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Background: Currently, protozoan infectious diseases affect billions of people every year. Their pharmacological treatments offer few alternatives and are restrictive due to undesirable side effects and parasite drug resistance. Objective: In this work, three ontology-based approaches were used to identify shared potential drug targets in five species of protozoa. Methods: In this study, proteomes of five species of protozoa: Entamoeba histolytica (E. histolytica), Giardia lamblia (G. lamblia), Trichomonas vaginalis (T. vaginalis), Trypanosoma cruzi (T. cruzi), and Leishmania mexicana (L. mexicana), were compared through orthology inference using three different tools to identify potential drug targets. Results: Comparing the proteomes of E. histolytica, G. lamblia, T. vaginalis, T. cruzi, and L. mexicana, twelve targets for developing new drugs with antiprotozoal activity were identified. Conclusion: New drug targets were identified by orthology-based analysis; therefore, they could be considered for the development of new broad-spectrum antiprotozoal drugs. Particularly, triosephosphate isomerase emerges as a common target in trypanosomatids and amitochondriate parasites.

29 p.2 fig.-3 tab.-1 graph.abst.+Sup. Inf. 4 p._4 tab., The Ames mutagenicity test constitutes the most frequently used assay to estimate the mutagenic potential of drug candidates. While this test employs experimental results using various strains of Salmonella typhimurium, the vast majority of the published in silico models for predicting mutagenicity do not take into account the test results of the individual experiments conducted for each strain. Instead, such QSAR models are generally trained employing overall labels (i.e., mutagenic and nonmutagenic). Recently, neural-based models combined with multitask learning strategies have yielded interesting results in different domains, given their capabilities to model multitarget functions. In this scenario, we propose a novel neural-based QSAR model to predict mutagenicity that leverages experimental results from different strains involved in the Ames test by means of a multitask learning approach. To the best of our knowledge, the modeling strategy hereby proposed has not been applied to model Ames mutagenicity previously. The results yielded by our model surpass those obtained by single-task modeling strategies, such as models that predict the overall Ames label or ensemble models built from individual strains. For reproducibility and accessibility purposes, all source code and datasets used in our experiments are publicly available., This work was partially supported by the Argentinean National Council of Scientific and Technological Research (CONICET for its acronym in Spanish) [Grant No.PIP 112-2017-0100829], by the National Agency for the Promotion of Research, Technological Development and Innovation of Argentina (AGENCIA I+D+i in Spanish),through the Fund for Scientific and Technological Research (FONCyT for its acronym in Spanish) [Grant No. PICT 2019-03350], by the Universidad Nacional del Sur (UNS), Bahía Blanca, Argentina [Grant No. PGI 24/N042], Ministerio de Economía, Industria y Competitividad, Gobierno de España, under Grant No. RTI2018-096100B-100, and by a Google Latin America Research Award 2021−2022.

The Ames mutagenicity test constitutes the most frequently used assay to estimate the mutagenic potential of drug candidates. While this test employs experimental results using various strains of Salmonella typhimurium, the vast majority of the published in silico models for predicting mutagenicity do not take into account the test results of the individual experiments conducted for each strain. Instead, such QSAR models are generally trained employing overall labels (i.e. mutagenic and non-mutagenic). Recently, neural-based models combined with multi-task learning strategies have yielded interesting results in different domains, given their capabilities to model multi-target functions. In this scenario, we propose a novel neural-based QSAR model to predict mutagenicity that leverages experimental results from different strains involved in the Ames test by means of a multi-task learning approach. To the best of our knowledge, the modeling strategy hereby proposed has not been applied to model Ames mutagenicity previously. The results yielded by our model surpass those obtained by single-task modeling strategies, such as models that predict the overall Ames label or ensemble models built from individual strains. For reproducibility and accessibility purposes, all source code and datasets used in our experiments are publicly available.

More than 1 billion people live in areas endemic for leishmaniasis, which is a relevant threat for public health worldwide. Due to the inadequate treatments, there is an urgent need to develop novel alternative drugs and to validate new targets to fight this disease. One appealing approach is the selective inhibition of protein kinases (PKs), enzymes involved in a wide range of processes along the life cycle of

Artificial intelligence (AI) is an emerging technology that is revolutionizing the discovery of new materials. One key application of AI is virtual screening of chemical libraries, which enables the accelerated discovery of materials with desired properties. In this study, we developed computational models to predict the dispersancy efficiency of oil and lubricant additives, a critical property in their design that can be estimated through a quantity named blotter spot. We propose a comprehensive approach that combines machine learning techniques with visual analytics strategies in an interactive tool that supports domain experts’ decision-making. We evaluated the proposed models quantitatively and illustrated their benefits through a case study. Specifically, we analyzed a series of virtual polyisobutylene succinimide (PIBSI) molecules derived from a known reference substrate. Our best-performing probabilistic model was Bayesian Additive Regression Trees (BART), which achieved a mean absolute error of 5.50±0.34 and a root mean square error of 7.56±0.47, as estimated through 5-fold cross-validation. To facilitate future research, we have made the dataset, including the potential dispersants used for modeling, publicly available. Our approach can help accelerate the discovery of new oil and lubricant additives, and our interactive tool can aid domain experts in making informed decisions based on blotter spot and other key properties.

Multitarget drugs are a promising therapeutic approach against Alzheimer’s disease. In this work, a new family of 5-substituted indazole derivatives with a multitarget profile including cholinesterase and BACE1 inhibition is described. Thus, the synthesis and evaluation of a new class of 5-substituted indazoles has been performed. Pharmacological evaluation includes in vitro inhibitory assays on AChE/BuChE and BACE1 enzymes. Also, the corresponding competition studies on BuChE were carried out. Additionally, antioxi- dant properties have been calculated from ORAC assays. Furthermore, studies of anti-inflammatory proper- ties on Raw 264.7 cells and neuroprotective effects in human neuroblastoma SH-SY5Y cells have been performed. The results of pharmacological tests have shown that some of these 5-substituted indazole derivatives 1–4 and 6 behave as AChE/BuChE and BACE1 inhibitors, simultaneously. In addition, some indazole derivatives showed anti-inflammatory (3, 6) and neuroprotective (1–4 and 6) effects against Ab- induced cell death in human neuroblastoma SH-SY5Y cells with antioxidant properties., This work was supported from Ministerio de Economía, Industria y Competitividad, Gobierno de Espa~na under Grant RTI2018-096100B-100.

Ceftolozane/tazobactam (C/T) has emerged as a potential agent for the treatment of extensively drug-resistant (XDR) Pseudomonas aeruginosa infections. As it is a time-dependent antimicrobial, prolonged infusion may help achieve pharmacokinetic/pharmacodynamic (PK/PD) targets. To compare alternative steady-state concentrations (Css) of C/T in continuous infusion (CI) against three XDR P. aeruginosa ST175 isolates with C/T minimum inhibitory concentration (MIC) values of 2 to 16 mg/L in a hollow-fiber infection model (HFIM). Duplicate 10-day HFIM assays were performed to evaluate Css of C/T in CI: one compared 20 and 45 mg/L against the C/T-susceptible isolate while the other compared 45 and 80 mg/L against the two C/T-non-susceptible isolates. C/T resistance emerged when C/T-susceptible isolate was treated with C/T in CI at a Css of 20 mg/L; which showed a deletion in the gene encoding AmpC β-lactamase. The higher dosing regimen (80 mg/L) showed a slight advantage in effectiveness. The higher dosing regimen has the greatest bactericidal effect, regardless of C/T MIC. Exposure to the suboptimal Css of 20 mg/L led to the emergence of C/T resistance in the susceptible isolate. Antimicrobial regimens should be optimized through C/T levels monitoring and dose adjustments to improve clinical management.

