Mechanism of cellular 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) reduction

Vitrification protocol for immature Brycon orbignyanus ovarian tissue as an extinction escape strategy

Piracanjunba (Brycon orbignyanus) is an endangered South American fish, and ovarian tissue cryopreservation is an alternative method for preserving maternal germplasm and genetic diversity. Therefore, our aim was to test a vitrification protocol for ovarian tissue containing primary growth (PG) oocytes of B. orbignyanus as a strategy to avoid the threat of extinction. Two vitrification solutions were evaluated (VS1: 1.5 M methanol + 4.5 M propylene glycol and VS2: 1.5 M methanol + 5.5 M Me₂SO) and compared using control/fresh ovarian tissue. After vitrification, the following factors were analyzed: membrane integrity using trypan blue, morphology using a histological assessment, oxidative stress (total reactive antioxidant potential (TRAP) and reduced thiol [-SH]), mitochondrial activity using MTT, and DNA damage using a comet assay. The vitrified oocytes (VS1= 24.3 ± 0.49% and VS2= 24.8 ± 0.69%) showed higher DNA damage than the control group (control= 20.7 ± 1.03%) (P = 0.004). In contrast, in most evaluations (membrane integrity, membrane damage, oxidative stress, and mitochondrial activity), there were no discernible differences between the control group and the vitrified samples. In addition, oocyte (P = 0.883) and nuclear diameter (P = 0.118) did not change after vitrification. VS2 treatment resulted in higher nuclear damage (15.7 ± 1.45%) than in the control treatment (3.5 ± 1.19%); however, VS1 treatment did not result in significantly more damage (9.5 ± 3.01%) than in the control (P = 0.015). Therefore, the protocol for ovarian tissue vitrification tested in this study resulted in high maintenance of PG oocyte cell integrity, making it a promising alternative for B. orbignyanus maternal genome preservation.

Synthesis, structure and in vitro antiproliferative effects of alkyne-linked 1,2,4-thiadiazole hybrids including erlotinib- and ferrocene-containing derivatives

Chemotherapy is an indispensable tool to treat cancer, therefore, the development of new drugs that can treat cancer with minimal side effects and lead to more favorable prognoses is of crucial importance. A series of eleven novel 1,2,4-thiadiazoles bearing erlotinib (a known anticancer agent), phenylethynyl, ferrocenyl, and/or ferrocenethynyl moieties were synthesized in this work and characterized by NMR, IR and mass spectroscopies. The solid-phase structures were determined by single-crystal X-ray diffraction. Partial isomerisation of bis(erlotinib)-1,2,4-thiadiazole into its 1,3,4-thiadiazole isomer, leading to the isolation of a 3 : 2 isomer mixture, was observed and a plausible mechanism for isomerisation is suggested. The in vitro cytostatic effect and the long-term cytotoxicity of these thiadiazole-hybrids, as well as that of erlotinib, 3,5-dichloro-1,2,4-thiadiazole and 3,5-diiodo-1,2,4-thiadiazole were investigated against A2058 human melanoma, HepG2 human hepatocellular carcinoma, U87 human glioma, A431 human epidermoid carcinoma, and PC-3 human prostatic adenocarcinoma cell lines. Interestingly, erlotinib did not exhibit a significant cytostatic effect against these cancer cell lines. 1,2,4-Thiadiazole hybrids bearing one erlotinib moiety or both an iodine and a ferrocenethynyl group, as well as 3,5-diiodo-1,2,4-thiadiazole demonstrated good to moderate cytostatic effects. Among the synthesized 1,2,4-thiadiazole hybrids, the isomer mixture of bis-erlotinib substituted 1,2,4- and 1,3,4-thiadiazoles showed the most potent activity. This isomer mixture was proven to be the most effective in long-term cytotoxicity, too. 3,5-Diiodo-1,2,4-thiadiazole and its hybrid with one erlotinib fragment were also highly active against A431 and PC-3 proliferation. These novel compounds may serve as new leads for further study of their antiproliferative properties.

The Green toxicology approach: Insight towards the eco-toxicologically safe development of benign catalysts

Green toxicology is a novel approach increasingly applied for the development of materials and chemicals that are more benign to the environment and human health than their conventional counterparts. It includes predictive eco-toxicological assessments of chemicals during the early developmental process to exclude adverse effects. In the present study, two guanidine zinc catalysts for the ring-opening polymerization of lactide were investigated using eco-toxicological tools. Namely, the fish embryo toxicity assay for teratogenic effects, the ER (α) CALUX assay for endocrine activity and the Ames fluctuation assay for mutagenic potential were applied. Both complexes showed no endocrine activity, mutagenicity or acute aquatic toxicity, however a delayed hatch could be observed, therefore suggesting potential effects on a molecular level. This proof-of-concept study aims to assess the toxicity of guanidine zinc catalysts and is a first step towards the incorporation of toxicological assessments into chemical developmental processes to achieve a sustainable and safe production of catalysts.

Application of the Resazurin Cell Viability Assay to Monitor Escherichia coli and Salmonella Typhimurium Inactivation Mediated by Phages

Bacterial inactivation using bacteriophages (or phages) has emerged as an effective solution for bacterial infections, but the screening methods used to evaluate the effectiveness of the phages to inactivate bacteria are not fast, reliable or precise enough. The efficiency of bacterial inactivation by phages has been evaluated by monitoring bacterial concentration either by counting colony-forming units (CFU), a laborious and time-consuming method, or by monitoring the optical density (OD), a less sensitive method. In this study, the resazurin cell viability assay was used to monitor the viability of bacteria from different genera during the inactivation by different phages, and the results were compared with the standard methods used to assess bacterial inactivation. The results showed that the resazurin colorimetric cell viability assay produces similar results to the standard method of colony-counting and giving, and also more sensitive results than the OD method. The resazurin assay can be used to quickly obtain the results of the cell viability effect profile using two different bacterial strains and several different phages at the same time, which is extremely valuable in screening studies. Moreover, this methodology is established as an effective, accurate and rapid method when compared to the ones widely used to monitor bacterial inactivation mediated by phages.

Neurobehavioral alterations in a mouse model of chronic partial sleep deprivation

The night shift paradigm induces a state of chronic partial sleep deprivation (CPSD) and enhances the vulnerability to neuronal dysfunction. However, the specific neuronal impact of CPSD has not been thoroughly explored to date. In the current study, the night shift condition was mimicked in female Swiss albino mice. The classical sleep deprivation model, i.e., Modified Multiple Platform (MMP) method, was used for 8 h/day from Monday to Friday with Saturday and Sunday as a weekend off for nine weeks. Following nine weeks of night shift schedule, their neurobehavioral profile and physiological parameters were assessed along with the activity of the mitochondrial complexes, oxidative stress, serotonin levels, and inflammatory markers in the brain. Mice showed an overall hyperactive behavioral profile including hyperlocomotion, aggression, and stereotyped behavior accompanied by decreased activity of mitochondrial enzymes and serotonin levels, increased oxidative stress and inflammatory markers in whole brain homogenates. Collectively, the study points towards the occurrence of a hyperactive behavioral profile akin to mania and psychosis as a potential consequence of CPSD.

Influence of Nitric Oxide-Cyclic GMP and Oxidative STRESS on Amyloid-β Peptide Induced Decrease of Na,K-ATPase Activity in Rat Hippocampal Slices

Amyloid-β peptide (Aβ) has been shown to cause synaptic dysfunction and can render neurons vulnerable to excitotoxicity and oxidative stress. Na,K-ATPase plays an important role to maintain cell ionic equilibrium and it can be modulated by N-methyl-D-aspartate (NMDA)-nitric oxide (NO)-cyclic GMP pathway. Disruption of NO synthase (NOS) activity and reactive oxygen species (ROS) production could lead to changes in Na,K-ATPase isoforms' activities that may be detrimental to the cells. Our aim was to evaluate the signaling pathways of Aβ in relation to NMDA-NOS-cyclic GMP versus oxidative stress on α₁-/α_2,3-Na,K-ATPase activities in rat hippocampal slices. Aβ_1-40 induced a concentration-dependent increase of NOS activity and increased cyclic guanosine monophosphate (cGMP), TBARS (thiobarbituric acid reactive substances), and 3-Nitrotyrosine (3-NT)-modified protein levels in rat hippocampal slices. The increase in NOS activity and cyclic GMP levels induced by Aβ_1-40 was completely blocked by MK-801 (inhibitor of NMDA receptor) and L-NAME (inhibitor of NOS) pre-treatment but changes in TBARS levels were only partially blocked by both compounds. The Aβ treatment also decreased Na,K-ATPase activity which was reverted by N-nitro-L-arginine methyl ester hydrochloride (L-NAME) but not by MK-801 pre-treatment. The decrease in enzyme activity induced by Aβ was isoform-specific since only α₁-Na,K-ATPase was affected. These findings suggest that the activation of NMDA-NOS signaling cascade linked to α_2,3-Na,K-ATPase activity may mediate an adaptive, neuroprotective response to Aβ in rat hippocampus.

