Pannexin 1 Channels Play Essential Roles in Urothelial Mechanotransduction and Intercellular Signaling

Urothelial cells respond to bladder distension with ATP release, and ATP signaling within the bladder and from the bladder to the CNS is essential for proper bladder function. In other cell types, pannexin 1 (Panx1) channels provide a pathway for mechanically-induced ATP efflux and for ATP-induced ATP release through interaction with P2X₇ receptors (P2X₇Rs). We report that Panx1 and P2X₇R are functionally expressed in the bladder mucosa and in immortalized human urothelial cells (TRT-HU1), and participate in urothelial ATP release and signaling. ATP release from isolated rat bladders induced by distention was reduced by the Panx1 channel blocker mefloquine (MFQ) and was blunted in mice lacking Panx1 or P2X₇R expression. Hypoosmotic shock induced YoPro dye uptake was inhibited by MFQ and the P2X₇R blocker A438079 in TRT-HU1 cells, and was also blunted in primary urothelial cells derived from mice lacking Panx1 or P2X₇R expression. Rinsing-induced mechanical stimulation of TRT-HU1 cells triggered ATP release, which was reduced by MFQ and potentiated in low divalent cation solution (LDPBS), a condition known to enhance P2X₇R activation. ATP signaling evaluated as intercellular Ca²⁺ wave radius was significantly larger in LDPBS, reduced by MFQ and by apyrase (ATP scavenger). These findings indicate that Panx1 participates in urothelial mechanotransduction and signaling by providing a direct pathway for mechanically-induced ATP release and by functionally interacting with P2X₇Rs.     

A Linkage between SmeIJK Efflux Pump,Cell Envelope Integrity,and σE-Mediated Envelope Stress Response in Stenotrophomonas maltophilia

Resistance nodulation division (RND) efflux pumps, such as the SmeIJK pump of Stenotrophomonas maltophilia, are known to contribute to the multidrug resistance in Gram-negative bacteria. However, some RND pumps are constitutively expressed even though no antimicrobial stresses occur, implying that there should be some physical implications for these RND pumps. In this study, the role of SmeIJK in antimicrobials resistance, envelope integrity, and σ^E-mediated envelope stress response (ESR) of S. maltophilia was assessed. SmeIJK was involved in the intrinsic resistance of S. maltophilia KJ to aminoglycosides and leucomycin. Compared with the wild-type KJ, the smeIJK deletion mutant exhibited growth retardation in the MH medium, an increased sensitivity to membrane-damaging agents (MDAs), as well as activation of an σ^E-mediated ESR. Moreover, the expression of smeIJK was further induced by sub-lethal concentrations of MDAs or surfactants in an σ^E-dependent manner. These data collectively suggested an alternative physiological role of smeIJK in cell envelope integrity maintenance and σ^E-mediated ESR beyond the efflux of antibiotics. Because of the necessity of the physiological role of SmeIJK in protecting S. maltophilia from the envelope stress, smeIJK is constitutively expressed, which, in turn, contributes the intrinsic resistance to aminoglycoside and leucomycin. This is the first demonstration of the linkage among RND-type efflux pump, cell envelope integrity, and σ^E-mediated ESR in S. maltophilia.     

几株杆状病毒包涵体蛋白双向高压电泳指纹图谱比较

用蔗糖密度梯度离心提纯的6种昆虫病毒包涵体(BsNPV1,BsNPV2,BtNPV,EpNPV,PrGV,PxGV)经DAS碱解,粗提纯的包涵体蛋白经Sepharose-6B柱层析和Caaalco-prep-disc法进一步纯化后,在SDS-PAGE中显示为一条分子量约28,000d的带。用常规双向免疫扩散法检查各种包涵体蛋白之间的差异,结果表明血清学BsNPV与BtNPV,PrGV与PxGV之间都是不可分辩的。6种包涵体蛋白的双向高压指纹图谱表明,它们的指纹图谱都不同程度地存在着一些相同或十分相似的肽点。就每种病毒的指纹图谱又都是独特的,NPV间相似性低于GV间相似性。我们认为NPV和GV的包涵体蛋白在结构上存在着一些相同的或相似的保守区域,但不同种之间在整个一级结构上是有差异的。利用包涵体蛋白的指纹图谱鉴定杆状病毒是个灵敏可行的方法。     

The Root Extract of Gentiana macrophylla Pall. Alleviates Cardiac Apoptosis in Lupus Prone Mice

The roots of the perennial herb Gentiana macrophylla Pall. (GM) are known as Qinjiao, which has been used for centuries to treat systemic lupus erythematosus (SLE). However, little is known about the effects of GM on cholesterol-aggravated cardiac abnormalities in SLE, and the mechanisms thereof. This study investigates whether GM exhibits anti-apoptotic effects, focusing on the left ventricle (LV) of NZB/W F1 mice fed with high-cholesterol diet. The morphology and apoptotic status of ventricular tissues were determined by microscopy and Terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay. Levels of apoptotic biomarkers were determined by immunoblotting. The results thus obtained revealed that GM significantly reduced the cholesterol-aggravated apoptosis of LV in NZB/W F1 mice by suppressing both intrinsic and extrinsic apoptotic pathways. Additionally, GM significantly increased the cardiac insulin-like growth factors (IGF)-1 survival signaling and anti-apoptotic proteins in LV tissues. Accordingly, GM is considered to be beneficial in alleviating cholesterol-aggravated cardiac damage in SLE, and therefore constitute an alternative treatment for SLE patients with cardiac abnormalities.     

