Transcriptome sequencing of neurologic diseases associated genes in HHV-6A infected human astrocyte

Exploring New Mechanism of Depression from the Effects of Virus on Nerve Cells

Depression is a common neuropsychiatric disorder with long-term recurrent depressed mood, pain and despair, pessimism and anxiety, and even suicidal tendencies as the main symptoms. Depression usually induces or aggravates the development of other related diseases, such as sleep disorders and endocrine disorders. In today's society, the incidence of depression is increasing worldwide, and its pathogenesis is complex and generally believed to be related to genetic, psychological, environmental, and biological factors. Current studies have shown the key role of glial cells in the development of depression, and it is noteworthy that some recent evidence suggests that the development of depression may be closely related to viral infections, such as SARS-CoV-2, BoDV-1, ZIKV, HIV, and HHV6, which infect the organism and cause some degree of glial cells, such as astrocytes, oligodendrocytes, and microglia. This can affect the transmission of related proteins, neurotransmitters, and cytokines, which in turn leads to neuroinflammation and depression. Based on the close relationship between viruses and depression, this paper provides an in-depth analysis of the new mechanism of virus-induced depression, which is expected to provide a new perspective on the mechanism of depression and a new idea for the diagnosis of depression in the future.

The Role of Human Herpesvirus 6 Infection in Alzheimer’s Disease Pathogenicity—A Theoretical Mosaic

Alzheimer’s disease (AD), a neurodegenerative disorder generally affecting older adults, is the most common form of dementia worldwide. The disease is marked by severe cognitive and psychiatric decline and has dramatic personal and social consequences. Considerable time and resources are dedicated to the pursuit of a better understanding of disease mechanisms; however, the ultimate goal of obtaining a viable treatment option remains elusive. Neurodegenerative disease as an outcome of gene–environment interaction is a notion widely accepted today; a clear understanding of how external factors are involved in disease pathogenesis is missing, however. In the case of AD, significant effort has been invested in the study of viral pathogens and their role in disease mechanisms. The current scoping review focuses on the purported role HHV-6 plays in AD pathogenesis. First, early studies demonstrating evidence of HHV-6 cantonment in either post-mortem AD brain specimens or in peripheral blood samples of living AD patients are reviewed. Next, selected examples of possible mechanisms whereby viral infection can directly or indirectly contribute to AD pathogenesis are presented, such as autophagy dysregulation, the interaction between miR155 and HHV-6, and amyloid-beta as an antimicrobial peptide. Finally, closely related topics such as HHV-6 penetration in the CNS, HHV-6 involvement in neuroinflammation, and a brief discussion on HHV-6 epigenetics are examined.

DR7 encoded by human herpesvirus 6 promotes glioma development and progression

PURPOSE

We previously identified human herpesvirus 6 (HHV-6) infection in the pathogenesis of glioma. Direct repeat (DR)7, encoded by HHV-6, has been reported to possess malignant transforming activity and involved in Hodgkin's lymphoma carcinogenesis. Here, we aimed to determine the role of DR7 in the development and progression of glioma.

PATIENTS AND METHODS

A total of 27 glioma and 30 normal brain tissues were collected for detection of DR7. Glioma cell proliferation, colony formation, cell cycle, migration, invasion and angiogenesis were evaluated by Cell Counting Kit-8 (CCK-8), soft agar, propidium iodide staining, wound healing, Transwell and chick embryo chorioallantoic membrane assays, respectively. The potential mRNA targets of DR7 were determined using mRNA microarray and validated via Western blot and ELISA.

RESULTS

DR7 could be detected in the 13 glioma tissues with a positive rate of 48.15%, but only the 5 normal brain tissues with a lower positive rate of 16.7%. The two strains of cells isolated from glioma tissues were also found to express DR7. CCK-8 and soft agar assays showed enhanced proliferation and colony formation in the cells expressing DR7 which might be in relation to acceleration of the G1/S phase transition by DR7. Further analyses showed that DR7 could promote glioma cell migration, invasion and angiogenesis. Expression profiles identified hundreds of differentially expressed mRNAs, among which P53, extracellular matrix (ECM) fibronectin, integrin receptor ITGβ5 and specific inhibitors of MMPs, tissue inhibitor of MMPs (TIMP)-2 and TIMP-4, were downregulated, whereas ECM-degrading proteinase MMP-3, proinflammatory cytokines IL-1β, IL-6 and IL-8, were upregulated by DR7, respectively.

CONCLUSION

We observed existence of DR7 in the glioma tissues, and overexpression of DR7 could promote glioma cell development and progression, which might be through creating an inflammatory microenvironment and enhancing degradation of ECM.

Hypothesis: Is there a link between the immune response to Human Herpes Virus type 6Α (HHV-6Α) infection and the interaction network (interactome) of the genes encoding the CTSS, PTX3, CHI3L1, Mx1, CXCL16, BIRC3 and BST2 proteins?

Human Herpes Virus type 6 (HHV-6) is a ubiquitous virus consisting of two viral species, HHV-6A and HHV-6B that have been associated with numerous and diverse pathologies. As many other viruses HHV-6 modulates the apoptotic machinery of its host to subvert immune response to infection, yet the exact mechanisms behind this process remain under investigation. The genes encoding the CTSS, PTX3, CHI3L1, Mx1, CXCL16, BIRC3 and BST2 proteins have been linked to HHV-6Α related neurologic diseases whilst also associated with apoptosis. This study aimed at the identification and functional analysis of the gene interaction network (interactome) of CTSS-PTX3-CHI3L1-Mx1-CXCL16-BIRC3-BST2 so as to evaluate the hypothesis of a probable link between the latter and host's immune response to HHV-6A infection.

Viruses and endogenous retroviruses in multiple sclerosis: From correlation to causation

Multiple sclerosis is an immune-mediated disease with an environmental component. According to a long-standing but unproven hypothesis dating to initial descriptions of multiple sclerosis (MS) at the end of the 19th century, viruses are either directly or indirectly implicated in MS pathogenesis. Whether viruses in MS are principally causal or simply contributory remains to be proven, but many viruses or viral elements-predominantly Epstein-Barr virus, human endogenous retroviruses (HERVs) and human herpesvirus 6 (HHV-6) but also less common viruses such as Saffold and measles viruses-are associated with MS. Here, we present an up-to-date and comprehensive review of the main candidate viruses implicated in MS pathogenesis and summarize how these viruses might cause or lead to the hallmark demyelinating and inflammatory lesions of MS. We review data from epidemiological, animal and in vitro studies and in doing so offer a transdisciplinary approach to the topic. We argue that it is crucially important not to interpret "absence of evidence" as "evidence of absence" and that future studies need to focus on distinguishing correlative from causative associations. Progress in the MS-virus field is expected to arise from an increasing body of knowledge on the interplay between viruses and HERVs in MS. Such interactions suggest common HERV-mediated pathways downstream of viral infection that cause both neuroinflammation and neurodegeneration. We also comment on the limitations of existing studies and provide future research directions for the field.