NF-κB signaling pathway inhibition suppresses hippocampal neuronal apoptosis and cognitive impairment via RCAN1 in neonatal rats with hypoxic-ischemic brain damage

Abstract Lepidium meyenii (Maca) is an annual or biennial herb from South America that is a member of the genus Lepidium L. in the family Cruciferae. This herb has antioxidant, anti-apoptotic, and enhances autophagy functions and can prevent cell death, and protect neurons from ischemic damage. Macamide B, an effective active ingredient of maca, has a neuroprotective role in neonatal hypoxic-ischemic brain damage (HIBD), and the underlying mechanism of its neuroprotective effect is not yet known. The purpose of this study is to explore the impact of macamide B on HIBD-induced autophagy and apoptosis and its potential mechanism for neuroprotection. The modified Rice-Vannucci method was used to induce HIBD on 7-day-old (P7) macamide B and vehicle-pretreated pups. TTC staining was used to evaluate the cerebral infarct volume of pups, brain water content was measured to evaluate the neurological function of pups, neurobehavioral testing was used to assess functional recovery after HIBD, TUNEL and FJC staining was used to detect cell autophagy and apoptosis, and western blot analysis was used to detect the expression levels of the pro-survival signaling pathway phosphatidylinositol-3-kinase/protein kinase B (PI3K/AKT) and autophagy and the apoptosis-related proteins. The results show that macamide B pretreatment can significantly decrease brain damage, improve the recovery of neural function after HIBD. At the same time, macamide B pretreatment can induce the activation of PI3K/AKT signaling pathway after HIBD, enhance autophagy, and reduce hypoxic-ischemic (HI)-induced apoptosis. In addition, 3-methyladenine (3-MA), an inhibitor of PI3K/AKT signaling pathway, significantly inhibits the increase in autophagy levels, aggravates HI-induced apoptosis, and reverses the neuroprotective effect of macamide B on HIBD. Our data indicate that macamide B pretreatment might regulate autophagy through PI3K/AKT signaling pathway, thereby reducing HIBD-induced apoptosis and exerting neuroprotective effects on neonatal HIBD. Macamide B may become a new drug for the prevention and treatment of HIBD.

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Effects of MicroRNA-592-5p on Hippocampal Neuron Injury Following Hypoxic-Ischemic Brain Damage in Neonatal Mice - Involvement of PGD2/DP and PTGDR

Cellular Physiology and Biochemistry ◽

10.1159/000486923 ◽

2018 ◽

Vol 45 (2) ◽

pp. 458-473 ◽

Cited By ~ 9

Author(s):

Li-Qun Sun ◽

Gong-Liang Guo ◽

Sai Zhang ◽

Li-Li Yang

Keyword(s):

Cell Cycle ◽

Mouse Model ◽

Signaling Pathway ◽

Brain Damage ◽

Target Gene ◽

Ischemic Brain Damage ◽

Ischemic Brain ◽

Expression Levels ◽

Neonatal Mice ◽

Group A

Background/Aims: This study aimed to explore the effect of microRNA-592-5p (miR-592-5p) on hypoxic-ischemic brain damage (HIBD)-induced hippocampal neuronal injury in a neonatal mouse model relative to the involvement of one target gene, PTGDR, and the PGD2/ DP signaling pathway. Methods: A total of 30 neonatal mice aged 7 days were randomly selected to establish an HIBD mouse model. Hippocampal neuronal cells were transfected into a control group, a blank group, a negative control (NC) group, an miR-592-5p mimics group, an miR-592-5p inhibitors group, an siRNA-PTGDR group and an miR-592-5p inhibitors + siRNA-PTGDR group. Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and Western blot analyses were performed to detect the expression levels of miR-592-5p, PTGDR, DP2, Bcl-2 and Bax in tissues and cells. Cell proliferation, cell cycle and apoptosis were detected by MTT assay and flow cytometry, respectively. Results: The expression levels of miR-592-5p and Bcl-2 decreased, while the expression levels of PTGDR, DP2 and Bax increased in the HIBD group. PTGDR is a target gene of miR-592-2p. Compared with the NC and blank groups, the expression levels of PTGDR, DP2 and Bax decreased, while the expression levels of miR-592-5p and Bcl-2 increased in the miR-592-5p mimics group. The siRNA-PTGDR group showed the same trend as that observed in the miR-592-5p mimics group, except with no difference in miR-592-5p expression. The miR-592-5p inhibitors group showed an opposite gene expression trend compared to that in the miR-592-5p mimics group. The S phase of the cell cycle was prolonged, the G1 phase was reduced, proliferation was increased, and the apoptosis rate was decreased in the siRNA-PTGDR and miR-592-5p mimics groups. Opposite trends for cell cycle, proliferation and apoptosis were observed in the miR-592-5p inhibitors group. Conclusions: Our study suggests that miR-592-5p upregulation protects against hippocampal neuronal injury caused by HIBD by targeting PTGDR and inhibiting the PGD2/DP signaling pathway.

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