S100B polymorphisms are associated with age of onset of Parkinson's disease

Neurodegeneration and inflammation crosstalk: Therapeutic targets and perspectives

Glia, which was formerly considered to exist just to connect neurons, now plays a key function in a wide range of physiological events, including formation of memory, learning, neuroplasticity, synaptic plasticity, energy consumption, and homeostasis of ions. Glial cells regulate the brain's immune responses and confers nutritional and structural aid to neurons, making them an important player in a broad range of neurological disorders. Alzheimer's, ALS, Parkinson's, frontotemporal dementia (FTD), and epilepsy are a few of the neurodegenerative diseases that have been linked to microglia and astroglia cells, in particular. Synapse growth is aided by glial cell activity, and this activity has an effect on neuronal signalling. Each glial malfunction in diverse neurodegenerative diseases is distinct, and we will discuss its significance in the progression of the illness, as well as its potential for future treatment.

The S100B Protein: A Multifaceted Pathogenic Factor More Than a Biomarker

S100B is a calcium-binding protein mainly concentrated in astrocytes in the nervous system. Its levels in biological fluids are recognized as a reliable biomarker of active neural distress, and more recently, mounting evidence points to S100B as a Damage-Associated Molecular Pattern molecule, which, at high concentration, triggers tissue reactions to damage. S100B levels and/or distribution in the nervous tissue of patients and/or experimental models of different neural disorders, for which the protein is used as a biomarker, are directly related to the progress of the disease. In addition, in experimental models of diseases such as Alzheimer's and Parkinson's diseases, amyotrophic lateral sclerosis, multiple sclerosis, traumatic and vascular acute neural injury, epilepsy, and inflammatory bowel disease, alteration of S100B levels correlates with the occurrence of clinical and/or toxic parameters. In general, overexpression/administration of S100B worsens the clinical presentation, whereas deletion/inactivation of the protein contributes to the amelioration of the symptoms. Thus, the S100B protein may be proposed as a common pathogenic factor in different disorders, sharing different symptoms and etiologies but appearing to share some common pathogenic processes reasonably attributable to neuroinflammation.

Extracellular S100B inhibits A-type voltage-gated potassium currents and increases L-type voltage-gated calcium channel activity in dopaminergic neurons

Parkinson's disease (PD) is associated with an increase in secreted S100B within the midbrain and cerebrospinal fluid. In addition, S100B overexpression in mice accelerates the loss of substantia nigra pars compacta dopaminergic (DA) neurons, suggesting a role for this protein in PD pathogenesis. We found that in the mouse SNc, S100B labeled astrocytic processes completely envelop the somata of tyrosine hydroxylase (TH) expressing DA neurons only in male mice. These data suggest that an increase in S100B secretion by astrocytes within the midbrain could play a role in DA dysfunction during early PD. We therefore asked if acute exposure to extracellular S100B alters the activity of identified TH expressing DA neurons in primary mouse midbrain cultures. Acute exposure to 50 pM S100B specifically inhibited A-type voltage-gated potassium currents in TH+ , but not TH- neurons. This was accompanied by ~2-fold increases in the frequency of both intrinsic firing, as well as L-type voltage-gated calcium channel (VGCC)-mediated calcium fluxes only in TH+ neurons. Further, exposure to 100 μM 4-aminopyridine (4-AP), an A-type voltage-gated potassium channel inhibitor, mimicked the S100B mediated increase in intrinsic firing and L-type VGCC-mediated calcium fluxes in TH+ neurons. Taken together, our finding that extracellular S100B alters the activity of native DA neurons via an inhibition of A-type voltage-gated potassium channels has important implications for understanding the pathophysiology of early PD.

