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Possible Involvement (possible + involvement)
Selected AbstractsHEMOLYTIC ACTIVITY OF HETEROCAPSA CIRCULARISQUAMA (DINOPHYCEAE) AND ITS POSSIBLE INVOLVEMENT IN SHELLFISH TOXICITYJOURNAL OF PHYCOLOGY, Issue 4 2001Tatsuya Oda Heterocapsa circularisquama Horiguchi is lethal to shellfish, particularly bivalves such as pearl oysters (Pinctada fucata Gould). No detrimental effects of this flagellate on fish have been observed thus far. In this study, we found that H. circularisquama causes mammalian erythrocytes to lyse. Among the erythrocytes tested, rabbit erythrocytes showed the highest susceptibility, whereas erythrocytes from cattle, sheep, and human were relatively insensitive. Heterocapsa triquetra Stein, which is morphologically similar to H. circularisquama but not toxic to bivalves, showed no hemolytic activity toward rabbit erythrocytes. Culture supernatant or ultrasonic-ruptured cells of H. circularisquama showed only weak hemolytic activity. Hemolytic activity was found in the ethanol extract of H. circularisquama cells, suggesting that the hemolytic agents may be more stable in ethanol than in aqueous solution. Both an intact flagellate cell suspension and the ethanol extract caused morphological changes and eventual collapse of unfertilized eggs of Pacific oyster. Furthermore, the ethanol extract was lethal to the microzooplankton rotifer Brachionus plicatilis Müller, which is highly sensitive to H. circularisquama. Our results suggest that a hemolytic toxin produced by H. circularisquama may be one of the causative agents responsible for the shellfish toxicity. [source] Possible Involvement of I,B Kinase 2 and MKK7 in Osteoclastogenesis Induced by Receptor Activator of Nuclear Factor ,B Ligand,JOURNAL OF BONE AND MINERAL RESEARCH, Issue 4 2002Aiichiro Yamamoto Abstract Recent studies have revealed the essential role of the receptor activator of nuclear factor ,B (NF-,B) ligand (RANKL) in osteoclast differentiation and activation. Adenovirus vector could efficiently transduce genes into RAW264.7 cells, which differentiate into osteoclast-like multinucleated cells in the presence of RANKL. The role of NF-,B and c- jun N-terminal kinase (JNK) activation in RANKL-induced osteoclast differentiation was investigated using an adenovirus vector carrying the dominant negative I,B kinase 2 gene (AxIKK2DN) or dominant negative MKK7 gene (AxMKK7DN). IKK2DN and MKK7DN overexpression in RAW cells specifically suppressed the NF-,B activation and JNK activation in response to RANKL, respectively, without affecting other signaling pathways. Either inhibition of NF-,B or JNK pathways dose-dependently inhibited osteoclast formation induced by RANKL. These results suggest that both NF-,B and JNK activation are independently required for osteoclast differentiation. [source] A Mechanism of Vasodilatory Action of Polyamines and Acetylpolyamines: Possible Involvement of their Ca2+ Antagonistic PropertiesJOURNAL OF PHARMACY AND PHARMACOLOGY: AN INTERNATI ONAL JOURNAL OF PHARMACEUTICAL SCIENCE, Issue 6 2000CHANG-SEON MYUNG Polyamines, a class of low-molecular weight organic polycations, have been shown to produce relaxing effects in vascular smooth muscles, although the mechanism has not been carefully examined. In this study, the mechanism of vascular action of polyamines and their metabolites, acetylpolyamines, was pharmacologically examined in the rabbit isolated thoracic aorta focusing on an endothelium-dependent component of vasodilatation and Ca2+ influx through plasma membrane channels. Both polyamines and acetylpolyamines (except N1 -acetylputrescine, which produced no response or very slight contraction) caused concentration-dependent relaxation in pre-constricted aortic rings containing an intact endothelium. Aortic rings denuded of endothelium were also responsive to both polyamines and acetylpolyamines. Inhibitors of nitric oxide (reduced haemoglobin and N, -nitro- l -arginine methyl ester), vasodilator prostaglandins (indomethacin) and guanylyl cyclase (methylene blue) did not affect the relaxation induced by both polyamines and acetylpolyamines in either endothelium-intact or -denuded aortic rings. Both polyamines and acetylpolyamines inhibited the concentration-dependent contraction for phenylephrine and K+. The Ca2+ agonist Bay K 8644 induced concentration-dependent contraction in segments of rabbit aorta partially depolarized with 15 mm KCl, and both polyamines and acetylpolyamines relaxed the Bay K 8644-induced contraction in a concentration-dependent manner. Interestingly, both polyamines and acetylpolyamines also decreased contractions evoked by the Ca2+ ionophore A23187. The concentration-response curve to exogenous Ca2+ in K+ -depolarization medium (K+ = 120 mm) was shifted to the right by both polyamines and acetylpolyamines. The response elicited by Ca2+ was increased by Bay K 8644 (10,6m), and this potentiation was also inhibited by both polyamines and acetylpolyamines. The results indicate that both polyamines and acetylpolyamines can induce vasorelaxation of rabbit thoracic aorta by an endothelium-independent mechanism in-vitro and relax vascular smooth muscle by acting at the plasma membrane level, decreasing the influx of Ca2+. Therefore, polyamines and acetylpolyamines may have Ca2+ antagonistic properties which may, in part, be involved in the mechanism of rabbit aortic vascular smooth muscle relaxation. [source] Analysis of Gene Expression in Parkinson's Disease: Possible Involvement of Neurotrophic Support and Axon Guidance in Dopaminergic Cell DeathBRAIN PATHOLOGY, Issue 1 2009Koen Bossers Abstract Parkinson's disease (PD) is a neurodegenerative disorder characterized by the progressive loss of dopaminergic neurons in the substantia nigra. We have studied alterations in gene expression in the substantia nigra, the caudate nucleus and putamen of four PD patients and four matched controls using custom designed Agilent microarrays. To gain insight into changes in gene expression during early stages of dopaminergic neurodegeneration, we selectively investigated the relatively spared parts of the PD substantia nigra, and correlated gene expression changes with alterations in neuronal density. We identified