Ceftazidime-avibactam (CZA) has emerged as a promising solution to the lack of new antibiotics against Pseudomonas aeruginosa infections. Data from in vitro assays of CZA combinations, however, are scarce. The objective of our study was to perform a time-kill analysis of the effectiveness of CZA alone and in combination with other antibiotics against a collection of extensively drug-resistant (XDR) P. aeruginosa isolates. Twenty-one previously characterized representative XDR P. aeruginosa isolates were selected. Antibiotic susceptibility was tested by broth microdilution, and results were interpreted using CLSI criteria. The time-kill experiments were performed in duplicate for each isolate. Antibiotics were tested at clinically achievable free-drug concentrations. Different treatment options, including CZA alone and combined with amikacin, aztreonam, meropenem, and colistin, were evaluated to identify the most effective combinations. Seven isolates were resistant to CZA (MIC ≥ 16/4 mg/liter), including four metallo-β-lactamase (MBL)-carrying isolates and two class A carbapenemases. Five of them were resistant or intermediate to aztreonam (MIC ≥ 16 mg/liter). Three isolates were resistant to amikacin (MIC ≥ 64 mg/liter) and one to colistin (MIC ≥ 4 mg/liter). CZA monotherapy had a bactericidal effect in 100% (14/14) of the CZA-susceptible isolates. Combination therapies achieved a greater overall reduction in bacterial load than monotherapy for the CZA-resistant isolates. CZA plus colistin was additive or synergistic in 100% (7/7) of the CZA-resistant isolates, while CZA plus amikacin and CZA plus aztreonam were additive or synergistic in 85%. CZA combined with colistin, amikacin, or aztreonam was more effective than monotherapy against XDR P. aeruginosa isolates. A CZA combination could be useful for treating XDR P. aeruginosa infections, including those caused by CZA-resistant isolates. IMPORTANCE The emergence of resistance to antibiotics is a serious public health problem worldwide and can be a cause of mortality. For this reason, antibiotic treatment is compromised, and we have few therapeutic options to treat infections. The main goal of our study is to search for new treatment options for infections caused by difficult-to-treat resistant germs. Pseudomonas aeruginosa is a Gram-negative bacterium distributed throughout the world with the ability to become resistant to most available antibiotics. Ceftazidime-avibactam (CZA) emerged as a promising solution to the lack of new antibiotics against infections caused by P. aeruginosa strains. This study intended to analyze the effect of CZA alone or in combination with other available antibiotics against P. aeruginosa strains. The combination of CZA with other antibiotics could be more effective than monotherapy against extensively drug-resistant P. aeruginosa strains.

43 p.-8 fig.-2 tab., Alzheimer's disease (AD), the leading cause of dementia in the elderly, is a neurodegenerative disorder marked by progressive impairment of cognitive ability. Patients with AD display neuropathological lesions including senile plaques, neurofibrillary tangles, and neuronal loss. There are no disease-modifying drugs currently available. With the number of affected individuals increasing dramatically throughout the world, there is obvious urgent need for effective treatment strategy for AD. The multifactorial nature of AD encouraged the development of multifunctional compounds, able to interact with several putative targets. Here, we have evaluated the effects of two in-house designed cannabinoid receptors (CB) agonists showing inhibitory actions on β-secretase-1 (BACE-1) (NP137) and BACE-1/butyrylcholinesterase (BuChE) (NP148), on cellular models of AD, including immortalized lymphocytes from late-onset AD patients. Furthermore, the performance of TgAPP mice in a spatial navigation task was investigated following chronic administration of NP137 and NP148. We report here that NP137 and NP148 showed neuroprotective effects in amyloid-β-treated primary cortical neurons, and NP137 in particular rescued the cognitive deficit of TgAPP mice. The latter compound was able to blunt the abnormal cell response to serum addition or withdrawal of lymphoblasts derived from AD patients. It is suggested that NP137 could be a good drug candidate for future treatment of AD., This work has been supported by grants from Ministerio de Economía y Competitividad (CTQ2015-66313-R, and RTI2018-096100-B-I00) and CIBERNED to MLC.

13 p.-7 fig.-5 tab.-1 graph. abst., A previous phenotypic screening campaign led to the identification of a quinazoline derivative with promising in vitro activity against Schistosoma mansoni. Follow-up studies of the antischistosomal potential of this candidate are presented here. The in vivo studies in a S. mansoni mouse model show a significant reduction of total worms and a complete disappearance of immature eggs when administered concomitantly with praziquantel in comparison with the administration of praziquantel alone. This fact is of utmost importance because eggs are responsible for the pathology and transmission of the disease. Subsequently, the chemical optimisation of the structure in order to improve the metabolic stability of the parent compound was carried out leading to derivatives with improved drug-like properties. Additionally, the putative target of this new class of antischistosomal compounds was envisaged by using computational tools and the binding mode to the target enzyme, aldose reductase, was proposed., This study received funding from the EC 7th Framework Programme (FP7-HEALTH-2013-INNOVATION-1, PDE4NPD no.602666), RICET (RD16/0027/0010), FEDER funds and MECD [Grant FPU15/1465 to V. S.-P.].

BACKGROUND: Limited data regarding altered linezolid pharmacokinetics in patients with liver cirrhosis are available. The objective of this study was to evaluate the pharmacokinetics, efficacy and safety of linezolid in cirrhotic patients. METHODS: A case-control 1:1 study of patients undergoing linezolid therapeutic drug monitoring was conducted between January 2015 and June 2017. Cases with liver cirrhosis were matched with controls by age, body weight, comorbidities, renal function, and intensive care unit (ICU) admission. RESULTS: Fifty-two patients were included, 26 in each group. Patients with Child-Pugh Scores A, B, and C were 1 (3.8%), 13 (50.0%), and 12 (46.2%), respectively. Cases had higher median linezolid trough plasma concentrations than controls [20.6 (17.4) versus 2.7 (11.3); P < 0.001)] and more frequently achieved an optimal pharmacodynamic index [26 (100%) versus 16 (61.5%); P = 0.002]. In addition, potentially toxic concentrations and treatment discontinuation due to overexposure and hematological toxicity were also more frequently seen in cirrhotic patients. Overall clinical cure rate was high (67.4%), and in-hospital mortality was 28.8%. No differences in clinical outcomes were observed between both groups. CONCLUSIONS: Linezolid showed a high clinical cure rate. Nevertheless, plasma concentrations and treatment discontinuation due to hematological toxicity were higher in cirrhotic patients. Liver cirrhosis may influence linezolid pharmacokinetics and question the use of standard doses. Therapeutic drug monitoring of linezolid would be valuable in these patients.

Infectious diseases caused by intestinal protozoan, such as Entamoeba histolytica (E. histolytica) and Giardia lamblia (G. lamblia) are a worldwide public health issue. They affect more than 70 million people every year. They colonize intestines causing primarily diarrhea; nevertheless, these infections can lead to more serious complications. The treatment of choice, metronidazole, is in doubt due to adverse effects and resistance. Therefore, there is a need for new compounds against these parasites. In this work, a structure-based virtual screening of FDA-approved drugs was performed to identify compounds with antiprotozoal activity. The glycolytic enzyme triosephosphate isomerase, present in both E. histolytica and G. lamblia, was used as the drug target. The compounds with the best average docking score on both structures were selected for the in vitro evaluation. Three compounds, chlorhexidine, tolcapone, and imatinib, were capable of inhibit growth on G. lamblia trophozoites (0.05–4.935 μg/mL), while folic acid showed activity against E. histolytica (0.186 μg/mL) and G. lamblia (5.342 μg/mL).

19 p.-5 fig.-1 graph. abst., The introduction of a new drug to the commercial market follows a complex and long process that typically spans over several years and entails large monetary costs due to a high attrition rate. Because of this, there is an urgent need to improve this process using innovative technologies such as artificial intelligence (AI). Different AI tools are being applied to support all four steps of the drug development process (basic research for drug discovery; pre-clinical phase; clinical phase; and postmarketing). Some of the main tasks where AI has proven useful include identifying molecular targets, searching for hit and lead compounds, synthesising drug-like compounds and predicting ADME-Tox. This review, on the one hand, brings in a mathematical vision of some of the key AI methods used in drug development closer to medicinal chemists and, on the other hand, brings the drug development process and the use of different models closer to mathematicians. Emphasis is placed on two aspects not mentioned in similar surveys, namely, Bayesian approaches and their applications to molecular modelling and the eventual final use of the methods to actually support decisions., This work was supported by and supported through the Spanish Ministry of Science and Innovation (RTI2018-096100-B-I00); MTM2017-86875-C3-1-R AEI/FEDER,UE; AXA -ICMAT Chair on Adversarial Risk Analysis; Adversarial Machine Learning: Methods, Computations and Applications to Malware, Fake News and Autonomous Vehicles– Ayudas Fundación BBVA a Equipos de Investigación Científca 2019. AItenea Biotech wants to thank Madrid Emprende for the Madrid Impacta 2020 award.

