Exposure to lipopolysaccharide and/or unconjugated bilirubin impair the integrity and function of brain microvascular endothelial cells.
Exposure to lipopolysaccharide and/or unconjugated bilirubin impair the integrity and function of brain microvascular endothelial cells.
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DOI：
10.1371/journal.pone.0035919
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发表时间：
2012
期刊：
影响因子：
3.7
通讯作者：
Brito MA
中科院分区：
文献类型：
--
作者：
Cardoso FL;Kittel A;Veszelka S;Palmela I;Tóth A;Brites D;Deli MA;Brito MA
败血症和黄疸是新生儿常见的疾病，可导致脑损伤。虽然脂多糖（LPS）已知可改变血脑屏障（BBB）的完整性，但对未结合胆红素（UCB）的影响知之甚少，对UCB和LPS对脑微血管内皮细胞（BMEC）的联合作用更是知之甚少。在100 µM人血清白蛋白存在下，用1 µg/ml LPS和/或50 µM UCB处理原代大鼠BMEC单层4或24 h。在选定的实验中使用BMEC与星形胶质细胞的共培养物，一种更复杂的BBB模型。LPS导致细胞凋亡，UCB诱导凋亡和坏死样细胞死亡。LPS和UCB可抑制P-糖蛋白的表达，激活基质金属蛋白酶-2和-9。透射电子显微镜证实凋亡小体，以及受损的线粒体和粗面内质网在BMEC的任何侮辱。较短的细胞接触和增加的小窝样内陷在LPS处理的细胞中是明显的，并且在用UCB处理后观察到细胞间连接的丧失。这两种化合物均在单培养物和共培养物中引发内皮渗透性和跨内皮电阻的损害。通过连接蛋白β-catenin、ZO-1和claudin-5的免疫染色改变证实了功能变化。LPS和UCB作用后，BMEC细胞间隙扩大，连接蛋白重新分布。LPS和/或UCB对BMEC产生直接毒性作用，具有不同的时间特征和作用机制。因此，在暴露于这些神经毒素时，脑内皮完整性受损可能有利于它们进入大脑，从而增加损伤的风险，并需要在新生儿期对败血症和黄疸进行充分的临床管理。
Sepsis and jaundice are common conditions in newborns that can lead to brain damage. Though lipopolysaccharide (LPS) is known to alter the integrity of the blood-brain barrier (BBB), little is known on the effects of unconjugated bilirubin (UCB) and even less on the joint effects of UCB and LPS on brain microvascular endothelial cells (BMEC). Monolayers of primary rat BMEC were treated with 1 µg/ml LPS and/or 50 µM UCB, in the presence of 100 µM human serum albumin, for 4 or 24 h. Co-cultures of BMEC with astroglial cells, a more complex BBB model, were used in selected experiments. LPS led to apoptosis and UCB induced both apoptotic and necrotic-like cell death. LPS and UCB led to inhibition of P-glycoprotein and activation of matrix metalloproteinases-2 and -9 in mono-cultures. Transmission electron microscopy evidenced apoptotic bodies, as well as damaged mitochondria and rough endoplasmic reticulum in BMEC by either insult. Shorter cell contacts and increased caveolae-like invaginations were noticeable in LPS-treated cells and loss of intercellular junctions was observed upon treatment with UCB. Both compounds triggered impairment of endothelial permeability and transendothelial electrical resistance both in mono- and co-cultures. The functional changes were confirmed by alterations in immunostaining for junctional proteins β-catenin, ZO-1 and claudin-5. Enlargement of intercellular spaces, and redistribution of junctional proteins were found in BMEC after exposure to LPS and UCB. LPS and/or UCB exert direct toxic effects on BMEC, with distinct temporal profiles and mechanisms of action. Therefore, the impairment of brain endothelial integrity upon exposure to these neurotoxins may favor their access to the brain, thus increasing the risk of injury and requiring adequate clinical management of sepsis and jaundice in the neonatal period.
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2.9
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