Angiopoietin-like protein 1 decreases blood brain barrier damage and edema following focal cerebral ischemia in mice

Angiopoietin-like protein (Angptl) 1, a member of the angiopoietin-related protein family, modulates angiogenesis but little else is known of its physiological role. We found that angptl1 was upregulated at the 7th day after focal cerebral ischemia in normal mice. In order to understand the role of angptl1 in cerebral infarction, we induced focal cerebral ischemia in normal and glial fibrillary acidic protein promoter-angptl1 transgenic mice. In the transgenic mice without ischemia, overexpression of angptl1 in the whole brain led to a decrease in cortical microvascular density. Following focal cerebral ischemia, edema, but not infarct size, was less in transgenic mice relative to wild type littermates. This effect might be due to a reduction in the blood brain barrier breakdown, as confirmed by a decrease in Evans Blue leakage in the early post-ischemic phase. We conclude that angptl1 may have a beneficial role in the preservation of vascular integrity following focal cerebral ischemia.     

Functional analysis of conserved aromatic amino acids in the discoidin domain of Paenibacillus β-1,3-glucanase

The 190-kDa Paenibacillus β-1,3-glucanase (LamA) contains a catalytic module of the glycoside hydrolase family 16 (GH16) and several auxiliary domains. Of these, a discoidin domain (DS domain), present in both eukaryotic and prokaryotic proteins with a wide variety of functions, exists at the carboxyl-terminus. To better understand the bacterial DS domain in terms of its structure and function, this domain alone was expressed in Escherichia coli and characterized. The results indicate that the DS domain binds various polysaccharides and enhances the biological activity of the GH16 module on composite substrates. We also investigated the importance of several conserved aromatic residues in the domain's stability and substrate-binding affinity. Both were affected by mutations of these residues; however, the effect on protein stability was more notable. In particular, the forces contributed by a sandwiched triad (W1688, R1756, and W1729) were critical for the presumable β-sandwich fold.     

Direct solid-phase synthesis of octreotide conjugates: precursors for use as tumor-targeted radiopharmaceuticals.

Somatostatin analogues, such as octreotide, are useful for the visualization and treatment of tumors. Unfortunately, these compounds were produced synthetically using complex and inefficient procedures. Here, we describe a novel approach for the synthesis of octreotide and its analogues using p-carboxybenzaldehyde to anchor Fmoc-threoninol to solid phase resins. The reaction of the two hydroxyl groups of Fmoc-threoninol with p-carboxybenzaldehyde was catalyzed with p-toluenesulphonic acid in chloroform using a Dean-Stark apparatus to form Fmoc-threoninol p-carboxybenzacetal in 91% yield. The Fmoc-threoninol p-carboxybenzacetal acted as an Fmoc-amino acid derivative and the carboxyl group of Fmoc-threoninol p-carboxybenzacetal was coupled to an amine-resin via a DCC coupling reaction. The synthesis of protected octreotide and its conjugates were carried out in their entirety using a conventional Fmoc protocol and an autosynthesizer. The acetal was stable during the stepwise elongation of each Fmoc-amino acid as shown by the averaged coupling yield (> 95%). Octreotide (74 to 78% yield) and five conjugated derivatives were synthesized with high yields using this procedure, including three radiotherapy octreotides (62 to 75% yield) and two cellular markers (72 to 76% yield). This novel approach provides a strategy for the rapid and efficient large-scale synthesis of octreotide and its analogues for radiopharmaceutical and tagged conjugates.     