10 p.-4 fig., Niemann-Pick type C1 (NPC1) receptor is an endosomal membrane protein that regulates intracellular cholesterol traffic. This protein has been shown to play an important role for several viruses. It has been reported that SARS-CoV-2 enters the cell through plasma membrane fusion and/or endosomal entry upon availability of proteases. However, the whole process is not fully understood yet and additional viral/host factors might be required for viral fusion and subsequent viral replication. Here, we report a novel interaction between the SARS-CoV-2 nucleoprotein (N) and the cholesterol transporter NPC1. Furthermore, we have found that some compounds reported to interact with NPC1, carbazole SC816 and sulfides SC198 and SC073, were able to reduce SARS-CoV-2 viral infection with a good selectivity index in human cell infection models. These findings suggest the importance of NPC1 for SARS-CoV-2 viral infection and a new possible potential therapeutic target to fight against COVID-19., This research was partially supported through “La Caixa” Banking Foundation (LCF/PR/HR19/52160012), Instituto de Salud Carlos III (ISCIII–COV20/01007), the Spanish Ministry of Science and Innovation (RTI2018-097305-R-I00), CSIC (PIE-RD-COVID-19 refs. E201980E024 and E202020E079) and the European Union-NextGenerationEU. EVA (European Virus Archive; grant agreement No 871029).

Niemann-Pick type C1 (NPC1) receptor is an endosomal membrane protein that regulates intracellular cholesterol trafficking, which is crucial in the Ebola virus (EBOV) cycle. The severe acute respiratory syndrome coronavirus 2 (SARS- CoV-2) enters the cell by binding of the viral spike (S) protein to the ACE2 receptor. This requires S-protein processing either by the surface transmembrane serine protease TMPRSS2 for plasma membrane fusion or cathepsin L for endosomal entry. Additional host factors are required for viral fusion at endosomes. Here, we report a novel interaction of the SARS-CoV-2 nucleoprotein (N) with the cholesterol transporter NPC1. Moreover, small molecules interfering with NPC1 that inhibit EBOV entry, also inhibited human coronavirus. Our findings suggest an important role for NPC1 in SARS-CoV-2 infection, a common strategy shared with EBOV, and a potential therapeutic target to fight against COVID-19., This research was partially supported through “La Caixa” Banking Foundation (HR18-00469), Instituto de Salud Carlos III (ISCIII-COV20/01007), CSIC (201980E024 and 202020E079), Spanish Ministry of Science and Innovation (RTI2018-097305-R-I00) and the European Commission Horizon 2020 Framework Programme VACDIVA-SFS482 12-2019-1-862874.

Synthesis and pharmacological evaluation of a new series of cannabinoid receptor antagonists of indazole ether derivatives have been performed. Pharmacological evaluation includes radioligand binding assays with [H]-CP55940 for CB1 and CB2 receptors and functional activity for cannabinoid receptors on isolated tissue. In addition, functional activity of the two synthetic cannabinoids antagonists 18 (PGN36) and 17 (PGN38) were carried out in the osteoblastic cell line MC3T3-E1 that is able to express CB2R upon osteogenic conditions. Both antagonists abolished the increase in collagen type I gene expression by the well-known inducer of bone activity, the HU308 agonist. The results of pharmacological tests have revealed that four of these derivatives behave as CB2R cannabinoid antagonists. In particular, the compounds 17 (PGN38) and 18 (PGN36) highlight as promising candidates as pharmacological tools., This work was supported from Ministerio de Ciencia e Innovación under Grant RTI2018-096100B-100, Plan Nacional de I + D + I 2013-2016, ISCIII–FEDER (FIS16/00637), Plan de Ciencia, Tecnología e Innovación 2013-2017 and 2018-2022 del Principado de Asturias (GRUPIN14-028, IDI-2018-000152), RedInRen from ISCIII (RD16/0009/0017). Natalia Carrillo López was supported by GRUPIN14-028 and IDI-2018-000152.

Combination therapy is an attractive therapeutic option for extensively drug-resistant (XDR) Pseudomonas aeruginosa infections. Colistin has been the only treatment available for these infections for many years, but its results are suboptimal. Ceftolozane-tazobactam (C/T) is a newly available therapeutic option that has shown good antipseudomonal activity, even against a number of XDR P. aeruginosa strains. However, data about combinations containing C/T are scarce. The aim of this study was to analyze the activity of C/T and colistin alone and in combination against a collection of XDR P. aeruginosa strains containing 24 representative clinical isolates from a multicentre Spanish study. Twenty-four time-kill experiments performed over 24 h were conducted in duplicate to determine the effects of colistin and C/T alone and combined. An in vitro pharmacodynamic chemostat model then was used to validate this combination against three selected XDR P. aeruginosa ST175 isolates with different susceptibility levels to C/T. Static time-kill assays demonstrated superior synergistic or additive effect for C/T plus colistin against 21 of the 24 isolates studied. In the in vitro dynamic pharmacokinetic/pharmacodynamic (PK/PD) model, the C/T regimen of 2/1 g every 8 h with a steady-state concentration of 2 mg/liter colistin effectively suppressed the bacterial growth at 24 h. Additive or synergistic interactions were observed for C/T plus colistin against XDR P. aeruginosa strains and particularly against C/T-resistant strains. C/T plus colistin may be a useful treatment for XDR P. aeruginosa infections, including those caused by high risk-clones resistant to C/T.

More than 1 billion people live in areas endemic for leishmaniasis, which is a relevant threat for public health worldwide. Due to the inadequate treatments, there is an urgent need to develop novel alternative drugs and to validate new targets to fight this disease. One appealing approach is the selective inhibition of protein kinases (PKs), enzymes involved in a wide range of processes along the life cycle of Leishmania. Several PKs, including glycogen synthase kinase 3 (GSK-3), have been validated as essential for this parasite by genetic or pharmacological methods. Recently, novel chemical scaffolds have been uncovered as Leishmania GSK-3 inhibitors with antiparasitic activity. In order to find new inhibitors of this enzyme, a virtual screening of our in-house chemical library was carried out on the structure of the Leishmania GSK-3. The virtual hits identified were experimentally assayed both for leishmanicidal activity and for in vitro inhibition of the enzyme. The best hits have a quinone scaffold. Their optimization through a medicinal chemistry approach led to a set of new compounds, provided a frame to establish biochemical and antiparasitic structure–activity relationships, and delivered molecules with an improved selectivity index. Altogether, this study paves the way for a systemic search of this class of inhibitors for further development as potential leishmanicidal drugs., Funding from MINECO (Grant SAF2015-65740-R), Instituto de Salud Carlos III RETICS programme RICET (RD16/0027/0010) with associated FEDER funds and MECD (Grant FPU15/1465 to V.S.-P.) is acknowledged. P.M.I. acknowledges the contract from the European Social Fund (Youth Employment Initiative) and FEDER funds of the Autonomous Government of Madrid

12 p.-5 fig.-2 tab.-1 graph. abst., Niemann-Pick C1 (NPC1) receptor is an intracellular protein located in late endosomes and lysosomes whose main function is to regulate intracellular cholesterol trafficking. Besides being postulated as necessary for the infection of highly pathogenic viruses in which the integrity of cholesterol transport is required, this protein also allows the entry of the Ebola virus (EBOV) into the host cells acting as an intracellular receptor. EBOV glycoprotein (EBOV-GP) interaction with NPC1 at the endosomal membrane triggers the release of the viral material into the host cell, starting the infective cycle. Disruption of the NPC1/EBOV-GP interaction could represent an attractive strategy for the development of drugs aimed at inhibiting viral entry and thus infection. Some of the today available EBOV inhibitors were proposed to interrupt this interaction, but molecular and structural details about their mode of action are still preliminary thus more efforts are needed to properly address these points. Here, we provide a critical discussion of the potential of NPC1 and its interaction with EBOV-GP as a therapeutic target for viral infections., The project leading to these results has received funding from “la Caixa” Banking Foundation under the project code LCF/PR/HR19/52160012. This research was partially supported through the Spanish Ministry of Science and Innovation (RTI2018-097305-R-I00), the Instituto de Investigación Carlos III, ISCIII, (FIS PI 1801007) and the European Commission Horizon 2020 Framework Programme Project VIRUSCAN FETPROACT-2016: 731868. M. M. holds a pre-doctoral FPU grant (FPU18/03493) from MICINN.

