Chitosan nanoparticles fabricated through host-guest interaction for enhancing the immunostimulatory effect of CpG oligodeoxynucleotide.

CpG oligodeoxynucleotides (CpG ODNs) which can induce innate immune responses and promote adaptive immune responses, are powerful tools in defeating diseases. Here, a novel chitosan nanoparticle (CS-NPs) based on host-guest interaction has been designed for encapsulation and delivery of CpG ODNs for the first time. The CS-NPs exhibited high encapsulation efficiency (98.3%) of CpG ODNs and remained stable in storage under room temperature for at least 7 days. CS-NPs can also prevent CpG ODN diffusion at pH 7. The results of confocal laser scanning microscope images and flow cytometry show that CS-NPs can also be efficiently delivered into living cells. Furthermore, CpG@CS-NPs can increase the immunostimulatory activity of CpG ODNs. Raw 264.7 cells treated with CpG@CS-NPs demonstrated upregulation of both TNF-α and IL-6 cytokines by 13% and 40%, respectively. The newly developed CpG@CS-NPs were thus identified as an efficient system to deliver CpG-ODNs to treat various diseases.

Metabolism, CB1 cannabinoid receptor binding and in vivo activity of synthetic cannabinoid 5F-AKB48: Implications for toxicity.

AKB48 and its fluorinated derivative 5F-AKB48 are synthetic cannabinoids (SCs) which have caused hospitalizations and deaths in human users. Abuse of SCs is dangerous because users may mistake them for natural cannabis, which is generally considered to be unlikely to elicit adverse effects. The present studies were designed to investigate the in vitro oxidative metabolism of 5F-AKB48 by human microsomal fractions from different organs and sexes as well as recombinant human cytochrome P450s (P450s). Mass spectrometry data tentatively provides evidence for the existence of mono-, di-, and trihydroxylated metabolites in a successive metabolism. Experiments utilizing P450s revealed that the most active enzymes (CYP2D6, CYP2J2, CYP3A4, and CYP3A5) effectively produced mono- and dihydroxylated metabolites, while CYP3A4/5 also produced significant amounts of the trihydroxylated metabolite. Moreover, although the affinity and potency of Phase I metabolite 4OH-5F-AKB48 is reduced when compared to that of the parent drug, this metabolite nevertheless retains similar high affinity for CB1 receptors, and greater efficacy for G protein activation, when compared to THC. Finally, 5F-AKB48 produced time- and dose-dependent cannabimimetic effects in mice which were more potent, but shorter acting, than those of Δ9-THC, and were attenuated by prior treatment with the CB1 antagonist rimonabant. Based on our data, we hypothesize that while many cases of toxicity result from genetic mutations, which can lead to a decrease or even absence of activity for Phase I drug-metabolizing enzymes, other P450s could potentially increase their role in the metabolism of these SCs. Because many metabolites of SCs remain biologically active, they could contribute to the deleterious effects of these substances.

Structure-Activity Relationship of Antischistosomal Ozonide Carboxylic Acids.

Semisynthetic artemisinins and other bioactive peroxides are best known for their powerful antimalarial activities, and they also show substantial activity against schistosomes-another hemoglobin-degrading pathogen. Building on this discovery, we now describe the initial structure-activity relationship (SAR) of antischistosomal ozonide carboxylic acids OZ418 (2) and OZ165 (3). Irrespective of lipophilicity, these ozonide weak acids have relatively low aqueous solubilities and high protein binding values. Ozonides with para-substituted carboxymethoxy and N-benzylglycine substituents had high antischistosomal efficacies. It was possible to increase solubility, decrease protein binding, and maintain the high antischistosomal activity in mice infected with juvenile and adult Schistosoma mansoni by incorporating a weak base functional group in these compounds. In some cases, adding polar functional groups and heteroatoms to the spiroadamantane substructure increased the solubility and metabolic stability, but in all cases decreased the antischistosomal activity.

Potential of the zebrafish model for the forensic toxicology screening of NPS: A comparative study of the effects of APINAC and methiopropamine on the behavior of zebrafish larvae and mice.

