COX-dependent and -independent pathways in bradykinin-induced anion secretion in rat epididymis

Lysylbradykinin (LBK) added to the apical or basolateral side of cultured rat epididymal monolayers stimulated a rise in short-circuit current (Isc) due to anion secretion. The concentration-response relationships for the apical and basolateral applications have EC50 value of 0.001 microM. The responses to apical or basolateral application of LBK were blocked by WIN64338, a specific B2 receptor antagonist, but not by Des-Arg9,[Leu8]-BK, a specific B1 receptor antagonist, indicating that the LBK effects were mediated through B2 bradykinin receptors. Experiments to desensitize the B2 receptors by repeated stimulation have demonstrated that the responses to apical or basolateral LBK were due to discrete receptors on the apical or basolateral surface. In epithelia clamped in the Ussing chambers, addition of LBK to the apical or basolateral surface evoked release of PGE2 into the apical and basolateral bathing solutions over the first 10 min following hormone addition. LBK added to the basolateral side elicited a greater release than it was added to the apical side. Pretreatment of the epithelia with piroxicam (5 microM) abolished PGE2 release elicited by apical or basolateral LBK and abrogated the Isc induced by basolateral LBK. However, the rise in Isc induced by apical LBK was reduced by 31.3% only. The anion secretion response to apical LBK was not affected by MDL-12330A, an adenylate cyclase inhibitor, but greatly attenuated by thapsigargin, an inhibitor of intracellular Ca2+ release. However, the reverse effects were seen for basolateral LBK. It is concluded that distinct pathways are involved in the stimulation of anion secretion by apical or basolateral LBK. The response to basolateral LBK was COX-dependent, mediated by PGE2 and involves cAMP as second messenger. In contrast, the response to apical LBK is largely COX-independent, not mediated by PCE2 and involves Ca2+ as intracellular messenger.     

Prevention of paraquat-induced apoptosis in human neuronal SH-SY5Y cells by lipocalin-type prostaglandin D synthase

Paraquat is a widely used herbicide that is structurally similar to the known dopaminergic neurotoxicant 1-methyl-4-phenyl-pyridine and acts as a potential etiologic factor for the development of Parkinson's disease. In this study, we investigated the protective roles of lipocalin-type prostaglandin (PG) D synthase (L-PGDS) against paraquat-mediated apoptosis of human neuronal SH-SY5Y cells. The treatment of SH-SY5Y cells with paraquat decreased the intracellular GSH level, and enhanced the cell death with elevation of the caspase activities. L-PGDS was expressed in SH-SY5Y cells, and its expression was enhanced with the peak at 2?h after the initiation of the treatment with paraquat. Inhibition of PGD? synthesis and exogenously added PGs showed no effects regarding the paraquat-mediated apoptosis. SiRNA-mediated suppression of L-PGDS expression in the paraquat-treated cells increased the cell death and caspase activities. Moreover, over-expression of L-PGDS suppressed the cell death and caspase activities in the paraquat-treated cells. The results of a promoter-luciferase assay demonstrated that paraquat-mediated elevation of L-PGDS gene expression occurred through the NF-κB element in the proximal promoter region of the L-PGDS gene in SH-SY5Y cells. These results indicate that L-PGDS protected against the apoptosis in the paraquat-treated SH-SY5Y cells through the up-regulation of L-PGDS expression via the NF-κB element. Thus, L-PGDS might potentially serve as an agent for prevention of human neurodegenerative diseases caused by oxidative stress and apoptosis.     

Butyrate inhibits cytokine-induced VCAM-1 and ICAM-1 expression in cultured endothelial cells: the role of NF-kappaB and PPARalpha

