Network Pharmacology to Uncover the Biological Basis of Spleen Qi Deficiency Syndrome and Herbal Treatment

Abstract

Spleen qi deficiency (SQD) syndrome is one of the basic traditional Chinese medicine (TCM) syndromes related to various diseases including chronic inflammation and hypertension and guides the use of many herbal formulae. However, the biological basis of SQD syndrome has not been clearly elucidated due to the lack of appropriate methodologies. Here, we propose a network pharmacology strategy integrating computational, clinical, and experimental investigation to study the biological basis of SQD syndrome. From computational aspects, we used a powerful disease gene prediction algorithm to predict the SQD syndrome biomolecular network which is significantly enriched in biological functions including immune regulation, oxidative stress, and lipid metabolism. From clinical aspects, SQD syndrome is involved in both the local and holistic disorders, that is, the digestive diseases and the whole body's dysfunctions. We, respectively, investigate SQD syndrome-related digestive diseases including chronic gastritis and irritable bowel syndrome and the whole body's dysfunctions such as chronic fatigue syndrome and hypertension. We found innate immune and oxidative stress modules of SQD syndrome biomolecular network dysfunction in chronic gastritis patients and irritable bowel syndrome patients. Lymphocyte modules were downregulated in chronic fatigue syndrome patients and hypertension patients. From experimental aspects, network pharmacology analysis suggested that targets of Radix Astragali and other four herbs commonly used for SQD syndrome are significantly enriched in the SQD syndrome biomolecular network. Experiments further validated that Radix Astragali ingredients promoted immune modules such as macrophage proliferation and lymphocyte proliferation. These findings indicate that the biological basis of SQD syndrome is closely related to insufficient immune response including decreased macrophage activity and reduced lymphocyte proliferation. This study not only demonstrates the potential biological basis of SQD syndrome but also provides a novel strategy for exploring relevant molecular mechanisms of disease-syndrome-herb from the network pharmacology perspective.

Figure 1

A workflow of the network pharmacology strategy for uncovering the biological basis of SQD syndrome and herbal treatment.

Figure 2

The biomolecular network underlying SQD syndrome was constructed based on clinical phenotypes and protein-protein interactions. (a) SQD syndrome phenotype-biomolecule comodule network. (b) SQD syndrome immune biomolecular network (biomolecules with significant enrichment in immune biological processes and pathways are marked, P < 0.05). (c) Validation of the SQD syndrome biomolecular network. (d) The predicted biomolecules of SQD syndrome that are not reported in the literature are upstream or in the same pathway.

Figure 3

The immune molecular network of SQD syndrome covers the DEGs in immune function in chronic gastritis patients and IBS patients. (a) DEGs in chronic gastritis patients with SSDC syndrome and DEGs in IBS patients in the SQD syndrome biomolecular network. (b) The expression of the selected genes in patients with chronic gastritis with SSDC syndrome or SSDH syndrome. (c) The expression of the selected genes in normal individuals and IBS patients. (d) Gene expression related to macrophages in chronic gastritis with SSDC syndrome. (e) DEGs in chronic gastritis with SSDC syndrome in the immune molecular network of SQD syndrome that reduce macrophage function. ^∗P < 0.05, ^∗∗P < 0.01: compared with chronic gastritis patients with SSDH syndrome. (f) Gene expression related to NK cell-mediated bioactivity in IBS patients. (g) DEGs in IBS patients that regulate the NK cell pathway in the SQD syndrome biomolecular network of SQD syndrome. ^∗P < 0.05, ^∗∗P < 0.01: compared with the normal group.

Figure 4

Immune biomolecular network of SQD syndrome contains immune function of SQD syndrome-related diseases. (a) DEGs in CFS or hypertension in the immune molecular network of SQD syndrome. (b) The expression of the selected genes in normal individuals and patients with CFS. (c) The expression of the selected genes in normal individuals and patients with hypertension.

Figure 5

(a) Selected gene expression in normal individuals and CFS patients. (b) DEGs in CFS in the immune molecular network of SQD syndrome that reduced T cell immune function. (c) Selected gene expression in normal individuals and hypertension patients. (d) DEGs in hypertension in the immune molecular network of SQD syndrome that reduced B cell immune function. ^∗P < 0.05, ^∗∗P < 0.01: compared with the normal group.

Figure 6

The immune biomolecular network of SQD syndrome uncovers the mechanisms of action of commonly used herbs for SQD syndrome. (a) Validation of the drugCIPHER-predicted targets of compounds in herbs for SQD syndrome. (b) The predicted targets of herbs for SQD syndrome were significantly enriched in the immune biomolecular network of SQD syndrome compared to herbs for other syndromes. (c) The SQD syndrome immune molecular network covers the predicted targets and the features of herbs for SQD syndrome. (d) The predicted targets of herbs for SQD syndrome are closely related to the immune biomolecular network of SQD syndrome in the topological structure compared to the random situation.

Figure 7

Ingredients in herbs for SQD syndrome may exert immune-enhancing activity related to the immune biomolecular network of SQD syndrome. (a) The predicted targets of the representative ingredients in Radix Astragali may regulate immune function in the macrophage and lymphocyte function modules in the SQD syndrome biomolecular network. (b) Representative ingredients in Radix Astragali improve macrophage proliferation. (c) Astragaloside IV promotes the proliferation of spleen lymphocytes. ^∗∗P < 0.01, ^∗∗∗P < 0.005: compared with the control group.