Muscle building supplement HMB for remyelination

病理上，多发性硬化症(MS)可以通过弥漫的、离散的脱髓鞘区域的存在来识别，称为斑块。脱髓鞘是多发性硬化症的一个主要特征，因此，治疗多发性硬化症的方法包括增加轴突的重新髓鞘形成，从而导致临床改善。过氧化物酶体增殖物激活受体β或δ(PPARβ)在中枢神经系统高表达，参与包括髓鞘形成在内的多种脑功能。作为一种核激素受体，PPARβ的激活和核转位需要配体S的参与。因此，寻找新的PPARβ无毒配体对促进髓鞘再生具有重要意义。β-羟基β-甲基丁酸酯(HMB)在当地的GNC商店可以买到，作为人类肌肉建设的补充。它是人体内通过L亮氨酸代谢产生的一种生理分子。众所周知，HMB可以增加运动引起的肌肉大小和肌肉力量的增加，并改善运动表现。在这里，我们将测试一个令人兴奋的假设，即HMB与PPARβ的配体结合区域(特异性目的I)，以及HMB及其前体L亮氨酸促进OPC成熟(特异性目的II)，并通过OPC特异性和/或小胶质细胞特异性β刺激中枢神经系统脱髓鞘动物模型(铜带区和实验性自身免疫性脑脊髓炎)的再髓鞘形成(特异性目的III)。为了研究L亮氨酸和人血清白蛋白的肌肉生长效应是否有助于改善铜宗和EAE模型的运动功能，特定目的III还将研究骨骼肌特异性PPARβ的作用。这项前沿的R01提案的积极成果将描绘出易于获得的肌肉生成补充剂HMB作为PPARβ的生理配体，并增加促进再髓鞘形成和使用HMB及其前体L亮氨酸作为主要或辅助疗法治疗MS和其他脱髓鞘疾病患者的可能性。

Pathologically, multiple sclerosis (MS) can be identified by the presence of diffuse, discrete demyelinated areas, called plaques. Demyelination is a major feature of MS and therefore, an approach to the management of MS involves an increase in remyelination of axons, resulting in clinical improvement. Peroxisome proliferator-activated receptor β or δ (PPARβ) being highly expressed in the CNS participates in many brain functions including myelination. Being a nuclear hormone receptor, PPARβ needs ligand(s) for its activation and nuclear translocation. Therefore, identification of new nontoxic ligand of PPARβ would be very important for promoting remyelination. The β-hydroxy β-methylbutyrate (HMB) is available in local GNC stores as a muscle-building supplement in human. It is a physiological molecule that is produced in human through the metabolism of L-leucine. HMB is known to increase exercise-induced gains in muscle size and muscle strength and improve exercise performance. Here, we will test an exciting hypothesis that HMB binds to the ligand-binding domain of PPARβ (Specific aim I) and that HMB and its precursor L-leucine promote maturation of OPCs (Specific aim II) and stimulate remyelination in animal models (cuprizone and experimental autoimmune encephalomyelitis or EAE) of CNS demyelination (Specific aim III) via OPC-specific and/or microglia-specific PPARβ. To investigate whether the muscle building effects of L-leucine and HMB could contribute to improved motor function in cuprizone and EAE models, Specific aim III will also examine the role of skeletal muscle-specific PPARβ. A positive outcome of this cutting-edge R01 proposal will delineate easily available muscle-building supplement HMB as a physiological ligand of PPARβ and enhance the possibility of promoting remyelination and treating patients with MS and other demyelinating disorders with HMB and its precursor L-leucine as primary or adjunct therapy.