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Revealing the essential functions of mitochondrial NADPH and NADK2 for cell growth and proliferation

揭示线粒体 NADPH 和 NADK2 对细胞生长和增殖的基本功能

基本信息

批准号：
10364228
负责人：
Gerta N/A Hoxhaj
金额：
$ 32.8万
依托单位：
UT SOUTHWESTERN MEDICAL CENTER
依托单位国家：
美国
项目类别：
财政年份：
2021
资助国家：
美国
起止时间：
2021-09-15 至 2026-08-31
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10364228
关键词：
Adenine Affect Anabolism Antioxidants Biochemical Biology Biomass Cell Proliferation Cells Cellular Metabolic Process Coupled Data Development Disease Drug Metabolic Detoxication Energy Supply Enzymes Exhibits Future Glucose Glutamine Goals Growth Health Health Benefit Homeostasis Human Human Cell Line Hypoxanthines Isotopes Knock-out Lipids Maintenance Malignant Neoplasms Mammalian Cell Mass Spectrum Analysis Measurement Mediating Metabolic Methods Mitochondria Molecular Mutation NAD+ kinase NADP Neurodegenerative Disorders Neurologic Neurologic Symptoms Nucleotide Biosynthesis Nucleotides Oxidation-Reduction Oxidative Stress Pathway interactions Patients Phenotype Phosphatidylinositols Phosphorylation Phosphotransferases Production Proliferating Proline Protein Biosynthesis Reactive Oxygen Species Role Science Source Supplementation Supporting Cell Symptoms Testing Therapeutic Therapeutic Intervention Withdrawal cell growth cofactor combat developmental disease dietary restriction enzyme biosynthesis experimental study gene synthesis in vivo macromolecule mutant nervous system disorder novel therapeutic intervention nucleotide metabolism tumor tumor growth

项目摘要

SUMMARY: To grow and proliferate, cells need to fulfill three key metabolic demands: increased biosynthesis, sufficient energy supply, and maintenance of redox homeostasis. The latter demand is particularly important for sustained growth, because increased rate of cellular metabolic activity during cell proliferation results in elevated levels of reactive oxygen species (ROS), which can have detrimental effects on cell growth. Nicotinamide adenine dinucleotide phosphate (NADPH) is a principal supplier of reducing power for biosynthesis of macromolecules and protection against oxidative stress. The total cellular pool of NADPH is regulated by the activity of NAD kinases (NADK), enzymes that catalyze the phosphorylation of NAD+ to NADP+, the rate-limiting substrate for NADPH production. Mammalian cells express two NAD kinases, cytosolic NADK, and mitochondrial NADK2, which generate compartment-specific reducing power. Recently, we discovered that the activity of NADK is stimulated by the phosphoinositide 3-kinase (PI3K) - Akt pathway to boost the NADP(H) production for cell growth, but the importance of NADK2 and the overall role of mitochondrial NADPH in cell growth has yet to be established. Mutations in NADK2 have been observed in patients with various neurological and developmental disorders. Therefore, defining the key functions of NADK2 and mitochondrial NADP(H) is critical and relevant to human health. This proposal builds on our finding that decreasing mitochondrial NADP(H) levels through depletion of NADK2 renders cells uniquely proline auxotroph. Cells with NADK2 deletion fail to synthesize proline and rely on exogenous proline for their growth. Proline is critical for protein synthesis, and, unexpectedly, for nucleotide synthesis, in NADK2-deficient cells. We propose three Specific Aims to establish the functions of NADK2 and mitochondrial NADP(H) that are essential for cell growth and proliferation and relevant for proliferative diseases and NADK2 deficiency in humans. In Aim 1, we propose to define the molecular mechanisms by which NADK2 and mitochondrial NADPH support proline biosynthesis and evaluate the effects of NADK2 patient mutations on proline synthesis. In Aim 2, we will determine the mechanisms of how NADK2 deficiency and reduced proline abundance affect flux through the de novo and salvage nucleotide synthesis pathways. In Aim 3, we will assess the requirement of NADK2 and mitochondrial NADPH for tumor growth and evaluate the therapeutic potential of targeting NADK2 in combination with dietary restriction of proline. This proposal will establish the primary functions of mitochondrial NADP(H) and NADK2 that are essential for cell growth and proliferation, thereby informing us on new therapeutic strategies to combat proliferative diseases and NADK2 deficiency in humans.

摘要：为了生长和增殖，细胞需要满足三个关键的代谢需求：增加生物合成；