Cellular Protector Research Articles

Hydrogen peroxide fluorescent probe-monitored butyric acid inhibition of the ferroptosis process.

Short-chain fatty acids, such as butyrate, play pivotal roles in various physiological processes within the human body. Recent advances in understanding cell death pathways, specifically ferroptosis, have unveiled unique opportunities for therapeutic development. Ferroptosis is linked to iron accumulation and oxidative stress, whereas butyrate has emerged as a cellular protector against oxidative stress, potentially inhibiting ferroptosis. Hydrogen peroxide (H2 O2 ) is a key player in oxidative stress, and its monitoring has gained significance in disease mechanisms. We present an innovative fluorescent probe, HOP, capable of dynamically tracking intracellular H2 O2 levels, enabling spatial and temporal visualization. The probe exhibits high accuracy (limit of detection = 0.14 μM) and sensitivity, paving the way for disease diagnosis and treatment innovations. Importantly, HOP displayed minimal toxicity, making it suitable for cellular applications. Cellular imaging experiments demonstrated its ability to penetrate cells and monitor intracellular H2 O2 levels accurately. The HOP probe confirmed H2 O2 as a critical marker in ferroptosis. Our innovative HOP provides a powerful tool for tracking intracellular H2 O2 levels and offers insights into the modulation of ferroptosis, potentially opening new avenues for disease research and therapeutic interventions.

The Roles of NFR2-Regulated Oxidative Stress and Mitochondrial Quality Control in Chronic Liver Diseases.

Chronic liver disease (CLD) affects a significant portion of the global population, leading to a substantial number of deaths each year. Distinct forms like non-alcoholic fatty liver disease (NAFLD) and alcoholic fatty liver disease (ALD), though they have different etiologies, highlight shared pathologies rooted in oxidative stress. Central to liver metabolism, mitochondria are essential for ATP production, gluconeogenesis, fatty acid oxidation, and heme synthesis. However, in diseases like NAFLD, ALD, and liver fibrosis, mitochondrial function is compromised by inflammatory cytokines, hepatotoxins, and metabolic irregularities. This dysfunction, especially electron leakage, exacerbates the production of reactive oxygen species (ROS), augmenting liver damage. Amidst this, nuclear factor erythroid 2-related factor 2 (NRF2) emerges as a cellular protector. It not only counters oxidative stress by regulating antioxidant genes but also maintains mitochondrial health by overseeing autophagy and biogenesis. The synergy between NRF2 modulation and mitochondrial function introduces new therapeutic potentials for CLD, focusing on preserving mitochondrial integrity against oxidative threats. This review delves into the intricate role of oxidative stress in CLD, shedding light on innovative strategies for its prevention and treatment, especially through the modulation of the NRF2 and mitochondrial pathways.

Insights of microalgal municipal wastewater treatment at low temperatures: Performance, microbiota patterns, and cold-adaptation of tubular and aeration column photobioreactors

In order to refine the treatment of microalgae consortium (MC) for municipal wastewater (MWW) during the winter, this study investigated the effectiveness of tubular and aeration column photobioreactors (TPBR and APBR) in wastewater treatment plant (WWTP) during winter by two start-up modes: microalgae/microalgae-activated sludge (AS). The operation results showed that under 5.7–13.1 °C, TPBR enhanced the assimilation of N and P pollutant by microalgal accumulation, meeting the Chinese discharge standard within 24 h (NH4+-N, TP, and COD ≤8.0, 0.5, and 50 mg·L−1). The microbial community profiles were identified and showed that inoculating AS under low-temperature still promoted bacterial interspecific association, but influenced by the inhibition of microbial diversity by the homogeneous circulation of TPBR, the nitrogen transfer function of MC was lower than that of APBR at low temperatures, except nitrogen fixation (K02588), nitrosification (K10944, K10945, and K10946), assimilatory nitrate reduction (K00366), and ammonification (K01915 and K05601). And the intermittent aeration in the APBR was still beneficial in increasing microbial diversity, which was more beneficial for reducing COD through microbial collaboration. In the treatment, the cryotolerant MGPM were Delftia, Romboutsia, Rhizobiales, and Bacillus, and the cold stress-related genes that were highly up-regulated were defense signaling molecules (K03671 and K00384), cold shock protein gene (K03704), and cellular protector (K01784) were present in both PBRs. This study provided a reference for the feasibility of the low temperature treatment of MC with the different types of PBR, which improved the application of wastewater treatment in more climatic environments.

