Carthamus tinctorius L. Seed and Taraxacum coreanum Attenuate Oxidative Stress Induced by Hydrogen Peroxide in SH-SY5Y Cells.

Oxidative stress is closely associated with the pathology of neurodegenerative diseases. The seeds of Carthamus tinctorius L. (CTS) and Taraxacum coreanum (TC) are reported as herbal medicines for neuroprotection. This study investigated the protective effect of CTS, TC, and their combination against oxidative stress induced by H2O2 in SH-SY5Y cells. The CTS and TC combination dose-dependently increased DPPH and ·OH radical scavenging activities compared with non-combination. The combination showed a higher increased cell survival rate in H2O2-stimulated SH-SY5Y cells than CTS or TC. Moreover, CTS, TC, and their combination-treated cells reduced LDH release and apoptotic cells. CTS, TC, and their combination also inhibited NO and ROS generation. Further, the combination of up-regulated antioxidant enzymes (superoxide dismutase and glutathione peroxidase) and Bcl-2 protein expressions and down-regulated Bax expression. These findings suggest that the combination of CTS and TC may be beneficial to prevent and treat oxidative stress-mediated neurodegenerative diseases.

Safflower Seed Extract Attenuates the Development of Osteoarthritis by Blocking NF-κB Signaling.

Although safflower seed extract exhibits pharmacological activity against various diseases, the effects of its individual compounds on osteoarthritis (OA) have not been elucidated. Here, we evaluated the effects of these extracts and their single compounds on OA. N-(p-Coumaroyl) serotonin and N-feruloyl serotonin, main components of safflower seed extract, were isolated by high-performance liquid chromatography. Under in vitro OA mimic conditions, the expression of the matrix metalloproteinases (MMPs) MMP3/13 and a disintegrin and metalloproteinase with thrombospondin motifs (ADAMTS) ADAMTS5 were reduced in mouse chondrocytes treated with safflower seed extract. Furthermore, the oral administration of safflower seed extract attenuated cartilage destruction in a mouse OA model induced by destabilization of the medial meniscus. N-(p-Coumaroyl) serotonin and N-feruloyl serotonin, but not serotonin, reduced MMP3, MMP13, and ADAMTS5 expression in IL-1ß-treated chondrocytes. Additionally, they significantly blocked the nuclear factor-κB (NF-κB) pathway by inhibiting IκB degradation and p65 phosphorylation. Our results suggest that safflower seed extract and its single compounds can attenuate cartilage destruction by suppressing MMP and ADMATS5 expression. The anti-arthritic effects are mediated by NF-κB signaling and involve the inhibition of IκB degradation and p65 phosphorylation. These results indicate that safflower seed extract may serve as a novel therapeutic agent against OA.

Extracts of Perilla frutescens var. Acuta (Odash.) Kudo Leaves Have Antitumor Effects on Breast Cancer Cells by Suppressing YAP Activity.

Yes-associated protein (YAP)/WW domain-containing transcription factor (TAZ) is critical for cell proliferation, survival, and self-renewal. It has been shown to play a crucial oncogenic role in many different types of tumors. In this study, we investigated the antitumor effect of the extracts of Perilla frutescens var. acuta (Odash.) Kudo leaves (PLE) on Hippo-YAP/TAZ signaling. PLE induced the phosphorylation of YAP/TAZ, thereby inhibiting their activity. In addition, the treatment suppresses YAP/TAZ transcriptional activity via the dissociation of the YAP/TAZ-TEAD complex. To elucidate the molecular mechanism of PLE in the regulation of YAP activity, we treated WT and cell lines with gene knockout (KO) for Hippo pathway components with PLE. The inhibitory effects of PLE on YAP-TEAD target genes were significantly attenuated in LATS1/2 KO cells. Moreover, we found the antitumor effect of PLE on MDA-MB-231 and BT549, both of which are triple-negative breast cancer (TNBC) cell lines. PLE reduced the viability of TNBC cells in a dose-dependent manner and induced cell apoptosis. Further, PLE inhibited the migration ability in MDA-MB-231 cells. This ability was weakened in YAP and TEAD-activated clones suggesting that the inhibition of migration by PLE is mainly achieved by regulating YAP activity. Taken together, the results of this study indicate that PLE suppressed cell growth and increased the apoptosis of breast cancer (BC) cells via inactivation of YAP activity in a LATS1/2-dependent manner.

