Agonist Properties Research Articles

Coumarin-Fatty Acid Conjugates as Potential ERα/AKT-1 Antagonists for ER Positive Breast Cancer.

Current drugs used for the treatment of hormone-dependent breast cancer function as anti-estrogens in the breast, in addition to Estrogen Receptor (ER) agonists in the uterus, thus elevate a woman's risk of developing uterine cancer. This is due to the lack of selective binding and partial agonistic effect of these drugs towards estrogen receptors. In recent years, therefore, researchers have turned their attention towards antiestrogens devoid of these agonist properties and thus have a mechanism of action different from the existing drugs. In this context, we report here the design, development and in vitro evaluation of some novel pharmacophores containing coumarin and fatty acid scaffolds for their anti-breast cancer activity. A library of coumarin-fatty acid conjugates was designed using structure-based drug design approach. The conjugates which have shown good in silico results were then synthesized, characterized and evaluated for their anti-breast cancer activity by MTT assay, Apoptotic assay, Cell proliferation assay, Estrogen binding assay and Gene expression study. Out of the fifteen compounds screened, two compounds, SAC-2 and LNAC-2, showed good activity with IC50 values 22µg/ml, 25μg/ml, respectively. These compounds suppressed the proliferation of ER overexpressed MCF-7 cells, increased ERα degradation and hence inactivate the ERα pathway. ER binding assay and gene expression RT-PCR study reveal that SAC-2 downregulated the expression of ERα receptor and AKT-1 gene. Compound SAC-2 is a good antagonist to ER and hence has a potential for treating breast cancer and other cancers where AKT plays an important role.

Involvement of Histamine 2 Receptor in Alpha 1 Adrenoceptor Mediated Cardiac Hypertrophy and Oxidative Stress in H9c2 Cardio Myoblasts.

Despite the involvement of ɑ1adrenergic (ɑ1AR) and Histamine 2 receptors (H2R) in cardiac hypertrophy (CH), their relationship is yet to be studied. Our study investigated interrelationship between them using in vitro CH model. H9c2 cardiomyoblasts were exposed to phenylephrine (ɑ1AR agonist-50μM) in the presence, the absence of famotidine (H2R antagonist-10μM) and BAY 11-7082 (NF-kB inhibitor-10μM). The impact of ɑ1AR stimulation on H2R expression and oxidative stress was assessed. Hypertrophic indices were assessed from activities of enzymatic mediators of cardiac hypertrophy, total protein content, BNP levels and cell volume. Additionally, the inverse agonistic property of famotidine and NFkB activity was also studied. ɑ1AR-induced H2R expression, oxidative stress and hypertrophic indices were significantly abolished by famotidine and pharmacological inhibitor of NFkB. Increase in constitutive activity of H2R was noticed correlating with increased receptor population. These results suggest involvement of NFkB-mediated upregulation of H2R in ɑ1AR-mediated CH.

Prophylactic norepinephrine infusion or leg wrapping for postspinal hypotension in elective caesarean delivery: A randomised, double-blind, placebo-controlled trial.

Because of its alpha and beta agonist properties, norepinephrine infusion is currently being studied for the prevention of spinal hypotension during caesarean delivery. Vasopressor infusions are not always possible if there is an unavailability of infusion pumps. Leg wrapping with crepe bandage is an effective technique for prevention of postspinal hypotension and could be useful in resource-poor settings. The aim of this study was to compare the incidence of hypotension with norepinephrine infusion or leg wrapping with a control group in women undergoing caesarean delivery with spinal anaesthesia. Randomised, double-blind, controlled trial. Single centre, tertiary level institute, India.Study period 3 April 2018 to 31 March 2019. One hundred and forty-four women aged 19 to 40 years with a singleton pregnancy. In group Leg Wrapping, crepe bandage was applied tightly from metatarsus to groin. Group Norepinephrine and the control group received sham leg wrapping. In group Norepinephrine, the women received a norepinephrine infusion according to their body weight, while group Leg Wrapping and the control group received a 0.9% normal saline infusion at a similar rate. All three groups received a 500 ml co-load of Ringer's solution over 15 min. Noninvasive SBP was monitored every 2 min until delivery, and every 5 min thereafter. Any hypotensive event (SBP < 20% of baseline) was treated with an intravenous bolus of norepinephrine (7.5 μg). The primary outcome was the incidence of hypotension. The secondary outcomes were performance error measurements, and the incidences of hypertension, bradycardia, norepinephrine rescue bolus and neonatal outcomes. The incidences of hypotension were significantly lower in the norepinephrine infusion group and the leg wrapping groups than the control group (P values 0.021 for both). Performance error calculations showed that SBP was maintained closer to baseline with the norepinephrine infusion. Norepinephrine infusion and leg wrapping can both reduce the incidence of postspinal hypotension during elective caesarean delivery compared with saline infusion alone. Clinical trial number and registry URL: CTRI/2018/04/012917 registered at Clinical Trial Registry of India http://www.ctri.nic.in/Clinicaltrials/login.php.