Curcumin-Coumarin Hybrid Analogues as Multitarget Agents in Neurodegenerative Disorders

Neurodegenerative diseases have a complex nature which highlights the need for multitarget ligands to address the complementary pathways involved in these diseases. Over the last decade, many innovative curcumin-based compounds have been designed and synthesized, searching for new derivatives having anti-amyloidogenic, inhibitory of tau formation, as well as anti-neuroinflammation, antioxidative, and AChE inhibitory activities. Regarding our experience studying 3-substituted coumarins with interesting properties for neurodegenerative diseases, our aim was to synthesize a new series of curcumin–coumarin hybrid analogues and evaluate their activity. Most of the 3-(7-phenyl-3,5-dioxohepta-1,6-dien-1-yl)coumarin derivatives 11–18 resulted in moderated inhibitors of hMAO isoforms and AChE and BuChE activity. Some of them are also capable of scavenger the free radical DPPH. Furthermore, compounds 14 and 16 showed neuroprotective activity against H₂O₂ in SH-SY5Y cell line. Nanoparticles formulation of these derivatives improved this property increasing the neuroprotective activity to the nanomolar range. Results suggest that by modulating the substitution pattern on both coumarin moiety and phenyl ring, ChE and MAO-targeted derivatives or derivatives with activity in cell-based phenotypic assays can be obtained.

Gamma-decanolactone: Preliminary evaluation as potential antiparkinsonian drug

Treatment of Parkinson's disease (PD) includes the use of monoamine oxidase-B (MAO-B) inhibitor drugs. In this work we have evaluated the possible gamma-decanolactone (GD) effect in vitro to inhibit the A and B isoforms of human monoamine oxidase (hMAO) enzyme and their citotoxicity in human hepatoma cell line (HepG2). Also, binding studies to A₁, A_2A A_2B and A₃ adenosine receptors were performed. A docking study of gamma-decanolactone has been carried out with the molecular targets of MAO-A and MAO-B isoforms. The physicochemical properties and ability to cross physiological barriers, as the blood brain barrier (BBB), was elucidated by computational studies. The in vivo assays, the rota-rod test, body temperature assessment and open field test were performed in reserpinized mice (1.5 mg/kg, i.p.; 18:00 before) to evaluate the effect of gamma-decanolactone (300 mg/kg), alone or associated with Levodopa plus Benserazide (LD + BZ, 100:25 mg/kg, i.p.). Gamma-decanolactone inhibited preferentially the MAO-B in a reversible manner, with an inhibitory concentration of 50% (IC₅₀) 55.95 ± 9.06 μM. It was shown to be a safe drug since only at the highest concentration decreased the viability of HepG2 cells. It also does not bind to adenosine receptors investigated in this study. The molecular docking study show that the gamma-decanolactone ligand adopts a relatively compact conformation in the active site of hMAO-B, while we note an extended conformation of gamma-decanolactone ligand in the hMAO-A isoform. The physicochemical properties obtained, and the theoretical models utilized for the evaluation of ability to cross the BBB, predict a good gamma-decanolactone bioavailability and access to the central nervous system (CNS). In the in vivo studies, gamma-decanolactone partially reversed the ataxia of the reserpinized mice at 01:00 h and 01:30 h post-administration. Concomitant treatment of gamma-decanolactone with LD + BZ, at 01:30 h showed a potentiation of the reversibility of ataxia and facilitated the reversal of hypothermia caused by reserpine for all measured times (P <0.01 vs vehicle), except at 24:00 h, but not reversed the hypokinesia in the open field test. In summary, the results herein obtained and in conjunction with previous studies, suggest that gamma-decanolactone could be a drug with potential utility as antiparkinsonian drug.

Highly Efficient Biosynthesis of Glycyrrhetinic Acid Glucosides by Coupling of Microbial Glycosyltransferase to Plant Sucrose Synthase

Glycyrrhetinic acid (GA) is a principal bioactive pentacyclic triterpenoid from Glycyrrhiza uralensis. Uridine diphosphate-dependent glycosyltransferases (UGTs) have been widely used to catalyze glycosylation of diverse nature products for the development of potential therapeutic compounds. In this study, we have characterized a UGT109A3 from Bacillus subtilis, which can glycosylate both the free C3 hydroxyl and C30 carboxyl groups of GA to yield a unique 3, 30-O-β-D-diglucoside-GA. By coupling the microbial UGT109A3 to plant sucrose synthase (SUS), GA-diglucoside could be biosynthesized in an efficient and economical way. With a fed-batch glycosylation, a large scale of GA-diglucoside (6.26 mM, 4.98 g/L in 8 h) could be enzymatically transformed from GA. The obtained GA-diglucoside showed a significant water solubility improvement of around 3.4 × 103 fold compared with that of the parent GA (29 μM). Moreover, it also exhibited dose-dependent cytotoxicity toward human colon carcinoma Caco-2 cell line according to MTT assay, having an IC50 at 160 μM. This study not only establishes efficient platform for producing GA-glucosides, but is also valuable for developing further the biosynthesis of other complex glycosylated natural products.

The Impact of High Glucose or Insulin Exposure on S100B Protein Levels, Oxidative and Nitrosative Stress and DNA Damage in Neuron-Like Cells

Alzheimer’s disease (AD) is attracting considerable interest due to its increasing number of cases as a consequence of the aging of the global population. The mainstream concept of AD neuropathology based on pathological changes of amyloid β metabolism and the formation of neurofibrillary tangles is under criticism due to the failure of Aβ-targeting drug trials. Recent findings have shown that AD is a highly complex disease involving a broad range of clinical manifestations as well as cellular and biochemical disturbances. The past decade has seen a renewed importance of metabolic disturbances in disease-relevant early pathology with challenging areas in establishing the role of local micro-fluctuations in glucose concentrations and the impact of insulin on neuronal function. The role of the S100 protein family in this interplay remains unclear and is the aim of this research. Intracellularly the S100B protein has a protective effect on neurons against the toxic effects of glutamate and stimulates neurites outgrowth and neuronal survival. At high concentrations, it can induce apoptosis. The aim of our study was to extend current knowledge of the possible impact of hyper-glycemia and -insulinemia directly on neuronal S100B secretion and comparison to oxidative stress markers such as ROS, NO and DBSs levels. In this paper, we have shown that S100B secretion decreases in neurons cultured in a high-glucose or high-insulin medium, while levels in cell lysates are increased with statistical significance. Our findings demonstrate the strong toxic impact of energetic disturbances on neuronal metabolism and the potential neuroprotective role of S100B protein.

