Inhibition of Cyclooxygenase 2 Synthesis SuppressesHerpes simplexVirus Type 1 Reactivation

Emerging drugs for the treatment of herpetic keratitis

INTRODUCTION

Herpes simplex keratitis stands as a prominent factor contributing to infectious blindness among developed nations. On a global scale, over 60% of the population tests positive for herpes simplex virus type-1 (HSV-1). Despite these statistics, there is currently no vaccine available for the virus. Moreover, the conventional nucleoside drugs prescribed to patients are proving ineffective in addressing issues related to drug resistance, recurrence, latency, and the escalating risk of vision loss. Hence, it is imperative to continually explore all potential avenues to restrict the virus. This review article centers on the present treatment methods for HSV-1 keratitis (HSK), highlighting the ongoing clinical trials. It delves into the emerging drugs, their mode-of-action and future therapeutics.

AREAS COVERED

The review focuses on the significance of a variety of small molecules targeting HSV-1 lifecycle at multiple steps. Peer-reviewed articles and abstracts were searched in MEDLINE, PubMed, Embase, and clinical trial websites.

EXPERT OPINION

The exploration of small molecules that target specific pathways within the herpes lifecycle holds the potential for substantial impact on the antiviral pharmaceutical market. Simultaneously, the pursuit of disease-specific biomarkers has the capacity to usher in a transformative era in diagnostics within the field.

Insights of Valacyclovir in Treatment of Alzheimer's Disease: Computational Docking Studies and Scopolamine Rat Model

BACKGROUND

Alzheimer's Disease (AD) impairs memory and cognitive functions in the geriatric population and is characterized by intracellular deposition of neurofibrillary tangles, extracellular deposition of amyloid plaques, and neuronal degeneration. Literature suggests that latent viral infections in the brain act as prions and promote neurodegeneration. Memantine possesses both anti-viral and N-methyl-D-aspartate (NMDA) receptor antagonistic activity.

OBJECTIVES

This research was designed to evaluate the efficacy of antiviral agents, especially valacyclovir, a prodrug of acyclovir in ameliorating the pathology of AD based on the presumption that anti-viral agents targeting the Herpes Simplex Virus (HSV) can have a protective effect on neurodegenerative diseases like Alzheimer's disease.

METHODS

Thus, we evaluated acyclovir's potential activity by in-silico computational docking studies against acetylcholinesterase (AChE), butyrylcholinesterase (BuChE), and beta-secretase 1 (BACE-1). These findings were further evaluated by in-vivo scopolamine-induced cognitive impairment in rats. Two doses of valacyclovir, a prodrug of acyclovir (100 mg/kg and 150 mg/kg orally) were tested.

RESULTS

Genetic Optimisation for Ligand Docking scores and fitness scores of acyclovir were comparable to donepezil. Valacyclovir improved neurobehavioral markers. It inhibited AChE and BuChE (p<0.001) enzymes. It also possessed disease-modifying efficacy as it decreased the levels of BACE-1 (p<0.001), amyloid beta 1-42 (p<0.001), amyloid beta 1-40 (p<0.001), phosphorylatedtau (p<0.001), neprilysin (p<0.01), and insulin-degrading enzyme. It ameliorated neuroinflammation through decreased levels of tumour necrosis factor α (p<0.001), nuclear factor-kappa B (p<0.001), interleukin 6 (p<0.001), interleukin 1 beta (p<0.001), and interferon-gamma (p<0.001). It also maintained synaptic plasticity and consolidated memory. Histopathology showed that valacyclovir could restore cellular density and also preserve the dentate gyrus.

CONCLUSION

Valacyclovir showed comparable activity to donepezil and thus can be further researched for the treatment of Alzheimer's disease.

Evidence in the prevention of the recurrence of herpes simplex and herpes zoster keratitis after eye surgery

OBJECTIVE

Herpetic keratitis, either due to herpes simplex keratitis (HSK) or herpes zoster ophthalmicus (HZO), can recur after eye surgery.º Prophylaxis is postulated as necessary to avoid it. The objective of this study was to review the scientific evidence on the preventive methods used in the perioperative period in patients previously affected by HSK/HZO.

METHODS

An exhaustive search was carried out in the PubMed and Web of Science databases to identify relevant articles on prophylaxis and risk of recurrence of HSK/HZO in patients undergoing eye surgery up to 31 December 2019.

RESULTS

There is strong evidence that oral prophylaxis should be recommended after penetrating keratoplasty in patients who have previously had HSK/HZO. For other types of surgery, the evidence is less compelling. However, a latent period of inactivity should be considered between disease and oral prophylaxis.

CONCLUSIONS

Penetrating and lamellar keratoplasty, corneal crosslinking, cataract surgery, and photorefractive and phototherapeutic surgery cause an alteration of the subbasal nerve plexus of the cornea. Due to surgical trauma, as well as the modulation of the ocular immune response caused by steroids applied in the postoperative period, it is possible to induce the reactivation of HSK/HZO, which is common in some cases. Within this article, we discuss the available evidence for HSK/HZO prophylaxis in eye surgery. Further studies are necessary to define the real risk of HSK/HZO recurrence after ocular surgeries, particularly in cataract surgery, and to confirm the efficacy of perioperative prophylaxis with anti-HSK/HZO antivirals.

Effect of celecoxib against different developmental stages of experimental Schistosoma mansoni infection

Due to the high prevalence of schistosomiasis and the wide use of praziquantel solely for mass drug administration to control the disease, there is a great concern about the potential emergence of reduced susceptibility strains. This, together with the concern that praziquantel is ineffective against juvenile worms highlight the importance of developing an alternative anti-schistosomal drug. Using nonsteroidal anti-inflammatory drugs against schistosome infection is considerable. The present study evaluated the effect of oral administration of five days celecoxib regimen (20 mg/kg/day) against different developmental stages of Schistosoma mansoni infection. This regimen induced significant reduction in worm burden, tissue egg count, individual female fecundity and the mean percentage of immature and mature eggs with increased mean percentage of dead eggs. More importantly, celecoxib was more potent than praziquantel in all these parasitological parameters (except in the worm burden when given against the adult stage where the difference was statistically non-significant). Scanning and transmission electron microscopy of the adult worms revealed severe tegumental damage, laceration of the muscular layers and oedema of the syncytial layer. There was disruption of the testicular, ovarian and vitelline glandular tissues with signs of apoptosis and abnormalities of the spermatozoa and the oocytes. Additionally, celecoxib induced reduction in the number and the size of the hepatic granulomata and also amelioration of the hepatic tissue pathology.

