A-series agent A-234: initial in vitro and in vivo characterization.

A-series agent A-234 belongs to a new generation of nerve agents. The poisoning of a former Russian spy Sergei Skripal and his daughter in Salisbury, England, in March 2018 led to the inclusion of A-234 and other A-series agents into the Chemical Weapons Convention. Even though five years have already passed, there is still very little information on its chemical properties, biological activities, and treatment options with established antidotes. In this article, we first assessed A-234 stability in neutral pH for subsequent experiments. Then, we determined its inhibitory potential towards human recombinant acetylcholinesterase (HssAChE; EC 3.1.1.7) and butyrylcholinesterase (HssBChE; EC 3.1.1.8), the ability of HI-6, obidoxime, pralidoxime, methoxime, and trimedoxime to reactivate inhibited cholinesterases (ChEs), its toxicity in rats and therapeutic effects of different antidotal approaches. Finally, we utilized molecular dynamics to explain our findings. The results of spontaneous A-234 hydrolysis showed a slow process with a reaction rate displaying a triphasic course during the first 72 h (the residual concentration 86.2%). A-234 was found to be a potent inhibitor of both human ChEs (HssAChE IC50 = 0.101 ± 0.003 µM and HssBChE IC50 = 0.036 ± 0.002 µM), whereas the five marketed oximes have negligible reactivation ability toward A-234-inhibited HssAChE and HssBChE. The acute toxicity of A-234 is comparable to that of VX and in the context of therapy, atropine and diazepam effectively mitigate A-234 lethality. Even though oxime administration may induce minor improvements, selected oximes (HI-6 and methoxime) do not reactivate ChEs in vivo. Molecular dynamics implies that all marketed oximes are weak nucleophiles, which may explain the failure to reactivate the A-234 phosphorus-serine oxygen bond characterized by low partial charge, in particular, HI-6 and trimedoxime oxime oxygen may not be able to effectively approach the A-234 phosphorus, while pralidoxime displayed low interaction energy. This study is the first to provide essential experimental preclinical data on the A-234 compound.

Single-Cell Profiling Indicates a Proinflammatory Role of Meningeal Ectopic Lymphoid Tissue in Experimental Autoimmune Encephalomyelitis.

BACKGROUND AND OBJECTIVES: The factors that drive progression in multiple sclerosis (MS) remain obscure. Identification of key properties of meningeal inflammation will contribute to a better understanding of the mechanisms of progression and how to prevent it. METHODS: Applying single-cell RNA sequencing, we compared gene expression profiles in immune cells from meningeal ectopic lymphoid tissue (mELT) with those from secondary lymphoid organs (SLOs) in spontaneous chronic experimental autoimmune encephalomyelitis (EAE), an animal model of MS. RESULTS: Generally, mELT contained the same immune cell types as SLOs, suggesting a close relationship. Preponderance of B cells over T cells, an increase in regulatory T cells and granulocytes, and a decrease in naïve CD4+ T cells characterize mELT compared with SLOs. Differential gene expression analysis revealed that immune cells in mELT show a more activated and proinflammatory phenotype compared with their counterparts in SLOs. However, the increase in regulatory T cells and upregulation of immunosuppressive genes in most immune cell types indicate that there are mechanisms in place to counter-regulate the inflammatory events, keeping the immune response emanating from mELT in check. DISCUSSION: Common features in immune cell composition and gene expression indicate that mELT resembles SLOs and may be regarded as a tertiary lymphoid tissue. Distinct differences in expression profiles suggest that mELT rather than SLOs is a key driver of CNS inflammation in spontaneous EAE. Our data provide a starting point for further exploration of molecules or pathways that could be targeted to disrupt mELT formation.

Nanomolar Benzothiazole-Based Inhibitors of 17ß-HSD10 with Cellular Bioactivity.

Multifunctional mitochondrial enzyme 17ß-hydroxysteroid dehydrogenase type 10 (17ß-HSD10) is a potential drug target for the treatment of various pathologies. The most discussed is the pathology associated with Alzheimer's disease (AD), where 17ß-HSD10 overexpression and its interaction with amyloid-ß peptide contribute to mitochondrial dysfunction and neuronal stress. In this work, a series of new benzothiazole-derived 17ß-HSD10 inhibitors were designed based on the structure-activity relationship analysis of formerly published inhibitors. A set of enzyme-based and cell-based methods were used to evaluate the inhibitory potency of new compounds, their interaction with the enzyme, and their cytotoxicity. Most compounds exhibited significantly a higher inhibitory potential compared to published benzothiazolyl ureas and good target engagement in a cellular environment accompanied by low cytotoxicity. The best hits displayed mixed-type inhibition with half maximal inhibitory concentration (IC50) values in the nanomolar range for the purified enzyme (3-7, 15) and/or low micromolar IC50 values in the cell-based assay (6, 13-16).

