N1-methylation of adenosine (m1A) in ND5 mRNA leads to complex I dysfunction in Alzheimer's disease.

One mechanism of particular interest to regulate mRNA fate post-transcriptionally is mRNA modification. Especially the extent of m1A mRNA methylation is highly discussed due to methodological differences. However, one single m1A site in mitochondrial ND5 mRNA was unanimously reported by different groups. ND5 is a subunit of complex I of the respiratory chain. It is considered essential for the coupling of oxidation and proton transport. Here we demonstrate that this m1A site might be involved in the pathophysiology of Alzheimer's disease (AD). One of the pathological hallmarks of this neurodegenerative disease is mitochondrial dysfunction, mainly induced by Amyloid ß (Aß). Aß mainly disturbs functions of complex I and IV of the respiratory chain. However, the molecular mechanism of complex I dysfunction is still not fully understood. We found enhanced m1A methylation of ND5 mRNA in an AD cell model as well as in AD patients. Formation of this m1A methylation is catalyzed by increased TRMT10C protein levels, leading to translation repression of ND5. As a consequence, here demonstrated for the first time, TRMT10C induced m1A methylation of ND5 mRNA leads to mitochondrial dysfunction. Our findings suggest that this newly identified mechanism might be involved in Aß-induced mitochondrial dysfunction.

RNA marker modifications reveal the necessity for rigorous preparation protocols to avoid artifacts in epitranscriptomic analysis.

The accurate definition of an epitranscriptome is endangered by artefacts resulting from RNA degradation after cell death, a ubiquitous yet little investigated process. By tracing RNA marker modifications through tissue preparation protocols, we identified a major blind spot from daily lab routine, that has massive impact on modification analysis in small RNAs. In particular, m6,6A and Am as co-varying rRNA marker modifications, appeared in small RNA fractions following rRNA degradation in vitro and in cellulo. Analysing mouse tissue at different time points post mortem, we tracked the progress of intracellular RNA degradation after cell death, and found it reflected in RNA modification patterns. Differences were dramatic between liver, where RNA degradation commenced immediately after death, and brain, yielding essentially undamaged RNA. RNA integrity correlated with low amounts of co-varying rRNA markers. Thus validated RNA preparations featured differentially modified tRNA populations whose information content allowed a distinction even among the related brain tissues cortex, cerebellum and hippocampus. Inversely, advanced cell death correlated with high rRNA marker content, and correspondingly little with the naïve state of living tissue. Therefore, unless RNA and tissue preparations are executed with utmost care, interpretation of modification patterns in tRNA and small RNA are prone to artefacts.

The P(III)-amidite based synthesis of stable isotope labeled mRNA-cap-structures enables their sensitive quantitation from brain tissue.

The 5' cap structure is crucial to mRNA function, with its diverse methylation patterns depending on the cellular state. Sensitive analytical methods are sought after to quantify this cap variety also referred to as cap epitranscriptome. To address a bottleneck for accurate and precise quantitation, we report a facile and fast access to high-quality synthetic standards via a new route, involving P(III)-amidite chemistry. A range of cap nucleotides and their stable heavy isotopic labeled analogues were derived from nucleoside diphosphates, which themselves were directly prepared in a one-step reaction sequence starting from unprotected nucleosides using a triphosphorylating reagent in combination with ethylenediamine. Considering a wider scope, the route also enables direct access to magic spot nucleotides and diphosphates of isoprenyl-alcohols. Stable-isotope labeled cap nucleotides derived from this route paved the way for the development of a highly sensitive LC-MS/MS method, applied to the characterization of mouse brain cap epitranscriptomes, which turned out to be very different from those of cultured cell lines of widespread use in the life sciences.

Analysis of hyperforin (St. John's wort) action at TRPC6 channel leads to the development of a new class of antidepressant drugs.

