Elucidating the Mechanisms of Lymphatic Muscle Cell Dysfunction in Aging and Inflammation

项目摘要/摘要。 淋巴功能障碍已知与各种疾病有关，包括衰老和 炎症，如阿尔茨海默病、心血管功能下降和关节炎进展。贯穿始终 随着年龄的增长，淋巴管的收缩能力恶化，这与必需的基因表达减少有关 淋巴肌肉细胞(LMC)中调节动态平衡收缩和细胞骨架完整性的途径。 同样，我们之前发现淋巴功能障碍的年龄相关细胞机制 肿瘤坏死因子转基因小鼠慢性炎症性关节炎模型与 老年人关节疾病的进展和关节引流淋巴管收缩的丧失 老鼠。在这些老年小鼠中，PLV在超微结构水平上显示出显著的LMC萎缩，这是 建议推动淋巴功能的消除，并加剧疾病的进展。作为临床医生 相关研究发现，活动期类风湿性关节炎患者的左心室功能较少， 手部表面的淋巴清除减少。因此，我们假设炎症在 炎症的LMC将表现出类似的功能障碍的年龄相关的损伤加速 LMC收缩和细胞骨架完整性所必需的基因通路。为了检验这一假设，我们建议 评估α-平滑肌肌动蛋白(PLVSMMA)+α-LMC的覆盖率并研究转录变化 对青年(2月龄)、老年人(8月龄)和老年人(24月龄)进行了单细胞RNA测序(ScRNAseq)。 WT和肿瘤坏死因子-Tg组小鼠。为了实现这一目标，我们已经证明了αSMA+PLV-LMC的覆盖范围是 老年(8个月大)的肿瘤坏死因子-甘油三酯小鼠相对于WT仔鼠减少。此外，我们还取得了初步的成果 在老年LMC的scRNAseq中的成功表明了这种方法的可行性。鉴于这些不足之处 有针对性地研究其在健康和疾病中的作用所需的LMC的特征，我们的scRNAseq 数据还提供了LMCs是转录上不同的血管肌肉细胞的证据。通过 完成这项拨款建议所体现的研究目标，我们有机会提供 为未来的临床前研究和LMCs的靶向治疗干预提供了相当大的创新。排队 根据申请者的研究培训计划，PI将获得宝贵的经验，主要是在板凳研究 有更多机会培养临床试验设计、医疗保健、学术领导力和 罗切斯特大学的社区推广活动有着培养成功医生的宝贵历史- 科学家。对于接下来的PA-21-049 F30拨款申请，我们建议阐明LMC的机制 衰老和炎症过程中的功能障碍对淋巴细胞生物学和我们的 对神秘的年龄相关关节炎进展的理解。

Project Summary/Abstract. Lymphatic dysfunction is known to be associated with various disorders involved in both aging and inflammation, such as Alzheimer’s disease, cardiovascular decline, and arthritic progression. Throughout aging, lymphatic contractility has been shown to deteriorate related to reduced gene expression of essential pathways that mediate homeostatic contractions and cytoskeletal integrity in lymphatic muscle cells (LMCs). Similarly, we previously discovered that age-dependent cellular mechanisms of lymphatic dysfunction in the tumor necrosis factor transgenic (TNF-Tg) mouse model of chronic inflammatory arthritis are associated with progression of joint disease and the loss of joint-draining popliteal lymphatic vessel (PLV) contractions in aged mice. In these aged mice, the PLV demonstrates significant LMC atrophy at an ultrastructural level, which is proposed to drive the elimination of lymphatic function and exacerbate disease progression. As a clinical correlate, we have found that patients with active rheumatoid arthritis have fewer functional LVs and diminished lymphatic clearance on the surface of the hands. Thus, we hypothesize that inflammation mediates accelerated age-related damage to LMCs where inflamed LMCs will exhibit a comparable dysfunction in the gene pathways necessary for LMC contractility and cytoskeletal integrity. To test this hypothesis, we propose to assess alpha smooth muscle actin (αSMA)+ PLV-LMC coverage and investigate transcriptional changes by single cell RNA sequencing (scRNAseq) in young (2-month-old), aged (8-month-old), and elderly (24-month- old) WT and TNF-Tg mice. Towards this goal, we have demonstrated that αSMA+ PLV-LMC coverage is reduced in aged (8-month-old) TNF-Tg mice relative to WT littermates. Additionally, we achieved preliminary success in scRNAseq of aged LMCs to indicate the feasibility of this approach. Given the inadequate characterization of LMCs necessary for targeted research into their role in health and disease, our scRNAseq data also provides evidence that LMCs are transcriptionally distinct vascular muscle cells. Through the completion of the research aims embodied in this grant proposal, we have the opportunity to provide considerable innovation for future pre-clinical research and targeted therapeutic interventions of LMCs. In line with the applicant’s Research Training Plan, the PI will gain valuable experience primarily in bench research with additional opportunities to foster abilities in clinical trial design, medical care, academic leadership, and community outreach at the University of Rochester with a cherished history of producing successful physician- scientists. For the following PA-21-049 F30 grant submission, we propose to elucidate the mechanisms of LMC dysfunction during both aging and inflammation for the benefit of lymphatic cellular biology and our understanding of the enigmatic age-related progression of arthritis.