Dynamics of absorption, metabolism, and excretion of 5-aminolevulinic acid in human intestinal Caco-2 cells.
Dynamics of absorption, metabolism, and excretion of 5-aminolevulinic acid in human intestinal Caco-2 cells.
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DOI：
10.1016/j.bbrep.2017.07.006
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发表时间：
2017-09
影响因子：
2.7
通讯作者：
Harigae H
中科院分区：
文献类型：
--
作者：
Saito K;Fujiwara T;Ota U;Hatta S;Ichikawa S;Kobayashi M;Okitsu Y;Fukuhara N;Onishi Y;Ishizuka M;Tanaka T;Harigae H
5-氨基乙酰丙酸(ALA)是合成卟啉和血红素的前体。尽管ALA的口服给药已广泛应用于临床，但其在肠细胞内的吸收、代谢和排泄动力学仍不清楚。在本研究中，在肠细胞分化后，Caco-2细胞与200微米丙氨酸和/或100微米柠檬酸亚铁钠(SFC)孵育72小时，ALA以及ALA和SFC的组合都促进了血红素的合成，而不影响与肠道铁运输有关的基因的表达，如DMT1和FPN。在ALA和SFC的联合作用下，Caco-2细胞的血红素合成的促进作用比在ALA单独作用下更明显，这反映在血红素加氧酶1(HO-1)的诱导表达以及转录辅阻遏子Bach1的蛋白水平降低。染色质免疫沉淀分析证实Bach1染色质位于HO-1的增强子区域，ALA和SFC的加入显著减少了该区域的染色质占有率。最后，对Caco-2细胞的Transwell培养表明，给药到肠腔的ALA部分被转运到血管外侧间隙。这些发现增强了我们对ALA在肠细胞中的吸收和代谢的理解，这可能有助于开发针对各种情况的治疗策略，如贫血。在Caco-2细胞中，ALA和SFC联合使用比单独使用ALA更能促进血红素的合成。血红素通过抑制转录辅阻遏子Bach1在Caco-2细胞中诱导HO-1。ALA加入肠腔后，部分转运到血管外侧间隙。我们的数据增强了对肠细胞中ALA动态的理解。
5-Aminolevulinic acid (ALA) is a precursor for the biosynthesis of porphyrins and heme. Although the oral administration of ALA has been widely applied in clinical settings, the dynamics of its absorption, metabolism, and excretion within enterocytes remain unknown. In this study, after enterocytic differentiation, Caco-2 cells were incubated with 200 µM ALA and/or 100 µM sodium ferrous citrate (SFC) for up to 72 h. Both ALA and the combination of ALA and SFC promoted the synthesis of heme, without affecting the expression of genes involved in intestinal iron transport, such as DMT1 and FPN. The enhanced heme synthesis in Caco-2 cells was more pronounced under the effect of the combination of ALA and SFC than under the effect of ALA alone, as reflected by the induced expression of heme oxygenase 1 (HO-1), as well as a reduced protein level of the transcriptional corepressor Bach1. Chromatin immunoprecipitation analysis confirmed Bach1 chromatin occupancy at the enhancer regions of HO-1, which were significantly decreased by the addition of ALA and SFC. Finally, Transwell culture of Caco-2 cells suggested that the administered ALA to the intestinal lumen was partially transported into vasolateral space. These findings enhance our understanding of the absorption and metabolism of ALA in enterocytes, which could aid in the development of a treatment strategy for various conditions such as anemia. Combination of ALA and SFC promotes heme synthesis than ALA alone in Caco-2 cells. Heme induces HO-1 by inhibiting transcriptional corepressor Bach1 in Caco-2 cells. Addition of ALA to intestinal lumen was partially transported to vasolateral space. Our data enhance the understanding of the dynamics of ALA in enterocytes.