The increased diffusion of the so-called novel psychoactive substances (NPS) and their continuous change in structure andconceivably activity has led to the need of a rapid screening method to detect their biological effects as early as possible after their appearance in the market. This problem is very felt in forensic pathology and toxicology, so the preclinical study is fundamental in the approach to clinical and autopsy cases of difficult interpretation intoxication. Zebrafish is a high-throughput suitable model to rapidly hypothesize potential aversive or beneficial effects of novel molecules. In the present study, we measured and compared the behavioral responses to two novel neuroactive drugs, namely APINAC, a new cannabimimetic drug, and methiopropamine (MPA), a methamphetamine-like compound, on zebrafish larvae (ZL) and adult mice. By using an innovative statistical approach (general additive models), it was found that the spontaneous locomotor activity was impaired by the two drugs in both species: the disruption extent varied in a dose-dependent and time-dependent manner. Sensorimotor function was also altered: i) the visual object response was reduced in mice treated with APINAC, whereas it was not after exposure to MPA; ii) the visual placing responses were reduced after treatment with both NPS in mice. Furthermore, the visual motor response detected in ZL showed a reduction after treatment with APINAC during light-dark and dark-light transition. The same pattern was found in the MPA exposed groups only at the dark-light transition, while at the transition from light to dark, the individuals showed an increased response. In conclusion, the present study highlighted the impairment of spontaneous motor and sensorimotor behavior induced by MPA and APINAC administration in both species, thus confirming the usefulness of ZL as a model for a rapid behavioural-based drug screening.

Enzyme-responsive fluorescent camptothecin prodrug/polysaccharide supramolecular assembly for targeted cellular imaging and in situ controlled drug release.

A novel enzyme-responsive supramolecular polysaccharide assembly composed of disulfide linked adamantane-naphthalimide fluorescent camptothecin prodrug (AdaCPT) and ß-CD modified hyaluronic acid (HACD) was constructed, possessing low cellular cytotoxicity and exhibiting targeted cellular imaging and controlled drug release at specific sites while providing a concurrent means for the real-time tracking of drug delivery.

Inflammation and oxidative stress are key mediators in AKB48-induced neurotoxicity in vitro.

Synthetic cannabinoids were introduced into market in early 2000s; since these "legal highs" are dramatically popular among youth, it becomes a deadly problem. Synthetic cannabinoids have high affinity to cannabinoid receptors; leading to various clinical symptoms. AKB48 (Apinaca) has been classified as a third-generation synthetic cannabinoid for the first time in 2014. The toxicity profile of AKB48 is unclear due to little information that mainly obtained from clinical and forensic cases; however, it is believed to be similar with other psychoactive substances. Thus, we aimed to investigate the possible toxicity mechanisms of AKB48 in SH-SY5Y (human bone marrow neuroblastoma) cell line. IC50 value of AKB48 was calculated as 160.91 µM by MTT assay. AKB48 treatment enhanced (≥1.2-fold) the fluorescence intensity indicating increased reactive oxygen species production; however, glutathione levels did not changed in the range of 25-200 µM exposure concentrations. Cannabinoid type-1 receptor (CB1) expression was increased ≥15-fold in the range of 25-50 µM of AKB48, while cannabinoid type-2 receptor (CB2) did not expressed in SH-SY5Y cells. Interleukin-6 (IL-6) and tumor necrosis factor-α (TNF- α) were up-regulated with a dose-dependent manner, and the profiles were almost identical; however, mitogen-activated protein kinase 8 (MAPK 8) was only upregulated with 25 µM of AKB48 and nuclear factor kappa B (NF-ĸB) did not change. Our results should raise the concerns about the safety associated with synthetic cannabinoids uses.

A Novel Chemiluminescent Probe Based on 1,2-Dioxetane Scaffold for Imaging Cysteine in Living Mice.

A novel chemiluminescent probe for detection of cysteine (Cys) from other biothiols has been reported by utilizing the excellent chemiluminescent Schaap's adamantylidene-dioxetane scaffold. After careful assessment, the probe CL-Cys could detect Cys with high sensitivity and total light photons increased by 28-fold after the probe was treated with Cys, with the detection limit of 7.5 × 10-8 M. Finally, CL-Cys was further utilized for the chemiluminescent imaging of endogenous Cys in a living mouse. In general, this probe has a remarkable ability to detect Cys, which provides a valuable method for interrogation of the Cys roles in more biological and pathological processes.

