Treatment of Catecholaminergic Neurodegeneration

(A)遗传性帕金森病（PD）中交感神经中的α-突触核蛋白（AS）沉积：PD导致AS在脑外交感去甲肾上腺素能神经中积聚。与Derek Narendra（神经遗传学分支）合作，我们比较了不同遗传形式的PD神经元内AS沉积的大小。AS沉积在交感神经测定AS-酪氨酸羟化酶（TH）共定位指数在皮肤活检。SNCA、DJ-1、LRRK 2和GBA突变与高AS-TH共定位指数相关，而PRKN突变与此无关。在皮肤活检中计算AS-TH共定位指数可以为识别针对AS的实验性治疗试验（PMID 34076298）的最合适候选者提供信息。 (B)动物模型来测试儿茶酚醛假说：与特拉维夫大学的合作者一起，我们发现施用农药鱼藤酮重现了PD中发现的异常脑神经化学模式，包括自毒儿茶酚醛3，4-二羟基苯乙醛（DOPAL）的积累。我们正在测试是否减少DOPAL的形成和氧化，防止异常的神经化学模式和相关的神经行为异常，在这个模型（PMID 34842277）。 (C)预测LBD治疗反应的计算建模：当患者出现LBD症状时，已经有大量的儿茶酚胺能神经元损失。确定临床前LBD的生物标志物可能对于最大限度地提高疾病改善治疗的有效性至关重要。我们扩展了以前发表的计算模型，该模型结合了多巴胺代谢产物DOPAL与AS的有害相互作用。建模表明，三阶段的损失，从稳态的第一阶段，以动态平衡和快速的儿茶酚胺消耗在第二阶段，以减缓进一步损失的症状第三阶段的儿茶酚胺含量。该模型预测，在从稳态到稳态异常的过渡期抑制DOPAL的产生应能显著延迟症状性LBD的发作。将计算建模与临床实验室生物标志物相结合来检测临床前疾病，可以实现对LBD实验性治疗试验的疾病进展和靶向特异性神经元内功能障碍的个性化预测（PMID 35621196）。 (D)Menkes病的诊断和治疗：Menkes病是一种罕见的铜代谢紊乱，通常在儿童时期是致命的。将多巴胺转化为去甲肾上腺素的酶含有并需要铜。我们正在与俄亥俄州州立大学的研究人员合作，研究门克斯病基因治疗的动物模型，以期将来进行临床试验。我们还签署了一项合作研发协议，内容涉及使用去甲肾上腺素前药L-thre-3，4-dihydroxyphenylserine治疗门克斯病患者的OH。我们继续提供作为公共服务的诊断分析的血浆儿茶酚水平的新生儿在门克斯病的风险，通过我们的CLIA认证的实验室。 (E)托莫西汀治疗认知功能障碍可抑制人脑中的儿茶酚胺再摄取：托莫西汀药物可抑制大脑和外周神经元释放的去甲肾上腺素的再摄取，目前正在轻度认知功能障碍患者中进行测试。与Emory的合作者一起，我们发现托莫西汀治疗产生的脑脊液神经化学模式与大脑中去甲肾上腺素和多巴胺的再摄取减少一致（PMID 34919634）。 (F)硬膜外脊髓刺激治疗脊髓损伤患者的低血压（低血压）：与路易斯维尔大学的研究人员合作，我们正在评估硬膜外脊髓刺激对脊髓损伤后OH患者血浆儿茶酚胺和相关化合物水平的影响。 (G)用于儿茶酚胺相关化合物的LC-MS/MS：通过液相色谱法和电化学检测器进行DOPAL和DOPEGAL的生化测定在技术上受到限制。为了记录实验性治疗措施对DOPAL和DOPEGAL水平的影响，液相色谱串联和飞行时间质谱（LC-MS/MS）似乎具有上级优势。该方法也可用于鉴定人血浆中与咖啡相关的儿茶酚。根据一项技术转让协议，我们正在探索市售LC-MS/MS系统是否能有效测量血浆DOPAL和DOPEGAL。

(A) Alpha-Synuclein (AS) deposition in sympathetic nerves in genetic Parkinson's disease (PD): PD entails AS buildup outside the brain in sympathetic noradrenergic nerves. In collaboration with Derek Narendra (Neurogenetics Branch) we compared magnitudes of intra-neuronal AS deposition across genetic forms of PD. AS deposition in sympathetic nerves was measured by the AS-tyrosine hydroxylase (TH) colocalization index in skin biopsies. SNCA, DJ-1, LRRK2, and GBA mutations were found to be associated with high AS-TH colocalization indexes, whereas PRKN mutations were not. Calculating AS-TH colocalization indexes in skin biopsies may be informative for identifying the most appropriate candidates for experimental therapeutic trials targeting AS (PMID 34076298). (B) Animal model to test the catecholaldehyde hypothesis: With collaborators at the Tel Aviv University we found that administration of the pesticide rotenone reproduces the abnormal brain neurochemical pattern found in PD, including buildup of the autotoxic catecholaldehyde 3,4-dihydroxyphenylacetaldehyde (DOPAL. We are testing whether decreasing DOPAL formation and oxidation prevents the abnormal neurochemical pattern and associated neurobehavioral abnormalities in this model (PMID 34842277). (C) Computational modeling to predict responses to treatment in LBDs: By the time a patient develops symptoms of a LBD, there is already substantial loss of catecholaminergic neurons. Identifying biomarkers of preclinical LBDs may be crucial for maximizing the