Daphne odora Exerts Depigmenting Effects via Inhibiting CREB/MITF and Activating AKT/ERK-Signaling Pathways.

Daphne odora, a blooming shrub, has been traditionally used for various medicinal purposes. However, information on its anti-melanogenic activity and dermal application is limited. In this study, the Daphne odora extract (DOE), with constituents including daphnetin, was used to investigate depigmenting activity and the underlying mechanism of Daphne odora. DOE inhibited in vitro and cellular tyrosinase activity in a dose-dependent manner, and reduced the α-MSH-induced melanin biosynthesis to a control level. The protein expressions of melanin synthesis-related enzymes were also significantly reduced by DOE. Moreover, DOE decreased the phosphorylation of cAMP-response element binding proteins (CREBs) induced by α-MSH in B16F10 cells, while it activated phosphorylated extra-cellular signal-regulated kinases (ERKs) and protein kinase B (AKT) expression. These results suggest that DOE might inhibit the melanogenesis signaling pathways by activating ERK- and AKT-signaling pathways to regulate the expression of CREB and MITF and its downstream pathways. Therefore, DOE could potentially be developed as a depigmenting agent.

Cilastatin Preconditioning Attenuates Renal Ischemia-Reperfusion Injury via Hypoxia Inducible Factor-1α Activation.

Cilastatin is a specific inhibitor of renal dehydrodipeptidase-1. We investigated whether cilastatin preconditioning attenuates renal ischemia-reperfusion (IR) injury via hypoxia inducible factor-1α (HIF-1α) activation. Human proximal tubular cell line (HK-2) was exposed to ischemia, and male C57BL/6 mice were subjected to bilateral kidney ischemia and reperfusion. The effects of cilastatin preconditioning were investigated both in vitro and in vivo. In HK-2 cells, cilastatin upregulated HIF-1α expression in a time- and dose-dependent manner. Cilastatin enhanced HIF-1α translation via the phosphorylation of Akt and mTOR was followed by the upregulation of erythropoietin (EPO) and vascular endothelial growth factor (VEGF). Cilastatin did not affect the expressions of PHD and VHL. However, HIF-1α ubiquitination was significantly decreased after cilastatin treatment. Cilastatin prevented the IR-induced cell death. These cilastatin effects were reversed by co-treatment of HIF-1α inhibitor or HIF-1α small interfering RNA. Similarly, HIF-1α expression and its upstream and downstream signaling were significantly enhanced in cilastatin-treated kidney. In mouse kidney with IR injury, cilastatin treatment decreased HIF-1α ubiquitination independent of PHD and VHL expression. Serum creatinine level and tubular necrosis, and apoptosis were reduced in cilastatin-treated kidney with IR injury, and co-treatment of cilastatin with an HIF-1α inhibitor reversed these effects. Thus, cilastatin preconditioning attenuated renal IR injury via HIF-1α activation.

Cilastatin protects against tacrolimus-induced nephrotoxicity via anti-oxidative and anti-apoptotic properties.

