Rodriguez Cetina Biefer Hector, Vasudevan Anju, Elkhal Abdallah
Department of Cardiovascular Surgery, University Hospital Zurich, Zurich, Switzerland.
Angiogenesis and Brain Development Laboratory, Division of Basic Neuroscience, McLean Hospital and Harvard Medical School, Belmont, MA, USA.
Int J Tryptophan Res. 2017 Jun 14;10:1178646917713491. doi: 10.1177/1178646917713491. eCollection 2017.
Increasing evidence underscores the interesting ability of tryptophan to regulate immune responses. However, the exact mechanisms of tryptophan's immune regulation remain to be determined. Tryptophan catabolism via the kynurenine pathway is known to play an important role in tryptophan's involvement in immune responses. Interestingly, quinolinic acid, which is a neurotoxic catabolite of the kynurenine pathway, is the major pathway for the synthesis of nicotinamide adenine dinucleotide (NAD+). Recent studies have shown that NAD+, a natural coenzyme found in all living cells, regulates immune responses and creates homeostasis via a novel signaling pathway. More importantly, the immunoregulatory properties of NAD+ are strongly related to the overexpression of tryptophan hydroxylase 1 (Tph1). This review provides recent knowledge of tryptophan and NAD+ and their specific and intriguing roles in the immune system. Furthermore, it focuses on the mechanisms by which tryptophan regulates NAD+ synthesis as well as innate and adaptive immune responses.
越来越多的证据强调了色氨酸调节免疫反应的有趣能力。然而，色氨酸免疫调节的确切机制仍有待确定。已知通过犬尿氨酸途径的色氨酸分解代谢在色氨酸参与免疫反应中起重要作用。有趣的是，喹啉酸是犬尿氨酸途径的一种神经毒性分解代谢产物，是烟酰胺腺嘌呤二核苷酸（NAD+）合成的主要途径。最近的研究表明，NAD+是一种存在于所有活细胞中的天然辅酶，它通过一条新的信号通路调节免疫反应并建立体内平衡。更重要的是，NAD+的免疫调节特性与色氨酸羟化酶1（Tph1）的过表达密切相关。本综述提供了关于色氨酸和NAD+的最新知识，以及它们在免疫系统中特定而有趣的作用。此外，它还关注色氨酸调节NAD+合成以及先天和适应性免疫反应的机制。
