C3a-C3a受体在常染色体显性多囊肾病进展中的作用及机制

Role and mechanism of C3a-C3a receptor in autosomal dominant polycystic kidney disease

目的旨在探讨C3a-C3a受体(C3aR)在常染色体显性多囊肾病(ADPKD)进展中的作用及机制。方法收集ADPKD患者切除肾组织和PKD1敲除小鼠多囊肾组织,观察C3a、C3aR及F4/80在肾组织中的表达;利用脂多糖(LPS)和白细胞介素4(IL-4)分别刺激巨噬细胞,检测各组细胞C3aR、TNF-α、分型标志物和相关信号通路的表达及机制;使用C3aR抑制剂SB290157(1 mg/kg)处理PKD1敲除小鼠,观察肾脏病理、囊肿相关指标和肾功能变化。结果C3a及C3aR在ADPKD患者和PKD1敲除小鼠肾组织中表达显著上调(均P<0.05),C3aR与F4/80共定位于小鼠多囊肾组织中的巨噬细胞上。体外培养M1型巨噬细胞C3aR表达显著上调(P<0.05),C3a刺激后M1型巨噬细胞表达iNOS、TNF-α和IL-6 mRNA显著上调(均P<0.05),分泌TNF-α增多,说明C3a不仅影响M1型巨噬细胞自身炎性因子表达,还影响其周围炎症微环境;此外,C3a激活M1型巨噬细胞Akt信号通路显著上调(P<0.05)。与模型对照组比较,SB290157治疗组小鼠血Scr、BUN水平、囊肿指数、双肾重/体重(2KW/BW)均显著降低(均P<0.05),小鼠肾组织中C3a、C3aR水平及p-ERK、p-P65通路蛋白表达显著下调(均P<0.05)。结论多囊肾组织中增多的C3a通过C3aR引起巨噬细胞浸润和活化,进而促进ADPKD进展,其机制可能通过Akt活化、TNF-α产生增多所致。C3aR拮抗剂是治疗ADPKD的一个潜在研究方向。

Objective To explore the role and mechanism of C3a-C3a receptor(C3aR)in the progression of autosomal dominant polycystic kidney disease(ADPKD).Methods Renal tissues of ADPKD patients and PKD1 knockout mice were collected.Then the expression of C3a-C3aR,Ki67 and F4/80 in renal tissues was observed.Macrophages were stimulated with lipopolysaccharide(LPS)and interleukin 4 respectively.The expression of C3aR,TNF-α,typing markers and related signal pathway proteins was detected in each group.PKD1 knockout mice were treated with C3aR inhibitor SB290157(1 mg/kg).Renal pathology,cyst-related indicators and renal function were observed.Results The expression of C3a and C3aR in ADPKD was up-regulated(both P<0.05);C3aR and F4/80 were co-located in the kidney of polycystic kidney disease(PKD)mice,indicating that C3aR was mainly expressed on membrane of macrophages.In vitro,the expression of C3aR was up-regulated in M1 macrophages(P<0.05).After the stimulation of C3a,the expression of iNOS,TNF-αand IL-6 mRNA in M1 macrophages were up-regulated(all P<0.05),as well as the secretion of TNF-α,indicating that C3a not only affected the expression of inflammatory factors of M1 macrophages,but also affected the inflammatory microenvironment.In addition,C3a significantly activated Akt in M1 macrophages(P<0.05).Compared with the control group,the treatment group showed a decrease in C3a-C3aR as well as serum BUN,Scr,cyst index,and two kidneys weight/body weight(2KW/BW)(all P<0.05),and ADPKD related pathway protein expression such as p-ERK and p-P65 was significantly down-regulated(all P<0.05).Conclusions The increased C3a in polycystic kidney tissue causes infiltration and activation of macrophages through C3aR,and then promotes ADPKD progression.The mechanism may be mediated by Akt activation and increased TNF-αproduction.C3aR antagonist is a potential research direction in the treatment of ADPKD.