Chemopreventive and renal protective effects for docosahexaenoic acid (DHA): implications of CRP and lipid peroxides

Background

The fish oil-derived ω-3 fatty acids, like docosahexanoic (DHA), claim a plethora of health benefits. We currently evaluated the antitumor effects of DHA, alone or in combination with cisplatin (CP) in the EAC solid tumor mice model, and monitored concomitant changes in serum levels of C-reactive protein (CRP), lipid peroxidation (measured as malondialdehyde; MDA) and leukocytic count (LC). Further, we verified the capacity of DHA to ameliorate the lethal, CP-induced nephrotoxicity in rats and the molecular mechanisms involved therein.

Results

EAC-bearing mice exhibited markedly elevated LC (2-fold), CRP (11-fold) and MDA levels (2.7-fold). DHA (125, 250 mg/kg) elicited significant, dose-dependent reductions in tumor size (38%, 79%; respectively), as well as in LC, CRP and MDA levels. These effects for CP were appreciably lower than those of DHA (250 mg/kg). Interestingly, DHA (125 mg/kg) markedly enhanced the chemopreventive effects of CP and boosted its ability to reduce serum CRP and MDA levels. Correlation studies revealed a high degree of positive association between tumor growth and each of CRP (r = 0.85) and leukocytosis (r = 0.89), thus attesting to a diagnostic/prognostic role for CRP. On the other hand, a single CP dose (10 mg/kg) induced nephrotoxicity in rats that was evidenced by proteinuria, deterioration of glomerular filtration rate (GFR, -4-fold), a rise in serum creatinine/urea levels (2–5-fold) after 4 days, and globally-induced animal fatalities after 7 days. Kidney-homogenates from CP-treated rats displayed significantly elevated MDA- and TNF-α-, but reduced GSH-, levels. Rats treated with DHA (250 mg/kg, but not 125 mg/kg) survived the lethal effects of CP, and showed a significant recovery of GFR; while their homogenates had markedly-reduced MDA- and TNF-α-, but -increased GSH-levels. Significant association was detected between creatinine level and those of MDA (r = 0.81), TNF-α ) r = 0.92) and GSH (r = -0.82); implying causal relationships.

Conclusion

DHA elicited prominent chemopreventive effects on its own, and appreciably augmented those of CP as well. The extent of tumor progression in various mouse groups was highly reflected by CRP levels (thus implying a diagnostic/prognostic role for CRP). Further, this study is the first to reveal that DHA can obliterate the lethal CP-induced nephrotoxicity and renal tissue injury. At the molecular level, DHA appears to act by reducing leukocytosis, systemic inflammation, and oxidative stress.     

Chitotriosidase - a putative biomarker for sporadic amyotrophic lateral sclerosis

Background

Potential biomarkers to aid diagnosis and therapy need to be identified for Amyotrophic Lateral Sclerosis, a progressive motor neuronal degenerative disorder. The present study was designed to identify the factor(s) which are differentially expressed in the cerebrospinal fluid (CSF) of patients with sporadic amyotrophic lateral sclerosis (SALS; ALS-CSF), and could be associated with the pathogenesis of this disease.

Results

Quantitative mass spectrometry of ALS-CSF and control-CSF (from orthopaedic surgical patients undergoing spinal anaesthesia) samples showed upregulation of 31 proteins in the ALS-CSF, amongst which a ten-fold increase in the levels of chitotriosidase-1 (CHIT-1) was seen compared to the controls. A seventeen-fold increase in the CHIT-1 levels was detected by ELISA, while a ten-fold elevated enzyme activity was also observed. Both these results confirmed the finding of LC-MS/MS. CHIT-1 was found to be expressed by the Iba-1 immunopositive microglia.

Conclusion

Elevated CHIT-1 levels in the ALS-CSF suggest a definitive role for the enzyme in the disease pathogenesis. Its synthesis and release from microglia into the CSF may be an aligned event of neurodegeneration. Thus, high levels of CHIT-1 signify enhanced microglial activity which may exacerbate the process of neurodegeneration. In view of the multifold increase observed in ALS-CSF, it can serve as a potential CSF biomarker for the diagnosis of SALS.     

Studies of esterase 6 in Drosophila melanogaster. XVIII. Biochemical differences between the slow and fast allozymes

Most natural populations of Drosophila melanogaster are polymorphic for two major electrophoretic variants at the esterase-6 locus. The frequency of the EST 6F allozyme is greatest in populations in warmer latitudes, whereas the EST 6S allozyme is predominant in colder latitudes. Latitudinal clines in electromorph frequencies are found on three continents. Purified preparations of the allozymes have been characterized for their pH optimum, substrate specificity, organophosphate inhibition, alcohol activation, thermal stability, and kinetic parameters. These and previous analyses of the EST 6 allozymes reveal that the two variants have differences in their physical and kinetic properties that may provide a basis for the selective maintenance of the polymorphisms and an explanation of the clinal variation observed in natural populations.      

Spermatogonial stem cell sensitivity to capsaicin: An in vitro study

Background

The placenta is an important site for iron metabolism in humans. It transfers iron from the mother to the fetus. One of the major iron transport proteins is transferrin, which is a blood plasma protein crucial for iron uptake. Its localization and expression may be one of the markers to distinguish placental dysfunction.

Methods

In the experimental study we used antibody preparation, mass spectrometric analysis, biochemical and immunocytochemical methods for characterization of transferrin expression on the human choriocarcinoma cell line JAR (JAR cells), placental lysates, and cryostat sections. Newly designed monoclonal antibody TRO-tf-01 to human transferrin was applied on human placentae from normal (n = 3) and abnormal (n = 9) pregnancies.

