Small molecule drug metabolite synthesis and identification: why, when and how?

The drug discovery and development process encompasses the interrogation of metabolites arising from the biotransformation of drugs. Here we look at why, when and how metabolites of small-molecule drugs are synthesised from the perspective of a specialist contract research organisation, with particular attention paid to projects for which regulatory oversight is relevant during this journey. To illustrate important aspects, we look at recent case studies, trends and learnings from our experience of making and identifying metabolites over the past ten years, along with with selected examples from the literature.

Generative and active engagement in learning neuroscience: A comparison of self-derivation and rephrase.

It is crucial to identify cognitive mechanisms that support knowledge growth. One such mechanism that is known to improve learning outcomes is generative processing: the construction of novel information beyond what is directly taught. In this study of college students, we investigate the learning outcomes associated with the generative process of self-derivation through integration, the integration of multiple related facts to generate novel information. We compare the effects of self-derivation versus an active rephrase control condition on retrieval, application, and organization of neuroscience classroom content. In the self-derivation condition, learners were prompted to generate inferences based on integration of two explicitly-taught facts. In the rephrase condition, learners were explicitly provided these inferences and asked to rephrase them. We found few overall differences between learning manipulation conditions. However, we found that, regardless of the learning manipulation condition to which learners were exposed, learners generated their own information on some trials. This generation predicted success on retrieval and application of learned information. Further, self-derivation, when successful, led to particularly high rates of retrieval when compared with active rephrase. These findings inform theory on generative processing, and demonstrate that self-derivation is a mechanism of knowledge growth that may be useful for retrieval.

Open Source Antibiotics: Simple Diarylimidazoles Are Potent against Methicillin-Resistant Staphylococcus aureus.

Antimicrobial resistance (AMR) is widely acknowledged as one of the most serious public health threats facing the world, yet the private sector finds it challenging to generate much-needed medicines. As an alternative discovery approach, a small array of diarylimidazoles was screened against the ESKAPE pathogens, and the results were made publicly available through the Open Source Antibiotics (OSA) consortium (https://github.com/opensourceantibiotics). Of the 18 compounds tested (at 32 µg/mL), 15 showed >90% growth inhibition activity against methicillin-resistant Staphylococcus aureus (MRSA) alone. In the subsequent hit-to-lead optimization of this chemotype, 147 new heterocyclic compounds containing the diarylimidazole and other core motifs were synthesized and tested against MRSA, and their structure-activity relationships were identified. While potent, these compounds have moderate to high intrinsic clearance and some associated toxicity. The best overall balance of parameters was found with OSA_975, a compound with good potency, good solubility, and reduced intrinsic clearance in rat hepatocytes. We have progressed toward the knowledge of the molecular target of these phenotypically active compounds, with proteomic techniques suggesting TGFBR1 is potentially involved in the mechanism of action. Further development of these compounds toward antimicrobial medicines is available to anyone under the licensing terms of the project.

Lineage-based scaling of germline intercellular bridges during oogenesis.

The size of subcellular structures must be tightly controlled to maintain normal cell function; this is especially important when cells are part of developing tissues or organs. Despite its importance, few studies have determined how the size of organelles or other structures is maintained during tissue growth, when cells are growing, dividing, and rearranging. The developing egg chamber is a powerful model in which to study the relative growth rates of subcellular structures. The egg chamber contains a cluster of sixteen germ cells, which are connected through intercellular bridges called ring canals. Ring canals are formed following incomplete cytokinesis after each of four germ cell divisions. As the egg chamber grows, the nurse cells and the ring canals that connect them increase in size. Here, we demonstrate that ring canal size scaling is related to their lineage; the largest, "first born" ring canals grow at a relatively slower rate than ring canals derived from subsequent mitotic divisions. This lineage-based scaling relationship is maintained even if directed transport is reduced, ring canal size is altered, or if the germ cells go through an additional mitotic division. Further, we propose that changes in ring canal scaling could provide a mechanism to alter egg size.

ADHD and Substance Use Disorders in Young People: Considerations for Evaluation, Diagnosis, and Pharmacotherapy.

Co-occurring ADHD and substance use disorder (SUD) is a common clinical presentation associated with significant impairment requiring careful evaluation, diagnosis, and treatment. Treatment with medication, along with cognitive behavioral therapy, is generally regarded as effective in addressing symptoms and impairments associated with both disorders. Options for pharmacotherapy include stimulant and nonstimulant therapies administered with careful monitoring of dosage and compliance to optimize efficacy. In high-risk groups such as college students and/or those with SUD, prescribers should address risks of stimulant misuse and diversion through patient and family education, medication monitoring, and other risk-reducing practices.

