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The aim of this study was to investigate the effects of donor cell passage, size and type on the development of nuclear transfer embryos. Porcine cumulus cells, fetal fibroblasts and oviductal epithelial cells from 1-2, 3-6 and 7-10 passages were used for the nuclear transfer. In the oocytes with the cumulus donor cells, fusion and cleavage rates of oocytes and cell numbers per blastocyst among the three different passage groups did not show any differences, but the rates of blastocyst formation from 1-2 and 3-6 passage groups were higher than those from 7-10 passage group. The rates of fusion, cleavage and blastocyst formation, and the cell numbers per blastocyst were higher in the embryos with the sizes of cumulus donor cells compared to the >20 cumulus donor cell. In the oocytes with the fetal fibroblast donor cells, the rate of blastocyst formation from the 3-6 passage group was higher than from 1-2 and 7-10 passage groups. The embryos with the size of 20 fetal fibroblast donor cell showed higher rate of blastocyst formation compared to those with 20 donor cells. In the oocytes with the oviductal epithelial cells, the rates of blastocyst formation from 1-2 and 3-6 passage groups were higher compared to those from 7-10 passage group. The embryos with the sizes of oviductal epithelial donor cells had a higher rate of blastocyst formation compared to those with >20 donor cell. Fusion and cleavage rates of oocytes, and cell numbers per blastocyst among the three different donor cell types from the 3-6 passage did not show any differences. However, the rate of blastocyst formation of somatic cell nuclear transfer (SCNT) embryos with the fetal fibroblast donor cell was higher than that of blastocyst formation of SCNT embryos with the cumulus and oviductal epithelial donor cells.

Use of porcine tissues has been suggested as a promising solution for severe shortage of transplantable human organs. The immediate hurdle for xenotransplantation is acute immune/inflammatory vascular rejection of the transplant. Because endothelial cells play a key role in the initiation and the amplification of inflammation, alteration of gene expression in human endothelial cells, by various inflammatory stimulators has been studied extensively. However, transcriptional changes induced by human and other inflammatory stimulators in porcine endothelial cells have thus far not been studied. In this study, we treated porcine endothelial cells with human tumor necrosis factor (TNF)-alpha, porcine interferon (IFN)-gamma, H(2)O(2) and lypopolysaccharide (LPS) and profiled transcriptional change at 1 hr, 6 hr and 24 hr, using pig oligonucleotide 13K microarray. We found that mRNA species such as chemokine (C-X-C motif) ligand 6 (CXCL6) and Cathepsin S were significantly induced in porcine endothelial cells, as was previously reported with human endothelial cell. We also found that mRNA species including secreted frizzled-related protein 2 (SFRP2), radical S-adenosyl methionine domain containing 2 (RSAD2), structure specific recognition protein 1 (SSRP1) also were highly overexpressed in porcine endothelial cells. This result shows clues to understand underlying mechanisms of xenotransplantation rejection and the highly responsive porcine genes may serve as novel targets to be regulated for improving the function of grafted porcine donor organs.

The transcriptional activation of NF-кB, a critical player in both physiological and pathological cellular responses to diverse cytokines, is dependent on IKK activation. Although molecular mechanisms underlying IKK activation have been well elucidated, the processes that negatively regulate IKK activity are still largely unknown. Using yeast two-hybrid screening, we have identified GβL as an interacting partner of IKKβ. In this study, we demonstrate that GβL interacts with IKKα and IKKβ in vitro and in vivo. The C-terminal WD domains of GβL are required for the interaction with both the kinase domain and leucine zipper domain of IKKβ. Overexpression of GβL inhibits TNFα-induced activation of NF-кB signaling, while down-regulation of GβL expression by small interfering RNA enhances NF-кB activity. GβL constitutively interacts with IKKβ, and this interaction is enhanced by TNFα treatment. GβL also inhibits TNFα-induced phosphorylation of IKKs. Taken together, these data suggest that GβL is involved in the negative regulation of TNFα-stimulated NF-кB signaling through a direct interaction with IKK.