Targeting Host Cellular Factors as a Strategy of Therapeutic Intervention for Herpesvirus Infections

Herpesviruses utilize various host factors to establish latent infection, survival, and spread disease in the host. These factors include host cellular machinery, host proteins, gene expression, multiple transcription factors, cellular signal pathways, immune cell activation, transcription factors, cytokines, angiogenesis, invasion, and factors promoting metastasis. The knowledge and understanding of host genes, protein products, and biochemical pathways lead to discovering safe and effective antivirals to prevent viral reactivation and spread infection. Here, we focus on the contribution of pro-inflammatory, anti-inflammatory, and resolution lipid metabolites of the arachidonic acid (AA) pathway in the lifecycle of herpesvirus infections. We discuss how various herpesviruses utilize these lipid pathways to their advantage and how we target them to combat herpesvirus infection. We also summarize recent development in anti-herpesvirus therapeutics and new strategies proposed or under clinical trials. These anti-herpesvirus therapeutics include inhibitors blocking viral life cycle events, engineered anticancer agents, epigenome influencing factors, immunomodulators, and therapeutic compounds from natural extracts.

Ocular surgery after herpes simplex and herpes zoster keratitis

PURPOSE

The recurrence of herpetic stromal keratitis (HSK) and herpes zoster ophthalmicus (HZO) has been reported after a variety of ocular surgeries. The aim of this study was to review the evidence on the preventive methods employed in the perioperative period in patients having undergone HSK/HZO.

METHODS

The PubMed and Web of Science databases were the main resources used to conduct the medical literature search. An extensive search was performed to identify relevant articles concerning the prophylaxis against and risk of HSK/HZO recurrence in patients undergoing ocular surgery up to December 31, 2019.

RESULTS

The disturbance of the corneal nerve plexus occurs during several ocular surgeries including penetrating keratoplasty, lamellar keratoplasty, corneal cross-linking, cataract surgery, as well as photorefractive and phototherapeutic procedures. Such trauma, as well as modulation of the ocular immunological response caused by steroids applied postoperatively, might engender the HSK/HZO reactivation which is not uncommon. There is strong evidence that oral prophylaxis should be recommended just after surgery in patients undergoing penetrating keratoplasty and having suffered from HSK/HZO. For other types of surgeries, the evidence is less compelling; nevertheless, a period of disease quiescence and oral prophylaxis should still be considered.

CONCLUSIONS

Within the article, we discuss the available evidence for HSK/HZO prophylaxis in ocular surgery. Additional studies would be required to define the real risk of HSK/HZO recurrence following eye surgeries, and particularly cataract surgery, and to confirm the utility of perioperative HSK/HZO prophylaxis.

Early Steps in Herpes Simplex Virus Infection Blocked by a Proteasome Inhibitor

Viruses commandeer host cell 26S proteasome activity to promote viral entry, gene expression, replication, assembly, and egress. Proteasomal degradation activity is critical for herpes simplex virus (HSV) infection. The proteasome inhibitor bortezomib (also known as Velcade and PS-341) is a clinically effective antineoplastic drug that is FDA approved for treatment of hematologic malignancies such as multiple myeloma and mantle cell lymphoma. Low nanomolar concentrations of bortezomib inhibited infection by HSV-1, HSV-2, and acyclovir-resistant strains. Inhibition coincided with minimal cytotoxicity. Bortezomib did not affect attachment of HSV to cells or inactivate the virus directly. Bortezomib acted early in HSV infection by perturbing two distinct proteasome-dependent steps that occur within the initial hours of infection: the transport of incoming viral nucleocapsids to the nucleus and the virus-induced disruption of host nuclear domain 10 (ND10) structures. The combination of bortezomib with acyclovir demonstrated synergistic inhibitory effects on HSV infection. Thus, bortezomib is a novel potential therapeutic for HSV with a defined mechanism of action.IMPORTANCE Viruses usurp host cell functions to advance their replicative agenda. HSV relies on cellular proteasome activity for successful infection. Proteasome inhibitors, such as MG132, block HSV infection at multiple stages of the infectious cycle. Targeting host cell processes for antiviral intervention is an unconventional approach that might limit antiviral resistance. Here we demonstrated that the proteasome inhibitor bortezomib, which is a clinically effective cancer drug, has the in vitro features of a promising anti-HSV therapeutic. Bortezomib inhibited HSV infection during the first hours of infection at nanomolar concentrations that were minimally cytotoxic. The mechanism of bortezomib's inhibition of early HSV infection was to halt nucleocapsid transport to the nucleus and to stabilize the ND10 cellular defense complex. Bortezomib and acyclovir acted synergistically to inhibit HSV infection. Overall, we present evidence for the repurposing of bortezomib as a novel antiherpesviral agent and describe specific mechanisms of action.

A series of in vitro and human studies of a novel lip cream formulation for protecting against environmental triggers of recurrent herpes labialis

Purpose

These studies describe the testing of a novel, daily-use lip cream designed for individuals with lips prone to recurrent herpes labialis (RHL) that protects against environmental triggers.

Subjects and methods

In vitro occlusive and in vitro and in vivo photoprotection analyses, a characterization of normal vs dry lips, and a randomized, evaluator-blinded, clinical trial that assessed the lip cream in healthy subjects with dry lips were conducted. In the clinical trial, subjects applied the lip cream or were untreated and evaluated using transepidermal water loss (TEWL), corneometry, visual assessments of lip dryness, expert photographic evaluations, and subject-rated outcomes.

