Pills of Multi-Target H2S Donating Molecules for Complex Diseases.

Among the various drug discovery methods, a very promising modern approach consists in designing multi-target-directed ligands (MTDLs) able to modulate multiple targets of interest, including the pathways where hydrogen sulfide (H2S) is involved. By incorporating an H2S donor moiety into a native drug, researchers have been able to simultaneously target multiple therapeutic pathways, resulting in improved treatment outcomes. This review gives the reader some pills of successful multi-target H2S-donating molecules as worthwhile tools to combat the multifactorial nature of complex disorders, such as inflammatory-based diseases and cancer, as well as cardiovascular, metabolic, and neurodegenerative disorders.

3-Nitroatenolol: First Synthesis, Chiral Resolution and Enantiomers' Absolute Configuration.

4-Nitro and 7-nitro propranolol have been recently synthesized and characterized by us. (±)-4-NO2-propranolol has been shown to act as a selective antagonist of 6-nitrodopamine (6-ND) receptors in the right atrium of rats. As part of our follow-up to this study, herein, we describe the first synthesis of (±)-3-nitroatenolol as a probe to evaluate the potential nitration of atenolol by endothelium. Chiral chromatography was used to produce pure enantiomers. By using Riguera's method, which is based on the sign distribution of ΔδH, the absolute configuration of the secondary alcohol was determined.

Na+/Ca2+ exchanger isoform 1 takes part to the Ca2+-related prosurvival pathway of SOD1 in primary motor neurons exposed to beta-methylamino-L-alanine.

BACKGROUND: The cycad neurotoxin beta-methylamino-L-alanine (L-BMAA), one of the environmental trigger factor for amyotrophic lateral sclerosis/Parkinson-dementia complex (ALS/PDC), may cause neurodegeneration by disrupting organellar Ca2+ homeostasis. Through the activation of Akt/ERK1/2 pathway, the Cu,Zn-superoxide dismutase (SOD1) and its non-metallated form, ApoSOD1, prevent endoplasmic reticulum (ER) stress-induced cell death in motor neurons exposed to L-BMAA. This occurs through the rapid increase of intracellular Ca2+ concentration ([Ca2+]i) in part flowing from the extracellular compartment and in part released from ER. However, the molecular components of this mechanism remain uncharacterized. METHODS: By an integrated approach consisting on the use of siRNA strategy, Western blotting, confocal double- labeling immunofluorescence, patch-clamp electrophysiology, and Fura 2-/SBFI-single-cell imaging, we explored in rat motor neuron-enriched cultures the involvement of the plasma membrane proteins Na+/Ca2+ exchanger (NCX) and purinergic P2X7 receptor as well as that of the intracellular cADP-ribose (cADPR) pathway, in the neuroprotective mechanism of SOD1. RESULTS: We showed that SOD1-induced [Ca2+]i rise was prevented neither by A430879, a P2X7 receptor specific antagonist or 8-bromo-cADPR, a cell permeant antagonist of cADP-ribose, but only by the pan inhibitor of NCX, CB-DMB. The same occurred for the ApoSOD1. Confocal double labeling immunofluorescence showed a huge expression of plasmalemmal NCX1 and intracellular NCX3 isoforms. Furthermore, we identified NCX1 reverse mode as the main mechanism responsible for the neuroprotective ER Ca2+ refilling elicited by SOD1 and ApoSOD1 through which they promoted translocation of active Akt in the nuclei of a subset of primary motor neurons. Finally, the activation of NCX1 by the specific agonist CN-PYB2 protected motor neurons from L-BMAA-induced cell death, mimicking the effect of SOD1. CONCLUSION: Collectively, our data indicate that SOD1 and ApoSOD1 exert their neuroprotective effect by modulating ER Ca2+ content through the activation of NCX1 reverse mode and Akt nuclear translocation in a subset of primary motor neurons. Video Abstract.