St. John's wort is an herb, long used in folk medicine for the treatment of mild depression. Its antidepressant constituent, hyperforin, has properties such as chemical instability and induction of drug-drug interactions that preclude its use for individual pharmacotherapies. Here we identify the transient receptor potential canonical 6 channel (TRPC6) as a druggable target to control anxious and depressive behavior and as a requirement for hyperforin antidepressant action. We demonstrate that TRPC6 deficiency in mice not only results in anxious and depressive behavior, but also reduces excitability of hippocampal CA1 pyramidal neurons and dentate gyrus granule cells. Using electrophysiology and targeted mutagenesis, we show that hyperforin activates the channel via a specific binding motif at TRPC6. We performed an analysis of hyperforin action to develop a new antidepressant drug that uses the same TRPC6 target mechanism for its antidepressant action. We synthesized the hyperforin analog Hyp13, which shows similar binding to TRPC6 and recapitulates TRPC6-dependent anxiolytic and antidepressant effects in mice. Hyp13 does not activate pregnan-X-receptor (PXR) and thereby loses the potential to induce drug-drug interactions. This may provide a new approach to develop better treatments for depression, since depression remains one of the most treatment-resistant mental disorders, warranting the development of effective drugs based on naturally occurring compounds.

Talk to Me-Interplay between Mitochondria and Microbiota in Aging.

The existence of mitochondria in eukaryotic host cells as a remnant of former microbial organisms has been widely accepted, as has their fundamental role in several diseases and physiological aging. In recent years, it has become clear that the health, aging, and life span of multicellular hosts are also highly dependent on the still-residing microbiota, e.g., those within the intestinal system. Due to the common evolutionary origin of mitochondria and these microbial commensals, it is intriguing to investigate if there might be a crosstalk based on preserved common properties. In the light of rising knowledge on the gut-brain axis, such crosstalk might severely affect brain homeostasis in aging, as neuronal tissue has a high energy demand and low tolerance for according functional decline. In this review, we summarize what is known about the impact of both mitochondria and the microbiome on the host's aging process and what is known about the aging of both entities. For a long time, bacteria were assumed to be immortal; however, recent evidence indicates their aging and similar observations have been made for mitochondria. Finally, we present pathways by which mitochondria are affected by microbiota and give information about therapeutic anti-aging approaches that are based on current knowledge.

[The Economic Evaluation of the GLICEMIA 2.0 Study as an Example of a Complex Intervention]. / Die gesundheitsökonomische Evaluation der GLICEMIA 2.0-Studie als Beispiel für eine komplexe Intervention.

BACKGROUND: A piggyback approach was used to evaluate the cost-effectiveness of the prevention program delivered at the point of care pharmacy in the GLICEMIA 2.0 study that sought to guide participants in the intervention group to improved glycemic control in type 2 diabetes with sustained incentivization of lifestyle changes, therapeutic compliance, and adherence. The control group received passive medication management and monitoring. METHODS: Primary endpoint of the GLICEMIA 2.0 study was the stabilization of HbA1c values. For health economic evaluation, incremental differences in output changes were examined, defined as the difference in the distribution of the HbA1c values between both groups over time. Direct program costs and anticipated indirect costs of service utilization were used as cost parameters. A net monetary benefit approach was used to validate cost-effectiveness thresholds via the formation of ICER values. RESULTS: The intervention group had significantly higher reductions in HbA1c-values. Risk stratification of initial HbA1c showed (short-term) cost effectiveness for initially higher HbA1c values. Due to the limited study period, no long-term differences in medical resource utilization could be assessed. CONCLUSION: The GLICEMIA program indicates considerable effectiveness potentials, especially for high-risk patients. The study design seems to have assisted the intervention group's adherence in contrast to the control group. Detailed impacts within the complex intervention could not be validated due to restrictions of the study design as a complex intervention. Overall, statements about effect sustainability and further utilization rates progressions are limited due to a lack of follow-up.

Neurotrophic Properties of Silexan, an Essential Oil from the Flowers of Lavender-Preclinical Evidence for Antidepressant-Like Properties.

