Effect of Aurea Helianthus stem extract on anti-melanogenesis.

Aurea Helianthus (AH), also known as wild confederate rose or golden sunflower, is a curative herb. It has been used as a medicinal material in China due to its anti-inflammatory, immune regulatory, and anti-oxidant activities. However, its melanogenic effect on skin has not been sufficiently investigated. In this study, we tested whether AH has melanogenic inhibitory activities for the development of effective skin whitening agent. The extract showed inhibition of melanin synthesis and reduced the oxidation of 3, 4-dihydroxyphenilalanine (DOPA) to o-dopaquinone. Additionally, AH downregulated the levels of microphthalmia-associated transcription factor (MITF), tyrosinase and tyrosinase related proteins (TRPs), suggesting that AH has inhibitory effects on melanogenesis. Analysis of the components of AH showed that it contained paprazine and trans-N-feruloyltyramine (FA). We confirmed that the effect of AH resulted from paprazine and FA. Therefore, AH might have potential as an effective candidate for skin whitening.

Weisheng-tang protects against ischemic brain injury by modulating microglia activation through the P2Y12 receptor.

Background: Stroke, a leading cause of death and disability, lacks effective treatments. Post-stroke secondary damage worsens the brain microenvironment, further exacerbating brain injury. Microglia's role in responding to stroke-induced damage in peri-infarct regions is crucial. In this study, we explored Weisheng-tang's potential to enhance ischemic outcomes by targeting microglia. Methods: We induced middle cerebral artery occlusion and reperfusion in mice, followed by behavioral assessments and infarct volume analyses after 48 h, and examined the changes in microglial morphology through skeleton analysis. Results: Weisheng-tang (300 mg/kg) significantly reduced infarction volume and alleviated neurological and motor deficits. The number of activated microglia was markedly increased within the peri-infarct territory, which was significantly reversed by Weisheng-tang. Microglial morphology analysis revealed that microglial processes were retracted owing to ischemic damage but were restored in Weisheng-tang-treated mice. This restoration was accompanied by the expression of the purinergic P2Y12 receptor (P2Y12R), a key regulator of microglial process extension. Weisheng-tang increased neuronal Kv2.1 clusters while suppressing juxtaneuronal microglial activation. The P2Y12R inhibitor-ticagrelor-eliminated the tissue and functional recovery that had been observed with Weisheng-tang after ischemic damage. Discussion: Weisheng-tang improved experimental stroke outcomes by modulating microglial morphology through P2Y12R, shedding light on its neuroprotective potential in ischemic stroke.

Hypoxia-inducible factor α subunit stabilization by NEDD8 conjugation is reactive oxygen species-dependent.

Hypoxia-inducible factor α proteins (HIF-αs) are regulated oxygen dependently and transactivate numerous genes essential for cellular adaptation to hypoxia. NEDD8, a member of the ubiquitin-like family, covalently binds to its substrate proteins, and thus, regulates their stabilities and functions. In the present study, we examined the possibility that the HIF signaling is regulated by the neddylation. HIF-1α expression and activity were inhibited by knocking down APPBP1 E1 enzyme for NEDD8 conjugation but enhanced by ectopically expressing NEDD8. HIF-1α and HIF-2α were identified to be covalently modified by NEDD8. NEDD8 stabilized HIF-1α even in normoxia and further increased its level in hypoxia, which also occurred in von Hippel-Lindau (VHL) protein- or p53-null cell lines. The HIF-1α-stabilizing effect of NEDD8 was diminished by antioxidants and mitochondrial respiratory chain blockers. This suggests that the NEDD8 effect is concerned with reactive oxygen species driven from mitochondria rather than with the prolyl hydroxylase (PHD)/VHL-dependent oxygen-sensing system. Based on these findings, we propose that NEDD8 is an ancillary player to regulate the stability of HIF-1α. Furthermore, given the positive role played by HIF-αs in cancer promotion, the NEDD8 conjugation process could be a potential target for cancer therapy.

Myocardial SSAT induction via AMPK signaling and its implication for ischemic injury.

Spermidine/spermine N-1-acetyl-transferase (SSAT) is a catabolic enzyme that participates in polyamine metabolism. SSAT has been reported to be induced in some organs subjected to ischemia-reperfusion, but its induction mechanism has not been clarified, and little is known about SSAT regulation by ischemia per se. We induced regional ischemia of rat heart by coronary ligation and found that SSAT expression increased in ischemic myocardium. In neonatal rat cardiomyocytes and HEK293 cells, SSAT was up-regulated at the transcriptional step primarily by ATP depletion rather than oxygen deprivation. Moreover, an AMPK inhibitor compound C and AMPKalpha1-silencing RNAs attenuated the SSAT induction by ATP depletion, and an AMPK activator AICAR induced SSAT expression even without ATP depletion. When SSAT was suppressed using siRNA, the caspase activities and Bax/Bcl-2 ratios further increased in ATP depletion. These results suggest that myocardial SSAT is induced by AMPK signaling and function as a cardioprotectant under ATP-depleted conditions.

