained at doses which do not inhibit protein synthesis in uninfected cells, and induce the synthesis of heat shock proteins (HSPs) in both uninfected and VSV-infected cells. delta 12-PGJ2 is shown to block VSV replication at two separate levels in the early and late phase of the virus replication cycle. Treatment started soon after VSV infection greatly suppresses viral (but not cellular) protein synthesis and prevents the virus-induced shut-off of host cell protein synthesis. This effect is accompanied by the induction of HSP synthesis. delta 12-PGJ2-treatment in a late phase of the virus replication cycle, when all virus proteins have been synthesized, still causes a dramatic block of infectious virus production. This block is accompanied by a decrease in [3H]glucosamine incorporation into the virus glycoprotein G, at concentrations which do not alter glucosamine uptake by the cells, suggesting that a defect in virus protein glycosylation could be responsible for the antiviral activity. Finally, delta 12-PGJ2 causes a decrease of glucosamine incorporation into at least two host cell polypeptides, while the majority of cellular proteins are unaffected and glycosylation of a 47 kDa cellular protein is strongly induced. These selective alterations of protein glycosylation suggest that delta 12-PGJ2 affects a specific group of glycosylated proteins. The finding that cyclopentenone prostaglandins act on different events during the virus cycle explains the effectiveness of these compounds in controlling the replication of different types of viruses and presents an attractive new approach to antiviral chemotherapy.

Antiviral effect of short hyperthermic treatment at specific stages of vesicular stomatitis virus replication cycle

Starting from the observation that the antiviral activity of cyclopentenone prostaglandins is associated with the synthesis of a 70K heat shock protein (HSP70), we have analysed the effect of short hyperthermic treatment (HT) on HSP70 induction and virus production in monkey epithelial cells during the replication of vesicular stomatitis virus (VSV). The heat shock response, as determined by HSP70 synthesis, appeared to be unaltered in VSV-infected cells in the first 4 h following virus infection, after which time it started to decline. No induction of HSP70 synthesis was observed when HT was applied 8 h after VSV infection. A 20 min HT at 45 degrees C was effective in suppressing VSV multiplication by more than 90% when applied at specific stages of the virus replication cycle. Synthesis of virus proteins was not affected by HT, indicating that the target for the treatment is a post-translational event. The HT-induced block of virus replication appeared to be associated with inhibition of VSV G protein maturation and HSP70 induction.

Inhibition of Sendai virus replication by △12-prostaglandin J2: Induction of heat shock protein synthesis and alteration of protein glycosylation

delta 12-Prostaglandin J2 (delta 12-PGJ2), a natural dehydration product of prostaglandin D2 present in human body fluids, was shown to suppress Sendai virus replication in monkey kidney cells, at doses non-toxic to uninfected cells. Dramatic inhibition of virus production could be obtained at doses of delta 12-PGJ2 which did not inhibit cellular or viral protein synthesis, suggesting an effect on virus assembly and/or maturation. At the active concentration, delta 12-PGJ2 caused a decrease in glucosamine incorporation into the virus glycoproteins HN and F, and in at least one host cell polypeptide, while it did not affect most cellular glycoproteins and it induced the glycosylation of a 47-kDa cellular polypeptide. These effects were accompanied by the induction of heat shock protein synthesis, which was found to differ in its specificity and kinetics from induction by prostaglandin A1.

Effect of combined αIFN and prostaglandin A1 treatment on vesicular stomatitis virus replication and heat shock protein synthesis in epithelial cells

The antiviral activity of prostaglandin A (PGA) and interferons (IFNs) has been widely described. In the present report, we investigated the effect of combined alpha IFN and PGA1 treatment on vesicular stomatitis virus (VSV) replication and on heat shock protein (HSP) induction in monkey epithelia cells. In uninfected cells, PGA1 caused a dose-dependent induction of HSP70, HSP90 and HSP110, while alpha IFN did not affect HSP synthesis. Alpha-IFN suppressed VSV replication dose-dependently, even when cells were treated after virus infection. VSV protein synthesis was not affected by alpha IFN, indicating a block at the level of virus assembly or maturation. PGA1 caused a dose-dependent inhibition of VSV replication, and suppressed VSV protein synthesis at concentrations which induced the synthesis of high levels of HSP70. The combined treatment with low doses of alpha IFN or PGA1, which only moderately inhibited VSV replication when administered separately, was found to suppress VSV production by more than 95%, and resulted in a 3-fold increase of HSP70 synthesis as compared to PGA1 alone. These results demonstrate a co-operative effect of PGA1 and alpha IFN against VSV infection and suggest that alpha IFN can potentiate the cellular response to HSP induction in virus-infected cells.

Antiviral activity of cyclopentenone prostaglandins: Block of virus protein synthesis and induction of stress proteins in polarized monkey kidney cells

The antiviral activity of cyclopentenone prostaglandins (PGs) has been shown in different experimental models of DNA and RNA viruses, both in vitro and in vivo (1). A substantial block of virus replication ( > 95%) can be obtained at doses of PGs non-toxic for the host cell and that do not alter the synthesis of nucleic acids and proteins in uninfected cells. In most of the models studied PGs affect a late event in the virus replication cycle, causing specific alterations of the synthesis and/or maturation of one or more viral proteins (2,3). In this paper we describe the antiviral activity of A t 2 P G J 2, a cyclopentenone metabolite of arachidonic acid, derived from the dehydration of prostaglandin D2, in a monkey epithelial cell line, MA104, infected with Vesicular Stomatitis Virus (VSV).