Systemic inflammation activates coagulation and immune cell infiltration pathways in brains with propagating α-synuclein fibril aggregates.

Synucleinopathies are a group of diseases characterized by brain aggregates of α-synuclein (α-syn). The gradual accumulation of α-syn and the role of inflammation in early-stage pathogenesis remain poorly understood. We explored this interaction by inducing chronic inflammation in a common pre-clinical synucleinopathy mouse model. Three weeks post unilateral intra-striatal injections of human α-syn pre-formed fibrils (PFF), mice underwent repeated intraperitoneal injections of 1 mg/ml lipopolysaccharide (LPS) for 3 weeks. Histological examinations of the ipsilateral site showed phospho-α-syn regional spread and LPS-induced neutrophil recruitment to the brain vasculature. Biochemical assessment of the contralateral site confirmed spreading of α-syn aggregation to frontal cortex and a rise in intracerebral TNF-α, IL-1ß, IL-10 and KC/GRO cytokines levels due to LPS. No LPS-induced exacerbation of α-syn pathology load was observed at this stage. Proteomic analysis was performed contralateral to the PFF injection site using LC-MS/MS. Subsequent downstream Reactome Gene-Set Analysis indicated that α-syn pathology alters mitochondrial metabolism and synaptic signaling. Chronic LPS-induced inflammation further lead to an overrepresentation of pathways related to fibrin clotting as well as integrin and B cell receptor signaling. Western blotting confirmed a PFF-induced increase in fibrinogen brain levels and a PFF + LPS increase in Iba1 levels, indicating activated microglia. Splenocyte profiling revealed changes in T and B cells, monocytes, and neutrophils populations due to LPS treatment in PFF injected animals. In summary, early α-syn pathology impacts energy homeostasis pathways, synaptic signaling and brain fibrinogen levels. Concurrent mild systemic inflammation may prime brain immune pathways in interaction with peripheral immunity.

A maturational shift in the frontal cortex synaptic transcriptional landscape underlies schizophrenia-relevant behavioural traits: A congenital rat model.

Disruption of brain development early in life may underlie the neurobiology behind schizophrenia. We have reported more immature synaptic spines in the frontal cortex (FC) of adult Roman High-Avoidance (RHA-I) rats, a behavioural model displaying schizophrenia-like traits. Here, we performed a whole transcriptome analysis in the FC of 4 months old male RHA-I (n=8) and its counterpart, the Roman Low-Avoidance (RLA-I) (n=8). We identified 203 significant genes with overrepresentation of genes involved in synaptic function. Next, we performed a gene set enrichment analysis (GSEA) for genes co-expressed during neurodevelopment. Gene networks were obtained by weighted gene co-expression network analysis (WGCNA) of a transcriptomic dataset containing human FC during lifespan (n=269). Out of thirty-one functional gene networks, six were significantly enriched in the RHA-I. These were differentially regulated during infancy and enriched in biological ontologies related to myelination, synaptic function, and immune response. We validated differential gene expression in a new cohort of adolescent (<=2 months old) and young-adult (>=3 months old) RHA-I and RLA-I rats. The results confirmed overexpression of Gsn, Nt5cd1, Ppp1r1b, and Slc9a3r1 in young-adult RHA-I, while Cables1, a regulator of Cdk5 phosphorylation in actin regulation and involved in synaptic plasticity and maturation, was significantly downregulated in adolescent RHA-I. This age-related expression change was also observed for presynaptic components Snap25 and Snap29. Our results show a different maturational expression profile of synaptic components in the RHA-I strain, supporting a shift in FC maturation underlying schizophrenia-like behavioural traits and adding construct validity to this strain as a neurodevelopmental model.

Behavioral and biochemical effects of alcohol withdrawal in female C3H/HeNRj and C57BL/6JRj mice.

