| Volume 7 (2002) pp 961-969 |
| Title |
ELECTRIC INTERACTIONS AT THE LIPID MEMBRANE SURFACE |
| Authors |
Marian Podolak* and Dariusz Man |
| Abstract |
This work presents the results of an experimental study and of
computer simulations concerning electric interactions in the surface layer of egg
yolk lecithin (EYL) liposome membranes. The surface layer is formed by EYL
polar heads, which possess features of electric dipoles, and positive charged
polar heads belonging to admixtures of quaternary ammonium salts (AS). The
results of the experimental study are in good agreement with the ones of the
computer simulations. It was found that fluidity of the membranes, at a given
concentration of AS, obtains the extremal (minimal) value. Similarly, the
binding energy of the dipoles-positive charges system behaves like that in
computer simulations. Moreover, the locations of the fluidity extremum and
those of the binding energy depend on the charge of the AS polar heads as well
as on the degree of electric interactions screening by the environment. At a
certain optimal value of the screening coefficient, the energy of the system is the
lowest (the most negative) and together with the rise in AS charge, the minimum
of the energy moves towards its higher concentrations. |
| Address and Contact Information |
Institute of Physics, Opole University, Oleska 48, 45-052 Opole, Poland
* Corresponding author, E-mail: podolak@uni.opole.pl |
 ![[Rozmiar: 1332 bajtĂłw]](pic/abstract.gif) |
| Volume 7 (2002) pp 971-982 |
| Title |
COMPUTER SIMULATION STUDIES ON THE SIGNIFICANCE OF
LIPID POLAR HEAD CHARGE |
| Authors |
Krystian Kubica* |
| Abstract |
Ripple phase modelling was achievable by taking into consideration
the dipole structure of the polar heads of model membrane molecules. Computer
simulations enabled the selective analysis of a model membrane. Considering
only the hydrophobic part of the lipid membrane, the gel-fluid transition stage
can be obtained in such a simulation. Assuming an additional degree of freedom,
the entire molecule can move along the normal to the membrane surface
projected from two C-C bonds. The amounts of shifted lipids were 17% and
33% at temperatures of 300 K (gel) and 330 K (fluid), respectively. Taking into
account only polar head interactions in media of different ionic strength I,
dielectric constant e, and an effective charge and temperature, we could observe
the same behaviour of the examined system independently of the values of I and
e when the charge was reduced to q/2. The amount of shifted heads at 300 K
decreases sharply with the reduced charge value, with an accompanying increase
in the number of 'standing' polar heads. Summing up, it can be stated that
hydrocarbon lipid chains exhibit a greater tendency to displacement in the fluid
state than in the gel state. However, the polar heads behave in the opposite way:
there are more displaced heads at 300 K than at 330 K. Thus, the overall analysis
of the interactions between the molecules of the model membrane should enable
us to find model parameters suitable for studying the lipid membrane at a wide
range of temperatures. Finally, an electrostatic profile close to the membrane
surface could be estimated in different membrane states. This should be useful in
membrane-biologically active compound interaction analysis. |
| Address and Contact Information |
Department of Physics and Biophysics, Agricultural University, Norwida 25,
50-375 Wrocław, Poland
* E-mail:KUBICA@OZI.AR.WROC.PL |
|
