Li Ang, Lai Yung-Chih, Figueroa Seth, Yang Tian, Widelitz Randall B, Kobielak Krzysztof, Nie Qing, Chuong Cheng Ming
Department of Pathology, University of Southern California, Los Angeles, California.
Center for Developmental Biology and Regenerative Medicine, Taiwan University, Taipei, Taiwan.
Dev Dyn. 2015 Aug;244(8):905-20. doi: 10.1002/dvdy.24281. Epub 2015 Jul 6.
How tissue patterns form in development and regeneration is a fundamental issue remaining to be fully understood. The integument often forms repetitive units in space (periodic patterning) and time (cyclic renewal), such as feathers and hairs. Integument patterns are visible and experimentally manipulatable, helping us reveal pattern formative processes. Variability is seen in regional phenotypic specificities and temporal cycling at different physiological stages.
Here we show some cellular/molecular bases revealed by analyzing integument patterns. (1) Localized cellular activity (proliferation, rearrangement, apoptosis, differentiation) transforms prototypic organ primordia into specific shapes. Combinatorial positioning of different localized activity zones generates diverse and complex organ forms. (2) Competitive equilibrium between activators and inhibitors regulates stem cells through cyclic quiescence and activation.
Dynamic interactions between stem cells and their adjacent niche regulate regenerative behavior, modulated by multi-layers of macro-environmental factors (dermis, body hormone status, and external environment). Genomics studies may reveal how positional information of localized cellular activity is stored. In vivo skin imaging and lineage tracing unveils new insights into stem cell plasticity. Principles of self-assembly obtained from the integumentary organ model can be applied to help restore damaged patterns during regenerative wound healing and for tissue engineering to rebuild tissues. Developmental Dynamics 244:905-920, 2015. © 2015 Wiley Periodicals, Inc.
组织模式在发育和再生过程中如何形成是一个尚未完全理解的基本问题。体表组织常常在空间（周期性模式形成）和时间（循环更新）上形成重复单元，比如羽毛和毛发。体表模式是可见的且可通过实验进行操控，这有助于我们揭示模式形成过程。在不同生理阶段的区域表型特异性和时间循环中可以观察到变异性。
在此我们展示了通过分析体表模式所揭示的一些细胞/分子基础。（1）局部细胞活动（增殖、重排、凋亡、分化）将原型器官原基转变为特定形状。不同局部活动区域的组合定位产生了多样且复杂的器官形态。（2）激活剂和抑制剂之间的竞争平衡通过周期性静止和激活来调节干细胞。
干细胞与其相邻微环境之间的动态相互作用调节再生行为，这种调节受到多层宏观环境因素（真皮、身体激素状态和外部环境）的影响。基因组学研究可能会揭示局部细胞活动的位置信息是如何存储的。体内皮肤成像和谱系追踪为干细胞可塑性提供了新的见解。从体表器官模型中获得的自组装原理可应用于帮助在再生伤口愈合过程中恢复受损模式，以及用于组织工程来重建组织。《发育动力学》2015年第244卷，第905 - 920页。© 2015威利期刊公司。
