Adipose progenitor cell dynamics

脂肪祖细胞动力学

• 批准号: 9912148
• 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/9912148
• 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.

脂肪组织在控制能量平衡和系统性代谢中起着核心作用。脂肪细胞从组织居民祖细胞中发展，这些细胞会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的损害导致脂肪纤维化和胰岛素抵抗。相反，增强脂肪形成可改善脂肪营养不良和肥胖相关的糖尿病。然而，关于体内脂肪前体细胞的身份，活性和调节鲜为人知。为了以完全公正的方式鉴定脂肪祖细胞，我们从白色脂肪组织中对基质 - 血管分数进行了单细胞RNA测序。来自> 12,000个细胞/研究的基因表达数据的聚类分析确定了许多不同的细胞群体。这包括两种不同类型的推定脂肪生成前体细胞，我们根据其基因特征有条件地称为“早期脂肪祖细胞”和“授权的前脂肪细胞”。以二肽基肽-4（DPP4）的细胞表面表达为特征的“早期祖细胞”富含在Wnt和TGF信号通路中的基因表达。 “所铸造的前皮细胞”以细胞间粘附分子1（ICAM1）的细胞表面表达为特征，并以其选择性表达了许多脂肪谱系标记，包括PPAR在内。在计算机细胞轨迹分析中，早期DPP4+祖细胞会引起ICAM1+前脂肪细胞以及另一种“新颖”细胞类型。与此相一致，初步移植研究表明，DPP4+祖细胞在体内产生ICAM1+细胞以及成熟的脂肪细胞。我们的中心假设是DPP4+早期祖细胞会导致脂肪中的ICAM1+前脂肪细胞在脂肪生成条件下。我们还假设Wnt信号控制早期脂肪生物祖细胞的命运和增殖活性，并且这些细胞失去其脂肪生物活性，并在衰老过程中采用肌纤维细胞命运。我们将使用最先进的方法（包括细胞移植，遗传谱系跟踪和单细胞转录组分析）严格检查这些新概念和假设。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质分化测定法来检查WNT2/DPP4+和ICAM1+细胞之间的命运，增殖和分层关系。特定目标2研究了Wnt信号通路在体外和体内的WNT2/DPP4+早期祖细胞的维持和活性中的作用。总之，这些研究将定义WAT中脂肪祖细胞的层次结构，确定早期祖细胞对白人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。