Faculty Bibliography

Adeno-associated viruses (AAVs) are a commonly used tool in neuroscience to efficiently label, trace, and/or manipulate neuronal populations. Highly specific targeting can be achieved through recombinase-dependent AAVs in combination with transgenic rodent lines that express Cre-recombinase in specific cell types. Visualization of viral expression is typically achieved through fluorescent reporter proteins (e.g., GFP or mCherry) packaged within the AAV genome. Although nonamplified fluorescence is usually sufficient to observe viral expression, immunohistochemical amplification of the fluorescent reporter is routinely used to improve viral visualization. In the present study, Cre-dependent AAVs were injected into the neocortex of wild-type C57BL/6J mice. While we observed weak but consistent nonamplified off-target double inverted open reading frame (DIO) expression in C57BL/6J mice, antibody amplification of the GFP or mCherry reporter revealed notable Cre-independent viral expression. Off-target expression of DIO constructs in wild-type C57BL/6J mice occurred independent of vendor, AAV serotype, or promoter. We also evaluated whether Cre-independent expression had functional effects via designer receptors exclusively activated by designer drugs (DREADDs). The DREADD agonist C21 (compound 21) had no effect on contextual fear conditioning or c-Fos expression in DIO-hM3Dq-mCherry⁺ cells of C57BL/6J mice. Together, our results indicate that DIO constructs have off-target expression in wild-type subjects. Our findings are particularly important for the design of experiments featuring sensitive systems and/or quantitative measurements that could be negatively impacted by off-target expression.Significance StatementAdeno-associated viruses (AAVs) are widely used in neuroscience because of their safety and ease of use. Combined with specific promoters, Cre/loxP, and stereotaxic injections, highly specific targeting of cells and circuits within the brain can be achieved. In the present study, we injected Cre-dependent AAVs into wild-type C57BL/6J mice and found Cre-independent viral expression of AAVs encoding mCherry, GFP, or hM3Dq following immunohistochemical amplification of the fluorescent reporter protein. Importantly, we observed no functional effects of the Cre-independent expression in the hippocampus, as C21 (compound 21) had no detectable effect on double inverted open reading frame (DIO)-hM3Dq-mCherry-infected neurons in C57BL/6J mice. Given the widespread use of DIO recombinant AAVs by the neuroscience community, our data support careful consideration when using DIO constructs in control animals.

Background: Uganda has one of the highest HIV/AIDS rates and poor mental health services. Children and adolescents in communities with persistent poverty, disease (including HIV/AIDS), and violence, are more likely to suffer from chronic mental health problems. Combined, these characteristics negatively impact communities' response to HIV and mental health beginning with children, adolescents, and young adults. Yet, there is limited research capacity in child and adolescent mental health (CAMH), especially in the HIV/AIDS context in Uganda. Hence, this NIH-funded research training program aims to: (1) train three cohorts of early-career investigators at universities or research institutions in Uganda; (2) connect fellows with committed mentors; and (3) define key factors for successful mentorship and training of new investigators. Methods: CHILD-GRF is a multi-component program that engages selected young investigators in year-round activities for 3 years. Paired with mentors from Washington University in St. Louis and academic institutions in Uganda, fellows participate in a 6-week intensive summer training each year. Year 1 focuses on didactic learning and mentorship. In Year 2, fellows design and conduct their pilot study. Year 3 is devoted to presenting pilot study findings, manuscript preparation/ submission and extramural grant writing. Discussion: CHILD-GRF seeks to provide a solid foundation for the development and implementation of evidence-based HIV prevention and mental health interventions for youth and families impacted by HIV/AIDS. By producing a sustainable network of well-trained individuals in key research institutions, this program contributes to improving CAMH and HIV prevention efforts, both of which have public health implications.