A need to reconsider the rehabilitation protocol in patients with idiopathic Parkinson’s disease: Review analysis

Idiopathic Parkinson’s disease is the second most debilitating and progressive neurodegenerative disease affecting the functional activities in day-to-day life. The motor and non-motor symptoms have shown to be a huge functional loss for the subject which has led to compromise their independence. There are varieties of treatment programs proposed as pharmacological, surgical, rehabilitation, allied therapies but none have proven to be the disease modifying treatments in managing the symptoms of Parkinson’s disease patients. Research has shown that discontinuity in the treatment and diminished effects of treatments have drained care givers physically, emotionally, and financially.  In this study we explore the available physiotherapy treatment strategies highlighting the research gaps in articles (n=36). The articles were taken from the databases such as PubMed, Science Direct and Google Scholar by considering the inclusion and exclusion criteria. Though the present research has shown to be significant in improving the motor and non-motor symptoms there are still unanswered questions on the rehabilitation protocols whether they can modify the disease and improve the quality of life among Parkinson’s disease in long term. Exercise have proven to be beneficial, cost effective and low risk which improves the overall health and independence of the patient,  however, the mechanism involved are less understood.

Production of chitosan scaffolds by lyophilization or electrospinning: which is better for peripheral nerve regeneration?

Both lyophilization and electrospinning are commonly used to make chitosan scaffolds. However, it remains unknown which method is better for cell growth. In this study, we established the following groups: (1) lyophilization group-chitosan scaffolds were prepared by lyophilization method and seeded with Schwann cells from Sprague-Dawley rats aged 3-5 days; (2) electrospinning group-chitosan scaffolds were prepared by electrospinning method and seeded with Schwann cells; (3) control group-Schwann cells were cultured on culture dishes. The growth of Schwann cells was evaluated by immunofluorescence and scanning electron microscopy. Western blot assay was performed to explore the mechanism of Schwann cell growth. Both materials were non-toxic and suitable for the growth of Schwann cells. The pores produced by electrospinning were much smaller than those produced by lyophilization. The proliferation rate and adhesion rate of Schwann cells in the electrospinning group were higher than those in the lyophilization group. Schwann cells cultured on electrospinning scaffolds formed a Bungner band-like structure, and a much greater amount of brain-derived neurotrophic factor was secreted, which can promote the growth of neurons. Our findings show that the chitosan scaffold prepared by the electrospinning method has a nanofiber structure that provides an extracellular matrix that is more favorable for cell-cell interactions. The electrospinning method is more suitable for nerve regeneration than the lyophilization method. This research was approved by the Medical Ethical Committee of Dalian Medical University (approval No. AEE1-2016-045) on March 3, 2016.

Proteomic Profile of Saliva in Parkinson's Disease Patients: A Proof of Concept Study

Parkinson’s disease (PD) is a progressive neurodegenerative disorder. It affects many organs. Lewy bodies—a histopathological “hallmark” of PD—are detected in about 75% of PD submandibular gland samples. We hypothesize that saliva can be a source of biomarkers of PD. The aim of the study was to evaluate and compare the salivary proteome of PD patients and healthy controls (HC). Salivary samples from 39 subjects (24 PD patients, mean age 61.6 ± 8.2; 15 HC, mean age 60.9 ± 6.7) were collected. Saliva was collected using RNA-Pro-Sal kits. Label-free LC-MS/MS mass spectrometry was performed to characterize the proteome of the saliva. IPA analysis of upstream inhibitors was performed. A total of 530 proteins and peptides were identified. We observed lower concentrations of S100-A16, ARP2/3, and VPS4B in PD group when compared to HC. We conclude that the salivary proteome composition of PD patients is different than that of healthy controls. We observed a lower concentration of proteins involved in inflammatory processes, exosome formation, and adipose tissue formation. The variability of expression of proteins between the two groups needs to be considered.

