Effects of gintonin-enriched fraction on hippocampal gene expressions

Rami Lee; Na-Eun Lee; Sun-Hye Choi; Sung Min Nam; Hyoung-Chun Kim; Hyewhon Rhim; Ik-Hyun Cho; Sung-Hee Hwang; Seung-Yeol Nah

doi:10.1016/j.imr.2020.100475

Effects of gintonin-enriched fraction on hippocampal gene expressions

Integr Med Res. 2021 Jun;10(2):100475. doi: 10.1016/j.imr.2020.100475. Epub 2020 Jul 15.

Authors

Rami Lee¹, Na-Eun Lee¹, Sun-Hye Choi¹, Sung Min Nam¹, Hyoung-Chun Kim², Hyewhon Rhim³, Ik-Hyun Cho⁴, Sung-Hee Hwang⁵, Seung-Yeol Nah¹

Affiliations

¹ Ginsentology Research Laboratory and Department of Physiology, College of Veterinary Medicine, Konkuk University, Seoul, Republic of Korea.
² Neuro Psychopharmacology and Toxicology Program, College of Pharmacy, Kangwon National University, Chunchon, Republic of Korea.
³ Center for Neuroscience, Korea Institute of Science and Technology, Seoul, Republic of Korea.
⁴ Department of Convergence Medical Science, Department of Science in Korean Medicine and Brain Korea 21 Plus Program, Graduate School, Kyung Hee University, Seoul, Republic of Korea.
⁵ Department of Pharmaceutical Engineering, College of Health Sciences, Sangji University, Wonju, Republic of Korea.

Abstract

Background: Recently, gintonin and gintonin-enriched fraction (GEF) have been isolated from ginseng, a herbal medicine. Gintonin induces [Ca²⁺]_i transition in cultured hippocampal neurons and stimulates acetylcholine release through LPA receptor activation. Oral administration of GEF is linked to hippocampus-dependent cognitive enhancement and other neuroprotective effects; however, effects of its long-term administration on hippocampal gene expression remains unknown. Here, we used next-generation sequence (NGS) analysis to examine changes in hippocampal gene expressions after long-term oral administration of GEF.

Methods: C57BL/6 mice were divided into three groups: control group, GEF50 (GEF 50 mg/kg, p.o.), and GEF100 (GEF 100 mg/kg, p.o.). After 22 days, total RNA was extracted from mouse hippocampal tissues. NGS was used for gene expression profiling; quantitative-real-time PCR and western blot were performed to quantify the changes in specific genes and to confirm the protein expression levels in treatment groups.

Results: NGS analysis screened a total of 23,282 genes, analyzing 11-related categories. We focused on the neurogenesis category, which includes four genes for candidate markers: choline acetyltransferase (ChAT) gene, β₃-adrenergic receptor (Adrb3) gene, and corticotrophin-releasing hormone (Crh) gene, and tryptophan 2,3-dioxygenase (Tdo2) gene. Real-time PCR showed a marked overexpression of ChAT, Adrb3, and Crh genes, while reduced expression of Tdo2. Western blot analysis also confirmed increased ChAT and decreased Tdo2 protein levels.

Conclusion: We found that GEF affects mouse hippocampal gene expressions, associated with memory, cognitive, anti-stress and anti-anxiety functions, and neurodegeneration at differential degree, that might explain the genetic bases of GEF-mediated neuroprotective effects.

Keywords: Cognition; Ginseng; Gintonin; Hippocampus gene; NGS analysis.