Mitochondrial ROS production under cellular stress: comparison of different detection methods

Isosteric Replacement of Sulfur to Selenium in a Thiosemicarbazone: Promotion of Zn(II) Complex Dissociation and Transmetalation to Augment Anticancer Efficacy

We implemented isosteric replacement of sulfur to selenium in a novel thiosemicarbazone (PPTP4c4mT) to create a selenosemicarbazone (PPTP4c4mSe) that demonstrates potentiated anticancer efficacy and selectivity. Their design specifically incorporated cyclohexyl and styryl moieties to sterically inhibit the approach of their Fe(III) complexes to the oxy-myoglobin heme plane. Importantly, in contrast to the Fe(III) complexes of the clinically trialed thiosemicarbazones Triapine, COTI-2, and DpC, the Fe(III) complexes of PPTP4c4mT and PPTP4c4mSe did not induce detrimental oxy-myoglobin oxidation. Furthermore, PPTP4c4mSe demonstrated more potent antiproliferative activity than the homologous thiosemicarbazone, PPTP4c4mT, with their selectivity being superior or similar, respectively, to the clinically trialed thiosemicarbazone, COTI-2. An advantageous property of the selenosemicarbazone Zn(II) complexes relative to their thiosemicarbazone analogues was their greater transmetalation to Cu(II) complexes in lysosomes. This latter effect probably promoted their antiproliferative activity. Both ligands down-regulated multiple key receptors that display inter-receptor cooperation that leads to aggressive and resistant breast cancer.

Potential Role of Nrf2, HER2, and ALDH in Cancer Stem Cells: A Narrative Review

Cancer is one of the main causes of death among humans, second only to cardiovascular diseases. In recent years, numerous studies have been conducted on the pathophysiology of cancer, and it has been established that this disease is developed by a group of stem cells known as cancer stem cells (CSCs). Thus, cancer is considered a stem cell disease; however, there is no comprehensive consensus about the characteristics of these cells. Several different signaling pathways including Notch, Hedgehog, transforming growth factor-β (TGF-β), and WNT/β-catenin pathways cause the self-renewal of CSCs. CSCs change their metabolic pathways in order to access easy energy. Therefore, one of the key objectives of researchers in cancer treatment is to destroy CSCs. Nuclear factor erythroid 2-related factor 2 (Nrf2) plays an essential role in the protection of CSCs from reactive oxygen species (ROS) and chemotherapeutic agents by regulating antioxidants and detoxification enzymes. Human epidermal growth factor receptor 2 (HER2) is a member of the tyrosine kinase receptor family, which contributes to the protection of cancer cells against treatment and implicated in the invasion, epithelial-mesenchymal transition (EMT), and tumorigenesis. Aldehyde dehydrogenases (ALDHs) are highly active in CSCs and protect the cells against damage caused by active aldehydes through the regulation of aldehyde metabolism. On the other hand, ALDHs promote the formation and maintenance of tumor cells and lead to drug resistance in tumors through the activation of various signaling pathways, such as the ALDH1A1/HIF-1α/VEGF axis and Wnt/β-catenin, as well as changing the intracellular pH value. Given the growing body of information in this field, in the present narrative review, we attempted to shed light on the function of Nrf2, HER2, and ALDH in CSCs.

Nickel oxide nanoparticles: A new generation nanoparticles to combat bacteria Xanthomonas oryzae pv. oryzae and enhance rice plant growth

Recently, nanotechnology is among the most promising technologies used in all areas of research. The production of metal nanoparticles using plant parts has received significant attention for its environmental friendliness and effectiveness. Therefore, we investigated the possible applications of biological synthesized nickel oxide nanoparticles (NiONPs). In this study, NiONPs were synthesized through biological method using an aqueous extract of saffron stigmas (Crocus sativus L). The structure, morphology, purity, and physicochemical properties of the obtained NPs were confirmed through Scanning/Transmission Electron Microscopy attached with Energy Dispersive Spectrum, X-ray Diffraction, and Fourier transform infrared. The spherically shaped NiONPs were found by Debye Scherer's formula to have a mean dimension of 41.19 nm. The application of NiONPs in vitro at 50, 100, and 200 μg/mL, respectively, produced a clear region of 2.0, 2.2, and 2.5 cm. Treatment of Xoo cell with NiONPs reduced the growth and biofilm formation, respectively, by 88.68% and 83.69% at 200 μg/mL. Adding 200 μg/mL NiONPs into Xoo cells produced a significant amount of ROS in comparison with the control. Bacterial apoptosis increased dramatically from 1.05% (control) to 99.80% (200 μg/mL NiONPs). When compared to the control, rice plants treated with 200 μg/mL NiONPs significantly improved growth characteristics and biomass. Interestingly, the proportion of diseased leaf area in infected plants with Xoo treated with NiONPs reduced to 22% from 74% in diseased plants. Taken together, NiONPs demonstrates its effectiveness as a promising tool as a nano-bactericide in managing bacterial infection caused by Xoo.

Alcohol Impairs Bioenergetics and Differentiation Capacity of Myoblasts from Simian Immunodeficiency Virus-Infected Female Macaques

Alcohol misuse and HIV independently induce myopathy. We previously showed that chronic binge alcohol (CBA) administration, with or without simian immunodeficiency virus (SIV), decreases differentiation capacity of male rhesus macaque myoblasts. We hypothesized that short-term alcohol and CBA/SIV would synergistically decrease differentiation capacity and impair bioenergetic parameters in female macaque myoblasts. Myoblasts from naïve (CBA-/SIV-), vehicle [VEH]/SIV, and CBA/SIV (N = 4-6/group) groups were proliferated (3 days) and differentiated (5 days) with 0 or 50 mM ethanol (short-term). CBA/SIV decreased differentiation and increased non-mitochondrial oxygen consumption rate (OCR) versus naïve and/or VEH/SIV. Short-term alcohol decreased differentiation; increased maximal and non-mitochondrial OCR, mitochondrial reactive oxygen species (ROS) production, and aldolase activity; and decreased glycolytic measures, ATP production, mitochondrial membrane potential (ΔΨm), and pyruvate kinase activity. Mitochondrial ROS production was closely associated with mitochondrial network volume, and differentiation indices were closely associated with key bioenergetic health and function parameters. Results indicate that short-term alcohol and CBA non-synergistically decrease myoblast differentiation capacity. Short-term alcohol impaired myoblast glycolytic function, driving the bioenergetic deficit. Results suggest potentially differing mechanisms underlying decreased differentiation capacity with short-term alcohol and CBA, highlighting the need to elucidate the impact of different alcohol use patterns on myopathy.

Unimolecular Self-Assembled Hemicyanine-Oleic Acid Conjugate Acts as a Novel Succinate Dehydrogenase Inhibitor to Amplify Photodynamic Therapy and Eliminate Cancer Stem Cells

Photodynamic therapy with reactive oxygen species production is a prospective treatment to combat cancer stem cells (CSCs). However, the innate drawbacks, including short lifetime and diffusion distance of reactive oxygen species and hypoxia within solid tumors, have become bottlenecks for clinical applications of photodynamic therapy. Here, we develop a mitochondria-targeting hemicyanine-oleic acid conjugate (CyOA), which can self-assemble into supramolecular nanoparticles (NPs) without any exogenous excipients. CyOA is also shown for targeting the mitochondrial complex II protein succinate dehydrogenase to inhibit oxidative phosphorylation and reverse tumor hypoxia, resulting in 50.4-fold higher phototoxicity against breast cancer stem cells (BCSCs) compared to SO3-CyOA NPs that cannot target to mitochondria. In 4T1 and BCSC tumor models, CyOA NPs achieve higher tumor inhibition and less lung metastasis nodules compared to the clinically used photosensitizer Hiporfin. This study develops a self-assembled small molecule that can serve as both oxidative phosphorylation inhibitor and photosensitizer for eradication of CSCs and treatment of solid tumors.

