Structure prediction analysis of human core TIM23 complex reveals conservation of the protein translocation mechanism.

The majority of mitochondrial proteins are encoded in the nucleus, translated on cytosolic ribosomes, and subsequently targeted to the mitochondrial surface. Their further import into the organelle is facilitated by highly specialized protein translocases. Mitochondrial precursor proteins that are destined to the mitochondrial matrix and, to some extent, the inner membrane, utilize translocase of the inner membrane (TIM23). This indispensable import machinery has been extensively studied in yeast. The translocating unit of the TIM23 complex in yeast consists of two membrane proteins, Tim17 and Tim23. In contrast to previous findings, recent reports demonstrate the primary role of Tim17, rather than Tim23, in the translocation of newly synthesized proteins. Very little is known about human TIM23 translocase. Human cells have two orthologs of yeast Tim17, TIMM17A and TIMM17B. Here, using computational tools, we present the architecture of human core TIM23 variants with either TIMM17A or TIMM17B, forming two populations of highly similar complexes. The structures reveal high conservation of the core TIM23 complex between human and yeast. Interestingly, both TIMM17A and TIMM17B variants interact with TIMM23 and reactive oxygen species modulator 1 (ROMO1); a homolog of yeast Mgr2, a protein that can create a channel-like structure with Tim17. The high structural conservation of proteins that form the core TIM23 complex in yeast and humans raises an interesting question about mechanistic and functional differences that justify existence of the two variants of TIM23 in higher eukaryotes.

Innovative high fat diet establishes a novel zebrafish model for the study of visceral obesity.

Obesity is a complex chronic condition associated with multiple health risks, including visceral obesity, which is particularly detrimental. To gain insight into the mechanisms underlying obesity and its associated pathologies, a novel zebrafish model was established using an innovative high-fat diet (HFD). The primary goal was to induce visceral obesity in zebrafish and study the associated structural changes. To achieve this, a unique HFD consisting of 40% beef fat (HFD40) was developed and supplemented with magnesium aluminometasilicate to improve stability in a high humidity environment. Feeding regimens were initiated for both juvenile (starting at 2 weeks post-fertilization, lasting 18 weeks) and adult zebrafish (3 months post-fertilization, 8 weeks feeding duration). The innovative dietary approach successfully induced visceral obesity in both juvenile and adult zebrafish. This new model provides a valuable tool to study obesity-related pathologies, metabolic syndrome, and potential therapeutic interventions. Most importantly, the low-cost and easy-to-prepare composition of HFD40 was seamlessly incorporated into the water without the need for separation, was readily absorbed by the fish and induced rapid weight gain in the zebrafish population. In conclusion, this study presents a novel HFD40 composition enriched with a high beef fat concentration (40%), which represents a significant advance in the development of an experimental zebrafish model for the study of visceral obesity and associated metabolic changes.

New cyclic arylguanidine scaffolds as a platform for development of antimicrobial and antiviral agents.

According to WHO, infectious diseases are still a significant threat to public health. The combine effects of antibiotic resistance, immunopressure, and mutations within the bacterial and viral genomes necessitates the search for new molecules exhibiting antimicrobial and antiviral activities. Such molecules often contain cyclic guanidine moiety. As part of this work, we investigated the selected antimicrobial and antiviral activity of compounds from the cyclic arylguanidine group. Molecules were designed using molecular modeling and obtained using microwave radiation (MW) and sonochemical ()))) methods, in accordance with the previously developed pathways. The obtained compounds were screened for the ability to inhibit the growth of Escherichia coli, Acinetobacter baumannii, Pseudomonas aeruginosa, Staphylococcus aureus, Candida albicans, and Cryptococcus neoformans. The capacity to block the entry of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) into the host cell was probed using a bioluminescence immunoassay. The cytotoxicity and hemolytic properties of the most active molecules were also evaluated. The N-[2-(naphthalen-1-yl)ethyl]-5-phenyl-1,4,5,6-tetrahydro-1,3,5-triazin-2-amine 12j showed a high inhibition of Staphylococcus aureus and Cryptococcus neoformans (MIC ≤ 0.25 µg/mL), with no cytotoxic nor hemolytic effect (CC50, HC10 > 32 µm/mL). The CO-ADD platform identified many potentially useful molecules. A particularly rich population was examined in the database of the N.D. Zelinsky Institute of Organic Chemistry, in which 2517 active molecules (MIC ≤ 32 mg/mL) were found, of which about 10% are active at very low concentrations (MIC ≤ 1 mg/mL).

