Eun-Wook Choi

Foenumoside B from Lysimachia foenum-graecum inhibits adipocyte differentiation and obesity induced by high-fat diet.

We have previously reported anti-obesity effects of Lysimachia foenum-graecum in high-fat diet (HFD)-induced obesity model. Here we isolated a triterpene saponin foenumoside B as an active component of L. foenum-graecum. Foenumoside B blocked the differentiation of 3T3-L1 preadipocytes in a dose-dependent manner with an IC50 of 0.2 μg/ml in adipogenesis assay and suppressed the induction of PPARγ, the master regulator of adipogenesis. Foenumoside B induced the activation of AMP-activated protein kinase (AMPK), and modulated the expression of genes involved in lipid metabolism towards lipid breakdown in differentiated adipocytes. In mouse model, oral administration of foenumoside B (10mg/kg/day for 6 weeks) reduced HFD-induced body weight gain significantly without affecting food intake. Treatment of foenumoside B suppressed lipid accumulation in white adipose tissues and the liver, and lowered blood levels of glucose, triglycerides, ALT, and AST in HFD-induced obese mice. Consistent with the in vitro results, foenumoside B activated AMPK signaling, suppressed the expression of lipogenic genes, and enhanced the expression of lipolytic genes in vivo. Foenumoside B also blocked HFD-induced proinflammatory cytokine production in adipose tissue, suggesting its protective role against insulin resistance. Taken together, these findings demonstrate that foenumoside B represents the anti-obesity effects of L. foenum-graecum, and suggest therapeutic potential of foenumoside B in obesity and obesity-related metabolic diseases.

AdHTS: A high-throughput system for generating recombinant adenoviruses

The need for efficient high-throughput gene delivery system for mammalian cells is rapidly increasing with the growing request for functional genomics studies and drug discoveries in various physiologically relevant systems. However, plasmid-based gene delivery has limitations in transfection efficiency and available cell types. Viral vectors have great advantages over plasmid-based vectors, but construction of recombinant viruses remains to be a big hurdle for high-throughput applications. Here we demonstrate a rapid and simple high-throughput system for constructing recombinant adenoviruses which have been used as efficient gene delivery tools in mammalian systems in vitro and in vivo. By combining Gateway-based site-specific recombination with Terminal protein-coupled adenovirus vector, the adenovirus high-throughput system (AdHTS) generates multiple recombinant adenoviruses in 96-well plates simultaneously without the need for additional cloning or recombination in bacteria or mammalian cells. The AdHTS allows rapid and robust cloning and expression of genes in mammalian cells by removing shuttle vector construction, bacterial transformation, or selection and by minimizing effort in plaque isolation. By shortening the time required to convert whole cDNA library into desired viral vector constructs, the AdHTS would greatly facilitate functional genomics and proteomics studies in various mammalian systems.

Comparison Study on Photodynamic Anticancer Activity of Multifunctional Magnetic Particles by Formation of Cations

In this paper, we have synthesized multifunctional magnetic particles (MNPs) using by two different ferrite submicrometer paticles (Fe₃O₄@HP and CoFe₂O₄@HP) with different surface properties. Two different multifunctional particles have the same particle sizes within the error tolerance of 4.5%. The concentration measurement of the hematoporphyrin (HP) molecule indicates that the weight of HP molecules bonded to the surface of the Fe₃O₄ particles is smaller than that of the CoFe₂O₄ particles. Moreover, we have evaluated their biocompatibilities and photodynamic anticancer activities on mammalian cells. The two MNPs have demonstrated that they both have good biocompatibilities without any cytotoxicity and anticancer activities in the concentration range of 0-50 μg/mL. Specifically, photodynamic-killing activities of both MNPs were measured to be 100% for CoFe₂O₄@HP, and were measured to be 37.9 ± 3.5% and 9.2 ± 2.5% for Fe₃O₄@HP in 25 and 50 μg/mL of both MNPs. These results suggest that both MNPs can be safely used to for clinical photodynamic cancer therapy, although the CoFe₂O₄@HP showed a slightly better photo-killing efficacy compared with the Fe₃O₄@HP in prostate cancer.

Ro 90-7501 inhibits PP5 through a novel, TPR-dependent mechanism

Protein phosphatase 5 (PP5) is a serine/threonine phosphatase that belongs to the PPP family phosphatases. PP5 and the other phosphatases of the PPP family share significantly similar catalytic domain structure. Due to this structural similarity, natural competitive inhibitors such as okadaic acid and cantharidin exhibit broad specificity over the PPP family phosphatases. In this study, we report the identification of three PP5 inhibitors, Ro 90-7501, aurothioglucose, and N-oleoyldopamine, along with a novel inhibitory mechanism of Ro 90-7501. Unlike other inhibitors binding to the phosphatase domain, Ro 90-7501 inhibited PP5 in a TPR-dependent manner. This TPR-dependent PP5 inhibition shown by Ro 90-7501 is a unique and novel inhibitory mechanism, which might be a useful tool for studies of PP5 on both regulatory mechanism and drug discovery.