| Volume 7 (2002) pp 983 - 993 |
| Title |
MECHANISTIC APPROACH TO MEMBRANE MASS TRANSPORT
PROCESSES (MINI REVIEW) |
| Authors |
Marian Kargol |
| Abstract |
Since the physical interpretation of practical Kedem-Katchalsky
equations is not clear, we consider an alternative, mechanistic approach to
membrane transport generated by osmotic and hydraulic pressure. We study a
porous membrane with randomly distributed pore sizes (radii). We postulate that
the reflection coefficient (sp) of a single pore may equal 1 or 0 only. From this
postulate we derive new (mechanistic) transport equations. Their advantage is in
clear physical interpretation. |
| Address and Contact Information |
Institute of Physics, Świętokrzyska Academy, 25-406 Kielce, Poland |
|
| Volume 7 (2002) pp 995-1018 |
| Title |
ALTERATIONS IN CELL NUCLEI DURING APOPTOSIS |
| Authors |
Małgorzata Rogalińska |
| Abstract |
Apoptosis is a genetically programmed phenomenon that aids in
maintaining homeostasis in multicellular organisms. The characteristic
morphological features of apoptosis are highly conservative and are dependent
on the cell type and the apoptotic inducer. The nuclear events occurring during
apoptosis include changes at the molecular level (i.e. DNA cleavage,
modifications of nuclear polypeptides, and proteolysis of several proteins
important for cell maintenance), and, consequently, alterations at the
morphological level (i.e. chromatin condensation, nuclear shrinkage, DNA
fragmentation and apoptotic body formation). These events are still not fully
understood. It is very probable that a progressive decrease in pH could also be an
essential factor for the induction of nuclease and protease activities, and an
important element of the optimal conditions for their function. This review
details the current state of knowledge on apoptotic nuclear events, with
particular focus on the proteins involved in the execution of apoptosis in cell
nuclei, and on the differences in substrate cleavage profiles for different types of
cell undergoing cell death. |
| Address and Contact Information |
University of Łódź, Department of Cytobiochemistry, Banacha 12/16,
90-237 Łódź, Poland
|
|
| Volume 7 (2002) pp 1019-1035 |
| Title |
THE NUCLEAR LAMINS AND THE NUCLEAR ENVELOPE |
| Authors |
Ryszard Rzepecki |
| Abstract |
The cell nucleus is separated from the rest of the cell by the nuclear
envelope. The nuclear envelope, nuclear envelope proteins and nuclear lamina
organise the structure of the entire nucleus and the chromatin via a myriad of
interactions. These interactions are dynamic, change with the change (progress)
of the cell cycle, with cell differentiation and with changes in cell physiology. |
| Address and Contact Information |
Institute of Biochemistry and Molecular Biology, University of Wrocław,
Przybyszewskiego 63/77, 51-148 Wrocław, Poland |
|
| Volume 7 (2002) pp 1037-1045 |
| Title |
THE ISOFORM- AND LOCATION-DEPENDENCE OF THE
FUNCTIONING OF THE PLASMA MEMBRANE CALCIUM PUMP |
| Authors |
Ludmiła Żylińska, Iwona Kawecka, Lilla Lachowicz and Janusz Szemraj |
| Abstract |
The plasma membrane is a specialised multi-component structure
with inter- and intracellular signalling functions. Ca2+ plays a crucial role in
cellular physiology, and an ATP-driven plasma membrane calcium pump
(PMCA) plays the greatest role in the maintenance of a low free Ca2+
concentration in the cytoplasm. The enzyme is coded by four separate genes
(PMCA 1-4), and, due to alternative splicing, more than 20 variants can exist.
