Collagen/GAG scaffolds activated by RALA-siMMP-9 complexes with potential for improved diabetic foot ulcer healing

Le Ping Yan, Irene Mencía Castaño, Rukmani Sridharan, Domhnall Kelly, Mark Lemoine, Brenton L. Cavanagh, Nicholas J. Dunne, Helen O. McCarthy, Fergal J. O'Brien*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

3 Citations (Scopus)

Abstract

Impaired wound healing of diabetic foot ulcers has been linked to high MMP-9 levels at the wound site. Strategies aimed at the simultaneous downregulation of the MMP-9 level in situ and the regeneration of impaired tissue are critical for improved diabetic foot ulcer (DFU) healing. To fulfil this aim, collagen/GAG (Col/GAG) scaffolds activated by MMP-9-targeting siRNA (siMMP-9) were developed in this study. The siMMP-9 complexes were successfully formed by mixing the RALA cell penetrating peptide with siMMP-9. The complexes formulated at N:P ratios of 6 to 15 had a diameter around 100 nm and a positive zeta potential about 40 mV, making them ideal for cellular uptake. In 2 dimensional (2D) culture of human fibroblasts, the cellular uptake of the complexes surpassed 60% and corresponded to a 60% reduction in MMP-9 gene expression in low glucose culture. In high glucose culture, which induces over-expression of MMP-9 and therefore serves as an in vitro model mimicking conditions in DFU, the MMP-9 gene could be downregulated by around 90%. In the 3D culture of fibroblasts, the siMMP-9 activated Col/GAG scaffolds displayed excellent cytocompatibility and ~60% and 40% MMP-9 gene downregulation in low and high glucose culture, respectively. When the siMMP-9 complexes were applied to THP-1 macrophages, the primary cell type producing MMP-9 in DFU, MMP-9 gene expression was significantly reduced by 70% and 50% for M0 and M1 subsets, in 2D culture. In the scaffolds, the MMP-9 gene and protein level of M1 macrophages decreased by around 50% and 30% respectively. Taken together, this study demonstrates that the RALA-siMMP-9 activated Col/GAG scaffolds possess high potential as a promising regenerative platform for improved DFU healing.

Original languageEnglish
Article number111022
JournalMaterials Science and Engineering C
Volume114
Early online date30 Apr 2020
DOIs
Publication statusPublished - Sep 2020

Bibliographical note

Funding Information:
This study was funded by Science Foundation Ireland (SFI) through the Advanced Materials and Bioengineering Research (AMBER) Centre ( SFI/12/RC/2278 ), and European Union 's Horizon 2020 Research and Innovation Programme through GENE2SKIN project (Grant Agreement Number 692221 ). The authors thank Dr. Tomas Gonzalez-Fernandez for the assistance in this study, and Dr. Rosanne M. Raftery and Ms. Sarah M. Casey for the revision of this manuscript.

Funding Information:
This study was funded by Science Foundation Ireland (SFI) through the Advanced Materials and Bioengineering Research (AMBER) Centre (SFI/12/RC/2278), and European Union's Horizon 2020 Research and Innovation Programme through GENE2SKIN project (Grant Agreement Number 692221). The authors thank Dr. Tomas Gonzalez-Fernandez for the assistance in this study, and Dr. Rosanne M. Raftery and Ms. Sarah M. Casey for the revision of this manuscript.

Publisher Copyright:
© 2020 Elsevier B.V.

Copyright:
Copyright 2020 Elsevier B.V., All rights reserved.

Keywords

  • Cell penetrating peptide
  • Diabetic foot ulcer
  • Gene-activated scaffold
  • MMP-9
  • siRNA delivery

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

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