BACKGROUND: Silexan, a special essential oil from flowering tops of lavandula angustifolia, is used to treat subsyndromal anxiety disorders. In a recent clinical trial, Silexan also showed antidepressant effects in patients suffering from mixed anxiety-depression (ICD-10 F41.2). Since preclinical data explaining antidepressant properties of Silexan are missing, we decided to investigate if Silexan also shows antidepressant-like effects in vitro as well as in vivo models. METHODS: We used the forced swimming test (FST) in rats as a simple behavioral test indicative of antidepressant activity in vivo. As environmental events and other risk factors contribute to depression through converging molecular and cellular mechanisms that disrupt neuronal function and morphology-resulting in dysfunction of the circuitry that is essential for mood regulation and cognitive function-we investigated the neurotrophic properties of Silexan in neuronal cell lines and primary hippocampal neurons. RESULTS: The antidepressant activity of Silexan (30 mg/kg BW) in the FST was comparable to the tricyclic antidepressant imipramine (20 mg/kg BW) after 9-day treatment. Silexan triggered neurite outgrowth and synaptogenesis in 2 different neuronal cell models and led to a significant increase in synaptogenesis in primary hippocampal neurons. Silexan led to a significant phosphorylation of protein kinase A and subsequent CREB phosphorylation. CONCLUSION: Taken together, Silexan demonstrates antidepressant-like effects in cellular as well as animal models for antidepressant activity. Therefore, our data provides preclinical evidence for the clinical antidepressant effects of Silexan in patients with mixed depression and anxiety.

Alterations in Tau Protein Level and Phosphorylation State in the Brain of the Autistic-Like Rats Induced by Prenatal Exposure to Valproic Acid.

Autism spectrum disorder (ASD) is a neurodevelopmental condition characterized by deficient social interaction and communication besides repetitive, stereotyped behaviours. A characteristic feature of ASD is altered dendritic spine density and morphology associated with synaptic plasticity disturbances. Since microtubules (MTs) regulate dendritic spine morphology and play an important role in spine development and plasticity the aim of the present study was to investigate the alterations in the content of neuronal α/ß-tubulin and Tau protein level as well as phosphorylation state in the valproic acid (VPA)-induced rat model of autism. Our results indicated that maternal exposure to VPA induces: (1) decrease the level of α/ß-tubulin along with Tau accumulation in the hippocampus and cerebral cortex; (2) excessive Tau phosphorylation and activation of Tau-kinases: CDK5, ERK1/2, and p70S6K in the cerebral cortex; (3) up-regulation of mTOR kinase-dependent signalling in the hippocampus and cerebral cortex of adolescent rat offspring. Moreover, immunohistochemical staining showed histopathological changes in neurons (chromatolysis) in both analysed brain structures of rats prenatally exposed to VPA. The observed changes in Tau protein together with an excessive decrease in α/ß-tubulin level may suggest destabilization and thus dysfunction of the MT cytoskeleton network, which in consequence may lead to the disturbance in synaptic plasticity and the development of autistic-like behaviours.

[Quality of Life and Satisfaction During the Diabetes Prevention Program GLICEMIA: a Cluster-Randomized, Controlled Trial]. / Lebensqualität und Zufriedenheit während der Teilnahme am Diabetes-Präventionsprogramm GLICEMIA: eine cluster-randomisierte, kontrollierte Studie.

OBJECTIVES: We aimed to assess the health-related quality of life as well as participant satisfaction during the pharmacy-based diabetes prevention program GLICEMIA. METHODS: GLICEMIA comprises 3 individual counseling sessions and 5 group-based lectures addressing a lifestyle modification. In a cluster-randomized controlled trial, GLICEMIA was compared with reduced standard information in the control group. After 12 months, the groups were compared regarding the diabetes risk score FINDRISC, health-related quality of life with the 12-item Short Form health survey (SF-12) and participant satisfaction. RESULTS: In total, the data of 1,087 participants were analyzed. During GLICEMIA, 38.9% reduced their FINDRISC whereas 20.9% reached this goal in the control group. Moreover, the physical quality of life improved significantly in the intervention group compared with the control group (adjusted effect size: 2.39 points, 95% CI 1.43-3.34). Participants of GLICEMIA who reduced their diabetes risk had enhanced mental and physical quality of life after one year. This was not observed in the control group. The overall benefit and satisfaction were rated very high in the intervention group. CONCLUSION: Participation in GLICEMIA results in a significant reduction of the diabetes risk according to the FINDRISC, as well as an improved physical and mental quality of life. The high satisfaction of the participants reflects the overall benefit. Nationwide implementation of the program is recommended.