68 p.-17 fig.-1 tab. Chierrito, Talita P. C. et al., The lack of an effective treatment for Alzheimer' disease (AD), an increasing prevalence and severe neurodegenerative pathology boost medicinal chemists to look for new drugs. Currently, only acethylcholinesterase (AChE) inhibitors and glutamate antagonist have been approved to the palliative treatment of AD. Although they have a short-term symptomatic benefits, their clinical use have revealed important non-cholinergic functions for AChE such its chaperone role in beta-amyloid toxicity. We propose here the design, synthesis and evaluation of non-toxic dual binding site AChEIs by hybridization of indanone and quinoline heterocyclic scaffolds. Unexpectely, we have found a potent allosteric modulator of AChE able to target cholinergic and non-cholinergic functions by fixing a specific AChE conformation, confirmed by STD-NMR and molecular modeling studies. Furthermore the promising biological data obtained on human neuroblastoma SH-SY5Y cell assays for the new allosteric hybrid 14, led us to propose it as a valuable pharmacological tool for the study of non-cholinergic functions of AChE, and as a new important lead for novel disease modifying agents against AD., Financial support of this research provided by the Fundação de Pesquisa e Amparo do Estado de São Paulo-FAPESP (Proc. 12/04054-5; 12/14114-5; 13/50788-3; 14-10414-0); Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES), CSIC (grant no. i-LINK-0801) and MINECO (grants no. SAF2016-76693-R to A.M., and CTQ2015-64597-C2-1 to J.J.B. and F.J.C.) is acknowledged

A new family of imidazo[4,5-c][1,2,6]thiadiazine 2,2-dioxide with antiproliferative Trypanosoma cruzi properties was identified from a neural network model published by our group. The synthesis and evaluation of this new class of trypanocidal agents are described. These compounds inhibit the growth of Trypanosoma cruzi, comparable with benznidazole or nifurtimox. In vitro assays were performed to study their effects on the growth of the epimastigote form of the Tulahuen 2 strain, as well as the epimastigote and amastigote forms of CL clone B5 of Trypanosoma cruzi. To verify selectivity towards parasite cells, the non-specific cytotoxicity of the most relevant compounds was studied in mammalian cells, i.e. J774 murine macrophages and NCTC clone 929 fibroblasts. Furthermore, these compounds were assayed regarding the inhibition of cruzipain. In vivo studies revealed that one of the compounds, 19, showed interesting trypanocidal activity, and could be a very promising candidate for the treatment of Chagas disease.

22 p.-5 fig., Introduction: Glycogen synthase kinase 3 (GSK-3) was identified in the late 1970s and is a constitutively active, ubiquitous expressed serine/threonine kinase that is involved in a large number of signaling pathway such as insulin, Wnt, Reelin, Notch, Hedgehog signaling, among others. GSK-3 is a key target of a remarkably large number of cellular processes and diseases such as diabetes type II, bipolar disorder, chronic inflammatory disease, cancer, immune disorder, neurodegenerative pathologies among others diseases and surely in regenerative medicine. During the last decades the scientific community has been working trying to understand the role of GSK-3 different disorders with the aim in mind of design efficient and selectivity GSK-3 inhibitors. However so far clinical and preclinical GSK-3 inhibitors have been both sub-optimal regarding potency, poor GSK-3 selectivity over other CNS targets and closely related kinases, low CNS exposure and chronic toxicity. Research into GSK inhibitors relay primarily on identification of the new use of the know GSK-3 inhibitors and the development of them in order to improve selectivity and toxicity., Areas covered: This review covers patent literature on GSK-3 inhibitors and their application published between 2016-2019., Expert opinion: Thanks to the past, present and future research, in the next few years we will see progress in the treatment of some diseases with GSK-3 inhibitors, for instance in regenerative medicine immunotherapy applications among others., This work was supported by the Ministerio de Ciencia e Innovación under Grant RTI2018-096100B-100.

Objectives To assess the pharmacokinetics of formed colistin in plasma and the safety of two different high doses of colistimethate sodium administered via nebulization in critically ill surgical patients with hospital-acquired pneumonia (HAP) or ventilator-associated pneumonia (VAP). Patients and methods Formed colistin plasma concentrations were measured in critically ill surgical patients with pneumonia treated with two different doses of nebulized colistimethate sodium (3 MIU/8 h versus 5 MIU/8 h). Adverse events possibly related to nebulized colistimethate sodium were recorded. Results Twenty-seven patients (15 in the 3 MIU/8 h group and 12 in the 5 MIU/8 h group) were included. Colistin plasma concentrations were unquantifiable ( Conclusions In this limited observational case series of critically ill patients with HAP or VAP treated with high doses of nebulized colistimethate sodium, systemic exposure was minimal and the treatment was well tolerated.

Although hematopoietic and immune system show high levels of the cannabinoid receptor CB2, the potential effect of cannabinoids on hematologic malignancies has been poorly determined. Here we have investigated their anti-tumor effect in multiple myeloma (MM). We demonstrate that cannabinoids induce a selective apoptosis in MM cell lines and in primary plasma cells of MM patients, while sparing normal cells from healthy donors, including hematopoietic stem cells. This effect was mediated by caspase activation, mainly caspase-2, and was partially prevented by a pan-caspase inhibitor. Their pro-apoptotic effect was correlated with an increased expression of Bax and Bak, a decrease of Bcl-xL and Mcl-1, a biphasic response of Akt/PKB and an increase in the levels of ceramide in MM cells. Inhibition of ceramide synthesis partially prevented apoptosis, indicating that these sphingolipids play a key role in the pro-apoptotic effect of cannabinoids in MM cells. Remarkably, blockage of the CB2 receptor also inhibited cannabinoid-induced apoptosis. Cannabinoid derivative WIN-55 enhanced the anti-myeloma activity of dexamethasone and melphalan overcoming resistance to melphalan in vitro. Finally, administration of cannabinoid WIN-55 to plasmacytoma-bearing mice significantly suppressed tumor growth in vivo. Together, our data suggest that cannabinoids may be considered as potential therapeutic agents in the treatment of MM.