This study was designed to develop a method of liquid storage of boar sperm at 4°C by using the modified Beltsville F5 (BF5) diluent with bovine serum albumin (BSA) and N-acetyl-D-glucosamine. Boar sperm were stored in lactose-egg yolk and N- acetyl-D-glucosamine (LEN), BF5 and Golden-Pig liquid 4 (GPL4) diluents at 4°C for 5 days and were examined for sperm viability, adenosine triphosphate (ATP) and in vitro fertilization (IVF). The percentage of sperm viability in GPL4 diluent was higher than in LEN and BF5 diluent from 1 to 5 days of storage at 4°C. The percentage of sperm viability steadily declined from 1 to 5 days of storage in the three different diluents. Sperm ATP in GPL4 diluent was higher than in LEN and BF5 diluents from 1 to 5 days of storage. Sperm ATP rapidly declined after 5 days of storage in the three different diluents. Porcine oocytes matured in vitro were inseminated with different sperm concentrations of liquid semen stored for 3 days in GPL4 diluent. The percentage of monospermic oocytes did not show any differences from 2.5 to 20×10 5 sperm/ml. However, the percentage of polyspermic oocytes in the sperm concentration of 2.5×10 5 sperm/ml was lower than in concentrations of 5, 10 and 20×10 5 sperm/ml. The percentage of blastocysts from the cleaved oocytes at 2.5×10 5 /ml sperm concentration was significantly lower than at 5, 10 and 20×10 5 sperm/ml concentrations. In conclusion, GPL4 diluent can be stored at 4°C for 5 days and showed higher sperm viability and sperm ATP concentration compared with LEN and BF5 diluents. Also, we found that GPL4 diluent can be used for IVF of porcine oocytes. (Key Words : Fertilization, Liquid Semen, Oocyte, Porcine)

Lysophosphatidic acid (LPA) is a multifunctional lipid mediator involved in triggering tumor cell invasion and metastasis, as well as malignant cell growth. LPA is also known to modulate the colony scattering of epithelial cancers, which is a prerequisite for cell invasion. However, the underlying details of how this is accomplished are not clear. Here we have investigated the roles of specific LPA receptor subtypes in cell scattering. Gastrointestinal carcinoma cell lines were examined for cell scattering activity in response to LPA, and the expression of LPA receptor subtypes was determined by RT-PCR. The effect of down regulation of each LPA receptor in DLD1 cells was determined using a shRNA-lentivirus system. In addition, the effect of overexpression of LPA receptors on cell scattering was investigated using lentivirus expression constructs. The colonies of AGS and DLD1, but not MKN74, cells were dispersed in response to LPA. RT-PCR analysis revealed that the mRNAs of LPA1, LPA2, and LPA3 were present in AGS and DLD1 cells, but only LPA2 mRNA was detected in MKN74 cells. In DLD1 cells, the scattering activity induced by LPA was partially blocked by pretreatment with PP2 and PD98059, inhibitors of src kinase and MEK, respectively. LPA1 knockdown with shRNA decreased the degree of cell scattering induced by LPA. Knockdown of LPA2 or LPA3 had no effect on LPA-induced scattering. In addition, overexpression of LPA1 in DLD1 cells slightly decreased the response time of LPA-induced cell scattering. On the contrary, MKN74 cells expressing exogenous LPA1 did not respond to LPA by scattering. These results demonstrate that LPA1 mediates LPA-stimulated cell scattering of gastrointestinal carcinomas, but that activation of other intracellular pathways, besides those contributing to ERK phosphorylation, is also necessary for cell scattering in response to LPA.

Background: The anaphylatoxin C5a is a potent inflamma- tory molecule generated during complement activation. Although some reports have implicated C5a in xenograft rejection, to date, the molec- ular compatibility between human C5a and porcine C5a receptor (C5aR) has been little studied. To examine the need for pC5aR-deficient pig in xenotransplantaion, we aimed to look at the degree of direct interaction between human C5a (recipient side) and porcine endothelial cells (PECs) and porcine polymorphonuclear neutrophils (PMNs) (donor side). Methods: Following the treatment of human C5a to isolated porcine PMNs, transmigration of PMNs was measured by Transwell system and superoxide generation by cytochrome c reduction assay. Next, the effects of human C5a on several intracellular signaling pathways were further checked; actin cytoskeletal change was observed under a confocal microscope after staining with Alexa Fluor-546-phalloidin, intracellular calcium mobilization was measured by spectrofluorophotometer. The degree of direct effect of human C5a on porcine PMNs was compared with that in human PMNs. Finally, microarray was performed to monitor the effect of human C5a on gene expression of PEC and the expression of several candidate proteins was checked by flow cytometry. Results: We found that human C5a was able to induce chemotaxis, superoxide generation, actin cytoskeletal change, and intracellular cal- cium mobilization in porcine PMNs. However, higher concentration of human C5a was required to stimulate porcine PMNs in comparison with activating human PMNs. The amino acid sequences of porcine C5aR with those of human C5aR showed a sequence homology of only 67%. To elucidate the effect of human C5a to PECs, microarray analysis following the treatment of PECs with human C5a was performed. These data showed that human C5a did not significantly affect gene tran- scription patterns in PECs. Additionally, treatment of PECs with human C5a also did not induce protein expression of several cell adhesion molecules, including vascular cell adhesion molecule-1, intercellular adhesion molecule-1, P-selectin, and E-selectin, or secretion of inter- leukin-8 from PECs. Conclusions: These results suggest that human C5a may play a minor role on PEC activation possibly due to molecular incompatibility across the species barrier.