Background: Alcohol use disorder (AUD) is a major problem of our society and is often characterized and worsened by relapse. Prolonged alcohol exposure leads to numerous biochemical alterations that, upon cessation of alcohol intake, cause an array of immediate and lasting withdrawal symptoms. Acute withdrawal and neuroinflammation can be harmful in themselves, and lasting withdrawal symptoms contribute to relapse. Here, we conducted an initial feasibility study assessing several behavioral and neurochemical factors in female C3H/HeNRj (C3H) and C57BL/6JRj (B6) mice to determine which strain showed the clearest alcohol withdrawal symptoms during long-term abstinence and neurochemical alterations following re-exposure. Methods: Female C3H and B6 mice (n = 12 per group/strain) were intermittently exposed to alcohol-containing or control liquid diets for 3 weeks. Acute and prolonged withdrawal symptoms were assessed over a period of 3 weeks using a battery of behavioral test, comprised of alcohol self-administration, anhedonia, hyperalgesia, anxiety-like and depressive-like disturbances. Brain inflammation was measured by multiplex cytokine assay. Monoamine levels in the hippocampus and striatum, as well as exploratory analyses of cations levels in the cerebellum, were assessed by High-Performance Liquid Chromatography (HPLC). Results: Both C3H and B6 alcohol-exposed mice displayed decreased saccharin intake or preference and higher stress levels assessed by ultrasonic vocalizations (USVs) recordings. B6 but not C3H alcohol-exposed mice also exhibited a slower decline of alcohol oral self-administration (OSA), hyperalgesia, elevated brain TNF-α and elevated serotonin turnover. Conclusion: Our findings highlight the suitability of the B6 strain to study the behavioral and neurochemical alterations caused by alcohol withdrawal and the potential efficacy of experimental treatments, not only in early detoxification, but also in prolonged abstinence. The feasibility of these assays is important because long-lasting withdrawal symptoms are often the main cause of relapse in alcohol-dependent patients.

Urinary tract infections trigger synucleinopathy via the innate immune response.

Symptoms in the urogenital organs are common in multiple system atrophy (MSA), also in the years preceding the MSA diagnosis. It is unknown how MSA is triggered and these observations in prodromal MSA led us to hypothesize that synucleinopathy could be triggered by infection of the genitourinary tract causing ɑ-synuclein (ɑSyn) to aggregate in peripheral nerves innervating these organs. As a first proof that peripheral infections could act as a trigger in MSA, this study focused on lower urinary tract infections (UTIs), given the relevance and high frequency of UTIs in prodromal MSA, although other types of infection might also be important triggers of MSA. We performed an epidemiological nested-case control study in the Danish population showing that UTIs are associated with future diagnosis of MSA several years after infection and that it impacts risk in both men and women. Bacterial infection of the urinary bladder triggers synucleinopathy in mice and we propose a novel role of ɑSyn in the innate immune system response to bacteria. Urinary tract infection with uropathogenic E. coli results in the de novo aggregation of ɑSyn during neutrophil infiltration. During the infection, ɑSyn is released extracellularly from neutrophils as part of their extracellular traps. Injection of MSA aggregates into the urinary bladder leads to motor deficits and propagation of ɑSyn pathology to the central nervous system in mice overexpressing oligodendroglial ɑSyn. Repeated UTIs lead to progressive development of synucleinopathy with oligodendroglial involvement in vivo. Our results link bacterial infections with synucleinopathy and show that a host response to environmental triggers can result in ɑSyn pathology that bears semblance to MSA.

Brain proteome profiling implicates the complement and coagulation cascade in multiple system atrophy brain pathology.

