According to the Greek mythology (1), Heracles’ second labor was the destruction of the Lernaean Hydra, a fearsome fire-breathing monster with a dog-like body and nine snake heads. Many had tried to slay the Lernaean Hydra but in vain: Any head that was cut off regrew and multiplied. It is remarkable how consistent the narrative of this myth is with our recent understanding of tissue and organ regeneration. Heracles was successful not only because of his divine origin (he was the son of Zeus after all) and the help of Athena, but particularly because of the assistance he received from his nephew Iolaus, who was assigned the job of cauterizing the exposed stumps of the Hydra’s severed heads. Of course, we now understand why Iolaus’ contribution was so critical: His flame consumed the local stem cells and stopped them from generating a new head! In PNAS, Klimovich et al. (2) go one step further and provide a reasonable explanation as to why the Lernaean Hydra could remain healthy despite inhabiting the dirty waters of an unfathomable Peloponnesian swamp. Using Hydra as the experimental model organism, the authors define the molecular identity of a unique group of neurons that are responsible for the rhythmic contractions of the body and provide insight into the immune mechanisms they (and other neurons) employ to regulate the animal’s microbial environment. These findings reveal remarkable similarities between the pacemaker activities of the Hydra nervous system and the nervous system of the gut in vertebrates (including humans), advancing our understanding of the interaction between microbiota and host organ systems.

中文翻译：

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将神经元与免疫力联系起来：九头蛇的教训。

根据希腊神话（1），赫拉克勒斯的第二项工作是摧毁了莱纳恩·九头蛇（Lernaean Hydra），这是一种令人恐惧的喷火怪兽，具有狗状的身体和九个蛇头。许多人曾试图杀死Lernaean九头蛇，但徒劳无功：任何被割断的脑袋都会再生并繁殖。令人惊讶的是，这个神话的叙述与我们最近对组织和器官再生的理解是多么一致。赫拉克勒斯之所以成功，不仅是因为他的神圣血统（他毕竟是宙斯的儿子）和雅典娜的帮助，而且还特别是因为他的侄子艾奥卢斯（Iolaus）得到了他的帮助，艾奥卢斯（Iolaus）的任务是烧灼裸露的树桩。九头蛇的头部被切断。当然，我们现在知道为什么Iolaus的贡献如此重要：他的火焰消耗了局部干细胞，并阻止了它们产生新的头部！在PNAS中，Klimovich等人。（2）更进一步，并提供合理的解释，说明尽管莱纳河九头蛇栖息在深不可测的伯罗奔尼撒沼泽的肮脏水域中，但为什么仍然可以保持健康。作者使用Hydra作为实验模型有机体，定义了一组独特的神经元的分子同一性，这些神经元负责机体的节律性收缩，并深入了解它们（和其他神经元）用于调节动物微生物环境的免疫机制。 。这些发现揭示了九头蛇神经系统的起搏器活动与脊椎动物（包括人）的肠道神经系统之间的显着相似性，这进一步加深了我们对微生物群与宿主器官系统之间相互作用的理解。