NVN1000, a novel nitric oxide-releasing compound, inhibits HPV-18 virus production by interfering with E6 and E7 oncoprotein functions

IDR-targeting compounds suppress HPV genome replication via disruption of phospho-BRD4 association with DNA damage response factors

Compounds binding to the bromodomains of bromodomain and extra-terminal (BET) family proteins, particularly BRD4, are promising anticancer agents. Nevertheless, side effects and drug resistance pose significant obstacles in BET-based therapeutics development. Using high-throughput screening of a 200,000-compound library, we identified small molecules targeting a phosphorylated intrinsically disordered region (IDR) of BRD4 that inhibit phospho-BRD4 (pBRD4)-dependent human papillomavirus (HPV) genome replication in HPV-containing keratinocytes. Proteomic profiling identified two DNA damage response factors-53BP1 and BARD1-crucial for differentiation-associated HPV genome amplification. pBRD4-mediated recruitment of 53BP1 and BARD1 to the HPV origin of replication occurs in a spatiotemporal and BRD4 long (BRD4-L) and short (BRD4-S) isoform-specific manner. This recruitment is disrupted by phospho-IDR-targeting compounds with little perturbation of the global transcriptome and BRD4 chromatin landscape. The discovery of these protein-protein interaction inhibitors (PPIi) not only demonstrates the feasibility of developing PPIi against phospho-IDRs but also uncovers antiviral agents targeting an epigenetic regulator essential for virus-host interaction and cancer development.

The Antiviral Effect of Berdazimer Sodium on Molluscum Contagiosum Virus Using a Novel In Vitro Methodology

Molluscum contagiosum (MC) is characterized by skin lesions containing the highly contagious molluscum contagiosum poxvirus (MCV). MCV primarily infects children, with one US Food and Drug Administration (FDA)-approved drug-device treatment in use but no approved medications. Assessing antivirals is hindered by the inability of MCV to replicate in vitro. Here, we use vaccinia virus as a surrogate to provide evidence of the anti-poxvirus properties of berdazimer sodium, a new chemical entity, and the active substance in berdazimer gel, 10.3%, a nitric oxide-releasing topical in phase 3 development for the treatment of MC. We show that berdazimer sodium reduced poxvirus replication and, through a novel methodology, demonstrate that cells infected with drug-treated MCV virions have reduced early gene expression. Specifically, this is accomplished by studying the nuclear factor kappa-light-chain-enhancer of activated B cell (NF-kB)-blocking protein MC160 as an example of an early gene. The results provide a plausible unique antiviral mechanism of action supporting increased MCV resolution observed in patients treated with berdazimer gel, 10.3% and describe a novel methodology that overcomes limitations in investigating MCV response in vitro to a potential new MC topical medication.

Strategies of Pathogens to Escape from NO-Based Host Defense

Nitric oxide (NO) is an essential signaling molecule present in most living organisms including bacteria, fungi, plants, and animals. NO participates in a wide range of biological processes including vasomotor tone, neurotransmission, and immune response. However, NO is highly reactive and can give rise to reactive nitrogen and oxygen species that, in turn, can modify a broad range of biomolecules. Much evidence supports the critical role of NO in the virulence and replication of viruses, bacteria, protozoan, metazoan, and fungi, thus representing a general mechanism of host defense. However, pathogens have developed different mechanisms to elude the host NO and to protect themselves against oxidative and nitrosative stress. Here, the strategies evolved by viruses, bacteria, protozoan, metazoan, and fungi to escape from the NO-based host defense are overviewed.

Efficacy and Safety of Topical Nitric Oxide-Releasing Berdazimer Gel in Patients With Molluscum Contagiosum: A Phase 3 Randomized Clinical Trial

Importance

Molluscum contagiosum (MC) is a highly contagious skin condition. Lesions may persist for months to years, and no US Food and Drug Administration-approved medications are currently available in the US.

Objective

To assess the efficacy and safety of berdazimer gel, 10.3%, a novel topical nitric oxide-releasing medication, in the treatment of MC.

Design, Setting, and Participants

This was a multicenter, vehicle-controlled, double-blind, phase 3 randomized clinical trial (B-SIMPLE4) conducted in 55 clinics (mostly dermatology and pediatric) in the US from September 1, 2020, to July 21, 2021. Eligible participants were 6 months or older and had from 3 to 70 raised MC lesions. Patients with sexually transmitted MC or with MC only in the periocular area were excluded.

Interventions

Patients were randomized to treatment with berdazimer gel, 10.3%, or vehicle gel, applied as a thin layer to all lesions once daily for 12 weeks.

