Transporter-mediated drug-drug interactions: regulatory guidelines, in vitro and in vivo methodologies and translation, special populations, and the blood-brain barrier.

This review, part of a special issue on drug-drug interactions (DDIs) spearheaded by the International Society for the Study of Xenobiotics (ISSX) New Investigators, explores the critical role of drug transporters in absorption, disposition, and clearance in the context of DDIs. Over the past two decades, significant advances have been made in understanding the clinical relevance of these transporters. Current knowledge on key uptake and efflux transporters that affect drug disposition and development is summarized. Regulatory guidelines from the FDA, EMA, and PMDA that inform the evaluation of potential transporter-mediated DDIs are discussed in detail. Methodologies for preclinical and clinical testing to assess potential DDIs are reviewed, with an emphasis on the utility of physiologically based pharmacokinetic (PBPK) modeling. This includes the application of relative abundance and expression factors to predict human pharmacokinetics (PK) using preclinical data, integrating the latest regulatory guidelines. Considerations for assessing transporter-mediated DDIs in special populations, including pediatric, hepatic, and renal impairment groups, are provided. Additionally, the impact of transporters at the blood-brain barrier (BBB) on the disposition of CNS-related drugs is explored. Enhancing the understanding of drug transporters and their role in drug disposition and toxicity can improve efficacy and reduce adverse effects. Continued research is essential to bridge remaining gaps in knowledge, particularly in comparison with cytochrome P450 (CYP) enzymes.

Integrated lymphoedema and tissue viability service: improving patient and wound outcomes.

This article will focus on the integration of tissue viability and lymphoedema services to improve outcomes for patients with leg ulceration. It will highlight why there is a need for lymphoedema specialist knowledge within the care of patients with leg ulceration and how the services are closely aligned. Lymphoedema can adversely affect wound healing and the article will provide case studies that highlight how developing a hybrid tissue viability and lymphoedema clinician or integration of the specialists can provide effective patient-centred care at reduced cost. The article offers potential strategies and suggestions on how to address inequalities in care and how to improve service provision.

Biallelic variants in TUBGCP6 result in microcephaly and chorioretinopathy 1: Report of four cases and a literature review.

Autosomal recessive microcephaly and chorioretinopathy-1 (MCCRP1) is a rare Mendelian disorder resulting from biallelic loss of function variants in Tubulin-Gamma Complex Associated Protein 6 (TUBGCP6, MIM#610053). Clinical features of this disorder include microcephaly, cognitive impairment, dysmorphic features, and variable ophthalmological anomalies including chorioretinopathy. Microcephaly can be recognized prenatally and visual impairment becomes evident during the first year of life. The clinical presentation resembles the findings in some acquired conditions such as congenital toxoplasmosis and cytomegalovirus infections; thus, it is important to recognize and diagnose this syndrome in view of its impact on patient health management and familial reproductive plans. To date, only seven molecularly confirmed patients from five unrelated families have been reported. We report an additional four unrelated patients with TUBGCP6 variants including one prenatal diagnosis and review the clinical phenotypes and genotypes of all the known cases. This report expands the molecular and phenotypic spectrum of TUBGCP6 and includes additional prenatal findings associated with MCCRP1.

In-vitro characterization of coding variants with predicted functional implications in the efflux transporter multidrug resistance protein 4 (MRP4, ABCC4).

MRP4 (gene ABCC4) is a polymorphic efflux transporter that has been implicated in drug-induced toxicity. We selected ten commonly observed MRP4 coding variants among Europeans for experimental characterization including nine variants predicted to be deleterious or functional (combined annotation-dependent depletion score >15). We assessed protein localization and activity by quantifying intracellular accumulation of two prototypic substrates, taurocholic acid (TCA) and estradiol 17-ß-glucuronide (E217ßG), in HEK293T over-expressing MRP4 wildtype or variant where cellular substrate loading was optimized through co-transfection with an uptake transporter. V458M, a novel variant not previously studied, and T1142M, showed reduced activity compared to MRP4 wildtype for E217ßG and TCA (P < 0.01), while L18I, G187W, K293E, and R531Q moderately increased activity in a substrate-dependent manner. Protein expression analysis indicated reduced cell surface expression for V458M (P < 0.01) but not T1142M compared to wildtype. Reduced activity may result from altered surface expression (V458M) or intrinsic activity as both variants map within the nucleotide-binding domains of MRP4. G187W showed a trend for reduced surface expression (P = 0.054) despite transport comparable or increased to wildtype suggesting enhanced intrinsic activity. Our findings suggest moderately altered MRP4 activity in six out of nine predicted functional variants with likely different mechanisms and substrate-specific effects. Cell-based studies using multiple known substrates are warranted to more accurately predict functional variants in this clinically important transporter.