BACKGROUND: Multiple system atrophy (MSA) is a rare, progressive, neurodegenerative disorder presenting glia pathology. Still, disease etiology and pathophysiology are unknown, but neuro-inflammation and vascular disruption may be contributing factors to the disease progression. Here, we performed an ex vivo deep proteome profiling of the prefrontal cortex of MSA patients to reveal disease-relevant molecular neuropathological processes. Observations were validated in plasma and cerebrospinal fluid (CSF) of novel cross-sectional patient cohorts. METHODS: Brains from 45 MSA patients and 30 normal controls (CTRLs) were included. Brain samples were homogenized and trypsinized for peptide formation and analyzed by high-performance liquid chromatography tandem mass spectrometry (LC-MS/MS). Results were supplemented by western blotting, immuno-capture, tissue clearing and 3D imaging, immunohistochemistry and immunofluorescence. Subsequent measurements of glial fibrillary acid protein (GFAP) and neuro-filament light chain (NFL) levels were performed by immunoblotting in plasma of 20 MSA patients and 20 CTRLs. Finally, we performed a proteome profiling of 144 CSF samples from MSA and CTRLs, as well as other parkinsonian disorders. Data were analyzed using relevant parametric and non-parametric two-sample tests or linear regression tests followed by post hoc tests corrected for multiple testing. Additionally, high-throughput bioinformatic analyses were applied. RESULTS: We quantified more than 4,000 proteins across samples and identified 49 differentially expressed proteins with significantly different abundances in MSA patients compared with CTRLs. Pathway analyses showed enrichment of processes related to fibrinolysis and complement cascade activation. Increased fibrinogen subunit ß (FGB) protein levels were further verified, and we identified an enriched recognition of FGB by IgGs as well as intra-parenchymal accumulation around blood vessels. We corroborated blood-brain barrier leakage by a significant increase in GFAP and NFL plasma levels in MSA patients that correlated to disease severity and/or duration. Proteome profiling of CSF samples acquired during the disease course, confirmed increased total fibrinogen levels and immune-related components in the soluble fraction of MSA patients. This was also true for the other atypical parkinsonian disorders, dementia with Lewy bodies and progressive supra-nuclear palsy, but not for Parkinson's disease patients. CONCLUSION: Our results implicate activation of the fibrinolytic cascade and immune system in the brain as contributing factors in MSA associated with a more severe disease course.

Alpha-Synuclein Autoimmune Decline in Prodromal Multiple System Atrophy and Parkinson's Disease.

Multiple-system trophy (MSA) and Parkinson's Disease (PD) are both progressive, neurodegenerative diseases characterized by neuropathological deposition of aggregated alpha-synuclein (αSyn). The causes behind this aggregation are still unknown. We have reported aberrancies in MSA and PD patients in naturally occurring autoantibodies (nAbs) against αSyn (anti-αSyn-nAbs), which are important partakers in anti-aggregatory processes, immune-mediated clearance, and anti-inflammatory functions. To elaborate further on the timeline of autoimmune aberrancies towards αSyn, we investigated here the Immunoglobulin (Ig) affinity profile and subclass composition (IgG-total, IgG1-4 and IgM) of anti-αSyn-nAbs in serum samples from prodromal (p) phases of MSA and PD. Using an electrochemiluminescence competition immunoassay, we confirmed that the repertoire of high-affinity anti-αSyn-nAbs is significantly reduced in pMSA and pPD. Further, we demonstrated that pPD had increased anti-αSyn IgG-total levels compared to pMSA and controls, concordant with increased anti-αSyn IgG1 levels in pPD. Anti-αSyn IgG2 and IgG4 levels were reduced in pMSA and pPD compared with controls, whereas anti-αSyn IgG3 levels were reduced in pMSA compared to pPD and controls. The results indicate that the impaired reactivity towards αSyn occurs prior to disease onset. The apparent lack of high-affinity anti-αSyn nAbs may result in reduced clearance of αSyn, leading to aggregation of the protein. Thus, this study provides novel insights into possible causes behind the pathogenesis in synucleinopathies such as MSA and PD.

Passive Immunization in Alpha-Synuclein Preclinical Animal Models.

