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Biomedical subjects

E Kaczmarek

Publications and source records attributed to E Kaczmarek.

At least 19 recordsLinked to original sources
PubMed2003

Heavy chain ferritin acts as an antiapoptotic gene that protects livers from ischemia reperfusion injury.

Heme oxygenase-1 (HO-1) is induced under a variety of pro-oxidant conditions such as those associated with ischemia-reperfusion injury (IRI) of transplanted organs. HO-1 cleaves the heme porphyrin ring releasing Fe2+, which induces the expression of the Fe2+ sequestering protein ferritin. By limiting the ability of Fe2+ to participate in the generation of free radicals through the Fenton reaction, ferritin acts as an anti-oxidant. We have previously shown that HO-1 protects transplanted organs from IRI. We have linked this protective effect with the anti-apoptotic action of HO-1. Whether the iron-binding properties of ferritin contributed to the protective effect of HO-1 was not clear. We now report that recombinant adenovirus mediated overexpression of the ferritin heavy chain (H-ferritin) gene protects rat livers from IRI and prevents hepatocellular damage upon transplantation into syngeneic recipients. The protective effect of H-ferritin is associated with the inhibition of endothelial cell and hepatocyte apoptosis in vivo. H-ferritin protects cultured endothelial cells from apoptosis induced by a variety of stimuli. These findings unveil the anti-apoptotic function of H-ferritin and suggest that H-ferritin can be used in a therapeutic manner to prevent liver IRI and thus maximize the organ donor pool used for transplantation.

Adenoviridae↗
PubMed2002

Stages of the rat thymic medulla development in foetal period.

Development of thymic medulla was examined on consecutive gestational days (GD) in Wistar rats. Medullary thymic epithelial cells (TEC) were identified by immunocytochemical localisation of neuron-specific enolase (NSE). Organisation of thymic medullary architecture was determined by interaction of thymocytes with NSE-positive TEC, that led to formation of lymphoepithelial complexes (GD 19), in which the cells exhibited proliferative activity or traits of apoptosis. The studies indicated that differentiation events and organisation of thymic medulla require stage-specific interactions between TEC and thymocytes.

Animals↗
PubMed2001

Identification and validation of P311 as a glioblastoma invasion gene using laser capture microdissection.

The mRNA expression profiles from glioblastoma cells residing at the tumor core and invasive rim of a human tumor resection were compared. From a single tumor specimen, 20,000 single cells from each region were collected by laser capture microdissection. Differential expression of 50-60 cDNA bands was detected. One of the sequences overexpressed by the invasive cells showed 99% homology to the P311 gene, the protein product of which is reported to localize at focal adhesions. Relative overexpression of P311 by invading glioblastoma cells compared with tumor core was confirmed by quantitative reverse transcription-PCR of six glioblastoma specimens after laser capture microdissection collection of rim and core cells. In vitro studies using antisense oligodeoxynucleotides and integrin activation confirmed the role of P311 in supporting migration of malignant glioma cells. Immunochemistry studies confirmed the presence of the P311 protein in tumor cells, particularly at the invasive edge of human glioblastoma specimens.

Amino Acid Sequence↗
PubMed2001

RAFTK/Pyk2 involvement in platelet activation is mediated by phosphoinositide 3-kinase.

Platelet activation by different agonists initiates a signalling cascade involving the phosphorylation of several protein kinases, which control key regulatory events. Previously, we demonstrated that the related adhesion focal tyrosine kinase (RAFTK, Pyk2) was involved in an early phase of platelet activation, independent of integrin and glycoprotein IIb-IIIa activation. In this study, we demonstrate that RAFTK is co-immunoprecipitated with phosphoinositide 3-kinase (PI3K) upon platelet activation, and that thrombin, ADP and collagen induced the phosphorylation of both PI3K and RAFTK. A low dose of thrombin (0.015 U/ml) induced RAFTK phosphorylation and platelet aggregation in a PI3K activity-dependent manner, whereas a high dose of thrombin (0.1 U/ml) induced these events in a PI3K activity-independent manner. ADP and collagen also induced RAFTK phosphorylation and platelet aggregation in a PI3K activity-dependent manner, similar to that of the low-dose thrombin. Furthermore, protein tyrosine phosphatase activity was associated with RAFTK in response to platelet activation, and was found to be that of protein tyrosine phosphatase-2 (SHP-2). The association of SHP-2 with RAFTK was PI3K-dependent and was increased upon RAFTK phosphorylation. Taken together, our results strongly suggest that the involvement of RAFTK in platelet activation is mediated via the PI3K pathway.

