When the protein or calcium homeostasis of the endoplasmic reticulum (ER) is adversely altered, cells experience ER stress that leads to various diseases including neurodegeneration. Genetic deletion ...of an ER stress downstream effector, CHOP, significantly protects neuron somata and axons. Here we report that three tricyclic compounds identified through a small-scale high throughput screening using a CHOP promoter-driven luciferase cell-based assay, effectively inhibit ER stress by antagonizing their common target, histamine receptor H1 (HRH1). We further demonstrated that systemic administration of one of these compounds, maprotiline, or CRISPR-mediated retinal ganglion cell (RGC)-specific HRH1 inhibition, delivers considerable neuroprotection of both RGC somata and axons and preservation of visual function in two mouse optic neuropathy models. Finally, we determine that maprotiline restores ER homeostasis by inhibiting HRH1-mediated Ca
release from ER. In this work we establish maprotiline as a candidate neuroprotectant and HRH1 as a potential therapeutic target for glaucoma.
Development of new therapeutics against Select Agents such as Francisella is critical preparation in the event of bioterrorism. Testing FDA-approved drugs for this purpose may yield new activities ...unrelated to their intended purpose and may hasten the discovery of new therapeutics. A library of 420 FDA-approved drugs was screened for antibiofilm activity against a model organism for human tularemia, Francisella (F.) novicida, excluding drugs that significantly inhibited growth. The initial screen was based on the 2-component system (TCS) dependent biofilm effect, thus, the QseC dependence of maprotiline anti-biofilm action was demonstrated. By comparing their FDA-approved uses, chemical structures, and other properties of active drugs, toremifene and polycyclic antidepressants maprotiline and chlorpromazine were identified as being highly active against F. novicida biofilm formation. Further down-selection excluded toremifene for its membrane active activity and chlorpromazine for its high antimicrobial activity. The mode of action of maprotiline against F. novicida was sought. It was demonstrated that maprotiline was able to significantly down-regulate the expression of the virulence factor IglC, encoded on the Francisella Pathogenicity Island (FPI), suggesting that maprotiline is exerting an effect on bacterial virulence. Further studies showed that maprotiline significantly rescued F. novicida infected wax worm larvae. In vivo studies demonstrated that maprotiline treatment could prolong time to disease onset and survival in F. novicida infected mice. These results suggest that an FDA-approved drug such as maprotiline has the potential to combat Francisella infection as an antivirulence agent, and may have utility in combination with antibiotics.
Nav1.7 channels are mainly distributed in the peripheral nervous system. Blockade of Nav1.7 channels with small-molecule inhibitors in humans might provide pain relief without affecting the central ...nervous system. Based on the facts that many reported Nav1.7-selective inhibitors contain aryl sulfonamide fragments, as well as a tricyclic antidepressant, maprotiline, has been found to inhibit Nav1.7 channels, we designed and synthesized a series of compounds with ethanoanthracene and aryl sulfonamide moieties. Their inhibitory activity on sodium channels were detected with electrophysiological techniques. We found that compound 10o potently inhibited Nav1.7 channels stably expressed in HEK293 cells (IC
= 0.64 ± 0.30 nmol/L) and displayed a high Nav1.7/Nav1.5 selectivity. In mouse small-sized dorsal root ganglion neurons, compound 10o (10, 100 nmol/L) dose-dependently decreased the sodium currents and dramatically suppressed depolarizing current-elicited neuronal discharge. Preliminary in vivo experiments showed that compound 10o possessed good analgesic activity: in a mouse visceral pain model, administration of compound 10o (30-100 mg/kg, i.p.) effectively and dose-dependently suppressed acetic acid-induced writhing.
The synthesis of a diverse library of compounds structurally related to maprotiline, a norepinephrine reuptake transporter (NET) selective antidepressant which has recently been identified as a novel ...in vitro antiproliferative agent against Burkitt's lymphoma (BL) cell lines is reported. A series of 9,10-dihydro-9,10-ethanoanthracenes were synthesised with modifications to the bridge of the dihydroethanoanthracene structure and with alterations to the basic side chain. A number of compounds were found to reduce cell viability to a greater extent than maprotiline in BL cell lines. In addition a related series of novel 9-substituted anthracene compounds were investigated as intermediates in the synthesis of 9,10-dihydro-9,10-ethanoanthracenes. These compounds proved the most active from the screen and were found to exert a potent caspase-dependant apoptotic effect in the BL cell lines, while having minimal effect on the viability of peripheral blood mononuclear cells (PBMCs). Compounds also displayed activity in multi-drug resistant (MDR) cells.