Alpha-synucleinopathies include Parkinson's disease, dementia with Lewy bodies, pure autonomic failure and multiple system atrophy. These are all progressive neurodegenerative diseases that are characterized by pathological misfolding and accumulation of the protein alpha-synuclein (αsyn) in neurons, axons or glial cells in the brain, but also in other organs. The abnormal accumulation and propagation of pathogenic αsyn across the autonomic connectome is associated with progressive loss of neurons in the brain and peripheral organs, resulting in motor and non-motor symptoms. To date, no cure is available for synucleinopathies, and therapy is limited to symptomatic treatment of motor and non-motor symptoms upon diagnosis. Recent advances using passive immunization that target different αsyn structures show great potential to block disease progression in rodent studies of synucleinopathies. However, passive immunotherapy in clinical trials has been proven safe but less effective than in preclinical conditions. Here we review current achievements of passive immunotherapy in animal models of synucleinopathies. Furthermore, we propose new research strategies to increase translational outcome in patient studies, (1) by using antibodies against immature conformations of pathogenic αsyn (monomers, post-translationally modified monomers, oligomers and protofibrils) and (2) by focusing treatment on body-first synucleinopathies where damage in the brain is still limited and effective immunization could potentially stop disease progression by blocking the spread of pathogenic αsyn from peripheral organs to the brain.

Oxytocin attenuates schizophrenia-like reduced sensorimotor gating in outbred and inbred rats in line with strain differences in CD38 gene expression.

Prepulse inhibition (PPI) of the startle response is a measure of sensorimotor gating that is impaired in many clinical conditions, including schizophrenia. The inbred Roman high-avoidance (RHA) rats, compared to their low-avoidance (RLA) counterparts, show distinct schizophrenia-like phenotypes, such as spontaneous deficits in PPI accompanied by decreased medial prefrontal cortex (mPFC) activity and volume. Schizophrenia-like deficits are usually attenuated by antipsychotic drugs, but these drugs often produce severe side effects. In order to reduce these side effects, the neuropeptide oxytocin has been proposed as an alternative natural antipsychotic for schizophrenia. Here, we examined the effects of peripheral oxytocin administration (saline, 0.04, and 0.2 mg/kg) on PPI in the RHA vs. RLA rats, as well as in the outbred heterogeneous stock (HS) rats. Our results showed that oxytocin increased PPI in the HS rats and attenuated PPI deficits in the RHA rats, but it did not significantly affect PPI in the RLAs. To explore whether these divergent effects were associated with differences in oxytocinergic mechanisms, we analyzed gene expression of the oxytocin receptor (OXTR) and the regulator of oxytocin release (CD38) in the mPFC of the Roman rats. Consistent with the differential oxytocin effects on PPI (RHA > RLA), constitutive CD38 expression was reduced in the RHA rats compared to the RLAs, while oxytocin administration increased OXTR expression in both strains. Overall, the present work reveals that oxytocin administration shows antipsychotic-like effects on PPI in outbred and inbred rats, and it suggests that these effects may be related to basal differences in oxytocin-mediated mechanisms in the mPFC.

DNAJB6b is Downregulated in Synucleinopathies.

BACKGROUND: α-synuclein (α-syn) aggregation contributes to the progression of multiple neurodegenerative diseases. We recently found that the isoform b of the co-chaperone DNAJB6 is a strong suppressor of α-syn aggregation in vivo and in vitro. However, nothing is known about the role of the endogenous isoform b of DNAJB6 (DNAJB6b) in health and disease, due to lack of specific antibodies. OBJECTIVE: Here we generated a novel anti-DNAJB6b antibody to analyze the localization and expression of this isoform in cells, in tissue and in clinical material. METHODS: To address this we used immunocytochemistry, immunohistochemistry, as well as a novel quantitative DNAJB6 specific ELISA method. RESULTS: The endogenous protein is mainly expressed in the cytoplasm and in neurites in vitro, where it is found more in dendrites than in axons. We further verified in vivo that DNAJB6b is expressed in the dopaminergic neurons of the substantia nigra pars compacta (SNpc), which is a neuronal subpopulation highly sensitive to α-syn aggregation, that degenerate to a large extend in patients with Parkinson's disease (PD) and multiple system atrophy (MSA). When we analyzed the expression levels of DNAJB6b in brain material from PD and MSA patients, we found a downregulation of DNAJB6b by use of ELISA based quantification. Interestingly, this was also true when analyzing tissue from patients with progressive supranuclear palsy, a taupathic atypical parkinsonian disorder. However, the total level of DNAJB6 was upregulated in these three diseases, which may indicate an upregulation of the other major isoform of DNAJB6, DNAJB6a. CONCLUSION: This study shows that DNAJB6b is downregulated in several different neurodegenerative diseases, which makes it an interesting target to further investigate in relation to amyloid protein aggregation and disease progression.