Characterization of agonist-dependent somatostatin receptor subtype 2 trafficking in neuroendocrine cells.

Somatostatin (SOM) receptor subtype 2 (SSTR2) is the major receptor subtype mediating SOM effects throughout the neuraxis. We previously demonstrated that the non-selective agonist [D-Trp8]-SOM induces intracellular sequestration of SSTR2, whereas this receptor is maintained at the cell surface after treatment with the SSTR2-selective agonist L-779,976 in cells co-expressing SSTR2 and SSTR5. In this study, we knocked-out SSTR5 in AtT20 cells endogenously expressing both SSTR2 and SSTR5 and used immuno-labeling and confocal microscopy to investigate the effect of SSTR5 on regulation of SSTR2 trafficking. Our results indicate that unlike [D-Trp8]-SOM-induced intracellular sequestration, L-779,976 stimulation results in the maintenance of SSTR2 at the cell surface regardless of whether SSTR5 is present or not. We then examined the trafficking pathways of SSTR2 upon stimulation by either agonist. We found that both [D-Trp8]-SOM and L-779,976 induce SSTR2 internalization via transferrin-positive vesicles. However, SSTR2 internalized upon L-779,976 treatment undergoes rapid recycling to the plasma membrane, whereas receptors internalized by [D-Trp8]-SOM recycle slowly after washout of the agonist. Furthermore, [D-Trp8]-SOM stimulation induces degradation of a fraction of internalized SSTR2 whereas L-779,976-dependent, rapid SSTR2 recycling appears to protect internalized SSTR2 from degradation. In addition, Octreotide which has preferential SSTR2 affinity, induced differential effects on both SSTR2 trafficking and degradation. Our results indicate that the biased agonistic property of L-779,976 protects against SSTR2 surface depletion by rapidly initiating SSTR2 recycling while SSTR5 does not regulate L-779-976-dependent SSTR2 trafficking.

Beneficial effects of the phytocannabinoid Δ9-THCV in L-DOPA-induced dyskinesia in Parkinson's disease

The antioxidant and CB2 receptor agonist properties of Δ9-tetrahydrocannabivarin (Δ9-THCV) afforded neuroprotection in experimental Parkinson's disease (PD), whereas its CB1 receptor antagonist profile at doses lower than 5 mg/kg caused anti-hypokinetic effects. In the present study, we investigated the anti-dyskinetic potential of Δ9-THCV (administered i.p. at 2 mg/kg for two weeks), which had not been investigated before. This objective was investigated after inducing dyskinesia by repeated administration of L-DOPA (i.p. at 10 mg/kg) in a genetic model of dopaminergic deficiency, Pitx3ak mutant mice, which serves as a useful model for testing anti-dyskinetic agents. The daily treatment of these mice with L-DOPA for two weeks progressively increased the time spent in abnormal involuntary movements (AIMs) and elevated their horizontal and vertical activities (as measured in a computer-aided actimeter), signs that reflected the dyskinetic state of these mice. Interestingly, when combined with L-DOPA from the first injection, Δ9-THCV delayed the appearance of all these signs and decreased their intensity, with a reduction in the levels of FosB protein and the histone pAcH3 (measured by immunohistochemistry), which had previously been found to be elevated in the basal ganglia in L-DOPA-induced dyskinesia. In addition to the anti-dyskinetic effects of Δ9-THCV when administered at the onset of L-DOPA treatment, Δ9-THCV was also effective in attenuating the intensity of dyskinesia when administered for three consecutive days once these signs were already present (two weeks after the onset of L-DOPA treatment). In summary, our data support the anti-dyskinetic potential of Δ9-THCV, both to delay the occurrence and to attenuate the magnitude of dyskinetic signs. Although further studies are clearly required to determine the clinical significance of these data in humans, the results nevertheless situate Δ9-THCV in a promising position for developing a cannabinoid-based therapy for patients with PD.

