Aplysin Retards Pancreatic Necrosis and Inflammatory Responses in NOD Mice by Stabilizing Intestinal Barriers and Regulating Gut Microbial Composition.

Aplysin is a brominated sesquiterpene with an isoprene skeleton and has biological activities. The purpose of this study is to investigate the inhibitory effect of aplysin on spontaneous pancreatic necrosis in nonobese diabetic (NOD) mice and its potential mechanisms. Results showed that NOD mice at 12 weeks of age showed obvious spontaneous pancreatic necrosis, damaged tight junctions of intestinal epithelia, and widened gaps in tight and adherens junctions. Aplysin intervention was able to alleviate spontaneous pancreatic necrosis in NOD mice, accompanied with decreased serum endotoxin levels and downregulated expressions of Toll-like receptor 4 and its related molecules MyD88, TRAF-6, NF-κB p65, TRIF, TRAM, and IRF-3, as well as protein levels of interleukin-1ß and interferon-ß in pancreatic tissues. In addition, we observed obvious improvements of intestinal mucosal barrier function and changes of gut microbiota in the relative abundance at the phylum level and the genus level in aplysin-treated mice compared with control mice. Together, these data suggested that aplysin could retard spontaneous pancreatic necrosis and inflammatory responses in NOD mice through the stabilization of intestinal barriers and regulation of gut microbial composition.

Antimycobacterial Activity of Laurinterol and Aplysin from Laurencia johnstonii.

Marine environments represent a great opportunity for the discovery of compounds with a wide spectrum of bioactive properties. Due to their large variety and functions derived from natural selection, marine natural products may allow the identification of novel drugs based not only on newly discovered bioactive metabolites but also on already known compounds not yet thoroughly investigated. Since drug resistance has caused an increase in infections by Mycobacterium tuberculosis and nontuberculous mycobacteria, the re-evaluation of known bioactive metabolites has been suggested as a good approach to addressing this problem. In this sense, this study presents an evaluation of the in vitro effect of laurinterol and aplysin, two brominated sesquiterpenes isolated from Laurencia johnstonii, against nine M. tuberculosis strains and six nontuberculous mycobacteria (NTM). Laurinterol exhibited good antimycobacterial activity, especially against nontuberculous mycobacteria, being remarkable its effect against Mycobacterium abscessus, with minimum inhibitory concentration (MIC) values lower than those of the reference drug imipenem. This study provides further evidence for the antimycobacterial activity of some sesquiterpenes from L. johnstonii, which can be considered interesting lead compounds for the discovery of novel molecules to treat NTM infections.

Oral administration of the casein kinase 2 inhibitor TBB leads to persistent KCa2.2 channel up-regulation in the epileptic CA1 area and cortex, but lacks anti-seizure efficacy in the pilocarpine epilepsy model.

Temporal lobe epilepsy (TLE) is the most common epileptic syndrome in adults and often presents with seizures that prove intractable with currently available anticonvulsants. Thus, there is still a need for new anti-seizure drugs in this condition. Recently, we found that the casein kinase 2 inhibitor 4,5,6,7-tetrabromotriazole (TBB) prevented the emergence of spontaneous epileptic discharges in an acute in vitro epilepsy model. This prompted us to study the anti-seizure effects of TBB in the pilocarpine model of chronic epilepsy in vivo. To this end, we performed long-term video-EEG monitoring lasting 78-167 days of nine chronically epileptic rats and obtained a baseline seizure rate of 3.3 ± 1.3 per day (baseline of 27-80 days). We found a significant age effect with more pronounced seizure rates in older animals as compared to younger ones. However, the seizure rate increased to 6.3 ± 2.2 per day during the oral TBB administration (treatment period of 21-50 days), and following discontinuation of TBB, this rate remained stable with 5.2 ± 1.4 seizures per day (follow-up of 30-55 days). After completing the video-EEG during the follow-up the hippocampal tissue was prepared and studied for the expression of the Ca2+-activated K+ channel KCa2.2. We found a significant up-regulation of KCa2.2 in the epileptic CA1 region and in the neocortex, but in no other hippocampal subfield. Hence, our findings indicate that oral administration of TBB leads to persistent up-regulation of KCa2.2 in the epileptic CA1 subfield and in the neocortex, but lacks anti-seizure efficacy in the pilocarpine epilepsy model.

