DataSheet2_v1_Scabronine G Methyl Ester Improves Memory-Related Behavior and Enhances Hippocampal Cell Proliferation and Long-Term Potentiation via the BDNF-CREB Pathway in Olfactory Bulbectomized Mice.PDF

A previous study reported that scabronine G methyl ester (SG-ME) potentially enhances the in vitro secretion of neurotrophic factors such as nerve growth factor via the protein kinase C (PKC)-ζ pathway. However, it remains unknown whether SG-ME can improve cognitive dysfunctions in olfactory bulbectomized (OBX) mice. To address this question, we evaluated SG-ME-treated and untreated OBX mice in a passive avoidance test. We also investigated potential effects of SG-ME on several parameters: cell proliferation and cAMP response element-binding protein (CREB) phosphorylation in the hippocampal dentate gyrus by immunohistochemistry, brain-derived neurotrophic factor (BDNF) levels in the hippocampus by Western blotting, p-CREB levels in the hippocampus by MapAnalyzer, and long-term potentiation (LTP) by electrophysiology. On the 14th day after surgery OBX mice showed altered passive avoidance and decreases in both cell proliferation and long-term potentiation in the hippocampus, while these changes were reversed by SG-ME (20 μg/mouse) 24 h after the treatment. The improvement in memory deficits was prevented when SG-ME was co-administeredwith either zeta inhibitory peptide (PKC-ζ inhibitor), anti-BDNF antibody, ANA-12 (TrkB antagonist), U0126 (MEK inhibitor), H-89 (PKA inhibitor), LY294002 (PI3K inhibitor) or KN-93 (CaMKII inhibitor). We found that SG-ME enhanced brain-derived neurotrophic factor and p-CREB levels in the hippocampus while p-CREB was localized in neurons, but not in astrocytes nor microglial cells. These findings revealed the potential of SG-ME in improving memory impairments by enhancing cell proliferation and LTP via activation of the BDNF/CREB signaling pathway in neurons.

既往研究表明，雪蟹菌素G甲酯（scabronine G methyl ester, SG-ME）可通过蛋白激酶Cζ（protein kinase C ζ, PKC-ζ）通路，在体外促进神经生长因子（nerve growth factor）等神经营养因子的分泌。然而，SG-ME是否能够改善嗅球切除（olfactory bulbectomized, OBX）小鼠的认知功能障碍，目前仍不明确。为解答这一问题，我们对经SG-ME处理与未处理的OBX小鼠开展了被动回避实验（passive avoidance test）评估。同时，我们还检测了SG-ME的多项潜在作用效应：通过免疫组织化学（immunohistochemistry）检测海马齿状回（hippocampal dentate gyrus）的细胞增殖与环腺苷酸反应元件结合蛋白（cAMP response element-binding protein, CREB）磷酸化水平；通过蛋白质印迹（Western blotting）检测海马脑源性神经营养因子（brain-derived neurotrophic factor, BDNF）含量；通过MapAnalyzer检测海马p-CREB水平；通过电生理（electrophysiology）检测长时程增强（long-term potentiation, LTP）情况。术后第14天，OBX小鼠出现被动回避行为异常，且海马齿状回的细胞增殖与LTP水平均出现下降；而SG-ME（20 μg/只小鼠）给药24小时后可逆转上述变化。若SG-ME与ζ抑制肽（zeta inhibitory peptide, PKC-ζ抑制剂）、抗BDNF抗体、ANA-12（TrkB拮抗剂）、U0126（MEK抑制剂）、H-89（PKA抑制剂）、LY294002（PI3K抑制剂）或KN-93（CaMKII抑制剂）联合给药，则可阻断SG-ME对记忆缺陷的改善作用。我们发现，SG-ME可提升海马内BDNF与p-CREB的水平，且p-CREB定位于神经元，而非星形胶质细胞或小胶质细胞。上述研究结果揭示，SG-ME可通过激活神经元内的BDNF/CREB信号通路，促进细胞增殖与LTP，从而改善记忆损伤，具备潜在的应用价值。