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Annexin II (annexin + ii)
Selected AbstractsExpression of a releasable form of annexin II by human keratinocytesJOURNAL OF CELLULAR BIOCHEMISTRY, Issue 4 2002Feridoun Karimi-Busheri Abstract Annexin II is a multifunctional calcium-dependent phospholipid binding protein whose presence in epidermis has previously been reported. However, like other members of annexin family, annexin II has been regarded as either an intracellular protein or associated with the cellular membrane. Here, we report the presence of a releasable annexin II and p11, two monomers of annexin II tetramer, in keratinocyte-conditioned medium (KCM). Proteins present in KCM were fractionated on a gel filtration column and following further evaluation, a releasable protein with apparent MW of 36 kDa was identified. Further characterization identified this protein as the p36 monomer of annexin II tetramer. The phospho-tyrosine antibody did not visualize this protein as the phosphorylated form of p36. Several experiments were conducted to examine whether this protein is soluble or associated with keratinocyte cell membranes in the conditioned medium. A centrifugation of conditioned medium was not able to bring this protein down into the pellet. Surprisingly, the results of Western analysis identified p36 and p11, two monomers of the annexin II tetramer, in conditioned medium derived from either keratinocytes cultured alone or keratinocytes co-cultured with fibroblasts. In contrast to the keratinocyte-conditioned medium in which annexin II was easily detectable, both monomers were barely detectable in conditioned medium collected from dermal fibroblasts. This finding was in contrast to the cell lysates in which p36 was detectable in both keratinocytes and fibroblasts. However, the amount of this protein was markedly higher in keratinocyte lysate relative to that of dermal fibroblasts. Conditioned medium derived from keratinocyte established from adult showed a higher level of annexin II compared to that of keratinocytes established from newborn babies. The expression of p11 seems to increase with differentiation of keratinocytes derived from either adult or newborn skin samples. When the site of annexin synthesis in human skin was examined by immunohistochemical staining, the antibody for p36 localized the annexin to the keratinocyte cell members in the basal and suprabasal keratinocytes. In conclusion, Western blot detection of both p36 and p11 in conditioned medium from skin cells revealed that human keratinocytes, but not fibroblasts, express a releasable monomer form of annexin II which is regulated by differentiation status of keratinocytes. This finding is consistent with the localization of annexin II detected by immunohistochemical staining. J. Cell. Biochem. 86: 737,747, 2002. © 2002 Wiley-Liss, Inc. [source] Hypoxia-like effect of Cobalt Chromium alloy micro particles on fibroblasts in vitroJOURNAL OF ORTHOPAEDIC RESEARCH, Issue 10 2010Bernadette K. Madathil Abstract Periprosthetic osteolysis leading to asceptic loosening remains the primary cause of failure of joint replacement. Although many inflammatory cell types have been implicated, the exact pathomechanisms of asceptic loosening have not been delineated. In the present study we have adopted a proteomic approach to elucidate the initial signals that are expressed to particulate material, using an in vitro cell culture system. Human lung fibroblasts MRC-5 were cultured with Cobalt Chromium (CoCr ASTM F-75, 1,7,µm) particles. Cells were harvested after 72,h incubation and total cellular proteins extracted for downstream analysis via 2D Gel Electrophoresis and tandem mass spectrometry using MALDI-TOF-TOF-MS. Thirteen protein spots showed greater than twofold increase, following 72,h incubation of fibroblast with CoCr particles. Four of these proteins were identified by tandem mass spectrometry. These were Annexin II, Pyruvate kinase, Triose phosphate isomerase, and N-myc downstream regulated gene 1 protein. Cobalt is a hypoxia mimicking agent and N-myc downstream regulated gene 1 protein, Triose phosphate isomerase, Pyruvate kinase, and Annexin II are important hypoxia regulated gene products that are found to be over expressed in cellular oxidative stress response. Our data indicates that exposure of fibroblast to CoCr alloy induces the transition of these cells into a hypoxia like state and oxidative stress even in normoxic culture conditions. The study reflects the possibility of the presence of a hypoxic environment in the