Wyniki wyszukiwania - Biblioteka Nauki

1

Cell wall proteome of pathogenic fungi

100%

Karkowska-Kuleta J. , Kozik A.

Acta Biochimica Polonica

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2015

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tom 62

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nr 3

339-351

EN

A fast development of a wide variety of proteomic techniques supported by mass spectrometry coupled with high performance liquid chromatography has been observed in recent years. It significantly contributes to the progress in research on the cell wall, very important part of the cells of pathogenic fungi. This complicated structure composed of different polysaccharides, proteins, lipids and melanin, plays a key role in interactions with the host during infection. Changes in the set of the surface-exposed proteins under different environmental conditions provide an effective way for pathogens to respond, adapt and survive in the new niches of infection. This work summarizes the current state of knowledge on proteins, studied both qualitatively and quantitatively, and found within the cell wall of fungal pathogens for humans, including Candida albicans, Candida glabrata, Aspergillus fumigatus, Cryptococcus neoformans and other medically important fungi. The described proteomic studies involved the isolation and fractionation of particular sets of proteins of interest with various techniques, often based on differences in their linkages to the polysaccharide scaffold. Furthermore, the proteinaceous contents of extracellular vesicles ("virulence bags") of C. albicans, C. neoformans, Histoplasma capsulatum and Paracoccidioides brasiliensis are compared, because their production can partially explain the problem of non-classical protein secretion by fungi. The role assigned to surface-exposed proteins in pathogenesis of fungal infections is enormously high, thus justifying the need for further investigation of cell wall proteomes.

2

Bradykinin B2 receptor and dopamine D2 receptor cooperatively contribute to the regulation of neutrophil adhesion to endothelial cells

80%

Niewiarowska-Sendo A. , Łabędź-Masłowska A. , Kozik A. , Guevara-Lora I.

Acta Biochimica Polonica

|

2018

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tom 65

|

nr 3

367-375

EN

Leukocyte adhesion to the vascular endothelium contributes to many immunological and inflammatory disorders. These processes have been shown to be mediated by bradykinin receptor type 2 (B2R) and dopamine receptor type 2 (D2R). In a previous study, we reported the formation of a B2R-D2R heterodimer, possibly altering cellular functions. Hence, in the present study, we examined the effect of co-activation of endothelial cells with B2R and D2R agonists on the interaction of these cells with neutrophils. Bradykinin, the main B2R agonist, significantly increased cell adhesion, and this effect was reversed when the endothelial cells were additionally co-treated with a selective D2R agonist, sumanirole. These results were dependent on the incubation time, showing an opposite tendency after prolonged stimulation. Significant changes in the expression of adhesion proteins, such as E-selectin and intercellular adhesion molecule 1 in endothelial cells were observed. Additionally, the cells preincubated with tumor necrosis factor-α showed decreased cell adhesion and IL-8 release after long incubation with both agonists. The modulation of cell adhesion by D2R and B2R seem to be mediated via STAT3 phosphorylation. In summary, this study demonstrated a protective role of D2R in neutrophil-endothelial cell adhesion induced by bradykinin, especially in cytokine-stimulated endothelial cells.

3

Kinin-generating cellular model obtained from human glioblastoma cell line U-373

80%

Guevara-Lora I. , Blonska B. , Faussner A. , Kozik A.

Acta Biochimica Polonica

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2013

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tom 60

|

nr 3

299-305

EN

Kinins, a group of important pro-inflammatory peptides, are abundantly found in tissues and biological fluids of cancer patients. Bradykinin, the major representative of kinins, induces vascular permeability and, in consequence, promotes tumor expansion. Additionally, the kinin-induced inflammatory responses, especially those mediated by kinin metabolites without the C-terminal arginine residue, lead to enhanced tumor growth. The present study aimed at analyzing the ability of the human glioblastoma cell line U-373, derived from a malignant tumor, to produce kinin peptides. The proteins involved in kinin generation, i.e., the kininogens and the kallikreins, were shown to be expressed in these cells. Moreover, tumor necrosis factor α, a proinflammatory cytokine that mediates tumorigenesis, was found to enhance the expression of enzymes associated with kinin production. The strong binding of kininogen to the cell surface and the enzymatic degradation of this protein by cells suggest the activation of kinin-generating systems. Indeed, glioblastoma cells, pre-treated with tumor necrosis factor α, released kinin peptides from exogenous kininogen. The expression of kinin receptors in these cells was also shown to increase under the influence of this cytokine. Our results suggest that the human glioblastoma cell line U-373 constitutes a good cellular model that can be helpful in cancer research focused on kinin-induced inflammation. Furthermore, our findings can contribute to new approaches in cancer treatment with the use of kinin receptor antagonists and inhibitors of kinin production.