Involvement of cathepsin E in exogenous antigen processing in primary cultured murine microglia.

We have attempted to elucidate an involvement of cathepsin E (CE) in major histocompatibility complex class II-mediated antigen presentation by microglia. In primary cultured murine microglia, CE was localized mainly in early endosomes and its expression level was markedly increased upon stimulation with interferon-gamma. Pepstatin A, a specific inhibitor of aspartic proteases, significantly inhibited interleukin-2 production from an OVA-(266-281)-specific T helper cell hybridomas upon stimulation with native OVA presented by interferon-gamma-treated microglia. However, pepstatin A failed to inhibit the presentation of OVA-(266-281) peptide. The possible involvement of CE in the processing of native OVA into antigenic peptide was further substantiated by that digested fragments of native OVA by CE could be recognized by OVA-specific Th cells. Cathepsin D also degraded native OVA into antigenic peptide, whereas microglia prepared from cathepsin D-deficient mice retained an ability for antigen presentation. On the other hand, the requirement for cysteine proteases such as cathepsins S and B in the processing of invariant chain (Ii) was confirmed by immunoblot analyses in the presence of their specific inhibitors. In conclusion, CE is required for the generation of an antigenic epitope from OVA but not for the processing of Ii in microglia.     

Tissue-specific expression in transgenic mice directed by the 5'-flanking sequences of the human gene encoding interphotoreceptor retinoid-binding protein

Interphotoreceptor retinoid-binding protein (IRBP) is an extracellular protein that has been suggested to participate in the visual process as a carrier for visual retinoids. A chimeric gene composed of the human IRBP promoter fused to the bacterial reporter gene chloramphenicol acetyltransferase (CAT) was used to generate transgenic mice. Analysis of six transgenic families revealed that the CAT gene, concomitant with the endogenous IRBP gene, was expressed primarily in the retina and, to a lesser extent, in the pineal gland. These results establish that a 1.3-kilobase fragment from the 5' end of the human IRBP gene is sufficient to direct transgene expression to a visual subdivision of the central nervous system.     

Mouse/human chimeric anti-HIV-1 gp120 antibody to the principal neutralizing determinant: Tolerability and pharmacokinetics in cynomolgus monkeys,Macaca fascicularis

In preparing for testing a pharmaceutical grade preparation of chimeric (mouse/human) antibody CGP 47 439 in HIV-1 infected individuals, it was administered toMacaca fascicularis (cynomolgus) monkeys to study tolerability, immunogenicity and pharmacokinetics. Four groups of monkeys, three males and three females per group, received respectively four infusions of 0, 1.43, 4.3, and 14.3 mg of CGP 47 4391 kg body weight at one-week intervals. The chimeric antibody induced no fever, was tolerated well throughout the 50-day observation period, elicited no tissue damage and no anti-antibody response. The pharmacokinetic profile was similar at all dose levels with a mean T_1/2 of 14.2 h (range 11.8–19.3 h) and a mean T_1/2 of 172.6h (range 137.2–220.5h). Following four successive antibody infusions serum concentrations of CGP 47 439 increased without reaching a steady state, and its measured concentrations were comparable to the simulated values. Collectively the study has provided safety and pharmacokinetic data that would allow human studies with this antibody in AIDS patients.     

The implementation of the consensus on the management of Helicobacter pylori and barriers to consensus

Background

A consensus on the management of Helicobacter pylori has been developed. We aimed to assess whether dissemination through continuing medical education (CME) could enhance the adoption of this consensus among clinicians and to explore potential barriers to acceptance.

Materials and methods

Four CME courses were held to disseminate the consensus. Adoption surveys were performed to evaluate participants’ behavior in the past and their commitment to adopt the consensus in future clinical practice after CME. The gaps and barriers to adoption were also surveyed.

Results

A total of 240 physicians had attended the CME courses and received surveys with the 22 statements/substatements of the consensus. Before CME, adoption was good in six, fair in ten, and poor in six. After CME, 21 statements had either an initial >90% adoption or improvement to good or fair (P < 0.001), but one still had poor even though it showed improvement (P = 0.02). Although commitment was good or fair after CME, there was a >20% gap between “commitment” and “no barrier” to adoption for 11 statements, ten of which had a main barrier of financial incentives. Among the statements with fair or poor commitment after CME, less commitment to adoption and more barriers related to financial incentives were pronounced in clinicians serving in regional/district hospitals or clinics compared to those serving in medical centers.

Conclusions

Continuing medical education may improve the adoption of the H. pylori consensus. The financial incentives were shown to be a main barrier to adoption of the consensus and should be improved.