periprosthetic tissue surrounding metallic implants. Published by Wiley Periodicals, Inc. J Orthop Res 28:1360,1367, 2010 [source] Ethanol-Induced Up-Regulation of the Urokinase Receptor In Cultured Human Endothelial CellsALCOHOLISM, Issue 2 2001Edlue M. Tabengwa Background: Moderate alcohol consumption has been correlated to reduced coronary artery disease (CAD) risk and mortality. This alcohol effect may be mediated in part by an increased endothelial cell (EC) fibrinolysis. ECs synthesize fibrinolytic proteins, tissue plasminogen activator (t-PA), urokinase type plasminogen activator (u-PA), and plasminogen activator inhibitor type-1(PAI-1). In addition, they synthesize and regulate receptors for fibrinolytic proteins, namely (t-PA and plasminogen receptor) Annexin II and u-PA receptor (u-PAR). These receptors play an important role in the regulated expression of receptor-bound plasminogen activator conversion of receptor-bound plasminogen to receptor-bound plasmin on the EC surface (surface-localized fibrinolytic activity). Therefore, systemic factors, such as ethanol, that affect the level, or activity or interaction of one or more of these components, resulting in the increased expression of surface-localized EC fibrinolytic activity, will be expected to reduce the risk for thrombosis, CAD, and myocardial infarction (MI). We have previously shown that low ethanol up-regulates t-PA and u-PA gene transcription, while it down-regulates PAI-1, hence resulting in increased (sustained, 24 hr) surface-localized EC fibrinolytic activity. The current studies were carried out to determine whether low ethanol increased u-PAR expression in cultured human umbilical cord vein ECs (HUVECs). Methods: Cultured HUVECs were preincubated (1 hr) in the absence/presence of ethanol (0.025,0.2%, v/v); u-PAR mRNA (RT-PCR), antigen (western blot), and activity (125I-u-PA ligand binding/Scatchard analysis) levels were then measured after 0,24 hr. To determine whether the ethanol-induced changes in the u-PAR expression were transcriptional, transient transfection studies were carried out using a u-PAR/luciferase promoter construct (pu-PAR120/luc [1.2-kb u-PAR promoter fragment ligated to a promoterless luciferase vector]). Results: uPAR mRNA levels increased 2- to 3-fold and antigen levels (western blot) increased 2- to 4-fold while u-PA binding activity increased 36% (1.25 vs. 1.7 , 105 sites/cell, Bmax) without significantly affecting the Kd (1,2 nM). Transient transfection of cultured HUVECs with a pu-PAR120/luc construct resulted in a 2- to 3-fold increase in promoter activity in ethanol-induced cultures, compared with controls. Conclusion: These combined results demonstrate that low ethanol (,0.1%, v/v) induces the up-regulation of u-PAR gene transcription, resulting in increased u-PAR ligand binding activity. These results also further identify/define the contribution and role of another fibrinolytic protein in the overall ethanol-induced increase in surface-localized EC fibrinolysis that may underlie and contribute, in part, to the cardioprotection attributed to moderate alcohol consumption. [source] Ethanol-Induced Up-Regulation of Candidate Plasminogen Receptor Annexin II in Cultured Human Endothelial CellsALCOHOLISM, Issue 6 2000Edlue M. Tabengwa Introduction Epidemiological studies indicate that moderate alcohol consumption reduces the risk for coronary heart disease and that this cardioprotective benefit may be mediated, in part, by increased fibrinolysis. Endothelial cells (ECs) synthesize plasminogen activators, tissue-type plasminogen activator (t-PA), urokinase-type plasminogen activator (u-PA), receptors for plasminogen activators, and a receptor for plasminogen, annexin II (Ann-II). These receptors localize and facilitate receptor-bound plasminogen activator-mediated conversion of receptor-bound plasminogen to receptor-bound plasmin on the EC surface, which results in the regulated expression of surface-localized EC fibrinolytic activity. Ethanol is a systemic factor that affects these components, which increases EC fibrinolysis and hence reduces the risk for thrombosis, coronary heart disease, and myocardial infarction (MI). Methods: This study was carried out to determine whether low ethanol (0.1% v/v) increased plasminogen receptor, Ann-II antigen (western blot), messenger ribonucleic acid (mRNA) (reverse transcription polymerase chain reaction; RT-PCR) expression, activity (ligand binding/Scatchard analysis), and hence fibrinolysis (plasmin generation) in cultured human ECs. Results: Plasminogen receptor