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Oral Administration of Gintonin Attenuates Cholinergic Impairments by Scopolamine, Amyloid-β Protein, and Mouse Model of Alzheimer's Disease.

Kim HJ, Shin EJ, Lee BH, Choi SH, Jung SW, Cho IH, Hwang SH, Kim JY, Han JS, Chung C, Jang CG, Rhim H, Kim HC, Nah SY - Mol. Cells (2015)

Bottom Line: The brains of AD patients show a reduction in acetylcholine concentration caused by cholinergic system impairments.In this study, we used gintonin to investigate the effect of LPA receptor activation on the cholinergic system in vitro and in vivo using wild-type and AD animal models.Furthermore, this study showed that gintonin could be a novel agent for the restoration of cholinergic system damages due to Aβ and could be utilized for AD prevention or therapy.

View Article: PubMed Central - PubMed

Affiliation: Ginsentology Research Laboratory and Department of Physiology, College of Veterinary Medicine, Konkuk University, Seoul 143-701, Korea.

ABSTRACT
Gintonin is a novel ginseng-derived lysophosphatidic acid (LPA) receptor ligand. Oral administration of gintonin ameliorates learning and memory dysfunctions in Alzheimer's disease (AD) animal models. The brain cholinergic system plays a key role in cognitive functions. The brains of AD patients show a reduction in acetylcholine concentration caused by cholinergic system impairments. However, little is known about the role of LPA in the cholinergic system. In this study, we used gintonin to investigate the effect of LPA receptor activation on the cholinergic system in vitro and in vivo using wild-type and AD animal models. Gintonin induced [Ca(2+)]i transient in cultured mouse hippocampal neural progenitor cells (NPCs). Gintonin-mediated [Ca(2+)]i transients were linked to stimulation of acetylcholine release through LPA receptor activation. Oral administration of gintonin-enriched fraction (25, 50, or 100 mg/kg, 3 weeks) significantly attenuated scopolamine-induced memory impairment. Oral administration of gintonin (25 or 50 mg/kg, 2 weeks) also significantly attenuated amyloid-β protein (Aβ)-induced cholinergic dysfunctions, such as decreased acetylcholine concentration, decreased choline acetyltransferase (ChAT) activity and immunoreactivity, and increased acetylcholine esterase (AChE) activity. In a transgenic AD mouse model, long-term oral administration of gintonin (25 or 50 mg/kg, 3 months) also attenuated AD-related cholinergic impairments. In this study, we showed that activation of G protein-coupled LPA receptors by gintonin is coupled to the regulation of cholinergic functions. Furthermore, this study showed that gintonin could be a novel agent for the restoration of cholinergic system damages due to Aβ and could be utilized for AD prevention or therapy.

No MeSH data available.


