Word recognition memory and serum levels of Borna disease virus specific circulating immune complexes in obsessive-compulsive disorder.

BACKGROUND: Borna disease virus 1 (BoDV-1) is a non-segmented, negative-strand RNA virus that persistently infects mammals including humans. BoDV-1 worldwide occurring strains display highly conserved genomes with overlapping genetic signatures between those of either human or animal origin. BoDV-1 infection may cause behavioral and cognitive disturbances in animals but has also been found in human major depression and obsessive-compulsive disorder (OCD). However, the impact of BoDV-1 on memory functions in OCD is unknown. METHOD: To evaluate the cognitive impact of BoDV-1 in OCD, event-related brain potentials (ERPs) were recorded in a continuous word recognition paradigm in OCD patients (n = 16) and in healthy controls (n = 12). According to the presence of BoDV-1-specific circulating immune complexes (CIC), they were divided into two groups, namely group H (high) and L (low), n = 8 each. Typically, ERPs to repeated items are characterized by more positive waveforms beginning approximately 250 ms post-stimulus. This "old/new effect" has been shown to be relevant for memory processing. The early old/new effect (ca. 300-500 ms) with a frontal distribution is proposed to be a neural correlate of familiarity-based recognition. The late old/new effect (post-500 ms) is supposed to reflect memory recollection processes. RESULTS: OCD patients were reported to show a normal early old/new effect and a reduced late old/new effect compared to normal controls. In our study, OCD patients with a high virus load (group H) displayed exactly these effects, while patients with a low virus load (group L) did not differ from healthy controls. CONCLUSION: These results confirmed that OCD patients had impaired memory recollection processes compared to the normal controls which may to some extent be related to their BoDV-1 infection.

Molecular epidemiology of human Borna disease virus 1 infection revisited.

Borna disease virus 1 (BoDV-1) strains attracted public interest by recently reported rare fatal encephalitis cases in Germany. Previously, human BoDV-1 infection was suggested to contribute to psychiatric diseases. Clinical outcomes (encephalitis vs. psychiatric disease) and epidemiology (zoonotic vs. human-to-human transmission) are still controversial. Here, phylogenetic analyses of 18 human and 4 laboratory strains revealed close genomic homologies both in distant geographical regions, and different clinical entities. Single unique amino acid mutations substantiated the authenticity of human strains. No matching was found with those of shrew strains in the same cluster 4, arguing against zoonosis. Opposite epidemiology concepts should be equally considered.

Prominent Efficacy of Amantadine against Human Borna Disease Virus Infection In Vitro and In Vivo. Comment on Fink et al. Amantadine Inhibits SARS-CoV-2 In Vitro. Viruses 2021, 13, 539.

Amantadine (1-amino-adamantane) is a versatile antiviral compound which has been licensed for decades against influenza viruses. During the Corona pandemic, its effect to inhibit SARS-CoV-2 in vitro has been investigated. However, an in vivo oral inapplicability was concluded due to ID50 doses exceeding eight times the estimated maximum tolerable plasma levels reached by 600 mg orally daily. In contrast, amantadine has been shown to be extraordinarily efficient against human neurotropic Borna disease virus (BoDV-1), presenting with both anti-depressive and anti-viral efficacy against a placebo, achieved by a well-tolerated low oral daily dose of 200 mg amantadine.

Obesity induced by Borna disease virus in rats: key roles of hypothalamic fast-acting neurotransmitters and inflammatory infiltrates.