Improved safety margin for embryotoxicity in rats for the new endoperoxide artefenomel (OZ439) as compared to artesunate.

BACKGROUND: Combination medicines including an artemisinin are the mainstay of antimalarial therapy. Artemisinins are potent embryotoxicants in animal species due to their trioxane moiety. METHODS: As part of its development, the new synthetic trioxolane antimalarial artefenomel (OZ439) was tested in rat whole embryo culture and in rat embryo-fetal toxicity studies with dosing throughout organogenesis or with a single dose on Gestational Day (GD) 12. The single-dose studies included groups treated with artesunate to allow a direct comparison of the embryotoxicity of the two antimalarials and included toxicokinetics hematology and histological examination of embryos. In addition, the distribution of artefenomel-related material in plasma was determined after the administration of 14 C-artefenomel. RESULTS: Artefenomel and artesunate showed similar patterns of embryotoxicity including cardiovascular defects and resorption with a steep dose-response. They both also caused a depletion of circulating embryonic erythroblasts both in vitro and in vivo and decreases in maternal reticulocyte count. However, artefenomel was ∼250-fold less potent than the active metabolite of artesunate (dihydroartemisinin) as an embryotoxicant in vitro. The safety margin (based on AUC) for artefenomel administered on GD 12 was approximately 100-fold greater than that for artesunate. Also, unlike artesunate, artefenomel was not a selective developmental toxicant. CONCLUSIONS: The lesser embryotoxicity of artefenomel is likely linked to its original design which included two blocking side groups that had been introduced to lower the reactivity with ferrous iron. Our data support the hypothesis that artefenomel's improved safety margin is linked to a lower potential for inhibiting heme biosynthesis in embryonic erythroblasts.

Dipeptidyl peptidase-4 independent cardiac dysfunction links saxagliptin to heart failure.

Saxagliptin treatment has been associated with increased rate of hospitalization for heart failure in type 2 diabetic patients, though the underlying mechanism(s) remain elusive. To address this, we assessed the effects of saxagliptin on human atrial trabeculae, guinea pig hearts and cardiomyocytes. We found that the primary target of saxagliptin, dipeptidyl peptidase-4, is absent in cardiomyocytes, yet saxagliptin internalized into cardiomyocytes and impaired cardiac contractility via inhibition of the Ca2+/calmodulin-dependent protein kinase II-phospholamban-sarcoplasmic reticulum Ca2+-ATPase 2a axis and Na+-Ca2+ exchanger function in Ca2+ extrusion. This resulted in reduced sarcoplasmic reticulum Ca2+ content, diastolic Ca2+ overload, systolic dysfunction and impaired contractile force. Furthermore, saxagliptin reduced protein kinase C-mediated delayed rectifier K+ current that prolonged action potential duration and consequently QTc interval. Importantly, saxagliptin aggravated pre-existing cardiac dysfunction induced by ischemia/reperfusion injury. In conclusion, our novel results provide mechanisms for the off-target deleterious effects of saxagliptin on cardiac function and support the outcome of SAVOR-TIMI 53 trial that linked saxagliptin with the risk of heart failure.

Involvement of insulin resistance in D-galactose-induced age-related dementia in rats: Protective role of metformin and saxagliptin.

Age-related dementia is one of the most devastating disorders affecting the elderly. Recently, emerging data suggest that impaired insulin signaling is the major contributor in the development of Alzheimer's dementia (AD), which is the most common type of senile dementia. In the present study, we investigated the potential therapeutic effects of metformin (Met) and saxagliptin (Saxa), as insulin sensitizing agents, in a rat model of brain aging and AD using D-galactose (D-gal, 150 mg/kg/day, s.c. for 90 successive days). Six groups of adult male Wistar rats were used: normal, D-gal, Met (500 mg/kg/day, p.o), and Saxa (1 mg/kg/day, p.o) control groups, as well as D-gal/Met and D-gal/Sax treated groups. Impaired learning and memory function was observed in rats treated with D-gal using Morris water maze test. Biochemical and histopathological findings also revealed some characteristic changes of AD in the brain that include the increased content of acetylcholine, glutamate, and phosphorelated tau, as well as deposition of amyloid plaques and neurofibrillary tangles. Induction of insulin resistance in experimentally aged rats was evidenced by increased blood glycated hemoglobin, brain contents of insulin and receptors for advanced glycated end-products, as well as decreased brain insulin receptor level. Elevation of oxidative stress markers and TNF-α brain content was also demonstrated. Met and Saxa, with a preference to Met, restored the normal memory and learning functions in rats, improved D-gal-induced state of insulin resistance, oxidative stress and inflammation, and ameliorated the AD biochemical and histopathological alterations in brain tissues. Our findings suggest that D-gal model of aging results in a diminishing of learning and memory function by producing a state of impaired insulin signaling that causes a cascade of deleterious events like oxidative stress, inflammation, and tau hyper-phosphorylation. Reversing of these harmful effects by the use of insulin-sensitizing drugs like Met and Saxa suggests their involvement in alleviation insulin resistance as the underlying pathology of AD and hence their potential use as anti-dementia drugs.