BACKGROUND: Cilastatin (CL) is an inhibitor of dehydropeptidase-I, which is safely used in clinical practice to prevent nephrotoxicity of antibiotics. Tacrolimus (TAC) is the most important immunosuppressant in renal transplantation, but it causes considerable nephrotoxicity. We evaluated the protective effects of CL against chronic TAC-induced nephropathy. METHODS: Chronic nephropathy was induced by administering TAC (1.5 mg/kg/ day, subcutaneous injection) to rats on a low-salt diet for 4 weeks. CL (75 or 150 mg/kg/day, intraperitoneal injection) was concomitantly treated with TAC. Human proximal tubular cells were exposed to TAC (50 µg/mL) with or without CL (250 µg/mL). We investigated the effects of CL on TAC-induced injury in terms of renal function, tubulointerstitial fibrosis, and inflammation. The effects of CL on oxidative stress and apoptosis were evaluated in both in vivo and in vitro models of TAC nephrotoxicity. RESULTS: CL treatment improved TAC-induced renal dysfunction and decreased renal interstitial fibrosis (reduced expression of e-cadherin and TGFß-1) and interstitial inflammation (decreased infiltration of ED-1-positive and osteopontin-positive cells). Compared to TAC treatment alone, CL co-treatment reduced oxidative stress (serum 8-OHdG level and immunoreactivity of 8-OHdG and 4-HHE in renal tissue) and increased renal expression of anti-oxidant enzyme, manganese superoxide dismutase. CL treatment decreased apoptotic cell death (decreased TUNEL-positive cells and reduced expression of active caspase-3) in TAC-treated kidney. In vitro CL treatment prevented tubular cell death from TAC treatment and decreased number of annexin V-positive cells were observed in cilastatin-cotreated cells. CONCLUSION: CL has protective effects against chronic TAC-induced nephrotoxicity owing to its anti-oxidative and anti-apoptotic properties.

Inhibition of collagenase and melanogenesis by ethanol extracts of Orostachys japonicus A. Berger: possible involvement of Erk and Akt signaling pathways in melanoma cells.

Orostachys japonicus is an herb that contains several functional components and has traditionally been used to treat various diseases in Asia. In this study, bioactive components from different parts of the O. japonicus plant were investigated, and the contents of the functional components in ethanol extracts of O. japonicus cultivated in Korea and China were compared. The antioxidant effects of O. japonicus ethanol extracts were investigated using Raw 264.7 cells. It was found that 2,2-diphenyl-1-picrylhydrazyl radical-scavenging activity was significantly decreased in the cells treated with the extracts. Moreover, the novel inhibitory functions of O. japonicus extracts on collagenase, elastase, and tyrosinase were established. We also found that O. japonicus extracts strongly inhibited melanin synthesis in B16F10 melanoma cells by decreasing MITF protein levels and activating the Erk and Akt signaling pathways. Thus, these findings would be useful for developing new cosmetic and pharmaceutical formulations based on O. japonicus extracts.

Cilastatin attenuates vancomycin-induced nephrotoxicity via P-glycoprotein.

BACKGROUND: Oxidative stress is one of the main pathogenic mechanisms in vancomycin-induced nephrotoxicity (VIN). Some studies suggest proximal renal tubular cell necrosis by vancomycin accumulation as a mechanism of nephrotoxicity, and other studies demonstrate that cilastatin has protective effects against drug-induced nephrotoxicity. We investigated whether cilastatin regulates p-gp expression and whether cilastation prevents VIN. MATERIALS AND METHODS: We conducted an in vitro study using an immortalized proximal tubule epithelial cell line from a normal adult human kidney (HK-2) and an in vivo study using male C57BL/6J mice. RESULTS: Vancomycin showed dose-dependent toxicity in the HK-2 cells, and cilastatin attenuated VIN. Vancomycin provoked the reactive oxygen species in a dose-dependent pattern on DCF-DA. Caspase 3/7 activity showed a dose-dependent increase at 6h. We confirmed apoptosis by Terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay at 24h (vancomcyin 2mM). Cilastatin attenuated vancomycin-induced ROS production and apoptosis, and it also attenuated vancomycin-induced P-gp suppression. In vivo, vancomycin (400mg/kg, 600mg/kg IP, 7days) induced acute kidney injury, as demonstrated by elevated blood urea nitrogen and creatinine. Histological examination of the sections indicated greater tubular damage in the vancomycin-treated kidney compared with the control. TUNEL-positive cells decreased significantly in the mouse kidney with cilastatin and vancomycin. Bax/Bcl-2 ratio were significantly increased in the vancomycin-treated kidney. Cilastatin 300mg/kg treatment significantly decreased the vancomycin concentrations in the blood and kidney. CONCLUSION: Our study showed that mechanism of VIN might be involved, at least in part, in suppressing P-gp function, and cilastatin attenuated VIN.

