Restoring Ocrl1 function in Lowe Syndrome and Dent-2 disease

恢复 Lowe 综合征和 Dent-2 疾病中的 Ocrl1 功能

• 批准号: 10491249
• 负责人: Ruben Claudio Aguilar
• 金额: $ 34.49万
• 依托单位: PURDUE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-09-20 至 2026-06-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10491249
• 关键词: Active Sites; Address; Adolescence; Affect; Affinity; Age; Algorithms; Allosteric Site; Animal Model; Behavior; Binding; Biological Models; Birth; Cataract; Cell Line; Cessation of life; Child; Complement; Dextrans; Disease; Enzyme Kinetics; Enzymes; Equilibrium; FDA approved; Genes; Genetic Diseases; Glaucoma; In Vitro; Investigation; Kidney; Kidney Calculi; Kidney Failure; Lead; Lipids; Maps; Measurement; Mental Retardation; Missense Mutation; Modeling; Modification; Molecular Conformation; Mutate; Mutation; Nature; Oculocerebrorenal Syndrome; Organoids; Oxalates; Patients; Pharmaceutical Preparations; Phenotype; Phosphoric Monoester Hydrolases; Process; Proteins; Proteinuria; Publishing; Renal function; Research; Risk Management; Safety; Series; Structure; Symptoms; Techniques; Testing; Therapeutic; Therapeutic Agents; Therapeutic Index; Toxic effect; Toxicology; Variant; Zebrafish; cilium biogenesis; conformer; design; disease-causing mutation; drug action; drug candidate; experimental study; kidney cell; mutant; novel therapeutic intervention; patient subsets; remediation; small molecule; translational impact; uptake

Lowe Syndrome (LS) is a disease caused by mutations in the OCRL1 gene that unfortunately leads to the early death of affected children and has no cure. However, this project aims to change such scenario. Further, since OCRL1 mutations also cause a related renal condition known as Dent-2 (D2) disease, this proposal will also benefit D2 patients. LS patients display mental retardation, ocular (e.g., glaucoma, cataracts) and renal (e.g., kidney stones, LMW proteinuria) abnormalities, while D2 patients show renal symptoms almost exclusively. Although most OCRL1 missense mutations found in patients alter the phosphatase domain of the encoded protein Ocrl1, about half of these changes do not affect residues involved in binding or modification of the substrate. In fact, our results indicate that a substantial number of patients express Ocrl1 mutated proteins with intact binding/catalytic sequences but locked in a conformation unable to process lipid substrates. Therefore, we HYPOTHESIZE that a subset of Ocrl1 patient mutated proteins can re-acquire functionality by action of drugs able to stabilize the enzymatically active conformer (allosteric activators). Indeed, as a result of a series of small molecule screens performed in our lab, we identified a group of compounds (including FDA-approved drugs) as able to restore catalytic activity of different Ocrl1 patient mutants and to suppress a readout LS/D2 cellular phenotype. To test our hypothesis, 4 allosteric activator candidates will be used along with a panel of LS and D2 Ocrl1 patient mutated variants to pursue the following specific aims focused on kidney function: AIM 1. To determine the in vitro effect of selected candidate drugs ON THE BIOCHEMICAL ACTIVITY of a panel of Ocrl1 LS/D2 patient mutated variants. AIM 2. To determine the effect of selected candidate drugs ON MULTIPLE LS PHENOTYPES observed in kidney cell lines, kidney organoids and a zebrafish animal model bearing LS/D2 patient OCRL1 mutations. AIM 3. To determine the effect of selected candidate drugs ON THE STABILITY AND STRUCTURE of the Ocrl1 LS/D2 mutated variants bound or not to substrate. This project is INNOVATIVE because it introduces the concept of LS and D2 as heterogenous conditions with some patients displaying a conformational/misfolding disease component and proposes a novel therapeutic approach using allosteric activators. Importantly, this project has high SIGNIFICANCE as it will address the lack of therapeutic approaches designed to suppress the upstream cause of a disease that affects tens of thousands of children in the US and worldwide. Further, FDA-approved candidate drugs currently used to ameliorate other conditions can be readily repurposed to LS/D2. Therefore, the translational IMPACT of this project is very high.

Lowe综合征（LS）是由OCRL1基因突变引起的疾病，不幸的是导致 受影响儿童的早期死亡，无法治愈。但是，该项目旨在改变这种情况。更远， 由于OCRL1突变也会引起相关的肾脏条件，称为Dent-2（D2）疾病，因此该建议将 也使D2患者受益。 LS患者表现出智力低下，眼部（例如青光眼，白内障）和肾脏（例如，肾结石， LMW蛋白尿）异常，而D2患者几乎完全表现出肾脏症状。虽然大多数 患者发现的OCRL1错义突变改变了编码蛋白OCRL1的磷酸酶结构域，大约 其中一半的变化不影响涉及底物结合或修饰的残基。实际上，我们的 结果表明，大量患者表达具有完整结合/催化的OCRL1突变蛋白 序列但锁定的构象无法处理脂质底物。因此，我们假设 OCRL1患者突变蛋白的子集可以通过能够稳定的药物来重新获得功能 酶活性构象异构体（变构激活剂）。确实，由于一系列小分子 在我们的实验室进行的屏幕，我们确定了一组化合物（包括FDA批准的药物）能够 恢复不同OCRL1患者突变体的催化活性并抑制读数LS/D2细胞表型。 为了检验我们的假设，将使用4个变构激活因子与LS和D2 OCRL1一起使用 患者突变的变体以追求以下特定目的，重点是肾功能： 目标1。确定选定候选药物对面板生化活性的体外作用 OCRL1 LS/D2患者突变变体的。 目标2。确定选定候选药物对肾脏中观察到的多种LS表型的影响 细胞系，肾脏器官和带有LS/D2患者OCRL1突变的斑马鱼动物模型。 目标3。确定选定候选药物对OCRL1稳定性和结构的影响 LS/D2突变变体与底物结合或不结合。 该项目具有创新性，因为它将LS和D2的概念引入 一些显示构象/错误折叠疾病成分的患者并提出了一种新的治疗性 使用变构激活器的方法。重要的是，该项目具有很高的意义，因为它将解决缺乏 治疗方法旨在抑制影响成千上万的疾病的上游原因 美国和全球的孩子。此外，FDA批准的候选药物目前用于改善其他 条件很容易重新利用为LS/D2。因此，该项目的翻译影响很高。