Adam Wilczok

Model neuromelanins as antioxidative agents during lipid peroxidation

The oxidative pathway of dopamine metabolism in the human brain leads to formation and accumulation of neuromelanin in the cytoplasm of most nigrostriatal dopaminergic neurons. The physiological significance of neuromelanin and its contribution to the neurodegenerative processes underlying Parkinson’s disease are still controversial.The effect of model neuromelanins on Fe(II)/ascorbate-induced lipid peroxidation in micelles of linoleic acid and in lecithin liposomes was determined. Synthetic neuromelanins were obtained from dopamine (DA), 5-S-cysteinyldopamine (CysDA) or from equimolar mixture of these precursors. Thiobarbituric acid test and reverse-phase HPLC, used for measurements of primary and secondary oxidation products, showed that all melanins tested significantly suppressed peroxidation of both, linoleic acid and liposomal lecithin. The inhibitory effect of CysDA-melanin was lower than of DA/CysDA-melanin and DA-melanin. All the melanins were able to reduce linoleic acid hydroperoxides to their stable hydroxy derivatives. The results obtained suggest that neuromelanin can act as natural antioxidant. The fatty acid hydroperoxide-reducing ability demonstrated for the model neuromelanins appears to be involved in the mechanism of antioxidative activity of neuromelanin.

Dopamine-melanin protects against tyrosine nitration, tryptophan oxidation and Ca2+-ATPase inactivation induced by peroxynitrite

The effects of dopamine-melanin (DA-melanin), a synthetic model of neuromelanin, on peroxynitrite-mediated 3-nitrotyrosine formation, oxidation of tryptophan in bovine serum albumin and inactivation of erythrocyte membrane Ca(2+)-ATPase activity were investigated in the absence and in the presence of bicarbonate. DA-melanin inhibited nitration of free tyrosine, loss of tryptophan residues and Ca(2+)-ATPase inactivation by peroxynitrite in a dose dependent manner. In the presence of bicarbonate, this inhibitory effect was lower for nitration and insignificant for oxidative protein modifications. These results suggest that neuromelanin can protect against nitrating and oxidizing action of peroxynitrite but is a worse protector against the peroxynitrite-CO(2) adduct. As peroxynitrite may be a mediator of neurotoxic processes, the obtained results suggest that neuromelanin may be important as a physiological protector against peroxynitrite.

Rhodium(II) complexes with phenanthrolines and their metabolic action on synchronized cell culture

Abstract Dimeric rhodium(II) acetato (OAc), lactato, and mandelato (mand) complexes with phenanthrolines [Rh 2 (OOCR) 2 (NN) 2 (H 2 O](OOCR) 2 (R = CH 3 , CH 3 CHOH, C 6 H 5 CHOH, NN = 1,10-phenanthroline (phen) and 4,7-diphenyl-1,10-phenanthroline (dpp)) have been synthesized and characterized using electronic, IR, and NMR spectra. Cytostatic activity of these complexes against the synchronously cultivated green alga Chlorella vulgaris has been investigated. The obtained results indicate that cationic complexes [Rh 2 (RCOO) 2 (NN) 2 (H 2 O) 2 ] 2+ show higher cytostatic activity than [Rh 2 (OAc) 4 (H 2 O) 2 ].

Aldehydic lipid peroxidation products in human brain astrocytomas

Among mediators of oxidative stress, highly reactive secondary aldehydic lipid peroxidation products can initiate the processes of spontaneous mutagenesis and carcinogenesis and can also act as a growth-regulating factors and signaling molecules. We explored whether these aldehydes and histone H3 mRNA levels could serve as biomarkers of malignancy and predictive factor in human brain astrocytomas. Histone H3 mRNA, a biomarker of cellular proliferation, was analyzed by QRT-PCR (TaqMan). Aldehydic lipid peroxidation products were determined as their dinitrophenylhydrazone derivatives in specimens obtained from 26 adult patients with brain astrocytomas. RP-HPLC with diode array detector and MSMS spectrometer were used for the analysis. H3 mRNA, 2-hydroxyhexanal, and 4-hydroxynonenal levels were higher in high-grade astrocytomas compared to low-grade astrocytomas and showed negative correlation with survival. Higher levels of 2-hydroxyhexanal and 4-hydroxynonenal, and lower levels of n-hexanal were associated with poorer patient prognosis. Our data suggest that tissue concentrations of aldehydic lipid peroxidation products can assist grading and predicting the clinical outcome in patients with astrocytic brain tumors. Possibly, this parameter will enhance optimal selection of patients for individualized treatment protocols, tailored to unique biochemical and molecular profile of the tumor.

