Mitochondrial and nonmitochondrial reduction of MTT: interaction of MTT with TMRE, JC-1, and NAO mitochondrial fluorescent probes

Facile Synthesis of a Multifunctional Porous Organic Polymer Nanosonosensitizer (mHM@HMME) for Enhanced Cancer Sonodynamic Therapy

Sonodynamic therapy (SDT), which involves the activation of sonosensitizers to generate cytotoxic reactive oxygen species under ultrasound irradiation, is a promising noninvasive modality for cancer treatment. However, the clinical translational application of SDT is impeded by the lack of efficient sonosensitizers, the inefficient accumulation of sonosensitizers at tumor sites, and the complicated immunosuppressive tumor microenvironment. Herein, we developed a facilely synthesized multifunctional porous organic polymer nanosonosensitizer (mHM@HMME) for enhanced SDT. Specifically, mHM@HMME nanosonosensitizers were prepared by incorporating chemotherapeutic mitoxantrone into the one-step synthesis process of disulfide bond containing porous organic polymers, followed by loading with organic sonosensitizer (HMME) and camouflaging with a cancer cell membrane. Due to the cancer cell membrane camouflage, this multifunctional mHM@HMME nanosonosensitizer showed prolonged blood circulation and tumor targeting aggregation. Under ultrasound irradiation, the mHM@HMME nanosonosensitizer exhibited a satisfactory SDT performance both in vitro and in vivo. Moreover, the potent SDT combined with glutathione-responsive drug release in tumor cells induced robust immunogenic cell death to enhance the antitumor effect of SDT in turn. Overall, this facilely synthesized multifunctional mHM@HMME nanosonosensitizer shows great potential application in enhanced SDT.

Effects of an indole derivative on cell proliferation, transfection, and alternative splicing in production of lentiviral vectors by transient co-transfection

Lentiviral vectors derived from human immunodeficiency virus type I are widely used to deliver functional gene copies to mammalian cells for research and gene therapies. Post-transcriptional splicing of lentiviral vector transgene in transduced host and transfected producer cells presents barriers to widespread application of lentiviral vector-based therapies. The present study examined effects of indole derivative compound IDC16 on splicing of lentiviral vector transcripts in producer cells and corresponding yield of infectious lentiviral vectors. Indole IDC16 was shown previously to modify alternative splicing in human immunodeficiency virus type I. Human embryonic kidney 293T cells were transiently transfected by 3rd generation backbone and packaging plasmids using polyethyleneimine. Reverse transcription-quantitative polymerase chain reaction of the fraction of unspliced genomes in human embryonic kidney 293T cells increased up to 31% upon the indole's treatment at 2.5 uM. Corresponding yield of infectious lentiviral vectors decreased up to 4.5-fold in a cell transduction assay. Adjusting timing and duration of IDC16 treatment indicated that the indole's disruption of early stages of transfection and cell cycle had a greater effect on exponential time course of lentiviral vector production than its reduction of post-transcriptional splicing. Decrease in transfected human embryonic kidney 293T proliferation by IDC16 became significant at 10 uM. These findings indicated contributions by early-stage transfection, cell proliferation, and post-transcriptional splicing in transient transfection of human embryonic kidney 293T cells for lentiviral vector production.

PEGylation of Chrysin Improves Its Water Solubility while Preserving the In Vitro Biological Activity

Chrysin is a natural flavonoid that despite having numerous biological properties, its therapeutic value is limited due to its very low solubility in aqueous media. In this work, chrysin was conjugated with methoxypolyethylene glycols (mPEGs) of different molecular weights (350, 500, 750, and 2000 g/mol), affording PEGylated chrysins with high yields and excellent purities. In all cases, an increase in the water solubility of the conjugates was observed, which was highest when 500 g/mol of mPEG was used in the PEGylation reaction. Furthermore, in aqueous solution, PEGylated chrysins formed aggregates of ellipsoid shape. Electrochemical studies showed that the redox properties were conserved after PEGylation. While in vitro antibacterial and antifungal studies probed that the intrinsic activity was conserved, in vitro antitumor activities against HepG2 (liver carcinoma cells) and PC3 (prostate cancer cell) showed that PEGylated chrysins retained the cytotoxic activity and the ability of induction of apoptosis for the evaluated human cancer cells.

Cytotoxic, antioxidant, and cytoprotective properties of polyphenol-enriched extracts from pecan nutshells in MDA-MB-231 breast cancer cells

Phenolic compounds present in plants have demonstrated several biological properties such as antioxidant, antitumor, cardioprotective, and antiproliferative. On the other hand, doxorubicin, a chemotherapeutic widely used to treat breast cancer, usually exhibits chronic cardiotoxicity associated with oxidative stress. Therefore, we aimed to study the effects of phenolic compound-enriched extract (PCEE) with doxorubicin in breast cancer. To achieve this, after an SPE-C18 -column purification process of crude extracts obtained from pecan nutshells (Carya illinoinensis), the resulting PCEE was used to evaluate the cytotoxicity and antioxidant properties against the human breast cancer cell line MDA-MB-231 and the normal-hamster ovary cell line CHO-K1. PCEE was selectively cytotoxic against both cell lines, with an IC50 value (≈26.34 mg/L) for MDA-MB-231 lower than that obtained for CHO-K1 (≈55.63 mg/L). As a cytotoxic mechanism, PCEE inhibited cell growth by G2/M cell cycle arrest in MDA-MB-231 cells. Simultaneously, the study of the antioxidant activity showed that PCEE had a cytoprotective effect, evidenced by reduced ROS production in cells with oxidative stress caused by doxorubicin. The results highlight PCEE as a potential antitumor agent, thus revaluing it as an agro-industrial residue.

Variation in pentose phosphate pathway-associated metabolism dictates cytotoxicity outcomes determined by tetrazolium reduction assays

Tetrazolium reduction and resazurin assays are the mainstay of routine in vitro toxicity batteries. However, potentially erroneous characterization of cytotoxicity and cell proliferation can arise if verification of baseline interaction of test article with method employed is neglected. The current investigation aimed to demonstrate how interpretation of results from several standard cytotoxicity and proliferation assays vary in dependence on contributions from the pentose phosphate pathway (PPP). Non-tumorigenic Beas-2B cells were treated with graded concentrations of benzo[a]pyrene (B[a]P) for 24 and 48 h prior to cytotoxicity and proliferation assessment with commonly used MTT, MTS, WST1, and Alamar Blue assays. B[a]P caused enhanced metabolism of each dye assessed despite reductions in mitochondrial membrane potential and was reversed by 6-aminonicotinamide (6AN)-a glucose-6-phosphate dehydrogenase inhibitor. These results demonstrate differential sensitivity of standard cytotoxicity assessments on the PPP, thus (1) decoupling "mitochondrial activity" as an interpretation of cellular formazan and Alamar Blue metabolism, and (2) demonstrating the implicit requirement for investigators to sufficiently verify interaction of these methods in routine cytotoxicity and proliferation characterization. The nuances of method-specific extramitochondrial metabolism must be scrutinized to properly qualify specific endpoints employed, particularly under the circumstances of metabolic reprogramming.

Comparative pathogenic potential of avian influenza H7N3 viruses isolated from wild birds in Egypt and their sensitivity to commercial antiviral drugs

Active surveillance and studying the virological features of avian-origin influenza viruses are essential for early warning and preparedness for the next potential pandemic. During our active surveillance of avian influenza viruses in wild birds in Egypt in the period 2014-2017, multiple reassortant low-pathogenic avian influenza H7N3 viruses were isolated. In this study, we investigated and compared the infectivity, pathogenicity, and transmission of four different constellation forms of Egyptian H7N3 viruses in chickens and mice and assessed the sensitivity of these viruses to different commercial antiviral drugs in vitro. Considerable variation in virus pathogenicity was observed in mice infected with different H7N3 viruses. The mortality rate ranged from 20 to 100% in infected mice. Infected chickens showed only ocular clinical signs at three days postinfection as well as systemic viral infection in different organs. Efficient virus replication and transmission in chickens was observed within each group, indicating that these subtypes can spread easily from wild birds to poultry without prior adaptation. Mutations in the viral proteins associated with antiviral drug resistance were not detected, and all strains were sensitive to the antiviral drugs tested. In conclusion, all of the viruses studied had the ability to infect mice and chickens. H7N3 viruses circulating among wild birds in Egypt could threaten poultry production and public health.