Human obesity epidemic is increasing worldwide with major adverse consequences on health. Among other possible causes, the hypothesis of an infectious contribution is worth it to be considered. Here, we report on an animal model of virus-induced obesity which might help to better understand underlying processes in human obesity. Eighty Wistar rats, between 30 and 60 days of age, were intracerebrally inoculated with Borna disease virus (BDV-1), a neurotropic negative-strand RNA virus infecting an unusually broad host spectrum including humans. Half of the rats developed fatal encephalitis, while the other half, after 3-4 months, continuously gained weight. At tripled weights, rats were sacrificed by trans-cardial fixative perfusion. Neuropathology revealed prevailing inflammatory infiltrates in the median eminence (ME), progressive degeneration of neurons of the paraventricular nucleus, the entorhinal cortex and the amygdala, and a strikingly high-grade involution of the hippocampus with hydrocephalus. Immune histology revealed that major BDV-1 antigens were preferentially present at glutamatergic receptor sites, while GABAergic areas remained free from BDV-1. Virus-induced suppression of the glutamatergic system caused GABAergic predominance. In the hypothalamus, this shifted the energy balance to the anabolic appetite-stimulating side governed by GABA, allowing for excessive fat accumulation in obese rats. Furthermore, inflammatory infiltrates in the ME and ventro-medial arcuate nucleus hindered free access of appetite-suppressing hormones leptin and insulin. The hormone transport system in hypothalamic areas outside the ME became blocked by excessively produced leptin, leading to leptin resistance. The resulting hyperleptinemic milieu combined with suppressed glutamatergic mechanisms was a characteristic feature of the found metabolic pathology. In conclusion, the study provided clear evidence that BDV-1 induced obesity in the rat model is the result of interdependent structural and functional metabolic changes. They can be explained by an immunologically induced hypothalamic microcirculation-defect, combined with a disturbance of neurotransmitter regulatory systems. The proposed mechanism may also have implications for human health. BDV-1 infection has been frequently found in depressive patients. Independently, comorbidity between depression and obesity has been reported, either. Future studies should address the exciting question of whether BDV-1 infection could be a link, whatsoever, between these two conditions.

Full-length genomic sequencing and characterization of Borna disease virus 1 isolates: Lessons in epidemiology.

Borna disease virus 1 (BoDV-1) is a nonsegmented, negative-strand RNA virus that infects mammals including humans. BoDV-1 strains occur globally, dominate the species Mammalian 1 bornavirus, and display highly conserved genomes and persistent infection (brain, blood). Subclinical infections prevail but the rare fatal outcomes even in people need awareness and risk assessment. Although BoDV-1 strains were successfully isolated, only limited full genomic sequences are available. In this study, the entire genomes of two natural BoDV-1 isolates (Hu-H2, Equ-Cres) and one vaccine strain (DessVac) were sequenced. They were compared with 20 genomes and 20 single-gene sequences (N and P) of worldwide human strains from psychiatric and neurologic patients and animal strains from horses with Borna disease available at GenBank. Phylogenetic analyses confirmed a low divergence not exceeding 5.55%, 5.34%, and 4.94% at the genome, P-gene, and N-gene level, respectively, characteristic of BoDV-1. Human viruses tended to cluster at the country level but appeared to be independent of hosts' diseases and/or time of isolation. Notably, our data also indicated that human viruses provided individual genetic signatures but exhibited no distinct genotypes that separated them from animal strains. Sequence similarities thus occurred between different host species and distant geographic regions, supporting global BoDV-1 prevalence. Overall low genetic divergence among BoDV-1 viruses shown here also argued against zoonotic concepts, requiring further clarification beyond sequence similarities. Finally, unlike shared sequence conservation, phenotyping of natural and laboratory variants revealed that they manipulated host cells differently, underpinning the authenticity of the human BoDV-1 strains.

Antiviral treatment perspective against Borna disease virus 1 infection in major depression: a double-blind placebo-controlled randomized clinical trial.