Ischemic preconditioning (IPC) before subsequent prolonged ischemia is considered an emerging endogenous means of ischemic brain protection. We tested whether IPC induces endogenous neurogenesis in the subventricular zone (SVZ) and angiogenesis in the peri-ischemic area. Middle cerebral artery occlusion was administered to rats by filament insertion for 10 min (IPC) and/or 2 h (prolonged focal ischemia [PFI]). IPC alone increased 5'-bromo-2'-deoxyuridine (BrdU) (+) cells 2.5-fold in the SVZ compared with controls at 7 days. The numbers of BrdU/doublecortin (Dcx) or BrdU/neuronal nuclei (NeuN) double-labeled cells also increased, but extents of BrdU/glial fibrillary acidic protein (GFAP) double-labeling in the SVZ were not different. The IPC+PFI group showed about a 40% reduction in infarct volume. PFI increased BrdU (+) cells in the SVZ, and this was greatly enhanced by IPC treatment. The number of BrdU/Dcx double-labeled cells was strongly increased in ischemic brains administered IPC. Differentiation into mature neurons was also enhanced at 14 and 28 days. In addition, IPC significantly promoted angiogenesis in the ischemic penumbra as indicated by von Willebrand factor (vWF) staining. Our results indicate that IPC enhances neurogenesis in the SVZ even without subsequent PFI, and also enhances neurogenesis and angiogenesis after subsequent PFI. We conclude that IPC confers neuroprotection, and also promotes endogenous neurogenesis and angiogenesis.

Summary Background There are many reports of patients with a severe hydroa vacciniforme (HV)-like eruption in which cutaneous lesions occur in both sun-exposed and non-exposed areas, unlike in true HV. Several patients have died from a malignant haematological neoplasm. In most cases, a latent Epstein–Barr virus (EBV) infection has been detected in the skin lesions. Objectives To describe the clinical and laboratory features of six additional patients with an EBV-associated HV-like eruption. Methods The clinical, histological and immunohistochemical features were reviewed. T-cell receptor γ gene rearrangements were studied using polymerase chain reaction (PCR) and heteroduplex analysis. In-situ hybridization was performed to detect mRNA for EBV in skin biopsy specimens. PCR was performed to screen for EBV infection in the skin lesions of three patients and blood of two patients. Photoprovocation with repeated ultraviolet (UV) A exposure was performed in three patients. Results The severity of the skin lesions and the clinical course varied among the patients. Skin lesions were induced by repeated UVA exposure in three patients and a latent EBV infection was demonstrated in the photoprovoked lesions. Conclusions Three different clinical courses were found in six patients with an HV-like eruption associated with chronic EBV infection: (i) spontaneous remission; (ii) clearing after photoprotection; and (iii) continuous recurrence irrespective of sun exposure. It is possible that there are two patterns of HV-like eruption associated with chronic EBV infection. One is characterized by recurrent necrotic papulovesicles of the face and the other by nodules and facial swelling. It was demonstrated that the skin lesions could be triggered by repeated UVA exposure in the patients showing recurrent necrotic papulovesicles of the face.

Oxidative stress or signaling is widely implicated in apoptosis, ischemia and mitogenesis. Previously, our group reported that the hydrogen peroxide (H2O2)-dependent activation of phospholipase D2 (PLD2) in PC12 cells is involved in anti-apoptotic effect. However, the precise mechanism of PLD2 activation by H2O2 was not revealed. To find H2O2-dependent PLD2-regulating proteins, we immunoprecipitated PLD2 from PC12 cells and found that glyceraldehyde 3-phosphate dehydrogenase (GAPDH) coimmunoprecipitated with PLD2 upon H2O2 treatment. This interaction was found to be direct by in vitro reconstitution of purified GAPDH and PLD2. In vitro studies also indicated that PLD2-associated GAPDH was modified on its reactive cysteine residues. Koningic acid, an alkylator of GAPDH on catalytic cysteine residue, also increased interaction between the two proteins in vitro and enhanced PLD2 activity in PC12 cells. Blocking H2O2-dependent modification of GAPDH with 3-aminobenzamide resulted in the inhibition of the GAPDH/PLD2 interaction and attenuated H2O2-induced PLD2 activation in PC12 cells. From the results, we suggest that H2O2 modifies GAPDH on its catalytic cysteine residue not only to inactivate the dehydrogenase activity of GAPDH but also to endow GAPDH with the ability to bind PLD2 and the resulting association is involved in the regulation of PLD2 activity by H2O2.

