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

Fluconazole Represses Cytochrome P450 1B1 and Its Associated Arachidonic Acid Metabolites in the Heart and Protects Against Angiotensin II-Induced Cardiac Hypertrophy

Cytochrome P450 1B1 (CYP1B1) has been reported to have a major role in metabolizing arachidonic acid (AA) into cardiotoxic metabolites, mid-chain hydroxyeicosatetraenoic acids (HETEs). Recently, we have shown that fluconazole decreases the level of mid-chain HETEs in human liver microsomes. Therefore, the objectives of this study were to investigate the effect of fluconazole on CYP1B1 mediated mid-chain HETEs and to explore its potential protective effect against angiotensin II- (Ang II)-induced cellular hypertrophy. To do this, Sprague Dawley rats were injected intraperitoneally with a single dose of fluconazole (20 mg/kg) for 24 h. Also, H9c2 and RL-14 cells were treated with 10 μM Ang II in the presence and absence of 50 μM fluconazole for 24 h. Our results demonstrated that treatment of rats with fluconazole significantly decreased the expression of CYP1B1 enzyme and the level of mid-chain HETEs in the heart. Furthermore, fluconazole was able to attenuate Ang-II-induced cellular hypertrophy as evidenced by a significant down-regulation of hypertrophic markers; β-myosin heavy chain (MHC)/α-MHC and brain natriuretic peptide (BNP) as well as cell surface area. In conclusion, our findings indicate that fluconazole protects against Ang II-induced cellular hypertrophy by repressing CYP1B1 and its associated mid-chain HETEs.

A novel and more efficient biosynthesis approach for human insulin production in Escherichia coli (E. coli)

Insulin has captured researchers' attention worldwide. There is a rapid global rise in the number of diabetic patients, which increases the demand for insulin. Current methods of insulin production are expensive and time-consuming. A PCR-based strategy was employed for the cloning and verification of human insulin. The human insulin protein was then overexpressed in E. coli on a laboratory scale. Thereafter, optimisation of human insulin expression was conducted. The yield of human insulin produced was approximately 520.92 (mg/L), located in the intracellular fraction. Human insulin was detected using the MALDI-TOF-MS and LC-MS methods. The crude biosynthesised protein sequence was verified using protein sequencing, which had a 100% similarity to the human insulin sequence. The biological activity of human insulin was tested in vitro using a MTT assay, which revealed that the crude biosynthesised human insulin displayed a similar degree of efficacy to the standard human insulin. This study eliminated the use of affinity tags since an untagged pET21b expression vector was employed. Tedious protein renaturation, inclusion body recovery steps, and the expensive enzymatic cleavage of the C-peptide of insulin were eliminated, thereby making this method of biosynthesising human insulin a novel and more efficient method.

Anionic food color tartrazine enhances antibacterial efficacy of histatin-derived peptide DHVAR4 by fine-tuning its membrane activity

Here it is demonstrated how some anionic food additives commonly used in our diet, such as tartrazine (TZ), bind to DHVAR4, an antimicrobial peptide (AMP) derived from oral host defense peptides, resulting in significantly fostered toxic activity against both Gram-positive and Gram-negative bacteria, but not against mammalian cells. Biophysical studies on the DHVAR4-TZ interaction indicate that initially large, positively charged aggregates are formed, but in the presence of lipid bilayers, they rather associate with the membrane surface. In contrast to synergistic effects observed for mixed antibacterial compounds, this is a principally different mechanism, where TZ directly acts on the membrane-associated AMP promoting its biologically active helical conformation. Model vesicle studies show that compared to dye-free DHVAR4, peptide-TZ complexes are more prone to form H-bonds with the phosphate ester moiety of the bilayer head-group region resulting in more controlled bilayer fusion mechanism and concerted severe cell damage. AMPs are considered as promising compounds to combat formidable antibiotic-resistant bacterial infections; however, we know very little on their in vivo actions, especially on how they interact with other chemical agents. The current example illustrates how food dyes can modulate AMP activity, which is hoped to inspire improved therapies against microbial infections in the alimentary tract. Results also imply that the structure and function of natural AMPs could be manipulated by small compounds, which may also offer a new strategic concept for the future design of peptide-based antimicrobials.

African and Asian Mitochondrial DNA Haplogroups Confer Resistance Against Diabetic Stresses on Retinal Pigment Epithelial Cybrid Cells In Vitro

Diabetic retinopathy (DR) is the most common cause of blindness for individuals under the age of 65. This loss of vision can be due to ischemia, neovascularization, and/or diabetic macular edema, which are caused by breakdown of the blood-retina barrier at the level of the retinal pigment epithelium (RPE) and inner retinal vasculature. The prevalence of diabetes and its complications differ between Caucasian-Americans and certain minority populations, such as African-Americans and Asian-Americans. Individuals can be classified by their mitochondrial haplogroups, which are collections of single nucleotide polymorphisms (SNPs) in mitochondrial DNA (mtDNA) representing ancient geographic origins of populations. In this study, we compared the responses of diabetic human RPE cybrids, cell lines containing identical nuclei but mitochondria from either European (maternal European) or maternal African or Asian individuals, to hypoxia and high glucose levels. The African and Asian diabetic ([Afr+Asi]/DM) cybrids showed (1) resistance to both hyperglycemic and hypoxic stresses; (2) downregulation of pro-apoptotic indicator BAX; (3) upregulation of DNA methylation genes, such as DNMT3A and DNMT3B; and (4) resistance to DNA demethylation by the methylation inhibitor 5-Aza-2'-deoxycytidine (5-Aza-dC) compared to European diabetic (Euro/DM) cybrids. Our findings suggest that mitochondria from African and Asian diabetic subjects possess a "metabolic memory" that confers resistance against hyperglycemia, hypoxia, and demethylation, and that this "metabolic memory" can be transferred into the RPE cybrid cell lines in vitro.

