Myocardial cell mitochondria-targeted mesoporous polydopamine nanoparticles eliminate inflammatory damage in cardiovascular disease

Excess reactive oxide species (ROS) is a direct factor in myocardial injury death, thus anti-oxidant therapy is a necessary measure to prevent rapid death of cardiomyocyte cell. Cysteine (Cys) is a potent antioxidant but easily become instability because of the hyperactivity. Therefore, in order to protect the the stability of Cys, we according to the mitochondria are the main sites of ROS production, utilized the loading and ROS scavenging capacity of mesoporous polydopamine (mPDA) constructed a nanosystem targeting mitochondria with effectively ROS elimination capability by loading cysteine (Cys-mPDA@TPP). The mesoporous structure of mPDA effectively inhibited the advance reaction and hyperactivity of Cys, thus effectively improving its stability that reached the double-collaborative treatment excess ROS. In particular, Cys-mPDA@TPP achieved directly reacting with ROS in mitochondria under the targeting of triphenylphosphine (TPP), not only enhancing the elimination efficiency of ROS, but also preventing mitochondrial dysfunction of monocyte-macrophage. Furthermore, with double-collaborative ROS elimination, Cys-mPDA@TPP effectively prevent the damage of cardiomyocyte cell through inhibiting macrophage inflammatory response. Therefore, this study provides a new therapeutic strategy for myocardial inflammatory injury.

N-acetyl-cysteine in Schizophrenia: Potential Role on the Sensitive Cysteine Proteome

BACKGROUND

N-acetyl-cysteine (NAC) has shown widespread utility in different psychiatric disorders, including a beneficial role in schizophrenic patients. Although the replenishment of glutathione and the antioxidant activity of NAC have been suggested as the mechanisms that improve such a wide range of disorders, none seems to be sufficiently specific to explain these intriguing effects. A sensitive cysteine proteome is emerging as a functional and structural network of interconnected Sensitive Cysteine-containing Proteins (SCCPs) that together with reactive species and the cysteine/ glutathione cycles can regulate the bioenergetic metabolism, the redox homeostasis and the cellular growth, differentiation and survival, acting through different pathways that are regulated by the same thiol radical in cysteine residues.

OBJECTIVE

Since this sensitive cysteine network has been implicated in the pathogenesis of Parkinson's and Alzheimer's diseases, I have reviewed if the proteins that play a role in schizophrenia can be classified as SCCPs.

RESULTS

The results show that the principal proteins playing a role in schizophrenia can be classified as SCCPs, suggesting that the sensitive cysteine proteome (cysteinet) is defective in this type of psychosis.

CONCLUSION

The present review proposes that there is a deregulation of the sensitive cysteine proteome in schizophrenia as the consequence of a functional imbalance among different SCCPs, which play different functions in neurons and glial cells. In this context, the role of NAC to restore and prevent schizophrenic disorders is discussed.

SufB intein of Mycobacterium tuberculosis as a sensor for oxidative and nitrosative stresses

Inteins are mobile genetic elements that self-splice at the protein level. Mycobacteria have inteins inserted into several important genes, including those corresponding to the iron-sulfur cluster assembly protein SufB. Curiously, the SufB inteins are found primarily in mycobacterial species that are potential human pathogens. Here we discovered an exceptional sensitivity of Mycobacterium tuberculosis SufB intein splicing to oxidative and nitrosative stresses when expressed in Escherichia coli. This effect results from predisposition of the intein's catalytic cysteine residues to oxidative and nitrosative modifications. Experiments with a fluorescent reporter system revealed that reactive oxygen species and reactive nitrogen species inhibit SufB extein ligation by forcing either precursor accumulation or N-terminal cleavage. We propose that splicing inhibition is an immediate, posttranslational regulatory response that can be either reversible, by inducing precursor accumulation, or irreversible, by inducing N-terminal cleavage, which may potentially channel mycobacteria into dormancy under extreme oxidative and nitrosative stresses.