Many studies have shown that protein kinase C (PKC) is an important physiological regulator of phospholipase D (PLD). However, the role of PKC in agonist-induced PLD activation has been mainly investigated with a focus on the PLD1, which is one of the two PLD isoenzymes (PLD1 and PLD2) cloned to date. Since the expression of PLD2 significantly enhanced phorbol 12-myristate 13-acetate (PMA)- or bradykinin-induced PLD activity in rat pheochromocytoma PC12 cells, we investigated the regulatory mechanism of PLD2 in PC12 cells. Two different PKC inhibitors, GF109203X and Ro-31-8220, completely blocked PMA-induced PLD2 activation. In addition, specific inhibition of PKC delta by rottlerin prevented PLD2 activation in PMA-stimulated PC12 cells. Concomitant with PLD2 activation, PLD2 became phosphorylated upon PMA or bradykinin treatment of PC12 cells. Moreover, rottlerin blocked PMA- or bradykinin-induced PLD2 phosphorylation in PC12 cells. Expression of a kinase-deficient mutant of PKC delta using adenovirus-mediated gene transfer inhibited the phosphorylation and activation of PLD2 induced by PMA in PC12 cells, suggesting the phosphorylation-dependent regulation of PLD2 mediated by PKC delta kinase activity in PC12 cells. PKC delta co-immunoprecipitated with PLD2 from PC12 cell extracts, and associated with PLD2 in vitro in a PMA-dependent manner. Phospho-PLD2 immunoprecipitated from PMA-treated PC12 cells and PLD2 phosphorylated in vitro by PKC delta were resolved by two-dimensional phosphopeptide mapping and compared. At least seven phosphopeptides co-migrated, indicating the direct phosphorylation of PLD2 by PKC delta inside the cells. Immunocytochemical studies of PC12 cells revealed that after treatment with PMA, PKC delta was translocated from the cytosol to the plasma membrane where PLD2 is mainly localized. These results suggest that PKC delta-dependent direct phosphorylation plays an important role in the regulation of PLD2 activity in PC12 cells.

Mammalian phospholipase D (PLD) has been implicated in the cellular signal transduction pathways leading to diverse physiological events and known to be regulated by many cellular factors. To identify the proteins that interact with PLD, we performed a protein overlay assay with fractions obtained from the sequential column chromatographic separation of rat brain cytosol using purified PLD2 as a probe. A protein of molecular mass 40 kDa, which was detected by anti-PLD antibody with overlaying of the purified PLD2, is shown to be aldolase C by peptide-mass fingerprinting with matrix-assisted laser desorption/ionization-time-of flight mass spectrometry (MALDI-TOF-MS). Aldolase A also showed similar binding properties as aldolase C and was co-immunoprecipitated with PLD2 in COS-7 cells overexpressing PLD2 and aldolase A. The PH domain corresponding to amino acids 201-310 of PLD2 was necessary for the interaction observed in vitro, and aldolase A was found to interact with the PH domain of PLD2 specifically, but not with other PH domains. PLD2 activity was inhibited by the presence of purified aldolase A in a dose-dependent manner, and the inhibition by 50% was observed by the addition of less than micromolar aldolase A. Moreover, the inclusion of the aldolase metabolites fructose 1,6-bisphosphate (F-1,6-P) or glyceraldehyde 3-phosphate (G-3-P) resulted in an enhanced interaction between PLD2 and aldolase A with a concomitant increase in the potential ability of aldolase A to inhibit PLD2, which suggests the existence of a possible regulation of the interaction by the change of intracellular concentrations of glycolytic metabolites.

Tumor angiogenesis is a key event that governs tumor progression and metastasis. It is controlled by the complicated and coordinated actions of pro-angiogenic factors and their receptors that become upregulated during tumorigenesis. Over the past several decades, vascular endothelial growth factor (VEGF) signaling has been identified as a central axis in tumor angiogenesis. The remarkable advent of recombinant antibody technology has led to the development of bevacizumab, a humanized antibody that targets VEGF and is a leading clinical therapy to suppress tumor angiogenesis. However, despite the clinical efficacy of bevacizumab, its significant side effects and drug resistance have raised concerns necessitating the identification of novel drug targets and development of novel therapeutics to combat tumor angiogenesis. This review will highlight the role and relevance of VEGF and other potential therapeutic targets and their receptors in angiogenesis. Simultaneously, we will also cover the current status of monoclonal antibodies being developed to target these candidates for cancer therapy.

