Identification and cloning of a brain autoantigen in neuro-behavioral SLE

Impaired blood-brain barrier in the microbiota-gut-brain axis: Potential role of bipolar susceptibility gene TRANK1

Bipolar disorder (BD) is a common psychiatric illness with high prevalence and disease burden. Accumulating susceptibility genes for BD have been identified in recent years. However, the exact functions of these genes remain largely unknown. Despite its high heritability, gene and environment interaction is commonly accepted as the major contributing factor to BD pathogenesis. Intestine microbiota is increasingly recognized as a critical environmental factor for human health and diseases via the microbiota‐gut‐brain axis. BD individuals showed altered diversity and compositions in the commensal microbiota. In addition to pro‐inflammatory factors, such as interleukin‐6 and tumour necrosis factor‐α, type 1 interferon signalling pathway is also modulated by specific intestinal bacterial strains. Disruption of the microbiota‐gut‐brain axis contributes to peripheral and central nervous system inflammation, which accounts for the BD aetiology. Administration of type 1 interferon can induce the expression of TRANK1, which is associated with elevated circulating biomarkers of the impaired blood‐brain barrier in BD patients. In this review, we focus on the influence of intestine microbiota on the expression of bipolar gene TRANK1 and propose that intestine microbiota‐dependent type 1 interferon signalling is sufficient to induce the over‐expression of TRANK1, consequently causing the compromise of BBB integrity and facilitating the entrance of inflammatory mediators into the brain. Activated neuroinflammation eventually contributes to the occurrence and development of BD. This review provides a new perspective on how gut microbiota participate in the pathogenesis of BD. Future studies are needed to validate these assumptions and develop new treatment targets for BD.

Study of Novel Autoantibodies in Schizophrenia

A recent genome-wide association (GWA) study confirmed 108 genetic loci that were strongly associated with schizophrenia. Fifteen schizophrenia-associated genes were selected for this study based on a number of selection criteria including their high expression in both brain tissues and B-lymphocyte cells. We aimed to investigate whether individuals with schizophrenia showed different levels of plasma IgG antibodies against protein-derived fragments encoded by these 15 genes. A total of 356 plasma samples were used to analyze circulating IgG antibodies against 18 target peptide antigens using an in-house enzyme-linked immunosorbent assay. Of 18 antigens tested, 6 (derived from DPYD, MAD1L1, ZNF804A, DRD2, TRANK1, and MMP16, respectively) showed increased IgG levels and 3 (derived from TSNARE1, TCF4, and VRK2, respectively) showed decreased IgG levels in patients with schizophrenia compared with control subjects. Receiver operating characteristic (ROC) curve analysis revealed that the anti-TRANK1 IgG assay had the area under the ROC curve of 0.68 (95% CI = 0.62-0.73), with the highest sensitivity of 20.7% against specificity of 95.2% among all 18 tests. There was no difference in positivity of anti-double strand DNA IgG between the patient group and the control group and no correlation between total IgG levels and each individual IgG level tested. Although risperidone treatment showed confounding effects on overall IgG levels in the circulation (combined P = .005), anti-TRANK1 IgG levels did not appear to be significantly affected (t = 1.358, P = .176). In conclusion, this study suggests that circulating anti-TRANK1 IgG is likely to serve as a biomarker for identification of a subgroup of schizophrenia.

Neuropsychiatric SLE: from animal model to human

Animal models are a key element in disease research and treatment. In the field of neuropsychiatric lupus research, inbred, transgenic and disease-induced mice provide an opportunity to study the pathogenic routes of this multifactorial illness. In addition to achieving a better understanding of the immune mechanisms underlying the disease onset, supplementary metabolic and endocrine influences have been discovered and investigated. The ever-expanding knowledge about the pathologic events that occur at disease inception enables us to explore new drugs and therapeutic approaches further and to test them using the same animal models. Discovery of the molecular targets that constitute the pathogenic basis of the disease along with scientific advancements allow us to target these molecules with monoclonal antibodies and other specific approaches directly. This novel therapy, termed "targeted biological medication" is a promising endeavor towards producing drugs that are more effective and less toxic. Further work to discover additional molecular targets in lupus' pathogenic mechanism and to produce drugs that neutralize their activity is needed to provide patients with safe and efficient methods of controlling and treating the disease.

