Exploring Intrinsic Disorder in Human Synucleins and Associated Proteins.

In this work, we explored the intrinsic disorder status of the three members of the synuclein family of proteins-α-, ß-, and γ-synucleins-and showed that although all three human synucleins are highly disordered, the highest levels of disorder are observed in γ-synuclein. Our analysis of the peculiarities of the amino acid sequences and modeled 3D structures of the human synuclein family members revealed that the pathological mutations A30P, E46K, H50Q, A53T, and A53E associated with the early onset of Parkinson's disease caused some increase in the local disorder propensity of human α-synuclein. A comparative sequence-based analysis of the synuclein proteins from various evolutionary distant species and evaluation of their levels of intrinsic disorder using a set of commonly used bioinformatics tools revealed that, irrespective of their origin, all members of the synuclein family analyzed in this study were predicted to be highly disordered proteins, indicating that their intrinsically disordered nature represents an evolutionary conserved and therefore functionally important feature. A detailed functional disorder analysis of the proteins in the interactomes of the human synuclein family members utilizing a set of commonly used disorder analysis tools showed that the human α-synuclein interactome has relatively higher levels of intrinsic disorder as compared with the interactomes of human ß- and γ- synucleins and revealed that, relative to the ß- and γ-synuclein interactomes, α-synuclein interactors are involved in a much broader spectrum of highly diversified functional pathways. Although proteins interacting with three human synucleins were characterized by highly diversified functionalities, this analysis also revealed that the interactors of three human synucleins were involved in three common functional pathways, such as the synaptic vesicle cycle, serotonergic synapse, and retrograde endocannabinoid signaling. Taken together, these observations highlight the critical importance of the intrinsic disorder of human synucleins and their interactors in various neuronal processes.

Upregulation of γ-synuclein in the prefrontal cortex and hippocampus following dopamine depletion: A study using the striatal 6-hydroxydopamine hemiparkinsonian rat model.

Synucleins, including α-synuclein (α-syn), ß-syn, and γ-syn, have been implicated in various synucleinopathies, notably Parkinson's disease (PD), which has generated increased interest in understanding their roles. Although α-syn and ß-syn have contrasting neuropathological consequences, the precise role of γ-syn remains unclear. This study validated non-motor symptoms, specifically anxiety-like behavior, along with the degradation of dopaminergic (DAergic) neurons in the nigrostriatal system and DAergic neurites in the prefrontal cortex and hippocampus of rats infused with striatal 6-hydroxydopamine (6-OHDA). Our study further investigated the alterations in γ-syn expression levels in the prefrontal cortices and hippocampi of these 6-OHDA-treated rats, aiming to establish foundational insights into the neuropathophysiology of DA depletion, a central feature of PD. Our findings revealed a significant increase in the expression of γ-syn mRNA and protein in these brain regions, in contrast to unaltered α- and ß-syn expression levels. This suggests a distinct role of γ-syn within the neurobiological milieu under conditions of DA deficiency. Overall, our data shed light on the neurobiological changes observed in the hemiparkinsonian rat model induced with 6-OHDA, underscoring the potential significance of γ-syn in PD pathology.

Cyclic-NDGA Effectively Inhibits Human γ-Synuclein Fibrillation, Forms Nontoxic Off-Pathway Species, and Disintegrates Preformed Mature Fibrils.

