The role of dopamine in the modulation of monocyte-induced Th17- and Th1-immune response in multiple sclerosis.

Multiple sclerosis (MS) is a chronic inflammatory demyelinating disease of the central nervous system (CNS) with autoimmune mechanism of development. The investigation of neuroimmune interaction is one of the most developing directions in MS pathogenesis study. Catecholamines are direct mediators of this interaction and can be involved in the pathogenesis of MS by modulating cells of both innate and adaptive immune systems. The aim of this study was to investigate the influence of dopamine and norepinephrine on the ability of monocytes of patients with relapsing-remitting MS, to induce Th17- and Th1-immune response, which play a crucial role in the autoimmunity of the CNS. We found, that both dopamine and norepinephrine modulate the production of Th17- (IL-23, IL-1ß, and IL-6) and Th1-promoting (IL-12p70) cytokines by activated peripheral blood mononuclear cells or CD14+ monocytes in patients with MS and in healthy subjects. We also found the inhibitory effect of dopamine and norepinephrine on monocyte-induced production of IL-17 and IFN-γ by autologous CD4+ T-cells in both groups. Finally, the multidirectional role of D1- and D2-like dopaminergic receptors in the modulatory effect of dopamine on the ability of CD14+ monocytes to activate CD4+ T-cells was established, expanding the potential role of dopamine in the neuroimmune interaction.

New phosphosite-specific antibodies to unravel the role of GRK phosphorylation in dopamine D2 receptor regulation and signaling.

The dopamine D2 receptor (D2R) is the target of drugs used to treat the symptoms of Parkinson's disease and schizophrenia. The D2R is regulated through its interaction with and phosphorylation by G protein receptor kinases (GRKs) and interaction with arrestins. More recently, D2R arrestin-mediated signaling has been shown to have distinct physiological functions to those of G protein signalling. Relatively little is known regarding the patterns of D2R phosphorylation that might control these processes. We aimed to generate antibodies specific for intracellular D2R phosphorylation sites to facilitate the investigation of these mechanisms. We synthesised double phosphorylated peptides corresponding to regions within intracellular loop 3 of the hD2R and used them to raise phosphosite-specific antibodies to capture a broad screen of GRK-mediated phosphorylation. We identify an antibody specific to a GRK2/3 phosphorylation site in intracellular loop 3 of the D2R. We compared measurements of D2R phosphorylation with other measurements of D2R signalling to profile selected D2R agonists including previously described biased agonists. These studies demonstrate the utility of novel phosphosite-specific antibodies to investigate D2R regulation and signalling.

Anti-dopamine D2 receptor antibodies in chronic tic disorders.

AIM: To investigate the association between circulating anti-dopamine D2 receptor (D2R) autoantibodies and the exacerbation of tics in children with chronic tic disorders (CTDs). METHOD: One hundred and thirty-seven children with CTDs (108 males, 29 females; mean age [SD] 10y 0mo [2y 7mo], range 4-16y) were recruited over 18 months. Patients were assessed at baseline, at tic exacerbation, and at 2 months after exacerbation. Serum anti-D2R antibodies were evaluated using a cell-based assay and blinded immunofluorescence microscopy scoring was performed by two raters. The association between visit type and presence of anti-D2R antibodies was measured with McNemar's test and repeated-measure logistic regression models, adjusting for potential demographic and clinical confounders. RESULTS: At exacerbation, 11 (8%) participants became anti-D2R-positive ('early peri-exacerbation seroconverters'), and nine (6.6%) became anti-D2R-positive at post-exacerbation ('late peri-exacerbation seroconverters'). The anti-D2R antibodies were significantly associated with exacerbations when compared to baseline (McNemar's odds ratio=11, p=0.003) and conditional logistic regression confirmed this association (Z=3.49, p<0.001) after adjustment for demographic and clinical data and use of psychotropic drugs. INTERPRETATION: There is a potential association between immune mechanisms and the severity course of tics in adolescents with CTDs.