Summary Objectives Optimal dosage regimens of colistin for the treatment of urinary tract infections (UTI) are unknown. Colistimethate sodium (CMS), the inactive prodrug of colistin, is mainly excreted in urine and converts to colistin after filtration by glomeruli, suggesting that concentrations of colistin in urine could be much higher than in plasma. Therefore, there is a need to optimize dosage regimens of intravenous CMS for UTI. The aim of this study was to examine the relationship between AUC/MIC of formed colistin and clinical outcomes in patients with UTI caused by extremely drug resistant (XDR) Pseudomonas aeruginosa. Methods This prospective, observational cohort study involved patients with UTI caused by XDR P. aeruginosa. Clinical cure, bacteriological clearance and acute kidney injury (AKI) were analyzed. Steady-state colistin plasma concentrations (Css) were measured using HPLC. Based on the PK/PD of colistin in neutropenic mouse thigh infection models with P. aeruginosa, the optimal AUC/MIC should be ≥60 mg·h/L. According to the pharmacokinetics (PK) in critically-ill patients, the Css target of formed colistin in plasma was 2.5 mg/L. Results Thirty-three patients were included (24 lower UTI and 9 pyelonephritis). The MIC50 and MIC90 values for colistin were 0.5 and 2 mg/L respectively. Nineteen patients (57.6%) received colistin monotherapy (84.2% lower UTI and 15.8% pyelonephritis). Of these, clinical cure was achieved in 89.5% of cases. Among patients with clinical cure and monotherapy, only 5 (29.4%) attained an optimal plasma AUC/MIC and only 1 (5.9%) the therapeutic level of formed colistin (2.5 mg/L). However, 10 (58.8%) patients showed colistin plasma concentrations above the MIC of the isolated P. aeruginosa. Microbiological eradication was achieved in 76.9% of patients. AKI at the end of treatment was present in 29.4% of patients. Conclusions The currently recommended dosage regimens of CMS showed high efficacy for the treatment of lower complicated UTI caused by XDR P. aeruginosa in non-critically ill patients and in the case of low MIC values, but also a considerable nephrotoxicity rate. Our data suggest that the use of lower CMS doses for lower UTI should be investigated in future studies to minimize the unnecessary nephrotoxicity.

Background: Extensively drug-resistant (XDR) Pseudomonas aeruginosa (P. aeruginosa) and particularly P. aeruginosa high-risk clones, are of growing concern because treatment options are limited. For years, colistin monotherapy has been the only available treatment, but is well known that is not an optimal treatment. A combination of colistin with another antibiotic could be a possible therapeutic option. Objectives: This study aimed to investigate effective antibiotic combinations against 20 XDR P. aeruginosa isolates obtained in a Spanish multicentre study (2015). Methods: Forty-five checkerboards with six antipseudomonal antibiotics (amikacin, aztreonam, ceftazidime, meropenem, colistin, and ceftolozane/tazobactam) were performed to determine whether combinations were synergic or additive by fractional inhibitory concentration indices. On average, 15 different regimens were evaluated in duplicate against the three most prevalent high-risk clones (ST175, ST235, ST111) by time-kill analyses over 24 h. The combination showing synergism in the three high-risk clones was validated in all studied XDR isolates. Results: In time-kill curves, the untreated control failed, as did each study regimen when administered alone. Two combinations were synergistic in the three high-risk clones that were initially studied: amikacin plus ceftazidime and colistin plus meropenem, with the second being the most effective combination. The efficacy of colistin plus meropenem was then tested in all 20 isolates. A synergistic bacterial density reduction for the duration of the study occurred in 80% of the entire XDR collection. Conclusions: These data suggest that colistin plus meropenem may be a useful combination for the treatment of infections due to XDR P. aeruginosa, including high-risk clones, which warrants evaluation in a clinical trial. (C) 2019 International Society for Antimicrobial Chemotherapy. Published by Elsevier Ltd. All rights reserved.

13 p.-6 fig.-5 tab., Alzheimer's disease is one of the most common neurodegenerative disorders in elder population. The β-site amyloid cleavage enzyme 1 (BACE1) is the major constituent of amyloid plaques and plays a central role in this brain pathogenesis, thus it constitutes an auspicious pharmacological target for its treatment. In this paper, a QSAR model for identification of potential inhibitors of BACE1 protein is designed by using classification methods. For building this model, a database with 215 molecules collected from different sources has been assembled. This dataset contains diverse compounds with different scaffolds and physical-chemical properties, covering a wide chemical space in the drug-like range. The most distinctive aspect of the applied QSAR strategy is the combination of hybridization with backward elimination of models, which contributes to improve the quality of the final QSAR model. Another relevant step is the visual analysis of the molecular descriptors that allows guaranteeing the absence of information redundancy in the model. The QSAR model performances have been assessed by traditional metrics, and the final proposed model has low cardinality, and reaches a high percentage of chemical compounds correctly classified., This work is kindly supported by CONICET, grant PIP 112–2012–0100471, by UNS, grants PGI 24/N042 and PGI 24/ZM17, Ministerio de Economía y Competitividad (CTQ2015-66313-R) and by MINCYT, for their economic support given to IP in the “6° Programa de Movilidad Docente a Madrid”.

13 p.-5 fig.-2 tab.-1 graph.abs + supp.inf. 38 p.-2 fig.supl.-5 tab. supl., Previous reports have validated the glycogen synthase kinase-3 (GSK-3) as a druggable target against the human protozoan parasite Leishmania. This prompted us to search for new leishmanicidal scaffolds as inhibitors of this enzyme from our in-house library of human GSK-3β inhibitors, as well as from the Leishbox collection of leishmanicidal compounds developed by GlaxoSmithKline. As a result, new leishmanicidal inhibitors acting on Leishmania GSK-3 at micromolar concentrations were found. These inhibitors belong to six different chemical classes (thiadiazolidindione, halomethylketone, maleimide, benzoimidazole, N-phenylpyrimidine-2-amine and oxadiazole). In addition, the binding mode of the most active compounds into Leishmania GSK-3 was approached using computational tools. On the whole, we have uncovered new chemical scaffolds with an appealing prospective in the development and use of Leishmania GSK-3 inhibitors against this infectious protozoan., Funding from MINECO [Grant SAF2015-65740-R], Instituto de Salud Carlos III RETICS programme RICET [RD16/0027/0010] with associated FEDER funds and MECD [Grant FPU15/1465 to V. S.-P.] is acknowledged. P. M. acknowledges the contract from the European Social Fund (Youth Employment Initiative) and FEDER funds.

Multitarget cannabinoids could be a promising therapeutic strategic to fight against Alzheimer's disease. In this sense, our group has developed a new family of indazolylketones with multitarget profile including cannabinoids, cholinesterase and BACE-1 activity. A medicinal chemistry program that includes computational design, synthesis and in vitro and cellular evaluation has allowed to us to achieve lead compounds. In this work, the synthesis and evaluation of a new class of indazolylketones have been performed. Pharmacological evaluation includes functional activity for cannabinoid receptors on isolated tissue. In addition, in vitro inhibitory assays in AChE/BuChE enzymes and BACE-1 have been carried out. Furthermore, studies of neuroprotective effects in human neuroblastoma SH-SY5Y cells and studies of the mechanisms of survival/death in lymphoblasts of patients with Alzheimer's disease have been achieved. The results of pharmacological tests have revealed that some of these derivatives (5, 6) behave as CB2 cannabinoid agonists and simultaneously show BuChE and/or BACE-1 inhibition., The authors gratefully acknowledge the financial support of Ministerio Español de Economía y Competitividad (CTQ2015- 66313-R) and would like to thank to Guadalupe Pablo and Carmen Merino for their excellent technical assistant. The work of MLC was supported by the Centre for Biomedical Research on Neurodegenerative Diseases (CIBERNED). GV was supported by a fellowship from SENECYT (Ecuador). Work dedicated in memoriam to Mercedes González Hormaizteguy, a great women scientist and wonderful person

11 p.-9 fig.-3 tab., Numerous studies have highlighted the implications of the glycogen synthase kinase 3 (GSK-3) in several processes associated with Alzheimer's disease (AD). Therefore, GSK-3 has become a crucial therapeutic target for the treatment of this neurodegenerative disorder. Hereby, we report the design and multistep synthesis of ethyl 4-oxo-pyrazolo[4,3-d][1-3]triazine-7-carboxylates and their biological evaluation as GSK-3 inhibitors. Molecular modelling studies allow us to develop this new scaffold optimising the chemical structure. Potential binding mode determination in the enzyme and the analysis of the key features in the catalytic site are also described. Furthermore, the ability of pyrazolotriazinones to cross the blood-brain barrier (BBB) was evaluated by passive diffusion and those who showed great GSK-3 inhibition and permeation to the central nervous system (CNS) showed neuroprotective properties against tau hyperphosphorylation in a cell-based model. These new brain permeable pyrazolotriazinones may be used for key in vivo studies and may be considered as new leads for further optimisation for the treatment of AD., Funding from MINECO (grant no. SAF2016-76693-R to A.M.) and MEC (FPU15/1465 to VSP.), CONICET and SECYT-UNC are also acknowledged.

