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

Abstract

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.

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

“…The dose-dependent extraordinary antiviral efficacy of amantadine was further demonstrated in that the in vitro medium dose of amantadine (0.4 μg/mL) which abrogated the above tested human BDV-1 strain by 4 weeks, corresponded to the in vivo blood level resulting from the dose of 200 mg orally per day applied in patients of the here described trial. Notably, the non-natural laboratory strain V was insensitive up to the highest in vitro dose of 1.2 μg/mL (Additional file 7: Figure S4), a finding consistent with the significant biological differences of these two strains [22,23].…”

“…In contrast, laboratory-adapted str. V [14] was insensitive to amantadine treatment up to the highest dose of 1.2 μg/ mL (3 μM), consistent with largely different biological properties of natural and non-natural strains [22,23]. It should be noted that the remarkable insensitivity of BDV-1 laboratory strains observed earlier by different researchers [75][76][77], had quite a while led to a general questioning of amantadine's anti-BDV efficacy.…”

“…Two provocative hypotheses contested since two decades were combined, namely whether depression could be linked to infection with a putatively moodmodulating virus (BDV-1) [14][15][16][17], and whether antiviral capacity of a well-known drug (amantadine) with yet ambiguous modes of action [5] could work as safe and well-tolerated antidepressant in infected patients. Testing an infectious contribution of BDV-1 to mental health, particularly depression, meant to be on a rocky path from the start, because human infection was doubted [25], despite evidence at different levels [20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38]. Recently, human BDV-1 infection became an incontrovertible fact by reports on its ability to even cause fatalities [18,19], emphasizing the broad capacity of BDV-1 as a human pathogen.…”

“…Virus infectious units were expressed as focus forming units (FFU) per mL as already mentioned, providing that one infectious unit causes one focus (20-50 antigencarrying cells) which can be visualized by a focus immunoassay (cell ELISA) [46]. The efficacy of amantadine to inhibit replication was analysed in accord to dose and time, comparing two strains of different origin and biology [22,23].…”

“…The "mood virus hypothesis" of depression is supported but as yet not confirmed by linking unique BDV properties with lines of evidence from human infection [15][16][17], namely virus isolates and infection prevalence. Human viruses recovered from psychiatric patients' peripheral blood mononuclear cells cells (PBMCs) [20] and brain [21], were proven to be authentic through marked biological differences to animal viruses [22,23], despite close genetic relationship [24]. Their acknowledgement was, however, constrained by misconception [25].…”