Prompt-facilitated learning: The development of unprompted memory integration and subsequent self-derivation.

What are the boundaries that limit expansion of semantic knowledge across development? One striking contender is the necessity of a prompt to integrate and self-generate new information. The present research was an investigation of 7-9-year-olds' and 18-22-year-olds' prompted versus unprompted memory integration and subsequent self-derivation of new knowledge. Children and adults (Experiments 1 and 2, respectively) were exposed to sets of novel, true facts that could be integrated to self-derive new knowledge. On some trials they were prompted to integrate and self-derive and on others they were not. Both children and young adults capitalized more effectively on prompted opportunities to self-derive compared with unprompted opportunities, and the mechanism of this difference in performance likely underlies memory integration. Thus, the current work illustrates the importance of the conditions under which memory integration occurs, regardless of age. Results also offer evidence consistent with developmental change in unprompted integration and self-derivation performance, such that children and adults may engage the process of self-derivation differently. This work is particularly important in highlighting the necessity of appropriate scaffolding to foster successful learning opportunities and understanding the conditions under which semantic knowledge is accumulated.

Biotransformation: Impact and Application of Metabolism in Drug Discovery.

Biotransformation has a huge impact on the efficacy and safety of drugs. Ultimately the effects of metabolism can be the lynchpin in the discovery and development cycle of a new drug. This article discusses the impact and application of biotransformation of drugs by mammalian systems, microorganisms, and recombinant enzymes, covering active and reactive metabolites, the impact of the gut microbiome on metabolism, and how insights gained from biotransformation studies can influence drug design from the combined perspectives of a CRO specializing in a range of biotransformation techniques and pharma biotransformation scientists. We include a commentary on how biology-driven approaches can complement medicinal chemistry strategies in drug optimization and the in vitro and surrogate systems available to explore and exploit biotransformation.

Invasion, isolation and evolution shape population genetic structure in Campanula rotundifolia.

The distribution and genetic structure of most plant species in Britain and Ireland bear the imprint of the last ice age. These patterns were largely shaped by random processes during recolonization but, in angiosperms, whole-genome duplication may also have been important. We investigate the distribution of cytotypes of Campanula rotundifolia, considering DNA variation, postglacial colonization, environmental partitioning and reproductive barriers. Cytotypes and genome size variation from across the species' range were determined by flow cytometry and genetic variation was assessed using cpDNA markers. A common garden study examined growth and flowering phenology of tetraploid, pentaploid and hexaploid cytotypes and simulated a contact zone for investigation of reproductive barriers. Irish populations were entirely hexaploid. In Britain, hexaploids occurred mostly in western coastal populations which were allopatric with tetraploids, and in occasional sympatric inland populations. Chloroplast markers resolved distinct genetic groups, related to cytotype and geographically segregated; allopatric hexaploids were distinct from tetraploids, whereas sympatric hexaploids were not. Genome downsizing occurred between cytotypes. Progeny of open-pollinated clones from the contact zone showed that maternal tetraploids rarely produced progeny of other cytotypes, whereas the progeny of maternal hexaploids varied, with frequent pentaploids and aneuploids. The presence of distinctive hexaploid chloroplast types in Ireland, Scottish islands and western mainland Britain indicates that its establishment preceded separation of these land masses by sea-level rise c. 16 000 years BP. This group did not originate from British tetraploids and probably diverged before postglacial invasion from mainland Europe. The combination of cytotype, molecular, contact zone and common garden data shows an overall pattern reflecting postglacial colonization events, now maintained by geographic separation, together with more recent occasional local in situ polyploidisation. Reproductive barriers favour the persistence of the tetraploid to the detriment of the hexaploid.

Integrating Genomics into Healthcare: A Global Responsibility.

Genomic sequencing is rapidly transitioning into clinical practice, and implementation into healthcare systems has been supported by substantial government investment, totaling over US$4 billion, in at least 14 countries. These national genomic-medicine initiatives are driving transformative change under real-life conditions while simultaneously addressing barriers to implementation and gathering evidence for wider adoption. We review the diversity of approaches and current progress made by national genomic-medicine initiatives in the UK, France, Australia, and US and provide a roadmap for sharing strategies, standards, and data internationally to accelerate implementation.