Selective Progesterone Receptor Modulators-Mechanisms and Therapeutic Utility.

Selective progesterone receptor modulators (SPRMs) are a new class of compounds developed to target the progesterone receptor (PR) with a mix of agonist and antagonist properties. These compounds have been introduced for the treatment of several gynecological conditions based on the critical role of progesterone in reproduction and reproductive tissues. In patients with uterine fibroids, mifepristone and ulipristal acetate have consistently demonstrated efficacy, and vilaprisan is currently under investigation, while studies of asoprisnil and telapristone were halted for safety concerns. Mifepristone demonstrated utility for the management of endometriosis, while data are limited regarding the efficacy of asoprisnil, ulipristal acetate, telapristone, and vilaprisan for this condition. Currently, none of the SPRMs have shown therapeutic success in treating endometrial cancer. Multiple SPRMs have been assessed for efficacy in treating PR-positive recurrent breast cancer, with in vivo studies suggesting a benefit of mifepristone, and multiple in vitro models suggesting the efficacy of ulipristal acetate and telapristone. Mifepristone, ulipristal acetate, vilaprisan, and asoprisnil effectively treated heavy menstrual bleeding (HBM) in patients with uterine fibroids, but limited data exist regarding the efficacy of SPRMs for HMB outside this context. A notable class effect of SPRMs are benign, PR modulator-associated endometrial changes (PAECs) due to the actions of the compounds on the endometrium. Both mifepristone and ulipristal acetate are effective for emergency contraception, and mifepristone was approved by the US Food and Drug Administration (FDA) in 2012 for the treatment of Cushing’s syndrome due to its additional antiglucocorticoid effect. Based on current evidence, SPRMs show considerable promise for treatment of several gynecologic conditions.

친환경적 살충제 개발을 위한 비스테로이드성 Ecdysone 작용제들의 화학구조 특성 비교 연구

The relationship between physicochemical and molecular structural properties of non-steroidal ecdysone agonists and their bioactivity was investigated in this study. 2 Dibenzoylhydrazines including RH 5849 and tebufenozide, 1 non-dibenzoylhydrazine, DTBHIB and 1 naturally found agonist, 8-O-acetylharpagide were selected and their molecular physicochemical parameter values such as Log P, hydrophilic-lipophilic balance(H.L.B.), hydrogen bond(H.B.), dipole moment(D.M.), and connectivity/kappa index and distribution of electronic charge were calculated/drawn using computer program to be compared. DTBHIB showed physicochemical and steric properties more similar to dibenzoylhydrazines than 8-O-acetylharpagide. Overally, non-steroidal ecdysone agonists showed an increasing tendency of bioactivity with the increase of their hydrophobicity within a certain range. It was also shown that dibenzoylhydrazines and DTBHIB share the common distribution pattern of molecular electronic charge which is offered by -C=O linked with the left benzene ring. These results suggest that bioactivity of non-steroidal ecdysone agonists is affected combinedly by physico-chemical properties such as hydrophilicity of the ligand, position and steric orientation of functional groups and distribution of electronic charge in the molecule, not only by the number of -OH in the molecule and resulting possibility of hydrogen bond with receptors.

Characterization of 7A5: A Human CD137 (4-1BB) Receptor Binding Monoclonal Antibody with Differential Agonist Properties That Promotes Antitumor Immunity.