Tumor necrosis factor alpha (TNFα)-induced angiogenesis plays important roles in the progression of various diseases, including cancer, wet age-related macular degeneration, and rheumatoid arthritis. However, the relevance and role of vascular cell adhesion molecule-1 (VCAM-1) in angiogenesis have not yet been clearly elucidated. In this study, VCAM-1 knockdown shows VCAM-1 involvement in TNFα-induced angiogenesis. Through competitive blocking experiments with VCAM-1 Ig-like domain 6 (VCAM-1-D6) protein, we identified VCAM-1-D6 as a key domain regulating TNFα-induced vascular tube formation. We demonstrated that a monoclonal antibody specific to VCAM-1-D6 suppressed TNFα-induced endothelial cell migration and tube formation and TNFα-induced vessel sprouting in rat aortas. We also found that the antibody insignificantly affected endothelial cell viability, morphology and activation. Finally, the antibody specifically blocked VCAM-1-mediated cell-cell contacts by directly inhibiting VCAM-1-D6-mediated interaction between VCAM-1 molecules. These findings suggest that VCAM-1-D6 may be a potential novel therapeutic target in TNFα-induced angiogenesis and that antibody-based modulation of VCAM-1-D6 may be an effective strategy to suppress TNFα-induced angiogenesis.

Mammalian phospholipase D (PLD) plays a key role in several signal transduction pathways and is involved in many diverse functions. To elucidate the complex molecular regulation of PLD, we investigated PLD-binding proteins obtained from rat brain extract. Here we report that a 43-kDa protein in the rat brain, beta-actin, acts as a major PLD2 direct-binding protein as revealed by peptide mass fingerprinting in combination with matrix-assisted laser desorption ionization/time-of-flight mass spectrometry. We also determined that the region between amino acids 613 and 723 of PLD2 is required for the direct binding of beta-actin, using bacterially expressed glutathione S-transferase fusion proteins of PLD2 fragments. Intriguingly, purified beta-actin potently inhibited both phosphatidylinositol-4,5-bisphosphate- and oleate-dependent PLD2 activities in a concentration-dependent manner (IC50 = 5 nm). In a previous paper, we reported that alpha-actinin inhibited PLD2 activity in an interaction-dependent and an ADP-ribosylation factor 1 (ARF1)-reversible manner (Park, J. B., Kim, J. H., Kim, Y., Ha, S. H., Kim, J. H., Yoo, J.-S., Du, G., Frohman, M. A., Suh, P.-G., and Ryu, S. H. (2000) J. Biol. Chem. 275, 21295-21301). In vitro binding analyses showed that beta-actin could displace alpha-actinin binding to PLD2, demonstrating independent interaction between cytoskeletal proteins and PLD2. Furthermore, ARF1 could steer the PLD2 activity in a positive direction regardless of the inhibitory effect of beta-actin on PLD2. We also observed that beta-actin regulates PLD1 and PLD2 with similar binding and inhibitory potencies. Immunocytochemical and co-immunoprecipitation studies demonstrated the in vivo interaction between the two PLD isozymes and actin in cells. Taken together, these results suggest that the regulation of PLD by cytoskeletal proteins, beta-actin and alpha-actinin, and ARF1 may play an important role in cytoskeleton-related PLD functions.

Multidrug resistance (MDR), mediated by P-glycoprotein (P-gp), is an in vitro phenomenon observed within tumour cells, suggesting cross-resistance to unrelated drugs, and expression of P-gp may therefore affect the prognosis and incidence of recurrence after treatment. The mutant p53 protein causes reduced tumour suppression. Co-expression of p53 and P-gp is related to short survival, increased tumour activity and drug resistance. The purpose of this study was to measure the expression of p53 protein and P-gp in osteosarcoma tissue and assess its prognostic significance. Fifty-two tumour specimens were evaluated. The correlation between p53 and P-gp expression was significant (P=0.0008). In univariate analysis of survival, p53 protein was not significant (P=0.2) but P-gp was significant (P=0.0001). The co-expression of p53 and P-gp was the strongest indicator of a short survival according to multivariate analysis (P=0.0004).

Caveolae are small plasma membrane invaginations that have been implicated in cell signaling, and caveolin is a principal structural component of the caveolar membrane. Previously we have demonstrated that protein kinase Cα (PKCα) directly interacts with phospholipase D1 (PLD1), activating the enzymatic activity of PLD1 in the presence of phorbol 12-myristate 13-acetate (PMA) [Lee, T. G., et al. (1997) Biochim. Biophys. Acta 1347, 199−204]. In this study, using a detergent-free procedure for the purification of a caveolin-enriched membrane fraction (CEM) and immunoblot analysis, we show that PLD1 is enriched in the CEMs of 3Y1 rat fibroblasts. Purified PLD1 directly bound to a glutathione S-transferase−caveolin-1 fusion protein in in vitro binding assays. The association of PLD1 with caveolin-1 could be completely eliminated by preincubation of PLD1 with an oligopeptide corresponding to the scaffolding domain (amino acids 82−101) of caveolin-1, indicating that caveolin-1 interacts with PLD1 through the sc...