Weight Loss Strategies Used by Army Reserve Officer Training Corps Cadets: Implication for Student Health and Wellness Services.

Background: Maintaining a healthy weight is a military requirement for the Reserve Officer Training Corps (ROTC) cadets. Male and female soldiers often have different approaches to maintaining a healthy weight and mobile health (m-health) tools can be harnessed and tailored to the needs of individual cadets. Objectives: This study examined gender differences in technology use, weight loss strategies, information needed to maintain a healthy weight, and willingness to participate in m-health research and programs. Materials and Methods: A self-administered survey was completed by 404 cadets from ROTC programs in Florida in 2017. Results: Most owned smartphones and used them as their primary internet access. Women had significantly lower body mass index than men (p = 0.037). Most used healthy weight loss strategies, including increasing physical activity, reducing sweets, and reducing fried foods. Women were more likely than men to reduce fried foods (p < 0.0003) and sweets (p = 0.020). Most reported a willingness to participate in m-health weight management research and programs, with women more willing to do so (p = 0.038). Most were willing to participate in m-health programs that used text messages, food/activity/sleep apps, smart watches/fitness trackers, and stress management/anxiety apps. Women were more willing to participate in programs that used apps for stress/anxiety management (p = 0.004) and to track food/activity/sleep (p < 0.0001). Most needed information on eating healthy on a budget and eating healthy on-the-run. Conclusions: Opportunities exist for college health and wellness professionals to use a variety of m-health tools and apps to promote general health and wellness and to help cadets achieve and maintain a healthy weight.

Sharing and reuse of individual participant data from clinical trials: principles and recommendations.

OBJECTIVES: We examined major issues associated with sharing of individual clinical trial data and developed a consensus document on providing access to individual participant data from clinical trials, using a broad interdisciplinary approach. DESIGN AND METHODS: This was a consensus-building process among the members of a multistakeholder task force, involving a wide range of experts (researchers, patient representatives, methodologists, information technology experts, and representatives from funders, infrastructures and standards development organisations). An independent facilitator supported the process using the nominal group technique. The consensus was reached in a series of three workshops held over 1 year, supported by exchange of documents and teleconferences within focused subgroups when needed. This work was set within the Horizon 2020-funded project CORBEL (Coordinated Research Infrastructures Building Enduring Life-science Services) and coordinated by the European Clinical Research Infrastructure Network. Thus, the focus was on non-commercial trials and the perspective mainly European. OUTCOME: We developed principles and practical recommendations on how to share data from clinical trials. RESULTS: The task force reached consensus on 10 principles and 50 recommendations, representing the fundamental requirements of any framework used for the sharing of clinical trials data. The document covers the following main areas: making data sharing a reality (eg, cultural change, academic incentives, funding), consent for data sharing, protection of trial participants (eg, de-identification), data standards, rights, types and management of access (eg, data request and access models), data management and repositories, discoverability, and metadata. CONCLUSIONS: The adoption of the recommendations in this document would help to promote and support data sharing and reuse among researchers, adequately inform trial participants and protect their rights, and provide effective and efficient systems for preparing, storing and accessing data. The recommendations now need to be implemented and tested in practice. Further work needs to be done to integrate these proposals with those from other geographical areas and other academic domains.

From the Data on Many, Precision Medicine for "One": The Case for Widespread Genomic Data Sharing.

Within the decade, genome sequencing promises to become a routine part of healthcare around the globe. Many millions of genomes linked to health records will soon be available for researchers and clinicians to make use of to advance precision medicine. To realise the full impact of genomic medicine, genomic and clinical data must be interoperable across traditional geographic, jurisdictional, sectoral, and domain boundaries. Extremely large and diverse data sets are needed to provide a context for interpretation of genetic sequences. No single country or institution can achieve the necessary scale and diversity alone. Data must be shared within an internationally federated, learning health system.

Selective Inactivation of Fibroblast Growth Factor 22 (FGF22) in CA3 Pyramidal Neurons Impairs Local Synaptogenesis and Affective Behavior Without Affecting Dentate Neurogenesis.