A deleterious interplay between endoplasmic reticulum stress and its functional linkage to mitochondria in nephrolithiasis

Hyperoxaluria is one of the leading causes of calcium oxalate stone formation in the kidney. Since hyperoxaluria produces Endoplasmic Reticulum (ER) stress in the kidney, it is thus likely that the adaptive unfolded protein response might affect the mitochondrial population as ER and mitochondria share close physical and functional interactions mandatory for several biological processes. Thus this work was designed to study the putative effects of endoplasmic reticulum stress on the renal mitochondria during hyperoxaluria-induced nephrolithiasis. The results showed that hyperoxaluria induced an ER stress led to the unfolded protein response in the renal tissue of experimental rats. Hampered mitochondrion functioning was detected with decreased mitochondrial membrane potential and upsurged mitochondria calcium. These changes in the mitochondria function and ER stress are preceded by apoptosis. The expression of Sigma-1 receptor protein found in the Mitochondria associated ER membranes, the connecting link between ER and mitochondria was found to decrease in the hyperoxaluric rats. Inhibition of ER stress by 4-Phenylbutyric acid prevented the decrease in mitochondria membrane potential and increase in mitochondria calcium observed in hyperoxaluric rats. Also, it restored the protein expression of the sigma-1 receptor protein. On the other hand, N-acetyl cysteine had a nominal impact on the reduction of the ER stress-induced mitochondrial dysfunction. In conclusion, our data showed that hyperoxaluria induces renal ER stress which triggers mitochondria dysfunction, might be via alteration in the sigma-1 receptor protein in the mitochondria-associated ER membranes, which leads to apoptosis, renal injury, and calcium oxalate crystal deposition.

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.

MCT4 Promotes Tumor Malignancy in F98 Glioma Cells

Monocarboxylate transporter 4 (MCT4, SLC16A3) is elevated under hypoxic conditions in many malignant tumors including gliomas. Moreover, MCT4 expression is associated with shorter overall survival. However, the functional consequences of MCT4 expression on the distinct hallmarks of cancer have not yet been explored at the cellular level. Here, we investigated the impact of MCT4 overexpression on proliferation, survival, cell death, migration, invasion, and angiogenesis in F98 glioma cells. Stable F98 glioma cell lines with MCT4 overexpression, normal expression, and knockdown were generated. Distinct hallmarks of cancer were examined using in silico analysis, various in vitro cell culture assays, and ex vivo organotypic rat brain slice culture model. Consistent with its function as lactate and proton exporter, MCT4 expression levels correlated inversely with extracellular pH and proportionally with extracellular lactate concentrations. Our results further indicate that MCT4 promotes proliferation and survival by altered cell cycle regulation and cell death mechanisms. Moreover, MCT4 overexpression enhances cell migration and invasiveness via reorganization of the actin cytoskeleton. Finally, MCT4 inhibition mitigates the induction of angiogenesis, suggesting that MCT4 also plays a crucial role in tumor-related angiogenesis. In summary, our data highlight MCT4/SLC16A3 as a key gene for distinct hallmarks of tumor malignancy in glioma cells.

Synergistic Antitumor Activity of Gramicidin/Lipophilic Bismuth Nanoparticles (BisBAL NPs) on Human Cervical Tumor Cells

The objective of this study was to study the synergistic antitumor effect of lipophilic bismuth nanoparticles (BisBAL NPs) with the antibiotic solution Neo-Poly gramicidin on human cervical tumor cells. The effect of BisBAL NPs and Neo-Poly gramicidin solution on cervical cancer cell line (HeLa) was determined by the MTT cell viability assay and fluorescence microscopy. After a 24-h exposure to 0.1× Neo-Poly gramicidin HeLa cell growth decreased 94%. Fluorescence microscopy confirmed the antitumor effect cell death was higher among treated than among non-treated cells cells. Individually, gramicidin (0.04 mg/mL) inhibited HeLa tumor cell growth most (40%), and neomycin (0.04 mg/mL) least (21%). Gramicidin (0.3 mg/mL) in combination with different concentrations (1–150 μM) of BisBAL NPs had a synergistic antitumor effect against HeLa cells, reaching an &lt; 86% tumor growth inhibition. As far as we know, we are the first to describe the antitumor activity of the antibiotic Neo-Poly gramicidin on a human cervical cancer cell line. The action mechanism of gramicidin/BisBAL NP is based on a strong damage on cell membrane and nucleus of tumor cells. A synergistic effect of gramicidin with BisBAL NPs may be useful as an alternative therapy for cervical cancer patients.

Ceritinib increases sensitivity of AKT inhibitors to gastric cancer

Gastric cancer (GC), known for high morbidity and mortality, is poorly prognosed with traditional chemotherapy and biological agents. Current studies have found that over-activation of AKT is a common molecular characteristic in GC. Although the development of this targeted inhibitor has entered clinical phases, limited success is reported because of its compensatory signaling pathways. Here, we found that GC cell lines with high phosphorylation of AKT show different sensitivity to AKT inhibitors (AKTis), but a reduction of p-GSK3β related sensitivity of AKTis in GC cells. Besides, we revealed that Ceritinib exerted a strongly synergistic antitumor effect with AKT inhibitors both in vitro and in vivo. Obviously, Ceritinib improved the sensitivity of Capivasertib (AZD5363, AKTs) and Afuresertib (GSK2110183, AKTis) in gastric cancer cells, as illustrated by a significant reduction in the GC cell proliferation and enhanced apoptosis. The drug combination showed tumor regression in BALB/c (nu/nu) mouse MKN45 (Gastric cancer), tumor model. Also, the combination strategy indicated significantly low p-AKT levels due to AKTis compensation and reduced the levels of p-GSK3β in both GC cell lines and GC patient-derived cells. These findings may provide a novel combination strategy for gastric cancer treatment.

Nifuroxazide as JAK2 inhibitor: A binding mode proposal and Hel cell proliferation assay

Nifuroxazide has been employed as an anti-diarrheic agent since 1966, but in the last decade has brought to the research spotlight again due to its recently described antitumoral activity through the JAK2 inhibitory potential. Since 2008, more than 70 papers have been published about the issue and more are expected to the following years. Herein we discuss the findings of molecular modelling studies which were performed to elucidate the potential binding mode of this drug into the JAK2 ATP recognition site and also into the allosteric region near the catalytic site. Molecular modelling followed by dynamics simulations indicated the NFZ could bind at both sites, such as a Type II kinase inhibitor since residues from both ATP and modulatory site would exhibit contacts with the drug when in a stable complex. Synthesis of NFZ and its sulfur bioisosteric analogue GPQF-63 were performed and experimental assays against HEL cells indicate the potential of NFZ and, mainly of its analogue GPQF-63 in acting as inhibitors of cell growth. HEL-cells present the JAK2 V617F mutation which leads to an enhanced JAK/STAT pathway and they have never been tested by the NFZ activity before. A mechanistic approach was also performed and revealed that both compounds induce cell apoptosis.Taken together, both the theoretical and experimental approaches point out the N-acylhydrazones as good starting points in the search for JAK2 modulatory small molecules which could then, be studied as promising leads toward new alternatives to control the JAK-STAT pathway related pathologies. This is the first study, as far as we have known, to propose a potential binding mode for NFZ as well as reporting the activity of this drug against HEL cells, which are a usual cellular model to human erythroleukemia and other myeloproliferative diseases.

Designing and Formulation Optimization of Hyaluronic Acid Conjugated PLGA Nanoparticles of Tamoxifen for Tumor Targeting

BACKGROUND

Tamoxifen is widely used for the treatment of estrogen receptor-positive breast cancer. However, it is associated with severe side effects of cancerous proliferation on the uterus endometrium. The tumor-targeting formulation strategies can effectively overcome drug side effects of tamoxifen and provide safer drug treatment.

OBJECTIVE

This study aimed to design tumor-targeted PLGA nanoparticles of tamoxifen by attaching hyaluronic acid (HA) as a ligand to actively target the CD44 receptors present at breast cancer cells surface.

METHODS

PLGA-PEG-HA conjugate was synthesized in the laboratory, and its tamoxifen-loaded nanoparticles were fabricated and characterized by FTIR, NMR, DSC, and XRD analysis. Formulation optimization was done by Box-Behnken design using Design-Expert software. The formulations were evaluated for in vitro drug release and cytotoxic effect on MCF-7 cell lines.

RESULTS

The particle size, PDI, and drug encapsulation efficiency of optimized nanoparticles were 294.8, 0.626, and 65.16%, respectively. Optimized formulation showed 9.56% burst release and sustained drug release for 8h. The drug release was affected by non-Fickian diffusion process and supplemented further by the erosion of polymeric matrix which followed the Korsmeyer-Peppas model. MTT cell line assay showed 47.48% cell mortality when treated with tamoxifen-loaded PLGA- PEG-HA nanoparticles.

