Understanding the molecular pathways that underpin production, sensing and protection against aldehydes

短链醛（最重要的是甲醛）是一种在生产中经常使用的高活性分子，也是生物实验室中常见的固定剂。令人担忧的是，这些因子也是内源性产生的，包括代谢途径（如酒精代谢）和细胞分化事件的副产物。甲醛是DNA损伤的有力来源，大多数人认为它是一种DNA交联剂，会扭曲DNA的结构，阻止DNA的分离。这会导致突变断裂，阻止我们DNA的准确读取和复制。幸运的是，细胞拥有“双层”保护机制，限制了这些分子的破坏性影响。第一层代表积极解毒甲醛的代谢酶。第二种是由DNA损伤修复蛋白组成的，在损伤发生后修复损伤。虽然这种冗余意味着单个突变的个体可以保持保护，但多种酶的突变可能导致：贫血、早衰（加速衰老）、骨髓衰竭、神经变性、癌症、发育异常、肝肾衰竭和严重的体重减轻。在缺乏两层保护的情况下，甲醛的整体生理后果已经得到了大量研究，但我们对甲醛破坏的特定细胞过程仍然知之甚少，也不知道它的起源。该项目将研究细胞如何对甲醛作出反应以及甲醛在哪里产生的基本问题。目前有两种证据可以用来解决这个问题。首先，存在对甲醛胁迫敏感的特定途径，这些途径向转录网络发出信号并驱动基因表达的变化。其次，在不同的转录状态下有局部甲醛产生的迹象。这个项目将扩展这两种现象，以建立一个关于甲醛在细胞中的来源和反应的图片。我将采用先进的基因编辑和测序技术进行CRISPR敲除筛选，目的是确定对甲醛敏感的途径，以及潜在的新的一级保护酶。该结果的下游验证将首先在体外系统中进行，然后进入体内小鼠模型的生成，以确定其生理重要性。其次，我将使用先进的显微镜和化学探针工具来定位细胞中甲醛分解代谢的特定位点。通过了解使细胞对甲醛敏感的分子途径和位点，我们可以更广泛地了解甲醛诱发疾病的机制。扩大对驱动甲醛应激的已知遗传因素的了解，是预防和早期发现相关疾病的重要组成部分，也是为精准医学开辟道路的重要组成部分。

Short chain aldehydes (most importantly formaldehyde) are highly reactive molecules used routinely in manufacturing, and are commonplace as fixative agents in biological laboratories. Worryingly, these factors are also produced endogenously, including as by-products of metabolic pathways (e.g., alcohol metabolism) and cell differentiation events. Formaldehyde is a potent source of DNA damage, most understood as a DNA cross-linking agent, distorting the structure and preventing the separation of DNA. This leads to mutagenic breaks, prevents accurate reading and replication of our DNA. Fortunately, cells possess a "two-tiered" protection mechanism that limits the damaging effects of these molecules. The first tier represents metabolic enzymes that actively detoxify formaldehyde. The second is made up of DNA damage repair proteins that fix the damage after it has happened. While this redundancy means individuals with a single mutation can remain protected, mutations in multiple enzymes can result in: anaemia, progeria (accelerated ageing), bone marrow failure, neurodegeneration, cancer, developmental abnormalities, liver and kidney failure, and severe weight loss. Where the overall physiological consequences of formaldehyde in the absence of two-tier protection have been heavily studied, we still know very little about the specific cellular process formaldehyde disrupts, nor of its origins. This project will look into the fundamental questions of how does the cell respond to formaldehyde and where is it produced? There are two current lines of evidence we can use to access this problem. Firstly, there are specific pathways sensitive to formaldehyde stress that are signalled to the transcriptional network and drive changes in gene expression. Secondly, there are signs of localised formaldehyde production in different transcriptional states. This project will expand on both of these phenomena to build a picture of the sources of and responses to formaldehyde in cells. I will employ advanced gene editing and sequencing technologies to perform a CRISPR knock out screen, with the aim of identifying pathways sensitive to formaldehyde, and potentially new tier 1 protection enzymes. Downstream validation of the results of this will be performed first in in vitro systems, progressing into the generation of in vivo mouse models to determine their physiological importance. Secondly, I will use advanced microscopy and chemical probe tools to localise specific sites of formaldehyde catabolism in cells. By understanding the molecular pathways and sites that render cells sensitive to formaldehyde, we can more broadly understand the mechanisms that underline formaldehyde induced morbidities. Expanding this knowledge of known genetic factors that drive formaldehyde stress, is an essential part in prevention and early detection of associated diseases, as well as opening avenues for precision medicine.