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siRNA对抗p65 NF-kB蛋白，能够在体外恢复炎症单核细胞和其他白细胞中p65 NF-kB基因和蛋白表达的增加。在下一步，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，结肠炎溃疡是一种慢性炎症性肠病，在发达国家发病率很高。第二，目前的治疗方式并不能完全治愈。第三，已知结肠炎溃疡可引起组成性NF-kB激活。在小鼠结肠炎溃疡模型中，静脉应用我们的携带p65 siRNA的磷酸钙纳米颗粒只会减轻炎症作用。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（仅为注射剂量的2%）。因此，在本项目中，我们在之前项目经验的基础上，提供了一种基于siRNA和金纳米颗粒（表示为siRNA- au - nps）的方法，可以进一步发展用于直肠应用治疗结肠炎溃疡。我们期望Au-NPs是治疗结肠炎溃疡的优秀sirna载体，并能很好地接近炎症结肠的促炎细胞。由于我们已经证明包裹在磷酸钙纳米颗粒中的抗p65 siRNA成功地缓解了小鼠的结肠炎，我们将继续通过特定的siRNA靶向p65 NF-kappa B的翻译。从实验角度出发，我们将在不同的分散介质中制备高负载siRNA的超小金纳米颗粒，测定siRNA在炎症粘膜中的生物活性和滞留，评估其在结肠中的抗炎潜力，并揭示其作用机制。因此，这种基于sirna的纳米药物可以为治疗结肠炎溃疡提供有效的工具。

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.