Evaluation of Cytotoxicity of Self-Emulsifying Formulations Containing Long-Chain Lipids Using Caco-2 Cell Model: Superior Safety Profile Compared to Medium-Chain Lipids

Medium-chain (MC) and long-chain (LC) lipids are used for development of self-emulsifying drug delivery systems (SEDDS). MC lipids are often preferred because of their ability to form stable microemulsions with relatively high drug solubilization capacity. On the other hand, LC lipids could be more biocompatible as most endogenous and dietary lipids are LC glycerides. They also maintain high drug solubilization capacity after digestion. The present study was undertaken to determine the cytotoxicity of LC lipids and their formulations on Caco-2 cells of 1-day, 5-day, and 21-day maturity. The results were compared with the cytotoxicity profiles of MC lipids reported previously from our laboratory. The cell viability and cell membrane integrity were, respectively, determined using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and the lactate dehydrogenase assay. The cytotoxicity was partially due to lipid surfactant-induced membrane rupture, and it was influenced by cell maturity and formulation composition. The lipid-surfactant combinations showed greater tolerance than surfactants alone, and LC-SEDDS were well-tolerated at almost 10-fold higher concentration than corresponding MC-SEDDS. Furthermore, the cytotoxicity of digestion end products of both LC and MC triglycerides in the presence of 3 mM sodium taurocholate was compared on 21-day Caco-2 cultures by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. The LC lipid formulations showed better tolerance than MC lipid formulations after digestion. Thus, although MC and LC lipids are well-tolerated at doses normally administered to humans, LC lipids show much better safety than MC lipids in a cell-culture model.

Bevacizumab as a monoclonal antibody inhibits mitochondrial complex II in isolated rat heart mitochondria: ameliorative effect of ellagic acid

Drug-induced cardiotoxicity usually manifests as heart failure or left ventricular systolic dysfunction. Left ventricular dysfunction is a rarely reported side effect of bevacizumab (BEV) with an incidence of 1.2%, and this occurs irrespective of the route of administration. In this study, we focused on an analysis of BEV effects on mitochondrial complexes activities and protective effect of ellagic acid (EA) against BEV-induced mitochondria toxicity. Rat heart mitochondria were isolated using differential centrifugation form wistar rats. Using biochemical and flowcytometry assays we evaluated mitochondrial complexes activity, succinate dehydrogenases (SDH), mitochondrial swelling, reactive oxygen species (ROS) formation and mitochondrial membrane potential (MMP) in isolated mitochondria. We observed only decreased activity of complexes II after exposure with BEV (50 and 100 µg/ml). The inhibition of complex II is paralleled by the decreased MMP, mitochondrial swelling, and ROS formation. Also, we showed that EA (10-100 µM) as an antioxidant and natural agent significantly decreases mitochondrial toxicity induced by BEV. Together, for the first time, this preliminary study has demonstrated a significant decrease in activity of complexes II after exposure with BEV and proved the protective effects of EA in alleviating BEV-mediated mitochondria toxicity.

Carvacrol and Thymol Attenuate Cytotoxicity Induced by Amyloid β25-35 via Activating Protein Kinase C and Inhibiting Oxidative Stress in PC12 Cells

Background

Our previous findings indicated that carvacrol and thymol alleviate cognitive impairments caused by Aβ in rodent models of Alzheimer's disease (AD). In this study, the neuroprotective effects of carvacrol and thymol against Aβ25-35-induced cytotoxicity were evaluated, and the potential mechanisms were determined.

Methods

PC12 cells were pretreated with Aβ25-35 for 2 h, followed by incubation with carvacrol or thymol for additional 48 h. Cell viability was measured by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide method. A flurospectrophotometer was employed to observe the intracellular reactive oxygen species (ROS) production. Protein kinase C (PKC) activity was analyzed using ELISA.

Results

Our results indicated that carvacrol and thymol could significantly protect PC12 cells against Aβ25-35-induced cytotoxicity. Furthermore, Aβ25-35 could induce intracellular ROS production, while carvacrol and thymol could reverse this effect. Moreover, our findings showed that carvacrol and thymol elevate PKC activity similar to Bryostatin-1, as a PKC activator.

Conclusion

This study provided the evidence regarding the protective effects of carvacrol and thymol against Aβ25–35-induced cytotoxicity in PC12 cells. The results suggested that the neuroprotective effects of these compounds against Aβ25-35 might be through attenuating oxidative damage and increasing the activity of PKC as a memory-related protein. Thus, carvacrol and thymol were found to have therapeutic potential in preventing or modulating AD.

Encapsulation of ε-viniferin in onion-type multi-lamellar liposomes increases its solubility and its photo-stability and decreases its cytotoxicity on Caco-2 intestinal cells

ε-Viniferin, a resveratrol dimer, is a naturally occurring stilbene that has been studied so far for its potential beneficial effects on human health. Its low water solubility, its photo-sensitivity and its low bioavailability make its applications in the food industry complicated. To overcome these limitations, ε-viniferin was encapsulated in phospholipid-based multi-lamellar liposomes (MLLs) called spherulites or onions. In the best case, an encapsulation efficiency of 58 ± 3% and a bioactive loading of 4.2 ± 0.5% were reached. Encapsulation of ε-viniferin drastically increased its water solubility by more than 5 orders to reach 17.4 g L-1 and provided protection against its UV-induced isomerization. While ε-viniferin was shown to be significantly toxic to Caco-2 intestinal-like cells for concentrations higher than 25 μM, once encapsulated in MLLs, those cells did not experience any mortality even for the highest tested stilbene concentration (100 μM) as revealed by red neutral assay.

Adenosine A1-A2A Receptor-Receptor Interaction: Contribution to Guanosine-Mediated Effects

Guanosine, a guanine-based purine nucleoside, has been described as a neuromodulator that exerts neuroprotective effects in animal and cellular ischemia models. However, guanosine's exact mechanism of action and molecular targets have not yet been identified. Here, we aimed to elucidate a role of adenosine receptors (ARs) in mediating guanosine effects. We investigated the neuroprotective effects of guanosine in hippocampal slices from A2AR-deficient mice (A2AR-/-) subjected to oxygen/glucose deprivation (OGD). Next, we assessed guanosine binding at ARs taking advantage of a fluorescent-selective A2AR antagonist (MRS7396) which could engage in a bioluminescence resonance energy transfer (BRET) process with NanoLuc-tagged A2AR. Next, we evaluated functional AR activation by determining cAMP and calcium accumulation. Finally, we assessed the impact of A1R and A2AR co-expression in guanosine-mediated impedance responses in living cells. Guanosine prevented the reduction of cellular viability and increased reactive oxygen species generation induced by OGD in hippocampal slices from wild-type, but not from A2AR-/- mice. Notably, while guanosine was not able to modify MRS7396 binding to A2AR-expressing cells, a partial blockade was observed in cells co-expressing A1R and A2AR. The relevance of the A1R and A2AR interaction in guanosine effects was further substantiated by means of functional assays (i.e., cAMP and calcium determinations), since guanosine only blocked A2AR agonist-mediated effects in doubly expressing A1R and A2AR cells. Interestingly, while guanosine did not affect A1R/A2AR heteromer formation, it reduced A2AR agonist-mediated cell impedance responses. Our results indicate that guanosine-induced effects may require both A1R and A2AR co-expression, thus identifying a molecular substrate that may allow fine tuning of guanosine-mediated responses.