4

Fungi pathogenic to humans: molecular bases of virulence of Candida albicans, Cryptococcus neoformans and Aspergillus fumigatus

80%

Karkowska-Kuleta J. , Rapala-Kozik M. , Kozik A.

Acta Biochimica Polonica

|

2009

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tom 56

|

nr 2

211-224

EN

The frequency of severe systemic fungal diseases has increased in the last few decades. The clinical use of antibacterial drugs, immunosuppressive agents after organ transplantation, cancer chemotherapy, and advances in surgery are associated with increasing risk of fungal infections. Opportunistic pathogens from the genera Candida and Aspergillus as well as pathogenic fungi from the genus Cryptococcus can invade human organism and may lead to mucosal and skin infections or to deep-seated mycoses of almost all inner organs, especially in immunocompromised patients. Nowadays, there are some effective antifungal agents, but, unfortunately, some of the pathogenic species show increasing resistance. The identification of fungal virulence factors and recognition of mechanisms of pathogenesis may lead to development of new efficient antifungal therapies. This review is focused on major virulence factors of the most common fungal pathogens of humans: Candida albicans, Aspergillus fumigatus and Cryptococcus neoformans. The adherence to host cells and tissues, secretion of hydrolytic enzymes, phenotypic switching and morphological dimorphism contribute to C. albicans virulence. The ability to grow at 37°C, capsule synthesis and melanin formation are important virulence factors of C. neoformans. The putative virulence factors of A. fumigatus include production of pigments, adhesion molecules present on the cell surface and secretion of hydrolytic enzymes and toxins.

5

Characterization of thiamine uptake and utilization in Candida spp. subjected to oxidative stress

80%

Wolak N. , Tomasi M. , Kozik A. , Rapala-Kozik M.

Acta Biochimica Polonica

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2015

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tom 62

|

nr 3

445-455

EN

Candida species are associated with an increasing number of life-threatening infections (candidiases), mainly due to the high resistance of these yeast-like fungi to antifungal drugs and oxidative stress. Recently, thiamine (vitamin B1) was found to alleviate stress responses in Saccharomyces cerevisiae; however, thiamine influence on defense systems in pathogenic fungi has never been investigated. The current work was aimed to elucidate the role of thiamine in stress reactions of C. albicans, C. glabrata, C. tropicalis and C. dubliniensis, subjected to hydrogen peroxide treatment. As compared to S. cerevisiae, Candida strains exposed to oxidative stress showed: (i) a much higher dependence on exogenous thiamine; (ii) an increased demand for thiamine diphosphate (TDP) and TDP-dependent enzyme, transketolase; (iii) no changes in gene expression of selected stress markers - superoxide dismutase and catalase - depending on thiamine availability in medium; (iv) a similar decrease of reactive oxygen species (ROS) generation in the presence of thiamine. Moreover, the addition of therapeutic doses of thiamine to yeast culture medium revealed differences in its accumulation between various Candida species. The current findings implicate that the protective action of thiamine observed in S. cerevisiae differs significantly form that in pathogenic Candida strains, both in terms of the cofactor functions of TDP and the effects on fungal defense systems.

6

Selected mucolytic, anti-inflammatory and cardiovascular drugs change the ability of neutrophils to form extracellular traps (NETs)

80%

Zawrotniak M. , Kozik A. , Rapala-Kozik M.