Ammonium induces oxidative stress, endoplasmic reticulum stress, and apoptosis of hepatocytes in the liver cell line of grass carp (Ctenopharyngodon idella)

Under unfavorable agricultural conditions, ammonia toxicity has become a major problem, resulting in a large number of deaths. Ammonia has been shown to be hepatotoxic. Research has also shown that ammonia can damage the livers of carp, but the mechanism is unclear. In this study, normal grass carp hepatocytes (L8824) were exposed to ammonia water to investigate the effect of ammonia on hepatocyte injury and apoptosis and its mechanism. The results showed that ammonia (50 mM) reduced the viability of L8824 cells and increased glutamic pyruvic transaminase (ALT, up 144.95%, P < 0.01) and glutamic oxalacetic transaminase (AST, up 65.27%, P < 0.01). Furthermore, exposure to ammonia induced oxidative stress and endoplasmic reticulum (ER) stress in L8824 cells. Elevated levels of reactive oxygen species (ROS) and malondialdehyde (MDA) and decreased mitochondrial membrane potential indicated that L8824 cells suffered oxidative damage. Endoplasmic reticulum stress manifests as increased expression degrees of PERK, ATF4, and IRE-1α. These results confirmed the toxicity of ammonia to hepatocytes. In addition, the rate of apoptosis in L8824 cells was increased 69.66% after exposure to ammonia (50 mM, P < 0.01). However, pretreatment of L8824 cells with ER stress inhibitor 2-APB reduced ammonia-induced calcium release (26.50%, P < 0.01) in endoplasmic reticulum. These results indicate that ammonia can exert toxic effects on L8824 cells through inducing endoplasmic reticulum stress and oxidative stress, resulting in apoptosis in L8824 cells.

Improved Tool for Predicting Skin Irritation on Reconstructed Human Epidermis Models Based on Electrochemical Impedance Spectroscopy

The rabbit skin irritation test has been the standard for evaluating the irritation potential of chemicals; however, alternative methods that do not use animal testing are actively encouraged. Reconstructed human epidermis (RhE) models mimic the biochemical and physiological properties of the human epidermis and can be used as an alternative method. On RhE methods, the metabolic activity of RhE models is used to predict skin irritation, with a reduction in metabolic activity indicating a reduced number of viable cells and linking cell death to skin irritation processes. However, new challenges have emerged as the use of RhE models increases, including the need for non-invasive and marker-free methodologies to assess cellular states. Electrochemical impedance spectroscopy (EIS) is one such methodology that can meet these requirements. In this study, our results showed that EIS can differentiate between irritant and non-irritant chemicals, with a significant increase in the capacitance values observed in the irritant samples. A ROC curve analysis showed that the prediction method based on EIS met OECD TG 439 requirements at all time points and had 95% within-laboratory reproducibility. Comparison with the MTT viability assay showed that prediction using EIS achieved higher sensitivity, specificity, and accuracy. These results suggest that EIS could potentially replace animal testing in the evaluation of irritation potential and could be a valuable addition to in vitro testing strategies.

The MTT Assay: A Method for Error Minimization and Interpretation in Measuring Cytotoxicity and Estimating Cell Viability

The MTT assay is extensively used, most often to infer a measure of cytotoxicity of treatments to cells. As with any assay though, there are a number of limitations. The method described here is designed with consideration of how the MTT assay fundamentally works to account for, or at least identify, confounding factors in measurements. It also provides a decision-making framework to best interpret and complement the MTT assay to apply it as either a measure of metabolic activity or cell viability.

Real-time luminescence enables continuous drug-response analysis in adherent and suspension cell lines

The drug-induced proliferation (DIP) rate is a metric of in vitro drug response that avoids inherent biases in commonly used metrics such as 72 h viability. However, DIP rate measurements rely on direct cell counting over time, a laborious task that is subject to numerous challenges, including the need to fluorescently label cells and automatically segment nuclei. Moreover, it is incredibly difficult to directly count cells and accurately measure DIP rates for cell populations in suspension. As an alternative, we use real-time luminescence measurements derived from the cellular activity of NAD(P)H oxidoreductase to efficiently estimate drug response in both adherent and suspension cell populations to a panel of known anticancer agents. For the adherent cell lines, we collect both luminescence reads and direct cell counts over time simultaneously to assess their congruency. Our results demonstrate that the proposed approach significantly speeds up data collection, avoids the need for cellular labels and image segmentation, and opens the door to significant advances in high-throughput screening of anticancer drugs.

Fluorinated triphenylphosphonium analogs improve cell selectivity and in vivo detection of mito-metformin

Triphenylphosphonium (TPP⁺) conjugated compounds selectively target cancer cells by exploiting their hyperpolarized mitochondrial membrane potential. To date, studies have focused on modifying either the linker or the cargo of TPP⁺-conjugated compounds. Here, we investigated the biological effects of direct modification to TPP⁺ to improve the efficacy and detection of mito-metformin (MMe), a TPP⁺-conjugated probe we have shown to have promising preclinical efficacy against solid cancer cells. We designed, synthesized, and tested trifluoromethyl and methoxy MMe analogs (pCF₃-MMe, mCF₃-MMe, and pMeO-MMe) against multiple distinct human cancer cells. pCF₃-MMe showed enhanced selectivity toward cancer cells compared to MMe, while retaining the same signaling mechanism. Importantly, pCF₃-MMe allowed quantitative monitoring of cellular accumulation via ¹⁹F-NMR in vitro and in vivo. Furthermore, adding trifluoromethyl groups to TPP⁺ reduced toxicity in vivo while retaining anti-tumor efficacy, opening an avenue to de-risk these next-generation TPP⁺-conjugated compounds.

Light-Activated Gold-Selenium Core-Shell Nanocomposites with NIR-II Photoacoustic Imaging Performances for Heart-Targeted Repair

Mitochondrial dysfunction and oxidative damage represent important pathological mechanisms of myocardial ischemia-reperfusion injury (MI/RI). Searching for potential antioxidant agents to attenuate MI/RI is of great significance in clinic. Herein, gold-selenium core-shell nanostructures (AS-I/S NCs) with good near-infrared (NIR)-II photoacoustic imaging were designed for MI/RI treatment. The AS-I/S NCs after ischemic myocardium-targeted peptide (IMTP) and mitochondrial-targeted antioxidant peptide SS31 modification achieved cardiomyocytes-targeted cellular uptake and enhanced antioxidant ability and significantly inhibited oxygen-glucose deprivation-recovery (OGD/R)-induced cardiotoxicity of H9c2 cells by inhibiting the depletion of mitochondrial membrane potential (MMP) and restoring ATP synthase activity. Furthermore, the AS-I/S NCs after SS31 modification achieved mitochondria-targeted inhibition of reactive oxygen species (ROS) and subsequently attenuated oxidative damage in OGD/R-treated H9c2 cells by inhibition of apoptosis and oxidative damage, regulation of MAPKs and PI3K/AKT pathways. The in vivo AS-I/S NCs administration dramatically improved myocardial functions and angiogenesis and inhibited myocardial fibrosis through inhibiting myocardial apoptosis and oxidative damage in MI/RI of rats. Importantly, the AS-I/S NCs showed good safety and biocompatibility in vivo. Therefore, our findings validated the rational design that mitochondria-targeted selenium-gold nanocomposites could attenuate MI/RI of rats by inhibiting ROS-mediated oxidative damage and regulating MAPKs and PI3K/AKT pathways, which could be a potential therapy for the MI/RI treatment.

Cohesion mechanisms for bioadhesives

Due to the nature of non-invasive wound closure, the ability to close different forms of leaks, and the potential to immobilize various devices, bioadhesives are altering clinical practices. As one of the vital factors, bioadhesives' strength is determined by adhesion and cohesion mechanisms. As well as being essential for adhesion strength, the cohesion mechanism also influences their bulk functions and the way the adhesives can be applied. Although there are many published reports on various adhesion mechanisms, cohesion mechanisms have rarely been addressed. In this review, we have summarized the most used cohesion mechanisms. Furthermore, the relationship of cohesion strategies and adhesion strategies has been discussed, including employing the same functional groups harnessed for adhesion, using combinational approaches, and exploiting different strategies for cohesion mechanism. By providing a comprehensive insight into cohesion strategies, the paper has been integrated to offer a roadmap to facilitate the commercialization of bioadhesives.

