Department of Pharmaceutical Sciences, Jefferson College of Pharmacy, Thomas Jefferson University, Philadelphia, PA 19107, USA.
Department of Neural Sciences and Center for Substance Abuse Research, Lewis Katz School of Medicine, Temple University, Philadelphia, PA 19140, USA.
Int J Mol Sci. 2022 Feb 18;23(4):2258. doi: 10.3390/ijms23042258.
Omega-3 polyunsaturated fatty acids (n-3 PUFAs), obtained from diet and dietary supplements, have been tested in clinical trials for the prevention or treatment of several diseases. n-3 PUFAs exert their effects by activation of free fatty acid (FFA) receptors. FFA1 receptor, expressed in the pancreas and brain, is activated by medium- to long-chain fatty acids. Despite some beneficial effects on cognition, the effects of n-3 PUFAs on the blood-brain barrier (BBB) are not clearly understood. We examined the effects of FFA1 activation on BBB permeability in vitro, using rat brain microvascular endothelial cells (RBMVEC), and in vivo, by assessing Evans Blue extravasation and by performing live imaging of brain microcirculation in adult rats. AMG837, a synthetic FFA1 agonist, produced a dose-dependent decrease in RBMVEC monolayer resistance assessed with Electric Cell-Substrate Impedance Sensing (ECIS); the effect was attenuated by the FFA1 antagonist, GW1100. Immunofluorescence studies revealed that AMG837 produced a disruption in tight and adherens junction proteins. AMG837 increased Evans Blue content in the rat brain in a dose-dependent manner. Live imaging studies of rat brain microcirculation with miniaturized fluorescence microscopy (miniscope) showed that AMG837 increased extravasation of sodium fluorescein. Taken together, our results demonstrate that FFA1 receptor activation reduced RBMVEC barrier function and produced a transient increase in BBB permeability.
ω-3 多不饱和脂肪酸（n-3PUFAs）可从饮食和膳食补充剂中获得，其已在临床试验中用于预防或治疗多种疾病。n-3PUFAs 通过激活游离脂肪酸（FFA）受体发挥作用。FFA1 受体在胰腺和大脑中表达，可被中长链脂肪酸激活。尽管 n-3PUFAs 对认知有一些有益影响，但它们对血脑屏障（BBB）的影响尚不清楚。我们通过体外检测大鼠脑微血管内皮细胞（RBMVEC）中 FFA1 激活对 BBB 通透性的影响，以及通过评估 Evans Blue 外渗和在成年大鼠中进行脑微循环的活体成像来研究 FFA1 激活对 BBB 通透性的影响。AMG837 是一种合成的 FFA1 激动剂，可剂量依赖性降低使用电细胞-底物阻抗传感（ECIS）评估的 RBMVEC 单层电阻；该作用被 FFA1 拮抗剂 GW1100 减弱。免疫荧光研究显示，AMG837 破坏了紧密连接和黏附连接蛋白。AMG837 以剂量依赖性方式增加了大鼠脑中 Evans Blue 的含量。使用微型荧光显微镜（miniscope）对大鼠脑微循环进行活体成像研究显示，AMG837 增加了荧光素钠的外渗。总之，我们的结果表明，FFA1 受体激活降低了 RBMVEC 屏障功能，并导致 BBB 通透性短暂增加。