When an inflammatory stimulus is given, vascular endothelial cells express various cell adhesion molecules including the vascular cell adhesion molecule (VCAM)-1. In this study, the possibility of specifically delivering anti-inflammatory drugs to activated endothelial cells by utilizing VCAM-1 as a target receptor was explored by loading celecoxib, a selective cyclooxygenase-2 inhibitor, into liposomes coupled to the Fab' fragment against VCAM-1. Anti-VCAM-1-Fab'-conjugated liposomes were prepared by forming an amide linkage between amino groups of Fab' and the carboxylic group of glutaryl-N-phosphatidylethanolamine in liposomes using 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide as a cross-linker in the presence of sulpho-N-hydroxysuccinimide. The coupling of Fab' to phospholipids constituting liposomes was confirmed by SDS-PAGE analysis. Under our optimized conjugation conditions, 130.0 µg Fab' was coupled to 1 µmol liposomes. Immunoblotting analysis showed that VCAM-1 protein expression could be induced by incubating human umbilical vein endothelial cells (HUVEC) with TNF-α. Confocal laser microsopy analysis revealed that Fab' conjugation to liposomes selectively increased liposomal uptake in TNF-α-pre-stimulated (VCAM-1-expressed) HUVECs, but not in cells without VCAM-1 expression. The concentration of celecoxib loaded in Fab'-conjugated liposomes was 281.1 ± 29 µg/mL, suggesting that liposomal loading also helped to overcome the limitations in celecoxib administration caused by its poor water solubility. Celecoxib loaded in Fab'-conjugated liposomes inhibited prostaglandin E₂ (PGE₂) production induced by TNF-α-pre-stimulation more efficiently than when loaded in conventional liposomes. Therefore, Fab'-conjugated liposomes served as a drug delivery system with dual functions: targeted delivery and solubilizing capacity.

Activation of the vascular endothelium and increased adhesion of circulating leukocytes to the activated endothelium are important events in inflammation and coagulation. Aurintricarboxylic acid (ATA), a triphenylmethyl dye compound, is known to inhibit platelet adhesion by interfering with the binding of von Willebrand factor to platelet glycoprotein Ib. However, the effect of ATA on the inflammatory response of endothelial cells has not yet been investigated. Here, we investigated the functional role and molecular mechanism of ATA on the activation of human endothelial cells. ATA inhibited the expression of intercellular adhesion molecule-1 (ICAM-1), and endothelial cell selectin (E-selectin) was upregulated on human umbilical vein endothelial cells (HUVECs) in response to tumor necrosis factor-α or lipopolysaccharide (LPS). We also observed the inhibitory effect of ATA on LPS-induced mRNA expression of ICAM-1 and E-selectin. Furthermore, ATA inhibited the binding of leukocytes to activated HUVECs. ATA significantly inhibited the nuclear translocation of nuclear factor-κB (NF-κB) and degradation of IκB on activated HUVECs, suggesting that ATA inhibits NF-κB signaling. Finally, three NF-κB inhibitors effectively inhibited the expressions of ICAM-1 and E-selectin on activated endothelial cells. The present data suggest that ATA exerts beneficial effect in various inflammation conditions through inhibition of adhesion molecule expression in activated endothelial cells and the resulting inhibition of leukocytes tissue accumulation.

The transcriptional activation of NF-kappaB, a critical player in both physiological and pathological cellular responses to diverse cytokines, is dependent on IKK activation. Although molecular mechanisms underlying IKK activation have been well elucidated, the processes that negatively regulate IKK activity are still largely unknown. Using yeast two-hybrid screening, we have identified GbetaL as an interacting partner of IKKbeta. In this study, we demonstrate that GbetaL interacts with IKKalpha and IKKbeta in vitro and in vivo. The C-terminal WD domains of GbetaL are required for the interaction with both the kinase domain and leucine zipper domain of IKKbeta. Overexpression of GbetaL inhibits TNFalpha-induced activation of NF-kappaB signaling, while down-regulation of GbetaL expression by small interfering RNA enhances NF-kappaB activity. GbetaL constitutively interacts with IKKbeta, and this interaction is enhanced by TNFalpha treatment. GbetaL also inhibits TNFalpha-induced phosphorylation of IKKs. Taken together, these data suggest that GbetaL is involved in the negative regulation of TNFalpha-stimulated NF-kappaB signaling through a direct interaction with IKK.

