美国西奈山伊坎医学院Michael Rendl研究组发现在毛发循环消退期间，真皮鞘收缩增强干细胞的微环境重定位。相关论文于2019年12月19日在线发表在《科学》杂志上。

研究人员确定了位于毛囊下的真皮鞘，这是通过产生向心收缩力的平滑肌收缩机器使组织退化和微环境重新定位的关键驱动力。

研究人员揭示了钙/钙调蛋白/肌球蛋白轻链激酶途径控制鞘膜收缩。当该途径被阻断时，鞘管收缩受到抑制，阻碍了毛囊的消退和生态位的重新定位。

因此，这项研究将真皮鞘鉴定为平滑肌，其可以驱动毛囊消退，从而重新结合微环境和干细胞，进而在体内平衡过程中再生组织结构。

据悉，组织动态平衡需要通过细胞产生和通过细胞丧失而消退的平衡。在毛囊消退的毛发循环中，微环境通过未知机制遍历皮肤，到达干细胞库并触发新的生长。

附：英文原文

Title: Dermal sheath contraction powers stem cell niche relocation during hair cycle regression

Author: Nicholas Heitman, Rachel Sennett, Ka-Wai Mok, Nivedita Saxena, Devika Srivastava, Pieter Martino, Laura Grisanti, Zichen Wang, Avi Ma’ayan, Panteleimon Rompolas, Michael Rendl

Issue&Volume: 2019/12/19

Abstract: Tissue homeostasis requires the balance of growth by cell production and regression through cell loss. In the hair cycle during follicle regression, the niche traverses the skin through an unknown mechanism to reach the stem cell reservoir and trigger new growth. Here we identify the dermal sheath that lines the follicle as the key driver of tissue regression and niche relocation via the smooth muscle contractile machinery that generates centripetal constriction force. We reveal that the calcium/calmodulin/myosin light chain kinase pathway controls sheath contraction. When this pathway is blocked, sheath contraction is inhibited, impeding follicle regression and niche relocation. Thus, our study identifies the dermal sheath as smooth muscle that drives follicle regression for reuniting niche and stem cells in order to regenerate tissue structure during homeostasis.

DOI: 10.1126/science.aax9131

Source: https://science.sciencemag.org/content/early/2019/12/18/science.aax9131