Faculty Bibliography

Neurons accumulate somatic mutations with age, but how mutation processes vary among neuronal types remains unclear. Characterizing this variability may elucidate the role of genome integrity in brain function and disease and reveal determinants of mutation rates and patterns. Using high-fidelity duplex DNA sequencing, we profiled somatic mutations across the lifespan in human cerebellar Purkinje and granule neurons, which differ markedly in size and physiology. Surprisingly, they exhibited similar substitution rates, including rates of SBS5, the body's predominant mutational signature, whose mechanism is unknown. However, their substitution patterns and insertion/deletion rates and patterns differed, with transcription associated with these differences. In surviving granule neurons from five cerebellar ataxias, we detected only a small disease effect on mutation profiles. Our work indicates that neuronal types can differ in aging-related mutagenesis and that key features distinguishing Purkinje and granule neurons are unlikely, in these neurons, to be major determinants of SBS5 activity.

Applying advanced measurement technologies proactively in asymptomatic populations predictably yields false positives, as a consequence of Bayes’ Theorem. Yet the same Bayesian arithmetic suggests a remedy: adding context. Serial and multimodal measurements, integrated using context-aware AI that prioritizes within-person change over population norms, can reduce false positive rates while preserving sensitivity. We describe early illustrations from imaging and molecular diagnostics and discuss challenges including cost, anxiety, liability, and equity.

INTRODUCTION/BACKGROUND:We assessed plasma biomarkers for the diagnosis of early Alzheimer's disease (AD). METHODS: = 45). Plasma assays for amyloid beta (Aβ) 40, Aβ42, neurofilament light chain protein, glial fibrillary acidic protein, and phosphorylated tau181 levels were measured using single molecule array (Simoa) technology. Neuroinflammation and blood-brain barrier (BBB) biomarkers were measured using the Corplex cytokine 10-Plex kit and the angiogenesis 6-Plex kit, respectively. RESULTS:Biomarker levels were regressed by cognitive group, age, sex, race, and apolipoprotein E apoE ε4 status, yielded significant positive associations between age and numerous AD, neuroinflammation, cytokine, and BBB plasma markers. DISCUSSION/CONCLUSIONS:Linear regression analysis, adjusted for age, sex, race, and ApoE status, revealed significant differences between cognitive groups in levels of several plasma biomarkers and associations with age and sex. Neuroinflammation and BBB dysfunction showed significant positive associations with age across different stages of AD.

INTRODUCTION/BACKGROUND:Blood-brain barrier (BBB) dysfunction is an early feature of Alzheimer's disease (AD). Fibrinogen represents a sensitive marker of BBB leakage, but whether it modifies longitudinal tau progression in cognitively unimpaired (CU) individuals remains unknown. METHODS:CU older adults underwent clinical evaluation and cerebrospinal fluid (CSF) assessment of fibrinogen, Aβ42, total tau (tTau), phosphorylated tau 181 (pTau181), and YKL-40. Linear regression tested baseline associations. Linear mixed-effects models tested whether baseline fibrinogen predicted longitudinal pTau181 change. RESULTS:Among 169 CU participants with baseline fibrinogen, 87 had longitudinal pTau181 measurements (mean follow-up 2.5-years). Higher fibrinogen was associated with elevated YKL-40 (β = 0.28, 95% confidence interval [CI] [0.11, 0.45]) but not Aβ42, tTau, or pTau181 at baseline. Baseline fibrinogen modified longitudinal pTau181 trajectories (interaction β = 0.11, 95% CI [0.04, 0.19]), with only participants above the median showing significant pTau181 increases (β = 0.13, 95% CI [0.08, 0.18]). DISCUSSION/CONCLUSIONS:CSF fibrinogen associates cross-sectionally with glial inflammation and predicts accelerated tau accumulation in preclinical AD.