Toxic effects of n-3 polyunsaturated fatty acids in human lung A549 cells.

N-3 polyunsaturated fatty acids (PUFAs), particularly eicosapentaenoic acid (EPA, 20:5) and docosahexaenoic acid (DHA, 22:6) are crucial for the prevention of lung cancer. PUFAs may act through alteration of membrane fluidity and cell surface receptor functions; modulation of cyclooxygenase activity; and increased cellular oxidative stress, which may induce apoptosis and autophagy. Therefore the aim of the study was to investigate whether EPA and DHA (25-100 μM) are able to reduce human lung cancer cell growth through oxidative stress influence on autophagy and apoptosis. It was found that both EPA and DHA in the concentration-dependent manner suppressed the cell viability, enhanced cell death, induced activation of caspase-3/7 and potentiated intracellular oxidative DNA and protein damage. In response to PUFAs intracellular autophagic vacuolization occurred and the observed effect was reverted when the autophagy inhibitor 3-methyladenine (3-MA) was applied. The inhibition of the autophagic process enhanced the cell viability, suppressed cell death, and decreased activation of caspase-3/7 indicating that EPA and DHA-induced autophagy amplified A549 apoptotic cell death.

Phytic Acid Inhibits Lipid Peroxidation In Vitro

Phytic acid (PA) has been recognized as a potent antioxidant and inhibitor of iron-catalyzed hydroxyl radical formation under in vitro and in vivo conditions. Therefore, the aim of the present study was to investigate, with the use of HPLC/MS/MS, whether PA is capable of inhibiting linoleic acid autoxidation and Fe(II)/ascorbate-induced peroxidation, as well as Fe(II)/ascorbate-induced lipid peroxidation in human colonic epithelial cells. PA at 100 μM and 500 μM effectively inhibited the decay of linoleic acid, both in the absence and presence of Fe(II)/ascorbate. The observed inhibitory effect of PA on Fe(II)/ascorbate-induced lipid peroxidation was lower (10–20%) compared to that of autoxidation. PA did not change linoleic acid hydroperoxides concentration levels after 24 hours of Fe(II)/ascorbate-induced peroxidation. In the absence of Fe(II)/ascorbate, PA at 100 μM and 500 μM significantly suppressed decomposition of linoleic acid hydroperoxides. Moreover, PA at the tested nontoxic concentrations (100 μM and 500 μM) significantly decreased 4-hydroxyalkenal levels in Caco-2 cells which structurally and functionally resemble the small intestinal epithelium. It is concluded that PA inhibits linoleic acid oxidation and reduces the formation of 4-hydroxyalkenals. Acting as an antioxidant it may help to prevent intestinal diseases induced by oxygen radicals and lipid peroxidation products.

Preliminary study of the expression of genes connected with the orexigenic and anorexigenic system using microarray technique in anorexia nervosa.

The pathogenesis of anorexia nervosa (AN) is still poorly understood. The Diagnostic and Statistical Manual of Mental Disorders (4th edition) classification differentiates 2 AN types: the restricting type (AN-R) and the binge eating/purging type (AN-BP). We investigated 4 young women suffering from AN (2 with AN-R and 2 with AN-BP). Four women, age matched, with other psychiatric disorders (paranoid schizophrenia, adjustment disorder, mental retardation) served as the reference group. The oligonucleotide microarray method (HG-U133A, Affymetrix) was used to determine the expression profile of 13 genes connected with the orexigenic and anorexigenic system: leptin, leptin receptor-coding gene, hypocretin (orexin) receptor-coding gene, hypocretin (orexin) neuropeptide precursor-coding gene and growth hormone secretagogue receptor. A hierarchical analysis of the results showed that AN-BP and AN-R patients were grouped into different clusters. Also, expression levels of leptin receptor-coding gene showed significant differences between AN-BP and AN-R patients and between AN-R and control subjects. This preliminary study suggests that the microarray technique may contribute to elucidating molecular genetics of the pathogenesis of both types of AN.