Main Outcomes and Measures

The primary efficacy end point was complete clearance of all MC lesions at week 12. Safety and tolerability measures included adverse event frequency and severity, and assessment of local skin reactions and scarring. Data analyses were performed from August 31, 2021, to September 14, 2021.

Results

A total of 891 participants were randomized, 444 to berdazimer, 10.3% (mean [range] age, 6.6 [0.9-47.5] years; 228 [51.4%] male; 387 [87.2%] White individuals), and 447 to vehicle (mean [range] age, 6.5 [1.3-49.0] years; 234 [52.3%] female; 382 [85.5%] White individuals). In the intention-to-treat population, 88.5% (393 patients) in the berdazimer group and 88.8% (397 patients) in the vehicle group had a lesion count performed at week 12. At week 12, 32.4% (144 patients) in the berdazimer group achieved complete clearance of MC lesions compared with 19.7% (88 patients) in the vehicle group (absolute difference, 12.7%; odds ratio, 2.0; 95% CI, 1.5-2.8; P < .001) with 14.4% (64 patients) of the berdazimer group discontinuing treatment because of MC clearance compared with 8.9% (40 patients) of the vehicle group. Adverse event rates were low. The most common adverse events were application-site pain and erythema, mostly mild in severity. Adverse events leading to discontinuation affected 4.1% (18 patients) of the berdazimer group and 0.7% (3 patients) of the vehicle group. The most common local skin reaction was mild to moderate erythema.

Conclusions and Relevance

Use of berdazimer gel, 10.3%, for MC appears to demonstrate favorable efficacy and safety with low adverse event rates.

Trial Registration

ClinicalTrials.gov Identifier: NCT04535531.

NO in Viral Infections: Role and Development of Antiviral Therapies

Nitric oxide is a ubiquitous signaling radical that influences critical body functions. Its importance in the cardiovascular system and the innate immune response to bacterial and viral infections has been extensively investigated. The overproduction of NO is an early component of viral infections, including those affecting the respiratory tract. The production of high levels of NO is due to the overexpression of NO biosynthesis by inducible NO synthase (iNOS), which is involved in viral clearance. The development of NO-based antiviral therapies, particularly gaseous NO inhalation and NO-donors, has proven to be an excellent antiviral therapeutic strategy. The aim of this review is to systematically examine the multiple research studies that have been carried out to elucidate the role of NO in viral infections and to comprehensively describe the NO-based antiviral strategies that have been developed thus far. Particular attention has been paid to the potential mechanisms of NO and its clinical use in the prevention and therapy of COVID-19.

SB206, a Nitric Oxide-Releasing Topical Medication, Induces the Beginning of the End Sign and Molluscum Clearance

The beginning of the end (BOTE) sign has been proposed to describe well-recognized clinical signs of inflammation (including erythema, induration, and scale) that predict imminent resolution of molluscum contagiosum (MC). This phenomenon has never been prospectively studied. An integrated analysis of two prospective, 12-week, randomized, double-blind clinical trials of topical nitric oxide–releasing SB206 gel evaluated an association between BOTE sign and MC lesion reduction. Of 707 randomized patients, ~80% exhibited BOTE signs regardless of treatment assignment. At week 12, MC lesion counts decreased from baseline by 50.7% for baseline BOTE+ versus 29.1% for BOTE– (P = 0.0015) vehicle-treated patients compared with a 63.3% decrease for baseline BOTE+ versus 51.7% for BOTE– (P = 0.0194) SB206-treated patients. Among vehicle-treated patients, 48 (22.3%) who were never BOTE+ had an 18.5% reduction from baseline in MC lesion counts versus a 34.0% reduction in 165 patients (76.7%) who experienced BOTE at any time, suggesting that the projected duration of lesion clearance for patients with 18–20 MC lesions is 15 months for BOTE– versus 6 months for BOTE+ patients. Patients who were both BOTE+ and treated with SB206 had the greatest reduction in MC lesion count. SB206 may trigger BOTE signs and shorten the duration of MC infection. The two studies whose data are analyzed in this study are registered at ClinicalTrials.gov with the identifiers NCT03927703 and NCT03927716

The potential role of inhaled nitric oxide for postexposure chemoprophylaxis of COVID-19

Background

Several vaccines have been fast-tracked in an attempt to decrease the morbidity and mortality of COVID-19. However, post-exposure prophylaxis has been overlooked in battling COVID-19.

Main text

Inhaled nitric oxide is a potential tool in post-exposure prophylaxis of COVID-19. It decreases cytosolic calcium levels, which impairs the action of Furin. SARS-CoV-2 uses Furin to replicate in the respiratory tract.

