Adipose progenitor cell dynamics

脂肪祖细胞动力学

• 批准号: 10087926
• 负责人: Patrick Seale
• 金额: $ 54.82万
• 依托单位: UNIVERSITY OF PENNSYLVANIA
• 依托单位国家: 美国
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-04-09 至 2023-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10087926
• 关键词: Adipocytes; Adipose tissue; Adopted; Adult; Affect; Aging; Biological Assay; Blood Vessels; Cell Differentiation process; Cell Transplantation; Cell surface; Cells; Cluster Analysis; Data; Development; Diabetes Mellitus; Dipeptidyl Peptidases; Down-Regulation; Fibrosis; Gene Expression; Gene Expression Profiling; Genetic; Genetic Diseases; High Fat Diet; Human; Impairment; In Vitro; Insulin Resistance; Intercellular adhesion molecule 1; Knowledge; Lead; Lipodystrophy; Maintenance; Mesenchymal Differentiation; Metabolic Diseases; Metabolism; Methods; Mus; Myofibroblast; Newborn Infant; Obesity; Play; Population; Process; RNA; Regulation; Role; Signal Pathway; Signal Transduction; Stimulus; Testing; Tissue Differentiation; Tissues; Transplantation; WNT Signaling Pathway; Work; adipocyte differentiation; age effect; aged; base; cell type; energy balance; genetic signature; improved; in silico; in vivo; insulin sensitivity; lipid biosynthesis; loss of function; novel; novel therapeutics; precursor cell; progenitor; recruit; response; selective expression; single-cell RNA sequencing; stem cells; transcriptomics

Adipose tissue plays a central role in regulating energy balance and systemic metabolism. Adipocytes develop from tissue-resident progenitor cells that differentiate in response to environmental stimuli. Impairments in adipocyte differentiation, caused by genetic disease, aging or obesity, lead to adipose fibrosis and insulin resistance. Conversely, enhancing adipogenesis ameliorates lipodystrophy- and obesity-related diabetes. However, there is relatively little known about the identity, activity and regulation of adipose precursor cells in vivo. To identify adipose progenitor cells in a completely unbiased manner, we performed single cell RNA-sequencing of the stromal-vascular fraction from white adipose tissue. Clustering analysis of the gene expression data from >12, 000 cells/study identified many distinct cell populations. This included two distinct types of putative adipogenic precursor cells, which we conditionally called “early adipose progenitors” and “committed preadipocytes” based on their gene signatures. “Early progenitors”, marked by cell surface expression of Dipeptidyl peptidase-4 (DPP4), are enriched for expression of genes in the Wnt and Tgf signaling pathways. “Committed preadipocytes” are marked by cell surface expression of Intercellular adhesion molecule-1 (ICAM1) and were noted for their selective expression of many adipose lineage markers, including Ppar. In silico cell trajectory analysis predicts that early DPP4+ progenitors give rise to ICAM1+ preadipocytes as well as another “novel” cell type. Consistent with this, preliminary transplantation studies show that DPP4+ progenitor cells produce ICAM1+ cells as well as mature adipocytes in vivo. Our central hypothesis is that DPP4+ early progenitor cells give rise to adipose-lineage committed ICAM1+ preadipocytes under adipogenic conditions. We additionally hypothesize that Wnt signaling controls the fate and proliferative activity of early adipogenic progenitors and that these cells lose their adipogenic activity and adopt a myofibroblast fate during the aging process. We will rigorously examine these new concepts and hypotheses using state-of-the-art approaches, including cell transplantation, genetic lineage tracing, and single cell transcriptomic analyses. Specific Aim 1 uses mesenchymal differentiation assays in culture, cell transplantation and genetic lineage tracing analysis to examine the fate, proliferation and hierarchical relationship between Wnt2/DPP4+ and ICAM1+ cells. Specific Aim 2 investigates the role of the Wnt signaling pathway in regulating the maintenance and activity of Wnt2/DPP4+ early progenitors in vitro and in vivo. Together, these studies will define the hierarchy of adipose progenitor cells in WAT, determine the contribution of early progenitors to white and beige adipocyte development and assess the effects of aging on adipose progenitor function.

脂肪组织在调节能量平衡和全身代谢中发挥着核心作用。脂肪细胞由组织驻留祖细胞发育而来，这些祖细胞响应环境刺激而分化。由遗传疾病、衰老或肥胖引起的脂肪细胞分化受损，会导致脂肪纤维化和胰岛素抵抗。相反，增强脂肪生成可改善脂肪营养不良和肥胖相关的糖尿病。然而，人们对体内脂肪前体细胞的身份、活性和调节知之甚少。为了以完全公正的方式鉴定脂肪祖细胞，我们对白色脂肪组织的基质血管部分进行了单细胞 RNA 测序。对来自 >12, 000 个细胞/研究的基因表达数据进行聚类分析，识别出许多不同的细胞群。这包括两种不同类型的假定的脂肪形成前体细胞，我们根据其基因特征有条件地将其称为“早期脂肪祖细胞”和“定型前脂肪细胞”。以细胞表面二肽基肽酶 4 (DPP4) 表达为标志的“早期祖细胞”在 Wnt 和 Tgf 信号通路中的基因表达富集。 “定型前脂肪细胞”以细胞表面细胞间粘附分子 1 (ICAM1) 的表达为标志，并因其选择性表达许多脂肪谱系标志物（包括 Ppar）而闻名。计算机细胞轨迹分析预测早期 DPP4+ 祖细胞会产生 ICAM1+ 前脂肪细胞以及另一种“新”细胞类型。与此一致的是，初步移植研究表明 DPP4+ 祖细胞在体内产生 ICAM1+ 细胞以及成熟脂肪细胞。我们的中心假设是 DPP4+ 早期祖细胞在脂肪形成条件下产生脂肪谱系定型 ICAM1+ 前脂肪细胞。我们还假设 Wnt 信号传导控制早期脂肪形成祖细胞的命运和增殖活性，并且这些细胞在衰老过程中失去其脂肪形成活性并采用肌成纤维细胞命运。我们将使用最先进的方法严格检验这些新概念和假设，包括细胞移植、遗传谱系追踪和单细胞转录组分析。具体目标 1 在培养、细胞移植和遗传谱系追踪分析中使用间充质分化测定来检查 Wnt2/DPP4+ 和 ICAM1+ 细胞之间的命运、增殖和层次关系。具体目标 2 研究 Wnt 信号通路在体外和体内调节 Wnt2/DPP4+ 早期祖细胞的维持和活性中的作用。这些研究将共同​​定义 WAT 中脂肪祖细胞的层次结构，确定早期祖细胞对白色和米色脂肪细胞发育的贡献，并评估衰老对脂肪祖细胞功能的影响。