Viscoelastic properties of doxorubicin-treated HT-29 cancer cells by atomic force microscopy: the fractional Zener model as an optimal viscoelastic model for cells

The malignancy of cancer cells and their response to drug treatments have been traditionally studied using solely their elastic properties. However, the study of the combined viscous and elastic properties provides a richer description of the mechanics of the cell, and achieves a more precise assessment of the effect exerted by anti-cancer treatments. We used an atomic force microscope to obtain the morphological, elastic and viscous properties of HT-29 colorectal cancer cells. Changes in these parameters were observed during exposure of the cells to doxorubicin at different times. The elastic properties were analyzed using the Hertz and Sneddon models. Furthermore, we analyzed the data to study the viscoelasticity of the cells comparing the models known as the standard linear solid, fractional Zener, generalized Maxwell, and power law. A discussion about the optimal model based in the accuracy and physical assumptions for this particular system is included. From the morphological data and viscoelasticity of HT-29 cells exposed to doxorubicin, we found that some parameters were affected differently at shorter or longer exposure times. For instance, the relaxation time suggests a measure of the cell to self-heal and it was observed to increase at shorter exposure times and then to reduce for longer exposure times to the drug. The fractional Zener model better described the mechanical properties of the cell due to the reduced number of parameters and the quality of the fit to experimental data.

Antitumor activity of a hydrogel loaded with lipophilic bismuth nanoparticles on cervical, prostate, and colon human cancer cells

The objective of this study was to analyze the antitumor activity of a hydrogel loaded with lipophilic bismuth nanoparticles on human cervical, prostate, and colon cancer cell lines. The effect of lipophilic bismuth nanoparticles on the viability of cancer cell lines (HeLa, DU145, and HCT-116) and non-cancer lung fibroblasts (HLF; LL 47[MaDo]) was determined with the MTT cell viability assay and compared with known antineoplastic drugs. The biocompatibility at an organismal level was verified in a murine model by histological examination. A lipophilic bismuth nanoparticle hydrogel at 50 µM time-dependently inhibited the growth of the three cancer cell lines, in a time-dependent way. A 1-hour exposure to 250 µM lipophilic bismuth nanoparticle hydrogel, inhibited the growth of the three cancer cell lines. The in-vitro efficacy of lipophilic bismuth nanoparticle was similar to the one of docetaxel and cisplatin, but without inhibiting the growth of non-cancer control cells. Histology confirmed the biocompatibility of lipophilic bismuth nanoparticles as there were no signs of cytotoxicity or tissue damage in any of the evaluated organs (kidney, liver, brain, cerebellum, heart, and jejunum). In conclusion, a lipophilic bismuth nanoparticle hydrogel is an innovative, low-cost alternative for the topical treatment of cervicouterine, prostate, and colon human cancers.

Slow freezing versus vitrification for the cryopreservation of zebrafish (Danio rerio) ovarian tissue

The aim of the present study was to compare the efficiency of vitrification and slow freezing techniques for the cryopreservation of zebrafish ovarian tissue containing immature follicles. In Experiment 1, assessment of cell membrane integrity by trypan blue exclusion staining was used to select the best cryoprotectant solution for each cryopreservation method. Primary growth (PG) oocytes showed the best percentage of membrane integrity (63.5 ± 2.99%) when SF4 solution (2 M methanol + 0.1 M trehalose + 10% egg yolk solution) was employed. The vitrification solution, which presented the highest membrane integrity (V2; 1.5 M methanol + 5.5 M Me₂SO + 0.5 M sucrose + 10% egg yolk solution) was selected for Experiment 2. Experiment 2 aimed to compare the vitrification and slow freezing techniques in the following parameters: morphology, oxidative stress, mitochondrial activity, and DNA damage. Frozen ovarian tissue showed higher ROS levels and lower mitochondrial activity than vitrified ovarian tissue. Ultrastructural observations of frozen PG oocytes showed rupture of the plasma membrane, loss of intracellular contents and a large number of damaged mitochondria, while vitrified PG oocytes had intact mitochondria and cell plasma membranes. We conclude that vitrification may be more effective than slow freezing for the cryopreservation of zebrafish ovarian tissue.

Determination of ADC Cytotoxicity in Immortalized Human Cell Lines

Cytotoxicity assays are a necessary first step to triage ADC molecules before moving them forward to relatively time-consuming and expensive in vivo studies. When cells are exposed to ADC molecules, antigen expressing cells can effectively take up those molecules and eventually die as a result of the released payload. This cytotoxic property of ADCs can be evaluated by measuring the percentage of living cells at the end of the incubation period. Tetrazolium colorimetric assay (MTT) is a widely used method that can be used to measure cell viability. Here we describe how to use an MTT assay to measure the cytotoxic effect of ADCs and calculate the corresponding IC₅₀. Besides the cytotoxic behavior on antigen expressing cells, ADCs can also demonstrate bystander killing of antigen negative cells in the vicinity of antigen expressing cells. Here, we report how to use a co-culture experiment to evaluate the bystander effect of ADC with the help of fluorescent protein transfected antigen negative cells.

Structure-based inhibitors of amyloid beta core suggest a common interface with tau

Alzheimer’s disease (AD) pathology is characterized by plaques of amyloid beta (Aβ) and neurofibrillary tangles of tau. Aβ aggregation is thought to occur at early stages of the disease, and ultimately gives way to the formation of tau tangles which track with cognitive decline in humans. Here, we report the crystal structure of an Aβ core segment determined by MicroED and in it, note characteristics of both fibrillar and oligomeric structure. Using this structure, we designed peptide-based inhibitors that reduce Aβ aggregation and toxicity of already-aggregated species. Unexpectedly, we also found that these inhibitors reduce the efficiency of Aβ-mediated tau aggregation, and moreover reduce aggregation and self-seeding of tau fibrils. The ability of these inhibitors to interfere with both Aβ and tau seeds suggests these fibrils share a common epitope, and supports the hypothesis that cross-seeding is one mechanism by which amyloid is linked to tau aggregation and could promote cognitive decline.