Seomae mugwort and jaceosidin attenuate osteoarthritic cartilage damage by blocking IκB degradation in mice.

Seomae mugwort, a Korean native variety of Artemisia argyi, exhibits physiological effects against various diseases. However, its effects on osteoarthritis (OA) are unclear. In this study, a Seomae mugwort extract prevented cartilage destruction in an OA mouse model. In vitro and ex vivo analyses revealed that the extract suppressed MMP3, MMP13, ADAMTS4 and ADAMTS5 expression induced by IL-1ß, IL-6 and TNF-α and inhibited the loss of extracellular sulphated proteoglycans. In vivo analysis revealed that oral administration of the extract suppressed DMM-induced cartilage destruction. We identified jaceosidin in Seomae mugwort and showed that this compound decreased MMP3, MMP13, ADAMTS4 and ADAMTS5 expression levels, similar to the action of the Seomae mugwort extract in cultured chondrocytes. Interestingly, jaceosidin and eupatilin combined had similar effects to Seomae mugwort in the DMM-induced OA model. Induction of IκB degradation by IL-1ß was blocked by the extract and jaceosidin, whereas JNK phosphorylation was only suppressed by the extract. These results suggest that the Seomae mugwort extract and jaceosidin can attenuate cartilage destruction by suppressing MMPs, ADAMTS4/5 and the nuclear factor-κB signalling pathway by blocking IκB degradation. Thus, the findings support the potential application of Seomae mugwort, and particularly jaceosidin, as natural therapeutics for OA.

Caterpillar Medicinal Mushroom, Cordyceps militaris (Ascomycetes), Protects Aß1-42-Induced Neurologic Damage in C6 Glial Cells.

Alzheimer's disease (AD) shows neurological symptoms common to cognitive disorders and memory loss. Several hypotheses have suggested that the accumulation of amyloid-beta peptide (Aß) and reduction of acetylcholine synthesis cause AD. Natural ingredients, such as Cordyceps militaris, have been widely used for AD treatment. Herein, we investigated the protective role of C. militaris against neural dysfunction. First, Aß1-42 peptide solution was incubated at 37°C for 3 days for aggregation. Next, C6 glial cells were treated with 25 µM of Aß1-42 solution, followed by the addition of C. militaris ethanol extract (0.5, 1, 1.25, and 2.5 µg/mL); the cell viability, reactive oxygen species (ROS) production, and protein expressions were then evaluated. Reduction of viability of, and ROS generation in, Aß1-42-treated cells were observed and compared with those in the control group. The expression levels of inducible nitric oxide synthase and cyclooxygenase-2, as well as those of phospho-p38 mitogen-activated protein kinase and phospho-c-Jun N-terminal kinase, were reduced in C. militaris-treated glial cells. Moreover, the expression of brain-derived neurotrophic factor in the C. militaris-treated cells was significantly higher than that in the control group. Thus, our findings indicate that C. militaris has the potential to protect Aß-induced neurological damage.

Quercetin Synergistically Inhibit EBV-Associated Gastric Carcinoma with Ganoderma lucidum Extracts.

Mycotherapy has been shown to improve the overall response rate during cancer treatment and reduce some chemotherapy-related adverse events. Ganoderma lucidum is a traditional mushroom used for pharmaceutical purposes. G. lucidum extracts (GLE) showed potential antitumor activities against several cancers. These tumor inhibitory effects of GLE were attributed to the suppression of the proliferation and metastasis of cancer cells. Epstein-Barr virus (EBV)-associated gastric carcinoma (EBVaGC) is defined as the monoclonal proliferation of carcinoma cells with latent EBV infection. The inhibitory effects of GLE against EBVaGC are questionable. The aim of this study was to investigate GLE as potential antitumor agents and a counterpart of quercetin (QCT) for the cotreatment in suppressing EBVaGC development. Therefore, this study conducted antitumor assays using a EBVaGC xenograft mice model and found that GLE could suppress tumor development. These inhibitory effects were significantly augmented by the low concentration of the quercetin (QCT) cotreatment in the xenograft mice. The addition of GLE in low concentrations synergistically reinforced QCT-induced apoptosis and EBV lytic reactivation. GLE contains various polysaccharides and triterpenes, such as ganoderic acid. Interestingly, the addition of ganoderic acid A (GAA) could produce similar bioactive effects like GLE in QCT-mediated antitumor activity. The GAA addition in low concentrations synergistically reinforced QCT-induced apoptosis and EBV lytic reactivation. GAA was sufficiently effective as much as GLE. Therefore, our results suggested that QCT-supplemented GLE could be a potential food adjunct for the prevention of EBVaGC development.