S100B gene polymorphisms are associated with the S100B level and Alzheimer's disease risk by altering the miRNA binding capacity

To examine the role of S100B in genetic susceptibility to Alzheimer’s disease (AD), we conducted a case-control study to analyze four polymorphism loci (rs2839364, rs1051169, rs2300403, and rs9722) of the S100B gene and AD risk. We found an independent increased risk of AD in ApoE ε4(-) subjects carrying the rs9722 AA-genotype (OR = 2.622, 95% CI = 1.399–4.915, P = 0.003). Further investigation revealed the serum S100B levels to be lower in rs9722 GG carriers than in rs9722 AA carriers (P = 0.003). We identified three miRNAs (miR-340-3p, miR-593-3p, miR-6827-3p) in which the seed match region covered locus rs9722. Luciferase assays indicated that the rs9722 G allele has a higher binding affinity to miR-6827-3p than the rs9722 A allele, leading to a significantly decreased fluorescence intensity. Subsequent western blot analysis showed that the S100B protein level of SH-SY5Y cells, which carry the rs9722 G allele, decreased significantly following miR-6827-3p stimulation (P = 0.009). The present study suggests that the rs9722 polymorphism may upregulate the expression of S100B by altering the miRNA binding capacity and may thus increase the AD risk. This finding would be of great help for the early diagnosis of AD.

Growing role of S100B protein as a putative therapeutic target for neurological- and nonneurological-disorders

S100B is a calcium-binding protein mainly expressed by astrocytes, but also localized in other definite neural and extra-neural cell types. While its presence in biological fluids is widely recognized as a reliable biomarker of active injury, growing evidence now indicates that high levels of S100B are suggestive of pathogenic processes in different neural, but also extra-neural, disorders. Indeed, modulation of S100B levels correlates with the occurrence of clinical and/or toxic parameters in experimental models of diseases such as Alzheimer's and Parkinson's diseases, amyotrophic lateral sclerosis, muscular dystrophy, multiple sclerosis, acute neural injury, inflammatory bowel disease, uveal and retinal disorders, obesity, diabetes and cancer, thus directly linking the levels of S100B to pathogenic mechanisms. In general, deletion/inactivation of the protein causes the improvement of the disease, whereas its over-expression/administration induces a worse clinical presentation. This scenario reasonably proposes S100B as a common therapeutic target for several different disorders, also offering new clues to individuate possible unexpected connections among these diseases.

Emerging role of S100B protein implication in Parkinson's disease pathogenesis

The exact etiology of Parkinson's disease (PD) remains obscure, lacking effective diagnostic and prognostic biomarkers. In search of novel molecular factors that may contribute to PD pathogenesis, emerging evidence highlights the multifunctional role of the calcium-binding protein S100B that is widely expressed in the brain and predominantly in astrocytes. Preclinical evidence points towards the possible time-specific contributing role of S100B in the pathogenesis of neurodegenerative disorders including PD, mainly by regulating neuroinflammation and dopamine metabolism. Although existing clinical evidence presents some contradictions, estimation of S100B in the serum and cerebrospinal fluid seems to hold a great promise as a potential PD biomarker, particularly regarding the severity of motor and non-motor PD symptoms. Furthermore, given the recent development of S100B inhibitors that are able to cross the blood brain barrier, novel opportunities are arising in the research field of PD therapeutics. In this review, we provide an update on recent advances in the implication of S100B protein in the pathogenesis of PD and discuss relevant studies investigating the biomarker potential of S100B in PD, aiming to shed more light on clinical targeting approaches related to this incurable disorder.

Neurodegeneration and Inflammation-An Interesting Interplay in Parkinson's Disease

Parkinson's disease (PD) is a neurodegenerative disorder, caused by, so far, unknown pathogenetic mechanisms. There is no doubt that pro-inflammatory immune-mediated mechanisms are pivotal to the pathogenicity and progression of the disease. In this review, we highlight the binary role of microglia activation in the pathophysiology of the disorder, both neuroprotective and neuromodulatory. We present how the expression of several cytokines implicated in dopaminergic neurons (DA) degeneration could be used as biomarkers for PD. Viral infections have been studied and correlated to the disease progression, usually operating as trigger factors for the inflammatory process. The gut-brain axis and the possible contribution of the peripheral bowel inflammation to neuronal death, mainly dopaminergic neurons, seems to be a main contributor of brain neuroinflammation. The role of the immune system has also been analyzed implicating a-synuclein in the activation of innate and adaptive immunity. We also discuss therapeutic approaches concerning PD and neuroinflammation, which have been studied in experimental and in vitro models and data stemming from epidemiological studies.