Parkinson's disease arises from protein misfolding, aggregation, and fibrillation and is characterized by LB (Lewy body) deposits, which contain the protein α-synuclein (α-syn) as their major component. Another synuclein, γ-synuclein (γ-syn), coexists with α-syn in Lewy bodies and is also implicated in various types of cancers, especially breast cancer. It is known to seed α-syn fibrillation after its oxidation at methionine residue, thereby contributing in synucleinopathy. Despite its involvement in synucleinopathy, the search for small molecule inhibitors and modulators of γ-syn fibrillation remains largely unexplored. This work reveals the modulatory properties of cyclic-nordihydroguaiaretic acid (cNDGA), a natural polyphenol, on the structural and aggregational properties of human γ-syn employing various biophysical and structural tools, namely, thioflavin T (ThT) fluorescence, Rayleigh light scattering, 8-anilinonaphthalene-1-sulfonic acid binding, far-UV circular dichroism (CD), Fourier transform infrared spectroscopy (FTIR) spectroscopy, atomic force microscopy, ITC, molecular docking, and MTT-toxicity assay. cNDGA was observed to modulate the fibrillation of γ-syn to form off-pathway amorphous species that are nontoxic in nature at as low as 75 µM concentration. The modulation is dependent on oxidizing conditions, with cNDGA weakly interacting (Kd ∼10-5 M) with the residues at the N-terminal of γ-syn protein as investigated by isothermal titration calorimetry and molecular docking, respectively. Increasing cNDGA concentration results in an increased recovery of monomeric γ-syn as shown by sodium dodecyl sulfate and native-polyacrylamide gel electrophoresis. The retention of native structural properties of γ-syn in the presence of cNDGA was further confirmed by far-UV CD and FTIR. In addition, cNDGA is most effective in suppression of fibrillation when added at the beginning of the fibrillation kinetics and is also capable of disintegrating the preformed mature fibrils. These findings could, therefore, pave the ways for further exploring cNDGA as a potential therapeutic against γ-synucleinopathies.

Substitution of Met-38 to Ile in γ-synuclein found in two patients with amyotrophic lateral sclerosis induces aggregation into amyloid.

α-, ß-, and γ-Synuclein are intrinsically disordered proteins implicated in physiological processes in the nervous system of vertebrates. α-synuclein (αSyn) is the amyloidogenic protein associated with Parkinson's disease and certain other neurodegenerative disorders. Intensive research has focused on the mechanisms that cause αSyn to form amyloid structures, identifying its NAC region as being necessary and sufficient for amyloid assembly. Recent work has shown that a 7-residue sequence (P1) is necessary for αSyn amyloid formation. Although γ-synuclein (γSyn) is 55% identical in sequence to αSyn and its pathological deposits are also observed in association with neurodegenerative conditions, γSyn is resilient to amyloid formation in vitro. Here, we report a rare single nucleotide polymorphism (SNP) in the SNCG gene encoding γSyn, found in two patients with amyotrophic lateral sclerosis (ALS). The SNP results in the substitution of Met38 with Ile in the P1 region of the protein. These individuals also had a second, common and nonpathological, SNP in SNCG resulting in the substitution of Glu110 with Val. In vitro studies demonstrate that the Ile38 variant accelerates amyloid fibril assembly. Contrastingly, Val110 retards fibril assembly and mitigates the effect of Ile38. Substitution of residue 38 with Leu had little effect, while Val retards, and Ala increases the rate of amyloid formation. Ile38 γSyn also results in the formation of γSyn-containing inclusions in cells. The results show how a single point substitution can enhance amyloid formation of γSyn and highlight the P1 region in driving amyloid formation in another synuclein family member.

Upregulation of Parkinson's disease-associated protein alpha-synuclein suppresses tumorigenesis via interaction with mGluR5 and gamma-synuclein in liver cancer.

Numerous epidemiological studies suggest a link between Parkinson's disease (PD) and cancer, indicating that PD-associated proteins may mediate the development of cancer. Here, we investigated a potential role of PD-associated protein α-synuclein in regulating liver cancer progression in vivo and in vitro. We found the negative correlation of α-synuclein with metabotropic glutamate receptor 5 (mGluR5) and γ-synuclein by analyzing the data from The Cancer Genome Atlas database, liver cancer patients and hepatoma cells with overexpressed α-synuclein. Moreover, upregulated α-synuclein suppressed the growth, migration, and invasion. α-synuclein was found to associate with mGluR5 and γ-synuclein, and the truncated N-terminal of α-synuclein was essential for the interaction. Furthermore, overexpressed α-synuclein exerted the inhibitory effect on hepatoma cells through the degradation of mGluR5 and γ-synuclein via α-synuclein-dependent autophagy-lysosomal pathway (ALP). Consistently, in vivo experiments with rotenone-induced rat model of PD also confirmed that, upregulated α-synuclein in liver cancer tissues through targeting on mGluR5/α-synuclein/γ-synuclein complex inhibited tumorigenesis involving in ALP-dependent degradation of mGluR5 and γ-synuclein. These findings give an insight into an important role of PD-associated protein α-synuclein accompanied by the complex of mGluR5/α-synuclein/γ-synuclein in distant communications between PD and liver cancer, and provide a new strategy in therapeutics for the treatment of liver cancer.