PMCA 1 and 4 isoforms are present in almost all tissues, whereas PMCA 2 and
3 are found in more specialised cell types. The variants differ primarily in their
regulatory regions, thus the modulation of calcium pump activity strongly
depends on the isoform and the membrane composition. The unique function of
PMCA isoforms was confirmed using the practical experimental models-a rat
pheochromocytoma cell line, a human neuroblastoma cell line, or, more
recently, knockout mice. In addition, based on the finding that PMCA could
interact with several specific signaling proteins, it was concluded that its
location in defined sites of the cell membrane could be a prerequisite for
efficient intercellular communication. |
| Address and Contact Information |
Neurochemical Laboratory, Department of Biochemistry, Medical University,
Mazowiecka 6/8, 92-215 Łódź, Poland
* Corresponding author, E-mail: luska@csk.am.lodz.pl |
|
| Volume 7 (2002) pp 1047-1057 |
| Title |
THE ROLE OF FOCAL ADHESION KINASE IN THE EMIGRATION
OF CELLS FROM CONFLUENT CULTURES |
| Authors |
Halina Trembacz1, Joanna Miłoszewska1, Bożena Szaniawska1, Maciej Małecki1*, Małgorzata Przybyszewska1, Tomasz Skorski2 and Przemysław Janik1** |
| Abstract |
We studied the effect of the modification of focal adhesion kinase
(FAK) on the growth, migration and adhesion of C3H 10T1/2 cells. Cells
transfected with plasmid coding for antisense FAK displayed a low level of FAK
protein. Interestingly, the transfected cells achieved a higher saturation density at
confluence, and displayed reduced adhesion and enhanced emigration from a
confluent layer of cells when stimulated with fibronectin. In conclusion, it can
be postulated that FAK plays an important role in the mechanism of contact
inhibition. |
| Address and Contact Information |
1Department of Cell Biology, Cancer Center, M. Skłodowska-Curie Institute of
Oncology, W.K. Roentgen 5, 02-781 Warsaw, Poland,
2Center for
Biotechnology, Temple University, 1900 N 12th Street, Philadelphia, USA
*Scholar of the Foundation For Polish Science 2002
** Corresponding author, E-mail: pjanik@coi.waw.pl |
|
| Volume 7 (2002) pp 1059-1064 |
| Title |
EFFECT OF INTRAMUSCULAR APPLICATION OF SELECTED
NEUROPEPTIDES ON MORPHOLOGY OF MUSCLE |
| Authors |
Hanna Gendek-Kubiak |
| Abstract |
The aim of the study was to examine a morphological picture of
guinea pig skeletal muscles injected with neuropeptide Y (NPY), substance P
(SP) or vasoactive intestinal peptide (VIP), to evaluate the influence of a single
injection of the mentioned neuropeptides (NPS) on muscle morphology and mast
cell, T lymphocyte and macrophage chemotaxis. There were different degrees of
muscle fibre injuries as well as different intensities and compositions of
infiltrations inside the muscle after the introduction of the NPS. The observed
changes did not disappear, but increased after 24 hours, comparing to the 3-hour
post-injection changes, suggesting that NPS are proinflammatory rather than
antiinflammatory factors in skeletal muscles. The local, particularly delayed
action of NPS in vivo requires further studies. |
| Address and Contact Information |
Department of Cytophysiology, Histology and Embryology, Medical University
of Łódź, ul. Narutowicza 60, 90-136 Łódź, Poland
E-mail: h_kubiak@hotmail.com |
|
| Volume 7 (2002) pp 1065 - 1071 |
| Title |
REACTIVE OXYGEN SPECIES UPREGULATE EXPRESSION OF
PAI-1 IN ENDOTHELIAL CELLS |
| Authors |
Maria Świątkowska1*, Janusz Szemraj2, Halid N.I. Al-Nedawi3 and Zofia Pawłowska1 |
| Abstract |
Second messengers involved in the signal transduction pathway
leading to induction of the plasminogen activator inhibitor (PAI-1) have not yet
been well characterized. This study focuses on the mechanisms of regulation of
PAI-1 expression by reactive oxygen species (ROS) in human endothelial cells.