Enhanced efficacy of formoterol-montelukast salt in relieving asthma features and in preserving ß2-agonists rescue therapy.

Adrenergic ß2-agonists represent a mainstay in asthma management. Their chronic use has been associated with decreased bronchoprotection and rebound hyperresponsiveness. Here we investigate on the possible therapeutic advantage of a pharmacological association of ß2-agonists with montelukast, a highly selective leukotriene receptor antagonist, in modulating bronchial reactivity and controlling asthma features. The study has been conducted in vitro and in vivo and also takes advantage of the synthesis of a salt that gave us the possibility to simultaneously administer in vivo formoterol and montelukast (MFS). In vitro studies demonstrate that montelukast (1) preserves ß2-agonist response in isolated bronchi by preventing homologous ß2-adrenoceptor desensitization; (2) reduces desensitization by modulating ß2-receptor translocation in bronchial epithelial cells. In vivo studies demonstrate that sensitized mice receiving formoterol or montelukast display a significant reduction in airway hyperresponsiveness, but the ß2-agonist relaxing response is still impaired. Allergen challenge causes ß2 heterologous desensitization that is further increased by treatment in vivo with formoterol. Conversely MFS not only inhibits airway hyperresponsiveness but it rescues the ß2-agonist response. Histological analysis confirms the functional data, demonstrating an enhanced therapeutic efficiency of MSF in controlling also pulmonary metaplasia and lung inflammation. MFS is efficacious also when sensitized mice received the drug by local administration. In conclusion, the data obtained evidenced a therapeutic advantage in the association of ß2-agonists with montelukast in the control of asthma-like features and a better rescue bronchodilation response to ß2-agonists.

Design, Synthesis and Evaluation of Novel Molecular Hybrids between Antiglaucoma Drugs and H2S Donors.

Glaucoma is a group of eye diseases consisting of optic nerve damage with corresponding loss of field vision and blindness. Hydrogen sulfide (H2S) is a gaseous neurotransmitter implicated in various pathophysiological processes. It is involved in the pathological mechanism of glaucomatous neuropathy and exerts promising effects in the treatment of this disease. In this work, we designed and synthetized new molecular hybrids between antiglaucoma drugs and H2S donors to combine the pharmacological effect of both moieties, providing a heightened therapy. Brinzolamide, betaxolol and brimonidine were linked to different H2S donors. The H2S-releasing properties of the new compounds were evaluated in a phosphate buffer solution by the amperometric approach, and evaluated in human primary corneal epithelial cells (HCEs) by spectrofluorometric measurements. Experimental data showed that compounds 1c, 1d and 3d were the hybrids with the best properties, characterized by a significant and long-lasting production of the gasotransmitter both in the aqueous solution (in the presence of L-cysteine) and in the intracellular environment. Because, to date, the donation of H2S by antiglaucoma H2S donor hybrids using non-immortalized corneal cells has never been reported, these results pave the way to further investigation of the potential efficacy of the newly synthesized compounds.

Synthesis, Chiral Resolution and Enantiomers Absolute Configuration of 4-Nitropropranolol and 7-Nitropropranolol.

We recently identified 6-nitrodopamine and other nitro-catecholamines (6-nitrodopa, 6-nitroadrenaline), indicating that the endothelium has the ability to nitrate the classical catecholamines (dopamine, noradrenaline, and adrenaline). In order to investigate whether drugs could be subject to the same nitration process, we synthesized 4-nitro- and 7-nitropropranolol as probes to evaluate the possible nitration of the propranolol by the endothelium. The separation of the enantiomers in very high yields and excellent enantiopurity was achieved by chiral HPLC. Finally, we used Riguera's method to determine the absolute configuration of the enantiomers, through double derivatization with MPA and NMR studies.

Synthesis, Docking Studies and Pharmacological Evaluation of Serotoninergic Ligands Containing a 5-Norbornene-2-Carboxamide Nucleus.

