Injection of α-syn-98 Aggregates Into the Brain Triggers α-Synuclein Pathology and an Inflammatory Response

The Role of IL-6 in Neurodegenerative Disorders

"Neurodegenerative disorder" is an umbrella term for a group of fatal progressive neurological illnesses characterized by neuronal loss and inflammation. Interleukin-6 (IL-6), a pleiotropic cytokine, significantly affects the activities of nerve cells and plays a pivotal role in neuroinflammation. Furthermore, as high levels of IL-6 have been frequently observed in association with several neurodegenerative disorders, it may potentially be used as a biomarker for the progression and prognosis of these diseases. This review summarizes the production and function of IL-6 as well as its downstream signaling pathways. Moreover, we make a comprehensive review on the roles of IL-6 in neurodegenerative disorders and its potential clinical application.

SNCA correlates with immune infiltration and serves as a prognostic biomarker in lung adenocarcinoma

Background

The SNCA gene is a critical gene in Parkinson’s disease (PD) pathology. Accumulating evidence indicates that SNCA is involved in tumorigenesis; however, the role of SNCA in lung adenocarcinoma (LUAD) remains unclear. This study aimed to explore the potential value of SNCA as a prognostic and diagnostic molecular marker in LUAD.

Methods

In this study, we explored the expression pattern, prognostic value, and promoter methylation status of SNCA in LUAD based on Oncomine, UALCAN, and Kaplan–Meier Plotter. Then, using TIMER, we investigated the correlation between SNCA expression and immune infiltration. And cBioPortal were used to analysis the correlation between SNCA expression and immune checkpoint. The transcriptome data of A549 cells overexpressing SNCA were used to further study the potential immune role of SNCA in LUAD. The effect of SNCA on proliferation of A549 cells were evaluated by CCK-8, EdU and colony formation. Finally, LUAD cell lines treated with 5-aza-dC were used to explore the correlation between increased promoter methylation and downregulated mRNA expression of SNCA.

Results

In general, the expression level of SNCA in LUAD tissue was lower than that in normal tissue, and high expression of SNCA was related to better prognosis.

There were significant positive correlations between SNCA expression and immune infiltrations, including CD8+ T cells, macrophages, neutrophils, dendritic cells, B cells, and CD4+ T cells, and immune checkpoints, suggesting that immune infiltration was one of the reasons for the influence of SNCA on prognosis in LUAD. The transcriptome data of A549 cells overexpressing SNCA were further used to screen the relevant immune-related genes regulated by SNCA. Enrichment analysis confirmed that SNCA participates in the PI3K-AKT signaling pathway and other key tumor signaling pathways and regulates the expression of MAPK3, SRC, PLCG1, and SHC1. Cellular proliferation assay showed that SNCA could inhabit the growth of A549 cells via inhibiting activity of PI3K/AKT/ mTOR pathway. Finally, analysis of the methylation level of SNCA promoter showed that the promoter methylation negatively correlated with mRNA level. The expression of SNCA in LUAD cell lines was significantly upregulated by treatment with 5-aza-dC.

Conclusion

High methylation of SNCA promoter in LUAD is one of the reasons for the downregulation of SNCA mRNA level. Given that SNCA could inhibit the proliferation of A549 cells and correlates with immune infiltrates, it may serve as a prognostic biomarker in LUAD.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-022-09289-7.

α-Synuclein at the Presynaptic Axon Terminal as a Double-Edged Sword

α-synuclein (α-syn) is a presynaptic, lipid-binding protein strongly associated with the neuropathology observed in Parkinson’s disease (PD), dementia with Lewy bodies (DLB), and Alzheimer’s Disease (AD). In normal physiology, α-syn plays a pivotal role in facilitating endocytosis and exocytosis. Interestingly, mutations and modifications of precise α-syn domains interfere with α-syn oligomerization and nucleation that negatively affect presynaptic vesicular dynamics, protein expressions, and mitochondrial profiles. Furthermore, the integration of the α-syn oligomers into the presynaptic membrane results in pore formations, ion influx, and excitotoxicity. Targeted therapies against specific domains of α-syn, including the use of small organic molecules, monoclonal antibodies, and synthetic peptides, are being screened and developed. However, the prospect of an effective α-syn targeted therapy is still plagued by low permeability across the blood–brain barrier (BBB), and poor entry into the presynaptic axon terminals. The present review proposes a modification of current strategies, which includes the use of novel encapsulation technology, such as lipid nanoparticles, to bypass the BBB and deliver such agents into the brain.

