Metabolic Symbiosis: Lactate as an Epigenetic Regulator and a Biofuel in Age-dependent Intervertebral Disc Degeneration

代谢共生：乳酸作为年龄依赖性椎间盘退变的表观遗传调节剂和生物燃料

• 批准号: 10704160
• 负责人: Gwendolyn A Sowa
• 金额: $ 40.8万
• 依托单位: UNIVERSITY OF PITTSBURGH AT PITTSBURGH
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-09-15 至 2027-07-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10704160
• 关键词: Acetylation; Aerobic; Age; Back Pain; Bioenergetics; Bioinformatics; Biological Assay; Carbon; Cell Culture Techniques; Cell Separation; Cell Survival; Cell physiology; Cells; Chemicals; Chromatin; Chromatin Structure; DNA; Data; Degenerative Disorder; Development; Diffusion; Disease; Economic Burden; Environment; Enzyme Inhibitor Drugs; Enzymes; Epigenetic Process; Female; Foundations; Future; Gene Expression; Gene Expression Regulation; Genes; Genetic; Glucose; Glycolysis; Histones; Homeostasis; Human; Hypoxia; Injections; Interruption; Intervertebral disc structure; Knock-out; Lactic acid; Link; Low Back Pain; Lysine; Macrophage; Measures; Metabolic; Metabolism; Modeling; Molecular; Mus; Nutrient; Organ; Oxidative Phosphorylation; Oxygen; Pathway interactions; Pattern; Peripheral; Phenotype; Post-Translational Protein Processing; Public Health; Rattus; Reporting; Research; Role; Source; Spinal Diseases; Symbiosis; Tamoxifen; Testing; Tissues; Transcriptional Regulation; Transgenic Mice; Vertebral column; Waste Products; age related; anaerobic glycolysis; chromatin immunoprecipitation; chronic back pain; cost; deep sequencing; disability; extracellular; innovation; intervertebral disk degeneration; male; mouse model; new therapeutic target; novel; nucleus pulposus; nutrition; prevent; regenerative; socioeconomics; success; therapeutic target; tissue culture; transcriptome sequencing; uptake; wasting

Project Summary Intervertebral disc degeneration (IDD) underlies many spinal disorders and results in debilitating back pain, disability, and tremendous socioeconomic burden. The intervertebral disc (IVD) is the largest avascular organ comprised of a hypoxic nucleus pulposus (NP) center surrounded by an outer, more oxygenated annulus fibrosus (AF). The IVD contains copious amounts of lactic acid, which has long been viewed as a harmful waste byproduct of anaerobic glycolysis in the NP. However, we recently made two major advances that challenge this longstanding dogma. We demonstrated that AF cells can take up and utilize lactate as a carbon source via oxidative phosphorylation (OXPHOS), thus unveiling lactate-dependent metabolic symbiosis between NP and AF whereby the hypoxic NP cells make lactate to be used by the more aerobic AF cells as a carbon biofuel via OXPHOS. We also discovered high levels of IVD histone lactylation, a newly characterized type of histone post-translational modification (PTM) that uses lactate as a substrate precursor. Histone PTMs are critical to the dynamic modulation of chromatin structure and gene expression, and dysregulation of histone PTMs is closely linked with the development of many diseases. Based on our preliminary data, we hypothesize that disc lactate is not as a waste byproduct but rather serves as an important biofuel for the nutrient-poor disc and as a vital metabolic regulator of disc gene expression programming via histone lactylation. We propose three specific aims to test this hypothesis: (1) Determine whether lactate functions as an important metabolic regulator of disc gene expression through histone lactylation using rat disc cell culture models treated with chemical inhibitors of enzymes responsible for histone lactylation; (2) Determine whether disc histone lactylation and lactate- dependent metabolic symbiosis malfunction with age contributing to age-related IDD using young and old Fischer 344 rats; and (3) Determine whether interrupted disc lactate-dependent metabolic symbiosis disrupts disc histone lactylation pattern and promotes IDD using transgenic mouse models with AF-targeted genetic depletion to disrupt AF lactate uptake. Completion of the proposed studies will establish whether histone lactylation exerts epigenetic transcription regulation that controls disc matrix homeostasis and lactate-dependent metabolic symbiosis. Demonstrating the influences of lactate metabolism on age-related IDD through the mechanisms of epigenetic gene regulation and lactate-dependent metabolic symbiosis will be both novel and significant to identify new therapeutic targets to treat IDD with greater likelihood of success in the nutrient poor environment. This will be an innovative approach and significant advance over prior regenerative efforts which have had limited success in this unique tissue.

项目概要 椎间盘退变 (IDD) 是许多脊柱疾病的根源，并导致衰弱 背痛、残疾和巨大的社会经济负担。椎间盘（IVD）是 最大的无血管器官，由缺氧的髓核 (NP) 中心组成，周围环绕着 外部，含氧较多的纤维环（AF）。 IVD 含有大量乳酸， 长期以来，它一直被视为 NP 中无氧糖酵解的有害废物副产品。 然而，我们最近取得了两项重大进展，挑战了这一长期存在的教条。我们 证明 AF 细胞可以通过氧化吸收并利用乳酸作为碳源 磷酸化（OXPHOS），从而揭示了 NP 之间依赖于乳酸的代谢共生 和 AF，缺氧的 NP 细胞使乳酸被需氧较多的 AF 细胞利用 通过 OXPHOS 生产碳生物燃料。我们还发现了高水平的 IVD 组蛋白乳酰化，这是一种 新鉴定的组蛋白翻译后修饰 (PTM) 类型，使用乳酸作为 基材前体。组蛋白 PTM 对染色质结构的动态调节至关重要 和基因表达，组蛋白 PTM 失调与发育密切相关 许多疾病。根据我们的初步数据，我们假设盘状乳酸并不像 一种废物副产品，而是作为营养贫乏的椎间盘的重要生物燃料 并通过组蛋白作为椎间盘基因表达编程的重要代谢调节剂 乳酰化。我们提出三个具体目标来检验这一假设：（1）确定是否 乳酸通过组蛋白作为椎间盘基因表达的重要代谢调节剂发挥作用 使用用化学酶抑制剂处理的大鼠椎间盘细胞培养模型进行乳酰化 负责组蛋白乳酰化； (2) 确定椎间盘组蛋白是否乳酰化和乳酸- 与年龄相关的代谢共生功能障碍导致与年龄相关的 IDD 年轻和年老的 Fischer 344 只大鼠； (3) 确定椎间盘中断是否具有乳酸依赖性 代谢共生破坏椎间盘组蛋白乳酰化模式并利用转基因促进 IDD 具有 AF 靶向基因缺失以破坏 AF 乳酸摄取的小鼠模型。完成 拟议的研究将确定组蛋白乳酰化是否发挥表观遗传转录作用 控制椎间盘基质稳态和乳酸依赖性代谢共生的调节。 通过以下方法证明乳酸代谢对与年龄相关的 IDD 的影响 表观遗传基因调控和乳酸依赖性代谢共生的机制将是 确定新的治疗靶点以更有可能治疗 IDD 既新颖又重要 在营养贫乏的环境中取得成功。这将是一种创新方法，具有重大意义 比之前的再生努力取得了进步，之前的再生努力在这种独特的组织中取得了有限的成功。