A new series of 5-norbornene-2-carboxamide derivatives was prepared and their affinities to the 5-HT1A, 5-HT2A, and 5-HT2C receptors were evaluated and compared to a previously synthesized series of derivatives characterized by exo-N-hydroxy-5-norbornene-2,3-dicarboximidenucleus, in order to identify selective ligands for the above-mentioned subtype receptors. Arylpiperazines represents one of the most important classes of 5-HT1AR ligands, and recent research concerning new derivatives has been focused on the modification of one or more portions of such pharmacophore. The combination of structural elements (heterocyclic nucleus, propyl chain and 4-substituted piperazine), known to be critical to the affinity to 5-HT1A receptors, and the proper selection of substituents led to compounds with high specificity and affinity towards serotoninergic receptors. The most active compounds were selected for further in vivo assays to determine their functional activity. Finally, to rationalize the obtained results, molecular docking studies were performed. The results of the pharmacological studies showed that Norbo-4 and Norbo-18 were the most active and promising derivatives for the serotonin receptor considered in this study.

Synthesis, docking studies, and pharmacological evaluation of 2-hydroxypropyl-4-arylpiperazine derivatives as serotoninergic ligands.

A new series of norbornene and exo-N-hydroxy-7-oxabicyclo[2.2.1]hept-5-ene-2,3-dicarboximide derivatives was prepared, and their affinities to the 5-HT1A , 5-HT2A , and 5-HT2C receptors were evaluated and compared with a previously synthesized series of derivatives characterized by the same nuclei, to identify selective ligands for the subtype receptors. Arylpiperazines represent one of the most important classes of 5-HT1A R ligands, and the research of new derivatives has been focused on the modification of one or more portions of this pharmacophore. The combination of structural elements (heterocyclic nucleus, hydroxyalkyl chain, and 4-substituted piperazine), known to be critical for the affinity to 5-HT1A receptors, and the proper selection of substituents resulted in compounds with high specificity and affinity toward serotoninergic receptors. The most active compounds were selected for further in vivo assays to determine their functional activity. Finally, to rationalize the obtained results, molecular docking studies were performed. The results of the pharmacological studies showed that 3e, 4j, and 4n were the most active and promising derivatives for the serotonin receptor considered in this study.

Antagonizing S1P3 Receptor with Cell-Penetrating Pepducins in Skeletal Muscle Fibrosis.

S1P is the final product of sphingolipid metabolism, which interacts with five widely expressed GPCRs (S1P1-5). Increasing numbers of studies have indicated the importance of S1P3 in various pathophysiological processes. Recently, we have identified a pepducin (compound KRX-725-II) acting as an S1P3 receptor antagonist. Here, aiming to optimize the activity and selectivity profile of the described compound, we have synthesized a series of derivatives in which Tyr, in position 4, has been substituted with several natural aromatic and unnatural aromatic and non-aromatic amino acids. All the compounds were evaluated for their ability to inhibit vascular relaxation induced by KRX-725 (as S1P3 selective pepducin agonist) and KRX-722 (an S1P1-selective pepducin agonist). Those selective towards S1P3 (compounds V and VII) were also evaluated for their ability to inhibit skeletal muscle fibrosis. Finally, molecular dynamics simulations were performed to derive information on the preferred conformations of selective and unselective antagonists.

Synthesis, docking studies, and pharmacological evaluation of 5HT2C ligands containing the N'-cyanoisonicotinamidine or N'-cyanopicolinamidine nucleus.