Potentialization of N-a-tosyl-L-phenylalanine chloromethyl ketone (TPCK) cytotoxic activity by 2-(1-adamantylamino)-6-methylpyridine (AdAMP) in human ovarian cancer cells.

OBJECTIVES: TNF is one of the key cytokines involved in cancer development. TNF signaling can result in both stimulating and inhibitory signals that can result in opposite biological effects in cancerogenesis. 2-(1-adamantylamino)-6-methylpyridine (AdAMP) enhances TNF secretion whereas N-a-tosyl-L-phenylalanine chloromethyl ketone (TPCK) is a NF-κB inhibitor potentially stimulating proapoptotic TNF signals. The aim of the study was to assess the effect of TPCK in combination with AdAMP on human ovarian cells. MATERIAL AND METHODS: CAOV-1 human ovarian cell line was incubated with TPCK and AdAMP for 24 hours. The cytotoxic effect was evaluated in a crystal violet assay. A monoclonal antibody against TNF, Infliximab, was added to examine the possible mechanism of interactions. RESULTS: Depending on concentration, AdAMP potentialized cytotoxic activity of TPCK or had a synergistic effect with TPCK. Infliximab did not reverse cytotoxicity of AdAMP and TPCK and in some cytotoxic and non-cytotoxic concentrations even enhanced their cytotoxicity. CONCLUSIONS: AdAMP and TPCK cytotoxicity seems to be dependent on TNF signaling, however, the exact mechanism of interactions remains unclear.

Pharmaco-toxicological effects of the novel third-generation fluorinate synthetic cannabinoids, 5F-ADBINACA, AB-FUBINACA, and STS-135 in mice. In vitro and in vivo studies.

INTRODUCTION: 5F-ADBINACA, AB-FUBINACA, and STS-135 are 3 novel third-generation fluorinate synthetic cannabinoids that are illegally marketed as incense, herbal preparations, or research chemicals for their psychoactive cannabis-like effects. METHODS: The present study aims at investigating the in vitro and in vivo pharmacological activity of 5F-ADBINACA, AB-FUBINACA, and STS-135 in male CD-1 mice, comparing their in vivo effects with those caused by the administration of Δ9 -THC and JWH-018. In vitro competition binding experiments revealed a nanomolar affinity and potency of the 5F-ADBINACA, AB-FUBINACA, and STS-135 on mouse and human CB1 and CB2 receptors. Moreover, these synthetic cannabinoids induced neurotoxicity in murine neuro-2a cells. RESULTS: In vivo studies showed that 5F-ADBINACA, AB-FUBINACA, and STS-135 induced hypothermia; increased pain threshold to both noxious mechanical and thermal stimuli; caused catalepsy; reduced motor activity; impaired sensorimotor responses (visual, acoustic, and tactile); caused seizures, myoclonia, and hyperreflexia; and promoted aggressiveness in mice. Behavioral and neurological effects were fully prevented by the selective CB1 receptor antagonist/inverse agonist AM 251. Differently, the visual sensory response induced by STS-135 was only partly prevented by the AM 251, suggesting a CB1 -independent mechanism. CONCLUSIONS: For the first time, the present study demonstrates the pharmaco-toxicological effects induced by the administration of 5F-ADBINACA, AB-FUBINACA, and STS-135 in mice and suggests their possible detrimental effects on human health.

Acute Toxicity of Vildagliptin.