Neutrophils and the Systemic Inflammatory Response Syndrome (SIRS)

We are not entirely able to understand, assess, and modulate the functioning of the immune system in clinical situations that lead to a systemic inflammatory response. In the search for diagnostic and treatment strategies (which are still far from perfect), it became very important to study the pathogenesis and participation of endogenous inflammation mediators. This study attempts to more precisely establish the role of neutrophils in individual phenomena occurring during an inflammatory and anti-inflammatory reaction, taking into account their cidal, immunoregulatory, and reparative abilities. Pro- and anticoagulatory properties of endothelium in systemic inflammatory response syndrome (SIRS) are emphasised, along with the resulting clinical implications (the application of immunotherapy using mesenchymal stem/stromal cells (MSCs) or IL-6 antagonists in sepsis and COVID-19 treatment, among others). Special attention is paid to reactive oxygen species (ROS), produced by neutrophils activated during "respiratory burst" in the course of SIRS; the protective and pathogenic role of these endogenous mediators is highlighted. Moreover, clinically useful biomarkers of SIRS (neutrophil extracellular traps, cell-free DNA, DAMP, TREMs, NGAL, miRNA, selected cytokines, ROS, and recognised markers of endothelial damage from the group of adhesins by means of immunohistochemical techniques) related to the neutrophils are presented, and their role in the diagnosing and forecasting of sepsis, burn disease, and COVID-19 is emphasised. Finally, examples of immunomodulation of sepsis and antioxidative thermal injury therapy are presented.

An integrated strategy to explore the potential role of melatonin against copper-induced adrenaline toxicity in rat cardiomyocytes: Insights into oxidative stress, inflammation, and apoptosis

AIMS

Circumstantial anxiety as well as chronic stress may stimulate the release of stress hormones including catecholamines. Adrenaline toxicity has been implicated in many cardiovascular conditions. Considering previous literature that suggests the oxidative potential of the adrenaline-copper entity, we have investigated its potential nocuous role in isolated adult rat cardiomyocytes, the underlying molecular mechanism, and its possible protection by melatonin.

MAIN METHODS

Given the mechanistic congruity of adrenaline-copper (AC) with the well-established H₂O₂-copper-ascorbate (HCA) system of free radical generation, we have used the latter as a representative model to study the cytotoxic nature of AC. We further investigated the cardioprotective efficacy of melatonin in both the stress models through scanning electron microscopy, immunofluorescence, flow cytometry, and western blot analysis.

KEY FINDINGS

Results show that melatonin significantly protects AC-treated cardiomyocytes from ROS-mediated membrane damage, disruption of mitochondrial membrane potential, antioxidant imbalance, and distortion of cellular morphology. Melatonin protects cardiomyocytes from inflammation by downregulating pro-inflammatory mediators viz., COX-2, NF-κB, TNF-α, and upregulating anti-inflammatory IL-10. Melatonin significantly ameliorated cardiomyocyte apoptosis in AC and HCA-treated cells as evidenced by decreased BAX/BCL-2 ratio and subsequent suppression of caspase-9 and caspase-3 levels. The isothermal calorimetric study revealed that melatonin inhibits the binding of adrenaline bitartrate with copper in solution, which fairly explains the rescue potential of melatonin against AC-mediated toxicity in cardiomyocytes.

SIGNIFICANCE

Findings suggest that the multipronged strategy of melatonin that includes its antioxidant, anti-inflammatory, anti-apoptotic, and overall cardioprotective ability may substantiate its potential therapeutic efficacy against adrenaline-copper-induced damage and death of adult rat cardiomyocytes.

A systematic study on the use of multifunctional nanodiamonds for neuritogenesis and super-resolution imaging

BACKGROUND

Regeneration of defective neurons in central nervous system is a highlighted issue for neurodegenerative disease treatment. Various tissue engineering approaches have focused on neuritogenesis to achieve the regeneration of damaged neuronal cells because damaged neurons often fail to achieve spontaneous restoration of neonatal neurites. Meanwhile, owing to the demand for a better diagnosis, studies of super-resolution imaging techniques in fluorescence microscopy have triggered the technological development to surpass the classical resolution dictated by the optical diffraction limit for precise observations of neuronal behaviors. Herein, the multifunctional nanodiamonds (NDs) as neuritogenesis promoters and super-resolution imaging probes were studied.

METHODS

To investigate the neuritogenesis-inducing capability of NDs, ND-containing growing medium and differentiation medium were added to the HT-22 hippocampal neuronal cells and incubated for 10 d. In vitro and ex vivo images were visualized through custom-built two-photon microscopy using NDs as imaging probes and the direct stochastic optical reconstruction microscopy (dSTORM) process was performed for the super-resolution reconstruction owing to the photoblinking properties of NDs. Moreover, ex vivo imaging of the mouse brain was performed 24 h after the intravenous injection of NDs.

RESULTS

NDs were endocytosed by the cells and promoted spontaneous neuritogenesis without any differentiation factors, where NDs exhibited no significant toxicity with their outstanding biocompatibility. The images of ND-endocytosed cells were reconstructed into super-resolution images through dSTORM, thereby addressing the problem of image distortion due to nano-sized particles, including size expansion and the challenge in distinguishing the nearby located particles. Furthermore, the ex vivo images of NDs in mouse brain confirmed that NDs could penetrate the blood-brain barrier (BBB) and retain their photoblinking property for dSTORM application.

CONCLUSIONS

It was demonstrated that the NDs are capable of dSTORM super-resolution imaging, neuritogenic facilitation, and BBB penetration, suggesting their remarkable potential in biological applications.

Mechanical Regulation of Mitochondrial Dynamics and Function in a 3D-Engineered Liver Tumor Microenvironment

It has become evident that physical stimuli of the cellular microenvironment transmit mechanical cues regulating key cellular functions, such as proliferation, migration, and malignant transformation. Accumulating evidence suggests that tumor cells face variable mechanical stimuli that may induce metabolic rewiring of tumor cells. However, the knowledge of how tumor cells adapt metabolism to external mechanical cues is still limited. We therefore designed soft 3D collagen scaffolds mimicking a pathological mechanical environment to decipher how liver tumor cells would adapt their metabolic activity to physical stimuli of the cellular microenvironment. Here, we report that the soft 3D microenvironment upregulates the glycolysis of HepG2 and Alexander cells. Both cell lines adapt their mitochondrial activity and function under growth in the soft 3D microenvironment. Cells grown in the soft 3D microenvironment exhibit marked mitochondrial depolarization, downregulation of mitochondrially encoded cytochrome c oxidase I, and slow proliferation rate in comparison with stiff monolayer cultures. Our data reveal the coupling of liver tumor glycolysis to mechanical cues. It is proposed here that soft 3D collagen scaffolds can serve as a useful model for future studies of mechanically regulated cellular functions of various liver (potentially other tissues as well) tumor cells.

A novel lonidamine derivative targeting mitochondria to eliminate cancer stem cells by blocking glutamine metabolism

Cancer stem cells (CSCs) have been blamed as the main culprit of tumor initiation, progression, metastasis, chemoresistance, and recurrence. However, few anti-CSCs agents have achieved clinical success so far. Here we report a novel derivative of lonidamine (LND), namely HYL001, which selectively and potently inhibits CSCs by targeting mitochondria, with 380-fold and 340-fold lower IC₅₀ values against breast cancer stem cells (BCSCs) and hepatocellular carcinoma stem cells (HCSCs), respectively, compared to LND. Mechanistically, we reveal that HYL001 downregulates glutaminase (GLS) expression to block glutamine metabolism, blunt tricarboxylic acid cycle, and amplify mitochondrial oxidative stress, leading to apoptotic cell death. Therefore, HYL001 displays significant antitumor activity in vivo, both as a single agent and combined with paclitaxel. Furthermore, HYL001 represses CSCs of fresh tumor tissues derived from liver cancer patients. This study provides critical implications for CSCs biology and development of potent anti-CSCs drugs.

