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

Abstract

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.

Extracellular Vesicles for Therapeutic Nucleic Acid Delivery: Loading Strategies and Challenges

“…Its C1C2 domains have also been extensively used for EV engineering. Recently, a capsid protein of phage MS2 was fused to C1C2 to load pre-miRNA-146a into EVs [ 261 ]. The MS2 capsid protein has interacted with binding sites, the RNA stem-loop structures, flanking the sequence of pre-miRNA-146a, providing its encapsulation and enrichment in EVs.…”

Small extracellular vesicles: Yields, functionalization and applications in diabetic wound management

“…The phage MS2‐coated protein specifically binds to pac‐modified RNA. Therefore, the loading efficiency of pac‐pre‐miR146a in sEVs were increased by approximately 10‐fold compared with conventional methods 28 …”

“…In addition to small molecule drugs, a variety of miRNA cargoes inside sEVs are involved in the expression regulation of inflammatory factors 123 . Recently, we successfully engineered sEVs by constructing fusion proteins SFBP‐Gluc‐MS2 (SGM) and pac‐miR146a‐pac, in which the exosomal membrane protein Lactadherin was fused to RNA binding protein and SFBP 28 . This engineering strategy significantly improved the therapeutic efficacy of sEVs.…”

“…Therefore, the loading efficiency of pac-pre-miR146a in sEVs were increased by approximately 10-fold compared with conventional methods. 28 4.1.2 | Co-culturing with cargoes Culturing parent cells with drugs is usually employed to encapsule small hydrophobic drugs in the lumen of sEVs. These drugs were usually packaged in Golgi-derived vesicles in parent cells through endocytosis and were loaded in sEVs in a nonspecific and uncontrolled manner.…”

“…23,24 However, inefficient therapeutic cargoes, low yields, and high production costs limit the clinical translation of natural sEVs. Researchers have attempted to improve the yields [25][26][27] and functionalize sEVs 28,29 to remove these barricades and promote clinical translation. 30 Herein, we overview the biogenesis and uptake of sEVs, the methods to increase the yields of sEVs and obtain functionalized sEVs as well as specific applications of engineered sEVs in diabetic wound management.…”