Inhibition of the tumor necrosis factor a (TNFa)-induced expression of PAI-1
by antioxidant N-acetyl-L-cysteine (NAC) indicated redox-sensitive
mechanisms involved in the signalling pathway. Because TNFa induces PAI-1
production in endothelial cells, and NAC attenuated this response, we attempted
to investigate the possible involvement of ROS in the activation of PAI-1 by
TNFa. Upregulation of PAI-1 expression in endothelial cells by the stimulation
with TNFa (50ng/ml) or H2O2 (10-200mM), observed by measurement of the
antigen and mRNA levels, was reversed in the presence of NAC (20mM). The
stimulatory effect of ROS was detected also at the level of the PAI-1 promoter in
endothelial cells transfected with plasmid p800 LUC containing a PAI-1
promoter fragment (+71 to -800). The PAI-1 promoter activity was increased in
the presence of ROS, and was suppressed by up to 75% in the presence of
antioxidants [1]. On the basis of this study we can conclude that reactive oxygen
species play an important role in a cytokine-induced activation of PAI-1
expression, and may act as a signal transduction messenger. |
| Address and Contact Information |
1Department of Molecular and Medical Biophysics, 2Department of
Biochemistry, Medical University of Łódź,
3Department of Biogenic Amines,
PAS, Łódź, Poland
* Corresponding author, E-mail: swiatm@zdn.am.lodz.pl |
|
| Volume 7 (2002) pp 1073-1080 |
| Title |
DYNAMIN: CHARACTERISTICS, MECHANISM OF ACTION AND
FUNCTION |
| Authors |
Jolanta Wiejak and Elżbieta Wyroba |
| Abstract |
Dynamin - a member of the GTP-ase protein family - is essential for
many intracellular membrane trafficking events in multiple endocytic processes.
The unique biochemical features of dynamin - especially its propensity to
assemble - enable severing the nascent vesicles from the membrane.
The mechanism of dynamin's action is still a subject of debate - whether it
functions as a mechanochemical enzyme or a regulatory GTPase. The GTPase
domain of dynamin contains three GTP-binding motifs. This domain is very
conservative across the species, including that recently cloned by us in the
unicellular eukaryote Paramecium. Dynamin interacts with a number of partners
such as endophilin and proteins involved in coordination of endocytosis with
motor molecules. A growing body of evidence indicates that dynamin and
dynamin-related proteins are involved both in pathology and protection against
human diseases. The most interesting are dynamin-like Mx proteins exhibiting
antiviral activity. |
| Address and Contact Information |
Nencki Institute of Experimental Biology, Pasteura 3, 02-093 Warszawa, Poland |
|
| Volume 7 (2002) pp 1081-1086 |
| Title |
THIORIDAZINE INDUCES ERYTHROCYTE STOMATOCYTOSIS
DUE TO INTERACTIONS WITH NEGATIVELY CHARGED LIPIDS |
| Authors |
Andrzej B. Hendrich, Katarzyna Lichacz, Anna Burek and Krystyna Michalak |
| Abstract |
Despite the fact that thioridazine is used clinically as a neuroleptic
drug, little is known about the molecular mechanisms underlying its biological
effects, in particular about its interactions with membranes. In the present work
we investigate the influence of thioridazine on model and cell membranes, using
calorimetry, DPH fluorescence polarization measurements, studies of
haemolysis and scanning electron microscopy. The experiments show that
thioridazine interacts with lipid bilayers and intercalates into bilayer structure.
We found that erythrocyte stomatocytosis induced by the drug might be related
to preferential interaction of thioridazine with charged lipids. |
| Address and Contact Information |
Department of Biophysics, Wrocław Medical University,
Chałubińskiego 10, 50-368 Wrocław, Poland |
|
| Volume 7 (2002) pp 1087-1094 |
| Title |
THE INTERACTION OF TRYPTOPHAN AND ANS WITH PAMAM
DENDRIMERS |
| Authors |
Barbara Klajnert and Maria Bryszewska* |
| Abstract |
Dendrimers are globular, hyperbranched polymers possessing a high
