Background Adipose-derived stem cells (ADSCs) have provided promising applications for Crohn’s disease (CD). However, the practical efficacy of ADSCs remains controversial, and their mechanism is still unclear. Based on the pathogenesis of dysregulated immune responses and abnormal lymphatic alterations in CD, vascular endothelial growth factor-C (VEGF-C) is thought to be a favourable growth factor to optimize ADSCs. We aimed to investigate the efficacy of VEGF-C-stimulated ADSCs and their dual mechanisms in both inhibiting inflammation “IN” and promoting inflammation “OUT” in the intestine. Methods Human stem cells isolated from adipose tissues were identified, pretreated with or without 100 ng/ml VEGF-C and analysed for the secretion of cell culture supernatants in vitro. Lymphatic endothelial cells (LECs) were treated with ADSCs-conditioned medium or co-cultured with ADSCs and VEGF-C stimulated ADSCs. Changes in LECs transmigration, and VEGF-C/VEGFR-3 mRNA levels were assessed by transwell chamber assay and qRT–PCR. ADSCs and VEGF-C-stimulated ADSCs were intraperitoneally injected into mice with TNBS-induced chronic colitis. ADSCs homing and lymphatic vessel density (LVD) were evaluated by immunofluorescence staining. Lymphatic drainage was assessed using Evans blue. Cytokines and growth factors expression was detected respectively by ELISA and qRT–PCR. The protein levels of VEGF-C/VEGFR-3-mediated downstream signals and the NF-κB pathway were assayed by western blot. Faecal microbiota was measured by 16S rRNA sequencing. Results ADSCs stimulated with VEGF-C released higher levels of growth factors (VEGF-C, TGF-β1, and FGF-2) and lower expression of cytokines (IFN-γ and IL-6) in cell supernatants than ADSCs in vitro (all P < 0.05). Secretome released by VEGF-C stimulated ADSCs exhibited a stronger LEC migratory capability and led to elevated VEGF-C/VEGFR-3 expression, but these effects were markedly attenuated by VEGFR-3 inhibitor. VEGF-C-stimulated ADSCs homing to the inflamed colon and mesenteric lymph nodes (MLNs) can exert stronger efficacy in improving colitis symptoms, reducing inflammatory cell infiltration, and significantly enhancing lymphatic drainage. The mRNA levels and protein concentrations of anti-inflammatory cytokines and growth factors were markedly increased with decreased proinflammatory cytokines in the mice treated with VEGF-C-stimulated ADSCs. Systemic administration of VEGF-C-stimulated ADSCs upregulated the colonic VEGF-C/VEGFR-3 pathway and activated downstream AKT and ERK phosphorylation signalling, accompanied by decreased NF-κB p65 expression. A higher abundance of faecal p-Bacteroidetes and lower p-Firmicutes were detected in mice treated with VEGF-C-stimulated ADSCs (all P < 0.05). Conclusion VEGF-C-stimulated ADSCs improve chronic intestinal inflammation by promoting lymphatic drainage and enhancing paracrine signalling via activation of VEGF-C/VEGFR-3-mediated signalling and inhibition of the NF-κB pathway. Our study may provide a new insight into optimizing ADSCs treatment and investigating potential mechanisms in CD.
Background Creeping fat (CrF) has been recognized to play a positive role in Crohn’s disease (CD) progression, yet the cellular compositions within mesenteric adipose tissue (MAT) and their potential mechanism in CrF formation are poorly understood. Methods Analysis of 10X single-cell RNA sequencing was performed on 67 064 cells from 3 pairs of surgically resected samples of CrF and their uninvolved MAT. The results were validated in another cohort with 6 paired MAT samples by immunofluorescence. Results All samples manifested excellent consistency and repeatability in our study, and 10 cell types from the transcriptome atlas, including 20 clusters, were identified. In CrF, a specific vascular endothelial cell subpopulation highly expressing lipoprotein lipase was first identified, with a significantly increased proportion. This vascular endothelial cell subpopulation manifested robust peroxisome proliferator-activated receptor γ (PPARγ) transcription activity and an upregulated PPAR signaling pathway and was involved in lipid metabolism and the antibacterial response. A novel fibroblast subpopulation (FC3) with remarkable GREM1 and RFLNB expression was identified and validated to predominantly accumulate in the CrF. The FC3 was annotated as inflammation-associated fibroblasts, which are characterized by inflammatory responses and the regulation of Smad phosphorylation related to intestinal fibrosis. The trajectory of fibroblasts revealed their pro-inflammatory and profibrotic conversion tendency during CrF formation with corresponding gene dynamics. Additionally, we unprecedently dissected the different origins and functions of 6 macrophage subclusters within the myeloid compartment. Conclusions Our results uncover the cellular heterogeneity in the MAT of CD and the role of these various cellular compositions in CrF development. This comprehensive understanding of CrF provides future directions for in-depth research on and potential targets for MAT-based treatment.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.