N'-Cyanoisonicotinamidine and N'-cyanopicolinamidine derivatives, linked to an arylpiperazine moiety, were prepared and their affinities to the 5-HT1A , 5-HT2A , and 5-HT2C receptors were evaluated. Several of the newly synthesized compounds, tested by binding studies, showed nanomolar affinity at the 5-HT1A and 5-HT2C receptors and moderate or no affinity for other relevant receptors (D1 , D2 , α1 , and α2 ). Compound 8e (Ki = 21.4 nM) was the most affine for the 5-HT2C receptor, showing, at the same time, a high selectivity with respect to the other receptors analyzed. Compounds 4a and 4c, instead, showed an interesting mixed 5-HT1A /5-HT2C activity with Ki values of 21.3/11.5 and 23.2/6.48 nM, respectively. The compounds with better affinity and selectivity binding profiles toward 5-HT2C (4a, 4c, 8b, and 8e) were selected for further in vivo assays to determine their functional activity. Finally, to rationalize the obtained results, molecular docking studies were performed. The results of the pharmacological studies showed that compounds 4a, 8b, and 8e exerted antidepressant-like effects and 4a and 8e revealed also significant anxiolytic properties. Among the developed derivatives, the most promising compound seems to be 4a, which displayed antipsychotic-, antidepressant- and anxiolytic-like properties. No side effects, like catalepsy, motor-impairment or ethanol-potentiating effects, were observed after the injection of the tested compounds.

Non-Natural Linker Configuration in 2,6-Dipeptidyl-Anthraquinones Enhances the Inhibition of TAR RNA Binding/Annealing Activities by HIV-1 NC and Tat Proteins.

The HIV-1 nucleocapsid (NC) protein represents an excellent molecular target for the development of anti-retrovirals by virtue of its well-characterized chaperone activities, which play pivotal roles in essential steps of the viral life cycle. Our ongoing search for candidates able to impair NC binding/annealing activities led to the identification of peptidyl-anthraquinones as a promising class of nucleic acid ligands. Seeking to elucidate the inhibition determinants and increase the potency of this class of compounds, we have now explored the effects of chirality in the linker connecting the planar nucleus to the basic side chains. We show here that the non-natural linker configuration imparted unexpected TAR RNA targeting properties to the 2,6-peptidyl-anthraquinones and significantly enhanced their potency. Even if the new compounds were able to interact directly with the NC protein, they manifested a consistently higher affinity for the TAR RNA substrate and their TAR-binding properties mirrored their ability to interfere with NC-TAR interactions. Based on these findings, we propose that the viral Tat protein, sharing the same RNA substrate but acting in distinct phases of the viral life cycle, constitutes an additional druggable target for this class of peptidyl-anthraquinones. The inhibition of Tat-TAR interaction for the test compounds correlated again with their TAR-binding properties, while simultaneously failing to demonstrate any direct Tat-binding capabilities. These considerations highlighted the importance of TAR RNA in the elucidation of their inhibition mechanism, rather than direct protein inhibition. We have therefore identified anti-TAR compounds with dual in vitro inhibitory activity on different viral proteins, demonstrating that it is possible to develop multitarget compounds capable of interfering with processes mediated by the interactions of this essential RNA domain of HIV-1 genome with NC and Tat proteins.

Propafenone quantification in human plasma by high-performance liquid chromatography coupled with electrospray tandem mass spectrometry in a bioequivalence study
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Propafenone is an antiarrhythmic drug applied to ventricular arrhythmias, initially recognized as a sodium channel blocker. This study aims to evaluate the bioequivalence of two propafenone formulations (300 mg tablet) in healthy subjects under non-fasting conditions. The study was conducted as an open, randomized, 2-period design with a 2-sequence (RT, TR) with a 1-week washout interval. The subjects were selected for the study after having their health status previously assessed by a clinical evaluation and laboratory tests (biochemical and hematological parameters, and urinalysis). Debrisoquine phenotype of healthy subjects was determined by analysis of urinary excretion of debrisoquine and its major metabolite, 4-hydroxydebrisoquine. A single propafenone tablet (300 mg) was given in each occasion. Plasma propafenone concentrations were analyzed by liquid chromatography coupled to tandem mass spectrometry (HPLC/MS/MS) with positive ion electrospray ionization using multiple reactions monitoring (MRM). The geometric mean and 90% confidence intervals (CI) of propafenone/Ritmonorm® (T/R) percent ratio were 100.44% (88.39 - 114.13%) for AUClast, 99.84% (90.31 - 110.36%) for AUCinf, and 99.30% (90.08 - 109.47%) for Cmax. Since the 90% CI for Cmax, AUClast, and AUCinf ratios were all inside the 80 - 125% interval proposed by the US Food and Drug Administration Agency, it was concluded that the propafenone formulation elaborated by Biolab Sanus Farmacêutica Ltda. is bioequivalent to Ritmonorm® formulation for both the rate and the extent of absorption. The drug was well tolerated by the subjects, indicating that it is safe to perform propafenone bioequivalence studies in healthy subjects with intermediate/extensive metabolism.
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Activity of human kallikrein-related peptidase 6 (KLK6) on substrates containing sequences of basic amino acids. Is it a processing protease?