changes in the expression of 287 transcripts in the substantia nigra, 16 transcripts in the caudate nucleus and four transcripts in the putamen. For selected transcripts, transcriptional alterations were confirmed with qPCR on a larger set of seven PD cases and seven matched controls. We detected concerted changes in functionally connected groups of genes. In the PD substantia nigra, we observed strong evidence for a reduction in neurotrophic support and alterations in axon guidance cues. As the changes occur in relatively spared parts of the PD substantia nigra, they suggest novel disease mechanisms involving neurotrophic support and axon guidance in early stages of cellular stress events, ultimately leading to dopaminergic cell death in PD. [source] Possible involvement of epidermodysplasia verruciformis human papillomaviruses in the immunopathogenesis of psoriasis: a proposed hypothesisEXPERIMENTAL DERMATOLOGY, Issue 6 2003Slawomir Majewski Abstract:, We have shown previously in psoriasis a very high prevalence of epidermodysplasia verruciformis-associated human papillomavirus 5 (EVHPV5) DNA and antibodies to human papillomavirus 5 (HPV5) virus-like particle (VLP)L1, and we suggested that this benign hyperproliferative disorder could be a reservoir for EVHPVs. Here we provide new data confirming the expression of EVHPVs in psoriasis and present our hypothesis on their possible involvement in the immunopathogenesis of the disorder. The new important finding was detection by a radioimmunoprecipitation assay of a very high prevalence of antibodies to E6/E7 HPV5 oncoproteins, known to enhance keratinocyte proliferation. More recently, EV genes were identified, EVER1 and EVER2, whose mutations are responsible for epidermodysplasia verruciformis. Epidermodysplasia verruciformis-associated human papillomaviruses are harmless to the general population as a result of genetic restriction, which in psoriasis appears to be partly alleviated, and this may allow the viral gene expression. We hypothesize that induction of keratinocyte proliferation in psoriasis by various stimuli initiates the EVHPV life cycle with expression of early (E6/E7) and late (L1) viral proteins. The early proteins may, in turn, enhance the keratinocyte proliferation, and the late proteins could serve as a target for specific B- and T-cell-mediated responses. Immune responses against the viral antigens in the epidermis may result in chemoattraction of leukocytes and Munro abscess formation, as well as in production of proinflammatory cytokines, leading to self perpetuation of the psoriatic process. The novel immunomodulatory therapies could also inhibit immune responses against EVHPV proteins, leading to decreased cytokine production, keratinocyte proliferation and EVHPV expression. Thus the beneficial effect of these therapies is not discordant with the proposed hypothesis of possible involvement of EVHPVs in the immunopathogenesis of psoriasis. [source] Possible involvement of an FKBP family member protein from a psychrotrophic bacterium Shewanella sp.FEBS JOURNAL, Issue 7 2004SIB1 in cold-adaptation A psychrotrophic bacterium Shewanella sp. strain SIB1 was grown at 4 and 20 °C, and total soluble proteins extracted from the cells were analyzed by two-dimensional polyacrylamide gel electrophoresis. Comparison of these patterns showed that the cellular content of a protein with a molecular mass of 28 kDa and an isoelectric point of four greatly increased at 4 °C compared to that at 20 °C. Determination of the N-terminal amino acid sequence, followed by the cloning and sequencing of the gene encoding this protein, revealed that this protein is a member of the FKBP family of proteins with an amino acid sequence identity of 56% to Escherichia coli FKBP22. This protein was overproduced in E. coli in a His-tagged form, purified, and analyzed for peptidyl-prolyl cis-trans isomerase activity. When this activity was determined by the protease coupling assay using N -succinyl-Ala-Leu-Pro-Phe- p -nitroanilide as a substrate at various temperatures, the protein exhibited the highest activity at 10 °C with a kcat/Km value of 0.87 µm,1·s,1. When the peptidyl-prolyl cis-trans isomerase activity was determined by the RNase T1 refolding assay at 10 and 20 °C, the protein exhibited higher activity at 10 °C with a kcat/Km value of 0.50 µm,1·s,1. These kcat/Km values are lower but comparable to those of E. coli FKBP22. We propose that a FKBP family protein is involved in cold-adaptation of psychrotrophic bacteria. [source] Possible involvement of GABAergic modulation in the protective effect of gabapentin against immobilization stress-induced behavior alterations and oxidative damage in miceFUNDAMENTAL & CLINICAL PHARMACOLOGY, Issue 6 2007Anil Kumar Abstract Introduction Acute stress may be experienced in response to an immediate physical, emotional or psychological stimulus. Stress has been known to affect several brain activities and promote long-term changes in multiple neural systems. In the present study, we investigated the possible involvement of GABAergic modulation in the protective effect of gabapentin in acute immobilization-induced behavioral alterations and oxidative damage in mice. Materials and methods Mice were immobilized for periods of 6 h. Animals were divided into different groups, consisting of six in each. Various GABAergic modulators were administered either alone or in their combinations, 30 min before subjecting the animals for immobilization stress. Various behavioral tests (mirror chamber, actophotometer) followed by oxidative parameters (malondialdehyde level, glutathione, catalase, nitrite and protein) were assessed in animals. Results Six hours acute immobilization stress caused significant locomotor impairment, anxiety-like behavior in mice. Biochemical analyses also revealed an increase malondialdehyde, nitrite level and depletion of glutathione and catalase activity in 6 h stressed brains. Pretreatment with gabapentin (50 and 100 mg/kg, i.p.) significantly improved ambulatory movements, anti-anxiety effect (decreased time latency to enter in mirror chamber, increased number of entries and duration in mirror chamber) and antioxidative activity in stressed mice (P < 0.05). Further, picrotoxin (1.0 