Ethanol Attenuates Histiotrophic Nutrition Pathways and Alters the Intracellular Redox Environment and Thiol Proteome during Rat Organogenesis

Ethanol (EtOH) is a reactive oxygen-generating teratogen involved in the etiology of structural and functional developmental defects. Embryonic nutrition, redox environment, and changes in the thiol proteome following EtOH exposures (1.56.0 mg/ml) were studied in rat whole embryo culture. Glutathione (GSH) and cysteine (Cys) concentrations with their respective intracellular redox potentials (Eh) were determined using high-performance liquid chromatography. EtOH reduced GSH and Cys concentrations in embryo (EMB) and visceral yolk sac (VYS) tissues, and also in yolk sac and amniotic fluids. These changes produced greater oxidation as indicated by increasingly positive Eh values. EtOH reduced histiotrophic nutrition pathway activities as measured by the clearance of fluorescin isothiocyanate (FITC)-albumin from culture media. A significant decrease in total FITC clearance was observed at all concentrations, reaching approximately 50% at the highest dose. EtOH-induced changes to the thiol proteome were measured in EMBs and VYSs using isotope-coded affinity tags. Decreased concentrations for specific proteins from cytoskeletal dynamics and endocytosis pathways (α-actinin, α-tubulin, cubilin, and actin-related protein 2); nuclear translocation (Ran and RanBP1); and maintenance of receptor-mediated endocytosis (cubilin) were observed. Kyoto encyclopedia of genes and genomes (KEGG) pathway analysis also identified a decrease in ribosomal proteins in both EMB and VYS. Results show that EtOH interferes with nutrient uptake to reduce availability of amino acids and micronutrients required by the conceptus. Intracellular antioxidants such as GSH and Cys are depleted following EtOH and Eh values increase. Thiol proteome analysis in the EMB and VYS show selectively altered actin/cytoskeleton, endocytosis, ribosome biogenesis and function, nuclear transport, and stress-related responses.

Protein S-glutathionylation: from current basics to targeted modifications

The interaction between antioxidant glutathione and the free thiol in susceptible cysteine residues of proteins leads to reversible protein S-glutathionylation. This reaction ensures cellular homeostasis control (as a common redox-dependent post-translational modification associated with signal transduction) and intervenes in oxidative stress-related cardiovascular pathology (as initiated by redox imbalance). The purpose of this review is to evaluate the recent knowledge on protein S-glutathionylation in terms of chemistry, broad cellular intervention, specific quantification, and potential for therapeutic exploitation. The data bases searched were Medline and PubMed, from 2009 to 2014 (term: glutathionylation). Protein S-glutathionylation ensures protection of protein thiols against irreversible over-oxidation, operates as a biological redox switch in both cell survival (influencing kinases and protein phosphatases pathways) and cell death (by potentiation of apoptosis), and cross-talks with phosphorylation and with S-nitrosylation. Collectively, protein S-glutathionylation appears as a valuable biomarker for oxidative stress, with potential for translation into novel therapeutic strategies.

Antioxidative properties of 4-methylumbelliferone are related to antibacterial activity in the silkworm (Bombyx mori) digestive tract

Umbelliferones have gained significant attention due to their tumor-inhibitory effects in vitro. This study was undertaken to examine the impact of umbelliferones in an invertebrate model organism, Bombyx mori, to assess the underlying antimicrobial activities via antioxidation in vivo. Oral administration of 4 mM 4-methylumbelliferone (4-MU), a model umbelliferone drug, in B. Mori larvae caused a rapid increase in reactive oxygen species, such as hydrogen peroxide (H2O2) and antimicrobial activity in the digestive tract. In addition, a significant increase in total antioxidant capacity as well as superoxide anion radical-inhibiting activity and reduced glutathione were detected. The antioxidant defense system was activated following induction of H2O2, resulting in a significant rise in catalase (50-66 %) and glutathione peroxidase (175 %) activities, which were helpful in defending digestive tract cells against oxidative injury. These results help in understanding the anticancer mechanism of 4-MU based on its antioxidation in organisms.