The Synucleins and the Astrocyte.

Synucleins consist of three proteins exclusively expressed in vertebrates. α-Synuclein (αS) has been identified as the main proteinaceous aggregate in Lewy bodies, a pathological hallmark of many neurodegenerative diseases. Less is understood about ß-synuclein (ßS) and γ-synuclein (γS), although it is known ßS can interact with αS in vivo to inhibit aggregation. Likewise, both γS and ßS can inhibit αS's propensity to aggregate in vitro. In the central nervous system, ßS and αS, and to a lesser extent γS, are highly expressed in the neural presynaptic terminal, although they are not strictly located there, and emerging data have shown a more complex expression profile. Synapse loss and astrocyte atrophy are early aspects of degenerative diseases of the brain and correlate with disease progression. Synucleins appear to be involved in synaptic transmission, and astrocytes coordinate and organize synaptic function, with excess αS degraded by astrocytes and microglia adjacent to the synapse. ßS and γS have also been observed in the astrocyte and may provide beneficial roles. The astrocytic responsibility for degradation of αS as well as emerging evidence on possible astrocytic functions of ßS and γS, warrant closer inspection on astrocyte-synuclein interactions at the synapse.

Synucleins: New Data on Misfolding, Aggregation and Role in Diseases.

The synucleins are a family of natively unfolded (or intrinsically unstructured) proteins consisting of α-, ß-, and γ-synuclein involved in neurodegenerative diseases and cancer. The current number of publications on synucleins has exceeded 16.000. They remain the subject of constant interest for over 35 years. Two reasons explain this unchanging attention: synuclein's association with several severe human diseases and the lack of understanding of the functional roles under normal physiological conditions. We analyzed recent publications to look at the main trends and developments in synuclein research and discuss possible future directions. Traditional areas of peak research interest which still remain high among last year's publications are comparative studies of structural features as well as functional research on of three members of the synuclein family. Another popular research topic in the area is a mechanism of α-synuclein accumulation, aggregation, and fibrillation. Exciting fast-growing area of recent research is α-synuclein and epigenetics. We do not present here a broad and comprehensive review of all directions of studies but summarize only the most significant recent findings relevant to these topics and outline potential future directions.

Up and Down γ-Synuclein Transcription in Dopamine Neurons Translates into Changes in Dopamine Neurotransmission and Behavioral Performance in Mice.

The synuclein family consists of α-, ß-, and γ-Synuclein (α-Syn, ß-Syn, and γ-Syn) expressed in the neurons and concentrated in synaptic terminals. While α-Syn is at the center of interest due to its implication in the pathogenesis of Parkinson's disease (PD) and other synucleinopathies, limited information exists on the other members. The current study aimed at investigating the biological role of γ-Syn controlling the midbrain dopamine (DA) function. We generated two different mouse models with: (i) γ-Syn overexpression induced by an adeno-associated viral vector and (ii) γ-Syn knockdown induced by a ligand-conjugated antisense oligonucleotide, in order to modify the endogenous γ-Syn transcription levels in midbrain DA neurons. The progressive overexpression of γ-Syn decreased DA neurotransmission in the nigrostriatal and mesocortical pathways. In parallel, mice evoked motor deficits in the rotarod and impaired cognitive performance as assessed by novel object recognition, passive avoidance, and Morris water maze tests. Conversely, acute γ-Syn knockdown selectively in DA neurons facilitated forebrain DA neurotransmission. Importantly, modifications in γ-Syn expression did not induce the loss of DA neurons or changes in α-Syn expression. Collectively, our data strongly suggest that DA release/re-uptake processes in the nigrostriatal and mesocortical pathways are partially dependent on substantia nigra pars compacta /ventral tegmental area (SNc/VTA) γ-Syn transcription levels, and are linked to modulation of DA transporter function, similar to α-Syn.

Gamma-Synuclein Dysfunction Causes Autoantibody Formation in Glaucoma Patients and Dysregulation of Intraocular Pressure in Mice.