Acta Biochimica Polonica

|

2015

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tom 62

|

nr 3

465-473

EN

Neutrophils form the first line of host defense against infections that combat pathogens using two major mechanisms, the phagocytosis or the release of neutrophil extracellular traps (NETs). The netosis (NET formation) exerts additional, unfavorable effects on the fitness of host cells and is also involved at the sites of lung infection, increasing the mucus viscosity and in the circulatory system where it can influence the intravascular clot formation. Although molecular mechanisms underlying the netosis are still incompletely understood, a role of NADPH oxidase that activates the production of reactive oxygen species (ROS) during the initiation of NETs has been well documented. Since several commonly used drugs can affects the netosis, our current study was aimed to determine the effects of selected mucolytic, anti-inflammatory and cardiovascular drugs on NET formation, with a special emphasis on ROS production and NADPH oxidase activity. The treatment of neutrophils with N-acetylcysteine, ketoprofen and ethamsylate reduced the production of ROS by these cells in a dose-dependent manner. NET formation was also modulated by selected drugs. N-acetylcysteine inhibited the netosis but in the presence of H2O2 this neutrophil ability was restored, indicating that N-acetylcysteine may influence the NET formation by modulating ROS productivity. The administration of ethamsylate led to a significant reduction in NET formation and this effect was not restored by H2O2 or S. aureus, suggesting the unexpected additional side effects of this drug. Ketoprofen seemed to promote ROS-independent NET release, simultaneously inhibiting ROS production. The results, obtained in this study strongly suggest that the therapeutic strategies applied in many neutrophil-mediated diseases should take into account the NET-associated effects.

7

Surfaceome of pathogenic yeasts, Candida parapsilosis and Candida tropicalis, revealed with the use of cell surface shaving method and shotgun proteomic approach

80%

Karkowska-Kuleta J. , Zajac D. , Bochenska O. , Kozik A.

Acta Biochimica Polonica

|

2015

|

tom 62

|

nr 4

807-819

EN

In the course of infections caused by pathogenic yeasts from the genus Candida, the fungal cell surface is the first line of contact with the human host. As the surface-exposed proteins are the key players in these interactions, their identification can significantly contribute to discovering the mechanisms of pathogenesis of two emerging pathogens from this genus, C. parapsilosis and C. tropicalis. Therefore, the aim of the present study was to identify the cell wall-attached proteins of these two species with the use of cell surface shaving and a shotgun proteomic approach. Different morphological forms of C. parapsilosis and C. tropicalis cells obtained after growth under various conditions were subjected to this treatment. This allowed to indicate the most abundant cell surface proteins on the basis of the normalized spectral abundance factors. In case of yeast-like forms these were, among others, proteins similar to a chitinase, glyceraldehyde-3-phosphate dehydrogenase and an inducible acid phosphatase for C. parapsilosis, and a constitutive acid phosphatase, pyruvate decarboxylase and glyceraldehyde-3-phosphate dehydrogenase for C. tropicalis. In case of pseudohyphal forms, proteins similar to a cell surface mannoprotein Mp65, chitinase and glycosylphosphatidylinositol-anchored transglycosylase Crh11 were identified at the cell surface of C. parapsilosis. The Rbt1 cell wall protein, a hyphally regulated cell wall protein and proteins from agglutinin-like sequence protein family were found as the most abundant on C. tropicalis pseudohyphae. Apart from the abovementioned proteins, several additional covalently bound and atypical cell wall proteins were also identified. These results extend the current knowledge regarding the molecular basis of virulence of these two non-albicans Candida species.

8

Hypothetical orchestrated cooperation between dopaminergic and kinin receptors for the regulation of common functions

80%

Guevara-Lora I. , Niewiarowska-Sendo A. , Polit A. , Kozik A.

Acta Biochimica Polonica

|

2016

|

tom 63

|

nr 3

387-396

EN

The G protein-coupled receptors (GPCRs), one of the largest protein families, are essential components of the most commonly used signal-transduction systems in cells. These receptors, often using common pathways, may cooperate in the regulation of signal transmission to the cell nucleus. Recent scientific interests increasingly focus on the cooperation between these receptors, particularly in a context of their oligomerization, e.g. the formation of dimers that are able to change characteristic signaling of each receptor. Numerous studies on kinin and dopamine receptors which belong to this family of receptors have shown new facts demonstrating their direct interactions with other GPCRs. In this review, current knowledge on signaling pathways and oligomerization of these receptors has been summarized. Owing to the fact that kinin and dopamine receptors are widely expressed in cell membranes where they act as mediators of numerous common physiological processes, the information presented here sheds new light on a putative crosstalk of these receptors and provides more comprehensive understanding of possible direct interactions that may change their functions. The determination of such interactions may be useful for the development of new targeted therapeutic strategies against many disorders in which kinin and dopamine receptors are involved.