Adenosine Diphosphate↗
PubMed2001

Kinetics of thymic stroma development in the foetal period.

The kinetics of thymic epithelial cell development was examined in Wistar strain rats between 13th and 21st days of foetal life. The studies were based on immunocytochemical localisation of cytokeratin 16 (CK 16), Ki67 and on ultrastructural observations of thymus development. Expression of CK16 in individual groups was evaluated using the Micro Image v.4.0 software. In order to monitor changes in CK16 expression in individual days of foetal life, their results were subjected to statistical analysis, demonstrating: (1) correlation between CK16 expression and duration of foetal life, (2) most pronounced CK16 expression on the 16th day of foetal life, (3) typical localisation of CK16-positive cells in individual days of foetal life. The morphological observations suggest that individual subpopulations of epithelial cells differ in their kinetics of proliferative activity.

Animals↗
PubMed2001

Death-associated protein 3 (Dap-3) is overexpressed in invasive glioblastoma cells in vivo and in glioma cell lines with induced motility phenotype in vitro.

PURPOSE: To discover the genetic determinants of glioma invasion in vivo, we compared the mRNA expression profiles of glioblastoma cells residing at the tumor core versus those at the invasive rim of a human tumor resection. EXPERIMENTAL DESIGN: From a single glioblastoma specimen, 20,000 individual cells from each region (core and invasive rim) were collected by laser capture microdissection and analyzed by mRNA differential display. Differential expression of gene candidates was confirmed by laser capture microdissection and quantitative reverse transcription-PCR in additional glioblastoma multiforme specimens, and the role in migration was further evaluated in glioma cell lines in vitro. RESULTS: Reproducible overexpression the death-associated Protein 3 (Dap-3) mRNA (NM 004632, GenBank; also reported as human ionizing resistance conferring protein mRNA, HSU18321, GenBank) by invasive cells was identified. Although the full-length Dap-3 protein has been described as proapoptotic, the NH(2)-terminal fragment can act in a dominant negative way resulting in protection from programmed cell death. In glioma cell lines T98G and G112 with an induced motility phenotype, Dap-3 was up-regulated at the mRNA and protein level as assessed by quantitative reverse transcription-PCR, cDNA microarray, and Western blot analysis. These cells showed an increased resistance to undergo camptothecin-induced apoptosis, which was overcome by effective Dap-3-antisense treatment. Antisense treatment also decreased the migration ability of T98G cells. CONCLUSIONS: Dap-3 is up-regulated in invasive glioblastoma multiforme cells in vivo and in glioma cells with an induced motility phenotype in vitro. When migration is activated, Dap-3 is up-regulated and cells become resistant to apoptosis. These findings suggest that Dap-3 confers apoptosis-resistance when migration behavior is engaged.

Apoptosis↗
PubMed2001

The application of electron microscopic morphometry as helpful method in the diagnosis of focal segmental glomerulosclerosis (FSGS) early phase. I. Morphometric electron microscopic studies of renal glomeruli in cases of focal segmental glomerulosclerosis (FSGS), minimal change disease (MCD) and mesangioproliferative glomerulonephritis (GNMES) in children.

Electron microscopy morphometric studies were carried out on material obtained from children with minimal change disease (MCD), mesangioproliferative glomerulonephritis (GNMES) and focal segmental glomerulosclerosis (FSGS). The results indicated that an increase in the volume of the matrix in mesangioproliferative glomerulonephritis was due to an increase in the number of cells. The amount of produced matrix in mesangioproliferative glomerulonephritis was proportional to the number of cells in mesangium (so there is no overproduction of matrix). The ratios of mesangial matrix volume to cell volume and matrix volume to the volume of the entire mesangial region in MCD and GNMES were similar and differed significantly from the ratios found in FSGS. The present findings indicate that morphometric studies may be useful in the early diagnosis of glomerular sclerosis. This is particularly significant in cases where light microscopic examination fails to reveal changes indicative of glomerular sclerosis.