PIAS2-mediated blockade of IFN-ß signaling: a basis for sporadic Parkinson disease dementia.

Familial Parkinson disease (PD) is associated with rare genetic mutations, but the etiology in most patients with sporadic (s)PD is largely unknown, and the basis for its progression to dementia (sPDD) is poorly characterized. We have identified that loss of IFNß or IFNAR1, the receptor for IFNα/ß, causes pathological and behavioral changes resembling PDD, prompting us to hypothesize that dysregulated genes in IFNß-IFNAR signaling pathway predispose one to sPD. By transcriptomic analysis, we found defective neuronal IFNß-IFNAR signaling, including particularly elevated PIAS2 associated with sPDD. With meta-analysis of GWASs, we identified sequence variants in IFNß-IFNAR-related genes in sPD patients. Furthermore, sPDD patients expressed higher levels of PIAS2 mRNA and protein in neurons. To determine its function in brain, we overexpressed PIAS2 under a neuronal promoter, alone or with human α-synuclein, in the brains of mice, which caused motor and cognitive impairments and correlated with intraneuronal phosphorylated (p)α-synuclein accumulation and dopaminergic neuron loss. Ectopic expression of neuronal PIAS2 blocked mitophagy, increased the accumulation of senescent mitochondrial and oxidative stress, as evidenced by excessive oxDJ1 and 8OHdG, by inactivating ERK1/2-P53 signaling. Conversely, PIAS2 knockdown rescued the clinicopathological manifestations of PDD in Ifnb-/- mice on restoring mitochondrial homeostasis, oxidative stress, and pERK1/2-pP53 signaling. The regulation of JAK-STAT2-PIAS2 signaling was crucial for neurite outgrowth and neuronal survival and excitability and thus might prevent cognitive impairments. Our findings provide insights into the progression of sPD and dementia and have implications for new therapeutic approaches.

Cerebrospinal fluid and plasma distribution of anti-α-synuclein IgMs and IgGs in multiple system atrophy and Parkinson's disease.

INTRODUCTION: Ubiquitous naturally occurring autoantibodies (nAbs) against alpha-synuclein (α-syn) may play important roles in the pathogenesis of Multiple System Atrophy (MSA) and Parkinson's disease (PD). Recently, we reported reduced high-affinity/avidity anti-α-syn nAbs levels in plasma from MSA and PD patients, along with distinct inter-group immunoglobulin (Ig)G subclass distributions. The extent to which these observations in plasma may reflect corresponding levels in the cerebrospinal fluid (CSF) is unknown. METHODS: Using competitive and indirect ELISAs, we investigated the affinity/avidity of CSF anti-α-syn nAbs as well as the CSF and plasma distribution of IgG subclasses and IgM nAbs in a cross-sectional cohort of MSA and PD patients. RESULTS: Repertoires of high-affinity/avidity anti-α-syn IgG nAbs were reduced in CSF samples from MSA and PD patients compared to controls. Furthermore, anti-α-syn IgM nAb levels were relatively lower in CSF and plasma from MSA patients but were reduced only in plasma from PD patients. Interestingly, anti-α-syn IgG subclasses presented disease-specific profiles both in CSF and plasma. Anti-α-syn IgG1, IgG2 and IgG3 levels were relatively increased in CSF of MSA patients, whereas PD patients showed increased anti-α-syn IgG2 and reduced anti-α-syn IgG4 levels. CONCLUSIONS: Differences in the plasma/CSF distribution of anti-α-syn nAbs seem to be a common feature of synucleinopathies. Our data add further support to the notion that MSA and PD patients may have compromised immune reactivity towards α-syn. The differing α-syn-specific systemic immunological responses may reflect their specific disease pathophysiologies. These results are encouraging for further investigation of these immunological mechanisms in neurodegenerative diseases.

Quantitative Cellular Changes in the Thalamus of Patients with Multiple System Atrophy.