Results

The lip cream’s in vitro water vapor transmission rate (84.1 g/(m² h)) indicated moderate occlusivity. The lip cream, but not placebo or control (water), reduced ultraviolet A (UVA)- and UVB-induced DNA damage, and tumor necrosis factor-α (EpiDerm^FT) and pros-taglandin E₂ release (EpiDerm^FT and EpiGingival™). The lip cream’s in vivo sun protection factor (SPF) was 12.2 (lower confidence limit, 11.3) and SPF/UVA protection factor ratio was 0.9. The characterization of dry vs normal lips identified differences in moisturization. In the clinical trial, the lip cream significantly decreased TEWL (difference: −7.19 [95% CI: −11.41, −2.98]; P<0.01), increased corneometry (difference: 4.62 [95% CI: 1.05, 8.19]; P<0.05), and reduced visual dryness (difference: −1.48 [95% CI: 2.24, −0.71]; P<0.001) compared to untreated subjects. Significant benefits were also observed on expert photographic assessments of scaling (difference: −0.89 [95% CI: −1.75, −0.03]; P< 0.05), cupping (difference: −1.50 [95% CI: −2.30, −0.70]; P<0.001), and healthy appearance (difference: −1.44 [95% CI: −2.29, −0.58]; P<0.01); differences in overall healthy appearance were not significant (P=0.51). Subject-rated assessments indicated improvements in cracking, dryness, and flaking in the lip cream group but worsening in untreated subjects.

Conclusion

These studies indicate that this novel, daily-use lip cream protects against UV radiation, drying, and chapping, which are established environmental RHL triggers.

Pathological processes activated by herpes simplex virus-1 (HSV-1) infection in the cornea

Herpes simplex virus type-1 (HSV-1) is a ubiquitous pathogen that infects a large majority of the human population worldwide. It is also a leading cause of infection-related blindness in the developed world. HSV-1 infection of the cornea begins with viral entry into resident cells via a multistep process that involves interaction of viral glycoproteins and host cell surface receptors. Once inside, HSV-1 infection induces a chronic immune-inflammatory response resulting in corneal scarring, thinning and neovascularization. This leads to development of various ocular diseases such as herpes stromal keratitis, resulting in visual impairment and eventual blindness. HSV-1 can also invade the central nervous system and lead to encephalitis, a relatively common cause of sporadic fetal encephalitis worldwide. In this review, we discuss the pathological processes activated by corneal HSV-1 infection and existing antiviral therapies as well as novel therapeutic options currently under development.

Feline calicivirus- and murine norovirus-induced COX-2/PGE2 signaling pathway has proviral effects

Cyclooxygenases (COXs)/prostaglandin E₂ (PGE₂) signaling pathways are known to modulate a variety of homeostatic processes and are involved in various pathophysiological conditions. COXs/PGE₂ signaling pathways have also been demonstrated to have proviral or antiviral effects, which appeared different even in the same virus family. A porcine sapovirus Cowden strain, a member of genus Sapovirus within the Caliciviridae family, induces strong COX-2/PGE₂ but transient COX-1/PGE₂ signaling to enhance virus replication. However, whether infections of other viruses in the different genera activate COXs/PGE₂ signaling, and thus affect the replication of viruses, remains unknown. In the present study, infections of cells with the feline calicivirus (FCV) F9 strain in the genus Vesivirus and murine norovirus (MNV) CW-1 strain in the genus Norovirus only activated the COX-2/PGE₂ signaling in a time-dependent manner. Treatment with pharmacological inhibitors or transfection of small interfering RNAs (siRNAs) against COX-2 enzyme significantly reduced the production of PGE₂ as well as FCV and MNV replications. The inhibitory effects of these pharmacological inhibitors against COX-2 enzyme on the replication of both viruses were restored by the addition of PGE₂. Silencing of COX-1 via siRNAs and inhibition of COX-1 via an inhibitor also decrease the production of PGE₂ and replication of both viruses, which can be attributed to the inhibition COX-1/PGE₂ signaling pathway. These data indicate that the COX-2/PGE₂ signaling pathway has proviral effects for the replication of FCV and MNV, and pharmacological inhibitors against these enzymes serve as potential therapeutic candidates for treating FCV and MNV infections.

HPV16 E7 increases COX-2 expression and promotes the proliferation of breast cancer

Breast cancer remains the leading cause of mortality worldwide. Human papilloma virus 16 (HPV16) may serve a function in the pathogenesis and development of breast cancer. However, the detection rate of HPV16 in breast carcinoma may vary by region. In the present study, the expression of HPV16 E7 in paraffin-embedded tissues from patients with breast cancer from North China was detected. Additionally, the molecular mechanisms underlying the function of HPV16 E7 in the proliferation of breast cancer cells were examined. The results demonstrated that the DNA of HPV16 E7 was detected in 30.5% of the samples, and that HPV16 E7 promoted the proliferation of breast cancer cells in vitro and in vivo. Additionally, HPV16 E7-mediated proliferation of breast cancer cells was suppressed in response to treatment with cyclooxygenase-2 (COX-2)-specific small interfering RNA and celecoxib. The results of the present study revealed that HPV16 E7 may promote the proliferation of breast cancer cells by upregulating COX-2, suggesting that COX-2 may be a potential therapeutic target for HPV16 E7-mediated progression of breast cancer.

Migraine Headache Treated with Famciclovir and Celecoxib: A Case Report

INTRODUCTION

Herpes simplex virus (HSV) has been speculated to play a role in migraine headache pathophysiology. We present the first successful migraine headache treatment with therapy specifically targeting HSV infection.

CASE PRESENTATION

A previously healthy 21-year-old white woman presented with a severe headache and was diagnosed with severe migraine headache disorder. She initially was treated with standard migraine headache medications without symptomatic improvement. She was then given famciclovir and celecoxib. The patient fully recovered within days and continues to enjoy significant reduction in severity and frequency of symptoms.

DISCUSSION

Famciclovir and celecoxib may work synergistically against HSV. The virus may play a role in the pathophysiology of migraine headaches, and this is the first case report of successful migraine headache treatment with these medications. Further studies are needed to elucidate the efficacy of these medications in treating migraine disorder.