The CD137 receptor plays a key role in mediating immune response by promoting T cell proliferation, survival, and memory. Effective agonism of CD137 has the potential to reinvigorate potent antitumor immunity either alone or in combination with other immune-checkpoint therapies. In this study, we describe the discovery and characterization of a unique CD137 agonist, 7A5, a fully human IgG1 Fc effector-null monoclonal antibody. The biological properties of 7A5 were investigated through in vitro and in vivo studies. 7A5 binds CD137, and the binding epitope overlaps with the CD137L binding site based on structure. 7A5 engages CD137 receptor and activates NF-κB cell signaling independent of cross-linking or Fc effector function. In addition, T cell activation measured by cytokine IFNγ production is induced by 7A5 in peripheral blood mononuclear cell costimulation assay. Human tumor xenograft mouse models reconstituted with human immune cells were used to determine antitumor activity in vivo. Monotherapy with 7A5 inhibits tumor growth, and this activity is enhanced in combination with a PD-L1 antagonist antibody. Furthermore, the intratumoral immune gene expression signature in response to 7A5 is highly suggestive of enhanced T cell infiltration and activation. Taken together, these results demonstrate 7A5 is a differentiated CD137 agonist antibody with biological properties that warrant its further development as a cancer immunotherapy. GRAPHICAL ABSTRACT: http://mct.aacrjournals.org/content/molcanther/19/4/988/F1.large.jpg.

Antiviral, Immunomodulatory and Antiproliferative Activities of Recombinant Soluble IFNAR2 without IFN-ß Mediation.

Soluble receptors of cytokines are able to modify cytokine activities and therefore the immune system, and some have intrinsic biological activities without mediation from their cytokines. The soluble interferon beta (IFN-ß) receptor is generated through alternative splicing of IFNAR2 and has both agonist and antagonist properties for IFN-ß, but its role is unknown. We previously demonstrated that a recombinant human soluble IFN-ß receptor showed intrinsic therapeutic efficacy in a mouse model of multiple sclerosis. Here we evaluate the potential biological activities of recombinant sIFNAR2 without the mediation of IFN-ß in human cells. Recombinant sIFNAR2 down-regulated the production of IL-17 and IFN-ɣ and reduced the cell proliferation rate. Moreover, it showed a strong antiviral activity, fully protecting the cell monolayer after being infected by the virus. Specific inhibitors completely abrogated the antiviral activity of IFN-ß, but not that of the recombinant sIFNAR2, and there was no activation of the JAK-STAT signaling pathway. Consequently, r-sIFNAR2 exerts immunomodulatory, antiproliferative and antiviral activities without IFN-ß mediation, and could be a promising treatment against viral infections and immune-mediated diseases.

Antinociceptive effects of potent, selective and brain penetrant muscarinic M4 positive allosteric modulators in rodent pain models

Analgesic properties of orthosteric agonists of the muscarinic M4 receptor subtype have been documented in literature reports, with evidence from pharmacological and in vivo receptor knock out (KO) studies. Constitutive M4 receptor KO mice demonstrated an increased response in the formalin pain model, supporting this hypothesis. Two novel positive allosteric modulators (PAM) of the M4 receptor, Compounds 1 and 2, were characterized in rodent models of acute nociception. Results indicated decreased time spent on nociceptive behaviors in the mouse formalin model, and efficacy in the mouse tail flick assay. The analgesic-like effects of Compounds 1 and 2 were shown to be on target, as the compounds lacked any activity in constitutive M4 KO mice, while retaining activity in wild type control littermates. The analgesic-like effects of Compounds 1 and 2 were significantly diminished in KO mice that have selective deletion of the M4 receptor in neurons that co-express the dopaminergic D1 receptor subtype, suggesting a centrally-mediated effect on nociception. The opioid antagonist naloxone did not diminish the effect of Compound 1, indicating the effects of Compound 1 are not secondarily linked to opioid pathways. Compound 1 was evaluated in the rat, where it demonstrated analgesic-like effects in tail flick and a subpopulation of spinal nociceptive sensitive neurons, suggesting some involvement of spinal mechanisms of nociceptive modulation. These studies indicate that M4 PAMs may be a tractable target for pain management assuming an appropriate safety profile, and it appears likely that both spinal and supraspinal pathways may mediate the antinociceptive-like effects.

7,8-Dihydroxyflavone alleviated the high-fat diet and alcohol-induced memory impairment: behavioral, biochemical and molecular evidence.