Related in: MedlinePlus

Effects of gintonin (GT) on [Ca2+]i transients in neural progenitor cells (NPCs) and its signal transduction. (A) A representative trace obtained after gintonin treatment in NPCs. Gintonin treatment (0.03–3 μg/ml) induces a [Ca2+]i transient. (B) Concentration-response relationship curve for gintonin-induced [Ca2+]i transients in NPCs. Each point represents the mean ± S.E.M. (n = 3–4). (C–E) Representative traces of gintonin-mediated [Ca2+]i transients in the absence or presence of various antagonists. The arrows indicate the application of gintonin (1 μg/ml). An LPA1/3 receptor antagonist (Ki16425, 10 μM), PLC inhibitor (U73122, 5 μM), or Ca2+ chelator (BAPTA-AM, 50 μM) was added before gintonin application. (F) Histograms representing net increases of gintonin-mediated [Ca2+]i transients calculated from traces obtained in the absence or presence of various pharmacological agents. Effect of gintonin (0, 0.3, 1, 3, 10, and 30 μg/ml) and BAPTA-AM (B), a calcium chelator, (50 μM) on acetylcholine release in the NPCs, determined using an Amplex Red Acetylcholine/Acetylcholinesterase Assay Kit (Invitrogen, #A12217). Ki16425 (Ki) also significantly attenuated gintonin-mediated acetylcholine release. NPCs were pretreated with BAPTA or Ki16425 for 1 h before gintonin treatment and then treated with gintonin or each ginsenoside for 16 h. Each value is the mean ± S.E.M. (n = 5). *P < 0.05 vs. control; #P < 0.05 or ##P < 0.01 vs. GT (3 μg/ml).
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f1-molce-38-9-796: Effects of gintonin (GT) on [Ca2+]i transients in neural progenitor cells (NPCs) and its signal transduction. (A) A representative trace obtained after gintonin treatment in NPCs. Gintonin treatment (0.03–3 μg/ml) induces a [Ca2+]i transient. (B) Concentration-response relationship curve for gintonin-induced [Ca2+]i transients in NPCs. Each point represents the mean ± S.E.M. (n = 3–4). (C–E) Representative traces of gintonin-mediated [Ca2+]i transients in the absence or presence of various antagonists. The arrows indicate the application of gintonin (1 μg/ml). An LPA1/3 receptor antagonist (Ki16425, 10 μM), PLC inhibitor (U73122, 5 μM), or Ca2+ chelator (BAPTA-AM, 50 μM) was added before gintonin application. (F) Histograms representing net increases of gintonin-mediated [Ca2+]i transients calculated from traces obtained in the absence or presence of various pharmacological agents. Effect of gintonin (0, 0.3, 1, 3, 10, and 30 μg/ml) and BAPTA-AM (B), a calcium chelator, (50 μM) on acetylcholine release in the NPCs, determined using an Amplex Red Acetylcholine/Acetylcholinesterase Assay Kit (Invitrogen, #A12217). Ki16425 (Ki) also significantly attenuated gintonin-mediated acetylcholine release. NPCs were pretreated with BAPTA or Ki16425 for 1 h before gintonin treatment and then treated with gintonin or each ginsenoside for 16 h. Each value is the mean ± S.E.M. (n = 5). *P < 0.05 vs. control; #P < 0.05 or ##P < 0.01 vs. GT (3 μg/ml).

Mentions: In previous reports, we showed that gintonin derived from ginseng is a novel ligand for LPA receptors (Hwang et al., 2012a). Since LPA receptors are well expressed during the developmental stages of the brain (Hecht et al., 1996) and LPA promotes differentiation of rat embryonic neural stem cells to cholinergic neurons (Cui and Qiao, 2006), we examined the effects of gintonin on the coupling of [Ca2+]i transients to acetylcholine release using cultured hippocampal NPCs, which mainly express the LPA1 receptor (Sun et al., 2010). We first examined the effects of gintonin on [Ca2+]i transients in hippocampal NPCs. As shown in Figs. 1A and 1B, gintonin treatment induced a transient rise of [Ca2+]i in NPCs in a reversible and concentration-dependent manner. The EC50 was 0.21 ± 0.03 μg/ml. Gintonin-induced [Ca2+]i transients were initiated without a detectable lag and reached peak values within a few seconds, and [Ca2+]i gradually decreased and returned to basal level. We observed that treatment of NPC12 cells with LPA C18:1 also induced a [Ca2+]i transient, similar to gintonin (data not shown). We examined the effects of gintonin on [Ca2+]i transients in the absence or presence of the LPA1/3 receptor antagonist Ki16425. As shown in Figs. 1C and 1E, the presence of Ki16425 significantly attenuated the gintonin-mediated [Ca2+]i transient. The active phospholipase C inhibitor U73122, the inositol 1,4,5-triphosphate receptor antagonist 2-APB, and the intracellular Ca2+ chelator BAPTA-AM all blocked gintonin-mediated [Ca2+]i transients in NPCs (Figs. 1D and 1E). These results show that gintonin, via activation of the LPA receptor-phospholipase C-intracellular IP3 receptor signaling transduction pathway, elicits the release of Ca2+ from intracellular stores to increase [Ca2+]i.