Acid sphingomyelinase - a regulator of canonical transient receptor potential channel 6 (TRPC6) activity.

Recent investigations propose the acid sphingomyelinase (ASM)/ceramide system as a novel target for antidepressant action. ASM catalyzes the breakdown of the abundant membrane lipid sphingomyelin to the lipid messenger ceramide. This ASM-induced lipid modification induces a local shift in membrane properties, which influences receptor clustering and downstream signaling. Canonical transient receptor potential channels 6 (TRPC6) are non-selective cation channels located in the cell membrane that play an important role in dendritic growth, synaptic plasticity and cognition in the brain. They can be activated by hyperforin, an ingredient of the herbal remedy St. John's wort for treatment of depression disorders. Because of their role in the context of major depression, we investigated the crosstalk between the ASM/ceramide system and TRPC6 ion channels in a pheochromocytoma cell line 12 neuronal cell model (PC12 rat pheochromocytoma cell line). Ca2+ imaging experiments indicated that hyperforin-induced Ca2+ influx through TRPC6 channels is modulated by ASM activity. While antidepressants, known as functional inhibitors of ASM activity, reduced TRPC6-mediated Ca2+ influx, extracellular application of bacterial sphingomyelinase rebalanced TRPC6 activity in a concentration-related way. This effect was confirmed in whole-cell patch clamp electrophysiology recordings. Lipidomic analyses revealed a decrease in very long chain ceramide/sphingomyelin molar ratio after ASM inhibition, which was connected with changes in the abundance of TRPC6 channels in flotillin-1-positive lipid rafts as visualized by western blotting. Our data provide evidence that the ASM/ceramide system regulates TRPC6 channels likely by controlling their recruitment to specific lipid subdomains and thereby fine-tuning their physical properties.

Hyperforin: To Be or Not to Be an Activator of TRPC(6).

Meantime, it is well accepted that hyperforin, the chemical instable phloroglucinol derivative of Hypericum perforatum, St. John's wort, is the pharmacophore of St. John's wort extracts. With the decline of this scientific discussion, another controversial aspect has been arisen, the question regarding the underlying mechanism leading to the pharmacological profile of the plant extract used in therapy of depression. We will summarize the different concepts described for hyperforin's antidepressive activity. Starting with unspecific protein-independent mechanisms due to changes in pH, we will summarize data of protein-based concepts beginning with concepts based on involvement of a variety of proteins and will finally present concepts based on the modulation of a single protein.

Advances in clinical pharmacy education in Germany: a quasi-experimental single-blinded study to evaluate a patient-centred clinical pharmacy course in psychiatry.

BACKGROUND: The pharmacy profession has shifted towards patient-centred care. To meet the new challenges it is necessary to provide students with clinical competencies. A quasi-experimental single-blinded teaching and learning study was carried out using a parallel-group design to evaluate systematically the benefits of clinical teaching in pharmacy education in Germany. METHODS: A clinical pharmacy course on a psychiatric ward was developed and implemented for small student groups. The learning aims included: the improvement of patient and interdisciplinary communication skills and the identification and management of pharmaceutical care issues. The control group participated only in the preparation lecture, while the intervention group took part in the complete course. The effects were assessed by an objective structured clinical examination (OSCE) and a student satisfaction survey. RESULTS: The intervention group achieved significantly better overall results on the OSCE assessment (46.20 ± 10.01 vs. 26.58 ± 12.91 of a maximum of 90 points; p < 0.0001).The practical tasks had the greatest effect, as reflected in the outcomes of tasks 1-5 (34.94 ± 9.60 vs. 18.63 ± 10.24 of a maximum of 60 points; p < 0.0001). Students' performance on the theoretical tasks (tasks 6-10) was improved but unsatisfying in both groups considering the maximum score (11.50 ± 4.75 vs. 7.50 ± 4.00 of a maximum of 30 points; p < 0.0001). Of the students, 93% rated the course as practice-orientated, and 90% felt better prepared for patient contact. Many students suggested a permanent implementation and an extension of the course. CONCLUSIONS: The results suggest that the developed ward-based course provided learning benefits for clinical skills. Students' perception of the course was positive. Implementation into the regular clinical pharmacy curriculum is therefore advisable.