This article describes acute toxicity data in cynomolgus monkeys following oral treatment with vildagliptin, a dipeptidyl peptidase-4 inhibitor. Acute toxicity symptoms in cynomolgus monkeys include edema formation of the extremities, tails, and face associated with skeletal muscle necrosis, and elevations of lactate dehydrogenase, creatine kinase, alanine transaminase, and aspartate aminotransferase activities in the serum; hypothermia; hypotension; tachycardia; moribundity; and death in a few isolated instances. In surviving animals, symptoms were reversible even if treatment was continued. Cynomolgus monkeys from Mauritius appear more sensitive than monkeys of Asian origin. The underlying mechanism(s) of these symptoms in cynomolgus monkeys is currently not well understood, although a vascular mechanism including initial vasoconstriction and subsequent vascular leakage in distal extremities may play a role. The monkey data are reviewed and discussed in the context of other preclinical and clinical data, and it is concluded that acute toxicity following vildagliptin treatment is a monkey-specific phenomenon without relevance for humans.

Acute myocardial infarction, associated with the use of a synthetic adamantyl-cannabinoid: a case report.

BACKGROUND: "Legal highs" are novel psychoactive substances that have evaded statutory control. Synthetic cannabinoid compounds with adamantane moieties have recently been identified, which have high potency at target receptors and are undetectable on conventional toxicology testing. However, little is known about any harmful effects, and their potential to cause serious ill health. We describe a case of myocardial infarction following the use of this class of drug. CASE PRESENTATION: We report the case of a 39-year-old man admitted after an out-of-hospital cardiac arrest, in whom ECG and elevated cardiac enzymes confirmed ST-elevation myocardial infarction. Normal coronary perfusion was restored after thrombectomy and coronary artery stenting. In the hours preceding his admission, the patient is known to have consumed the legal high product "Black Mamba". Subsequent urine testing confirmed the presence of an adamantyl-group synthetic cannabinoid, whilst cannabis, cocaine, amphetamines and other drugs of abuse were not detected. CONCLUSION: The use of legal highs is being increasingly recognised, but the chemical compositions and physiological effects of these drugs are poorly characterised and are continually changing. Synthetic cannabinoids, rarely identified on toxicological testing, can be linked to serious adverse cardiovascular events. This case highlights the importance of testing for novel psychoactive compounds, and recognising their potential to cause life-threatening conditions.

Design, Synthesis and Structure-Activity Relationship Studies of Novel 4 (1-adamantyl) Phenyl Analogues as HIF-1α Inhibitors.

Hypoxia inducible factor-1 (HIF-1) is a key mediator during cancer cells to adapt tumor hypoxic condition. In this study, a series of adamantane-based compounds were synthesized and evaluated as potential inhibitors of HIF-1α. Examination of their structure-activity relationship (SAR) identified the adamantane-containing indole derivative 20a as a potent inhibitor of HIF-1α in Hep3B cell lines under tumor hypoxia (IC50 = 0.02 µM). The study herein may provide valuable information for the development of novel therapeutics against cancer and tumor angiogenesis.

A biodegradable adamantane polymer with ketal linkages in its backbone for gene therapy.

In this report we present a polyketal, termed pADK, which has adamantane groups embedded in its backbone, and degrades into neutral excretable compounds. pADK was synthesized via click chemistry and had a MW of 49 472 and a PDI of 1.74. We demonstrate here that pADK can increase the transfection efficiency of CD1800 (PEI of 1800 modified ß-cyclodextrin) 60 fold, yet cause no increase in toxicity.

Saxagliptin affects long-bone microarchitecture and decreases the osteogenic potential of bone marrow stromal cells.