Protective Effect of Aplysin Supplementation on Intestinal Permeability and Microbiota in Rats Treated with Ethanol and Iron.

Aplysin, a kind of phytochemicals or phytonutrients, is purified from red alga Laurencia tristicha. The present study aims to investigate the influence of aplysin on changes of intestinal permeability and microbiota induced by excessive ethanol and iron. Thirty male rats were randomly divided into three groups (10/group): control group (normal saline); ethanol + iron group as EI treated with ethanol (8⁻12 mL/kg/day) and iron (1000 mg/kg) in diet; EI supplemented with aplysin (150 mg/kg/day) group as AEI; the trial lasts for 12 weeks. The result showed that levels of plasma endotoxin, fatty acid-binding protein 2, D-lactic acid, diamine oxidase were increased in rats in the EI group; and significantly decreased by 14%, 17%, 26%, 16%, respectively (p < 0.05) in the AEI group after the 12-week aplysin treatment. Moreover, in the AEI group the amount of Escherichia coli and Bacteroides fragilis were higher, while the amount of Lactobacillus, Bifidobacterium and Clostridium were lower than those in the EI group. The expressions of iron transporters divalent-metal transporter 1(DMT1) and ferroportin 1(FPN1) were significantly upregulated in the EI group compared to those in the control group. In conclusion, aplysin could effectively improve intestinal permeability and intestinal flora disorder induced with excessive ethanol and iron.

Allosteric modulation of α4ß2* nicotinic acetylcholine receptors: Desformylflustrabromine potentiates antiallodynic response of nicotine in a mouse model of neuropathic pain.

BACKGROUND: Neuronal nicotinic acetylcholine receptors (nAChRs) are ligand-gated ion channels. The α4ß2 subtype of nAChRs plays an important role in the mediation of pain and several nicotine-evoked responses. Agonists and partial agonists of α4ß2 nAChRs show efficacy in animal pain models. In addition, the antinociceptive properties of nicotine, a non-selective nAChR agonist with a high affinity for α4ß2 nAChRs, is well-known. There is a growing body of evidence pointing to allosteric modulation of nAChRs as an alternative treatment strategy in experimental pain. Desformylflustrabromine (dFBr) is a positive allosteric modulator (PAM) at α4ß2 nAChRs that enhances agonist responses without activating receptors. We hypothesized that dFBr may enhance nicotine-induced antinociception. METHODS: The present study investigated whether dFBr could attenuate mouse chronic constriction injury (CCI)-induced neuropathic pain by increasing endogenous cholinergic tone or potentiating the nicotine-evoked antiallodynic response. RESULTS: We found that subcutaneous administration of dFBr failed to reduce pain behaviour on its own. However, the combination of dFBr with nicotine significantly reversed neuropathic pain behaviour dose- and time-dependently without motor impairment. Our data revealed that this effect was mediated by the α4ß2 nAChRs by using competitive α4ß2 antagonist dihydro-ß-erythroidine. In addition, dFBr failed to potentiate the antiallodynic effect of morphine, which shows the effect of dFBr is unique to α4ß2 nAChRs. CONCLUSIONS: The present results suggest that allosteric modulation of α4ß2 nAChR may provide new strategies in chronic neuropathic pain. SIGNIFICANCE: α4ß2 nAChRs are involved in pain modulation. dFBr, a PAM at α4ß2 nAChRs, potentiates the nicotine response dose-dependently in neuropathic pain. Thus, the present results suggest that allosteric modulation of α4ß2* nAChR may provide new strategies in chronic neuropathic pain.

Reversal of Nicotine Withdrawal Signs Through Positive Allosteric Modulation of α4ß2 Nicotinic Acetylcholine Receptors in Male Mice.