Imbalance of mitochondrial dynamics in Drosophila models of amyotrophic lateral sclerosis.

Amyotrophic lateral sclerosis (ALS) is the most common neurodegenerative disease, characterized by progressive and selective loss of motor neurons in the brain and spinal cord. DNA/RNA-binding proteins such as TDP-43, FUS, and TAF15 have been linked with the sporadic and familial forms of ALS. However, the exact pathogenic mechanism of ALS is still unknown. Recently, we found that ALS-causing genes such as TDP-43, FUS, and TAF15 genetically interact with mitochondrial dynamics regulatory genes. In this study, we show that mitochondrial fission was highly enhanced in muscles and motor neurons of TDP-43, FUS, and TAF15-induced fly models of ALS. Furthermore, the mitochondrial fission defects were rescued by co-expression of mitochondrial dynamics regulatory genes such as Marf, Opa1, and the dominant negative mutant form of Drp1. Moreover, we found that the expression level of Marf was decreased in ALS-induced flies. These results indicate that the imbalance of mitochondrial dynamics caused by instability of Marf is linked to the pathogenesis of TDP-43, FUS, and TAF15-associated ALS.

Discovery of potent, selective, and orally bioavailable PDE5 inhibitor: Methyl-4-(3-chloro-4-methoxybenzylamino)-8-(2-hydroxyethyl)-7-methoxyquinazolin-6-ylmethylcarbamate (CKD 533).

In a continuing effort to discover novel PDE5 inhibitors, we have successfully found quinazolines with 4-benzylamino substitution as potent and selective PDE5 inhibitors. Initial lead compound (1) was found to be easily metabolized when incubated with human liver microsomes mainly through C6 amide hydrolysis. Blocking of this metabolic hot spot led to discovery of 10 (CKD533) which is highly potent, selective and orally efficacious in conscious rabbit model for erectile dysfunction and now is undergoing preclinical toxicology study.

Quinazolines as potent and highly selective PDE5 inhibitors as potential therapeutics for male erectile dysfunction.

In an effort to minimize side effects associated with low selectivity against PDE isozymes, we have successfully identified a series of 6,7,8-substituted quinzaolines as potent inhibitors of PDE5 with high level of isozyme selectivity, especially against PDE6 and PDE11. PDE5 potency and isozyme selectivity of quinazolines were greatly improved with substitutions both at 6- and 8-position. The synthesis, structure-activity relationships and in vivo efficacy of this novel series of potent PDE5 inhibitors are described.

The efficacy and safety of clopidogrel resinate as a novel polymeric salt form of clopidogrel.

A novel polymeric salt of clopidogrel, clopidogrel resinate, was prepared as a anticoagulant drug. To prove the feasibility as a new active substance, clopidogrel resinate was evaluated for its efficacy and safety. In accelerated stability tests, the clopidogrel resinate tablet (Pregrel) showed less brown discoloration and fewer impurities than the clopidogrel bisulfate tablets under open and closed conditions. In toxicity tests, no deaths occurred after a single dose of up to 2000 mg/kg/day and 13-week repeated doses of up to 625 mg/kg/day in rats without abnormal symptoms compared to clopidogrel bisulfate. When clopidogrel resinate was treated onto Caco-2 cell monolayers, clopidogrel, but not the resin, permeated across the cells with a hight permeation coefficient (Papp) of 13.5 +/- 1.13 x 10(-6) cm/sec. Clopidogrel resinate and clopidogrel bisulfate showed similar pharmacokinetics following oral administration to beagle dogs. A single oral administration of clopidogrel resinate dose-dependently inhibited ADP-induced ex vivo aggregation up to 30 mg/kg in rats. In conclusion, clopidogrel resinate was proved to be an efficient and safe polymeric salt as a candidate for a new clopidogrel salt.