Cyclooxygenase-2 facilitates dengue virus replication and serves as a potential target for developing antiviral agents

Cyclooxygenase-2 (COX-2) is one of the important mediators of inflammation in response to viral infection, and it contributes to viral replication, for example, cytomegalovirus or hepatitis C virus replication. The role of COX-2 in dengue virus (DENV) replication remains unclear. In the present study, we observed an increased level of COX-2 in patients with dengue fever compared with healthy donors. Consistent with the clinical data, an elevated level of COX-2 expression was also observed in DENV-infected ICR suckling mice. Using cell-based experiments, we revealed that DENV-2 infection significantly induced COX-2 expression and prostaglandin E₂ (PGE₂) production in human hepatoma Huh-7 cells. The exogenous expression of COX-2 or PGE₂ treatment dose-dependently enhanced DENV-2 replication. In contrast, COX-2 gene silencing and catalytic inhibition sufficiently suppressed DENV-2 replication. In an ICR suckling mouse model, we identified that the COX-2 inhibitor NS398 protected mice from succumbing to life-threatening DENV-2 infection. By using COX-2 promoter-based analysis and specific inhibitors against signaling molecules, we identified that NF-κB and MAPK/JNK are critical factors for DENV-2-induced COX-2 expression and viral replication. Altogether, our results reveal that COX-2 is an important factor for DENV replication and can serve as a potential target for developing therapeutic agents against DENV infection.

A famciclovir + celecoxib combination treatment is safe and efficacious in the treatment of fibromyalgia

Objective

Infections and other stressors have been implicated in the development of fibromyalgia. We hypothesized that these stressors could result in recurrent reactivations of latent herpes virus infections, which could lead to the development of fibromyalgia. This study evaluated a famciclovir + celecoxib drug combination (IMC-1), active against suspected herpes virus reactivation and infection, for the treatment of fibromyalgia.

Methods

A total of 143 fibromyalgia patients were enrolled at 12 sites in a 16-week, double-blinded, placebo-controlled proof-of-concept trial. Randomized patients received either IMC-1 or placebo in a 1:1 ratio. Outcome measures included a 24-hour recall pain Numerical Rating Scale, the Revised Fibromyalgia Impact Questionnaire (FIQ-R), the Patient’s Global Impression of Change (PGIC) questionnaire, the Multidimensional Fatigue Inventory, the NIH Patient-Reported Outcomes Measurement Information System (PROMIS), and the Beck Depression Inventory-II conducted at baseline and weeks 6, 12, and 16 of the study.

Results

A significant decrease in fibromyalgia-related pain was observed for patients on IMC-1 treatment versus placebo. PGIC response rates were significantly improved with IMC-1 treatment. Overall, patient self-reported functioning, as measured by the FIQ-R, was significantly improved. Fatigue was also significantly improved as measured by the PROMIS fatigue inventory. The safety profile was encouraging. Despite the celecoxib component of IMC-1, gastrointestinal and nervous system treatment emergent adverse events were reported less frequently in the IMC-1 group, and study completion rates favored IMC-1 treatment.

Conclusion

IMC-1 was efficacious and safe in treating symptoms of fibromyalgia, supporting the hypothesis that herpes virus infections may contribute to this syndrome. Improved retention rates, decreased adverse event rates, and evidence of efficacy on a broad spectrum of outcome measures are suggestive that IMC-1 may represent an effective, novel treatment for fibromyalgia.

Activation of NF-κB signaling pathway in HSV-1-induced mouse facial palsy: Possible relation to therapeutic effect of glucocorticoids

It has been documented that infection of herpes simplex virus type 1 (HSV-1) contributes to the initiation of Bell's palsy. However, the exact mechanisms responsible for this disorder have not been fully elucidated to date. A mouse model of facial palsy induced by HSV-1 provides an opportunity to investigate the alteration in activities of nuclear factor-kappa B (NF-κB) and its consequent effect on two key inflammatory factors, i.e., tumor necrosis factor (TNF)-α and cyclooxygenase-2 (COX-2), as well as the effect of glucocorticoids (GCs) in this work. I-kappa B (IκB)-α phosphorylation and NF-κB nuclear translocation were measured by western blotting, and NF-κB/DNA binding activity was assessed by electrophoretic mobility shift assay (EMSA). Results showed the IκB-α phosphorylation and degradation as well as NF-κB activation in a time-dependent manner. The expression of TNF-α and COX-2 were determined by real-time polymerase chain reaction (PCR), western blotting and/or enzyme-linked immunosorbent assay (ELISA) respectively. Concomitant with the activation, the expression and secretion of TNF-α and COX-2 were rapidly induced in HSV-1-infected paralyzed mice. Conversely, the activation of NF-κB and up-regulation of TNF-α and COX-2 were blocked by pretreatment with NF-κB inhibitor pyrrolidine dithiocarbamate (PDTC) before being inoculated with HSV-1 to mice. In addition, GCs inhibited the nuclear translocation and DNA binding activity of NF-κB via inhibiting IκB-α degradation. Meanwhile, TNF-α production and COX-2 expression were significantly reduced by GCs. In conclusion, HSV-1 inoculation induced the activation of NF-κB, expression and secretion of TNF-α and COX-2 in the facial paralyzed mice, while, glucocorticoid effectively down-regulated TNF-α and COX-2 expression in HSV-1-induced paralyzed mice.

The role of cyclooxygenase in multiplication and reactivation of HSV-1 in vestibular ganglion neurons

Reactivation of latent herpes simplex type 1 (HSV-1) and nerve inflammation have been shown to be involved in vertigo-related vestibular pathogenesis. Treatments of such diseases have been less than perfect. Nonsteroidal anti-inflammatory drugs (NSAIDs) have been reported to suppress reactivation of HSV-1 in trigeminal ganglions. However, whether this drug can affect reactivation of HSV-1 in vestibular ganglions is unclear. Due to the difficulties of constructing in vivo animal models, in this study, we developed a vestibular ganglion culture system, in which vestibular neurons were latently or lytically infected with HSV-1. Indomethacin and celecoxib were selected to measure their effects on HSV-1. Trichostatin A was used to reactivate HSV-1 in latently infected neurons. Cycloxygenase-2, which is the target of NSAIDs, was induced by HSV-1 in the lytically infected cultures, with an increase of 14-fold. Although it appeared that indomethacin and celecoxib showed limited but concentration-dependent inhibition effects on viral production under our condition, indomethacin decreased reactivation rate of HSV-1 by about 20%. Though more in vitro or in vivo studies are needed to confirm the effects of the drugs, our study may provide a potential way to investigate the mechanism of HSV-related vestibular pathogenesis as well as new treatments of vertigo-related diseases.