Alcoholism and obesity impart a deleterious impact on human health and affects the quality of life. Chronic consumption of alcohol and western diet has been reported to cause memory deficits. 7,8-dihydroxyflavone (7,8-DHF), a TrkB agonist, comprises antioxidant and anti-inflammatory properties in treating various neurological disorders. The current study was aimed to determine the protective effect and molecular mechanism of 7,8-DHF against alcohol and high-fat diet (HFD)-induced memory deficits in rats. The adult male Wistar rats were given alcohol (3-15%) and HFD ad libitum for 12weeks in different experimental groups. 7,8-DHF (5mg/kg) was intraperitoneally injected daily for the last 4weeks (9th-12th week). The alcohol and HFD administration caused cognitive impairment as evaluated through the Morris water maze (MWM) test in alcohol, HFD, and alcohol + HFD-fed animals. The last 4-week treatment of 7,8-DHF (5mg/kg; i.p.) attenuated alcohol and HFD-induced memory loss. 7,8-DHF treatment also restored the glutathione (GSH) level along with attenuation of nitrite, malondialdehyde content (markers of oxidative and nitrosative stress), and reduction of the acetylcholinesterase activity in the hippocampus of alcohol and HFD-fed animals. Furthermore, the administration of 7,8-DHF caused downregulation of NF-κB, iNOS, and caspase-3 and upregulation of Nrf2, HO-1, and BDNF mRNA level in rat hippocampus. 7,8-DHF administration conferred beneficial effects against alcohol and HFD-induced memory deficit via its unique antioxidant, anti-inflammatory, anti-apoptotic potential, along with the activation of TrkB/BDNF signaling pathway in the hippocampus.

Regiospecific Introduction of Halogens on the 2-Aminobiphenyl Subunit Leading to Highly Potent and Selective M3 Muscarinic Acetylcholine Receptor Antagonists and Weak Inverse Agonists.

Muscarinic M3 receptor antagonists and inverse agonists displaying high affinity and subtype selectivity over the antitarget M2 are valuable pharmacological tools and may enable improved treatment of chronic obstructive pulmonary disease (COPD), asthma, or urinary incontinence. On the basis of known M3 antagonists comprising a piperidine or quinuclidine unit attached to a biphenyl carbamate, 5-fluoro substitution was responsible for M3 subtype selectivity over M2, while 3'-chloro substitution substantially increased affinity through a σ-hole interaction. Resultantly, two piperidinyl- and two quinuclidinium-substituted biphenyl carbamates OFH243 (13n), OFH244 (13m), OFH3911 (14n), and OFH3912 (14m) were discovered, which display two-digit picomolar affinities with Ki values from 0.069 to 0.084 nM, as well as high selectivity over the M2 subtype (46- to 68-fold). While weak inverse agonistic properties were determined for the biphenyl carbamates 13m and 13n, neutral antagonism was observed for 14m and 14n and tiotropium under identical assay conditions.

