Inhibition Of MiR-199a-5p Rejuvenates Aged Mesenchymal Stem Cells And Enhances The Therapeutic Effect Of Idiopathic Pulmonary Fibrosis

ObjectiveIdiopathic pulmonary fibrosis(IPF),characterized by interstitial fibrosis with decreasing lung volumes,is a progressive scarring lung disease of unknown etiology with no curable treatment and is leading to pulmonary dysfunction eventually resulting in death.Mesenchymal stem cell(MSC)-based therapy has emerged as a novel strategy for IPF treatment.In this study,we investigated the potential mechanisms underlying miR-199a-5p regulates IPF-MSCs senescence and whether its inhibition could rejuvenate IPF-MSCs and enhance their therapeutic efficacy against IPF.MethodsIn this study,IPF-MSCs and control-MSCs were isolated from the adipose tissue of IPF patients and age-matched healthy donors,respectively.Cumulative population multiplication curves,Western blotting and SA-β-gal staining were used to evaluate the senescence of MSCs between the two groups.Cell proliferation was detected by Ki67 immunofluorescence staining,and DNA damage was detected by y-H2AX immunofluorescence staining.The level of miR-199a-5p was detected by RT-PCR,and the number of autophagosome was determined by transmission electron microscope(TEM)in the two MSCs groups.The therapeutic efficacy of anti-miR-199a-5p-IPF-MSCs was assessed using a mouse model of bleomycin-induced lung fibrosis.ResultsThe surface markers of control-MSCs and IPF-MSCs were similar.IPF-MSCs showed an increased cellular senescence and decreased proliferation compared with control-MSCs.The expression of miR-199a-5p was significantly enhanced in the serum of IPF patients and IPF-MSCs compared with healthy donors and control-MSCs.Upregulation of miR-199a-5p induced senescence in control-MSCs,whereas downregulation resulted in rejuvenation of IPF-MSCs.Mechanistically,miR-199a-5p inhibited autophagy of MSCs through Sirtl/AMPK signaling pathway,leading to cellular senescence.Thus,inhibition of miR-199a-5p promoted autophagy and improved senescence in IPF-MSCs by activating the Sirtl/AMPK signaling pathway.Transplantation of anti-miR-199a-5p-IPF-MSCs ameliorated the symptoms of pulmonary fibrosis and improved the ability to against lung fibrosis progression compared with IPF-MSCs in experimental pulmonary fibrosis mice.ConclusionOur study showed that miR-199a-5p inhibits autophagy and induces senescence in IPF-MSCs by regulating the Sirt1/AMPK signaling pathway,and down-regulation of miR-199a-5p rejuvenates IPF-MSCs and improves the efficacy of MSCs in the treatment of pulmonary fibrosis.Thus,miR-199a-5p is a novel target to rejuvenate IPF-MSCs and enhance their beneficial effects.