Stapled Peptides as Direct Inhibitors of Nrf2-sMAF Transcription Factors.

Nuclear factor erythroid-related 2-factor 2 (Nrf2) is a transcription factor traditionally thought of as a cellular protector. However, in many cancers, Nrf2 is constitutively activated and correlated with therapeutic resistance. Nrf2 heterodimerizes with small musculoaponeurotic fibrosarcoma Maf (sMAF) transcription factors, allowing binding to the antioxidant responsive element (ARE) and induction of transcription of Nrf2 target genes. While transcription factors are historically challenging to target, stapled peptides have shown great promise for inhibiting these protein-protein interactions. Herein, we describe the first direct cell-permeable inhibitor of Nrf2/sMAF heterodimerization. N1S is a stapled peptide designed based on AlphaFold predictions of the interactions between Nrf2 and sMAF MafG. A cell-based reporter assay combined with in vitro biophysical assays demonstrates that N1S directly inhibits Nrf2/MafG heterodimerization. N1S treatment decreases the transcription of Nrf2-dependent genes and sensitizes Nrf2-dependent cancer cells to cisplatin. Overall, N1S is a promising lead for the sensitization of Nrf2-addicted cancers.

NRF2 signaling pathway: A comprehensive prognostic and gene expression profile analysis in breast cancer.

Breast cancer is the most frequently diagnosed malignant tumor in women and a major public health concern. NRF2 axis is a cellular protector signaling pathway protecting both normal and cancer cells from oxidative damage. NRF2 is a transcription factor that binds to the gene promoters containing antioxidant response element-like sequences. In this report, differential expression of NRF2 signaling pathway elements, as well as the correlation of NRF2 pathway mRNAs with various clinicopathologic characteristics, including molecular subtypes, tumor grade, tumor stage, and methylation status, has been investigated in breast cancer using METABRIC and TCGA datasets. In the current report, our findings revealed the deregulation of several NRF2 signaling elements in breast cancer patients. Moreover, there were negative correlations between the methylation of NRF2 genes and mRNA expression. The expression of NRF2 genes significantly varied between different breast cancer subtypes. In conclusion, substantial deregulation of NRF2 signaling components suggests an important role of these genes in breast cancer. Because of the clear associations between mRNA expression and methylation status, DNA methylation could be one of the mechanisms that regulate the NRF2 pathway in breast cancer. Differential expression of Hippo genes among various breast cancer molecular subtypes suggests that NRF2 signaling may function differently in different subtypes of breast cancer. Our data also highlights an interesting link between NRF2 components' transcription and tumor grade/stage in breast cancer.

Kazinol C from Broussonetia kazinoki stimulates autophagy via endoplasmic reticulum stress-mediated signaling

ABSTRACT Autophagy modulators are considered putative therapeutic targets because of the role of autophagy in cancer progression. Kazinol C, a 1,3-diphenylpropane from the plant Broussonetia kazinoki, has been shown to induce apoptosis in colon cancer cells through the activation of AMPK at high concentrations. In the present study, we found that Kazinol C induced autophagy through endoplasmic reticulum stress-mediated unfolded protein response signaling in several normal and cancer cell lines at low concentrations of Kazinol C that did not induce apoptosis. Kazinol C activated the transducers of unfolded protein response signaling, leading to target gene expression, LC3-II conversion, and TFEB nuclear translocation. Chemical inhibition of endoplasmic reticulum stress reduced LC3-II conversion. In addition, blockade of autophagy by knockout of Atg5 or treatment with 3-MA enhanced Kazinol C-induced apoptosis. In summary, we have uncovered Kazinol C as a novel autophagy inducer and confirmed the role of autophagy as a cellular stress protector.

Ferroptosis and NRF2: an emerging battlefield in the neurodegeneration of Alzheimer's disease.