Adhesion and migration of leukocytes into the surrounding tissues is a crucial step in inflammation, immunity, and atherogenesis. Expression of cell adhesion molecules by endothelial cells plays a leading role in this process. Butyrate, a natural short-chain fatty acid produced by bacterial fermentation of dietary fiber, has been attributed with anti-inflammatory activity in inflammatory bowel disease. Butyrate in vitro is active in colonocytes and several other cell types. We have studied the effect of butyrate on expression of endothelial leukocyte adhesion molecules by cytokine-stimulated human umbilical vein endothelial cells (HUVEC). Pretreatment of HUVEC with butyrate-inhibited tumor necrosis factor-alpha (TNFalpha)-induced expression of vascular cell adhesion molecule-1 (VCAM-1) and intracellular cell adhesion molecule-1 (ICAM-1) in a time and concentration-dependent manner. Butyrate at 10 mM/L inhibited interleukin-1 (IL-1)-stimulated VCAM-1 and ICAM-1 expression. The effect of butyrate on cytokine-stimulated VCAM-1 expression was more pronounced than in the case of ICAM-1. Butyrate decreased TNFalpha-induced expression of mRNA for VCAM-1 and ICAM-1. Suppressed expression of VCAM-1 and ICAM-1 was associated with reduced adherence of monocytes and lymphocytes to cytokine-stimulated HUVEC. Butyrate inhibited TNFalpha-induced activation of nuclear factor-kappaB (NF-kappaB) in HUVEC. Finally, butyrate enhanced peroxisome proliferator-activated receptor-alpha (PPARalpha) expression in HUVEC. These results demonstrate that butyrate may have anti-inflammatory properties not only in colonocytes but also in endothelial cells. The anti-inflammatory and (perhaps) antiatherogenic properties of butyrate may partly be attributed to an effect on activation of NF-kappaB and PPARalpha and to the associated expression of VCAM-1 and ICAM-1. The present findings support further investigations on the therapeutic benefits of butyrate in several pathological events involving leukocyte recruitment.     

Highly specific label-free protein detection from lysed cells using internally referenced microcantilever sensors

We report the investigation of label-free protein detection directly from lysed cells using microcantilever sensors. The integration of an internally referenced microcantilever sensor combined with peptide aptamer technology enables scalable and label-free detection of proteins from a complex biological environment (e.g. cell lysate). The internally referenced microcantilever sensor was found to be effective in minimizing both the effects of thermal drift and non-specific binding interactions with the backside of the cantilever, thereby allowing protein detection in a complex biological background. Highly specific peptide aptamers are used to modify the cantilever surface to specifically detect less than 80nM CDK2 protein from yeast cell lysate. This binding of CDK2 on the microcantilever generates a tensile surface stress of average magnitude equal to 70+/-22mN/m. Similar experiments conducted with quartz crystal microbalance (QCM) technology are consistent with the response observed using microcantilever sensors.     

A new species of Jesogammarus from the Iki Island,Japan (Crustacea,Amphipoda, Anisogammaridae)

A new species of anisogammarid amphipod, Jesogammarus (Jesogammarus) ikiensis sp. n., is described from freshwaters in the Iki Island, Nagasaki Prefecture, Japan, based on results of morphological and molecular analyses. The new species is distinguished from all members of the genus by the combination of small number of setae on dorsal margins of pleonites 1–3, short and small number of setae on posterior margins of peduncular articles of antennae, mandibular article 1 without setae, well developed posterior lobes of accessory lobes of coxal gills on gnathopod 2 and pereopods 3–5, and pectinate setae on palmar margin of female gnathopod 2. A key to all the species of Jesogammarus is provided.     

The p90 Ribosomal S6 Kinase (RSK) Is a Mediator of Smooth Muscle Contractility

In the canonical model of smooth muscle (SM) contraction, the contractile force is generated by phosphorylation of the myosin regulatory light chain (RLC₂₀) by the myosin light chain kinase (MLCK). Moreover, phosphorylation of the myosin targeting subunit (MYPT1) of the RLC₂₀ phosphatase (MLCP) by the RhoA-dependent ROCK kinase, inhibits the phosphatase activity and consequently inhibits dephosphorylation of RLC₂₀ with concomitant increase in contractile force, at constant intracellular [Ca²⁺]. This pathway is referred to as Ca²⁺-sensitization. There is, however, emerging evidence suggesting that additional Ser/Thr kinases may contribute to the regulatory pathways in SM. Here, we report data implicating the p90 ribosomal S6 kinase (RSK) in SM contractility. During both Ca²⁺- and agonist (U46619) induced SM contraction, RSK inhibition by the highly selective compound BI-D1870 (which has no effect on MLCK or ROCK) resulted in significant suppression of contractile force. Furthermore, phosphorylation levels of RLC₂₀ and MYPT1 were both significantly decreased. Experiments involving the irreversible MLCP inhibitor microcystin-LR, in the absence of Ca²⁺, revealed that the decrease in phosphorylation levels of RLC₂₀ upon RSK inhibition are not due solely to the increase in the phosphatase activity, but reflect direct or indirect phosphorylation of RLC₂₀ by RSK. Finally, we show that agonist (U46619) stimulation of SM leads to activation of extracellular signal-regulated kinases ERK1/2 and PDK1, consistent with a canonical activation cascade for RSK. Thus, we demonstrate a novel and important physiological function of the p90 ribosomal S6 kinase, which to date has been typically associated with the regulation of gene expression.     

