Red ginseng represses hypoxia-induced cyclooxygenase-2 through sirtuin1 activation

Sirtuins in intervertebral disc degeneration: current understanding

BACKGROUND

Intervertebral disc degeneration (IVDD) is one of the etiologic factors of degenerative spinal diseases, which can lead to a variety of pathological spinal conditions such as disc herniation, spinal stenosis, and scoliosis. IVDD is a leading cause of lower back pain, the prevalence of which increases with age. Recently, Sirtuins/SIRTs and their related activators have received attention for their activity in the treatment of IVDD. In this paper, a comprehensive systematic review of the literature on the role of SIRTs and their activators on IVDD in recent years is presented. The molecular pathways involved in the regulation of IVDD by SIRTs are summarized, and the effects of SIRTs on senescence, inflammatory responses, oxidative stress, and mitochondrial dysfunction in myeloid cells are discussed with a view to suggesting possible solutions for the current treatment of IVDD.

PURPOSE

This paper focuses on the molecular mechanisms by which SIRTs and their activators act on IVDD.

METHODS

A literature search was conducted in Pubmed and Web of Science databases over a 13-year period from 2011 to 2024 for the terms "SIRT", "Sirtuin", "IVDD", "IDD", "IVD", "NP", "Intervertebral disc degeneration", "Intervertebral disc" and "Nucleus pulposus".

RESULTS

According to the results, SIRTs and a large number of activators showed positive effects against IVDD.SIRTs modulate autophagy, myeloid apoptosis, oxidative stress and extracellular matrix degradation. In addition, they attenuate inflammatory factor-induced disc damage and maintain homeostasis during disc degeneration. Several clinical studies have reported the protective effects of some SIRTs activators (e.g., resveratrol, melatonin, honokiol, and 1,4-dihydropyridine) against IVDD.

CONCLUSION

The fact that SIRTs and their activators play a hundred different roles in IVDD helps to better understand their potential to develop further treatments for IVDD.

NOVELTY

This review summarizes current information on the mechanisms of action of SIRTs in IVDD and the challenges and limitations of translating their basic research into therapy.

Avenanthramide C suppresses hypoxia-induced cyclooxygenase-2 expression through sirtuin1 activation in non-small-cell lung cancer cells

Avenanthramide C (AVC), found mainly in oats, mediates anti-inflammatory activities by reducing the anti-inflammatory cytokine levels. This study investigated the effects of AVC on hypoxia-induced cyclooxygenase-2 (COX-2) expression in A549 cells. AVC suppressed the hypoxia-induced increase in COX-2 protein levels and promoter activity. We also observed that the effects of AVC were reversed by a SIRT1 inhibitor, indicating that the inhibitory effects of AVC on hypoxia-induced COX-2 expression are mediated by SIRT1. Therefore, AVC inhibits the hypoxic induction of COX-2 expression via SIRT1 activation. Our results suggest that AVC could be beneficial for preventing lung inflammation under hypoxia.

How Ginsenosides Trigger Apoptosis in Human Lung Adenocarcinoma Cells

Panax ginseng is a natural medicine that has been used globally for a long time. Moreover, several studies have reported the effective activity of ginseng in treating malignancies. Various agents containing ginseng were widely used as an antitumor treatment nowadays. Lung cancer is the most common fatal cancer in China, and lung adenocarcinoma is the most common histological type of non-small cell lung cancer (NSCLC). What's worse, many patients may have a failed response to conventional therapy including chemotherapy, radiotherapy, or molecule-targeted therapy due to drug resistance. Apoptosis is a highly ordered cellular suicidal process that plays an essential role in maintaining normal homeostasis. The pharmacological mechanism of many antineoplastic drugs involves triggering of apoptotic process. In several recent studies, ginsenosides are regarded as major active components of ginseng that have the potential to control lung cancer. Most of these results have proved that ginsenosides induce apoptosis in lung cancer cells through many different signaling pathways such as PI3K/Akt, NF-κB, EGFR, and so on. This study is aimed at reviewing the signaling pathways that underlie ginsenosides-triggered apoptotic process and encourage further studies to target promising agents against lung cancer treatment.

Extension of Drosophila lifespan by Korean red ginseng through a mechanism dependent on dSir2 and insulin/IGF-1 signaling

Many studies have indicated that Korean red ginseng (KRG) has anti-inflammatory and anti-oxidative effects, thereby inducing many health benefits in humans. Studies into the longevity effects of KRG are limited and have provided contradictory results, and the molecular mechanism of lifespan extension by KRG is not elucidated yet. Herein, the longevity effect of KRG was investigated in Drosophila melanogaster by feeding KRG extracts, and the molecular mechanism of lifespan extension was elucidated by using longevity-related mutant flies. KRG extended the lifespan of Drosophila when administrated at 10 and 25 μg/mL, and the longevity benefit of KRG was not due to reduced feeding, reproduction, and/or climbing ability in fruit flies, indicating that the longevity benefit of KRG is a direct effect of KRG, not of a secondary artifact. Diet supplementation with KRG increased the lifespan of flies on a full-fed diet but not of those on a restricted diet, and the longevity effect of KRG was diminished by the mutation of dSir2, a deacetylase known to mediate the benefits of dietary restriction. Similarly, the longevity effect of KRG was mediated by the reduction of insulin/IGF-1 signaling. In conclusion, KRG extends the lifespan of Drosophila through Sir2 and insulin/IGF-1 signaling and has potential as an anti-aging dietary-restriction mimetic and prolongevity supplement.