The thalamus is a brain region consisting of anatomical and functional connections between various spinal, subcortical, and cortical regions, which has a putative role in the clinical manifestation of Multiple System Atrophy (MSA). Previous stereological studies have reported significant anatomical alterations in diverse brain regions of MSA patients, including the cerebral cortex, basal ganglia and white matter, but no quantitative studies have examined the thalamus. To establish the extent of thalamic involvement, we applied stereological methods to estimate the total number of neurons and glial cells (oligodendrocytes, astrocytes and microglia) as well as the volume in two thalamic sub-regions, the mediodorsal nucleus (MDT) and the anterior principal nucleus (APn), in brains from ten MSA patients and 11 healthy control subjects. Compared to healthy controls, MSA patients had significantly fewer neurons (26%) in the MDT, but not the APn. We also found significantly more astrocytes (32%) and microglia (54%) in the MDT, with no such changes in the APn. Finally, we saw no group differences in the total number of oligodendrocytes. Our findings show a region-specific loss of thalamic neurons that occurs without loss of oligodendrocytes, whereas thalamic microgliosis seems to occur alongside astrogliosis. These pathological changes in the thalamus may contribute to the cognitive impairment seen in most patients with MSA.

TDP-43-specific Autoantibody Decline in Patients With Amyotrophic Lateral Sclerosis.

OBJECTIVE: We hypothesize alterations in the quality and quantity of anti-43-kDa TAR DNA-binding protein (TDP-43) naturally occurring autoantibodies (NAbs) in patients with amyotrophic lateral sclerosis (ALS); therefore, we assessed relative binding properties of anti-TDP-43 NAbs composite in plasma from patients with ALS in comparison with healthy individuals. METHODS: ELISA competition assay was used to explore the apparent avidity/affinity of anti-TDP-43 NAbs in plasma from 51 normal controls and 30 patients with ALS. Furthermore, the relative levels of anti-TDP-43 NAbs within the immunoglobulin (Ig) classes of IgG (isotype IgG1-4) and IgMs were measured using classical indirect ELISA. The occurring results were hereafter correlated with the measures of disease duration and disease progression. RESULTS: High-avidity/affinity anti-TDP-43 NAbs levels were significantly reduced in plasma samples from patients with ALS. In addition, a significant decrease in relative levels of anti-TDP-43 IgG3 and IgM NAbs and a significant increase in anti-TDP-43 IgG4 NAbs were observed in ALS plasma vs controls. Furthermore, a decrease in global IgM and an increase in IgG4 levels were observed in ALS. These aberrations of humoral immunity correlated with disease duration, but did not correlate with ALS Functional Rating Scale-Revised scores. CONCLUSIONS: Our results may suggest TDP-43-specific immune aberrations in patients with ALS. The skewed immune profiles observed in patients with ALS could indicate a deficiency in the clearance capacity and/or blocking of TDP-43 transmission and propagation. The decrease in levels of high affinity/avidity anti-TDP-43 NAbs and IgMs correlates with disease progression and may be disease predictors.

Author Correction: Assessment of brain reference genes for RT-qPCR studies in neurodegenerative diseases.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Epigenetic modulation of AREL1 and increased HLA expression in brains of multiple system atrophy patients.

Multiple system atrophy (MSA) is a rare disease with a fatal outcome. To date, little is known about the molecular processes underlying disease development. Its clinical overlap with related neurodegenerative movement disorders underlines the importance for expanding the knowledge of pathological brain processes in MSA patients to improve distinction from similar diseases. In the current study, we investigated DNA methylation changes in brain samples from 41 MSA patients and 37 healthy controls. We focused on the prefrontal cortex, a moderately affected area in MSA. Using Illumina MethylationEPIC arrays, we investigated 5-methylcytosine (5mC) as well as 5-hydroxymethylcytosine (5hmC) changes throughout the genome. We identified five significantly different 5mC probes (adj. P < 0.05), of which one probe mapping to the AREL1 gene involved in antigen presentation was decreased in MSA patients. This decrease correlated with increased 5hmC levels. Further, we identified functional DNA methylation modules involved in inflammatory processes. As expected, the decreased 5mC levels on AREL1 was concordant with increased gene expression levels of both AREL1 as well as MHC Class I HLA genes in MSA brains. We also investigated whether these changes in antigen-related processes in the brain associated with changes in peripheral mononuclear cells. Using flow cytometry on an independent cohort of MSA patients, we identified a decrease in circulating non-classical CD14+CD16++ blood monocytes, whereas T and NK cell populations were unchanged. Taken together, our results support the view of an active neuroimmune response in brains of MSA patients.