Eco-friendly synthesis of new olanzapine derivatives and evaluation of their anticancer potential.

New derivatives of the known antipsychotic drug olanzapine have been obtained as potential compounds with anticancer activity in two metabolically different breast cancer cell lines: MCF-7 and triple negative MDA-MB-231. The compounds were obtained under phase transfer catalysis (PTC) in the presence of microwave irradiation (MW) or ultrasound (")))"), evaluating the effect of solvents such as dimethylformamide, water, or choline chloride/urea (natural deep eutectic solvent, NaDES). In the best option, the compounds were obtained within 2 minutes with a yield of 57-86% in MW. Two of the obtained compounds which have a naphthalimide moiety and a pentyl (7) or hexyl chain (8) show pronounced cytotoxicity. Interestingly, neither olanzapine nor desmethylolanzapine (DOLA), which was one of the substrates for the synthesis reaction, showed any significant activity in the study.

Menopausal Status Contributes to Overall Survival in Endometrial Cancer Patients.

Endometrial cancer is the most common female genital tract malignancy in developed countries that occurs predominantly in postmenopausal women. The primary objective of our research was to investigate whether menopause status together with selected conventional prognostic indicators may contribute to overall (all-cause) survival in endometrial cancer patients. For this purpose, we applied the Cox proportional hazards regression model. Patients in advanced FIGO stage showed a relatively poor survival rate. The time since last menstruation and postoperative FSH concentration were identified as unfavorable prognostic factors in our model. Additionally, age at diagnosis, BMI value, adjuvant treatment (brachytherapy), and parity showed no impact on survival. To our knowledge, this is the first study to report a prognostic model for endometrial cancer including exact time from last menstruation as one of the prognostic variables. Due to the fact that there are no stratifying systems to reliably predict survival in patients with endometrial cancer, there is a strong need to revise and update existing models using complementary prognostic indicators. Collection of precise data on various risk factors may contribute to increased accuracy of artificial intelligence algorithms in order to personalize cancer care in the near future.

Eco-friendly methods of synthesis and preliminary biological evaluation of sulfonamide derivatives of cyclic arylguanidines.

The chemotype of arylsulfonamide derivatives of cyclic arylguanidines is a source of molecules with valuable biological activities, including antimicrobial and antitumor properties. The methods of the synthesis presented in the literature are characterized with low selectivity and high environmental nuisance. In this publication, we present a developed alternative and earlier undescribed pathway C, for the synthesis of arylsulfonamide derivatives of cyclic arylguanidines (N-(1H-arylimidazol-2-yl)arylsulfonamides and N-(1,4-dihydroquinazolin-2-yl)arylsulfonamides), including reaction between 2-(methylsulfanyl)-benzimidazole or 2-(methylsulfanyl)-3,4-dihydroquinazoline with arylsulfonamides. We also optimized previously reported methods; A (reaction of 2-aminobenzimidazole or 2-amino-3,4-dihydroquinazoline with arylsulfonyl chlorides) and B (reaction of dimethyl-(arylsulfonyl)carbonodithioimidate with aryldiamines). The conducted research allowed achieving two independent ecological and quick methods of obtaining the desired products. We used ecological methods of ultrasound-assisted or microwave synthesis, solvent-free reactions and a"green" reaction environment. In both pathways, it has proven advantageous to use H2O as the solvent and K2CO3 (1 or 3 equivalent) as the basic agent. In the sonochemical variant, the efficiency reached B: 37-89 %, C: 90 % in 60 min (P = 80 W and f = 40 kHz), while in the microwave synthesis it was B: 38-74 %, C: 63-85 % in 0.5-4 min (P = 50 W). Path A led to a complementary substitution product (i.e. 1-(arylsulfonyl)-1H-benzimidazol-2-amine or 1-(arylsulfonyl)-1,4-dihydroquinazolin-2-amine). We obtained a small group of compounds that were tested for cytotoxicity. The 10f (N-(1,4-dihydroquinazolin-2-yl)naphthalene-1-sulfonamide) showed cytotoxic activity towards human astrocytoma cell line 1321 N1. The calculated IC50 value was 8.22 µM at 24 h timepoint (doxorubicin suppressed 1321 N1 cell viability with IC50 of 1.1 µM). The viability of the cells exposed to 10f for 24 h dropped to 48.0 % compared to vehicle control, while the cells treated with doxorubicin experienced decline to 47.5 %. We assessed its potential usefulness in pharmacotherapy in the ADMET study, confirming its ability to cross the blood-brain barrier (Pe = 5.0 ± 1.5 × 10-6 cm/s) and the safety of its potential use in terms of DDI and hepatotoxicity.