Efficient Assay and Marker Significance of NAD+ in Human Blood

Oxidized nicotinamide adenine dinucleotide (NAD+) is a biological molecule of systemic importance. Essential role of NAD+ in cellular metabolism relies on the substrate action in various redox reactions and cellular signaling. This work introduces an efficient enzymatic assay of NAD+ content in human blood using recombinant formate dehydrogenase (FDH, EC 1.2.1.2), and demonstrates its diagnostic potential, comparing NAD+ content in the whole blood of control subjects and patients with cardiac or neurological pathologies. In the control group (n = 22, 25–70 years old), our quantification of the blood concentration of NAD+ (18 μM, minimum 15, max 23) corresponds well to NAD+ quantifications reported in literature. In patients with demyelinating neurological diseases (n = 10, 18–55 years old), the NAD+ levels significantly (p &lt; 0.0001) decrease (to 14 μM, min 13, max 16), compared to the control group. In cardiac patients with the heart failure of stage II and III according to the New York Heart Association (NYHA) functional classification (n = 24, 42–83 years old), the blood levels of NAD+ (13 μM, min 9, max 18) are lower than those in the control subjects (p &lt; 0.0001) or neurological patients (p = 0.1). A better discrimination of the cardiac and neurological patients is achieved when the ratios of NAD+ to the blood creatinine levels, mean corpuscular volume or potassium ions are compared. The proposed NAD+ assay provides an easy and robust tool for clinical analyses of an important metabolic indicator in the human blood.

Bredemolic acid restores glucose utilization and attenuates oxidative stress in palmitic acid-induced insulin-resistant C2C12 cells

Objective. Due to insulin resistance and oxidative stress that are associated with type 2 diabetes mellitus (T2DM), T2DM has become a prevalent metabolic disorder that presents various side effects. However, alternative antidiabetic treatment has commonly been used in treating diabetes mellitus in diabetic patients. In our previous studies, bredemolic acid has been reported as an antidiabetic agent that improves glucose uptake, ameliorates insulin resistance, and oxidative stress in the liver, heart, kidney, and skeletal muscle of prediabetic rats. However, these effects have not been validated in vitro. Therefore, this study was aimed to investigate the effects of bredemolic acid on insulin-mediated glucose utilization, lipid peroxidation, and the total antioxidant capacity (TOAC) in palmitic acid-induced insulin-resistant C2C12 skeletal muscle cells in vitro. Methods. Insulin resistance was induced in the skeletal muscle cells after 4 h of exposure to palmitic acid (0.5 mmol/l). Different cell groups were incubated in culture media DMEM supplemented with fetal calf serum (10%), penicillin/streptomycin (1%), and L-glutamine (1%) and then treated with either insulin (4 µg/ml) or bredemolic acid (12.5 mmol/l) or with both. Thereafter, the cells were seeded in 24- or 96-well plates for determination of the cell viability, glucose utilization, glycogen formation, and antioxidant capacity. Results. The results showed that bredemolic acid significantly improved TOAC and promoted glucose utilization via attenuation of lipid peroxidation and increased glycogen formation in the insulin-resistant cells, respectively. Conclusion. This study showed that bredemolic acid restored the insulin resistance through improved glucose utilization, glycogen formation, and TOAC in the skeletal muscle cells.

Cellular and molecular pathways underlying the nephrotoxicity of gadolinium

Mounting evidence on the short- and long-term adverse effects associated with gadolinium [Gd (III)]-based contrast agents used in magnetic resonance imaging have emerged in the past three decades. Safety issues arise from the release of Gd (III) from chelates and its deposition in tissues, which is exacerbated in patients with renal disease, since the kidney is the major excretion organ of most of these agents. This study aimed at unveiling the cellular and molecular mechanisms of nephrotoxicity of Gd (III), using an in vitro model of human proximal tubular cells (HK-2 cell line). Cell viability declined in a concentration- and time-dependent manner after exposure to GdCl3·6H2O. The estimated inhibitory concentrations (ICs) eliciting 1 to 50% of cell death, after 24 h of exposure, ranged from 3.4 to 340.5 µM. At toxic concentrations, exposure to Gd (III) led to disruption of the oxidative status, mitochondrial dysfunction, cell death by apoptosis, switching to necrosis at higher levels, and autophagic activation. Disturbance of the lipid metabolism was already observed at low-toxicity ICs, with accumulation of lipid droplets, and upregulation of genes related to both lipogenesis and lipolysis. Gd (III)-exposure, even at the subtoxic IC01, increased the expression of modulators of various signaling pathways involved in the development and progression of renal disease, including inflammation, hypoxia and fibrosis. Our results give new insights into the mechanisms underlying the nephrotoxic potential of Gd (III) and highlight the need to further clarify the risks versus benefits of the Gd (III)-based contrast agents currently in use.

Comparative assessment of antimicrobial, antiradical and cytotoxic activities of cannabidiol and its propyl analogue cannabidivarin

Cannabidiol and cannabidivarin are phytocannabinoids produced by Cannabis indica and Cannabis sativa. Cannabidiol has been studied more extensively than its propyl analogue cannabidivarin. Therefore, we performed a battery of in vitro biological assays to compare the cytotoxic, antiradical and antibacterial activities of both cannabinoids. Potential mitochondrial metabolism alterations, DNA synthesis inhibition, and plasma membrane damage were studied by MTT assay, BrdU-ELISA and LDH assay of cancer and normal human cells exposed to cannabinoids. ABTS and DPPH assays were performed to observe the effects of the cannabinoids on free radicals. Microbial susceptibility tests were performed to study the activity of the cannabinoids in two bacterial species implicated in human infections, Escherichia coli and Staphylococcus aureus. The results showed that the cannabinoids induced medium levels of cytotoxicity in cancer and normal cells at concentrations ranging from 15.80 to 48.63 and from 31.89 to 151.70 µM, respectively, after 72 h of exposure. Cannabinoids did not exhibit a strong antioxidant capacity in scavenging ABTS or DPPH radicals. No evident differences were observed between the two cannabinoids in antimicrobial activity, except with respect to S. aureus, which showed greater susceptibility to cannabidiol than to cannabidivarin after 72 h of exposure.

Extraction of phenolic compounds from the shells of pecan nuts with cytotoxic activity through apoptosis against the colon cancer cell line HT-29

The water extraction of phenolic compounds from two varieties ("Mahan" and "Marameck") of pecan nutshells (Carya illinoinensis) without and with sonication, varying the solvent/solid ratio (S), the pH, and the refluxing time (t), was studied. Additionally, the in vitro cytotoxicity and the determination of the cell death mechanism of the extracts against the colon cancer cell line HT-29 were investigated. The content of total phenolic compounds (TPC) of "Marameck" nutshells resulted higher than for the "Mahan" variety, and the pH increase resulted in higher TPC contents for both cultivars. The optimized conditions for TPC extraction without and with sonication resulted: S = 33 ml/g, pH = 12, and t = 9.6 min, and yielded ≈ 70 and 90 mg/g of TPC for "Mahan" and "Marameck" nutshells, respectively. The optimized extracts of pecan nutshells without sonication from both cultivars presented similar cytotoxicity against HT-29 colon cancer cells (IC₅₀  ≈ 50 µg/ml), higher than for sonicated extracts (IC₅₀ ≈ 88 and 138 µg/ml for "Mahan" and "Marameck," respectively). Cell death through apoptosis was the main mechanism of cell death induced by the nutshell extracts. PRACTICAL APPLICATION: The extraction of phenolic compounds (TPC) from the residues of two varieties of pecan nutshells ("Mahan" and "Marameck") was studied. An optimal combination of variables within the pH range that minimizes the solvent-to-solid ratio (S) and the time of refluxing (t), saving at the same time, water and energy, was set up. The phenolic compound extracts obtained from the residues of the pecan nuts exhibit cytotoxic effects against colon cancer cells and could be of interest as an alternative treatment of different types of cancer. Additionally, these extracts may be of importance to the food industry as they can be used as antioxidant agents in food formulation. Also, the high levels of anthocyanidins obtained from the pecan nut extracts after proanthocyanidins' strong acid hydrolysis can be purified and employed as natural red dyes.