Assessment of the Association of D2 Dopamine Receptor Gene and Reported Allele Frequencies With Alcohol Use Disorders: A Systematic Review and Meta-analysis.

Importance: The association between the D2 dopamine receptor gene (DRD2) Taq1A locus (rs1800497) and alcohol use disorder (AUD) is enduring but the subject of long-standing controversy; meta-analysis of studies across 3 decades shows an association between rs1800497 and AUD, but genome-wide analyses have detected no role for rs1800497 in any phenotype. No evidence has emerged that rs1800497, which is located in ANKK1, perturbs the expression or function of DRD2. Objective: To resolve contradictions in previous studies by identifying hidden confounders and assaying for functional effects of rs1800497 and other loci in the DRD2 region. Data Sources: PubMed (882 studies), Embase (1056 studies), and Web of Science (501 studies) databases were searched through August 2018. Three clinical populations-Finnish, Native American, and African American participants-were genotyped for 208 to 277 informative single-nucleotide polymorphisms (SNPs) across the DRD2 region to test the associations of SNPs in this region with AUD. Study Selection: Eligible studies had diagnosis of AUD made by accepted criteria, reliable genotyping methods, sufficient genotype data to calculate odds ratios and 95% CIs, and availability of control allele frequencies or genotype frequencies. Data Extraction and Synthesis: After meta-analysis of 62 studies, metaregression was performed to detect between-study heterogeneity and to explore the effects of moderators, including deviations of cases and controls from allele frequencies in large population databases (ExAC and 1000 Genomes). Linkage to AUD and the effect on gene expression of rs1800497 were evaluated in the context of other SNPs in the DRD2 region. Data analysis was performed from August 2018 to March 2019. This study follows the Preferred Reporting Items for Systematic Reviews and Meta-analyses reporting guideline. Main Outcomes and Measures: The effects of rs1800497 and other SNPs in the DRD2 region on gene expression were measured in human postmortem brain samples via differential allelic expression and evaluated in other tissues via publicly available expression quantitative locus data. Results: A total of 62 studies of DRD2 and AUD with 16 294 participants were meta-analyzed. The rs1800497 SNP was associated with AUD (odds ratio, 1.23; 95% CI, 1.14-1.31; P < .001). However, the association was attributable to spuriously low allele frequencies in controls in positive studies, which also accounted for some between-study heterogeneity (I2 = 43%; 95% CI, 23%-58%; Q61 = 107.20). Differential allelic expression of human postmortem brain and analysis of expression quantitative loci in public data revealed that a cis-acting locus or loci perturb the DRD2 transcript level; however, rs1800497 does not and is not in strong disequilibrium with such a locus. Across the DRD2 region, other SNPs are more strongly associated with AUD than rs1800497, although no DRD2 SNP was significantly associated in these 3 clinical samples. Conclusions and Relevance: In this meta-analysis, the significant association of DRD2 with AUD was reassessed. The DRD2 association was attributable to anomalously low control allele frequencies, not function, in positive studies. For genetic studies, statistical replication is not verification.

Akinetic mutism and status epilepticus due to Epstein Barr virus encephalitis.

Neurological complications of Epstein Barr virus (EBV) infection are infrequent and may include occasionally encephalitis, usually with a benign evolution. We here report on an aggressive case of EBV encephalitis in a 14-year-old boy with extensive basal ganglia involvement, and to a lesser degree of brain cortex who presented atypically with akinetic mutism and non-convulsive status epilepticus, requiring intensive care but showed a favorable outcome. EBV encephalitis is uncommon and its best management is unclear. Its pathophysiology is not well understood but could include autoimmunity. Onconeuronal and synaptic antibodies were negative in serum and cerebrospinal fluid, including the dopamine D2 receptor. To the best of our knowledge, this is the first report to evaluate antibodies to D2 receptors in EBV encephalitis. Corticosteroid therapy is usually recommended but the use of acyclovir is controversial. Intensive care is required in severe cases to assure a favorable outcome.

Safety and enhanced immunostimulatory activity of the DRD2 antagonist ONC201 in advanced solid tumor patients with weekly oral administration.