Safflower (Carthamus tinctorius L.) seed attenuates memory impairment induced by scopolamine in mice via regulation of cholinergic dysfunction and oxidative stress.

Cholinergic dysfunction and oxidative stress are the most common causes of Alzheimer's disease (AD). Safflower seed contains various anti-oxidant and cholinergic improvement compounds, such as serotonin and its derivatives. In the present study, we investigated the protective effects and mechanisms of a safflower seed extract on scopolamine-induced memory impairment in a mouse model. The safflower seed extract was orally administered at a dose of 100 mg kg-1 day-1, and then behavior tests (such as T-maze and novel object recognition tests) were conducted. Acetyl cholinesterase (AChE) activity, reactive oxygen species (ROS) production, and antioxidant enzymes in the brain were measured. In behavior tests, the novel route exploration and object recognition were improved by the administration of the safflower seed extract, which suggests that the safflower seed extract improves memory function in the scopolamine-treated mouse model. In addition, the safflower seed extract-administered group showed inhibition of the AChE activity and improved cholinergic dysfunction. Furthermore, the administration of the safflower seed extract resulted in lower ROS production and higher antioxidant enzyme levels as compared to the scopolamine-treated group, suggesting the protective role of the safflower seed extract against oxidative stress. The results of the present study suggest that the safflower seed extract improves scopolamine-induced memory deficits via the inhibition of cholinergic dysfunction and oxidative stress. Therefore, safflower seeds might become a promising agent for memory improvement in AD patients.

Cirsium japonicum var. maackii and apigenin block Hif-2α-induced osteoarthritic cartilage destruction.

Although Hif-2α is a master regulator of catabolic factor expression in osteoarthritis development, Hif-2α inhibitors remain undeveloped. The aim of this study was to determine whether Cirsium japonicum var. maackii (CJM) extract and one of its constituents, apigenin, could attenuate the Hif-2α-induced cartilage destruction implicated in osteoarthritis progression. In vitro and in vivo studies demonstrated that CJM reduced the IL-1ß-, IL-6, IL-17- and TNF-α-induced up-regulation of MMP3, MMP13, ADAMTS4, ADAMTS5 and COX-2 and blocked osteoarthritis development in a destabilization of the medial meniscus mouse model. Activation of Hif-2α, which directly up-regulates MMP3, MMP13, ADAMTS4, IL-6 and COX-2 expression, is inhibited by CJM extract. Although cirsimarin, cirsimaritin and apigenin are components of CJM and can reduce inflammation, only apigenin effectively reduced Hif-2α expression and inhibited Hif-2α-induced MMP3, MMP13, ADAMTS4, IL-6 and COX-2 expression in articular chondrocytes. IL-1ß induction of JNK phosphorylation and IκB degradation, representing a critical pathway for Hif-2α expression, was completely blocked by apigenin in a concentration-dependent manner. Collectively, these effects indicate that CJM and one of its most potent constituents, apigenin, can lead to the development of therapeutic agents for blocking osteoarthritis development as novel Hif-2α inhibitors.

Protective role of Cordyceps militaris in Aß1-42-induced Alzheimer's disease in vivo.

According to the "amyloid cascade hypothesis", amyloid-beta (Aß) protein occupied one of the risk factors of Alzheimer's disease (AD). Cordyceps militaris (CM) has been reported to exert anti-inflammatory, anti-oxidant, and neuroprotective activities; however, its activity against cognitive dysfunction has not been studied yet. In this study, the CM ethanol extract was administered with a dose of 100 or 200 mg/kg for 2 weeks, and behavioral assessments were performed for learning and memory function in Aß1-42-induced AD mice models. Supplementation with CM extract enhanced new route consciousness and novel object recognition, and in the Morris water maze test, CM-administered groups showed less time to reach to the hidden platform compared with the control group. Moreover, the CM extract inhibited nitric oxide production and lipid peroxidation in the brain, liver, and kidney. The present study indicated that CM could have the protective role from cognitive impairment and progression of AD.