Boron-enriched rice-like homologous carbon nanoclusters with a 51.5% photoluminescent quantum yield for highly sensitive determination of endogenous hydroxyl radicals in living cells

Exploring the ultrahigh quantum efficiency of a carbon-based probe via a green and simple technique, and utilisation of its sensing ability for highly bioactive molecule detection is still highly challenging. Herein, we prepared a novel boron-enriched rice-like homologous carbon nanoclusters (BRCNs) with an ultrahigh quantum efficiency of ∼51.5% by introduction of a conjugated structure attached to the CN bond and an electron-withdrawing boron active centre. Unexpectedly, the BRCNs obtained showed a stable dispersion of rice-like carbon nanograins, composed of small carbon dot assembled nanoclusters with an average diameter size of ∼30 nm, and containing boron units of ∼24.68 at%. What's exciting is that the BRCNs obtained exhibited an "on-off-on" three-state emission with the addition of an hydroxyl radical (OH˙) and its antioxidants. Thus, two distinctive fluorescent responses for OH˙ and antioxidants based on the BRCN probe had been developed, and the mechanism has been determined using TEM, XPS, FT-IR, FL, UV-vis spectrophotometry, UPS and fluorescent lifetimes. The OH˙, generated from the Fenton's reagent, preferentially attack the electron-deficient vacancy p orbit of the boron atom in the surface of the BRCNs, which results in the boron atom being easily substituted/attacked by OH˙, and leading to spontaneous aggregation induced quenching (AIQ) due to the existence of a strong intermolecular hydrogen bond between denatured BRCNs. Furthermore, the proposed method was also successfully applied to monitor endogenous OH˙ generation in HeLa cells by confocal imaging, which could be used for elucidating OH˙-induced oxidative damage to biological tissues and proteins.

Mitochondrial DNA as a marker for treatment-response in post-traumatic stress disorder

Post-traumatic stress disorder (PTSD) is a serious mental health condition thought to be mediated by a dysregulated stress response system. Stress, especially chronic stress, affects mitochondrial activity and their efficiency in duplicating their genomes. Human cells contain numerous mitochondria that harbor multiple copies of their own genome, which consist of a mixture of wild type and variant mtDNA - a condition known as mitochondrial heteroplasmy. Number of mitochondrial genomes in a cell and the degree of heteroplasmy may serve as an indicator of mitochondrial allostatic load. Changes in mtDNA copy number and the proportion of variant mtDNA may be related to mental disorders and symptom severity, suggesting an involvement of mitochondrial dysfunction also in PTSD. Therefore, we examined number and composition of mitochondrial DNA before and after six weeks of inpatient psychotherapy treatment in a cohort of 60 female PTSD patients. We extracted DNA from isolated monocytes before and after inpatient treatment and quantified cellular mtDNA using multiplex qPCR. We hypothesized that treatment would lead to changes in cellular mtDNA levels and that change in mtDNA level would be associated with PTSD symptom severity and treatment response. It could be shown that mtDNA copy number and the ratio of variant mtDNA decreased during therapy, however, this change did not correlate with treatment response. Our results suggest that inpatient treatment can reduce signs of mitochondrial allostatic load, which could have beneficial effects on mental health. The quantification of mtDNA and the determination of cellular heteroplasmy could represent valuable biomarkers for the molecular characterization of mental disorders in the future.

Characterization of Dendritic Cell Metabolism by Flow Cytometry

In response to different stimuli, dendritic cells (DCs) undergo metabolic reprogramming to support their function. Here we describe how fluorescent dyes and antibody-based approaches can be used to assess various metabolic parameters of DCs including glycolysis, lipid metabolism, mitochondrial activity, and the activity of important sensors and regulators of cellular metabolism, mTOR and AMPK. These assays can be performed using standard flow cytometry and will allow for the determination of metabolic properties of DC populations at single-cell level and to characterize metabolic heterogeneity within them.

Time- and dose-dependent biological effects of a sub-chronic exposure to realistic doses of salicylic acid in the gills of mussel Mytilus galloprovincialis

Among nonsteroidal anti-inflammatory drugs (NSAIDs) commonly found in seawater and wastewater, salicylic acid (SA) represents one of the most persistent and hazardous compounds for aquatic organisms. This study was therefore designed to elucidate the biological effects of SA in mussel Mytilus galloprovincialis. During a sub-chronic exposure (12 days), mussels were exposed to five realistic concentrations of SA (C1: 0.05 μg/L; C2: 0.5 μg/L; C3: 5 μg/L; C4: 50 μg/L; C5: 100 μg/L) and gills, selected as the target organ, were collected at different time points (T3: 3 days; T5: 5 days; T12: 12 days). Exposure to SA induced no histological alterations in mussel gills, despite a relevant hemocyte infiltration was observed throughout the exposure as a defensive response to SA. Temporal modulation of glutathione S-transferase (GST), catalase (CAT), and superoxide dismutase (SOD) activities suggested the occurrence of antioxidant and detoxifying responses against SA exposure, while lipid peroxidation (LPO), except for a partial increase at T3, was prevented. Inhibition of the cholinergic system was also reported by reduced acetylcholinesterase (AChE) activity, mainly at T12. Overall, findings from this study contribute to enlarge the current knowledge on the cytotoxicity of SA, on non-target aquatic organisms, and might for the enhancement of new ecopharmacovigilance programs and optimization of the efficacy of wastewater treatment plants for mitigation of pharmaceutical pollution in coastal areas.

Mitochondrial Activity Is Upregulated in Nonlesional Atopic Dermatitis and Amenable to Therapeutic Intervention

Previous work has shown increased expression of genes related to oxidative stress in nonlesional atopic dermatitis (ADNL) skin. Although mitochondria are key regulators of ROS production, their function in AD has never been investigated. Energy metabolism and the oxidative stress response were studied in keratinocytes (KCs) from patients with ADNL or healthy controls. Moreover, ADNL human epidermal equivalents were treated with tigecycline or MitoQ. We found that pyruvate and glucose were used as energy substrates by ADNL KCs. Increased mitochondrial oxidation of (very) long-chain fatty acids, associated with enhanced complexes I and II activities, was observed in ADNL KCs. Metabolomic analysis revealed increased tricarboxylic acid cycle turnover. Increased aerobic metabolism generated oxidative stress in ADNL KCs. ADNL human epidermal equivalents displayed increased mitochondrial function and an enhanced oxidative stress response compared with controls. Treatment of ADNL human epidermal equivalents with tigecycline or MitoQ largely corrected the AD profile, including high p-65 NF-κB, abnormal lamellar bodies, and cellular damage. Furthermore, we found that glycolysis supports but does not supersede mitochondrial metabolism in ADNL KCs. Thus, aerobic metabolism predominates in ADNL but leads to oxidative stress. Therefore, mitochondria could be a reservoir of potential therapeutic targets in atopic dermatitis.

Zebrafish embryos as an in vivo model to investigate cisplatin-induced oxidative stress and apoptosis in mitochondrion-rich ionocytes

Pharmaceuticals and personal care products are emerging environmental pollutants. Cisplatin, one of the most widely used platinum-based chemotherapeutic agents, has been found to contaminate aquatic environments. Using zebrafish embryos as a model, cisplatin was previously found to impair skin ionocytes and ion regulation. The purpose of this study was to further investigate how cisplatin damages ionocytes. Zebrafish embryos were exposed to cisplatin (0, 50, and 100 μM) for 96 h (4-100 h post-fertilization) and then stained with fluorescent dyes to reveal mitochondrial activity (rhodamine123), apoptosis (acridine orange), and oxidative stress (CellROX/MitoSOX) in ionocytes of living embryos. Results showed that cisplatin exposure decreased rhodamine 123-labeled ionocytes, induced oxidative stress in ionocytes, and promoted apoptosis in a concentration-dependent manner. Quantitative PCR analysis showed that mRNA levels of antioxidative genes (sod1, sod2, gpx1a, and cat) and an apoptotic gene (caps3a) were induced. In the time-course experiment at 96-98 h post-fertilization, cisplatin increased oxidative stress and apoptosis in ionocytes in a time-dependent manner. In conclusion, this study demonstrates that cisplatin exposure induces oxidative stress, mitochondrial damage, and apoptosis in ionocytes of zebrafish embryos.