Human MCTS1-dependent translation of JAK2 is essential for IFN-γ immunity to mycobacteria.

Human inherited disorders of interferon-gamma (IFN-γ) immunity underlie severe mycobacterial diseases. We report X-linked recessive MCTS1 deficiency in men with mycobacterial disease from kindreds of different ancestries (from China, Finland, Iran, and Saudi Arabia). Complete deficiency of this translation re-initiation factor impairs the translation of a subset of proteins, including the kinase JAK2 in all cell types tested, including T lymphocytes and phagocytes. JAK2 expression is sufficiently low to impair cellular responses to interleukin-23 (IL-23) and partially IL-12, but not other JAK2-dependent cytokines. Defective responses to IL-23 preferentially impair the production of IFN-γ by innate-like adaptive mucosal-associated invariant T cells (MAIT) and γδ T lymphocytes upon mycobacterial challenge. Surprisingly, the lack of MCTS1-dependent translation re-initiation and ribosome recycling seems to be otherwise physiologically redundant in these patients. These findings suggest that X-linked recessive human MCTS1 deficiency underlies isolated mycobacterial disease by impairing JAK2 translation in innate-like adaptive T lymphocytes, thereby impairing the IL-23-dependent induction of IFN-γ.

Physiologically relevant fluorescent assay for identification of 17ß-hydroxysteroid dehydrogenase type 10 inhibitors.

Mitochondrial enzyme 17ß-hydroxysteroid dehydrogenase type 10 (HSD10) is a potential molecular target for treatment of mitochondrial-related disorders such as Alzheimer's disease (AD). Its over-expression in AD brains is one of the critical factors disturbing the homeostasis of neuroprotective steroids and exacerbating amyloid beta (Aß)-mediated mitochondrial toxicity and neuronal stress. This study was focused on revalidation of the most potent HSD10 inhibitors derived from benzothiazolyl urea scaffold using fluorescent-based enzymatic assay with physiologically relevant substrates of 17ß-oestradiol and allopregnanolone. The oestradiol-based assay led to the identification of two nanomolar inhibitors (IC50 70 and 346 nM) differing from HSD10 hits revealed from the formerly used assay. Both identified inhibitors were found to be effective also in allopregnanolone-based assay with non-competitive or uncompetitive mode of action. In addition, both inhibitors were confirmed to penetrate the HEK293 cells and they were able to inhibit the HSD10 enzyme in the cellular environment. Both molecules seem to be potential lead structures for further research and development of HDS10 inhibitors.

Development of submicromolar 17ß-HSD10 inhibitors and their in vitro and in vivo evaluation.

17ß-hydroxysteroid dehydrogenase type 10 (17ß-HSD10) is a multifunctional mitochondrial enzyme and putative drug target for the treatment of various pathologies including Alzheimer's disease or some types of hormone-dependent cancer. In this study, a series of new benzothiazolylurea-based inhibitors were developed based on the structure-activity relationship (SAR) study of previously published compounds and predictions of their physico-chemical properties. This led to the identification of several submicromolar inhibitors (IC50 ∼0.3 µM), the most potent compounds within the benzothiazolylurea class known to date. The positive interaction with 17ß-HSD10 was further confirmed by differential scanning fluorimetry and the best molecules were found to be cell penetrable. In addition, the best compounds weren't found to have additional effects for mitochondrial off-targets and cytotoxic or neurotoxic effects. The two most potent inhibitors 9 and 11 were selected for in vivo pharmacokinetic study after intravenous and peroral administration. Although the pharmacokinetic results were not fully conclusive, it seemed that compound 9 was bioavailable after peroral administration and could penetrate into the brain (brain-plasma ratio 0.56).

Fragile sites, chromosomal lesions, tandem repeats, and disease.

