Delivery Of Reactive Oxygen Species Research Articles

The structure and function of mitochondria-associated endoplasmic reticulum membranes and their role in pancreatic β-cells dysregulation

Membrane trafficking and organelle contact sites are important for regulating cell metabolism and survival. The highly specialized regions of close contacts between mitochondria and endoplasmic reticulum (ER), called mitochondria associated membranes (MAMs), are crucial signaling hubs for the lipid and calcium homeostasis, reactive oxygen species delivery, regulation of autophagy and mitochondrial dynamics. In recent years, MAMs have been the focus of multiple studies for identifying the MAMs proteins and defining their signaling mechanisms. Many studies have proved the importance of MAMs in maintaining the normal function of both organelles. Excessive MAM formation is known to trigger the cascade of pathological events, such as mitochondria calcium overload, aberrant lipid levels, autophagosome formation, and eventually, cell apoptosis. In this article, we focus on the composition and function of MAMs, more specifically, the role of MAMs in Ca2+ uptake, ER stress, mitochondrial fusion and fission and autophagy. The altered interaction between ER and mitochondria results in the amendment of pancreatic tissues, revealing the role of MAMs in glucose homeostasis and the development of diabetes. The development of mitochondrial dysfunction, ER stress and oxidative stress are co-related with β-cell dysfunction. MAMs are likely to play an important role of the functional state regulation in pancreatic cells under pathologies by regulating the signaling of the two organelles and the crosstalk of the two pathological events. It was found that under streptozotocin-induced diabetes, the increased level of mitophagy in pancreatic tissue is connected with tight junctions of MAMs.

Comparative evaluation on clinical efficacy of active oxygen toothpaste with herbal toothpaste in supragingival plaque reduction among gingivitis patients: A randomized controlled trial

Context: Gingivitis is a soft-tissue inflammation of the gingiva. It is initiated in the oral cavity by the accumulation of plaque. Among the various plaque control methods, dentifrices play a major role to reduce the microbial load in gingivitis patients. Herbal dentifrice reduces plaque levels and gingival inflammation. In a revolutionary process on dentifrice, BlueM (BM) International has recently introduced the BM dentifrice. Its mechanism of action is to reduce inflammation by controlled delivery of reactive oxygen species to injury sites. Aims: The aim of this study was to compare the clinical efficacy of two commercially available toothpaste, BM, and Dabur Red (DR) in gingivitis patients. Settings and Design: To compare the anti-plaque and anti-gingivitis efficacy of two commercially available toothpaste by measuring gingival, plaque, and bleeding indices in gingivitis patients. Subjects and Methods: A total of 45 patients with chronic gingivitis were included in the study. After oral prophylaxis, they were divided into three groups: Group A, Group B, and Group C who received BM toothpaste, DR toothpaste, and placebo toothpaste, respectively. The clinical parameters were recorded at baseline, 1st, 2nd, and 3rd weeks. Statistical Analysis Used: Data on the gingival index (GI) and plaque index (PI) and bleeding index (BI) were statistically analyzed by the mean and standard deviation between the groups using analysis of variance with Statistical Package for the Social Sciences software (SPSS version 20.0) with a 95% confidence level (P < 0.05). Results: The three groups showed significant reduction (P < 0.05) in PI, GI, and BI from baseline. The BM has more significant mean PI and BI than DR. Conclusions: This study demonstrated that active oxygen toothpaste has comparable anti-plaque and anti-gingivitis efficacies with herbal toothpaste (DR).

Modulation of ROS in nanosecond-pulsed plasma-activated media for dosage-dependent cancer cell inactivation in vitro

Dosage control of reactive oxygen and nitrogen species (RONS) is critical to low-temperature plasma applications in cancer therapy. Production of RONS by atmospheric pressure, nonequilibrium plasmas in contact with liquid may be modulated via plasma conditions including plasma treatment time and pulse voltage and repetition frequency. In this study, a terephthalic acid-based probe was used to measure hydroxyl radicals [OH(aq)] in water exposed to plasma and to demonstrate that the OH(aq) concentration increases linearly with treatment time. Fluorometric measurements of hydrogen peroxide concentration in plasma-activated water show a linear relationship between the H2O2 production rate and the pulse repetition frequency of the plasma. In vitro plasma treatment of cancer cells shows that pancreatic (Pan02) and breast (4T1-Luc) cancer cells have different sensitivities to plasma exposure. The dependence of Pan02 cell viability on plasma treatment time or pulse voltage is nonlinear. The system described here for generation and delivery of reactive oxygen species from a nanosecond pulsed plasma jet represents a promising alternative approach to cancer therapy.