Although a severe shortage of organs in transplantation can be overcome by using xenotransplantation of porcine donor organs, profound immune rejection to xenogeneic antigens remains a main obstacle. To elucidate the role of hydrogen peroxide (H(2)O(2)) on xenogeneic immune responses, we investigated its effects on porcine aortic endothelial cells (PAECs). We found that H(2)O(2) can specifically induce vascular cell adhesion molecule-1 (VCAM-1) expression on PAECs, but little on human umbilical vein endothelial cells (HUVECs) and aortic endothelial cells (HAECs). Furthermore, we further confirmed that H(2)O(2) induces activation of NFkappaB in PAECs, but not in HAECs. Interestingly, cell adhesion assay showed that U937, human promonocytic leukocyte, can adhere to PAECs in an H(2)O(2)-dependent manner and by using a neutralizing assay with anti-VCAM-1-specific antibodies, we also found that the interaction is mediated primarily by VCAM-1. Finally, we also demonstrated that up-regulation of VCAM-1 expression on PAECs by reactive oxygen species-producing HL-60, human leukemic neutrophil cells, could be significantly diminished by over-expressing an H(2)O(2)-removing catalase. In summary, our results suggest that NFkappaB-dependent porcine VCAM-1 expression by H(2)O(2) may promote interaction of human leukocyte to PAECs, and thus may play an important role on inducing xenogeneic immune responses.

Regulator of G-protein signaling (RGS) proteins interact with alpha subunits of heterotrimeric G-proteins via the RGS domain and attenuate their activity by accelerating GTPase activity. RGS2, a member of the RGS family, regulates synaptic development via hereto unknown mechanism. In this study, we found that RGS2 directly interacted with tubulin via a short region at the N-terminus: amino acids 41-60. RGS2 enhanced microtubule polymerization in vitro, and the tubulin binding region was necessary and sufficient for this activity. In Vero cells, polymerization of microtubule was stimulated when peptides containing the tubulin binding region were microinjected. Immunocytochemical analysis showed that endogenous RGS2 was localized at the termini of neurites in differentiated PC12 cells. Over-expression of RGS2 enhanced the nerve growth factor-induced neurite outgrowth in PC12 cells, while specific knock-down of endogenous RGS2 suppressed the neurite outgrowth. These findings demonstrate that RGS2 contributes to the neuronal cell differentiation via regulation of microtubule dynamics.

The high incidence of biliary tract carcinoma in patients with anomalous pancreaticobiliary ductal junction (APBDJ) implicates that a compositional alteration in bile may contribute to the genesis of this cancer. Lysophosphatidylcholine (LPC) is generated in the bile of these patients. Given the role of cyclooxygenase-2 (COX-2) in biliary tract carcinogenesis, we postulated that LPC induces COX-2 in cholangiocytes. The effect of LPC on COX-2 expression in cholangiocytes was evaluated by immunoblot analysis, real-time PCR and reporter gene assay. Apoptosis was induced by TRAIL treatment, and quantified using DAPI staining. Lysophosphatidylcholine increased COX-2 protein expression in cholangiocytes in a concentration- and time-dependent manner. LPC-induced Raf-1 activation was responsible for this COX-2 induction. Accordingly, LPC increased COX-2 mRNA levels in a Raf-1 dependent manner by stabilizing COX-2 mRNA. Finally, LPC attenuated TRAIL-mediated apoptosis through a COX-2/PgE2 dependent mechanism. Collectively, these results implicate that LPC inhibits cholangiocyte apoptosis by inducing COX-2 expression via a Raf-1 dependent mechanism. This anti-apoptotic signaling may participate in biliary tract carcinogenesis in APBDJ patients, and therefore, its interruption may be a viable chemopreventative strategy.

Oxidative stress or signaling is widely implicated in apoptosis, ischemia and mitogenesis. Previously, our group reported that the hydrogen peroxide (H2O2)-dependent activation of phospholipase D2 (PLD2) in PC12 cells is involved in anti-apoptotic effect. However, the precise mechanism of PLD2 activation by H2O2 was not revealed. To find H2O2-dependent PLD2-regulating proteins, we immunoprecipitated PLD2 from PC12 cells and found that glyceraldehyde 3-phosphate dehydrogenase (GAPDH) coimmunoprecipitated with PLD2 upon H2O2 treatment. This interaction was found to be direct by in vitro reconstitution of purified GAPDH and PLD2. In vitro studies also indicated that PLD2-associated GAPDH was modified on its reactive cysteine residues. Koningic acid, an alkylator of GAPDH on catalytic cysteine residue, also increased interaction between the two proteins in vitro and enhanced PLD2 activity in PC12 cells. Blocking H2O2-dependent modification of GAPDH with 3-aminobenzamide resulted in the inhibition of the GAPDH/PLD2 interaction and attenuated H2O2-induced PLD2 activation in PC12 cells. From the results, we suggest that H2O2 modifies GAPDH on its catalytic cysteine residue not only to inactivate the dehydrogenase activity of GAPDH but also to endow GAPDH with the ability to bind PLD2 and the resulting association is involved in the regulation of PLD2 activity by H2O2.