Association of S100B 3'UTR polymorphism with risk of chronic heart failure in a Chinese Han population

To study the correlation between single nucleotide polymorphism (SNP) of the 3' untranslated region (UTR) rs9722 locus in S100B and the risk of chronic heart failure (CHF), plasma levels of S100B protein as well as has-miR-340-3p in a Chinese Han population.A total of 215 patients with CHF (124 ischemic cardiomyopathy (ICM) and 91 dilated cardiomyopathy (DCM)) and 215 healthy controls were recruited to analyze the S100B rs9722 genotype by Sanger sequencing. The levels of hsa-miR-340-3p in the plasma were detected by RT-PCR, and S100B levels were detected by ELISA.The risk of CHF in S100B rs9722 locus T allele carriers was 4.24 times higher than that in those with the C allele (95% CI: 2.84-6.33, P < .001). The association of S100B rs9722 locus SNP with ICM and DCM risk was not affected by factors such as age, gender, and body mass index (BMI). The levels of plasma S100B and hsa-miR-340-3p in patients with ICM and DCM were significantly higher than those in the control group (P < .001). There was no significant difference in plasma S100B levels between patients with ICM and DCM (P > .05). Among ICM, DCM, and control subjects, TT genotype carriers had the highest levels of plasma S100B and hsa-miR-340-3p, followed by the CT genotype and TT genotype, and the difference was statistically significant (P < .05). Plasma hsa-miR-340-3p levels were positively correlated with S100B levels in the control subjects and patients with ICM and DCM.The S100B rs9722 locus SNP is associated with CHF risk in a Chinese Han population.

Nutraceuticals Targeting Generation and Oxidant Activity of Peroxynitrite May Aid Prevention and Control of Parkinson's Disease

Parkinson's disease (PD) is a chronic low-grade inflammatory process in which activated microglia generate cytotoxic factors-most prominently peroxynitrite-which induce the death and dysfunction of neighboring dopaminergic neurons. Dying neurons then release damage-associated molecular pattern proteins such as high mobility group box 1 which act on microglia via a range of receptors to amplify microglial activation. Since peroxynitrite is a key mediator in this process, it is proposed that nutraceutical measures which either suppress microglial production of peroxynitrite, or which promote the scavenging of peroxynitrite-derived oxidants, should have value for the prevention and control of PD. Peroxynitrite production can be quelled by suppressing activation of microglial NADPH oxidase-the source of its precursor superoxide-or by down-regulating the signaling pathways that promote microglial expression of inducible nitric oxide synthase (iNOS). Phycocyanobilin of spirulina, ferulic acid, long-chain omega-3 fatty acids, good vitamin D status, promotion of hydrogen sulfide production with taurine and N-acetylcysteine, caffeine, epigallocatechin-gallate, butyrogenic dietary fiber, and probiotics may have potential for blunting microglial iNOS induction. Scavenging of peroxynitrite-derived radicals may be amplified with supplemental zinc or inosine. Astaxanthin has potential for protecting the mitochondrial respiratory chain from peroxynitrite and environmental mitochondrial toxins. Healthful programs of nutraceutical supplementation may prove to be useful and feasible in the primary prevention or slow progression of pre-existing PD. Since damage to the mitochondria in dopaminergic neurons by environmental toxins is suspected to play a role in triggering the self-sustaining inflammation that drives PD pathogenesis, there is also reason to suspect that plant-based diets of modest protein content, and possibly a corn-rich diet high in spermidine, might provide protection from PD by boosting protective mitophagy and thereby aiding efficient mitochondrial function. Low-protein diets can also promote a more even response to levodopa therapy.

Inflammation biomarker discovery in Parkinson's disease and atypical parkinsonisms

Background

Parkinson’s disease (PD) and atypical parkinsonisms (APD) have overlapping symptoms challenging an early diagnosis. Diagnostic accuracy is important because PD and APD have different prognosis and response to treatment. We aimed to identify diagnostic inflammatory biomarkers of PD and APD in cerebrospinal fluid (CSF) using the multiplex proximity extension assay (PEA) technology and to study possible correlations of biomarkers with disease progression.

