Resting no more: re-defining telogen, the maintenance stage of the hair growth cycle.
Resting no more: re-defining telogen, the maintenance stage of the hair growth cycle.
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DOI：
10.1111/brv.12151
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发表时间：
2015-11
影响因子：
--
通讯作者：
Paus R
中科院分区：
文献类型：
--
作者：
Geyfman M;Plikus MV;Treffeisen E;Andersen B;Paus R
毛囊代表了一个典型的外胚层-中胚层相互作用系统，在这个系统中可以研究现代生物学的中心问题。这些富含干细胞的微型器官的一个独特特征是，它们在活跃再生(生长期)、凋亡退化(退化期)和相对增殖停滞期(终止期)之间经历了长达一生的周期性转换。由于休眠期间HF的增殖率较低，体积较小，所以通常认为这一阶段是休眠阶段。然而，多条新出现的证据表明，端原期间的高频丝毫不是处于休眠状态。在这里，我们强调，端粒酶原是哺乳动物毛皮的一种高能效默认状态，其功能集中在维持毛发纤维并迅速对其丢失做出反应。在以最小的能量消耗积极保留毛发纤维的同时，telogen HFs可以启动新的再生周期，以响应来自其自主微环境(包括其干细胞利基)以及外部组织宏观环境的各种刺激。端原HFs的再生反应随时间的变化而变化，可分为两个亚阶段：早期的“难治”阶段和晚期的“胜任”阶段。这些变化的活动反映在端原皮肤中数百个动态调节的基因上，可能是为了建立一个对创伤和其他皮肤动态平衡紊乱的快速反应信号环境。此外，在生长期和后续器官再生的关键阶段，通过抑制毛发生长的分子刹车，激活促再生信号，端粒素是昼夜节律输出的解释者。因此，端粒酶原可以作为一个很好的模型系统，用于解剖组织重塑的主动‘再生模式’之前的信号和细胞相互作用。这一修改后的对端原生物学的理解也指出了在管理常见的人类头发生长疾病方面有趣的新的治疗途径。
The hair follicle (HF) represents a prototypic ectodermal–mesodermal interaction system in which central questions of modern biology can be studied. A unique feature of these stem-cell-rich mini-organs is that they undergo life-long, cyclic transformations between stages of active regeneration (anagen), apoptotic involution (catagen), and relative proliferative quiescence (telogen). Due to the low proliferation rate and small size of the HF during telogen, this stage was conventionally thought of as a stage of dormancy. However, multiple lines of newly emerging evidence show that HFs during telogen are anything but dormant. Here, we emphasize that telogen is a highly energy-efficient default state of the mammalian coat, whose function centres around maintenance of the hair fibre and prompt responses to its loss. While actively retaining hair fibres with minimal energy expenditure, telogen HFs can launch a new regeneration cycle in response to a variety of stimuli originating in their autonomous micro-environment (including its stem cell niche) as well as in their external tissue macro-environment. Regenerative responses of telogen HFs change as a function of time and can be divided into two sub-stages: early ‘refractory’ and late ‘competent’ telogen. These changing activities are reflected in hundreds of dynamically regulated genes in telogen skin, possibly aimed at establishing a fast response-signalling environment to trauma and other disturbances of skin homeostasis. Furthermore, telogen is an interpreter of circadian output in the timing of anagen initiation and the key stage during which the subsequent organ regeneration (anagen) is actively prepared by suppressing molecular brakes on hair growth while activating pro-regenerative signals. Thus, telogen may serve as an excellent model system for dissecting signalling and cellular interactions that precede the active ‘regenerative mode’ of tissue remodeling. This revised understanding of telogen biology also points to intriguing new therapeutic avenues in the management of common human hair growth disorders.
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影响因子：
4.8
作者：
Arck, PC;Handjiski, B;Paus, R
通讯作者：
Paus, R
影响因子：
3.7
作者：
BULLOUGH, WS;LAURENCE, EB;HEWETT, CL
通讯作者：
HEWETT, CL
影响因子：
23.9
作者：
Brownell, Isaac;Guevara, Elizabeth;Bai, C. Brian;Loomis, Cynthia A.;Joyner, Alexandra L.
通讯作者：
Joyner, Alexandra L.
影响因子：
4
作者：
Alonso, L;Fuchs, E
通讯作者：
Fuchs, E
影响因子：
1.7
作者：
Adly, Mohamed A.;Assaf, Hanan A.;Hussein, Mahmoud Rezk A.
通讯作者：
Hussein, Mahmoud Rezk A.