Epigenetics in drug disposition & drug therapy: symposium report of the 24th North American meeting of the International Society for the Study of Xenobiotics (ISSX).

The 24th North American International Society for the Study of Xenobiotics (ISSX) meeting, held virtually from September 13 to 17, 2021, embraced the theme of "Broadening Our Horizons." This reinforces a key mission of ISSX: striving to share innovative science related to drug discovery and development. Session speakers and the ISSX New Investigators Group, which supports the scientific and professional development of student and early career ISSX members, elected to highlight the scientific content presented during the captivating session titled, "Epigenetics in Drug Disposition & Drug Therapy." The impact genetic variation has on drug response is well established; however, this session underscored the importance of investigating the role of epigenetics in drug disposition and drug discovery. Session speakers, Drs. Ning, McClay, and Lazarus, detailed mechanisms by which epigenetic players including long non-coding RNA (lncRNAs), microRNA (miRNAs), DNA methylation, and histone acetylation can alter the expression of genes involved in pharmacokinetics, pharmacodynamics, and toxicity. Dr. Ning detailed current knowledge about miRNAs and lncRNAs and the mechanisms by which they can affect the expression of drug metabolizing enzymes (DMEs) and nuclear receptors. Dr. Lazarus discussed the potential role of miRNAs on UDP-glucuronosyltransferase (UGT) expression and activity. Dr. McClay provided evidence that aging alters methylation and acetylation of DMEs in the liver, affecting gene expression and activity. These topics, compiled by the symposium organizers, presenters, and the ISSX New Investigators Group, are herein discussed, along with exciting future perspectives for epigenetics in drug disposition and drug discovery research.

Stakeholder identified research priorities for early intervention in psychosis.

BACKGROUND: Public resources to answer pertinent research questions about the impact of illness and treatment on people with mental health problems are limited. To target funds effectively and efficiently and maximize the health benefits to populations, prioritizing research areas is needed. Research agendas are generally driven by researcher and funder priorities, however, there is growing recognition of the need to include user-defined research priorities to make research more relevant, needs-based and efficient. OBJECTIVE: To gain consensus on top priorities for research into early intervention in psychosis through a robust, democratic process for prioritization enlisting the views of key stakeholders including users, carers and healthcare professionals. We also sought to determine which user-prioritized questions were supported by scientific evidence. DESIGN AND METHODS: We used a modified nominal group technique to gain consensus on unanswered questions that were obtained by survey and ranked at successive stages by a steering group comprising users, carer representatives and clinicians from relevant disciplines and stakeholder bodies. We checked each question posed in the survey was unanswered in research by reviewing evidence in five databases (Medline, Cinahl, PsychInfo, EMBASE and Cochrane Database). RESULTS: Two hundred and eighty-three questions were submitted by 207 people. After checking for relevance, reframing and examining for duplicates, 258 questions remained. We gained consensus on 10 priority questions; these largely represented themes around access and engagement, information needs before and after treatment acceptance, and the influence of service-user (SU) priorities and beliefs on treatment choices and effectiveness. A recovery SUtheme identified specific self-management questions and more globally, a need to fully identify factors that impact recovery. DISCUSSION AND CONCLUSIONS: Published research findings indicated that the priorities of service users, carers and healthcare professionals were aligned with researchers' and funders' priorities in some areas and misaligned in others providing vital opportunities to develop research agendas that more closely reflect users' needs. PATIENT AND PUBLIC CONTRIBUTION: Initial results were presented at stakeholder workshops which included service-users, carers, health professionals and researchers during a consensus workshop to prioritize research questions and allow the opportunity for feedback. Patient and public representatives formed part of the steering group and were consulted regularly during the research process.