Ferroptosis is an iron- and lipid peroxidation-dependent cell death modality and emerging evidence indicates that ferroptosis has great explanatory potential for neuronal loss and associated CNS dysfunction in a range of neurodegenerative diseases (e.g., Alzheimer's, Parkinson's and Huntington's diseases, Motor neuron disease, Friedreich ataxia (FRDA)). Ferroptotic death results from lethal levels of phospholipid hydroperoxides that are generated by iron-dependent peroxidation of polyunsaturated fatty acids (PUFAs), such as arachidonic and adrenic acids, which are conjugated to specific phospholipids (e.g., phosphatidylethanolamines (PEs)). The major cellular protector against ferroptosis is glutathione peroxidase 4 (GPX4), a membrane-associated selenoenzyme that reduces deleterious phospholipid hydroperoxides to their corresponding benign phospholipid alcohols in a glutathione-dependent manner. Other complementary protective systems have also been identified that act to bolster cellular defences against ferroptosis. Many pharmacological modulators of the ferroptosis pathway have been identified, targeting proteins involved in iron homoeostasis and autophagy; the production and detoxification of lipid peroxides, and cyst(e)ine/glutathione metabolism. While a growing number of cell signalling pathways converge to regulate the ferroptosis cascade, an emerging understanding of ferroptosis regulation suggests that the ferroptotic 'tone' of cells can be set by the transcription factor, nuclear factor erythroid 2-related factor 2 (NRF2), which transcriptionally controls many key components of the ferroptosis pathway. In this review, we provide a critical overview of the relationship between ferroptosis and NRF2 signalling. With a focus on the role of ferroptosis in Alzheimer's disease (AD), we discuss how therapeutic modulation of the NRF2 pathway is a viable strategy to explore in the treatment of ferroptosis-driven neurodegeneration.

The Role of Nrf2 Activity in Cancer Development and Progression.

Nrf2 is a transcription factor that stimulates the expression of genes which have antioxidant response element-like sequences in their promoter. Nrf2 is a cellular protector, and this principle applies to both normal cells and malignant cells. While healthy cells are protected from DNA damage induced by reactive oxygen species, malignant cells are defended against chemo- or radiotherapy. Through our literature search, we found that Nrf2 activates several oncogenes unrelated to the antioxidant activity, such as Matrix metallopeptidase 9 (MMP-9), B-cell lymphoma 2 (BCL-2), B-cell lymphoma-extra large (BCL-xL), Tumour Necrosis Factor α (TNF-α), and Vascular endothelial growth factor A (VEGF-A). We also did a brief analysis of The Cancer Genome Atlas (TCGA) data of lung adenocarcinoma concerning the effects of radiation therapy and found that the therapy-induced Nrf2 activation is not universal. For instance, in the case of recurrent disease and radiotherapy, we observed that, for the majority of Nrf2-targeted genes, there is no change in expression level. This proves that the universal, axiomatic rationale that Nrf2 is activated as a response to chemo- and radiation therapy is wrong, and that each scenario should be carefully evaluated with the help of Nrf2-targeted genes. Moreover, there were nine genes involved in lipid peroxidation, which showed underexpression in the case of new radiation therapy: ADH1A, ALDH3A1, ALDH3A2, ADH1B, GPX2, ADH1C, ALDH6A1, AKR1C3, and NQO1. This may relate to the fact that, while some studies reported the co-activation of Nrf2 and other oncogenic signaling pathways such as Phosphoinositide 3-kinases (PI3K), mitogen-activated protein kinase (MAPK), and Notch1, other reported the inverse correlation between Nrf2 and the tumor-promoter Transcription Factor (TF), Nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB). Lastly, Nrf2 establishes its activity through interactions at multiple levels with various microRNAs. MiR-155, miR-144, miR-28, miR-365-1, miR-93, miR-153, miR-27a, miR-142, miR-29-b1, miR-340, and miR-34a, either through direct repression of Nrf2 messenger RNA (mRNA) in a Kelch-like ECH-associated protein 1 (Keap1)-independent manner or by enhancing the Keap1 cellular level, inhibit the Nrf2 activity. Keap1–Nrf2 interaction leads to the repression of miR-181c, which is involved in the Nuclear factor kappa light chain enhancer of activated B cells (NF-κB) signaling pathway. Nrf2’s role in cancer prevention, diagnosis, prognosis, and therapy is still in its infancy, and the future strategic planning of Nrf2-based oncological approaches should also consider the complex interaction between Nrf2 and its various activators and inhibitors.