A CASE OF TARDIVE DYSKINESIA (TD) IN A PATIENT WITH NON SQUAMOUS CELL CARCINOMA BEING TREATED WITH ARIPIPRAZOLE

Introduction Aripiprazole is an atypical antipsychotic that is usually well tolerated. It is FDA approved for treatment for schizophrenia and mania in Bipolar Disorder. Off label use includes augmentation protocols for depression and anxiety disorders as well as aggression in the pediatric population. Properties include 5-HT1A partial agonism and 5HT1-A antagonism along with D2 and D3 agonism. Abilify is often preferred due to reduced risk of metabolic syndrome, extrapyramidal symptoms and minimal sedative profile. Second generation antipsychotics are usually preferred for their “better” side effect profile as far as extrapyramidal symptoms such as tardive dyskinesia is concerned. Methods This is a case study regarding an outpatient. Literature review regarding this topic is also provided.We describe a patient with history of Non Squamous Cell Carcinoma (NSCC) of lung who developed overt symptoms and signs of tardive dyskinesia secondary to initiation of aripiprazole which suggests need for monitoring for TD even with atypical antipsychotics Results Aripiprazole being a partial dopamine agonist rather than being a full dopamine agonist allows for increase dopamine release in areas of the brain which are hypofunctioningand for dampening of dopaminergic activity in areas which are hyperfunctioning.At a therapeutic dose, it is noteworthy that aripiprazole has one of the highest D2 receptor affinities; however because of its partial agonist properties, it has a lower risk of causing acute EPS and probably TD. Special considerations for medicating elderly patients with psychosis on antipsychotics should include utilization of a screening tool such as the abnormal involuntary movement questionnaire (AIMS) to detect TD at its earliest and take active measures to prevent worsening of symptoms. Conclusions Further research is required to identify the specific dopaminergic pathway responsible for induction of tardive dyskinesia in patients which can lead to more specific therapeutic targets without this side effect with aripiprazole. We suggest dosing for shorter periods of time especially when utilizing aripiprazole as an augmenting agent for depression or anxiety or off- clinical use. In theory, SGAs are safer in terms of tardive dyskinesia however our case study underlies the need for informed consent and psychoeducation regarding this side effect. This research was funded by: No funding was received

Effects of Liraglutide on Myocardial Function After Cardiac Surgery: A Secondary Analysis of the Randomised Controlled GLOBE Trial.

Introduction: Previous studies demonstrated the cardioprotective properties of glucagon-like peptide-1 receptor agonists in patients with diabetes or cardiac disease. We investigated whether preoperative subcutaneous liraglutide improves myocardial function after cardiac surgery. Methods: We performed a pre-planned secondary analysis of adult patients undergoing cardiac surgery included in the GLOBE trial. Patients were randomised to receive 0.6 mg subcutaneous liraglutide on the evening before surgery and 1.2 mg after induction of anaesthesia, or matching placebo. Perioperative echocardiographic assessments, haemodynamic parameters, doses of vasoactive inotropic support and postoperative measurements of troponin, Creatine Kinase-MB , creatinine and lactate were compared between groups. Results: The study population consisted of the entire intention-to-treat cohort of the GLOBE trial. In this study, 129 patients received liraglutide and 132 patients placebo. Baseline characteristics were comparable between groups. Postoperatively, 170 (65%) patients underwent echocardiography. In the liraglutide group, more patients had a normal left ventricular systolic function (68%, 59 patients) compared to placebo (53%, 44 patients), difference = 15%, 95%CI = 0–30, p = 0.049. Assessment of the right ventricle revealed no difference in function. Conclusions: Patients receiving short-term preoperative liraglutide treatment better maintained normal myocardial function after cardiac surgery. This study warrants further evaluation of the potential beneficial effects of GLP-1 receptor agonists in cardiac surgery patients.

Preclinical Assessment of the Analgesic Pharmacology of NKTR-181 in Rodents.

Pharmacological evaluation of the mu-opioid receptor (MOR) agonist properties of NKTR-181 in rodent models. Graded noxious stimulus intensities were used in rats to establish the antinociceptive potency and efficacy of NKTR-181 relative to morphine, fentanyl, and oxycodone. Characteristics of MOR agonist actions, as measured by antinociceptive tolerance and cross-tolerance, as well as opioid-induced hyperalgesia (OIH) and naloxone-precipitated withdrawal in NKTR-181- and morphine-dependent in mice, were compared. NKTR-181 showed dose- and time-related antinociception with similar maximal effects to morphine in the rat and mouse hot-water tail-flick test. No sex or species differences were observed in NKTR-181 or morphine antinociception. Rats treated with NKTR-181 and morphine exhibited decreases in both potency and maximal efficacy as nociceptive stimulus intensity was increased from a water temperature of 50°C to 54°C. Evaluation of antinociception at a high stimulus intensity revealed that oxycodone and fentanyl exhibited greater efficacy than either NKTR-181 or morphine. The relative potency difference between NKTR-181 and morphine across all tail-flick studies was determined to be 7.6-fold (90% confidence interval, 2.6, 21.5). The peak antinociceptive effect of NKTR-181 was delayed compared to that of the other opioids and cumulative drug effects were not observed. Repeated treatment with escalating, approximately equi-analgesic doses of NKTR-181 or morphine, produced antinociceptive tolerance and cross-tolerance. Under these pharmacological conditions, OIH and naloxone-precipitated physical dependence were similar for NKTR-181 and morphine. NKTR-181 had a slower onset, but similar efficacy, to morphine in the models studied supporting reduced abuse potential while maintaining analgesic effect in comparison with current opioids.

