TNFalpha-induced cyclooxygenase 2 not only increases the vasopermeability of blood-brain barrier but also enhances the neutrophil survival in Escherichia coli-induced brain inflammation.

In Escherichia coli-induced brain inflammation, cyclooxygenase-2 was induced not only on brain arterioles at 3 h, but also on infiltrating neutrophils at 9 h post-intracerebral injection. Intravenous injection of E. coli or recombinant TNFalpha also induced cyclooxygenase-2 expression on arterioles. Cyclooxygenase-2 and TNFalpha were co-localized on the arterioles as well as the infiltrating neutrophils by serial-section staining, indicating that cyclooxygenase-2 was induced by TNFalpha. NS398 (a cyclooxygenase-2 selective inhibitor) not only inhibited the increase of blood-brain barrier permeability, but also enhanced the apoptosis of the infiltrating neutrophils after E. coli stimulation. This suggests that TNFalpha-stimulated cyclooxygenase-2 induction play an important role on E. coli-induced brain inflammation. Its inhibition would help the resolution of neutrophil-mediated brain inflammation.     

Forskolin inhibits 5-hydroxytryptamine-induced phosphoinositide hydrolysis and Ca+2 Mobilisation in canine cultured aorta smooth muscle cells.

The effect of forskolin on 5-hydroxytryptamine (5-HT)-induced inositol phosphate (IP) and Ca2+ mobilisation was investigated in canine cultured aorta smooth muscle cells (ASMCs). Pretreatment of ASMCs with forskolin attenuated 5-HT-induced IP accumulation and Ca2+ mobilisation in a time- and concentration-dependent manner. The half-maximal effects (pEC50) of forskolin to attenuate IP and Ca2+ responses to 5-HT occurred at concentrations of 6.28 and 6.64, respectively. Pretreatment of ASMCs with cholera toxin caused a similar inhibition on 5-HT-induced responses. Even after treatment with forskolin for 24 h, the 5-HT-induced responses were still inhibited. The inhibitory effect of forskolin resulted from both a depression of the maximal response and a shift to the right of the concentration-effect curves of 5-HT in these responses. The water-soluble forskolin analogue L-858051 [7-deacetyl-7beta-(gamma-N-methylpiperazino)-butyryl forskolin] significantly inhibited the 5-HT-stimulated IP accumulation. In contrast, the addition of 1,9-dideoxy forskolin, an inactive forskolin analogue, had little effect on IP response. Moreover, SQ-22536 [9-(tetrahydro-2-furanyl)-9-H-purin-6-amine], an inhibitor of adenylate cyclase, and both H-89 [N-(2-aminoethyl)-5-iosquinolinesulphonamide] and HA-1004 [N-(2-guanidinoethyl)-5-iosquinolinesulphonamide], inhibitors of cAMP-dependent protein kinase (PKA), attenuated the ability of forskolin to inhibit the 5-HT-stimulated accumulation of IP in ASMCs. These results indicate that activation of cAMP/PKA might inhibit the 5-HT-stimulated IP accumulation and consequently reduce Ca2+ mobilisation, or inhibit both responses independently.     

Different effects of Tetrahymena IFT172 domains on anterograde and retrograde intraflagellar transport

Intraflagellar transport (IFT) particles are multiprotein complexes that move bidirectionally along the cilium/flagellum. The Tetrahymena IFT172 gene encodes a protein with an N-terminal WD domain (WDD) and a C-terminal repeat domain (RPD). Epitope-tagged Ift172p localized to the basal body and in cilia along the axoneme, and IFT172 knockout cells lost cilia and motility. Using serial deletion constructs to rescue the knockout cells, we found that neither the WDD nor the RPD alone is sufficient to assemble cilia. Ift172p containing only the WDD or the RPD failed to enter cilia. Constructs with a partial truncation of the RPD still rescued although cilia were assembled less efficiently, indicating that the WDD and a part of the RPD are sufficient for anterograde transport. Partial truncation of the RPD caused the accumulation of truncated Ift172p itself and of Ift88p at ciliary tips, suggesting that IFT turnaround or retrograde transport was affected. These results implicate different regions of Ift172p in different steps of the IFT process.     

