Human menstrual blood-derived stem cells secreted ECM1 directly interacts with LRP1α to ameliorate hepatic fibrosis through FoxO1 and mTOR signaling pathway.

BACKGROUND: Human menstrual blood-derived stem cells (MenSCs), a major class of mesenchymal stem cells (MSCs), modulate intercellular signals via paracrine factors. Previous studies found that MenSC-derived secretomes exert protective effects against liver fibrosis. However, the underlying mechanisms of these observations remain unclear. METHODS: Extracellular Matrix Protein 1 (ECM1), identified in MenSCs culture medium using mass spectrometry, was employed to stably overexpress ECM1-HA or silence in MenSCs using lentiviral vectors. These genetically engineered cells were either intravenously injected into the carbon tetrachloride (CCl(4))-induced liver fibrosis mice or co-cultured with hepatic stellate cells (HSCs)-LX-2. The interaction between ECM1 and low-density lipoprotein receptor-related protein 1α (LRP1α) was confirmed using Co-Immunoprecipitation (Co-ip), Duolink Proximity Ligation Assays (PLA) and pull-down. LRP1 deficient mice were generated via intravenous administration of adeno-associated-virus-8. The downstream molecular mechanisms were characterized by non-target metabolomics and multiplex immunohistochemical staining. RNA sequencing was performed to evaluate the genetic alterations in various genes within the MenSCs. RESULTS: MenSC-secreted ECM1 exhibits potential to ameliorate liver fibrosis by inactivating HSCs, improving liver functions, and reducing collagen deposition in both cellular and mouse model of the CCl(4)-induced liver fibrosis. Mechanistically, a novel interaction was identified that ECM1 directly bound to cell surface receptor LRP1α. Notably, the antifibrotic efficacy of MenSC was negated in LRP1-deficient cells and mice. Moreover, the ECM1-LRP1 axis contributed to the alleviation of liver fibrosis by suppressing AKT/mTOR while activating the FoxO1 signaling pathway, thereby facilitating pyrimidine and purine metabolism. Additionally, ECM1-modified MenSCs regulate the transcription of intrinsic cytokine genes, further mitigating liver fibrosis. CONCLUSIONS: These findings highlight an extensive network of ECM1-LRP1 interaction, which serve as a link for providing promising insights into the mechanism of MenSC-based drug development for liver fibrosis. Our study also potentially presents novel avenues for clinical antifibrotic therapy.