activity increased ,2-fold (2.5 vs. 5.6 × 106 sites/cell), as evidenced by increased 125I-labeled Glu-plasminogen ligand binding/Scatchard analysis. In addition, western blot analyses indicated an increase in Ann-II antigen, and mRNA levels increased ,2-fold (RT-PCR). This increase in Ann-II expression was concomitant with ,2- to 3-fold sustained increase (,24 hr) in surface-localized EC fibrinolytic activity. Nuclear transcription run-on assays showed an ,5- to 6-fold increase in new 32P-labeled Ann-II mRNA levels, compared with controls (no ethanol). Conclusions: These results demonstrated that low ethanol increased Ann-II antigen/mRNA levels and up-regulated Ann-II gene expression at the transcriptional level. The results further identify and define the contribution and role of the plasminogen receptor, Ann-II, in the ethanol-induced mechanism of increased EC fibrinolysis that may underlie and contribute, in part, to the cardioprotective benefit associated with moderate alcohol consumption. [source] Expression of a releasable form of annexin II by human keratinocytesJOURNAL OF CELLULAR BIOCHEMISTRY, Issue 4 2002Feridoun Karimi-Busheri Abstract Annexin II is a multifunctional calcium-dependent phospholipid binding protein whose presence in epidermis has previously been reported. However, like other members of annexin family, annexin II has been regarded as either an intracellular protein or associated with the cellular membrane. Here, we report the presence of a releasable annexin II and p11, two monomers of annexin II tetramer, in keratinocyte-conditioned medium (KCM). Proteins present in KCM were fractionated on a gel filtration column and following further evaluation, a releasable protein with apparent MW of 36 kDa was identified. Further characterization identified this protein as the p36 monomer of annexin II tetramer. The phospho-tyrosine antibody did not visualize this protein as the phosphorylated form of p36. Several experiments were conducted to examine whether this protein is soluble or associated with keratinocyte cell membranes in the conditioned medium. A centrifugation of conditioned medium was not able to bring this protein down into the pellet. Surprisingly, the results of Western analysis identified p36 and p11, two monomers of the annexin II tetramer, in conditioned medium derived from either keratinocytes cultured alone or keratinocytes co-cultured with fibroblasts. In contrast to the keratinocyte-conditioned medium in which annexin II was easily detectable, both monomers were barely detectable in conditioned medium collected from dermal fibroblasts. This finding was in contrast to the cell lysates in which p36 was detectable in both keratinocytes and fibroblasts. However, the amount of this protein was markedly higher in keratinocyte lysate relative to that of dermal fibroblasts. Conditioned medium derived from keratinocyte established from adult showed a higher level of annexin II compared to that of keratinocytes established from newborn babies. The expression of p11 seems to increase with differentiation of keratinocytes derived from either adult or newborn skin samples. When the site of annexin synthesis in human skin was examined by immunohistochemical staining, the antibody for p36 localized the annexin to the keratinocyte cell members in the basal and suprabasal keratinocytes. In conclusion, Western blot detection of both p36 and p11 in conditioned medium from skin cells revealed that human keratinocytes, but not fibroblasts, express a releasable monomer form of annexin II which is regulated by differentiation status of keratinocytes. This finding is consistent with the localization of annexin II detected by immunohistochemical staining. J. Cell. Biochem. 86: 737,747, 2002. © 2002 Wiley-Liss, Inc. [source] Ethanol-Induced Up-Regulation of Candidate Plasminogen Receptor Annexin II in Cultured Human Endothelial CellsALCOHOLISM, Issue 6 2000Edlue M. Tabengwa Introduction Epidemiological studies indicate that moderate alcohol consumption reduces the risk for coronary heart disease and that this cardioprotective benefit may be mediated, in part, by increased fibrinolysis. Endothelial cells (ECs) synthesize plasminogen activators, tissue-type plasminogen activator (t-PA), urokinase-type plasminogen activator (u-PA), receptors for plasminogen activators, and a receptor for plasminogen, annexin II (Ann-II). These receptors localize and facilitate receptor-bound plasminogen activator-mediated conversion of receptor-bound plasminogen to receptor-bound plasmin on the EC surface, which