Sishen pills inhibit inflammatory dendritic cell differentiation via miR-505-3p mediated E-cadherin downregulation in ulcerative colitis.

Background: Ulcerative colitis (UC) is an autoimmune disease that is highly susceptible to recurrence, which is still a lack of effective drugs with minor side effects in clinic. Intervention of inflammatory differentiation of dendritic cells (DCs) might be an effective strategy to treat UC. Sishen Pills (SSP) is a classic Chinese herbal formula which has been demonstrated the protective effect of UC, but the mechanism remains unclear.

Purpose: To elucidate the protective effects of SSP against UC in mice and reveal its regulatory mechanism of DCs and the key active ingredients for the UC treatment based on transcriptomics, network pharmacology and experiments validation in vivo and vitro.

Method: The key active ingredients of SSP were detected and screened integrating LC-MS/MS and network pharmacology. A mouse UC model was induced with 3% sodium dextran sulfate and treated with SSP for 14 days to evaluate the efficacy. ELISA was used to detect the levels of IL-6, IL-1β and TNF-α in the colon; flow cytometry was used to detect the expression levels of DCs and their subpopulations; whole transcriptomic sequencing of differential RNAs in the colon and RT-PCR to detect key miRNAs to verify the sequencing results. Mouse bone marrow-derived dendritic cells (BMDCs) were isolated, an inflammatory model was constructed using 100 ng/ml LPS, and the effects of SSP on DC proliferation and apoptosis and their surface co-stimulatory molecule expression were examined; IL-6, IL-1β, TNF-α levels were measured by ELISA; RT-PCR and WB were performed to detect miR-505-3p, CDH1, E-cadherin expression. BMDCs with low expression of miR-505-3p were constructed by lentiviral transfection for further validation. The potential key ingredient was re-validated in vivo and vitro experiment.

Results: Animal experiments showed that SSP alleviated DSS-induced UC symptoms and colonic pathological injury in mice, and inhibited IL-6, IL-1β, TNF-α secretion and inflammatory DC proliferation and activation maturation. Network pharmacology predicted that evodiamine, isobavachalcone, curcumin, and engenol may play a key role in SSP. RNA sequencing revealed that miR-505-3p, as the differential miRNA, shared a large number of transcription factors with E-cadherin, and was involved in inflammatory differentiation regulation. In vivo experiments confirmed that SSP accelerated apoptosis, slowed down proliferation, inhibited inflammatory differentiation and IL-6, IL-1β, and TNF-α secretion in BMDCs, and decreased miR-505-3p, CDH1, and E-cadherin levels. After knocking down miR-505-3p, SSP could not regulate the inflammatory differentiation and IL-6, IL-1β, TNF-α level in BMDCs. Additionally, evodiamine was found and verified to be the key active ingredient of SSP in preventing the inflammatory differatiation of DCs.

Conclusion: SSP prevented the inflammatory differentiation of DCs by downregulating the expression of miR-505-3p, in which Evodiamine may played a key role.