The role of proline metabolism during osteoblast differentiation and bone formation

脯氨酸代谢在成骨细胞分化和骨形成中的作用

基本信息

批准号：
10046912
负责人：
Courtney Michael Karner
金额：
$ 7.2万
依托单位：
DUKE UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2020
资助国家：
美国
起止时间：
2020-08-10 至 2020-10-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10046912
关键词：
ATP Synthesis Pathway Address Affect Alleles American Amino Acid Transporter Amino Acids Anabolism Back Bone Development Bone Matrix Bone Regeneration Bone Resorption Cell Proliferation Cell Survival Cells Collagen Complex Consumption Coupling Data Defect Disease Disease Progression Electron Transport Electrons Enzymes Glycolysis Health Care Costs Homeostasis Imino Acids In Vitro Individual Knowledge Maintenance Membrane Metabolic Metabolism Molecular Mus NADH Natural regeneration Neutral Amino Acid Transport Systems Osteoblasts Osteogenesis Osteopenia Osteoporosis Oxides Pathway interactions Patients Pentosephosphate Pathway Pharmaceutical Preparations Physiologic Ossification Physiological Process Production Proline Proline Dehydrogenase Protein Biosynthesis Proteins Regulation Role System WNT Signaling Pathway Work aminoacid biosynthesis base bone bone mass bone quality cancer cell carboxylate extracellular genetic approach in vitro activity in vivo metabolomics new therapeutic target osteoblast differentiation oxidation polypeptide prevent progenitor proline permease pyrroline pyrroline 5 carboxylate reductase repaired skeletal uptake

项目摘要

Project Summary: Proline is a multifunctional imino acid with myriad uses in the cell. Aside from direct incorporation into protein, proline can be metabolized via a process known as the proline cycle. Here, proline is oxidized by proline oxidase (PRODH) to form D1-pyrroline-5-carboxylate (P5C). PRODH is a FAD+ dependent enzyme that donates electrons to complex II of the mitorchondrial electron transport chain thus coupling proline oxidation to ATP synthesis. P5C is converted back into proline by the NADH dependent enzyme pyrroline-5-carboxylate reductase (PYCR) to provide reducing power for glycolysis and the pentose phosphate pathways. It is unknown how osteoblasts obtain proline, how proline uptake is regulated, or if and when the proline cycle is required during differentiation. Osteoblasts express a diverse array of membrane-tethered amino acid transporters to facilitate proline uptake. We have identified the system A neutral amino acid transporter SNAT2 (encoded by Slc38a2) as the most highly expressed putative proline transporter in osteoblasts. Our preliminary data indicates WNT stimulates proline uptake through SNAT2 that is necessary for osteoblast differentiation in vitro. Moreover, mice homozygous for a null allele of Slc38a2 (Slc38a2-/-) have defects in endochondral ossification. In this proposal, we will 1) establish the necessity of proline uptake through Slc38a2/SNAT2 to regulate osteoblast differentiation and bone formation in vivo, 2) determine how SNAT2 activity is regulated by WNT signaling and 3) elucidate the necessity of proline metabolism via the proline cycle in differentiating osteoblasts. Our findings will have broad implications in bone development, maintenance of bone mass, skeletal repair and regeneration.

项目概要：脯氨酸是一种多功能亚氨基酸，在细胞中具有多种用途。除了直接掺入蛋白质之外，脯氨酸可以通过称为脯氨酸循环的过程进行代谢。此处，脯氨酸被脯氨酸氧化氧化酶 (PRODH) 形成 D1-吡咯啉-5-羧酸酯 (P5C)。 PRODH 是一种 FAD+ 依赖性酶，向线粒体电子传递链的复合体 II 提供电子，从而将脯氨酸氧化偶联 ATP 合成。 P5C 通过 NADH 依赖性酶吡咯啉-5-羧酸盐转化回脯氨酸还原酶 (PYCR) 为糖酵解和磷酸戊糖途径提供还原能力。这是未知成骨细胞如何获得脯氨酸，如何调节脯氨酸摄取，或者脯氨酸循环是否以及何时进行分化过程中需要。成骨细胞表达多种膜束缚氨基酸转运蛋白以促进脯氨酸的吸收。我们已经鉴定出A系统中性氨基酸转运蛋白 SNAT2（由 Slc38a2 编码）是成骨细胞中表达最高的假定脯氨酸转运蛋白。我们的初步数据表明 WNT 通过 SNAT2 刺激脯氨酸摄取，这是成骨细胞所必需的体外分化。此外，Slc38a2 无效等位基因 (Slc38a2-/-) 的纯合小鼠存在以下缺陷：软骨内骨化。在本提案中，我们将 1) 通过以下方式确定脯氨酸摄取的必要性： Slc38a2/SNAT2在体内调节成骨细胞分化和骨形成，2）确定SNAT2如何活性受 WNT 信号传导调节，3) 阐明通过脯氨酸循环进行脯氨酸代谢的必要性在分化成骨细胞方面。我们的研究结果将对骨骼发育、维持骨量、骨骼修复和再生。