Ill Fates and Heroic Feats: A Thematic Analysis of Elite Athleticism and Chronic Illness.

Far more than an individual endeavor, work is a collective enterprise, an ethic, in which individuals participate to fulfill needs of their surrounding social world. Specifically, sport professionals undergo strenuous physical labor to compete and garner public admiration. Yet, when chronic illness interferes with their performances, how are athletes expected to respond? Through a thematic analysis of newspaper discourses covering professional golfer Tim Simpson's mysterious illness over time, this study explores an athlete's persistence to compete despite his deteriorating health. Using a grounded theory approach, this study investigates the tensions between Simpson's efforts to maintain a "sport ethic" while instantaneously adhering to responsibilities expected of "healthy citizens". The analysis reveals Simpson's body as paradoxically the primary means for his athletic performance and the primary source of his declining health. Public discourses manage this paradox by diffusing disruptions provoked by Simpson's sudden illness and standardizing deviations observed of his actions to justify his work ethic. Drawing from these observations, the concluding discussion interrogates issues that surface when good health is framed as an achievement of rather than a basis for productive living.

Recent developments in in vitro and in vivo models for improved translation of preclinical pharmacokinetics and pharmacodynamics data.

Improved pharmacokinetics/pharmacodynamics (PK/PD) prediction in the early stages of drug development is essential to inform lead optimization strategies and reduce attrition rates. Recently, there have been significant advancements in the development of new in vitro and in vivo strategies to better characterize pharmacokinetic properties and efficacy of drug leads. Herein, we review advances in experimental and mathematical models for clearance predictions, advancements in developing novel tools to capture slowly metabolized drugs, in vivo model developments to capture human etiology for supporting drug development, limitations and gaps in these efforts, and a perspective on the future in the field.

Pharmacogenomics in the era of next generation sequencing - from byte to bedside.

Pharmacogenetic research has resulted in the identification of a multitude of genetic variants that impact drug response or toxicity. These polymorphisms are mostly common and have been included as actionable information in the labels of numerous drugs. In addition to common variants, recent advances in Next Generation Sequencing (NGS) technologies have resulted in the identification of a plethora of rare and population-specific pharmacogenetic variations with unclear functional consequences that are not accessible by conventional forward genetics strategies. In this review, we discuss how comprehensive sequencing information can be translated into personalized pharmacogenomic advice in the age of NGS. Specifically, we provide an update of the functional impacts of rare pharmacogenetic variability and how this information can be leveraged to improve pharmacogenetic guidance. Furthermore, we critically discuss the current status of implementation of pharmacogenetic testing across drug development and layers of care. We identify major gaps and provide perspectives on how these can be minimized to optimize the utilization of NGS data for personalized clinical decision-support.

Estimation of the burden of tinea capitis among children in Africa.

Tinea capitis is a common and endemic dermatophytosis among school age children in Africa. However, the true burden of the disease is unknown in Africa. We aimed to estimate the burden of tinea capitis among children <18 years of age in Africa. A systematic review was performed using Embase, MEDLINE and the Cochrane Library of Systematic Reviews to identify articles on tinea capitis among children in Africa published between January 1990 and October 2020. The United Nation's Population data (2019) were used to identify the number of children at risk of tinea capitis in each African country. Using the pooled prevalence, the country-specific and total burden of tinea capitis was calculated. Forty studies involving a total of 229,086 children from 17/54 African countries were identified and included in the analysis. The pooled prevalence of tinea capitis was 23% (95% CI, 17%-29%) mostly caused by Trichophyton species. With a population of 600 million (46%) children, the total number of cases of tinea capitis in Africa was estimated at 138.1 (95% CI, 102.0-174.1) million cases. Over 96% (132.6 million) cases occur in sub-Saharan Africa alone. Nigeria and Ethiopia with the highest population of children contributed 16.4% (n = 98.7 million) and 8.5% (n = 52.2 million) of cases, respectively. Majority of the participants were primary school children with a mean age of 10 years. Cases are mostly diagnosed clinically. There was a large discrepancy between the clinical and mycological diagnosis. About one in every five children in Africa has tinea capitis making it one of the most common childhood conditions in the region. A precise quantification of the burden of this neglected tropical disease is required to inform clinical and public health intervention strategies.

