Alpha-synuclein dynamics bridge Type-I Interferon response and SARS-CoV-2 replication in peripheral cells

BACKGROUND: Increasing evidence suggests a double-faceted role of alpha-synuclein (α-syn) following infection by a variety of viruses, including SARS-CoV-2. Although α-syn accumulation is known to contribute to cell toxicity and the development and/or exacerbation of neuropathological manifestations, it is also a key to sustaining anti-viral innate immunity. Consistently with α-syn aggregation as a hallmark of Parkinson's disease, most studies investigating the biological function of α-syn focused on neural cells, while reports on the role of α-syn in periphery are limited, especially in SARS-CoV-2 infection. RESULTS: Results herein obtained by real time qPCR, immunofluorescence and western blot indicate that α-syn upregulation in peripheral cells occurs as a Type-I Interferon (IFN)-related response against SARS-CoV-2 infection. Noteworthy, this effect mostly involves α-syn multimers, and the dynamic α-syn multimer:monomer ratio. Administration of excess α-syn monomers promoted SARS-CoV-2 replication along with downregulation of IFN-Stimulated Genes (ISGs) in epithelial lung cells, which was associated with reduced α-syn multimers and α-syn multimer:monomer ratio. These effects were prevented by combined administration of IFN-ß, which hindered virus replication and upregulated ISGs, meanwhile increasing both α-syn multimers and α-syn multimer:monomer ratio in the absence of cell toxicity. Finally, in endothelial cells displaying abortive SARS-CoV-2 replication, α-syn multimers, and multimer:monomer ratio were not reduced following exposure to the virus and exogenous α-syn, suggesting that only productive viral infection impairs α-syn multimerization and multimer:monomer equilibrium. CONCLUSIONS: Our study provides novel insights into the biology of α-syn, showing that its dynamic conformations are implicated in the innate immune response against SARS-CoV-2 infection in peripheral cells. In particular, our results suggest that promotion of non-toxic α-syn multimers likely occurs as a Type-I IFN-related biological response which partakes in the suppression of viral replication. Further studies are needed to replicate our findings in neuronal cells as well as animal models, and to ascertain the nature of such α-syn conformations.

Effects of Ligusticum Chuanxiong extract on MPP+-induced SH-SY5Y cells in Parkinson’s syndrome model via miR-23a-3p/SNCA axis / 西安交通大学学报(医学版)

【Objective】 To explore the effects of Ligusticum Chuanxiong extract on MPP+-induced SH-SY5Y cell damage and Parkinson’s syndrome. 【Methods】 1-methyl-4phenylpyridine ion (MPP+) interfered with SH-SY5Y to establish a cell model of elderly Parkinson’s syndrome (SH-SY5Y-MPP+). After intervention with Ligusticum Chuanxiong extract, cell proliferation and apoptosis as well as miR-23a-3p and SNCA expressions were detected. In addition, the changes of SH-SY5Y-MPP+ after regulating the expression of miR-23a-3p and SNCA were observed, and the relationship between miR-23a-3p and SNCA was verified by dual luciferase reporter. 【Results】 The cell proliferation capacity of SH-SY5y-MPP+ was significantly lower than that of SH-SY5Y, while the apoptosis rate was higher than that of SH-SY5Y (P<0.05). Under the intervention of Ligusticum Chuanxiong extract, the proliferation ability of SH-SY5Y-MPP+, and Bcl-2 and SNCA protein increased, the apoptosis rate, miR-23a-3p, and Bax proteins decreased (P<0.05). Both silencing miR-23a-3p and increasing SNCA could promote the proliferation of SH-SY5Y-MPP+ and inhibit apoptosis, while increasing miR-23a-3p and silencing SNCA were the opposite (P<0.05). The online target gene prediction website found that miR-23a-3p and SNCA had complementary sites that could bind, and the dual luciferase reporter enzyme showed that the firefly activity of SNCA-wt was significantly inhibited after the miR-23a-3p mimic sequence was transfected (P<0.05). After increasing miR-23a-3p, the expression of SNCA protein in SH-SY5Y-MPP+ decreased, while silencing miR-23a-3p was the opposite (P<0.05). Rescue experiments showed that the intervention effect of Ligusticum Chuanxiong extract on SH-SY5Y-MPP+ was completely reversed by increasing miR-23a-3p or silent SNCA (P>0.05); the effect of increasing miR-23a-3p on SH-SY5Y-MPP+ increased SNCA reversion (P>0.05). 【Conclusion】 Ligusticum Chuanxiong extract can affect the biological behavior changes of SH-SY5Y induced by MPP+ by regulating the miR-23a-3p/SNCA axis, which may be a new direction for the treatment of elderly Parkinson’s syndrome in the future.

