Summary Vasculopathies caused by varicella zoster virus (VZV) are indicative of a productive virus infection in cerebral arteries after either reactivation of VZV (shingles) or primary infection ...(chickenpox). VZV vasculopathy can cause ischaemic infarction of the brain and spinal cord, as well as aneurysm, subarachnoid and cerebral haemorrhage, carotid dissection, and, rarely, peripheral arterial disease. VZV vasculopathy in immunocompetent or immunocompromised individuals can be unifocal or multifocal with deep-seated and superficial infarctions. Lesions at the grey–white matter junction on brain imaging are a clue to diagnosis. Involvement of both large and small arteries is more common than that of either alone. Most patients have a mononuclear cerebrospinal fluid pleocytosis, often with red blood cells. Cerebrospinal fluid pleocytosis and rash are absent in about a third of cases. Anti-VZV IgG antibody in the cerebrospinal fluid is found more frequently than VZV DNA. In recent years, the number of recognised VZV vasculopathies has grown, and accurate diagnosis is important for the effective treatment of these disorders.
Varicella-zoster virus (VZV) is a human herpes virus which causes varicella (chicken pox) as a primary infection, and, following a variable period of latency in neurons in the peripheral ganglia, may ...reactivate to cause herpes zoster (shingles) as well as a variety of neurological syndromes. In this overview we consider some recent issues in alphaherpesvirus latency with special focus on VZV ganglionic latency. A key question is the nature and extent of viral gene transcription during viral latency. While it is known that this is highly restricted, it is only recently that the very high degree of that restriction has been clarified, with both VZV gene 63-encoded transcripts and discovery of a novel VZV transcript (VLT) that maps antisense to the viral transactivator gene 61. It has also emerged in recent years that there is significant epigenetic regulation of VZV gene transcription, and the mechanisms underlying this are complex and being unraveled. The last few years has also seen an increased interest in the immunological aspects of VZV latency and reactivation, in particular from the perspective of inborn errors of host immunity that predispose to different VZV reactivation syndromes.
Herpes simplex virus type 1 (HSV-1; human herpesvirus 1) and varicella-zoster virus (VZV; human herpesvirus 3) are human neurotropic alphaherpesviruses that cause lifelong infections in ganglia. ...Following primary infection and establishment of latency, HSV-1 reactivation typically results in herpes labialis (cold sores), but can occur frequently elsewhere on the body at the site of primary infection (e.g. whitlow), particularly at the genitals. Rarely, HSV-1 reactivation can cause encephalitis; however, a third of the cases of HSV-1 encephalitis are associated with HSV-1 primary infection. Primary VZV infection causes varicella (chickenpox) following which latent virus may reactivate decades later to produce herpes zoster (shingles), as well as an increasingly recognized number of subacute, acute and chronic neurological conditions. Following primary infection, both viruses establish a latent infection in neuronal cells in human peripheral ganglia. However, the detailed mechanisms of viral latency and reactivation have yet to be unravelled. In both cases latent viral DNA exists in an 'end-less' state where the ends of the virus genome are joined to form structures consistent with unit length episomes and concatemers, from which viral gene transcription is restricted. In latently infected ganglia, the most abundantly detected HSV-1 RNAs are the spliced products originating from the primary latency associated transcript (LAT). This primary LAT is an 8.3 kb unstable transcript from which two stable (1.5 and 2.0 kb) introns are spliced. Transcripts mapping to 12 VZV genes have been detected in human ganglia removed at autopsy; however, it is difficult to ascribe these as transcripts present during latent infection as early-stage virus reactivation may have transpired in the post-mortem time period in the ganglia. Nonetheless, low-level transcription of VZV ORF63 has been repeatedly detected in multiple ganglia removed as close to death as possible. There is increasing evidence that HSV-1 and VZV latency is epigenetically regulated. In vitro models that permit pathway analysis and identification of both epigenetic modulations and global transcriptional mechanisms of HSV-1 and VZV latency hold much promise for our future understanding in this complex area. This review summarizes the molecular biology of HSV-1 and VZV latency and reactivation, and also presents future directions for study.
Varicella zoster virus (VZV) is an exclusively human neurotropic alphaherpesvirus. Primary infection causes varicella (chickenpox), after which virus becomes latent in cranial nerve ganglia, dorsal ...root ganglia, and autonomic ganglia along the entire neuraxis. Years later, in association with a decline in cell-mediated immunity in elderly and immunocompromised individuals, VZV reactivates and causes a wide range of neurologic disease. This article discusses the clinical manifestations, treatment, and prevention of VZV infection and reactivation; pathogenesis of VZV infection; and current research focusing on VZV latency, reactivation, and animal models.