Carlina oxide inhibits the interaction of SARS-CoV-2 S glycoprotein with angiotensin-converting enzyme 2.

Carlina acaulis plant is a potential target for the industrial production of phytochemicals that display applicability in pharmacy and medicine. The dry roots of C. acaulis contain up to 2 % of essential oil, the main component (up to 99 %) of which is carlina oxide [2-(3-phenylprop-1-ynyl)furan]. This compound shows multidirectional biological activity, including antibacterial and antifungal properties. Here, we evaluated the capacity of carlina oxide to inhibit the interaction between SARS-CoV-2 and its human receptor in vitro and in silico. A bioluminescent immunoassay was used to study the interaction between the receptor binding domain (RBD) of viral spike protein and the human angiotensin-converting enzyme 2 (ACE2), which serves as a receptor for viral entry. A dose-effect relationship was demonstrated, and a concentration of carlina oxide causing half-maximal inhibition (IC50) of the RBD:ACE2 interaction was determined to be equal to 234.2 µg/mL. Molecular docking suggested the presence of carlina oxide binding sites within the RBD and at the interface between RBD and ACE2. Finally, this study expands the list of potential applications of C. acaulis as a crop species.

Zirconium-Based Metal-Organic Frameworks as Acriflavine Cargos in the Battle against Coronaviruses─A Theoretical and Experimental Approach.

In this study, we present a complementary approach for obtaining an effective drug, based on acriflavine (ACF) and zirconium-based metal-organic frameworks (MOFs), against SARS-CoV-2. The experimental results showed that acriflavine inhibits the interaction between viral receptor-binding domain (RBD) of spike protein and angiotensin converting enzyme-2 (ACE2) host receptor driving viral cell entry. The prepared ACF@MOF composites exhibited low (MOF-808 and UiO-66) and high (UiO-67 and NU-1000) ACF loadings. The drug release profiles from prepared composites showed different release kinetics depending on the local pore environment. The long-term ACF release with the effective antiviral ACF concentration was observed for all studied ACF@MOF composites. The density functional theory (DFT) calculations allowed us to determine that π-π stacking together with electrostatic interaction plays an important role in acriflavine adsorption and release from ACF@MOF composites. The molecular docking results have shown that acriflavine interacts with several possible binding sites within the RBD and binding site at the RBD/ACE2 interface. The cytotoxicity and ecotoxicity results have confirmed that the prepared ACF@MOF composites may be considered potentially safe for living organisms. The complementary experimental and theoretical results presented in this study have confirmed that the ACF@MOF composites may be considered a potential candidate for the COVID-19 treatment, which makes them good candidates for clinical trials.

Deprogramming metabolism in pancreatic cancer with a bi-functional GPR55 inhibitor and biased ß2 adrenergic agonist.