UDP and NTF2 are the most consistently expressed genes in Panax ginseng roots at different growth stages

Reverse transcription‑quantitative polymerase chain reaction (RT‑qPCR) analysis relies on normalization against a consistently expressed reference gene. However, it has been reported that reference gene expression levels often vary markedly between samples as they are usually selected based solely on convention. The advent of RNA sequencing technology offers the opportunity to select reference genes with the least variability in steady‑state transcript levels. To identify the most consistently stable genes, which are a prerequisite for obtaining reliable gene expression data, the present study analyzed transcriptomes from six Panax ginseng transcriptome data sets, representing six growth stages, and selected 21 candidate reference genes for screening using RT‑qPCR. Of the 21 candidate genes, 13 had not been reported previously. The geNorm, NormFinder and BestKeeper programs were used to analyze the stability of the 21 candidate reference genes. The results showed that UDP‑N‑acetylgalactosamine transporter and nuclear transport factor 2 were likely to be the optimal combination of reference genes for use in investigations of ginseng. The novel reference genes were validated by correlating the gene expression profiles of four pathogenesis‑related protein genes generated from RT‑qPCR, with their expression levels calculated from the RNA sequencing data. The expression levels were well correlated, which demonstrated their value in performing RT‑qPCR analyses in ginseng.

Inhibition of hypoxia-induced cyclooxygenase-2 by Korean Red Ginseng is dependent on peroxisome proliferator-activated receptor gamma

Background

Korean Red Ginseng (KRG) is a traditional herbal medicine made by steaming and drying fresh ginseng. It strengthens the endocrine and immune systems to ameliorate various inflammatory responses. The cyclooxygenase-2 (COX-2)/prostaglandin E2 pathway has important implications for inflammation responses and tumorigenesis. Peroxisome proliferator-activated receptor gamma (PPARγ) is a transcription factor that regulates not only adipogenesis and lipid homeostasis, but also angiogenesis and inflammatory responses.

Methods

The effects of the KRG on inhibition of hypoxia-induced COX-2 via PPARγ in A549 cells were determined by luciferase assay, Western blot, and/or quantitative reverse transcription-polymerase chain reaction (qRT-PCR). The antimigration and invasive effects of KRG were evaluated on A549 cells using migration and matrigel invasion assays.

Results and conclusion

We previously reported that hypoxia-induced COX-2 protein and mRNA levels were suppressed by KRG. This study examines the possibility of PPARγ as a cellular target of KRG for the suppression of hypoxia-induced COX-2. PPARγ protein levels and PPARγ-responsive element (PPRE)-driven reporter activities were increased by KRG. Reduction of hypoxia-induced COX-2 by KRG was abolished by the PPARγ inhibitor GW9662. In addition, the inhibition of PPARγ abolished the effect of KRG on hypoxia-induced cell migration and invasion.

Discussion

Our results show that KRG inhibition of hypoxia-induced COX-2 expression and cell invasion is dependent on PPARγ activation, supporting the therapeutic potential for suppression of inflammation under hypoxia. Further studies are required to demonstrate whether KRG activates directly PPARγ and to identify the constituents responsible for this activity.

Methyl syringate, a TRPA1 agonist represses hypoxia-induced cyclooxygenase-2 in lung cancer cells

BACKGROUND

We have previously found that methyl syringate is a specific and selective agonist of the human transient receptor potential channel ankyrin 1 (TRPA1) and suppresses food intake and gastric emptying in imprinting control region mice. Because TRPA1 has been implicated in inflammatory responses, and inflammation and tumorigenesis are stimulated by the cyclooxygenase-2 (COX-2)/prostaglandin E2 pathway in hypoxic cancer cells.

PURPOSE

This study examined the effects of methyl syringate on hypoxia-induced COX-2 in human distal lung epithelial A549 cells.

STUDY DESIGN

The effect of the methyl syringate on suppression of hypoxia-induced COX-2 in A549 cells were determined by Western blot and/or quantitative real-time polymerase chain reaction. The anti-invasive effect of methyl syringate was evaluated on A549 cells using matrigel invasion assay.

RESULTS

Methyl syringate suppressed hypoxia-induced COX-2 protein and mRNA expression and promoter activity and reduced hypoxia-induced cell migration and invasion and secretion of vascular endothelial growth factor. These effects were antagonized by a TRPA1 antagonist, implying their mediation by the TRPA1 pathway.

CONCLUSION

Together, these results indicate that methyl syringate inhibits the hypoxic induction of COX-2 expression and cell invasion through TRPA1 activation. These findings suggest that methyl syringate could be effective to suppress hypoxia-induced inflammation and indicate an additional functional effect of methyl syringate.