Modulation of mitochondrial dysfunction in neurodegenerative diseases via activation of nuclear factor erythroid-2-related factor 2 by food-derived compounds.

Oxidative stress and mitochondrial dysfunction are early events in the pathogenesis of neurodegenerative diseases, including Alzheimer's disease (AD), Parkinson's disease (PD), Huntington's disease (HD) and amyotrophic lateral sclerosis (ALS). Mitochondria are important key players in cellular function based on mitochondrial energy production and their major role in cell physiology. Since neurons are highly depending on mitochondrial energy production due to their high energy demand and their reduced glycolytic capacity mitochondrial dysfunction has fatal consequences for neuronal function and survival. The transcription factor nuclear factor erythroid-2-related factor 2 (Nrf2) is the major regulator of cellular response to oxidative stress. Activation of Nrf2 induces the transcriptional regulation of antioxidant response element (ARE)-dependent expression of a battery of cytoprotective and antioxidant enzymes and proteins. Moreover, activation of Nrf2 protects mitochondria from dysfunction and promotes mitochondrial biogenesis. Therefore, the Nrf2/ARE pathway has become an attractive target for the prevention and treatment of oxidative stress-related neurodegenerative diseases. Small food-derived inducers of the Nrf2/ARE pathway including l-sulforaphane from broccoli and isoliquiritigenin from licorice displayed promising protection of mitochondrial function in models of oxidative stress and neurodegenerative diseases and represent a novel approach to prevent and treat aging-associated neurodegenerative diseases.

Mitochondrial dysfunction: the missing link between aging and sporadic Alzheimer's disease.

Alzheimer's disease (AD) is a progressive neurodegenerative disease that represents the most common form of dementia among the elderly. Despite the fact that AD was studied for decades, the underlying mechanisms that trigger this neuropathology remain unresolved. Since the onset of cognitive deficits occurs generally within the 6th decade of life, except in rare familial case, advancing age is the greatest known risk factor for AD. To unravel the pathogenesis of the disease, numerous studies use cellular and animal models based on genetic mutations found in rare early onset familial AD (FAD) cases that represent less than 1 % of AD patients. However, the underlying process that leads to FAD appears to be distinct from that which results in late-onset AD. As a genetic disorder, FAD clearly is a consequence of malfunctioning/mutated genes, while late-onset AD is more likely due to a gradual accumulation of age-related malfunction. Normal aging and AD are both marked by defects in brain metabolism and increased oxidative stress, albeit to varying degrees. Mitochondria are involved in these two phenomena by controlling cellular bioenergetics and redox homeostasis. In the present review, we compare the common features observed in both brain aging and AD, placing mitochondrial in the center of pathological events that separate normal and pathological aging. We emphasize a bioenergetic model for AD including the inverse Warburg hypothesis which postulates that AD is a consequence of mitochondrial deregulation leading to metabolic reprogramming as an initial attempt to maintain neuronal integrity. After the failure of this compensatory mechanism, bioenergetic deficits may lead to neuronal death and dementia. Thus, mitochondrial dysfunction may represent the missing link between aging and sporadic AD, and represent attractive targets against neurodegeneration.

Enhanced Neuroplasticity by the Metabolic Enhancer Piracetam Associated with Improved Mitochondrial Dynamics and Altered Permeability Transition Pore Function.