Surface-mediated high antioxidant and anti-inflammatory effects of astaxanthin-loaded ultrathin graphene oxide film that inhibits the overproduction of intracellular reactive oxygen species

Background

Astaxanthin (AST) is known as a powerful antioxidant that affects the removal of active oxygen and inhibits the production of lipid peroxide caused by ultraviolet light. However, it is easily decomposed by heat or light during production and storage because of the unsaturated compound nature with a structural double bond. The activity of AST can be reduced and lose its antioxidant capability. Graphene oxide (GO) is an ultrathin nanomaterial produced by oxidizing layered graphite. The chemical combination of AST with GO can improve the dispersion properties to maintain structural stability and antioxidant activity because of the tightly bonded functionalized GO surface.

Methods

Layered GO films were used as nanocarriers for the AST molecule, which was produced via flow-enabled self-assembly and subsequent controlled solution deposition of RGD peptide and AST molecules. Synthesis of the GO-AST complex was also carried out for the optimized concentration. The characterization of prepared materials was analyzed through transmission electron microscopy (TEM), scanning electron microscope (SEM), Fourier-transform infrared spectroscopy (FT-IR), atomic force microscope (AFM), and Raman spectroscopy. Antioxidant activity was tested by 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and 2.2-diphenyl-1-picrylhydrazyl (DPPH) assays. The antibacterial effect and antioxidant effects were monitored for the ultrathin GO/RGD/AST Film. Further, reactive oxygen species (ROS) assay was used to evaluate the anti-inflammatory effects on L-929 fibroblasts.

Results

Cotreatment of GO-AST solution demonstrated a high antioxidant combined effect with a high ABTS and DPPH radicals scavenging activity. The GO/RGD/AST film was produced by the self-assembly process exhibited excellent antibacterial effects based on physicochemical damage against E. coli and S. aureus. In addition, the GO/RGD/AST film inhibited H₂O₂-induced intracellular ROS, suppressed the toxicity of lipopolysaccharide (LPS)-induced cells, and restored it, thereby exhibiting strong antioxidant and anti-inflammatory effects.

Conclusion

As GO nanocarrier-assisted AST exerted promising antioxidant and antibacterial reactions, presented a new concept to expand basic research into the field of tissue engineering.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40824-022-00276-4.

A new mitochondrial probe combining pyrene and a triphenylphosphonium salt for cellular oxygen and free radical detection via fluorescence lifetime measurements

To improve and diversify the quantification of reactive oxygen species (ROS) in mitochondria of single cells, we connected pyrene derivatives (PB) to a triphenylphosphonium salt (TPP⁺) as a mitochondrial vector forming PB-TPP⁺ probes. Two pyrene isomers with the n-butyltriphenylphosphonium moieties attached at their 1- or 2- positions were synthesized and characterized. Using the long fluorescence lifetime of pyrene, it was possible to monitor the variation of cellular free radicals and oxygen and to follow the reversibility of both quenchers in real-time. We compared the behavior of these new probes to the previously published pyrene-probes, functionalized by a mitochondrial-penetrating peptide, allowing their transfer to the mitochondria (Mito-PB) or to the cytosolic membrane for pyrene butyric acid (PBA). The high cellular uptake of the new probes allows cells to be loaded with an initial concentration 40 times lower than that for Mito-PB probes, without inducing perturbations in cell growth. The variation in free radicals and oxygen levels was monitored within cells under different stress conditions through the fluorescence lifetime of the new TPP⁺-based probes giving comparable results to those obtained for MPP-based probes. However, at a loading concentration as low as 25 nM, our technique allows the detection of increased production of free radicals in the mitochondria in the presence of the TPP⁺ vector, a warning to the user of this well-known vector.

Transcription factor nuclear factor erythroid 2 p45-related factor 2 (NRF2) ameliorates sepsis-associated acute kidney injury by maintaining mitochondrial homeostasis and improving the mitochondrial function

Mitochondrial dysfunction has a role in sepsis-associated acute kidney injury (S-AKI), so the restoration of normal mitochondrial homeostasis may be an effective treatment strategy. Transcription factor nuclear factor erythroid 2 p45-related factor 2 (NRF2) is a main regulator of cell-redox homeostasis, and recent studies reported that NRF2 activation helped to preserve mitochondrial morphology and function under conditions of stress. However, the role of NRF2 in the process of S-AKI is still not well understood. The present study investigated whether NRF2 regulates mitochondrial homeostasis and influences mitochondrial function in S-AKI. We demonstrated activation of NRF2 in an in vitro model: lipopolysaccharide (LPS) challenge of ductal epithelial cells of rat renal tubules (NRK-52e cells), and an in vivo model: cecal ligation and puncture (CLP) of rats. Over-expression of NRF2 attenuated oxidative stress, apoptosis, and the inflammatory response; enhanced mitophagy and mitochondrial biogenesis; and mitigated mitochondrial damage in the in vitro model. In vivo experiments showed that rats treated with an NRF2 agonist had higher adenosine triphosphate (ATP) levels, lower blood urea nitrogen and creatinine levels, fewer renal histopathological changes, and higher expression of mitophagy-related proteins [PTEN-induced putative kinase 1 (PINK1), parkin RBR E3 ubiquitin protein ligase (PRKN), microtubule-associated protein 1 light chain 3 II (LC3 II)] and mitochondrial biogenesis-related proteins [peroxisome proliferator-activated receptor γ coactivator-1 (PGC-1α) and mitochondrial transcription factor A (TFAM)]. Electron microscopy of kidney tissues showed that mitochondrial damage was alleviated by treatment with an NRF2 agonist, and the opposite response occurred upon treatment with an NRF2 antagonist. Overall, our findings suggest that mitochondria have an important role in the pathogenesis of S-AKI, and that NRF2 activation restored mitochondrial homeostasis and function in the presence of this disease. This mitochondrial pathway has the potential to be a novel therapeutic target for the treatment of S-AKI.

Assessing Drug-Induced Mitochondrial Toxicity in Cardiomyocytes: Implications for Preclinical Cardiac Safety Evaluation

Drug-induced cardiotoxicity not only leads to the attrition of drugs during development, but also contributes to the high morbidity and mortality rates of cardiovascular diseases. Comprehensive testing for proarrhythmic risks of drugs has been applied in preclinical cardiac safety assessment for over 15 years. However, other mechanisms of cardiac toxicity have not received such attention. Of them, mitochondrial impairment is a common form of cardiotoxicity and is known to account for over half of cardiovascular adverse-event-related black box warnings imposed by the U.S. Food and Drug Administration. Although it has been studied in great depth, mitochondrial toxicity assessment has not yet been incorporated into routine safety tests for cardiotoxicity at the preclinical stage. This review discusses the main characteristics of mitochondria in cardiomyocytes, drug-induced mitochondrial toxicities, and high-throughput screening strategies for cardiomyocytes, as well as their proposed integration into preclinical safety pharmacology. We emphasize the advantages of using adult human primary cardiomyocytes for the evaluation of mitochondrial morphology and function, and the need for a novel cardiac safety testing platform integrating mitochondrial toxicity and proarrhythmic risk assessments in cardiac safety evaluation.

Prescription Drugs and Mitochondrial Metabolism

Mitochondria are central to the physiology and survival of nearly all eukaryotic cells and house diverse metabolic processes including oxidative phosphorylation, reactive oxygen species buffering, metabolite synthesis/exchange, and Ca2+ sequestration. Mitochondria are phenotypically heterogeneous and this variation is essential to the complexity of physiological function among cells, tissues, and organ systems. As a consequence of mitochondrial integration with so many physiological processes, small molecules that modulate mitochondrial metabolism induce complex systemic effects. In the case of many common prescribed drugs, these interactions may contribute to drug therapeutic mechanisms, induce adverse drug reactions, or both. The purpose of this article is to review historical and recent advances in the understanding of the effects of prescription drugs on mitochondrial metabolism. Specific 'modes' of xenobiotic-mitochondria interactions are discussed to provide a set of qualitative models that aid in conceptualizing how the mitochondrial energy transduction system may be affected. Findings of recent in vitro high-throughput screening studies are reviewed, and a few candidate drug classes are chosen for additional brief discussion (i.e. antihyperglycemics, antidepressants, antibiotics, and antihyperlipidemics). Finally, recent improvements in pharmacokinetic models that aid in quantifying systemic effects of drug-mitochondria interactions are briefly considered.