9

The effect of differentiation agents on inflammatory and oxidative responses of the human neuroblastoma cell line SK-N-SH

80%

Niewiarowska-Sendo A. , Patrzalek K. , Kozik A. , Guevara-Lora I.

Acta Biochimica Polonica

|

2015

|

tom 62

|

nr 3

435-443

EN

Obtaining a suitable experimental cellular model is a major problem for neuroscience studies. Neuroblastoma cell lines have been often applied in studies related to pathological disorders of nervous system. However, in the search for an ideal model, these cells must be differentiated to cancel their tumor character. The subsequent reactions that are caused by differentiation are not always indifferent to the same model. We evaluated the effect of two well known substances, used for SH-N-SK cell line differentiation, retinoic acid (RA) and phorbol-12-myristate-13-acetate (PMA), on the induction of pro-inflammatory and pro-oxidative reactions in these cells. Cells differentiated with PMA were able to produce significantly higher amounts of pro-inflammatory cytokines whereas the release of nitric oxide radicals was similar to that in undifferentiated cells. On the contrary, in RA-differentiated cells no significant changes in cytokine production were observed and the nitric oxide release was decreased. Additionally, the RA-differentiated neuronal model was more sensible to lipopolysaccharide stimulation, producing pro-inflammatory cytokines abundantly. These results suggest that RA-differentiated SH-N-SK cells provide a more suitable experimental model for the study of molecular and cellular mechanisms of the inflammation and oxidative stress in neuronal cells.

10

80%

Guevara-Lora I. , Florkowska M. , Kozik A.

Acta Biochimica Polonica

|

2009

|

tom 56

|

nr 3

515-522

EN

Kinins, universal mediators of inflammation, are recognized by two kinds of receptors, B1 and B2, which have been found to be expressed in numerous cell types of several species. However, the knowledge of the regulation of these receptors in leukocytes is still not satisfactory. In the current work, we have demonstrated a constitutive production of B2 receptor mRNA in the human promonocyte U937 cells and its two-fold augmentation after cell differentiation with retinoic acid and phorbol ester. Bradykinin and des-Arg10-kallidin induced the expression of both B2 and B1 receptors in cells before and after differentiation. Generally, the undifferentiated cells were more susceptible to bradykinin-dependent induction of kinin receptors (increases by approximately 250% and 200% for B2 and B1 receptors, respectively). The induction, by approx. 200%, of B1 receptor by des-Arg10-kallidin was detected on both mRNA and protein levels. In addition, an unexpected strong induction of B2 receptor by this compound was observed in the retinoic acid- and phorbol ester-differentiated cells (by 150% and 200%, respectively) that suggests a possible autoregulation of kinin receptors by own agonists during the inflammatory state. On the other hand, a strong enhancement of the expression of both receptors by interleukin 1β, especially in the phorbol ester-differentiated cells, indicates the involvement of kinin receptors in the propagation of the inflammatory processes.

11

Interaction of human fibronectin with Candida glabrata epithelial adhesin 6 (Epa6)

71%

Zajac D. , Karkowska-Kuleta J. , Bochenska O. , Rapala-Kozik M. , Kozik A.

Acta Biochimica Polonica

|

2016

|

tom 63

|

nr 3

417-426

EN

Adherence of pathogens to extracellular matrix proteins and host cells is one of the essential steps in the microbial colonization of the human organism. The adhesion of C. glabrata, i.e. the second major causative agent of human disseminated candidiases after C. albicans, to the host epithelium mainly engages specific fungal cell wall proteins - epithelial adhesins (Epa) - in particular, Epa1, Epa6 and Epa7. The aim of the present study was to identify the major Epa protein involved in the interactions with the human extracellular matrix protein - fibronectin - and to present the kinetic and thermodynamic characteristics of these interactions. A relatively novel gel-free approach, i.e. the "cell surface shaving" that consists in short treatment of fungal cells with trypsin was employed to identify the C. glabrata surfaceome. Epa6 was purified, and the isolated protein was characterized in terms of its affinity to human fibronectin using a microplate ligand-binding assay and surface plasmon resonance measurements. The dissociation constants for the binding of Epa6 to fibronectin were determined to range between 9.03 × 10-9 M and 7.22 × 10-8 M, depending on the method used (surface plasmon resonance measurements versus the microplate ligand-binding assay, respectively). The identified fungal pathogen-human host protein-protein interactions might become a potential target for novel anticandidal therapeutic approaches.