BACKGROUND: ONC201 is a small molecule antagonist of DRD2, a G protein-coupled receptor overexpressed in several malignancies, that has prolonged antitumor efficacy and immunomodulatory properties in preclinical models. The first-in-human trial of ONC201 previously established a recommended phase II dose (RP2D) of 625 mg once every three weeks. Here, we report the results of a phase I study that evaluated the safety, pharmacokinetics (PK), and pharmacodynamics (PD) of weekly ONC201. METHODS: Patients ≥ 18 years old with an advanced solid tumor refractory to standard treatment were enrolled. Dose escalation proceeded with a 3 + 3 design from 375 mg to 625 mg of ONC201. One cycle, also the dose-limiting toxicity (DLT) window, was 21 days. The primary endpoint was to determine the RP2D of weekly ONC201, which was confirmed in an 11-patient dose expansion cohort. RESULTS: Twenty patients were enrolled: three at 375 mg and 17 at 625 mg of ONC201. The RP2D was defined as 625 mg with no DLT, treatment discontinuation, or dose modifications due to drug-related toxicity. PK profiles were consistent with every-three-week dosing and similar between the first and fourth dose. Serum prolactin and caspase-cleaved cytokeratin-18 induction were detected, along with intratumoral integrated stress response activation and infiltration of granzyme B+ Natural Killer cells. Induction of immune cytokines and effectors was higher in patients who received ONC201 once weekly versus once every three weeks. Stable disease of > 6 months was observed in several prostate and endometrial cancer patients. CONCLUSIONS: Weekly, oral ONC201 is well-tolerated and results in enhanced immunostimulatory activity that warrants further investigation. TRIAL REGISTRATION: NCT02250781 (Oral ONC201 in Treating Patients With Advanced Solid Tumors), NCT02324621 (Continuation of Oral ONC201 in Treating Patients With Advanced Solid Tumors).

The influence of immune activation at early vs late gestation on fetal NRG1-ErbB4 expression and behavior in juvenile and adult mice offspring.

Maternal inflammation during pregnancy is associated with a higher incidence of mental disorders (e.g. schizophrenia and autism) in the offspring. In our study, we investigate the involvement of the NRG-ErbB signaling pathway in rodent fetal brains four hours following maternal immune activation (MIA) insult at two different gestational days (i.e. early vs late). Furthermore, we test the long-term behavioral alteration of the exposed MIA mice at juvenile and adulthood. We demonstrate that MIA at late, but not at early gestation day, altered the expression of NRG1, its receptor ErbB4, and the dopamine D2 receptor four hours post injection of viral or bacterial mimic material in fetal brain. At the behavioral levels, adult late-MIA-exposed female offspring, but not juvenile, display lack preference to a novel object. While working memory alteration observed only in adult male MIA-exposed offspring at late gestation day. In addition, we found that adult females MIA-exposed mice spent more time in the center of the open field than female-saline groups. On the other hand, juvenile male offspring exposed to MIA at early, but not late, gestation day displayed a significant alteration in social interaction. Our results suggest that MIA during late gestation immediately influences the expression levels of the NRG1 and ErbB4 genes, and affects long-term behavioral changes at adulthood. These behavioral changes are time related and sex-specific. Thus, immune activation at late stages of the embryonic brain development initiates the activation of the NRG1-ErbB4 pathway and this disturbance might result in cognitive dysfunction in adulthood.

[Autoantibodies Associated with Autoimmune Basal Ganglia Disorders].

Autoimmune basal ganglia disorders (ABGDs) are presumed autoimmune encephalitides characterized by movement disorders and basal ganglia lesions on neuroimaging. The most common type of autoimmune encephalitis manifesting as movement disorders is anti-N-methyl-D-aspartate (NMDA) receptor encephalitis. Anti-phospholipid antibody syndrome and neuropsychiatric lupus may present with chorea or other involuntary movements. In childhood, Sydenham's chorea is an important differential diagnosis. Although autoantibodies directed against the surface antigens on basal ganglia neurons are assumed to cause ABGDs, few autoantibodies have been demonstrated to be relevant to certain clinical syndromes except for anti-NMDA receptor antibodies. However, recent studies have identified autoantibodies to the dopamine D2 receptor and collapsin response mediator proteins in patients with ABGDs. It remains to be elucidated, however, whether these autoantibodies to basal ganglia antigens play pathogenic roles in ABGDs.