Expanded tandem repeat DNAs are associated with various unusual chromosomal lesions, despiralizations, multi-branched inter-chromosomal associations, and fragile sites. Fragile sites cytogenetically manifest as localized gaps or discontinuities in chromosome structure and are an important genetic, biological, and health-related phenomena. Common fragile sites (∼230), present in most individuals, are induced by aphidicolin and can be associated with cancer; of the 27 molecularly-mapped common sites, none are associated with a particular DNA sequence motif. Rare fragile sites ( ≳ 40 known), ≤ 5% of the population (may be as few as a single individual), can be associated with neurodevelopmental disease. All 10 molecularly-mapped folate-sensitive fragile sites, the largest category of rare fragile sites, are caused by gene-specific CGG/CCG tandem repeat expansions that are aberrantly CpG methylated and include FRAXA, FRAXE, FRAXF, FRA2A, FRA7A, FRA10A, FRA11A, FRA11B, FRA12A, and FRA16A. The minisatellite-associated rare fragile sites, FRA10B, FRA16B, can be induced by AT-rich DNA-ligands or nucleotide analogs. Despiralized lesions and multi-branched inter-chromosomal associations at the heterochromatic satellite repeats of chromosomes 1, 9, 16 are inducible by de-methylating agents like 5-azadeoxycytidine and can spontaneously arise in patients with ICF syndrome (Immunodeficiency Centromeric instability and Facial anomalies) with mutations in genes regulating DNA methylation. ICF individuals have hypomethylated satellites I-III, alpha-satellites, and subtelomeric repeats. Ribosomal repeats and subtelomeric D4Z4 megasatellites/macrosatellites, are associated with chromosome location, fragility, and disease. Telomere repeats can also assume fragile sites. Dietary deficiencies of folate or vitamin B12, or drug insults are associated with megaloblastic and/or pernicious anemia, that display chromosomes with fragile sites. The recent discovery of many new tandem repeat expansion loci, with varied repeat motifs, where motif lengths can range from mono-nucleotides to megabase units, could be the molecular cause of new fragile sites, or other chromosomal lesions. This review focuses on repeat-associated fragility, covering their induction, cytogenetics, epigenetics, cell type specificity, genetic instability (repeat instability, micronuclei, deletions/rearrangements, and sister chromatid exchange), unusual heritability, disease association, and penetrance. Understanding tandem repeat-associated chromosomal fragile sites provides insight to chromosome structure, genome packaging, genetic instability, and disease.

Non-covalent acetylcholinesterase inhibitors: In vitro screening and molecular modeling for novel selective insecticides.

Insecticides represent the most crucial element in the integrated management approach to malaria and other vector-borne diseases. The evolution of insect resistance to long-used substances and the toxicity of organophosphates (OPs) and carbamates are the main factors contributing to the development of new, environmentally safe pesticides. In our work, fourteen compounds of 7-methoxytacrine-tacrine heterodimers were tested for their insecticidal effect. Compounds were evaluated in vitro on insect acetylcholinesterase from Anopheles gambiae (AgAChE) and Musca domestica (MdAChE). The evaluation was executed in parallel with testing on human erythrocyte acetylcholinesterase (HssAChE) and human butyrylcholinesterase (HssBChE) using a modified Ellman's method. Compound efficacy was determined as IC50 values for the respective enzymes and selectivity indexes were expressed to compare the interspecies selectivity. Docking studies were performed to predict the binding modes of selected compounds. K1328 and K1329 provided high HssAChE/AgAChE selectivity outperforming standard pesticides (carbofuran and bendiocarb), and thus can be considered as suitable lead structure for novel anticholinesterase insecticides.

Randomized evaluation of decision support interventions for atrial fibrillation: Rationale and design of the RED-AF study.

BACKGROUND: Shared decision making (SDM) improves the likelihood that patients will receive care in a manner consistent with their priorities. To facilitate SDM, decision aids (DA) are commonly used, both to prepare a patient before their clinician visit, as well as to facilitate discussion during the visit. However, the relative efficacy of patient-focused or encounter-based DAs on SDM and patient outcomes remains largely unknown. We aim to directly estimate the comparative effectiveness of two DA's on SDM observed in encounters to discuss stroke prevention strategies in patients with atrial fibrillation (AF). METHODS: The study aims to recruit 1200 adult patients with non-valvular AF who qualify for anticoagulation therapy, and their clinicians who manage stroke prevention strategies, in a 2x2 cluster randomized multi-center trial at six sites. Two DA's were developed as interactive, online, non-linear tools: a patient decision aid (PDA) to be used by patients before the encounter, and an encounter decision aid (EDA) to be used by clinicians with their patients during the encounter. Patients will be randomized to PDA or usual care; clinicians will be randomized to EDA or usual care. RESULTS: Primary outcomes are quality of SDM, patient decision making, and patient knowledge. Secondary outcomes include anticoagulation choice, adherence, and clinical events. CONCLUSION: This trial is the first randomized, head-to-head comparison of the effects of an EDA versus a PDA on SDM. Our results will help to inform future SDM interventions to improve patients' AF outcomes and experiences with stroke prevention strategies.

