Single-cell transcriptomics reveals immune infiltrate in sepsis.

Area of Science:

• Immunology
• Bioinformatics
• Genomics

Background:

• Sepsis pathogenesis involves complex immune cell interactions and microenvironment alterations.
• Understanding immune cell infiltration is critical for sepsis progression and treatment.

Purpose of the Study:

• To identify key genes (hub genes) associated with immune cell infiltration in sepsis.
• To explore the role of these hub genes in sepsis immune responses.

Main Methods:

• Utilized GEO database and R packages (GEOquery, limma, Seurat) for differential gene expression analysis.
• Applied t-distributed stochastic neighbor embedding (t-SNE) for immune cell clustering.
• Performed Gene Set Enrichment Analysis (GSEA), Gene Ontology (GO), and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses.
• Screened hub genes using Maximal Clique Centrality, Maximum neighborhood component, and Density of Maximum Neighborhood Component algorithms.
• Validated findings through in vivo animal experiments including Western blotting, flow cytometry, Elisa, and qPCR.

Main Results:

• Identified 61 differentially expressed genes (DEGs) between sepsis and normal samples.
• Clustered immune cells including T cells, NK cells, monocytes, megakaryocytes, DCs, and B cells.
• GSEA revealed enrichment in pathways like Neutrophil Degranulation and T Cell Activation.
• Seven hub genes (CD28, CD3D, CD2, CD4, IL7R, LCK, CD3E) were identified.
• Six hub genes (CD28, CD3D, CD4, IL7R, LCK, CD3E) exhibited lower expression in sepsis samples.
• Significant differences in immune cell populations were observed between sepsis and control groups.

Conclusions:

• Seven hub genes are significantly associated with immune cell infiltration in sepsis.
• Reduced expression of specific hub genes in sepsis suggests their potential role in immune dysfunction.
• These findings provide insights into sepsis-associated immune dysregulation and potential therapeutic targets.