Evaluating the Effect of Iron (II) Chloride Induced Oxidative Stress in SH-SY5Y Cells and Its Role in Upregulation of α-Synuclein Expression

The α-synuclein (SNCA) gene is a pathogenic gene identified in rare familial Parkinson Disease (PD). Recent studies highlight the role of DNA methylation in the pathogenesis of familial and sporadic PD. Hypomethylation in SNCAgene has been associated with increased SNCA gene expression and was observed in post mortem brains of patients with sporadic PD. This study was aimed at evaluating the effect of iron (II) chloride on SH-SY5Y cell models as pertain to cell death caused by oxidative stress, upregulation of SNCA gene expression and reduced SNCA gene methylation. Result obtained from LDH assay showed significant (p<0.05) evidence of cell death in treated cells as compared to the control sample. Analysis for SNCAgene quantification using RT-PCR showed significant increases in fold change. Cells treated with 1000μM of FeCl₂showed the highest fold change of 6.0 while cells treated with 250μM had the lowest fold change of 1.8. In DNA methylation assay using pyrosequencing, cells treated with varying concentrations of FeCl₂showed significant (p<0.05) decrease in DNA methylation. At 250μM, 500μM and 750μM concentrations of FeCl₂, an average mean methylation levels of 1.84%, 1.40% and 1.23% was obtained respectively while cells treated with 1000μM had the lowest average mean methylation level of 1.0%. Thus, the decrease in methylation is linked to the upregulation of the SNCAgene which has been reported to be among the causative factors in the pathogenesis of Parkinson’s disease.

Ausencia de la mutación A53T del gen SNCA en una muestra de pacientes con Enfermedad de Parkinson en el Perú / A53T-SNCA absence in a Peruvian sample of Parkinson's disease patients

Introducción. La enfermedad de Parkinson (EP) es un trastorno neurodegenerativo común, el segundo más frecuente después de la enfermedad de Alzheimer. La mutación A53T en el gen SNCA, fue la primera identificada en asociación con EP. La mayoría de casos de EP en familias con esta mutación provienen de regiones cercanas al lugar del descubrimiento original. Objetivos: Evaluar la presencia de la mutación A53T en el gen SNCA en una muestra peruana de casos con EP de incidencia familiar, esporádicos y controles sanos. Material y Métodos: Se analizaron, mediante la técnica de PCR-RFLP, las muestras de ADN de 34 casos con EP esporádico, 7 casos de EP familiar y 32 individuos control. Resultados: No se encontró la mutación A53T en la muestra analizada, por lo que se infiere que ella estaría confinada a pocas familias de origen caucásico (europeo) asociadas a aquéllas con los casos originalmente descritos. Conclusiones: La mutación A53T no sería un factor causal o primario de EP en los casos evaluados.