Dysregulation of intraocular pressure (IOP) is one of the main risk factors for glaucoma. γ-synuclein is a member of the synuclein family of widely expressed synaptic proteins within the central nervous system that are implicated in certain types of neurodegeneration. γ-synuclein expression and localization changes in the retina and optic nerve of patients with glaucoma. However, the mechanisms by which γ-synuclein could contribute to glaucoma are poorly understood. We assessed the presence of autoantibodies to γ-synuclein in the blood serum of patients with primary open-angle glaucoma (POAG) by immunoblotting. A positive reaction was detected for five out of 25 patients (20%) with POAG. Autoantibodies to γ-synuclein were not detected in a group of patients without glaucoma. We studied the dynamics of IOP in response to IOP regulators in knockout mice (γ-KO) to understand a possible link between γ-synuclein dysfunction and glaucoma-related pathophysiological changes. The most prominent decrease of IOP in γ-KO mice was observed after the instillation of 1% phenylephrine and 10% dopamine. The total protein concentration in tear fluid of γ-KO mice was approximately two times higher than that of wild-type mice, and the activity of neurodegeneration-linked protein α2-macroglobulin was reduced. Therefore, γ-synuclein dysfunction contributes to pathological processes in glaucoma, including dysregulation of IOP.

A microRNA Cluster Controls Fat Cell Differentiation and Adipose Tissue Expansion By Regulating SNCG.

The H19X-encoded miR-424(322)/503 cluster regulates multiple cellular functions. Here, it is reported for the first time that it is also a critical linchpin of fat mass expansion. Deletion of this miRNA cluster in mice results in obesity, while increasing the pool of early adipocyte progenitors and hypertrophied adipocytes. Complementary loss and gain of function experiments and RNA sequencing demonstrate that miR-424(322)/503 regulates a conserved genetic program involved in the differentiation and commitment of white adipocytes. Mechanistically, it is demonstrated that miR-424(322)/503 targets γ-Synuclein (SNCG), a factor that mediates this program rearrangement by controlling metabolic functions in fat cells, allowing adipocyte differentiation and adipose tissue enlargement. Accordingly, diminished miR-424(322) in mice and obese humans co-segregate with increased SNCG in fat and peripheral blood as mutually exclusive features of obesity, being normalized upon weight loss. The data unveil a previously unknown regulatory mechanism of fat mass expansion tightly controlled by the miR-424(322)/503 through SNCG.

γ-Synuclein is Closely Involved in Autophagy that Protects Colon Cancer Cell from Endoplasmic Reticulum Stress.

BACKGROUND: In previous studies, we provided evidence suggesting the involvement of γ-synuclein in growth, invasion, and metastasis of colon cancer cells in vitro and in vivo. Among γ-synuclein downstream genes, the microtubule-associated protein 1 Light Chain 3 (LC3), an autophagy gene, was screened by gene expression profile chip analysis. OBJECTIVE: We planned to investigate the functional effects of γ-synuclein on autophagy induced by ER stress in colon cancer cells. METHODS: We investigated the functional effects of γ-synuclein on autophagy and apoptosis induced by Thapsigargin (TG), ER stress-inducing agent, in colon cancer cell lines using immunofluorescence staining, RT-PCR, western blot, CCK8 test, flow cytometry analysis, and transmission electron microscopy. To further determine how γ-synuclein regulated autophagy and apoptosis, PD98059 (ERK inhibitor), SP600125 (ERK inhibitor), anisomycin (JNK activator), and c-Jun siRNA were used respectively in γ-synuclein siRNA transfected HCT116 cells. Then, autophagy proteins, apoptosis proteins, and pathway proteins were detected by western blot analysis. The expression of autophagy genes was assessed by RT-PCR. RESULTS: Our data showed that ER stress-induced colon cancer cells autophagy mainly in the early stage (0-24h) and apoptosis mainly in the late stage (24-48h). ER stress up-regulated γ-synuclein gene and protein expression in colon cancer cells, accompanied by autophagy. γ-synuclein protected HCT116 cells by enhancing autophagy in the early stage (0-24h) through activation of ERK and JNK pathway and inhibiting apoptosis in the late stage (24-48h) through inhibition of the JNK pathway. γ-synuclein could promote autophagy via the JNK pathway activation of ATG genes, LC3, Beclin 1, and ATG7. γ-synuclein may play a role in the transition between autophagy and apoptosis in our model. CONCLUSION: Overall, we provided the first experimental evidence to show that γ-synuclein may play an important role in autophagy that protects colon cancer cells from ER stress. Therefore, our data suggest a new molecular mechanism for γ-synuclein-mediated CRC progression.

