Faculty Bibliography

INTRODUCTION/UNASSIGNED:Individuals with Down syndrome (DS) exhibit neurological deficits throughout life including the development of in Alzheimer's disease (AD) pathology and cognitive impairment. At the cellular level, dysregulation in neuronal gene expression is observed in postmortem human brain and mouse models of DS/AD. To date, RNA-sequencing (RNA-seq) analysis of hippocampal neuronal gene expression including the characterization of discrete circuit-based connectivity in DS remains a major knowledge gap. We postulate that spatially characterized hippocampal neurons display unique gene expression patterns due, in part, to dysfunction of the integrity of intrinsic circuitry. METHODS/UNASSIGNED:We combined laser capture microdissection to microisolate individual neuron populations with single population RNA-seq analysis to determine gene expression analysis of CA1 and CA3 pyramidal neurons and dentate gyrus granule cells located in the hippocampus, a region critical for learning, memory, and synaptic activity. RESULTS/UNASSIGNED:The hippocampus exhibits age-dependent neurodegeneration beginning at ~6 months of age in the Ts65Dn mouse model of DS/AD. Each population of excitatory hippocampal neurons exhibited unique gene expression alterations in Ts65Dn mice. Bioinformatic inquiry revealed unique vulnerabilities and differences with mechanistic implications coinciding with onset of degeneration in this model of DS/AD. CONCLUSIONS/UNASSIGNED:These cell-type specific vulnerabilities may underlie degenerative endophenotypes suggesting precision medicine targeting of individual populations of neurons for rational therapeutic development.

PURPOSE/OBJECTIVE:Stronger Together is a peer mentoring model that seeks to address the severe lack of mental health and psychosocial support for patients with cancer in many low- and middle-income countries (LMICs). This article presents the results of the Stronger Together pilot study among patients with breast and gynecologic cancer in Viet Nam (VN). METHODS:Eligible participants comprised women age 25 years or older with a diagnosis of breast or gynecologic cancers and receiving treatment at four participating hospitals. Participants were asked whether they wanted to proceed with usual care or be matched with a trained and supervised peer mentor (a cancer survivor). Surveys were administered at baseline (0) and 2, 4, and 6 months and assessed depression, anxiety, stress, mental health and physical health components of quality of life (QOL), self-efficacy, and social support. We computed and compared 2-, 4-, and 6-month changes in scores from baseline and conducted difference-in-difference analyses to estimate the intervention effect at 6 months. RESULTS:The sample size included N = 186 participants. Mentees (n = 91) exhibited improvements in depression, anxiety, stress, and mental health QOL across all time points, whereas usual care participants (n = 95) experienced these improvements at later periods (4 and 6 months). Compared with usual care participants, mentees reported greater improvements in depression at 2 and 4 months, mental health QOL at all time points, and self-efficacy and social support at 4 and 6 months. Greater improvements in stress were also seen in the breast cancer subsample. CONCLUSION/CONCLUSIONS:Stronger Together is a promising model to improve mental health and psychosocial outcomes among patients with breast and gynecologic cancer in VN and can help fill gaps in cancer peer support interventions in many LMICs.

Individuals with DS develop Alzheimer's disease (AD) neuropathology, including endosomal-lysosomal system abnormalities and degeneration of basal forebrain cholinergic neurons (BFCNs). We investigated whether maternal choline supplementation (MCS) affects early endosome pathology within BFCNs using the Ts65Dn mouse model of DS/AD. Ts65Dn and disomic (2N) offspring from dams administered MCS were analyzed for endosomal pathology at 3-4 months or 10-12 months. Morphometric analysis of early endosome phenotype was performed on individual BFCNs using Imaris. The effects of MCS on the endosomal interactome were interrogated by relative co-expression (RCE) analysis. MCS effectively reduced age- and genotype-associated increases in early endosome number in Ts65Dn and 2N offspring, and prevented increases in early endosome size in Ts65Dn offspring. RCE revealed a loss of interactome cooperativity among endosome genes in Ts65Dn offspring that was restored by MCS. These findings demonstrate MCS rescues early endosome pathology, a driver of septohippocampal circuit dysfunction. The genotype-independent benefits of MCS on endosomal phenotype indicate translational applicability as an early-life therapy for DS as well as other neurodevelopmental/neurodegenerative disorders involving endosomal pathology.