Onion skin extract as a protective agent against oxidative stress in Saccharomyces cerevisiae induced by cadmium.

Onion skin extract is a source of bioactive compounds demonstrating a high antioxidant activity. The purpose of this research was to investigate the effect of onion skin extract at the level of oxidative stress markers in Saccharomyces cerevisiae exposed to cadmium. The generation of reactive oxygen species (ROS), antioxidant enzymes activity, total content of glutathione, and the level of lipid peroxidation in yeast cells were determined. Research showed that onion skin extract protected the yeast cells from the occurrence of oxidative stress induced by cadmium. Cells treated with onion skin extract and cadmium were characterized by lower generation of ROS, antioxidant enzymes activity, lipid peroxidation, and higher level of glutathione content than cells treated with cadmium only. However, the protective effect was dependent on the onion skin extract concentration in yeast medium. PRACTICAL APPLICATIONS: The presented studies are of comprehensive character regarding antioxidant properties of the onion skin extract, using Saccharomyces cerevisiae as a model organism. The research results give the opportunity to conduct further research on the use of onion skin extract in functional food or dietary supplements production, as a cellular protector against negative consequence of oxidative stress. It should also be mentioned that the major research material was onion skin which is a troublesome waste material for onion producers. Consequently, the study result will, to a certain extent provide an opportunity to increase interest in the problem of rational use of the waste material, according to a sustainable development idea.

PKR: A Kinase to Remember.

Aging is a major risk factor for many diseases including metabolic syndrome, cancer, inflammation, and neurodegeneration. Identifying mechanistic common denominators underlying the impact of aging is essential for our fundamental understanding of age-related diseases and the possibility to propose new ways to fight them. One can define aging biochemically as prolonged metabolic stress, the innate cellular and molecular programs responding to it, and the new stable or unstable state of equilibrium between the two. A candidate to play a role in the process is protein kinase R (PKR), first identified as a cellular protector against viral infection and today known as a major regulator of central cellular processes including mRNA translation, transcriptional control, regulation of apoptosis, and cell proliferation. Prolonged imbalance in PKR activation is both affected by biochemical and metabolic parameters and affects them in turn to create a feedforward loop. Here, we portray the central role of PKR in transferring metabolic information and regulating cellular function with a focus on cancer, inflammation, and brain function. Later, we integrate information from open data sources and discuss current knowledge and gaps in the literature about the signaling cascades upstream and downstream of PKR in different cell types and function. Finally, we summarize current major points and biological means to manipulate PKR expression and/or activation and propose PKR as a therapeutic target to shift age/metabolic-dependent undesired steady states.

Effect of metal in Schiff bases of chitosan adsorbed on glassy carbon electrode in the inhibition of sphingomyelinase C toxin

This study was conducted to assess the catalytic electrode surface adsorption and capture properties of different metal chitosan derivatives in aqueous phosphate buffer solution (pH = 7.3). Early, recent work showed that the response of Iron chitosan complex with R = -CH3 on the periphery, over blood red cells in presence of sphingomyelinase C was protected. The effect of others substituent (R = -Br, -Cl, -F, NO2, -OCH3, -H) on the periphery of the Schiff base ligand did not show correlation with the oxidation of sphingomyelinase C and its biological response. For this reason, various adsorbed metal (M = Fe of recent work, Cu, Ni and Co) complexes of chitosan and Schiff bases on glassy carbon electrode for the oxidation of sphingomyelinase C were investigated and compared, each one with -CH3 group on the periphery of the Schiff base. UV–Vis and IR-TF spectroscopies, electrochemistry and microscopy assay were performed; then, the metal effect underlying. For the Schiff base, cobalt and copper complexes did not proved to be a remarkable cellular protector in presence of the enzyme, but the nickel complex showed to be a cellular protector at short time, this conclusion help to proposal a reaction mechanism for the electrochemical and biological studies.

Cerebral insulin resistance: current concepts of the pathogenesis and possible therapeutic strategies

The review presents current concepts about the problem of cerebral insulin resistance (IR). It has now been established that cerebral IR plays a key role in the pathogenesis of degenerative and metabolic diseases of the brain. Based on literature data and own clinical experience, the authors recommend to use the standardized extract of ginkgo biloba EGb761 as a cellular protector, which increases insulin sensitivity of cells and reduces atherogenesis, in order to improve cognitive functions and quality of life in patients with diabetes mellitus.