Oral Administration of Gintonin Attenuates Cholinergic Impairments by Scopolamine, Amyloid-β Protein, and Mouse Model of Alzheimer's Disease.

Kim HJ, Shin EJ, Lee BH, Choi SH, Jung SW, Cho IH, Hwang SH, Kim JY, Han JS, Chung C, Jang CG, Rhim H, Kim HC, Nah SY - Mol. Cells (2015)

Effects of gintonin (GT) on [Ca2+]i transients in neural progenitor cells (NPCs) and its signal transduction. (A) A representative trace obtained after gintonin treatment in NPCs. Gintonin treatment (0.03–3 μg/ml) induces a [Ca2+]i transient. (B) Concentration-response relationship curve for gintonin-induced [Ca2+]i transients in NPCs. Each point represents the mean ± S.E.M. (n = 3–4). (C–E) Representative traces of gintonin-mediated [Ca2+]i transients in the absence or presence of various antagonists. The arrows indicate the application of gintonin (1 μg/ml). An LPA1/3 receptor antagonist (Ki16425, 10 μM), PLC inhibitor (U73122, 5 μM), or Ca2+ chelator (BAPTA-AM, 50 μM) was added before gintonin application. (F) Histograms representing net increases of gintonin-mediated [Ca2+]i transients calculated from traces obtained in the absence or presence of various pharmacological agents. Effect of gintonin (0, 0.3, 1, 3, 10, and 30 μg/ml) and BAPTA-AM (B), a calcium chelator, (50 μM) on acetylcholine release in the NPCs, determined using an Amplex Red Acetylcholine/Acetylcholinesterase Assay Kit (Invitrogen, #A12217). Ki16425 (Ki) also significantly attenuated gintonin-mediated acetylcholine release. NPCs were pretreated with BAPTA or Ki16425 for 1 h before gintonin treatment and then treated with gintonin or each ginsenoside for 16 h. Each value is the mean ± S.E.M. (n = 5). *P < 0.05 vs. control; #P < 0.05 or ##P < 0.01 vs. GT (3 μg/ml).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4588723&req=5

f1-molce-38-9-796: Effects of gintonin (GT) on [Ca2+]i transients in neural progenitor cells (NPCs) and its signal transduction. (A) A representative trace obtained after gintonin treatment in NPCs. Gintonin treatment (0.03–3 μg/ml) induces a [Ca2+]i transient. (B) Concentration-response relationship curve for gintonin-induced [Ca2+]i transients in NPCs. Each point represents the mean ± S.E.M. (n = 3–4). (C–E) Representative traces of gintonin-mediated [Ca2+]i transients in the absence or presence of various antagonists. The arrows indicate the application of gintonin (1 μg/ml). An LPA1/3 receptor antagonist (Ki16425, 10 μM), PLC inhibitor (U73122, 5 μM), or Ca2+ chelator (BAPTA-AM, 50 μM) was added before gintonin application. (F) Histograms representing net increases of gintonin-mediated [Ca2+]i transients calculated from traces obtained in the absence or presence of various pharmacological agents. Effect of gintonin (0, 0.3, 1, 3, 10, and 30 μg/ml) and BAPTA-AM (B), a calcium chelator, (50 μM) on acetylcholine release in the NPCs, determined using an Amplex Red Acetylcholine/Acetylcholinesterase Assay Kit (Invitrogen, #A12217). Ki16425 (Ki) also significantly attenuated gintonin-mediated acetylcholine release. NPCs were pretreated with BAPTA or Ki16425 for 1 h before gintonin treatment and then treated with gintonin or each ginsenoside for 16 h. Each value is the mean ± S.E.M. (n = 5). *P < 0.05 vs. control; #P < 0.05 or ##P < 0.01 vs. GT (3 μg/ml).
Mentions: In previous reports, we showed that gintonin derived from ginseng is a novel ligand for LPA receptors (Hwang et al., 2012a). Since LPA receptors are well expressed during the developmental stages of the brain (Hecht et al., 1996) and LPA promotes differentiation of rat embryonic neural stem cells to cholinergic neurons (Cui and Qiao, 2006), we examined the effects of gintonin on the coupling of [Ca2+]i transients to acetylcholine release using cultured hippocampal NPCs, which mainly express the LPA1 receptor (Sun et al., 2010). We first examined the effects of gintonin on [Ca2+]i transients in hippocampal NPCs. As shown in Figs. 1A and 1B, gintonin treatment induced a transient rise of [Ca2+]i in NPCs in a reversible and concentration-dependent manner. The EC50 was 0.21 ± 0.03 μg/ml. Gintonin-induced [Ca2+]i transients were initiated without a detectable lag and reached peak values within a few seconds, and [Ca2+]i gradually decreased and returned to basal level. We observed that treatment of NPC12 cells with LPA C18:1 also induced a [Ca2+]i transient, similar to gintonin (data not shown). We examined the effects of gintonin on [Ca2+]i transients in the absence or presence of the LPA1/3 receptor antagonist Ki16425. As shown in Figs. 1C and 1E, the presence of Ki16425 significantly attenuated the gintonin-mediated [Ca2+]i transient. The active phospholipase C inhibitor U73122, the inositol 1,4,5-triphosphate receptor antagonist 2-APB, and the intracellular Ca2+ chelator BAPTA-AM all blocked gintonin-mediated [Ca2+]i transients in NPCs (Figs. 1D and 1E). These results show that gintonin, via activation of the LPA receptor-phospholipase C-intracellular IP3 receptor signaling transduction pathway, elicits the release of Ca2+ from intracellular stores to increase [Ca2+]i.