mg/kg) blocked and muscimol (0.05 mg/kg) potentiated the protective action of gabapentin (50 mg/kg). Results of both behavior as well as biochemical alterations in combination studies were significant as compared to their effect per se (P < 0.05). Conclusion Results of present study suggest GABAergic modulation might be involved in the protective effect of gabapentin against immobilization-induced behavior alteration and oxidative damage in mice. [source] NG2 proteoglycan-expressing cells of the adult rat brain: Possible involvement in the formation of glial scar astrocytes following stab woundGLIA, Issue 3 2005G. Alonso Abstract Stab wound lesion to the adult central nervous system induces strong proliferative response that is followed by the formation of a dense astroglial scar. In order to determine the origin of those astrocytes composing the glial scar, the cell proliferation marker bromodeoxyuridine (BrdU) was administered to lesioned rats that were fixed 3 h or 6 days later. At 3 h after the BrdU administration, labeled nuclei were frequently associated with either NG2+ cells or microglia/macrophages, but rarely with astrocytes expressing glial fibrillary acidic protein (GFAP). Six days later, by contrast, numerous BrdU-labeled nuclei were associated with astrocytes located along the lesion borders. After the injection of a viral vector of the green fluorescent protein (GFP) into the lesional cavity, GFP was preferentially detected within NG2- or GFAP-labeled cells when lesioned animals were fixed 1 or 6 days after the injections, respectively. The combined detection of glial markers within cells present in the lesioned area indicated that, although they rarely express GFAP, the marker of mature astrocytes, NG2+ cells located along the lesion borders frequently express nestin and vimentin, i.e., two markers of immature astrocytes. Lastly, chronic treatment of lesioned rats with dexamethasone was found to inhibit the proliferation of NG2+ cells present within the lesioned area and to subsequently alter the formation of a dense astroglial scar. Taken together, these data strongly suggest that following a surgical lesion, at least a portion of the astrocytes that constitute the glial scar are issued from resident NG2+ cells. © 2004 Wiley-Liss, Inc. [source] Possible involvement of protein kinase C in the induction of adipose differentiation-related protein by Sterol ester in RAW 264.7 macrophagesJOURNAL OF CELLULAR BIOCHEMISTRY, Issue 2 2001Jin-Shan Chen Abstract The accumulation of lipid droplets in macrophages contributes to the formation of foam cells, an early event in atherosclerosis. It is, therefore, important to elucidate the mechanisms by which lipid droplets accumulate and are utilized. Sterol ester (SE)-laden RAW 264.7 macrophages accumulated lipid droplets in a time-dependent manner up to 16 h, which was enhanced by cotreatment with 0.1 ,M phorbol 12-myristate 13-acetate (PMA). Inhibition of protein kinase C (PKC) activity by cotreatment with 0.3 ,M calphostin C CAL for 16 h resulted in coalescence of small lipid droplets into large ones and increased accumulation of lipid droplets, although to a lesser extent than after PMA cotreatment. Immunostaining for adipose differentiation-related protein (ADRP) revealed a fluorescent rim at the surface of each medium to large lipid droplet. ADRP appearance correlated with lipid droplet accumulation and was regulated by PMA in a time-dependent manner. Induction of ADRP expression by PMA or CAL required SE, since ADRP levels in PMA- or CAL-treated non-SE-laden macrophages were comparable to those in untreated cells. Removal of SE from the incubation medium resulted in the concomitant dissolution of lipid droplets and down-regulation of ADRP. In conclusion, the above results suggest that ADRP may be an important protein in the regulation of lipid droplet metabolism in lipid-laden macrophages and that this regulation may be mediated by PKC activity. J. Cell. Biochem. 83: 187,199, 2001. © 2001 Wiley-Liss, Inc. [source] Possible involvement in oncogenesis of a single base mutation in an internal ribosome entry site of Epstein,Barr nuclear antigen 1 mRNAJOURNAL OF MEDICAL VIROLOGY, Issue 4 2004Rika Endo Abstract It has been reported recently that the U leader exon located within the 5, untranslated region of Epstein,Barr nuclear antigen 1 (EBNA1) gene contains an internal ribosome entry site (IRES) element. Sequence analysis of the U leader exon was undertaken in samples from 19 patients with infectious mononucleosis and 19 patients with lethal lymphoproliferative diseases and in 15 spontaneously established lymphoblastoid cell lines. The sequence was conserved except for a single base substitution (T-C) at position 67,585. Although the mutation was detected in only one case of infectious mononucleosis, it was found in more than half of the lethal lymphoproliferative diseases and all lymphoblastoid cell lines. The results suggest that a mutation in the IRES element affects EBNA1 gene expression at the translational level and provides Epstein,Barr virus (EBV)-infected cells with a growth advantage, leading to immortalization of cells in vitro and to the development of lethal lymphoproliferative diseases in vivo. J. Med. Virol. 72:630,634, 2004. © 2004 Wiley-Liss, Inc. [source] ,2A -Adrenergic Receptor Signaling Underlies Synergistic Enhancement of Ethanol-Induced Behavioral Impairment by ClonidineALCOHOLISM, Issue 3 2009Tara Summer Bender Background:, We tested the hypothesis that central ,2A -adrenergic receptor (,2AAR) signaling plays a key role in clonidine-ethanol evoked synergistic behavioral impairment. Methods:, Male Sprague-Dawley rats, with intracisternal and jugular vein cannulae implanted 6 days earlier, were tested for drug-induced behavioral impairment. The latter was assessed as the duration of loss of righting reflex (LORR) and rotorod performance every 15 minutes until the rat recovered to the baseline walk criterion (180 seconds). In a separate cohort, c-Fos expression in locus coeruleus (LC) and cerebellum was determined as a marker of neuronal activity following drug treatment. Results:, Rats that received clonidine (60 ,g/kg, i.v.) followed by ethanol (1 g/kg, i.v.) exhibited synergistic impairment of rotorod