[shRNA-Mediated Suppression of γ-Synuclein Leading to Downregulation of p38/ERK/JNK Phosphorylation and Cell Cycle Arrest in Endometrial Cancer Cells].

In this study, we explored the effects of treating human endometrial cancer cells with γ-synuclein-specific short hairpin RNA (shRNA) and elucidated the associated mechanisms in vitro and in vivo through the p38, extracellular signal-regulated kinase (ERK), and c-Jun N-terminal kinase (JNK) signaling pathways. Cell proliferation and migration were assessed using CCK8, Transwell, and scratch wound healing assays. Flow cytometry and laser scanning confocal microscopy were used to detect cell cycle changes. Relative levels of phosphorylated and non-phosphorylated (p) p38, ERK1/2 and JNK1/2/3 were determined in vitro and in vivo using simple western blotting assays. Cell proliferation in the experimental group decreased significantly and cells transfected with shRNA showed reduced migration rates (P < 0.05). p-p38, p-ERK1/2, and p-JNK1/2/3 levels were downregulated in the experimental group in vitro and in vivo. Tumor volumes and weights in the experimental group were significantly lower (P < 0.05). Tumor formation time in the negative control group was significantly shorter (P < 0.05). Flow cytometry showed that the number of cells in the G1 and mitotic phases increased and that in the S phase decreased after SNCG silencing (P < 0.05). Confocal microscopy showed that the percentage of cells in the mitotic phase increased after SNCG gene silencing (P < 0.05). We conclude that shRNA-mediated suppression of γ-synuclein decreased the proliferation, migration, and tumorigenicity of endometrial cancer cells via downregulation of p38, ERK, and JNK phosphorylation. High SNCG expression is closely related to the growth cycle of endometrial cancer cells.

Amyloid Evolvability and Cancer.

p53 and γ-synuclein are two major regulators of cancer pathogenesis that have the propensity to form amyloid-like fibrils reminiscent of those in neurodegenerative diseases. Here we propose that fibril formation by these amyloidogenic molecules reflects evolvability, an acquired epigenetic inheritance that may be involved in cancer proliferation, drug resistance, and metastasis.

Suppression, disaggregation, and modulation of γ-Synuclein fibrillation pathway by green tea polyphenol EGCG.

Oligomerization of γ-Synuclein is known to have implications for both neurodegeneration and cancer. Although it is known to co-exist with the fibrillar deposits of α-Synuclein (Lewy bodies), a hallmark in Parkinson's disease (PD), the effect of potential therapeutic modulators on the fibrillation pathway of γ-Syn remains unexplored. By a combined use of various biophysical tools and cytotoxicity assays we demonstrate that the flavonoid epigallocatechin-3-gallate (EGCG) significantly suppresses γ-Syn fibrillation by affecting its nucleation and binds with the unstructured, nucleus forming oligomers of γ-Syn to modulate the pathway to form α-helical containing higher-order oligomers (~158 kDa and ~ 670 kDa) that are SDS-resistant and conformationally restrained in nature. Seeding studies reveal that these oligomers although "on-pathway" in nature, are kinetically retarded and rate-limiting species that slows down fibril elongation. We observe that EGCG also disaggregates the protofibrils and mature γ-Syn fibrils into similar SDS-resistant oligomers. Steady-state and time-resolved fluorescence spectroscopy and isothermal titration calorimetry (ITC) reveal a weak non-covalent interaction between EGCG and γ-Syn with the dissociation constant in the mM range (Kd ~ 2-10 mM). Interestingly, while EGCG-generated oligomers completely rescue the breast cancer (MCF-7) cells from γ-Syn toxicity, it reduces the viability of neuroblastoma (SH-SY5Y) cells. However, the disaggregated oligomers of γ-Syn are more toxic than the disaggregated fibrils for MCF-7cells. These findings throw light on EGCG-mediated modulation of γ-Syn fibrillation and suggest that investigation on the effects of such modulators on γ-Syn fibrillation is critical in identifying effective therapeutic strategies using small molecule modulators of synucleopathies.