A new mitochondria-targeted fluorescent probe for exogenous and endogenous superoxide anion imaging in living cells and pneumonia tissue

Schematic illustration of in situ detection for superoxide anions by Mito-YX.

Oxidative Stress Is a Key Modulator in the Development of Nonalcoholic Fatty Liver Disease

Nonalcoholic fatty liver disease (NAFLD) is the most common chronic liver disease worldwide, and scientific studies consistently report that NAFLD development can be accelerated by oxidative stress. Oxidative stress can induce the progression of NAFLD to NASH by stimulating Kupffer cells, hepatic stellate cells, and hepatocytes. Therefore, studies are underway to identify the role of antioxidants in the treatment of NAFLD. In this review, we have summarized the origins of reactive oxygen species (ROS) in cells, the relationship between ROS and NAFLD, and have discussed the use of antioxidants as therapeutic agents for NAFLD.

Stress-responsive rhodamine bioconjugates for membrane-potential-independent mitochondrial live-cell imaging and tracking

The 'powerhouses' of cell, mitochondria have seen an upsurge of interest in investigations pertaining to the imaging and mapping of physiological processes. By utilizing sterol-modified rhodamine, we have performed the live-cell imaging of mitochondria without dependence on a membrane potential. The sterol probes are highly biocompatible, and they can track the mitochondrial live-cell dynamics in a background-free manner with improved brightness and impressive contrast. This is the first attempt to study the stress response using a direct fluorescence readout with bio-conjugates of rhodamine inside mitochondria. The results pave the way for developing different sterol markers for understanding cellular responses and function.

A Simple Route to the Complexation of Lutein with Reduced Graphene Oxide Nanocarriers and Antioxidant Protection Against Blue Light

BACKGROUND

The excellent physicochemical properties of graphene-based materials, including graphene oxide (GO) and reduced GO (rGO), offer significant technological potential as multifunctional nanomaterials in biomedical fields. Lutein is a type of carotenoid that forms human macular pigments in the retina, where it inhibits harmful blue light and contributes to the strengthening of the antioxidant defense of retinal pigment epithelium cells.

METHODS

Synthesis of the Lutein-rGO (Lu-rGO) complex was carried out for the optimized concentration. Then characterization of material was analyzed through ultraviolet-visible spectrophotometer (UV-Vis spectra), Fourier-transform infrared spectroscopy (FT-IR), Raman spectroscopy, x-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM). Antioxidant activity of Lu-rGO complex was measured by 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), 2.2-diphenyl-1-picrylhydrazyl (DPPH), glutathione (GSH) oxidation assay. Then, oxidative stress induction by blue light and analyzed intracellular reactive oxygen species (ROS).

RESULTS AND CONCLUSION

Based on the FT-IR measurement, the reduction efficiency defined by area was found to be 87.3%, the ID/IG ratio of 0.98 demonstrated by the Lu-rGO complex in the Raman spectrum was slightly higher than that of the original GO. The exhibited significant decrease in the peak intensities of the oxygen functional groups of the XPS spectra of the Lu-rGO complex was observed compared with the GO. In the TEM image for the Lu-rGO complex, folded and wrinkled nanostructures over the lutein-covered rGO surface were evidenced by tight molecular binding. The Lu-rGO complex provided superior DPPH and ABTS radical scavenging activity than GO and lutein alone, and the oxidation of GSH was suppressed. It was confirmed that the content of intracellular ROS and lysosomes, increased by blue light, was reduced after treatment with the Lu-rGO complex on ARPE-19 cells. In summary, graphene-based nanocarriers could function as preventative antioxidants during photochemical ROS generation based on the mechanism of antioxidant action.

Anti-Inflammatory Fibronectin-AgNP for Regulation of Biological Performance and Endothelial Differentiation Ability of Mesenchymal Stem Cells

The engineering of vascular regeneration still involves barriers that need to be conquered. In the current study, a novel nanocomposite comprising of fibronectin (denoted as FN) and a small amount of silver nanoparticles (AgNP, ~15.1, ~30.2 or ~75.5 ppm) was developed and its biological function and biocompatibility in Wharton's jelly-derived mesenchymal stem cells (MSCs) and rat models was investigated. The surface morphology as well as chemical composition for pure FN and the FN-AgNP nanocomposites incorporating various amounts of AgNP were firstly characterized by atomic force microscopy (AFM), UV-Visible spectroscopy (UV-Vis), and Fourier-transform infrared spectroscopy (FTIR). Among the nanocomposites, FN-AgNP with 30.2 ppm silver nanoparticles demonstrated the best biocompatibility as assessed through intracellular ROS production, proliferation of MSCs, and monocytes activation. The expression levels of pro-inflammatory cytokines, TNF-α, IL-1β, and IL-6, were also examined. FN-AgNP 30.2 ppm significantly inhibited pro-inflammatory cytokine expression compared to other materials, indicating superior performance of anti-immune response. Mechanistically, FN-AgNP 30.2 ppm significantly induced greater expression of vascular endothelial growth factor (VEGF) and stromal-cell derived factor-1 alpha (SDF-1α) and promoted the migration of MSCs through matrix metalloproteinase (MMP) signaling pathway. Besides, in vitro and in vivo studies indicated that FN-AgNP 30.2 ppm stimulated greater protein expressions of CD31 and von Willebrand Factor (vWF) as well as facilitated better endothelialization capacity than other materials. Furthermore, the histological tissue examination revealed the lowest capsule formation and collagen deposition in rat subcutaneous implantation of FN-AgNP 30.2 ppm. In conclusion, FN-AgNP nanocomposites may facilitate the migration and proliferation of MSCs, induce endothelial cell differentiation, and attenuate immune response. These finding also suggests that FN-AgNP may be a potential anti-inflammatory surface modification strategy for vascular biomaterials.

A Dual Fluorescence-Spin Label Probe for Visualization and Quantification of Target Molecules in Tissue by Multiplexed FLIM-EPR Spectroscopy

Simultaneous visualization and concentration quantification of molecules in biological tissue is an important though challenging goal. The advantages of fluorescence lifetime imaging microscopy (FLIM) for visualization, and electron paramagnetic resonance (EPR) spectroscopy for quantification are complementary. Their combination in a multiplexed approach promises a successful but ambitious strategy because of spin label-mediated fluorescence quenching. Here, we solved this problem and present the molecular design of a dual label (DL) compound comprising a highly fluorescent dye together with an EPR spin probe, which also renders the fluorescence lifetime to be concentration sensitive. The DL can easily be coupled to the biomolecule of choice, enabling in vivo and in vitro applications. This novel approach paves the way for elegant studies ranging from fundamental biological investigations to preclinical drug research, as shown in proof-of-principle penetration experiments in human skin ex vivo.

Effect of iron addition on mAb productivity and oxidative stress in Chinese hamster ovary culture

Trace metals play a critical role in the development of culture media used for the production of therapeutic proteins. Iron has been shown to enhance the productivity of monoclonal antibodies during Chinese hamster ovary (CHO) cell culture. However, the redox activity and pro-oxidant behavior of iron may also contribute toward the production of reactive oxygen species (ROS). In this work, we aim to clarify the influence of trace iron by examining the relationship between iron supplementation to culture media, mAb productivity and glycosylation, and oxidative stress interplay within the cell. Specifically, we assessed the impacts of iron supplementation on (a) mAb production and glycosylation; (b) mitochondria-generated free hydroxyl radicals (ROS); (c) the cells ability to store energy during oxidative phosphorylation; and (d) mitochondrial iron concentration. Upon the increase of iron at inoculation, CHO cells maintained a capacity to rebound from iron-induced viability lapses during exponential growth phase and improved mAb productivity and increased mAb galactosylation. Fluorescent labeling of the mitochondrial hydroxyl radical showed enhanced environments of oxidative stress upon iron supplementation. Additional labeling of active mitochondria indicated that, despite the enhanced production of ROS in the mitochondria, mitochondrial membrane potential was minimally impacted. By replicating iron treatments during seed train passaging, the CHO cells were observed to adapt to the shock of iron supplementation prior to inoculation. Results from these experiments demonstrate that CHO cells have the capacity to adapt to enhanced environments of oxidative stress and improve mAb productivity and mAb galactosylation with minimal perturbations to cell culture.