Pathological changes in the cerebellum of patients with multiple system atrophy and Parkinson's disease-a stereological study.

Multiple system atrophy (MSA) and Parkinson's disease (PD) are synucleinopathies characterized by aggregation of α-synuclein in brain cells. Recent studies have shown that morphological changes in terms of cerebral nerve cell loss and increase in glia cell numbers, the degree of brain atrophy and molecular and epidemiological findings are more severe in MSA than PD. In the present study, we performed a stereological comparison of cerebellar volumes, granule and Purkinje cells in 13 patients diagnosed with MSA [8 MSA-P (striatonigral subtype) and 5 MSA-C (olivopontocerebellar subtype)], 12 PD patients, and 15 age-matched control subjects. Only brains from MSA-C patients showed a reduction in the total number of Purkinje cells (anterior lobe) whereas both MSA-P and MSA-C patients had reduced Purkinje cell volumes (perikaryons and nuclei volume). The cerebellum of both diseases showed a reduction in the white matter volume compared to controls. The number of granule cells was unaffected in both diseases. Analyses of cell type-specific mRNA expression supported our structural data. This study of the cerebellum is in line with previous findings in the cerebrum and demonstrates that the degree of morphological changes is more pronounced in MSA-C than MSA-P and PD. Further, our results support an explicit involvement of cerebellar Purkinje cells and white matter connectivity in MSA-C > MSA-P and points to the potential importance of white matter alterations in PD pathology.

Distinct Autoimmune Anti-α-Synuclein Antibody Patterns in Multiple System Atrophy and Parkinson's Disease.

Aggregation of alpha-synuclein (α-syn) is considered to be the major pathological hallmark and driving force of Multiple System Atrophy (MSA) and Parkinson's disease (PD). Immune dysfunctions have been associated with both MSA and PD and recently we reported that the levels of natural occurring autoantibodies (NAbs) with high-affinity/avidity toward α-synuclein are reduced in MSA and PD patients. Here, we aimed to evaluate the plasma immunoglobulin (Ig) composition binding α-syn and other amyloidogenic neuropathological proteins, and to correlate them with disease severity and duration in MSA and PD patients. All participants were recruited from a single neurological unit and the plasma samples were stored for later research at the Bispebjerg Movement Disorder Biobank. All patients were diagnosed according to current consensus criteria. Using multiple variable linear regression analyses, we observed higher levels of anti-α-syn IgG1 and IgG3 NAbs in MSA vs. PD, higher levels of anti-α-syn IgG2 NAbs in PD compared to controls, whereas anti-α-syn IgG4 NAbs were reduced in PD compared to MSA and controls. Anti-α-syn IgM levels were decreased in both MSA and PD. Further our data supported that MSA patients' immune system was affected with reduced IgG1 and IgM global levels compared to PD and controls, with further reduced global IgG2 levels compared to PD. These results suggest distinct autoimmune patterns in MSA and PD. These findings suggest a specific autoimmune physiological mechanism involving responses toward α-syn, differing in neurodegenerative disease with overlapping α-syn pathology.

Inflammatory Bowel Diseases and Parkinson's Disease.

