Varicella zoster virus (VZV)-human neuron interaction

A Synergistic Lipid Nanoparticle Encapsulating mRNA Shingles Vaccine Induces Potent Immune Responses and Protects Guinea Pigs from Viral Challenges

Shingles is caused by the reactivation of varicella zoster virus (VZV) and manifests as painful skin rashes. While the recombinant protein-based vaccine proves highly effective, it encounters supply chain challenges due to a shortage of the necessary adjuvant. Messenger RNA (mRNA)-based vaccines can be rapidly produced on a large scale, but their effectiveness relies on efficient delivery and sequence design. Here, an mRNA-based VZV vaccine using a synergistic lipid nanoparticle (Syn-LNP) containing two different ionizable lipids is developed. Syn-LNP shows superior mRNA expression compared to LNPs formulated with either type of ionizable lipid and to a commercialized LNP. After encapsulating VZV glycoprotein E (gE)-encoding mRNA, mgE@Syn-LNP induces robust humoral and cellular immune responses in two strains of mice. The magnitude of these responses is similar to that induced by adjuvanted recombinant gE proteins and significantly higher than that observed with live-attenuated VZV. mgE@Syn-LNP exhibits durable humoral responses for over 7 months without obvious adverse effects. In addition, mgE@Syn-LNP protects vaccinated guinea pigs against live VZV challenges. Preliminary studies on the mRNA antigen design reveal that the removal of glycosylation sites of gE greatly reduces its immune responses. Collectively, Syn-LNP encapsulating gE-encoded mRNA holds great promise as a shingles vaccine.

p38 activation and viral infection

Viruses completely rely on the energy and metabolic systems of host cells for life activities. Viral infections usually lead to cytopathic effects and host diseases. To date, there are still no specific clinical vaccines or drugs against most viral infections. Therefore, understanding the molecular and cellular mechanisms of viral infections is of great significance to prevent and treat viral diseases. A variety of viral infections are related to the p38 MAPK signalling pathway, and p38 is an important host factor in virus-infected cells. Here, we introduce the different signalling pathways of p38 activation and then summarise how different viruses induce p38 phosphorylation. Finally, we provide a general summary of the effect of p38 activation on virus replication. Our review provides integrated data on p38 activation and viral infections and describes the potential application of targeting p38 as an antiviral strategy.

Varicella-Zoster Virus Infection of Neurons Derived from Neural Stem Cells

Varicella-Zoster virus (VZV) is a human herpesvirus that causes varicella (chickenpox) as a primary infection, and, following a variable period of ganglionic latency in neurons, it reactivates to cause herpes zoster (shingles). An analysis of VZV infection in cultures of neural cells, in particular when these have been obtained from induced pluripotent stem cells (iPSCs) or neural stem cells consisting of highly purified neuronal cultures, has revealed much data that may be of neurobiological significance. Early studies of VZV infection of mature cultured neural cells were mainly descriptive, but more recent studies in homogeneous neural stem cell cultures have used both neuronal cell markers and advanced molecular technology. Two general findings from such studies have been that (a) VZV infection of neurons is less severe, based on several criteria, than that observed in human fibroblasts, and (b) VZV infection of neurons does not lead to apoptosis in these cells in contrast to apoptosis observed in fibroblastic cells. Insights gained from such studies in human neural stem cells suggest that a less severe initial lytic infection in neurons, which are resistant to apoptosis, is likely to facilitate a pathological pathway to a latent state of the virus in human ganglia.

Role of Viruses in the Pathogenesis of Multiple Sclerosis

Multiple sclerosis (MS) is an immune inflammatory disease, where the underlying etiological cause remains elusive. Multiple triggering factors have been suggested, including environmental, genetic and gender components. However, underlying infectious triggers to the disease are also suspected. There is an increasing abundance of evidence supporting a viral etiology to MS, including the efficacy of interferon therapy and over-detection of viral antibodies and nucleic acids when compared with healthy patients. Several viruses have been proposed as potential triggering agents, including Epstein-Barr virus, human herpesvirus 6, varicella-zoster virus, cytomegalovirus, John Cunningham virus and human endogenous retroviruses. These viruses are all near ubiquitous and have a high prevalence in adult populations (or in the case of the retroviruses are actually part of the genome). They can establish lifelong infections with periods of reactivation, which may be linked to the relapsing nature of MS. In this review, the evidence for a role for viral infection in MS will be discussed with an emphasis on immune system activation related to MS disease pathogenesis.