Quantum monitoring of cellular metabolic activities in single mitochondria

Free radicals play a vital role in all kinds of biological processes including immune responses. However, free radicals have short lifetimes and are highly reactive, making them difficult to measure using current methods. Here, we demonstrate that relaxometry measurement, or T1, inherited from the field of diamond magnetometry can be used to detect free radicals in living cells with subcellular resolution. This quantum sensing technique is based on defects in diamond, which convert a magnetic signal into an optical signal, allowing nanoscale magnetic resonance measurements. We functionalized fluorescent nanodiamonds (FNDs) to target single mitochondria within macrophage cells to detect the metabolic activity. In addition, we performed measurements on single isolated mitochondria. We were able to detect free radicals generated by individual mitochondria in either living cells or isolated mitochondria after stimulation or inhibition.

Comprehensive Review of Methodology to Detect Reactive Oxygen Species (ROS) in Mammalian Species and Establish Its Relationship with Antioxidants and Cancer

Evidence suggests that reactive oxygen species (ROS) mediate tissue homeostasis, cellular signaling, differentiation, and survival. ROS and antioxidants exert both beneficial and harmful effects on cancer. ROS at different concentrations exhibit different functions. This creates necessity to understand the relation between ROS, antioxidants, and cancer, and methods for detection of ROS. This review highlights various sources and types of ROS, their tumorigenic and tumor prevention effects; types of antioxidants, their tumorigenic and tumor prevention effects; and abnormal ROS detoxification in cancer; and methods to measure ROS. We conclude that improving genetic screening methods and bringing higher clarity in determination of enzymatic pathways and scale-up in cancer models profiling, using omics technology, would support in-depth understanding of antioxidant pathways and ROS complexities. Although numerous methods for ROS detection are developing very rapidly, yet further modifications are required to minimize the limitations associated with currently available methods.

The purinergic receptor P2Y11 choreographs the polarization, mitochondrial metabolism, and migration of T lymphocytes

T cells must migrate to encounter antigen-presenting cells and perform their roles in host defense. Here, we found that autocrine stimulation of the purinergic receptor P2Y11 regulates the migration of human CD4 T cells. P2Y11 receptors redistributed from the front to the back of polarized cells where they triggered intracellular cAMP/PKA signals that attenuated mitochondrial metabolism at the back. The absence of P2Y11 receptors at the front of cells resulted in hotspots of mitochondrial metabolism and localized ATP production that stimulated P2X4 receptors, Ca²⁺ influx, and pseudopod protrusion at the front. This regulatory function of P2Y11 receptors depended on their subcellular redistribution and autocrine stimulation by cellular ATP release and was perturbed by indiscriminate global stimulation. We conclude that excessive extracellular ATP-such as in response to inflammation, sepsis, and cancer-disrupts this autocrine feedback mechanism, which results in defective T cell migration, impaired T cell function, and loss of host immune defense.

Caernohabditis elegans as a Model Organism to Evaluate the Antioxidant Effects of Phytochemicals

The nematode Caenorhabditis elegans was introduced as a model organism in biological research by Sydney Brenner in the 1970s. Since then, it has been increasingly used for investigating processes such as ageing, oxidative stress, neurodegeneration, or inflammation, for which there is a high degree of homology between C. elegans and human pathways, so that the worm offers promising possibilities to study mechanisms of action and effects of phytochemicals of foods and plants. In this paper, the genes and pathways regulating oxidative stress in C. elegans are discussed, as well as the methodological approaches used for their evaluation in the worm. In particular, the following aspects are reviewed: the use of stress assays, determination of chemical and biochemical markers (e.g., ROS, carbonylated proteins, lipid peroxides or altered DNA), influence on gene expression and the employment of mutant worm strains, either carrying loss-of-function mutations or fluorescent reporters, such as the GFP.

In Vitro and In Vivo Electrochemical Measurement of Reactive Oxygen Species After Treatment with Anticancer Drugs

In vivo monitoring of reactive oxygen species (ROS) in tumors during treatment with anticancer therapy is important for understanding the mechanism of action and in the design of new anticancer drugs. In this work, a platinized nanoelectrode is placed into a single cell for detection of the ROS signal, and drug-induced ROS production is then recorded. The main advantages of this method are the short incubation time with the drug and its high sensitivity which allows the detection of low intracellular ROS concentrations. We have shown that our new method can measure the ROS response to chemotherapy in tumor-bearing mice in real-time. ROS levels were measured in vivo inside the tumor at different depths in response to doxorubicin. This work provides an effective new approach for the measurement of intracellular ROS by platinized nanoelectrodes.

High-content fluorescence imaging with the metabolic flux assay reveals insights into mitochondrial properties and functions

Metabolic flux technology with the Seahorse bioanalyzer has emerged as a standard technique in cellular metabolism studies, allowing for simultaneous kinetic measurements of respiration and glycolysis. Methods to extend the utility and versatility of the metabolic flux assay would undoubtedly have immediate and wide-reaching impacts. Herein, we describe a platform that couples the metabolic flux assay with high-content fluorescence imaging to simultaneously provide means for normalization of respiration data with cell number; analyze cell cycle distribution; and quantify mitochondrial content, fragmentation state, membrane potential, and mitochondrial reactive oxygen species. Integration of fluorescent dyes directly into the metabolic flux assay generates a more complete data set of mitochondrial features in a single assay. Moreover, application of this integrated strategy revealed insights into mitochondrial function following PGC1a and PRC1 inhibition in pancreatic cancer and demonstrated how the Rho-GTPases impact mitochondrial dynamics in breast cancer.

Design of Fluorescent Probes for Bioorthogonal Labeling of Carbonylation in Live Cells

With the rapid development of chemical biology, many diagnostic fluorophore-based tools were introduced to specific biomolecules by covalent binding. Bioorthogonal reactions have been widely utilized to manage challenges faced in clinical practice for early diagnosis and treatment of several tumor samples. Herein, we designed a small molecule fluorescent-based biosensor, 2Hydrazine-5nitrophenol (2Hzin5NP), which reacts with the carbonyl moiety of biomolecules through bioorthogonal reaction, therefore can be utilized for the detection of biomolecule carbonylation in various cancer cell lines. Our almost non-fluorescent chemical probe has a fast covalent binding with carbonyl moieties at neutral pH to form a stable fluorescent hydrazone product leading to a spectroscopic alteration in live cells. Microscopic and fluorometric analyses were used to distinguish the exogenous and endogenous ROS induced carbonylation profile in human dermal fibroblasts along with A498 primary site and ACHN metastatic site renal cell carcinoma (RRC) cell lines. Our results showed that carbonylation level that differs in response to exogenous and endogenous stress in healthy and cancer cells can be detected by the newly synthesized bioorthogonal fluorescent probe. Our results provide new insights into the development of novel bioorthogonal probes that can be utilized in site-specific carbonylation labeling to enhance new diagnostic approaches in cancer.

Priming with inflammatory cytokines is not a prerequisite to increase immune-suppressive effects and responsiveness of equine amniotic mesenchymal stromal cells

BACKGROUND

Equine amniotic mesenchymal stromal cells (AMSCs) and their conditioned medium (CM) were evaluated for their ability to inhibit in vitro proliferation of peripheral blood mononuclear cells (PBMCs) with and without priming. Additionally, AMSC immunogenicity was assessed by expression of MHCI and MHCII and their ability to counteract the in vitro inflammatory process.

METHODS

Horse PBMC proliferation was induced with phytohemagglutinin. AMSC priming was performed with 10 ng/ml of TNF-α, 100 ng/ml of IFN-γ, and a combination of 5 ng/ml of TNF-α and 50 ng/ml of IFN-γ. The CM generated from naïve unprimed and primed AMSCs was also tested to evaluate its effects on equine endometrial cells in an in vitro inflammatory model induced by LPS. Immunogenicity marker expression (MHCI and II) was evaluated by qRT-PCR and by flow cytometry.

