Apoptotic extracellular vesicles from peripancreatic adipose-derived mesenchymal stem cells ameliorate severe acute pancreatitis through the transcription factor EB-mediated autophagy-lysosomal pathway: an experimental study

BACKGROUND: Mesenchymal stem cells (MSCs) and their extracellular vesicles (EVs) have remarkable potential in alleviating the severity of pancreatic inflammation. However, most transplanted MSCs undergo apoptosis shortly after in vivo administration, producing apoptotic EVs (ApoEVs). Our study investigated the potential role and molecular mechanisms of ApoEVs derived from apoptotic MSCs in ameliorating severe acute pancreatitis (SAP). METHODS: DiO-labeled peripancreatic adipose-derived stem cells (P-ADSCs) were administered to rats with SAP to monitor P-ADSC apoptosis. ApoEVs were isolated from P-ADSCs subjected to apoptosis induction, and conventional EVs were obtained from untreated P-ADSCs. The morphology, size distribution and marker protein expression of ApoEVs and EVs were characterized, and functional differences were assessed via transcriptomic and proteomic analyses to compare their gene and protein compositions. The rat pancreatic acinar cell (PAC) line AR42J was used to assess cellular responses to ApoEVs, and an SAP rat model was used to compare the therapeutic efficacy of ApoEVs in ameliorating SAP. Specific inhibitors and small interfering RNA were used to perform loss-of-function assays. RESULTS: P-ADSCs underwent apoptosis in the pancreas within 72 h after being injected into rats with SAP. Notably, ApoEVs exhibited superior therapeutic effects in ameliorating SAP than conventional EVs. Transcriptomic and proteomic analyses revealed that ApoEVs carry numerous autophagy-lysosome-related genes and proteins, enabling them to efficiently traverse the circulatory system and reach the pancreatic tissues. Following internalization by pancreatic acinar cells, ApoEVs effectively restored the impaired autophagic function of damaged acinar cells. In rats with SAP, ApoEVs treatment effectively alleviated both systemic and local tissue inflammation associated with SAP. Mechanistically, ApoEVs attenuated SAP by enhancing the transcription factor EB (TFEB)-mediated autophagy-lysosomal pathway. CONCLUSION: Given the high yield and ease of obtaining ApoEVs from P-ADSCs, our findings underscore the significant therapeutic potential of ApoEVs from dying P-ADSCs in treating SAP, highlighting their broad relevance for cell-free therapeutic approaches.