Effect of growth media on the MTT colorimetric assay in bacteria

Reduction of tetrazolium salts to colored formazan products by metabolically active cells is widely used for assessment of cell viability. Among the tetrazolium compounds most commonly used is MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide]. Numerous studies about sites and mechanisms of cellular reduction of MTT, performed in mammalian cell cultures, have identified various parameters that affect formazan production and can lead to overestimation/underestimation of viable cells or effects of treatment. Irrespective of lack of such data for prokaryotic cells, the MTT assay is commonly used for microbiological studies, which often leads to contradictory results or misinterpretation of data. The aim of this study was to investigate how components of growth media and conditions of growth, affect formazan formation by microbial cells. Results showed that MTT reduction depended on the amino acid composition of the medium. Several amino acids potentiated formazan production by Gram-positive and Gram-negative bacteria, with histidine having the strongest effect. Results of this study demonstrate that data obtained with the MTT test should be interpreted with caution, particularly when different growth media are used or treatments affect metabolic pathways, and that evaluation of the reliability of the MTT assay under specific conditions should be performed, to avoid erroneous results. Performing the assay with cells suspend in glucose-supplemented buffer would eliminate the effects of metabolites and will limit cell division during incubation with MTT. Another critical element to be considered is the choice of a proper solvent for dissolution of formazan crystals.

Synthesis and antitumor activity of fluorouracil - oleanolic acid/ursolic acid/glycyrrhetinic acid conjugates

Due to the obvious adverse effects of 5-fluorouracil that limit its clinical usefulness and considering the diverse biological activities of pentacyclic triterpenes, twelve pentacyclic triterpene-5-fluorouracil conjugates were synthesized and their antitumor activities were evaluated. The results indicated that all the single substitution targeted hybrids (7a-12a) possessed much better antiproliferative activities than the double substitution targeted hybrids (7b-12b). Hybrid 12a exhibited good antiproliferative activities against all the tested MDR cell lines. Furthermore, it was revealed that 12a could induce intracellular calcium influx, the generation of ROS, arrest the cell proliferation at the G1 phase, and activate the apoptotic signaling caspase-8, which eventually activates the apoptotic effector caspase-3 and causes the later nuclear apoptosis.

The Impact of Nylon-3 Copolymer Composition on the Efficiency of siRNA Delivery to Glioblastoma Cells

Glioblastoma multiforme is a devastating disease that has attracted enormous attention due to poor prognosis and high recurrence. Small interfering RNA (siRNA) in principle offers a promising therapeutic approach by the downregulation of disease-related genes via RNA interference. For efficient siRNA delivery to target sites, cationic polymers are often used in preclinical studies for the protection of siRNA and complex formation based on electrostatic interactions. In an effort to develop biocompatible and efficient nanocarriers with a translational outlook for optimal gene silencing at reduced toxicity, we synthesized two sets of nylon-3 copolymers with variable cationic content (DM or NM monomer) and hydrophobic subunits (CP monomer) and evaluated their suitability for in vitro siRNA delivery into glioblastoma cells. DM_0.4/CP_0.6 and NM_0.4/CP_0.6 polymers with similar subunit ratios were synthesized to compare the effect of different cationic subunits. Additionally, we utilized NM_0.2/CP_0.8 polymers to evaluate the impact of the different hydrophobic content in the polymer chain. The siRNA condensation ability and polymer–siRNA complex stability was evaluated by unmodified and modified SYBR gold assays, respectively. Further physicochemical characteristics, e.g., particle size and surface charge, were evaluated by dynamic light scattering and laser Doppler anemometry, whereas a relatively new method for polyplex size distribution analysis—tunable resistive pulse sensing—was additionally developed and compared to DLS measurements. Transfection efficiencies, the route of cell internalization, and protein knockdown abilities in glioblastoma cells were investigated by flow cytometry. Furthermore, cellular tolerability was evaluated by MTT and LDH assays. All the polymers efficiently condensed siRNA at N/P ratios of three, whereas polymers with NM cationic subunits demonstrated smaller particle size and lower polyplex stability. Furthermore, NM_0.2/CP_0.8 polyplexes with the highest hydrophobic content displayed significantly higher cellular internalization in comparison to more cationic formulations and successful knockdown capabilities. Detailed investigations of the cellular uptake route demonstrated that these polyplexes mainly follow clathrin-mediated endocytotic uptake mechanisms, implying high interaction capacity with cellular membranes. Taken together with conducive toxicity profiles, highly hydrophobic nylon-3 polymers provide an appropriate siRNA delivery agent for the potential treatment of glioblastoma.

Proflavine/acriflavine derivatives with versatile biological activities

Proflavine derivatives are extremely interesting chemotherapeutic agents, which have shown promising pharmaceutical potential due to their wide range of biological activities. This review summarizes the current state of research into the anticancer, antimicrobial, antimalarial and antileishmanial properties of these attractive compounds. Our attention has focused on new classes of proflavine conjugates, which display significant levels of anticancer activity. Highly promising cytotoxic properties have been identified in proflavine conjugates with imidazolidinones, ureas and thioureas. In particular, proflavine-dialkyldithioureas displayed substantial cytotoxic effect against the human leukemia HL-60 cells with IC₅₀ values from 7.2 to 34.0 μm. As well, palladium complexes with proflavine ligand have important biologic activity. The LC₅₀ values of these complexes were significantly lower than that of cisplatin against the SK-BR-3 cell line.

Manipulating Active Structure and Function of Cationic Antimicrobial Peptide CM15 with the Polysulfonated Drug Suramin: A Step Closer to in Vivo Complexity

Antimicrobial peptides (AMPs) kill bacteria by targeting their membranes through various mechanisms involving peptide assembly, often coupled with disorder-to-order structural transition. However, for several AMPs, similar conformational changes in cases in which small organic compounds of both endogenous and exogenous origin have induced folded peptide conformations have recently been reported. Thus, the function of AMPs and of natural host defence peptides can be significantly affected by the local complex molecular environment in vivo; nonetheless, this area is hardly explored. To address the relevance of such interactions with regard to structure and function, we have tested the effects of the therapeutic drug suramin on the membrane activity and antibacterial efficiency of CM15, a potent hybrid AMP. The results provided insight into a dynamic system in which peptide interaction with lipid bilayers is interfered with by the competitive binding of CM15 to suramin, resulting in an equilibrium dependent on peptide-to-drug ratio and vesicle surface charge. In vitro bacterial tests showed that when CM15⋅suramin complex formation dominates over membrane binding, antimicrobial activity is abolished. On the basis of this case study, it is proposed that small-molecule secondary structure regulators can modify AMP function and that this should be considered and could potentially be exploited in future development of AMP-based antimicrobial agents.

Quantifying Batrachochytrium dendrobatidis and Batrachochytrium salamandrivorans Viability

The disease chytridiomycosis is responsible for global amphibian declines. Chytridiomycosis is caused by Batrachochytrium dendrobatidis (Bd) and B. salamandrivorans (Bsal), fungal pathogens with stationary and transmissible life stages. Establishing methods that quantify growth and survival of both life stages can facilitate research on the pathophysiology and disease ecology of these pathogens. We tested the efficacy of the MTT assay, a colorimetric test of cell viability, and found it to be a reliable method for quantifying the viability of Bd and Bsal stationary life stages. This method can provide insights into these pathogens' growth and reproduction to improve our understanding of chytridiomycosis.

