Faculty Bibliography

Formaldehyde, a reactive aldehyde widely present in the environment and associated with occupational exposure, has been linked to cognitive impairment and Alzheimer's disease (AD) in multiple epidemiological and animal studies. However, its contribution to AD-like pathology in human neural models remains poorly understood. We utilized a 3D culture system of human neural progenitor cells (ReNcell VM) differentiated into neurons and glial cells to model chronic formaldehyde exposure. Additionally, we established a 3D human AD model by transducing ReN cells with APP and PSEN1 mutations to assess the effects of formaldehyde in an AD genetic background. Long-term formaldehyde exposure (up to 12 weeks) induced a dose-dependent increase in Aβ40, Aβ42, APP, and phosphorylated tau levels in both wild-type and AD-mutant 3D cultures. These changes mimic hallmark features of AD neuropathology, suggesting that formaldehyde acts as a pathological driver in both sporadic and familial contexts. Our study provides direct evidence that chronic formaldehyde exposure may initiate and accelerate amyloid and tau pathologies in 3D human neural cell models. These findings support growing concerns about formaldehyde as a modifiable risk factor in neurodegeneration.

BACKGROUND:Primary hyperoxaluria (PH) is a family of three rare, autosomal recessive genetic disorders that can result in recurrent kidney stones, progressive chronic kidney disease (CKD), and kidney failure. PH prevalence is underestimated due to its varying presentation and lack of awareness; delays in diagnosis can lead to substantial burdens on the healthcare system. METHODS:This retrospective, observational claims analysis evaluated disease burden and cost of care in patients who had PH, PH with CKD, or CKD alone. Data from the Merative MarketScan Commercial Claims and Encounters databases and the Centers for Medicare and Medicaid Services Medicare Fee-for-Service Limited Data Set were assessed during the study period of January 1, 2017, to December 31, 2021. PH prevalence was calculated based on the sample population within each data source. RESULTS:The study sample included 326 patients who had PH; applying projection factors to the US population, an estimated 4500 patients had a diagnosis of PH in 2021. Among these patients, 37% were estimated to have PH with CKD (65% of whom had early CKD, 33% had advanced CKD, and 2% had stage reported as unknown). Patients who had CKD alone (n = 845) were matched with patients who had PH with CKD (n = 169). Patients who had PH with CKD were significantly more burdened with kidney stones (p < 0.01) than patients who had CKD alone. Higher rates of pharmacotherapy and medical treatments were observed in patients who had PH with CKD versus patients who had CKD alone. Median semi-annual total all-cause healthcare costs were greater in patients who had PH with CKD than in patients with CKD alone, regardless of CKD stage ($54,154 in patients who had PH with advanced CKD vs. $35,016 in patients with advanced CKD alone; $9,784 in patients who had PH with early CKD vs. $5,572 in patients with early CKD alone). CONCLUSIONS:CKD stage progression among patients who had PH is associated with increasing all-cause costs, suggesting that early diagnosis and treatment of PH to limit the progression to advanced CKD could represent an opportunity to alleviate not only PH symptoms, but also the healthcare cost burden.

Inflammation drives various diseases, including cardiovascular, neurodegenerative, and oncological disorders, by altering immune cell dynamics in hematopoietic niches. The bone marrow is the primary site for hematopoietic stem and progenitor cell activity. Here, we present a novel, noninvasive approach using multispectral optoacoustic tomography (MSOT) to track oxygenation dynamics in the murine calvarial bone marrow during acute systemic inflammation induced by lipopolysaccharide (LPS). Our MSOT system provided real-time, label-free imaging of hemoglobin oxygen saturation (sO₂), revealing significant reductions in sO₂ levels in lipopolysaccharide-treated mice, indicative of increased oxygen consumption. Co-registration with microCT enabled precise vascular mapping. Hypoxia was confirmed by ex vivo Pimonidazole staining and optical imaging and was associated with elevated neutrophil counts and enhanced hematopoietic activation. These findings demonstrate MSOT's potential for noninvasive imaging of marrow oxygenation, offering insights into inflammation-driven hematopoietic activation and supporting the development of therapies targeting oxygen-sensitive pathways.