12

Properties of chemically oxidized kininogens.

71%

Niziołek M. , Kot M. , Pyka K. , Mak P. , Kozik A.

Acta Biochimica Polonica

|

2003

|

tom 50

|

nr 3

753-763

EN

Kininogens are multifunctional proteins involved in a variety of regulatory processes including the kinin-formation cascade, blood coagulation, fibrynolysis, inhibition of cysteine proteinases etc. A working hypothesis of this work was that the properties of kininogens may be altered by oxidation of their methionine residues by reactive oxygen species that are released at the inflammatory foci during phagocytosis of pathogen particles by recruited neutrophil cells. Two methionine-specific oxidizing reagents, N-chlorosuccinimide (NCS) and chloramine-T (CT), were used to oxidize the high molecular mass (HK) and low molecular mass (LK) forms of human kininogen. A nearly complete conversion of methionine residues to methionine sulfoxide residues in the modified proteins was determined by amino acid analysis. Production of kinins from oxidized kininogens by plasma and tissue kallikreins was significantly lower (by at least 70%) than that from native kininogens. This quenching effect on kinin release could primarily be assigned to the modification of the critical Met-361 residue adjacent to the internal kinin sequence in kininogen. However, virtually no kinin could be formed by human plasma kallikrein from NCS-modified HK. This observation suggests involvement of other structural effects detrimental for kinin production. Indeed, NCS-oxidized HK was unable to bind (pre)kallikrein, probably due to the modification of methionine and/or tryptophan residues at the region on the kininogen molecule responsible for the (pro)enzyme binding. Tests on papain inhibition by native and oxidized kininogens indicated that the inhibitory activity of kininogens against cysteine proteinases is essentially insensitive to oxidation.

13

The action of ten secreted aspartic proteases of pathogenic yeast Candida albicans on major human salivary antimicrobial peptide, histatin 5

61%

Bochenska O. , Rapala-Kozik M. , Wolak N. , Aoki W. , Ueda M. , Kozik A.

Acta Biochimica Polonica

|

2016

|

tom 63

|

nr 3

403-410

EN

Candida albicans, belonging to the most common fungal pathogens of humans, exploits many virulence factors to infect the host, of which the most important is a family of ten secreted aspartic proteases (Saps) that cleave numerous peptides and proteins, often deregulating the host's biochemical homeostasis. It was recently shown that C. albicans cells can inactivate histatin5 (His5), a salivary histidine-rich anticandidal peptide, through the hydrolytic action of Saps. However, the current data on this subject are incomplete as only four out of ten Saps have been studied with respect to hydrolytic processing of His5 (Sap2, Sap5, Sap9-10). The aim of the study was to investigate the action of all Saps on His5 and to characterize this process in terms of peptide chemistry. It was shown that His5 was degraded by seven out of ten Saps (Sap1-4, Sap7-9) over a broad range of pH. The cleavage rate decreased in an order of Sap2>Sap9>Sap3>Sap7>Sap4>Sap1>Sap8. The degradation profiles for Sap2 and Sap9 were similar to those previously reported; however, in contrast to the previous study, Sap10 was shown to be unable to cleave His5. On a long-time scale, the peptide was completely degraded and lost its antimicrobial potential but after a short period of Sap treatment several shorter peptides (His1-13, His1-17, His1-21) that still decreased fungal survival were released. The results, presented hereby, provide extended characteristics of the action of C. albicans extracellular proteases on His5. Our study contribute to deepening the knowledge on the interactions between fungal pathogens and the human host.

14

Kinetic and thermodynamic characterization of the interactions between the components of human plasma kinin-forming system and isolated and purified cell wall proteins of Candida albicans

61%

Seweryn K. , Karkowska-Kuleta J. , Wolak N. , Bochenska O. , Kedracka-Krok S. , Kozik A. , Rapala-Kozik M.

