Systemic PEGylated TRAIL treatment ameliorates liver cirrhosis in rats by eliminating activated hepatic stellate cells.

UNLABELLED: Liver fibrosis is a common outcome of chronic liver disease that leads to liver cirrhosis and hepatocellular carcinoma. No US Food and Drug Administration-approved targeted antifibrotic therapy exists. Activated hepatic stellate cells (aHSCs) are the major cell types responsible for liver fibrosis; therefore, eradication of aHSCs, while preserving quiescent HSCs and other normal cells, is a logical strategy to stop and/or reverse liver fibrogenesis/fibrosis. However, there are no effective approaches to specifically deplete aHSCs during fibrosis without systemic toxicity. aHSCs are associated with elevated expression of death receptors and become sensitive to tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-induced cell death. Treatment with recombinant TRAIL could be a potential strategy to ameliorate liver fibrosis; however, the therapeutic application of recombinant TRAIL is halted due to its very short half-life. To overcome this problem, we previously generated PEGylated TRAIL (TRAILPEG ) that has a much longer half-life in rodents than native-type TRAIL. In this study, we demonstrate that intravenous TRAILPEG has a markedly extended half-life over native-type TRAIL in nonhuman primates and has no toxicity in primary human hepatocytes. Intravenous injection of TRAILPEG directly induces apoptosis of aHSCs in vivo and ameliorates carbon tetrachloride-induced fibrosis/cirrhosis in rats by simultaneously down-regulating multiple key fibrotic markers that are associated with aHSCs. CONCLUSION: TRAIL-based therapies could serve as new therapeutics for liver fibrosis/cirrhosis and possibly other fibrotic diseases. (Hepatology 2016;64:209-223).

Pulmonary administered palmitic-acid modified exendin-4 peptide prolongs hypoglycemia in type 2 diabetic db/db mice.

Hypoglycemia caused by palmitic-acid modified exendin-4 (Pal-Ex4) administered via the pulmonary route was evaluated and compared with that caused by native Ex4. Pal-Ex4 and Ex4 in solution (each 50 µl) were administered using a microsprayer directly into the trachea of type 2 diabetic db/db mice at 75 or 150 nmol/kg. The lung depositions of Cy5.5-labeled Ex4 or Pal-Ex4 were monitored using an infrared imaging system after administration. The hypoglycemia caused by Pal-Ex4 was found to be 3.4 and 2.3 times greater than that caused by native Ex4 at 75 and 150 nmol/kg, respectively. Furthermore, time to blood glucose level (BGL) rebound to >150 mg/dl for Pal-Ex4 was 3.5 times greater than that of Ex4 (18.1 h vs. 5.2 h at 150 nmol/kg). In particular, the time taken for Pal-Ex4 to reach a BGL nadir was significantly greater than that of Ex4 (~8 h versus 4 h). Furthermore, lung deposition images clearly showed that Pal-Ex4 was slowly absorbed from lungs and barely distributed into kidneys until 8 h post-administration. It is likely that the prolonged hypoglycemia exhibited by Pal-Ex4 was due to; (i) delayed absorption in the lungs and (ii) albumin-binding in the circulation. The study demonstrates that palmitic acid-modified exendin-4 should be viewed as a long-acting inhalation candidate for the treatment of type 2 diabetes.

Evaluation of therapeutic potentials of site-specific PEGylated glucagon-like peptide-1 isomers as a type 2 anti-diabetic treatment: Insulinotropic activity, glucose-stabilizing capability, and proteolytic stability.

PEGylation has been considered to be a good biotechnique for improving the therapeutic value of glucagon-like peptide-1 (GLP-1) analogs for the treatment of type 2 diabetes. Despite the attractive anti-diabetic potentials, GLP-1 does not exert its full biological action because of its extremely short life-time in vivo due to rapid proteolytic degradation. Here, the enzyme-resistant mono-PEGylated GLP-1 isomers substituted at Lys(26)- or Lys(34)-amine were prepared through a newly devised site-specific PEGylation process using a maleic anhydride-protection/deprotection method. The therapeutic potentials of these site-specific PEGylated GLP-1 isomers (Lys(26)- or Lys(34)-PEG-GLP-1) along with His(7)-(N-terminus) PEG-GLP-1 were evaluated by examining their insulinotropic activity, glucose-stabilizing capability, and proteolytic stability. Lys(34)-PEG-GLP-1 was found to have the well-preserved insulinotropic activity (93% efficacy versus GLP-1) in isolated rat pancreatic islets. Furthermore, Lys(34)-PEG-GLP-1 showed the most prominent glucose-stabilizing capability, evaluated via an oral glucose tolerance test in db/db mice by considering the following three crucial factors: (i) maximum blood glucose level (BGL), (ii) required time to lower the BGL below 100mg/dl, and (iii) total hypoglycemic degree. Additionally, Lys(34)-PEG-GLP-1 had longer half-lives than the other PEGylated GLP-1s in the dipeptidyl peptidase IV (DPP IV) inhibitor-treated liver or kidney homogenate, and its stability against DPP IV was also comparable to that of Lys(26)-PEG-GLP-1. Taken together, Lys(34)-PEG-GLP-1 displayed the promising characteristics in all evaluations versus His(7)- or Lys(26)-PEG-GLP-1. This site-specific PEGylated GLP-1 analog would have therapeutic usefulness for treating type 2 diabetes on account of the well-preserved insulinotropic activity, the increased proteolytic stability, and thereby the improved glucose-stabilizing capability.