concentration of surface functional groups and internal cavities. These unique
features make them very useful in many biomedical applications, especially as
carrier molecules. In this study, the interaction of tryptophan and 1-
anilinonaphthalene-8-sulfonic acid with three types of polyamidoamine
dendrimers was examined. It was observed that the type of dendrimer surface
group has a strong impact on the interactions between the dendrimers and
fluorescent molecules. |
| Address and Contact Information |
Department of General Biophysics, University of Łódź, Banacha 12/16,
90-237 Łódź, Poland
* Corresponding author, E-mail: marbrys@biol.uni.lodz.pl |
|
| Volume 7 (2002) pp 1095-1109 |
| Title |
THE INFLUENCE OF MEMBRANE LIPID METABOLITES ON
LYMPHOCYTE POTASSIUM CHANNEL ACTIVITY |
| Authors |
Andrzej Teisseyre1, Krystyna Michalak1 and Małgorzata Kuliszkiewicz-Janus2 |
| Abstract |
In the present study, the whole-cell patch-clamp technique was
applied to elucidate modulatory effects of high-density lipoproteins (HDL),
sphingosine (SPH), sphingosine-1-phosphate (SPP), lysophosphatidic acid
(LPA) and sphingosyl- phosphorylcholine (SPC) on the activity of Kv1.3
channels in human T lymphocytes (TL). Obtained data provide evidence that
application of SPC at micromolar concentrations shifts the channel activation
midpoint by about 20 mV towards positive membrane potentials. This effect
occurs in a concentration-dependent manner and is saturated at SPC
concentrations higher than 10 mM. The shift of channel activation midpoint is
accompanied by a pronounced slowing of the activation kinetics. The
modulatory effect of SPC is clearly voltage-dependent, being most potent at –20
mV and least potent at +60 mV. The steady-state inactivation curve is also
shifted by about 20 mV towards positive membrane potentials. The kinetics of
channel inactivation and deactivation (closure) remain unaffected upon SPC
treatment. In contrast, application of HDL (250 mg/ml), SPH (50 and 100 mM),
SPP (10 mM) and LPA (10 and 36 mM) does not exert any modulatory effect on
the channel activity. The effect of SPC on Kv1.3 channel gating resembles the
effect exerted by extracellular zinc at the concentration of 10 mM. It is concluded
that the effect of SPC is specific and may be due to the presence of a choline
residue in SPC molecules. The possible mechanism and the physiological
significance of this modulatory effect on Kv1.3 channels are discussed. |
| Address and Contact Information |
1Department of Biophysics, Wrocław Medical University, Chałubińskiego 10,
50-368 Wrocław, Poland,
2Department and Clinic of Haematology and
Oncology, Wrocław Medical University, Pasteura 4, 50-367 Wrocław, Poland |
|
| Volume 7 (2002) pp 1111-1120 |
| Title |
THE EFFECTS OF GROWTH REGULATORS ON SOMACLONAL
VARIATION IN RYE (Secale cereale L.) AND SELECTION OF
SOMACLONAL VARIANTS WITH INCREASED AGRONOMIC
TRAITS |
| Authors |
Monika Rakoczy-Trojanowska |
| Abstract |
The aim of this research was to characterize somaclonal variation in
populations derived from embryos cultured on two types of induction medium
(supplemented with either 2,4-D or dicamba), as well as to select and
characterize several somaclonal lines.. The sexual progenies of 40 R0
regenerants - A somaclones (derived on the medium with 2,4-D) and B
somaclones (derived on the medium with dicamba) - were analysed according to
the following traits: plant height, total number of tillers, number of productive
tillers, spike length, number of spikelets per spike, spike compactness, number
of normally developed grains per spike, weight of grains per spike, and the
weight of 1000 grains. The results for twenty-two R1 plants surpassed the
variability range for the control. The transmission of positive changes to the next
generation was proved in the case of 8 originally chosen R1 plants: 7 plants
selected from the A somaclones and one plant from the B somaclones. Five out
of the eight created somaclonal lines proved to be stable somaclonal variants.