Several findings propose the altered tau protein network as an important target for Alzheimer's disease (AD). Particularly, two points of pharmacological intervention can be envisaged: inhibition of phosphorylating tau kinase GSK-3β and tau aggregation process. On the basis of this consideration and on our interest in multitarget paradigms in AD, we report on the discovery of 2,4-thiazolidinedione derivatives endowed with such a profile. 28 and 30 displayed micromolar IC values toward GSK-3β, together with the capacity of inhibiting AcPHF6 aggregation of 60% and 80% at 10 μM, respectively. In addition, they showed PAMPA-BBB permeability, together with a suitable cellular safety profile. 30 also displayed inhibition of both K18 and full-length tau aggregations. Finally, both compounds were able to improve cell viability in an okadaic acid-induced neurodegeneration cell model. To the best of our knowledge, 28 and 30 are the first balanced, nontoxic, dual-acting compounds hitting tau cascade at two different hubs., This work was supported by the University of Bologna (RFO2015_2016), European Cooperation of Science and Technology (EUCOST) Action CA15135, Ministerio de Economia y Competitividad (CTQ2015-66313-R), Italian Ministry of Health (GR-2013-02355724), MJFF, ALZ, Alzheimer’s Research UK and the Weston Brain Institute (BAND2015). The authors thank E. De Cecco (PhD candidate, SISSA) for providing K18 and 2N4R protein samples for the in vitro assays.

43 p.-6 fig.-3 tab. BACKGROUND:Alzheimer's disease is a multifactorial disorder for which there is no disease-modifying treatment yet. CB2 receptors have emerged as a promising therapeutic target for Alzheimer's disease because they are expressed in neuronal and glial cells and their activation has no psychoactive effects. OBJECTIVE:The aim of this study was to investigate whether activation of the CB2 receptor would restore the aberrant enhanced proliferative activity characteristic of immortalized lymphocytes from patients with late-onset Alzheimer's disease. It is assumed that cell-cycle dysfunction occurs in both peripheral cells and neurons in patients with Alzheimer's disease, contributing to the instigation of the disease. METHODS:Lymphoblastoid cell lines from patients with Alzheimer's disease and age-matched control individuals were treated with a new, in-house-designed dual drug PGN33, which behaves as a CB2 agonist and butyrylcholinesterase inhibitor. We analyzed the effects of this compound on the rate of cell proliferation and levels of key regulatory proteins. In addition, we investigated the potential neuroprotective action of PGN33 in β-amyloid-treated neuronal cells. RESULTS:We report here that PGN33 normalized the increased proliferative activity of Alzheimer's disease lymphoblasts. The compound blunted the calmodulin-dependent overactivation of the PI3K/Akt pathway, by restoring the cyclin-dependent kinase inhibitor p27 levels, which in turn reduced the activity of the cyclin-dependent kinase/pRb cascade. Moreover, this CB2 agonist prevented β-amyloid-induced cell death in neuronal cells. CONCLUSION:Our results suggest that the activation of CB2 receptors could be considered a useful therapeutic approach for Alzheimer's disease. This work has been supported by a Grant from Ministerio de Economía y Competitividad (CTQ2015-66313-R). FB is supported by a Sara Borrell fellowship from the Spanish Instituto de Salud Carlos III.

Dementia is one of the main causes of the disease burden in developed regions. According to the World Health Organization (WHO), it will become the world's second leading cause of death by the middle of the century, overtaking cancer. This will have a dramatic impact on medical care, and have important social and economic implications, unless more effective preventive procedures or treatments become available. Alzheimer's disease (AD) is the most common cause of dementia, accounting for approximately 50-75% of all dementias worldwide, followed by vascular dementia, mixed dementia, and Lewy body dementia. Currently, acetylcholinesterase (AChE) inhibitors, such as donepezil, rivastigmine and galantamine are used to treat mild to moderate AD. An alternative therapy for severe AD is memantine, an antagonist of the NMDA-subtype of glutamate receptors. However, these drugs provide only temporary symptom improvement, and do not alter disease progression, except temporarily in some patients. In recent years different approaches have been developed to provide a more effective treatment for AD. These approached include the discovery of emerging targets and new drugs aiming at a single target, but given the complexity of the disease, different targets may need to be engaged simultaneously. New strategies have explored bitopic inhibitors, for example a single drug that acts on different sites of the acetylcholinesterase enzyme to produce at least two different activities, and multitarget drugs that act on multiple therapeutic targets. In this review, we explore the journey from a bitopic inhibitor strategy to multitarget drugs for the future treatment of AD.

Fragile X syndrome (FXS) is a common form of mental disability characterized by hypersensitivity to sensory stimuli, hyperactivity and severe cognitive impairment. FXS is caused by loss of the fragile X mental retardation 1 ( FMR1 ) gene, whose fragile X mental retardation protein (FMRP) regulates mRNA translation downstream of synaptic activity to modulate changes in synaptic architecture, function and plasticity. FXS is one of the known causes of autism and there is no effective treatment that corrects the deficit in FMRP. However, new advances in the knowledge of the molecular pathophysiology of FXS have opened different strategies for the future development of effective drugs. Among the emerging targets are several protein kinases, neuronal calcium sensors, muscarinic receptors, potassium channels, endocannabinoid system, etc. Moreover, some small molecules such statins, antioxidants, glycogen synthase kinase 3 inhibitors among others have showed an improved in cognition and behavioral tests in FXS mouse model emerging as promising drug candidates for FXS pharmacological treatment in the next future.

Nephrotoxicity limits the effective use of colistin for the treatment of multidrug-resistant Gram-negative bacteria (MDR-GNB) infections. We previously defined a steady-state colistin plasma concentration (C-ss) of 2.42 mg/L that predicted nephrotoxicity at end of treatment (EOT). The objective of this study was to validate this breakpoint in a prospective cohort. This was a multicentre, prospective, observational study conducted at three hospitals with a cohort of patients treated for MDR-GNB infection with colistin methanesulfonate from September 2011 until January 2015. Nephrotoxicity was evaluated at Day 7 and at EOT using the RIFLE criteria. C-ss values were measured and analysed using HPLC. Taking the previously defined breakpoint for colistin concentration as a criterion, patients were divided into two groups (C-ss, 2.42 mg/L). Sixty-four patients were included. Seven patients (10.9%) had a C-ss > 2.42 mg/L and were compared with the remaining patients. Bivariate analysis showed that patients with a C-ss > 2.42 mg/L were older and had a significantly higher incidence of nephrotoxicity at Day 7 and EOT. Although not statistically significant, nephrotoxicity occurred earlier in these patients (6.2 days vs. 9.2 days in patients with lower C-ss; P = 0.091). Multivariate analysis of nephrotoxicity showed that C-ss > 2.42 mg/L was the only predictive factor. Nephrotoxicity was more frequent and occurred earlier in patients with colistin plasma concentrations higher than the previously defined breakpoint (2.42 mg/L). Colistin therapeutic drug monitoring should be routinely considered to avoid reaching this toxicity threshold and potential clinical consequences. (C) 2016 Elsevier B.V. and International Society of Chemotherapy. All rights reserved.

15 p.-10 fig.-5 tab., Allosteric sites on proteins are targeted for designing more selective inhibitors of enzyme activity and to discover new functions. Acetylcholinesterase (AChE), which is most widely known for the hydrolysis of the neurotransmitter acetylcholine, has a peripheral allosteric subsite responsible for amyloidosis in Alzheimer's disease through interaction with amyloid β-peptide. However, AChE plays other non-hydrolytic functions. Here, we identify and characterise using computational tools two new allosteric sites in AChE, which have allowed us to identify allosteric inhibitors by virtual screening guided by structure-based and fragment hotspot strategies. The identified compounds were also screened for in vitro inhibition of AChE and three were observed to be active. Further experimental (kinetic) and computational (molecular dynamics) studies have been performed to verify the allosteric activity. These new compounds may be valuable pharmacological tools in the study of non-cholinergic functions of AChE., We thank to Ministerio de Educación, Cultura y Deporte (Grant of V.S.P, FPU15/01465 and Grant of N.E.C., Programa “Salvador de Madariaga” PR2015–00476).