Protective Effects of Serotonin and its Derivatives, N-Feruloylserotonin and N-(p-Coumaroyl) Serotonin, Against Cisplatin-Induced Renal Damage in Mice.

This study examined whether serotonin and two of its derivatives, N -feruloylserotonin and N -( p -coumaroyl) serotonin, have a renoprotective effect in a mouse model of cisplatin-induced acute renal failure. Cisplatin (20 mg/kg body weight) was administered by intraperitoneal injection to male BALB/c mice that had received oral serotonin, N -feruloylserotonin or N -( p -coumaroyl) serotonin (7.5 mg/kg body weight per day) during the preceding 2 days. At 3 days after the cisplatin injection, serum and renal biochemical factors, oxidative stress, inflammation and apoptosis-related protein expression were evaluated, and histological examinations were performed. Cisplatin caused reduction in body weight and an increase in kidney weight; however, N -( p -coumaroyl) serotonin and N -feruloylserotonin attenuated these effects. Moreover, the serotonin derivatives significantly decreased serum urea nitrogen and creatinine levels. They also significantly reduced the level of reactive oxygen species and upregulated the expression of glutathione peroxidase in the kidney. Furthermore, the serotonin derivatives improved the abnormal expression of mitogen-activated protein kinases activation-dependent inflammation- and apoptosis-related protein and caused less renal damage. These results provide important evidence that N -( p -coumaroyl) serotonin and N -feruloylserotonin exert a pleiotropic effect on several parameters related to oxidative stress, inflammation and apoptosis. The derivatives also have a renoprotective effect in cisplatin-treated mice; however, this effect is higher with N -( p -coumaroyl) serotonin.

Adenosine Induces EBV Lytic Reactivation through ADORA1 in EBV-Associated Gastric Carcinoma.

Cordyceps species are known to contain numerous bioactive compounds, including cordycepin. Extracts of Cordyceps militaris (CME) are used in diverse medicinal purposes because of their bioactive components. Cordycepin, one of the active components of CME, exhibits anti-proliferative, pro-apoptotic, and anti-inflammatory effects. Cordycepin structurally differs from adenosine in that its ribose lacks an oxygen atom at the 3' position. We previously reported that cordycepin suppresses Epstein⁻Barr virus (EBV) gene expression and lytic replication in EBV-associated gastric carcinoma (EBVaGC). However, other studies reported that cordycepin induces EBV gene expression and lytic reactivation. Thus, it was reasonable to clarify the bioactive effects of CME bioactive compounds on the EBV life cycle. We first confirmed that CME preferentially induces EBV gene expression and lytic reactivation; second, we determined that adenosine in CME induces EBV gene expression and lytic reactivation; third, we discovered that the adenosine A1 receptor (ADORA1) is required for adenosine to initiate signaling for upregulating BZLF1, which encodes for a key EBV regulator (Zta) of the EBV lytic cycle; finally, we showed that BZLF1 upregulation by adenosine leads to delayed tumor development in the EBVaGC xenograft mouse model. Taken together, these results suggest that adenosine is an EBV lytic cycle inducer that inhibits EBVaGC development.

Safflower seed extract synergizes the therapeutic effect of cisplatin and reduces cisplatin-induced nephrotoxicity in human colorectal carcinoma RKO cells and RKO-transplanted mice.