Cyclooxygenase-2-prostaglandin E2-eicosanoid receptor inflammatory axis: a key player in Kaposi's sarcoma-associated herpes virus associated malignancies

The role of cyclooxygenase-2 (COX-2), its lipid metabolite prostaglandin E2 (PGE2), and Eicosanoid (EP) receptors (EP; 1-4) underlying the proinflammatory mechanistic aspects of Burkitt's lymphoma, nasopharyngeal carcinoma, cervical cancer, prostate cancer, colon cancer, and Kaposi's sarcoma (KS) is an active area of investigation. The tumorigenic potential of COX-2 and PGE2 through EP receptors forms the mechanistic context underlying the chemotherapeutic potential of nonsteroidal anti-inflammatory drugs (NSAIDs). Although role of the COX-2 is described in several viral associated malignancies, the biological significance of the COX-2/PGE2/EP receptor inflammatory axis is extensively studied only in Kaposi's sarcoma-associated herpes virus (KSHV/HHV-8) associated malignancies such as KS, a multifocal endothelial cell tumor and primary effusion lymphoma (PEL), a B cell-proliferative disorder. The purpose of this review is to summarize the salient findings delineating the molecular mechanisms downstream of COX-2 involving PGE2 secretion and its autocrine and paracrine interactions with EP receptors (EP1-4), COX-2/PGE2/EP receptor signaling regulating KSHV pathogenesis and latency. KSHV infection induces COX-2, PGE2 secretion, and EP receptor activation. The resulting signal cascades modulate the expression of KSHV latency genes (latency associated nuclear antigen-1 [LANA-1] and viral-Fas (TNFRSF6)-associated via death domain like interferon converting enzyme-like- inhibitory protein [vFLIP]). vFLIP was also shown to be crucial for the maintenance of COX-2 activation. The mutually interdependent interactions between viral proteins (LANA-1/vFLIP) and COX-2/PGE2/EP receptors was shown to play key roles in the biological mechanisms involved in KS and PEL pathogenesis such as blockage of apoptosis, cell cycle regulation, transformation, proliferation, angiogenesis, adhesion, invasion, and immune-suppression. Understanding the COX-2/PGE2/EP axis is very important to develop new safer and specific therapeutic modalities for KS and PEL. In addition to COX-2 being a therapeutic target, EP receptors represent ideal targets for pharmacologic agents as PGE2 analogues and their blockers/antagonists possess antineoplastic activity, without the reported gastrointestinal and cardiovascular toxicity observed with few a NSAIDs.

Establishment of SYBR green-based qPCR assay for rapid evaluation and quantification for anti-Hantaan virus compounds in vitro and in suckling mice

Hantaan viruses cause two severe diseases lacking efficient treatment, yet no effective prophylactic vaccines are available. Continued exploration of alternative antiviral agents to treat hantavirus-related syndromes remains compulsory. The fluorescence-based quantitative real-time PCR (qPCR) has become the touchstone for target gene quantification. In the present study, standard curves for Hantaan virus (HTNV), mouse, and human glyceraldehyde-3-phosphate dehydrogenase (GAPDH) were generated by serial 10-fold dilutions of the constructed recombinant plasmid pGEM-T/HTNV, pGEM-T/mouse-GAPDH, and pGEM-T/human-GAPDH, respectively. Comparisons between the indirect immunofluorescence assay and qPCR assay in the detection of HTNV-infected Vero E6 cells showed improved detection limit and sensitivity of latter method. To characterize the inhibitory effect of several conventional antivirals (arbidol and ribavirin) and unconventional antivirals (indomethacin and curcumin) on HTNV, the levels of viral RNAs were measured for 4 days post-treatment of HTNV-infected Vero E6 cells and 18 days post-inoculation of HTNV-infected suckling mice. Our results validated that HTNV was sensitive to ribavirin and arbidol treatment, while indomethacin and curcumin may also be therapeutically effective in treating HTNV infection. As a result, the establishment and application of qPCR may be a useful tool for the evaluation of potential antivirals for Hantaan virus infection in vitro and in vivo.

Rabbit and mouse models of HSV-1 latency, reactivation, and recurrent eye diseases

The exact mechanisms of HSV-1 establishment, maintenance, latency, reactivation, and also the courses of recurrent ocular infections remain a mystery. Comprehensive understanding of the HSV-1 disease process could lead to prevention of HSV-1 acute infection, reactivation, and more effective treatments of recurrent ocular disease. Animal models have been used for over sixty years to investigate our concepts and hypotheses of HSV-1 diseases. In this paper we present descriptions and examples of rabbit and mouse eye models of HSV-1 latency, reactivation, and recurrent diseases. We summarize studies in animal models of spontaneous and induced HSV-1 reactivation and recurrent disease. Numerous stimuli that induce reactivation in mice and rabbits are described, as well as factors that inhibit viral reactivation from latency. The key features, advantages, and disadvantages of the mouse and rabbit models in relation to the study of ocular HSV-1 are discussed. This paper is pertinent but not intended to be all inclusive. We will give examples of key papers that have reported novel discoveries related to the review topics.

The kinetics of herpes virus on the ocular surface and suppression of its reactivation

Herpes simplex virus type 1 (HSV-1) establishes a latent infection in sensory neurons that can sometimes be reactivated. HSV-1 keratitis often recurs and can be vision threatening. Reactivation of the latent virus can be stimulated by stress, immunosuppression, trauma, adrenergic iontophoresis, and UV radiation. Healthy and asymptomatic individuals are known to shed HSV-1, and this is a major factor in the spread of the virus. We investigated the frequency of shedding of HSV-1 DNA in tears of dry eye patients and individuals with conjunctivitis. Subjects were divided into 3 groups: normal (12 eyes), dry eye (11 eyes), and conjunctivitis (15 eyes). Quantitative real-time polymerase chain reaction was used for HSV DNA detection. The incidences of HSV positivity in the normal, dry eye, and conjunctivitis groups were 1 of 12 (8.3%), 3 of 11 (27.3%), and 4 of 15 (26.7%), respectively. We have previously shown that bromfenac sodium eye drops, intramuscular adenosine monophosphate, and geldanamycin effectively lower HSV-1 recurrence rates in a mouse model. Recently, we also found that nuclear factor κ-B, an IκB kinase-β inhibitor, could be a candidate for reducing HSV-1 reactivation. We sampled recipients' corneal buttons during keratoplasty and performed polymerase chain reaction. Cytomegalovirus (CMV) DNA was detected in corneas obtained from some patients, and the copy number of the detected CMV DNA was quantified. CMV DNA-positive samples were taken from 2 of the 3 patients with ocular pemphigoid; thus, in future work, the relationship between CMV in the cornea and the incidence/onset of ocular diseases of the anterior segment needs to be evaluated.

