小柯机器人

西班牙巴塞罗那科技学院Arnau Sebé-Pedrós研究组揭示早期动物演化中神经元基因表达程序的逐步出现。这一研究成果于2023年9月19日在线发表在国际学术期刊《细胞》上。

研究人员通过揭示胎生动物等非两栖动物来重建了这一过程。这些盘状小动物不仅有九种形态学上描述的细胞类型，没有神经元，而且还表现出由分泌肽的细胞引发的协调行为。研究人员在四种胎生动物中使用系统发生学、染色质图谱分析和比较单细胞基因组学揭示了这些肽能细胞可能与神经元的亲缘关系。研究人员发现胎生动物的细胞类型表达程序是一致的，包括转分化细胞群和循环细胞群，这表明细胞类型处于活跃的平衡状态。

研究人员还发现了14种表达神经元相关成分（如突触前支架）的肽能细胞类型，它们来自具有神经发生特征的祖细胞。相比之下，海绵和栉水母等早期分支动物则缺乏这种保守表达。这些研究结果表明，关键的神经元发育和效应基因模块是在刺胞动物/两侧对称动物的神经元出现之前，在旁分泌细胞信号的背景下演化而来的。

据介绍，神经元和其他主要细胞类型程序的组装发生在动物演化的早期。

附：英文原文

Title: Stepwise emergence of the neuronal gene expression program in early animal evolution

Author: Sebastián R. Najle, Xavier Grau-Bové, Anamaria Elek, Cristina Navarrete, Damiano Cianferoni, Cristina Chiva, Didac Caas-Armenteros, Arrate Mallabiabarrena, Kai Kamm, Eduard Sabidó, Harald Gruber-Vodicka, Bernd Schierwater, Luis Serrano, Arnau Sebé-Pedrós

Issue&Volume: 2023-09-19

Abstract: The assembly of the neuronal and other major cell type programs occurred early in animal evolution. We can reconstruct this process by studying non-bilaterians like placozoans. These small disc-shaped animals not only have nine morphologically described cell types and no neurons but also show coordinated behaviors triggered by peptide-secreting cells. We investigated possible neuronal affinities of these peptidergic cells using phylogenetics, chromatin profiling, and comparative single-cell genomics in four placozoans. We found conserved cell type expression programs across placozoans, including populations of transdifferentiating and cycling cells, suggestive of active cell type homeostasis. We also uncovered fourteen peptidergic cell types expressing neuronal-associated components like the pre-synaptic scaffold that derive from progenitor cells with neurogenesis signatures. In contrast, earlier-branching animals like sponges and ctenophores lacked this conserved expression. Our findings indicate that key neuronal developmental and effector gene modules evolved before the advent of cnidarian/bilaterian neurons in the context of paracrine cell signaling.

DOI: 10.1016/j.cell.2023.08.027

Source: https://www.cell.com/cell/fulltext/S0092-8674(23)00917-0