MCPIP1 Enhances TNF-α-Mediated Apoptosis through Downregulation of the NF-κB/cFLIP Axis

Monocyte chemoattractant protein-1-induced protein 1 (MCPIP1) is rapidly produced under proinflammatory stimuli, thereby feeding back to downregulate excessive inflammation. In this study, we used the stable, inducible expressions of wild-type (WT) MCPIP1 and an MCPIP1-D141N mutant in T-REx-293 cells by means of a tetracycline on (Tet-on) system. We found that WT MCPIP1 but not MCPIP1-D141N mutant expression dramatically increased apoptosis, caspase-3, -7, -8, and -9 activation, and c-Jun N-terminal kinase (JNK) phosphorylation in TNF-α-treated cells. The pan-caspase inhibitor, z-VAD-fmk, and the caspase-1 inhibitor, z-YVAD-fmk, but not the JNK inhibitor, SP600125, significantly reversed apoptosis and caspase activation in TNF-α/MCPIP1-treated cells. Surprisingly, MCPIP1 itself was also cleaved, and the cleavage was suppressed by treatment with the pan-caspase inhibitor and caspase-1 inhibitor. Moreover, MCPIP1 was found to contain a caspase-1/-4 consensus recognition sequence located in residues 234~238. As expected, the WT MCPIP1 but not the MCPIP1-D141N mutant suppressed NF-κB activation, as evidenced by inhibition of IκB kinase (IKK) phosphorylation and IκB degradation using Western blotting, IKK activity using in vitro kinase activity, and NF-κB translocation to nuclei using an immunofluorescence assay. Interestingly, MCPIP1 also significantly inhibited importin α3 and importin α4 expressions, which are major nuclear transporter receptors for NF-κB. Inhibition of NF-κB activation further downregulated expression of the caspase-8 inhibitor, cFLIP. In summary, the results suggest that MCPIP1 could enhance the TNF-α-induced apoptotic pathway through decreasing NF-κB activation and cFLIP expression.

Multifunctionalized Cellulose Nanofiber for Water-Repellent and Wash-Sustainable Coatings on Fabrics

A new synthetic route was developed to modify cellulose nanofiber for water-repellent coatings with great sustainability after multiple washing cycles. Multiple functional groups were grafted on 2,2,6,6-tetramethylpiperidine 1-oxyl radical (TEMPO)-oxidized cellulose nanofibers (TOCN) to achieve superhydrophobic performance and strong adhesion on cotton cloth. First, hexadecylamine (HDA) was used to modify TOCN surface into hydrophobic derivatives via amidation. The amidation-modified TOCN (AMT) were then grafted with a polyisocyanate cross-linking agent (PCA). The final multimodified TOCN (MMT) had hydrophobic alkyls and isocyanate groups on the surface. These surface functional groups were confirmed by Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). After spraying the MMT suspension on cotton fabrics, the isocyanate groups would react with hydroxyl groups on cotton fibers, leading to a uniform conformal layer of MMT on fabric surfaces. The MMT coating showed great water repellence and washing sustainability. A large contact angle of 150° and a small sliding angle of ∼10° were observed. The superhydrophobic performance retained even after 10 laundry washing cycles. Several examples were also demonstrated to show the capability and the possibility of applying this coating material for water-repellent applications.

Cytotoxic mechanism of PLK1 inhibitor GSK461364 against osteosarcoma: Mitotic arrest, apoptosis, cellular senescence, and synergistic effect with paclitaxel

