Introduction

Biomaterials can provide localized reservoirs for controlled release of therapeutic biomolecules and drugs for applications in tissue engineering and regenerative medicine. As carriers of gene-based therapies, biomaterial scaffolds can improve efficiency and delivery-site localization of transgene expression. Controlled delivery of gene therapy vectors from scaffolds requires cell-scale macropores to facilitate rapid host cell infiltration. Recently, advanced methods have been developed to form injectable scaffolds containing cell-scale macropores. However, relative efficacy of in vivo gene delivery from scaffolds formulated using these general approaches has not been previously investigated. Using two of these methods, we fabricated scaffolds based on hyaluronic acid (HA) and compared how their unique, macroporous architectures affected their respective abilities to deliver transgenes via lentiviral vectors in vivo.

Methods

Three types of scaffolds—nanoporous HA hydrogels (NP-HA), annealed HA microparticles (HA-MP) and nanoporous HA hydrogels containing protease-degradable poly(ethylene glycol) (PEG) microparticles as sacrificial porogens (PEG-MP)—were loaded with lentiviral particles encoding reporter transgenes and injected into mouse mammary fat. Scaffolds were evaluated for their ability to induce rapid infiltration of host cells and subsequent transgene expression.

Results

Cell densities in scaffolds, distances into which cells penetrated scaffolds, and transgene expression levels significantly increased with delivery from HA-MP, compared to NP-HA and PEG-MP, scaffolds. Nearly 8-fold greater cell densities and up to 16-fold greater transgene expression levels were found in HA-MP, over NP-HA, scaffolds. Cell profiling revealed that within HA-MP scaffolds, macrophages (F4/80+), fibroblasts (ERTR7+) and endothelial cells (CD31+) were each present and expressed delivered transgene.

Conclusions

Results demonstrate that injectable scaffolds containing cell-scale macropores in an open, interconnected architecture support rapid host cell infiltration to improve efficiency of biomaterial-mediated gene delivery.

中文翻译：

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用于基因传递的具有大孔结构的可注射透明质酸支架。

介绍

生物材料可以提供局部储存库，用于控制释放治疗性生物分子和药物，用于组织工程和再生医学。作为基因疗法的载体，生物材料支架可以提高转基因表达的效率和递送位点定位。从支架上受控地递送基因治疗载体需要细胞级大孔以促进宿主细胞的快速浸润。最近，已经开发出先进的方法来形成含有细胞级大孔的可注射支架。然而，之前尚未研究过使用这些通用方法配制的支架的体内基因递送的相对功效。使用其中两种方法，我们制造了基于透明质酸（HA）的支架，并比较了它们独特的大孔结构如何影响它们各自通过慢病毒载体在体内传递转基因的能力。

方法

加载了三种类型的支架——纳米孔HA水凝胶(NP-HA)、退火HA微粒(HA-MP)和含有蛋白酶可降解聚乙二醇(PEG)微粒作为牺牲致孔剂的纳米孔HA水凝胶(PEG-MP)将编码报告转基因的慢病毒颗粒注射到小鼠乳腺脂肪中。评估了支架诱导宿主细胞快速浸润和随后转基因表达的能力。

结果

与 NP-HA 和 PEG-MP 支架相比，HA-MP 支架中的细胞密度、细胞穿透支架的距离以及转基因表达水平显着增加。与 NP-HA 支架相比，HA-MP 支架中的细胞密度高出近 8 倍，转基因表达水平高出 16 倍。细胞分析显示，在 HA-MP 支架内，巨噬细胞 (F4/80+)、成纤维细胞 (ERTR7+) 和内皮细胞 (CD31+) 均存在并表达传递的转基因。

结论

结果表明，在开放、互连的结构中含有细胞级大孔的可注射支架支持快速宿主细胞渗透，以提高生物材料介导的基因传递的效率。