CONCLUSION

Hyaluronic acid conjugated PLGA-PEG nanoparticles of tamoxifen were designed for active targeting to cancerous breast cells. The results of the MTT assay showed that tamoxifen nanoparticles formulation was more cytotoxic than tamoxifen drug alone, which is attributed to their preferential uptake by cell lines by the affinity of CD44 receptors of cell lines to HA ligand present in nanoparticles.

Abbreviations for dyes, stains and fluorescent probes used in biology and medicine in the 21st century. A bright future or the last gasp?

I summarize here the history of the use of abbreviations, mostly in subject areas related to dyes, stains and fluorescent probes used in biology and medicine. The dozen most popular abbreviations in these fields are identified and their salient characteristics noted. The pros and cons of each abbreviation are discussed with relevant citations. Certain abbreviations that are not in the list, e.g., AZAN and LN, are mentioned because they have an unusual origin; while others, i.e., INEPT and INADEQUATE are presented because they are bizarre. A related topic is abbreviations used for citations, which require further efforts to decipher. In the past, brevity helped conserve materials, such as ink and paper, and promoted more rapid publishing. I suggest that the use of many abbreviations in the current era of electronic publishing may not be necessary.

Antioxidant/pro-oxidant and antiproliferative activities of phenolic-rich foods and extracts: A cell-based point of view

Phenolic compounds have demonstrated several in vitro beneficial properties by acting as antioxidant and pro-oxidant agents. This chapter approaches the relationship among oxidative stress, cancer, phenolic compounds and antiproliferative activity. Moreover, it discusses in vitro techniques and their biological applications, regarding cell viability and intracellular measure of reactive oxygen assays. The in vitro methods are important tools for screening and understanding the pathways involved on antiproliferative and antioxidant/pro-oxidant effects of phenolic compounds. These findings open avenues for the development of innovative food, chemical structures, technological applications and future perspectives in this research field.

Alternative approaches to overcome chemoresistance to apoptosis in cancer

Apoptosis, or programmed cell death, is a form of regulated cell death (RCD) that is essential for organogenesis and homeostatic maintenance of normal cell populations. Apoptotic stimuli activate the intrinsic and/or extrinsic pathways to induce cell death due to perturbations in the intracellular and extracellular microenvironments, respectively. In patients with cancer, the induction of apoptosis by anticancer drugs and radiation can produce cancer cell death. However, tumor cells can adapt and become refractory to apoptosis-inducing therapies, resulting in the development of clinical resistance to apoptosis. Drug resistance facilitates the development of aggressive primary tumors that eventually metastasize, leading to therapy failure and mortality. To overcome the resistance to apoptosis to neoadjuvant chemotherapy or targeted therapy, alternative targets of RCD can be induced in apoptosis-resistant cancer cells. Alternatively, cell death can be independent of apoptosis and this strategy could be utilized to develop novel anti-cancer therapies. This chapter discusses approaches that could be employed to overcome clinical resistance to apoptosis in cancer cells.

Angiogenesis Is Differentially Modulated by Platelet-Derived Products

Platelet-derived preparations are being used in clinic for their role in tissue repair and regenerative processes. The release of platelet-derived products such as autologous growth factors, cytokines and chemokines can trigger therapeutic angiogenesis. In this in vitro study, we evaluated and compared the ability of three platelet-derived preparations: platelet-rich-plasma (PRP), PRP-hyaluronic acid (PRP-HA) and platelet lysates (PL) at various concentrations (5–40%) to modulate human umbilical vein endothelial cells (HUVEC) biological effects on metabolism, viability, senescence, angiogenic factors secretion and angiogenic capacities in 2D (endothelial tube formation assay or EFTA) and in 3D (fibrin bead assay or FBA). HUVEC exocytosis was stimulated with PRP and PRP-HA. Cell viability was strongly increased by PRP and PRP-HA but mildly by PL. The three preparations inhibit HUVEC tube formation on Matrigel, while PRP enhanced the complexity of the network. In the fibrin bead assay (FBA), PRP and PRP-HA stimulated all steps of the angiogenic process resulting in massive sprouting of a branched microvessel network, while PL showed a weaker angiogenic response. Secretome profiling revealed modulation of 26 human angiogenic proteins upon treatment with the platelet derived preparations. These in vitro experiments suggest that PRP and PRP-HA are effective biological therapeutic tools when sustained therapeutic angiogenesis is needed.

Comparison of the Efficacy of Two Novel Antitubercular Agents in Free and Liposome-Encapsulated Formulations

Tuberculosis is one of the top ten causes of death worldwide, and due to the appearance of drug-resistant strains, the development of new antituberculotic agents is a pressing challenge. Employing an in silico docking method, two coumaran (2,3-dihydrobenzofuran) derivatives-TB501 and TB515-were determined, with promising in vitro antimycobacterial activity. To enhance their effectiveness and reduce their cytotoxicity, we used liposomal drug carrier systems. Two types of small unilamellar vesicles (SUV) were prepared: multicomponent pH-sensitive stealth liposome (SUVmixed) and monocomponent conventional liposome. The long-term stability of our vesicles was obtained by the examination of particle size distribution with dynamic light scattering. Encapsulation efficiency (EE) of the two drugs was determined from absorption spectra before and after size exclusion chromatography. Cellular uptake and cytotoxicity were determined on human MonoMac-6 cells by flow cytometry. The antitubercular effect was characterized by the enumeration of colony-forming units on Mycobacterium tuberculosis H37Rv infected MonoMac-6 cultures. We found that SUVmixed + TB515 has the best long-term stability. TB515 has much higher EE in both types of SUVs. Cellular uptake for native TB501 is extremely low, but if it is encapsulated in SUVmixed it appreciably increases; in the case of TB515, quasi total uptake is accessible. It is concluded that SUVmixed + TB501 seems to be the most efficacious antitubercular formulation given the presented experiments; to find the most promising antituberculotic formulation for therapy further in vivo investigations are needed.

Neurotoxic and convulsant effects induced by jack bean ureases on the mammalian nervous system

Ureases are microbial virulence factors either because of the enzymatic release of ammonia or due to many other non-enzymatic effects. Here we studied two neurotoxic urease isoforms, Canatoxin (CNTX) and Jack Bean Urease (JBU), produced by the plant Canavalia ensiformis, whose mechanisms of action remain elusive. The neurotoxins provoke convulsions in rodents (LD₅₀ ∼2 mg/kg) and stimulate exocytosis in cell models, affecting intracellular calcium levels. Here, electrophysiological and brain imaging techniques were applied to elucidate their mode of action. While systemic administration of the toxins causes tonic-clonic seizures in rodents, JBU injected into rat hippocampus induced spike-wave discharges similar to absence-like seizures. JBU reduced the amplitude of compound action potential from mouse sciatic nerve in a tetrodotoxin-insensitive manner. Hippocampal slices from CNTX-injected animals or slices treated in vitro with JBU failed to induce long term potentiation upon tetanic stimulation. Rat cortical synaptosomes treated with JBU released L-glutamate. JBU increased the intracellular calcium levels and spontaneous firing rate in rat hippocampus neurons. MicroPET scans of CNTX-injected rats revealed increased ^[18]Fluoro-deoxyglucose uptake in epileptogenesis-related areas like hippocampus and thalamus. Curiously, CNTX did not affect voltage-gated sodium, calcium or potassium channels currents, neither did it interfere on cholinergic receptors, suggesting an indirect mode of action that could be related to the ureases' membrane-disturbing properties. Understanding the neurotoxic mode of action of C. ensiformis ureases could help to unveil the so far underappreciated relevance of these toxins in diseases caused by urease-producing microorganisms, in which the human central nervous system is affected.