Safflower seed is effective against oxidative stress, mediating the activation of the apoptotic signaling pathway in the renal tissues of cisplatin-treated mice. The anticancer activity of safflower in various cancer cell lines has also been reported. The present study was conducted to evaluate the potential synergistic anticancer effects of the co-treatment of safflower seed extracts and cisplatin in RKO cells and in BALB/c mice bearing RKO cell-derived human colorectal tumors. In the cellular system, RKO cells were treated with safflower seed extract in the presence or absence of cisplatin for 48 h and the cytotoxicity was evaluated by using microscopy. In the in vivo system, mice were injected with RKO cells and subsequently orally administered 100 or 200 mg/kg body weight safflower seed extract plus cisplatin-treated or untreated mice for 3 days to examine the inhibitory effect on the tumor. Treatment with safflower seed extract or cisplain to RKO cells resulted in a greater cell death than in with untreated cells. In the RKO cells co-treated with both safflower seed extract and cisplatin, greater cell damage was observed. In addition, mice co-administered safflower seed extract and cisplatin had lower concentrations of serum creatinine, which were indicative of less damage to the kidney, and had a lower solid tumor mass and higher expression of the caspase-3 protein. The results showed that safflower seed extract was highly toxic to RKO cells and inhibited tumor growth in cisplatin-treated mice through renoprotective effects.

Protective effect of Carthamus tinctorius L. seed on oxidative stress and cognitive impairment induced by chronic alcohol consumption in mice.

Chronic alcohol consumption induces damage to the brain that can cause various forms of dementia. An abundance of acetaldehyde is produced by excessive alcohol consumption and accumulates in the body to induce oxidative stress, apoptosis, and inflammation in neuronal cells, which results in learning and cognitive decline. In the present study, C57BL/N mice were orally administered alcohol (16%) and Carthamus tinctorius L. seed (CTS) (100 and 200 mg/kg/day). Behavioral experiments showed that memory and cognitive abilities were significantly higher in the CTS groups than the alcohol-treated control group in the T-maze test, novel object recognition test, and Morris water maze test. In addition, CTS inhibited alcohol-induced lipid peroxidation and nitric oxide production in the brain, kidney, and liver. Moreover, alcohol increased acetylcholinesterase activity in the brain, but this was significantly decreased by the administration of CTS. Therefore, CTS may play role in the prevention of alcohol-related dementia.

Influence of organic acids and heat treatment on ginsenoside conversion.

BACKGROUND: Heat treatments are applied to ginseng products in order to improve physiological activities through the conversion of ginsenosides, which are key bioactive components. During heat treatment, organic acids can affect ginsenoside conversion. Therefore, the influence of organic acids during heat treatment should be considered. METHODS: Raw ginseng, crude saponin, and ginsenoside Rb1 standard with different organic acids were treated at 130°C, and the chemical components, including ginsenosides and organic acids, were analyzed. RESULTS: The organic acid content in raw ginseng was 5.55%. Organic acids were not detected in crude saponin that was not subjected to heat treatment, whereas organic acids were found in crude saponin subjected to heat treatment. Major ginsenosides (Rb1, Re, and Rg1) in ginseng and crude saponin were converted to minor ginsenosides at 130°C; the ginsenoside Rb1 standard was very stable in the absence of organic acids and was converted into minor ginsenosides in the presence of organic acids at high temperatures. CONCLUSION: The major factor affecting ginsenoside conversion was organic acids in ginseng. Therefore, the organic acid content as well as ginsenoside content and processing conditions should be considered important factors affecting the quality of ginseng products.

Comparison of the effect of three licorice varieties on cognitive improvement via an amelioration of neuroinflammation in lipopolysaccharide-induced mice.

BACKGROUND/OBJECTIVES: Neuroinflammation plays critical role in neurodegenerative disorders, such as Alzheimer's disease (AD). We investigated the effect of three licorice varieties, Glycyrhiza uralensis, G. glabra, and Shinwongam (SW) on a mouse model of inflammation-induced memory and cognitive deficit. MATERIALS/METHODS: C57BL/6 mice were injected with lipopolysaccharide (LPS; 2.5 mg/kg, intraperitoneally) and orally administrated G. uralensis, G. glabra, and SW extract (150 mg/kg/day). SW, a new species of licorice in Korea, was combined with G. uralensis and G. glabra. Behavioral tests, including the T-maze, novel object recognition and Morris water maze, were carried out to assess learning and memory. In addition, the expressions of inflammation-related proteins in brain tissue were measured by western blotting. RESULTS: There was a significant decrease in spatial and objective recognition memory in LPS-induced cognitive impairment group, as measured by the T-maze and novel object recognition test; however, the administration of licorice ameliorated these deficits. In addition, licorice-treated groups exhibited improved learning and memory ability in the Morris water maze. Furthermore, LPS-injected mice had up-regulated pro-inflammatory proteins, such as inducible nitric oxide synthase (iNOS), cyclooxygenase-2, interleukin-6, via activation of toll like receptor 4 (TLR4) and nuclear factor-kappa B (NFκB) pathways in the brain. However, these were attenuated by following administration of the three licorice varieties. Interestingly, the SW-administered group showed greater inhibition of iNOS and TLR4 when compared with the other licorice varieties. Furthermore, there was a significant increase in the expression of brain-derived neurotrophic factor (BDNF) in the brain of LPS-induced cognitively impaired mice that were administered licorice, with the greatest effect following SW treatment. CONCLUSIONS: The three licorice varieties ameliorated the inflammation-induced cognitive dysfunction by down-regulating inflammatory proteins and up-regulating BDNF. These results suggest that licorice, in particular SW, could be potential therapeutic agents against cognitive impairment.

