Faculty Bibliography

Lewy body dementia is a heterogeneous disease that is underdiagnosed and poorly understood. Pathologically, Lewy body dementia is characterised by the accumulation of intraneuronal aggregates of misfolded α-synuclein, known as Lewy bodies and Lewy neurites. The genetic architecture of Lewy body dementia is complex, involving both common genetic variants with small risk effects and rare genetic variants with large effects. Alzheimer's disease pathology frequently coexists with Lewy body pathology and influences the clinical presentation. A deeper understanding of the pathophysiological pathways, including mitochondrial dysfunction, lysosomal dysfunction, and neuroinflammation, can enhance disease modelling, and this knowledge will ultimately facilitate the development of therapeutic interventions. The biological relationships that Lewy body dementia shares with other neurodegenerative and psychiatric disorders might also be crucial for the development of therapeutic strategies.

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.

Human retrotransposon insertions are often associated with diseases. In the case of the neurodegenerative X-Linked Dystonia-Parkinsonism disease, a human-specific SINE-VNTR-Alu subfamily F retrotransposon was inserted in intron 32 of the TAF1 gene. Here, we genomically rewrote a portion of the mouse Taf1 allele with the corresponding 78-kb XDP patient derived TAF1 allele. In mESCs, the presence of the intronic SVAs-rather than the hybrid gene structure-reduces hyTAF1 levels. This leads to transcriptional downregulation of genes with TATA box enriched in their promoters and triggering apoptosis. Chromatin and transcriptome profiling revealed that intronic SVAs are actively transcribed, forming barriers that likely impede transcription elongation. In mice, neuronal lineage TAF1 humanization resulted lethality of male progeny within two months. XDP male mice had severe atrophy centered on the striatum-the same affected brain region in XDP patients. Lastly, CRISPRa-mediated activation of hyTAF1 restored mESC viability, suggesting boosting TAF1 transcription as a therapeutic approach.

Astrocytes, the bushy, star-shaped glial cells of the brain and spinal cord, support the proper development and function of many cells in the central nervous system. In response to disease or injury they transform, adopting varied morphologies, molecular signatures, and functions-this state of transformation is known as reactivity. For over a century, the reactivity of astrocytes has been recognized, but it is the recent surge in technological innovation that has shed light on the diverse nature of this reactivity. It is this developing understanding of the heterogeneity of reactive astrocytes across disease-specific contexts and a spatiotemporal gradient that now excites the astrocyte field. In this review, we discuss the current understanding of reactive astrocyte heterogeneity, highlight the biological implications of this heterogeneity, and propose future approaches to aid in fully understanding the heterogeneity of reactive astrocytes.

Immunotherapies have revolutionized cancer care for many tumor types, but their potential long-term cognitive impacts are incompletely understood. Here, we demonstrated in mouse models that chimeric antigen receptor (CAR) T cell therapy for both central nervous system (CNS) and non-CNS cancers impaired cognitive function and induced a persistent CNS immune response characterized by white matter microglial reactivity, microglial chemokine expression, and elevated cerebrospinal fluid (CSF) cytokines and chemokines. Consequently, oligodendroglial homeostasis and hippocampal neurogenesis were disrupted. Single-nucleus sequencing studies of human frontal lobe from patients with or without previous CAR T cell therapy for brainstem tumors confirmed reactive states of microglia and oligodendrocytes following treatment. In mice, transient microglial depletion or CCR3 chemokine receptor blockade rescued oligodendroglial deficits and cognitive performance in a behavioral test of attention and short-term memory function following CAR T cell therapy. Taken together, these findings illustrate targetable neural-immune mechanisms underlying immunotherapy-related cognitive impairment.

Increasing evidence points to a pivotal role of immune processes in the pathogenesis of Alzheimer disease, which is the most prevalent neurodegenerative and dementia-causing disease of our time. Multiple lines of information provided by experimental, epidemiological, neuropathological and genetic studies suggest a pathological role for innate and adaptive immune activation in this disease. Here, we review the cell types and pathological mechanisms involved in disease development as well as the influence of genetics and lifestyle factors. Given the decade-long preclinical stage of Alzheimer disease, these mechanisms and their interactions are driving forces behind the spread and progression of the disease. The identification of treatment opportunities will require a precise understanding of the cells and mechanisms involved as well as a clear definition of their temporal and topographical nature. We will also discuss new therapeutic strategies for targeting neuroinflammation, which are now entering the clinic and showing promise for patients.

Astrocytes are a highly abundant glial cell type and perform critical homeostatic functions in the central nervous system. Like neurons, astrocytes have many discrete heterogeneous subtypes. The subtype identity and functions are, at least in part, associated with their anatomical location and can be highly restricted to strategically important anatomical domains. Here, we report that astrocytes forming the glia limitans superficialis, the outermost border of the brain and spinal cord, are a highly specialized astrocyte subtype and can be identified by a single marker: myocilin (Myoc). We show that glia limitans superficialis astrocytes cover the entire brain and spinal cord surface, exhibit an atypical morphology, and are evolutionarily conserved from zebrafish, rodents, and non-human primates to humans. Identification of this highly specialized astrocyte subtype will advance our understanding of CNS homeostasis and potentially be targeted for therapeutic intervention to combat peripheral inflammatory effects on the CNS.

Glaucomatous optic neuropathy, or glaucoma, is the world's primary cause of irreversible blindness. Glaucoma is comorbid with other neurodegenerative diseases, but how it might impact the environment of the full central nervous system to increase neurodegenerative vulnerability is unknown. Two neurodegenerative events occur early in the optic nerve, the structural link between the retina and brain: loss of anterograde transport in retinal ganglion cell (RGC) axons and early alterations in astrocyte structure and function. Here, we used whole-mount tissue clearing of full mouse brains to image RGC anterograde transport function and astrocyte responses across retinorecipient regions early in a unilateral microbead occlusion model of glaucoma. Using light sheet imaging, we found that RGC projections terminating specifically in the accessory optic tract are the first to lose transport function. Although degeneration was induced in one retina, astrocytes in both brain hemispheres responded to transport loss in a retinotopic pattern that mirrored the degenerating RGCs. A subpopulation of these astrocytes in contact with large descending blood vessels were immunopositive for LCN2, a marker associated with astrocyte reactivity. Together, these data suggest that even early stages of unilateral glaucoma have broad impacts on the health of astrocytes across both hemispheres of the brain, implying a glial mechanism behind neurodegenerative comorbidity in glaucoma.

The relative ease of generation and proliferation of omics datasets has moved considerably faster than the effective dissemination of these data to the scientific community. Despite advancements in making raw data publicly available, many researchers struggle with data analysis and integration. We propose sharing analyzed data through user-friendly platforms to enhance accessibility. Here, we present a free, online tool, for sharing basic omics data in a searchable and user-friendly format. Importantly, it requires no coding or prior computational knowledge to build-only a data spreadsheet. Overall, this tool facilitates the exploration of transcriptomic, proteomic, and metabolomics data, which is crucial for understanding glial diversity and function. This initiative underscores the importance of accessible molecular data in advancing neuroscience research.