Charged pyridinium oximes with thiocarboxamide moiety are equally or less effective reactivators of organophosphate-inhibited cholinesterases compared to analogous carboxamides.

The organophosphorus antidotes, so-called oximes, are able to restore the enzymatic function of acetylcholinesterase (AChE) or butyrylcholinesterase (BChE) via cleavage of organophosphate from the active site of the phosphylated enzyme. In this work, the charged pyridinium oximes containing thiocarboxamide moiety were designed, prepared and tested. Their stability and pKa properties were found to be analogous to parent carboxamides (K027, K048 and K203). The inhibitory ability of thiocarboxamides was found in low µM levels for AChE and high µM levels for BChE. Their reactivation properties were screened on human recombinant AChE and BChE inhibited by nerve agent surrogates and paraoxon. One thiocarboxamide was able to effectively restore function of NEMP- and NEDPA-AChE, whereas two thiocarboxamides were able to reactivate BChE inhibited by all tested organophosphates. These results were confirmed by reactivation kinetics, where thiocarboxamides were proved to be effective, but less potent reactivators if compared to carboxamides.

Shared Decision Making in Cardiac Electrophysiology Procedures and Arrhythmia Management.

Shared decision making (SDM) has been advocated to improve patient care, patient decision acceptance, patient-provider communication, patient motivation, adherence, and patient reported outcomes. Documentation of SDM is endorsed in several society guidelines and is a condition of reimbursement for selected cardiovascular and cardiac arrhythmia procedures. However, many clinicians argue that SDM already occurs with clinical encounter discussions or the process of obtaining informed consent and note the additional imposed workload of using and documenting decision aids without validated tools or evidence that they improve clinical outcomes. In reality, SDM is a process and can be done without decision tools, although the process may be variable. Also, SDM advocates counter that the low-risk process of SDM need not be held to the high bar of demonstrating clinical benefit and that increasing the quality of decision making should be sufficient. Our review leverages a multidisciplinary group of experts in cardiology, cardiac electrophysiology, epidemiology, and SDM, as well as a patient advocate. Our goal is to examine and assess SDM methodology, tools, and available evidence on outcomes in patients with heart rhythm disorders to help determine the value of SDM, assess its possible impact on electrophysiological procedures and cardiac arrhythmia management, better inform regulatory requirements, and identify gaps in knowledge and future needs.

Derivatives of montanine-type alkaloids and their implication for the treatment of Alzheimer's disease: Synthesis, biological activity and in silico study.

Alzheimers disease (AD) is the most common neurodegenerative disorder, characterized by neuronal loss and cognitive impairment. Currently, very few drugs are available for AD treatment, and a search for new therapeutics is urgently needed. Thus, in the current study, twenty-eight new derivatives of montanine-type Amaryllidaceae alkaloids were synthesized and evaluated for their ability to inhibit human recombinant acetylcholinesterase (hAChE) and butyrylcholinesterase (hBuChE). Three derivatives (1n, 1o, and 1p) with different substitution patterns demonstrated significant selective inhibitory potency for hAChE (IC50 < 5 µM), and one analog, 1v, showed selective hBuChE inhibition activity (IC50 = 1.73 ± 0.05 µM). The prediction of CNS availability, as disclosed by the BBB score, suggests that the active compounds in this survey should be able pass through the blood-brain barrier (BBB). Cytotoxicity screening and docking studies were carried out for the two most pronounced cholinesterase inhibitors, 1n and 1v.

Amaryllidaceae Alkaloids of Norbelladine-Type as Inspiration for Development of Highly Selective Butyrylcholinesterase Inhibitors: Synthesis, Biological Activity Evaluation, and Docking Studies.

Alzheimer's disease (AD) is a multifactorial neurodegenerative condition of the central nervous system (CNS) that is currently treated by cholinesterase inhibitors and the N-methyl-d-aspartate receptor antagonist, memantine. Emerging evidence strongly supports the relevance of targeting butyrylcholinesterase (BuChE) in the more advanced stages of AD. Within this study, we have generated a pilot series of compounds (1-20) structurally inspired from belladine-type Amaryllidaceae alkaloids, namely carltonine A and B, and evaluated their acetylcholinesterase (AChE) and BuChE inhibition properties. Some of the compounds exhibited intriguing inhibition activity for human BuChE (hBuChE), with a preference for BuChE over AChE. Seven compounds were found to possess a hBuChE inhibition profile, with IC50 values below 1 µM. The most potent one, compound 6, showed nanomolar range activity with an IC50 value of 72 nM and an excellent selectivity pattern over AChE, reaching a selectivity index of almost 1400. Compound 6 was further studied by enzyme kinetics, along with in-silico techniques, to reveal the mode of inhibition. The prediction of CNS availability estimates that all the compounds in this survey can pass through the blood-brain barrier (BBB), as disclosed by the BBB score.