Organic thin film photofaradaic pixels for on-demand electrochemistry in physiological conditions.

We report ultrathin organic photovoltaic elements optimized to run photofaradaic reactions in biological conditions. We demonstrate concurrent oxygen reduction to hydrogen peroxide and glucose oxidation. The devices are powered by deep-red irradiation in the tissue transparency window. We utilize bilayers of phthalocyanine, acting as the light absorber, and perylene diimide, functioning as both electron-acceptor and the hydrogen peroxide evolution electrocatalyst. These heterojunction bilayers are stable when irradiated in simulated physiological conditions, producing photovoltages sufficient to simultaneously drive cathodic oxygen reduction to H2O2 and anodic oxidation of glucose. We find that optimization of the anode metal is critical for sustained photofaradaic reactivity. Our results demonstrate a robust "wet" thin film photovoltaic with potential for physiological applications where localized electrochemical manipulation is desired, in particular the delivery of reactive oxygen species.

Oxidation kinetics of supersonic atmospheric plasma spraying ytterbium oxide doped molybdenum silicide coating

Rare earth oxides usually play an active role in modifying the microstructure and oxidation resistance of silicide coatings, but its modification mechanism has not yet been clarified. In this work, molybdenum silicide (MoSi2) coating with different contents of ytterbium oxide (Yb2O3) was fabricated using supersonic atmospheric plasma spraying, and its microstructural evolution and oxidation behavior were investigated. Experimental results shown that the morphological characteristics of produced SiO2-rich glass scale varied with the doping of Yb2O3, which noticeably affected the oxidation resistance of sprayed MoSi2-Yb2O3 coatings. All coated specimens exhibited a parabolic oxidation behavior, wherein the MoSi2-10 wt%Yb2O3 coating possessed the smallest parabolic constant and the lowest specific mass loss with 100 h oxidation at 1500 °C due to the absence of SiC-depleted region and the formation of continuous multicomponent compound scale. Given this, Yb2O3 additive with proper concentration not only guaranteed the sufficient filling of open spaces in SiO2 network by Yb3+ cations, but also strengthened the Si–O bonds to increasing the viscosity of SiO2 glass, thereby delaying the effective delivery of reactive oxygen species inwardly.

Construction and evaluation of tumor nucleus-targeting nanocomposite for cancer dual-mode imaging – Guiding photodynamic therapy/photothermal therapy

To tackle the barrier of the insufficient intra-cellular delivery of reactive oxygen species (ROS) and heat, we designed a multifunctional nanoplatform to release ROS and heat directly in the cell nucleus for enhancing combined photodynamic therapy (PDT) and photothermal therapy (PTT) of tumors. As a photothermal agent, WS2 nanoparticles were adsorbed photosensitive Au25(Captopril)18− (Au25) nanoclusters via electrostatic interaction. And Dexamethasone (Dex), a glucocorticoid with nucleus targeting capability, played a key role in the intra-nuclear process of heat and ROS. PTT can increase intra-tumoral blood flow to promote Au25 produce more ROS for PDT. Under near infrared (NIR) laser irradiation at a single 808 nm, these nucleus targeting WS2 nanoplatforms showed a significant decreased cell viability of 18.2 ± 1.7% and a high DNA damage degree of 59.6 ± 8.3%. Furthermore, the WS2 nanoplatform could be further used for X-ray computed tomography (CT) images. Taken together, our study provided a new prospect for effectively diagnostic and enhancing PTT/PDT efficacy.

How membrane lipids influence plasma delivery of reactive oxygen species into cells and subsequent DNA damage: an experimental and computational study.