performance and LORR. The mixed ,2AAR and I1 -imidazoline receptor agonist clonidine (30, 60, and 90 ,g/kg) synergistically and dose-dependently enhanced behavioral impairment elicited by ethanol (1 g/kg). Possible involvement of I1 -imidazoline receptors was ruled out because selective I1 -agonist rilmenidine (300 ,g/kg, i.v.) did not cause behavioral impairment alone or enhance ethanol-evoked behavioral impairment. Pharmacological blockade of central ,2AAR (RX821002, 0.3 mg i.c.) abolished the synergy between clonidine and ethanol; the behavioral response caused by the drug combination was similar to that caused by ethanol alone. Conversely, involvement of central ,2BAR in the interaction was ruled out because blockade of central ,2BAR (ARC-239) independently evoked a strong sedative effect. Clonidine (60 ,g/kg) or ethanol (1 g/kg) alone increased, but their combination decreased, c-Fos levels in LC, while inconsistent c-Fos responses were observed in cerebellum. Conclusions:, Central ,2AAR, but not I1 -imidazoline or ,2BAR, signaling is implicated in the synergistic enhancement of ethanol-evoked behavioral impairment by clonidine. Although the mechanism of c-Fos response remains to be investigated, this neurochemical response highlights the LC as a neuroanatomical target for clonidine-ethanol behavioral interaction. [source] Possible involvement of phosphatidylinositol 3-kinase in the maintenance of metaphase II attest in porcine oocytes matured in vitroANIMAL SCIENCE JOURNAL, Issue 1 2010Junya ITO ABSTRACT It has been reported that phosphatidylinositol 3-kinase (PI3K)-protein kinase B (PKB) pathway plays a crucial role in the meiotic resumption and progression to the metaphase II (MII) stage of oocytes. However, the role of this pathway in meiotic arrest at the MII stage (cytostatic activity) is not well understood. In this study the effect of a PI3K inhibitor, LY294002, on the MAPK and p34cdc2 kinase activities of matured porcine oocytes was examined. After maturation culture, both the MAPK and p34cdc2 kinase activities in the oocytes were gradually decreased in a time-dependent manner. Although 25 µmol/L LY294002 did not affect either the MAPK or p34cdc2 kinase activities, 50 µmol/L LY294002 suppressed the PKB phosphorylation and slightly decreased MAPK activity, but not the p34cdc2 kinase activity. Therefore the effect of 10 µmol/L Ca2+ ionophore which was reported as inducing a transient decrease of p34cdc2 kinase but not MAPK activities, was also examined in LY294002-treated oocytes. By additional treatment with LY294002 after Ca2+ ionophore, both the MAPK and p34cdc2 kinase activities were decreased in a time-dependent manner, concomitantly with improvement of pronuclear formation. Therefore, we concluded that PI3K is involved in the maintenance of MAPK activity in matured porcine oocytes. [source] Possible involvement of endothelium-derived hyperpolarizing factor (EDHF) in the depressor responses to platelet activating factor (PAF) in ratsBRITISH JOURNAL OF PHARMACOLOGY, Issue 6 2000Yoshio Tanaka In anaesthetized rats, platelet activating factor (PAF; 1 ,g kg,1) decreased mean arterial blood pressure by around 60 mmHg (n=18). This depressor response was completely blocked by the PAF antagonist, CV-6209 (1 mg kg,1), indicating the role of PAF-specific receptor in the response. NG -nitro- L -arginine methyl ester (L -NAME; 50 mg kg,1), an NO synthase inhibitor, profoundly elevated systemic blood pressure (n=19), indicating an important role of NO in the basal blood pressure regulation. The depressor response to PAF (1 ,g kg,1) normalized against that to sodium nitroprusside (SNP) (10 ,g kg,1) was not substantially different between rats treated without and with L -NAME (n=4). In contrast, the depressor effect of acetylcholine (0.03,1.0 ,g kg,1) normalized against that of SNP (10 ,g kg,1) was significantly attenuated by L -NAME (n=5). Charybdotoxin (0.4 mg kg,1) plus apamin (0.2 mg kg,1) significantly attenuated the depressor response to PAF (1 ,g kg,1) (n=5) without affecting the blood pressure change due to SNP (1 mg kg,1) (n=3). Charybdotoxin (0.4 mg kg,1) (n=4) or apamin (0.2 mg kg,1) (n=4) alone did not affect the PAF-induced depressor response. These findings suggest that EDHF may make a significant contribution to the depressor response to PAF in rats. Although NO plays the determinant role in the basal blood pressure regulation, its contribution to PAF-produced depressor response seems to be less as compared with that to the depressor response to acetylcholine. British Journal of Pharmacology (2000) 131, 1113,1120; doi:10.1038/sj.bjp.0703681 [source] Strong HLA-DR antigen expression on cancer cells relates to better prognosis of colorectal cancer patients: Possible involvement of c-myc suppression by interferon-,in situCANCER SCIENCE, Issue 1 2006Kazuyuki Matsushita Strong HLA-DR antigen expression on cancer cells relates to better prognosis of colorectal cancer patients, although the precise mechanism is controversial. From an immunological point of view, HLA-DR antigen, induced by interferon (IFN)-,, is required for tumor-associated antigen recognition by CD4+ T cells. For instance, as reported previously, the expression of HLA-DR antigen in normal colorectal epithelium immediately adjacent to cancer coincided significantly with the existence of IFN-, mRNA in the tissue. From another aspect, IFN-, has been revealed to suppress c-myc expression in vivo through a stat1-dependent mechanism, which is important for cell growth, cell cycle and chromosome instability. In the present study, strong HLA-DR-positive expression on cancer cells was significantly related to better prognosis for colorectal cancer patients. High IFN-, mRNA expression in situ indicated significantly less activation of c-myc mRNA expression. Further, HLA-DR antigen expression in cancer cells, as well as Dukes stages, was an independent factor for better long-term survival by multivariate analysis. Taken together, IFN-,, which induces HLA-DR antigens on the cell surface, also suppresses c-myc expression in situ, and is a possible non-immunological mechanism involved in the better long-term survival of colorectal cancer patients. (Cancer Sci 2006; 97: 57, 63) [source] Induction of apoptosis by A3 