β-lactoglobulin-irinotecan inclusion complex as a new targeted nanocarrier for colorectal cancer cells

Beta-lactoglobulin (β-LG) is a lipocalin family member whose general function appears to be solubilizing and transport of hydrophobic molecules. Some properties such as avalability, ease of purification, and peculiar resistance to acidic environments can make β-LG as a carrier for hydrophobic and acid labile drugs for oral administration. In this protein vehicle, drug could be protected in acidic environment of stomach and then released within the basic small intestine. In this study, the potential of β-LG as a nanocarrier for oral delivery of a potent agent in colorectal cancer treatment, irinotecan, was evaluated. The nanoparticle was prepared by the physical inclusion complex method. Size, drug loading, encapsulation efficiency, and in vitro drug release at various pH values were investigated. The optimum formulation showed a narrow size distribution with an average diameter of 139.86 ± 13.75 nm and drug loading about 84.33 ± 5.03%. Based on the results obtained from docking simulation of irinotecan-complex, there are two distinct binding sites in this nanocarrier. Cytotoxicity of this nanocarrier on the HT-29 cancer cell line and AGS was measured by MTT assay. The cytotoxicity experiment showed that the drug-loaded nanocarrier was more effective than free drug. The higher release percent of drug from the β-LG complex at pH 7.4 compared to pH 1.2 indicated that the proposed nanocarrier could be introduced as a suitable nanovehicle for labile drugs in acidic medium targeted for colorectal segment.

The role of preservation in the variability of regenerative medicine products

Regenerative medicine (RM) has the potential to restore or establish normal function of cells, tissues and organs that have been lost due to age, disease or injury. It is common for the site of raw material collection, site of manufacture and site of clinical use to be different for RM products, and at the same time cells must remain viable and functional during transportation among different sites. Freezing products down to cryogenic temperatures along with cold chain transportation has become an effective method of preserving RM products. The quality of RM products along this supply chain represents the cumulative effects of all of the processing steps and all of the reagents used in the process. A variety of sources of variability in the preservation of RM products can result in both cell losses and greater variability in the quality of RM products. The purpose of this article is to review the sources of variability in the preservation process as well as the methods by which variability can be controlled or avoided.

Antimicrobial potential of bismuth lipophilic nanoparticles embedded into chitosan-based membrane

The objective of this work was to analyze the antimicrobial and antibiofilm activities of bismuth lipophilic nanoparticles (BisBAL NPs) incorporated into chitosan-based membranes. Chitosan-based membranes were homogeneously embedded with BisBAL NPs, confirming the bismuth presence by scanning electron microscopy. The tensile strength of chitosan-based membrane alone or with BisBAL NPs showed similar results as elongation, suggesting that BisBAL NP addition did not affect membrane mechanical properties. Chitosan-based membranes complemented with 100 µM of BisBAL NPs caused a complete inhibition of biofilm formation and a 90-98% growth inhibition of six different oral pathogens. Cytotoxicity studies revealed that 80% of human gingival fibroblasts were viable after a 24-h exposure to the chitosan-based membrane with 100 µM of BisBAL NPs and collagen. Altogether, we conclude that the biological properties of chitosan-based membranes supplemented with BisBAL NPs could be a very interesting option for tissue regeneration.

Site-specific glycation of Aβ1-42 affects fibril formation and is neurotoxic

Aβ1-42 is involved in Alzheimer's disease (AD) pathogenesis and is prone to glycation, an irreversible process where proteins accumulate advanced glycated end products (AGEs). N ^ϵ-(Carboxyethyl)lysine (CEL) is a common AGE associated with AD patients and occurs at either Lys-16 or Lys-28 of Aβ1-42. Methyglyoxal is commonly used for the unspecific glycation of Aβ1-42, which results in a complex mixture of AGE-modified peptides and makes interpretation of a causative AGE at a specific amino acid residue difficult. We address this issue by chemically synthesizing defined CEL modifications on Aβ1-42 at Lys-16 (Aβ-CEL16), Lys-28 (Aβ-CEL28), and Lys-16 and -28 (Aβ-CEL16&28). We demonstrated that double-CEL glycations at Lys-16 and Lys-28 of Aβ1-42 had the most profound impact on the ability to form amyloid fibrils. In silico predictions indicated that Aβ-CEL16&28 had a substantial decrease in free energy change, which contributes to fibril destabilization, and a increased aggregation rate. Single-CEL glycations at Lys-28 of Aβ1-42 had the least impact on fibril formation, whereas CEL glycations at Lys-16 of Aβ1-42 delayed fibril formation. We also tested these peptides for neuronal toxicity and mitochondrial function on a retinoic acid-differentiated SH-SY5Y human neuroblastoma cell line (RA-differentiated SH-SY5Y). Only Aβ-CEL16 and Aβ-CEL28 were neurotoxic, possibly through a nonmitochondrial pathway, whereas Aβ-CEL16&28 showed no neurotoxicity. Interestingly, Aβ-CEL16&28 had depolarized the mitochondrial membrane potential, whereas Aβ-CEL16 had increased mitochondrial respiration at complex II. These results may indicate mitophagy or an alternate route of metabolism, respectively. Therefore, our results provides insight into potential therapeutic approaches against neurotoxic CEL-glycated Aβ1-42.

Comparative detection method of early onset cytokine-induced stress in β-cells (INS-1E)

β-Cells contain a prominent endoplasmic reticulum (ER), disrupting ER homeostasis and function, activating the unfolded protein response (UPR). Currently, no direct protocols measure the UPR initiation. Current methods to measure ER stress include the quantification of nitric oxide (NO) (indirect method), Western blotting, and qRT-PCR of downstream components. However, these methods do not account for the overlap with mitochondrial dysfunction. In this study, INS-1E cells were exposed to proinflammatory cytokines to induce ER stress, as determined using NO, thioflavin T (ThT) binding, and β-cell functionality (insulin production). ER stress was confirmed through the upregulation of CHOP. Cell viability was monitored using MTT, sulforhodamine B, and the xCELLigence system. Morphological changes were monitored using electron microscopy. IL-1β exposure-induced β-cell stress after 4 H, decreased insulin levels, and increased thioflavin binding were noted. Increased NO production was only detected after 10 H, highlighting its lack of sensitivity, and the need for a continuous, selective, rapid, convenient, and economical detection method for early onset of ER stress. Standard methods (MTT and NO) failed to detect early ER stress. The xCELLigence coupled with a functional assay such as the detection of insulin levels or ThT are better predictors of ER stress in INS-1E cells.