Acta Biochimica Polonica

|

2015

|

tom 62

|

nr 4

825-835

EN

Cell wall proteins of Candida albicans, besides their best known role in the adhesion of this fungal pathogen to host's tissues, also bind some soluble proteins, present in body fluids and involved in maintaining the biochemical homeostasis of the human organism. In particular, three plasma factors - high-molecular-mass kininogen (HK), factor XII (FXII) and prekallikrein (PPK) - have been shown to adhere to candidal cells. These proteins are involved in the surface-contact-catalyzed production of bradykinin-related peptides (kinins) that contribute to inflammatory states associated with microbial infections. We recently identified several proteins, associated with the candidal cell walls, and probably involved in the binding of HK. In our present study, a list of potential FXII- and PPK-binding proteins was proposed, using an affinity selection (on agarose-coupled FXII or PPK) from a whole mixture of β-1,3-glucanase-extrated cell wall-associated proteins and the mass-spectrometry protein identification. Five of these fungal proteins, including agglutinin-like sequence protein 3 (Als3), triosephosphate isomerase 1 (Tpi1), enolase 1 (Eno1), phosphoglycerate mutase 1 (Gpm1) and glucose-6-phosphate isomerase 1 (Gpi1), were purified and characterized in terms of affinities to the human contact factors, using the surface plasmon resonance measurements. Except Gpm1 that bound only PPK, and Als3 that exhibited an affinity to HK and FXII, the other isolated proteins interacted with all three contact factors. The determined dissociation constants for the identified protein complexes were of 10-7 M order, and the association rate constants were in a range of 104-105 M-1s-1. The identified fungal pathogen-host protein interactions are potential targets for novel anticandidal therapeutic approaches.

15

Binding of human plasminogen and high-molecular-mass kininogen by cell surface-exposed proteins of Candida parapsilosis

61%

Karkowska-Kuleta J. , Zajac D. , Bras G. , Bochenska O. , Rapala-Kozik M. , Kozik A.

Acta Biochimica Polonica

|

2017

|

tom 64

|

nr 3

391-400

EN

Pathogenic microbes can recruit to their cell surface human proteins that are components of important proteolytic cascades involved in coagulation, fibrinolysis and innate immune response. Once located at the bacterial or fungal surface, such deployed proteins might be utilized by pathogens to facilitate invasion and dissemination within the host organism by interfering with functionality of these systems or by exploiting specific activity of the bound enzymes. Aim of the study presented here was to characterize this phenomenon in Candida parapsilosis (Ashford) Langeron et Talice - an important causative agent of systemic fungal infections (candidiases and candidemias) in humans. We have investigated the interactions of fungal surface-exposed proteins with plasminogen (HPG) and high-molecular-mass kininogen (HK) - the crucial components of human fibrinolytic system and proinflammatory/procoagulant contact-activated kinin-forming system, respectively. After confirming ability of the fungal surface-exposed proteins to bind HPG and HK, four of them - two agglutinin-like sequence (Als) proteins CPAR2_404780 and CPAR2_404800, a heat shock protein Ssa2 and a moonlighting protein 6-phosphogluconate dehydrogenase 1 - were purified using ion-exchange chromatography, gel filtration and chromatofocusing. Then, their affinities to HPG and HK were characterized with surface plasmon resonance measurements. The determined dissociation constants for the investigated protein-protein complexes were within a 10-7 M order for the HPG binding and in a range of 10-8-10-9 M for the HK binding. Detailed characterization of adsorption of these two important plasma proteins on the fungal cell surface may help to increase our understanding of molecular mechanisms of C. parapsilosis-dependent candidiasis.

16

New method for quantitative analysis of GD2 ganglioside in plasma of neuroblastoma patients

51%

Czaplicki D. , Horwacik I. , Kowalczyk A. , Wieczorek A. , Bolek-Marzec K. , Balwierz W. , Kozik A. , Rokita H.