Child, Preschool↗
PubMed2001

The application of electron microscopic morphometry as a helpful method in the diagnosis of focal segmental glomerulosclerosis (FSGS) early phase. II. Clinical usefulness of electron microscopic morphometric studies in cases of minimal change disease (MCD) and mesangioproliferative glomerulonephritis (GNMES) with suspicion of progression into focal segmental glomerulosclerosis (FSGS).

Clinical and morphological analysis (including morphometric studies of electron microscopic material) was made in 15 children with MCD and 15 children with GNMES. In both groups, an early phase of FSGS was suspected on the basis of electron microscopic studies. Moreover, analysis included the results obtained in 13 children with the diagnosis of FSGS and in whom repeated biopsies were performed. In most of them, MCD or GNMES was diagnosed from the first biopsy. In most children in whom electron microscopic studies revealed an increase in matrix area in some mesangial regions, thereby suggesting an early stage of glomerular sclerosis, the results of morphometric studies resembled or were identical to the results obtained from a control group with the established diagnosis of FSGS. These findings indicate that morphometric studies of electron microscopic material are significant. The results, when compared with the clinical data, confirm the usefulness of such a diagnostic procedure.

Child, Preschool↗
PubMed2000

Recombinant adenoviral mediated CD39 gene transfer prolongs cardiac xenograft survival.

BACKGROUND: Extracellular ATP and ADP may be important mediators of vascular inflammation and thrombosis. Nucleoside triphosphate diphosphohydrolase (NTPDase or CD39) is a vascular ectoenzyme that hydrolyses ATP and ADP; however, this activity is lost during reperfusion injury. We show that the supplementation of NTPDase activity within xenograft vasculature using CD39 recombinant adenoviruses (AdCD39) has protective effects in vivo. METHODS: Recombinant adenoviruses containing human CD39 or beta-galactosidase (Adbeta-gal) encoding genes were constructed. Hartley guinea pig coronary arteries were perfused ex vivo with University of Wisconsin solution containing 10(9) plaque-forming units of the recombinant adenovirus. Infected grafts were then implanted in the abdomen of complement depleted Lewis rats. RESULTS: NTPDase activities decreased in all grafts within the first 24 hr and subsequently recovered only in those hearts infected with AdCD39. Immunohistological examination of AdCD39-infected grafts confirmed successful CD39 gene transfer into the endocardium and macrovasculature. Expression of CD39 modestly prolonged graft survival (90.2+/-5.4 hr, mean+/-SD, n=5) when compared with Adbeta-gal-infected grafts (67.4+/-5.4 hr, P<0.005) and perfusion controls (66.4+/-5.2 hr; P<0.005). CONCLUSIONS: Recombinant adenoviral infection can induce expression of CD39 within cardiac xenografts and provide survival benefits in vivo. Our data show that ex vivo infection by recombinant adenovirus vectors can result in vascular expression of a potential therapeutic agent.

Adenosine Triphosphatases↗
PubMed2000

CD39 modulates IL-1 release from activated endothelial cells.

The activation of endothelial cells (EC) and monocyte-macrophages (M&phi;) by lipopolysaccharide (LPS) is considered an important element of the vascular injury observed in endotoxemia. Interleukin-1 (IL-1) beta release from M&phi; in response to LPS, appears to be mediated by the autocrine/paracrine release of ATP via P2X7 receptor activation. In EC, similar nucleotide-mediated signaling pathways may be influenced by high levels of expression of CD39, the vascular nucleoside triphosphate diphosphohydrolase (NTPDase; ENTPD I). To determine whether CD39 modulates ATP-mediated release of IL-1 from EC, we stimulated human EC with LPS and measured levels of ATP secretion and IL-1 release. LPS triggered ATP secretion from EC that was soon followed by IL-1alpha release. Overexpression of CD39 following infection with recombinant CD39 adenoviral vectors (AdCD39) abrogated the initial phase of ATP secretion and inhibited IL-1alpha release; comparable results were obtained with soluble NTPDase. These data demonstrate that CD39/NTPDase modulates IL-1alpha release from LPS stimulated human EC.