effectiveness of disease-modifying treatments. We extended on a previously published computational model that incorporates harmful interactions of the dopamine metabolite DOPAL with AS. The modeling indicated tri-phasic loss of catecholamine contents, from homeostasis in the first phase to dyshomeostasis and rapid catecholamine depletion in the second phase to slow further loss in the symptomatic third phase. The model predicts that inhibiting DOPAL production at the transition from homeostasis to dyshomeostasis should substantially delay the onset of symptomatic LBDs. Combining computational modeling with clinical laboratory biomarkers to detect preclinical disease may enable individualized predictions about disease progression and target specific intra-neuronal dysfunctions for experimental therapeutic trials in LBDs (PMID 35621196). (D) Diagnosis and treatment of Menkes disease: Menkes disease is a rare disorder of copper metabolism that usually is lethal in childhood. The enzyme that converts dopamine to norepinephrine contains and requires copper. We are collaborating with investigators at the Ohio State University on animal models of gene therapy treatments for Menkes disease, with a view to a future clinical trial. We also have in place a Cooperative Research and Development Agreement regarding treating OH with the norepinephrine pro-drug L-thre-3,4-dihydroxyphenylserine in Menkes disease patients. We continue to offer as a public service diagnostic assays of plasma levels of catechols in newborns at risk of Menkes disease, via our CLIA-certified laboratory. (E) Atomoxetine to treat cognitive dysfunction inhibits catecholamine reuptake in the human brain: The drug atomoxetine inhibits the reuptake of norepinephrine released from neurons in the brain and periphery and is being tested in people with mild cognitive dysfunction. With collaborators at Emory we found that atomoxetine treatment produces a cerebrospinal fluid neurochemical pattern consistent with decreased reuptake of both norepinephrine and dopamine in the brain (PMID 34919634). (F) Epidural spinal cord stimulation for low blood pressure (hypotension) in patients with spinal cord injury: In collaboration with investigators at the Univ. of Louisville we are evaluating effects of epidural spinal cord stimulation on plasma levels of catecholamines and related compounds in people with OH after spinal cord injury. (G) LC-MS/MS for catecholamine-related compounds: Biochemical assays of DOPAL and DOPEGAL by liquid chromatography with electrochemical detection are limited technologically. To document effects of experimental therapeutic measures on DOPAL and DOPEGAL levels, liquid chromatography with tandem and time of flight mass spectrometry (LC-MS/MS) seems superior. This methodology could also be used to identify coffee-related catechols in human plasma. Under a technology transfer agreement we are exploring whether a commercially available LC-MS/MS system validly measures plasma DOPAL and DOPEGAL.