Chasing great paths of Helmut Sies “Oxidative Stress”

Michael acceptor molecules in natural products and their mechanism of action

Purpose: Michael receptor molecules derived from plants are biologically active due to electrophilic groups in their structure. They can target nucleophilic residues on disease-related proteins, with significant therapeutic effects and low toxicity for many diseases. They provide a good option for relevant disease treatment. The aim of this study is to summarize the existing MAMs and their applications, and lay a foundation for the application of Michael receptor molecules in life science in the future. Methods: This review summarizes the published studies on Michael receptor molecules isolated from plants in literature databases such as CNKI, Wanfang Data, PubMed, Web of Science, ScienceDirect, and Wiley. Latin names of plants were verified through https://www.iplant.cn/. All relevant compound structures were verified through PubChem and literature, and illustrated with ChemDraw 20.0. Result: A total of 50 Michael receptor molecules derived from various plants were discussed. It was found that these compounds have similar pharmacological potential, most of them play a role through the Keap1-Nrf2-ARE pathway and the NF-κB pathway, and have biological activities such as antioxidant and anti-inflammatory. They can be used to treat inflammatory diseases and tumors. Conclusion: The Michael receptor molecule has electrophilicity due to its unsaturated aldehyde ketone structure, which can combine with nucleophilic residues on the protein to form complexes and activate or inhibit the protein pathway to play a physiological role. Michael receptor molecules can regulate the Keap1-Nrf2-ARE pathway and the NF-κB pathway. Michael receptor molecules can be used to treat diseases such as inflammation, cancer, oxidative stress, etc.

Stress-induced blood brain barrier disruption: Molecular mechanisms and signaling pathways

Stress is a nonspecific response to a threat or noxious stimuli with resultant damaging consequences. Stress is believed to be an underlying process that can trigger central nervous system disorders such as depression, anxiety, and post-traumatic stress disorder. Though the pathophysiological basis is not completely understood, data have consistently shown a pivotal role of inflammatory mediators and hypothalamo-pituitary-adrenal (HPA) axis activation in stress induced disorders. Indeed emerging experimental evidences indicate a concurrent activation of inflammatory signaling pathways and not only the HPA axis, but also, peripheral and central renin-angiotensin system (RAS). Furthermore, recent experimental data indicate that the HPA and RAS are coupled to the signaling of a range of central neuro-transmitter, -mediator and -peptide molecules that are also regulated, at least in part, by inflammatory signaling cascades and vice versa. More recently, experimental evidences suggest a critical role of stress in disruption of the blood brain barrier (BBB), a neurovascular unit that regulates the movement of substances and blood-borne immune cells into the brain parenchyma, and prevents peripheral injury to the brain substance. However, the mechanisms underlying stress-induced BBB disruption are not exactly known. In this review, we summarize studies conducted on the effects of stress on the BBB and integrate recent data that suggest possible molecular mechanisms and signaling pathways underlying stress-induced BBB disruption. Key molecular targets and pharmacological candidates for treatment of stress and related illnesses are also summarized.

Thioredoxin-1 PEGylation as an In Vitro Method for Drug Target Identification

Redox signaling in the cell, which is essential for cell physiology, involves proteins with free sulfhydryl groups (-SH). Among them, the thioredoxin system plays the most significant role. Many conditions associated with cell malignancies feature the higher expression of thioredoxin, making it an attractive target for new therapeutic drug development. Here we present a simple in vitro model of testing the interaction between thioredoxin and the putative drug. This method is relatively inexpensive and gives the Investigator a first screen of the drug properties, which can be essential for further experimental approaches.

Sida cordifolia accelerates wound healing process delayed by dexamethasone in rats: Effect on ROS and probable mechanism of action

ETHNO PHARMACOLOGICAL RELEVANCE

Sida cordifolia is used commonly in traditional systems of medicine (TSM) and as folk remedies for treating the wounds (both external and internal), infected area, rheumatic disorders, muscular weakness, tuberculosis, heart problems, bronchitis, neurological problems etc. Therefore, in order to authenticate the claims, a mechanism-oriented investigation of the wound healing properties of this plant is essential.

AIM OF THE STUDY

The overall aim of the present research is to understand the precise unknown cellular and molecular mechanism by which S. cordifolia accelerates wound healing delay caused by the steroidal drug dexamethasone. Here, we have also tried to quantify intracellular superoxide with the help of a unique fluoroprobe MitoSOX based on fluorescence measurements in yeast MATERIALS AND METHODS: Wound healing property of successive extracts (ethyl acetate, methanol and aqueous) of S. cordifolia against dexamethasone-induced retardation of wound healing in rats was studied. The various extracts of S. cordifolia were characterised by determining the various phytochemicals and quantifying the total phenolic content and flavonoidal content by High throughput assays. In order to know the probable mechanism of action of the successive fractionates, assessed the antioxidant activity both by in-vitro (DPPH-assay) and in-vivo methods in wild-type Saccharomyces cerevisiae BY 4743 (WT) and knock-out strain (Δtrx2) against H₂O₂-induced stress mediated damages. The cell survival was evaluated after exposure to the oxidizing reagent (4 mM H₂O₂) by two methods which included the ability of cells to proliferate on solid or liquid medium. The cell membrane integrity/amount of mitochondrial ROS was determined by treating the strains with extract/standard in presence of H₂O₂ and propidium iodide (PI)/MitoSOX Red RESULTS: During the preliminary in-vivo wound healing study, the period for complete re-epithelialization of the wound tissue was reduced significantly (pin the treatment groups as compared to the negative control group. The formulation HF₃ containing aqueous extract of S. cordifolia (SCA) showed highest wound healing potential against dexamethasone-retarded wounds in rats which justifies its traditional use. In the growth curve assay, the H₂O₂-induced growth arrest was restored by aqueous extract of S. cordifolia (SCA) in a concentration-dependent(pmanner both in the WT and Δtrx2 strains similar to the standard (ascorbic acid), H₂O₂ after 24 hours incubation which was also confirmed by the findings of CFU method. We got almost similar results of cell viability when stained with PI. The lower level of mitochondrial superoxide was indicated by a significant (preduction in the amount of MitoSOX stained cells, in the extract-treated group in contrast to the H₂O₂-stressed group.