Ocular herpes simplex virus: how are latency, reactivation, recurrent disease and therapy interrelated?

Most humans are infected with herpes simplex virus (HSV) type 1 in early childhood and remain latently infected throughout life. While most individuals have mild or no symptoms, some will develop destructive HSV keratitis. Ocular infection with HSV-1 and its associated sequelae account for the majority of corneal blindness in industrialized nations. Neuronal latency in the peripheral ganglia is established when transcription of the viral genome is repressed (silenced) except for the latency-associated transcripts and microRNAs. The functions of latency-associated transcripts have been investigated since 1987. Roles have been suggested relating to reactivation, establishment of latency, neuronal protection, antiapoptosis, apoptosis, virulence and asymptomatic shedding. Here, we review HSV-1 latent infections, reactivation, recurrent disease and antiviral therapies for the ocular HSV diseases.

Anti-influenza virus activity of tricin, 4',5,7-trihydroxy-3',5'-dimethoxyflavone

BACKGROUND

We examined the anti-influenza virus activity of tricin, 4',5,7-trihydroxy-3',5'-dimethoxyflavone, against five viruses: A/Solomon islands/3/2006 (H1N1), A/Hiroshima/52/2005 (H3N2), A/California/07/2009 (H1N1pdm), A/Narita/1/2009 (H1N1pdm) and B/Malaysia/2506/2004 strains in vitro and against A/PR/8/34 virus in vivo.

METHODS

The effect of tricin was studied by an infectious virus yield reduction assay. The anti-influenza virus mechanism of the tricin was examined by western blot analysis, real-time reverse transcriptase PCR analysis, haemagglutination inhibition (HI) assay and neuraminidase (NA) inhibition assay. The anti-influenza virus efficacy of tricin was further examined in a murine influenza virus infection model.

RESULTS

Tricin of 3.3 to 30 μM significantly reduced seasonal A (H1N1), (H3N2) viruses, novel A (H1N1pdm) virus, as well as B virus in a dose-dependent manner. The 50% effective concentrations of tricin were 3.4 μM for seasonal A (H3N2) virus, 4.9 μM for B virus and 8.2 μM for A/Narita (H1N1pdm) virus. Tricin decreased the expression of haemagglutinin (HA) protein and matrix (M) protein, and messenger RNA expression of HA and M of influenza virus in the infected cells. Tricin exhibited little or no effects on influenza virus HI and NA activities. In the mouse infection model, tricin was significantly effective in reducing body weight loss, and also effective in prolonging survival times of infected mice.

CONCLUSIONS

Tricin was indicated to possess anti-influenza virus activity and to ameliorate body weight loss and survival rate of influenza-A-virus-infected mice. Tricin is a novel compound with potential anti-influenza virus activity in vitro and in vivo.

A novel HLA (HLA-A*0201) transgenic rabbit model for preclinical evaluation of human CD8+ T cell epitope-based vaccines against ocular herpes

We introduced a novel humanized HLA-A*0201 transgenic (HLA Tg) rabbit model to assess the protective efficacy of a human CD8(+) T cell epitope-based vaccine against primary ocular herpes infection and disease. Each of the three immunodominant human CD8(+) T cell peptide epitopes from HSV-1 glycoprotein D (gD(53-61), gD(70-78), and gD(278-286)) were joined with a promiscuous human CD4(+) T cell peptide epitope (gD(49-82)) to construct three separate pairs of CD4-CD8 peptides. Each CD4-CD8 peptide pair was then covalently linked to an N(epsilon)-palmitoyl-lysine residue via a functional base lysine amino group to construct CD4-CD8 lipopeptides. HLA Tg rabbits were immunized s.c. with a mixture of the three CD4-CD8 HSV-1 gD lipopeptides. The HSV-gD-specific T cell responses induced by the mixture of CD4-CD8 lipopeptide vaccine and the protective efficacy against acute virus replication and ocular disease were determined. Immunization induced HSV-gD(49-82)-specific CD4(+) T cells in draining lymph node (DLN); induced HLA-restricted HSV-gD(53-61), gD(70-78), and gD(278-286)-specific CD8(+) T cells in DLN, conjunctiva, and trigeminal ganglia and reduced HSV-1 replication in tears and corneal eye disease after ocular HSV-1 challenge. In addition, the HSV-1 epitope-specific CD8(+) T cells induced in DLNs, conjunctiva, and the trigeminal ganglia were inversely proportional with corneal disease. The humanized HLA Tg rabbits appeared to be a useful preclinical animal model for investigating the immunogenicity and protective efficacy of human CD8(+) T cell epitope-based prophylactic vaccines against ocular herpes. The relevance of HLA Tg rabbits for future investigation of human CD4-CD8 epitope-based therapeutic vaccines against recurrent HSV-1 is discussed.

Alzheimer's disease and infection: do infectious agents contribute to progression of Alzheimer's disease?

Infection with several important pathogens could constitute risk factors for cognitive impairment, dementia, and Alzheimer's disease (AD) in particular. This review summarizes the data related to infectious agents that appear to have a relationship with AD. Infections with herpes simplex virus type 1, picornavirus, Borna disease virus, Chlamydia pneumoniae, Helicobacter pylori, and spirochete were reported to contribute to the pathophysiology of AD or to cognitive changes. Based on these reports, it may be hypothesized that central nervous system or systemic infections may contribute to the pathogenesis or pathophysiology of AD, and chronic infection with several pathogens should be considered a risk factor for sporadic AD. If this hypothesis holds true, early intervention against infection may delay or even prevent the future development of AD.