adenosine receptor agonist N6 -(3-iodobenzyl)-adenosine-5,- N -methylcarboxamide in human leukaemia cells: a possible involvement of intracellular mechanismACTA PHYSIOLOGICA, Issue 2 2010P. Mlejnek Abstract Aim:, The sensitivity of cancer cells which exhibit multi-drug resistance phenotype to A3 adenosine receptor (A3AR) agonist N6 -(3-iodobenzyl)-adenosine-5,- N -methylcarboxamide (IB-MECA) was studied. Methods:, To establish direct relationship between P-glycoprotein (P-gp, ABCB1 and MDR1) expression and IB-MECA induced cell death, a straightforward method for precise estimation of intracellular level of this A3AR agonist was developed. Results:, We subjected three human leukaemia cell lines HL-60, K562 and K562/HHT to treatment with micromolar concentrations of IB-MECA. Although all cell lines used expressed A3AR, there was a large difference in their sensitivity to IB-MECA. While HL-60 and K562 cells were almost equally sensitive, the K562/HHT cells, which exhibit a multi-drug resistance phenotype because of overexpression of P-gp, were significantly more resistant. We found that the intracellular level of IB-MECA in K562/HHT cells was approx. 10 times lower than those in HL-60 or K562 cells. Inhibitors of P-gp, including cyclosporine A (CsA) and verapamil (Vpa), increased the intracellular level of IB-MECA and reversed the resistance of K562/HHT cells to this drug. Accordingly, shRNA-mediated down-regulation of P-gp significantly increased the intracellular level of IB-MECA in K562/HHT cells which simultaneously exhibited reduced resistance to this A3AR agonist. In addition, an in vitro enzyme-based assay provided evidence that IB-MECA might serve as a substrate for P-gp. Conclusion:, Our results suggest that P-gp overexpression prevents cells from IB-MECA induced apoptosis despite the A3AR expression. Pro-apoptotic effect of IB-MECA seemed to strongly depend on its intracellular accumulation rather than on its interaction with A3AR. [source] Migration of mesenchymal cell fated to blastema is necessary for fish fin regenerationDEVELOPMENT GROWTH & DIFFERENTIATION, Issue 2 2008Yuki Nakatani Urodeles and fish have higher regeneration ability in a variety of tissues and organs than do other vertebrate species including mammals. Though many studies have aimed at identifying the cellular and molecular basis for regeneration, relatively little is known about the detailed cellular behaviors and involved molecular basis. In the present study, a small molecule inhibitor was used to analyzed the role of phosphoinositide 3-kinase (PI3K) signaling during regeneration. We showed that the inhibitor disrupted the formation of blastema including the expression of characteristic genes. The failure of blastema formation was due to the impaired migration of mesenchymal cells to the distal prospective blastema region, although it had a little affect on cell cycle activation in mesenchymal cells. Moreover, we found that the epidermal remodeling including cell proliferation, distal cell migration and Akt phosphorylation was also affected by the inhibitor, implying a possible involvement of epidermis for proper formation of blastema. From these data, we propose a model in which distinct signals that direct the cell cycle activation, mesenchymal cell migration and epidermal remodeling coordinate together to accomplish the correct blastema formation and regeneration. [source] Eph,ephrin A system regulates murine blastocyst attachment and spreadingDEVELOPMENTAL DYNAMICS, Issue 12 2006Haruko Fujii Abstract Although numerous adhesion molecules are expressed on mammalian endometrial epithelial cells, there have not been any studies of a mechanism to prevent premature attachment of the embryo. In this study, we examined the possible involvement of Eph,ephrin interaction, which can induce repulsive forces. In mice, Eph A1, A2, and A4 were expressed on endometrial epithelial cells and ephrin A1,4 on blastocysts. Reverse transcriptase-polymerase chain reaction showed that mRNA expression of ephrin A1,4 on embryos transiently decreased around the implantation period. Immunohistochemistry demonstrated that the expression of Eph A1 on endometrial epithelial cells and ephrin A1 and A3 expression on embryos decreased at implantation sites. Recombinant Eph A1 reacted with cell the surface of ephrin A-bearing trophectoderm cells. Attachment assays using Eph A1-coated dishes showed that blastocyst attachment was reversibly inhibited by Eph A1. These findings suggest an important role of the Eph,ephrin A system in regulating the initial embryo,maternal contact during the cross-talk period that precedes embryo implantation. Developmental Dynamics 235:3250,3258, 2006. © 2006 Wiley-Liss, Inc. [source] Morphogens and cell survival during developmentDEVELOPMENTAL NEUROBIOLOGY, Issue 4 2005Patrick Mehlen Abstract The notion of "morphogens" is an important one in developmental biology. By definition, a morphogen is a molecule that emanates from a specific set of cells that is present in a concentration gradient and that specifies the fate of each cell along this gradient. The strongest candidate morphogens are members of the transforming growth factor-, (TGF-,), Hedgehog (Hh), and Wnt families. While these morphogens have been extensively described as differentiation inducers, some reports also suggest their possible involvement in cell death and cell survival. It is frequently speculated that the cell death induction that is found associated with experimental removal of morphogens is the manifestation of abnormal differentiation signals. However, several recent reports have raised controversy about this death by default, suggesting that cell death regulation is an active process for shaping tissues and organs. In this review, we will present morphogens, with a specific emphasis on Sonic Hedgehog, a mammalian member of the Hh family, not as a positive regulators of cell differentiation but as key regulators of cell survival. © 2005 Wiley Periodicals, Inc. J Neurobiol 64: 357,366, 2005 [source] Human breast areolae as scent organs: Morphological data and possible involvement in maternal-neonatal coadaptationDEVELOPMENTAL PSYCHOBIOLOGY, Issue 2 2006Benoist Schaal Abstract In humans, areolar skin glands (AG) enlarge during