Methods

CSF from a longitudinal cohort study consisting of PD and APD patients (PD, n = 44; multiple system atrophy (MSA), n = 14; vascular parkinsonism (VaP), n = 9; and PD with VaP, n = 7) and controls (n = 25) were analyzed.

Results

Concentrations of CCL28 were elevated in PD compared to controls (p = 0.0001). Five other biomarkers differentiated both MSA and PD from controls (p < 0.05) and 10 biomarkers differentiated MSA from controls, of which two proteins, i.e. beta nerve growth factor (β-NGF) and Delta and Notch like epidermal growth factor-related receptor (DNER), were also present at lower levels in MSA compared to PD (both p = 0.032). Two biomarkers (MCP-1 and MMP-10) positively correlated with PD progression (rho > 0.650; p < 0.01).

Conclusions

PEA technique identified potential new CSF biomarkers to help to predict the prognosis of PD. Also, we identified new candidate biomarkers to distinguish MSA from PD.

Characteristic response of striatal astrocytes to dopamine depletion

Astrocytes and astrocyte-related proteins play important roles in maintaining normal brain function, and also regulate pathological processes in brain diseases and injury. However, the role of astrocytes in the dopamine-depleted striatum remains unclear. A rat model of Parkinson’s disease was therefore established by injecting 10 μL 6-hydroxydopamine (2.5 μg/μL) into the right medial forebrain bundle. Immunohistochemical staining was used to detect the immunoreactivity of glial fibrillary acidic protein (GFAP), calcium-binding protein B (S100B), and signal transducer and activator of transcription 3 (STAT3) in the striatum, and to investigate the co-expression of GFAP with S100B and STAT3. Western blot assay was used to measure the protein expression of GFAP, S100B, and STAT3 in the striatum. Results demonstrated that striatal GFAP-immunoreactive cells had an astrocytic appearance under normal conditions, but that dopamine depletion induced a reactive phenotype with obvious morphological changes. The normal striatum also contained S100B and STAT3 expression. S100B-immunoreactive cells were uniform in the striatum, with round bodies and sparse, thin processes. STAT3-immunoreactive cells presented round cell bodies with sparse processes, or were darkly stained with a large cell body. Dopamine deprivation induced by 6-hydroxydopamine significantly enhanced the immunohistochemical positive reaction of S100B and STAT3. Normal striatal astrocytes expressed both S100B and STAT3. Striatal dopamine deprivation increased the number of GFAP/S100B and GFAP/STAT3 double-labeled cells, and increased the protein levels of GFAP, S100B, and STAT3. The present results suggest that morphological changes in astrocytes and changes in expression levels of astrocyte-related proteins are involved in the pathological process of striatal dopamine depletion. The study was approved by Animal Care and Use Committee of Sun Yat-sen University, China (Zhongshan Medical Ethics 2014 No. 23) on September 22, 2014.

Gene Dysfunction Mediates Immune Response to Dopaminergic Degeneration in Parkinson's Disease

Many publications reported that genetic dysfunction mediates abnormal immune responses in the brain, which is important for the development of neurodegenerative diseases, especially for Parkinson's disease (PD). This immune disorder results in subsequent inflammatory reaction, which stimulates microglia or other immune cells to secrete cytokines and chemokines and disturbs the proportion of peripheral blood lymphocyte subsets contributing to dopaminergic (DA) neuron apoptosis. Furthermore, the abnormal immune related signal pathways caused by genetic variants promote chronic inflammation destroying the blood-brain barrier, which allows infiltration of different molecules and blood cells into the central nervous system (CNS) exerting toxicity on DA neurons. As a result, the inflammatory reaction in the CNS accelerates the progression of Parkinson's disease and promotes α-synuclein aggregation and diffusion among DA neurons in the procession of Parkinson's disease. Thus, for disease evaluation, the genetic mediated abnormal immune response in PD may be assessed based on the multiple immune molecules and inflammatory factors, as well as the ratio of lymphocyte subsets from PD patient's peripheral blood as potential biomarkers.