BACKGROUND:Glaucoma Research Foundation's third Catalyst for a Cure team (CFC3) was established in 2019 to uncover new therapies for glaucoma, a leading cause of blindness. In the 2021 meeting "Solving Neurodegeneration," (detailed in Mol Neurodegeneration 17(1), 2022) the team examined the failures of investigational monotherapies, issues with translatability, and other significant challenges faced when working with neurodegenerative disease models. They emphasized the need for novel, humanized models and proposed identifying commonalities across neurodegenerative diseases to support the creation of pan-neurodegenerative disease therapies. Since then, the fourth Catalyst for a Cure team (CFC4) was formed to explore commonalities between glaucoma and other neurodegenerative diseases. This review summarizes outcomes from the 2023 "Solving Neurodegeneration 2" meeting, a forum for CFC3 and CFC4 to share updates, problem solve, plan future research collaborations, and identify areas of unmet need or opportunity in glaucoma and the broader field of neurodegenerative disease research. MAIN BODY/METHODS:We summarize the recent progress in the field of neurodegenerative disease research and present the newest challenges and opportunities moving forward. While translatability and disease complexity continue to pose major challenges, important progress has been made in identifying neuroprotective targets and understanding neuron-glia-vascular cell interactions. New challenges involve improving our understanding of the disease microenvironment and timeline, identifying the optimal approach(es) to neuronal replacement, and finding the best drug combinations and synergies for neuroprotection. We propose solutions to common research questions, provide prescriptive recommendations for future studies, and detail methodologies, strategies, and approaches for addressing major challenges at the forefront of neurodegenerative disease research. CONCLUSIONS:This review is intended to serve as a research framework, offering recommendations and approaches to validating neuroprotective targets, investigating rare cell types, performing cell-specific functional characterizations, leveraging novel adaptations of scRNAseq, and performing single-cell sorting and sequencing across neurodegenerative diseases and disease models. We focus on modeling neurodegeneration using glaucoma and other neurodegenerative pathologies to investigate the temporal and spatial dynamics of neurodegenerative disease pathogenesis, suggesting researchers aim to identify pan-neurodegenerative drug targets and drug combinations leverageable across neurodegenerative diseases.

Although many internalized G protein-coupled receptors (GPCRs) continue to signal, the mechanisms and outcomes of intracellular GPCR signaling are uncertain due to the challenges of measuring organelle-specific signals and of selectively antagonizing receptors in intracellular compartments. Herein, genetically encoded biosensors targeted to the plasma membrane and early endosomes were used to analyze compartmentalized signaling of protease-activated receptor 2 (PAR₂); the propensity of nanoparticles (NPs) to accumulate in endosomes was leveraged to preferentially antagonize intracellular PAR₂ signaling of pain. PAR₂ agonists evoked sustained activation of PAR₂, Gαq, and β-arrestin-1 in early endosomes and activated extracellular signal regulated kinase (ERK) in the cytosol and nucleus, measured with targeted biosensors. Fluorescent dendrimer and core-shell polymeric NPs accumulated in endosomes of HEK293T cells, colonic epithelial cells, and nociceptors, detected by confocal microscopy. NPs efficiently encapsulated and slowly released AZ3451, a negative allosteric PAR₂ modulator. NP-encapsulated AZ3451, but not unencapsulated AZ3451, rapidly and completely reversed PAR₂, Gαq, and β-arrestin-1 activation in early endosomes and ERK activation in the cytosol and nucleus. When administered into the mouse colon lumen, fluorescent dendrimer NPs accumulated in endosomes of colonocytes and polymeric NPs accumulated in neurons, sites of PAR₂ expression. Both NP formulations of AZ3451, but not unencapsulated AZ3451, caused long-lasting analgesia and normalized aberrant behavior in preclinical models of inflammatory bowel disease. These results provide evidence that PAR₂ endosomal signaling mediates pain and that nanomedicines that antagonize PAR₂ in endosomes effectively relieve pain. NP-mediated delivery may improve the efficacy of other GPCR antagonists for treatment of diverse diseases.

Astrocytic Ca²⁺ activity regulates activity-dependent synaptic plasticity, but its role in learning-related synaptic changes in the living brain remains unclear. We found that motor training induced synaptic potentiation on apical dendrites of layer 5 pyramidal neurons, as well as astrocytic Ca²⁺ rises in the mouse motor cortex. Reducing astrocytic Ca²⁺ led to synaptic depotentiation during motor training and subsequent impairment in performance improvement. Notably, synaptic depotentiation occurred on a fraction of dendrites with repetitive dendritic Ca²⁺ activity. On those dendrites, dendritic spines that were active before dendritic Ca²⁺ activity underwent CaMKII-dependent size reduction. In addition, the activation of adenosine receptors prevented repetitive dendritic Ca²⁺ activity and synaptic depotentiation caused by the reduction of astrocytic Ca²⁺, suggesting the involvement of ATP released from astrocytes and adenosine signaling in the processes. Together, these findings reveal the function of astrocytic Ca²⁺ in preventing synaptic depotentiation by limiting repetitive dendritic activity during learning.

