Self-Assembled Wound Dressings Silence MMP-9 and Improve Diabetic Wound Healing In Vivo
Self-Assembled Wound Dressings Silence MMP-9 and Improve Diabetic Wound Healing In Vivo
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DOI：
10.1002/adma.201503565
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发表时间：
2016-03-02
影响因子：
29.4
通讯作者：
Hammond, Paula T.
中科院分区：
文献类型：
--
作者：
Castleberry, Steven A.;Almquist, Benjamin D.;Hammond, Paula T.
DOI：10.1002/adma。 201503565 肉芽组织，填充伤口的早期结缔组织，并使对伤口愈合过程至关重要的重要生长因子失活。 [13] MMP 过度表达的这些和其他并发症激发了对开发 MMP 抑制剂的大量研究；然而，特异性低、生物利用度差和严重的肌肉骨骼副作用阻碍了这些努力。 [14]为了解决这些问题，我们假设局部使用 RNA 干扰 (RNAi) 来减少伤口中 MMP-9 的表达将是增加伤口床内 ECM 积累和改善伤口愈合的有效方法。使用小干扰 RNA (siRNA) 技术的 RNAi 是一种很有前途的方法，用于序列特异性靶向 mRNA 进行破坏，从而能够敲低几乎任何表达的蛋白质。 [15]虽然 RNAi 在医学上的潜在应用有很多，但由于 siRNA 的快速酶促降解以及通过肝肾系统的清除，siRNA 的体内递送仍然是一个主要障碍。 [16]局部递送规避了递送的许多挑战，但仍必须保护 siRNA 免遭酶促降解并有效进入感兴趣组织内的靶细胞。仅开发了少数用于局部 siRNA 递送的系统；那些依赖于必须直接注射到组织中的大体积水凝胶制剂的方法[17]，或者必须多次应用才能达到功效的重新利用的纳米颗粒溶液[18]，这两种方法都没有被证明可以治疗组织内已知的医学病症（即病理性失调）。此外，这一新领域仍需应对独特的挑战，包括将 siRNA 递送和释放与现有医疗技术和平台轻松结合的能力。逐层 (LbL) 技术已在无数生物医学应用中得到证实，可从多种材料表面进行传输，包括不锈钢和可降解聚合物基质。 [19]我们之前已经证明，LbL 的掺入和 siRNA 的递送可以在体外实现报告基因的显着且持续的敲低，[20]，尽管将这些结果转化为更复杂的体内环境的能力仍然未知。因此，开发这项技术，利用有意义的治疗基因靶标，将 siRNA 有效递送至体内局部区域，为治疗特定部位疾病（包括 DFU 以及心血管疾病、癌症和移植排斥）带来了重大进展。在这里，我们报告了使用 LbL 在高度蛋白水解的伤口床内实现目标基因的显着敲低，效果持续至少 2 周。使用商业化的伤口愈合受损是糖尿病患者护理中的一个关键问题。美国每年新增超过 75 万例糖尿病足溃疡 (DFU) 病例，导致超过 7 万例下肢截肢。[1]在健康患者中，伤口愈合是一个高度精心策划的重叠阶段的过程：止血、炎症、组织形成和组织重塑。 [2]在溃疡性伤口愈合中，这一过程被中断，伤口持续处于发炎状态数周至数月，并且在许多情况下永远不会消退。糖尿病溃疡的病理学是由这种慢性炎症引起的，部分原因是伤口床中细胞外基质 (ECM) 蛋白酶的过度表达。[3-5] 因此，DFU 内 ECM 的积累显着减少，阻碍伤口上皮闭合，并显着……
DOI: 10.1002/adma. 201503565 granulation tissue, the early connective tissue that fills a wound, as well as inactivates important growth factors that are critical to the process of wound healing.[13] These and other complications of MMP overexpression have spurred substantial research into developing MMP inhibitors; however, efforts have been hampered by low specificity, poor bioavailability, and serious musculoskeletal side effects.[14] In order to address these issues, we hypothesized that using RNA interference (RNAi) locally to reduce MMP-9 expression in the wound would be an effective approach for increasing ECM accumulation within the wound bed and improving wound healing. RNAi using small interfering RNA (siRNA) technology is a promising approach for the sequence-specific targeting of mRNAs for destruction, enabling the knockdown of virtually any expressed protein.[15] While the potential applications of RNAi in medicine are numerous, in vivo delivery of siRNA remains a major obstacle due to rapid enzymatic degradation of siRNAs and clearance via the hepatic and renal systems.[16] Local delivery circumvents many of the challenges of delivery, but siRNA must still be protected from enzymatic degradation and effectively enter target cells within the tissues of interest. Only a few systems have been developed for local siRNA delivery; those that have rely on bulky hydrogel formulations that must be injected directly into tissues [17] or re-purposed nanoparticle solutions that must be applied multiple times to achieve efficacy [18] Neither of these approaches has been demonstrated to treat a known medical condition (ie, pathologic dysregulation) within tissues. Furthermore, there are unique challenges that are still to be met in this new area, including the ability to easily combine siRNA delivery and release with existing medical technologies and platforms. Layer-by-Layer (LbL) technology has been demonstrated in a myriad of biomedical applications for delivery from a broad range of material surfaces, including stainless steel and degradable polymer matrices.[19] We have previously demonstrated that LbL incorporation and delivery of siRNA can achieve significant and sustained knockdown of reporter genes in vitro,[20] although the ability to translate these results to a more complex environment in vivo remained unknown. Therefore, developing this technology to effectively deliver siRNA to a localized area in vivo using a meaningful therapeutic gene target presents a significant advancement for the treatment of site-specific disorders, including DFUs as well as cardiovascular diseases, cancers, and transplant rejection. Here, we report the use of LbL to achieve significant knockdown of a target gene within a highly proteolytic wound bed, with the effects sustained for at least 2 weeks. Using a commerciallyImpaired wound healing is a critical concern in the care of diabetic patients. Every year there are more than 750 000 new cases of diabetic foot ulcers (DFUs) in the United States, leading to over 70 000 lower limb amputations.[1] In healthy patients, wound healing is a highly orchestrated process of overlapping phases: hemostasis, inflammation, tissue formation, and tissue remodeling.[2] In ulcerative wound healing this process is interrupted and the wound persists in an inflamed state for weeks to months and in many cases never resolves. The pathology of the diabetic ulcer results from this chronic inflammation, due in part to the overexpression of extracellular matrix (ECM) proteases in the wound bed.[3–5] As a result, ECM accumulation within the DFU is dramatically reduced, impeding epithelial closure of the wound and significantly …