Humoral response against glial derived antigens in Parkinson's disease

The humoral immune landscape in Parkinson's disease: Unraveling antibody and B cell changes

Parkinson's disease (PD) is a complex neurodegenerative disorder characterized by the accumulation of α-synuclein (α-syn) in the brain and progressive loss of dopaminergic neurons in the substantia nigra (SN) region of the brain. Although the role of neuroinflammation and cellular immunity in PD has been extensively studied, the involvement of humoral immunity mediated by antibodies and B cells has received less attention. This article provides a comprehensive review of the current understanding of humoral immunity in PD. Here, we discuss alterations in B cells in PD, including changes in their number and phenotype. Evidence mostly indicates a decrease in the quantity of B cells in PD, accompanied by a shift in the population from naïve to memory cells. Furthermore, the existence of autoantibodies that target several antigens in PD has been investigated (i.e., anti-α-syn autoantibodies, anti-glial-derived antigen antibodies, anti-Tau antibodies, antineuromelanin antibodies, and antibodies against the renin-angiotensin system). Several autoantibodies are generated in PD, which may either provide protection or have harmful effects on disease progression. Furthermore, we have reviewed studies focusing on the utilization of antibodies as a potential treatment for PD, both in animal and clinical trials. This review sheds light on the intricate interplay between antibodies and the pathological processes in PD, including complement system activation.

6-Hydroxy-2,2,4-trimethyl-1,2,3,4-tetrahydroquinoline Alleviates Oxidative Stress and NF-κB-Mediated Inflammation in Rats with Experimental Parkinson's Disease

A study was conducted to investigate the effects of different doses of 6-hydroxy-2,2,4-trimethyl-1,2,3,4-tetrahydroquinoline (HTHQ) on motor coordination scores, brain tissue morphology, the expression of tyrosine hydroxylase, the severity of oxidative stress parameters, the levels of the p65 subunit of nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) factor, and the inflammatory response in rats during the development of rotenone-induced Parkinsonism. The findings indicate that HTHQ, with its antioxidant attributes, reduced the levels of 8-isoprostane, lipid oxidation products, and protein oxidation products. The decrease in oxidative stress due to HTHQ led to a reduction in the mRNA content of proinflammatory cytokines and myeloperoxidase activity, accompanying the drop in the expression of the factor NF-κB. These alterations promoted an improvement in motor coordination scores and increased tyrosine hydroxylase levels, whereas histopathological changes in the brain tissue of the experimental animals were attenuated. HTHQ exhibited greater effectiveness than the comparative drug rasagiline based on the majority of variables.

Principal component analysis of routine blood test results with Parkinson's disease: A case-control study

This study aimed to explore the association of routine blood test values and blood cell ratios with the risk or severity of Parkinson's disease (PD). The medical records of 453 PD patients and 436 controls were retrospectively reviewed. The severity of PD was quantified by the modified Hoehn-Yahr (HY) scale. We performed principal component analysis (PCA) of significant values/ratios and used logistic regression analysis to explore the relationship between principal components (PCs) and the risk of PD. Spearman correlation and ordinal logistic regression analyses were performed to explore the relationship between indicators and the severity of PD. The PCA generated 9 PCs, which contributed to 90.86% of the total variance. Logistic regression analysis revealed positive associations of PC2 (a measure monocyte ratios) and PC6 (a measure of platelet ratios and volume) and negative associations of PC1 (a comprehensive measure of lymphocyte, eosinophil, neutrophil, and red blood cell values), PC4 (a measure of red blood cell values), and PC7 (a measure of red blood cell values and platelet volume) with the risk of PD. However, we observed no associations of variables with the severity of PD. In conclusion, PCA reduced the dimensionality of the data. Peripheral blood disorders may be associated with PD.

The Functional Roles and Applications of Immunoglobulins in Neurodegenerative Disease

Natural autoantibodies, immunoglobulins (Igs) that target self-proteins, are common in the plasma of healthy individuals; some of the autoantibodies play pathogenic roles in systemic or tissue-specific autoimmune diseases, such as rheumatoid arthritis and systemic lupus erythematosus. Recently, the field of autoantibody-associated diseases has expanded to encompass neurodegenerative diseases such as Alzheimer's disease (AD) and Parkinson's disease (PD), with related studies examining the functions of Igs in the central nervous system (CNS). Recent evidence suggests that Igs have various effects in the CNS; these effects are associated with the prevention of neurodegeneration, as well as induction. Here, we summarize the functional roles of Igs with respect to neurodegenerative disease (AD and PD), focusing on the target antigens and effector cell types. In addition, we review the current knowledge about the roles of these antibodies as diagnostic markers and immunotherapies.