Pain is a pervasive and multifaceted condition that imposes a significant medical and economic burden worldwide. This burden is underscored by the urgent need for transformative, non-addictive opioid alternatives. Nanomedicine offers a promising avenue for addressing the many limitations associated with conventional pain treatments, such as off-target effects, poor bioavailability, and rapid clearance, while enabling advanced therapeutic approaches such as precise spatiotemporal control and robust delivery of biologics. In this review, we explore the convergence of nanomedicine and pain management. We examine current literature on pain and chronic pain physiology and provide collated pharmacological data on current therapeutic approaches as a reference for formulation development. Recent advancements in lipid-based, polymeric, and inorganic nanoscale drug delivery systems (NDDS) for pain are surveyed, along with their progress toward clinical translation. Strategies for enhancing the efficacy of NDDS for pain are discussed, including supramolecular depot localization methods, active and passive targeting, controlled release kinetics, and the incorporation of stimuli-responsive elements for triggered release. We identify knowledge and technical gaps limiting progression beyond sustained-release formulations toward designs exploiting pain-specific biology. Overall, this review provides a comprehensive overview of the state-of-the-art in nanomedicine-based approaches for pain management and provides a roadmap for future innovations.

Astrocyte loss occurs in various neurological conditions and can disrupt local tissue homeostasis. While astrocytes surrounding border-forming lesions adopt reactive states without restoring astrocyte networks, how astrocytes respond to spatially confined astrocyte loss remains poorly understood. Here we used longitudinal in vivo two-photon microscopy, combined with spatiotemporal transcriptional profiling, to examine astrocyte responses following focal aquaporin-4 antibody-mediated ablation in the somatosensory cortex of adult mouse brain, a model of astrocytopathy relevant to neuromyelitis optica spectrum disorder. Here we show that perilesional astrocytes undergo pronounced structural remodeling during lesion repopulation, characterized by cell proliferation, prolonged multinucleated astrocyte states, polarized process extension into the depleted area and gradual displacement of nuclei into previously unoccupied astrocyte territories. Spatial transcriptomics reveal an injury-associated molecular response that resolves as the astrocyte network is restored. Together, our findings delineate the spatiotemporal dynamics of astrocyte regeneration after astrocyte loss, extending current understanding of astroglial plasticity in the adult brain.

Synucleinopathies are a group of neurodegenerative disorders characterized by the accumulation of aggregated α-synuclein (α-syn), including Parkinson's disease, Dementia with Lewy Bodies, and Multiple System Atrophy. These diseases are marked by locomotor and non-motor impairments, as well as mitochondrial dysfunction and the loss of dopaminergic (DA) neurons. We have developed several anti-α-syn single-domain antibodies (sdAbs) and demonstrated the diagnostic imaging potential of two of them and the acute therapeutic benefit of one in clearing α-syn in a mouse model. However, whether these sdAbs can suppress α-syn-mediated neuronal loss and locomotor impairment in vivo remains unclear. We evaluated the therapeutic potential of five anti-α-syn sdAbs to clear pathological α-syn in mouse neuronal culture and then demonstrated their in vivo efficacy in a Drosophila model of synucleinopathy. The sdAbs differed in their efficacy to lower levels of phospho-serine 129 α-syn, prevent loss of DA neurons, alleviate mitochondrial dysfunction, improve motor function, and prolong survival in synucleinopathy flies. The most effective sdAb, 2H1, has not been reported before. It binds strongly to the aggregation prone region of α-syn and robustly improves all these disease parameters. Additionally, that sdAb is associated with α-syn in the fly neurons, as shown through proximity dependent turboID biotinylation assays. The sdAb-turboID also biotinylated α-syn-associated proteins involved in synapse/vesicle trafficking pathways, pinpointing the location of their intracellular interaction. Our findings provide an insight into the therapeutic mechanism of action of these sdAbs and strongly support their clinical development.

