MiR146a-loaded engineered exosomes released from silk fibroin patch promote diabetic wound healing by targeting IRAK1

Unhealable diabetic wounds need to be addressed with the help of newer,more efficacious strategies.Exosomes combined with biomaterials for sustained delivery of therapeutic agents are expected to bring new hope for chronic wound treatment.Here,the engineered exosomes modified for efficiently loading miR146a and attaching to silk fibroin patch(SFP)were demonstrated to promote diabetic wound healing.Silk fibroin binding peptide(SFBP)was screened through phage display,and SFBP-Gluc-MS2(SGM)and pac-miR146a-pac fusion protein were constructed.The designed exosomes(SGM-Exos,miR146a-Exos,and SGM-miR146a-Exos)were isolated from the engineered placental mesenchymal stem cells(PMSCs)transduced with SGM or/and pac-miR146a-pac protein.Gluc signals indicated SGM-Exo@SFP markedly increased the binding rate and the stability of SGM-Exo.Moreover,the loading efficiency of miR146a in SGM-miR146a-Exos was ten-fold higher than that in miR146a-Exos.Superior to untreated,SGM-miR146a-Exo-only treated,and SFP-only treated groups,SGM-miR146a-Exo@SFP drived wound healing associated with less inflammation,collagen deposition,and neovascularization.The transcriptomics analysis suggested anti-inflammatory and regenerative effects with SGM-miR146a-Exo@SFP treatment.Here,we show efficient exosome@biomaterial-based miRNA delivery systems for regenerative medicine and tissue engineering.

Calcium silicate accelerates cutaneous wound healing with enhanced re-epithelialization through EGF/EGFR/ERK-mediated promotion of epidermal stem cell functions

Background:Human epidermal stem cells(hESCs)play an important role in re-epithelialization and thereby in facilitating wound healing,while an effective way to activate hESCs remains to be explored.Calcium silicate(CS)is a form of bioceramic that can alter cell behavior and promote tissue regeneration.Here,we have observed the effect of CS on hESCs and investigated its possible mechanism.Methods:Using a mouse full-thickness skin excision model,we explored the therapeutic effect of CS on wound healing and re-epithelialization.In vitro,hESCs were cultured with diluted CS ion extracts(CSIEs),and the proliferation,migration ability and stemness of hESCs were evaluated.The effects of CS on the epidermal growth factor(EGF),epidermal growth factor receptor(EGFR)and extracellular signal-related kinase(ERK)signaling pathway were also explored.Results:In vivo,CS accelerated wound healing and re-epithelialization.Immunohistochemistry demonstrated that CS upregulated cytokeratin 19 and integrinβ1 expression,indicating that CS improved hESCs stemness.In vitro studies confirmed that CS improved the biological function of hESCs.And the possible mechanism could be due to the activation of the EGF/EGFR/ERK signaling pathway.Conclusion:CS can promote re-epithelialization and improve the biological functions of hESCs via activating the EGF/EGFR/ERK signaling pathway.