Cytotoxicity and Antiviral Activities of Haplophyllum tuberculatum Essential Oils, Pure Compounds, and Their Combinations against Coxsackievirus B3 and B4

Haplophyllum tuberculatum is a plant commonly used in folk medicine to treat several diseases including vomiting, nausea, infections, rheumatism, and gastric pains. In the current study, H. tuberculatum essential oils, hydrosols, the pure compounds R-(+)-limonene, S-(-)-limonene, and 1-octanol, as well as their combinations R-(+)-limonene/1-octanol and S-(-)-limonene/1-octanol, were screened for their cytotoxicity on HEp-2 cells after 24, 48, and 72 h, and then tested for their activity against Coxsackievirus B3 and B4 (CV-B3 and CV-B4) at 3 different moments: addition of the plant compounds before, after, or together with virus inoculation. Results showed that the samples were more cytotoxic after 72 h than after 24 h or 48 h cell contact. However, the combinations R-(+)-limonene/1-octanol and S-(-)-limonene/1-octanol showed less effect on HEp-2 cells than pure R-(+)-limonene and S-(-)-limonene after 24 h, 48 h, and 72 h. 1-octanol exhibited the highest concentration causing 50% cytotoxicity (CC₅₀) on HEp-2 cells after 24 h (CC₅₀ = 93 µg/mL) and 48 h (CC₅₀ = 83 µg/mL). The antiviral assays showed that the tested samples exhibited potent inhibition of CV-B. IC₅₀ values ranged from 0.66 µg/mL to 28.4 µg/mL. In addition, CV-B3 was more sensitive than CV-B4. Both CV-B strains are more inhibited when cells were pretreated with the plant compounds. The hydrosols have no effect, neither on HEp-2 cells nor on the virus. 1-octanol, S-(-), and R-(+)-limonene/1-octanol had important selectivity indexes over time. Although essential oils had potent antiviral activity, they can be considered for application in the pretreatment of cells. However, 1-octanol and the combinations are within the safety limits, and thus, they can be used as an active natural antiviral agent for CV-B3 and CV-B4 inhibition.

Advanced Nanoparticle-Based Drug Delivery Systems and Their Cellular Evaluation for Non-Small Cell Lung Cancer Treatment

Lung cancers, the number one cancer killer, can be broadly divided into small cell lung cancer (SCLC) and non-small cell lung cancer (NSCLC), with NSCLC being the most commonly diagnosed type. Anticancer agents for NSCLC suffer from various limitations that can be partly overcome by the application of nanomedicines. Nanoparticles is a branch within nanomedicine that can improve the delivery of anticancer drugs, whilst ensuring the stability and sufficient bioavailability following administration. There are many publications available in the literature exploring different types of nanoparticles from different materials. The effectiveness of a treatment option needs to be validated in suitable in vitro and/or in vivo models. This includes the developed nanoparticles, to prove their safety and efficacy. Many researchers have turned towards in vitro models that use normal cells or specific cells from diseased tissues. However, in cellular works, the physiological dynamics that is available in the body could not be mimicked entirely, and hence, there is still possible development of false positive or false negative results from the in vitro models. This article provides an overview of NSCLC, the different nanoparticles available to date, and in vitro evaluation of the nanoparticles. Different types of cells suitable for in vitro study and the important precautions to limit the development of false results are also extensively discussed.

Recent update on potential cytotoxicity, biocompatibility and preventive measures of biomaterials used in dentistry

Dental treatment is provided for a wide variety of oral health problems like dental caries, periodontal diseases, periapical infections, replacement of missing teeth and orthodontic problems. Various biomaterials, like composite resins, amalgam, glass ionomer cement, acrylic resins, metal alloys, impression materials, bone grafts, membranes, local anaesthetics, etc., are used for dental applications. The physical and chemical characteristics of these materials influence the outcome of dental treatment. It also impacts on the biological, allergic and toxic potential of biomaterials. With innovations in science and their positive results, there is also a need for awareness about the biological risks of these biomaterials. The aim of dental treatment is to have effective, yet safe, and long-lasting results for the benefit of patients. For this, it is important to have a thorough understanding of biomaterials and their effects on local and systemic health. Materials used in dentistry undergo a series of analyses before their oral applications. To the best of our knowledge, this is the first and original review that discusses the reasons for and studies on the toxicity of commonly used biomaterials for applications in dentistry. It will help clinicians to formulate a methodical approach for the selection of dental biomaterials, thus providing an awareness for forecasting their risk of toxic reactions.

The MTT assay application to measure the viability of spermatozoa: A variety of the assay protocols

The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) reduction assay is one of the methods used to evaluate the viability of sperm. In the assay, a tetrazolium component (MTT) is converted into MTT formazan by some specific enzymes in the viable cells. The amount of formazan product in theory is directly correlated with the percentage of viable sperms. It is quantified by measuring the absorbance using a spectrophotometer. The present article compiles the MTT assays that have been used to determine sperm viability in most animal species and humans. In each assay, other factors apart from the number of viable cells that potentially influence the accuracy and precision of results are stated, such as preparations of sperm and MTT solutions, length and conditions of incubation, and a solubilizing agent as well as the formazan detection method. Also, the strengths and shortcomings of the MTT test comparison with the others are summarized at the end of this article. This information may be useful for prospective researchers deciding to implement this colorimetric method in their experiments.

Oxidative stress is involved in LLLT mechanism of action on skin healing in rats

The skin injury healing process involves the main phases of homoeostasis, inflammation, proliferation, and remodeling. The present study aimed to analyze the effects of low-level laser therapy (LLLT) on hematological dynamics, oxidative stress markers, and its relation with tissue healing following skin injury. Wistar rats were divided into control, sham, skin injury, and skin injury LLLT. The biochemical and morphological analyses were performed in the inflammatory (1 and 3 days) and regenerative phases (7, 14, and 21 days) following injury. The skin injury was performed in the dorsal region, between the intrascapular lines, using a surgical punch. LLLT (Al-Ga-In-P, λ=660 nm, energy density of 20 J/cm², 30 mW power, and a time of 40 s) was applied at the area immediately after injury and on every following day according to the experimental subgroups. LLLT maintained hematocrit and hemoglobin levels until the 3rd day of treatment. Surprisingly, LLLT increased total leukocytes levels compared to control until the 3rd day. The effects of LLLT on mitochondrial activity were demonstrated by the significant increase in MTT levels in both inflammatory and regenerative phases (from the 1st to the 7th day), but only when associated with skin injury. The results indicated that LLLT modulated the inflammatory response intensity and accelerated skin tissue healing by a mechanism that involved oxidative damage reduction mostly at early stages of skin healing (inflammatory phase).

Subcellular mechanism of microbial inactivation during water disinfection by cold atmospheric-pressure plasma

Although the identification of effective reactive oxygen species (ROS) generated by plasma has been extensively studied, yet the subcellular mechanism of microbial inactivation has never been clearly elucidated in plasma disinfection processes. In this study, subcellular mechanism of yeast cell inactivation during plasma-liquid interaction was revealed in terms of comprehensive factors including cell morphology, membrane permeability, lipid peroxidation, membrane potential, intracellular redox homeostasis (intracellular ROS and H₂O₂, and antioxidant system (SOD, CAT and GSH)), intracellular ionic equilibrium (intracellular H⁺ and K⁺) and energy metabolism (mitochondrial membrane potential, intracellular Ca²⁺ and ATP level). The ROS analysis show that ·OH, ¹O₂, ·O₂^-and H₂O₂ were generated in this plasma-liquid interaction system and ·O₂^-served as the precursor of ¹O₂. Additionally, the solution pH was reduced. Plasma can effectively inactivate yeast cells mainly via apoptosis by damaging cell membrane, intracellular redox and ion homeostasis and energy metabolism as well as causing DNA fragmentation. ROS scavengers (l-His, d-Man and SOD) and pH buffer (phosphate buffer solution, PBS) were employed to investigate the role of five antimicrobial factors (·OH, ¹O₂, ·O₂^-, H₂O₂ and low pH) in plasma sterilization. Results show that they have different influences on the aforementioned cell physiological activities. The ·OH and ¹O₂ contributed most to the yeast inactivation. The ·OH mainly attacked cell membrane and increased cell membrane permeability. The disturb of cell energy metabolism was mainly attributed to ¹O₂. The damage of cell membrane as well as extracellular low pH could break the intracellular ionic equilibrium and further reduce cell membrane potential. The remarkable increase of intracellular H₂O₂ was mainly due to the influx of extracellular H₂O₂ via destroyed cell membrane, which played a little role in yeast inactivation during 10-min plasma treatment. These findings provide comprehensive insights into the antimicrobial mechanism of plasma, which can promote the development of plasma as an alternative water disinfection strategy.