Polo-like kinase 1 (PLK1), a serine/threonine kinase and an oncogene, is crucial in regulating cell cycle progression. PLK1 also has been demonstrated as a potential target of osteosarcoma (OS) by using short hairpin RNA libraries in lentiviral vectors for screening of protein kinase. In preclinical studies, GSK461364, a potent and selective ATP-competitive PLK1 inhibitor, showed antiproliferative activity against multiple tumor cell lines. In the present study, we evaluated the expression level of PLK1 in OS and explored the cytotoxic mechanism of GSK461364 against OS. PLK1 was significantly overexpressed in OS compared with normal osteoblasts and other types of sarcoma. GSK461364 inhibited PLK1 and caused mitotic arrest by inducing G2/M arrest in OS cells. Moreover, GSK461364 exerted a cytotoxic effect by inducing apoptosis in OS, and induced cellular senescence in OS cell lines, as indicated by an increased senescence-associated β-galactosidase activity and enhanced DcR2 and interleukin-1α expression. In addition, we demonstrated a synergistic cytotoxic effect of GSK461364 and paclitaxel, possibly resulting from combined mitotic arrest. In conclusion, the present study revealed that PLK1 was overexpressed in OS and that GSK461364 exerted its cytotoxic effect on OS by inducing mitotic arrest and subsequent apoptosis and induced cellular senescence; therefore, senescence-associated markers can be used as treatment biomarkers, and a combination of GSK461364 and paclitaxel can potentially treat OS.

Development of a high-performance liquid chromatographic method for bioanalytical applications with sulpiride

An improved HPLC method using a silica gel column with fluorescence detection (excitation at 300 nm and emission at 365 nm) was developed for the determination of sulpiride concentrations in plasma. Analysis of sulpiride in plasma samples was simplified by a one-step liquid-liquid extraction after alkaline treatment of only 1 ml of plasma. The low limit of quantitation was 20 ng/ml with a coefficient of variation of less than 20%. A linear range was found from 20 to 1500 ng/ml. This HPLC method was validated with the precision for inter-day and intra-day runs being 0.36-8.01% and 0.29-5.25%, respectively, and the accuracy (standard deviation of mean, SD) for inter-day and intra-day runs being -1.58 to 5.02% and -2.14 to 5.21%, respectively. Bioequivalence of the two products was evaluated in 12 normal healthy male volunteers in a single-dose, two-period, two-sequence, two-treatment cross-over study. Sulpiride plasma concentrations were analyzed with this validated HPLC method. Results demonstrated that the two tablet formulations of sulpiride appear to be bioequivalent.

Development of a high-performance liquid chromatographic method for bioequivalence study of flavoxate tablets

An improved HPLC method was developed for the concentration determination of the metabolite of flavoxate, 3-methyl-flavone-8-carboxylic acid (MFCA), in plasma in an attempt to compare two flavoxate tablet formulations. This HPLC method was validated by examining the precision and the accuracy for inter-day and intra-day runs in a linear concentration range of 0.1-24 microg/ml. The coefficients of variation (C.V.) of inter-day and intra-day assays were 0.24-7.18% and 0.06-5.70%, respectively. The standard errors of mean (S.E.M.) were -0.004-8.68% and -2.52-4.86% for inter-day and intra-day assays, respectively. Bioequivalence of the two formulations was determined on 12 normal healthy male volunteers in a single-dose, two-period, two-sequence, two-treatment crossover study. MFCA plasma concentrations were analyzed with this validated HPLC method. The normal pivotal parameters, AUC(0-last), AUC(0-inf) and Cmax, were calculated and compared using the SAS General Linear Model computer program. The two one-sided t distribution test was also performed, as well as the 90% confidence-interval method, for the mean difference of the three pivotal parameters. The results suggest that these two flavoxate tablet formulations are non-bioequivalent when orally administered in a 400-mg dose of two tablets. This result was consistent with the in vitro dissolution of these two formulations.

Fungal mycelia as the source of chitin and polysaccharides and their applications as skin substitutes

A wovenable skin substitute (Sacchachitin) made from the residue of the fruiting body of Ganoderma tsugae was developed in this study. Chemical analysis revealed that the treated residue was a copolymer of beta-1,3-glucan (ca 60%) and N-acetylglucosamine (ca 40%) with a filamental structure of mycelia form, as demonstrated by both optical and scanning electron microscopy. The pulp-like white residue was then woven into thin, porous sheets 7.0 cm in diameter and 0.1-0.2 mm in thickness by filtration and lyophilized for use as a skin substitute. The wound area produced by dissecting rat skin of full thickness was found to almost completely heal on the side covered with Sacchachitin, whereas the control side covered with cotton gauge was around 6.0 cm2 on the 28th day. Furthermore, the wound healing effects of the chitin sheet from crab shell (Beschitin) and Sacchachitin were not found to be significantly different.