Alzheimer's disease (AD) is the most common form of dementia worldwide with an increasing prevalence for the next years. The multifactorial nature of AD precludes the design of new drugs directed to a single target being probably one of the reasons for recent failures. Therefore, dual binding site acetylcholinesterase (AChE) inhibitors have been revealed as cognitive enhancers and β-amyloid modulators offering an alternative in AD therapy field. Based on the dual ligands NP61 and donepezil, the present study reports the synthesis of a series of indolylpiperidines hybrids to optimize the NP61 structure preserving the indole nucleus, but replacing the tacrine moiety of NP61 by benzyl piperidine core found in donepezil. Surprisingly, this new family of indolylpiperidines derivatives showed very potent and selective hBuChE inhibition. Further studies of NMR and molecular dynamics have showed the capacity of these hybrid molecules to change their bioactive conformation depending on the binding site, being capable to inhibit with different shapes BuChE and residually AChE., Financial support of this research provided by the Fundaç~ao de Pesquisa e Amparo do Estado de S~ao Paulo-FAPESP (Proc.12/04054- 5; 12/14114-5; 13/50788-3; 14/10414-0; 17/04695-4); Coordenaç~ao de Aperfeiçoamento de Pessoal de Nível Superior (CAPES), Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq), CSIC (grant no. i-LINK-0801) and MINECO (grants no. SAF2016-76693-R to A.M., CTQ 2016-76263 to A.C. and CTQ 2015- 64597-C2-2 to F.J.C.) is acknowledged. Authors want to express their gratitude to Prof. G. Pepeu for the experimental work in target engagement.

8 p.-3 fig.-2 tab. 12th International Conference on Practical Applications of Computational Biology and Bioinformatics, PACBB 2018; Toledo; Spain; 20 June 2018 through 22 June 2018; Code 217169, Parkinson’s disease is one of the most common neurodegenerative disorders in elder people and the leucine-rich repeat kinase 2 (LRRK2) is a promising target for its pharmacological treatment. In this paper, QSAR models for identification of potential inhibitors of LRRK2 protein are designed by using an in house chemical library and several machine learning methods. The applied methodology works in two steps: first, several alternative subsets of molecular descriptors relevant for characterizing LRRK2 inhibitors are identified by a feature selection software tool; secondly, QSAR models are inferred by using these subsets and three different methods for supervised learning. The performance of all these QSAR models are assessed by traditional metrics and the best models are analyzed in statistical and physicochemical terms., This work is kindly supported by CONICET, grant PIP 112-2012-0100471 and UNS, grants PGI 24/N042 and PGI 24/ZM17. We also acknowledge MECD, VSP grant FPU15/01465 and Banco Santander for VSP fellowship AY21/17-D-27 in the “Becas Iberoamerica-Santander Investigación” program.

34 p.-9 fig.-1 tab.-1 graph. abst., Acetylcholinesterase (AChE) is the key enzyme targeted in Alzheimer's disease (AD) therapy, nevertheless butyrylcholinesterase (BuChE) has been drawing attention due to its role in the disease progression. Thus, we aimed to synthesize novel cholinesterases inhibitors considering structural differences in their peripheral site, exploiting a moiety replacement approach based on the potent and selective hAChE drug donepezil. Hence, two small series of N-benzylpiperidine based compounds have successfully been synthesized as novel potent and selective hBuChE inhibitors. The most promising compounds (9 and 11) were not cytotoxic and their kinetic study accounted for dual binding site mode of interaction, which is in agreement with further docking and molecular dynamics studies. Therefore, this study demonstrates how our strategy enabled the discovery of novel promising and privileged structures. Remarkably, compound 11 proved to be one of the most potent (0.17 nM) and selective (>58,000-fold) hBuChE inhibitor ever reported., This work was supported by Fundação de Amparo à Pesquisa do Estado de São Paulo – FAPESP (grant 2012/14114-5, 2013/50788-3, 2014/04868-8), Coordenadoria de Aperfeiçoamento de Pessoal de Nível Superior (CAPES), Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Consejo Superior de Investigaciones Científicas – CSIC (grant i-Link0801) and MINECO (CTQ2015-66313-R).

Protein-protein interactions (PPIs) are known to play an essential role between the neuronal calcium sensor 1 (NCS-1) and the guanine exchange factor Ric8a to regulate synapse function, emerging as a druggable interface for synaptopathies such as the fragile X syndrome (FXS). Recently, the phenothiazine FD44 has been identified as an inhibitor of this PPI, decreasing the abnormally high synapse number and enhancing associative learning in a FXS animal model. Here, we have integrated advanced experimental and computational studies to obtain important structural insights into Drosophila NCS-1/FD44 recognition to understand the basis of its affinity and specificity and generate improved PPI regulators. This has allowed the identification of a new small drug-like molecule, IGS-1.76, which efficiently inhibits the human NCS-1/Ric8a complex with improved binding potency. The crystal structure of the Drosophila NCS-1/IGS-1.76 complex demonstrates that the new inhibitor, although chemically different from FD44, shares the same mechanism of action and constitutes a new hit candidate for FXS.

70 p.-18 fig.-3 tab., The discovery of cannabinoid receptors at the beginning of the 1990s, CB1 cloned in 1990 and CB2 cloned in 1993, and the availability of selective and potent cannabimimetics could only be justified by the existence of endogenous ligands that are capable of binding to them. Thus, the characterisation and cloning of the first cannabinoid receptor (CB1) led to the isolation and characterisation of the first endocannabinoid, arachidonoylethanolamide (AEA), two years later and the subsequent identification of a family of lipid transmitters known as the fatty acid ester 2-arachidonoylglycerol (2-AG). The endogenous cannabinoid system is a complex signalling system that comprises transmembrane endocannabinoid receptors, their endogenous ligands (the endocannabinoids), the specific uptake mechanisms and the enzymatic systems related to their biosynthesis and degradation. The endocannabinoid system has been implicated in a wide diversity of biological processes, in both the central and peripheral nervous systems, including memory, learning, neuronal development, stress and emotions, food intake, energy regulation, peripheral metabolism, and the regulation of hormonal balance through the endocrine system. In this context, this article will review the current knowledge of the therapeutic potential of cannabinoid receptor as a target in Alzheimer's disease and other less well-known diseases that include, among others, multiple sclerosis, bone metabolism, and Fragile X syndrome. The therapeutic applications will be addressed through the study of cannabinoid agonists acting as single drugs and multi-target drugs highlighting the CB2 receptor agonist., Financial support from MINECO, Spain (Grant No.CTQ2015-66313-R)., Preprint

Neglected tropical diseases represent a significant health burden in large parts of the world. Drug discovery is currently a key bottleneck in the pipeline of these diseases. In this chapter, the in silico approaches used for the processes involved in drug discovery, identification and validation of druggable Leishmania targets, and design and optimisation of new anti-leishmanial drugs are discussed. We also provide a general view of the different computational tools that can be employed in pursuit of this aim, along with the most interesting cases found in the literature.

Limited information is available on the urinary excretion of colistin in infected patients. This study aimed to investigate the pharmacokinetics of colistimethate sodium (CMS) and formed colistin in urine in patients with multidrug-resistant (MDR) Gram-negative bacterial infections. A pharmacokinetic study was conducted on 12 patients diagnosed with an infection caused by an extremely drug-resistant (XDR) P. aeruginosa strain and treated with intravenous CMS. Fresh urine samples were collected at 2-h intervals, and blood samples were collected predose ( C min ss ) and at the end of the CMS infusion ( C max ss ) for measurement of concentrations of CMS and formed colistin using high-performance liquid chromatography (HPLC). CMS urinary recovery was determined as the summed amount of CMS and formed colistin recovered in urine for each 2-h interval divided by the CMS dose. There were 12 enrolled patients, 9 of whom were male (75%). Data [median (range)] were as follows: age, 65.5 (37 to 86) years; colistimethate urinary recovery 0 to 6 h, 42.6% (2.9% to 72.8%); range of concentrations of colistin in urine, C min ss and C max ss of colistin in plasma, 0.9 (P. aeruginosa in our hospital. Future studies are warranted for optimizing CMS dosage regimens in urinary tract infection (UTI) patients.