Acta Biochimica Polonica

|

2009

|

tom 56

|

nr 3

423-431

EN

Neuroblastoma, the most common extracranial solid tumour of childhood, is a malignancy of unknown origin and non-specific symptoms. One of the markers of the disease is GD2 ganglioside (disialoganglioside), which is abundantly expressed on the surface of neuroblastoma cells. Gangliosides are known to be shed by tumour cells and this phenomenon can be significant in cancer progression as they inhibit a number of immune responses both in vitro and in vivo. In search for novel markers useful in monitoring and prognosis of neuroblastoma, we developed and validated a new quantitative method of GD2 ganglioside analysis in human blood plasma. We evaluated the level of gangliosides in blood serum of 34 neuroblastoma patients using high-performance liquid chromatography. The technique was used to detect fluorescently labelled oligosaccharides derived from serum glycosphingolipids by enzymatic digestion with ceramide glycanase. The developed method allowed determination of GD2 concentrations at the picomole level and required only 40 µl of plasma, which should be particularly useful when the quantity of clinical material is limiting. Moreover, this method can be applied to study concentration of other gangliosides, as shown for GD3 ganglioside. Analysis of plasma samples from the 34 neuroblastoma patients did not reveal any correlations between the concentration of GD2 ganglioside and clinical parameters, including the results of therapy; it showed, however, that the concentration of GD2 ganglioside in the plasma of neuroblastoma patients decreased substantially in the course of treatment.

17

Characterization of the interactions between human high-molecular-mass kininogen and cell wall proteins of pathogenic yeasts Candida tropicalis

51%

Karkowska-Kuleta J. , Zajac D. , Bras G. , Bochenska O. , Seweryn K. , Kedracka-Krok S. , Jankowska U. , Rapala-Kozik M. , Kozik A.

Acta Biochimica Polonica

|

2016

|

tom 63

|

nr 3

427-436

EN

Candida tropicalis is one of the most frequent causes of serious disseminated candidiasis in human patients infected by non-albicans Candida species, but still relatively little is known about its virulence mechanisms. In our current study, the interactions between the cell surface of this species and a multifunctional human protein - high-molecular-mass kininogen (HK), an important component of the plasma contact system involved in the development of the inflammatory state - were characterized at the molecular level. The quick release of biologically active kinins from candidal cell wall-adsorbed HK was presented and the HK-binding ability was assigned to several cell wall-associated proteins. The predicted hyphally regulated cell wall protein (Hyr) and some housekeeping enzymes exposed at the cell surface (known as "moonlighting proteins") were found to be the major HK binders. Accordingly, after purification of selected proteins, the dissociation constants of the complexes of HK with Hyr, enolase, and phosphoglycerate mutase were determined using surface plasmon resonance measurements, yielding the values of 2.20 × 10-7 M, 1.42 × 10-7 M, and 5.81 × 10-7 M, respectively. Therefore, in this work, for the first time, the interactions between C. tropicalis cell wall proteins and HK were characterized in molecular terms. Our findings may be useful for designing more effective prevention and treatment approaches against infections caused by this dangerous fungal pathogen.

18

Inactivation of α1-proteinase inhibitor by Candida albicans aspartic proteases favors the epithelial and endothelial cell colonization in the presence of neutrophil extracellular traps

51%

Gogol M. , Ostrowska D. , Klaga K. , Bochenska O. , Wolak N. , Aoki W. , Ueda M. , Kozik A. , Rapala-Kozik M.

Acta Biochimica Polonica

|

2016

|

tom 63

|

nr 1

167-175

EN

Candida albicans, a causative agent of opportunistic fungal infections in immunocompromised patients, uses ten secreted aspartic proteases (SAPs) to deregulate the homeostasis of the host organism on many levels. One of these deregulation mechanisms involves a SAP-dependent disturbance of the control over proteolytic enzymes of the host by a system of dedicated proteinase inhibitors, with one important example being the neutrophil elastase and alpha1-proteinase inhibitor (A1PI). In this study, we found that soluble SAPs 1-4 and the cell membrane-anchored SAP9 efficiently cleaved A1PI, with the major cleavage points located at the C-terminal part of A1PI in a close vicinity to the reactive-site loop that plays a critical role in the inhibition mechanism. Elastase is released by neutrophils to the environment during fungal infection through two major processes, a degranulation or formation of neutrophil extracellular traps (NET). Both, free and NET-embedded elastase forms, were found to be controlled by A1PI. A local acidosis, resulting from the neutrophil activity at the infection sites, favors A1PI degradation by SAPs. The deregulation of NET-connected elastase affected a NET-dependent damage of epithelial and endothelial cells, resulting in the increased susceptibility of these host cells to candidal colonization. Moreover, the SAP-catalyzed cleavage of A1PI was found to decrease its binding affinity to a proinflammatory cytokine, interleukin-8. The findings presented here suggest a novel strategy used by C. albicans for the colonization of host tissues and overcoming the host defense.