Different Methods for Cell Viability and Proliferation Assay: Essential Tools in Pharmaceutical Studies

BACKGROUND AND OBJECTIVE

The ratio of live cells to total cells in a sample is a definition for cell viability or cell toxicity. The assessment of the viable cells plays a critical role in all processes of the cell culture workflows. Overall, they are used to evaluate the survival of cells and also to optimize culture or experimental conditions following treatment with different agents or compounds, like during a drug screen. In most cases, the measurement of cell viability is the primary purpose of the experiments, for example, in pharmaceutical studies to evaluate agents' toxicity.

METHODS

A literature research was conducted on cell viability assays in MEDLINE (PubMed), Web of Science and Scopus.

RESULTS

There is a wide range of cell viability assays and different parameters such as cost, speed, and complexity of a test effect to determine the choosing method. However each method has some advantages and disadvantages and none of them is not 100% perfect method.

CONCLUSION

Accordingly, it seems that the simultaneous utility of at least two assays will cover each other disadvantages to demonstrate the effects of different agents on different cell types. For instance, when one assay measures cell metabolic health, the other one checks cells permeability. Therefore by this strategy a researcher can report with more confidence the effective doses of the examined therapeutic agents.

Combined platelet-rich plasma and cold water immersion treatment minimize the damage following a skeletal muscle stretch injury in rats

The skeletal muscle stretch injuries are commonly observed in sports. In order to stimulate tissue healing, the platelet-rich plasma (PRP) and cold water immersion (CWI) are widely used in clinical practice. This study investigated the effects of isolated or combined PRP and/or CWI on the oxidative damage determined by a stretch injury induced in gastrocnemius muscle of rats. PRP and CWI are applied immediately after the injury, and the biochemical analysis was performed after 1, 3, 5, or 7 days. The levels of o thiobarbituric acid reactive substances and oxidized dichlorofluorescein were significantly increased, both in skeletal muscle tissue and erythrocytes preparations, and the combined PRP and CWI minimized these parameters. Moreover, combined PRP and CWI were more effective than the isolated treatments to increase catalase activity, also the ratio of reduced/oxidized glutathione, and the non-protein thiols (-SH) group levels. In conclusion, we could infer that the combination of these regular treatments used in an isolated form shows a great potential for treatments of muscular injuries.

Potential Nutraceutical Properties of Leaves from Several Commonly Cultivated Plants

Chronic dietary ingestion of suitable phytochemicals may assist with limiting or negating neurodegenerative decline. Current therapeutics used to treat Alzheimer disease elicit broad adverse drug reactions, and alternative sources of cholinesterase inhibitors (ChEIs) are required. Herein, we screened methanolic extracts from seven commonly cultivated plants for their nutraceutical potential; ability to inhibit acetylcholinesterase (AChE) and butyryl-cholinesterase (BuChE), and provision of antioxidant activity through their 2,2-diphenyl-1-picryl-hydrazyl-hydrate (DPPH) free radical scavenging capabilities. Potential neurotoxicity of plant extracts was examined via application to SHSY-5Y neuroblastoma cells and quantitation of cell viability. Methanolic extracts of Citrus limon (Lemon), Bombax ceiba (Red silk-cotton), Lawsonia inermis (Henna), Eucalyptus globulus (Eucalyptus), Ocimum basilicum (Basil), Citrus reticulata (Mandarin orange), and Mentha spicata (Spearmint) all displayed concentration-dependent inhibition of AChE and BuChE. The majority of extracts inhibited AChE and BuChE to near equipotency, with Henna and Eucalyptus extracts the two most potent ChEIs. All plant extracts were able to scavenge free radicals in a concentration-dependent manner, with Eucalyptus the most potent antioxidant. Toxicity of plant extracts to neuronal cells was concentration dependent, with Eucalyptus also the most toxic extract. Fractionation of plant extracts and analysis by mass spectrometry identified a number of plant polyphenols that might have contributed to the cholinesterase inhibition: 3-caffeoylquinic acid, methyl 4-caffeoylquinate, kaempferol-acetyl-glycoside, quercetin 3-rutinoside, quercetin-acetyl-glycoside, kaempferol 3-O-glucoside, and quercetin 3-O-glucoside. In silico molecular modeling of these polyphenols demonstrated their improved AChE and BuChE binding affinities compared to the current FDA-approved dual ChEI, galantamine. Collectively, all the plant extracts contained nutraceutical agents as antioxidants and ChEIs and, therefore, their chronic consumption may prove beneficial to combat the pathological deficits that accrue in Alzheimer disease.

Selective Targeting of Cancerous Mitochondria and Suppression of Tumor Growth Using Redox-Active Treatment Adjuvant

Redox-active substances and their combinations, such as of quinone/ascorbate and in particular menadione/ascorbate (M/A; also named Apatone®), attract attention with their unusual ability to kill cancer cells without affecting the viability of normal cells as well as with the synergistic anticancer effect of both molecules. So far, the primary mechanism of M/A-mediated anticancer effects has not been linked to the mitochondria. The aim of our study was to clarify whether this “combination drug” affects mitochondrial functionality specifically in cancer cells. Studies were conducted on cancer cells (Jurkat, Colon26, and MCF7) and normal cells (normal lymphocytes, FHC, and MCF10A), treated with different concentrations of menadione, ascorbate, and/or their combination (2/200, 3/300, 5/500, 10/1000, and 20/2000 μM/μM of M/A). M/A exhibited highly specific and synergistic suppression on cancer cell growth but without adversely affecting the viability of normal cells at pharmacologically attainable concentrations. In M/A-treated cancer cells, the cytostatic/cytotoxic effect is accompanied by (i) extremely high production of mitochondrial superoxide (up to 15-fold over the control level), (ii) a significant decrease of mitochondrial membrane potential, (iii) a decrease of the steady-state levels of ATP, succinate, NADH, and NAD⁺, and (iv) a decreased expression of programed cell death ligand 1 (PD-L1)—one of the major immune checkpoints. These effects were dose dependent. The inhibition of NQO1 by dicoumarol increased mitochondrial superoxide and sensitized cancer cells to M/A. In normal cells, M/A induced relatively low and dose-independent increase of mitochondrial superoxide and mild oxidative stress, which seems to be well tolerated. These data suggest that all anticancer effects of M/A result from a specific mechanism, tightly connected to the mitochondria of cancer cells. At low/tolerable doses of M/A (1/100-3/300 μM/μM) attainable in cancer by oral and parenteral administration, M/A sensitized cancer cells to conventional anticancer drugs, exhibiting synergistic or additive cytotoxicity accompanied by impressive induction of apoptosis. Combinations of M/A with 13 anticancer drugs were investigated (ABT-737, barasertib, bleomycin, BEZ-235, bortezomib, cisplatin, everolimus, lomustine, lonafarnib, MG-132, MLN-2238, palbociclib, and PI-103). Low/tolerable doses of M/A did not induce irreversible cytotoxicity in cancer cells but did cause irreversible metabolic changes, including: (i) a decrease of succinate and NADH, (ii) depolarization of the mitochondrial membrane, and (iii) overproduction of superoxide in the mitochondria of cancer cells only. In addition, M/A suppressed tumor growth in vivo after oral administration in mice with melanoma and the drug downregulated PD-L1 in melanoma cells. Experimental data suggest a great potential for beneficial anticancer effects of M/A through increasing the sensitivity of cancer cells to conventional anticancer therapy, as well as to the immune system, while sparing normal cells. We hypothesize that M/A-mediated anticancer effects are triggered by redox cycling of both substances, specifically within dysfunctional mitochondria. M/A may also have a beneficial effect on the immune system, making cancer cells “visible” and more vulnerable to the native immune response.

Safety assessment of a newly synthesized copolymer for micellar delivery of hydrophobic caffeic acid phenethyl ester

Caffeic acid phenethyl ester (CAPE), a major pharmacologically active component of poplar type propolis, is known for its proapoptotic, anti-inflammatory, antioxidant, antiviral, and enzyme inhibiting activities. The aim of this study was to perform an in vitro and in vivo safety assessment of a micellar system based on a newly synthesized copolymer, consisting of polyglycidol and poly(allyl glycidyl ether) (C₁₂-PAGE-PG) as a drug delivery platform for CAPE. The in vitro studies on HepG2 and L929 cells by MTT and LDH assays after treatment with the empty and CAPE-loaded micelles showed no cytotoxic effects of the empty micelles and retained cytotoxic activity of CAPE loaded in the micelles. No hemolysis or stimulation of mouse lymphocytes or macrophages was observed in vitro. In vivo hematological, biochemical, and histological assays on rats, treated with the empty (2580 and 5160 µg/kg) or CAPE-loaded (375 and 750 µg CAPE/kg) micelles did not reveal pathological changes of any of the parameters assayed after 14-days' treatment. In conclusion, initial toxicological data characterize C₁₂-PAGE-PG as a non-toxic and promising copolymer for development of micellar drug delivery systems, particularly for a hydrophobic active substance as CAPE.