Bottom Line: The brains of AD patients show a reduction in acetylcholine concentration caused by cholinergic system impairments.In this study, we used gintonin to investigate the effect of LPA receptor activation on the cholinergic system in vitro and in vivo using wild-type and AD animal models.Furthermore, this study showed that gintonin could be a novel agent for the restoration of cholinergic system damages due to Aβ and could be utilized for AD prevention or therapy.

View Article: PubMed Central - PubMed

Affiliation: Ginsentology Research Laboratory and Department of Physiology, College of Veterinary Medicine, Konkuk University, Seoul 143-701, Korea.

ABSTRACT
Gintonin is a novel ginseng-derived lysophosphatidic acid (LPA) receptor ligand. Oral administration of gintonin ameliorates learning and memory dysfunctions in Alzheimer's disease (AD) animal models. The brain cholinergic system plays a key role in cognitive functions. The brains of AD patients show a reduction in acetylcholine concentration caused by cholinergic system impairments. However, little is known about the role of LPA in the cholinergic system. In this study, we used gintonin to investigate the effect of LPA receptor activation on the cholinergic system in vitro and in vivo using wild-type and AD animal models. Gintonin induced [Ca(2+)]i transient in cultured mouse hippocampal neural progenitor cells (NPCs). Gintonin-mediated [Ca(2+)]i transients were linked to stimulation of acetylcholine release through LPA receptor activation. Oral administration of gintonin-enriched fraction (25, 50, or 100 mg/kg, 3 weeks) significantly attenuated scopolamine-induced memory impairment. Oral administration of gintonin (25 or 50 mg/kg, 2 weeks) also significantly attenuated amyloid-β protein (Aβ)-induced cholinergic dysfunctions, such as decreased acetylcholine concentration, decreased choline acetyltransferase (ChAT) activity and immunoreactivity, and increased acetylcholine esterase (AChE) activity. In a transgenic AD mouse model, long-term oral administration of gintonin (25 or 50 mg/kg, 3 months) also attenuated AD-related cholinergic impairments. In this study, we showed that activation of G protein-coupled LPA receptors by gintonin is coupled to the regulation of cholinergic functions. Furthermore, this study showed that gintonin could be a novel agent for the restoration of cholinergic system damages due to Aβ and could be utilized for AD prevention or therapy.

No MeSH data available.


Related in: MedlinePlus