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•Synthesis of a diverse library of novel anti-depressant analogues.•Antiproliferative effects of maprotiline analogues in Burkitt's lymphoma cell lines.•Apoptotic cell death caspase-dependant.•Antiproliferative effects in multi-drug resistant cells.
The melastatin-related transient receptor potential (TRP) channel TRPM3 is a nonselective cation channel expressed in nociceptive neurons and activated by heat. Because TRPM3-deficient mice show ...inflammatory thermal hyperalgesia, pharmacological inhibition of TRPM3 may exert antinociceptive properties. Fluorometric Ca influx assays and a compound library containing approved or clinically tested drugs were used to identify TRPM3 inhibitors. Biophysical properties of channel inhibition were assessed using electrophysiological methods. The nonsteroidal anti-inflammatory drug diclofenac, the tetracyclic antidepressant maprotiline, and the anticonvulsant primidone were identified as highly efficient TRPM3 blockers with half-maximal inhibition at 0.6 to 6 μM and marked specificity for TRPM3. Most prominently, primidone was biologically active to suppress TRPM3 activation by pregnenolone sulfate (PregS) and heat at concentrations markedly lower than plasma concentrations commonly used in antiepileptic therapy. Primidone blocked PregS-induced Cai influx through TRPM3 by allosteric modulation and reversibly inhibited atypical inwardly rectifying TRPM3 currents induced by coapplication of PregS and clotrimazole. In vivo, analgesic effects of low doses of primidone were demonstrated in mice, applying PregS- and heat-induced pain models, including inflammatory hyperalgesia. Thus, applying the approved drug at concentrations that are lower than those needed to induce anticonvulsive effects offers a shortcut for studying physiological and pathophysiological roles of TRPM3 in vivo.
Background and purpose:
Cannabis is the source of at least seventy phytocannabinoids. The pharmacology of most of these has been little investigated, three notable exceptions being Δ
9
...‐tetrahydrocannabinol, cannabidiol and Δ
9
‐tetrahydrocannabivarin. This investigation addressed the question of whether the little‐studied phytocannabinoid, cannabigerol, can activate or block any G protein‐coupled receptor.
Experimental approach:
The
35
SGTPγS binding assay, performed with mouse brain membranes, was used to test the ability of cannabigerol to produce G protein‐coupled receptor activation or blockade. Its ability to displace
3
HCP55940 from mouse CB
1
and human CB
2
cannabinoid receptors and to inhibit electrically evoked contractions of the mouse isolated vas deferens was also investigated.
Key results:
In the brain membrane experiments, cannabigerol behaved as a potent α
2
‐adrenoceptor agonist (EC
50
= 0.2 nM) and antagonized the 5‐HT
1A
receptor agonist,
R
‐(+)‐8‐hydroxy‐2‐(di‐
n
‐propylamino)tetralin (apparent
K
B
= 51.9 nM). At 10 µM, it also behaved as a CB
1
receptor competitive antagonist. Additionally, cannabigerol inhibited evoked contractions of the vas deferens in a manner that appeared to be α
2
‐adrenoceptor‐mediated (EC
50
= 72.8 nM) and displayed significant affinity for mouse CB
1
and human CB
2
receptors.
Conclusions and implications:
This investigation has provided the first evidence that cannabigerol can activate α
2
‐adrenoceptors, bind to cannabinoid CB
1
and CB
2
receptors and block CB
1
and 5‐HT
1A
receptors. It will now be important to investigate why cannabigerol produced signs of agonism more potently in the
35
SGTPγS binding assay than in the vas deferens and also whether it can inhibit noradrenaline uptake in this isolated tissue and in the brain.
There have been few comparisons of strains and antidepressants in the unpredictable chronic mild stress (UCMS) paradigm in mice. This study was undertaken to determine the influence of such factors ...using four antidepressants drugs including the tricyclics imipramine (20
mg/(kg
day)) and desipramine (10
mg/(kg
day)), the tetracyclic maprotiline (20
mg/(kg
day)) and the selective serotonin reuptake inhibitor (SSRI) fluoxetine (10
mg/(kg
day)) in both Swiss and BALB/c mice. A 6-week UCMS regimen induced deterioration of the coat state and decreased grooming behaviours in the splash test in BALB/c mice but not Swiss mice. The four antidepressants reversed the UCMS-induced effects in BALB/c mice in both measures. However, imipramine and fluoxetine reached significance in the splash test while desipramine and maprotiline displayed only a trend. In conclusion, these results emphasize that BALB/c mice are more sensitive than Swiss mice for studying the effects of the UCMS model as well as for testing antidepressant-like properties.
