Nanofiber-based Delivery of Combined Immune-modulating Compounds to Minimize Infection and Enhance Wound Healing

ABSRTA 尽管尽了很大努力保持手术室的无菌，但手术部位感染(SSI)仍然是一个严重和残存的问题。 天生的问题，在美国每年导致多达8200名患者死亡。我们的长期目标是开发新的疗法， 有效地将SSI的风险降至最低，促进伤口愈合。在本奖项的前几个供资周期中， 我们已经证明：1)维生素D和其他免疫球蛋白的成功包裹和持续释放。 调节化合物诱导更高水平的中草药抗菌肽(CAMP)基因和蛋白(hCAP18/L1- 37)免疫细胞和角质形成细胞在细胞培养、人cAMP转基因小鼠创伤模型和 人体皮肤移植；ii)局部应用维生素D增加皮肤伤口感染时对金黄色葡萄球菌的杀灭作用 使用我们的人cAMP转基因小鼠的模型；以及iii)从免疫细胞分泌的外体 维生素D含有较高水平的hCAP18/LL-37。此外，我们还开发了一种新型的气体发泡膨胀剂 制造改进的3D纳米纤维支架的技术，该支架洗脱促进免疫细胞渗透的维生素D， 诱导hCAP18/LL-37，减轻炎症反应，促进新生血管形成和胶原沉积 植入人类免疫系统的小鼠。基于这些发现和我们的初步数据，我们的目标是 提案的重点是开发以纳米纤维为基础的敷料，以增强天然免疫力。我们结束了- ARCHING假说是将免疫调节化合物与外切体共包裹在一起 3D纳米纤维支架中经过处理的免疫细胞将协同增强对SSI的保护并促进 伤口愈合比单独使用任何一个组件都要好。要做到这一点，有三个具体的目标：1)恶魔- 高效包埋和洗脱改良3D纳米纤维中的免疫调节化合物 支架；2)测定来自预涂或人类来源的外切体的抗菌和伤口愈合效果 CAMP转染的免疫细胞；3)证明免疫调节化合物和外源基因的有效性。 SOMES-共包含3D纳米纤维支架，以促进愈合和防止感染在我们的人源化反式 基因小鼠模型和体外人皮肤移植。在我们之前拨款的基础上，我们预计会取得成功 这一更新目标的完成将为下一代小说的发展奠定坚实的基础 治疗性抗感染创面敷料，可以大大加快愈合速度，降低SSI的发生率，并将 抗生素耐药性的发展。我们还希望这些敷料可以有效地治疗 创伤和与战斗有关的伤害。

ABSRTACT Despite major efforts to keep operating rooms sterile, surgical site infections (SSIs) remain a serious and stub- born problem, killing up to 8,200 patients a year in the U.S. Our long-term goal is to develop novel therapies that effectively minimize risk of SSIs and promote wound healing. During the previous funding cycles of this award, we have demonstrated that i) successful encapsulation and sustained release of vitamin D and other immuno- modulating compounds induced higher cathelicidin antimicrobial peptide (CAMP) gene and protein (hCAP18/LL- 37) levels in immune cells and keratinocytes in cell culture, a human CAMP transgenic mouse wound model and human skin explants; ii) topical vitamin D increased killing of Staphylococcus aureus in a skin wound-infection model using our human CAMP transgenic mouse; and iii) exosomes secreted from immune cells treated with vitamin D contained higher levels of hCAP18/LL-37. Furthermore, we developed a novel gas-foaming expansion technique to fabricate improved 3D nanofiber scaffolds eluting vitamin D that promoted immune cell infiltration, induced hCAP18/LL-37, decreased inflammation, and promoted neovascularization and collagen deposition in human immune system-engrafted mice. Building on these findings, and our preliminary data, the goal of our proposal focuses on the development of nanofiber-based dressings for enhancing innate immunity. Our over- arching hypothesis is that co-encapsulating immunomodulating compounds with exosomes secreted from treated immune cells in 3D nanofiber scaffolds will synergistically enhance protection against SSIs and promote wound healing better than either component alone. To accomplish this, there are three specific aims: 1) Demon- strate efficient encapsulation and elution of immunomodulating compounds from our improved 3D nanofiber scaffolds; 2) Determine the antimicrobial and wound-healing efficacy of exosomes derived from primed or human CAMP transfected immune cells; and 3) Demonstrate the efficacy of immunomodulating compounds and exo- somes - co-incorporated 3D nanofiber scaffolds to promote healing and prevent infection in our humanized trans- genic mouse model and ex vivo human skin explants. Building on work from our prior grant, we expect successful completion of the aims in this renewal will lay a strong foundation for developing the next generation of novel therapeutic anti-infective wound dressings that could greatly speed healing, reduce rates of SSIs and minimize development of antibiotic resistance. We also expect these dressings could serve as effective treatments for traumatic and combat-related injuries.