Lipid homeostasis and mitochondrial fitness in LAM pathogenesis and therapy

LAM 发病机制和治疗中的脂质稳态和线粒体适应性

• 批准号: 10930187
• 负责人: Carmen Priolo
• 金额: $ 43.49万
• 依托单位: BRIGHAM AND WOMEN'S HOSPITAL
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-09-23 至 2024-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10930187
• 关键词: Acceleration; Acids; Actins; Amino Acids; Biochemical Pathway; Bioenergetics; Biological Assay; Biological Markers; Bypass; Carnitine Palmitoyltransferase I; Cells; Cellular Metabolic Process; Citric Acid Cycle; Clinical; Complex; Data; Development; Diffuse; Disease; Disease Progression; Dose; Enzymes; FDA approved; FRAP1 gene; Fatty Acids; Fatty acid glycerol esters; Feedback; Genetic; Glucose; Growth; Growth Factor; High Fat Diet; Homeostasis; Hyperactivity; Image; In Vitro; Lipids; Lung; Lung Lymphangioleiomyomatosis; Lymphangioleiomyomatosis; Mediator; Metabolic; Mitochondria; Mutation; Negative Finding; Nutrient; Oncogenic; Oxygen; Palmitates; Pathogenesis; Patients; Pharmaceutical Preparations; Phosphotransferases; Pleural effusion disorder; Positron-Emission Tomography; Pre-Clinical Model; Proliferating; Publishing; Radioisotopes; Regulation; Renal Angiomyolipoma; Role; Route; Sirolimus; Smooth Muscle; Stable Isotope Labeling; Supplementation; System; TSC1 gene; TSC1/2 gene; TSC2 gene; Testing; Therapeutic Intervention; Toxic effect; Tumor Suppressor Genes; Water; Woman; cell growth; experimental study; fatty acid oxidation; fitness; imaging biomarker; improved; in vivo; inhibitor; lipid metabolism; metabolic fitness; microPET; mitochondrial fitness; novel; novel therapeutics; oxidation; programs; pulmonary function; pulmonary function decline; pyruvate dehydrogenase; randomized trial; response; sensor; stable isotope; translational potential; tumorigenesis; tumorigenic; uncontrolled cell growth

Abstract Lymphangioleiomyomatosis (LAM) is a rare multisystem disease of women, characterized by progressive cystic lung destruction and diffuse proliferation of smooth muscle-like cells. LAM cells harbor inactivating mutations in the TSC1 or TSC2 tumor suppressor gene, which results in hyperactivation of mammalian target of rapamycin complex 1 (mTORC1). Rapamycin is an FDA-approved treatment for LAM; however, clinical response is heterogeneous across patients, and disease progression resumes once treatment is stopped. New therapies to improve the rate and durability of response remain a critical unmet need in LAM. Furthermore, the lack of imaging or other quantitative biomarkers of disease progression (beyond pulmonary function) limits clinical progress. mTORC1 promotes metabolic reprogramming and uncontrolled cell growth. We have identified a novel metabolic hallmark of LAM cells: a deregulation of the Randle cycle, a competitive interplay between fatty acids and glucose as substrates for mitochondrial oxidation, that promotes metabolic fitness and viability. Genetic inhibition of carnitine palmitoyltransferase 1A (CPT1A), the rate-limiting enzyme of fatty acid β-oxidation (FAO) suppressed in vivo tumorigenesis of TSC2-deficient cells by 50%, and inhibition of pyruvate dehydrogenase (PDH, a key mediator in the Randle cycle) and the tricarboxylic (TCA) cycle by a first-in-class mitochondrial inhibitor suppressed tumorigenesis by 90%, highlighting the translational potential of this project. Moreover, supplementation of exogenous fats stimulated the proliferation of LAM cells, in vitro and in vivo. Our central hypothesis is that PDH and CPT1 promote LAM cell fitness and proliferation via regulation of mitochondrial bioenergetics and lipid homeostasis. A key translational corollary of this hypothesis is that these biochemical pathways will provide opportunities for therapeutic interventions and the development of imaging biomarkers. Our central hypothesis will be tested in two Aims: Aim 1. To determine the metabolic derangements underlying lipid homeostasis and mitochondrial bioenergetics in TSC2-deficient cells. We will test the working hypotheses that LAM cells enhance mitochondrial efficiency by deregulating the Randle cycle and promoting utilization of exogenous fats, and that this metabolic asset supports LAM cell growth. Aim 2. To elucidate the PDH and CPT1A-dependent tumorigenic mechanisms in preclinical models of LAM in vivo. We will test the working hypothesis that PDH and lipid homeostasis are critical to LAM tumorigenesis. Our approaches will include stable isotope-labeled nutrients (glucose and palmitate) and deuterated water-based tracing experiments, and [18F]fluorothia-6-heptadecanoic acid (FTHA) micro-PET (positron emission tomography) imaging to probe LAM cell metabolism in vivo. The long-term objectives of this project are to harness the distinctive bioenergetic vulnerabilities of LAM cells to improve therapies and develop effective imaging strategies for women with LAM.