Eicosanoids influence insect susceptibility to nucleopolyhedroviruses

Nine pharmaceutical inhibitors of eicosanoid biosynthesis (e.g., bromophenacyl bromide, clotrimazole, diclofenamic acid, esculetin, flufenamic acid, indomethacin, nimesulide, sulindac, tolfenamic acid) that increased the susceptibility of the gypsy moth, Lymantria dispar (L.), to the nucleopolyhedrovirus LdMNPV were tested against the beet armyworm Spodoptera exigua (Hübner), the corn earworm Helicoverpa zea (Boddie) and the fall armyworm Spodoptera frugiperda (J.E. Smith) and their respective NPVs to determine whether these compounds also alter the susceptibility of these insects. The susceptibility of the beet armyworm was increased by six inhibitors (bromophenacyl bromide, clotrimazole, diclofenic acid, esculetin, flufenamic acid, nimesulide). The susceptibility of the fall armyworm was increased by seven inhibitors, (bromophenacyl bromide, diclofenamic acid, esculetin, indomethacin, nimesulide, sulindac, tolfenamic acid), whereas the susceptibility of the corn earworm was increased by only one inhibitor (sulindac). The influence of the cyclooxygenase inhibitor, indomethacin was expressed in a concentration-related manner in beet armyworms. We infer from these findings that eicosanoids, including prostaglandins and lipoxygenase products, act in insect anti-viral defenses.

Nucleoside diphosphate kinase/Nm23 and Epstein-Barr virus

Nm23-H1 was discovered as the first metastasis suppressor gene about 20 years ago. Since then, extensive work has contributed to understanding its role in various cellular signaling pathways. Its association with a range of human cancers as well as its ability to regulate cell cycle and suppress metastasis has been explored. We have determined that the EBV-encoded nuclear antigens, EBNA3C and EBNA1, required for EBV-mediated lymphoproliferation and for maintenance EBV genome extrachromosomally in dividing mammalian cells, respectively, target and disrupt the physiological role of Nm23-H1 in the context of cell proliferation and cell migration. This review will focus on the interaction of Nm23-H1 with the Epstein-Barr virus nuclear antigens, EBNA3C and EBNA1 and the functional significance of this interaction as it relates to EBV pathogenesis.

A double-blind placebo-controlled study to evaluate valacyclovir alone and with aspirin for asymptomatic HSV-1 DNA shedding in human tears and saliva

PURPOSE

To test the effect of valacyclovir alone and with aspirin on the asymptomatic shedding of HSV-1 DNA in tears and saliva of healthy individuals. METHOD. The subjects (n = 45) were randomized into three groups without regard to age, sex, or race. Group 1 (n = 14) received the placebo, group 2 (n = 15) received a dose of 500 mg valacyclovir once daily, and group 3 (n = 16) received a dose of 500 mg valacyclovir once daily and 350 mg aspirin twice daily for 30 days. Ocular and oral swabs were collected twice daily for 30 days. DNA was extracted from all swabs and HSV-1 DNA copy numbers were determined. Statistical analysis was performed to compare the DNA copy numbers of the three groups.

RESULTS

There was no significant difference in the HSV-1 DNA copy numbers in the tears or saliva among any of the three treatment groups. The mean copy numbers +/- SE of mean (SEM) of HSV-1 DNA in tears were 340 +/- 35, 1074 +/- 320, and 630 +/- 51 for groups 1, 2, and 3, and in saliva were 238 +/- 35, 963 +/- 462, and 493 +/- 25, respectively, for groups 1, 2, and 3.

CONCLUSIONS

No correlation was found between HSV-1 shedding and valacyclovir and valacyclovir with aspirin treatment. The HSV-1 DNA copy number was not reduced by treatment with 500 mg of valacyclovir daily or with a combination of daily valacyclovir (500 mg) plus twice-daily doses of aspirin (350 mg) over 30 days.

Cyclooxygenase (COX)-inhibiting drug reduces HSV-1 reactivation in the mouse eye model

PURPOSE

To examine the effects of COX inhibitors on suppressing HSV-1 reactivation in a mouse model.

METHODS

BALB/c mice were latently infected with HSV-1 and treated by 0.1% bromfenac Na eye drops, 0.1% pranoprofen eye drops, 0.1 mg oral etodolac 4 times/day, and saline for 4 days. After reactivating the latent HSV-1, we swabbed the mouse ocular surface for the culture of the infectious virus and assessed the viral loads in the eyes and trigeminal ganglia (TGs) using real-time PCR to determine the treatment efficacies.

RESULTS

With stimulated reactivation, 10 of 24 (41.7%), 5 of 10 (50.0%), 17 of 25 (68%), and 16 of 22 eyes (72.7%) showed positive swab results in the bromfenac Na, etodolac, pranoprofen, and saline groups, respectively; and a significant difference was seen only between the bromfenac Na and saline groups (p = 0.033). None of the three drug-treated groups showed any significant difference from the saline group in the viral DNA in the eyes and TGs (p > 0.05).

CONCLUSIONS

Bromfenac Na eye drops can suppress HSV-1 reactivation.

Inhibition of cyclooxygenase activity blocks cell-to-cell spread of human cytomegalovirus

Human cytomegalovirus has previously been shown to induce the accumulation of cyclooxygenase-2 RNA, protein, and enzyme activity. High doses of cyclooxygenase inhibitors substantially block viral replication in cultured fibroblasts. However, doses corresponding to the level of drug achieved in the plasma of patients have little effect on the replication of human cytomegalovirus in cultured cells. Here, we demonstrate that two nonsteroidal anti-inflammatory drugs, tolfenamic acid and indomethacin, markedly reduce direct cell-to-cell spread of human cytomegalovirus in cultured fibroblasts. The block is reversed by addition of prostaglandin E2, proving that it results from the action of the drugs on cyclooxygenase activity. Because direct cell-to-cell spread likely contributes importantly to pathogenesis of the virus, we suggest that nonsteroidal anti-inflammatory drugs might help to control human cytomegalovirus infections in conjunction with other anti-viral treatments.