Aspirin Inhibits Natural Killer/T-Cell Lymphoma by Modulation of VEGF Expression and Mitochondrial Function

Extranodal nasal-type natural killer/T-cell lymphoma (NKTCL) is an Epstein-Barr virus (EBV)-associated lymphoma with a strong tendency relapse or be refractory in response to chemotherapy. Development of a new strategy for NKTCL treatment is still quite necessary. In this study, we found that aspirin treatment suppresses VEGF expression in NKTCL SNK-6 cells. Further investigation showed that aspirin treatment increases histone methylation in the range of −100~0 that is proximal to the transcription start site on the VEGF promoter, subsequently decreasing the binding ability of Sp1 to the VEGF promoter with VEGF suppression. Furthermore, aspirin treatment modulates mitochondrial function with increased ROS formation and apoptosis in NKTCL cells. Aspirin treatment alone slightly inhibits NKTCL SNK-6 tumor growth and EBV replication; while in the presence of histone deacetylase inhibitor (HDACi) chidamide (CDM), aspirin significantly suppresses the VEGF signaling pathway with increased ROS overgeneration and EBV inhibition. We also showed that with the addition of chidamide, aspirin significantly suppresses NKTCL tumor growth in both in vitro cell culture and in vivo mouse model with prolonged mouse survival. This is the first time that the potential mechanism for aspirin-mediated VEGF suppression and anti-tumor effect has been discovered, and this study provides a new strategy for anti-tumor drug development for NKTCL treatment based on aspirin-mediated targeting of the VEGF signaling pathway and ROS formation.

Temperature-Gating Titania Nanotubes Regulate Migration of Endothelial Cells

External stimuli-responsive biomaterials represent a type of promising candidates for addressing the complexity of biological systems. In this study, a platform based on the combination of temperature-sensitive polymers and a nanotube array was developed for loading sphingosine 1-phosphate (S1P) and regulating the migration of endothelial cells (ECs) at desired conditions. The localized release dosage of effectors could be controlled by the change of environmental temperature. At a culture temperature above the lower critical solution temperature, the polymer "gatekeeper" with a collapsed conformation allowed the release of S1P, which in turn enhanced the migration of ECs. The migration rate of single cells was significantly enhanced up to 58.5%, and the collective migration distance was also promoted to 25.1% at 24 h and 33.2% at 48 h. The cell morphology, focal adhesion, organization of cytoskeleton, and expression of genes and proteins related to migration were studied to unveil the intrinsic mechanisms. The cell mobility was regulated by the released S1P, which would bind with the S1PR1 receptor on the cell membrane and trigger the Rho GTPase pathway.

Caffeine Neuroprotection Decreases A2A Adenosine Receptor Content in Aged Mice

Caffeine is a bioactive compound worldwide consumed with effect into the brain. Part of its action in reducing incidence or delaying Alzheimer's and Parkinson's diseases symptoms in human is credited to the adenosine receptors properties. However, the impact of caffeine consumption during aging on survival of brain cells remains debatable. This work, we investigated the effect of low-dose of caffeine on the ectonucleotidase activities, adenosine receptors content, and paying particular attention to its pro-survival effect during aging. Male young adult and aged Swiss mice drank water or caffeine (0.3 g/L) ad libitum for 4 weeks. The results showed that long-term caffeine treatment did not unchanged ATP, ADP or AMP hydrolysis in hippocampus when compared to the mice drank water. Nevertheless, the ATP/ADP hydrolysis ratio was higher in young adult (3:1) compared to the aged (1:1) animals regardless of treatment. The content of A1 receptors did not change in any groups of mice, but the content of A2A receptors was reduced in hippocampus of mice that consumed caffeine. Moreover, the cell viability results indicated that aged mice not only had increased pyknotic neurons in the hippocampus but also had reduced damage after caffeine treatment. Overall, these findings indicate a potential neuroprotective effect of caffeine during aging through the adenosinergic system.

DNA G-quadruplexes binding and antitumor activity of palladium aryl oxime ligand complexes encapsulated in either albumin or algal cellulose nanoparticles

The interactions between two Pd complexes, designated as [Pd₃(C,N-(C₆H₄C(Cl) = NO)-4)₆] (complex 1) and [Pd₃(C₁₂H₈C = NO)₆] (complex 2), with the human telomeric G-quadruplex DNA, 5'-G₃(T₂AG₃)₃-3' (HTG21), were monitored using spectroscopic, biological, and molecular modeling studies. According to the UV-vis results, these complexes can strongly induce and stabilize G-quadruplex DNA structure with K_b1 = 4.5(±0.3) × 10⁶ M^-1 and K_b2 = 1.0(±0.2) × 10⁷ M^-1via groove mode in comparison with duplex DNA. The release mechanism of the Pd complexes from BSA nanoparticles followed a biphasic pattern unlike that of algal cellulose nanoparticles in vitro. In addition, the cytotoxicity of these complexes on MCF-7 cancer cells and PBMC normal cells was evaluated and compared with cisplatin under similar experimental conditions. Furthermore, to determine and verify the interaction mode of these compounds with G-quadruplex, the molecular docking technique was also performed. Our data clearly demonstrated that complex 2 had higher activity and cytotoxicity than that of complex 1 and could be further investigated in the future as a drug discovery platform.

Guanosine Protects Striatal Slices Against 6-OHDA-Induced Oxidative Damage, Mitochondrial Dysfunction, and ATP Depletion

Parkinson's disease (PD) is a progressive neurodegenerative disorder characterized by loss of dopaminergic neurons in substantia nigra pars compacta which induces severe motor symptoms. 6-OHDA is a neurotoxin widely used in PD animal models due to its high affinity by dopamine transporter, its rapid non-enzymatic auto-oxidation which generates reactive oxygen species (ROS), oxidative stress, and for induced mitochondrial dysfunction. We previously reported an in vitro protocol of 6-OHDA-induced toxicity in brain regions slices, as a simple and sensitive assay to screen for protective compounds related to PD. Guanosine (GUO), a guanine-based purine nucleoside, is a neuroprotective molecule that is showing promising effects as an antiparkinsonian agent. To investigate the mechanisms involved on GUO-induced neuroprotection, slices of cortex, striatum, and hippocampus were incubated with GUO in the presence of 6-OHDA (100 μM). 6-OHDA promoted a decrease in cellular viability and increased ROS generation in all brain regions. Disruption of mitochondrial potential, depletion in intracellular ATP levels, and increase in cell membrane permeabilization were evidenced in striatal slices. GUO prevented the increase in ROS generation, disruption in mitochondrial potential, and depletion of intracellular ATP induced by 6-OHDA in striatal slices. In conclusion, GUO was effective to prevent oxidative events before cell damage, such as mitochondrial disruption, intracellular ATP levels depletion, and ROS generation in striatal slices subjected to in vitro 6-OHDA-induced toxicity.