Osteogenic differentiation of human mesenchymal stem cells from adipose tissue and Wharton’s jelly of the umbilical cord

Induced osteogenesis of mesenchymal stem cells (MSCs) may provide an important tool for bone injuries treatment. Human umbilical cord and adipose tissue are routinely discarded as clinical waste and may be used as noncontroversial MSCs sources. It still remains to be verified which source of MSCs is the most suitable for bone regeneration. The aim of this research was to investigate the osteogenic potential of human MSCs derived from adipose tissue (AT-MSCs) and Whartons jelly of the human umbilical cord (WJ-MSCs) differentiated under the same conditions. Osteogenic differentiation of MSCs was detected and quantified by alizarin red S (ARS) staining for calcium deposition and alkaline phosphatase (ALP) activity, osteoprotegerin (OPG), and osteocalcin (OC) secretion measurements. Under osteogenic conditions, after 21 days of differentiation, the measured ALP activity and calcium deposition were significantly higher in the AT-MSCs than in the WJ-MSCs, while the OPG and OC secretion were higher in the WJ-MSCs vs. AT-MSCs. Low concentrations of OPG and high levels of OC in AT-MSCs and WJ-MSCs, prove that these cells reached an advanced stage of the osteogenic differentiation. The levels of OC secreted by AT-MSCs were lower than by WJ-MSCs. Both cell types, AT-MSCs and WJ-MSCs possess a potential to differentiate towards the osteogenic lineage. The observed differences in the levels of osteogenic markers suggest that after 21-days of osteogenic differentiation, the AT-MSCs might have reached a more advanced stage of differentiation than WJ-MSCs.

Changes in expression of cartilaginous genes during chondrogenesis of Wharton's jelly mesenchymal stem cells on three-dimensional biodegradable poly(L-lactide-co-glycolide) scaffolds

BackgroundIn cartilage tissue regeneration, it is important to develop biodegradable scaffolds that provide a structural and logistic template for three-dimensional cultures of chondrocytes. In this study, we evaluated changes in expression of cartilaginous genes during in vitro chondrogenic differentiation of WJ-MSCs on PLGA scaffolds.MethodsThe biocompatibility of the PLGA material was investigated using WJ-MSCs by direct and indirect contact methods according to the ISO 10993–5 standard. PLGA scaffolds were fabricated by the solvent casting/salt-leaching technique. We analyzed expression of chondrogenic genes of WJ-MSCs after a 21-day culture.ResultsThe results showed the biocompatibility of PLGA and confirmed the usefulness of PLGA as material for fabrication of 3D scaffolds that can be applied for WJ-MSC culture. The in vitro penetration and colonization of the scaffolds by WJ-MSCs were assessed by confocal microscopy. The increase in cell number demonstrated that scaffolds made of PLGA copolymers enabled WJ-MSC proliferation. The obtained data showed that as a result of chondrogenesis of WJ-MSCs on the PLGA scaffold the expression of the key markers collagen type II and aggrecan was increased.ConclusionsThe observed changes in transcriptional activity of cartilaginous genes suggest that the PLGA scaffolds may be applied for WJ-MSC differentiation. This primary study suggests that chondrogenic capacity of WJ-MSCs cultured on the PLGA scaffolds can be useful for cell therapy of cartilage.

DHA but not AA Enhances Cisplatin Cytotoxicity in Ovarian Cancer Cells

Abstract Clinical and epidemiological studies show that docosahexaenoic acid (DHA) and arachidonic acid (AA) exert multiple effects on ovarian cancer. While DHA seems to inhibit growth and prevent carcinogenic processes, stimulation of leukotriene B4 receptors BLT1 and BLT2 by several eicosanoids derived from AA plays an important role in mediating cisplatin resistance in ovarian cancer cells. We examined whether DHA and AA exerted antiproliferative effect on epithelial ovarian cancer cells and whether these polyunsaturated fatty acids could alter their susceptibility to cisplatin. Using SKOV3 and OVCAR3 cell lines, we found that DHA but not AA suppressed the cells viability, proliferation, enhanced cell death, and induced activation of caspase-3/7 in the concentration- and time-dependent manner. The OVCAR3 cells were less susceptible to cisplatin than SKOV3 cells. DHA but not AA significantly potentiated cisplatin cytotoxicity in SKOV3 and OVCAR3 cells. We did not observe any significant influence of AA on the above mentioned processes in both cell lines. Similar effect can occur in ovarian cancer patients treated with cisplatin and supplemented with DHA.