Effect of polyols on the structure and aggregation of recombinant human γ-Synuclein, an intrinsically disordered protein.

Polyol osmolytes accumulated in cells under stress are known to promote stability in globular proteins with respect to their increasing hydroxyl groups but their effect on the structure, stability and aggregation of intrinsically disordered proteins (IDPs) is still elusive. The lack of a natively folded structure in intrinsically disordered proteins under physiological conditions results in their aggregation and fibrillation that gives rise to a number of diseases. We have investigated the effect of a series of polyols, ethylene glycol (EG), glycerol, erythritol, xylitol and sorbitol on the fibrillation pathway of recombinant human γ-Synuclein, used as a model, for an IDP known to form fibrils that play a role in neurodegeneration and cancer. With an increase in the number of -OH groups in polyols except EG, we observe a decrease in lag time for fibrillation at equimolar concentrations, suggesting stronger preferential exclusion of polyols that promotes γ-Syn self-association and oligomerization. The polyols act early during nucleation and their diverse effect on the rate of fibrillation suggests the role of favourable solvent-side chain interactions. With increasing -OH group, polyols stabilize the natively unfolded conformation of γ-Syn under non-fibrillating conditions and delay the structural transition to characteristic ß-sheet structure by forming an α-helical intermediate during fibrillation. The results, overall suggest that the effect of osmolytes on IDPs is much more complex than their effect on globular protein stability and aggregation and a fine balance between the dominant unfavourable osmolyte-peptide backbone and favourable osmolyte-charged side chain interactions would govern their stability and aggregation properties.

Evolvability of Amyloidogenic Proteins in Human Brain.

Currently, the physiological roles of amyloidogenic proteins (APs) in human brain, such as amyloid-ß and α-synuclein, are elusive. Given that many APs arose by gene duplication and have been resistant against the pressures of natural selection, APs may be associated with some functions that are advantageous for survival of offspring. Nonetheless, evolvability is the sole physiological quality of APs that has been characterized in microorganisms such as yeast. Since yeast and human brain may share similar strategies in coping with diverse range of critical environmental stresses, the objective of this paper was to discuss the potential role of evolvability of APs in aging-associated neurodegenerative disorders, including Alzheimer's disease and Parkinson's disease. Given the heterogeneity of APs in terms of structure and cytotoxicity, it is argued that APs might be involved in preconditioning against diverse stresses in human brain. It is further speculated that these stress-related APs, most likely protofibrillar forms, might be transmitted to offspring via the germline, conferring preconditioning against forthcoming stresses. Thus, APs might represent a vehicle for the inheritance of the acquired characteristics against environmental stresses. Curiously, such a characteristic of APs is reminiscent of Charles Darwin's 'gemmules', imagined molecules of heritability described in his pangenesis theory. We propose that evolvability might be a physiological function of APs during the reproductive stage and neurodegenerative diseases could be a by-product effect manifested later in aging. Collectively, our evolvability hypothesis may play a complementary role in the pathophysiology of APs with the conventional amyloid cascade hypothesis.

Gamma-synuclein binds to AKT and promotes cancer cell survival and proliferation.

Hyperactivation of AKT plays a critical role in the survival and proliferation of cancer cells. However, the molecular mechanisms underlying AKT activation remain elusive. Here, we tested the effect of γ-synuclein, a member of the synuclein family of proteins, on the activation of AKT. We show that the expression level of γ-synuclein is increased in non-small cell lung cancer (NSCLC) tissues. γ-Synuclein binds to the protein kinase domain of AKT and promotes its phosphorylation. Overexpression of γ-synuclein in H157 cells enhances cell proliferation and protects the cells from staurosporine-induced cytotoxicity. Knockdown of γ-synuclein attenuates AKT activation and cell proliferation induced by epidermal growth factor. The effect of γ-synuclein is abolished when AKT is depleted. Thus, γ-synuclein promotes cell survival and proliferation via activating AKT and may play a causal role in the pathogenesis of NSCLC.