Adenosine Triphosphatases↗
PubMed2000

Palmitoylation targets CD39/endothelial ATP diphosphohydrolase to caveolae.

Ectonucleotidases influence purinergic receptor function by the hydrolysis of extracellular nucleotides. CD39 is an integral membrane protein that is a prototype member of the nucleoside 5'-triphosphate diphosphohydrolase family. The native CD39 protein has two intracytoplasmic and two transmembrane domains. There is a large extracellular domain that undergoes extensive glycosylation and can be post-translationally modified by limited proteolysis. We have identified a potential thioester linkage site for S-acylation within the N-terminal region of CD39 and demonstrate that this region undergoes palmitoylation in a constitutive manner. The covalent lipid modification of this region of the protein appears to be important both in plasma membrane association and in targeting CD39 to caveolae. These specialized plasmalemmal domains are enriched in G protein-coupled receptors and appear to integrate cellular activation events. We suggest that palmitoylation could modulate the function of CD39 in regulating cellular signal transduction pathways.

Adenosine Triphosphatases↗
PubMed2000

CD39 modulates endothelial cell activation and apoptosis.

BACKGROUND: CD39 is the dominant vascular nucleoside triphosphate diphosphohydrolase (NTPDase) that exerts major effects on platelet reactivity by the regulated hydrolysis of extracellular adenine nucleotides. The effects of NTPDases on endothelial cell (EC) activation and apoptosis remain unexplored. MATERIAL AND METHODS: Recombinant replication-deficient adenoviruses were constructed with human CD39 cDNA (rAdCD39) or the bacterial beta-galactosidase (rAdbetagal). RESULTS: Intact human umbilical vein EC cultures infected with rAdCD39 had substantial and stable increases in NTPDase biochemical activity (14.50 +/- 3.50 Pi nmole/well/min), when contrasted with noninfected cells (0.95 +/- 0.002) and rAdbetagal infected cells (1.01 +/- 0.02; p<0.005). Increased NTPDase activity efficiently inhibited immediate type 2Y purinergic receptor (P2Y)-mediated EC activation responses viz. von Willebrand factor secretion in response to extracellular ATP. In addition, CD39 up-regulation blocked ATP-induced translocation of the transcription nuclear factor (NF)-kappaB to the cell nucleus, and abrogated transcription of mRNA encoding E-selectin, and consequent protein synthesis. CD39 also decreased the extent of apoptosis triggered by putative type-2X purinergic (P2X7) receptors in response to high concentrations of extracellular ATP in vitro. CONCLUSION: These properties of CD39 indicate primary vascular protective effects with potential therapeutic applications.

Adenosine Triphosphatases↗
PubMed1999

Suppression of ATP diphosphohydrolase/CD39 in human vascular endothelial cells.

Vascular ATP diphosphohydrolase/CD39 is an endothelial cell membrane protein with both ecto-ATPase and ecto-ADPase activities. Suppression of constitutive CD39 expression may result in elevated concentrations of ATP and ADP at the vascular interface that could predispose to thrombosis and inflammation. To study the effects of suppression of CD39 synthesis, stable 25-base antisense chimeric oligonucleotides targeting sequences at the 5' region of CD39 were designed. Transfection of these stable oligomers into cultured human endothelial cells resulted in dramatic decreases in levels of CD39 mRNA transcripts. Following transfection with antisense oligonucleotides, total ADPase activity fell from 26.0 +/- 3.1 in control cultures to 9.5 +/- 3.4 nmol of P(i) min(-1) (mg of protein)(-1) (p < 0.005); suppression of CD39 protein expression was also observed by Western blotting. Decreases in ATP diphosphohydrolase activity were associated with increases in concentrations of extracellular purine nucleotides released following stimulation of endothelial cells. Rates of initial hydrolysis of extracellular ATP released from purinergic agonist-stimulated endothelial cells decreased from 17.9 +/- 5.0 to 4.8 +/- 0.5 pmol min(-1) per 10(6) cells (p < 0.005) in antisense transfected cells. Therefore, CD39 regulates extracellular ATP concentrations and may be an important modulator of purinergic receptor activity in vascular endothelial cells.

