Faculty Bibliography

The locus coeruleus (LC) plays important roles in sleep/wake regulation and cognitive functions. LC neurons may be particularly sensitive to neural injury and serve as an early site of accumulation pathological tau in Alzheimer's disease. Obstructive sleep apnea (OSA) creates both chronic intermittent hypoxia and sleep fragmentation as potential insults to differentially sensitive neural populations including the locus coeruleus (LC). Using high field 7T imaging in cognitively normal older adults, we demonstrate that time spent with an oxygen saturation below 90% (T90), a measure of OSA's hypoxic burden, inversely correlates with LC structural integrity and explains significant variance in LC structural integrity after controlling for age, sex, and BMI. In contrast, other sleep variables such as the apnea-hypopnea index (AHI), total sleep time, and sleep efficiency did not contribute significant variance in LC structural integrity in this model. Thus, in the diagnosis of OSA, attention to hypoxic burden variables may be important in risk stratification for LC neural injury. This observation may inform future work determining whether mitigation of the hypoxemic burden from OSA can slow deterioration in LC integrity.

BACKGROUND:Familial dysautonomia (FD) is a hereditary neurodevelopmental disorder caused by aberrant splicing of the ELP1 gene, leading to a tissue-specific reduction in ELP1 protein expression. Preclinical models indicate that increasing ELP1 levels can mitigate disease manifestations. A blood-based ELP-1 protein assay may provide a reliable way to monitor gene target engagement. DESIGN AND METHODS/METHODS:Using a newly developed radioimmunoassay, we quantified ELP1 protein levels in peripheral blood samples collected from 59 homozygous FD patients carrying the IVS20 + 6T>C mutation and 66 heterozygous carriers. To assess the reproducibility of the measurement, replicate samples were collected in 43 participants. Longitudinal variability was evaluated in 22 participants who underwent repeat sampling 1 year later. RESULTS: = 0.827, p < 0.001). An ELP1 threshold of 492 pg/mL yielded a sensitivity of 80.2% (CI of 70.6 to 87.2%) and a specificity of 98.2% (95% CI of 90%-99%) with a positive likelihood ratio of 46.5, indicating that individuals with FD were over 46 times more likely to have ELP1 levels below this threshold compared to non-affected carriers. CONCLUSION/CONCLUSIONS:Blood ELP1 levels are robust and reproducible, with concentrations below 492 pg/mL strongly indicative of disease. Moreover, given their longitudinal stability, ELP1 can serve as a marker of target engagement to evaluate the efficacy of gene-targeted therapies aimed at correcting ELP1 gene splicing and protein production.

Aging is often accompanied by a decline in mobility across species, which can be improved by aerobic exercise, even in individuals with Parkinson's disease. We showed previously that 30 days of voluntary wheel-running exercise in young male mice leads to enhanced release of the motor-system transmitter, dopamine (DA), in ex vivo corticostriatal slices. Here we tested whether voluntary exercise also increases DA release in aging (12 months old) mice of both sexes, and whether this is associated with improved motor performance. Mice were allowed unlimited access to a rotating (runners) or a locked (controls) wheel for 30 days. Motor behavior was then assessed, and electrically evoked DA release was quantified in slices from these animals using fast-scan cyclic voltammetry. Although daily running distance for females was nearly twice that of males, runners of both sexes showed comparable increases in evoked DA release in dorsolateral striatum and in nucleus accumbens core and shell compared to age- and sex-matched controls. Runners of both sexes showed an increase in locomotion velocity and improved motor coordination. Thus, voluntary exercise boosts striatal DA release and improves motor performance in aging mice, providing new insights into the benefits of exercise in aging humans.

Prostate MRI has transformed lesion detection and risk stratification in prostate cancer, but its impact is constrained by the high cost of the exam, variability in interpretation, and limited scalability. False negatives, false positives, and moderate inter-reader agreement undermine reliability, while long acquisition times restrict throughput. Artificial intelligence (AI) offers potential solutions to address many of the limitations of prostate MRI in the clinical management pathway. Machine learning-based triage can refine patient selection to optimize resources. Deep learning reconstruction enables accelerated acquisition while preserving diagnostic quality, with multiple FDA-cleared products now in clinical use. Ongoing development of automated quality assessment and artifact correction aims to improve reliability by reducing nondiagnostic exams. In image interpretation, AI models for lesion detection and clinically significant prostate cancer prediction achieve performance comparable to radiologists, and the PI-CAI international reader study has provided the strongest evidence to date of non-inferiority at scale. More recent work extends MRI-derived features into prognostic modeling of recurrence, metastasis, and functional outcomes. This review synthesizes progress across five domains-triage, accelerated acquisition and reconstruction, image quality assurance, diagnosis, and prognosis-highlighting the level of evidence, validation status, and barriers to adoption. While acquisition and reconstruction are furthest along, with FDA-cleared tools and prospective evaluations, triage, quality control, and prognosis remain earlier in development. Ensuring equitable performance across populations, incorporating uncertainty estimation, and conducting prospective workflow trials will be essential to move from promising prototypes to routine practice. Ultimately, AI could accelerate the adoption of prostate MRI toward a scalable platform for earlier detection and population-level prostate cancer management. EVIDENCE LEVEL: N/A TECHNICAL EFFICACY: 3.

