Mechanism Study Of Exosome-encapsulated MiR-187-3p On Resistance To Propranolol In Hemangioma-derived Stem Cells

Objectives: Infantile hemangioma(IH),which is the most common tumor of infancy,is a benign vascular tumor deriving from the abnormal proliferation of endothelial cells.Since2008,oral propranolol has gradually become the therapy of choice for the treatment of IH.However,a small number of patients with IH have resistance to propranolol.Propranololresistant IH is defined as the absence of the expected therapeutic response to oral propranolol,that is,continued IH growth during the proliferating stage or no IH involution during the post-proliferative stage,after at least 4 weeks of oral propranolol at 2 mg/kg/d.To date,the cause of resistance to propranolol is not yet known.In higher eukaryotes,mi RNA is a key factor in the regulation of gene post-transcriptional expression.Mi RNA often has multiple target genes.Targeted,cell-specific exosomal delivery can minimize the side effects of mi RNA and increase its concentration within a single recipient cell.mir-187-3p is a novel,cancer-related mi RNA which has been previously confirmed to promote or inhibit various malignancies.However,the role of mir-187-3p in the development and progression of IH remains unclear.In this study,human adipose mesenchymal stem cells(h AMSCs)exosomes were selected as the carrier of mir-187-3p.By changing the level of mir-187-3p in hemangioma-derived stem cells(Hem SCs),the molecular mechanism and signaling pathway of the effect of mir-187-3p on Hem SCs and the effect of mir-187-3p changes on propranolol resistance of Hem SCs were explored.Materials and methods: This study includes two parts: basic and clinical research.In the basic research,IH tissues were collected and the expression of mi R-187-3p was analyzed by q RT-PCR to find the correlation between mi R-187-3p and propranolol resistance of IH.Meanwhile,stably transfected h AMSCs were constructed in vitro,h AMSCs exosomes loading mi R-187-3p were extracted,and the exosomes were characterized by transmission electron microscopy and western blotting.Hem SCs were then isolated,identified,and cultured.Characterization of Hem SCs was performed through differentiation assays and tube formation assay,and the effect of mi R-187-3p changes on resistance to propranolol in Hem SCs was investigated.In the clinical research,276 patients with proliferative IH were included,and the efficacy and safety of oral propranolol and atenolol in the treatment of IH were compared and analyzed.Results: The expression level of mi R-187-3p in Hem SCs was much higher than that in normal skin fibroblasts.Further analysis revealed that mi R-187-3p expression levels in Hem SCs with resistance to propranolol were significantly lower than levels of those who were sensitive to propranolol.The expression level of mi R-187-3p in the blood serum of patients with proliferative IH is much lower than that of normal controls.The expression level of mi R-187-3p in blood serum of propranolol-resistant patients is much lower than that of propranolol-sensitive patients.After co-culturing the h AMSCs exosomes loading Cy3-pre-mi R-187-3p with Hem SCs for a period,green PKH67 signal in Hem SCs cytoplasm,red mi R-187-3p signal,and the colocalization signal of Cy3-mi R-187-3p and PKH67 in Hem SCs can been detected under laser confocal microscope.Exosome-encapsulated mi R-187-3p inhibits propranolol resistance in Hem SCs.NIPBL is a direct target of mi R-187-3p in Hem SC.NIPBL down-regulates propranolol resistance in Hem SCs.Reintroduction of NIPBL abolished the effects of mi R-187-3p on Hem SCs propranolol resistance.Retrospective study has found that oral propranolol or atenolol have similar efficacy and tolerability in the treatment of IH(P> 0.05),without serious adverse drug reactions.Compared to propranolol,oral atenolol may have less potential adverse effects to brain.Conclusions: This study confirms that the expression of mi R-187-3p is inversely related to the resistance of propranolol to IH.Exosome-encapsulated mi R-187-3p can be delivered among Hem SCs;the expression of NIPBL is down-regulated in IH.mi R-187-3p enhances Hem SCs sensitivity to propranolol by targeting NIPBL,which indicates that mi R-187-3p can be used as a new prognostic factor and potential target for the treatment of IH.Retrospective study confirms that,compared with propranolol,atenolol has the advantage of being administered at a lower dose and potentially fewer potential adverse effects to brain.Therefore,atenolol is expected to become one of the first choices for the treatment of IH.