Diabetes mellitus is associated with a decrease in bone quality and an increase in fracture incidence. Additionally, treatment with anti-diabetic drugs can either adversely or positively affect bone metabolism. In this study we evaluated: the effect of a 3-week oral treatment with saxagliptin on femoral microarchitecture in young male non-type-2-diabetic Sprague Dawley rats; and the in vitro effect of saxagliptin and/or fetal bovine serum (FBS), insulin or insulin-like growth factor-1 (IGF1), on the proliferation, differentiation (Runx2 and PPAR-gamma expression, type-1 collagen production, osteocalcin expression, mineralization) and extracellular-regulated kinase (ERK) activation, in bone marrow stromal cells (MSC) obtained from control (untreated) rats and in MC3T3E1 osteoblast-like cells. In vivo, oral saxagliptin treatment induced a significant decrease in the femoral osteocytic and osteoblastic density of metaphyseal trabecular bone and in the average height of the proximal cartilage growth plate; and an increase in osteoclastic tartrate-resistant acid phosphatase (TRAP) activity of the primary spongiosa. In vitro, saxagliptin inhibited FBS-, insulin- and IGF1-induced ERK phosphorylation and cell proliferation, in both MSC and MC3T3E1 preosteoblasts. In the absence of growth factors, saxagliptin had no effect on ERK activation or cell proliferation. In both MSC and MC3T3E1 cells, saxagliptin in the presence of FBS inhibited Runx2 and osteocalcin expression, type-1 collagen production and mineralization, while increasing PPAR-gamma expression. In conclusion, orally administered saxagliptin induced alterations in long-bone microarchitecture that could be related to its in vitro down-regulation of the ERK signaling pathway for insulin and IGF1 in MSC, thus decreasing the osteogenic potential of these cells.

Benchmarking in vitro covalent binding burden as a tool to assess potential toxicity caused by nonspecific covalent binding of covalent drugs.

Despite several advantages of covalent inhibitors (such as increased biochemical efficiency, longer duration of action on the target, and lower efficacious doses) over their reversible binding counterparts, there is a reluctance to use covalent inhibitors as a drug design strategy in pharmaceutical research. This reluctance is due to their anticipated reactions with nontargeted macromolecules. We hypothesized that there may be a threshold limit for nonspecific covalent binding, below which a covalent binding drug may be less likely to cause toxicity due to irreversible binding to off-target macromolecules. Estimation of in vivo covalent binding burden from in vitro data has previously been used as an approach to distinguish those agents more likely to cause toxicity (e.g., hepatotoxicity) via metabolic activation to reactive metabolites. We have extended this approach to nine covalent binding drugs to determine in vitro covalent binding burden. In vitro covalent binding burden was determined by incubating radiolabeled drugs with pooled human hepatocytes. These data were scaled to an estimate of in vivo covalent binding burden by combining the in vitro data with daily dose. Scaled in vivo daily covalent binding burden of marketed covalent drugs was found to be under 10 mg/day, which is in agreement with previously reported threshold value for metabolically activated reversible drugs. Covalent binding was also compared to the intrinsic reactivities of the covalent inhibitors assessed using nucleophiles glutathione and N-α-acetyl lysine. The intrinsic reactivity did not correlate with observed in vitro covalent binding, which demonstrated that the intrinsic reactivity of the electrophilic groups of covalent drugs does not exclusively account for the extent of covalent binding. The ramifications of these findings for consideration of using a covalent strategy in drug design are discussed.

Development of a low toxicity, effective pDNA vector based on noncovalent assembly of bioresponsive amino-ß-cyclodextrin:adamantane-poly(vinyl alcohol)-poly(ethylene glycol) transfection complexes.

A host:guest-derived gene delivery vector has been developed, based on the self-assembly of cationic ß-CD derivatives with a poly(vinyl alcohol) (MW 27 kDa) (PVA) main chain polymer bearing poly(ethylene glycol) (MW 750) (PEG) or MW 2000 PEG and acid-labile adamantane-modified (Ad) grafts through an acid-sensitive benzylidene acetal linkage. These components were investigated for their ability to promote supramolecular complex formation with pDNA using two different assembly schemes, involving either precomplexation of the pendent Ad-PVA-PEG polymer with the cationic ß-CD derivatives before pDNA condensation (method A) or pDNA condensation with the cationic ß-CD derivatives prior to addition of Ad-PVA-PEG to engage host:guest complexation (method B). The pendent polymers were observed to degrade under acidic conditions while remaining intact for more than 5 days at pH 7. HeLa cell culture data show that these materials have 10(3)-fold lower cytotoxicities than 25 kDa bPEI while maintaining transfection efficiencies that are superior to those observed for this benchmark cationic polymer transfection reagent when the method A assembly scheme is employed. These findings suggest that degradable cationic polymer constructs employing multivalent host:guest interactions may be an effective and low-toxicity vehicle for delivering nucleic acid cargo to target cells.