Genome-wide association of mood-incongruent psychotic bipolar disorder

Mood-incongruent psychotic features (MICP) are familial symptoms of bipolar disorder (BP) that also occur in schizophrenia (SZ), and may represent manifestations of shared etiology between the major psychoses. In this study we have analyzed three large samples of BP with imputed genome-wide association data and have performed a meta-analysis of 2196 cases with MICP and 8148 controls. We found several regions with suggestive evidence of association (P<10(-6)), although no marker met genome-wide significance criteria. The top associations were on chromosomes: 6q14.2 within the PRSS35/SNAP91 gene complex (rs1171113, P=9.67 × 10(-8)); 3p22.2 downstream of TRANK/LBA1 (rs9834970, P=9.71 × 10(-8)); and 14q24.2 in an intron of NUMB (rs2333194, P=7.03 × 10(-7)). These associations were present in all three samples, and both rs1171113 and rs2333194 were found to be overrepresented in an analysis of MICP cases compared with all other BP cases. To test the relationship of MICP with SZ, we performed polygenic analysis using the Psychiatric GWAS Consortium SZ results and found evidence of association between SZ polygenes and the presence of MICP in BP cases (meta-analysis P=0.003). In summary, our analysis of the MICP phenotype in BP has provided suggestive evidence for association of common variants in several genes expressed in the nervous system. The results of our polygenic analysis provides support for a modest degree of genetic overlap between BP with MICP and SZ, highlighting that phenotypic correlations across syndromes may be due to the influence of polygenic risk factors.

Effects of systemic lupus erythematosus on spatial cognition and cerebral regional metabolic reactivity in BxSB lupus-prone mice

Brain-reactive auto-antibodies appear as key elements in the progressive CNS disturbances associated with systemic lupus erythematosus. The BxSB lupus prone mice are a model of this pathology, in which a gene located on the Y chromosome provokes a sex specific morbidity in males. This study was aimed to establish and characterize the relationships between behavioral disorders, neurological deficiencies and the aged-related immunological perturbations in this murine model. For this purpose, spatial and motor abilities were evaluated in male and female mice at six and 26 weeks of age. The results showed that the older males were greatly altered in their spatial abilities while the young ones and the females, whatever their age, were not. None of the animals had motor skill and motor learning disabilities. These spatial alterations were associated with modifications of basal neuronal activity measured by the cytochrome oxidase histochemical method in several areas directly or indirectly involved in spatial behavior, such as the hippocampus, the amygdala, the parietal and perirhinal cortex. Immunological study allowed us to correlate the behavioral abnormalities to the appearance of antibodies reactivities against cellular and nuclear components.

The spectrum of differential diagnosis in neurological patients with livedo reticularis and livedo racemosa. A literature review

Livedo is a cutaneous sign of striking violaceous netlike patterned erythema of the skin. This dermatological phenomenon is of special interest in the differential diagnosis in neurological patients. In 1907 Ehrmann distinguished two different patterns of livedo: the pathological livedo racemosa and the physiological livedo reticularis. Despite important clinical differences, in the English language literature the heading livedo reticularis is still used for all types of livedo. A literature review about the spectrum of differential diagnosis in patients with livedo reticularis (especially cutis marmorata and amantadine-induced livedo reticularis) and livedo racemosa (especially Sneddon's syndrome, Divry-van Bogaert syndrome, systemic lupus erythematosus, antiphospholipid antibody syndrome, polyarteritis nodosa, cholesterol embolization syndrome, livedoid vasculopathy and haematological diseases) is provided.