Ecotoxicological equilibria of triclosan in Microtox, XenoScreen YES/YAS, Caco2, HEPG2 and liposomal systems are affected by the occurrence of other pharmaceutical and personal care emerging contaminants

Contaminants of emerging concern may be considered as any chemicals or factors whose unintended continuous release and persistence in the environment may lead to any observable undesirable response of living beings. Still not much is known on reciprocal toxicological impact of given chemicals when present in binary or more complex mixtures. In this work, an attempt was thus undertaken to study the impact of butylparaben, methylparaben and diclofenac on toxicological behavior and properties of triclosan (at varying concentration levels) with respect to Microtox, XenoScreen YES/YAS, Caco-2, HEPG2, and liposomal systems.Having performed analytical and biological studies modeling was done using two modeling approaches, viz., concentration addition (CA) and independent action (IA) at three concentration levels of each chemical studied. The effect of the highest concentration of triclosan studied was impacted by even small amounts of methylparaben and butylparaben in Microtox while diclofenac preferably affected triclosan activity at its lowest concentration level (with CA model). Estrogenic agonistic properties of triclosan were severely impacted by both parabens in an antagonistic way; diclofenac showed in all cases underestimation or synergy at the lowest triclosan concentration studied. Estrogenic antagonistic activity of triclosan was also slightly affected by parabens and by diclofenac in binary mixtures, showing overestimation and antagonist effects. HepG2 cells appeared to be the most resistant to the toxic effect of the mixtures at the concentrations tested and no significant proof of synergy or antagonism could be detected with the MTT assay. The liposome assays on the mixtures followed the same trends obtained with the MTT assay with Caco-2 cells, confirming the validity of the in vitro model used in this research. As studies on emerging contaminants mixtures toxicity are still scarce, research presented here constitute an important part in confirming utility and versatility of emerging contaminants modeling in environmental toxicology.

A closer look into NADPH oxidase inhibitors: Validation and insight into their mechanism of action

NADPH-oxidases (NOXs) purposefully produce reactive-oxygen-species (ROS) and are found in most kingdoms of life. The seven human NOXs are each characterized by a specific expression profile and a fine regulation to spatio-temporally tune ROS concentration in cells and tissues. One of the best known roles for NOXs is in host protection against pathogens but ROS themselves are important second messengers involved in tissue regeneration and the modulation of pathways that induce and sustain cell proliferation. As such, NOXs are attractive pharmacological targets in immunomodulation, fibrosis and cancer. We have studied an extensive number of available NOX inhibitors, with the specific aim to identify bona fide ligands versus ROS-scavenging molecules. Accordingly, we have established a comprehensive platform of biochemical and biophysical assays. Most of the investigated small molecules revealed ROS-scavenging and/or assay-interfering properties to various degrees. A few compounds, however, were also demonstrated to directly engage one or more NOX enzymes. Diphenylene iodonium was found to react with the NOXs’ flavin and heme prosthetic groups to form stable adducts. We also discovered that two compounds, VAS2870 and VAS3947, inhibit NOXs through the covalent alkylation of a cysteine residue. Importantly, the amino acid involved in covalent binding was found to reside in the dehydrogenase domain, where the nicotinamide ring of NADPH is bound. This work can serve as a springboard to guide further development of bona fide ligands with either agonistic or antagonistic properties toward NOXs.