Mechanistic characterization and inhibition of sphingomyelinase C over substituted Iron Schiff bases of chitosan adsorbed on glassy carbon electrode

The medical treatment of laxoscelisms is based solely on supportive measures. Although equine antiserum for Sphingomyelinase C (SMASE) and D isomers are available, it is not used due to the risk of an anaphylactic reaction and its unproven efficacy. As potential enzyme inhibitors, derivatives of Iron chitosan complexes were studied (Shiff base having –R = –H, –Cl, –Br, –F, –OCH3, –CH3, –NO2). These chitosan complexes were chosen because they have revealed good results in medicine and catalysis due to their biodegradable characteristics and bioavailability. Besides considering that these complexes have not been studied in relation to this toxin. The mechanisms underlying the catalytic and catcher effects of Iron chitosan complexes were studied using electrochemistry, UV–Vis spectroscopy and microscopic assay at physiological pH. The electrochemical studies showed that one of seven Schiff bases of chitosan adsorbed on glassy carbon electrode was electrocatalytically active for the oxidation of sphingomyelinase at 1.27 V, and that allowed proposing a reaction scheme for SMASE oxidation by adsorbed Iron complexes. On the other hand, even though the spectroscopic studies indicated that there was no chemical bond formation between the complex and SMASE in solution, the microscopic studies showed that this complex proved to be a remarkable cellular protector in presence of the enzyme. In conclusion, Shiff base of chitosan with R = –CH3 was the only active complex in front of sphingomyelinase C, protecting red blood cells, according to our electrochemical and microscopic studies.

Dehydroascorbic Acid Attenuates Ischemic Brain Edema and Neurotoxicity in Cerebral Ischemia: An in vivo Study.

Ischemic stroke results in the diverse phathophysiologies including blood brain barrier (BBB) disruption, brain edema, neuronal cell death, and synaptic loss in brain. Vitamin C has known as the potent anti-oxidant having multiple functions in various organs, as well as in brain. Dehydroascorbic acid (DHA) as the oxidized form of ascorbic acid (AA) acts as a cellular protector against oxidative stress and easily enters into the brain compared to AA. To determine the role of DHA on edema formation, neuronal cell death, and synaptic dysfunction following cerebral ischemia, we investigated the infarct size of ischemic brain tissue and measured the expression of aquaporin 1 (AQP-1) as the water channel protein. We also examined the expression of claudin 5 for confirming the BBB breakdown, and the expression of bcl 2 associated X protein (Bax), caspase-3, inducible nitric oxide synthase (iNOS) for checking the effect of DHA on the neurotoxicity. Finally, we examined postsynaptic density protein-95 (PSD-95) expression to confirm the effect of DHA on synaptic dysfunction following ischemic stroke. Based on our findings, we propose that DHA might alleviate the pathogenesis of ischemic brain injury by attenuating edema, neuronal loss, and by improving synaptic connection.

CysB-dependent upregulation of the Salmonella Typhimurium cysJIH operon in response to antimicrobial compounds that induce oxidative stress

It has been proposed that some antibiotics exert additional damage through reactive oxygen species (ROS) production. Since H2S protects neurons and cardiac muscle from oxidative stress, it has been hypothesized that bacterial H2S might, similarly, be a cellular protector against antibiotics. In Enterobacteriaceae, H2S can be produced by the cysJIH pathway, which uses sulfate as the sulfur source. CysB, in turn, is a positive regulator of cysJIH. At present, the role of S. Typhimurium cysJIH operon in the protection to reactive oxygen species (ROS) induced by antimicrobial compounds remains to be elucidated. In this work, we evaluated the role of cysJIH and cysB in ROS accumulation, superoxide dismutase (SOD) activity, reduced thiol accumulation, and H2S accumulation in S. Typhimurium, cultured in either sulfate or cysteine as the sole sulfur source. Furthermore, we assessed the effects of the addition of ceftriaxone (CEF) and menadione (MEN) in these same parameters. In sulfate as the sole sulfur source, we found that the cysJIH operon and the cysB gene were required to full growth in minimal media, independently on the addition of CEF or MEN. Most importantly, both cysJIH and cysB contributed to diminish ROS levels, increase the SOD activity, increase the reduced thiols, and increase the H2S levels in presence of CEF or MEN. Moreover, the cysJIH operon exhibited a CysB-dependent upregulation in presence of these two antimicrobials compounds. On the other hand, when cysteine was used as the sole sulfur source, we found that cysJIH operon was completely negligible, were only cysB exhibited similar phenotypes than the described for sulfate as sulfur source. Unexpectedly, CysB downregulated cysJIH operon when cysteine was used instead of sulfate, suggesting a complex regulation of this system.