Central nervous system involvement in systemic lupus erythematosus: cerebral imaging and serological profile in patients with and without overt neuropsychiatric manifestations

The aim of this study was to evaluate morphological and functional abnormalities by cerebral imaging in a series of systemic lupus erythematosus (SLE) patients with and without overt central nervous system (CNS) manifestations, and to detect possible relationships with clinical parameters and a large panel of autoantibodies, including those reactive against neurotypic and gliotypic antigens. 68 patients with SLE were investigated in a cross-sectional study which included clinical evaluation of symptoms, cerebral magnetic resonance imaging (MRI) and brain single photon emission tomography (SPECT) analysis, electroencephalography (EEG), and serological tests for antibodies directed against nuclear, cytoplasmic neuronal and glial cell-related antigens. The results of this study showed: (1) a significant positive association of (a) anti-glial fibrillary acidic protein (GFAP) serum antibodies with neuropsychiatric (NP) manifestations and (b) anti-serin proteinase 3 (anti-PR3/c-ANCA) serum antibodies with pathological cerebral SPECT; (2) the presence of significantly higher values of (a) SLICC organ damage index in patients with abnormal MRI and (b) SLAM activity index in patients with abnormal SPECT; and (3) the association of (a) abnormal MRI with nonactive NP manifestations and (b) combined abnormality of brain SPECT and MRI with the occurrence of overall overt NP manifestations and with those of the organic/major type. Neuropsychiatric manifestations, namely those of the organic/major type, appeared to be significantly associated to the presence of a serum antibody against GFAP, a gliotypic antigen. There was also evidence of an association between SPECT abnormality and the presence of anti-PR3 (c-ANCA). Furthermore, brain imaging by MRI and SPECT applied to SLE patients appears to express CNS involvement significantly related to specific categories of NP manifestations. The abnormalities detected by the two tests seem to be preferentially associated with different activity phases of the NP disorder or of the lupus disease.

Neurology of systemic autoimmune disorders: a pediatric perspective

Autoimmune disorders can involve patients of any age and organs of any organ system. The central and peripheral nervous systems are frequently among the targets of these diseases. Immune dysfunction often presents in childhood or adolescence. Among the autoimmune disorders that present during childhood and adolescence, systemic lupus erythematosus, dermatomyositis, and Behcet's disease affect the nervous system with some degree of frequency. Furthermore, although juvenile rheumatoid arthritis only rarely affects the nervous system during childhood, it and its adult-onset counterpart may have profound long-term neurological consequences. Both symptomatic and pathophysiologically aimed therapies are important in the treatment of the nervous system sequelae of systemic autoimmune disorders.

Alterations in hypothalamic-pituitary-adrenal function correlated with the onset of murine SLE in MRL +/+ and lpr/lpr mice

Systemic lupus erythematosus (SLE) is a spontaneously occurring, chronic autoimmune disease that can manifest neuropsychiatric abnormalities. The pathways mediating these central changes are not known; however, neuroendocrine alterations associated with inflammation may play a role. Predisposition to and progression of autoimmune disease has been associated with altered hypothalamic-pituitary-adrenal (HPA) function and inflammation has been reported to alter hypothalamic regulation of HPA responses. We investigated whether disease progression in a murine model of systemic lupus erythematosus (MRL +/+. MRL lpr/lpr) resulted in altered expression of HPA regulatory peptides at the level of the hypothalamus and how these alterations related to circulating levels of corticosterone, corticosterone binding globulin, and autoantibody titers. We report that as MRL +/+ and MRL lpr/lpr mice age and circulating levels of autoantibodies increase, there is a decrease in hypothalamic CRH mRNA expression and finally an increase in AVP mRNA expression. We also report that associated with increased autoantibody levels, disease progression, and altered hypothalamic peptide expression there is an increase in circulating levels of corticosterone and a trend for levels of corticosterone binding globulin to decrease. Our data complement previous observations of altered peptidergic regulation of the HPA axis and increased HPA activity during chronic inflammation in exogenously induced rodent models of chronic inflammation and indicate that similar processes may occur in spontaneous murine models of SLE.