Validation of dopamine receptor DRD1 and DRD2 antibodies using receptor deficient mice.

Dopamine receptors 1 and 2 (DRD1, DRD2) are essential for signaling in the brain for a multitude of brain functions. Previous work using several antibodies against these receptors is abundant but only the minority of antibodies used have been validated and, therefore, the results of these studies remain uncertain. Herein, antibodies against DRD1 (Merck Millipore AB1765P, Santa Cruz Biotechnology sc-14001, Sigma Aldrich D2944, Alomone Labs ADR-001) and DRD2 (Abcam ab21218, Merck Millipore AB5084P, Santa Cruz Biotechnology sc-5303) have been tested using western blotting and immunohistochemistry on mouse striatum (wild type and corresponding knock-out mice) and when specific, they were further evaluated on rat and human striatum. Moreover, a DRD1 antibody and a DRD2 antibody that were found specific in our tests were used for immunoprecipitation with subsequent mass spectrometrical identification of the immunoprecipitate. Two out of nine antibodies (anti DRD1 Sigma Aldrich D2944 and anti DRD2 Merck Millipore AB5084P) against the abovementioned dopamine receptors were specific for DRD1 and DRD2 as evaluated by western blotting and immunohistochemistry and the immunoprecipitate indeed contained DRD1 and DRD2 as revealed by mass spectrometry. The observed findings may question the use of so far non-validated antibodies against the abovementioned dopamine receptors. Own observations may be valuable for the interpretation of previous results and the design of future studies using dopamine receptors DRD1 or DRD2.

Pramipexole, a Dopamine D2/D3 Receptor-Preferring Agonist, Prevents Experimental Autoimmune Encephalomyelitis Development in Mice.

Experimental autoimmune encephalomyelitis (EAE) is the most used animal model of multiple sclerosis (MS) for the development of new therapies. Dopamine receptors can modulate EAE and MS development, thus highlighting the potential use of dopaminergic agonists in the treatment of MS, which has been poorly explored. Herein, we hypothesized that pramipexole (PPX), a dopamine D2/D3 receptor-preferring agonist commonly used to treat Parkinson's disease (PD), would be a suitable therapeutic drug for EAE. Thus, we report the effects and the underlying mechanisms of action of PPX in the prevention of EAE. PPX (0.1 and 1 mg/kg) was administered intraperitoneally (i.p.) from day 0 to 40 post-immunization (p.i.). Our results showed that PPX 1 mg/kg prevented EAE development, abolishing EAE signs by blocking neuroinflammatory response, demyelination, and astroglial activation in spinal cord. Moreover, PPX inhibited the production of inflammatory cytokines, such as IL-17, IL-1ß, and TNF-α in peripheral lymphoid tissue. PPX was also able to restore basal levels of a number of EAE-induced effects in spinal cord and striatum, such as reactive oxygen species, glutathione peroxidase, parkin, and α-synuclein (α-syn). Thus, our findings highlight the usefulness of PPX in preventing EAE-induced motor symptoms, possibly by modulating immune cell responses, such as those found in MS and other T helper cell-mediated inflammatory diseases.

Antibodies to surface dopamine-2 receptor and N-methyl-D-aspartate receptor in the first episode of acute psychosis in children.