Manganese-induced neurotoxicity in cerebellar granule neurons due to perturbation of cell network pathways with potential implications for neurodegenerative disorders

Manganese (Mn) is essential for living organisms, playing an important role in nervous system function. Nevertheless, chronic and/or acute exposure to this metal, especially during early life stages, can lead to neurotoxicity and dementia by unclear mechanisms. Thus, based on previous works of our group with yeast and zebrafish, we hypothesized that the mechanisms mediating manganese-induced neurotoxicity can be associated with the alteration of protein metabolism. These mechanisms may also depend on the chemical speciation of manganese. Therefore, the current study aimed at investigating the mechanisms mediating the toxic effects of manganese in primary cultures of cerebellar granule neurons (CGNs). By exposing cultured CGNs to different chemical species of manganese ([[2-[(dithiocarboxy)amino]ethyl]carbamodithioato]](2-)-kS,kS']manganese, named maneb (MB), and [[1,2-ethanediylbis[carbamodithioato]](2-)]manganese mixture with [[1,2-ethanediylbis[carbamodithioato]](2-)]zinc, named mancozeb (MZ), and manganese chloride (MnCl₂)), and using the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay, we observed that both MB and MZ induced similar cytotoxicity (LC₅₀∼ 7-9 μM), which was higher than that of MnCl₂ (LC₅₀∼ 27 μM). Subsequently, we applied systems biology approaches, including metallomics, proteomics, gene expression and bioinformatics, and revealed that independent of chemical speciation, for non-cytotoxic concentrations (0.3-3 μM), Mn-induced neurotoxicity in CGNs is associated with metal dyshomeostasis and impaired protein metabolism. In this way, we verified that MB induced more post-translational alterations than MnCl₂, which can be a plausible explanation for cytotoxic differences between both chemical species. The metabolism of proteins is one of the most energy consuming cellular processes and its impairment appears to be a key event of some cellular stress processes reported separately in other studies such as cell cycle arrest, energy impairment, cell signaling, excitotoxicity, immune response, potential protein accumulation and apoptosis. Interestingly, we verified that Mn-induced neurotoxicity shares pathways associated with the development of Alzheimer's disease, Amyotrophic Lateral Sclerosis, Huntington's disease, and Parkinson's disease. This has been observed in baker's yeast and zebrafish suggesting that the mode of action of Mn may be evolutionarily conserved.

Carbamazepine induces a bioenergetics disruption to microvascular endothelial cells from the blood-brain barrier

Carbamazepine (CBZ) is a widely employed anti-seizure medication that crosses the blood-brain barrier (BBB) to exert its anti-convulsant action. The effects of CBZ on components of the BBB have yet to be completely delineated. Hence the current study evaluated the effects of CBZ upon mitochondrial functionality of BBB-derived microvascular endothelial cells isolated from Albino rats. The influence of CBZ on cell viability and barrier functions were evaluated by 3-(4,5 dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide (MTT), lactate dehydrogenase, and electrophysiological assays over a drug concentration range of 0.1-1000 μM. Bioenergetics effects were measured via ATP production, mitochondrial complexes I and III activities, lactate production, and oxygen consumption rates (OCRs), and mitochondrial membrane potential, fluidity and lipid content. CBZ was cytotoxic to microvascular endothelial cells in a concentration and duration dependent manner. CBZ significantly diminished the endothelial cell's barrier functions, and impacted upon cellular bioenergetics: reducing mitochondrial complex activities with a parallel decrease in OCRs and increased anaerobic lactate production. CBZ significantly decreased mitochondrial membrane potential and induced an increase of membrane fluidity and decrease in levels of mitochondrial saturated and unsaturated fatty acids. In summary, CBZ disrupted functional activity of BBB endothelial cells via damage and modification of mitochondria functionality at therapeutically relevant concentrations.

Radiation-induced transgenerational effects in animals

According to the results of recent studies, parental exposure to ionizing radiation not only leads to mutation induction in the germline of irradiated animals but also affects their non-exposed offspring. These radiation-induced transgenerational effects belong to an epigenetic phenomenon that could not be defined as a transmission of altered phenotypes from the irradiated parents to their non-exposed offspring. In this review, we present the results of laboratory studies aimed to evaluate the transgenerational effects of parental irradiation on a number of traits in the offspring of exposed parents. The results of animal studies showing compromised viability, fertility and genome stability among the non-exposed offspring of irradiated parents are presented and discussed. So far, the epigenetic phenomenon of radiation-induced transgenerational effects has been established in laboratory studies. Future work should address the important issue of manifestation of radiation-induced transgenerational effects in populations inhabiting radioactive-contaminated areas, as well as the mechanisms of transgenerational effects.

MTT versus other cell viability assays to evaluate the biocompatibility of root canal filling materials: a systematic review

OBJECTIVES

This systematic review aimed to compare the cytotoxicity of root canal filling materials (RCFMs) assessed using tetrazolium salt-based tests (TSBT), including the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay, with those obtained using other cell viability assays.

METHODS

A search was performed on PubMed, Scopus, Web of Science and OpenGrey up to March 2019, followed by a manual search. According to the Participants, Exposure, Comparator and Outcomes (PECO) criteria, in vitro studies that evaluated the cytotoxic effect of RCFMss on animal and/or human cells through TSBT and at least one other viability assay were compared. The methodological quality of selected papers was assessed using ToxRTool^® and SciRAP^® . Data were analysed using Wilcoxon's signed-rank test for paired samples and linear weighting kappa.

RESULTS

A total of 230 non-duplicated records were identified. After applying the eligibility criteria, 55 studies were selected for methodological evaluation, seven were selected by manual searching, 22 were excluded for methodological reasons, and 40 were included. A total of 410 comparisons were performed between TSBT and distinct cell viability tests (DCVT). MTT had moderate concordance with DCVT using human cells (n = 138 samples) (P = 0.507; k = 0.4225) and animal cells (n = 122 samples) (P = 0.124; k = 0.5775). XTT had good concordance using human (n = 110 samples) (P = 0.507; k = 0.6336) and animal cells (n = 12 samples) (P = 0.564; k = 0.6604). MTT, XTT, WST and MTS assays showed moderate concordance with DCVT (n = 410 samples) (P = 0.375; k = 0.5138) and complete agreement in 226 samples.

DISCUSSION

The included studies had methodological heterogeneity that was minimized by the systematic review methodology.

CONCLUSIONS

MTT and XTT do not cause over- or underestimation of cell viability during cytotoxicity screening of root canal filling materials, implying that these assays can be considered reliable for this purpose. Nonetheless, the development of protocols for the cytotoxic screening of these materials on 3D tissue-like cultures aiming to improve their predictability in the clinical scenario is suggested.

Biological Activities of Cyclic and Acyclic B-Type Laxaphycins in SH-SY5Y Human Neuroblastoma Cells

Laxaphycins are a family of non-ribosomal lipopeptides that have been isolated from several cyanobacteria. Some of these compounds have presented cytotoxic activities, but their mechanism of action is poorly understood. In this work, the already described laxaphycins B and B3, and acyclolaxaphycins B and B3 were isolated from the marine cyanobacteria Anabaena torulosa. Moreover, two new acyclic compounds, [des-(Ala⁴-Hle⁵)] acyclolaxaphycins B and B3, were purified from the herviborous gastropod Stylocheilus striatus, with this being the first description of biotransformed laxaphycins. The structure of these new compounds was elucidated, together with the absolute configuration of acyclolaxaphycins B and B3. The bioactivities of the six peptides were determined in SH-SY5Y human neuroblastoma cells. Laxaphycins B and B3 were cytotoxic (IC₅₀: 1.8 and 0.8 µM, respectively) through the induction of apoptosis. In comparison, acyclic laxaphycins did not show cytotoxicity but affected mitochondrial functioning, so their effect on autophagy-related protein expression was analyzed, finding that acyclic peptides affected this process by increasing AMPK phosphorylation and inhibiting mTOR. This work confirms the pro-apoptotic properties of cyclic laxaphycins B and is the first report indicating the effects on autophagy of their acyclic analogs. Moreover, gastropod-derived compounds presented ring opening and amino-acids deletion, a biotransformation that had not been previously described.