IMPORTANCE/UNASSIGNED:Increasing numbers of unaffected individuals could benefit from genetic evaluation for inherited cancer susceptibility. Automated conversational agents (ie, chatbots) are being developed for cancer genetics contexts; however, randomized comparisons with standard of care (SOC) are needed. OBJECTIVE/UNASSIGNED:To examine whether chatbot and SOC approaches are equivalent in completion of pretest cancer genetic services and genetic testing. DESIGN, SETTING, AND PARTICIPANTS/UNASSIGNED:This equivalence trial (Broadening the Reach, Impact, and Delivery of Genetic Services [BRIDGE] randomized clinical trial) was conducted between August 15, 2020, and August 31, 2023, at 2 US health care systems (University of Utah Health and NYU Langone Health). Participants were aged 25 to 60 years, had had a primary care visit in the previous 3 years, were eligible for cancer genetic evaluation, were English or Spanish speaking, had no prior cancer diagnosis other than nonmelanoma skin cancer, had no prior cancer genetic counseling or testing, and had an electronic patient portal account. INTERVENTION/UNASSIGNED:Participants were randomized 1:1 at the patient level to the study groups at each site. In the chatbot intervention group, patients were invited in a patient portal outreach message to complete a pretest genetics education chat. In the enhanced SOC control group, patients were invited to complete an SOC pretest appointment with a certified genetic counselor. MAIN OUTCOMES AND MEASURES/UNASSIGNED:Primary outcomes were completion of pretest cancer genetic services (ie, pretest genetics education chat or pretest genetic counseling appointment) and completion of genetic testing. Equivalence hypothesis testing was used to compare the study groups. RESULTS/UNASSIGNED:This study included 3073 patients (1554 in the chatbot group and 1519 in the enhanced SOC control group). Their mean (SD) age at outreach was 43.8 (9.9) years, and most (2233 of 3063 [72.9%]) were women. A total of 204 patients (7.3%) were Black, 317 (11.4%) were Latinx, and 2094 (75.0%) were White. The estimated percentage point difference for completion of pretest cancer genetic services between groups was 2.0 (95% CI, -1.1 to 5.0). The estimated percentage point difference for completion of genetic testing was -1.3 (95% CI, -3.7 to 1.1). Analyses suggested equivalence in the primary outcomes. CONCLUSIONS AND RELEVANCE/UNASSIGNED:The findings of the BRIDGE equivalence trial support the use of chatbot approaches to offer cancer genetic services. Chatbot tools can be a key component of sustainable and scalable population health management strategies to enhance access to cancer genetic services. TRIAL REGISTRATION/UNASSIGNED:ClinicalTrials.gov Identifier: NCT03985852.

We elucidated the molecular fingerprint of vulnerable excitatory neurons within select cortical lamina of individuals with Down syndrome (DS) for mechanistic understanding and therapeutic potential that also informs Alzheimer's disease (AD) pathophysiology. Frontal cortex (BA9) layer III (L3) and layer V (L5) pyramidal neurons were microisolated from postmortem human DS and age- and sex-matched controls (CTR) to interrogate differentially expressed genes (DEGs) and key biological pathways relevant to neurodegenerative programs. We identified > 2300 DEGs exhibiting convergent dysregulation of gene expression in both L3 and L5 pyramidal neurons in individuals with DS versus CTR subjects. DEGs included over 100 triplicated human chromosome 21 genes in L3 and L5 neurons, demonstrating a trisomic neuronal karyotype in both laminae. In addition, thousands of other DEGs were identified, indicating gene dysregulation is not limited to trisomic genes in the aged DS brain, which we postulate is relevant to AD pathobiology. Convergent L3 and L5 DEGs highlighted pertinent biological pathways and identified key pathway-associated targets likely underlying corticocortical neurodegeneration and related cognitive decline in individuals with DS. Select key DEGs were interrogated as potential hub genes driving dysregulation, namely the triplicated DEGs amyloid precursor protein (APP) and superoxide dismutase 1 (SOD1), along with key signaling DEGs including mitogen activated protein kinase 1 and 3 (MAPK1, MAPK3) and calcium calmodulin dependent protein kinase II alpha (CAMK2A), among others. Hub DEGs determined from multiple pathway analyses identified potential therapeutic candidates for amelioration of cortical neuron dysfunction and cognitive decline in DS with translational relevance to AD.

Although a considerable literature documents associations between early mother-infant interaction and cognitive outcomes in the first years of life, few studies examine the contributions of contingently coordinated mother-infant interaction to infant cognitive development. This study examined associations between the temporal dynamics of the contingent coordination of mother-infant face-to-face interaction at 4 months and cognitive performance on the Bayley Scales of Infant Development at age one year in a sample of (N = 100) Latina mother-infant pairs. Split-screen videotaped interactions were coded on a one second time base for the communication modalities of infant and mother gaze and facial affect, infant vocal affect, and mother touch. Multi-level time-series models evaluated self- and interactive contingent processes in these modalities and revealed 4-month patterns of interaction associated with higher one-year cognitive performance, not identified in prior studies. Infant and mother self-contingency, the moment-to-moment probability that the individual's prior behavior predicts the individual's future behavior, was the most robust measure associated with infant cognitive performance. Self-contingency findings showed that more varying infant behavior was optimal for higher infant cognitive performance, namely, greater modulation of negative affect; more stable maternal behavior was optimal for higher infant cognitive performance, namely, greater likelihood of sustaining positive facial affect. Although interactive contingency findings were sparse, they showed that, when mothers looked away, or dampened their faces to interest or mild negative facial affect, infants with higher 12-month cognitive performance were less likely to show negative vocal affect. We suggest that infant ability to modulate negative affect, and maternal ability to sustain positive affect, may be mutually reinforcing, together creating a dyadic climate that is associated with more optimal infant cognitive development.