Theories propose that speech production can be approximated as a temporal reversal of speech perception. For example, phonological code is assumed to precede phonetic encoding in the motor system during speech production. However, empirical neural evidence directly testing the temporal order hypothesis remains scarce, mostly because of motor artifacts in non-invasive electrophysiology recordings and the requirements of both temporal and spatial precision. In this study, we investigated the neural dynamics of speech production using stereotactic electroencephalography (sEEG). In both onset latency analysis and representational similarity analysis (RSA), activation in the auditory region of the posterior superior temporal gyrus (pSTG) was observed before articulation, suggesting the availability of auditory phonological code before production. Surprisingly, the activation in the motor region of the inferior frontal gyrus (IFG) preceded that of pSTG, suggesting that the phonological code in the auditory domain may not necessarily be activated before the encoding in the motor domain during speech production.

Mothers exhibit an increased appetite to cope with the energetic demands of lactation. A new study has identified a neural circuit that interfaces between food seeking and pup caring.

By improving the delivery and tumor retention of chemotherapeutics, nanomedicines hold potential for cancer treatment. The usefulness of nanoparticle (NP)-encapsulated analgesics for the cancer pain treatment is comparatively unexplored. We investigated whether NPs encapsulating olcegepant (OCP), an antagonist of the calcitonin receptor-like receptor (CLR) for the calcitonin gene-related peptide (CGRP), effectively relieved oral cancer pain in mice. Because persistent endosomal CLR signaling in Schwann cells mediates craniofacial pain, we reasoned that the predisposition of NPs to accumulate in endosomes could be leveraged to effectively relieve oral cancer pain. By expressing biosensors for activated CLR, Gα proteins and β-arrestins in HEK293T and Schwann cells, we found that CGRP activates CLR signaling first at the plasma membrane and then in early, late and recycling endosomes and the cis- and trans-Golgi apparatus. We synthesized biocompatible NPs encapsulating OCP and fluorophores by integrating hydrophobic ion pairing nanoformulation with Flash NanoPrecipitation. NPs slowly released OCP and accumulated in early endosomes, leading to sustained inhibition of endosomal CLR signaling in HEK293T and Schwann cells. Oral cancers were established in mice, which led to heightened pain-like responses. After intra-tumoral injection, NPs were retained in tumors for at least one week. OCP-loaded NPs almost completely reversed allodynia and hyperalgesia for a prolonged period, whereas unencapsulated OCP had small and transient effects. The NP accumulation in endosomal sites of pain signaling, the sustained release of antagonist, and the retention of NPs in tumors explain their beneficial actions. Thus, NP-encapsulation holds promise for the relief of painful cancers that are inadequately treated by opioids.

INTRODUCTION/BACKGROUND:The New York University Caregiver Intervention plus Enhanced Support Project is a randomized controlled trial of a family-based psychosocial intervention to enhance social support and reduce cardiometabolic risk for Chinese and Korean American dementia caregivers, using culturally tailored recruitment strategies. METHODS:We reviewed reflections from research staff, weekly meeting minutes, debriefing sessions, and progress reports, to identify key challenges and approaches to engaging participants. RESULTS:Key challenges included reluctance to involve family members, dementia stigma, and resistance to involving family. In response, we engaged online communities, partnered with local organizations, participated in events, and adapted recruitment messages to cultural norms. For the Chinese community, we focused on practical skills while for the Korean community, we emphasized caregiving strategies and the personal/social benefits of participation, reducing rejection rates. DISCUSSION/CONCLUSIONS:Our findings underscore the importance of culturally tailored recruitment strategies in dementia research. Respectful, sensitive, and culturally informed approaches can significantly enhance engagement and participation. HIGHLIGHTS/CONCLUSIONS:Culturally adapted recruitment strategies improve study engagement with Chinese and Korean American dementia caregivers. Community partnerships with local social services agencies are essential for recruitment success. Culturally relevant social media applications were integrated to increase accessibility for study participants. This study uniquely targets and recruits Chinese and Korean American dementia caregivers with metabolic syndrome-related symptoms, incorporating a psychological intervention alongside biomarker data collection. The iterative adaptation of recruitment methods and tailored messaging to specific ethnic groups ensure the intervention is culturally aligned, enhancing both participation and relevance to the caregivers' unique health and caregiving contexts.