Exploration of the cellular effects of the high-dose, long-term exposure to coffee roasting product furan and its by-product cis-2-butene-1,4-dial on human and rat hepatocytes

Coffee is the most popular hot beverage and caffeine is the most used psychoactive drug in the world. Roasting of coffee beans leads to the generation of minute quantities of undesirable compounds, such as furan. It is now thought that the toxicity of furan derives from its processing by CYP450 family of detoxifying enzymes, leading to the formation of cis-2-butene-1,4-dial (BDA). BDA has known cytotoxicity capacities, binding to proteins, nucleic acids, and glutathione (GSH). BDA also appears to mediate furan's toxic effects, since the inhibition of CYP450 family impedes the aforementioned toxicological effects of furan. There are some studies performed on furan's toxicity, but very few on BDA. Furthermore, the doses used in these studies appear to be fairly high when compared with the expected dosage one could be exposed to in a standard day. As such, to understand if furan and BDA could have toxic effects using more realistic doses and longer time frames, human and rat hepatocytes were exposed to furan or BDA for up to 96 h, and several biochemical parameters were assessed. We report here that human hepatocytes were more sensitive than rat's, in particular to furan, for we show a decrease in MTT reduction, ATP levels and increase in carbonyl formation and 8-OHdG accumulation in the longer time points. BDA was mostly ineffective, which we attribute to a low import rate into the cells. In conclusion, we show that there is potential for harm from furan in high doses, which should be carefully addressed.

Utilising Magnetically Isolated Lysosomes for Direct Quantification of Intralysosomal Drug Concentrations by LC-MS/MS Analysis: An Investigatory Study With Imipramine

Lysosomes are acidic intracellular organelles that can extensively sequester basic lipophilic drugs due to pH and membrane partitioning, and therefore may significantly influence subcellular drug concentrations. Current in vitro methods for lysosomal drug sequestration evaluation typically lack the ability to accurately and sensitively quantify drug concentrations directly within the lysosome. In the current study, magnetic lysosomal isolation was used in the lysosome rich rat NR8383 cell line and combined with LC-MS/MS analysis to quantify intralysosomal concentrations and lysosomal partitioning (Kp_Lysosome) values of imipramine. The purity of the isolated lysosomes was validated by enzymatic and electron microscopy analysis. Lysosomal imipramine accumulation was explored using 2 methods: addition of imipramine to cells followed by lysosomal isolation (Method 1), and direct addition of imipramine to isolated lysosomes (Method 2). This work highlighted that both experimental buffers and ATP influence intralysosomal drug concentrations, and non-specific drug binding and re-distribution limits the use of Method 1. Method 2 may benefit future lysosomal drug accumulation studies, as imipramine demonstrated high Kp_Lysosome values (3500), comparable to in silico predictions. This study reports a novel method for the direct quantification of intralysosomal drug concentrations that has the ability to be adapted to other cell types.

Immunomodulatory Potential of Differently-Terminated Ultra-Small Silicon Carbide Nanoparticles

Ultra-small nanoparticles with sizes comparable to those of pores in the cellular membrane possess significant potential for application in the field of biomedicine. Silicon carbide ultra-small nanoparticles with varying surface termination were tested for the biological system represented by different human cells (using a human osteoblastic cell line as the reference system and a monocyte/macrophage cell line as immune cells). The three tested nanoparticle surface terminations resulted in the observation of different effects on cell metabolic activity. These effects were mostly noticeable in cases of monocytic cells, where each type of particle caused a completely different response ('as-prepared' particles, i.e., were highly cytotoxic, -OH terminated particles slightly increased the metabolic activity, while -NH2 terminated particles caused an almost doubled metabolic activity) after 24 h of incubation. Subsequently, the release of cytokines from such treated monocytes and their differentiation into activated cells was determined. The results revealed the potential modulation of immune cell behavior following stimulation with particular ultra-small nanoparticles, thus opening up new fields for novel silicon carbide nanoparticle biomedical applications.

Generation Dependent Effects and Entrance to Mitochondria of Hybrid Dendrimers on Normal and Cancer Neuronal Cells In Vitro

Dendrimers as drug carriers can be utilized for drugs and siRNA delivery in central nervous system (CNS) disorders, including various types of cancers, such as neuroblastomas and gliomas. They have also been considered as drugs per se, for example as anti-Alzheimer's disease (AD), anti-cancer, anti-prion or anti-inflammatory agents. Since the influence of carbosilane-viologen-phosphorus dendrimers (SMT1 and SMT2) on the basic cellular processes of nerve cells had not been investigated, we examined the impact of two generations of these hybrid macromolecules on two murine cell lines-cancer cell line N2a (mouse neuroblastoma) and normal immortalized cell line mHippoE-18 (embryonic mouse hippocampal cell line). We examined alterations in cellular responses including the activity of mitochondrial dehydrogenases, the generation of reactive oxygen species (ROS), changes in mitochondrial membrane potential, and morphological modifications and fractions of apoptotic and dead cells. Our results show that both dendrimers at low concentrations affected the cancer cell line more than the normal one. Also, generation-dependent effects were found: the highest generation induced greater cytotoxic effects and morphological modifications. The most promising is that the changes in mitochondrial membrane potential and transmission electron microscopy (TEM) images indicate that dendrimer SMT1 can reach mitochondria. Thus, SMT1 and SMT2 seem to have potential as nanocarriers to mitochondria or anti-cancer drugs per se in CNS disorders.

Mapping benznidazole resistance in trypanosomatids and exploring evolutionary histories of nitroreductases and ABCG transporter protein sequences

The nitro-heterocyclic compound benznidazole (BZ) is the first-line drug for the treatment of Chagas disease, caused by the protozoan Trypanosoma cruzi. However, therapeutic failures are common for reasons that include the influences of parasite and host genetics, the effects of toxicity on adherence to treatment, and difficulties in demonstrating parasitological cure. To obtain information on the origin of the resistance to BZ and eliminate from the scenery the participation of the host, initially we mapped the susceptibility to the drug in thirteen species of seven genera of the family Trypanosomatidae. We verified that all Trypanosoma species are sensitive to low concentrations of the drug (IC₅₀ 2.7 to 25 µM) while Non-Trypanosoma species are highly resistant to these concentrations. The two groups of parasites correspond to the major phylogenetic lineages of trypanosomatids. Next, we searched in the trypanosomatid genome databases homologs of two type-I nitroreductases (NTR-1 and OYE) and an ABC transporter (ABCG1) that have been associated with BZ resistance in T. cruzi. The predicted proteins were characterized regarding domains and used for phylogenetic analyses. Homologous NTR-1 genes were found in all trypanosomatids investigated and the structural characteristics of the enzyme suggest that it may be functional. OYE genes were absent in BZ-sensitive African trypanosomes, which excludes the participation of this enzyme in BZ bio-activation. Two copies of ABCG1 genes were observed in most BZ resistant species, while Trypanosoma species exhibit only one copy per haploid genome. Functional studies are required to verify the involvement of these genes in BZ resistance. In addition, since multiple mechanisms can contribute to BZ susceptibility, our study poses a range of organisms highly resistant to BZ in which these aspects can be investigated. Preliminary studies on BZ uptake indicate marked differences between BZ-sensitive and BZ-resistant species.

Oxidative Damage in Human Periodontal Ligament Fibroblast (hPLF) after Methylmercury Exposure

Human exposure to mercury (Hg) is primary associated with its organic form, methylmercury (MeHg), through the ingestion of contaminated seafood. However, Hg contamination is also positively correlated with the number of dental restorations, total surface of amalgam, and organic mercury concentration in the saliva. Among the cells existing in the oral cavity, human periodontal ligament fibroblast (hPLF) cells are important cells responsible for the production of matrix and extracellular collagen, besides sustentation, renewal, repair, and tissue regeneration. In this way, the present study is aimed at investigating the potential oxidative effects caused by MeHg on hPLF. Firstly, we analyzed the cytotoxic effects of MeHg (general metabolism status, cell viability, and mercury accumulation) followed by the parameters related to oxidative stress (total antioxidant capacity, GSH levels, and DNA damage). Our results demonstrated that MeHg toxicity increased in accordance with the rise of MeHg concentration in the exposure solutions (1-7 μM) causing 100% of cell death at 7 μM MeHg exposure. The general metabolism status was firstly affected by 2 μM MeHg exposure (43.8 ± 1.7%), while a significant decrease of cell viability has arisen significantly only at 3 μM MeHg exposure (68.7 ± 1.4%). The ratio among these two analyses (named fold change) demonstrated viable hPLF with compromised cellular machinery along with the range of MeHg exposure. Subsequently, two distinct MeHg concentrations (0.3 and 3 μM) were chosen based on LC50 value (4.2 μM). hPLF exposed to these two MeHg concentrations showed an intracellular Hg accumulation as a linear-type saturation curve indicating that metal accumulated diffusively in the cells, typical for metal organic forms such as methyl. The levels of total GSH decreased 50% at exposure to 3 μM MeHg when compared to control. Finally, no alteration in the DNA integrity was observed at 0.3 μM MeHg exposure, but 3 μM MeHg caused significant damage. In conclusion, it was observed that MeHg exposure affected the general metabolism status of hPLF with no necessary decrease on the cell death. Additionally, although the oxidative imbalance in the hPLF was confirmed only at 3 μM MeHg through the increase of total GSH level and DNA damage, the lower concentration of MeHg used (0.3 μM) requires attention since the intracellular mercury accumulation may be toxic at chronic exposures.

