FGF21 rejuvenates aged human adipose-derived mesenchymal stem cells via enhancement of TFE3-mediated autophagy flux

Intracerebral hemorrhage (ICH) is a neurological disorder characterized by a high mortality rate for which there is currently no definitive cure. Research has demonstrated that adipose-derived mesenchymal stem cells (ASCs) exhibit considerable potential in treating ICH. However, the advanced age of ICH patients and the necessary cell expansion before transplantation therapy could result in the senescence of ASCs, thereby compromising their viability and therapeutic efficacy. This study aims to investigate whether FGF21 (Fibroblast Growth Factor 21) can rejuvenate aged ASCs by enhancing macroautophagy/Autophagy flux and subsequently enhance the therapeutic efficacy of ICH. We demonstrated that the Autophagy flux of aged ASCs was significantly decreased and FGF21 treatment significantly reversed the senescence phenotype and increased the viability of aged ASCs. Mechanistically, our findings suggested that FGF21 rejuvenates aged ASCs by augmenting Autophagy flux, a process partly mediated by TFE3 (transcription factor E3) nuclear translocation. The FGF21-induced TFE3 nuclear translocation was partially facilitated potentially via the FGFR1-SIRT1-MTOR pathway. In addition, FGF21 enhanced the potential of senescent ASCs to differentiate into neurons. In the in vivo study, we further verified that FGF21 could enhance the therapeutic effect of ASCs on acute ICH rats. In conclusion, these results indicated that FGF21 could restore ASC viability by upregulating TFE3-mediated Autophagy flux in part through the FGFR1-SIRT1-MTOR signaling pathway, enhanced the potential to improve the differentiation of ASCs into neural stem cells and enhanced the therapeutic effect of ASCs transplantation in acute ICH.Abbreviations: FGF21: Fibroblast Growth Factor 21; TFE3: transcription factor E3; TFEB: transcription factor EB; DMEM: Dulbecco's modified Eagle medium; RAPA: rapamycin; 3-MA: 3-methyladenine; CQ: chloroquine; DMSO: dimethyl sulfoxide; RT-qPCR: quantitative real-time PCR; pAb: polyclonal antibody; mAb: monoclonal antibody; LAMP1: lysosomal associated membrane protein 1; SQSTM1/p62: sequestosome 1; MAP1lc3/LC3: microtubule associated protein 1 light chain 3; GFAP: glial fibrillary acidic protein; MAP2: microtubule associated protein 2; SOX2: SRY-box transcription factor 2; MOI: multiplicity of infection; FGFR1: Fibroblast Growth Factor receptor 1; SIRT1: Sirtuin 1; MTOR: mechanistic target of rapamycin kinase; ROS: reactive oxygen species; siRNA: small interfering RNA; OD: optical density; SASP: senescence-related secretion phenotype; IL6: interleukin 6; IL1B/IL-1β: interleukin 1 beta; TNF/TNF-α: tumor necrosis factor; CCL2/MCP-1: C-C motif chemokine ligand 2; BDNF: brain derived neurotrophic factor; VEGF: vascular endothelial growth factor; ICH: intracerebral hemorrhage; MLPT: modified limb placement test.