5-methoxytryptophan (5-MTP) is an endothelial factor with anti-inflammatory properties. It is synthesized from L-tryptophan via two enzymatic steps: tryptophan hydroxylase-1 (TPH-1) and hydroxyindole O-methyltransferase. Lipopolysaccharide (LPS) and pro-inflammatory cytokines suppress endothelial 5-MTP production by inhibiting TPH-1 expression. 5-MTP protects endothelial barrier function and promotes endothelial repair, while it blocks vascular smooth muscle cell migration and proliferation by inhibiting p38 MAPK activation. 5-MTP controls macrophage transmigration and activation by inhibiting p38 MAPK and NF-κB activation. 5-MTP administration attenuates arterial intimal hyperplasia, defends against systemic inflammation and prevents renal fibrosis in relevant murine models. Serum 5-MTP level is depressed in human sepsis as well as in mice with sepsis-like disorder. It is reduced in chronic kidney disease and acute myocardial infarction in humans. The reported data suggest that serum 5-MTP may be a theranostic biomarker. In summary, 5-MTP represents a new class of tryptophan metabolite which defends against inflammation and inflammation-mediated tissue damage and fibrosis. It may be a valuable lead compound for developing new drugs to treat complex human inflammatory disorders.

中文翻译：

---

5-甲氧基色氨酸：抗血管损伤和炎症的武器库。

5-甲氧基色氨酸（5-MTP）是具有抗炎特性的内皮因子。它是通过两个酶促步骤从L-色氨酸合成的：色氨酸羟化酶-1（TPH-1）和羟吲哚O-甲基转移酶。脂多糖（LPS）和促炎细胞因子可通过抑制TPH-1表达来抑制内皮5-MTP的产生。5-MTP保护内皮屏障功能并促进内皮修复，同时通过抑制p38 MAPK活化来阻止血管平滑肌细胞迁移和增殖。5-MTP通过抑制p38 MAPK和NF-κB活化来控制巨噬细胞的转运和活化。在相关的小鼠模型中，使用5-MTP可以减轻动脉内膜增生，防御全身炎症并预防肾纤维化。在人败血症以及患有败血症样疾病的小鼠中，血清5-MTP水平降低。在人类的慢性肾脏疾病和急性心肌梗塞中减少。报道的数据表明血清5-MTP可能是治疗诊断的生物标志物。总之，5-MTP代表了一类新型的色氨酸代谢产物，可防御炎症以及炎症介导的组织损伤和纤维化。它可能是开发治疗复杂人类炎性疾病的新药的有价值的先导化合物。