Impact of PYROXD1 deficiency on cellular respiration and correlations with genetic analyses of limb-girdle muscular dystrophy in Saudi Arabia and Sudan

Next-generation sequencing is commonly used to screen for pathogenic mutations in families with Mendelian disorders, but due to the pace of discoveries, gaps have widened for some diseases between genetic and pathophysiological knowledge. We recruited and analyzed 16 families with limb-girdle muscular dystrophy (LGMD) of Arab descent from Saudi Arabia and Sudan who did not have confirmed genetic diagnoses. The analysis included both traditional and next-generation sequencing approaches. Cellular and metabolic studies were performed on Pyroxd1 siRNA C2C12 myoblasts and controls. Pathogenic mutations were identified in eight of the 16 families. One Sudanese family of Arab descent residing in Saudi Arabia harbored a homozygous c.464A>G, p.Asn155Ser mutation in PYROXD1, a gene recently reported in association with myofibrillar myopathy and whose protein product reduces thiol residues. Pyroxd1 deficiency in murine C2C12 myoblasts yielded evidence for impairments of cellular proliferation, migration, and differentiation, while CG10721 (Pyroxd1 fly homolog) knockdown in Drosophila yielded a lethal phenotype. Further investigations indicated that Pyroxd1 does not localize to mitochondria, yet Pyroxd1 deficiency is associated with decreased cellular respiration. This study identified pathogenic mutations in half of the LGMD families from the cohort, including one in PYROXD1. Developmental impairments were demonstrated in vitro for Pyroxd1 deficiency and in vivo for CG10721 deficiency, with reduced metabolic activity in vitro for Pyroxd1 deficiency.

Activity of Thioallyl Compounds From Garlic Against Giardia duodenalis Trophozoites and in Experimental Giardiasis

Fresh aqueous extracts (AGEs) and several thioallyl compounds (TACs) from garlic have an important antimicrobial activity that likely involves their interaction with exposed thiol groups at single aminoacids or target proteins. Since these groups are present in Giardia duodenalis trophozoites, in this work we evaluated the anti-giardial activity of AGE and several garlic's TACs. In vitro susceptibility assays showed that AGE affected trophozoite viability initially by a mechanism impairing cell integrity and oxidoreductase activities while diesterase activities were abrogated at higher AGE concentrations. The giardicidal activities of seven TACs were related to the molecular descriptor HOMO (Highest Occupied Molecular Orbital) energy and with their capacity to modify the -SH groups exposed in giardial proteins. Interestingly, the activity of several cysteine proteases in trophozoite lysates was inhibited by representative TACs as well as the cytopathic effect of the virulence factor giardipain-1. Of these, allicin showed the highest anti-giardial activity, the lower HOMO value, the highest thiol-modifying activity and the greatest inhibition of cysteine proteases. Allicin had a cytolytic mechanism in trophozoites with subsequent impairment of diesterase and oxidoreductase activities in a similar way to AGE. In addition, by electron microscopy a marked destruction of plasma membrane and endomembranes was observed in allicin-treated trophozoites while cytoskeletal elements were not affected. In further flow cytometry analyses pro-apoptotic effects of allicin concomitant to partial cell cycle arrest at G2 phase with the absence of oxidative stress were observed. In experimental infections of gerbils, the intragastric administration of AGE or allicin decreased parasite numbers and eliminated trophozoites in experimentally infected animals, respectively. These data suggest a potential use of TACs from garlic against G. duodenalis and in the treatment of giardiasis along with their additional benefits in the host's health.

In vitro evaluation of the antitumor effect of bismuth lipophilic nanoparticles (BisBAL NPs) on breast cancer cells

Aim

The objective of this study was to evaluate the antitumor activity of lipophilic bismuth nanoparticles (BisBAL NPs) on breast cancer cells.

Materials and methods

The effect of varying concentrations of BisBAL NPs was evaluated on human MCF-7 breast cancer cells and on MCF-10A fibrocystic mammary epitheliocytes as noncancer control cells. Cell viability was evaluated with the MTT assay, plasma membrane integrity was analyzed with the calcein AM assay, genotoxicity with the comet assay, and apoptosis with the Annexin V/7-AAD assay.

Results

BisBAL NPs were spherical in shape (average diameter, 28 nm) and agglomerated into dense electronic clusters. BisBAL NP induced a dose-dependent growth inhibition. Most importantly, growth inhibition was higher for MCF-7 cells than for MCF-10A cells. At 1 µM BisBAL NP, MCF-7 growth inhibition was 51%, while it was 11% for MCF-10A; at 25 µM BisBAL NP, the growth inhibition was 81% for MCF-7 and 24% for MCF-10A. With respect to mechanisms of action, a 24-hour exposure of 10 and 100 µM BisBAL NP caused loss of cell membrane integrity and fragmentation of tumor cell DNA. BisBAL NPs at 10 µM were genotoxic to and caused apoptosis of breast cancer cells.

Conclusion

BisBAL NP-induced growth inhibition is dose dependent, and breast cancer cells are more vulnerable than noncancer breast cells. The mechanism of action of BisBAL NPs may include loss of plasma membrane integrity and a genotoxic effect on the genomic DNA of breast cancer cells.

Malaria pigment accelerates MTT - formazan exocytosis in human endothelial cells

Haemozoin is a by-product of haemoglobin digestion by intraerythrocytic malaria parasites, which induces immunologic responses on different tissues, including endothelial cells. In the present paper, the incubation of human microvascular endothelial cells with haemozoin significantly inhibited MTT reduction, a measure of cytotoxicity, without increasing the release of cytoplasmic lactate dehydrogenase. Moreover, haemozoin did not induce apoptosis or cell cycle arrest nor decreased the number of live cells, suggesting that cells viability itself was not affected and that the inhibition of MTT reduction was only apparent and probably due to accelerated MTT-formazan exocytosis. After 30 min of MTT addition, a significant increase in the % of cells exocytosing MTT formazan crystals was observed in haemozoin-treated cells compared with control cells. Such an effect was partially reversed by the addition of genistein, an inhibitor of MTT-formazan exocytosis. The rapid release of CXCL-8, a preformed chemokine contained in Weibel-Palade bodies, confirmed that haemozoin induces a perturbation of the intracellular endothelial trafficking, including the exocytosis of MTT-formazan containing vesicles. The haem moiety of haemozoin is responsible for the observed effect. Moreover, this work underlines that MTT assay should not be used to measure cytotoxicity induced by haemozoin and other methods should be preferred.

