雷公藤红素纳米胶束通过MAPK信号通路调控巨噬细胞抗角膜新生血管机制研究

Corneal neovascularization (CNV) is a leading cause of visual loss in a number of ophthalmic diseases. And the treatment of CNV is still a challenge for ophthalmologists. We have shown that macrophages can induce CNV by up-regulating VEGF and MMP-9. Also, we have observed topical subconjunctival injection of celastrol nanoparticles is effective in reducing the length and area of CNV accompanying with the decrease in macrophages infiltrated and secreted cytokines, such as MCP-1、VEGF and MMP-9. It suggests that macrophages and secreted cytokines play a critical role in CNV. Meanwhile, celastrol may inhibit CNV through regulating macrophages. However, the mechanism involved of celastrol modulation of CNV is undefined. Many studies have reported that MAPK is an important signal transduction and modulate the secret of several cytokines, such as MCP-1, VEGF and MMP-9 , during various biological processes. And it is reportedly involved in the development of neovascularization. Therefore, we proposed that MAPK signal transduction play a pivotal role in the inhibiting effect of celastrol on macrophages. In this present study, to better improve the hydrophilicity of celastrol, we would like to develop celastrol-loaded poly (ethylene glycol)-block-poly (ε-caprolactone) (PEG-b-PCL) nano-polymeric micelles. And then we will further explore the potential mechanism of celastrol-mediated modulatory effects on macrophages and CNV. It is expected that this study might constitute a deep understanding of the underlying mechanism of CNV development. It will be of help in offering new therapeutic options for CNV and provide a theoretical basis for celastrol application on neovascularization.

角膜新生血管（CNV）是最常见的致盲性原因之一，治疗棘手。我们前期研究表明：巨噬细胞（Mφ）通过上调VEGF和MMP-9诱导CNV产生；结膜下注射雷公藤红素（celastrol ）纳米胶束有效抑制CNV生长，且下调Mφ浸润与MCP-1、VEGF及MMP-9表达。这提示：Mφ及其分泌的细胞因子在CNV形成中起关键作用，Celastrol可能通过调控Mφ抑制CNV生长，但其具体机制尚未明确。据报道MAPK信号通路通过调节MCP-1、VEGF和MMP-9等因子的分泌，促进新生血管形成。我们推测：MAPK信号通路可能在Celastrol调控Mφ抗CNV形成中起重要作用。本课题拟采用纳米技术，构建负载Celastrol的纳米胶束，以增强其水溶性，明确Celastrol在CNV中的作用，探讨其调控Mφ抗CNV的机制，为CNV提供新的治疗途径，为Celastrol治疗新生血管性疾病提供理论依据。

角膜新生血管（CNV）是最常见的致盲性原因之一，治疗棘手。巨噬细胞及其分泌的细胞因子(如VEGF、MMP9)在CNV的形成中发挥关键作用。本课题主要研究雷公藤红素纳米胶束（CNMs）是否通过MAPK信号通路调控巨噬细胞并抑制CNV的发生、发展。本课题制备的CNMs增强了疏水性药物雷公藤红素的表观溶解度，粒径大小约48nm，易于通过眼部的屏障，为进一步研究奠定基础。体外研究证实了：CNMs 下调低氧及炎症诱导巨噬细胞多种血管形成相关因子及炎症因子的表达，进一步研究证实雷公藤红素通过MAPK（P38 MAPK、ERK1/2）信号通路调控下游的转录因子 NF-κB，进而调节趋化因子（MCP-1）、血管形成相关因子（VEGF、MMP9）及炎症因子的表达。同时，我们证实了 CNMs 抑制血管内皮细胞的增殖、迁移、入侵及管样结构形成，进而影响新生血管的发生、发展。体内研究，我们发现CNMs 不仅抑制缝线及碱烧伤诱导角膜新生血管及巨噬细胞浸润，下调角膜组织内VEGF、MMP9的表达。而且抑制激活巨噬细胞诱导的CNV形成，进一步机制研究证实，CNMs 抑制新生血管的功能与抑制其巨噬细胞的分泌有关。本课题采用纳米技术，构建负载雷公藤红素的纳米胶束，以增强其水溶性，提高其生物利用度，明确雷公藤红素在角膜新生血管中的作用。本课题建立了多种角膜新生血管模型，进一步验证 CNMs 对CNV的疗效及机制，探讨其调控巨噬细胞抗CNV的机制，加深了对雷公藤红素治疗CNV 机理的认识，为难治性 CNV乃至新生血管性疾病带来新的治疗途径，为雷公藤红素治疗新生血管性疾病提供理论依据。