Neuroprotective effects of aldehyde dehydrogenase 2 activation in rotenone-induced cellular and animal models of parkinsonism

Many studies have shown that mitochondrial aldehyde dehydrogenase 2 (ALDH2) functions as a cellular protector against oxidative stress by detoxification of cytotoxic aldehydes. Within dopaminergic neurons, dopamine is metabolized by monoamine oxidase to yield 3,4-dihydroxyphenylacetaldehyde (DOPAL) then converts to a less toxic acid product by ALDH. The highly toxic and reactive DOPAL has been hypothesized to contribute to the selective neurodegeneration in Parkinson's disease (PD). In this study, we investigated the neuroprotective mechanism and therapeutic effect of ALDH2 in rotenone models for parkinsonism. Overexpression of wild-type ALDH2 gene, but not the enzymatically deficient mutant ALDH2*2 (E504K), reduced rotenone-induced cell death. Application of a potent activator of ALDH2, Alda-1, was effective in protecting against rotenone-induced apoptotic cell death in both SH-SY5Y cells and primary cultured substantia nigra (SN) dopaminergic neurons. In addition, intraperitoneal administration of Alda-1 significantly reduced rotenone- or MPTP-induced death of SN tyrosine hydroxylase (TH)-positive dopaminergic neurons. The attenuation of rotenone-induced apoptosis by Alda-1 resulted from decreasing ROS accumulation, reversal of mitochondrial membrane potential depolarization, and inhibition of activation of proteins related to mitochondrial apoptotic pathway. The present study demonstrates that ALDH2 plays a crucial role in maintaining normal mitochondrial function to protect against neurotoxicity and that Alda-1 is effective in ameliorating mitochondrial dysfunction and inhibiting mitochondria-mediated apoptotic pathway. These results indicate that ALDH2 activation could be a neuroprotective therapy for PD.

The Proto-Oncoprotein c-Cbl Protects Cells against Oxidative Stress by Down- Regulating Apoptosis and is Highly Expressed in Several Cancers

Objective: To determine the role of c-Cbl in the apoptotic process, using several means, stressing the role of oxidative stress in cancer cells. Methods: Prostatic epithelial cell apopotosis of c-Cbl-/-mice were compared to wildtype mice (n: 6 per condition), upon testosterone-antagonist flutamide. c-Cbl-deficient mouse embryonic fibroblasts (MEFs) were compared to wild type MEFs under etoposide or hydrogen peroxide treatments. The use of c-Cbl RNA silencing in the human prostate adenocarcinoma cell line LNCaP allowed to reveal c-Cbl’s role in LNCaPs’ apoptosis. The role of the p38-MAPK stress pathway in the LNCAP c-Cbl anti-apoptotic effect as well as its relationship with the well-documented Grb2-associated Tyrosine-Kinase-Receptor (TKR) down-regulation were investigated, using c-Cbl and/or Grb2 RNA silencing. Human c-Cbl protein expression was analysed by Western blotting and immunostaining, comparing prostatic adenocarcinoma (x22) to benign prostatic hypertrophia (x6). In situ tissue microarrays were used to assess several human malignancies (x17 and x6 spots/tissue) and to compare the magnitude of c-Cbl and oxidative stress expression. Results: The cellular apoptotic threshold decreased in Mouse c-Cbl-/-prostatic cells and c-Cbl-/- MEFs. Only hydrogen peroxide in c-Cbl-/-MEFs induced apoptosis up to six times more than controls. Similar results were found in LNCaPs. c-Cbl down-regulates the activation of the apoptotic ASK1-p38MAPK stress pathway. c-Cbl is overexpressed in prostate, ovary, uterus, brain, lung, colon, rectum adenocarcinoma and in rhabdomyosarcoma. We found a correlation between malignant oxidative stress and c-Cbl over-expression. Conclusions: c-Cbl increases the cellular apoptotic threshold of wild type MEFs and mouse prostate cells. c-Cbl behaves as a strong cellular protector against oxidative stress in MEFs and LNCaPs. The p38-MAPK pathway is down-regulated by c-Cbl, possibly independently of the Grb2-associated TKR down-regulation. A high c-Cbl expression in several cancers often associated with high oxidative stress expression has been found, suggesting that c-Cbl could thereby promote their survival.