Human kallikrein 6 (KLK6) is highly expressed in the central nervous system and with elevated level in demyelinating disease. KLK6 has a very restricted specificity for arginine (R) and hydrolyses myelin basic protein, protein activator receptors and human ionotropic glutamate receptor subunits. Here we report a previously unreported activity of KLK6 on peptides containing clusters of basic amino acids, as in synthetic fluorogenic peptidyl-Arg-7-amino-4-carbamoylmethylcoumarin (peptidyl-ACC) peptides and FRET peptides in the format of Abz-peptidyl-Q-EDDnp (where Abz=ortho-aminobenzoic acid and Q-EDDnp=glutaminyl-N-(2,4-dinitrophenyl) ethylenediamine), in which pairs or sequences of basic amino acids (R or K) were introduced. Surprisingly, KLK6 hydrolyzed the fluorogenic peptides Bz-A-R↓R-ACC and Z-R↓R-MCA between the two R groups, resulting in non-fluorescent products. FRET peptides containing furin processing sequences of human MMP-14, nerve growth factor (NGF), Neurotrophin-3 (NT-3) and Neurotrophin-4 (NT-4) were cleaved by KLK6 at the same position expected by furin. Finally, KLK6 cleaved FRET peptides derived from human proenkephalin after the KR, the more frequent basic residues flanking enkephalins in human proenkephalin sequence. This result suggests the ability of KLK6 to release enkephalin from proenkephalin precursors and resembles furin a canonical processing proteolytic enzyme. Molecular models of peptides were built into the KLK6 structure and the marked preference of the cut between the two R of the examined peptides was related to the extended conformation of the substrates.

New 5-HT1A, 5HT2A and 5HT2C receptor ligands containing a picolinic nucleus: Synthesis, in vitro and in vivo pharmacological evaluation.

Picolinamide derivatives, linked to an arylpiperazine moiety, were prepared and their affinity to 5-HT1A, 5-HT2A and 5-HT2C receptors was evaluated. The combination of structural elements (heterocyclic nucleus, alkyl chain and 4-substituted piperazine), known to play critical roles in affinity for serotoninergic receptors, and the proper selection of substituents led to compounds with high specificity and affinity towards serotoninergic receptors. In binding studies, several molecules showed high affinity in nanomolar and subnanomolar range at 5-HT1A, 5-HT2A and 5-HT2C receptors and moderate or no affinity for other relevant receptors (D1, D2, α1 and α2). N-(2-(4-(pyrimidin-2-yl)piperazin-1-yl)ethyl)picolinamide (3o) with Ki=0.046nM, was the most affine and selective derivative for the 5-HT1A receptor compared to other serotoninergic dopaminergic and adrenergic receptors. N-(2-(4-(2-methoxyphenyl)piperazin-1-yl)ethyl)picolinamide (3b), instead, showed a subnanomolar affinity towards 5-HT2A with Ki=0.0224nM, whereas N-(2-(4-(bis(4-fluorophenyl)methyl)piperazin-1-yl)ethyl)picolinamide (3s) presented an attractive 5-HT2C affinity with Ki=0.8nM. Moreover, the compounds having better affinity and selectivity binding profiles towards 5-HT2A were selected and tested on rat ileum, to determine their effect on 5HT induced contractions. Those more selective towards 5-HT1A receptors were studied in vivo on several behavioral tests.