The absolute rate of the efficiency of positive somaclonal changes was
calculated as 0.64%. |
| Address and Contact Information |
Department of Plant Genetics, Breeding and Biotechnology, Warsaw
Agricultural University, Nowoursynowska 166, 02-787 Warszawa, Poland
* E-mail: RAKOCZY@ALPHA.SGGW.WAW.PL
|
|
| Volume 7 (2002) pp 1121-1129 |
| Title |
LYSOSOMOTROPIC N,N- DIMETHYL a-AMINOACID n-ALKYL
ESTERS AND THEIR QUATERNARY AMMONIUM SALTS AS
PLASMA MEMBRANE AND MITOCHONDRIAL ATPases
INHIBITORS |
| Authors |
Ewa Obłąk1, Tadeusz M. Lachowicz2, Jacek Łuczyński3 and Stanisław Witek3 |
| Abstract |
A set of n-alkyl esters of N,N-dimethylglycine (DMG-n) and their
methobromides (DMGM-n) was synthesized, and their activities on yeast
Saccharomyces cerevisiae were compared. The compounds differ in the number
of carbon atoms in the aliphatic chain. Aminoesters with 12 carbon atoms
appeared to be most active. Unlike quaternary ammonium salts previously
tested, the activities of the compounds were not pH-dependent; the minimal
inhibitory concentrations (MIC) were identical at pH 8 and at pH 6. In contrast
to quaternary ammonium salts, aminoesters showed similar effects on
respiratory sufficient (rho+) and respiratory deficient (rhoo) mutants.
When tested on glucose stimulated proton extrusion, aminoesters applied at MIC
increased external pH. Aminoesters inhibited the plasma membrane H+-ATPase,
whereas they were less inhibitory on the mitochondrial ATPase.
In order to further compare the aminoesters and their corresponding quaternary
ammonium salts, derivatives of N,N-dimethylalanine (DMAL-n and DMALMn,
respectively) were synthesized. The quaternary ammonium salts appeared to
have a higher inhibitory potency than aminoesters, especially at pH 8, and
alanine derivatives inhibited growth at a lower concentration than glycine
derivatives. Both alanine derivatives of the aminoester and the quaternary
ammonium salt inhibited the plasma membrane H+- ATPase at lower
concentrations than glycine derivatives, but the alanine aminoester was without a
detectable effect on the mitochondrial ATPase. |
| Address and Contact Information |
1Institute of Microbiology, University of Wrocław, Przybyszewskiego 65/73,
51-148 Wrocław, Poland,
2Institute of Biotechnology and Environmental Protection,
University of Zielona Góra, Monte Cassino 3a, 65-561 Zielona Góra,
Poland,
3Department of Chemistry, Technical University of Wrocław,
51-148 Wrocław, Poland |
|
| Volume 7 (2002) pp 1131-1136 |
| Title |
THE ADJUVANT ACTIVITY OF LACTOFERRIN IN THE
GENERATION OF DTH TO OVALBUMIN CAN BE INHIBITED BY
BOVINE SERUM ALBUMIN BEARING α-D-MANNOPYRANOSYL
RESIDUES |
| Authors |
Maja Kocięba1, Michał‚ Zimecki1, Marian Kruzel2 and Jeffrey Actor2 |
| Abstract |
Lactoferrin (LF) is an iron-binding glycoprotein present in the
cytoplasmic granules of neutrophils and in external secretions of mammals.
Although the biological role of human and bovine lactoferrin has been
extensively studied, there is still uncertainty as to the nature and function of
lactoferrin receptors. We recently determined that methyl-α-D-mannopyranoside
given intraperitoneally (i.p.) could suppress the adjuvant activity of LF in the
generation of delayed-type hypersensitivity (DTH) to ovalbumin (OVA). We
concluded that the lactoferrin effects in DTH are mediated by carbohydraterecognizing
receptors like the mannose receptor (MR). This study indicates that
subcutaneous (s.c.) administration of very small doses of the Man-bovine serum
albumin (Man-BSA) complex, together with a sensitizing dose of the antigen,
gives the same effects as i.p. administration of methyl-α-D-mannopyranoside.