NPC-14686 (Fmoc-l-homophenylalanine)-induced CaCa2+ increases and death in human prostate cancer cells

The effect of NPC-14686, a potential anti-inflammatory drug, on cytosolic free Ca2+ levels ([Ca2+]i) and growth in PC3 human prostate cancer cells was examined by using fura-2 as a fluorescent Ca2+ indicator and WST-1 as a fluorescent growth dye. NPC-14686 at concentrations above 10 microM increased [Ca2+]i in a concentration-dependent manner with an EC50 value of 100 microM. NPC-14686-induced Ca2+ influx was confirmed by Mn2+ quench of fura-2 fluorescence. The Ca2+ signal was also reduced by removing extracellular Ca2+. Pretreatment with 1 microM thapsigargin (an endoplasmic reticulum Ca2+ pump inhibitor) to deplete the endoplasmic reticulum Ca2+ nearly abolished 200 microM NPC-14686-induced Ca2+ release; and conversely pretreatment with NPC-14686 completely inhibited thapsigargin-induced Ca2+ release. The Ca2+ release induced by 200 microM NPC-14686 was not affected by inhibiting phospholipase C with 2 microM U73122. Overnight treatment with 1-500 microM NPC-14686 decreased cell viability in a concentration-dependent manner. These findings suggest that in human PC3 prostate cancer cells, NPC-14686 increases [Ca2+]i by evoking extracellular Ca2+ influx and releasing intracellular Ca2+ from the endoplasmic reticulum via a phospholiase C-independent manner. NPC-14686 may be cytotoxic to prostate cancer cells.     

15-Deoxy-Delta(12,14)-prostaglandin J(2) suppresses IL-6-induced STAT3 phosphorylation via electrophilic reactivity in endothelial cells

In this study, the effects of 15d-PGJ(2) were investigated in IL-6-activated endothelial cells (ECs). 15d-PGJ(2) was found to abrogate phosphorylation on tyr705 of STAT3 in IL-6-treated ECs, in a dose- and time-dependent manner, but did not inhibit serine phosphorylation of STAT3 and the upperstream JAK2 phosphorylation. Other PPAR activators, such as WY1643 or ciglitazone, had no effect upon IL-6-induced STAT3 phosphorylation. Additionally, neither orthovanadate nor l-NAME treatment reverses the inhibition of STAT3 phosphorylation by 15d-PGJ(2). Otherwise, the effect of 15d-PGJ(2) requires the alpha,beta-unsaturated carbonyl group in the cyclopentane ring. A 15d-PGJ(2) analog, 9,10-Dihydro-15d-PGJ(2), which lack alpha,beta-unsaturated carbonyl group showed no increase in ROS production and no effect in inhibition of IL-6-induced STAT3 phosphorylation. The electrophilic compound, acrolein, mimics the inhibition effect of 15d-PGJ(2). Among the antioxidants, only NAC and glutathione reversed the effects of 15d-PGJ(2). NAC, glutathione and DTT all reversed the inhibition of STAT3 phosphorylation when preincubated with 15d-PGJ(2). The inhibition of ICAM-1 gene expression by 15d-PGJ(2) was abrogated by NAC and glutathione in IL-6-treated ECs. Taken together, these results suggest that 15d-PGJ(2) inhibits IL-6-stimulated phosphorylation on tyr705 of STAT3 dependent on its own electrophilic reactivity in ECs.     

Neuronal responses to myelin are mediated by rho kinase

CNS myelin inhibits axon growth due to the expression of several growth-inhibitory proteins, including myelin-associated glycoprotein, oligodendrocyte myelin glycoprotein and Nogo. Myelin-associated inhibitory proteins activate rho GTPase in responsive neurons. Rho kinase (ROCK) has been implicated as a critical rho effector in this pathway due to the ability of the pharmacological inhibitor Y-27632 to circumvent myelin-dependent inhibition. Y-27632, however, inhibits the activity of additional kinases. Using three independent approaches, we provide direct evidence that ROCKII is activated in response to the myelin-associated inhibitor Nogo. We demonstrate that Nogo treatment enhances ROCKII translocation to the cellular membrane in PC12 cells and enhances ROCKII kinase activity towards an in vitro substrate. In addition, Nogo treatment enhances phosphorylation of myosin light chain II, a known ROCK substrate. Further, we demonstrate that primary dorsal root ganglia neurons can be rendered insensitive to the inhibitory effects of myelin via infection with dominant negative ROCK. Together these data provide direct evidence for a rho-ROCK-myosin light chain-II signaling cascade in response to myelin-associated inhibitors.