Introduction: Nicotine withdrawal symptoms are important factors in determining the relapse rate to tobacco smoking and drugs that diminish these symptoms would potentially have a higher success rate as smoking cessation aids. Unlike US Food and Drug administration approved smoke cessation aids (nicotine and varenicline) which act as nicotinic acetylcholine receptors (nAChRs) agonists, desformylflustrabromine (dFBr) acts as a nAChR positive allosteric modulator with higher selectivity to the α4ß2 nAChR. In animal studies, dFBr was well tolerated and reduced intravenous nicotine self-administration. In this study, we use behavioral test in mouse model of spontaneous nicotine withdrawal to assess the effect of dFBr on nicotine withdrawal symptoms. Methods: Spontaneous nicotine withdrawal in nicotine-dependent ICR male mice was established 18-24 h after termination (minipump removal) of 14 days infusion of nicotine. After that (day 15), spontaneous signs of nicotine withdrawal were examined in the following order: anxiety-like behaviors, somatic signs, and then hyperalgesia using previously published behavioral protocols. Fifteen minutes before withdrawal signs testing, mice received a subcutaneous acute injection of vehicle or dFBr at the doses of 0.02, 0.1, and 1 mg/kg to determine the effect of dFBr on nicotine withdrawal symptoms. Results: dFBr produced dose-dependent reversal of nicotine withdrawal signs in mouse model of spontaneous nicotine withdrawal. Implications: Positive allosteric modulators of nAChR such as dFBr reduce nicotine withdrawal symptoms supporting the potential clinical use of this novel class of nAChR-based therapeutics as smoking cessation aid.

In vivo treatment with the casein kinase 2 inhibitor 4,5,6,7- tetrabromotriazole augments the slow afterhyperpolarizing potential and prevents acute epileptiform activity.

OBJECTIVE: The slow afterhyperpolarizing potential (sAHP) following prolonged depolarization is a major intrinsic mechanism of neuronal inhibition, by powerfully dampening excitability for up to 2 s. Therefore, an altered sAHP function might be vulnerable to hyperexcitable states such as epilepsy. Here, we have investigated the role of casein kinase 2 (CK2) on the sAHP in control and chronically epileptic tissue. METHODS: Using the rat pilocarpine model of chronic temporal lobe epilepsy, we performed whole-cell patch-clamp recordings of acutely isolated CA1 pyramidal cells and field potential measurements on hippocampal slices. RESULTS: Chronic oral administration of the CK2 inhibitor 4,5,6,7-tetrabromotriazole (TBB) for 4 days prior to brain dissection caused a significant increase of the sAHP-mediating current in both control and epileptic tissues. In contrast, when TBB was acutely applied during the patch-clamp recording, the sAHP remained unaltered, indicating that chronic CK2 inhibition was required for sAHP augmentation. To test whether CK2 inhibition also has an anticonvulsive effect, we evoked recurrent epileptiform discharges (REDs) in hippocampal slice preparations by Mg²âº removal. It is important to note that chronic oral TBB administration abolished REDs induced by 0-Mg²âº solution, suggesting that CK2 inhibition indeed has anticonvulsive and perhaps antiepileptogenic properties. SIGNIFICANCE: Our data demonstrated that CK2 inhibition augments the sAHP and might represent a novel mechanism of action of anticonvulsant drugs.

Metabolic regulation of cancer cell side population by glucose through activation of the Akt pathway.

Side population (SP) cells within tumors are a small fraction of cancer cells with stem-like properties that can be identified by flow cytometry analysis based on their high ability to export certain compounds such as Hoechst 33342 and chemotherapeutic agents. The existence of stem-like SP cells in tumors is considered as a key factor contributing to drug resistance, and presents a major challenge in cancer treatment. Although it has been recognized for some time that tumor tissue niches may significantly affect cancer stem cells (CSCs), the role of key nutrients such as glucose in the microenvironment in affecting stem-like cancer cells and their metabolism largely remains elusive. Here we report that SP cells isolated from human cancer cells exhibit higher glycolytic activity compared to non-SP cells. Glucose in the culture environment exerts a profound effect on SP cells as evidenced by its ability to induce a significant increase in the percentage of SP cells in the overall cancer cell population, and glucose starvation causes a rapid depletion of SP cells. Mechanistically, glucose upregulates the SP fraction through ATP-mediated suppression of AMPK and activation of the Akt pathway, leading to elevated expression of the ATP-dependent efflux pump ABCG2. Importantly, inhibition of glycolysis by 3-BrOP significantly reduces SP cells in vitro and impairs their ability to form tumors in vivo. Our data suggest that glucose is an essential regulator of SP cells mediated by the Akt pathway, and targeting glycolysis may eliminate the drug-resistant SP cells with potentially significant benefits in cancer treatment.