Introduction. Parkinson's Disease (PD) is a common neurodegenerative disorder, the second most frequent after Alzheimer's Disease. The A53T mutation in the SNCA gene was the first one identified in association with PD. Most of familial PD cases with this mutation come from regions close to the original discovery site. Objectives: To evaluate the presence of the A53T-SNCA mutation in a Peruvian sample of Parkinson´s Disease cases familial, sporadic and healthy controls. Material and Methods: DNA samples from 34 cases with sporadic PD, 7 cases of familial PD, and 32 control individuals were analyzed by PCR-RFLP. Results: The A53T mutation was not found. This mutation would be confined to a few families of European or Caucasian origin linked to the cases originally described. Conclusions: The A53T mutation would not be the primary causal factor of PD in the evaluated cases

The rs3857059 variant of the SNCA gene is associated with Parkinson's disease in Mexican Mestizos / A variante rs3857059 do gene SNCA é associada à doença de Parkinson em mestiços mexicanos

ABSTRACT Among the candidate genes for Parkinson’s disease (PD), SNCA has replicated association in different populations. Besides other known mutations in the SNCA gene, the rs3857059 variant has also been linked to various neurodegenerative disorders. Therefore, the aim of the present study was to search for association of this variant and sporadic PD in Mexican Mestizo patients. A case-control study was performed including 241 individuals, 106 patients, and 135 healthy controls. Genotyping was performed using real-time PCR. The rs3857059 variant demonstrated an association with PD in Mexican Mestizos (OR = 2.40, CI, 1.1 to 5.1, p = 0.02) under the recessive model. In addition, a gender effect was found for the GG genotype in females (OR = 1.31, CI, 1.01 to 1.7, p = 0.037). This is the first study to confirm an association of the rs3857059 variant with PD and also to show a gender effect. Our data contribute to the elucidation of the link between rs3857059 and susceptibility to PD observed in the Mexican Mestizo population.

RESUMO Entre genes candidatos para a doença de Parkinson (PD), SNCA foi replicado em diferentes populações. Além de outras mutações conhecidas no gene SNCA, a variante rs3857059 também tem sido associada a várias doenças neurodegenerativas. Portanto, o objetivo do presente estudo foi o de procurar variante de associação e PD esporádica em pacientes mestiços mexicanos. Um estudo de caso-controle foi executado, incluindo 241 indivíduos, 106 pacientes e 135 controles saudáveis. A genotipagem foi realizada utilizando PCR em tempo real. A variante rs3857059 se mostrou associada a PD em mexicano-mestiços (OR = 2,40, IC 1,1-5,1, p = 0,02) sob o modelo recessivo. Além disso, um efeito de gênero foi encontrado para o genótipo GG no sexo feminino (OR = 1,31, CI, 1,01-1,7, p = 0,037). Este é o primeiro estudo que confirma associação da variante rs3857059 para a PD e também um efeito de gênero. Nossos dados contribuem para elucidar suscetibilidade à PD observada na população mexicana-mestiça.

Association between polymorphism of α-Synuclein gene and Parkinson's disease of Uygurs nationality in Xinjiang / 中华老年医学杂志

Objective To explore the association between the single-nucleotide polymorphism (SNP) rs3822086 site of the α-Synuclein(SNCA)gene and Parkinson's disease (PD) of Uygurs versus Hans in Xinjiang,and to compare the distribution difference of this polymorphic site between the Uygurs and Hans.Methods The rs3822086 polymorphism was determined by polymerase chainreaction restriction fragment length polymorphism (PCR-RFLP) in 237 patients with idiopathic Parkinson's disease (IPD,including 92 Uygurs and 145 Hans) and 247 health controls (including 103 Uygurs and 144 Hans).Results In the group aged ≥60 years,the T/T,C/T genotypes and T allele frequency were higher in PD group (196 cases) than in control group (196 cases) (25.5％ vs.20.9％,52.0％ vs.44.4％ and 51.5％ vs.43.1％),for genotype:P=0.027,allele:P=0.018.Between the Uygur versus Han nationality population,the T/T,C/T genotype and T allele frequency in the Uygurs were lower than in the Hans (15.4％ vs.30.4 ％,45.6％ vs.50.5％ and 38.2％ vs.55.7％),for genotype:P =0.000,allele:P =0.000.Conclusions The SNP rs3822086 site of SNCA gene may be a potential susceptibility site of IPD patients over the age of 60 years in Xinjiang,and rs3822086C/T + T/T is susceptible genotypes and rs3822086T is susceptible alleles.The distribution of rs3822086 polymorphism of SNCA might have a significant difference between the Xinjiang Uygur and Han populations.