BACKGROUND AND OBJECTIVES/OBJECTIVE:Degeneration of the central autonomic network with relative sparing of peripheral autonomic neurons underlies neurogenic orthostatic hypotension in patients with multiple system atrophy (MSA). Ampreloxetine, a novel, selective, norepinephrine (NE) reuptake inhibitor, allows once-daily dosing to precisely target residual peripheral autonomic neurons. Based on the hypothesis that patients with MSA would be most responsive and the substantial unmet need for symptomatic therapy in this population, an MSA subgroup analysis was prespecified. METHODS:We conducted a run-in 4-week, parallel-group, randomized controlled trial (SEQUOIA), followed by a pivotal enriched randomized withdrawal (RW) trial with 16-week open-label treatment and 6 weeks of 1:1 RW (REDWOOD). Inclusion criteria for the MSA subgroup included (1) probable or possible MSA, (2) 3-minute orthostatic blood pressure (BP) fall >20/10 mm Hg, and (3) dizziness or lightheadedness score >4 points. Outcome measures included self-reported symptom burden captured on the 10-item OH Questionnaire (OHQ). Differences were analyzed using logistic regression and mixed-model repeated measures analysis. RESULTS:= 0.015). Standing BP remained unchanged from open-label in the ampreloxetine group (systolic: 5.6 ± 4.1; diastolic: 3.7 ± 2.9 [SE] mm Hg) but fell after placebo withdrawal (systolic: -10.0 ± 4.5; diastolic: -6.0 ± 3.1 mm Hg). The catecholamine profile was consistent with NE transporter inhibition. There were no observed increases in supine BP. DISCUSSION/CONCLUSIONS:In a prespecified subgroup analysis of MSA participants in the REDWOOD trial, patients randomized to placebo worsened, whereas those who were randomized to treatment maintained their open-label level of function. TRIAL REGISTRATION INFORMATION/UNASSIGNED:REDWOOD trial, NCT03829657; first submitted to registry January 10, 2019; first participant enrolled February 22, 2019. SEQUOIA trial, NCT03750552; first submitted to registry November 20, 2018; first participant enrolled January 24, 2019. See ClinicalTrials.gov for full-protocol and statistical analysis plan. CLASSIFICATION OF EVIDENCE/METHODS:This study provides Class III evidence that in patients with MSA who had symptomatic benefit on orthostatic hypotension with ampreloxetine, there was no difference in the odds of treatment failures between those maintained on ampreloxetine and those withdrawn to placebo.

BACKGROUND AND OBJECTIVES/OBJECTIVE:Circumferential minimally invasive surgery (cMIS) techniques in adult spinal deformity (ASD) surgery may reduce physiological burden compared with open technique, but their utility in octogenarians has not been previously assessed. METHODS:Operative ASD patients aged 80 years or older with complete baseline (BL) and 2-year postoperative radiographic and health-related quality of life data were assessed and compared by surgical technique: open vs cMIS. Propensity score matching aligned groups by BL Charlson Comorbidity Index (CCI), C7-S1 sagittal vertical axis, pelvic incidence minus lumbar lordosis mismatch, and C7 plumb line. BL and peri/postoperative factors were assessed using analysis of variance and Bonferroni-adjusted analysis of covariance while controlling for BL CCI and posterior fusion length. RESULTS:Thirty-four octogenarian ASD patients met inclusion criteria, of whom 29.4% underwent cMIS and 70.6% underwent open correction. cMIS patients were less likely to require surgical intensive care unit (10% vs 75%, P < .001) and had shorter hospital stays (4.6 vs 10.1 days, P = .013). Open patients reported higher Scoliosis Research Society-22 Appearance and Mental domain scores (both P < .005) and more frequently reached minimal clinically important difference in both domains by 2 years (P = .025, .024). cMIS patients more often required reoperation for radiographic sagittal imbalance by 2 years when controlling for CCI and levels fused (20.0% vs 8.3%, P < .001). No deaths occurred in either group by 2 years. CONCLUSION/CONCLUSIONS:In octogenarians undergoing ASD surgery, cMIS reduced physiological burden but had higher reoperation rates, whereas open surgery showed greater durability.