A Clinical Program for Transgender and Gender-Diverse Neurodiverse/Autistic Adolescents Developed through Community-Based Participatory Design.

Objective: A series of studies report elevated rates of autism and autistic characteristics among gender-diverse youth seeking gender services. Although youth with the co-occurrence present with complex care needs, existing studies have focused on co-occurrence rates. Further, clinical commentaries have emphasized provider-centered interpretations of clinical needs rather than key stakeholder-driven clinical approaches. This study aimed to employ community-based participatory research methodologies to develop a key stakeholder-driven clinical group program.Method: Autistic/neurodiverse gender-diverse (A/ND-GD) youth (N = 31), parents of A/ND-GD youth (N = 46), A/ND-GD self-advocates (N = 10), and expert clinical providers (N = 10) participated in a multi-stage community-based participatory procedure. Needs assessment data were collected repeatedly over time from A/ND-GD youth and their parents as the youth interacted with one another through ongoing clinical groups, the curriculum of which was developed progressively through the iterative needs assessments.Results: Separate adolescent and parent needs assessments revealed key priorities for youth (e.g., the importance of connecting with other A/ND-GD youth and the benefit of experiencing a range of gender-diverse role models to make gender exploration and/or gender affirmation more concrete) and parents (e.g., the need for A/ND-related supports for their children as well as provision of an A/ND-friendly environment that fosters exploration of a range of gender expressions/options). Integration and translation of youth and parent priorities resulted in 11 novel clinical techniques for this population.Conclusions: With generally high acceptability ratings for each component of the group program, this study presents a community-driven clinical model to support broad care needs and preferences of A/ND-GD adolescents.

Correction: Whole exome sequencing reveals HSPA1L as a genetic risk factor for spontaneous preterm birth.

[This corrects the article DOI: 10.1371/journal.pgen.1007394.].

Whole exome sequencing reveals HSPA1L as a genetic risk factor for spontaneous preterm birth.

Preterm birth is a leading cause of morbidity and mortality in infants. Genetic and environmental factors play a role in the susceptibility to preterm birth, but despite many investigations, the genetic basis for preterm birth remain largely unknown. Our objective was to identify rare, possibly damaging, nucleotide variants in mothers from families with recurrent spontaneous preterm births (SPTB). DNA samples from 17 Finnish mothers who delivered at least one infant preterm were subjected to whole exome sequencing. All mothers were of northern Finnish origin and were from seven multiplex families. Additional replication samples of European origin consisted of 93 Danish sister pairs (and two sister triads), all with a history of a preterm delivery. Rare exonic variants (frequency <1%) were analyzed to identify genes and pathways likely to affect SPTB susceptibility. We identified rare, possibly damaging, variants in genes that were common to multiple affected individuals. The glucocorticoid receptor signaling pathway was the most significant (p<1.7e-8) with genes containing these variants in a subgroup of ten Finnish mothers, each having had 2-4 SPTBs. This pathway was replicated among the Danish sister pairs. A gene in this pathway, heat shock protein family A (Hsp70) member 1 like (HSPA1L), contains two likely damaging missense alleles that were found in four different Finnish families. One of the variants (rs34620296) had a higher frequency in cases compared to controls (0.0025 vs. 0.0010, p = 0.002) in a large preterm birth genome-wide association study (GWAS) consisting of mothers of general European ancestry. Sister pairs in replication samples also shared rare, likely damaging HSPA1L variants. Furthermore, in silico analysis predicted an additional phosphorylation site generated by rs34620296 that could potentially affect chaperone activity or HSPA1L protein stability. Finally, in vitro functional experiment showed a link between HSPA1L activity and decidualization. In conclusion, rare, likely damaging, variants in HSPA1L were observed in multiple families with recurrent SPTB.

