Single-cell resolution mapping of the immune modulation landscape induced by Chinese herb sanguisorbae radix

Sanguisorbae radix (SR) is employed as a traditional Chinese medicine to boost immune function, partly through elevating megakaryocyte/platelet proportions. Yet, its effects and underlying mechanisms on various types of immune cells remain to be fully explored.

This study investigates the unbiased immunomodulatory effects of SR on human immunity at single-cell resolution.

Here, peripheral blood mononuclear cells (PBMCs) were obtained from the same human subjects pre- and post-SR intervention for single-cell transcriptome analysis, with the biological effects of SR further validated by reverse transcription-quantitative PCR (RT-qPCR) and Western blotting. The chemical composition of SR was identified by ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) and its potential targets were analyzed by molecular docking.

In addition to Mega/Platelets, the findings further reveal that there were fluctuations in immune cell proportions, including increased Dendritic cells (DCs), natural killer cells (NK), CD8⁺T cells and Naïve CD4⁺T cells, and decreased Mast cells, B cells, and Monocytes after taking SR. Notably, SR treatment potentially enhanced cytotoxic CD8⁺T cell activity, as evidenced by elevated cytotoxicity scores and upregulated gene expression of cytotoxic effector molecules including LYZ and GZMK. Furthermore, SR up-regulated the expression of genes related to ribosomes and mitochondria, and inhibited the expression of inflammation-associated genes in T cells, Monocytes, and Mega/Platelets. SR treatment might enhance mitophagy activation, as evidenced by increased LC3-II and decreased SQSTM1 levels, while concurrently suppressed NF-κB signaling through inhibition of P65 and IκB phosphorylation. Moreover, a total of 21 main components in SR were identified by UPLC-MS/MS, which potentially bind to hub genes obtained in the scRNA-seq analysis.

This study first time highlights the transcriptional heterogeneity induced by SR treatment and its distinct modulation of various immune cells in human PBMCs, providing potential for the development of immunomodulatory therapeutics from traditional Chinese medicine.