Seventy % of mammals copulate using repeated pelvic thrusting, while the transfer of sperm requires just a single intromission. Why did thrusting evolve to be the dominant form of sexual intercourse? In this study, we investigate how the rate of sexual pelvic thrusting changes with body size. By analyzing films of copulating mammals, from mice Mus musculus to elephants Elephantidae, we find that bigger animals thrust slower. The rate of pelvic thrusting decreases from 6 Hz for the pocket mouse Pergonathus to 1.3-1.8 Hz for humans to an absence of thrusting for the rhino Rhinocerotidae and elephant Elephantidae families. To understand this dependence on body size, we consider the spring-like behavior of the legs, which is associated with the elasticity of the body's muscles, tendons, and ligaments. For both running and thrusting, a maximum amplitude and great energy savings can be achieved if the system is oscillated at its resonant or natural frequency. Resonant frequencies, as measured through previous studies of running in dogs Canis familiaris and horses Equus ferus caballus, show good agreement with sexual thrusting frequencies. Running and sexual thrusting have nothing in common from a behavioral perspective, but from a physical perspective, they are both constrained by the same musculoskeletal systems, and both take advantage of resonance. Our findings may provide improved treatments for human sexual dysfunction as well as improving breeding strategies for domestic mammals.

Individuals with Alzheimer's disease (AD) have an increased incidence of seizures, which worsen cognitive decline. Using a transgenic mouse model of AD neuropathology that exhibits spontaneous seizures, we previously found that seizure activity stimulates and accelerates depletion of the hippocampal neural stem cell (NSC) pool, which was associated with deficits in neurogenesis-dependent spatial discrimination. However, the precise molecular mechanisms that drive seizure-induced activation and depletion of NSCs are unclear. Here, using mice of both sexes, we performed RNA-sequencing on the hippocampal dentate gyrus and identified differentially-expressed regulators of neurogenesis in the Wnt signaling pathway that regulates many aspects of cell proliferation. We found that the expression of sFRP3, a Wnt signaling inhibitor, is altered in a seizure-dependent manner and might be regulated by ΔFosB, a seizure-induced transcription factor. Increasing sFRP3 expression prevented NSC depletion and improved spatial discrimination, suggesting that the loss of sFRP3 might mediate seizure-driven impairment in cognition in AD model mice, and perhaps also in AD.Significance statement There is increased incidence of seizures in individuals with Alzheimer's disease (AD), but it is unclear how seizures contribute to cognitive decline. Here, we uncover a molecular mechanism by which seizures in AD induce expression of a long-lasting transcription factor in the hippocampal dentate gyrus that suppresses expression of sFRP3, an inhibitor of neural stem cell division, accelerating the depletion of a finite pool of neural stem cells and dysregulating adult hippocampal neurogenesis. We found that restoring sFRP3 expression prevents accelerated use and depletion of neural stem cells and improves performance in an adult neurogenesis-dependent cognitive task. Our findings have implications for AD, epilepsy, and other neurological disorders that are accompanied by seizures.

BACKGROUND:Urinary stone disease with a clear genetic cause, monogenic stone disease (MSD), is increasingly recognized as a significant proportion of the total population. When MSD is suspected, genetic testing provides a firm diagnosis that can alter management and treatment. Here we present testing results from a large cohort with suspected MSD. METHODS:Subjects with features suggestive of MSD (early onset, family history, frequent stones, nephrocalcinosis [NC], and/or CKD) were recruited by the Rare Kidney Stone Consortium and genotyped for up to 160 known or candidate MSD genes via a targeted massively parallel sequencing (tMPS) panel. We compared clinical and biochemical features between genetically resolved MSD and unresolved individuals. RESULTS:Of 426 families (657 patients) enrolled, 145 (34%) were resolved with identified disease associated variants in 22 known MSD genes. Ninety-nine families were biallelic, 37 monoallelic, and 2 digenic. An additional 21 of the 231 screened family members were resolved. Genes identified in 10 or more families were: AGXT, HOGA1, SLC34A3, CYP24A1, SLC3A1, and CLCN5. Compared to the unresolved group, MSD probands had a lower baseline and last visit estimated glomerular filtration rate (eGFR), earlier age of stone presentation, and more stone events and procedures/year of life. The resolve rate was higher in those less than 16 years, and NC was seen earlier in the MSD group. Overall, NC was a risk factor for lower eGFR. Among the specific disorders, primary hyperoxaluria patients had the earliest age of stone and NC diagnosis, and as expected, the highest urinary oxalate level. CONCLUSIONS:Our study emphasizes the value of selecting patients enriched for factors associated with MSD, and comprehensive genetic testing to achieve a high yield of genetic diagnoses. Significant clinical and biochemical characteristics of MSD patients were defined. A definitive MSD diagnosis facilitates individualized management and strategies to delay disease progression in probands and affected family members.