Modeling Varicella Zoster Virus Persistence and Reactivation - Closer to Resolving a Perplexing Persistent State

The latent state of the human herpesvirus varicella zoster virus (VZV) has remained enigmatic and controversial. While it is well substantiated that VZV persistence is established in neurons after the primary infection (varicella or chickenpox), we know little of the types of neurons harboring latent virus genomes, if all can potentially reactivate, what exactly drives the reactivation process, and the role of immunity in the control of latency. Viral gene expression during latency has been particularly difficult to resolve, although very recent advances indicate that it is more restrictive than was once thought. We do not yet understand how genes expressed in latency function in the maintenance and reactivation processes. Model systems of latency are needed to pursue these questions. This has been especially challenging for VZV because the development of in vivo models of VZV infection has proven difficult. Given that up to one third of the population will clinically reactivate VZV to develop herpes zoster (shingles) and suffer from its common long term problematic sequelae, there is still a need for both in vivo and in vitro model systems. This review will summarize the evolution of models of VZV persistence and address insights that have arisen from the establishment of new in vitro human neuron culture systems that not only harbor a latent state, but permit experimental reactivation and renewed virus production. These models will be discussed in light of the recent data gleaned from the study of VZV latency in human cadaver ganglia.

Current In Vitro Models to Study Varicella Zoster Virus Latency and Reactivation

Varicella zoster virus (VZV) is a highly prevalent human pathogen that causes varicella (chicken pox) during primary infection and establishes latency in peripheral neurons. Symptomatic reactivation often presents as zoster (shingles), but it has also been linked to life-threatening diseases such as encephalitis, vasculopathy and meningitis. Zoster may be followed by postherpetic neuralgia, neuropathic pain lasting after resolution of the rash. The mechanisms of varicella zoster virus (VZV) latency and reactivation are not well characterized. This is in part due to the human-specific nature of VZV that precludes the use of most animal and animal-derived neuronal models. Recently, in vitro models of VZV latency and reactivation using human neurons derived from stem cells have been established facilitating an understanding of the mechanisms leading to VZV latency and reactivation. From the models, c-Jun N-terminal kinase (JNK), phosphoinositide 3-kinase (PI3K) and nerve growth factor (NGF) have all been implicated as potential modulators of VZV latency/reactivation. Additionally, it was shown that the vaccine-strain of VZV is impaired for reactivation. These models may also aid in the generation of prophylactic and therapeutic strategies to treat VZV-associated pathologies. This review summarizes and analyzes the current human neuronal models used to study VZV latency and reactivation, and provides some strategies for their improvement.

Vaccination in Chronic Kidney Disease

Infections after cardiovascular disease are the second most common cause of death in the chronic kidney disease population. Vaccination is an important component of maintaining health and wellness in patients with kidney disease. There is a changing epidemiologic landscape for several vaccine-preventable illnesses from childhood to adulthood and unfounded public perception of safety concerns. Several mechanisms have been proposed to cause inadequate vaccine protection in this high-risk group with chronic kidney disease. These have led to recent advances in new designs for vaccination strategies in kidney disease. In this article, we discuss the current evidence and recommendations for vaccination in those with kidney disease and needing renal replacement therapy (dialysis and transplant).