Adenosine Diphosphate↗
PubMed1999

CD39 as a caveolar-associated ectonucleotidase.

CD39 is a human lymphoid cell activation antigen, (also referred to E-ATPDase or apyrase) that hydrolyzes extracellular ATP and ADP. Although it has been widely studied, its physiological role, however, still remains unclear. This ectonucleotidase generally is said to be evenly distributed in the membrane of the cells. However, we observed that in cell types which possess caveolae, specialised membrane invaginations involved in signalling, CD39 is preferentially targeted to these membrane microdomains. Since all molecules involved in signalling (eNOS, G-proteins, receptors) which are targeted to the caveolae undergo posttranslational modifications (e.g., palmitoylation) we hypothesize the same to be the case for CD39. Furthermore, its presence in the caveolae supports its participation in signalling events.

Adenosine Triphosphatases↗
PubMed1999

Structural elements and limited proteolysis of CD39 influence ATP diphosphohydrolase activity.

CD39, the mammalian ATP diphosphohydrolase (ATPDase), is thought to contain two transmembrane domains and five "apyrase conserved regions" (ACR) within a large extracellular region. To study the structure of this ectoenzyme, human CD39 was modified by directed mutations within these ACRs or by sequential deletions at both termini. ATPDase activity was well preserved with FLAG tagging, followed by the removal of either of the demonstrated C- or N-transmembrane regions. However, deletions within ACR-1 (aa 54-61) or -4 (aa 212-220), as well as truncation mutants that included ACR-1, -4, or -5 (aa 447-454), resulted in substantive loss of biochemical activity. Intact ACR-1, -4, and -5 within CD39 are therefore required for maintenance of biochemical activity. Native and mutant forms of CD39 lacking TMR were observed to undergo multimerization, associated with the formation of intermolecular disulfide bonds. Limited tryptic cleavage of intact CD39 resulted in two noncovalently membrane-associated fragments (56 and 27 kDa) that substantially augmented ATPDase activity. Glycosylation variation accounted for minor heterogeneity in native and mutant forms of CD39 but did not influence ATPDase function. Enzymatic activity of ATPDase may be influenced by certain posttranslational modifications that are relevant to vascular inflammation.

Adenosine Triphosphatases↗
PubMed1999

Visualisation and modelling of renal capillaries from confocal images.

A computer aided design was developed to support three-dimensional visualisation and modelling of vascular networks. Volume data comprised a series of images obtained using a Zeiss confocal laser scanning microscope. The profiles of vessels were automatically segmented using two-dimensional morphological filters. Segmented contours of the vessels were used to form a spatial model of the network. The centre points of segmented contours were used to derive a three-dimensional graph representing the vascular network. The proposed method was applied to renal capillary networks of normal rats, and showed well the lobular structure of glomeruli. The average length of renal capillary networks was 6.09 mm. Three-dimensional models based on confocal data require much less effort than reconstructions based on serial sections, and can be adapted for any vascular patterns.

Animals↗
PubMed1999

Analysis of CD39/ATP diphosphohydrolase (ATPDase) expression in endothelial cells, platelets and leukocytes.

Purinergic signaling may influence hemostasis, inflammatory responses and apoptosis. Therefore, hydrolysis of extracellular ATP and ADP by the ATP diphosphohydrolase (ATPDase) could regulate these processes. We have previously demonstrated the identity between the vascular ATPDase and CD39. Here we show that levels of CD39 expression correlate with ATPDase activity in human endothelial cells (EC), platelets and selected monocyte, NK, and megakaryocyte cell lines. Western blotting revealed one to three isoforms of CD39/ATPDase: mobility variations of major protein resulted from post-translational modifications. Northern blotting and primer extension indicated two major mRNA transcripts and one transcription start point, respectively. In addition, mRNAs specific for purinergic P2 receptors were detected in all of the investigated cells, suggesting that the coexpressed CD39/ATPDase may regulate purinergic signaling. Thrombotic and inflammatory responses may be modulated by the expression of CD39/ATPDase.

Adenosine Diphosphate↗