Rapid screening of blood-brain barrier penetration of drugs using the immobilized artificial membrane phosphatidylcholine column chromatography.

The chromatographic capacity factors (kIAM) of 23 structurally diverse drugs were measured by the immobilized artificial membrane (IAM) phosphatidylcholine chromatography for the prediction of blood-brain barrier (BBB) penetration. The kIAM was determined using the mobile phase consisting of acetonitrile:DPBS (20:80 v/v) and corrected for the molar volume of the solutes (kIAM/MWn). The correlation between kIAM/MWn and CNS penetration was highest when measured at pH 5.5 with the power function of n = 4. This in vitro prediction method was validated with 7 newly synthesized PDE-4 inhibitors. The relationship between in vivo plasma-to-brain concentration ratios and in vitro CNS penetration was excellent (r = 0.959). The developed in vitro prediction method may be used as a rapid screening tool for BBB penetration of drugs with passive transport mechanism, with high success, low cost, and reproducibility.

Labdane diterpenes from Aster spathulifolius and their cytotoxic effects on human cancer cell lines.

Three new labdane diterpenes (1-3), together with eight known diterpenoids, were isolated from a methanol extract of the aerial parts of Aster spathulifolius. The structures of 1-3 were determined as (13R)-labda-7,14-diene 13-O-beta-d-(4'-O-acetyl)fucopyranoside (1), (13R)-labda-7,14-diene 13-O-beta-d-(3'-O-acetyl)fucopyranoside (2), and (13R)-labda-14(15)-en-8,13-diol 13-O-beta-d-fucopyranoside (3), on the basis of spectroscopic and chemical methods. Compounds 1, 2, and four of the known compounds exhibited generally nonspecific cytotoxicity against human A549, SK-OV-3, SK-MEL-2, XF498, and HCT15 tumor cells.

PEGylation of octreotide: II. Effect of N-terminal mono-PEGylation on biological activity and pharmacokinetics.

PURPOSE: : To determine the optimal polyethylene glycol (PEG)-conjugate of octreotide by evaluating the effects of PEGylation chemistry on the biological activity and pharmacokinetic properties. METHODS: : Octreotide was chemically modified by reaction with succinimidyl propionate monomethoxy PEG (SPA-mPEG, molecular weight 2000) or succinimidyl butyraldehyde-mPEG (ALD-mPEG, molecular weight 2000 and 5000). The structural conformation of PEG-octreotides was evaluated by circular dichroism (CD), the biological activity was assessed by measuring the decrease of serum insulin-like growth factor-I levels in rats, and a pharmacokinetic study was performed after subcutaneous administration in rats. The stability against acylation was investigated with poly(D,L -lactide-co-glycolide) (PLGA). RESULTS: : ALD-mPEG was site-specific in PEGylating octreotide at the N-terminus. The mono-PEG-octreotides prepared with ALD-mPEG (mono-ALDPEG-octreotide), which alkyl bond preserves the amine's positive charge, showed complete preservation of biological activity, whereas the PEG-octreotides prepared with SPA-mPEG showed lower activity. In the CD analysis, the spectra of the mono-ALDPEG-octreotides were nearly superimposable with that of native octreotide. The mono-ALDPEG-5K-octreotide showed significantly improved pharmacokinetic properties compared with mono-ALDPEG-2K-octreotide as well as native octreotide. Both mono-ALDPEG-2K- and mono-ALDPEG-5K-octreotides were stable against acylation by degrading PLGA. CONCLUSIONS: : The mono-PEGylation of octreotide at N-terminus with ALD-mPEG produced a conjugate that is biologically and structurally active and stable against acylation by PLGA, and therefore it may serve as a candidate for somatostatin microsphere formulations.

Oral absorption and pharmacokinetics of rebamipide and rebamipide lysinate in rats.