Biological and Molecular Categorization of Strains of Banana bunchy top virus

Banana bunchy top virus (BBTV), a complex circular single‐stranded DNA virus with multiple genomic components, is a destructive pathogen in banana‐cultivating areas worldwide. Based on symptoms (such as vein clearing, green streak on pseudostem, leaf atrophy, bunchy top and stunting) as well as polymerase chain reaction (PCR) amplification patterns with different primer pairs, all BBTV isolates collected from Taiwan and other countries can be divided into five distinctive strains. Three primer pairs, C1, stem‐loop common region (CR‐SL) and TS were used for PCR amplifications. Strain 1, which induces conspicuous symptoms, is a common severe strain; it reacted positively with C1 and CR‐SL but negatively with TS in the PCR assays, so its PCR pattern was indicated as ‘+/+/?’ for C1, CR‐SL and TS primer pairs, respectively. Strain 2 seemed to be a Taiwan‐specific severe strain which induced severe symptoms, and its PCR pattern was ‘+/+/+’ as it showed positive reactions with all three primer pairs. Strain 3, causing the most severe symptoms, is a Malaysia‐specific severe strain whose PCR pattern is ‘?/+/?’. Strain 4 induced moderately severe symptoms and is an intermediate strain whose PCR pattern is ‘?/+/?’. Strain 5 is a mild strain; it did not induce symptoms in banana and it reacted positively with C1, CR‐SL and TS primer pairs. Interestingly, an additional 537‐bp fragment was amplified from Strain 5 with the CR‐SL primer pair. The PCR pattern of Strain 5 is therefore indicated as ‘+/++/+’. This study demonstrates that various BBTV strains exist in nature and they differ biologically and also molecularly.     

Distinct functional defect of three novel Brugada syndrome related cardiac sodium channel mutations

The Brugada syndrome is characterized by ST segment elevation in the right precodial leads V1-V3 on surface ECG accompanied by episodes of ventricular fibrillation causing syncope or even sudden death. The molecular and cellular mechanisms that lead to Brugada syndrome are not yet completely understood. However, SCN5A is the most well known responsible gene that causes Brugada syndrome. Until now, more than a hundred mutations in SCN5A responsible for Brugada syndrome have been described. Functional studies of some of the mutations have been performed and show that a reduction of human cardiac sodium current accounts for the pathogenesis of Brugada syndrome. Here we reported three novel SCN5A mutations identified in patients with Brugada syndrome in Taiwan (p.I848fs, p.R965C, and p.1876insM). Their electrophysiological properties were altered by patch clamp analysis. The p.I848fs mutant generated no sodium current. The p.R965C and p.1876insM mutants produced channels with steady state inactivation shifted to a more negative potential (9.4 mV and 8.5 mV respectively), and slower recovery from inactivation. Besides, the steady state activation of p.1876insM was altered and was shifted to a more positive potential (7.69 mV). In conclusion, the SCN5A channel defect related to Brugada syndrome might be diverse but all resulted in a decrease of sodium current.     

Furo[3′,2′:3,4]naphtho[1,2-d]imidazole derivatives as potential inhibitors of inflammatory factors in sepsis

Synthesis and anti-inflammatory effects of certain furo[3′,2′:3,4]naphtho[1,2-d]imidazole derivatives 12–18 were studied. These compounds were synthesized from naphtho[1,2-b]furan-4,5-dione (10) which in turn was prepared from the known 2-hydoxy-1,4-naphthoquinone (7) in a one pot reaction. Furo[3′,2′:3,4]naphtho[1,2-d]imidazole (12) was inactive (IC₅₀ value of >30 μM) while its 5-phenyl derivative 13, with an IC₅₀ value of 16.3 and 11.4 μM against lysozyme and β-glucuronidase release, respectively, was comparable to the positive trifluoperazine. The same potency was observed for 5-furan derivative 16 with an IC₅₀ value of 19.5 and 11.3 μM against lysozyme and β-glucuronidase release, respectively. An electron-withdrawing NO₂ substituted on 5-phenyl or 5-furanyl group led to the devoid of activity as in the cases of 14 and 17. Among them, compound 15 exhibited significant inhibitory effects, with an IC₅₀ value of 7.4 and 5.0 μM against lysozyme and β-glucuronidase release, respectively.For the LPS-induced NO production, the phenyl derivatives 12–15 were inactive while the nitrofuran counterparts 17 and 18 suppress LPS-induced NO production significantly, with an IC₅₀ value of 1.5 and 1.3 μM, respectively, which are more active than that of the positive 1400 W. Compounds 16–18 were capable of inhibiting LPS-induced iNOS protein expression at a dose-dependent manner in which compound 18, with an IC₅₀ of 0.52 μM in the inhibition of iNOS expression, is approximately fivefold more potent than that of the positive 1400 W. In the CLP rat animal model, compound 18 was found to be more active than the positive hydrocortisone in the inhibition of the iNOS mRNA expression in rat lung tissue. The sepsis-induced PGE2 production in rat serum decreased 150% by the pretreatment of 18 in a dose of 10 mg/kg.