肠外营养(PN)相关的胆汁淤积(PNAC)使肠衰竭患者的护理复杂化。在PNAC中,含有植物甾醇的PN与肠道损伤和来自激活的肝巨噬细胞的IL-1β协同作用,以抑制肝细胞法尼醇X受体(FXR)信号并促进PNAC。我们假设FXR的药理学激活将阻止小鼠模型中的PNAC。
诱发PNAC,对雄性C57BL/6小鼠进行肠损伤(2%葡聚糖硫酸钠[DSS]4天),随后进行中心静脉导管插入术,并在有或没有FXR激动剂GW4064的情况下输注PN14天。牺牲之后,肝细胞损伤,炎症,并测定胆汁和固醇转运体的表达。GW4064(30mg/kg/day)在第4-14天添加到PN中,可预防肝损伤和胆汁淤积;逆转H组抑制的核受体亚家族1的mRNA表达,成员4(Nr1h4)/FXR,ATP结合盒亚家族B成员11(Abcb11)/胆盐出口泵,ATP结合盒亚家族C成员2(Abcc2),ATP结合盒亚家族B成员4(Abcb4),和ATP结合盒亚家族G成员5/8(Abcg5/8);和标准化的血清胆汁酸。肝脏染色质免疫沉淀显示GW4064增加了FXR与Abcb11启动子的结合。此外,GW4064可预防DSS-PN诱导的肝巨噬细胞积聚,与巨噬细胞募集和激活相关的基因的肝表达(ll-1b,C-C基序趋化因子受体2,整合素亚基αM,淋巴细胞抗原6复合基因座C),和肝巨噬细胞细胞因子在体外响应脂多糖的转录。在原代小鼠肝细胞中,GW4064激活FXR标准靶标的转录,与IL-1β暴露无关。肠道炎症和回肠mRNA(Nr1h4,Fgf15和有机溶质转运蛋白α)在组间没有差异,在该模型中支持GW4064的肝脏特异性作用。
GW4064通过恢复肝脏FXR信号来预防小鼠的PNAC,导致小管胆汁,固醇和磷脂转运蛋白的表达增加,并抑制巨噬细胞的募集和激活。这些数据支持增强FXR活性作为缓解或预防PNAC的治疗策略。
Parenteral nutrition (PN)-associated cholestasis (PNAC) complicates the care of patients with intestinal failure. In PNAC, phytosterol containing PN synergizes with intestinal injury and IL-1β derived from activated hepatic macrophages to suppress hepatocyte farnesoid X receptor (FXR) signaling and promote PNAC. We hypothesized that pharmacological activation of FXR would prevent PNAC in a mouse model.
To induce PNAC, male C57BL/6 mice were subjected to intestinal injury (2% dextran sulfate sodium [DSS] for 4 days) followed by central venous catheterization and 14-day infusion of PN with or without the FXR agonist GW4064. Following sacrifice, hepatocellular injury, inflammation, and biliary and sterol transporter expression were determined. GW4064 (30 mg/kg/day) added to PN on days 4-14 prevented hepatic injury and cholestasis; reversed the suppressed mRNA expression of nuclear receptor subfamily 1, group H, member 4 (Nr1h4)/FXR, ATP-binding cassette subfamily B member 11 (Abcb11)/bile salt export pump, ATP-binding cassette subfamily C member 2 (Abcc2), ATP binding cassette subfamily B member 4(Abcb4), and ATP-binding cassette subfamily G members 5/8(Abcg5/8); and normalized serum bile acids. Chromatin immunoprecipitation of liver showed that GW4064 increased FXR binding to the Abcb11 promoter. Furthermore, GW4064 prevented DSS-PN-induced hepatic macrophage accumulation, hepatic expression of genes associated with macrophage recruitment and activation (ll-1b, C-C motif chemokine receptor 2, integrin subunit alpha M, lymphocyte antigen 6 complex locus C), and hepatic macrophage cytokine transcription in response to lipopolysaccharide in vitro. In primary mouse hepatocytes, GW4064 activated transcription of FXR canonical targets, irrespective of IL-1β exposure. Intestinal inflammation and ileal mRNAs (Nr1h4, Fgf15, and organic solute transporter alpha) were not different among groups, supporting a liver-specific effect of GW4064 in this model.
GW4064 prevents PNAC in mice through restoration of hepatic FXR signaling, resulting in increased expression of canalicular bile and of sterol and phospholipid transporters and suppression of macrophage recruitment and activation. These data support augmenting FXR activity as a therapeutic strategy to alleviate or prevent PNAC.