Genetic Associations with Gestational Duration and Spontaneous Preterm Birth.

BACKGROUND: Despite evidence that genetic factors contribute to the duration of gestation and the risk of preterm birth, robust associations with genetic variants have not been identified. We used large data sets that included the gestational duration to determine possible genetic associations. METHODS: We performed a genomewide association study in a discovery set of samples obtained from 43,568 women of European ancestry using gestational duration as a continuous trait and term or preterm (<37 weeks) birth as a dichotomous outcome. We used samples from three Nordic data sets (involving a total of 8643 women) to test for replication of genomic loci that had significant genomewide association (P<5.0×10-8) or an association with suggestive significance (P<1.0×10-6) in the discovery set. RESULTS: In the discovery and replication data sets, four loci (EBF1, EEFSEC, AGTR2, and WNT4) were significantly associated with gestational duration. Functional analysis showed that an implicated variant in WNT4 alters the binding of the estrogen receptor. The association between variants in ADCY5 and RAP2C and gestational duration had suggestive significance in the discovery set and significant evidence of association in the replication sets; these variants also showed genomewide significance in a joint analysis. Common variants in EBF1, EEFSEC, and AGTR2 showed association with preterm birth with genomewide significance. An analysis of mother-infant dyads suggested that these variants act at the level of the maternal genome. CONCLUSIONS: In this genomewide association study, we found that variants at the EBF1, EEFSEC, AGTR2, WNT4, ADCY5, and RAP2C loci were associated with gestational duration and variants at the EBF1, EEFSEC, and AGTR2 loci with preterm birth. Previously established roles of these genes in uterine development, maternal nutrition, and vascular control support their mechanistic involvement. (Funded by the March of Dimes and others.).

Advances in the study of drug metabolism - symposium report of the 12th Meeting of the International Society for the Study of Xenobiotics (ISSX).

The 12th International Society for the Study of Xenobiotics (ISSX) meeting, held in Portland, OR, USA from July 28 to 31, 2019, was attended by diverse members of the pharmaceutical sciences community. The ISSX New Investigators Group provides learning and professional growth opportunities for student and early career members of ISSX. To share meeting content with those who were unable to attend, the ISSX New Investigators herein elected to highlight the "Advances in the Study of Drug Metabolism" symposium, as it engaged attendees with diverse backgrounds. This session covered a wide range of current topics in drug metabolism research including predicting sites and routes of metabolism, metabolite identification, ligand docking, and medicinal and natural products chemistry, and highlighted approaches complemented by computational modeling. In silico tools have been increasingly applied in both academic and industrial settings, alongside traditional and evolving in vitro techniques, to strengthen and streamline pharmaceutical research. Approaches such as quantum mechanics simulations facilitate understanding of reaction energetics toward prediction of routes and sites of drug metabolism. Furthermore, in tandem with crystallographic and orthogonal wet lab techniques for structural validation of drug metabolizing enzymes, in silico models can aid understanding of substrate recognition by particular enzymes, identify metabolic soft spots and predict toxic metabolites for improved molecular design. Of note, integration of chemical synthesis and biosynthesis using natural products remains an important approach for identifying new chemical scaffolds in drug discovery. These subjects, compiled by the symposium organizers, presenters, and the ISSX New Investigators Group, are discussed in this review.

In Vitro Functional Characterization and in Silico Prediction of Rare Genetic Variation in the Bile Acid and Drug Transporter, Na+-Taurocholate Cotransporting Polypeptide (NTCP, SLC10A1).