RESULTS

Priming does not increase MHCI and II expression. Furthermore, the inhibition of PBMC proliferation was comparable between naïve and conditioned cells, with the exception of AMSCs primed with both TNF-α and IFN-γ that had a reduced capacity to inhibit T cell proliferation. However, AMSC viability was lower after priming than under other experimental conditions. CM from naïve and primed AMSCs strongly inhibited PBMC proliferation and counteracted the inflammatory process, rescuing about 65% of endometrial cells treated by LPS.

CONCLUSION

AMSCs and their CM have a strong capacity to inhibit PBMC proliferation, and priming is not necessary to improve their immunosuppressive activity or reactivity in an inflammatory in vitro model.

Polarizing Graphene Quantum Dots toward Long-Acting Intracellular Reactive Oxygen Species Evaluation and Tumor Detection

The evaluation of intracellular reactive oxygen species (ROS) would greatly deepen the understanding of cell metabolism/proliferation and tumor detection. However, current long-acting level tracking techniques for intracellular ROS remain unsuited to practical applications. To solve this problem, we synthesized cyclotriphosphazene-doped graphene quantum dots (C-GQDs) whose quantum yield is highly sensitive to ROS (increased by 400% from 0.12 to 0.63). Electron cloud polarization of oxidized cyclotriphosphazene rings in C-GQDs is confirmed to account for this novel optical property by density functional theory calculations and experimental results. In combination with excellent biological stability, C-GQDs achieve a long-acting evaluation of intracellular ROS level (more than 72 h) with an accuracy of 98.3%. In addition, recognition rates exceeding 90% are demonstrated to be feasible for eight kinds of tumor cell lines cultured with C-GQDs, which can also be expanded to in vivo detection. C-GQDs also show a high recognition rate (82.33%) and sensitivity (79.65%) for tumor cells in blood samples.

Effects of CO2 on the transformation of antibiotic resistance genes via increasing cell membrane channels

The increase of CO₂ concentration in the atmosphere, water and soil environment can lead to the changes in microbial activities. However, the transformation of antibiotic resistance genes has not been investigated in the presence of higher levels of CO₂. This study demonstrated that CO₂ facilitated the transformation of pUC19 plasmid, carrying ampicillin resistance genes, into Escherichia coli. Mechanism studies revealed that the type Ⅱ secretion system, type Ⅳ pilus and some other secretion systems were enhanced by CO₂, leading to DNA capture by pilus, larger cell pore sizes and more cell membrane channels. CO₂ also increased reactive oxygen species production, leading to SOS response and cell membrane damage. Besides, changes in intracellular Fe²⁺ and Mg²⁺ concentrations induced by CO₂ caused greater damage to the cell membrane and enhanced secretion systems, respectively. Overall, increased CO₂ provided more cell membrane channels for plasmid uptake and led to higher transformation efficiencies. The potential risk of a natural factor on the transformation of ARGs was first studied in this study, which helps us understand the fate of ARGs in ecosystems. As the carbon emission will continue to grow and enhance the enrichment of CO₂ in water and soil, the findings revealed a more severe public health issue under the background of carbon emission and CO₂ leakage.

The Role of Mitochondria in the Mechanisms of Cardiac Ischemia-Reperfusion Injury

Mitochondria play a critical role in maintaining cellular function by ATP production. They are also a source of reactive oxygen species (ROS) and proapoptotic factors. The role of mitochondria has been established in many aspects of cell physiology/pathophysiology, including cell signaling. Mitochondria may deteriorate under various pathological conditions, including ischemia-reperfusion (IR) injury. Mitochondrial injury can be one of the main causes for cardiac and other tissue injuries by energy stress and overproduction of toxic reactive oxygen species, leading to oxidative stress, elevated calcium and apoptotic and necrotic cell death. However, the interplay among these processes in normal and pathological conditions is still poorly understood. Mitochondria play a critical role in cardiac IR injury, where they are directly involved in several pathophysiological mechanisms. We also discuss the role of mitochondria in the context of mitochondrial dynamics, specializations and heterogeneity. Also, we wanted to stress the existence of morphologically and functionally different mitochondrial subpopulations in the heart that may have different sensitivities to diseases and IR injury. Therefore, various cardioprotective interventions that modulate mitochondrial stability, dynamics and turnover, including various pharmacologic agents, specific mitochondrial antioxidants and uncouplers, and ischemic preconditioning can be considered as the main strategies to protect mitochondrial and cardiovascular function and thus enhance longevity.

Anti-Oxidant Activity of Gallotannin-Enriched Extract of Galla Rhois Can Associate with the Protection of the Cognitive Impairment through the Regulation of BDNF Signaling Pathway and Neuronal Cell Function in the Scopolamine-Treated ICR Mice

The antibacterial, anti-inflammatory, anti-metastatic/anti-invasion activities and laxative activity of Galla Rhois (GR) are well-known, although the neuropreservation effects of their extracts are still to be elucidated. To investigate the novel therapeutic effects and molecular mechanism of GR on alleviation of cognitive impairment, two different dosages of gallotannin-enriched GR (GEGR) were administered to Korl:ICR mice for three weeks, and to induce memory impairment, scopolamine (SP) was administered during the last seven days of the GEGR treatment period. GEGR showed the high level of the free radical scavenging activity to DPPH and suppressive activity to reactive oxygen species (ROS) in B35 cells as well as enhanced SOD and CAT activity in brains of the SP-induced model. Latency time for memory impairment assessed by the passive avoidance test significantly protected in the SP+GEGR treated group as compared to the SP+Vehicle treated group. Moreover, similar protective effects were observed on the secretion of BDNF in SP+GEGR treated mice. The expression of TrkB receptor, and phosphorylation of PI3K on the TrkB receptor signaling pathway were dramatically protected in the SP-induced model after GEGR treatment, whereas the expression of p75^NTR receptor, the phosphorylation of JNK, and expression of Bax/Bcl-2 on the p75^NTR receptor signaling pathway was significantly protected in the same group. Furthermore, the GEGR treated SP-induced model showed decreased number of dead neural cells and suppressed acetylcholine esterase (AChE) activity and inhibited inflammatory responses. Taken together, these results indicate that the anti-oxidant activity of GEGR contributes to improving the neuronal cell function and survival during cognitive impairment in the SP-induced model through regulation of BDNF secretion and their receptor signaling pathway.

A New Approach in Cancer Treatment: Discovery of Chlorido[N,N'-disalicylidene-1,2-phenylenediamine]iron(III) Complexes as Ferroptosis Inducers

Chlorido[N,N'-disalicylidene-1,2-phenylenediamine]iron(III) complexes generate lipid-based ROS and induce ferroptosis in leukemia and neuroblastoma cell lines. The extent of ferroptosis on the mode of action is regulated by simple modifications of the substituents at the 1,2-phenylenediamine moiety. In HL-60 cells, the unsubstituted lead exclusively caused ferroptosis. For instance, a 4-F substituent shifted the mode of action toward both ferroptosis and necroptosis, while the analogously chlorinated derivative exerted only necroptosis. Remarkably, cell-death in NB1 neuroblastoma cells was solely induced by ferroptosis, independent of the used substituents. The effects were higher than that of the therapeutically applied drug cisplatin. These data clearly demonstrate for the first time that not only iron ions but also iron salophene complexes are potent ferroptosis inducers, which can be optimized as antitumor agents.