Copper Dependent Modulation of α-Synuclein Phosphorylation in Differentiated SHSY5Y Neuroblastoma Cells

Copper (Cu) dyshomeostasis plays a pivotal role in several neuropathologies, such as Parkinson's disease (PD). Metal accumulation in the central nervous system (CNS) could result in loss-of-function of proteins involved in Cu metabolism and redox cycling, generating reactive oxygen species (ROS). Moreover, neurodegenerative disorders imply the presence of an excess of misfolded proteins known to lead to neuronal damage. In PD, Cu accumulates in the brain, binds α-synuclein, and initiates its aggregation. We assessed the correlation between neuronal differentiation, Cu homeostasis regulation, and α-synuclein phosphorylation. At this purpose, we used differentiated SHSY5Y neuroblastoma cells to reproduce some of the characteristics of the dopaminergic neurons. Here, we reported that differentiated cells expressed a significantly higher amount of a copper transporter protein 1 (CTR1), increasing the copper uptake. Cells also showed a significantly more phosphorylated form of α-synuclein, further increased by copper treatment, without modifications in α-synuclein levels. This effect depended on the upregulation of the polo-like kinase 2 (PLK2), whereas the levels of the relative protein phosphatase 2A (PP2A) remained unvaried. No changes in the oxidative state of the cells were identified. The Cu dependent alteration of α-synuclein phosphorylation pattern might potentially offer new opportunities for clinical intervention.

Total Synthesis, Structure Revision, and Neuroprotective Effect of Hericenones C-H and Their Derivatives

The first total syntheses of hericenones C-H and "putative 3-hydroxyhericenone F" were achieved. Highlights of the synthesis include the straightforward construction of the resorcinol core and geranyl side chain, assembly of the natural product skeleton by sequential O-geranylation and a clay/zeolite-mediated O → C rearrangement reaction, and a biomimetic cyclization to form a variety of bicyclic natural hericenones and their congeners. The structure of the "putative 3-hydroxyhericenone F" was revised as the 5-exo cyclization product (named: hericenone Z) of epoxyhericenone C through in-depth analyses of the cyclization modes in addition to NMR spectroscopic studies. To gain insights into the biological functions of geranyl-resorcinols in Hericium erinaceus, potential neuroprotective effects against endoplasmic reticulum (ER) stress-dependent cell death were evaluated systematically to clarify a fundamental structure-activity relationship. Among the compounds assayed, the linoleate-containing hericenone analogue, i.e., the regioisomer of hericene D, was found to possess the most potent neuroprotective effect against tunicamycin and thapsigargin-induced ER stress-dependent cell death.

Effect of strontium substitution on structural, sinterability, physicomechanical and biological properties of akermanite ceramic

Despite the excellent in vitro and in vivo performance of akermanite ceramic, its poor toughness and strength limit the biomedical application, particularly under load. Herein, the incorporation of strontium enhanced the physicomechanical properties of akermanite and this is ascribed to the decrease in grain size and better sinterability. To investigate the biological performance, the bone-cell interaction with sintered pellets was assessed by in vitro biocompatibility with human fetal osteoblast cell (hFOB). The cell viability using MTT assay revealed that the Ca_1.9Sr_0.1MgSi₂O₇ pellets with finer grain size provided better interaction between the cells compared to the unsubstituted counterpart with larger grain size. Our findings highlighted that the synergistic effect of controlled degradation rate and release of Sr²⁺ into the medium enhanced the in vitro biological properties of akermanite-based materials.

Anti-proliferative and apoptosis induction activities of curcumin on Leishmania major

Leishmaniasis is a major vector-borne disease triggered by an obligate intracellular protozoan parasite of the genus Leishmania and transmitted by the bite of phlebotomine female sand flies. This parasite causes a wide range of human diseases, from localized self-healing cutaneous lesions to fatal visceral infections. The aim of this study was to investigate the cytotoxic, antiproliferative, and apoptotic effects of curcumin on Leishmania major promastigotes (MHOM/SA/84/JISH) and to assess these effects on the cell cycle of promastigotes. The MTT colorimetric assay was used to evaluate the cytotoxicity and proliferation of promastigotes. Additionally, flow cytometry was used to analyze the cell cycle. The Annexin V/propidium iodide staining technique followed by flow cytometry was used to study the cell death induced by curcumin. In this study curcumin showed a potent antileishmanial effect, exhibiting cytotoxicity against L. major promastigotes. At 80μM, the survival in curcumin treated promastigotes reached 22%; however, the median lethal concentration of curcumin (LC₅₀) was 35μM. The drug exerted its cytotoxic effect by inducing apoptosis. Curcumin-induced cell death in promastigotes reached 82.5% at 80μM concentration. In addition, curcumin delayed the cell cycle in the S-phase inhibiting cell proliferation. Thus, curcumin was shown to be effective against L. major promastigotes. Therefore, curcumin merits further research studies to demonstrate its efficacy in treating cutaneous leishmaniasis.

Aluminium adjuvants in vaccines - A way to modulate the immune response

Aluminium salts have been used as adjuvants in vaccines for almost a century, but still no clear understanding of the mechanisms behind the immune stimulating properties of aluminium based adjuvants is recognized. Aluminium adjuvants consist of aggregates and upon administration of a vaccine, the aggregates will be recognized and phagocytosed by sentinel cells such as macrophages or dendritic cells. The adjuvant aggregates will persist intracellularly, maintaining a saturated intracellular concentration of aluminium ions over an extended time. Macrophages and dendritic cells are pivotal cells of the innate immune system, linking the innate and adaptive immune systems, and become inflammatory and antigen-presenting upon activation, thus mediating the initiation of the adaptive immune system. Both types of cell are highly adaptable, and this review will discuss and highlight how the occurrence of intracellular aluminium ions over an extended time may induce the polarization of macrophages into inflammatory and antigen presenting M1 macrophages by affecting the: endosomal pH; formation of reactive oxygen species (ROS); stability of the phagosomal membrane; release of damage associated molecular patterns (DAMPs); and metabolism (metabolic re-programming). This review emphasizes that a persistent intracellular presence of aluminium ions over an extended time has the potential to affect the functionality of sentinel cells of the innate immune system, inducing polarization and activation. The immune stimulating properties of aluminium adjuvants is presumably mediated by several discrete events, however, a persistent intracellular presence of aluminium ions appears to be a key factor regarding the immune stimulating properties of aluminium based adjuvants.

Synthesis and in vitro study of nitro- and methoxy-2-phenylbenzofurans as human monoamine oxidase inhibitors

A new series of 2-phenylbenzofuran derivatives were designed and synthesized to determine relevant structural features for the MAO inhibitory activity and selectivity. Methoxy substituents were introduced in the 2-phenyl ring, whereas the benzofuran moiety was not substituted or substituted at the positions 5 or 7 with a nitro group. Substitution patterns on both the phenyl ring and the benzofuran moiety determine the affinity for MAO-A or MAO-B. The 2-(3-methoxyphenyl)-5-nitrobenzofuran 9 was the most potent MAO-B inhibitor (IC₅₀ = 0.024 µM) identified in this series, whereas 7-nitro-2-phenylbenzofuran 7 was the most potent MAO-A inhibitor (IC₅₀ = 0.168 µM), both acting as reversible inhibitors. The number and position of the methoxyl groups on the 2-phenyl ring, have an important influence on the inhibitory activity. Molecular docking studies confirmed the experimental results and highlighted the importance of key residues in enzyme inhibition.

Quantitative evaluation of human sperm viability using MTT assay: A laboratory study

Background

3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyl tetrazolium bromide (MTT) assay which evaluates cellular mitochondrial activity is widely used for the assessment of cell proliferation and viability.

Objective

This study was performed to assess human sperm viability using MTT assay.

Materials and Methods

In this laboratory study, human-ejaculated semen samples (n = 56 from different donors) were used. The sperm viability was determined using quantitative MTT assay and the sperm motility was assessed according to World Health Organization guidelines. Sperm viability and the correlation between sperm viability and motility were analyzed.

Results

Data revealed a marked positive correlation between MTT reduction rate and the percentage of viable spermatozoa. The Pearson's correlation coefficients also showed a significant correlation between sperm viability and motility.

Conclusion

MTT assay which is based on mitochondrial functionality is a reliable method for evaluating human sperm viability and could be used as a diagnostic test for predicting sperm fertilization ability in clinical settings.

