In vivo and ex vivo regulation of breast cancer resistant protein (Bcrp) by peroxisome proliferator-activated receptor alpha (Pparα) at the blood-brain barrier.
In vivo and ex vivo regulation of breast cancer resistant protein (Bcrp) by peroxisome proliferator-activated receptor alpha (Pparα) at the blood-brain barrier.
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DOI：
10.1111/jnc.13389
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发表时间：
2015-12
影响因子：
4.7
通讯作者：
Bendayan R
中科院分区：
文献类型：
--
作者：
Hoque MT;Shah A;More V;Miller DS;Bendayan R
位于血脑屏障（BBB）的乳腺癌抵抗蛋白（Bcrp/Abcg2）限制了许多外源性药物（包括药理学药物）进入大脑的通透性。过氧化物酶体增殖体激活受体α (Pparα)是一种配体激活的转录因子，主要参与脂质代谢，已被证明可以调节人脑微血管内皮细胞（hCMEC/D3）中Bcrp的功能表达。本研究的目的是在体外和体内研究Pparα在完整血脑屏障中对Bcrp的调节。体外实时定量PCR和免疫印迹分析显示，与Pparα配体clofibrate孵育的CD-1小鼠脑毛细血管中Abcg2/Bcrp mRNA和蛋白水平显著上调。CD-1和C57BL/6脑毛细血管的荧光转运试验显示，暴露于clofibrate显著增加Bcrp的转运活性。在Pparα敲除小鼠分离的毛细血管中没有观察到这种增加。在体内实验中，我们发现：1)在clofibrate剂量的CD-1和C57BL/6毛细血管裂解物中，Bcrp蛋白显著上调，但在Pparα敲除的毛细血管裂解物中没有影响；2)在clofibrate处理小鼠的毛细血管中，Bcrp转运活性显著增加。这些结果表明Pparα在脑毛细血管中增加了Bcrp的功能表达，提示Pparα是另一种参与血脑屏障膜外排转运体和药物通透性调节的核受体。血脑屏障（BBB）的乳腺癌抵抗蛋白（Bcrp）限制了异种生物进入大脑的渗透性。在此，我们提供了第一个证据，与对照组（A， C）相比，氯贝特（一种已建立的配体）激活过氧化物酶体增殖体激活的核受体α (Pparα)，分别上调了Bcrp在小鼠脑毛细血管中的表达(B)和功能(D)。这些结果表明，Pparα可能参与血脑屏障的膜外排转运蛋白和药物通透性的调节。
Breast cancer resistance protein (Bcrp/Abcg2) localized at the blood-brain barrier (BBB) limits permeability into the brain of many xenobiotics, including pharmacological agents. Peroxisome proliferator-activated receptor α (Pparα), a ligand-activated transcription factor, primarily involved in lipid metabolism, has been shown to regulate the functional expression of Bcrp in human cerebral microvascular endothelial cells (hCMEC/D3). The aim of this study was to investigate ex vivo and in vivo, the regulation of Bcrp by Pparα in an intact BBB. Ex vivo quantitative real-time PCR and immunoblot analyses showed significant upregulation of Abcg2/Bcrp mRNA and protein levels in CD-1 mouse brain capillaries incubated with clofibrate, a Pparα ligand. Fluorescence-based transport assays in CD-1 and C57BL/6 brain capillaries showed that exposure to clofibrate significantly increased Bcrp transport activity. This increase was not observed in capillaries isolated from Pparα knockout mice. In vivo, we found: i) significant Bcrp protein upregulation in clofibrate dosed CD-1 and C57BL/6 capillary lysates but no effect in Pparα knockout capillary lysates, and ii) significantly increased Bcrp transport activity in capillaries isolated from clofibrate treated mice. These results demonstrate an increase in Bcrp functional expression by Pparα in brain capillaries, and suggest that Pparα is another nuclear receptor that can contribute to the regulation of membrane efflux transporters and drug permeability at the BBB. Breast cancer resistance protein (Bcrp) at the blood brain barrier (BBB) limits xenobiotics permeability into the brain. Herein, we provide first evidence that compared to controls (A, C), activation of peroxisome proliferator-activated nuclear receptor α (Pparα) by clofibrate, an established ligand, upregulates the expression (B) and function (D) of Bcrp in mice brain capillaries, respectively. These results suggest that Pparα can contribute to the regulation of membrane efflux transporters and drug permeability at the BBB.