Enhanced superoxide sensitivity in organic field-effect transistor sensors by introducing nanoclay-polyphenol-polymer hybrid sensing channels

Here we report that nanoclay-polyphenol-polymer hybrid sensing channels can greatly enhance the sensitivity for hazardous reactive oxygen species (ROS) in organic field-effect transistor (OFET) sensors. The hybrid layers were prepared by introducing nanoclay into the binary mixtures of poly(3-hexylthiophene) (P3HT) and rutin (a polyphenol) at various weight ratios. The presence of nanoclay improved the P3HT crystallinity in the hybrid films, which contributed to the increased drain current and well-maintained hole mobility even at the reduced amount of charge-transporting P3HT part. At the best composition (P3HT:rutin:nanocaly = 10:1:2 by weight), the OFETs with the hybrid layers were able to sense even 1 nM superoxide (a ROS) and exhibited pronouncedly enhanced sensitivity compared to those without nanoclay. The morphology investigation disclosed that rutin-nanoclay complexes formed in the hybrid films might be responsible for the enhanced sensitivity, because they let more rutin molecules protrude on the surface of channel layers for reactions with superoxide.

Initial biological evaluations of 18F-KS1, a novel ascorbate derivative to image oxidative stress in cancer

BACKGROUND

Reactive oxygen species (ROS)-induced oxidative stress damages many cellular components such as fatty acids, DNA, and proteins. This damage is implicated in many disease pathologies including cancer and neurodegenerative and cardiovascular diseases. Antioxidants like ascorbate (vitamin C, ascorbic acid) have been shown to protect against the deleterious effects of oxidative stress in patients with cancer. In contrast, other data indicate potential tumor-promoting activity of antioxidants, demonstrating a potential temporal benefit of ROS. However, quantifying real-time tumor ROS is currently not feasible, since there is no way to directly probe global tumor ROS. In order to study this ROS-induced damage and design novel therapeutics to prevent its sequelae, the quantitative nature of positron emission tomography (PET) can be harnessed to measure in vivo concentrations of ROS. Therefore, our goal is to develop a novel translational ascorbate-based probe to image ROS in cancer in vivo using noninvasive PET imaging of tumor tissue. The real-time evaluations of ROS state can prove critical in developing new therapies and stratifying patients to therapies that are affected by tumor ROS.

METHODS

We designed, synthesized, and characterized a novel ascorbate derivative (E)-5-(2-chloroethylidene)-3-((4-(2-fluoroethoxy)benzyl)oxy)-4-hydroxyfuran-2(5H)-one (KS1). We used KS1 in an in vitro ROS MitoSOX-based assay in two different head and neck squamous cancer cells (HNSCC) that express different ROS levels, with ascorbate as reference standard. We radiolabeled 18F-KS1 following 18F-based nucleophilic substitution reactions and determined in vitro reactivity and specificity of 18F-KS1 in HNSCC and prostate cancer (PCa) cells. MicroPET imaging and standard biodistribution studies of 18F-KS1 were performed in mice bearing PCa cells. To further demonstrate specificity, we performed microPET blocking experiments using nonradioactive KS1 as a blocker.

RESULTS

KS1 was synthesized and characterized using 1H NMR spectra. MitoSOX assay demonstrated good correlations between increasing concentrations of KS1 and ascorbate and increased reactivity in SCC-61 cells (with high ROS levels) versus rSCC-61cells (with low ROS levels). 18F-KS1 was radiolabeled with high radiochemical purity (> 94%) and specific activity (~ 100 GBq/μmol) at end of synthesis (EOS). Cell uptake of 18F-KS1 was high in both types of cancer cells, and the uptake was significantly blocked by nonradioactive KS1, and the ROS blocker, superoxide dismutase (SOD) demonstrating specificity. Furthermore, 18F-KS1 uptake was increased in PCa cells under hypoxic conditions, which have been shown to generate high ROS. Initial in vivo tumor uptake studies in PCa tumor-bearing mice demonstrated that 18F-KS1 specifically bound to tumor, which was significantly blocked (threefold) by pre-injecting unlabeled KS1. Furthermore, biodistribution studies in the same tumor-bearing mice showed high tumor to muscle (target to nontarget) ratios.

CONCLUSION

This work demonstrates the strong preliminary support of 18F-KS1, both in vitro and in vivo for imaging ROS in cancer. If successful, this work will provide a new paradigm to directly probe real-time oxidative stress levels in vivo. Our work could enhance precision medicine approaches to treat cancer, as well as neurodegenerative and cardiovascular diseases affected by ROS.

PDK4 Augments ER-Mitochondria Contact to Dampen Skeletal Muscle Insulin Signaling During Obesity

Mitochondria-associated endoplasmic reticulum membrane (MAM) is a structural link between mitochondria and endoplasmic reticulum (ER). MAM regulates Ca2+ transport from the ER to mitochondria via an IP3R1-GRP75-VDAC1 complex-dependent mechanism. Excessive MAM formation may cause mitochondrial Ca2+ overload and mitochondrial dysfunction. However, the exact implication of MAM formation in metabolic syndromes remains debatable. Here, we demonstrate that PDK4 interacts with and stabilizes the IP3R1-GRP75-VDAC1 complex at the MAM interface. Obesity-induced increase in PDK4 activity augments MAM formation and suppresses insulin signaling. Conversely, PDK4 inhibition dampens MAM formation and improves insulin signaling by preventing MAM-induced mitochondrial Ca2+ accumulation, mitochondrial dysfunction, and ER stress. Furthermore, Pdk4-/- mice exhibit reduced MAM formation and are protected against diet-induced skeletal muscle insulin resistance. Finally, forced formation and stabilization of MAMs with synthetic ER-mitochondria linker prevented the beneficial effects of PDK4 deficiency on insulin signaling. Overall, our findings demonstrate a critical mediatory role of PDK4 in the development of skeletal muscle insulin resistance via enhancement of MAM formation.

Uncoupling Effect of F16 Is Responsible for Its Mitochondrial Toxicity and Anticancer Activity

As a novel delocalized lipophilic cation, F16 selectively accumulates in mitochondria of carcinoma cells and shows a broad spectrum of antiproliferative action towards cancer cell lines. In order to reveal the mode of action and molecular mechanism of F16 inducing cytotoxicity, we investigated the effects of F16 on cancer cells and isolated mitochondria relative to its precursor compound (E)-3-(2-(pyridine-4yl)vinyl)-1 H-indole (PVI), which has a similar structure without positive charge. It was found that PVI did not accumulate in mitochondria, and exhibited lower cytotoxicity compared to F16. However, when they were directly incubated with mitochondria, both F16 and PVI were observed to induce damage to mitochondrial structure and function. Moreover, it was found that F16 as well as PVI acted as uncouplers on mitochondria, and further rescue experiments revealed that the addition of adenosine 5'-triphosphate was the most effective way to recover the cell viability decreased by F16. Thus it was concluded that the decreased intracellular adenosine 5'-triphosphate availability induced by the uncoupling effect of F16 was a major factor in F16-mediated cytotoxicity. Futhermore, the results indicated that the uncoupling effect of F16 is attributed to its chemical stucture in common with PVI but independent of its positive charge. The study may shed light on understanding the underlying mechanism of action for F16, and providing suggestions for the design of new mitochondria-targeted antitumor molecules.

A graphene gold nanocomposite-based 5-FU drug and the enhancement of the MCF-7 cell line treatment

There is no doubt that cancer is now one of the most formidable diseases in the world; despite all the efforts and research, common treatment routes, including chemotherapy, photodynamic therapy, and photothermal therapy, suffer from different limitations in terms of their efficiency and performance. For this reason, different strategies are being explored to improve the efficiency of the traditional drugs reported to date. In this study, we have redirected the function of one of these drugs (5-fluorouracil, 5-FU) by combining it with a graphene–gold nanocomposite in different molar ratios that has been exceedingly used for biological research development. The high activity of the graphene–gold material enables it to produce reactive oxygen and ions, which display good anticancer and antioxidant activity through the scavenging of the DPPH, SOD and GP_x radicals; in addition, different characterizations have been used to confirm the structure and morphology of the obtained samples. Highly potent cytotoxicity against the MCF-7 cells was achieved with the drug combination containing the nanocomposite. All the results, including those obtained via cytometry, indicate that the combination of 5% graphene–gold nanocomposites with 5-FU exhibits a higher antitumor impact and more drug stability than pure 5-FU.

Graphene–gold nanocomposite materials combined with (5-fluorouracil, 5-FU) drug show high potent cytotoxicity against MCF-7 cells, can decrease HER-2 gene expression and cause cell cycle arrest.