• International Journal of Oral Biology
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• 제31권3호
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• pp.87-92
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• 2006

Schwann cells play an important role in peripheral nerve regeneration. Upon nerve injury, Schwann cells are activated and produce various proinflammatory mediators including IL-6, LIF and MCP-1, which result in the recruitment of macrophages and phagocytosis of myelin debris. However, it is unclear how the nerve injury induces Schwann cell activation. Recently, it was reported that necrotic cells induce immune cell activation via toll-like receptors (TLRs). This suggests that the TLRs expressed on Schwann cells may recognize nerve damage by binding to the endogenous ligands secreted by the damaged nerve, thereby inducing Schwann cell activation. To explore the possibility, we stimulated iSC, a rat Schwann cell line, with damaged neuronal cell extracts (DNCE). The stimulation of iSC with DNCE induced the expression of various inflammatory mediators including IL-6, LIF, MCP-1 and iNOS. Studies on the signaling pathway indicate that $NF-{\kappa}B$, p38 and JNK activation are required for the DNCE-induced inflammatory gene expression. Furthermore, treatment of either anti-TLR3 neutralizing antibody or ribonuclease inhibited the DNCE-induced proinflammatory gene expression in iSC. In summary, these results suggest that damaged neuronal cells induce inflammatory Schwann cell activation via TLR3, which might be involved in the Wallerian degeneration after a peripheral nerve injury.

• BMB Reports
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• 제45권9호
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• pp.489-495
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• 2012

Ischemia is a blockage of blood supply due to an embolism or a hemorrhage in a blood vessel. When an organ cannot receive oxygenated blood and can therefore no longer replenish its blood supply due to ischemia, stresses, such as the disruption of blood glucose homeostasis, hypoglycemia and hypoxia, activate the AMPK complex. LKB1 and $CaMKK{\beta}$ are essential activators of the AMPK signaling pathway. AMPK triggers proangiogenic effects through the eNOS protein in tissues with ischemic conditions, where cells are vulnerable to apoptosis, autophagy and necrosis. The AMPK complex acts to restore blood glucose levels and ATP levels back to homeostasis. This review will discuss AMPK, as well as its key activators (LKB1 and $CaMKK{\beta}$), as a central energy regulator and evaluate the upstream and downstream regulating pathways of AMPK. We will also discuss how we can control this important enzyme in ischemic conditions to prevent harmful effects in patients with vascular damage.

• 대한수의학회지
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• 제43권3호
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• pp.485-492
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• 2003

The pathological mechanism of impaired spermatogenesis after vasectomy has not been completely investigated. In this study, we examined pathological changes of the testis and the Fas-Fas ligand (FasL) mediated signaling pathway in apoptotic germ cell death after vasectomy in rats. Ten-weeks old Sprague-Dawley rats were underwent bilateral vasectomy and sacrificed after 1 day, 2 days, 3 days, 5 days, 1 week, 2 weeks, and 4 weeks of surgery and the testes were removed. Histopathological evaluation of spermatogenesis was performed by hematoxylin-eosin and periodic acid-Schiff-hematoxylin staining. To elucidate the pathophysiology of seminiferous tubule damage, terminal dUTP nick end labeling staining, electrophoresis assay of DNA fragmentation, and Western blotting analysis for Fas-FasL were performed. Relative weights of testes were decreased from 5 days after vasectomy. Germ cell degeneration were first found in the spermatogonia and spermatocytes at stages I-VI, and XII-XIV seminiferous tubules. Mean incidence of apoptotic germ cells after vasectomy progressively increased to peak in 5 days, and then gradually decreased to the control levels in 2 weeks after vasectomy. The expression of Fas-FasL reached maximum level at 5 days after vasectomy and then declined. In conclusion, impaired spermatogenesis after vasectomy associated with an increase in germ cell apoptasis, which is partly mediated by the activation of Fas-FasL.

• 한국임상수의학회지
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• 제21권3호
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• pp.253-258
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• 2004