Novel pyrrolidinone derivative lacks claimed histamine H3 receptor stimulation in receptor binding and functional studies

Since the discovery and early characterization of the histamine H3 receptor (H3R) in the 1980′s, predominantly imidazole-based agonists were presented to the scientific community such as Nα-methylhistamine (Nα-MeHA) or (R)-α-methylhistamine ((R)α-MeHA). Whereas therapeutic applications have been prompted for H3R agonists such as treatment of pain, asthma and obesity, several drawbacks associated with imidazole-containing ligands makes the search for new agonists for this receptor demanding. Accordingly, high interest arose after publication of several pyrrolidindione-based, highly affine H3R agonists within this journal that avoid the imidazole moiety and thus, presenting a novel type of potential pharmacophores (Ghoshal, Anirban et al., 2018). In our present study performed in two independent laboratories, we further evaluated the exposed lead-compound (EC50 = 0.1 nM) of the previous research project with regards to pharmacological behavior at H3R. Thereby, no binding affinity was observed in neither [3H]Nα-MeHA nor bodilisant displacement assays that contradicts the previously published activity. Additional functional exploration employing GTPγ[35S], cAMP-accumulation assay and cAMP response element (CRE)-driven reporter gene assays exhibited slight partial agonist properties of such pyrrolidindiones but acting apart from the reported concentration range. We conclude, that the previously reported actions of such pyrrolidindiones result from an overestimation based on the method of measurement and thus, we cast doubt on the new pharmacophores with H3R agonist activity.

Towards an Understanding of the Mode of Action of Human Aromatase Activity for Azoles through Quantum Chemical Descriptors-Based Regression and Structure Activity Relationship Modeling Analysis

Aromatase is an enzyme member of the cytochrome P450 superfamily coded by the CYP19A1 gene. Its main action is the conversion of androgens into estrogens, transforming androstenedione into estrone and testosterone into estradiol. This enzyme is present in several tissues and it has a key role in the maintenance of the balance of androgens and estrogens, and therefore in the regulation of the endocrine system. With regard to chemical safety and human health, azoles, which are used as agrochemicals and pharmaceuticals, are potential endocrine disruptors due to their agonist or antagonist interactions with the human aromatase enzyme. This theoretical study investigated the active agonist and antagonist properties of “chemical classes of azoles” to determine the relationships of azole interaction with CYP19A1, using stereochemical and electronic properties of the molecules through classification and multilinear regression (MLR) modeling. The antagonist activities for the same substituent on diazoles and triazoles vary with its chemical composition and its position and both heterocyclic systems require aromatic substituents. The triazoles require the spherical shape and diazoles have to be in proper proportion of the branching index and the number of ring systems for the inhibition. Considering the electronic aspects, triazole antagonist activity depends on the electrophilicity index that originates from interelectronic exchange interaction (ωHF) and the LUMO energy (), and the diazole antagonist activity originates from the penultimate orbital () of diazoles. The regression models for agonist activity show that it is opposed by the static charges but favored by the delocalized charges on the diazoles and thiazoles. This study proposes that the electron penetration of azoles toward heme group decides the binding behavior and stereochemistry requirement for antagonist activity against CYP19A1 enzyme.

The study of hormone-like properties of glioxyren

Aim. To study the possible interaction of glioxyrene (a new diuretic substance – a derivative of 2-oxoindoline-3-glyoxyllic acid) with renal receptors of mineralocorticosteroids; to find out the possible role of the dopamine-like effect in the renal effects of glioxyren, as well as study the effectiveness of the simultaneous use of inhibitors of dopamine receptors and glioxyren.Materials and methods. In the experiment in rats the interaction of glioxyren with peripheral renal receptors of dopamine was studied through the effect of the substance on diuresis under blockade of these receptors with domperidone (a blocker of peripheral receptors of dopamine) in the dose of 50 mg/kg. Diuresis, excretion of sodium and potassium were determined for 2 hours. The effect of glioxyren on the receptors of mineralocorticoids on the background of the partial blockade of these receptors by spironolocton in the oral dose of 20 mg/kg was studied. Water diuresis, excretion of sodium and potassium was studied for 2 hours.Results and discussion. It has been found that there is the stimulation of water diuresis with glioxyrene as a result of strengthening of the renal blood flow, activation of sodium excretion due to inhibition of sodium reabsorption as a result of the effect on the epithelium of the nephron tubules, stimulation of natriurea and reduction of potassium due to inhibition of aldosterone secretion in the adrenal glands.Conclusions. Glioxyren has the properties of a dopamine renal receptor agonist as it causes renal dopaminespecific effects associated with the activation of peripheral dopamine receptors. Glioxyren is not an aldosterone renal receptor antagonist.