Metabolic reprogramming contributes to oncogenesis, tumor growth, and treatment resistance in pancreatic ductal adenocarcinoma (PDAC). Here we report the effects of (R,S')-4'-methoxy-1-naphthylfenoterol (MNF), a GPR55 antagonist and biased ß2-adrenergic receptor (ß2-AR) agonist on cellular signaling implicated in proliferation and metabolism in PDAC cells. The relative contribution of GPR55 and ß2-AR in (R,S')-MNF signaling was explored further in PANC-1 cells. Moreover, the effect of (R,S')-MNF on tumor growth was determined in a PANC-1 mouse xenograft model. PANC-1 cells treated with (R,S')-MNF showed marked attenuation in GPR55 signal transduction and function combined with increased ß2-AR/Gαs/adenylyl cyclase/PKA signaling, both of which contributing to lower MEK/ERK, PI3K/AKT and YAP/TAZ signaling. (R,S')-MNF administration significantly reduced PANC-1 tumor growth and circulating L-lactate concentrations. Global metabolic profiling of (R,S')-MNF-treated tumor tissues revealed decreased glycolytic metabolism, with a shift towards normoxic processes, attenuated glutamate metabolism, and increased levels of ophthalmic acid and its precursor, 2-aminobutyric acid, indicative of elevated oxidative stress. Transcriptomics and immunoblot analyses indicated the downregulation of gene and protein expression of HIF-1α and c-Myc, key initiators of metabolic reprogramming in PDAC. (R,S')-MNF treatment decreased HIF-1α and c-Myc expression, attenuated glycolysis, shifted fatty acid metabolism towards ß-oxidation, and suppressed de novo pyrimidine biosynthesis in PANC-1 tumors. The results indicate a potential benefit of combined GPR55 antagonism and biased ß2-AR agonism in PDAC therapy associated with the deprogramming of altered cellular metabolism.

Pharmacological assessment of zebrafish-based cardiotoxicity models.

Cardiotoxicity remains the most common reason for failure during drug development. Recently, the zebrafish (Danio rerio) model has emerged for the evaluation of drug-dependent cardiotoxicity and for the identification of cardioprotective molecules. However, it remains unknown how closely the zebrafish-based results may be translated to humans. To tackle this issue, we established embryonic zebrafish models of doxorubicin-, adrenaline- and terfenadine-induced cardiotoxicity with unified dosing regimen which eventually enabled head-to-head comparison of the drugs. Subsequently, we determined whether human cardioprotective medications - dexrazoxane, metoprolol, carvedilol and valsartan - are able to manage heart dysfunction in zebrafish. Our results indicated that doxorubicin, adrenaline and terfenadine elicited overt signs of cardiotoxicity in fish, and we further showed that the blockade of the renin-angiotensin system and, to a lesser extent, ß-adrenergic system, ameliorated the heart disease in zebrafish. From the drug development standpoint, our work opens the possibility to determine the cardiovascular properties of tested compounds using the rapid and affordable zebrafish model.

Evidence against involvement of kynurenate branch of kynurenine pathway in pathophysiology of Fuchs' dystrophy and keratoconus.

Kynurenine aminotransferases (KAT) are enzymes catalyzing formation of kynurenic acid (KYNA) from kynurenine. KYNA is a Janus-faced molecule of high biological activity. On the one hand KYNA was identified as a UV filter and neuroprotectant with free radical scavenging properties, but on the other hand it may contribute to photodamage of lens proteins resulting in cataract formation. Fuchs endothelial corneal dystrophy (FECD) and keratoconus (KC) are common, vision threatening corneal dystrophies whose etiology is not fully understood. In our previous works, we confirmed the presence of KATs in the human cornea together with GPR35, a receptor for KYNA. This prompted us to investigate the potential changes in the expression of three isoforms: KAT I, KAT II, and KAT III in normal and FECD- and KC-affected corneas. Immunohistochemistry accompanied by gene expression data mining revealed that the levels of neither KAT I, KAT II, nor KAT III are affected in FECD and KC. This constitutes evidence against the involvement of KATs in the pathophysiology of FECD and KC.

Evaluation of ß-adrenergic ligands for development of pharmacological heart failure and transparency models in zebrafish.