pregnancy and lactation. Their role in mother-infant interactions may pertain to protective, mechanical, and communicative functions. It was questioned here whether more profuse AG could be related to more optimal adaptation to breastfeeding. A morphological study of the areolae was undertaken between birth and day 3 to assess the number, secretory status, and spatial distribution of AG. These data were related to infants' weight variation, mothers' perception of their infant's behavior at breast, and time between delivery and onset of lactation. AG were seen in virtually all women but with great interindividual variations; their areolar distribution was nonrandom, and about 1/5 of the women had AG giving off a secretion. The AG number was positively related with neonatal weight gain between birth and day 3, and with the mother's perception of infant's latching speed and sucking activity. AG numbers were also positively related with the onset of lactation in first-time mothers. In conclusion, the maternal endowment in AG may contribute to the infants' breastfeeding performance, early growth, and the mother's lactation onset. © 2006 Wiley Periodicals, Inc. Dev Psyshobiol 48: 100,110, 2006. [source] The nodPQ genes in Azospirillum brasilense Sp7 are involved in sulfation of lipopolysaccharidesENVIRONMENTAL MICROBIOLOGY, Issue 11 2005Els Vanbleu Summary Here we report on the presence of sulfated lipopolysaccharide molecules in Azospirillum brasilense, a plant growth-promoting rhizosphere bacterium. Chemical analysis provided structural data on the O-antigen composition and demonstrated the possible involvement of the nodPQ genes in O-antigen sulfation. [source] Cytotoxicity and oxidative stress caused by chemicals adsorbed on particulate matter,ENVIRONMENTAL TOXICOLOGY, Issue 5 2006Andrea Müller Abstract Air particulate matter (PM) and bound chemicals are potential mediators for adverse health effects. The cytotoxicity and changes in energy-providing processes caused by chemical compounds bound to PM of different size fractions were investigated in Tetrahymena pyriformis. The PM samplings were carried out using a high volume cascade impactor (6 size fractions between 10 ,m and less than 0.49 ,m) at three points of La Plata, Argentina: in an industrial area, a traffic-influenced urban area, and a control area. Extracts from respirable particles below 1 ,m initiated the highest cytotoxic effects, demonstrating their higher risk. In contrast, an increase on oxygen consumption was observed especially in tests of extracts from particles less than 1 ,m from urban and industrial areas. The increase on oxygen consumption could be caused by decoupling processes in the respiratory chain. Otherwise the ATP concentration was increased too, even though to a lower extent. The observed imbalance between oxygen consumption and ATP concentration in exposed T. pyriformis cells may be due to oxidative stress, caused by chemical compounds bound to the particles. Owing to the complexity of effects related to PM and their associated chemical compounds, various physiological parameters necessarily need to be investigated to obtain more information about their possible involvement in human relevant pathogenic processes. As shown here, effects on cell proliferation and on energy-providing processes are suitable indicators for the different impact of PM and adsorbed chemicals from various sampling locations. © 2006 Wiley Periodicals, Inc. Environ Toxicol 21: 457,463, 2006. [source] Altered Tryptophan Metabolism in the Brain of Cystatin B -Deficient Mice: A Model System for Progressive Myoclonus EpilepsyEPILEPSIA, Issue 10 2006Annika Vaarmann Summary:,Purpose: Progressive myoclonus epilepsy of the Unverricht,Lundborg type (EPM1) is a rare neurologic disorder, associated with mutations in the Cystatin B (Cstb) gene. Mice lacking Cstb, a cysteine protease inhibitor of the cathepsine family of proteases, provide a mammalian model for EPM1 by displaying similarly progressive ataxia, myoclonic seizures, and neurodegeneration. However, the linkage of Cstb deficit on the molecular level to pathologic features like myoclonic jerks or tonic,clonic seizures has remained unclear. We examined the tryptophan (TRP) metabolism, along the serotonin (5HT) and kynurenine (KYN) pathway in the brain of Cstb -deficient mice, in relation to their possible involvement in the seizure phenotype. Methods: TRP and its metabolites, along the 5HT and KYN pathways, were assayed in brain tissue by high-pressure liquid chromatography (HPLC) with electrochemical detection. The inverted wire grid and mild handling tests were used for evaluation of ataxia and myoclonic activity. Results: The Cstb -deficient mice had constitutively increased TRP, 5HT, and 5-hydroxyindole acetic acid (5HIAA) levels in the cerebral cortex and cerebellum and increased levels of KYN in the cerebellum. These neurochemical changes were accompanied with ataxia and an apparent myoclonic phenotype among the Cstb -deficient mice. Conclusions: Our findings suggest that secondary processes (i.e., overstimulation of serotoninergic transmission) on the cellular level, initiated by Cstb deficiency in specific brain regions, may be responsible for the myoclonic/seizure phenotype in EPM1. [source] Pathologic expression of MHC class,II is driven by mitogen-activated protein kinasesEUROPEAN JOURNAL OF IMMUNOLOGY, Issue 3 2007Isabelle Martins Abstract The class,II transactivator (CIITA) is the master regulator of MHC class,II molecules (MHC,II). In melanoma, the MHC,II are constitutively expressed due to an abnormal transcription of CIITA from its promoter,III (pIII), and requires the presence of a 1-kb enhancer located upstream from this latter. Since mitogen-activated protein kinases (MAPK) have been shown to be activated in most melanomas, we sought to analyze their possible involvement in CIITA expression. Using chemical inhibitors and dominant-negative constructs of MAPK-ERK kinase (Mek1) and MAPK-JNK, we evidenced the inhibition of MHC,II and CIITA expression in melanoma cell lines displaying activated MAPK. Transcriptional regulation by MAPK is known to involve the AP-1 transcription factor family. Sequence analysis revealed an AP-1-responsive motif in the enhancer