Development of 1,2,3-Triazole-Based Sphingosine Kinase Inhibitors and Their Evaluation as Antiproliferative Agents.

Two series of N-(aryl)-1-(hydroxyalkyl)pyrrolidine-2-carboxamides (2a-2g and 3a-3g) and 1,4-disubstituted 1,2,3-triazoles (5a-5h and 8a-8h) were synthesized. All the compounds, containing a lipophilic tail and a polar headgroup, were evaluated as sphingosine kinase (SphK) inhibitors by assessing their ability to interfere with the acetylcholine (Ach) induced relaxation of aortic rings pre-contracted with phenylephrine. Moreover, their antiproliferative activity was tested on several cell lines expressing both SphK1 and SphK2. Compounds 5h and 8f, identified as the most efficient antiproliferative agents, showed a different selectivity profile, with 8f being selective for SphK1.

Specificity studies on Kallikrein-related peptidase 7 (KLK7) and effects of osmolytes and glycosaminoglycans on its peptidase activity.

KLK7 substrate specificity was evaluated by families of fluorescence resonance energy transfer (FRET) peptides derived from Abz-KLFSSK-Q-EDDnp (Abz=ortho-aminobenzoic acid and Q-EDDnp=glutaminyl-N-[2,4-dinitrophenyl] ethylenediamine), by one bead-one peptide FRET peptide library in PEGA resin, and by the FRET peptide libraries Abz-GXX-Z-XX-Q-EDDnp (Z and X are fixed and random natural amino acids, respectively). KLK7 hydrolyzed preferentially F, Y or M, and its S1' and S2' subsites showed selectivity for hydrophilic amino acids, particularly R and K. This set of specificities was confirmed by the efficient kininogenase activity of KLK7 on Abz-MISLM(↓)KRPPGFSPF(↓)RSSRI-NH2 ((↓)indicates cleavage), hydrolysis of somatostatin and substance P and inhibition by kallistatin. The peptide Abz-NLY(↓)RVE-Q-EDDnp is the best synthetic substrate so far described for KLK7 [kcat/Km=455 (mMs)(-1)] that was designed from the KLK7 substrate specificity analysis. It is noteworthy that the NLYRVE sequence is present in human semaphorin 6B. KLK7 is activated by GAGs, inhibited by neutral salts, and activated by high concentration of kosmotropic salt. Pyroglutamic acid inhibited KLK7 (Ki=33mM) and is present in skin moisturizing factor (124mM). The KLK7 specificity described here and elsewhere reflects its participation in patho-physiological events in skin, the gastrointestinal tract and central nervous system, where KLK7 is significantly expressed.

Laparoscopic repair of hiatal hernia after minimally invasive esophagectomy.

INTRODUCTION: Minimally invasive esophagectomy for cancer decreases respiratory postoperative complications but seems to be associated with higher occurrence of hiatal hernia (HH). This study describes the incidence of this complication and the results of surgical repair. METHODS: Among 390 patients with esophageal cancer treated by esophagectomies with laparoscopic gastric dissection from 2000 to 2013, 32 (8.2%) patients developed HH. Demographics, diagnostic, surgical management and outcomes data were collected retrospectively. RESULTS: There were 25 men and 7 women with a median age of 60 years (39-78). The median time between esophagectomy and diagnosis of HH was 10 months (3 days-96 months). The most frequent symptoms at the time of diagnosis were pain (32%), dyspnea (21%) and vomiting (10%), while HH was asymptomatic in 10 patients. HH was located in the left chest in 97% of patients and involved either the transverse colon (91%), or omentum (25%) or the small bowel (12%). The operation included the reintegration of the viscera associated with the closure of the pillars (100%) and the establishment of a mesh (71%). The operation was carried out by laparoscopy in 19 (59%) patients and was conducted in emergency in 6 (19%) patients. No patient died, and the overall morbidity was 25%. After a median follow-up of 40 months (range 1-55), five patients died due to oncologic evolution and six (19%) patients had recurrence of HH who required a second operation. CONCLUSION: HH is a common complication after laparoscopic-assisted esophagectomy. Despite the use of mesh, postoperative morbidity and recurrence incidence remain high.

