Enteric nanomedicine for targeted silencing of NF-kappa B gene products in colitis ulcerosa

在之前的研究项目中，我们已经证明，磷酸钙纳米颗粒携带针对p65 NF-kB蛋白的siRNA能够在体外逆转炎症单核细胞和其他白细胞中增加的p65 NF-kB基因和蛋白表达。在下一步中，我们评估了携带siRNA的磷酸钙纳米颗粒在结肠炎小鼠模型中的治疗效果，因为：首先，溃疡性结肠炎是一种慢性炎症性肠病，在发达国家发病率很高。第二，目前的治疗方式不能完全治愈。第三，已知溃疡性结肠炎引起组成性NF-κ B活化。在溃疡性结肠炎的鼠模型中，静脉内应用我们的携带p65 siRNA的磷酸钙纳米颗粒仅导致炎症的减轻作用。我们将这一发现归因于只有一小部分功能性纳米颗粒到达结肠（只有注射剂量的2%）。因此，在这个项目中，我们建立了我们在前一个项目中的经验，并提供了一种基于siRNA和金纳米颗粒（表示为siRNA-Au-NPs）的方法，可以进一步开发用于通过直肠应用治疗溃疡性结肠炎。我们期望Au-NPs是用于治疗溃疡性结肠炎的优良siRNA载体，并且引起对发炎结肠的促炎细胞的良好可及性。由于我们已经证明包封在磷酸钙纳米颗粒中的抗p65 siRNA成功地减轻了小鼠结肠炎，我们将继续通过特异性siRNA靶向p65 NF-κ B翻译。从实验的角度来看，我们将在不同的分散介质中制备具有高载量siRNA的超小金纳米颗粒，确定siRNA的生物活性，在发炎粘膜的保留，评估结肠中的抗炎潜力并揭示作用机制。因此，这种基于siRNA的纳米药物可以为治疗溃疡性结肠炎提供有效的工具。

In the preceding research project, we have shown that calcium phosphate nanoparticles carrying siRNA against the p65 NF-kB protein are able to revert the increased p65 NF-kB gene and protein expression in inflamed monocytes and other leucocytes in vitro. In the next step, we assessed the therapeutic efficacy of the calcium phosphate nanoparticles carrying siRNA in a mouse model of colitis, since: First, colitis ulcerosa is a chronic inflammatory bowel disease with high incidence in developed countries. Second, the current treatment modalities do not lead to a complete cure. Third, colitis ulcerosa is known to elicit a constitutive NF-kB activation. In the murine model of colitis ulcerosa, the intravenous application of our calcium phosphate nanoparticles carrying p65 siRNA led only to alleviated effects of inflammation. We attribute this finding to the fact that only a small part of the functional nanoparticles reached the colon (only 2% of the injected dose). Therefore, in this project, we build up on our experience in the preceding project and provide an approach based on siRNA and gold nanoparticles (denoted as siRNA-Au-NPs), which can be further developed for the treatment of colitis ulcerosa via rectal application. We expect that the Au-NPs are excellent siRNA-carriers for the treatment of colitis ulcerosa and elicit a good accessibility to pro-inflammatory cells of the inflamed colon. Since we have shown that anti-p65 siRNA encapsulated into calcium phosphate nanoparticles successfully alleviated colitis in mice, we will continue targeting p65 NF-kappa B translation by specific siRNAs. From the experimental point of view, we will prepare ultra-small gold nanoparticles with a high loading of siRNA in different dispersion media, determine the siRNA bioactivity, the retention at the inflamed mucosa, assess the anti-inflammatory potential in the colon and unveil the mechanisms of action. Consequently, this siRNA-based nanomedicine could provide an effective tool for the treatment of colitis ulcerosa.