The etiology of Parkinson's disease (PD) is multifactorial, with genetics, aging, and environmental agents all a part of the PD pathogenesis. Widespread aggregation of the α-synuclein protein in the form of Lewy bodies and Lewy neurites, and degeneration of substantia nigra dopamine neurons are the pathological hallmarks of PD. Inflammatory responses manifested by glial reactions, T cell infiltration, and increased expression of inflammatory cytokines, as well as other toxic mediators derived from activated glial cells, are currently recognized as prominent features of PD. Experimental, clinical and epidemiological data suggest that intestinal inflammation contributes to the pathogenesis of PD, and the increasing number of studies suggests that the condition may start in the gastrointestinal system years before any motor symptoms develop. Patients with inflammatory bowel disease (IBD) have a higher risk of developing PD compared with non-IBD individuals. Gene association study has found a genetic link between IBD and PD, and an evidence from animal studies suggests that gut inflammation, similar to that observed in IBD, may induce loss of dopaminergic neurons. Based on preclinical models of PD, it is suggested that the enteric microbiome changes early in PD, and gut infections trigger α-synuclein release and aggregation. In this paper, the possible link between IBD and PD is reviewed based on the available literature. Given the potentially critical role of gastrointestinal pathology in PD pathogenesis, there is reason to suspect that IBD or its treatments may impact PD risk. Thus, clinicians should be aware of PD symptoms in IBD patients.

Increased prefrontal cortex interleukin-2 protein levels and shift in the peripheral T cell population in progressive supranuclear palsy patients.

Accumulating evidence suggests neuroinflammation to be an integrated feature of neurodegeneration. Profiling inflammatory mediators across diseases may reveal common and disease-specific signatures. Here, we focused on progressive supranuclear palsy (PSP), a tauopathy presenting motor and cognitive dysfunction. We screened for 21 cytokines and growth factors in the dorsomedial prefrontal cortex of 16 PSP and 16 control brains using different quantitative techniques. We found and validated increased interleukin (IL)-2 protein levels in the PSP group expressed locally by neurons and glia cells. We further investigated central players in neuroinflammatory pathways and found increased mRNA expression of glycogen synthase kinase 3 beta (GSK3B). IL-2 and GSK3B proteins are T and natural killer (NK) cell regulators and have previously been associated with other neurodegenerative diseases such as Alzheimer's disease, Parkinson's disease and multiple system atrophy. In addition, we identified a shift in peripheral CD4+ and CD8+ T cell populations toward increased numbers of memory and reduced numbers of naive T cells. We also observed increased numbers of CD56+ NK cells, but not of CD56+CD57+ or CD57+ NK cells. Our findings suggest a role for IL-2 in PSP disease processes and point toward active and possibly dysfunctional peripheral immune responses in these patients.

Impaired Wnt Signaling in the Prefrontal Cortex of Alzheimer's Disease.

Wnt pathway is involved in synaptic plasticity and neuronal survival, and alterations in Wnt signaling have previously been reported both in aging and neurodegenerative diseases, including Alzheimer's disease (AD). This study sought to evaluate Wnt signaling pathway interplay integrity across prefrontal lobe structures in AD patients compared to normal aging. Using the open-access BrainCloud™ database, 84 gene expression profiles and clustering effect were analyzed in the dorsomedial prefrontal cortex (PFC) across a time span of 21-78 years of age. Next, expression levels of the selected genes were investigated in post-mortem brain tissue from 30 AD patients and 30 age-matched controls in three interdependent brain areas of the PFC. Results were assessed in relation to Braak stage and cognitive impairment of the patients. We found a general age-related factor in Wnt pathway genes with a group of genes being closely interrelated in their expression across the time span investigated in healthy individuals. This interrelation was altered in the AD brains studied, as several genes presented aberrant transcription, even though not always being altered at protein levels. Noteworthy, beta(ß)-catenin and glycogen synthase kinase 3-beta (GSK3ß) showed a dynamic switch in protein levels and activity, especially in the orbitofrontal cortex and the medial frontal gyrus. A significant decrease in ß-catenin protein levels were inversely associated with increased GSK3ß tyrosine activating phosphorylation, in addition to downstream effects associated with disease progression and cognitive decline. This study is the first that comprehensively evaluates Wnt signaling pathway in the prefrontal cortical lobe structures of AD brains, in relation to age-related coordinated Wnt signaling changes. Our findings further support that increased kinase activity of GSK3ß is associated with AD pathology in the PFC.