Formulation of Topical Dosage Forms Containing Synthetic and Natural Anti-Inflammatory Agents for the Treatment of Rheumatoid Arthritis

Topical anti-inflammatory and analgesic effect for the treatment of rheumatoid arthritis is of major interest because of their fewer side effects compared to oral therapy. The purpose of this study was to prepare different types of topical formulations (ointments and gels) containing synthetic and natural anti-inflammatory agents with different excipients (e.g.,: surfactants, gel-forming) for the treatment of rheumatoid arthritis. The combination of Non-Steroidal Anti-Inflammatory Drugs (NSAIDs), diclofenac sodium, a topical analgesic agent methyl salicylate, and a lyophilized extract of Calendula officinalis with antioxidant effect were used in our formulations. The aim was to select the appropriate excipients and dosage form for the formulation in order to enhance the diffusion of active substances and to certify the antioxidant, analgesic, and anti-inflammatory effects of these formulations. To characterize the physicochemical properties of the formulations, rheological studies, and texture profile analysis were carried out. Membrane diffusion and permeability studies were performed with Franz-diffusion method. The therapeutic properties of the formulations have been proven by an antioxidant assay and a randomized prospective study that was carried out on 115 patients with rheumatoid arthritis. The results showed that the treatment with the gel containing diclofenac sodium, methyl salicylate, and lyophilized Calendula officinalis as active ingredients, 2-propenoic acid homopolymer (Synthalen K) as gel-forming excipient, distilled water, triethanolamine, and glycerol had a beneficial analgesic and local anti-inflammatory effect.

Anti-glioblastoma Activity of Kaempferol via Programmed Cell Death Induction: Involvement of Autophagy and Pyroptosis

Glioblastoma is one of the most common and lethal intracranial malignant, and is still lack of ideal treatments. Kaempferol is a major nutrient found in various edible plants, which has exhibited the potential for the treatment of glioblastoma. However, the specific anti-glioma mechanism of kaempferol is yet to be studied. Herein, we aim to explore the mechanisms underlying the anti-glioma activity of kaempferol. Our results demonstrated that kaempferol suppresses glioma cell proliferation in vitro and inhibits tumor growth in vivo. Moreover, kaempferol raises ROS and decreases mitochondrial membrane potential in glioma cells. The high levels of ROS induce autophagy then ultimately trigger the pyroptosis of glioma cells. Interestingly, when we used 3-MA to inhibit autophagy, we found that the cleaved form of GSDME was also decreased, suggesting that kaempferol induces pyroptosis through regulating autophagy in glioma cells. In conclusion, this study revealed kaempferol possesses good anti-glioma activity by inducing ROS, and subsequently leads to autophagy and pyroptosis, highlighting its clinical potentials as a natural nutrient against glioblastoma.

Old Polyanionic Drug Suramin Suppresses Detrimental Cytotoxicity of the Host Defense Peptide LL-37

The host defense peptide LL-37 is the only human cathelicidin, characterized by pleiotropic activity ranging from immunological to anti-neoplastic functions. However, its overexpression has been associated with harmful inflammatory responses and apoptosis. Thus, for the latter cases, the development of strategies aiming to reduce LL-37 toxicity is highly desired as these have the potential to provide a viable solution. Here, we demonstrate that the reduction of LL-37 toxicity might be achieved by the impairment of its cell surface binding through interaction with small organic compounds that are able to alter the peptide conformation and minimize its cell penetration ability. In this regard, the performed cell viability and internalization studies showed a remarkable attenuation of LL-37 cytotoxicity toward colon and monocytic cells in the presence of the polysulfonated drug suramin. The mechanistic examinations of the molecular details indicated that this effect was coupled with the ability of suramin to alter LL-37 secondary structure via the formation of peptide-drug complexes. Moreover, a comparison with other therapeutic agents having common features unveiled the peculiar ability of suramin to optimize the binding to the peptide sequence. The newly discovered suramin action is hoped to inspire the elaboration of novel repurposing strategies aimed to reduce LL-37 cytotoxicity under pathological conditions.

Formulation of Creams Containing Spirulina Platensis Powder with Different Nonionic Surfactants for the Treatment of Acne Vulgaris

Natural products used in the treatment of acne vulgaris may be promising alternative therapies with fewer side effects and without antibiotic resistance. The objective of this study was to formulate creams containing Spirulina (Arthrospira) platensis to be used in acne therapy. Spirulina platensis belongs to the group of micro algae and contains valuable active ingredients. The aim was to select the appropriate nonionic surfactants for the formulations in order to enhance the diffusion of the active substance and to certify the antioxidant and antibacterial activity of Spirulina platensis-containing creams. Lyophilized Spirulina platensis powder (SPP) was dissolved in Transcutol HP (TC) and different types of nonionic surfactants (Polysorbate 60 (P60), Cremophor A6:A25 (CR) (1:1), Tefose 63 (TFS), or sucrose ester SP 70 (SP70)) were incorporated in creams as emulsifying agents. The drug release was evaluated by the Franz diffusion method and biocompatibility was tested on HaCaT cells. In vitro antioxidant assays were also performed, and superoxide dismutase (SOD) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) assays were executed. Antimicrobial activities of the selected compositions were checked against Staphylococcus aureus (S. aureus) and Cutibacteriumacnes (C. acnes) (formerly Propionibacterium acnes) with the broth microdilution method. Formulations containing SP 70 surfactant with TC showed the most favorable dissolution profiles and were found to be nontoxic. This composition also showed significant increase in free radical scavenger activity compared to the blank sample and the highest SOD enzyme activity was also detected after treatment with the cream samples. In antibacterial studies, significant differences were observed between the treated and control groups after an incubation time of 6 h.

Salmonella-innovative targeting carrier: Loading with doxorubicin for cancer treatment

Cell- based targeted delivery is recently gain attention as a promising platform for delivery of anticancer drug in selective and efficient manner. As a new biotechnology platform, bacterial ghosts (BGs) have novel biomedical application as targeted drug delivery system (TDDS). In the current work, Salmonellas' BGs was utilized for the first time as hepatocellular cancer (HCC) in-vitro targeted delivery system. Successful BGs loading and accurate analysis of doxorubicin (DOX) were necessary steps for testing the applicability of DOX loaded BGs in targeting the liver cancer cells. Loading capacity was maximized to reach 27.5 µg/mg (27.5% encapsulation efficiency), by incubation of 10 mg BGs with 1 mg DOX at pH 9 in constant temperature (25 °C) for 10 min. In-vitro release study of DOX loaded BGs showed a sustained release (182 h) obeying Higuchi sustained kinetic release model. The death rate (tested by MTT assay) of HepG2 reached to 64.5% by using of 4 μg/ml, while it was about 51% using the same concentration of the free DOX (P value < 0.0001 One-way ANOVA analysis). The proliferative inhibitory concentration (IC50) of the DOX combined formula was 1.328 µg/ml that was about one third of the IC50 of the free DOX (3.374 μg/ml). Apoptosis analysis (tested by flow-cytometry) showed more accumulation in early apoptosis (8.3%) and late apoptosis/necrosis (91%) by applying 1 μg/ml BGs combined DOX, while 1 μg/ml free DOX showed 33.4% of cells in early apoptosis and 39.3% in late apoptosis/necrosis, (P value˃ 0.05: one-way ANOVA). In conclusion, DOX loaded Salmonellas' BGs are successfully prepared and tested in vivo with promising potential as hepatocellular cancer (HCC) targeted delivery system.

Possible Pharmacodynamic Interaction of Azelnidipine with Citicoline Against Ischemic Brain Injury: Behavioral, Biochemical and Histological Alterations

BACKGROUND

Currently, no drug has been approved for the management of postischemic neuronal damage. Existing studies show that calcium channel blockers have neuroprotective properties, while citicoline is involved in maintaining neuronal integrity.

PURPOSE

This study was envisaged to investigate the effect of azelnidipine (novel calcium channel blocker) alone and in combination with citicoline (phosphatidyl-choline analogue) against ischemic brain damage in Wistar rats.

METHODS

Previously standardized bilateral common carotid artery occlusion model was used to induce cerebral ischemic injury in Wistar rats. Pretreatment with azelnidipine (1.5 mg/Kg and 3 mg/Kg; p.o.) or citicoline (250 mg/Kg; i.p.) was done every 24 h starting 7 days before the bilateral common carotid artery occlusion surgery. Pharmacological assessments (behavioral, biochemical, mitochondrial, molecular, and histological) were done after 48 h of the reperfusion period.

