The regenerative response to tissue necrosis

项目总结 细胞死亡在创伤、疾病或感染后的伤口愈合和再生中起着关键作用。细胞凋亡 在损伤部位可以显著影响周围细胞的行为，因为死亡细胞产生的信号 可以引发炎症、增殖并决定其邻居的生存。因此，这些活动可以 直接调节组织从损伤中恢复的能力。例如，在小鼠肝损伤后，发出信号 濒临死亡的肝细胞产生的分子推动再生增殖。因此，更好地理解如何 组织对损伤做出反应-信号可以发现新的治疗干预措施，以促进伤口愈合 和再生。尽管在理解细胞凋亡如何促进细胞死亡方面取得了进展 再生，关于非凋亡性形式的细胞死亡，如坏死，是否会有 相似的角色。坏死发生在许多人类疾病中，特别是在缺血性损伤(中风和 心脏病)、感染和癌症。坏死性细胞死亡后的再生明显比 这是由细胞凋亡诱导的，但已在各种组织中被证明，这表明迄今尚未确定和 每种情况下都可能存在不同的机制。因此，这项工作的目的是描述基本的 导致坏死后再生的遗传机制而不是细胞凋亡。 来自凋亡细胞的信号影响周围组织的证据最初来自对幼虫的研究 果蝇的翅膀原基，是研究再生的一个有吸引力和强大的模型。可用的遗传工具 导致了对再生所必需的遗传事件的重要洞察。的研究 幼虫翅膀的再生通常依赖于基因消融，这是一种有效和强大的方法，可以 在空间和时间上控制在组织中诱导的细胞死亡。然而，尽管它有优势，但这 方法在可实现的遗传操作方面也受到限制，并且缺乏研究非 细胞凋亡性形式的组织丢失，如坏死。为了克服这些问题，我们建立了一个新的 方法，双重对照，允许我们在发育中的翅膀原基诱导坏死或凋亡， 刺激对任何一种损伤的再生反应。我们的初步调查表明，坏死和 细胞凋亡导致周围组织中基因表达和形态的显著不同。 然而，重要的是，再生在这两种情况下都会发生。作为对以前方法的改进，这部小说 该系统还允许我们专门针对周围再生组织进行基因操作， 与消融无关。因此，这些实验可以利用专门构建的大型RNAi 筛选果蝇中可用的文库，直接询问再生细胞。我们建议使用这一新的 表征导致坏死后成功再生的损伤的遗传反应的方法 与细胞凋亡相比，以期在每种情况下确定再生能力的新调节因素。

PROJECT SUMMARY Cell death has a critical role in wound healing and regeneration following injury, disease or infection. Apoptosis at a site of injury can significantly impact the behavior of surrounding cells, as signals produced by dying cells can induce inflammation, proliferation and dictate the survival of their neighbors. These activities can therefore directly regulate a tissue’s ability to recover from damage. For example, following liver injury in mice, signaling molecules produced by dying hepatocytes drive regenerative proliferation. Thus, a better understanding of how a tissue responds to damage-signals could uncover novel therapeutic interventions to improve wound healing and regeneration. Although advances have been made in understanding how apoptosis contributes to regeneration, little is known about whether non-apoptotic forms of cell death, such as necrosis, might have a similar role. Necrosis occurs in numerous human diseases, particularly following ischemic injury (stroke and heart attack), infections and cancer. Regeneration following necrotic cell death is significantly more variable than that induced by apoptosis, but has been documented in various tissues, suggesting that as yet unidentified and distinct mechanisms might exist in each context. Thus, the aim of this work is to characterize the fundamental genetic mechanisms that lead to regeneration following necrosis versus apoptosis. Evidence that signals from apoptotic cells impact surrounding tissues first originated from studies of the larval wing primordia in Drosophila, an attractive and powerful model to study regeneration. The genetic tools available in Drosophila have led to important insights into the genetic events necessary for regeneration. Studies of regeneration in the larval wing commonly rely on genetic ablation, an efficient and robust approach that permits spatially and temporally controlled cell death to be induced in tissues. However, despite its advantages, this method is also limited in the genetic manipulations that can be achieved, and is lacking the ability to study non- apoptotic forms of tissue loss, such as necrosis. To overcome these problems we have established a new method, DUAL Control, that allows us to induce necrosis or apoptosis in the developing wing primordia, stimulating a regenerative response to either type of damage. Our initial investigations suggest that necrosis and apoptosis lead to dramatically different gene expression changes and morphologies in the surrounding tissue. Importantly, however, regeneration occurs in both situations. As an advance on previous approaches, this novel system also allows us to target genetic manipulations specifically to the surrounding regenerating tissue, independent of ablation. These experiments can therefore take advantage of the large purpose-built RNAi screening libraries available in Drosophila to interrogate regenerating cells directly. We propose to use this new method to characterize the genetic response to damage that leads to successful regeneration following necrosis compared to apoptosis, with a view to identifying novel regulators of regenerative capacity in each context.