Background: Despite evidence-based national guidelines for ADHD in the United Kingdom (UK), ADHD is under-identified, under-diagnosed, and under-treated. Many seeking help for ADHD face prejudice, long waiting lists, and patchy or unavailable services, and are turning to service-user support groups and/or private healthcare for help. Methods: A group of UK experts representing clinical and healthcare providers from public and private healthcare, academia, ADHD patient groups, educational, and occupational specialists, met to discuss shortfalls in ADHD service provision in the UK. Discussions explored causes of under-diagnosis, examined biases operating across referral, diagnosis and treatment, together with recommendations for resolving these matters. Results: Cultural and structural barriers operate at all levels of the healthcare system, resulting in a de-prioritization of ADHD. Services for ADHD are insufficient in many regions, and problems with service provision have intensified as a result of the response to the COVID-19 pandemic. Research has established a range of adverse outcomes of untreated ADHD, and associated long-term personal, social, health and economic costs are high. The consensus group called for training of professionals who come into contact with people with ADHD, increased funding, commissioning and monitoring to improve service provision, and streamlined communication between health services to support better outcomes for people with ADHD. Conclusions: Evidence-based national clinical guidelines for ADHD are not being met. People with ADHD should have access to healthcare free from discrimination, and in line with their legal rights. UK Governments and clinical and regulatory bodies must act urgently on this important public health issue.

Down syndrome (DS) is the primary genetic cause of intellectual disability (ID), which is due to the triplication of human chromosome 21 (HSA21). In addition to ID, HSA21 trisomy results in a number of neurological and physiological pathologies in individuals with DS, including progressive cognitive dysfunction and learning and memory deficits which worsen with age. Further exacerbating neurological dysfunction associated with DS is the concomitant basal forebrain cholinergic neuron (BFCN) degeneration and onset of Alzheimer's disease (AD) pathology in early mid-life. Recent single population RNA sequencing (RNA-seq) analysis in the Ts65Dn mouse model of DS, specifically the medial septal cholinergic neurons of the basal forebrain (BF), revealed the mitochondrial oxidative phosphorylation pathway was significantly impacted, with a large subset of genes within this pathway being downregulated. We further queried oxidative phosphorylation pathway dysregulation in Ts65Dn mice by examining genes and encoded proteins within brain regions comprising the basocortical system at the start of BFCN degeneration (6 months of age). In select Ts65Dn mice we demonstrate significant deficits in gene and/or encoded protein levels of Complex I-V of the mitochondrial oxidative phosphorylation pathway in the BF. In the frontal cortex (Fr Ctx) these complexes had concomitant alterations in select gene expression but not of the proteins queried from Complex I-V, suggesting that defects at this time point in the BF are more severe and occur prior to cortical dysfunction within the basocortical circuit. We propose dysregulation within mitochondrial oxidative phosphorylation complexes is an early marker of cognitive decline onset and specifically linked to BFCN degeneration that may propagate pathology throughout cortical memory and executive function circuits in DS and AD.

Cannabis (marijuana) has been known to humans for thousands of years but its neurophysiological effects were sparsely understood until recently. Preclinical and clinical studies in the past two decades have indisputably supported the clinical proposition that the endocannabinoid system plays an important role in the etiopathogeneses of many neuropsychiatric disorders, including mood and addictive disorders. In this review, we discuss the existing knowledge of exo- and endo-cannabinoids, and role of the endocannabinoid system in depressive and suicidal behavior. A dysfunction in this system, located in brain regions such as prefrontal cortex and limbic structures is implicated in mood regulation, impulsivity and decision-making, may increase the risk of negative mood and cognition as well as suicidality. The literature discussed here also suggests that the endocannabinoid system may be a viable target for treatments of these neuropsychiatric conditions.

As more young people feel safe to outwardly identify as transgender or gender expansive (TGE), meaning that their gender identity does not align with the sex they were assigned at birth, an increasing number of youth who identify as TGE seek gender-affirming medical care (GAMC). GAMC raises a number of ethical questions, such as the capacity of a minor to assent or consent, the role of parents or legal guardians in decisions about treatment, and implications for equitable access to care when differing parental or custodial viewpoints are present. These questions are further complicated by the difficulties in explaining the limits of long-term research in GAMC, with regard to the preservation of fertility, for example. We present two de-identified composite case studies to highlight dilemmas that may arise and offer recommendations to better support patient- and family-centered decision making for GAMC. These include employing a multidisciplinary shared decision-making approach, disentangling informed consent and assent from chronological age, developing a consistent approach to the assessment of decisional capacity, and developing age-appropriate informational materials.