BACKGROUND: The dopamine and glutamate hypotheses are well known in psychosis. Recently, the detection of autoantibodies against proteins expressed on the surface of cells in the central nervous system has raised the possibility that specific immune-mediated mechanisms may define a biological subgroup within psychosis, although no cohort of a first episode of psychosis in children has been investigated. METHODS: Serum taken during the acute presentation of 43 children with first episode of psychosis and serum from 43 pediatric control subjects was assessed for the presence of immunoglobulin (Ig)G, IgM, or IgA antibodies to dopamine-2 receptor (D2R) and NR1 subunit of the N-methyl-D-aspartate receptor using a flow cytometry live cell-based assay and immunolabeling of murine primary neurons. RESULTS: Using a cutoff of three SD above the control mean, serum antibodies to D2R or NR1 were detected in 8 of 43 psychotic patients but not detected in any of 43 control subjects (p < .001). Positive immunoglobulin binding to D2R was found in 3 of 43 psychosis patients (3 IgG, 1 IgM, 0 IgA) and to N-methyl-D-aspartate receptor in 6 of 43 patients (5 IgG, 1 IgM, 1 IgA). Specificity of antibody was confirmed by immunoaffinity purification and immunoabsorption. Significant differences in antibody binding to live, fixed, and fixed and permeabilized neurons were observed, confirming that only live cells can define surface epitope immunolabeling. CONCLUSIONS: This is the first report of serum antibodies to surface D2R and NR1 in pediatric patients with isolated psychosis, which supports the hypothesis that a subgroup of patients may be immune-mediated.

Prenatal stress-induced increases in placental inflammation and offspring hyperactivity are male-specific and ameliorated by maternal antiinflammatory treatment.

Adverse experiences during gestation such as maternal stress and infection are known risk factors for neurodevelopmental disorders, including schizophrenia, autism, and attention deficit/hyperactivity disorder. The mechanisms by which these distinct exposures may confer similar psychiatric vulnerability remain unclear, although likely involve pathways common to both stress and immune responses at the maternal-fetal interface. We hypothesized that maternal stress-induced activation of immune pathways within the placenta, the sex-specific maternal-fetal intermediary, may contribute to prenatal stress programming effects on the offspring. Therefore, we assessed for markers indicative of stress-induced placental inflammation, and examined the ability of maternal nonsteroidal antiinflammatory drug (NSAID) treatment to ameliorate placental effects and thereby rescue the stress-dysregulation phenotype observed in our established mouse model of early prenatal stress (EPS). As expected, placental gene expression analyses revealed increased levels of immune response genes, including the proinflammatory cytokines IL-6 and IL-1ß, specifically in male placentas. NSAID treatment partially ameliorated these EPS effects. Similarly, in adult offspring, males displayed stress-induced locomotor hyperactivity, a hallmark of dopaminergic dysregulation, which was ameliorated by maternal NSAID treatment. Fitting with these outcomes and supportive of dopamine pathway involvement, expression of dopamine D1 and D2 receptors was altered by EPS in males. These studies support an important interaction between maternal stress and a proinflammatory state in the long-term programming effects of maternal stress.

Herpes simplex encephalitis relapse with chorea is associated with autoantibodies to N-Methyl-D-aspartate receptor or dopamine-2 receptor.

BACKGROUND: Movement disorder relapses after herpes simplex virus 1 (HSV1) encephalitis have been hypothesized to be secondary to postviral autoimmunity. Recently, a proportion of patients with HSV1 encephalitis (HSE) were shown to produce autoantibodies against N-methyl-D-aspartate receptor (NMDAR). METHODS: We measured autoantibodies against NMDAR and dopamine-2 receptor (D2R) expressed at the cell surface in the stored acute serum of 9 children with HSE, 3 of whom had a relapsing course with chorea. RESULTS: The 3 patients with chorea had elevated autoantibodies against NMDAR (n = 1), D2R (n = 1), or both (n = 1), whereas patients without chorea were negative (n = 6). The prospectively identified patient with chorea and NMDAR autoantibodies improved after early treatment with steroids, intravenous immunoglobulin, and cyclophosphamide, with reduction in serum NMDAR antibody titers. CONCLUSIONS: These autoantibody findings lend support to the autoimmune hypothesis and the early use of immune suppression in post-HSE chorea.

