肾衰营养胶囊对CRF营养不良PDLIM7-Nedd4-1信号通路的影响

Chronic renal failure (CRF) has a high morbidity and mortality, which is a serious threat to the health of people. Skeletal muscle atrophy is an important pathological manifestation, but the mechanism is unknown. Our previous studies found that CRF toxin and the state of micro inflammation activated E3 regulate the ubiquitin proteasome system (UPS). The protein is in a state of high decomposition, participating in the occurrence of CRF malnutrition. In previous studies, we found that the PDLIM7- Nedd4-1 is a specific degradation pathway of ubiquitination, but the exact mechanism is not clear. This subject intends to use the PDLIM7- Nedd4-1 signaling pathway as a starting point. Through the establishment of CRF rat model and the model of silence and over expression of PDLIM7 in cells, make sure the role of PDLIM7- Nedd4-1 pathway in the pathogenesis of malnutrition by using the eukaryotic expression system;the in vivo experiment is used to verify the phenotypic effects of the SSYYJN, and the RNAi technique is used to verify the molecular mechanism of its intervention in the treatment of malnutrition in CRF with SSYYJN. This research has important scientific significance.

慢性肾衰竭（CRF）营养不良发病率和死亡率高，严重威胁我国人民健康，骨骼肌萎缩是其重要病理表现，但机制不明，尚无特异性药物治疗。我们前期研究发现CRF状态下毒素和微炎症状态激活E3调控泛素酶体通路（UPS），蛋白质处于高分解状态，参与CRF营养不良的发生。我们在上述研究中又发现，PDLIM7-Nedd4-1信号通路是泛素化的特异性降解途径，但确切的机制还不清楚。本课题拟以PDLIM7-Nedd4-1信号通路为切入点，通过建立CRF营养不良大鼠模型和沉默及过表达PDLIM7细胞模型，运用真核表达系统，确定PDLIM7-Nedd4-1通路在CRF营养不良发病中的作用机制；应用体内实验验证肾衰营养胶囊对模型动物的表型影响；采用RNAi技术体外验证其在肾衰营养胶囊干预CRF营养不良中的分子机制，具有重要的科学意义。

营养不良是慢性肾功能衰竭(chronic renal failure, CRF. 又称慢性肾脏病chronic kidney disease，CKD)常见并发症，是 CRF重要的不良预后影响因素，与骨骼肌蛋白质代谢情况关系密切。目前临床治疗方法单一，国内无知识产权的药物治疗。CRF营养不良所致PEW和骨骼肌萎缩的发生机制尚未清楚，主要由UPS泛素化及自噬等途径调控。最新研究表示PDLIM7- Nedd4-1 信号通路是泛素化的特异性降解途径，但仍待进一步探究。本研究通过对SD大鼠行5/6肾切除术并低蛋白饲料喂养建立CRF营养不良大鼠体内模型，分离大鼠后肢MSC原代培养，分化后TNF-α刺激建立体外肌管萎缩模型，并通过siRNA转染技术建立沉默/过表达模型，研究PDLIM7- Nedd4-1 信号通路与CRF营养不良的关系，和肾衰营养胶囊改善CRF营养不良的作用机制。结果显示：发现PDLIM7/Nedd4-1能下调myostatin表达，上调myoD，改善肌卫星细胞功能；促使PI3K、Akt、FoxO3的磷酸化，下调MuRF1和MaFBX， 抑制肌管蛋白分解，增加肌管内蛋白合成，减轻骨骼肌萎缩；下调炎症因子的表达，减轻CRF微炎症环境对骨骼肌的损伤。还通过AMPK、SKP2、CARM1提高CAT, SOD, GSH-Px抗氧化酶的活性，减少氧化物MDA的生成，改善CRF引起的细胞过度氧化应激和自噬引起的骨骼肌萎缩。