摘要 淋巴管平滑肌瘤病是一种罕见的多系统疾病， 囊性肺破坏和平滑肌样细胞弥漫性增殖。LAM细胞携带失活 TSC 1或TSC 2肿瘤抑制基因突变，导致哺乳动物靶细胞过度活化， 雷帕霉素复合物1（mTORC 1）。雷帕霉素是FDA批准的用于LAM的治疗;然而， 患者之间的反应是异质的，一旦停止治疗，疾病进展就会恢复。新 改善反应的速率和持久性的疗法仍然是LAM中未满足的关键需求。而且 缺乏疾病进展的成像或其他定量生物标志物（超出肺功能）限制 临床进展 mTORC 1促进代谢重编程和不受控制的细胞生长。我们发现了一本小说 LAM细胞的代谢标志：Randle循环的失调，脂肪酸之间的竞争性相互作用 和葡萄糖作为线粒体氧化的底物，其促进代谢适应性和生存能力。遗传 抑制脂肪酸β-氧化（FAO）的限速酶肉毒碱棕榈酰转移酶1A（CPT 1A） 抑制TSC 2缺陷细胞的体内肿瘤发生50%，并抑制丙酮酸脱氢酶 (PDH，Randle循环中的关键介质）和三羧酸（TCA）循环 抑制剂抑制了90%的肿瘤发生，突出了该项目的翻译潜力。此外，委员会认为， 外源性脂肪的补充刺激LAM细胞的增殖，在体外和体内。我们的中央 假设是PDH和CPT 1通过调节线粒体膜电位促进LAM细胞适应性和增殖， 生物能量学和脂质体内平衡。这一假设的一个关键的翻译推论是，这些生物化学物质 通路将为治疗干预和成像生物标志物的开发提供机会。 我们的中心假设将在两个目标中得到检验： 目标1.确定脂质稳态和线粒体代谢紊乱的基础， TSC 2缺陷细胞中的生物能量学。我们将测试LAM细胞增强 通过解除Randle循环的调节和促进外源脂肪的利用来提高线粒体效率， 这种代谢资产支持LAM细胞生长。 目标2.在临床前模型中阐明PDH和CPT 1A依赖的致瘤机制 体内的LAM。我们将检验PDH和脂质稳态对LAM至关重要的工作假设 肿瘤发生我们的方法将包括稳定的同位素标记的营养素（葡萄糖和棕榈酸）， 氘代水基示踪实验和[18F]氟硫代-6-十七烷酸（FTHA）微型PET （正电子发射断层扫描）成像以探测体内LAM细胞代谢。 该项目的长期目标是利用LAM独特的生物能量脆弱性 细胞，以改善治疗和开发有效的成像策略，为妇女与LAM。