Alleviation of methyl viologen-mediated oxidative stress by Brassica juncea annexin-3 in transgenic Arabidopsis

Plant annexins function as calcium-dependent or -independent phospholipid binding proteins and constitute about 0.1% of total cellular proteins. Some of them were reported to antagonize oxidative stress and protect plant cells. Brassica juncea annexin-3 (AnnBj3) was recently discovered. To gain insight into a possible function of AnnBj3 in oxidative stress response, we investigated the resistance of Arabidopsis thaliana plants expressing AnnBj3 constitutively. Here we report that, AnnBj3 attenuates methyl viologen-mediated oxidative stress in plants. It protected photosynthesis and plasma membrane from methyl viologen-mediated oxidative damage. AnnBj3 detoxifies hydrogen peroxide and showed antioxidative property in vitro. The protein increased total peroxidase activity in transgenics and interfered with other cellular antioxidants, thereby giving an overall cellular protection against methyl viologen-induced cytotoxicity.

Antioxidative capacity in the fat body of Bombyx mori is increased following oral administration of 4-methylumbelliferone

Plant sources of umbelliferones have tumor-inhibitory effects at the cellular level. However, their physiological functions in animals are largely unresolved. In this study, we provide evidence to show that 4-methylumbelliferone (4-MU) participates in the regulation of antioxidative capacity in the fat body of Bombyx mori, a tissue similar to mammalian liver in this model invertebrate. Larvae (3rd day of the 5th instar) were orally exposed to 4 mM 4-MU, an umbelliferone, which swiftly induced the generation of a large number of ROS (e.g. H2O2 increased 6 to 8-fold), and 4-MU was detected in the fat body 8 min after administration. In addition, the activities of CAT and GPx were up-regulated 4 to 11-fold and 2 to 16-fold, respectively, and were helpful in defending fat body cells against oxidative injury in combination with NADPH. Furthermore, significant increases in the contents of T-AOC (up to approx. 2-fold), antioxidants of ASAFR (by 2 to 4-fold) and GSH were detected.

The effects of para-chloromercuribenzoic acid and different oxidative and sulfhydryl agents on a novel, non-AT1, non-AT2 angiotensin binding site identified as neurolysin

A novel, non-AT1, non-AT2 brain binding site for angiotensin peptides that is unmasked by p-chloromercuribenzoate (PCMB) has been identified as a membrane associated variant of neurolysin. The ability of different organic and inorganic oxidative and sulfhydryl reactive agents to unmask or inhibit 125I-Sar1Ile8 angiotensin II (SI-Ang II) binding to this site was presently examined. In tissue membranes from homogenates of rat brain and testis incubated in assay buffer containing losartan (10 μM) and PD123319 (10 μM) plus 100 μM PCMB, 5 of the 39 compounds tested inhibited 125I-SI Ang II binding in brain and testis. Mersalyl acid, mercuric chloride (HgCl2) and silver nitrate (AgNO3) most potently inhibited 125I-SI Ang II binding with IC50s ~1-20 μM. This HgCl2 inhibition was independent of any interaction of HgCl2 with angiotensin II (Ang II) based on the lack of effect of HgCl2 on the dipsogenic effects of intracerebroventricularly administered Ang II and 125I-SI Ang II binding to AT1 receptors in the liver. Among sulfhydryl reagents, cysteamine and reduced glutathione (GSH), but not oxidized glutathione (GSSG) up to 1mM, inhibited PCMB-unmasked 125I-SI Ang II binding in brain and testis. Thimerosal and 4-hydroxymercuribenzoate moderately inhibited PCMB-unmasked 125I-SI Ang II binding in brain and testis at 100 μM; however, they also unmasked non-AT1, non-AT2 binding independent of PCMB. 4-Hydroxybenzoic acid did not promote 125 I-SI Ang II binding to this binding site indicating that only specific organomercurial compounds can unmask the binding site. The common denominator for all of these interacting substances is the ability to bind to protein cysteine sulfur. Comparison of cysteines between neurolysin and the closely related enzyme thimet oligopeptidase revealed an unconserved cysteine (cys650, based on the full length variant) in the proposed ligand binding channel (Brown et al., 2001) [45] near the active site of neurolysin. It is proposed that the mercuric ion in PCMB and closely related organomercurial compounds binds to cys650, while the acidic anion forms an ionic bond with a nearby arginine or lysine along the channel to effect a conformational change in neurolysin that promotes Ang II binding.