Cardiovascular toxicity represents one of the most common reasons for clinical trial failure. Consequently, early identification of novel cardioprotective strategies could prevent the later-stage drug-induced cardiac side effects. The use of zebrafish (Danio rerio) in preclinical studies has greatly increased. High-throughput and low-cost of assays make zebrafish model ideal for initial drug discovery. A common strategy to induce heart failure is a chronic ß-adrenergic (ßAR) stimulation. Herein, we set out to test a panel of ßAR agonists to develop a pharmacological heart failure model in zebrafish. We assessed ßAR agonists with respect to the elicited mortality, changes in heart rate, and morphological alterations in zebrafish larvae according to Fish Embryo Acute Toxicity Test. Among the tested ßAR agonists, epinephrine elicited the most potent onset of heart stimulation (EC50 = 0.05 mM), which corresponds with its physiological role as catecholamine. However, when used at ten-fold higher dose (0.5 mM), the same compound caused severe heart rate inhibition (-28.70 beats/min), which can be attributed to its cardiotoxicity. Further studies revealed that isoetharine abolished body pigmentation at the sublethal dose of 7.50 mM. Additionally, as a proof of concept that zebrafish can mimic human cardiac physiology, we tested ßAR antagonists (propranolol, carvedilol, metoprolol, and labetalol) and verified that they inhibited fish heart rate in a similar fashion as in humans. In conclusion, we proposed two novel pharmacological models in zebrafish; i.e., epinephrine-dependent heart failure and isoetharine-dependent transparent zebrafish. We provided strong evidence that the zebrafish model constitutes a valuable tool for cardiovascular research.

Biginelli Reaction Synthesis of Novel Multitarget-Directed Ligands with Ca2+ Channel Blocking Ability, Cholinesterase Inhibition, Antioxidant Capacity, and Nrf2 Activation.

Novel multitarget-directed ligands BIGI 4a-d and BIGI 5a-d were designed and synthesized with a simple and cost-efficient procedure via a one-pot three-component Biginelli reaction targeting acetyl-/butyrylcholinesterases inhibition, calcium channel antagonism, and antioxidant ability. Among these multitarget-directed ligands, BIGI 4b, BIGI 4d, and BIGI 5b were identified as promising new hit compounds showing in vitro balanced activities toward the recognized AD targets. In addition, these compounds showed suitable physicochemical properties and a good druglikeness score predicted by Data Warrior software.

Gene Expression Data Mining Reveals the Involvement of GPR55 and Its Endogenous Ligands in Immune Response, Cancer, and Differentiation.

G protein-coupled receptor 55 (GPR55) is a recently deorphanized lipid- and peptide-sensing receptor. Its lipidic endogenous agonists belong to lysoglycerophospholipids, with lysophosphatidylinositol (LPI) being the most studied. Peptide agonists derive from fragmentation of pituitary adenylate cyclase-activating polypeptide (PACAP). Although GPR55 and its ligands were implicated in several physiological and pathological conditions, their biological function remains unclear. Thus, the aim of the study was to conduct a large-scale re-analysis of publicly available gene expression datasets to identify physiological and pathological conditions affecting the expression of GPR55 and the production of its ligands. The study revealed that regulation of GPR55 occurs predominantly in the context of immune activation pointing towards the role of the receptor in response to pathogens and in immune cell lineage determination. Additionally, it was revealed that there is almost no overlap between the experimental conditions affecting the expression of GPR55 and those modulating agonist production. The capacity to synthesize LPI was enhanced in various types of tumors, indicating that cancer cells can hijack the motility-related activity of GPR55 to increase aggressiveness. Conditions favoring accumulation of PACAP-derived peptides were different than those for LPI and were mainly related to differentiation. This indicates a different function of the two agonist classes and possibly the existence of a signaling bias.

Alterations in Kynurenine and NAD+ Salvage Pathways during the Successful Treatment of Inflammatory Bowel Disease Suggest HCAR3 and NNMT as Potential Drug Targets.