Trocas gasosas e conteúdo de carboidratos e compostos nitrogenados em pinhão-manso irrigado com águas residuária e salina

O objetivo deste trabalho foi avaliar alterações nas trocas gasosas e nos conteúdos de carboidratos e compostos nitrogenados, em pinhão-manso (Jatropha curcas) irrigado com águas residuária e salina. Empregou-se o delineamento em blocos ao acaso, com quatro tratamentos e quatro repetições: irrigação plena com água de abastecimento a 0,6 dS m-1 (controle); irrigação plena com água salinizada a 2,4 dS m-1 (SAL); e irrigação com água residuária de esgoto, plena (R100) e a 50% da capacidade de campo (R50). O tratamento R50 reduziu fortemente as trocas gasosas e a área foliar, comparado ao controle, seguido pelos tratamentos SAL e R100. A redução na fotossíntese diminuiu o nível de sacarose nas folhas, nos quatro tratamentos. Os teores de açúcares solúveis aumentaram nos tratamentos R50, SAL e R100, enquanto o conteúdo de amido permaneceu praticamente inalterado. Os conteúdos de prolina e glicina betaína aumentaram nos três tratamentos, mas a última foi mais importante, em termos quantitativos, como protetor celular e osmótico. A irrigação plena com água residuária induz efeitos similares aos causados pela irrigação com água salina. A irrigação limitada com água residuária causa estresse agudo às plantas, provavelmente pela combinação de deficiência hídrica e acúmulo de solutos no solo.

Production of native flagellin from Salmonella Typhimurium in a bioreactor and purification by tangential ultrafiltration

Flagellin is the structural protein and most abundant component of bacterial flagella. The flagellum filament contains around 20,000 - 100,000 subunits of 50 kDa flagellin that can have diverse biotechnological applications such as vaccine adjuvant and cellular protector during chemo- and radiotherapy. The main aim of this work was to study a production process of purified native FliC flagellin of Salmonella Typhimurium. The culture conditions in shakers were established with medium devoid of animal-derived components. In bioreactors, culture conditions were established in order to obtain flagellin from the culture supernatant by tangential ultrafiltration (TUF). The concentrated 750 kDa cut-off TUF fraction had a purification factor of 1.5 and a recovery yield of 52.2% for flagellin. The volumetric production of flagellin using the described procedure achieved around 307 mg/L of culture, which represented a significant improvement over previously reported methods. These results permit the development of production and purification processes that can be easily scaled up.

Effect of Liver Hypothermic Preservation: Exploration and Protection

Background/Aims: The principal aim of conservation is to maintain the viability of grafts. This requires the addition of a cellular protector allowing better conservation of the graft. The aim of this work is to evaluate the effect of trimetazidine (TMZ) addition to Wistar rat livers conserved in Krebs-Henseleit solution, compared to the livers preserved only in Krebs-Henseleit solution (24 h at 4°C). Methods: 40 Wistar female rats divided into 5 groups were used: the first group consists of nonpreserved livers, the second consists of livers preserved only in the Krebs-Henseleit solution, and the other 3 groups consist of livers preserved in Krebs solution with different concentrations of TMZ added (16.5, 49.5 and 165 μg/ml). Results: The obtained results show an improvement in the state of the liver in the presence of a high concentration of TMZ, which approaches normal physiological conditions. We note a clear diminution of transaminase activities, as well as an amelioration in metabolic capacities of the liver if the mitochondrial esterase pathway is supported in Wistar rats by a reduction of histological injuries. Conclusion: A TMZ concentration of 165 μg/ml clearly restored the metabolic capacities of the liver. Indeed, TMZ limited the appearance of necrotic areas and almost suppressed apoptotic cells.