Rebamipide is an anti-ulcer agent exhibiting a low aqueous solubility and a poor oral bioavailability. This study was conducted to examine if the rebamipide lysinate salt form would exhibit improved solubility profiles and higher oral bioavailability compared with rebamipide free acid. Both compounds showed pH-dependent solubility profiles, with the solubility of rebamipide lysinate dramatically improved at a median pH of 5.1 (17-fold increases) over free acid, but the improvement in the solubility was not as pronounced in artificial gastric and intestinal fluids (1.4- and 1.9-fold increases, respectively). The Cl, V(ss) and t1/2 in rats after i.v. injection of rebamipide (0.5 mg/kg) averaged 21.0 +/- 3.2 ml/min/kg, 0.3 +/- 0.0 L/kg, and 0.4 +/- 0.1 hr, respectively. No significant difference was observed in these parameters between rebamipide and rebamipide lysinate. Despite improved solubility profiles, the absolute oral bioavailability of rebamipide lysinate was not increased (5.1 vs. 4.8%) nor did AUC (407.8 vs. 383.6 ng x hr/ml) and C(max) (87.4 vs. 77.0 ng/ml) compared with rebamipide free acid. Rebamipide lysinate, however, showed a more rapid absorption, and initial serum drug concentrations were higher than those found for rebamipide free acid.

A new sesquiterpene lactone from Artemisia rubripes nakai.

The chromatographic separation of a methylene chloride extract of Artemisia rubripes led to the isolation of a new sesquiterpene lactone (3), together with four known compounds, a coumarin (2) and three terpenes (1, 4, and 5). Their structures were characterized to be 1beta,6alpha-dihydroxy-4(15)-eudesmene (1), scopoletin (2), 1alpha,4beta-dihydroxy-8alpha-acetoxy-guaia-2,10(14), 11(13)-triene-6,12-olide (3), 1alpha,4beta-dihydroxy-8alpha-acetoxy-guaia-2,9,11(13)-triene-6,12-olide (4), and beta-sitosterol-3-O-beta-D-glycoside (5) by spectroscopic means.

Monitoring of peptide acylation inside degrading PLGA microspheres by capillary electrophoresis and MALDI-TOF mass spectrometry.

The purpose of this research was to assess the acylation reactions of peptides, salmon calcitonin (sCT), human parathyroid hormone 1-34 (hPTH1-34) and leuprolide, in poly(lactic-co-glycolic acid) (PLGA) microspheres. Capillary electrophoresis (CE) and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) were used for determining and monitoring peptide acylation and quantitating acylation products in the degrading PLGA microspheres. In the degrading PLGA microspheres of sCT and hPTH1-34, the acylation products were observed and determined to be adducts with glycolic acid units from degradable PLGA polymer by MALDI-TOF MS. In the microsphere of leuprolide, however, the acylation product was not observed even after 28 days of incubation at the release medium, which represents the different stabilities among peptides according to the primary structure. As the leuprolide contains tyrosine and serine having hydroxyl group of nucleophilic amino acids, the acylation reaction of peptide is shown to be mainly due to the primary amino groups of N-terminus or lysine residue. The complementary use of CE and MALDI-TOF MS will be useful for searching the counter measures as well as determining the peptide acylation in the manufactured formulations on the market.

Cerebrosides and terpene glycosides from the root of Aster scaber.

Three cerebrosides 2, 3, and 5 and two terpene glycosides 1 and 4 have been isolated from the methanol extract of the root of Aster scaber. Their structures were determined as 3-O-beta-D-glucuronopyranosyl-oleanolic acid methyl ester (1), (2S, 3S, 4R, 2'R, 8Z, 15'Z)-N-2'-hydroxy-15'-tetracosenoyl-1-O-beta-D-glucopyranosyl-4-hydroxy-8-sphingenine (2), (2S, 3S, 4R, 8Z)-N-octadecanoyl-1-O-beta-D-glucopyranosyl-4-hydroxy-8-sphingenine (3), 1alpha-hydroxy-6beta-O-beta-D-glucosyl-eudesm-3-ene (4), and (2S, 3S, 4R, 2'R, 8Z)-N-2'-hydroxy-hexadecanoyl-1-O-beta-D-glucopyranosyl-4-hydroxy-8-sphingenine (5) on the basis of spectroscopic methods.

Phytochemical constituents of Cirsium setidens Nakai and their cytotoxicity against human cancer cell lines.

Five terpenes (1-5), three fatty acids (6-8), two sterols (9 and 11), and a monogalactosyldiacyl glycerol (10) were isolated from the methylene chloride extract of the aerial part of Cirsium setidens. Their chemical structures were determined to be alpha-tocopherol (1), 25-hydroperoxycycloart-23-en-3beta-ol (2), 24-hydroperoxycycloart-25-en-3beta-ol (3), mokko lactone (4), transphytol (5), 9,12,15-octadecatrienoic acid (6), 9,12-octadecadienoic acid (7), hexadecanoic acid (8), acylglycosyl beta-sitosterol (9), (2R)-1,2-O-(9z,12z,15z-dioctadecatrienoyl)-3-O-beta-D-galactopyranosyl glycerol (10) and beta-sitosterol glucoside (11) by spectral evidences. Compound 3 exhibited significant cytotoxic activity against five human cancer cell lines with its ED50 values ranging from 2.66 to 11.25 microM.