A meta-analysis of publicly available transcriptomic datasets was performed to identify metabolic pathways profoundly implicated in the progression and treatment of inflammatory bowel disease (IBD). The analysis revealed that genes involved in tryptophan (Trp) metabolism are upregulated in Crohn's disease (CD) and ulcerative colitis (UC) and return to baseline after successful treatment with infliximab. Microarray and mRNAseq profiles from multiple experiments confirmed that enzymes responsible for Trp degradation via the kynurenine pathway (IDO1, KYNU, IL4I1, KMO, and TDO2), receptor of Trp metabolites (HCAR3), and enzymes catalyzing NAD+ turnover (NAMPT, NNMT, PARP9, CD38) were synchronously coregulated in IBD, but not in intestinal malignancies. The modeling of Trp metabolite fluxes in IBD indicated that changes in gene expression shifted intestinal Trp metabolism from the synthesis of 5-hydroxytryptamine (5HT, serotonin) towards the kynurenine pathway. Based on pathway modeling, this manifested in a decline in mucosal Trp and elevated kynurenine (Kyn) levels, and fueled the production of downstream metabolites, including quinolinate, a substrate for de novo NAD+ synthesis. Interestingly, IBD-dependent alterations in Trp metabolites were normalized in infliximab responders, but not in non-responders. Transcriptomic reconstruction of the NAD+ pathway revealed an increased salvage biosynthesis and utilization of NAD+ in IBD, which normalized in patients successfully treated with infliximab. Treatment-related changes in NAD+ levels correlated with shifts in nicotinamide N-methyltransferase (NNMT) expression. This enzyme helps to maintain a high level of NAD+-dependent proinflammatory signaling by removing excess inhibitory nicotinamide (Nam) from the system. Our analysis highlights the prevalent deregulation of kynurenine and NAD+ biosynthetic pathways in IBD and gives new impetus for conducting an in-depth examination of uncovered phenomena in clinical studies.

Synthesis of new Hantzsch adducts showing Ca2+ channel blockade capacity, cholinesterase inhibition and antioxidant power.

Background: Alzheimer's disease is a chronic neurodegenerative chronic disease with a heavy social and economic impact in our developed societies, which still lacks an efficient therapy. Method: This paper describes the Hantzsch multicomponent synthesis of twelve alkyl hexahydro-quinoline-3-carboxylates, 4a-l, along with the evaluation of their Ca2+ channel blockade capacity, cholinesterase inhibition and antioxidant power. Results: Compound 4l showed submicromolar inhibition of butyrylcholinesterase, Ca2+ channel antagonism and an antioxidant effect. Conclusion: Compound 4l is an interesting compound that deserves further investigation for Alzheimer's disease therapy.

Type I and type II positive allosteric modulators of α7 nicotinic acetylcholine receptors induce antidepressant-like activity in mice by a mechanism involving receptor potentiation but not neurotransmitter reuptake inhibition. Correlation with mTOR intracellular pathway activation.

The aim of this study is to determine whether type I and type II positive allosteric modulators (PAMs) of α7 nicotinic acetylcholine receptors (nAChRs) induce antidepressant-like activity in mice after acute, subchronic, and chronic treatments, and to assess whether α7-PAMs inhibit neurotransmitter transporters and activate mTOR (mammalian target of rapamycin) and/or ERK (extracellular signal-regulated protein kinases) signaling. The forced swim (FST) and tail suspension (TST) test results indicated that NS-1738 (type I PAM), PNU-120596 and PAM-2 (type II PAMs) induce antidepressant-like activity after subchronic treatment, whereas PAM-2 was also active after chronic treatment. Methyllycaconitine (α7-antagonist) inhibited the observed effects, highlighting the involvement of α7 nAChRs in this process. Drug interaction studies showed synergism between PAM-2 and bupropion (antidepressant), but not between PAM-2 and DMXBA (α7-agonist). The studied PAMs showed no high affinity (< 1 µM) for the human dopamine, serotonin, and noradrenaline transporters, suggesting that transporter inhibition is not the underlying mechanism for the observed activity. To assess whether mTOR and ERK signaling pathways are involved in the activity of α7-PAMs, the phosphorylation status of key signaling nodes was determined in prefrontal cortex and hippocampus from mice chronically treated with PAM-2. In conclusion, the antidepressant-like activity of type I and type II PAMs is mediated by a mechanism involving α7 potentiation but not α7 desensitization or neurotransmitter transporter blockade, and is correlated with activation of both mTOR and ERK signaling pathways. These results support the view that α7-PAMs might be clinically used to ameliorate depression disorders .

Application of the SMALP technology to the isolation of GPCRs from low-yielding cell lines.