CONCLUSION

It was concluded that HF₃ can be applied topically in hydrogel form in the case of delayed wound healing caused by the steroidal drug-dexamethasone, aptly justifying its traditional use. Regarding its mechanism of action, our findings report that the potent adaptive response of SCA-treated WT and Δtrx2 strains towards intracellular ROS specifically mitochondrial-ROS confirms its antioxidant potential. Moreover, as SCA was able to rescue the Δtrx2 strains from stress, it can be inferred that it might be able to induce the enzyme thioredoxin-II to restore redox homeostasis. The findings with the conditional mutant ∆trx2 are the first proof linking SCA action related to particular cellular pathways which may be because of the phenols and flavonoids and their synergistic effect.

Role of Mitochondrial Reactive Oxygen Species in the Activation of Cellular Signals, Molecules, and Function

Mitochondria are a major source of intracellular energy and reactive oxygen species in cells, but are also increasingly being recognized as a controller of cell death. Here, we review evidence of signal transduction control by mitochondrial superoxide generation via the nuclear factor-κB (NF-κB) and GATA signaling pathways. We have also reviewed the effects of ROS on the activation of MMP and HIF. There is significant evidence to support the hypothesis that mitochondrial superoxide can initiate signaling pathways following transport into the cytosol. In this study, we provide evidence of TATA signal transductions by mitochondrial superoxide. Oxidative phosphorylation via the electron transfer chain, glycolysis, and generation of superoxide from mitochondria could be important factors in regulating signal transduction, cellular homeostasis, and cell death.

A novel luminol-based enhanced chemiluminescence antioxidant capacity microplate assay for use in different biological matrices

INTRODUCTION

Reactive oxygen species (ROS) are normal metabolic products of living cells. However, a decrease of the defense mechanisms against the effects of ROS or increased ROS production maybe one important causative factor of cellular damage. A non-enzymatic scavenger system is considered to be responsible for the maintenance of total antioxidant capacity (TAC) as a protection against oxidative injuries that exist in all higher plants and in mammals as well.

METHODS

In our work, we optimized and validated a luminol-peroxidase-4-iodophenol-H₂O₂ enhanced chemiluminescence-based (ECL) TAC measurement technique. BSA was applied in the reagent to prevent peroxidase from auto-oxidation. The ECL method was suitable for plant extracts and for human blood serum as well. Our TAC technique was adapted to microplates and compared to ORAC assay using plant extracts.

RESULTS AND DISCUSSION

The ECL method is fast (10min) with an interassay precision of <10% as CV. TAC values of ethanolic extracts of 10 plant species did correlate (ECL vs ORAC assay data: r=0.84, 95% confidence interval, CI=0.78-0.89, P<0.001) but with systematic bias. Analysis of serum samples obtained from septic and control patients showed significantly higher TAC values in the patient group compared to those of controls (p<0.01). Moreover, we could discriminate between surviving and non-surviving patients, based on their TAC values (p<0.01). Pearson's statistics showed the strongest positive correlation with serum uric acid (r=0.73). Besides the routine laboratory parameters, our novel TAC method might give complementary information on the severity of systemic inflammation.

Estimation of tissue and crevicular fluid oxidative stress marker in premenopausal, perimenopausal and postmenopausal women with chronic periodontitis

OBJECTIVES

The aim of this study was to estimate tissue and gingival crevicular fluid (GCF) levels of the oxidative stress marker 8-hydroxy-2'-deoxyguanosine (8-OHdG) in premenopausal, perimenopausal and postmenopausal women with chronic periodontitis.

BACKGROUND

Oxidative stress has been implicated in the etiopathogenesis of periodontitis and menopause induces oxidative stress.

MATERIALS AND METHODS

According to Stages of Reproductive Aging Workshop (STRAW) criteria, women diagnosed with periodontitis were subdivided into three groups of 31 participants each 1. Premenopausal 2. Perimenopausal and 3. Postmenopausal. GCF and gingival tissue samples were collected from sites with maximum probing depth. Tissue DNA was extracted from the gingival sample and 8-OHdG in the extracted DNA, and GCF samples were measured using ELISA.

RESULTS

There was a highly significant difference in the overall GCF 8-OHdG levels among the three groups with the pairwise difference being highly significant between the premenopausal-postmenopausal groups and perimenopausal-postmenopausal groups. However, no overall significant differences in tissue 8-OHdG levels were found among the three groups. Pairwise, highly significant differences were found between the premenopausal-postmenopausal groups and perimenopausal-postmenopausal groups for tissue 8-OHdG levels. No significant correlations were found between various measure of periodontal disease and GCF/tissue 8-OHdG levels among all the groups.

CONCLUSION

Premenopausal-postmenopausal and perimenopausal-postmenopausal transition resulted in significant increase in tissue and GCF 8-OHdG levels. However, no association was found between stages of reproductive ageing and tissue levels of 8-OHdG.