YC-1 induces S cell cycle arrest and apoptosis by activating checkpoint kinases.

Hypoxia-inducible factor-1alpha (HIF-1alpha) seems central to tumor growth and progression because it up-regulates genes essential for angiogenesis and the hypoxic adaptation of cancer cells, which is why HIF-1alpha inhibition is viewed as a cancer therapy strategy. Paradoxically, HIF-1alpha also leads to cell cycle arrest or the apoptosis of cancer cells. Thus, the possibility cannot be ruled out that HIF-1alpha inhibitors unlock cell cycle arrest under hypoxic conditions and prevent cell death, which would limit the anticancer effect of HIF-1alpha inhibitors. Previously, we reported on the development of YC-1 as an anticancer agent that inhibits HIF-1alpha. In the present study, we evaluated the effects of YC-1 on hypoxia-induced cell cycle arrest and cell death. It was found that YC-1 does not reverse the antiproliferative effect of hypoxia, but rather that it induces S-phase arrest and apoptosis at therapeutic concentrations that inhibit HIF-1alpha and tumor growth; however, YC-1 did not stimulate cyclic guanosine 3',5'-monophosphate production in this concentration range. It was also found that YC-1 activates the checkpoint kinase-mediated intra-S-phase checkpoint, independently of ataxia-telangiectasia mutated kinase or ataxia-telangiectasia mutated and Rad3-related kinase. These results imply that YC-1 does not promote the regrowth of hypoxic tumors because of its cell cycle arrest effect. Furthermore, YC-1 may induce the combined anticancer effects of HIF-1alpha inhibition and cell growth inhibition.

Effects of Anti-Smoking Public Service Announcements on the Attitudes of Korean College Students toward Smoking.

OBJECTIVES: This study aimed to identify the effects of anti-smoking public service announcements on the attitudes of Korean college students toward smoking. METHODS: This study involved students via convenience sampling from seven universities who were randomly assigned to four groups. All groups completed a preliminary questionnaire, before being shown a public service announcement twice, and then completed a post viewing questionnaire. RESULTS: For announcements with positive messages, the proportion of changes in beliefs and attitudes were 39.1% and 19.8%, respectively, whereas those with negative messages showed a greater proportion of changes in the beliefs (59.7%) and attitudes (40.3%). After adjusting for sex and change in belief, the message types and smoking status were identified as factors affecting the change in the participants attitudes. A negative message resulted in a greater change in attitudes (odds ratio [OR], 3.047; 95% confidence interval [CI], 1.847-5.053). Ever-smokers including current smokers showed a greater positive change in attitude than never-smokers (OR, 6.965; 95% CI, 4.107-11.812). CONCLUSION: This study found that positive anti-smoking public service announcements were more effective on attitude change than negative messages. Additionally these announcements were more effective among viewers who were current smokers or had a prior smoking experience.

Performance evaluation of public hospital information systems by the information system success model.

OBJECTIVES: This study was to evaluate the performance of the newly developed information system (IS) implemented on July 1, 2014 at three public hospitals in Korea. METHODS: User satisfaction scores of twelve key performance indicators of six IS success factors based on the DeLone and McLean IS Success Model were utilized to evaluate IS performance before and after the newly developed system was introduced. RESULTS: All scores increased after system introduction except for the completeness of medical records and impact on the clinical environment. The relationships among six IS factors were also analyzed to identify the important factors influencing three IS success factors (Intention to Use, User Satisfaction, and Net Benefits). All relationships were significant except for the relationships among Service Quality, Intention to Use, and Net Benefits. CONCLUSIONS: The results suggest that hospitals should not only focus on systems and information quality; rather, they should also continuously improve service quality to improve user satisfaction and eventually reach full the potential of IS performance.

Vitamin C supplementation prevents testosterone-induced hyperplasia of rat prostate by down-regulating HIF-1alpha.