The mitochondrial cascade hypothesis of dementia assumes mitochondrial dysfunction leading to reduced energy supply, impaired neuroplasticity, and finally cell death as one major pathomechanism underlying the continuum from brain aging over mild cognitive impairment to initial and advanced late onset Alzheimer's disease. Accordingly, improving mitochondrial function has become an important strategy to treat the early stages of this continuum. The metabolic enhancer piracetam has been proposed as possible prototype for those compounds by increasing impaired mitochondrial function and related aspects like mechanisms of neuroplasticity. We here report that piracetam at therapeutically relevant concentrations improves neuritogenesis in the human cell line SH-SY5Y over conditions mirroring the whole spectrum of age-associated cognitive decline. These effects go parallel with improvement of impaired mitochondrial dynamics shifting back fission and fusion balance to the energetically more favorable fusion site. Impaired fission and fusion balance can also be induced by a reduction of the mitochondrial permeability transition pore (mPTP) function as atractyloside which indicates the mPTP has similar effects on mitochondrial dynamics. These changes are also reduced by piracetam. These findings suggest the mPTP as an important target for the beneficial effects of piracetam on mitochondrial function.

Beers-Criteria: Translation of the recent update. / Aktuelles Update der Beers-Kriterien Deutsche Übersetzung und Anpassung an den deutschen Arzneimittelmarkt.

The Beers criteria are an important instrument to improve medication safety in geriatrics. In 2015, the American Geriatrics Society (AGS) updated the Beers criteria and extended the list regarding important aspects. Our translation into German aims to simplify the application in German health care and to improve medication safety. The list was adapted to the German health care market to ensure its suitability for daily clinical use. The updated Beers lists is extended regarding clinical relevant drug-drug interactions and advice for dose titration in patients with renal insufficiency. Thereby, we hope that the updated Beers criteria will help to optimize geriatric pharmacotherapy.

Selective Activation of a TRPC6 Ion Channel Over TRPC3 by Metalated Type-B Polycyclic Polyprenylated Acylphloroglucinols.

Selective modulation of TRPC6 ion channels is a promising therapeutic approach for neurodegenerative diseases and depression. A significant advancement showcases the selective activation of TRPC6 through metalated type-B PPAP, termed PPAP53. This success stems from PPAP53's 1,3-diketone motif facilitating metal coordination. PPAP53 is water-soluble and as potent as hyperforin, the gold standard in this field. In contrast to type-A, type-B PPAPs offer advantages such as gram-scale synthesis, easy derivatization, and long-term stability. Our investigations reveal PPAP53 selectively binding to the C-terminus of TRPC6. Although cryoelectron microscopy has resolved the majority of the TRPC6 structure, the binding site in the C-terminus remained unresolved. To address this issue, we employed state-of-the-art artificial-intelligence-based protein structure prediction algorithms to predict the missing region. Our computational results, validated against experimental data, indicate that PPAP53 binds to the 777LLKL780-region of the C-terminus, thus providing critical insights into the binding mechanism of PPAP53.

Mitochondrial Dysfunction as a Causative Factor in Alzheimer's Disease-Spectrum Disorders: Lymphocytes as a Window to the Brain.

Alzheimer's disease (AD) is the most common progressive neurodegenerative disease. Today, AD affects millions of people worldwide and the number of AD cases will further increase with longer life expectancy. The AD brain is marked by severe neurodegeneration, such as the loss of synapses and neurons, atrophy and depletion of neurotransmitter systems, especially in the hippocampus and cerebral cortex. Recent findings highlight the important role of mitochondrial dysfunction and increased oxidative stress in the pathophysiology of late-onset alzheimer's disease (LOAD). These alterations are not only observed in the brain of AD patients but also in the periphery. In this review, we discuss the potential role of elevated apoptosis, increased oxidative stress and mitochondrial dysfunction as peripheral markers for the detection of AD in blood cells e.g. lymphocytes. We evaluate recent findings regarding impaired mitochondrial function comprising mitochondrial respiration, reduced complex activities of the respiratory chain and altered Mitochondrial Membrane Potential (MMP) in lymphocytes as well as in neurons. Finally, we will question whether these mitochondrial parameters might be suitable as an early peripheral marker for the detection of LOAD but also for the transitional stage between normal aging and Dementia, "Mild Cognitive Impairment" (MCI).