RESULTS

Azelnidipine and citicoline were found to protect the brain from progressive neuronal damage as seen by improved sensorimotor behavior (locomotion, rota rod, and beam balance performance) and reduced oxidative stress (decreased malondialdehyde (MDA), nitrite, increased glutathione (GSH), superoxide dismutase (SOD)). Impairment of mitochondrial enzyme system and increase in the infarct area were found to be arrested by individual treatments with azelnidipine and citicoline. These effects were further potentiated synergistically as the combination of citicoline and azelnidipine was found to decrease glutamate levels, caspase-3 activity and histological alterations as compared to their individual effects.

CONCLUSION

Azelnidipine and citicoline synergistically decrease excitotoxic and oxidative damage against ischemic brain injury in Wistar rats and, therefore, propose a clinically relevant combination for the prevention of postischemic neuronal damage.

Synthesis and biological evaluation of 2'-Aminochalcone: A multi-target approach to find drug candidates to treat Alzheimer's disease

Alzheimer's disease (AD) is a neurodegenerative process that compromises cognitive functions. The physiopathology of AD is multifactorial and is mainly supported by the cholinergic and amyloid hypotheses, which allows the identification the fundamental role of some markers, such as the enzymes acetylcholinesterase (AChE) and β-secretase (BACE-1), and the β-amyloid peptide (Aβ). In this work, we prepared a series of chalcones and 2'-aminochalcones, which were tested against AChE and BACE-1 enzymes and on the aggregation of Aβ. All compounds inhibited AChE activity with different potencies. We have found that the majority of chalcones having the amino group are able to inhibit BACE-1, which was not observed for chalcones without this group. The most active compound is the one derived from 2,3-dichlorobenzaldeyde, having an IC₅₀ value of 2.71 μM. A molecular docking study supported this result, showing a good interaction of the amino group with aspartic acid residues of the catalytic diade of BACE-1. Thioflavin-T fluorescence emission is reduced in 30 - 40%, when Aβ₄₂ is incubated in the presence of some chalcones under aggregation conditions. In vitro cytotoxicity and in silico prediction of pharmacokinetic properties were also conducted in this study.

Novel coumarin-pyridazine hybrids as selective MAO-B inhibitors for the Parkinson's disease therapy

The 3-pyridazinylcoumarin scaffold was previously reported as an efficient core for the discovery of reversible and selective inhibitors of MAO-B, a validated drug target for PD therapy which also plays an important role in the AD progress. Looking for its structural optimization, novel compounds of hybrid structure coumarin-pyridazine, differing in polarizability and lipophilicity properties, were synthesized and tested against the two MAO isoforms, MAO-A and MAO-B (compounds 17a-f and 18a-f). All the designed compounds selectively inhibited the MAO-B isoenzyme, exhibiting many of them IC₅₀ values ranging from sub-micromolar to nanomolar grade and lacking neuronal toxicity. The 7-bromo-3-(6-bromopyridazin-3-yl)coumarin (18c), the most potent compound of these series (IC₅₀ = 60 nM), was subjected to further in vivo studies in a reserpine-induced mouse PD model. The obtained results suggest a promising potential for 18c as antiparkinsonian agent. Molecular modeling studies also provided valuable information about the enzyme-drug interactions and the potential pharmacokinetic profile of the novel compounds.

Molecular Physiology and Pathophysiology of Bilirubin Handling by the Blood, Liver, Intestine, and Brain in the Newborn

Bilirubin is the end product of heme catabolism formed during a process that involves oxidation-reduction reactions and conserves iron body stores. Unconjugated hyperbilirubinemia is common in newborn infants, but rare later in life. The basic physiology of bilirubin metabolism, such as production, transport, and excretion, has been well described. However, in the neonate, numerous variables related to nutrition, ethnicity, and genetic variants at several metabolic steps may be superimposed on the normal physiological hyperbilirubinemia that occurs in the first week of life and results in bilirubin levels that may be toxic to the brain. Bilirubin exists in several isomeric forms that differ in their polarities and is considered a physiologically important antioxidant. Here we review the chemistry of the bilirubin molecule and its metabolism in the body with a particular focus on the processes that impact the newborn infant, and how differences relative to older children and adults contribute to the risk of developing both acute and long-term neurological sequelae in the newborn infant. The final section deals with the interplay between the brain and bilirubin and its entry, clearance, and accumulation. We conclude with a discussion of the current state of knowledge regarding the mechanism(s) of bilirubin neurotoxicity.

Undesirable effects of chemical inhibitors of NAD(P)+ transhydrogenase on mitochondrial respiratory function

NAD(P)⁺ transhydrogenase (NNT) is located in the inner mitochondrial membrane and catalyzes a reversible hydride transfer between NAD(H) and NADP(H) that is coupled to proton translocation between the intermembrane space and mitochondrial matrix. NNT activity has an essential role in maintaining the NADPH supply for antioxidant defense and biosynthetic pathways. In the present report, we evaluated the effects of chemical compounds used as inhibitors of NNT over the last five decades, namely, 4-chloro-7-nitrobenzofurazan (NBD-Cl), N,N'-dicyclohexylcarbodiimide (DCC), palmitoyl-CoA, palmitoyl-l-carnitine, and rhein, on NNT activity and mitochondrial respiratory function. Concentrations of these compounds that partially inhibited the forward and reverse NNT reactions in detergent-solubilized mouse liver mitochondria significantly impaired mitochondrial respiratory function, as estimated by ADP-stimulated and nonphosphorylating respiration. Among the tested compounds, NBD-Cl showed the best relationship between NNT inhibition and low impact on respiratory function. Despite this, NBD-Cl concentrations that partially inhibited NNT activity impaired mitochondrial respiratory function and significantly decreased the viability of cultured Nnt^-/- mouse astrocytes. We conclude that even though the tested compounds indeed presented inhibitory effects on NNT activity, at effective concentrations, they cause important undesirable effects on mitochondrial respiratory function and cell viability.

Construction of Inflammatory Directed Polymer Micelles and Its Application in Acute Lung Injury

Currently, there is no specific treatment for acute lung injury (ALI) in clinical practice. In order to efficiently and accurately treat ALI, the advantages of cationic carriers were combined to accelerate the cell uptake. Polycaprolactone-polyethylene glycol carrier (PCL-PEG-COOH, PPC) with good biocompatibility, polycaprolactone-polyethylmethacrylate cationic carrier (PCL-PDMAEMA, PCD), and polycaprolactone-polyethylene glycol carrier connected with high-affinity targeting peptide (Esbp) targeting inflammatory endothelial cells (PCL-PEG-Esbp, PPE) were used to construct the high-molecular polymer micelles (PCD/PPC/PPE). The particle size of the prepared DEX-loaded micelles was 130 ± 4.41 nm, and the Zeta potential was 28.3 ± 0.76 mV. The CMC value of the prepared polymer micelles was 0.643 μg/mL, and it was not easy to depolymerize in the blood circulation. Only about 40% DXM was released from the drug-loaded polymer micelles after 12 h compared with free DXM, indicating that the micelle material had a certain sustained-release performance in vitro release experiments. The safe concentration range of polymer was determined by biocompatibility test. It was recommended that the concentration of polymer micelles should not exceed 0.40 mg/mL to obtain a good compatibility in organisms. The results of cytotoxicity measurement showed that when the content of PCD increased to 50%, the concentration of blank micelles should not exceed 500 μg/mL and the concentration of DXM-loaded micelles should not be higher than 100 μg/mL. It was proved in the cell uptake experiment that the cation carrier of the micelles accelerated the cell uptake. The targeting ability of the targeted micelle group was higher compared with the non-targeted micelle group (P < 0.01, **). Meanwhile, the targeting ability of the non-targeted micelle group was higher compared with the free group (P < 0.001, ***). The targeting ability of the non-targeted micelle group was about 2.30 times and the targeted micelle group was about 3.16 times larger than that of the free group. It was also proved in the in vivo targeting experiments that the targeted micelles had a good targeting ability. The results of in vivo imaging of mice showed that the DXM of the micelle group gathered more in the lungs, and the micelle group had a better targeting ability compared with the free DID group. The order of lung targeting intensity was targeted micelles > non-targeted micelles >> free DID group. The targeting ability of polypeptide Esbp to ALI was confirmed. In conclusion, the prepared PCD/PPC/PPE polymer micelles had obvious in vitro and in vivo targeting ability and good biocompatibility. They could be used as a new targeted delivery system for the treatment of ALI in the future.