The mechanisms of plasma in medicine are broadly attributed to plasma-derived reactive oxygen and nitrogen species (RONS). In order to exert any intracellular effects, these plasma-derived RONS must first traverse a major barrier in the cell membrane. The cell membrane lipid composition, and thereby the magnitude of this barrier, is highly variable between cells depending on type and state (e.g. it is widely accepted that healthy and cancerous cells have different membrane lipid compositions). In this study, we investigate how plasma-derived RONS interactions with lipid membrane components can potentially be exploited in the future for treatment of diseases. We couple phospholipid vesicle experiments, used as simple cell models, with molecular dynamics (MD) simulations of the lipid membrane to provide new insights into how the interplay between phospholipids and cholesterol may influence the response of healthy and diseased cell membranes to plasma-derived RONS. We focus on the (i) lipid tail saturation degree, (ii) lipid head group type, and (iii) membrane cholesterol fraction. Using encapsulated molecular probes, we study the influence of the above membrane components on the ingress of RONS into the vesicles, and subsequent DNA damage. Our results indicate that all of the above membrane components can enhance or suppress RONS uptake, depending on their relative concentration within the membrane. Further, we show that higher RONS uptake into the vesicles does not always correlate with increased DNA damage, which is attributed to ROS reactivity and lifetime. The MD simulations indicate the multifactorial chemical and physical processes at play, including (i) lipid oxidation, (ii) lipid packing, and (iii) lipid rafts formation. The methods and findings presented here provide a platform of knowledge that could be leveraged in the development of therapies relying on the action of plasma, in which the cell membrane and oxidative stress response in cells is targeted.

Perspective: Mitochondria-ER Contacts in Metabolic Cellular Stress Assessed by Microscopy.

The interplay of mitochondria with the endoplasmic reticulum and their connections, called mitochondria-ER contacts (MERCs) or mitochondria-associated ER membranes (MAMs), are crucial hubs in cellular stress. These sites are essential for the passage of calcium ions, reactive oxygen species delivery, the sorting of lipids in whole-body metabolism. In this perspective article, we focus on microscopic evidences of the pivotal role of MERCs/MAMs and their changes in metabolic diseases, like obesity, diabetes, and neurodegeneration.

The hormesis effect of plasma-elevated intracellular ROS on HaCaT cells

We have examined the link between ionized-gas plasma delivery of reactive oxygen species (ROS) to immortalized keratinocyte (HaCaT) cells and cell fate, defined in terms of cell viability versus death. Phospholipid vesicles were used as cell mimics to measure the possible intracellular ROS concentration, [ROSi], delivered by various plasma treatments. Cells were exposed to a helium cold atmospheric plasma (CAP) jet for different plasma exposure times (5–60 s) and gas flow rates (50–1000 ml min−1). Based upon the [ROSi] data we argue that plasma-generated ROS in the cell culture medium can readily diffuse into real cells. Plasma exposure that equated to an [ROSi] in the range of 3.81 × 10−10–9.47 × 10−8 M, measured at 1 h after the plasma exposure, resulted in increased cell viability at 72 h; whereas a higher [ROSi] at 1 h decreased cell viability after 72 h of culture. This may be because of the manner in which the ROS are delivered by the plasma: HaCaT cells better tolerate a low ROS flux over an extended plasma exposure period of 1 min, compared to a high flux delivered in a few seconds, although the final [ROSi] may be the same. Our results suggest that plasma stimulation of HaCaT cells follows the principle of hormesis.

Ionized gas (plasma) delivery of reactive oxygen species (ROS) into artificial cells

This study was designed to enhance our understanding of how reactive oxygen species (ROS), generated ex situ by ionized gas (plasma), can affect the regulation of signalling processes within cells. A model system, comprising of a suspension of phospholipid vesicles (cell mimics) encapsulating a ROS reporter, was developed to study the plasma delivery of ROS into cells. For the first time it was shown that plasma unequivocally delivers ROS into cells over a sustained period and without compromising cell membrane integrity. An important consideration in cell and biological assays is the presence of serum, which significantly reduced the transfer efficiency of ROS into the vesicles. These results are key to understanding how plasma treatments can be tailored for specific medical or biotechnology applications. Further, the phospholipid vesicle ROS reporter system may find use in other studies involving the application of free radicals in biology and medicine.