BACKGROUND: Whether Borna disease virus (BDV-1) is a human pathogen remained controversial until recent encephalitis cases showed BDV-1 infection could even be deadly. This called to mind previous evidence for an infectious contribution of BDV-1 to mental disorders. Pilot open trials suggested that BDV-1 infected depressed patients benefitted from antiviral therapy with a licensed drug (amantadine) which also tested sensitive in vitro. Here, we designed a double-blind placebo-controlled randomized clinical trial (RCT) which cross-linked depression and BDV-1 infection, addressing both the antidepressant and antiviral efficacy of amantadine. METHODS: The interventional phase II RCT (two 7-weeks-treatment periods and a 12-months follow-up) at the Hannover Medical School (MHH), Germany, assigned currently depressed BDV-1 infected patients with either major depression (MD; N = 23) or bipolar disorder (BD; N = 13) to amantadine sulphate (PK-Merz®; twice 100 mg orally daily) or placebo treatment, and contrariwise, respectively. Clinical changes were assessed every 2-3 weeks by the 21-item Hamilton rating scale for depression (HAMD) (total, single, and combined scores). BDV-1 activity was determined accordingly in blood plasma by enzyme immune assays for antigens (PAG), antibodies (AB) and circulating immune complexes (CIC). RESULTS: Primary outcomes (≥25% HAMD reduction, week 7) were 81.3% amantadine vs. 35.3% placebo responder (p = 0.003), a large clinical effect size (ES; Cohen's d) of 1.046, and excellent drug tolerance. Amantadine was safe reducing suicidal behaviour in the first 2 weeks. Pre-treatment maximum infection levels were predictive of clinical improvement (AB, p = 0.001; PAG, p = 0.026; HAMD week 7). Respective PAG and CIC levels correlated with AB reduction (p = 0,001 and p = 0.034, respectively). Follow-up benefits (12 months) correlated with dropped cumulative infection measures over time (p < 0.001). In vitro, amantadine concentrations as low as 2.4-10 ng/mL (50% infection-inhibitory dose) prevented infection with human BDV Hu-H1, while closely related memantine failed up to 100,000-fold higher concentration (200 µg/mL). CONCLUSIONS: Our findings indicate profound antidepressant efficacy of safe oral amantadine treatment, paralleling antiviral effects at various infection levels. This not only supports the paradigm of a link of BDV-1 infection and depression. It provides a novel possibly practice-changing low cost mental health care perspective for depressed BDV-1-infected patients addressing global needs. TRIAL REGISTRATION: The trial was retrospectively registered in the German Clinical Trials Registry on 04th of March 2015. The trial ID is DRKS00007649; https://www.drks.de/drks_web/setLocale_EN.do.

Primary psychosis and Borna disease virus infection in Lithuania: a case control study.

BACKGROUND: The hypothesis that microbial infections may be linked to mental disorders has long been addressed for Borna disease virus (BDV), but clinical and epidemiological evidence remained inconsistent due to non-conformities in detection methods. BDV circulating immune complexes (CIC) were shown to exceed the prevalence of serum antibodies alone and to comparably screen for infection in Europe (DE, CZ, IT), the Middle East (IR) and Asia (CN), still seeking general acceptance. METHODS: We used CIC and antigen (Ag) tests to investigate BDV infection in Lithuania through a case-control study design comparing in-patients suffering of primary psychosis with blood donors. One hundred and six acutely psychotic in-patients with no physical illness, consecutively admitted to the regional mental hospital, and 98 blood donors from the Blood Donation Centre, Lithuania, were enrolled in the study. The severity of psychosis was assessed twice, prior and after acute antipsychotic therapy, by the Brief Psychiatric Rating Scale (BPRS). BDV-CIC and Ag markers were tested once after therapy was terminated. RESULTS: What we found was a significantly higher prevalence of CIC, indicating a chronic BDV infection, in patients with treated primary psychosis than in blood donor controls (39.6 % vs. 22.4 %, respectively). Free BDV Ag, indicating currently active infection, did not show significant differences among study groups. Higher severity of psychosis prior to treatment was inversely correlated to the presence of BDV Ag (42.6 vs. 34.1 BPRS, respectively; p = 0.022). CONCLUSIONS: The study concluded significantly higher BDV infection rates in psychotic than in healthy Lithuanians, thus supporting similar global trends for other mental disorders. The study raised awareness to consider the integration of BDV infection surveillance in psychiatry research in the future.

GC-MS-Based Metabonomic Profiling Displayed Differing Effects of Borna Disease Virus Natural Strain Hu-H1 and Laboratory Strain V Infection in Rat Cortical Neurons.