Antigenic Targets of Patient and Maternal Autoantibodies in Autism Spectrum Disorder

Autism spectrum disorder (ASD) is a neurodevelopmental disorder whose behavioral symptoms become apparent in early childhood. The underlying pathophysiological mechanisms are only partially understood and the clinical manifestations are heterogeneous in nature, which poses a major challenge for diagnosis, prognosis and intervention. In the last years, an important role of a dysregulated immune system in ASD has emerged, but the mechanisms connecting this to a disruption of brain development are still largely unknown. Although ASD is not considered as a typical autoimmune disease, self-reactive antibodies or autoantibodies against a wide variety of targets have been found in a subset of ASD patients. In addition, autoantibodies reactive to fetal brain proteins have also been described in the prenatal stage of neurodevelopment, where they can be transferred from the mother to the fetus by transplacental transport. In this review, we give an extensive overview of the antibodies described in ASD according to their target antigens, their different origins, and timing of exposure during neurodevelopment.

Changes in concentrations of tau-reactive antibodies are dependent on sex in Alzheimer's disease patients

The presence of pre-existing natural antibodies against Alzheimer's disease (AD) pathological proteins might interfere with immune responses to therapeutic vaccination with these proteins. We aimed to compare levels of antibodies in CSF and serum: We observed higher reactivity of natural tau-reactive antibodies towards phosphorylated bovine tau protein than to human recombinant (non-phosphorylated) tau protein. Males with MCI-AD had higher amounts of these antibodies than corresponding controls. Concentrations of antibodies were lower in females with the MCI-AD than in control females. These findings may have implications for tau vaccination trials.

A Panel of Autoantibodies Against Neural Proteins as Peripheral Biomarker for Pesticide-Induced Neurotoxicity

In the present study, we screened the sera of subjects chronically exposed to mixtures of pesticides (composed mainly of organophosphorus compounds (OPs) and others) and developed neurological symptoms for the presence of autoantibodies against cytoskeletal neural proteins. OPs have a well-characterized clinical profile resulting from acute cholinergic crisis. However, some of these compounds cause neuronal degeneration and demyelination known as organophosphorus compound-induced delayed neurotoxicity (OPIDN) and/or organophosphorus compound-induced chronic neurotoxicity (OPICN). Studies from our group have demonstrated the presence of autoantibodies to essential neuronal and glial proteins against cytoskeletal neural proteins in patients with chemical-induced brain injury. In this study, we screened the serum of 50 pesticide-exposed subjects and 25 non-exposed controls, using Western blot analysis against the following proteins: neurofilament triplet proteins (NFPs), tubulin, microtubule-associated tau proteins (Tau), microtubule-associated protein-2 (MAP-2), myelin basic protein (MBP), myelin-associated glycoprotein (MAG), glial fibrillary acidic protein (GFAP), calcium-calmodulin kinase II (CaMKII), glial S100-B protein, and alpha-synuclein (SNCA). Serum reactivity was measured as arbitrary chemiluminescence units. As a group, exposed subjects had significantly higher levels of autoantibody reactivity in all cases examined. The folds of increase in of autoantibodies against neural proteins of the subjects compared to healthy humans in descending order were as follows: MBP, 7.67, MAG 5.89, CaMKII 5.50, GFAP 5.1, TAU 4.96, MAP2 4.83, SNCA 4.55, NFP 4.55, S-100B 2.43, and tubulin 1.78. This study has demonstrated the presence of serum autoantibodies to central nervous system-specific proteins in a group of farmers chronically exposed to pesticides who developed neurological signs and symptoms of neural injury. These autoantibodies can be used as future diagnostic/therapeutic target for OP-induced neurotoxicity.

Anti-MAG autoantibodies are increased in Parkinson's disease but not in atypical parkinsonism

There is emerging evidence that glial cells are involved in the neuropathological process in Parkinson's disease (PD) in addition to degeneration of neuronal structures. Recently, we confirmed the presence of an adaptive immune response against different glial-derived antigens in PD, with a possible role of anti-MAG, anti-MBP and anti-PLP antibodies in the disease progression. The aim of the present study was to assess humoral response against myelin-associated glycoprotein (MAG) in patients with parkinsonism (both idiopathic and atypical) to check whether these antibodies could serve as biomarkers of PD, its severity and progression. Anti-MAG autoantibodies were measured by an ELISA system in 99 PD patients, 33 atypical parkinsonism patients, and 36 control subjects. In PD patients, anti-MAG IgM autoantibodies were significantly higher in comparison to healthy control subjects (p = 0.038). IgM anti-MAG autoantibodies titers were also significantly higher in the whole group of patients with parkinsonism (either idiopathic or atypical) in comparison to healthy control subjects (1.88 ± 0.84 vs 1.70 ± 1.19, p = 0.017). This difference was mainly driven by the PD group, as the atypical parkinsonism group did not differ significantly from the control group in anti-MAG antibody levels (p = 0.51). A negative correlation between anti-MAG levels and disease duration was found in PD patients. Our study provides evidence for an increased production of autoantibodies against a protein of glial origin in PD. The negative correlation between anti-MAG antibodies and disease duration may suggest possible involvement of the immune system in disease progression. Increasing evidence that glia are involved in the neurodegenerative process to a greater extent than previously thought may turn out be useful in the search for biomarkers of the neurodegenerative process in PD.