Na+-taurocholate cotransporting polypeptide (NTCP, SLC10A1) is a key hepatic uptake transporter for bile acids and drugs and is the main functional receptor for hepatitis B and D viruses. Next-generation sequencing has revealed that a large number of rare SLC10A1 variants exist in the population. Little data exist regarding head-to-head comparison of in silico algorithms to predict functional effects of pharmacogenetic variants when compared to direct in vitro functional assessment. This study aimed at characterizing rare SLC10A1 variants in vitro and to assess the performance of seven in silico algorithms to predict the observed functional impacts. Thirty-five previously uncharacterized, rare, missense SLC10A1 variants were transiently expressed in human embryonic kidney 293 type T (HEK293T) cells. NCTP protein expression as well as uptake of substrates taurocholic acid (TCA) and rosuvastatin were assessed. Substrate-specific effects were observed for NTCP G191R, with TCA and rosuvastatin transport observed at 89 and 8% of wild-type (WT) uptake, respectively. Significantly reduced transport of TCA and rosuvastatin was observed for 19 variants (p < 0.05), with seven variants displaying decreased protein expression and marked reduction in transport of both substrates (0-13% of WT uptake, p < 0.0001). Performance of in silico algorithms to predict in vitro uptake, assessed using the area under the receiver operating characteristic curves (AUCROC), ranged from 0.69 to 0.97 and 0.72 to 0.84 for TCA and rosuvastatin uptake, respectively. In conclusion, we identified rare variants with significantly reduced NTCP expression and function. We demonstrated that no algorithm performed robustly enough to replace functional study in vitro, particularly given the broad substrate specificity of many pharmacogenes.

Probing Mental Health Invisibilities during a Global Pandemic.

With much attention devoted to physical health, what unseen consequences are emerging for mental health throughout the COVID-19 pandemic? The worldly disruption of COVID-19 casts rippling effects that penetrate the bodies and spirits of people experiencing this historical moment. Many of these ripples are subtle and difficult to trace. Peering into the waters muddied by COVID-19, we explore the subtle ripples, particularly the unseen mental health implications during this pandemic. In doing so, we issue questions as departure points for scholars and practitioners to consider for future research and practice in the changing landscape of our current world.

Pathogenic variants in AIMP1 cause pontocerebellar hypoplasia.

Aminoacyl-tRNA synthetase-interacting multifunctional protein 1 (AIMP1) is a non-catalytic component of the multi-tRNA synthetase complex which catalyzes the ligation of amino acids to the correct tRNAs. Pathogenic variants in several aminoacyl-tRNA synthetases genes have been linked to various neurological disorders, including leukodystrophies and pontocerebellar hypoplasias (PCH). To date, loss-of-function variants in AIMP1 have been associated with hypomyelinating leukodystrophy-3 (MIM 260600). Here, we report a novel frameshift AIMP1 homozygous variant (c.160delA,p.Lys54Asnfs) in a child with pontocerebellar hypoplasia and simplified gyral pattern, a phenotype not been previously described with AIMP1 variants, thus expanding the phenotypic spectrum. AIMP1 should be included in diagnostic PCH gene panels.

Maternally inherited MAF variant associated with variable expression of Aymé-Gripp syndrome.

Aymé-Gripp syndrome is an intellectual disability syndrome characterized by autism spectrum disorder, cataracts, sensorineural hearing loss, skeletal involvement, seizures, cardiac anomalies, and distinctive facial features. The condition is caused by pathogenic variants in MAF. To date, less than 20 cases have been reported, the majority having de novo mutations. Here, we report a patient with classical features of Aymé-Gripp syndrome who inherited a MAF variant, c.206C>G (p.P69R), from a mother with normal intellectual function and normal hearing but with cataract and significant proteinuria. To the best of our knowledge, this is the first report of a patient who inherited a MAF causative variant from a parent with normal intellect. Although the syndrome typically has multiple malformations and intellectual disability, we suggest that a mild phenotype could exist. In addition, we suggest that the basal ganglia calcifications present in our proband could be a novel finding associated with MAF variants and offer further support for the relationship between these variants and late manifestations of renal disease.

Encountering the Unexpected: Revelations of Trust, Vulnerability, and Embodied Ways of Knowing.

Health communication scholars grapple with complex issues, many of which probe embodied sensibilities. This essay narrates a profound, unexpected moment that gives rise to notions of trust, vulnerability, and risks involved when conducting fieldwork. The author explains how embodied interactions bring forth latent constructs pertinent to health communication research, both for investigative practices and applied purposes. Furthermore, the author questions how symbolic acts demonstrated by research participants may illuminate powerful meanings yet simultaneously pose potential dangers for researchers.