BACKGROUND/UNASSIGNED:Individuals with Down syndrome (DS) have intellectual disability and develop Alzheimer's disease (AD) pathology during midlife, particularly in the hippocampal component of the medial temporal lobe memory circuit. However, molecular and cellular mechanisms underlying selective vulnerability of hippocampal CA1 neurons remains a major knowledge gap during DS/AD onset. This is compounded by evidence showing spatial (e.g., deep versus superficial) localization of pyramidal neurons (PNs) has profound effects on activity and innervation within the CA1 region. OBJECTIVE/UNASSIGNED:We investigated whether there is a spatial profiling difference in CA1 PNs in an aged female DS/AD mouse model. We posit dysfunction may be dependent on spatial localization and innervation patterns within discrete CA1 subfields. METHODS/UNASSIGNED:Laser capture microdissection was performed on trisomic CA1 PNs in an established mouse model of DS/AD compared to disomic controls, isolating the entire CA1 pyramidal neuron layer and sublayer microisolations of deep and superficial PNs from the distal CA1 (CA1a) region. RESULTS/UNASSIGNED:RNA sequencing and bioinformatic inquiry revealed dysregulation of CA1 PNs based on spatial location and innervation patterns. The entire CA1 region displayed the most differentially expressed genes (DEGs) in trisomic mice reflecting innate DS vulnerability, while trisomic CA1a deep PNs exhibited fewer but more physiologically relevant DEGs, as evidenced by bioinformatic inquiry. CONCLUSIONS/UNASSIGNED:CA1a deep neurons displayed numerous DEGs linked to cognitive functions whereas CA1a superficial neurons, with approximately equal numbers of DEGs, were not linked to pathways of dysregulation, suggesting the spatial location of vulnerable CA1 PNs plays an important role in circuit dissolution.

Down syndrome (DS) is a genetic disorder caused by triplication of human chromosome 21. In addition to intellectual disability, DS is defined by a premature aging phenotype and Alzheimer's disease (AD) neuropathology, including septohippocampal circuit vulnerability and degeneration of basal forebrain cholinergic neurons (BFCNs). The Ts65Dn mouse model recapitulates key aspects of DS/AD pathology, namely age-associated atrophy of BFCNs and cognitive decline in septohippocampal-dependent behavioral tasks. We investigated whether maternal choline supplementation (MCS), a well-tolerated treatment modality, protects vulnerable BFCNs from age- and genotype-associated degeneration in trisomic offspring. We also examined the effect of trisomy, and MCS, on GABAergic basal forebrain parvalbumin neurons (BFPNs), an unexplored neuronal population in this DS model. Unbiased stereological analyses of choline acetyltransferase (ChAT)-immunoreactive BFCNs and parvalbumin-immunoreactive BFPNs were conducted using confocal z-stacks of the medial septal nucleus and the vertical limb of the diagonal band (MSN/VDB) in Ts65Dn mice and disomic (2N) littermates at 3-4 and 10-12 months of age. MCS trisomic offspring displayed significant increases in ChAT-immunoreactive neuron number and density compared to unsupplemented counterparts, as well as increases in the area of the MSN/VDB occupied by ChAT-immunoreactive neuropil. MCS also rescued BFPN number and density in Ts65Dn offspring, a novel rescue of a non-cholinergic cell population. Furthermore, MCS prevented age-associated loss of BFCNs and MSN/VDB regional area in 2N offspring, indicating genotype-independent neuroprotective benefits. These findings demonstrate MCS provides neuroprotection of vulnerable BFCNs and non-cholinergic septohippocampal BFPNs, indicating this modality has translational value as an early life therapy for DS, as well as extending benefits to the aging population at large.

Separability (a Kronecker product) of a scatter matrix is one of favorable structures when multivariate heavy-tailed data are collected in a matrix form, due to its parsimonious representation. However, little attempt has been made to test separability beyond Gaussianity. In this paper, we present nonparametric separability tests that can be applied to a larger class of multivariate distributions not only including elliptical distributions but also generalized elliptical distributions and transelliptical distributions. The proposed test statistic exploits robustness of Tyler's M (or Kendall's tau) estimator and a likelihood function of a scaled variable. Since its distribution is hard to specify, we approximate the p-value using a permutation procedure, whose unbiasedness is obtained from the permutation invariance of multivariate paired data. Our simulation study demonstrates the efficacy of our method against other alternatives, and we apply it to rhesus monkey data and corpus callosum data.