JNK pathway and heat shock response mediate the survival of C26 colon carcinoma bearing mice fed with the mushroom Pleurotus eryngii var. eryngii without affecting tumor growth or cachexia.

In the last few years, there has been emerging interest in developing treatments against human diseases using natural bioactive content. Here, the powder of the edible mushroom Pleurotus eryngii var. eryngii was mixed with the normal diet of mice bearing C26 colon carcinoma. Interestingly, it was evidenced by a significant increase in the survival rate of C26 tumor-bearing mice accompanied by a significant increase in Hsp90 and Hsp27 protein levels in the tumors. These data were paralleled by a decrease in Hsp60 levels. The mushroom introduced in the diet induced the inhibition of the transcription of the pro-inflammatory cytokines IL-6 and IL-1 exerting an anti-inflammatory action. The effects of the mushroom were mediated by the activation of c-Jun NH2-terminal kinases as a result of metabolic stress induced by the micronutrients introduced in the diet. In the tumors of C26 bearing mice fed with Pleurotus eryngii there was also a decreased expression of the mitotic regulator survivin and the anti-apoptotic factor Bcl-xL as well as an increase in the expression levels of Atg7, a protein that drives autophagy. In our hypothesis the interplay of these molecules favored the survival of the mice fed with the mushroom. These data are promising for the introduction of Pleurotus eryngii as a dietary supplement or as an adjuvant in anti-cancer therapy.

Chicoric acid binds to two sites and decreases the activity of the YopH bacterial virulence factor.

Chicoric acid (CA) is a phenolic compound present in dietary supplements with a large spectrum of biological properties reported ranging from antioxidant, to antiviral, to immunostimulatory properties. Due to the fact that chicoric acid promotes phagocytic activity and was reported as an allosteric inhibitor of the PTP1B phosphatase, we examined the effect of CA on YopH phosphatase from pathogenic bacteria, which block phagocytic processes of a host cell. We performed computational studies of chicoric acid binding to YopH as well as validation experiments with recombinant enzymes. In addition, we performed similar studies for caffeic and chlorogenic acids to compare the results. Docking experiments demonstrated that, from the tested compounds, only CA binds to both catalytic and secondary binding sites of YopH. Our experimental results showed that CA reduces activity of recombinant YopH phosphatase from Yersinia enterocolitica and human CD45 phosphatase. The inhibition caused by CA was irreversible and did not induce oxidation of catalytic cysteine. We proposed that inactivation of YopH induced by CA is involved with allosteric inhibition by interacting with essential regions responsible for ligand binding.

A Proposed Molecular Mechanism of High-Dose Vitamin D3 Supplementation in Prevention and Treatment of Preeclampsia.

A randomized prospective clinical study performed on a group of 74 pregnant women (43 presenting with severe preeclampsia) proved that urinary levels of 15-F(2t)-isoprostane were significantly higher in preeclamptic patients relative to the control (3.05 vs. 2.00 ng/mg creatinine). Surprisingly enough, plasma levels of 25-hydroxyvitamin D3 in both study groups were below the clinical reference range with no significant difference between the groups. In vitro study performed on isolated placental mitochondria and placental cell line showed that suicidal self-oxidation of cytochrome P450scc may lead to structural disintegration of heme, potentially contributing to enhancement of oxidative stress phenomena in the course of preeclampsia. As placental cytochrome P450scc pleiotropic activity is implicated in the metabolism of free radical mediated arachidonic acid derivatives as well as multiple Vitamin D3 hydroxylations and progesterone synthesis, we propose that Vitamin D3 might act as a competitive inhibitor of placental cytochrome P450scc preventing the production of lipid peroxides or excess progesterone synthesis, both of which may contribute to the etiopathogenesis of preeclampsia. The proposed molecular mechanism is in accord with the preliminary clinical observations on the surprisingly high efficacy of high-dose Vitamin D3 supplementation in prevention and treatment of preeclampsia.

Protein tyrosine phosphatase CD45 as a molecular biosensor of hydrogen peroxide generation in cell culture media.

We have designed a useful method of assessing reactive oxygen species generation in biological fluids. The novel assay utilizes tyrosine phosphatase CD45 as a biosensor of oxidative stress. Applying this new method, we examined oxygen species generation in the following cell culture media: RPMI 1640, DMEM, DMEM enriched with pyruvate and MEM. We discovered that the media (especially RPMI 1640) significantly reduced the activity of protein tyrosine phosphatase. The media-caused inactivation of CD45 was reversible after treatment with dithiothreitol being a powerful reducing agent. Interestingly, the media supplemented with catalase did not exhibit any inhibitory effect on CD45 activity which suggests a hydrogen peroxide-mediated mechanism of the enzyme inactivation. In addition to that, we assessed the impact of oxidative stress level on the activity of CD45 as measured in Jurkat cells cultured in RPMI 1640 either exposed or not exposed to the light of laminar flow cabinet fluorescent lamp. We found that Jurkat cells that were exposed to light displayed ca. 20% lower activity of CD45 than the cells protected against the light. The obtained results indicate that production of hydrogen peroxide in the medium leading to inhibition of CD45 was light-dependent, and that careful protection of cell culture media from the light may help to prevent the artifact in cell studies. Hydrogen peroxide, responsible for CD45 inactivation, can be generated in cell culture media after exposition to light due to photoreactive amino acids present in the media.