Targeted Genome Sequencing Reveals Varicella-Zoster Virus Open Reading Frame 12 Deletion

The neurotropic herpesvirus varicella-zoster virus (VZV) establishes a lifelong latent infection in humans following primary infection. The low abundance of VZV nucleic acids in human neurons has hindered an understanding of the mechanisms that regulate viral gene transcription during latency. To overcome this critical barrier, we optimized a targeted capture protocol to enrich VZV DNA and cDNA prior to whole-genome/transcriptome sequence analysis. Since the VZV genome is remarkably stable, it was surprising to detect that VZV32, a VZV laboratory strain with no discernible growth defect in tissue culture, contained a 2,158-bp deletion in open reading frame (ORF) 12. Consequently, ORF 12 and 13 protein expression was abolished and Akt phosphorylation was inhibited. The discovery of the ORF 12 deletion, revealed through targeted genome sequencing analysis, points to the need to authenticate the VZV genome when the virus is propagated in tissue culture.IMPORTANCE Viruses isolated from clinical samples often undergo genetic modifications when cultured in the laboratory. Historically, VZV is among the most genetically stable herpesviruses, a notion supported by more than 60 complete genome sequences from multiple isolates and following multiple in vitro passages. However, application of enrichment protocols to targeted genome sequencing revealed the unexpected deletion of a significant portion of VZV ORF 12 following propagation in cultured human fibroblast cells. While the enrichment protocol did not introduce bias in either the virus genome or transcriptome, the findings indicate the need for authentication of VZV by sequencing when the virus is propagated in tissue culture.

Serology of Viral Infections and Tuberculosis Screening in an IBD Population Referred to a Tertiary Centre of Southern Italy

Background

With the introduction of more potent immunosuppressive agents in inflammatory bowel disease, prevention of opportunistic infections has become necessary by introducing screening programs. Prevalence of the most important infectious agents may vary in different geographical areas. The aim of our study was to assess the immune status for hepatitis B, varicella, mononucleosis, and cytomegalovirus infection together with the determination of the hepatitis C and tuberculosis status in Southern Italy.

Methods

Prevalence of latent tuberculosis, together with serology of hepatitis B and C, Epstein-Barr virus, varicella zoster, and cytomegalovirus were collected by analysing retrospectively the clinical charts of IBD patients. Data were integrated with demographic and clinical features.

Results

Data from 509 IBD patients divided in two age groups showed a prevalence of HBV infection in nonvaccinated patients of 9%. Seroprotection (HBsAb) in vaccinated IBD patients was lower (p < 0.0001) compared with that in controls. Prevalences of herpesvirus infections fluctuate between 51% (CMV) and 85% (EBV) and 84% (VZV) in younger patients. Latent tuberculosis and hepatitis C infection were found only in patients > 37 years of age.

Conclusions

In younger patients, high susceptibility rates for primary herpesvirus infections should determine the choice of treatment. Loss of HBV seroprotection in already vaccinated patients should be considered for booster vaccination programs.

Herpes Zoster Lesions on Reconstructed Breast Skin: Rare Objective Proof of Reinervation

Blazed up Herpes zoster lesions have been described in very few patients after free and pedicled flap transfer for reconstructive purpose. Although sensory recovery after flap reconstructions has been studied extensively most studies addressed subjective perceptions of sensation. Objective investigations of spontaneous reinervation of free and pedicled flaps are rare. We would like to present a witnessed herpes zoster infection of a latissimus dorsi skin flap 2 years after breast reconstruction.

Successful Treatment of Brachial Plexopathy Due to Herpes Zoster Infection With Intravenous Immunoglobulin

OBJECTIVE

The aim of this study was to report the case of a male patient with Parkinson disease who developed brachial plexopathy (BP) due to varicella-zoster virus, which was successfully treated with human immunoglobulin.

METHOD

We report the case of a 75-year-old male subject with a diagnosis of Parkinson disease who came to our hospital complaining of pain, skin lesions, and strength loss in his right arm during the past 2 months. Physical examination revealed vesicular rash compatible with varicella-zoster virus lesions. Nerve conduction studies and magnetic resonance imaging of the brachial plexus showed inflammatory changes at that level. A trial with oral valacyclovir followed by intravenous methylprednisolone bolus was administered without further response. However, human intravenous immunoglobulin resulted in complete recovery of the symptoms.

