Astrocytes represent a diverse and morphologically complex group of glial cells critical for shaping and maintaining nervous system homeostasis, as well as responding to injuries. Understanding the origins of astroglial heterogeneity, originated from a limited number of progenitors, has been the focus of many studies. Most of these investigations have centered on protoplasmic and pial astrocytes, while the clonal relationship of fibrous astrocytes or juxtavascular astrocytes has remained relatively unexplored. In this study, we sought to elucidate the morphological diversity and clonal distribution of astrocytes across adult cortical layers, with particular emphasis on their ontogenetic origins. Using the StarTrack lineage tracing tool, we explored the characteristics of adult astroglial clones derived from single and specific progenitors at various embryonic stages. Our results revealed a heterogeneous spatial distribution of astroglial clones, characterized by variations in location, clonal size, and rostro–caudal dispersion. While a considerable proportion of clones were confined within specific cortical layers, others displayed sibling cells crossing layer boundaries. Notably, we observed a correlation between clone location and developmental stage at earlier embryonic stages, although this relationship diminished in later stages. Fibrous astrocyte clones were exclusively confined to the corpus callosum. In contrast, protoplasmic or juxtavascular clones were located in either the upper or lower cortical layers, with certain clones displayed sibling cells distributed across both regions. Our findings underscore the developmental origins and spatial distribution of astroglial clones within cortical layers, providing new insights into the interplay between their morphology, clonal sizes, and progenitor heterogeneity.

中文翻译：

---

星形胶质细胞克隆的空间组织：发育祖细胞计时的作用

星形胶质细胞代表了一组多样化且形态复杂的神经胶质细胞，对于塑造和维持神经系统稳态以及对损伤做出反应至关重要。了解源自有限数量的祖细胞的星形胶质细胞异质性的起源一直是许多研究的焦点。大多数这些研究都集中在原生质和软脑膜星形胶质细胞上，而纤维性星形胶质细胞或血管旁星形胶质细胞的克隆关系仍然相对未经探索。在这项研究中，我们试图阐明星形胶质细胞在成人皮质层的形态多样性和克隆分布，特别强调它们的个体发生起源。使用 StarTrack 谱系追踪工具，我们探索了源自各个胚胎阶段的单个和特定祖细胞的成年星形胶质细胞克隆的特征。我们的结果揭示了星形胶质细胞克隆的异质空间分布，其特征在于位置、克隆大小和头尾分布的变化。虽然相当一部分克隆被限制在特定的皮质层内，但其他克隆则显示出跨越层边界的兄弟细胞。值得注意的是，我们在早期胚胎阶段观察到克隆位置和发育阶段之间的相关性，尽管这种关系在后期阶段减弱。纤维星形胶质细胞克隆仅局限于胼胝体。相反，原生质或近血管克隆位于上皮层或下皮层，某些克隆显示分布在两个区域的兄弟细胞。我们的研究结果强调了皮质层内星形胶质细胞克隆的发育起源和空间分布，为它们的形态、克隆大小和祖细胞异质性之间的相互作用提供了新的见解。