MSCs-exosomes can promote macrophage M2 polarization via exosomal miR-21-5p through Mesenteric injection: a promising way to attenuate murine colitis.

BACKGROUND AND AIMS: Exosome-based therapies are gaining increasing attention, with growing evidence suggesting a link between alterations in mesentery adipose tissue (MAT) and intestinal disease in Crohn's disease (CD). However, the specific mechanism by which mesenchymal stem cells (MSCs)-Exos may alleviate colitis through targeting MAT remains not fully understood. METHODS: Human umbilical cord MSCs (HucMSCs) were cultured to isolate the corresponding exosomes (HucMSCs-Exos), which were confirmed by their morphology, size distribution, and expression of markers. In vivo, 2,4,6-trinitrobenzenesulfonic acid solution (TNBS) and dextran sodium sulfate (DSS) -induced mouse colitis models were used to detect the therapeutic effects of HucMSCs-Exos. ELISA, qRT-PCR, western blotting, and immunofluorescence determined the expression of key molecules. Luciferase reporter assay was used to confirm the relationship between miR-21-5p and SPRY2. RESULTS: Exosomes treatment through mesenteric injection demonstrated therapeutic effects on mesenteric inflammation and colitis. These therapeutic benefits were contingent on macrophages, significantly facilitating the M2 polarization of mesenteric macrophages. The expression data from GSE159814 and GSE211008 revealed that exosomal miR-21-5p was enriched in HucMSCs-Exos and could be delivered to macrophages. Additionally, the results indicated that miR-21-5p could directly target the 3'UTR of SPRY2 and activate the phosphorylation of ERK to modify macrophage phenotypes. Mechanistically, exosomal miR-21-5p derived from HucMSCs could promote macrophage M2 polarization via the SPRY2/ERK axis. CONCLUSION: Mesenteric injection of HucMSCs-Exos significantly alleviates mesenteric inflammation and colitis by promoting mesenteric macrophage M2 polarization, making it a promising approach to treat colitis and suggesting therapeutic potential role of exosomal miR-21-5p in CD.

Circular RNA circCSPP1 promotes the occurrence and development of colon cancer by sponging miR-431 and regulating ROCK1 and ZEB1.

BACKGROUND: Colon cancer is a common malignant tumor of the digestive tract, and its incidence is ranked third among gastrointestinal tumors. The present study aims to investigate the role of a novel circular RNA (circCSPP1) in colon cancer and its underlying molecular mechanisms. METHODS: Bioinformatics analysis and reverse transcription-quantitative PCR were used to detect the expression levels of circCSPP1 in colon cancer tissues and cell lines. The effects of circCSPP1 on the behavior of colon cancer cells were investigated using CCK-8, transwell and clonogenic assays. Bioinformatics analysis along with luciferase, fluorescence in situ hybridization and RNA pull-down assays were used to reveal the interaction between circCSPP1, microRNA (miR)-431, Rho associated coiled-coil containing protein kinase 1 (ROCK1) and zinc finger E-box binding homeobox 1 (ZEB1). RESULTS: It was found that circCSPP1 expression was significantly upregulated in colon cancer tissues and cell lines. Overexpression of circCSPP1 significantly promoted the proliferation, migration and invasion of colon cancer cells, whereas silencing of circCSPP1 exerted opposite effects. Mechanistically, circCSPP1 was found to bind with miR-431. In addition, ROCK1 and ZEB1 were identified as the target genes of miR-431. Rescue experiments further confirmed the interaction between circCSPP1, miR-431, ROCK1 and ZEB1. Moreover, circCSPP1 promoted the expression level of ROCK1, cyclin D1, cyclin-dependent kinase 4, ZEB1 and Snail, and lowered the E-cadherin expression level. CONCLUSION: Taken together, the findings of the present study indicated that circCSPP1 may function as a competing endogenous RNA in the progression of colon cancer by regulating the miR-431/ROCK1 and miR-431/ZEB1 signaling axes.

IL-36ß promotes anti-tumor effects in CD8+ T cells by downregulating micro-RNA let-7c-5p.

BACKGROUND: The anti-tumor effect of interleukin (IL)-36ß-mediated activation of CD8+ T cells has been reported, but the molecular mechanism is largely undefined. METHODS: The levels of IL-36ß in pancreatic cancer were examined by quantitative real-time PCR (qRT-PCR) and immunohistochemical staining. Cytology and animal experiments were performed to study the effects of IL-36ß on the growth of pancreatic cancer cells. We then examined the changes of CD8+ T cells and natural killer (NK) cells in the tumor by flow cytometry. The microRNA expression profiles were determined by microarray analysis. RESULTS: The results revealed decreased levels of IL-36ß in pancreatic cancer tissues. In addition, IL-36ß inhibited tumor growth and promoted CD8+ T and NK cell proliferation in the tumor microenvironment (TME). Moreover, IL-36ß stimulated CD8+ T cells to synthesize high amounts of interferon-gamma (IFN-γ) and IL-2. Microarray analysis showed that IL-36ß administration to human and mouse CD8+ T cells consistently downregulated the miRNA, let-7c-5p. Downregulation of let-7c-5p resulted in IFN-γ and IL-2 upregulation in CD8+ T cells, whereas its upregulation had the opposite effect. Further experiments demonstrated that IL-36ß downregulated IFN-γ in let-7c-5p+ CD8+ T cells. CONCLUSIONS: These findings suggest IL-36ß promotes IFN-γ and IL-2 production in CD8+ T cells, as well as anti-tumor effects in CD8+ T cells by downregulating let-7c-5p.