Geniposide Ameriorated Fluoxetine-Suppressed Neurite Outgrowth in Neuro2a Neuroblastoma Cells

• Main Authors: Chen, Ming-Kai, 陳明楷
• Other Authors: Hsieh, Chiu-Lan
• Format: Others
• Language: zh-TW
• Published: 2017
• Online Access: http://ndltd.ncl.edu.tw/handle/t3z3mh

碩士 === 國立彰化師範大學 === 生物學系 === 105 === Patients affiliated with neurodegenerative diseases like Alzheimer's disease, Schizophrenia and depression usually may lose physical vitality and life quality. Most of the findings have attributed to the cause inducing such mental disorders to be due to dysfunction of neuronal circuit. Neurite outgrowth is the main marker associated with neuronal differentiation, which acts as the crucial role adhering to the development of neuronal function. During the neuronal differentiation process, serial evolutional stage-dependent changes may take place, including neurite elongation, neurite branching, growth of dendrites and axons. Alprazolam, available under the trade name Xanax, is a potent, short-acting anxiolytic of the benzodiazepine class —a minor tranquilize. Fluoxetine (FXT, trade name Prozac), a selective serotonin reuptake inhibitor (SSRI), is the most common psychiatric medications clinically prescribed. While over-produced serotonin can suppress neurite development. The role of major iridoid glycosides of Gardenia jasminoides [geniposide (GPS), geniposidic acid (GPSA), and genipin (GNP)] in ameliorating the side effect of FXT (anti-neurite development), is poorly understood. To uncover this, we performed this investigation. FXT (5 µM) decreased the neurite outgrowth in Neuro2a cells. While APZ seemed not to have shown any significant effect.GPS (100 and 200 µM) and GNP (20 µM) ameliorated and increased the percentage of neurite bearing Neuro2a cells. While GPSA seemed not to have shown any significant effect. Cotreatment of FXT (5 µM) with GPS (100 and 200 µM) or GNP (10 and 20 µM) showed that GPS but not GNP was more effective with respect to the stimulation of neurite bearing cell counts. FXT downregulated the gene expression for neurite outgrowth target markers like microtubule-associated protein-2 (MAP2) and growth-associated protein 43 (GAP43). In contrast, GPS upregulated MAP2, GAP43 and TUBB3, otherwise, attenuated the downregulated MAP2 and GAP43 gene expression caused by FXT in Neuro2a cells. Interestingly, results obtained from the immunofluorescence staining showed that FXT decreased the protein expression of GAP43. GPS stimulated the production of MAP2 and GAP43, and at the same time, attenuated the suppressed GAP43 level caused by FXT in Neuro2a cells. Additionally, GPS securded the p-CREB expression in FXT-treated Neuro2a cells, and the activation of CREB is dependent on the ERK/MAPK and AKT/mTOR signaling pathways. Conclusively, this study has provided a valuable information regarding the possible cellular and molecular mechanisms showing how FXT exerts its detrimental side-effects on the neuronal differentiation, and via the same mechanism how GPS attenuated these side effects. Thus, it is suggested that the distinguished adjuvant role of Geniposide should be considered whenever prescribing Fluoxetine for clinical uses.