Short conclusion

Inhaled nitric oxide could decrease the viral load in the upper respiratory tract, abort clinically symptomatic infection, and prevent subsequent complications. Nitric oxide might be a tool for post-exposure chemoprophylaxis in at-risk groups, especially medical personnel.

Management of Difficult-to-Treat Warts: Traditional and New Approaches

Warts are regularly treated by dermatologists, and while many respond readily to first-line treatments, others may represent a therapeutic challenge. Large, deep, numerous, and extensive warts; treatment-resistant lesions with higher risk for side effects, such as hypopigmentation; or patients unable to tolerate or comply with our treatment regimen, may need alternative treatment options. In this work we review the characteristics of select modalities that should be considered for difficult-to-treat warts. We discuss efficacy and tolerability data as well as practical features that can guide us to select the best treatment for every scenario. Novel approaches, still in an investigational phase, are also discussed to illustrate potential future directions of wart treatment.

Nitric oxide and viral infection: Recent developments in antiviral therapies and platforms

Nitric oxide (NO) is a gasotransmitter of great significance to developing the innate immune response to many bacterial and viral infections, while also modulating vascular physiology. The generation of NO from the upregulation of endogenous nitric oxide synthases serves as an efficacious method for inhibiting viral replication in host defense and warrants investigation for the development of antiviral therapeutics. With increased incidence of global pandemics concerning several respiratory-based viral infections, it is necessary to develop broad therapeutic platforms for inhibiting viral replication and enabling more efficient host clearance, as well as to fabricate new materials for deterring viral transmission from medical devices. Recent developments in creating stabilized NO donor compounds and their incorporation into macromolecular scaffolds and polymeric substrates has created a new paradigm for developing NO-based therapeutics for long-term NO release in applications for bactericidal and blood-contacting surfaces. Despite this abundance of research, there has been little consideration of NO-releasing scaffolds and substrates for reducing passive transmission of viral infections or for treating several respiratory viral infections. The aim of this review is to highlight the recent advances in developing gaseous NO, NO prodrugs, and NO donor compounds for antiviral therapies; discuss the limitations of NO as an antiviral agent; and outline future prospects for guiding materials design of a next generation of NO-releasing antiviral platforms.

Synthetic, Natural, and Semisynthetic Polymer Carriers for Controlled Nitric Oxide Release in Dermal Applications: A Review

Nitric oxide (NO•) is a free radical gas, produced in the human body to regulate physiological processes, such as inflammatory and immune responses. It is required for skin health; therefore, a lack of NO• is known to cause or worsen skin conditions related to three biomedical applications- infection treatment, injury healing, and blood circulation. Therefore, research on its topical release has been increasing for the last two decades. The storage and delivery of nitric oxide in physiological conditions to compensate for its deficiency is achieved through pharmacological compounds called NO-donors. These are further incorporated into scaffolds to enhance therapeutic treatment. A wide range of polymeric scaffolds has been developed and tested for this purpose. Hence, this review aims to give a detailed overview of the natural, synthetic, and semisynthetic polymeric matrices that have been evaluated for antimicrobial, wound healing, and circulatory dermal applications. These matrices have already set a solid foundation in nitric oxide release and their future perspective is headed toward an enhanced controlled release by novel functionalized semisynthetic polymer carriers and co-delivery synergetic platforms. Finally, further clinical tests on patients with the targeted condition will hopefully enable the eventual commercialization of these systems.

Targeting DNA Damage Response as a Strategy to Treat HPV Infections

Mucosotropic human papillomaviruses (HPVs) cause prevalent anogenital infections, some of which can progress to cancers. It is imperative to identify efficacious drug candidates, as there are few therapeutic options. We have recapitulated a robust productive program of HPV-18 in organotypic raft cultures of primary human keratinocytes. The HPV E7 protein induces S phase reentry, along with DNA damage response (DDR) in differentiated cells to support viral DNA amplification. A number of small molecule inhibitors of DDR regulators are in clinical use or clinical trials to treat cancers. Here, we used our raft culture system to examine effects of inhibitors of ATR/Chk1 and ATM/Chk2 on HPV infection. The inhibitors impaired S-phase reentry and progression as well as HPV DNA amplification. The Chk1 inhibitor MK-8776 was most effective, reducing viral DNA amplification by 90-99% and caused DNA damage and apoptosis, preferentially in HPV infected cells. We found that this sensitivity was imparted by the E7 protein and report that MK-8776 also caused extensive cell death of cervical cancer cell lines. Furthermore, it sensitized the cells to cisplatin, commonly used to treat advanced cervical cancer. Based on these observations, the Chk1 inhibitors could be potential effective agents to be re-purposed to treat the spectrum of HPV infections in single or combination therapy.