ObjectiveThis study aims to explore and elucidate the possible mechanism of action of Shakuyakukanzoto (SKT) in improving ulcerative colitis (UC) in mice through regulating energy metabolism and polarization of macrophages. MethodsThe mouse UC model was constructed by administering 3% dextran sulfate sodium salt (DSS), and the mice were treated with SKT intragastrically. In addition, single-cell sequencing and enrichment of metabolic pathways against two datasets, GSE21157 and GSE210415, were conducted first. Second, the extraction and metabolomics of peritoneal macrophages from UC mice were verified. Then, the pathway of differentially abundant metabolite enrichment and the correlation of UC risk were analyzed depending on univariate Mendelian randomization of two samples weighted by standard inverse variance. Finally, the results were verified by qRT-PCR, Western blot, and flow cytometry. ResultsAccording to the HE staining results, SKT can significantly alleviate colon damage caused by DSS. Macrophages, NK cells, T cells, and more than 10 different types of cells, based on single-cell sequencing analysis, are detected in the intestinal wall. In the disease group, we can conclude that the activity of 49 macrophage metabolic pathways, mainly involved in energy metabolism, is significantly upregulated through a comparison of the two datasets. In energy metabolomics, 10 and 18 types of metabolites accompanied by significantly upregulated and downregulated differential expression were identified in the treatment group and the model group, as well as the model group and the blank group, respectively. Meanwhile, these differentially expressed metabolites present an obvious correlation with glycolysis and oxidative phosphorylation. Moreover, it can be inferred that glycolysis and the oxidative phosphorylation-related gene NDUFS1 (OR: 0.56, 95% CI: 0.48-0.98, P=0.000 068) are associated with a reduced risk of UC based on the univariate Mendelian randomization of two samples weighted based on standard inverse variance. By analyzing the difference in transcription levels between the two datasets, the transcription level of NDUFS1 in UC was decreased compared with that in the normal group. The results of qRT-PCR, Western blot, and flow cytometry indicate that SKT can promote the expression of the oxidative phosphorylation protein NDUFS1 in macrophages and inhibit the M1-type polarization of macrophages. Furthermore, knockdown/overexpression of NDUFS1 can affect the effect of SKT on M1-type polarization of macrophages. ConclusionBased on the results of this study, SKT inhibits macrophage polarization toward the M1 phenotype by regulating the level of the oxidatively phosphorylated protein NDUFS1 in macrophages; hence, UC is also relieved in mice. These conclusions not only reveal the therapeutic mechanism of SKT for UC but also provide a new theoretical basis for clinical application.

Ulcerative colitis (UC) is a disease characterized by chronic inflammation of the intestinal mucosa. However, its exact pathogenesis is not fully understood. Zhi Ciweipi (ZCWP), as a traditional Chinese medicine (TCM), has demonstrated suitable anti-inflammatory effects in the treatment of patients with bloody stool and hemorrhoids. However, its therapeutic effects on ulcerative colitis have yet to be investigated in depth. The aim of this study was to investigate the protective effect of the aqueous extract of ZCWP against dextran sulfate sodium salt (DSS)-induced ulcerative colitis in mice and its possible mechanism of action. Successful simulation of ulcerative colitis was achieved by providing mice with drinking water containing 3% DSS. The HE staining results revealed that the aqueous extract of ZCWP could significantly reduce DSS-induced colonic injuries. Transcriptome sequencing analysis identified 10 key inflammation-related genes (IL⁃6, IL⁃1β, CSF2, TNF, IL10, IFN⁃γ, CXCL1, CXCL2, CXCL9, CXCL10), all of which were significantly downregulated (P<0. 05) in response to treatment with the aqueous extract of ZCWP according to qRT-PCR and Western blotting analyses. The immunofluorescence results further indicated that the aqueous extract of ZCWP was able to reduce the DSS-induced increase in the proportion of M1-type macrophages in the colon. Using single-cell sequencing, we thoroughly investigated the signaling relationships between different cell types, which revealed particularly strong communication between M1-type macrophages and fibroblasts. Subsequent qRT-PCR and Western blot analyses verified that the aqueous extract of ZCWP significantly downregulated the expression of DSS-induced fibrosis-related genes in colonic tissues (P<0. 05). In conclusion, the results of this study suggest that the aqueous extract of prepared ZCWP exerts a protective effect against DSS-induced ulcerative colitis by inhibiting M1-type macrophage polarization, downregulating the expression of inflammatory factors, and preventing strong communication between M1-type macrophages and fibroblasts. These findings not only reveal the therapeutic mechanism by which ZCWP aqueous extract treats colitis, but also provide a new theoretical basis for its application in clinical practice.