CONCLUSIONS

Human immunoglobulin is effective in BP due to zoster infection and must be considered if standard treatment fails. To the best of our knowledge, this is the first report of BP associated to zoster infection successfully treated with intravenous immunoglobulin.

Evaluation of the economic burden of Herpes Zoster (HZ) infection

The main objective of this systematic review was to evaluate the economic burden of Herpes Zoster (HZ) infection.   The review was conducted in accordance with the standards of the "Preferred Reporting Items for Systematic Reviews and Meta-Analyses" guidelines. The following databases were accessed: ISI/Web of Knowledge (WoS), MEDLINE/PubMed, Scopus, ProQuest, the Cochrane Library and EconLit. Specific literature on health economics was also manually inspected. Thirty-three studies were included. The quality of the studies assessed in accordance with the Consolidated Health Economic Evaluation Reporting Standards checklist was good. All studies evaluated direct costs, apart from one which dealt only with indirect costs. Indirect costs were evaluated by 12 studies. The economic burden of HZ has increased over time. HZ management and drug prescriptions generate the highest direct costs. While increasing age, co-morbidities and drug treatment were found to predict higher direct costs, being employed was correlated with higher indirect costs, and thus with the onset age of the disease. Despite some differences among the selected studies, particularly with regard to indirect costs, all concur that HZ is a widespread disease which has a heavy social and economic burden.

Analysis of HSV Viral Reactivation in Explants of Sensory Neurons

As with all Herpesviruses, Herpes simplex virus (HSV) has both a lytic replication phase and a latency-reactivation cycle. During lytic replication, there is an ordered cascade of viral gene expression that leads to the synthesis of infectious viral progeny. In contrast, latency is characterized by the lack of significant lytic gene expression and the absence of infectious virus. Reactivation from latency is characterized by the re-entry of the virus into the lytic replication cycle and the production of recurrent disease. This unit describes the establishment of the mouse sensory neuron model of HSV-1 latency-reactivation as a useful in vivo system for the analysis of mechanisms involved in latency and reactivation. Assays including the determination of viral yields, immunohistochemical/immunofluorescent detection of viral antigens, and mRNA quantitation are used in experiments designed to investigate the network of cellular and viral proteins regulating HSV-1 lytic infection, latency, and reactivation.

A case of meningitis due to varicella zoster virus reactivation in an immunocompetent child

Background

The development of neurological complications due to varicella zoster virus (VZV) reactivation is relatively uncommon, particularly in the case of immunocompetent patients. Only a few cases have been described in the literature, most of which involved adult or elderly patients.

Clinical presentation

Two days after his pediatrician had diagnosed herpes zoster and prescribed oral acyclovir 400 mg three times a day, a 14-year-old boy was admitted to our hospital because of mild fever, severe headache, slowness, drowsiness and vomiting. A cerebrospinal fluid examination was performed and showed an increased protein concentration (95 mg/dL), normal glucose level (48 mg/dL; blood glucose level, 76 mg/dL) and lymphocytic pleocytosis (1,400 lymphocytes/μL), and VZV DNA was detected by means of polymerase chain reaction (1,250 copies/mL). The results of immunological screening for HIV, lymphocyte subpopulation counts, serum immunoglobulin and complement (C3 and C4) levels, vaccine responsiveness and lymphocytes stimulation tests were unremarkable. Acyclovir was administered intravenously at a dose of 10 mg/kg three times a day and continued for 10 days. The therapy was highly effective and the patient’s clinical condition rapidly improved: fever disappeared after two days, and all of the signs and symptoms of neurological involvement after four days. The skin lesions resolved in about one week, and no pain or dysesthesia was ever reported. Given the favourable evolution of the illness, the child was discharged without further therapy after the 10-day treatment. The findings of a magnetic resonance examination immediately after the discontinuation of the antiviral therapy were normal, and a control examination carried out about four weeks later did not find any sign or symptom of disease.

Conclusion

VZV reactivation can also lead to various neurological complications in immunocompetent children. Prompt therapy with acyclovir and the integrity of the immune system are important in conditioning outcome, but other currently unknown factors probably also play a role.