Large gastrointestinal stromal tumours of the stomach: Is laparoscopy reasonable?

BACKGROUND: Laparoscopic resection (LR) offers significant advantages compared to open resections for gastric gastrointestinal stromal tumours (GISTs). We aimed to evaluate whether LR outcomes jeopardised short and long-term outcomes of patients with large GISTs. PATIENTS AND METHODS: Among 50 patients undergoing surgery for gastric GISTs, 12 underwent LR for large GISTs (>5 cm). Their characteristics, perioperative results and survival were retrospectively compared to those of 22 patients who underwent LR for 'small GIST'. RESULTS: The two groups were similar regarding demographics, rate of wedge resection and mean blood loss. No patient required transfusion or conversion. Operative time was significantly increased in the 'large GIST' group (160 min vs 112 min, P = 0.001). Mean tumour size was significantly lower in the 'small GIST' group (8.4 cm vs 2.4 cm, P = 0.0001). Resection margins were negative. The mortality rate was nil and the overall morbidity rates was similar in both groups. Median length of hospital stay was significantly increased in the 'large GIST' group (7 days vs 5 days, P = 0.004). Median follow-up was 47 months and one patient in the 'small GIST' group developed recurrence and died during follow-up 11 years after surgery. No patient died during follow-up. CONCLUSIONS: LR for large GISTs is safe and technically feasible and does not negatively influence the oncologic course. Prospective randomised trials should be performed before using this approach in routine surgical care.

Synthesis, biological evaluation, and docking studies of PAR2-AP-derived pseudopeptides as inhibitors of kallikrein 5 and 6.

A series of protease activated receptor 2 activating peptide (PAR2-AP) derivatives (1-15) were designed and synthesized. The obtained compounds were tested on a panel of human kallikreins (hKLK1, hKLK2, hKLK5, hKLK6, and hKLK7) and were found completely inactive toward hKLK1, hKLK2, and hKLK7. Aiming to investigate the mode of interaction between the most interesting compounds and the selected hKLKs, docking studies were performed. The described compounds distinguish the different human tissue kallikreins with compounds 1 and 5 as the best hKLK5 and hKLK6 inhibitors, respectively.

Synthesis and in vitro pharmacological evaluation of novel 2-hydroxypropyl-4-arylpiperazine derivatives as serotoninergic ligands.

This paper reports the synthesis of new norbornene and exo-N-hydroxy-7-oxabicyclo[2.2.1]hept-5-ene-2,3-dicarboximide derivatives and their binding to the 5-HT1A , 5-HT2A , and 5-HT2C receptors, in order to identify selective ligands for these 5-hydroxytryptamine (5-HT, serotonine) receptor subtypes. The combination of structural elements (heterocyclic nucleus, hydroxyalkyl chain, and 4-substituted piperazine) known to be critical for affinity to 5-HT1A receptors and the proper selection of substituents led to compounds with high specificity and affinity toward serotoninergic receptors. The most active compounds were selected and further evaluated for their binding affinities to D1 , D2 dopaminergic and α1 , α2 adrenergic receptors. 4-[3-[4-(2-Furoyl)piperazin-1-yl]propoxy-2-ol]-4-aza-tricyclo[5.2.1.02,6]dec-8-ene-3,5-dione 3e with Ki = 5.04 ± 0.227 nM was the most active and selective derivative for the 5-HT2C receptor with respect to other serotonin receptors, and the most selective derivative versus dopaminergic and adrenergic receptors.