Moosavi Fatemeh, Hosseini Razieh, Rajaian Hamid, Silva Tiago, Magalhães E Silva Diogo, Saso Luciano, Edraki Najmeh, Miri Ramin, Borges Fernanda, Firuzi Omidreza
Medicinal and Natural Products Chemistry Research Center, Shiraz University of Medical Sciences, Shiraz, Iran; Department of Pharmacology, School of Veterinary Medicine, Shiraz University, Shiraz, Iran.
Department of Pharmacology, School of Veterinary Medicine, Shiraz University, Shiraz, Iran.
Bioorg Med Chem. 2017 Jun 15;25(12):3235-3246. doi: 10.1016/j.bmc.2017.04.026. Epub 2017 Apr 27.
Neurodegenerative disorders, such as Parkinson's disease and Alzheimer's disease, threaten the lives of millions of people and the number of affected patients is constantly growing with the increase of the aging population. Small molecule neurotrophic agents represent promising therapeutics for the pharmacological management of neurodegenerative diseases. In this study, a series of caffeic acid amide analogues with variable alkyl chain lengths, including ACAF3 (C3), ACAF4 (C4), ACAF6 (C6), ACAF8 (C8) and ACAF12 (C12) were synthesized and their neurotrophic activity was examined by different methods in PC12 neuronal cells. We found that all caffeic acid amide derivatives significantly increased survival in PC12 neuronal cells in serum-deprived conditions at 25μM, as measured by the MTT assay. ACAF4, ACAF6 and ACAF8 at 5µM also significantly enhanced the effect of nerve growth factor (NGF) in inducing neurite outgrowth, a sign of neuronal differentiation. The neurotrophic effects of amide derivatives did not seem to be mediated by direct activation of tropomyosin receptor kinase A (TrkA) receptor, since K252a, a potent TrkA antagonist, did not block the neuronal survival enhancement effect. Similarly, the active compounds did not activate TrkA as measured by immunoblotting with anti-phosphoTrkA antibody. We also examined the effect of amide derivatives on signaling pathways involved in survival and differentiation by immunoblotting. ACAF4 and ACAF12 induced ERK1/2 phosphorylation in PC12 cells at 5 and 25µM, while ACAF12 was also able to significantly increase AKT phosphorylation at 5 and 25µM. Molecular docking studies indicated that compared to the parental compound caffeic acid, ACAF12 exhibited higher binding energy with phosphoinositide 3-kinase (PI3K) as a putative molecular target. Based on Lipinski's rule of five, all of the compounds obeyed three molecular descriptors (HBD, HBA and MM) in drug-likeness test. Taken together, these findings show for the first time that caffeic amides possess strong neurotrophic effects exerted via modulation of ERK1/2 and AKT signaling pathways presumably by activation of PI3K and thus represent promising agents for the discovery of neurotrophic compounds for management of neurodegenerative diseases.
神经退行性疾病，如帕金森病和阿尔茨海默病，威胁着数百万人的生命，并且随着老龄化人口的增加，受影响患者的数量在不断增长。小分子神经营养剂是神经退行性疾病药物治疗的有前景的疗法。在本研究中，合成了一系列具有不同烷基链长度的咖啡酸酰胺类似物，包括ACAF3（C3）、ACAF4（C4）、ACAF6（C6）、ACAF8（C8）和ACAF12（C12），并通过不同方法在PC12神经元细胞中检测了它们的神经营养活性。我们发现，通过MTT法测定，所有咖啡酸酰胺衍生物在25μM血清剥夺条件下均能显著提高PC12神经元细胞的存活率。5μM的ACAF4、ACAF6和ACAF8也显著增强了神经生长因子（NGF）诱导神经突生长的作用，这是神经元分化的一个标志。酰胺衍生物的神经营养作用似乎不是由原肌球蛋白受体激酶A（TrkA）受体的直接激活介导的，因为强效TrkA拮抗剂K252a并未阻断神经元存活增强作用。同样，用抗磷酸化TrkA抗体进行免疫印迹检测时，活性化合物也未激活TrkA。我们还通过免疫印迹检测了酰胺衍生物对参与存活和分化的信号通路的影响。5μM和25μM的ACAF4和ACAF12在PC12细胞中诱导ERK1/2磷酸化，而5μM和25μM的ACAF12也能够显著增加AKT磷酸化。分子对接研究表明，与母体化合物咖啡酸相比，ACAF12作为推定的分子靶点与磷脂酰肌醇3-激酶（PI3K）具有更高的结合能。基于Lipinski的五规则，所有化合物在类药性测试中均符合三个分子描述符（HBD、HBA和MM）。综上所述，这些发现首次表明咖啡酰胺通过调节ERK1/2和AKT信号通路具有强大的神经营养作用，推测是通过激活PI3K实现的，因此代表了用于发现治疗神经退行性疾病的神经营养化合物的有前景的药物。