Gonadal hormones act throughout the brain and modulate psychiatric symptoms. Yet how hormones influence cognitive processes is unclear. Exogenous 17β-estradiol, the most potent estrogen, modulates dopamine in the nucleus accumbens core, which instantiates reward prediction errors (RPEs), the difference between received and expected reward. Here we show that following endogenous increases in 17β-estradiol, dopamine RPEs and behavioral sensitivity to previous rewards are enhanced, and nucleus accumbens core dopamine reuptake proteins are reduced. Rats adjusted how quickly they initiated trials in a task with varying reward states, balancing effort against expected rewards. Nucleus accumbens core dopamine reflected RPEs that influenced rats' initiation times. Higher 17β-estradiol predicted greater sensitivity to reward states and larger RPEs. Proteomics revealed reduced dopamine transporter expression following 17β-estradiol increases. Finally, knockdown of midbrain estrogen receptors suppressed sensitivity to reward states. Therefore, endogenous 17β-estradiol predicts dopamine reuptake and RPE signaling, and causally dictates the impact of previous rewards on behavior.

OBJECTIVE:To examine the associations of LRRK2 p.G2019S, GBA1 p.N409S, polygenic risk scores (PRS), and APOE E4 on PD penetrance, risk, and symptoms. METHODS:We conducted a US-based observational case-control study using data from the 23andMe Inc. and Fox Insight Genetic Substudy (FIGS) databases. The total cohort included 7,586,842 participants (n = 35,163 PD); 8791 LRRK2 p.G2019S carriers (565 with PD), 37,427 GBA1 p.N409S carriers (524 with PD), 244 dual LRRK2/GBA1 carriers (37 with PD), and 7.5 million noncarriers (34,037 with PD). PRS was calculated from the most recently published European genome-wide association study. Survival models estimated the cumulative incidence of PD. Logistic regressions estimated the relative odds of reporting motor and non-motor symptoms according to genetic exposure. RESULTS:By the age of 80 years, the cumulative incidence of PD was 30% for dual carriers, 24% for LRRK2 p.G2019S carriers, 4% for GBA1 p.N409S carriers, and 2% for noncarriers. Higher PRS was associated with increased penetrance of the variants and earlier time to PD diagnosis. GBA1 p.N409S PD was associated with the highest burden of non-motor symptoms, including REM sleep behavior disorder and cognitive/memory deficits, and LRRK2 p.G2019S with the lowest. APOE E4 dosage was associated with greater odds of reporting hallucinations and cognitive impairment in addition to carrier status. INTERPRETATION/CONCLUSIONS:Our findings support the use of genetic screening to enrich candidate selection for neuroprotective trials and better define outcome measures based on genetics.

BACKGROUND:Children born very preterm (VPT) are at high risk for attention problems. This study's purpose was to describe the Conners Kiddie Continuous Performance Test (K-CPT) assessment in children born VPT, including rates of clinically elevated scores, change over time, and associations between K-CPT scores and parent reported attention problems. METHODS:We studied 305 children from a multi-site study of children born VPT who completed at least one K-CPT assessment at age 5, 6, and/or 7 years. Parent-reported ADHD symptoms and diagnosis were also collected. We calculated K-CPT completion rates, mean scores, and rates of clinically elevated scores at each timepoint. Linear mixed models examined change over time in K-CPT scores. Correlations and generalized linear models investigated associations between K-CPT scores and ADHD symptoms and diagnoses. RESULTS:K-CPT scores showed expected age-related improvements from age 5-7, with significant intra- and inter-individual variability. Up to 1/3 of children had clinically elevated attention problems and another 1/3 had subclinical elevations. K-CPT scores were modestly correlated with parent-rated ADHD symptoms and children with a parent-reported ADHD diagnosis performed worse on nearly all K-CPT metrics. CONCLUSION/CONCLUSIONS:Performance-based measures like the K-CPT can be useful for research and clinical practice in VPT populations. IMPACT/CONCLUSIONS:Attention problems are a specific area of weakness for children born very preterm. Performance-based tests of attention have benefits and drawbacks compared to parent report measures yet are understudied in this population. We examined one performance-based measure (the Conners Kiddie Continuous Performance Test [K-CPT]) in 305 children born very preterm. We observed improving task scores from age 5-7 years with significant intra- and inter-individual variability, a sizable proportion of children with clinically and subclinically elevated scores, and modest associations between K-CPT scores and parent reported attention problems. The K-CPT could be a useful clinical and research tool in this population.