Discovery of Dual Aβ/Tau Inhibitors and Evaluation of Their Therapeutic Effect on a Drosophila Model of Alzheimer's Disease

Alzheimer's disease (AD), the most common type of dementia, currently represents an extremely challenging and unmet medical need worldwide. Amyloid-β (Aβ) and Tau proteins are prototypical AD hallmarks, as well as validated drug targets. Accumulating evidence now suggests that they synergistically contribute to disease pathogenesis. This could not only help explain negative results from anti-Aβ clinical trials but also indicate that therapies solely directed at one of them may have to be reconsidered. Based on this, herein, we describe the development of a focused library of 2,4-thiazolidinedione (TZD)-based bivalent derivatives as dual Aβ and Tau aggregation inhibitors. The aggregating activity of the 24 synthesized derivatives was tested in intact Escherichia coli cells overexpressing Aβ42 and Tau proteins. We then evaluated their neuronal toxicity and ability to cross the blood−brain barrier (BBB), together with the in vitro interaction with the two isolated proteins. Finally, the most promising (most active, nontoxic, and BBB-permeable) compounds 22 and 23 were tested in vivo, in a Drosophila melanogaster model of AD. The carbazole derivative 22 (20 μM) showed extremely encouraging results, being able to improve both the lifespan and the climbing abilities of Aβ42 expressing flies and generating a better outcome than doxycycline (50 μM). Moreover, 22 proved to be able to decrease Aβ42 aggregates in the brains of the flies. We conclude that bivalent small molecules based on 22 deserve further attention as hits for dual Aβ/Tau aggregation inhibition in A

Multitarget-directed ligands combining cholinesterase and monoamine oxidase inhibition with histamine H3R antagonism for neurodegenerative diseases

J.M.C. thanks MINECO (SAF2012-33304 and SAF2015-65586-R). J.M.C., F.L.M., and A.R. thank UCJC for grants 2015-12, 2014-35, and 2015-21, respectively. J.E. thanks the Fondo de Investigaciones Sanitarias (FIS) (ISCIII/FEDER) (Programa Miguel Servet: CP14/00008 and PI16/00735) and Fundación Mutua Madrileña. O.S. and J.J. thank MHCZ-DRO (UHHK 00179906) for support. R.R.R., H.S., and J.M.C. acknowledge the EU COST Actions CM1103 and CM15135. E.P. and H.S. thank the German Research Foundation (DFG; PRO 1405/2-2, PRO 1405/4-1, SFB 1039 A07, and INST208/664-1).The therapy of complex neurodegenerative diseases requires the development of multitarget-directed drugs (MTDs). Novel indole derivatives with inhibitory activity towards acetyl/butyrylcholinesterases and monoamine oxidases A/B as well as the histamine H3 receptor (H3R) were obtained by optimization of the neuroprotectant ASS234 by incorporating generally accepted H3R pharmacophore motifs. These small-molecule hits demonstrated balanced activities at the targets, mostly in the nanomolar concentration range. Additional in vitro studies showed antioxidative neuroprotective effects as well as the ability to penetrate the blood–brain barrier. With this promising in vitro profile, contilisant (at 1 mg kg−1 i.p.) also significantly improved lipopolysaccharide-induced cognitive deficits.PostprintPeer reviewe

Understanding travel influences of overnight off-trail trekking: a case study of National Park Slovenský raj, Slovakia

While adventure tourism has attracted attention of scholars, reported research to date is mostly concentrated on marketing. In contrast, research reported here is focused on adventure travellers in the context of visitor management in protected natural areas. Specifically, the aim of this study was to establish relationship between adventure travellers’ motivation, their visiting behaviour, environmental awareness and readiness to compromise their enjoyment in order to minimise adverse environmental impacts. In this, the research was focused on hard-adventurers, that is those that partake in off-trekking and bivouacking that are contrary to the national park visiting rules. The study was conducted in the National Park (NP) Slovenský raj, one of the most popular national parks of Slovakia and Central Europe through visitor survey on attitudes towards the environment, activities, self-reflection and the situational factors. The outcomes indicate that the majority of respondents were willing to forfeit some freedoms if they would be educated on how this would preserve the natural environment. This emphasizes the need for management regulations to be complemented by strong educational strategies aimed at specific type of visitors