Results

Variations of transferrin expression were detected in villous syncytiotrophoblast, which is in direct contact with maternal blood. In placentae from normal pregnancies, the expression of transferrin in the syncytium was significantly lower (p < 0.001) when compared to placentae from abnormal ones (gestational diabetes, pregnancy induced hypertension, drug abuse).

Conclusion

These observations suggest that in the case of abnormal pregnancies, the fetus may require higher levels of transferrin in order to prevent iron depletion due to the stress from the placental dysfunction.     

Filamentous brown algae infected by the marine,holocarpic oomycete Eurychasma dicksonii: first results on the organization and the role of cytoskeleton in both host and parasite

The important role of the cytoskeletal scaffold is increasingly recognized in host-pathogen interactions. The cytoskeleton potentially functions as a weapon for both the plants defending themselves against fungal or oomycete parasites, and for the pathogens trying to overcome the resisting barrier of the plants. This concept, however, had not been investigated in marine algae so far. We are opening this scientific chapter with our study on the functional implications of the cytoskeleton in 3 filamentous brown algal species infected by the marine oomycete Eurychasma dicksonii. Our observations suggest that the cytoskeleton is involved in host defense responses and in fundamental developmental stages of E. dicksonii in its algal host.Oomycetes are important plant and animal pathogens and are the cause of significant crop losses every year. Hence, a plethora of studies with different cultivated and model plant species investigate the diversity of parasite infection pathways and host defense responses.¹ However, little information is available on the interactions between algae and marine oomycetes, despite the epidemic outbreaks reported² and the huge impact on intensive algal aquaculture.³Eurychasma dicksonii is a biotrophic, intracellular marine oomycete, capable to infect at least 45 species of brown seaweeds in laboratory cultures.⁴ Molecular data reveal that E. dicksonii has a basal phylogenetic position in the oomycete lineage.^5,6 The basic stages of the infection are known: the attachment of the parasite spore to the host cell wall, the penetration of its cytoplasm into the host cell, the formation of a multinucleated, unwalled thallus, and zoosporogenesis.⁶ Hitherto, though, there was no knowledge about the role of cytoskeleton in the context of infection, which stimulated our research.In land plants, reorganization of the cytoskeleton is part of the reaction to infection by fungal pathogens. The rearrangement of the cytoplasm and the relocation of the nuclei and other organelles are accompanied by rapid rearrangements of the cytoskeletal elements.⁷ The plant cytoskeleton shows an extreme plasticity in order to serve the intracellular realignment.At the same time, this indicates that the plant cytoskeleton could be the parasite’s target by producing anti-cytoskeletal compounds in an effort to overcome plant resistance, a mechanism known in several fungal and oomycete pathogens of higher plants.^8,9Consequently, the changes in microtubule (MT) organization are associated with both the plant defense and/or susceptibility toward oomycetes, respectively.¹⁰ Therefore, our research on the organization and role of cytoskeleton in the host and the parasite sheds some light into the enormous variability in the specificity of the recognition, defense, and infection mechanisms.     

A whole genome screen for HIV restriction factors

Background

Human T-cell leukemia virus type 1 (HTLV-1) causes adult T-cell leukemia (ATL) and HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP) in a small percentage of infected individuals. ATL is often associated with general immune suppression and an impaired HTLV-1-specific T-cell response, an important host defense system. We previously found that a small fraction of asymptomatic HTLV-1-carriers (AC) already showed impaired T-cell responses against the major target antigen, Tax. However, it is unclear whether the impaired HTLV-1 Tax-specific T-cell response in these individuals is an HTLV-1-specific phenomenon, or merely reflects general immune suppression. In this study, in order to characterize the impaired HTLV-1-specific T-cell response, we investigated the function of Tax-specific CD8⁺ T-cells in various clinical status of HTLV-1 infection.

Results

By using tetramers consisting of HLA-A*0201, -A*2402, or -A*1101, and corresponding Tax epitope peptides, we detected Tax-specific CD8⁺ T-cells in the peripheral blood from 87.0% of ACs (n = 20/23) and 100% of HAM/TSP patients (n = 18/18) tested. We also detected Tax-specific CD8⁺ T-cells in 38.1% of chronic type ATL (cATL) patients (n = 8/21), although its frequencies in peripheral blood CD8⁺ T cells were significantly lower than those of ACs or HAM/TSP patients. Tax-specific CD8⁺ T-cells detected in HAM/TSP patients proliferated well in culture and produced IFN-γ when stimulated with Tax peptides. However, such functions were severely impaired in the Tax-specific CD8⁺ T-cells detected in cATL patients. In ACs, the responses of Tax-specific CD8⁺ T-cells were retained in most cases. However, we found one AC sample whose Tax-specific CD8⁺ T-cells hardly produced IFN-γ, and failed to proliferate and express activation (CD69) and degranulation (CD107a) markers in response to Tax peptide. Importantly, the same AC sample contained cytomegalovirus (CMV) pp65-specific CD8⁺ T-cells that possessed functions upon CMV pp65 peptide stimulation. We further examined additional samples of two smoldering type ATL patients and found that they also showed dysfunctions of Tax-specific but not CMV-specific CD8⁺ T-cells.

Conclusions

These findings indicated that Tax-specific CD8⁺ T-cells were scarce and dysfunctional not only in ATL patients but also in a limited AC population, and that the dysfunction was selective for HTLV-1-specifc CD8⁺ T-cells in early stages.