The latter is also a blocker of MR, although of a much lower affinity to the
receptor than Man-BSA. The blocking of the adjuvant effect of LF by the Man-
BSA complex (when given together with the sensitising dose of antigen)
suggests that the function of antigen-presenting cells in the skin (presumably
immature dendritic cells expressing MR) is inhibited. The results of our study
indicate that a receptor with an affinity for mannose is essential for the
mediation of adjuvant lactoferrin function in the generation of DTH. |
| Address and Contact Information |
1Department of Experimental Therapy, Institute of Immunology and
Experimental Therapy, Polish Academy of Sciences, Weigla 12, 53-114
Wrocław, Poland,
2University of Texas, Houston Health Science Center at
Huston, MSB 4.506, 6431 Fannin Street, Houston, TX 77030, USA |
|
| Volume 7 (2002) pp 1137-1151 |
| Title |
THE ROLE OF CELL WALL IN PLANT EMBRYOGENESIS |
| Authors |
Robert Malinowski* and Marcin Filipecki |
| Abstract |
This review presents recent data about cell wall involvement in plant
embryogenesis. During plant development, the cell wall is subjected to precise
regulation. During this process a bidirectional information exchange between the
cell wall and the protoplast is observed. The cell wall also mediates in the cellcell
(apoplastic) and cell to cell (symplastic) information flow. Especially some
products derived from the hydrolysis of specific cell wall compounds can act as
short distance signal transduction molecules during the development.
Oligosaccharins are a group of such products. Their activity and sources focused
the researchers' attention on the biochemical composition of the cell wall and
the activity of some cell wall enzymes. The dramatic influence on the embryo
body shape has also the cell wall synthesis machinery, including vesicular
secretion pathways. Moreover, the interplay between the turgor pressure and
counteracting cell walls and neighbouring cells (in higher organisms) creates the
specific mechanical forces influencing the development of the whole plant. We
conclude that discovering factors which can influence cell wall physiology and
architecture is crucial for a better understanding of plant embryogenesis. In this
review we summarize some recent experimental data reporting plant cell wall
involvement in embryogenesis, putting special emphasis on somatic
embryogenesis. |
| Address and Contact Information |
Department of Plant Genetics, Breeding and Biotechnology,
Warsaw Agricultural University, Poland
* Corresponding author, E-mail: Syrop@netscape.net |
|
| Volume 7 (2002) pp 1153-1157 |
| Title |
NATRIURETIC PEPTIDES REDUCE PLASMINOGEN ACTIVATOR
INHIBITOR-1 EXPRESSION IN HUMAN ENDOTHELIAL CELLS |
| Authors |
Zofia Pawłowska1*, Hanna Jerczyńska1, Janusz Szemraj2, Patrycja Barańska1, Maria Świątkowska1 and Czesław S. Cierniewski1 |
| Abstract |
Plasma concentrations of natriuretic peptides increase in some
pathological conditions, but very little is known about the effect of these
vasodilator peptides on the regulation of the blood coagulation system. The
fundamental role in the regulation of fibrinolysis is played by plasminogen
activator inhibitor type 1 (PAI-1). Recent studies demonstrate that natriuretic
peptides can modulate PAI-1 expression in bovine aortic smooth muscle cells
and rat aortic endothelial cells. In this report, we tested the effect of natriuretic
peptides on PAI-1 expression in the human endothelial cell line (EA.hy 926).
For this purpose, we treated the cell cultures with ANP, BNP and CNP, and
modulation of PAI-1 synthesis was evaluated. We compared the effect of
natriuretic peptides on synthesis and release of PAI-1 in unstimulated cells, and
after activation with tumour necrosis factor a (TNFa). Natriuretic peptides
abolished TNFa- induced upregulation of PAI-1 expression at both the PAI-1
mRNA and the antigen levels. The inhibitory efficiency was higher in the case
of CNP when compared to that produced by ANP and BNP, particularly when
TNFa-stimulated cells were used. We observed an inhibition of stimulatory
effect of TNFa on PAI-1 expression also at the level of the PAI-1 promoter in
cells transfected with a PAI-1 promoter fragment (+71 to -800) [1]. The PAI-1
promoter activity was markedly inhibited by C-type natriuretic peptide, already
at a very low (0.001 mM) concentration of the peptide. |
| Address and Contact Information |
1Department of Molecular and Medical Biophysics,
2Department of
Biochemistry, Medical University of Łódź, Poland
* Corresponding author, E-mail: pawlow@zdn.am.lodz.pl |
|