Various growth factors regulate synapse development and neurogenesis, and are essential for brain function. Changes in growth factor signaling are implicated in many neuropsychiatric disorders such as depression, autism and epilepsy. We have previously identified that fibroblast growth factor 22 (FGF22) is critical for excitatory synapse formation in several brain regions including the hippocampus. Mice with a genetic deletion of FGF22 (FGF22 null mice) have fewer excitatory synapses in the hippocampus. We have further found that as a behavioral consequence, FGF22 null mice show a depression-like behavior phenotype such as increased passive stress-coping behavior and anhedonia, without any changes in motor, anxiety, or social cognitive tests, suggesting that FGF22 is specifically important for affective behavior. Thus, addressing the precise roles of FGF22 in the brain will help understand how synaptogenic growth factors regulate affective behavior. In the hippocampus, FGF22 is expressed mainly by CA3 pyramidal neurons, but also by a subset of dentate granule cells. We find that in addition to synapse formation, FGF22 also contributes to neurogenesis in the dentate gyrus: FGF22 null mice show decreased dentate neurogenesis. To understand the cell type-specific roles of FGF22, we generated and analyzed CA3-specific FGF22 knockout mice (FGF22-CA3KO). We show that FGF22-CA3KO mice have reduced excitatory synapses on CA3 pyramidal neurons, but do not show changes in dentate neurogenesis. Behaviorally, FGF22-CA3KO mice still show increased immobility and decreased latency to float in the forced swim test and decreased preference for sucrose in the sucrose preference test, which are suggestive of a depressive-like phenotype similar to FGF22 null mice. These results demonstrate that: (i) CA3-derived FGF22 serves as a target-derived excitatory synaptic organizer in CA3 in vivo; (ii) FGF22 plays important roles in dentate neurogenesis, but CA3-derived FGF22 is not involved in neurogenesis; and (iii) a depression-like phenotype can result from FGF22 inactivation selectively in CA3 pyramidal neurons. Our results link the role of CA3-derived FGF22 in synapse development, and not in neurogenesis, to affective behavior.

α/ß-Peptide Foldamers Targeting Intracellular Protein-Protein Interactions with Activity in Living Cells.

Peptides can be developed as effective antagonists of protein-protein interactions, but conventional peptides (i.e., oligomers of l-α-amino acids) suffer from significant limitations in vivo. Short half-lives due to rapid proteolytic degradation and an inability to cross cell membranes often preclude biological applications of peptides. Oligomers that contain both α- and ß-amino acid residues ("α/ß-peptides") manifest decreased susceptibility to proteolytic degradation, and when properly designed these unnatural oligomers can mimic the protein-recognition properties of analogous "α-peptides". This report documents an extension of the α/ß-peptide approach to target intracellular protein-protein interactions. Specifically, we have generated α/ß-peptides based on a "stapled" Bim BH3 α-peptide, which contains a hydrocarbon cross-link to enhance α-helix stability. We show that a stapled α/ß-peptide can structurally and functionally mimic the parent stapled α-peptide in its ability to enter certain types of cells and block protein-protein interactions associated with apoptotic signaling. However, the α/ß-peptide is nearly 100-fold more resistant to proteolysis than is the parent stapled α-peptide. These results show that backbone modification, a strategy that has received relatively little attention in terms of peptide engineering for biomedical applications, can be combined with more commonly deployed peripheral modifications such as side chain cross-linking to produce synergistic benefits.

Rangewide ploidy variation and evolution in Acacia senegal: a north-south divide?

Knowledge of rangewide variation in DNA content and ploidy level may be valuable in understanding the evolutionary history of a species. Recent studies of Acacia senegal report diploids and occasional tetraploids in the Sudano-Sahelian region of sub-Saharan Africa, but nothing is known about the overall extent of DNA ploidy variation within the species. In this study, we determine the DNA content and ploidy level of A. senegal across its native range, and explore whether the variation is related to its evolutionary and colonization history. We used propidium iodide flow cytometry (FCM) to estimate DNA content (2C value) and infer ploidy in 157 individuals from 54 populations on various tissues, using seeds, fresh leaves, dried leaves and twigs and herbarium specimens. The mean 2C DNA (pg ± s.d.) contents detected were 1.47 ± 0.09, 2.12 ± 0.02, 2.89 ± 0.12, and a single individual with 4.51 pg, corresponding to a polyploid series of diploid, triploid, tetraploid and hexaploid individuals. Diploids were confirmed by chromosome counts (2n = 2x = 26). Most populations (90.7 %) were of single ploidy level, while mixed ploidy populations (9.3 %) comprising mostly diploids (2x+3x, 2x+4x and 2x+6x) were restricted to the Sudano-Sahelian and Indian subcontinent regions, its northern range. The species is predominantly diploid, and no mixed ploidy populations were detected in east and southern Africa, its southern range. The geographic pattern of ploidy variation in conjunction with existing phylogeographic and phylogenetic data of the species suggests that polyploids have occurred multiple times in its evolutionary and recent colonization history, including contemporary ecological timescales. The successful use of external tissues of dried twigs in FCM is new, and presents the opportunity to study numerous other dryland woody species.