of CIITA pIII at ,5954/,5947 from the site of transcription initiation. Its mutagenesis reduced CIITA expression four- to fivefold in melanoma cell lines and alleviated the effect of dominant-negative constructs of the MAPK pathway. Together, our findings demonstrate that MAPK-ERK and MAPK-JNK are regulators of CIITA transcription in melanoma, and pinpoint an AP-1-responsive site in the CIITA gene pIII. This should have considerable impact on our understanding of the physio-pathologic expression of MHC,II. [source] Differential expression of PKC beta II in the rat organ of CortiEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 10 2007S. Ladrech Abstract To investigate a possible involvement of protein kinase C (PKC) in cochlear efferent neurotransmission, we studied the expression of the calcium-dependent PKC beta II isoform in the rat organ of Corti at different postnatal ages using immunofluorescence and immunoelectron microscopy. We found evidence of PKC beta II as early as postnatal day (PND) 5 in efferent axons running in the inner spiral bundle and in Hensen cells. At PND 8, we also found PKC beta II in efferents targeting outer hair cells (OHCs), and a slight detection at the synaptic pole in the first row of the basal and middle cochlear turns. At PND 12, PKC beta II expression declined in the efferent fibres contacting OHCs, whereas expression was concentrated at the postsynaptic membrane, from the basal and middle turns. The adult-like pattern of PKC beta II distribution was observed at PND 20. Throughout the cochlea, we found PKC beta II expression in the Hensen cells, non-sensory cells involved in potassium re-cycling, and lateral efferent terminals of the inner spiral bundle. In addition, we observed expression in OHCs at the postsynaptic membrane facing the endings of the medial efferent system, with the exception of some OHCs located in the most apical region of the cochlea. These data therefore suggest an involvement of PKC beta II in both cochlear efferent neurotransmission and ion homeostasis. Among other functions, PKC beta II could play a role in the efferent control of OHC activity. [source] Neuropathic pain is enhanced in ,-opioid receptor knockout miceEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 3 2006Xavier Nadal Abstract We have evaluated the possible involvement of ,-opioid receptor (DOR) in the development and expression of neuropathic pain. For this purpose, partial ligation of the sciatic nerve was performed in DOR knockout mice and wild-type littermates. The development of mechanical and thermal allodynia, as well as thermal hyperalgesia was evaluated by using the von Frey filament model, the cold-plate test and the plantar test, respectively. In wild-type and DOR knockout mice, sciatic nerve injury led to a neuropathic pain syndrome revealed in these nociceptive behavioural tests. However, the development of mechanical and thermal allodynia, and thermal hyperalgesia was significantly enhanced in DOR knockout mice. These results reveal the involvement of DOR in the control of neuropathic pain and suggest a new potential therapeutic use of DOR agonists. [source] Pro-VGF-derived peptides induce penile erection in male rats: possible involvement of oxytocinEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 11 2004Salvatora Succu Abstract The effect of five peptides derived from the C-terminal portion of rat pro-VGF (VGF577-617, VGF588-617, VGF599-617, VGF556-576 and VGF588-597) on penile erection was studied after injection into the hypothalamic paraventricular nucleus of male rats. VGF577-617, VGF588-617, VGF599-617 and, to a lower extent, VGF588-597 (0.1,2 µg) induced penile erection episodes in a dose-dependent manner when injected into the paraventricular nucleus, while VGF556-576 was ineffective. VGF588-617 -induced penile erection was reduced by nitro, - l -arginine methylester (L-NAME; 20 µg), by morphine (5 µg) and by muscimol (1 µg), but not by dizocilpine [(+)MK-801; 1 µg], nor by cis -flupenthixol (10 µg) given into the paraventricular nucleus 10 min before the VGF peptide. d(CH2)5Tyr(Me)-Orn8 -vasotocin (1 µg) effectively reduced VGF588-617 -induced penile erection when given into the lateral ventricles but not when injected into the paraventricular nucleus. Immunocytochemistry with antibodies specific for the C-terminal nonapeptide sequence of pro-VGF (VGF609-617) revealed numerous neuronal fibres and terminals within the paraventricular nucleus, including its parvocellular components. Here, many immunostained neuronal terminals impinged on parvocellular oxytocinergic neurons. The present results show for the first time that certain pro-VGF C-terminus-derived peptides promote penile erection when injected into the paraventricular nucleus and suggest that, within this nucleus, these or closely related pro-VGF-derived peptides may be released to influence sexual function by activating paraventricular oxytocinergic neurons mediating penile erection. [source] Disabled-1 mRNA and protein expression in developing human cortexEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 3 2003Gundela Meyer Abstract Disabled-1 (Dab1) forms part of the Reelin,Dab1 signalling pathway that controls neuronal positioning during brain development; Dab1 deficiency gives rise to a reeler-like inversion of cortical layers. To establish a timetable of Dab1 expression in developing human brain, Dab1 mRNA and protein expression were studied in prenatal human cortex. The earliest Dab1 signal was detected at 7 gestational weeks (GW), the stage of transition from preplate to cortical plate, suggesting a role of the Reelin,Dab1 signalling pathway in preplate partition. From 12 to 20 GW, the period of maximum cortical migration, Dab1 expression was prominent in the upper tiers of the cortical plate, to decline after midgestation. Radially orientated apical dendrites of Dab1-expressing neurons indicated a predominant pyramidal phenotype. Pyramidal cells in hippocampus and entorhinal cortex displayed a more protracted time of Dab1 expression compared to neocortex. In addition, at later stages (18,25 GW), Dab1 was also expressed in large neurons scattered throughout intermediate zone and subplate. From 14 to 22 GW, particularly high levels of Dab1 mRNA