Halogenated aromatic amino acid 3,5-dibromo-D: -tyrosine produces beneficial effects in experimental stroke and seizures.

The effects of the halogenated aromatic amino acid 3,5-dibromo-D: -tyrosine (3,5-DBr-D: -Tyr) were studied in rat models of stroke and epileptic seizures caused by middle cerebral artery occlusion (MCAo) through respective intracerebral injection of endothelin-1 (ET-1) and intraperitoneal (i.p.) injection of pentylenetetrazole (PTZ). 3,5-DBr-D: -Tyr was administered as three bolus injections (30 or 90 mg/kg, i.p.) starting at 30, 90, and 180 min after ET-1 administration or as a single bolus (30 mg/kg, i.p.) 15 min prior to PTZ administration. Neurological deficits and infarct volume were estimated 3 days after ET-1 administration and seizure score was assessed during the first 20 min after PTZ administration. The safety of 3,5-DBr-D: -Tyr was evaluated in control animals using telemetry to measure cardiovascular parameters and immunostaining to assess the level of activated caspase-3. 3,5-DBr-D: -Tyr significantly improved neurological function and reduced infarct volume in the brain even when the treatment was initiated 3 h after the onset of MCAo. 3,5-DBr-D: -Tyr significantly depressed PTZ-induced seizures. 3,5-DBr-D: -Tyr did not cause significant changes in arterial blood pressure, heart rate and spontaneous locomotor activity, nor did it increase the number of activated caspase-3 positive cells in the brain. We conclude that 3,5-DBr-D: -Tyr, by alleviating the deleterious effects of MCAo and PTZ in rats with no obvious intrinsic effects on cardiovascular parameters and neurodegeneration, exhibits promising potential as a novel therapeutic direction for stroke and seizures.

Enantioselective cytotoxic activity of bromine-substituted analogues of ifosfamide. A microsomal implication.

Nine investigated chlorobromine-, bromine-, and dibromine-ifosfamide analogues including 3 racemates and 6 enantiomers, caused about 10-fold increase in in vitro cytotoxic activity, similar to reference standards ifosfamide and cyclophosphamide in HeLa (KB) human tumor cell culture systems with the addition of rat liver microsomal preparations (ED50 = 0.11 - 0.27 x 10(-3) mole/l) as compared to microsomally non induced samples. The chlorobromine-analogues (ED50 = 0.11 - 0.20 x 10(-3) mole/l) demonstrated the highest cytotoxicity in comparison with bromine-, or dibromine-analogues (SAR). Their levorotatory (-)-(S)- enantiomers (ED50 = 0.11 : 0.21 : 0.24 x 10(-3) mole/l) appear to be more active than their dextrorotatory (+)-(R)-antipodes (ED50 = 0.20 : 0.26 : 0.27 x 10(-3) mole/l, respectively) (ESAR). The stereodifferentiated enhancement of their in vitro cytotoxicity, correlated with the decreasing of in vivo L1210 antileukemic effect following phenobarbital metabolic induction in terms of a whole--strong antitumor activity, indicate that their cytostatic activity depends enantioselectively on the mixed function oxidases-system activity, and presumably on the efficacy of the rate of drug metabolic transformation to their cytostatically active metabolites/intermediates.

[Diagnosis and therapy of bromoderma tuberosum]. / Zur Diagnostik und Therapie des Bromoderma tuberosum

After taking bromine-containing drugs two patients developed bromoderma on the leg. This diagnosis was confirmed by high bromine-levels in the blood. Topical occlusive treatment with glucocorticosteroids was successfull.

Influence of DEAE-dextran, polybrene, dextran and dextran sulphate on spontaneous leukaemia development in AKR mice and virus induced leukaemia in BALB-c mice.

AKR mice of which more than 90% die of lymphatic thymus leukaemia, had their mean survival time increased by weekly intraperitoneal inoculation of either of the two polycations DEAE-dextran and polybrene. Administration of the neutral dextran had no effect, whereas the polyanion dextran sulphate accelerated leukaemia development.Adult BALB/c mice infected with Rauscher leukaemia virus and treated from the time of palpable spleen enlargement, showed a life prolonging effect of the polycations DEAE/dextran and polybrene, and of neutral dextran. BALB/c mice treated from the time of leukaemia infection, however, showed a life prolonging effect with polyanion dextran sulphate and also of neutral dextran.