Pharmacokinetics of anti-infective agents during CytoSorb hemoadsorption.

Cytokine hemoadsorption might be beneficial in patients with sepsis. However, its effect on anti-infective agents' disposition remains largely unknown. We sought to determine the influence of hemoadsorption on the pharmacokinetics of common anti-infective agents. This is an interventional experimental study, conducted in 24 healthy pigs. Animals were randomly allocated to either hemoadsorption (cases) or sham extracorporeal circuit (controls) and to drug combinations (3 cases and 3 controls for each combination). Hemoadsorption was performed with CytoSorb (CytoSorbents Corporation, USA). We evaluated 17 drugs (clindamycin, fluconazole, linezolid, meropenem, piperacillin, anidulafungin, ganciclovir, clarithromycin, posaconazole, teicoplanin, tobramycin, ceftriaxone, ciprofloxacin, metronidazole, liposomal amphotericin B, flucloxacillin and cefepime). Repeated blood sampling from the extracorporeal circulation (adsorber inlet/outlet, sham circuit) was performed over six hours following administration. Total clearance and adsorber-specific clearance were computed. Hemoadsorption was associated with increased clearance of all study drugs, except ganciclovir. Its impact on total body clearance was considered as moderate for fluconazole (282%) and linezolid (115%), mild for liposomal amphotericin B (75%), posaconazole (32%) and teicoplanine (31%) and negligible for all other drugs. Hemoadsorber clearance declined over time, with even delayed desorption for beta-lactams. It was moderately correlated with drug's lipophilicity (p = 0.01; r2 = 0.43). Hemoadsorption with CytoSorb appears to increase to a clinically significant extent the clearance of five among 17 tested anti-infectives. Studies in human patients are required to confirm the need for dosage adjustment of these agents.

E4 Transfer (E=P, As) to Ni Complexes.

The use of [Cp''2 Zr(η1:1 -E4 )] (E=P (1 a), As (1 b), Cp''=1,3-di-tert-butyl-cyclopentadienyl) as phosphorus or arsenic source, respectively, gives access to novel stable polypnictogen transition metal complexes at ambient temperatures. The reaction of 1 a/1 b with [CpR NiBr]2 (CpR =CpBn (1,2,3,4,5-pentabenzyl-cyclopentadienyl), Cp''' (1,2,4-tri-tert-butyl-cyclopentadienyl)) was studied, to yield novel complexes depending on steric effects and stoichiometric ratios. Besides the transfer of the complete En unit, a degradation as well as aggregation can be observed. Thus, the prismane derivatives [(Cp'''Ni)2 (µ,η3:3 -E4 )] (2 a (E=P); 2 b (E=As)) or the arsenic containing cubane [(Cp'''Ni)3 (µ3 -As)(As4 )] (5) are formed. Furthermore, the bromine bridged cubanes of the type [(CpR Ni)3 {Ni(µ-Br)}(µ3 -E)4 ]2 (CpR =Cp''': 6 a (E=P), 6 b (E=As), CpR =CpBn : 8 a (E=P), 8 b (E=As)) can be isolated. Here, a stepwise transfer of En units is possible, with a cyclo-E4 2- ligand being introduced and unprecedented triple-decker compounds of the type [{(CpR Ni)3 Ni(µ3 -E)4 }2 (µ,η4:4 -E'4 )] (CpR =CpBn , Cp'''; E/E'=P, As) are obtained.

Shared medical appointments: Translating research into practice for patients treated with ablation therapy for atrial fibrillation.