Varicella-zoster virus (VZV), an alphaherpesvirus, establishes lifelong latent infection in the neurons of >90% humans worldwide, reactivating in one-third to cause shingles, debilitating pain and ...stroke. How VZV maintains latency remains unclear. Here, using ultra-deep virus-enriched RNA sequencing of latently infected human trigeminal ganglia (TG), we demonstrate the consistent expression of a spliced VZV mRNA, antisense to VZV open reading frame 61 (ORF61). The spliced VZV latency-associated transcript (VLT) is expressed in human TG neurons and encodes a protein with late kinetics in productively infected cells in vitro and in shingles skin lesions. Whereas multiple alternatively spliced VLT isoforms (VLT
) are expressed during lytic infection, a single unique VLT isoform, which specifically suppresses ORF61 gene expression in co-transfected cells, predominates in latently VZV-infected human TG. The discovery of VLT links VZV with the other better characterized human and animal neurotropic alphaherpesviruses and provides insights into VZV latency.
Sensitization of trigeminal ganglion neurons contributes to primary headache disorders such as migraine, but the specific neuronal and non-neuronal trigeminal subtypes that are involved remain ...unclear. We thus developed a cell atlas in which human and mouse trigeminal ganglia are transcriptionally and epigenomically profiled at single-cell resolution. These data describe evolutionarily conserved and human-specific gene expression patterns within each trigeminal ganglion cell type, as well as the transcription factors and gene regulatory elements that contribute to cell-type-specific gene expression. We then leveraged these data to identify trigeminal ganglion cell types that are implicated both by human genetic variation associated with migraine and two mouse models of headache. This trigeminal ganglion cell atlas improves our understanding of the cell types, genes, and epigenomic features involved in headache pathophysiology and establishes a rich resource of cell-type-specific molecular features to guide the development of more selective treatments for headache and facial pain.
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•A human and mouse trigeminal ganglion (TG) cell atlas•Conservation of cell-type-specific gene expression between human and mouse TG•Epigenomic maps of TG offer insight into migraine-associated genetic variants•Neuronal and non-neuronal cell types are engaged in two mouse headache models
Trigeminal ganglion neurons are activated in migraine and related headache disorders. Yang et al. developed a cell atlas in which human and mouse trigeminal ganglia are transcriptionally and epigenomically profiled at single-cell resolution. These data provide a rich resource for understanding the cell types and genetic mechanisms underlying migraine susceptibility and for developing novel analgesics.
Varicella-zoster virus (VZV) infection causes varicella, after which the virus becomes latent in ganglionic neurons. In tissue culture, VZV-infected human neurons remain viable at 2 weeks, whereas ...fibroblasts develop cytopathology. Next-generation RNA sequencing was used to compare VZV transcriptomes in neurons and fibroblasts and identified only 12 differentially transcribed genes of the 70 annotated VZV open reading frames (ORFs), suggesting that defective virus transcription does not account for the lack of cell death in VZV-infected neurons in vitro.
Varicella–zoster virus is an exclusively human herpesvirus that causes chickenpox (varicella), becomes latent in cranial-nerve and dorsal-root ganglia, and frequently reactivates decades later to ...produce shingles (zoster) and postherpetic neuralgia. In immunocompetent elderly persons or immunocompromised patients, varicella–zoster virus may produce disease of the central nervous system.
Since the last major review of varicella–zoster virus in the
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advances in molecular biology have provided important new insights into the pathogenesis of infection with varicella–zoster virus. The detection of varicella–zoster virus in blood vessels and other tissues by methods based on the polymerase chain reaction (PCR) has widened the recognized . . .
Infection with varicella zoster virus (VZV) causes varicella (chickenpox), which can be severe in immunocompromised individuals, infants and adults. Primary infection is followed by latency in ...ganglionic neurons. During this period, no virus particles are produced and no obvious neuronal damage occurs. Reactivation of the virus leads to virus replication, which causes zoster (shingles) in tissues innervated by the involved neurons, inflammation and cell death - a process that can lead to persistent radicular pain (postherpetic neuralgia). The pathogenesis of postherpetic neuralgia is unknown and it is difficult to treat. Furthermore, other zoster complications can develop, including myelitis, cranial nerve palsies, meningitis, stroke (vasculopathy), retinitis, and gastroenterological infections such as ulcers, pancreatitis and hepatitis. VZV is the only human herpesvirus for which highly effective vaccines are available. After varicella or vaccination, both wild-type and vaccine-type VZV establish latency, and long-term immunity to varicella develops. However, immunity does not protect against reactivation. Thus, two vaccines are used: one to prevent varicella and one to prevent zoster. In this Primer we discuss the pathogenesis, diagnosis, treatment, and prevention of VZV infections, with an emphasis on the molecular events that regulate these diseases. For an illustrated summary of this Primer, visit: http://go.nature.com/14xVI1.
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