A ‘tissue model’ to study the plasma delivery of reactive oxygen species

We demonstrate the utility of a ‘tissue model’ to monitor the delivery of plasma jet-generated reactive oxygen species (ROS). We report on helium plasma jet interactions both across the surface and into the subsurface (defined as 150 µm to 1.5 mm) of the tissue model. The model comprises a gelatin gel encapsulating a homogeneously dispersed chemical or biological reporter molecule. Jet–surface interactions result in (i) star shaped patterns that resemble those previously reported for surface-plasma streamers on insulators (as imaged by Pockels sensing) and (ii) ‘filled’ or hollow circular surface features, which resemble the ‘killing’ patterns seen in plasma jet treatments of bacterial lawns.The use of reporter molecules show that plasma can deliver ROS from 150 µm to 1.5 mm below the tissue surface. Subsurface delivery of ROS is consistent with the use of plasma to decontaminate wounds (covered by wound exudate and clotted blood), the deactivation of whole biofilms, plasma-enhanced drug delivery through skin and the destruction of solid tumours.From the data presented, we argue that in these four cases (and others) ROS may be capable of directly accessing a tissue's subsurface, as opposed to other proposed mechanisms, which involve stimulating surface reactions that trigger a cascade of biomolecular signalling events (into the tissue).

Zinc Protoporphyrin Polymeric Nanoparticles: Potent Heme Oxygenase Inhibitor for Cancer Therapy

Oxidation therapy is an antitumor strategy in which, apoptosis or necrosis is caused by either excess delivery of reactive oxygen species (ROS) as an oxidant or anti-oxidant inhibition. Heme oxygenase (HO) is an anti-oxidant enzyme that plays an important role in cell growth and proliferation. The purpose of this study was to prepare poly lactic-co-glycolic acid (PLGA) nanoparticles (NPs) loaded with zinc protoporphyrin (ZnPP) to deliver the HO inhibitor into tumor. PLGA NPs were prepared using nanoprecipitation technique and their characteristics were optimized by Box-Behnken experimental design. Scanning electron microscopy and in vitro studies consisting of drug release, HO inhibitory effect, cytotoxicity and cellular uptake followed by in vivo biodistribution and blood cytotoxicity were carried out. Internalization of coumerin-6 loaded NPs by PC3 cells was visualized by confocal laser scanning microscopy beside quantitatively analysis. NPs average size, entrapment efficiency and drug loading were 100.12 ± 5.345nm, 55.6% ± 2.49 and 7.98% ± 0.341 respectively. Equal HO inhibitory effect of NPs compared to free ZnPP was observed. The IC50 value of ZnPP-NPs for PC3 human prostate cancer cells was found to be 2.14 ± 0.083μM. In conclusion, ZnPP loaded PLGA NPs could exhibit enough HO inhibitory effect against cancer cells to be considered as a promising candidate for cancer treatment investigation.

Characterization of a Microsphere Formulation Containing Glucose Oxidase and its In Vivo Efficacy in a Murine Solid Tumor Model

This work focused on the characterization and in vitro/in vivo evaluation of an alginate/chitosan microsphere (ACMS) formulation of glucose oxidase (GOX) for the locoregional delivery of reactive oxygen species for the treatment of solid tumors. The GOX distribution and ACMS composition were determined by confocal laser scanning microscopy and X-ray photoelectron spectroscopy. The mechanism of GOX loading and GOX-polymer interactions were examined with Fourier transform infrared spectroscopy and differential scanning calorimetry. In vitro cytotoxicity and in vivo efficacy of GOX-encapsulated ACMS (ACMS-GOX) were evaluated in EMT6 breast cancer cells and solid tumors. GOX was loaded into calcium alginate (CaAlg) gel beads via electrostatic interaction and the CaAlg-GOX-chitosan complexation likely stabilized GOX. Higher concentrations of GOX near the surface of ACMS were detected. GOX retained its integrity upon adsorption to CaAlg gel beads during the coating and after release from ACMS. ACMS-GOX exhibited cytotoxicity to the breast cancer cells in vitro and their efficacy increased with increasing incubation time. Intratumorally delivered ACMS-GOX significantly delayed tumor growth with much lower general toxicity than free GOX. The results suggest that the ACMS-GOX formulation has the potential for the intratumoral delivery of therapeutic proteins to treat solid tumors.