ABSTRACT
Background Paraquat (PQ) is one of the most widely used herbicides in the world and a risk factor for Parkinson's disease (PD), but the mechanisms underlying PD are poorly understood. Single-cell RNA sequencing (scRNA-seq) technology can study cellular heterogeneity at genetic level, providing insights into the pathogenesis of PQ-induced PD. Objective To analyze the brain cell grouping of PQ-infected mice and the biological processes involved in the subpopulation of PD-like changes cells by scRNA-seq, and to provide clues for revealing potential mechanisms of PQ-induced PD-like changes in mouse brains. Methods Six male 6-week-old C57BL/6 mice were randomly divided into a control group and an experimental group, three mice in each group, and were intraperitoneally injected with 0 (saline) and 10.0 mg·kg−1 PD respectively, once every two days, for 10 consecutive injections for modeling. After infection, mouse brains were taken and scRNA-seq was performed. Cell segmentation was performed according to gene expression characteristics of different cell types, PD-related cell subsets were screened by bioinformatics tools, and gene ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), gene set enrichment analysis (GSEA), protein interaction network analysis, and transcription factor prediction were performed on their characteristic genes. Finally, GO and KEGG analyses were performed on the differential genes of PD-associated cell subsets between the PQ-treated group and the control group, and the biological processes in which these genes may participate were analyzed. Results The sequencing data met quality control standards, a total of 55779 cells were obtained, and all cell dimensionality reduction analysis results showed that they could be further divided into 37 clusters, including 5 major cell types. Based on the KEGG analysis of the top 20 characteristic genes of each subpopulation, the specifically expressed Cluster 33 subpopulation (dopaminergic neurons) was screened and found to be significantly associated with PD. The results of GO analysis showed that the biological function of this subpopulation mainly enriched neurotransmitter transport and regulation. The results of GSEA analysis showed that the tyrosine metabolic pathway and the ligand-receptor interaction pathway of neural activity in brain tissues were significantly enriched. The analysis of transcriptional regulatory networks showed that 39 transcription factors were expressed differently. The metabolic pathway of the dopamine neuronal subset, endocytosis, Ras-associated protein 1 (Rap1) signaling pathway, and mitogen-activated protein kinase (MAPK) signaling pathway were all affected by PQ exposure, according to further analysis of its effects on this subpopulation. The GO analysis showed that differential genes were involved in biological processes such as ion transport and synaptic assembly regulation, and were involved in the cellular component formation of cytoplasm and synapses. Conclusion This study has initially mapped the transcriptome of single cells in the mouse brain after PQ exposure, and screened out the specific expression of Cluster 33 subgroup (dopaminergic neurons), which is significantly correlated with PD, and its biological function changes may be one of the mechanisms of PD-like changes in the mouse brain induced by PQ.
ABSTRACT
Objective The aim of this study is to dynamically investigate peripheral blood lymphocyte subsets in fever with thrombocytopenia syndrome (SFTS) patients at different stages,to evaluate the influence of these changes in the infection process.Methods Case-control study was used in the research.Twelveconfirmedthrombocytopeniasyndromevirus ( SFTSV ) infectedpatientswere enrolled.According to SFTS prevention guide issued by Chinese Ministry of Health,these patients were divided into two groups,recovery group and death group.For each group,dynamic profiles of the CD3 + T cells,CD4 + helper T cells,CD8 + cytotoxic T cell and CD3 - CD16 + CD56 + natural killer cells were tested by flow cytometry.Meanwhile, the relationshipsbetween these dynamicchanges and liver function,leukocytes,and platelets were analyzed respectively.Two independent-samples t test was used to compare the difference of the peripheral blood lymphocyte subsets count between the SFTS patients and healthy control.Small sample was analyzed by Mann-Whitney U test.Results In the early stage of infection,Th cells in peripheral blood of recovery group were significantly reduced and Th/Tc ratio was reversed.On day 5,7,9 of post infection,Th cell counts in peripheral blood were (740.9 ± 6.4),(836.2 ± 272.3 ) and ( 1083.6 ± 319.7 ) cells/μl respectively,which were significantly lower than health control ( 1351.4 ± 295.1 ) cells/μl ( t value was -2.883,-4.235,-2.145 respectively,all P ＜0.05).Tc cell counts were significantly more than healthy controls (690.1 ± 194.8) cells/μl through the course,which were ( 1006.3 ±356.5),(1166.4±242.4),(1102.4±245.9),(991.3±205.1) and (886.5±154.5) cells/μl on day 7,9,11,13,15 of the course (t value was 3.312,5.661,4.574,3.874,2.382,all P＜0.05).NK cells were decreased significantly from the ninth day of the course.Associated with abnormal changes of cell subsets,WBC and PLT decreased significantly,and serum ALT,AST,LDH and CK etc.were higher than normal level.With the disease recovery,the abnormality above was gradually improved.In contrast,death cases showed significant decrease in T and Th cells compared with health control (P ＜ 0.05).On day 7,8,9 of the course,the counts of total T cell were (735.9 ± 359.9),(724.9 ± 125.9),(845.3 ± 389.3) cells/μl and the counts of Th cell were ( 533.2 ± 246.9 ),( 532.1 ± 105.7 ),( 551.7 ± 86.9 ) cells/μl,significantly lower than healthy control ( 1727.9 ± 230.2 ) cells/μl and ( 1351.4 ± 295.1 ) cells/μl,with statistically differences (z value was - 2.828, - 2.342,- 2.342 and - 2.828, - 2.342, - 2.342,all P ＜ 0.05 ).On day 7,8,9 of the course,the numbers of NK cell in death group were ( 1141.8 ± 415.5),( 1047.2 ±68.4),( 1276.3 ±545.3) cells/μl,which were significantly more than health group (470.7 ± 242.2) cells/μl,with statistically differences (z value was - 2.180,- 2.335,- 2.258,all P ＜0.05).Conclusions SFTSV infection can induce cell immunity damage.The changes of lymphocyte subsets are associated with clinical classification and prognosis.Significant reduction of T cell and CD4 +cell in peripheral blood are accompanied with significant increase of NK cell,which may be a pivotal indicator of poor prognosis and play an important role in making appropriate strategy in clinical treatment.( Chin J Lab Med,2012,35:826-831 )