Advanced glycation end products (AGEs) are frequently encountered in a western diet, in addition to their formation in vivo. N-Epsilon-carboxymethyllysine (CML), one of the chemically diverse compounds formed in the reaction between reducing carbohydrates and amines, is often used as a marker of advanced glycation, and has been shown to stimulate serotonin release from cells representing the central (SH-SY5Y cells) and the peripheral (Caco-2 cells) serotonin system in vitro. Here, we investigated the effect of glyoxal, free CML, and protein-linked AGE-BSA on serotonin release from human gastric tumour cells, which originate from an adenocarcinoma of the stomach and have recently been shown to be capable of serotonin synthesis and release. Microarray experiments showed both CML and glyoxal to alter genes associated with serotonin receptors. Furthermore, treatment with glyoxal resulted in a small change in RAGE expression while CML did not alter its expression. On a functional level, treatment with 500 μM CML increased extracellular serotonin content by 341 ± 241%, while treatment with 1 mg mL⁻¹ AGE-BSA led to a reduction by 49 ± 11% compared to non-treated cells. The CML-induced serotonin release was reduced by the HTR3 antagonist granisetron. Incubation with the RAGE antagonist FPS-ZM1 abolished the effect of AGE-BSA on serotonin release, while no impact on CML-induced serotonin release was observed. Furthermore, treatment with 5 mM CML stimulated proton secretion as a functional outcome measure, assessed using a pH sensitive dye. Taken together, these results indicate a likely HTR3-mediated, RAGE-independent effect of free CML on serotonin release and a RAGE-dependent mechanism for the protein linked AGE-BSA.

中文翻译：

---

免费的冲击Ñ ^ε -carboxymethyllysine，它的前体乙二醛和AGE修饰对从培养的人类壁细胞血清素释放BSA

除了在体内形成高级糖化终产物（AGEs）以外，西方饮食中也经常遇到这种情况。N -Epsilon-羧甲基赖氨酸（CML）是在还原性碳水化合物与胺之间的反应中形成的化学上多样化的化合物之一，通常用作高级糖基化的标志物，并且已显示出它可以刺激5-羟色胺从代表中枢（SH）的细胞中释放-SY5Y细胞）和体外（Caco-2细胞）5-羟色胺系统。在这里，我们研究了乙二醛，游离CML和蛋白连接的AGE-BSA对人胃肿瘤细胞血清素释放的影响，该细胞源于胃腺癌，最近被证明能够合成和释放血清素。芯片实验显示，CML和乙二醛均可改变与血清素受体相关的基因。此外，乙二醛处理导致RAGE表达的微小变化，而CML并未改变其表达。在功能水平上，用500μMCML处理可使细胞外血清素含量增加341±241％，而用1 mg mL ^-1处理与未处理的细胞相比，AGE-BSA降低了49±11％。HTR3拮抗剂Granisetron降低了CML诱导的5-羟色胺释放。与RAGE拮抗剂FPS-ZM1一起温育消除了AGE-BSA对5-羟色胺释放的影响，而未观察到对CML诱导的5-羟色胺释放的影响。此外，使用5 mM CML处理可刺激质子分泌，作为功能结局指标，可使用pH敏感染料进行评估。两者合计，这些结果表明游离CML可能对HTR3介导的，不依赖RAGE的作用对5-羟色胺的释放以及与蛋白相关的AGE-BSA的RAGE依赖的机制。