DNA double-strand break (DSB) is a serious treat for the cells including mutations, chromosome rearrangements, and even cell death if not repaired or misrepaired. Ku heterodimer regulatory DNA binding subunits (Ku70/Ku80) bound to double strand DNA breaks are able to interact with 470-kDa DNA-dependent protein kinase catalytic subunit (DNA-PKcs), and the interaction is essential for DNA-dependent protein kinase (DNA-PK) activity. The Ku80 mutants were designed to bind Ku70 but not DNA end binding activity and the peptides were treated in breast cancer cells for co-therapy strategy to see whether the targeted inhibition of DNA-dependent protein kinase (DNA-PK) activity sensitized breast cancer cells to ionizing irradiation or chemotherapy drug to develop a treatment of breast tumors by targeting proteins involved in damage-signaling pathway and/or DNA repair. We designed domains of Ku80 mutants, 26 residues of amino acids (HN-26) as a control peptide or 38 (HNI-38) residues of amino acids which contain domains of the membrane-translocation hydrophobic signal sequence and the nuclear localization sequence, but HNI-38 has additional twelve residues of peptide inhibitor region. We observed that the synthesized peptide (HNI-38) prevented DNA-PKcs from binding to Ku70/Ku80, resulting in inactivation of DNA-PK complex activity in breast cancer cells (MDA-465 and MDA-468). Consequently, the peptide treated cells exhibited poor to no DNA repair, and became highly sensitive to irradiation or chemotherapy drugs. The growth of breast cancer cells was also inhibited. These results demonstrate the possibility of synthetic peptide to apply breast cancer therapy to induce apoptosis of cancer cells.

• 대한한의학회지
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• 제22권4호
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• pp.58-68
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• 2001

Objectives : This study was designed to investigate the protective mechanisms of Samul-tang (SMT) on $H_2O_2$-induced toxicity in H9c2 cardiomyoblast cells. Methods : The cultured cells were pretreated with SMT and exposed to $H_2O_2$. The cell damage was assessed by using MTT assay. Also, we used Hoechst staining, Western blotting analysis. Results : SMT significantly reduced both $H_2O_2$-induced cell death and chromatin fragmentation. The decrease of Bcl2 expression by $H_2O_2$ was inhibited by SMT. In addition, the increase of Bax expression was also inhibited by SMT. In particular, Fas expression, which is generally recognized as cell death inducing signal by Fas/FasL interaction, was markedly decreased by $H_2O_2$ in a time-dependent manner, whereas this decrease was completely prevented by SMT. The cotreatment of SMT and $H_2O_2$ in H9c2 cells also induced the phosphorylation of ERK in a time-dependent manner. Moreover, PD098059, a specific inhibitor of ERKl/2, attenuated the protective effect of SMT on $H_2O_2$-induced toxicity in H9c2 cardiomyoblast cells. Furthermore, the protective effect of SMT was significantly blocked by treatment of SB203580, a specific inhibitor of p38. Conclusions : Taken together, this study suggests that the protective effects of the water extract of SMT against oxidative damages may be mediated by the modulation of Bel2 and Bax expression via the regulation of ERK and p38 signaling pathway.

• KSBB Journal
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• 제29권1호
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• pp.50-57
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• 2014

NF-${\kappa}B$ is a transcriptional factor which is involved in many biological processes including immunity, inflammation, and cell survival. Many investigators studied on the mechanism involved in activation of NF-${\kappa}B$ signalling pathway via ubiquitination and degradation of $I{\kappa}B$ regarding skin disease. Some specific molecules including Akt, MEK, p38 MAP Kinase, Stat3, et al. represent convergence points and key regulatory proteins in signaling pathways controlling cellular events such as growth and differentiation, energy homeostasis, and the response to stress and inflammation. Ultraviolet (UV) irradiation has many adverse effects on skin, including inflammation, alteration in the extracellular matrix, cellular senescence, apoptosis and skin cancer. Prunus mume, a naturally derived plant extract, has beneficial biological activities as blood fluidity improvement, anti-fatigue action, antioxidative and free radical scavenging activities, inhibiting the motility of Helicobacter pyolri. Previous reports on various beneficial function prompted us to investigate UVB-induced or other immunostimulated biological marker regarding P. mume extract. P. mume extract suppresses UVB-induced cyclooxygenase-2 (COX-2) expression in mouse skin epidermal JB6 P+ cells. The activation of activator protein-1 and nuclear factor-${\kappa}B$ induced by UVB was dose-dependently inhibited by P. mume extract treatment. This results suggest that P. mume extracts might be used as a potential agents for protection of inflammation or UVB induced skin damage.

• IMMUNE NETWORK
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• 제11권6호
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• pp.376-382
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• 2011

Background: Carbon monoxide (CO) is a cytoprotective and homeostatic molecule with important signaling capabilities in physiological and pathophysiological situations. CO protects cells/tissues from damage by free radicals or oxidative stress. NAD(P)H:quinone oxidoreductase (NQO1) is a highly inducible enzyme that is regulated by the Kelch-like ECH-associated protein 1 (Keap1)/nuclear factor erythroid 2-related factor 2 (Nrf2)/antioxidant response element (ARE) pathway, which is central to efficient detoxification of reactive metabolites and reactive oxygen species (ROS). Methods: We generated NQO1 promoter construct. HepG2 cells were treated with CO Releasing Molecules-2 (CORM-2) or CO gas and the gene expressions were measured by RT-PCR, immunoblot, and luciferase assays. Results: CO induced expression of NQO1 in human hepatocarcinoma cell lines by activation of Nrf2. Exposure of HepG2 cells to CO resulted in significant induction of NQO1 in dose- and time-dependent manners. Analysis of the NQO1 promoter indicated that an antioxidant responsible element (ARE)-containing region was critical for the CO-induced Nrf2-dependent increase of NQO1 gene expression in HepG2 cells. Conclusion: Our results suggest that CO-induced Nrf2 increases the expression of NQO1 which is well known to detoxify reactive metabolites and ROS.