High-throughput flow cytometry cell-based assay to detect antibodies to N-methyl-D-aspartate receptor or dopamine-2 receptor in human serum.

Over the recent years, antibodies against surface and conformational proteins involved in neurotransmission have been detected in autoimmune CNS diseases in children and adults. These antibodies have been used to guide diagnosis and treatment. Cell-based assays have improved the detection of antibodies in patient serum. They are based on the surface expression of brain antigens on eukaryotic cells, which are then incubated with diluted patient sera followed by fluorochrome-conjugated secondary antibodies. After washing, secondary antibody binding is then analyzed by flow cytometry. Our group has developed a high-throughput flow cytometry live cell-based assay to reliably detect antibodies against specific neurotransmitter receptors. This flow cytometry method is straight forward, quantitative, efficient, and the use of a high-throughput sampler system allows for large patient cohorts to be easily assayed in a short space of time. Additionally, this cell-based assay can be easily adapted to detect antibodies to many different antigenic targets, both from the central nervous system and periphery. Discovering additional novel antibody biomarkers will enable prompt and accurate diagnosis and improve treatment of immune-mediated disorders.

Anti-streptococcal, tubulin, and dopamine receptor 2 antibodies in children with PANDAS and Tourette syndrome: single-point and longitudinal assessments.

Single-point-in-time ELISA optical densities for three putative antibodies identified in Sydenham's chorea, the streptococcal group A carbohydrate antigen, N-acetyl-beta-d-glucosamine, tubulin, and the dopamine 2 receptor, showed no differences in children with PANDAS (n=44) or Tourette syndrome (n=40) as compared to controls (n=24). Anti-tubulin and D2 receptor antibodies assessed in serial samples from 12 PANDAS subjects obtained prior to a documented exacerbation, during the exacerbation (with or without a temporally associated streptococcal infection), and following the exacerbation, showed no evidence of antibody levels correlating with a clinical exacerbation. These data do not support hypotheses suggesting an autoimmune hypothesis in either TS or PANDAS.

Dopamine receptor autoantibodies correlate with symptoms in Sydenham's chorea.

BACKGROUND: Sydenham chorea (SC), a neuropsychiatric sequela of group-A streptococcal infection, is associated with basal ganglia autoantibodies. Although autoantibodies have been proposed in neuropsychiatric disorders, little evidence has been shown to link autoimmunity and clinical symptoms. We hypothesized that dopamine receptor-autoantibody interactions may be the basis of neuropsychiatric symptoms in SC. METHODS: Sera from 22 children with SC (age 10.7±4.5 years) and 22 age-matched controls were studied. Clinical neuropsychiatric symptoms were measured in SC at sample collection using the UFMG-Sydenham's-Chorea-Rating-Scale (USCRS). Anti-dopamine D1 receptor (D1R) and anti-dopamine D2 receptor (D2R) autoantibodies were measured by the enzyme linked immunosorbent assay (ELISA) and were correlated with clinical symptoms. RESULTS: Anti-D1R and anti-D2R autoantibodies were significantly higher in SC compared to controls (n = 44; p = 0.010 and p = 0.017, respectively). We found that the ratio (anti-D2R/D1R) of the two anti-dopaminergic receptor antibodies correlated with neuropsychiatric symptoms as determined by USCRS measurements (n = 18; r = 0.53, p = 0.024). In addition, anti-D2R titers correlated with antistreptolysin-O titers (n = 43; r = 0.49, p = 0.0008). INTERPRETATION: Our report linked, for the first time, autoimmunity with neuropsychiatric symptoms. The significant correlation was found using ratios of autoantibodies against dopamine receptors (anti-D2R/D1R) rather than the absolute elevated individual anti-D1R or anti-D2R titers. We suggest that autoantibodies may lead to a receptor imbalance and induce greater sensitivity to dopamine signaling potentially leading to neuropsychiatric symptoms in SC. Our novel findings suggesting altered balance in the dopaminergic system may provide a new approach in understanding autoimmune neuropsychiatric disorders with possible implications for diagnosis and treatment.