Understanding Spinal Cord Regeneration; the role of dynamic gene expression

胚胎阶段的动物在破坏性损伤后能够重建功能组织。再生医学领域的广泛研究旨在了解胚胎发生和再生程序之间的相似性，尽管在过去的几十年里取得了巨大的进步，但许多方面的生物学和分子机制仍然未知。包括人类在内的哺乳动物在脊髓损伤（SCI）后不能替换丢失的神经元，而斑马鱼可以再生神经元来替换损伤后丢失的神经元。损伤后，神经干细胞在具有再生能力的物种中开始增殖并产生新的神经元，但在哺乳动物中，只产生有助于瘢痕形成的细胞。我自己的研究表明，在发育过程中，新神经元的产生（神经发生），基因并不是简单的开或关。相反，某些基因的水平受特定因素的影响，随着时间的推移而动态变化，并控制细胞是决定保持为增殖的神经干细胞还是成为新的神经元。众所周知，相同的基因在脊髓再生（SCR）过程中很重要，但它们是如何工作的尚不清楚。因此，尚不清楚在SCR期间和新神经元的产生是否也受到基因活性脉冲的控制。阐明在具有再生能力的动物中导致SCR成功的动态信号和机制将产生重要和有价值的结果，可以在高等生物中进行测试。斑马鱼是一种功能强大、易于控制和健壮的动物模型，能够在脊髓损伤后实现功能性神经再生，其特点是神经新生和神经元连接再生。在这个提议中，我将使用斑马鱼幼虫作为实验模型，利用它的再生能力和对基因操作的适应性。我将使用最先进的实时成像技术实时显示基因活动。我将介绍遗传变化，以评估神经干细胞在SCR期间进行神经元决策时脉动基因活动的功能重要性。我将研究脉冲基因活动的变化如何影响基因景观，并在SCR期间改变细胞命运的决定。解决SCR中细胞命运决定过程中脉动基因活性的功能重要性，将为无再生能力动物（如小鼠和人类）的SCI提供潜在的翻译意义。

Animals at embryonic stages are capable of reconstructing functional tissue after disruptive injuries. Extensive research in the field of regenerative medicine aims to understand the similarities between embryogenesis and regeneration programs and despite great advances in the last few decades, many aspects of the biological and molecular mechanisms remain unknown. Mammals, including humans, cannot replace lost neurons after spinal cord injury (SCI), whereas zebrafish can regenerate neurons to replace those that are lost after injury. Upon injury, neural stem cells initiate proliferation and generate new neurons in species with regenerative capacity, but in mammals, only cells that contribute to scar formation are generated. My own research has shown that during development the generation of new neurons (neurogenesis), genes are not simply on or off. Instead, the levels of some genes pulse dynamically over time, influenced by specific factors, and control whether the cells decide to stay as proliferating neural stem cell or become new neurons. It is known that the same genes are important during spinal cord regeneration (SCR) but how they work isn't known. Therefore, it is not clear whether during SCR and the generation of new neurons are also controlled by the pulses in gene activity. Elucidating the dynamic signals and mechanisms leading to successful SCR in an animal with regenerative capacity will generate important and valuable outcomes that can be tested in higher organisms. Zebrafish is a powerful, tractable and robust animal model able to achieve functional neural regeneration following SCI, characterised by de novo neurogenesis and regrowth of neuronal connections. In this proposal I will be using larvae zebrafish as an experimental model, taking advantage of its regenerative capacity and its amenability to genetic manipulation. I will use state-of-the art live imaging techniques that show gene activity in real time. I will introduce genetic changes to assess the functional importance of pulsatile gene activity when neural stem cells undertake neuronal decisions during SCR. I will investigate how changes on pulsatile gene activity can affect the genetic landscape and alter cell-fate decisions over time during SCR. Addressing the functional importance of pulsatile gene activity during cell-fate decisions in SCR, will provide insights with potential translational implications for SCI in animals with no regenerative capacity, such as mice and humans.