Protective Effect of Safflower Seed on Cisplatin-Induced Renal Damage in Mice via Oxidative Stress and Apoptosis-Mediated Pathways.

Cisplatin, a platinum chelate with potent antitumor activity against cancers of the testis, ovary, urinary bladder, prostate, and head and neck, has adverse effects on the kidney, bone marrow, and digestive organs, and its use is particularly limited by nephropathy as a side effect. In the present study, safflower seed extract was administered to a mouse model of cisplatin-induced acute renal failure to investigate its activity. Cisplatin (20[Formula: see text]mg/kg body weight) was administered by intraperitoneal injection to mice that had received oral safflower seed extract (100 or 200[Formula: see text]mg/kg body weight per day) for the preceding 2 days. Three days after the cisplatin injection, serum and renal biochemical factors; oxidative stress, inflammation, and apoptosis-related protein expression; and histological findings were evaluated. Cisplatin-treated control mice showed body-weight, food intake and water intake loss, and increased kidney weight, whereas the administration of safflower seed extract attenuated these effects ([Formula: see text], [Formula: see text]). Moreover, safflower seed extract significantly decreased the renal functional parameters urea nitrogen and creatinine in the serum ([Formula: see text] and [Formula: see text], respectively). Safflower seed extract also significantly reduced the enhanced levels of reactive oxygen species in the kidney observed following cisplatin treatment, with significance. The expression of proteins related to the anti-oxidant defense system in the kidney was down-regulated following cisplatin treatment, but safflower seed extract significantly up-regulated the expression of the anti-oxidant enzyme catalase. Furthermore, safflower seed extract reduced the overexpression of phosphor (p)-p38, nuclear factor-kappa B p65, cyclooxygenase-2, inducible nitric oxide synthase, ATR, p-p53, Bax, and caspase 3 proteins, and mice treated with safflower seed extract exhibited less renal histological damage. These results provide important evidence that safflower seed extract exerts a pleiotropic effect on several oxidative stress- and apoptosis-related parameters and has a renoprotective effect in cisplatin-treated mice.

DNA hypermethylation induced by Epstein-Barr virus in the development of Epstein-Barr virus-associated gastric carcinoma.

Epstein-Barr virus (EBV)-associated gastric carcinoma (EBVaGC) is a recently recognized disease entity defined by the presence of EBV in gastric carcinoma cells. EBV infection causes major epigenetic alterations in the EBV genome and its cellular host genome, suggesting that EBV acts as a direct epigenetic driver for EBVaGC. One of the major epigenetic events in the viral and cellular genomes to control transcription is DNA hypo- or hyper-methylation. Particularly, local and global hypermethylation have been reported in EBVaGC. It is therefore important to understand the molecular mechanisms of DNA hypermethylation during EBVaGC carcinogenesis. To understand the functional roles of DNA methylation and suggest therapeutic target candidates for EBVaGC, we reviewed recent literature reporting DNA hypermethylation in EBVaGC. We summarized the identified candidate genes that are markedly hypermethylated in EBVaGC, which can potentially be targets for chemotherapies with demethylating agents.

The anti-HSV-1 effect of quercetin is dependent on the suppression of TLR-3 in Raw 264.7 cells.