Functions of TET Proteins in Hematopoietic Transformation

DNA methylation is a well-characterized epigenetic modification that plays central roles in mammalian development, genomic imprinting, X-chromosome inactivation and silencing of retrotransposon elements. Aberrant DNA methylation pattern is a characteristic feature of cancers and associated with abnormal expression of oncogenes, tumor suppressor genes or repair genes. Ten-eleven-translocation (TET) proteins are recently characterized dioxygenases that catalyze progressive oxidation of 5-methylcytosine to produce 5-hydroxymethylcytosine and further oxidized derivatives. These oxidized methylcytosines not only potentiate DNA demethylation but also behave as independent epigenetic modifications per se. The expression or activity of TET proteins and DNA hydroxymethylation are highly dysregulated in a wide range of cancers including hematologic and non-hematologic malignancies, and accumulating evidence points TET proteins as a novel tumor suppressor in cancers. Here we review DNA demethylation-dependent and -independent functions of TET proteins. We also describe diverse TET loss-of-function mutations that are recurrently found in myeloid and lymphoid malignancies and their potential roles in hematopoietic transformation. We discuss consequences of the deficiency of individual Tet genes and potential compensation between different Tet members in mice. Possible mechanisms underlying facilitated oncogenic transformation of TET-deficient hematopoietic cells are also described. Lastly, we address non-mutational mechanisms that lead to suppression or inactivation of TET proteins in cancers. Strategies to restore normal 5mC oxidation status in cancers by targeting TET proteins may provide new avenues to expedite the development of promising anti-cancer agents.     

Differential CCR1-mediated chemotaxis signaling induced by human CC chemokine HCC-4/CCL16 in HOS cells

Human CC chemokine-4 (HCC-4)/CCL16 is a chemoattractant for monocytes and lymphocytes. Although HCC-4 binds to multiple CC chemokine receptors, the receptor-mediated signal transduction pathway induced by HCC-4 has not been characterized. Human osteogenic sarcoma cells stably expressing CCR1 were used to investigate HCC-4-mediated chemotaxis signaling events via CCR1. The chemotactic activity of HCC-4 as well as those of other CCR1-dependent chemokines including MIP-1alpha/CCL3, RANTES/CCL5, and Lkn-1/CCL15 was inhibited by the treatment of pertussis toxin, an inhibitor of Gi/Go protein, U73122, an inhibitor of phospholipase C (PLC), and rottlerin, a specific inhibitor of protein kinase Cdelta (PKCdelta). These results indicate that HCC-4-induced chemotaxis signaling is mediated through Gi/Go protein, PLC, and PKCdelta. SB202190, an inhibitor of p38 mitogen activated protein kinase, only blocked the chemotactic activity of HCC-4, but not those of other CCR1-dependent chemokines. SB202190 inhibited HCC-4-induced chemotaxis in a dose-dependent manner (P < 0.01). HCC-4 induces p38 activation in both a time and dose-dependent manner. However, such p38 activation was not induced by other CCR1-dependent chemokines. To further investigate the differential effect of HCC-4, the Ca2+ mobilization was examined. HCC-4 induced no intracellular Ca2+ flux in contrast to other CCR1-dependent chemokines. These results indicate that HCC-4 transduces signals differently from other CCR1-dependent chemokines and may play different roles in the immune response.     

Fine needle aspiration cytology in lupus lymphadenopathy. A case report.

This case report describes the aspiration cytologic characteristics of histologically proven acute lupus lymphadenitis. The aspirate contained numerous lymphoid cells and many amorphous, basophilic, hematoxylin-stained bodies dispersed in a granular, necrotic background that lacked polymorphonuclear leukocytes. The lymphadenopathy was diagnosed cytologically as necrotizing lymphadenitis and histologically as acute lupus lymphadenitis.