D-Pinitol treatment induced the apoptosis in human leukemia MOLT-4 cells by improved apoptotic signaling pathway

Cancer is still remain as a global burden with the 18.1 million and 9.6 million new cases and mortlities, respectively estimated globally. Leukemia may arise at all ages varied from the infants to elders. In this exploration, we planned to evaluate the antiproliferative effect of D-pinitol on human leukemia MOLT-4 cells. Anticancer potential of D-pinitol was examined using MTT assay. Reactive oxygen species (ROS) generation was studied by fluorescence microscopic method using DCFH-DA staining. Apoptotic morphological alterations were determined by dual staining (acridine orange and ethidium bromide). Western blot and ELISA methods were employed to study apoptotic protein expression. D-pinitol treatment significantly induced cytotoxicity in human leukemia MOLT-4 cells. We observed that D-pinitol induces the generation of ROS in MOLT-4 cells. Further, we noticed that D-pinitol significantly induced apoptosis in a dosage dependent manner. Moreover, western blot and ELISA based analysis revealed that D-pinitol elevated the Bax, Caspase-3, Caspase-9 and attenuated the Bcl-2 expression in leukemic cancer cell. Our findings suggest that D-pinitol treatment induces the apoptosis in human leukemic cells by generating intracellular ROS and modulating apoptotic protein expression.

Guanosine Neuroprotective Action in Hippocampal Slices Subjected to Oxygen and Glucose Deprivation Restores ATP Levels, Lactate Release and Glutamate Uptake Impairment: Involvement of Nitric Oxide

Stroke is a major cause of disability and death worldwide. Oxygen and glucose deprivation (OGD) in brain tissue preparations can reproduce several pathological features induced by stroke providing a valuable ex vivo protocol for studying the mechanism of action of neuroprotective agents. Guanosine, an endogenous guanine nucleoside, promotes neuroprotection in vivo and in vitro models of neurotoxicity. We previously showed that guanosine protective effect was mimicked by inhibition of nitric oxide synthases (NOS) activity. This study was designed to investigate the involvement of nitric oxide (NO) in the mechanisms related to the protective role of guanosine in rat hippocampal slices subjected to OGD followed by reoxygenation (OGD/R). Guanosine (100 μM) and the pan-NOS inhibitor, L-NAME (1 mM) afforded protection to hippocampal slices subjected to OGD/R. The presence of NO donors, DETA-NO (800 μM) or SNP (5 μM) increased reactive species production, and abolished the protective effect of guanosine or L-NAME against OGD/R. Guanosine or L-NAME treatment prevented the impaired ATP production, lactate release, and glutamate uptake following OGD/R. The presence of a NO donor also abolished the beneficial effects of guanosine or L-NAME on bioenergetics and glutamate uptake. These results showed, for the first time, that guanosine may regulate cellular bioenergetics in hippocampal slices subjected to OGD/R injury by a mechanism that involves the modulation of NO levels.

Staphylococcus xylosus VITURAJ10: Pyrrolo [1,2α] pyrazine-1,4-dione, hexahydro-3-(2-methylpropyl) (PPDHMP) producing, potential probiotic strain with antibacterial and anticancer activity

In the present study bacterial strain (VITURAJ10), isolated from goat milk was characterised for its probiotic potential. The various probiotic traits included tolerance to acidic pH (up to pH 3), bile salts (0.3%) and transit gut environment (simulated with digestive juices such as pepsin, Oxgall and pancreatin). The isolate could withstand high NaCl concentrations in the growth medium, showed inability to produce hemolysin and did not hydrolyse mucin. VITURAJ10 was capable of forming biofilm and produced exopolysachharide. The bioactive metabolites produced by the isolate were extracted and they showed growth suppressing activity towards pathogenic strains such as Escherichia coli, Salmonella enterica and Staphylococcus aureus. The crude extract was fractionated with solid phase extraction (SPE) chromatography and the fractions 10 and 12 were found to be effective against the bacterial pathogens. The fractions were further gauged for cytotoxic activity against MCF-7 cell line by MTT assay. The biologically significant compounds identified through GC-MS and FT-IR analysis in the fractions were, Actinomycin D, Pyrrolo [1,2α] Pyrazine-1,4-Dione, Hexahydro-3-(2-Methylpropyl)- (PPDHMP) and Didemnin B. The phylogenetic taxonomy of the isolate revealed the isolate to be the closest neighbour of Staphylococcus xylosus VITURAJ10 (GenBank accession no. KX770743.1) as per the16S rRNA gene sequencing and subsequent phylogenetic tree analysis.

Sonic Hedgehog and Triiodothyronine Pathway Interact in Mouse Embryonic Neural Stem Cells

Neural stem cells are fundamental to development of the central nervous system (CNS)-as well as its plasticity and regeneration-and represent a potential tool for neuro transplantation therapy and research. This study is focused on examination of the proliferation dynamic and fate of embryonic neural stem cells (eNSCs) under differentiating conditions. In this work, we analyzed eNSCs differentiating alone and in the presence of sonic hedgehog (SHH) or triiodothyronine (T3) which play an important role in the development of the CNS. We found that inhibition of the SHH pathway and activation of the T3 pathway increased cellular health and survival of differentiating eNSCs. In addition, T3 was able to increase the expression of the gene for the receptor smoothened (Smo), which is part of the SHH signaling cascade, while SHH increased the expression of the T3 receptor beta gene (Thrb). This might be the reason why the combination of SHH and T3 increased the expression of the thyroxine 5-deiodinase type III gene (Dio3), which inhibits T3 activity, which in turn affects cellular health and proliferation activity of eNSCs.

Evaluation of B Cell Proliferation in vivo by EdU Incorporation Assay

Generation of antibodies is crucial for establishing enduring protection from invading pathogens, as well as for maintaining homeostasis with commensal bacteria at mucosal surfaces. Chronic exposure to microbiota- and dietary- derived antigens results in continuous production of antibody producing cells within the Peyer's patch germinal center structures. Recently, we have shown that B cells responding to gut-derived antigens colonize the subepithelial dome (SED) in Peyer's patches and rapidly proliferate independently of their relative BCR affinity. To evaluate B cell proliferation within different niches in Peyer's patches, we applied in vivo EdU incorporation assay as described in this protocol.

Daily fluctuating temperatures decrease growth and reproduction rate of a lethal amphibian fungal pathogen in culture

BACKGROUND

Emerging infectious diseases (EIDs) are contributing to species die-offs worldwide. We can better understand EIDs by using ecological approaches to study pathogen biology. For example, pathogens are exposed to variable temperatures across daily, seasonal, and annual scales. Exposure to temperature fluctuations may reduce pathogen growth and reproduction, which could affect pathogen virulence, transmission, and environmental persistence with implications for disease. We examined the effect of a variable thermal environment on reproductive life history traits of the fungal pathogen Batrachochytrium dendrobatidis (Bd). Bd causes chytridiomycosis, an emerging infectious disease of amphibians. As a pathogen of ectothermic hosts, Bd can be exposed to large temperature fluctuations in nature. To determine the effect of fluctuating temperatures on Bd growth and reproduction, we collected temperature data from breeding pools of the Yosemite toad (Anaxyrus canorus), a federally threatened species that is susceptible to chytridiomycosis. We cultured Bd under a daily fluctuating temperature regime that simulated Yosemite toad breeding pool temperatures and measured Bd growth, reproduction, fecundity, and viability.

RESULTS

We observed decreased Bd growth and reproduction in a diurnally fluctuating thermal environment as compared to cultures grown at constant temperatures within the optimal Bd thermal range. We also found that Bd exhibits temperature-induced trade-offs under constant low and constant high temperature conditions.

CONCLUSIONS

Our results provide novel insights on variable responses of Bd to dynamic thermal conditions and highlight the importance of incorporating realistic temperature fluctuations into investigations of pathogen ecology and EIDs.