and protein were observed in cells of the ventricular/subventricular zone displaying the morphology of radial glia. The partial colocalization of vimentin and Dab1 in cells of the ventricular zone supported a radial glia phenotype. The concentration of Dab1 protein in ventricular endfeet and initial portions of radial processes of ventricular-zone cells points to a possible involvement of Dab1 in neurogenesis. Furthermore, a subset of Cajal,Retzius cells in the marginal zone colocalized Dab1 and Reelin, and may thus represent a novel target of the Reelin,Dab1 signalling pathway. [source] Molecular analyses of the candidate tumor suppressor gene, PLAGL1, in benign and malignant salivary gland tumorsEUROPEAN JOURNAL OF ORAL SCIENCES, Issue 6 2004Fredrik Enlund Deletions affecting the long arm of chromosome 6 are a characteristic feature of all major subtypes of malignant salivary gland tumors. Moreover, a subgroup of adenoid cystic carcinomas have t(6;9)(q23-25;p21-24) translocations with breakpoints located within the commonly deleted region. Here we have examined the possible involvement of the candidate tumor suppressor gene, PLAGL1, in these deletions and translocations. Northern blot and fluorescence in situ hybridization (FISH) analyses of a series of 27 salivary gland tumors revealed no significant changes in the gene expression or rearrangements of PLAGL1. FISH analysis also demonstrated that the 6q translocation breakpoint in adenoid cystic carcinomas with t(6;9) is proximal to the PLAGL1 locus. Collectively, these results indicate that PLAGL1 is not likely to be the major target gene of the 6q rearrangements in salivary gland tumors. [source] Possible involvement of epidermodysplasia verruciformis human papillomaviruses in the immunopathogenesis of psoriasis: a proposed hypothesisEXPERIMENTAL DERMATOLOGY, Issue 6 2003Slawomir Majewski Abstract:, We have shown previously in psoriasis a very high prevalence of epidermodysplasia verruciformis-associated human papillomavirus 5 (EVHPV5) DNA and antibodies to human papillomavirus 5 (HPV5) virus-like particle (VLP)L1, and we suggested that this benign hyperproliferative disorder could be a reservoir for EVHPVs. Here we provide new data confirming the expression of EVHPVs in psoriasis and present our hypothesis on their possible involvement in the immunopathogenesis of the disorder. The new important finding was detection by a radioimmunoprecipitation assay of a very high prevalence of antibodies to E6/E7 HPV5 oncoproteins, known to enhance keratinocyte proliferation. More recently, EV genes were identified, EVER1 and EVER2, whose mutations are responsible for epidermodysplasia verruciformis. Epidermodysplasia verruciformis-associated human papillomaviruses are harmless to the general population as a result of genetic restriction, which in psoriasis appears to be partly alleviated, and this may allow the viral gene expression. We hypothesize that induction of keratinocyte proliferation in psoriasis by various stimuli initiates the EVHPV life cycle with expression of early (E6/E7) and late (L1) viral proteins. The early proteins may, in turn, enhance the keratinocyte proliferation, and the late proteins could serve as a target for specific B- and T-cell-mediated responses. Immune responses against the viral antigens in the epidermis may result in chemoattraction of leukocytes and Munro abscess formation, as well as in production of proinflammatory cytokines, leading to self perpetuation of the psoriatic process. The novel immunomodulatory therapies could also inhibit immune responses against EVHPV proteins, leading to decreased cytokine production, keratinocyte proliferation and EVHPV expression. Thus the beneficial effect of these therapies is not discordant with the proposed hypothesis of possible involvement of EVHPVs in the immunopathogenesis of psoriasis. [source] Definition of the residues required for the interaction between glycine-extended gastrin and transferrin in vitroFEBS JOURNAL, Issue 17 2009Suzana Kovac Transferrin is the main iron transport protein found in the circulation, and the level of transferrin saturation in the blood is an important indicator of iron status. The peptides amidated gastrin(17) (Gamide) and glycine-extended gastrin(17) (Ggly) are well known for their roles in controlling acid secretion and as growth factors in the gastrointestinal tract. Several lines of evidence, including the facts that transferrin binds gastrin, that gastrins bind ferric ions, and that the level of expression of gastrins positively correlates with transferrin saturation, suggest the possible involvement of the transferrin,gastrin interaction in iron homeostasis. In the present work, the interaction between gastrins and transferrin has been characterized by surface plasmon resonance and covalent crosslinking. First, an interaction between iron-free apo-transferrin and Gamide or Ggly was observed. The fact that no interaction was observed in the presence of the chelator EDTA suggested that the gastrin,ferric ion complex was the interacting species. Moreover, removal of ferric ions with EDTA reduced the stability of the complex between apo-transferrin and gastrins, and no interaction was observed between Gamide or Ggly and diferric transferrin. Second, some or all of glutamates at positions 8,10 of the Ggly molecule, together with the C-terminal domain, were necessary for the interaction with apo-transferrin. Third, monoferric transferrin mutants incapable of binding iron in either the N-terminal or C-terminal lobe still bound Ggly. These findings are consistent with the hypothesis that gastrin peptides bind to nonligand residues within the open cleft in each lobe of transferrin and are involved in iron loading of transferrin in vivo. Structured digital abstract ,,MINT-7212832, MINT-7212849: Apo-transferrin (uniprotkb:P02787) and Gamide (uniprotkb:P01350) bind (MI:0407) by surface plasmon resonance (MI:0107) ,,MINT-7212881, MINT-7212909: Ggly (uniprotkb:P01350) and Apo-transferrin (uniprotkb:P02787) bind (MI:0407) by cross-linking studies (MI:0030) ,,MINT-7212864: Apo-transferrin (uniprotkb:P02787) and Ggly (uniprotkb:P01350) bind (MI:0407) by competition binding (MI:0405) [source] | |||||||||||||||||||||||||||||||||||||