Benign prostatic hyperplasia (BPH) is a disease that impairs the well-being of many aged men. To alleviate BPH symptoms or to find a cure for this disease, key molecules should be identified that control prostate cell proliferation. Recently, HIF-1alpha has attracted attention in this context, because it is highly expressed in hyperplasic prostates and prevents prostate cell death. Thus, given that vitamin C inhibits HIF-1alpha expression in several malignant tumors, we examined its therapeutic potential in BPH. HIF-1alpha was noticeably induced by testosterone in prostate cells, and this HIF-1alpha induction was abolished by vitamin C. Vascular endothelial growth factor (VEGF) promoter activity reporter assays and semi-quantitative RT-PCR revealed that vitamin C inhibited HIF-1-dependent VEGF expression. Furthermore, HIF-1alpha suppression by vitamin C was rescued by knocking down HIF-prolyl hydroxylase-2, suggesting that vitamin C destabilizes HIF-1alpha via prolyl hydroxylation. Moreover, vitamin C treatment abolished cell proliferation induced by testosterone treatment to the control level. These results suggest that vitamin C inhibits testosterone-induced HIF-1alpha expression and by so doing effectively prevents prostate hyperplasia. In male rats, testosterone treatment for 4 weeks induced prostate hyperplasia. Furthermore, HIF-1alpha and VEGF levels were significantly elevated in hyperplasic prostates. In vitamin C-treated rats, however, most prostate hyperplasia parameters and prostrate HIF-1alpha/VEGF levels were markedly reduced. Accordingly, our findings indicate that vitamin C could be further developed clinically for use as an anti-BPH agent.

HIF-1alpha promotes survival of prostate cells at a high zinc environment.

BACKGROUND: The prostate contains extremely high concentrations of zinc, which may be required for male reproduction. Although zinc is essential for many cellular functions, excessive zinc induces cellular toxicity in general. However, despite exposure to high zinc environment, prostate cells survive and proliferate. Thus, the aim of this study was to identify the intrinsic molecular species that endow prostate cells with the ability to overcome zinc toxicity. METHODS: Immunohistochemistry, histofluorescent zinc staining, Western blot, in vitro binding assay, immunoprecipitation, caspase activity assay, and proteasome activity assay. RESULTS: In rat and human prostates, HIF-1alpha was found to be robustly expressed in epithelial layers containing high zinc levels. Moreover, in cultured prostate cells, HIF-1alpha expression was zinc-dependently induced even under normoxic conditions. Mechanistically, zinc ions inhibited HIF-1-prolyl hydroxylase (PHD) activity, and therefore blocked von Hippel-Lindau tumor suppressor protein (pVHL) binding to HIF-1alpha in vivo and in vitro. The HIF-1alpha stabilization was mediated by oxidative stress induced by zinc ion. Even when prostate cells were treated with high concentrations of zinc ion for extended times, only 10% of cells showed apoptotic death. However, this population of apoptotic cells was increased threefold after HIF-1alpha was knocked-down by siRNA. CONCLUSION: These results suggest that HIF-1alpha functions as an intrinsic defense molecule that enables prostate cells to survive in a zinc-rich environment.

Amphotericin B blunts erythropoietin response to hypoxia by reinforcing FIH-mediated repression of HIF-1.

Amphotericin B (AmB) is widely used for treating severe systemic fungal infections. However, long-term AmB treatment is invariably associated with adverse effects such as anemia. The erythropoietin (EPO) suppression by AmB has been proposed to contribute to the development of anemia. However, the mechanism whereby EPO is suppressed remains obscure. In this study, we investigated the possibility that AmB inhibits the transcription of the EPO gene by inactivating HIF-1, which is a known key transcription factor and regulator of EPO expression. EPO mRNA levels were markedly attenuated by AmB treatment both in rat kidneys and in Hep3B cells. AmB inactivated the transcriptional activity of HIF-1alpha, but did not affect the expression or localization of HIF-1 subunits. Moreover, AmB was found to specifically repress the C-terminal transactivation domain (CAD) of HIF-1alpha, and this repression by AmB required Asn803, a target site of the factor-inhibiting HIF-1 (FIH); moreover, this repressive effect was reversed by FIH inhibitors. Furthermore, AmB stimulated CAD-FIH interaction and inhibited the p300 recruitment by CAD. We propose that this mechanism underlies the unexplained anemia associated with AmB therapy.

Induction of a SSAT isoform in response to hypoxia or iron deficiency and its protective effects on cell death.

Spermidine/spermine N(1)-acetyltransferase (SSAT) is the key enzyme with regard to the maintenance of intracellular polyamine levels. It is an inducible enzyme, which may participate in adaptive responses to environmental stress. However, little is known regarding its responses to oxygen or nutrient deficiencies. Using microarray assays, we discovered that SSAT was enhanced under both oxygen- and iron-deficient conditions. However, RT-PCR revealed that the SSAT mRNA was not induced; rather, an mRNA variant was newly expressed. In this variant, the splicing-in of 110 bases induces early termination, generating a truncated isoform which lacks catalytic motifs. The variant expression occurs in other cancer cells and was irrelevant to both hypoxia-inducible factor 1 and to the redox state. We attempted to determine its role, using stable cell-lines. The expressed isoform was found to promote cell survival under iron-deficient conditions and blocked the cleavage of poly(ADP-ribose) polymerase. This isoform may contribute to the progression of tumors of a more malignant phenotype under poor conditions and may constitute a potential target for anticancer therapy.