The protein complex formed by the Ca2+ sensor neuronal calcium sensor 1 (NCS-1) and the guanine exchange factor protein Ric8a coregulates synapse number and probability of neurotransmitter release, emerging as a potential therapeutic target for diseases affecting synapses, such as fragile X syndrome (FXS), the most common heritable autism disorder. Using crystallographic data and the virtual screening of a chemical library, we identified a set of heterocyclic small molecules as potential inhibitors of the NCS-1/Ric8a interaction. The aminophenothiazine FD44 interferes with NCS-1/Ric8a binding, and it restores normal synapse number and associative learning in a Drosophila FXS model. The synaptic effects elicited by FD44 feeding are consistent with the genetic manipulation of NCS-1. The crystal structure of NCS-1 bound to FD44 and the structure- function studies performed with structurally close analogs explain the FD44 specificity and the mechanism of inhibition, in which the small molecule stabilizes a mobile C-Terminal helix inside a hydrophobic crevice of NCS-1 to impede Ric8a interaction. Our study shows the drugability of the NCS-1/Ric8a interface and uncovers a suitable region in NCS-1 for development of additional drugs of potential use on FXS and related synaptic disorders.

Glycogen synthase kinase 3 ß (GSK-3ß) is a central target in several unmet diseases. To increase the specificity of GSK-3ß inhibitors in chronic treatments, we developed small molecules allowing subtle modulation of GSK-3ß activity. Design synthesis, structure¿activity relationships, and binding mode of quinoline-3-carbohydrazide derivatives as allosteric modulators of GSK-3ß are presented here. Furthermore, we show how allosteric binders may overcome the ß-catenin side effects associated with strong GSK-3ß inhibition. The therapeutic potential of some of these modulators has been tested in human samples from patients with congenital myotonic dystrophy type 1 (CDM1) and spinal muscular atrophy (SMA) patients. We found that compound 53 improves delayed myogenesis in CDM1 myoblasts, while compounds 1 and 53 have neuroprotective properties in SMA-derived cells. These findings suggest that the allosteric modulators of GSK-3ß may be used for future development of drugs for DM1, SMA, and other chronic diseases where GSK-3ß inhibition exhibits therapeutic effects., This work was financially supported by MINECO (grant no. SAF2012-37979-C03-01 and SAF2016-76693-R to A.M. and IJCI-2014-20767 to V.P.). CCHMC funds L.T. A.M. and C.G. are members of the CIB Intramural Program “Molecular Machines for Better Life” (MACBET).

19 p.-12 fig.-5 tab. Ponzoni, Ignacio et al., Quantitative structure–activity relationship modeling using machine learning techniques constitutes a complex computational problem, where the identification of the most informative molecular descriptors for predicting a specific target property plays a critical role. Two main general approaches can be used for this modeling procedure: feature selection and feature learning. In this paper, a performance comparative study of two state-of-art methods related to these two approaches is carried out. In particular, regression and classification models for three different issues are inferred using both methods under different experimental scenarios: two drug-like properties, such as blood-brainbarrier and human intestinal absorption, and enantiomeric excess, as a measurement of purity used for chiral substances. Beyond the contrastive analysis of feature selection and feature learning methods as competitive approaches, the hybridization of these strategies is also evaluated based on previous results obtained in material sciences. From the experimental results, it can be concluded that there is not a clear winner between both approaches because the performance depends on the characteristics of the compound databases used for modeling. Nevertheless, in several cases, it was observed that the accuracy of the models can be improved by combining both approaches when the molecular descriptor sets provided by feature selection and feature learning contain complementary information., This work was supported by Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) [Grant number 112-2012-0100471 and PIP 114-2011-0100362], the Secretaría de Ciencia y Tecnología of the Universidad Nacional del Sur (UNS) [Grant numbers 24/N032, 24/ZN26] and MINECO (Spain) [project CTQ2015-66313-R and CTQ2015-66954-P MINECO/FEDER]. Dr. Ponzoni did this work as a visiting researcher at the Centro de Investigaciones Biológicas (CIB-CSIC) at Madrid (Spain). The authors would like to express their acknowledgment to the 6° Programa de Movilidad Docente a Madrid of the Secretaría de Políticas Universitarias (SPU), Ministerio de Educación de la República Argentina, for their economic support given for Dr. Ponzoni’s visit. Víctor Sebastián-Pérez acknowledges a predoctoral fellowship from MINECO [FPU15/01465].

Phosphodiesterase (PDE) 7 is involved in proinflammatory processes, being widely expressed both on lymphocytes and on certain brain regions. Specific inhibitors of PDE7 have been recently reported as potential new drugs for the treatment of neurological disorders because of their ability to increase intracellular levels of cAMP and thus to modulate the inflammatory process, as a neuroprotective well-established strategy. Multiple sclerosis is an unmet disease in which pathologies on the immune system, T-cells, and specific neural cells are involved simultaneously. Therefore, PDE7 inhibitors able to interfere with all these targets may represent an innovative therapy for this pathology. Here, we report a new chemically diverse family of heterocyclic PDE7 inhibitors, discovered and optimized by using molecular modeling studies, able to increase cAMP levels in cells, decrease inflammatory activation on primary neural cultures, and also attenuate the clinical symptoms in the experimental autoimmune encephalomyelitis (EAE) mouse model. These results led us to propose the use of PDE7 inhibitors as innovative therapeutic agents for the treatment of multiple sclerosis. © 2012 American Chemical Society., The authors gratefully acknowledge the financial support of Ministry of Science and Innovation (MICINN), projects nos. SAF2009-13015-C02-01, SAF2009-13015-C02-02, SAF2010-16365, SAF2009-1152, and PI10-01874; Instituto de Salud Carlos III (ISCiii), project no. RD07/0060/0015 (RETICS program) and CIBERNED; Fundación Española para la Ciencia y la Tecnología (FECYT), project no. FCT-09-INC-0367. M.R. and D. I. P. acknowledge pre- and post-doctoral fellowship from the CSIC (JAE program) respectively.

A simple and efficient synthetic method for the preparation of quinazoline type phosphodiesterase 7 (PDE7) inhibitors, based on microwave irradiation, has been developed. The use of this methodology improved yields and reaction times, providing a scalable procedure. These compounds are pharmacologically interesting because of their in vivo efficacy both in spinal cord injury and Parkinson's disease models, as shown in previous studies from our group. Herein we describe for the first time that administration of one of the PDE7 inhibitors here optimized, 3-phenyl-2,4-dithioxo-1,2,3,4-tetrahydroquinazoline (compound 5), ameliorated brain damage and improved behavioral outcome in a permanent middle cerebral artery occlusion (pMCAO) stroke model. Furthermore, we demonstrate that these PDE7 inhibitors are potent anti-inflammatory as well as neuroprotective agents in primary cultures of neural cells. These results led us to propose PDE7 inhibitors as a new class of therapeutic agents for neuroprotection., The authors gratefully acknowledge the financial support of Ministry of Science and Innovation (MICINN), projects nos. SAF2007-62811, SAF2009-13015-C02-01, SAF2009-08145 and SAF2010-16365; Instituto de Salud Carlos III (ISCiii), project no. RD07/0060/0015 and RD06/0026/0005 (RETICS program) and CIBERNED; Fundación Española para la Ciencia y la Tecnología (FECYT), project no. FCT-09-INC-0367 and Consejo Superior de Investigaciones Científicas (CSIC), project no. PIE 200780I012. M. R. and D. I. P. acknowledge pre- and post-doctoral fellowship from the CSIC (JAE program) respectively. J. G. Z. was supported by the Programme Alban, scholarship No. E07D400805CO. BRAINco Biopharma is acknowledged.