title: Clustering siRNA conjugates for MMP-responsive therapeutics in chronic wounds of diabetic animals.
abstract: The MMP-responsive breakdown of siRNA clusters was translated to site-specific gene transfection and enhanced wound healing in diabetic ulcers. MMP-2 siRNA was chemically tethered to the end of multi-armed PEG via MMP-cleavable linkers (4PEG-siRNA) and subsequently clustered into submicron particles complexed with LPEI. 4PEG-siRNA was more tightly complexed with LPEI and the associated cluster showed higher resistance against RNase attack, in comparison to naked siRNA. Because the size of the clusters increased depending on the increase in charge ratio of LPEI to siRNA, cellular uptake of the 4PEG-siRNA/LPEI cluster was significantly attenuated due to the huge size of the cluster. However, upon MMP treatment, the cluster dissociated into smaller particles and was efficiently endocytosed by cells. An in vivo fluorescence resonance energy transfer (FRET) study also revealed that the clusters were effectively dissociated in MMP-rich environments of dorsal wounds in diabetic animals. In addition, diabetic ulcers treated with the clusters showed a faster wound closure rate and the recovered tissue expressed a larger amount of cytokeratin along with a lower expression level of MMP-2 compared to the other groups.
authors.affiliation: Department of Medical Biomaterials Engineering, Kangwon National University, Chuncheon,24341, Republic of Korea. hsyoo@kangwon.ac.kr.
authors.forename: Hye Sung
authors.initials: HS
authors.lastname: Kim
authors.forename: Young Ju
authors.initials: YJ
authors.lastname: Son
authors.forename: Hyuk Sang
authors.initials: HS
authors.lastname: Yoo
mesh_terms: D000818:Animals; D003920:Diabetes Mellitus / Q000628:therapy*; D005260:Female; D020868:Gene Silencing; D020778:Matrix Metalloproteinase 2 / Q000235:genetics*; D051379:Mice; D008810:Mice, Inbred C57BL; D041681:NIH 3T3 Cells; D034741:RNA, Small Interfering / Q000627:therapeutic use*; D012883:Skin Ulcer / Q000628:therapy*; D014945:Wound Healing
chemical_list: D034741:RNA, Small Interfering; D020778:Matrix Metalloproteinase 2