In vivo imaging of adipose growth dynamics in zebrafish

斑马鱼脂肪生长动态的体内成像

• 批准号: BB/X009467/1
• 负责人: James Minchin
• 金额: $ 67.58万
• 依托单位: University of Edinburgh
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2023
• 资助国家: 英国
• 起止时间: 2023 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=BB%2FX009467%2F1
• 关键词: vivo; imaging; adipose; growth; dynamics

Fat tissue is highly dynamic and can expand and contract throughout life. Fat tissue can expand via two distinct mechanisms: (i) by the addition of new fat cells (hyperplastic growth) and (ii) by the growth in size of existing fat cells (hypertrophic growth). The mechanism by which fat tissue expands exerts a strong influence on cardiometabolic disease risk. For example, excessive hypertrophic growth which results in adipose characterised by few, but very large fat cells (so called 'hypertrophic morphology') is associated with insulin resistance, diabetes and cardiovascular disease. Whereas, hyperplastic growth characterised by many, small fat cells (so called 'hyperplastic morphology') is associated with improved metabolic parameters. Therefore, understanding how hyperplastic and hypertrophic growth are regulated and coordinated to pattern adipose morphology is of central biomedical importance. Surprisingly, owing to current methodological constraints, real-time in vivo imaging of adipose growth and remodelling has not been extensively attempted at a cellular-level resolution. For such a dynamic tissue, this lack of in vivo imaging has resulted in large knowledge gaps pertaining to dynamic cellular processes that underpin adipose growth. To fill these knowledge gaps, we have developed a new in vivo imaging model in zebrafish that allows us to visualise fat cells and their precursors non-invasively in living animals and in real-time. These new transgenic tools and methodologies allow us an unprecedented view of the dynamic nature of fat tissue growth. The overall goal of this proposal is to leverage our new zebrafish in vivo imaging model to understand how hyperplastic and hypertrophic growth mechanisms are coordinated, and how they contribute to cardiometabolic disease risk. Our preliminary studies have identified that zebrafish fat tissue undergoes phasic growth characterised by 'waves' of hyperplastic growth, coupled with transient fat cell shrinkage and expansive hypertrophic growth. In Aim 1 of this project, we will conduct studies to understand the molecular and genetic regulation of phasic hyperplastic adipose growth in zebrafish. In Aim 2, we will conduct experiments to understand how fluctuations in fat cell size are regulated and help pattern adipose. Finally, in Aim 3, we will combine human and zebrafish data to identify new candidate genes which we think regulate hyperplastic/hypertrophic growth. Then, we will perform large-scale mutagenesis in zebrafish to functionally evaluate these candidate growth genes. Altogether, this proposal will leverage new and exciting imaging methodologies to provide foundational new insights into the dynamic cellular processes that pattern adipose tissue.

脂肪组织是高度动态的，可以在整个生命过程中扩张和收缩。脂肪组织可以通过两种不同的机制扩张：（i）通过添加新的脂肪细胞（增生性生长）和（ii）通过现有脂肪细胞的大小增长（肥大性生长）。脂肪组织扩张的机制对心脏代谢疾病的风险有很大的影响。例如，过度的肥大性生长导致以很少但非常大的脂肪细胞为特征的脂肪（所谓的“肥大形态”）与胰岛素抵抗、糖尿病和心血管疾病相关。然而，以许多小脂肪细胞为特征的增生性生长（所谓的“增生形态学”）与改善的代谢参数相关。因此，了解如何调节和协调增生性和肥大性生长模式脂肪形态是生物医学的重要性。令人惊讶的是，由于目前的方法的限制，实时在体内成像的脂肪生长和重塑还没有广泛尝试在细胞水平的分辨率。对于这样的动态组织，体内成像的这种缺乏导致了与支撑脂肪生长的动态细胞过程有关的大的知识缺口。为了填补这些知识空白，我们在斑马鱼中开发了一种新的体内成像模型，使我们能够在活体动物中实时非侵入性地可视化脂肪细胞及其前体。这些新的转基因工具和方法使我们对脂肪组织生长的动态性质有了前所未有的认识。该提案的总体目标是利用我们新的斑马鱼体内成像模型来了解增生和肥大生长机制如何协调，以及它们如何导致心脏代谢疾病风险。我们的初步研究已经确定，斑马鱼脂肪组织经历阶段性生长，其特征在于增生性生长的“波”，再加上短暂的脂肪细胞收缩和膨胀性肥大生长。在本项目的目标1中，我们将进行研究，以了解斑马鱼阶段性增生脂肪生长的分子和遗传调控。在目标2中，我们将进行实验，以了解脂肪细胞大小的波动是如何调节的，并有助于脂肪的形成。最后，在目标3中，我们将结合联合收割机人类和斑马鱼的数据，以确定我们认为调节增生/肥大生长的新的候选基因。然后，我们将在斑马鱼中进行大规模的诱变，以功能评估这些候选生长基因。总之，这项提案将利用新的和令人兴奋的成像方法，提供基本的新见解的动态细胞过程，模式脂肪组织。