Pharmacological basis of the anxiolytic and antidepressant properties of Silexan®, an essential oil from the flowers of lavender.

Silexan®, a proprietary essential oil manufactured by steam distillation from Lavandula angustifolia flowers showed pronounced anxiolytic effects in patients with subthreshold anxiety disorders and was also efficacious in patients with Generalized Anxiety disorder (GAD). Moreover, evidences for antidepressant-like properties of Silexan® have been observed in anxious patients suffering from comorbid depressive symptoms and in patients with mixed anxiety-depression disorder (ICD-10 F41.2). In accordance with the clinical data Silexan® is active in several behavioral models in rodents at rather low concentrations indicating potent anxiolytic and antidepressive properties. As possible mechanism of action a moderate inhibition of voltage dependent calcium channels (VDCC) has been found showing some similarities to the anxiolytic drug pregabalin. However, while pregabalin mainly inhibits P/Q-type channels by binding to a modulatory subunit, Silexan® moderately inhibits mainly T-type and N-type channels and to some extent P/Q-type channels. Unlike pregabalin Silexan® is free of hypnotic or sedative side effects and seems to be devoid of any abuse potential. With respect to its specific antidepressant like properties Silexan® improves several aspects of neuroplasticity which seems to be the common final pathway of all antidepressant drugs. As a potential mechanism of its effects on neuroplasticity an activation of the transcription factor CREB via activation of intracellular signaling kinases like PKA and MAPK has been found. Since the concentrations of Silexan® needed to inhibit VDCC function and to improve neuroplasticity are quite similar, the effects of Silexan® on PKA or MAPK could constitute a common intracellular signaling cascade leading to VDCC modulation as well as CREB activation and improved neuroplasticity.

Novel σ1 antagonists designed for tumor therapy: Structure - activity relationships of aminoethyl substituted cyclohexanes.

Depending on the substitution pattern and stereochemistry, 1,3-dioxanes 1 with an aminoethyl moiety in 4-position represent potent σ1 receptor antagonists. In order to increase the stability, a cyclohexane ring first replaced the acetalic 1, 3-dioxane ring of 1. A large set of aminoethyl substituted cyclohexane derivatives was prepared in a six-step synthesis. All enantiomers and diastereomers were separated by chiral HPLC at the stage of the primary alcohol 7, and their absolute configuration was determined by CD spectroscopy. Neither the relative nor the absolute configuration had a large impact on the σ1 affinity. The highest σ1 affinity was found for cis-configured benzylamines (1R,3S)-11 (Ki = 0.61 nM) and (1S,3R)-11 (Ki = 1.3 nM). Molecular dynamics simulations showed that binding of (1R,3S)-11 at the σ1 receptor is stabilized by the typical polar interaction of the protonated amino moiety with the carboxy group of E172 which is optimally oriented by an H-bond interaction with Y103. The lipophilic interaction of I124 with the N-substituent also contributes to the high σ1 affinity of the benzylamines. The antagonistic activity was determined in a Ca2+ influx assay in retinal ganglion cells. The enantiomeric cis-configured benzylamines (1R,3S)-11 and (1S,3R)-11 were able to inhibit the growth of DU145 cells, a highly aggressive human prostate tumor cell line. Moreover, cis-11 could also inhibit the growth of further human tumor cells expressing σ1 receptors. The experimentally determined logD7.4 value of 3.13 for (1R,3S)-11 is in a promising range regarding membrane penetration. After incubation with mouse liver microsomes and NADPH for 90 min, 43% of the parent (1R,3S)-11 remained unchanged, indicating intermediate metabolic stability. Altogether, nine metabolites including one glutathione adduct were detected by means of LC-MS analysis.