High genetic and phenotypic variability between
species and strains within species make the development of broad-spectrum antileishmanial drugs challenging. Thus, screening panels consisting of ...several diverse
species can be useful in enabling compound prioritization based on their spectrum of activity. In this study, a robust and reproducible high content assay was developed, and 1280 small molecules were simultaneously screened against clinically relevant cutaneous and visceral species:
,
, and
. The assay is based on THP-1 macrophages infected with stationary phase promastigotes and posterior evaluation of both compound antileishmanial activity and host cell toxicity. The profile of compound activity was species-specific, and out of 51 active compounds, only 14 presented broad-spectrum activity against the three species, with activities ranging from 52% to 100%. Notably, the compounds CB1954, Clomipramine, Maprotiline, Protriptyline, and ML-9 presented pan-leishmanial activity, with efficacy greater than 70%. The results highlight the reduced number of compound classes with pan-leishmanial activity that might be available from diversity libraries, emphasizing the need to screen active compounds against a panel of species and strains. The assay reported here can be adapted to virtually any
species without the need for genetic modification of parasites, providing the basis for the discovery of broad spectrum anti-leishmanial agents.
Resistance to chemotherapy is a major obstacle for the success of cancer therapy and is most commonly attributed to the inability of cancer cells to die by apoptosis, the archetypal programed cell ...death (PCD) response. The development of anticancer drugs that can overcome this resistance to apoptosis and induce other forms of cell death is therefore paramount for efficient cancer therapy. We report that the antidepressants maprotiline and fluoxetine induce autophagic PCD in the chemoresistant Burkitt's lymphoma (BL) cell line DG‐75, which does not involve caspases, DNA fragmentation or PARP cleavage, but is associated with the development of cytoplasmic vacuoles, all consistent with an autophagic mode of PCD. Autophagic PCD was confirmed by transmission electron microscopy, upregulation of Beclin‐I and the extent of PCD being reduced by the autophagic inhibitor 3‐MA. In contrast, these compounds induced apoptotic PCD in the biopsy‐like chemosensitive BL MUTU‐I cell line. We provide evidence that the chemoresistant DG‐75 cells do not express the proapoptotic Bcl‐2 proteins Bax and Bak, show diminished levels of stored intracellular calcium and display shortened rod‐like mitochondria, all of which are known to be associated with a defective “apoptotic” response in cancer cells. PCD in the two cell lines has different Ca2+ responses to maprotiline and fluoxetine, which may also account for their differential PCD responses. Our study, therefore, supports a new mechanistic role for maprotiline and fluoxetine as novel proautophagic agents in the treatment of resistant BL, and thus an alternative therapeutic application for these compounds.
A potentiometric ion selective electrode (ISE) was developed to determine the maprotiline, a tetracyclic pharmaceutical drug substance. Maprotiline-Tetraphenylborate ion pair was synthesized. ...Elemental analysis results showed that combination rate of Maprotiline-Tetraphenylborate ion pair was 1:1. The synthesized ion pair was used as sensing material in the structure of the electrode membrane. For membrane optimization, Polyvinylchloride (PVC) membrane ion selective electrodes were fabricated in different compositions using the synthesized ion pair and the potentiometric performance properties of these electrodes were investigated. We found that an electrode with a composition of 3.0% Maprotiline-Tetraphenylborate ion pair, 65.0% Dibutylphthalate, 32.0% Polyvinylchloride exhibited the best potentiometric performance properties. The linear working range of this electrode was 1.0 × 10−5–1.0 × 10−2 M and slope in 10-fold concentration change was 55.4 mV; detection limit was 5.0 × 10−6 M, pH working range was 3–5; and finally response time was 5 s. The electrode has demonstrated a highly repeatable potentiometric response. The maprotiline content of two different pharmaceutical tablets that are used to treat depression was determined using this electrode. The obtained results were compared with the results obtained by the GC method, which is our comparison method. We found that the results obtained using the potentiometric technique is consistent with the results obtained using GC method at 95% confidence level.
•A potentiometric ion selective electrode was developed to determine the maprotiline.•Polyvinylchloride (PVC) membrane ion selective electrodes were fabricated based on ion pairs of maprotiline.•The electrode was successfully applied for the determination of maprotiline in some pharmaceutical formulations.
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