Ocular HSV-1 latency, reactivation and recurrent disease

Ocular infection with HSV-1 continues to be a serious clinical problem despite the availability of effective antivirals. Primary infection with HSV-1 can involve ocular and adenaxial sites and can manifest as blepharitis, conjunctivitis, or corneal epithelial keratitis. After initial ocular infection, HSV-1 can establish latent infection in the trigeminal ganglia for the lifetime of the host. During latency, the viral genome is retained in the neuron without producing viral proteins. However, abundant transcription occurs at the region encoding the latency-associated transcript, which may play significant roles in the maintenance of latency as well as neuronal reactivation. Many host and viral factors are involved in HSV-1 reactivation from latency. HSV-1 DNA is shed into tears and saliva of most adults, but in most cases this does not result in lesions. Recurrent disease occurs as HSV-1 is carried by anterograde transport to the original site of infection, or any other site innervated by the latently infected ganglia, and can reinfect the ocular tissues. Recurrent corneal disease can lead to corneal scarring, thinning, stromal opacity and neovascularization and, eventually, blindness. In spite of intensive antiviral and anti-inflammatory therapy, a significant percentage of patients do not respond to chemotherapy for herpetic necrotizing stromal keratitis. Therefore, the development of therapies that would reduce asymptomatic viral shedding and lower the risks of recurrent disease and transmission of the virus is key to decreasing the morbidity of ocular herpetic disease. This review will highlight basic HSV-1 virology, and will compare the animal models of latency, reactivation, and recurrent ocular disease to the current clinical data.

Eicosanoid biosynthesis inhibitors increase the susceptibility of Lymantria dispar to nucleopolyhedrovirus LdMNPV

Eighteen pharmaceutical inhibitors of eicosanoid biosynthesis were tested for their effects on gypsy moth, Lymantria dispar and its susceptibility to the nucleopoly-hedrovirus LdMNPV. None of the inhibitors tested had any detrimental effects upon larval growth and development. Treatment with nine inhibitor/NPV combinations (e.g., bromophenacylbromide, clotrimazole, dexamethasone, esculetin, flufenamic acid, indomethacin, nimesulide, sulindac, tolfenamic acid) resulted in 3.5- to 6.6-fold reductions in LC(50)s. Larvae treated with several other COX inhibitors did not yield significant LC(50) reductions. We infer that eicosanoids act in insect defense responses to viral infection. Eicosanoids may act at three levels of insect immune reactions to viral infection, organismal (febrile response), cellular (hemocytic microaggregation, nodulation and plasmatocytes spreading reactions) and intracellular level (mechanisms responsible for insect permissiveness to viral replication).

Cycloxygenase-2 activity promotes cognitive deficits but not increased amyloid burden in a model of Alzheimer’s disease in a sex-dimorphic pattern

Administration of non-steroidal anti-inflammatory agents reduces the risk of developing Alzheimer's disease in normal aging populations, an effect that may occur from inhibition of the cyclooxygenases, the rate-limiting enzymes in the formation of prostaglandins. In this study, we investigated whether increased activity of cyclooxygenase-2 (COX-2), the inducible isoform of cyclooxygenase, potentiates disease progression in a transgenic mouse model of Alzheimer's disease. To study the functional effects of COX-2 activity, male and female bigenic mice (amyloid precursor protein with Swedish mutation [APPswe]-presenilin-1 protein with deletion of exon 9 [PS1dE9] and trigenic COX-2/APPswe-PS1dE9) were behaviorally tested +/-administration of the selective COX-2 inhibitor celecoxib. Behavioral testing included a three-trial Y maze that measures spatial working and recognition memories and an open field task that tested levels of hyperactivity. Overexpression of COX-2 in APPswe-PS1dE9 mice resulted in specific deficits in spatial working memory in female but not male mice. These sex-specific deficits were abolished by pharmacological inhibition of COX-2 activity. Importantly, COX-2-associated deficits were dependent on co-expression of all three transgenes since COX-2 single transgenic and APPswe-PS1dE9 bigenic mice showed normal memory. Quantification of amyloid plaque load and total Abeta 40 and 42 peptides did not reveal significant differences in trigenic versus bigenic mice treated with either vehicle or celecoxib. Taken together, these data indicate an interaction between the effects of COX-2 and Abeta peptides on cognition that occurs in a sex-specific manner in the absence of significant changes in amyloid burden. These findings suggest that pathological activation of COX-2 may potentiate the toxicity of Abeta peptides, particularly in females, without significantly affecting Abeta accumulation.

Biological interactions between herpesviruses and cyclooxygenase enzymes

Decades ago, medical researchers noted that non-steroidal anti-inflammatory drugs (NSAIDs), for example aspirin and indomethacin, modulate primary herpesvirus infections and diminish reactivation of latent herpesvirus infections. NSAIDs inhibit cyclooxygenase (COX) enzymes, molecules necessary for generation of prostaglandins. Numerous studies indicate that herpesvirus infections elicit elevated levels of cyclooxygenase 2 (COX-2) with a resultant increase in prostaglandin E(2) levels (PGE(2)). Thus, the biochemical pathway underlying the anti-herpetic mechanism of NSAIDs is linked to the inhibition of COX. The precise roles of COX-2 and PGE(2) in the viral life cycle are unknown. However, among the alphaherpesvirus, betaherpesvirus and gammaherpesvirus subfamilies, evolutionarily conserved mechanisms ensure modulated expression of COX molecules, underscoring their importance in viral replication and virus-host interactions.

Senile plaques in Alzheimer's diseased brains: possible association of beta-amyloid with herpes simplex virus type 1 (HSV-1) L-particles

The characteristic insoluble, senile (neuritic) plaques found extracellularly in brains of patients with Alzheimer's disease (AD) contain the fibrillar form of beta-amyloid (Abeta42). A substantial proportion of autopsied elderly brains have demonstrated DNA evidence of herpes simplex virus type 1 (HSV-1) infiltration. HSV-1-infected cells produce significant quantities of non-infectious, non-DNA-containing light particles (L-particles) comprised of viral envelope and tegument proteins. HSV-induced L-particles can be exocytosed out of their host cells. This report advances the hypothesis that (1) Abeta binds to L-particles; (2) Abeta permeabilizes L-particles, destroying the integrity of the envelope and allowing the contained tegument proteins to spill into the extracellular space; and (3) these events are followed by a conformational shift of Abeta into its fibrillar form, physically trapping the L-particle-derived substances and resulting in the plaques characteristic of AD. These hypotheses are supported by reports of biomolecular changes and pathophysiologies which have been simultaneously observed in both AD- and HSV-infected brains.