The ability of styrene-maleic acid (SMAc) co-polymers to spontaneously insert into biological membranes can be exploited to extract G protein-coupled receptors (GPCRs) embedded in styrene-maleic acid lipid particles (SMALPs), preserving the native environment around the protein and thus enhancing the feasibility of functional studies. So far, the SMALP technology has been primarily employed on non-mammalian cells and protocols are not optimized for adherent human cell lines, which cannot be harvested in large amounts. In this work, a fine investigation of key parameters affecting the formation of SMALPs was undertaken with the purpose of maximizing the yield of extraction of a recombinant form of human ß2-adrenergic receptor (rhß2AR) from HEK293T cells. The study highlighted an important influence of ionic strength on the membrane solubilization efficiency and GPCR purification yield of SMAc co-polymers: by lowering the salt concentration of all buffers used in previously published SMALP protocols, the water solubility and extraction efficiency of the selected SMAc co-polymer (commercially supplied as a potassium salt) were enhanced. In-line combination of size-exclusion chromatography (SEC) with immobilized metal affinity chromatography (IMAC) allowed further improvement of the final rhß2AR yield by reducing the loss of SMALP-embedded GPCRs during the fractionation and purification of SMALPs. The overall findings of this study show that the available SMALP protocols can be significantly optimized in several aspects in order to increase the efficiency of GPCR solubilization and isolation from low-yielding expression systems.

Kynurenine emerges from the shadows - Current knowledge on its fate and function.

Kynurenine (KYN), a main metabolite of tryptophan in mammals, is a direct precursor of kynurenic acid, anthranilic acid and 3-hydroxykynurenine (3-HK). Under physiological conditions, KYN is produced endogenously mainly in the liver by tryptophan 2,3-dioxygenase (TDO). Tumorigenesis and inflammatory conditions increase the activity of another KYN synthetizing enzyme, indoleamine 2,3-dioxygenase (IDO). However, knowledge about the exogenous sources and the fate of KYN in mammals is still limited. While most papers deal with the contribution of KYN to pathologies of the central nervous system, its role in the periphery has almost been ignored. KYN is a ligand for the aryl hydrocarbon receptor (AhR). As a receptor for KYN and its downstream metabolites, AhR is involved in several physiological and pathological conditions, including inflammation and carcinogenesis. Recent studies have shown that KYN suppresses immune response and is strongly involved in the process of carcinogenesis and tumour metastasis. Thus, inhibition of activity of the enzymes responsible for KYN synthesis, TDO, IDO or genetic manipulation leading to reduction of KYN synthesis, could be considered as innovative strategies for improving the efficacy of immunotherapy. Surprisingly, however, genetic or pharmacological approaches for reducing tryptophan catabolism to KYN do not necessarily result in decrease of KYN level in the main circulation. This review aims to summarize the current knowledge of KYN fate and function and to emphasize its importance for vital physiological and pathological processes.

Synthesis of Hantzsch Adducts as Cholinesterases and Calcium Flux inhibitors, Antioxidants and Neuroprotectives.

We report herein the design, synthesis, biological evaluation, and molecular modelling of new inhibitors of acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE), able to block Ca+2 channels also showing antioxidant and neuroprotective activities. The new MTDL, dialkyl 2,6-dimethyl-4-(4-((5-aminoalkyl)oxy)phenyl)-1,4-dihydropyridine-3,5-dicarboxylate 3a-p, have been obtained via Hantzsch reaction from appropriate and commercially available precursors. Pertinent biological analysis has prompted us to identify MTDL 3h [dimethyl-4-(4-((5-(4-benzylpiperidin-1-yl)pentyl)oxy)phenyl)-2,6-dimethyl-1,4-dihydropyridine-3,5-dicarboxylate] as an attractive inhibitor of AChE (1.8 µM) and BuChE (2 µM), Ca+2 channel antagonist (47.72% at 10 µM), and antioxidant (2.54 TE) agent, showing significant neuroprotection 28.68% and 38.29% against H2O2, and O/R, respectively, at 0.3 µM, thus being considered a hit-compound for further investigation in our search for anti-Alzheimer's disease agents.