Quercetin is a major component of the plant Glycyrrhiza uralensis, which is largely used as a traditional medicine in Asia. Quercetin has been reported to have several biological activities, which include anti-viral and anti-inflammatory effects. We explored the molecular mechanism linking anti-viral and anti-inflammatory activities using an in vitro herpes simplex virus-1 (HSV-1) infection model. Raw 264.7 cells were infected with HSV-1 in the presence or absence of different concentrations of quercetin and infected cell lysates were harvested 24 h later. HSV plaque reduction assays, western blotting (HSV-1gD, HSV-1 ICP0, TLR-2, 3, 9, NF-κB, IRF3), and real time PCR (HSV-1ICP0, HSV-1UL13, HSV-1UL52) were performed to elucidate the mechanism responsible for the anti-HSV-1 effect of quercetin. In addition, TNF-α level was measured. Quercetin significantly lowered HSV infectivity in Raw 264.7 cells and inhibited the expressions of HSV proteins (gD, ICP0) and genes (ICP0, UL13, UL52). Interestingly, quercetin specifically suppressed the expression of TLR-3, and this led to the inhibitions of inflammatory transcriptional factors (NF-κB and IRF3). These findings suggest that the anti-HSV-1 effects of quercetin are related to the suppression of TLR-3 dependent inflammatory responses in Raw 264.7 cells.

Correction: Genipin Enhances Kaposi's Sarcoma-Associated Herpesvirus Genome Maintenance.

[This corrects the article DOI: 10.1371/journal.pone.0163693.].

Genipin Enhances Kaposi's Sarcoma-Associated Herpesvirus Genome Maintenance.

Kaposi's sarcoma-associated herpesvirus (KSHV) is a Gammaherpesvirus that causes acute infection and establishes life-long latency. KSHV causes several human cancers, including Kaposi's sarcoma, an acquired immune deficiency syndrome (AIDS)-related form of non-Hodgkin lymphoma. Genipin, an aglycone derived from geniposide found in Gardenia jasminoides, is known to be an excellent natural cross-linker, strong apoptosis inducer, and antiviral agent. Although evidence suggests antiviral activity of genipin in several in vitro viral infection systems, no inhibitory effect of genipin on KSHV infection has been reported. Thus, our aim was to determine, using the iSLK-BAC16 KSHV infection system, whether genipin has inhibitory effects on KSHV infection. For this purpose, we evaluated biological effects of genipin on KSHV infection and finally determined the underlying mechanisms responsible for the bioactive effects of genipin. A cytotoxicity assay revealed that genipin caused 50% cytotoxicity at 49.5 µM in iSLK-puro (KSHV-negative) cells and at 72.5 µM in iSLK-BAC16 (KSHV-positive) cells. Caspase 3/7 activities were slightly suppressed by genipin treatment in iSLK-BAC16 cells while significantly induced in iSLK-puro cells. Production of the KSHV latency-associated nuclear antigen (LANA), but not that of the R-transactivator (RTA) protein, was significantly induced by genipin treatment at lower concentration. Consistent with the LANA upregulation, KSHV LANA transcripts, but not RTA transcripts, were expressed at a higher level. Furthermore, KSHV intracellular copy numbers were slightly increased at lower concentration of genipin, while KSHV extracellular copy numbers were significantly increased at higher concentration of genipin. Interestingly, genipin treatment at a lower concentration did induce the expression of DNA (cytosine-5)-methyltransferase 1 (DNMT1); however, a co-immunoprecipitation assay showed that the DNMT1 and LANA induced by genipin did not co-precipitate from iSLK-BAC16 cells. Moreover, a chromatin immunoprecipitation assay demonstrated that genipin treatment enhanced the binding of CCCTC-binding factor (CTCF) to the CTCF-binding site in the KSHV latency control region but suppressed the binding of structural maintenance of chromosomes protein 3 (SMC3) to this site. Genipin treatment also led to the recruitment of additional RNA polymerase to the majority of binding sites of some interesting proteins in the KSHV latency control region, which might be related to the extension of S phase in iSLK-BAC16 cells by genipin treatment. Finally, genipin treatment at lower concentration could promote the KSHV latent replication. In contrast, the treatment at higher concentration could induce the KSHV lytic replication. In conclusion, genipin was shown to be an interesting reagent, which we used to manipulate KSHV life cycle in KSHV latently infected cells.