Cellular redox, epigenetics and diseases

Since the Central dogma of Molecular Biology was proposed about 40 years ago; our understanding of the intricacies of gene regulation has undergone tectonic shifts almost every decade. It is now widely accepted that the complexity of an organism is not directed by the sheer number of genes it carries but how they are decoded by a myriad of regulatory modules. Over the years, it has emerged that the organizations chromatins and its remodeling; splicing and polyadenylation of pre-mRNAs, stability and localization of mRNAs and modulation of their expression by non-coding and miRNAs play pivotal roles in metazoan gene expression. Nevertheless, in spite of tremendous progress in our understanding of all these mechanisms of gene regulation, the way these events are coordinated leading towards a highly defined proteome of a given cell type remains enigmatic. In that context, the structures of many metazoan genes cannot fully explain their pattern of expression in different tissues, especially during embryonic development and progression of various diseases. Further, numerous studies done during the past quarter of a century suggested that the heritable states of transcriptional activation or repression of a gene can be influenced by the covalent modifications of constituent bases and associated histones; its chromosomal context and long-range interactions between various chromosomal elements (Holliday 1987; Turner 1998; Lyon 1993). However, molecular dissection of these phenomena is largely unknown and is an exciting topic of research under the sub-discipline epigenetics (Gasser et al. 1998).

Nuclear transport: a switch for the oxidative stress-signaling circuit?

Imbalances in the formation and clearance of reactive oxygen species (ROS) can lead to oxidative stress and subsequent changes that affect all aspects of physiology. To limit and repair the damage generated by ROS, cells have developed a multitude of responses. A hallmark of these responses is the activation of signaling pathways that modulate the function of downstream targets in different cellular locations. To this end, critical steps of the stress response that occur in the nucleus and cytoplasm have to be coordinated, which makes the proper communication between both compartments mandatory. Here, we discuss the interdependence of ROS-mediated signaling and the transport of macromolecules across the nuclear envelope. We highlight examples of oxidant-dependent nuclear trafficking and describe the impact of oxidative stress on the transport apparatus. Our paper concludes by proposing a cellular circuit of ROS-induced signaling, nuclear transport and repair.

Aldehyde dehydrogenase 7A1 (ALDH7A1) attenuates reactive aldehyde and oxidative stress induced cytotoxicity

Mammalian aldehyde dehydrogenase 7A1 (ALDH7A1) is homologous to plant ALDH7B1 which protects against various forms of stress such as increased salinity, dehydration and treatment with oxidants or pesticides. Deleterious mutations in human ALDH7A1 are responsible for pyridoxine-dependent and folinic acid-responsive seizures. In previous studies, we have shown that human ALDH7A1 protects against hyperosmotic stress presumably through the generation of betaine, an important cellular osmolyte, formed from betaine aldehyde. Hyperosmotic stress is coupled to an increase in oxidative stress and lipid peroxidation (LPO). In this study, cell viability assays revealed that stable expression of mitochondrial ALDH7A1 in Chinese hamster ovary (CHO) cells provides significant protection against treatment with the LPO-derived aldehydes hexanal and 4-hydroxy-2-nonenal (4HNE) implicating a protective function for the enzyme during oxidative stress. A significant increase in cell survival was also observed in CHO cells expressing either mitochondrial or cytosolic ALDH7A1 treated with increasing concentrations of hydrogen peroxide (H(2)O(2)) or 4HNE, providing further evidence for anti-oxidant activity. In vitro enzyme activity assays indicate that human ALDH7A1 is sensitive to oxidation and that efficiency can be at least partially restored by incubating recombinant protein with the thiol reducing agent β-mercaptoethanol (BME). We also show that after reactivation with BME, recombinant ALDH7A1 is capable of metabolizing the reactive aldehyde 4HNE. In conclusion, ALDH7A1 mechanistically appears to provide cells protection through multiple pathways including the removal of toxic LPO-derived aldehydes in addition to osmolyte generation.