基于高效肾靶向的溶菌酶-Bardoxolone偶联物治疗急性肾损伤研究

Acute Kidney Injury (AKI) is a kind of severe crisis, which is caused by a variety of clinical diseases and which is the primary complications in hospital with high mortality. There is no effective treatment drugs for AKI currently in clinical. Renal targeted therapy drug represents a promising technology, and the development of targeting drug delivery system of the kidneys can increase the drug concentration in the kidneys, have a good treatment, and reduce toxicity. Bardoxolone has been now selected as a model drug compound, which was recognized therapeutic potential of AKI. Bardoxolone is an anti-inflammatory, anti-oxidant, by activating the Keap1 / Nrf2 pathway ,which play a protective role in the kidney in AKI. Lysozyme as carrier selection, Bardoxolone-lysozyme conjugates synthesis and complete its physical and chemical properties and Quality Evaluation. Studies in vitro test Conjugates in the kidney proximal tubule epithelial cells uptake and metabolism in normal animals with kidney distribution targeting accuracy. Furthermore It is clear that conjugate therapeutic effects in Nrf2-KO mouse model of AKI. Eventually the strategies that have been employed to develop kidney-targeted drug delivery systems, Bardoxolone-lysozyme conjugates, increase renal local efficacy and reduce systemic side effects. It present promising strategies to achieve the goal of targeting drugs to the kidney.

急性肾损伤（Acute Kidney Injury，AKI）是临床常见的急危重症，病死率高，消耗大量医疗资源。目前临床上没有成熟、有效的AKI治疗药物。研发肾靶向治疗药物提高肾脏有效药物浓度和治疗效果，降低毒副作用是一种有前途的治疗策略。本项目选用国际上公认有AKI治疗前景的化合物Bardoxolone为模型药物，Bardoxolone是一种抗炎、抗氧化剂，通过激活Keap1/Nrf2 通路在AKI治疗中发挥肾脏保护作用。选用溶菌酶为载体，合成溶菌酶-Bardoxolone偶联物，完成其理化性质与质量评估研究。研究其在肾脏肾小管上皮细胞的摄取及代谢，在正常动物体内分布与肾脏靶向精度，明确偶联物对Nrf2-KO小鼠AKI模型的治疗效果。最终使Bardoxolone药物直接作用损伤的肾脏，增加肾脏局部疗效，减轻全身毒副作用。真正做到肾脏的精准靶向治疗，建立肾脏靶向治疗AKI的关键技术平台。

急性肾损伤是常见的急危重症，发病率高，死亡率高，缺乏有效的预防措施。如何改善AKI的发病率及死亡率，寻找新的、针对AKI的靶向治疗方法，提高急性肾损伤的治愈率是关注的重大科学问题。.本项目选用国际上公认有AKI治疗前景的化合物Bardoxolone（CDDO）为模型药物，CDDO是一种抗炎、抗氧化剂，在AKI发挥肾脏的保护作用。但应用Bardoxolone的病人心血管事件率较高，这就提示我们如果应用精准肾脏靶向载体把药物直接“运送”到肾脏，在AKI治疗作用的同时，减轻其他脏器（如心衰的发生）的副作用。选用溶菌酶（肾脏靶向）为载体，通过肾靶向载体来提高Bardoxolone在肾脏的浓度、同时降低心脏的药物分布，可望大大降低其心血管副作用。.首先合成溶菌酶-Bardoxolone偶联物，完成理化性质与质量评估研究。在体外细胞水平评估了CDDO及CDDO-LZM偶联药物对HK-2细胞的毒性作用，与CDDO相比，偶联物显示出更好的安全性。利用C57BL/6小鼠建立IR-AKI模型，病理染色及血生化结果显示，偶联药物与10倍剂量CDDO单体两组治疗组小鼠病理损伤轻于对照组，肾损伤因子Kim1表达降低，证实偶联药物具有AKI良好治疗效果。Tunel染色和Bax等凋亡相关指标结果显示，药物治疗能抑制细胞凋亡，减轻模型小鼠肾脏损伤。机制研究显示，溶菌酶- CDDO肾脏靶向偶联药物（CDDO-LZM）通过减轻氧化应激损伤，上调氧化应激转录因子2（Nuclear factor-E2 related factor 2，Nrf2）的表达，发挥治疗作用。在证明心脏减毒方面，给予AKI模型小鼠偶联药物及单体药物尾静脉注射，2周后留取心脏组织。IR-CDDO-LZM组小鼠心肌损伤明显低于单体组小鼠：包括射血分数改善、心率降低、左室短轴缩短率（LVFS）增高。结果表明偶联药物在发挥疗效的同时能够减轻Bardoxolone单体治疗带来的心脏毒副作用。.本项目最终得到的溶菌酶-Bardoxolone肾脏靶向偶联药物，通过Nrf2通路的抗氧化机制发挥对AKI模型小鼠的治疗效果。同时心脏毒副作用低，是非常有前景的肾脏靶向药物。共发表论文15篇，其中SCI论文10篇，核心期刊5篇，项目负责人获得2020年全国创新争先奖牌创新团队（核心成员）。建立了肾脏靶向治疗AKI的关键技术平台。