Prognostic significance of SNCA and its methylation in bladder cancer

Background

The epidemiological investigation of different cancer types in the global population has reported a decreased risk of bladder cancer (BLCA) in Parkinson’s diseases (PD). SNCA a critical gene in PD pathology have been reported involved in tumorigenesis recently. However, the role of SNCA in BLCA remains unclear. This study aimed to explore the potential value of SNCA as a prognostic diagnostic molecular biomarker in BLCA.

Methods

In this study, we explored the expression pattern, prognostic value and promoter methylation level of SNCA in BLCA by GEPIA2, UALCAN, TCGA, GENT2, GEO and c-BioPortal database. Then, we used LinkedOmics database to obtain the co-expression genes of SNCA for further study by WGCNA. We further investigated the correlations between SNCA expression and six main types of immune cell infiltrations and immune signatures by TIMER. Finally, BLCA cell lines treated with 5-Aza-CdR were used to explore the correlation between increased methylation and downregulated mRNA expression.

Results

SNCA was downregulated in tumor tissues in TCGA-BLCA, GENT2 and GEO, which was validated in our cohort by qRT-PCR and immunohistochemistry. SNCA was confirmed as an independent predictor of poor overall survival (OS). LinkedOmics analysis suggested that SNCA regulates cell adhesion molecules, cytokine–cytokine receptor interaction, and complement and coagulation cascades. Twenty-two co-expression gene modules were constructed by WGCNA, and most of them were significantly associated with OS and disease-free survival (DFS). Six key genes (CNTN1, DACT3, MYLK1, PDE2A, RBM24, and ST6GALNAC3) screened also significantly correlated with prognosis. There were significant correlations between SNCA expression and immune infiltrations, especially T cell, suggesting that immune infiltration was one of the reasons for the influence of SNCA on prognosis in BLCA. Analysis by ULACAN and c-BioPortal showed that the promoter methylation of SNCA negatively correlated with its mRNA level. Furthermore, BLCA cell treatment with 5-Aza-CdR revealed that SNCA expression levels were upregulated with decreased methylation.

Conclusion

Our research showed that SNCA was downregulated in BLCA and negatively correlation with DNA methylation. High SNCA expression was confirmed as an independent risk for prognosis. SNCA probably plays an important role in the infiltration of immune cells, especially with T cells. Thus, SNCA may be a promising prognostic biomarker in BLCA patients.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-022-09411-9.

SARS-CoV-2 Proteins Interact with Alpha Synuclein and Induce Lewy Body-like Pathology In Vitro

Growing cases of patients reported have shown a potential relationship between (severe acute respiratory syndrome coronavirus 2) SARS-CoV-2 infection and Parkinson’s disease (PD). However, it is unclear whether there is a molecular link between these two diseases. Alpha-synuclein (α-Syn), an aggregation-prone protein, is considered a crucial factor in PD pathology. In this study, bioinformatics analysis confirmed favorable binding affinity between α-Syn and SARS-CoV-2 spike (S) protein and nucleocapsid (N) protein, and direct interactions were further verified in HEK293 cells. The expression of α-Syn was upregulated and its aggregation was accelerated by S protein and N protein. It was noticed that SARS-CoV-2 proteins caused Lewy-like pathology in the presence of α-Syn overexpression. By confirming that SARS-CoV-2 proteins directly interact with α-Syn, our study offered new insights into the mechanism underlying the development of PD on the background of COVID-19.

Common aspects between glaucoma and brain neurodegeneration

Neurodegeneration can be defined as progressive cell damage to nervous system cells, and more specifically to neurons, which involves morphologic alterations and progressive loss of function until cell death. Glaucoma exhibits many aspects of neurodegenerative disease. This review examines the pathogenesis of glaucoma, comparing it with that of Alzheimer's disease (AD) and Parkinson's disease (PD), highlighting their common features. Indeed, in all three diseases there are not only the same types of pathogenic events, but also similarities of temporal cadences that determine neuronal damage. All three age-related illnesses have oxidative damage and mitochondrial dysfunction as the first pathogenic steps. The consequence of these alterations is the death of visual neurons in glaucoma, cognitive neurons in AD and regulatory motor neurons (substantia nigra) in PD. The study of these common pathogenic events (oxidative stress, mitochondrial dysfunction, protein degradation, apoptosis and autophagy) leads us to consider common therapeutic strategies for the treatment and prevention of these diseases. Also, examination of the genetic aspects of the pathways involved in neurodegenerative processes plays a key role in shedding light on the details of pathogenesis and can suggest new treatments. This review discusses the common molecular aspects involved in these three oxidative-stress and age-related diseases.