The Ability of Tourist Natural Trails to Resist Tourism Load and Possibilities for Reducing the Environmental Impacts : Case Study of the Slovak Paradise National Park (Slovakia)

The strictly protected natural area of Sucha Bela Gorge, located in the Slovak Paradise National Park, Slovakia, is exposed to environmental degradation by heavy tourist loads. Although educational and technical measures have been put in place, there is ongoing debate whether and how to limit the intensity of tourist visits. This study evaluates the ability of the trail leading through the gorge to resist trampling disturbance and to minimise the environmental impacts in the wider area of Sucha Bela by keeping tourists from moving off the designated areas. Aspects of trail layout, geological and geomorphological structures, terrain altering during the summer season, and acceptable tourist flow were investigated.The results show the current development would be acceptable in the case of limited off-trail movement. It therefore seems appropriate to review the trail allocation and marking, and to focus on environmental education rather than on limiting tourist visits

Synthesis of New Biscoumarin Derivatives, In Vitro Cholinesterase Inhibition, Molecular Modelling and Antiproliferative Effect in A549 Human Lung Carcinoma Cells

A series of novel C4-C7-tethered biscoumarin derivatives (12a–e) linked through piperazine moiety was designed, synthesized, and evaluated biological/therapeutic potential. Biscoumarin 12d was found to be the most effective inhibitor of both acetylcholinesterase (AChE, IC50 = 6.30 µM) and butyrylcholinesterase (BChE, IC50 = 49 µM). Detailed molecular modelling studies compared the accommodation of ensaculin (well-established coumarin derivative tested in phase I of clinical trials) and 12d in the human recombinant AChE (hAChE) active site. The ability of novel compounds to cross the blood–brain barrier (BBB) was predicted with a positive outcome for compound 12e. The antiproliferative effects of newly synthesized biscoumarin derivatives were tested in vitro on human lung carcinoma cell line (A549) and normal colon fibroblast cell line (CCD-18Co). The effect of derivatives on cell proliferation was evaluated by MTT assay, quantification of cell numbers and viability, colony-forming assay, analysis of cell cycle distribution and mitotic activity. Intracellular localization of used derivatives in A549 cells was confirmed by confocal microscopy. Derivatives 12d and 12e showed significant antiproliferative activity in A549 cancer cells without a significant effect on normal CCD-18Co cells. The inhibition of hAChE/human recombinant BChE (hBChE), the antiproliferative activity on cancer cells, and the ability to cross the BBB suggest the high potential of biscoumarin derivatives. Beside the treatment of cancer, 12e might be applicable against disorders such as schizophrenia, and 12d could serve future development as therapeutic agents in the prevention and/or treatment of Alzheimer’s disease

Multitarget-directed ligands combining cholinesterase and monoamine oxidase inhibition with histamine H₃R antagonism for neurodegenerative diseases

The therapy of complex neurodegenerative diseases requires the development of multitarget-directed drugs (MTDs). Novel indole derivatives with inhibitory activity towards acetyl/butyrylcholinesterases and monoamine oxidases A/B as well as the histamine H3 receptor (H3R) were obtained by optimization of the neuroprotectant ASS234 by incorporating generally accepted H3R pharmacophore motifs. These small-molecule hits demonstrated balanced activities at the targets, mostly in the nanomolar concentration range. Additional in vitro studies showed antioxidative neuroprotective effects as well as the ability to penetrate the blood–brain barrier. With this promising in vitro profile, contilisant (at 1 mg kg−1 i.p.) also significantly improved lipopolysaccharide-induced cognitive deficits