BACKGROUND: People with atrial fibrillation (AF) have lower reported quality of life and increased risk of heart attack, death, and stroke. Lifestyle modifications can improve arrhythmia-free survival/symptom severity. Shared medical appointments (SMAs) have been effective at targeting lifestyle change in other chronic diseases and may be beneficial for patients with AF. OBJECTIVE: To determine if perceived self-management and satisfaction with provider communication differed between patients who participated in SMAs compared to patients in standard care. Secondary objectives were to examine differences between groups for knowledge about AF, symptom severity, and healthcare utilization. METHODS: We conducted a retrospective analysis of data collected where patients were assigned to either standard care (n = 62) or a SMA (n = 59). Surveys were administered at pre-procedure, 3, and 6 months. RESULTS: Perceived self-management was not significantly different at baseline (p = 0.95) or 6 months (p = 0.21). Patients in SMAs reported more knowledge gain at baseline (p = 0.01), and higher goal setting at 6 months (p = 0.0045). Symptom severity for both groups followed similar trends. CONCLUSION: Patients with AF who participated in SMAs had similar perceived self-management, patient satisfaction with provider communication, symptom severity, and healthcare utilization with their counterparts, but had a statistically significant improvement in knowledge about their disease.

Pyridinium-2-carbaldoximes with quinolinium carboxamide moiety are simultaneous reactivators of acetylcholinesterase and butyrylcholinesterase inhibited by nerve agent surrogates.

The pyridinium-2-carbaldoximes with quinolinium carboxamide moiety were designed and synthesised as cholinesterase reactivators. The prepared compounds showed intermediate-to-high inhibition of both cholinesterases when compared to standard oximes. Their reactivation ability was evaluated in vitro on human recombinant acetylcholinesterase (hrAChE) and human recombinant butyrylcholinesterase (hrBChE) inhibited by nerve agent surrogates (NIMP, NEMP, and NEDPA) or paraoxon. In the reactivation screening, one compound was able to reactivate hrAChE inhibited by all used organophosphates and two novel compounds were able to reactivate NIMP/NEMP-hrBChE. The reactivation kinetics revealed compound 11 that proved to be excellent reactivator of paraoxon-hrAChE better to obidoxime and showed increased reactivation of NIMP/NEMP-hrBChE, although worse to obidoxime. The molecular interactions of studied reactivators were further identified by in silico calculations. Molecular modelling results revealed the importance of creation of the pre-reactivation complex that could lead to better reactivation of both cholinesterases together with reducing particular interactions for lower intrinsic inhibition by the oxime.

Is It the Twilight of BACE1 Inhibitors?

ß-secretase (BACE1) has been regarded as a prime target for the development of amyloid beta (Aß) lowering drugs in the therapy of Alzheimer´s disease (AD). Although the enzyme was discovered in 1991 and helped to formulate the Aß hypothesis as one of the very important features of AD etiopathogenesis, progress in AD treatment utilizing BACE1 inhibitors has remained limited. Moreover, in the last years, major pharmaceutical companies have discontinued clinical trials of five BACE1 inhibitors that had been strongly perceived as prospective. In our review, the Aß hypothesis, the enzyme, its functions, and selected substrates are described. BACE1 inhibitors are classified into four generations. Those that underwent clinical trials displayed adverse effects, including weight loss, skin rashes, worsening of neuropsychiatric symptoms, etc. Some inhibitors could not establish a statistically significant risk-benefit ratio, or even scored worse than placebo. We still believe that drugs targeting BACE1 may still hide some potential, but a different approach to BACE1 inhibition or a shift of focus to modulation of its trafficking and/or post-translational modification should now be followed.

Effects of novel 17ß-hydroxysteroid dehydrogenase type 10 inhibitors on mitochondrial respiration.

Mitochondrial enzymes are targets of newly synthesized drugs being tested for the treatment of neurodegenerative disorders, such as Alzheimer's disease (AD). The enzyme 17ß-hydroxysteroid dehydrogenase type 10 (HSD10) is a multifunctional mitochondrial protein that is thought to play a role in the pathophysiology of AD and is one of the targets of new potential AD drugs. The in vitro effects of frentizole, riluzole, AG18051, and 42 novel modulators of HSD10 (potential AD drugs) on citrate synthase (CS) activity, monoamine oxidase (MAO) activity, complex I- or complex II-linked mitochondrial respiratory rate, and complex I activity were measured in isolated pig brain mitochondria. Based on their minimal inhibitory effects on the respiratory rate of mitochondria and CS and complex I activity, six novel compounds were selected for further testing. Assuming that inhibition of MAO-B could be a desirable effect of AD drugs, only AG18051 and one new compound met the criteria for MAO-B inhibition with minimal drug-induced effects on mitochondrial respiration. In conclusion, our in vitro screening of mitochondrial effect of novel potential AD drugs has enabled the selection of the most promising molecules for further testing that are relatively safe in terms of drug-induced mitochondrial toxicity.