Borna disease virus (BDV) persists in the central nervous systems of a wide variety of vertebrates and causes behavioral disorders. Previous studies have revealed that metabolic perturbations are associated with BDV infection. However, the pathophysiological effects of different viral strains remain largely unknown. Rat cortical neurons infected with human strain BDV Hu-H1, laboratory BDV Strain V, and non-infected control (CON) cells were cultured in vitro. At day 12 post-infection, a gas chromatography coupled with mass spectrometry (GC-MS) metabonomic approach was used to differentiate the metabonomic profiles of 35 independent intracellular samples from Hu-H1-infected cells (n = 12), Strain V-infected cells (n = 12), and CON cells (n = 11). Partial least squares discriminant analysis (PLS-DA) was performed to demonstrate discrimination between the three groups. Further statistical testing determined which individual metabolites displayed significant differences between groups. PLS-DA demonstrated that the whole metabolic pattern enabled statistical discrimination between groups. We identified 31 differential metabolites in the Hu-H1 and CON groups (21 decreased and 10 increased in Hu-H1 relative to CON), 35 differential metabolites in the Strain V and CON groups (30 decreased and 5 increased in Strain V relative to CON), and 21 differential metabolites in the Hu-H1 and Strain V groups (8 decreased and 13 increased in Hu-H1 relative to Strain V). Comparative metabonomic profiling revealed divergent perturbations in key energy and amino acid metabolites between natural strain Hu-H1 and laboratory Strain V of BDV. The two BDV strains differentially alter metabolic pathways of rat cortical neurons in vitro. Their systematic classification provides a valuable template for improved BDV strain definition in future studies.

Persistent human Borna disease virus infection modifies the acetylome of human oligodendroglia cells towards higher energy and transporter levels.

BACKGROUND: Borna disease virus (BDV) is a neurotropic RNA virus persistently infecting mammalian hosts including humans. Lysine acetylation (Kac) is a key protein post-translational modification (PTM). The unexpectedly broad regulatory scope of Kac let us to profile the entire acetylome upon BDV infection. METHODS: The acetylome was profiled through stable isotope labeling for cell culture (SILAC)-based quantitative proteomics. The quantifiable proteome was annotated using bioinformatics. RESULTS: We identified and quantified 791 Kac sites in 473 Kac proteins in human BDV Hu-H1-infected and non-infected oligodendroglial (OL) cells. Bioinformatic analysis revealed that BDV infection alters the acetylation of metabolic proteins, membrane-associated proteins and transmembrane transporter activity, and affects the acetylation of several lysine acetyltransferases (KAT). CONCLUSIONS: Upon BDV persistence the OL acetylome is manipulated towards higher energy and transporter levels necessary for shuttling BDV proteins to and from nuclear replication sites.

Health care professionals at risk of infection with Borna disease virus - evidence from a large hospital in China (Chongqing).

BACKGROUND: Human Borna disease virus (BDV) infections have recently been reported in China. BDV causes cognitive and behavioural disturbances in animals. The impact on human mental disorders is subject to debate, but previous studies worldwide have found neuropsychiatric patients more frequently infected than healthy controls. A few isolates were recovered from severely depressed patients, but contagiousness of BDV strain remains unknown. METHOD: We addressed the risk of infection in health care settings at the first affiliated hospital of Chongqing Medical University (CQMU), located in downtown Chongqing, a megacity in Southwest China. Between February 2012 and March 2013, we enrolled 1529 participants, of whom 534 were outpatients with major depressive disorder (MDD), 615 were hospital personnel, and 380 were healthy controls who underwent a health check. Infection was determined through BDV-specific circulating immune complexes (CIC), RNA, and selective antibodies (blood). RESULTS: One-fifth of the hospital staff (21.8%) were found to be infected (CIC positive), with the highest prevalence among psychiatry and oncology personnel, which is twice as many as were detected in the healthy control group (11.1%), and exceeds the prevalence detected in MDD patients (18.2%). CONCLUSION: BDV circulates unnoticed in hospital settings in China, putting medical staff at risk and warranting clarification of infection modes and introduction of prevention measures.

Borna disease virus (BDV) infection in psychiatric patients and healthy controls in Iran.

BACKGROUND: Borna disease virus (BDV) is an evolutionary old RNA virus, which infects brain and blood cells of humans, their primate ancestors, and other mammals. Human infection has been correlated to mood disorders and schizophrenia, but the impact of BDV on mental-health still remains controversial due to poor methodological and cross-national comparability. METHOD: This first report from the Middle East aimed to determine BDV infection prevalence in Iranian acute psychiatric disorder patients and healthy controls through circulating immune complexes (CIC), antibodies (Ab) and antigen (pAg) in blood plasma using a standardized triple enzyme immune assay (EIA). Samples of 314 subjects (114 psychiatric cases, 69 blood donors, and 131 healthy controls) were assayed and data analyzed quantitatively and qualitatively. RESULTS: CICs revealed a BDV prevalence of one third (29.5%) in healthy Iranian controls (27.5% controls; 33.3% blood donors). In psychiatric patients CIC prevalence was higher than in controls (40.4%) and significantly correlating with bipolar patients exhibiting overt clinical symptoms (p = 0.005, OR = 1.65). CIC values were significantly elevated in bipolar (p = 0.001) and major depressive disorder (p = 0.029) patients as compared to controls, and in females compared to males (p = 0.031). CONCLUSION: This study supports a similarly high prevalence of subclinical human BDV infections in Iran as reported for central Europe, and provides again an indication for the correlation of BDV infection and mood disorders. Further studies should address the morbidity risk for healthy carriers and those with elevated CIC levels, along with gender disparities.