• The Korean Journal of Physiology and Pharmacology
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• 제24권6호
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• pp.473-479
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• 2020

Endothelial cell injury is a major contributor to cardiovascular diseases. The 2,3,5,4'-Tetrahydroxystilbene-2-O-β-D-Glucoside (TSG) contributes to alleviate human umbilical vein endothelial cells (HUVECs) injury through mechanisms still know a little. This study aims to clarify the TSG effects on gene expression (mRNA and microRNA) related to oxidative stress and endoplasmic reticulum stress induced by H₂O₂ in HUVECs. We found that TSG significantly reduced the death rate of cells and increased intracellular superoxide dismutase activity. At qRT-PCR, experimental data showed that TSG significantly counteracted the expressions of miR-9-5p, miR-16, miR-21, miR-29b, miR-145-5p, and miR-204-5p. Besides, TSG prevented the expression of ATF6 and CHOP increasing. In contrast, TSG promoted the expression of E2F1. In conclusion, our results point to the obvious protective effect of TSG on HUVECs injury induced by H₂O₂, and the mechanism may through miR16/ATF6/ E2F1 signaling pathway.

• Journal of Ginseng Research
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• 제46권2호
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• pp.266-274
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• 2022

Colon cancer, the third most frequent occurred cancer, has high mortality and extremely poor prognosis. Ginsenoside, the active components of traditional Chinese herbal medicine Panax ginseng, exerts antitumor effect in various cancers, including colon cancer. However, the detailed molecular mechanism of Ginsenoside in the tumor suppression have not been fully elucidated. Here, we chose the representative ginsenoside Rg3 and reported for the first time that Rg3 induces mitophagy in human colon cancer cells, which is responsible for its anticancer effect. Rg3 treatment leads to mitochondria damage and the formation of mitophagosome; when autophagy is inhibited, the clearance of damaged mitochondria can be reversed. Next, our results showed that Rg3 treatment activates the PINK1-Parkin signaling pathway and recruits Parkin and ubiquitin proteins to mitochondria to induce mitophagy. GO analysis of Parkin targets showed that Parkin interacts with a large number of mitochondrial proteins and regulates the molecular function of mitochondria. The cellular energy metabolism enzyme GAPDH is validated as a novel substrate of Parkin, which is ubiquitinated by Parkin. Moreover, GAPDH participates in the Rg3-induced mitophagy and regulates the translocation of Parkin to mitochondria. Functionally, Rg3 exerts the inhibitory effect through regulating the nonglycolytic activity of GAPDH, which could be associated with the cellular oxidative stress. Thus, our results revealed GAPDH ubiquitination by Parkin as a crucial mechanism for mitophagy induction that contributes to the tumor-suppressive function of ginsenoside, which could be a novel treatment strategy for colon cancer.

• Genomics & Informatics
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• 제20권3호
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• pp.26.1-26.19
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• 2022

Diabetes and its related complications are associated with long term damage and failure of various organ systems. The microvascular complications of diabetes considered in this study are diabetic retinopathy, diabetic neuropathy, and diabetic nephropathy. The aim is to identify the weighted co-expressed and differentially expressed genes (DEGs), major pathways, and their miRNA, transcription factors (TFs) and drugs interacting in all the three conditions. The primary goal is to identify vital DEGs in all the three conditions. The overlapped five genes (AKT1, NFKB1, MAPK3, PDPK1, and TNF) from the DEGs and the co-expressed genes were defined as key genes, which differentially expressed in all the three cases. Then the protein-protein interaction network and gene set linkage analysis (GSLA) of key genes was performed. GSLA, gene ontology, and pathway enrichment analysis of the key genes elucidates nine major pathways in diabetes. Subsequently, we constructed the miRNA-gene and transcription factor-gene regulatory network of the five gene of interest in the nine major pathways were studied. hsa-mir-34a-5p, a major miRNA that interacted with all the five genes. RELA, FOXO3, PDX1, and SREBF1 were the TFs interacting with the major five gene of interest. Finally, drug-gene interaction network elucidates five potential drugs to treat the genes of interest. This research reveals biomarker genes, miRNA, TFs, and therapeutic drugs in the key signaling pathways, which may help us, understand the processes of all three secondary microvascular problems and aid in disease detection and management.