results in the regulated expression of surface-localized EC fibrinolytic activity. Ethanol is a systemic factor that affects these components, which increases EC fibrinolysis and hence reduces the risk for thrombosis, coronary heart disease, and myocardial infarction (MI). Methods: This study was carried out to determine whether low ethanol (0.1% v/v) increased plasminogen receptor, Ann-II antigen (western blot), messenger ribonucleic acid (mRNA) (reverse transcription polymerase chain reaction; RT-PCR) expression, activity (ligand binding/Scatchard analysis), and hence fibrinolysis (plasmin generation) in cultured human ECs. Results: Plasminogen receptor activity increased ,2-fold (2.5 vs. 5.6 × 106 sites/cell), as evidenced by increased 125I-labeled Glu-plasminogen ligand binding/Scatchard analysis. In addition, western blot analyses indicated an increase in Ann-II antigen, and mRNA levels increased ,2-fold (RT-PCR). This increase in Ann-II expression was concomitant with ,2- to 3-fold sustained increase (,24 hr) in surface-localized EC fibrinolytic activity. Nuclear transcription run-on assays showed an ,5- to 6-fold increase in new 32P-labeled Ann-II mRNA levels, compared with controls (no ethanol). Conclusions: These results demonstrated that low ethanol increased Ann-II antigen/mRNA levels and up-regulated Ann-II gene expression at the transcriptional level. The results further identify and define the contribution and role of the plasminogen receptor, Ann-II, in the ethanol-induced mechanism of increased EC fibrinolysis that may underlie and contribute, in part, to the cardioprotective benefit associated with moderate alcohol consumption. [source] Functional Differences Between Growth Plate Apoptotic Bodies and Matrix Vesicles,JOURNAL OF BONE AND MINERAL RESEARCH, Issue 10 2003Thorsten Kirsch Abstract Mineralization often occurs in areas of apoptotic changes. Our findings indicate that physiological mineralization is mediated by matrix vesicles. These matrix vesicles use mechanisms to induce mineralization that are different from the mechanisms used by apoptotic bodies released from apoptotic cells. Therefore, different therapeutic approaches must be chosen to inhibit pathological mineralization depending on the mechanism of mineralization (matrix vesicles versus apoptotic bodies). Introduction: Physiological mineralization in growth plate cartilage is restricted to regions of terminally differentiated and apoptotic chondrocytes. Pathological mineralization of tissues also often occurs in areas of apoptosis. We addressed the question of whether apoptotic changes control mineralization events or whether both events are regulated independently. Methods: To induce mineralization, we treated growth plate chondrocytes with retinoic acid (RA); apoptosis in these cells was induced by treatment with staurosporine, anti-Fas, or TNF,. The degrees of mineralization and apoptosis were determined, and the structure and function of matrix vesicles and apoptotic bodies were compared. Results: Release of matrix vesicles and mineralization in vivo in the growth plate occurs earlier than do apoptotic changes. To determine the functional relationship between apoptotic bodies and matrix vesicles, growth plate chondrocytes were treated with RA to induce matrix vesicle release and with staurosporine to induce release of apoptotic bodies. After 3 days, approximately 90% of staurosporine-treated chondrocytes were apoptotic, whereas only 2,4 % of RA-treated cells showed apoptotic changes. RA- and staurosporine-treated chondrocyte cultures were mineralized after 3 days. Matrix vesicles isolated from RA-treated cultures and apoptotic bodies isolated from staurosporine-treated cultures were associated with calcium and phosphate. However, matrix vesicles were bigger than apoptotic bodies. Furthermore, matrix vesicles but not apoptotic bodies contained alkaline phosphatase and Ca2+ channel-forming annexins II, V, and VI. Consequently, matrix vesicles but not apoptotic bodies were able to take up Ca2+ and form the first mineral phase inside their lumen. Mineralization of RA-treated cultures was inhibited by antibodies specific for annexin V but not mineralization of staurosporine-treated cultures. Conclusion: Physiological mineralization of growth plate chondrocytes is initiated by specialized matrix vesicles and requires alkaline phosphatase and annexins. In contrast, mineral formation mediated by apoptotic bodies occurs by a default mechanism and does not require alkaline phosphatase and annexins. [source] | |||||||||||||