DOX-Vit D, a Novel Doxorubicin Delivery Approach, Inhibits Human Osteosarcoma Cell Proliferation by Inducing Apoptosis While Inhibiting Akt and mTOR Signaling Pathways

Doxorubicin (DOX) is a very potent and effective anticancer agent. However, the effectiveness of DOX in osteosarcoma is usually limited by the acquired drug resistance. Recently, Vitamin D (Vit-D) was shown to suppress the growth of many human cancer cells. Taken together, we synthesized DOX-Vit D by conjugating Vit-D to DOX in order to increase the delivery of DOX into cancer cells and mitigate the chemoresistance associated with DOX. For this purpose, MG63 cells were treated with 10 µM DOX or DOX-Vit D for 24 h. Thereafter, MTT, real-time PCR and western blot analysis were used to determine cell proliferation, genes and proteins expression, respectively. Our results showed that DOX-Vit D, but not DOX, significantly elicited an apoptotic signal in MG63 cells as evidenced by induction of death receptor, Caspase-3 and BCLxs genes. Mechanistically, the DOX-Vit D-induced apoptogens were credited to the activation of p-JNK and p-p38 signaling pathway and the inhibition of proliferative proteins, p-Akt and p-mTOR. Our findings propose that DOX-Vit D suppressed the growth of MG63 cells by inducing apoptosis while inhibiting cell survival and proliferative signaling pathways. DOX-Vit D may serve as a novel drug delivery approach to potentiate the delivery of DOX into cancer cells.

Layer-by-layer DNA films incorporating highly transfecting bioreducible poly(amido amine) and polyethylenimine for sequential gene delivery

Background

The layer-by-layer (LbL) assembly method offers a molecular level control of the amount and spatial distribution of bioactive molecules. However, successful clinical translation of LbL film technology will most certainly require a better understanding and control of not only the film assembly process, but also film disassembly kinetics in physiologic conditions.

Purpose

This work focuses on the understanding and control of degradation properties of LbL films for localized gene delivery.

Methods

Bioreducible poly(amido amine)s (PAAs) containing cystaminebisacrylamide (CBA), methylenebisacrylamide, and 5-amino-1-pentanol (APOL) were synthesized by Michael addition polymerization for the construction of bioreducible LbL films capable of sequential gene delivery.

Results

The synthesized PAAs were screened for desirable buffering capacity, cell transfection, and cytotoxicity characteristics together with 25 kDa branched polyethylenimine (PEI) and cross-linked 800 Da PEI. By screening the various polycations we were able to identify a copolymer of CBA and APOL for the subsequent construction of the LbL films. By incorporating a highly transfecting polycation and a nondiffusing polycation we were able to improve the overall transfection of HEK293 and MC3T3 cells from the bioreducible LbL films. We also demonstrated the dual-stage release and transfection of two different DNAs from the LbL films.

Conclusion

The results indicate that LbL films consisting of bioreducible PAAs and non-diffusing polyelectrolytes have excellent degradation properties for the development of LbL coating technology for localized gene delivery applications.

Triglyceride Form of Docosahexaenoic Acid Mediates Neuroprotection in Experimental Parkinsonism

Parkinson’s disease (PD) is a neurodegenerative disorder of unknown etiology. The main treatment of PD consists of medication with dopamine-based drugs, which palliate the symptoms but may produce adverse effects after chronic administration. Accordingly, there is a need to develop novel neuroprotective therapies. Several studies suggest that omega-3 polyunsaturated fatty acids (n-3 PUFA) might provide protection against brain damage. Here, we studied several experimental models of PD, using striatal neuronal cultures, striatal slices, and mice, to assess the neuroprotective effects of docosahexaenoic acid (DHA), the main n-3 PUFA in the brain, administered in its triglyceride form (TG-DHA). Hence, we determined the beneficial effects of TG-DHA on neural viability following 6-hydroxydopamine (6-OHDA)-induced neurotoxicity, a well-established PD model. We also implemented a novel mouse behavioral test, the beam walking test, to finely assess mouse motor skills following dopaminergic denervation. This test showed potential as a useful behavioral tool to assess novel PD treatments. Our results indicated that TG-DHA-mediated neuroprotection was independent of the net incorporation of PUFA into the striatum, thus suggesting a tight control of brain lipid homeostasis both in normal and pathological conditions.

PGC1β regulates multiple myeloma tumor growth through LDHA-mediated glycolytic metabolism

Multiple myeloma (MM) is an incurable hematologic malignancy due to inevitable relapse and chemoresistance development. Our preliminary data show that MM cells express high levels of PGC1β and LDHA. In this study, we investigated the mechanism behind PGC1β‐mediated LDHA expression and its contribution to tumorigenesis, to aid in the development of novel therapeutic approaches for MM. Real‐time PCR and western blotting were first used to evaluate gene expression of PGC1β and LDHA in different MM cells, and then, luciferase reporter assay, chromatin immunoprecipitation, LDHA deletion report vectors, and siRNA techniques were used to investigate the mechanism underlying PGC1β‐induced LDHA expression. Furthermore, knockdown cell lines and lines stably overexpressing PGC1β or LDHA lentivirus were established to evaluate in vitro glycolysis metabolism, mitochondrial function, reactive oxygen species (ROS) formation, and cell proliferation. In addition, in vivo xenograft tumor development studies were performed to investigate the effect of PGC1β or LDHA expression on tumor growth and mouse survival. We found that PGC1β and LDHA are highly expressed in different MM cells and LDHA is upregulated by PGC1β through the PGC1β/RXRβ axis acting on the LDHA promoter. Overexpression of PGC1β or LDHA significantly potentiated glycolysis metabolism with increased cell proliferation and tumor growth. On the other hand, knockdown of PGC1β or LDHA largely suppressed glycolysis metabolism with increased ROS formation and apoptosis rate, in addition to suppressing tumor growth and enhancing mouse survival. This is the first time the mechanism underlying PGC1β‐mediated LDHA expression in multiple myeloma has been identified. We conclude that PGC1β regulates multiple myeloma tumor growth through LDHA‐mediated glycolytic metabolism. Targeting the PGC1β/LDHA pathway may be a novel therapeutic strategy for multiple myeloma treatment.