Investigating the role of BDNF and CCK system genes in suicidality in a familial bipolar cohort.

BACKGROUND: Suicidal behaviour is a phenotype widely associated with psychiatric disorders such as major depressive disorder and bipolar disorder. However, recent evidence indicates that part of the heritability of suicidal behaviour is independent of the heritability of individual psychiatric disorders. This allows investigation into genetic risk factors for suicidal behaviour within a disorder using a candidate gene association approach. METHODS: We used family-based association testing in a cohort of 130 multiplex bipolar pedigrees, comprising 795 individuals, to look for associations between suicidal behaviour and 32 single nucleotide polymorphisms (SNPs) from across the genes brain-derived neurotrophic factor (BDNF), cholecystokinin (CCK) and the cholecystokinin beta-receptor (CCKBR). RESULTS: We found associations (p≤0.05) between suicide attempt and 12 SNPs of CCKBR and five SNPs of BDNF. After correction for multiple testing, seven SNPs of CCKBR remained significantly associated. No association was found between CCK and suicidal behaviour. LIMITATIONS: The study relied on retrospective self-reporting by individuals to determine phenotype, and the sample size was relatively small. CONCLUSIONS: The results of the study support the hypothesis that some CCKBR polymorphisms may contribute to an underlying predisposition towards suicidal behaviour in bipolar disorder.

Cholecystokinin system genes: associations with panic and other psychiatric disorders.

BACKGROUND: The cholecystokinin (CCK) system has long been hypothesised to have a role in the pathogenesis of panic attacks. Previous research into genetic variation within the CCK gene and the genes for its two receptors, CCKAR and CCKBR, has produced mixed results. We aimed to clarify this association by investigating multiple variants within each gene and multiple phenotypes associated with panic that may have confounded the previous studies' findings. METHODS: Variants were selected for the three genes based on HapMap CEU data. Individuals from a family based cohort (n=563) were genotyped for these variations and this data was analysed in FBAT. RESULTS: CCKBR showed the strongest association with panic, having multiple variants with p<0.05 (lowest: p=0.007). In CCKAR, some evidence was found for an association with panic, though further analysis suggested that the co-morbid bipolar-panic phenotype was most strongly associated. No variants in CCK were associated with panic but broader anxiety phenotypes did show associations. LIMITATIONS: Small sample size prevented thorough investigation of phenotypes, particularly pure disorders, and no correction was made for the multiple phenotypes analysed. CONCLUSIONS: Our findings support the involvement of variation in the CCK system, particularly CCKBR, in the pathogenesis of panic. Our data suggest that variation in CCK may be involved in several anxiety phenotypes and CCKAR may be involved in the development of panic co-morbid with bipolar disorder. These latter findings require further investigation and highlight the importance of clearly defined phenotypes when investigating psychiatric genetics.

Angiotensin-I-converting enzyme and prolyl endopeptidase inhibitory peptides from natural sources with a focus on marine processing by-products.

Like many natural resource-based processing industries, the seafood processing sector gives rise to a significant volume of organic waste. Environmental issues, economic concerns and legal restrictions regarding the disposal of processing wastes have led to increased research in the discovery of alternative value-added products, such as bioactive peptides from these waste streams. Bioactive peptides have various physiological functionalities in the human body following consumption and these include antihypertensive, antiamnesiac, mineral-binding, immunodulatory, antioxidative and antithrombotic activities. The search for bioactive peptides from a variety of different sources has become a major area of research with potential for the functional foods sector. The isolation of bioactive peptides typically involves the hydrolysis of the protein of choice with different proteolytic enzymes, alone or in combination with Generally Recognised as Safe (GRAS) micro-organisms. This review details information on angiotensin I-converting enzyme (ACE) and prolyl endopeptidase (PEP) inhibitors derived from natural, marine and marine processing waste streams and their potential for use as high-value added bioactive peptides.