The epidermal growth factor (EGF) receptor has an important role in cellular proliferation, and the enzymatic activity of phospholipase C (PLC)-gamma1 is regarded to be critical for EGF-induced mitogenesis. In this study, we report for the first time a phospholipase complex composed of PLC-gamma1 and phospholipase D2 (PLD2). PLC-gamma1 is co-immunoprecipitated with PLD2 in COS-7 cells. The results of in vitro binding analysis and co-immunoprecipitation analysis in COS-7 cells show that the Src homology (SH) 3 domain of PLC-gamma1 binds to the proline-rich motif within the Phox homology (PX) domain of PLD2. The interaction between PLC-gamma1 and PLD2 is EGF stimulation-dependent and potentiates EGF-induced inositol 1,4,5-trisphosphate (IP(3)) formation and Ca(2+) increase. Mutating Pro-145 and Pro-148 within the PX domain of PLD2 to leucines disrupts the interaction between PLC-gamma1 and PLD2 and fails to potentiate EGF-induced IP(3) formation and Ca(2+) increase. However, neither PLD2 wild type nor PLD2 mutant affects the EGF-induced tyrosine phosphorylation of PLC-gamma1. These findings suggest that, upon EGF stimulation, PLC-gamma1 directly interacts with PLD2 and this interaction is important for PLC-gamma1 activity.

Although the functional significance of neuronal phospholipase D (PLD) is being recognized, little is known about its regulatory role in neuronal cells. To elucidate the regulatory mechanism of neuronal PLD, we investigated PLD(2)-binding neuronal protein from rat brain cytosol. During the fractionation of rat brain cytosol by four-column chromatography, a 62-kDa PLD(2)-interacting protein was detected by PLD(2) overlay assay and identified as collapsin response mediator protein-2 (CRMP-2), which controls neuronal axon guidance and outgrowth. Using bacterially expressed glutathione S-transferase fusion proteins, we found that two regions (amino acids 65-192 (the phagocytic oxidase domain) and 724-825) of PLD(2) and a single region (amino acids 243-300) of CRMP-2 are required for the direct binding of both proteins. A co-immunoprecipitation study in COS-7 cells also showed an in vivo interaction between CRMP-2 and PLD(2). Interestingly, CRMP-2 was found to potently inhibit PLD(2) activity in a concentration-dependent manner (IC(50) = 30 nm). Overexpression studies also showed that CRMP-2 is an in vivo inhibitor of PLD(2) in PC12 cells. Moreover, increasing the concentration of semaphorin 3A, one of the repulsive axon guidance cues, showed that PLD(2) activity can be inhibited in PC12 cells. Immunocytochemistry further revealed that PLD(2) is co-localized with CRMP-2 in the distal tips of neurites, its possible action site, in differentiated PC12 cells. Taken together, our results indicate that CRMP-2 may interact directly with and inhibit neuronal PLD(2), suggesting that this inhibitory mode of regulation may play a role in neuronal pathfinding during the developmental stage.

Gremlin-1, a bone morphogenetic protein (BMP) antagonist, is overexpressed in various cancerous tissues but its role in carcinogenesis has not been established. Here, we report that gremlin-1 binds various cancer cell lines and this interaction is inhibited by our newly developed gremlin-1 antibody, GRE1. Gremlin-1 binding to cancer cells was unaffected by the presence of BMP-2, BMP-4, and BMP-7. In addition, the binding was independent of vascular endothelial growth factor receptor-2 (VEGFR2) expression on the cell surface. Addition of gremlin-1 to A549 cells induced a fibroblast-like morphology and decreased E-cadherin expression. In a scratch wound healing assay, A549 cells incubated with gremlin-1 or transfected with gremlin-1 showed increased migration, which was inhibited in the presence of the GRE1 antibody. Gremlin-1 transfected A549 cells also exhibited increased invasiveness as well as an increased growth rate. These effects were also inhibited by the addition of the GRE1 antibody. In conclusion, this study demonstrates that gremlin-1 directly interacts with cancer cells in a BMP- and VEGFR2-independent manner and can induce cell migration, invasion, and proliferation.