Human borna disease virus infection impacts host proteome and histone lysine acetylation in human oligodendroglia cells.

BACKGROUND: Borna disease virus (BDV) replicates in the nucleus and establishes persistent infections in mammalian hosts. A human BDV strain was used to address the first time, how BDV infection impacts the proteome and histone lysine acetylation (Kac) of human oligodendroglial (OL) cells, thus allowing a better understanding of infection-driven pathophysiology in vitro. METHODS: Proteome and histone lysine acetylation were profiled through stable isotope labeling for cell culture (SILAC)-based quantitative proteomics. The quantifiable proteome was annotated using bioinformatics. Histone acetylation changes were validated by biochemistry assays. RESULTS: Post BDV infection, 4383 quantifiable differential proteins were identified and functionally annotated to metabolism pathways, immune response, DNA replication, DNA repair, and transcriptional regulation. Sixteen of the thirty identified Kac sites in core histones presented altered acetylation levels post infection. CONCLUSIONS: BDV infection using a human strain impacted the whole proteome and histone lysine acetylation in OL cells.

Borna disease virus: evidence of naturally-occurring infection in cats in Australia.

In Europe, Borna disease virus (BDV) infection has been linked with staggering disease. The aim of this study was serological investigation for BDV infection in Australian cats. De-identified sera were obtained from domestic cats presented at various veterinary clinics. BDV antigen levels were measured by a monoclonal antibody-based ELISA. Antibody to BDV measured semiquantitatively by ELISA was detected in 0.8% of cats from South Australia and 3.2% of animals from NSW Confirmatory assays for ELISA positive samples included Western blot and immunofluorescence assay (IFA) with BDV-specific staining. Seven BDV-antigen positive sera (2.4%) were identified in sera from cats from New South Wales (NSW). In blinded testing, amongst a large number of negative results, repeat submissions over a seven-month period from a cat co-infected with Feline Immunodeficiency Virus (FIV) were BDV-antigen positive. Anti-BDV antibody detected in this cat by ELISA was confirmed by Western blot (p24/ p40/p56) and IFA. For 4 other anti-BDV ELISA-positive samples, specific reactions with BDV proteins were observed by Western blot. Ten other anti-BDV ELISA-positive samples were IFA positive. These data provide consistent serological evidence that, while horses in Australia are free of BDV infection, there may be a low rate of BDV infection in cats.

Human Borna disease virus-infection and its therapy in affective disorders.

Patients with affective disorders show an enhanced prevalence of Borna disease virus (BDV)-infection. Furthermore, BDV causes latent infection preferably in limbic central nervous structures and is suggested to be causally related to subtypes of affective disorders, especially with melancholic clinical features or bipolarity. Such a possible link was highlighted by the first report of amantadine showing an antidepressive and an antiviral efficacy against BDV in a patient with a bipolar disorder. This article summarizes clinical studies which followed this first report on the use of amantadine in BDV-infected patients with an affective disorder. A special focus is given on an open clinical study in patients with depression (n = 25), a study in remitted patients with affective disorders (n = 16), and the effect of amantadine on severe hypomanic or moderately manic patients with a bipolar disorder in an on-off-on study. In these studies amantadine reduced clinical symptoms paralleled by a reduction of BDV-infection in depressive patients, it also reduced all three BDV-parameters (BDV-Ab, -AG, and -CICs) in remitted patients, and it even reduced severe hypomania and moderate mania in bipolar patients. These data suggest the existence of an etiopathogenetic link between BDV and subtypes of affective disorders.