Evaluation of Sucrose Laurate as an Intestinal Permeation Enhancer for Macromolecules: Ex Vivo and In Vivo Studies

Oral delivery of macromolecules requires permeation enhancers (PEs) adaptable to formulation. Sucrose laurate (SL) (D1216), a food grade surfactant, was assessed in Caco-2 monolayers, isolated rat intestinal tissue mucosae, and rat intestinal instillations. Accordingly, 1 mM SL increased the apparent permeability coefficient (Papp) of [14C]-mannitol and reduced transepithelial electrical resistance (TEER) across monolayers. It altered expression of the tight junction protein, ZO-1, increased plasma membrane potential, and decreased mitochondrial membrane potential in Caco-2 cells. The concentrations that increased flux were of the same order as those that induced cytotoxicity. In rat colonic tissue mucosae, the same patterns emerged in respect to the concentration-dependent increases in paracellular marker fluxes and TEER reductions with 5 mM being the key concentration. While the histology revealed some perturbation, ion transport capacity was retained. In rat jejunal and colonic instillations, 50 and 100 mM SL co-administered with insulin induced blood glucose reductions and achieved relative bioavailability values of 2.4% and 8.9%, respectively, on a par with the gold standard PE, sodium caprate (C10). The histology of the intestinal loops revealed little damage. In conclusion, SL is a candidate PE with high potential for emulsion-based systems. The primary action is plasma membrane perturbation, leading to tight junction openings and a predominant paracellular flux.

Titanium - castor oil based polyurethane composite foams for bone tissue engineering

Polyurethanes (PU) foams with titanium particles (Ti) were prepared with castor oil (CO) and isophorone diisocyanate (IPDI) as polymeric matrix, and 1, 3 and 5 wt.% of Ti. Composites were physicochemically and mechanically characterized and their biocompatibility assessed using human dental pulp stem cells (HDPSC). PU synthesis was confirmed by FTIR, but the presence of Ti was detected by RAMAN, X-ray diffraction (peak at 2θ = 40.2°) and by EDX-mapping. Materials showed three decomposition temperatures between 300 °C and 500 °C and their decomposition were not catalyzed by Ti particles. Compressive modulus (164-846 kPa), compressive strength (12.9-116.7 kPa) and density (128-240 kg/m³) tend to increase with Ti concentration but porosity was reduced (87% to 80%). Composites' foams were fully degraded in acid and oxidative media while remained stable in distilled water. HDPSC viability on all composites was higher than 80% up to 14 days while proliferation dropped up to 60% at 21 days. Overall, these results suggest that these foams can be used as scaffolds for bone tissue regeneration.

Effect of peptidases secreted by the opportunistic pathogen Scedosporium aurantiacum on human epithelial cells

Peptidases secreted by a clinical high-virulence Scedosporium aurantiacum isolate (strain WM 06.482; CBS 136046) under normoxic and hypoxic conditions were separated via size-exclusion chromatography, and peptidase activities present in each fraction were determined using class-specific substrates. The fractions demonstrating peptidase activity were assessed for their effects on the attachment and viability of A549 human lung epithelial cells in vitro. Of the peptidases detected in the size-exclusion chromatography fractions, the elastase-like peptidase reduced cell viability, the chymotrypsin-like peptidase was associated with cell detachment, and the cysteine peptidases were able to abolish both cell attachment and viability. The loss of cell viability and attachment became more prominent with an increase in the peptidase activity and could also be specifically prevented by addition of class-specific peptidase inhibitors. Our findings indicate that peptidases secreted by S. aurantiacum can breach the human alveolar epithelial cell barrier and, thus, may have a role in the pathobiology of the organism.

Chemical Composition of East Asian Invasive Knotweeds, their Cytotoxicity and Antimicrobial Efficacy Against Cariogenic Pathogens: An In-Vitro Study

BACKGROUND Giant knotweeds originating from East Asia, such as Reynoutria japonica, and Reynoutria sachalinensis, and their hybrid such as Reynoutria x bohemica, are invasive plants in Europe and North America. However, R. japonica is also a traditional East Asian drug (Polygoni cuspidati rhizoma) used in Korean folk medicine to improve oral hygiene. The aim of this study was to evaluate the antibacterial activity of acetone extracts of Reynoutria species against dominant caries pathogen such as Streptococcus mutans and alternative pathogens, as well as characterize the phytochemical composition of extracts and examine their cytotoxicity. MATERIAL AND METHODS Ultrasonic extraction was used to obtain polyphenol-rich extracts. The extracts were characterized by HPLC-DAD-ESI-MS. To test bacterial viability, the minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) against S. mutans, S. salivarius, S. sanguinis, and S. pyogenes were determined. The cytotoxicity of the extracts to human fibroblasts derived from gingiva was evaluated using the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay. RESULTS The R. japonica extract had the highest bacteriostatic and bactericidal activity against pathogens causing caries, mainly dominant caries pathogen S. mutans (mean MIC 1000 μg/mL and MBC 2000 μg/mL), which was most likely associated with a higher content of stilbene aglycons and anthraquinone aglycons in the extract. Moreover, the R. japonica extract demonstrated the lowest cytotoxic effect on human fibroblasts and exhibited cytotoxic activity only at the concentration causing the death of all S. mutans. CONCLUSIONS The results indicate that the R. japonica acetone extract can be considered as a natural, antimicrobial agent for caries control.

Evaluation of pulmonary toxicity of benzalkonium chloride and triethylene glycol mixtures using in vitro and in vivo systems

Benzalkonium chloride (BAC) is a widely used disinfectant/preservative, and respiratory exposure to this compound has been reported to be highly toxic. Spray-form household products have been known to contain BAC together with triethylene glycol (TEG) in their solutions. The purpose of this study was to estimate the toxicity of BAC and TEG mixtures to pulmonary organs using in vitro and in vivo experiments. Human alveolar epithelial (A549) cells incubated with BAC (1-10 μg/mL) for 24 hours showed significant cytotoxicity, while TEG (up to 1000 μg/mL) did not affect cell viability. However, TEG in combination with BAC aggravated cell damage and inhibited colony formation as compared to BAC alone. TEG also exacerbated BAC-promoted production of reactive oxygen species (ROS) and reduction of glutathione (GSH) level in A549 cells. However, pretreatment of the cells with N-acetylcysteine (NAC) alleviated the cytotoxicity, indicating oxidative stress could be a mechanism of the toxicity. Quantification of intracellular BAC by LC/MS/MS showed that cellular distribution/absorption of BAC was enhanced in A549 cells when it was exposed together with TEG. Intratracheal instillation of BAC (400 μg/kg) in rats was toxic to the pulmonary tissues while that of TEG (up to 1000 μg/kg) did not show any harmful effect. A combination of nontoxic doses of BAC (200 μg/kg) and TEG (1000 μg/kg) promoted significant lung injury in rats, as shown by increased protein content and lactate dehydrogenase (LDH) activity in bronchoalveolar lavage fluids (BALF). Moreover, BAC/TEG mixture recruited inflammatory cells, polymorphonuclear leukocytes (PMNs), in terminal bronchioles and elevated cytokine levels, tumor necrosis factor α (TNF-α), and interleukin 6 (IL-6) in BALF. These results suggest that TEG can potentiate BAC-induced pulmonary toxicity and inflammation, and thus respiratory exposure to the air mist from spray-form products containing this chemical combination is potentially harmful to humans.