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：
10440352
负责人：
Courtney Michael Karner
金额：
$ 32.15万
依托单位：
UT SOUTHWESTERN MEDICAL CENTER
依托单位国家：
美国
项目类别：
财政年份：
2020
资助国家：
美国
起止时间：
2020-08-10 至 2025-07-31
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10440352
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.

项目摘要：脯氨酸是一种多功能伊米诺氨酸，在细胞中使用了无数。除了直接掺入蛋白质外，脯氨酸可以通过称为脯氨酸循环的过程代谢。在这里，脯氨酸被脯氨酸氧化氧化酶（prodh）形成D1-吡咯氨酸-5-羧酸盐（P5C）。 prodh是一种时尚+依赖性酶将电子捐赠给Mitorondrial电子传输链的复合物II，从而将脯氨酸氧化耦合到 ATP合成。 P5C通过依赖NADH的吡咯氨酸-5-羧酸盐将P5C转化为脯氨酸还原酶（PYCR）可为糖酵解和磷酸五磷酸戊糖途径提供还原功率。这是未知的成骨细胞如何获得脯氨酸，如何调节脯氨酸的摄取，或者是否以及脯氨酸循环是何时的调节在区分过程中需要。成骨细胞表达各种膜系氨基酸阵列转运蛋白以促进脯氨酸的吸收。我们已经确定了系统中性氨基酸转运蛋白 SNAT2（由SLC38A2编码）是成骨细胞中最高表达的推定脯氨酸转运蛋白。我们的初步数据表明Wnt刺激了通过SNAT2刺激脯氨酸的吸收，这对于成骨细胞是必需的体外分化。此外，纯合的小鼠SLC38A2（SLC38A2 - / - ）的无效等位基因中有缺陷内软骨骨化。在此提案中，我们将1）确定脯氨酸吸收的必要性 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）通过脯氨酸循环阐明了脯氨酸代谢的必要性在区分成骨细胞中。我们的发现将对骨骼发育有广泛的影响，维护骨骼质量，骨骼修复和再生。