Neuroprotective effects of antibodies on retinal ganglion cells in an adolescent retina organ culture.

Glaucoma, a neurodegenerative disease, is characterized by a progressive loss of retinal ganglion cells (rgc). Up- and down-regulated autoantibody immunoreactivities in glaucoma patients have been demonstrated. Previous studies showed protective effects of down-regulated antibodies [gamma (γ)-synuclein and glial fibrillary acidic protein [GFAP]) on neuroretinal cells. The aim of this study was to test these protective antibody effects on rgc in an organ culture model and to get a better understanding of cell-cell interactions of the retina in the context of the protective effect. We used an adolescent retinal organ culture (pig) with an incubation time of up to 4 days. Retinal explants were incubated with different antibodies for 24 h (anti-GFAP, anti-γ-synuclein and anti-myoglobin antibody as a control). Brn3a and TUNEL staining were performed. We also conducted glutamine synthetase staining and quantification of the retinal explants. Mass spectrometry analyses were performed as well as protein analyses via microarray. We detected a continuous decrease of rgc/mm in the retinal explants throughout the 4 days of incubation with increased TUNEL rgc staining. Immunohistochemical analyses showed a protective effect of anti-γ-synuclein (increased rgc/mm of 41%) and anti-GFAP antibodies (increased rgc/mm of 37%). Mass spectrometric, microarray and immunohistochemical analyses demonstrated Müller cell involvement and decreased endoplasmic reticulum stress response in the antibody-treated retinae. We could detect that the tested antibodies have a protective effect on rgc which seems to be the result of reduced stress levels in the retina as well as a shift of glutamine synthetase localization in the endfeet of the Müller cells towards the inner retinal layer. Loss of retinal ganglion cells (rgc) in glaucoma leads to blindness. Several antibodies are down-regulated in glaucoma patients. Our aim was to test if these antibodies have a protective effect of rgc in a retinal organ culture. This could be shown with an increase of rgc numbers. This effect results through reduced stress levels and the shift of glutamine synthetase localization.

Expression of γ-Synuclein in Bladder Carcinoma: A Possible Marker for Prognosis.

AIM: To investigate if γ-synuclein (SNCG) could be used as a bladder cancer (BC) marker to predict prognosis of BC. PATIENTS AND METHODS: Medical records of 140 patients with BC (January, 2006 to December, 2009) were retrospectively reviewed. SNCG expression level was examined by immunohistological staining. The patients' survival rate was calculated by the Kaplan-Meier method. Cox proportional regression model was used to identify independent predictors for BC. RESULTS: Overexpression of SNCG was detected in BC tissues and the expression level of SNCG strongly positively correlated with BC recurrence. However, no correlation was found between SNCG level and tumor stage or survival rate. CONCLUSION: SNCG is a good marker to predict recurrence of BC, but not a reliable marker for staging or prediction of survival rate.

The impairment of learning and memory and synaptic loss in mouse after chronic nitrite exposure.

The objective of this study is to understand the impairment of learning and memory in mouse after chronic nitrite exposure. The animal model of nitrite exposure in mouse was created with the daily intubation of nitrite in adult healthy male mice for 3 months. Furthermore, the mouse's learning and memory abilities were tested with Morris water maze, and the expression of Synaptophysin and γ-Synuclein was visualized with immunocytochemistry and Western blot. Our results showed that nitrite exposure significantly prolonged the escape latency period (ELP) and decreased the values of the frequency across platform (FAP) as well as the accumulative time in target quadrant (ATITQ) compared to control, in dose-dependent manner. In addition, after nitrite exposure, synaptophysin (SYN) positive buttons in the visual cortex was reduced, in contrast the increase of γ-synuclein positive cells. The results above were supported by Western blot as well. We conclude that nitrite exposure could lead to a decline in mice's learning and memory. The overexpression of γ-synuclein contributed to the synaptic loss, which is most likely the cause of learning and memory impairment. © 2015 Wiley Periodicals, Inc. Environ Toxicol 31: 1720-1730, 2016.