美国索尔克生物研究所的Martin W. Hetzer团队取得一项新进展，他们发现不同成体组织中的细胞寿命非常不同，从而形成了一种被命名为“年龄马赛克”的模式。2019年8月国际知名学术期刊《细胞—代谢》发表了这一成果。

为了研究成体组织中细胞和蛋白质的寿命，研究人员开发了将同位素小鼠标记与混合成像相结合的方法（MIMS-EM）。利用氮15定位，研究人员发现肝脏和胰腺是由年龄相差很大的细胞组成的，许多细胞的年龄和动物一样大。引人注目的是，研究人员还发现，以其复制潜能著名的成纤维细胞和内皮细胞中存在一个亚群，其特征是在成年期没有出现细胞分裂。此外，研究人员还发现胰岛B细胞和神经元的初级纤毛含有寿命相差很大的不同结构区域。基于这些发现，研究人员认为跨多个尺度的年龄嵌合是成体组织、细胞和蛋白质复合物组成的基本原则。

据悉，大多数神经元在动物的一生中不会被替换。这种不分裂状态的特征是极端的长寿和关键调控蛋白的年龄依赖性下降。

 

附：英文原文

Title: Age Mosaicism across Multiple Scales in Adult Tissues

Author: Rafael Arrojo e Drigo, Varda Lev-Ram, Swati Tyagi, Ranjan Ramachandra, Thomas Deerinck, Eric Bushong, Sebastien Phan, Victoria Orphan, Claude Lechene, Mark H. Ellisman, Martin W. Hetzer

Issue&Volume: Volume 30 Issue 2

Abstract: Most neurons are not replaced during an animal’s lifetime. This nondividing state is characterized by extreme longevity and age-dependent decline of key regulatory proteins. To study the lifespans of cells and proteins in adult tissues, we combined isotope labeling of mice with a hybrid imaging method (MIMS-EM). Using 15N mapping, we show that liver and pancreas are composed of cells with vastly different ages, many as old as the animal. Strikingly, we also found that a subset of fibroblasts and endothelial cells, both known for their replicative potential, are characterized by the absence of cell division during adulthood. In addition, we show that the primary cilia of beta cells and neurons contains different structural regions with vastly different lifespans. Based on these results, we propose that age mosaicism across multiple scales is a fundamental principle of adult tissue, cell, and protein complex organization.

DOI: https://doi.org/10.1016/j.cmet.2019.05.010

Source: https://www.cell.com/cell-metabolism/fulltext/S1550-4131(19)30250-5