Correlation between antibodies to bisphenol A, its target enzyme protein disulfide isomerase and antibodies to neuron-specific antigens

Evidence continues to increase linking autoimmunity and other complex diseases to the chemicals commonly found in our environment. Bisphenol A (BPA) is a synthetic monomer used widely in many forms, from food containers to toys, medical products and many others. The potential for BPA to participate as a triggering agent for autoimmune diseases is likely due to its known immunological influences. The goal of this research was to determine if immune reactivity to BPA has any correlation with neurological antibodies. BPA binds to a target enzyme called protein disulfide isomerase (PDI). Myelin basic protein (MBP) and myelin oligodendrocyte glycoprotein (MOG) are neuronal antigens that are target sites for neuroinflammation and neuroautoimmunity. We determined the co‐occurrence of anti‐MBP and anti‐MOG antibodies with antibodies made against BPA bound to human serum albumin in 100 healthy human subjects. Correlation between BPA to PDI, BPA to MOG, BPA to MBP, PDI to MBP and PDI to MOG were all highly statistically significant (P < 0.0001). The outcome of our study suggests that immune reactivity to BPA‐human serum albumin and PDI has a high degree of statistical significance with substantial correlation with both MBP and MOG antibody levels. This suggests that BPA may be a trigger for the production of antibodies against PDI, MBP and MOG. Immune reactivity to BPA bound to human tissue proteins may be a contributing factor to neurological autoimmune disorders. Further research is needed to determine the exact relationship of these antibodies with neuroautoimmunities. Copyright © 2016 The Authors Journal of Applied Toxicology Published by John Wiley & Sons Ltd.

This study investigated correlation of bisphenol A bound to human albumin antibodies with protein disulfide isomerase antibodies, myelin oligodendrocyte glycoprotein antibodies and myelin basic protein antibodies.

Can Antibodies Against Glial Derived Antigens be Early Biomarkers of Hippocampal Demyelination and Memory Loss in Alzheimer's Disease?

BACKGROUND

Alzheimer's disease (AD) is known to exhibit well characterized pathologies including the extracellular accumulation of amyloid plaques, intra-axonal presence of neurofibrillary tangles, and glial hypertrophy. Nevertheless, the nature of myelin pathology in AD has not been well studied. Recent studies on animal models of AD, however, revealed focal demyelination within amyloid-β plaques in hippocampus.

OBJECTIVES

In a view of this finding, we decided to assess humoral response against proteins of myelin sheath in AD, in the hope of identifying early biomarkers of memory loss and neuropathological process characteristic of AD.

METHODS

We assessed antibodies levels against proteins of the myelin sheath: myelin oligodendrocyte glycoprotein (MOG), myelin basic protein (MBP), myelin-associated glycoprotein (MAG), and proteolipoprotein (PLP) in sera of 26 AD patients and 26 healthy controls, using commercially available ELISA system (Mediagnost, Germany).

RESULTS

In the AD patient subgroup, significantly higher titers were observed for all types of assessed IgG autoantibodies compared to healthy control subjects (anti-MOG, anti-MAG, anti-MBP, anti-PLP). The titers of most of the investigated IgM antibodies were also higher in AD patients (p <  0.05), with the exception of anti-MAG IgM antibodies (p >  0.05).

CONCLUSION

The study provides the evidence for the significantly increased production of autoantibodies against proteins of myelin sheath in AD. These results can be of importance in the light of emerging data from animal models of AD, indicating early demyelination of hippocampal region. Further studies on larger population are necessary to confirm whether these autoantibodies could serve as early biomarkers of AD in humans.

Proteomic analysis for early neurodegenerative biomarker detection in an animal model

The exposure to xenobiotics in the early stages of life represents the most important component in the etiology of many neurodegenerative disorders. Proteomic analysis of plasma and brain samples from early life treated animal model was performed in order to identify early biomarkers of neurodegeneration. Two-dimensional gel electrophoresis followed by liquid chromatography-tandem mass spectrometry identified four proteins in the plasma of adolescent rats that deviated from the control group. Low expression levels of transthyretin and plasma transferrin, and the absence of long-chain fatty acid transport 1 were measured. On the other hand, the same proteomic approach was done on striatum of an adult rat model of neurodegeneration. Mitochondrial aspartate aminotransferase and voltage-dependent anion channel were under expressed, while mitochondrial malate dehydrogenase, myelin basic protein and ubiquitin-60S ribosomal protein L40 were absent in striatum of animal model compared to control group. Data show that early biomarkers for the diagnosis of neurodegeneration can be obtained by proteomic analysis, starting from adolescent age and the results highlight the time frame for the onset of neurodegeneration due to early exposure to xenobiotics.