Alzheimer's Disease (AD) and AD-Related Dementias (ADRDs) represent a growing public health challenge, underscoring the urgent need for accessible and reliable biomarkers for early diagnosis, progression monitoring, and therapeutic response assessment. The search for reliable and accessible biomarkers remains a critical challenge in advancing early diagnosis and precision medicine. Vitreous humor (VH), a transparent ocular fluid in close anatomical and physiological connection with the central nervous system (CNS), represents a promising yet underutilized biofluid for biomarker discovery. Recent studies suggest that VH has potential as a proxy for brain neuropathology. We hypothesize that VH may also provide useful biomarker potential for other neurodegenerative diseases. We analyzed postmortem paired biosamples from VH, cerebral spinal fluid (CSF) and blood plasma from individuals with AD and other ADRDs to test this hypothesis. Postmortem blood plasma, CSF, and VH samples ( n  = 133) were obtained from the Carroll A. Campbell, Jr. Neuropathology Laboratory at the Medical University of South Carolina. Samples were tested for Aβ40, Aβ42, GFAP, and NfL. Relative concentrations were measured using the Simoa Neurology 4-Plex E (N4PE+) Advantage PLUS assay with a 4- fold dilution for blood plasma, 25-fold dilution for VH and 400-fold dilution for CSF on HD-X analyzer (Quanterix, MA). All samples were processed per manufacturer's instructions in the immunoassay kits; we are currently analyzing the same samples for p -Tau217. Artificial intelligence (AI) predictive modeling (including neural networks) using retrospective and prospective cohorts is being used to ensure accuracy and reliability. Our findings reveal biomarker signatures (Aβ40, Aβ42, GFAP, and NfL) in the VH of AD and ADRDs. Moreover, we highlight the potential of these biomarkers for early disease detection and differentiation of AD from ADRD subtypes. We analyzed the relationship between VH biomarkers, blood plasma, CSF, clinical, and neuropathological measures. VH may be a valuable source for biomarker discovery in neurodegenerative disease such as AD, diffuse Lewy body disease and frontotemporal dementia (FTD). We anticipate that integration of VH and other biomarkers with AI-driven data analysis will enhance diagnostic capabilities, ultimately supporting neurology and memory care clinicians in the future.

Alzheimer's disease (AD) in the United States is predicted to double by 2060 from 6.9 to13.8 million cases. AD is characterized by the abnormal buildup of beta-amyloid plaques and irregular protein tau structures in various regions of the brain. This accumulation of protein impairs memory and cognitive function that disrupts the daily life of those afflicted with the disease. Factors for developing AD are age, genetics, health conditions and lifestyle choice, such as Alcohol Use Disorder. Alcohol Use Disorder can independently promote damage, accumulation of plaques, vascular injury and neuroinflammation to the areas of the brain. Early diagnosis of these changes is paramount to detection of AD and associated diseases, this has been shown to be possible by assessing the eye. We hypothesize that morphological changes associated with AD and other neurodegenerative markers (established and novel) in the ocular tissue of our rat model that will help to clarify the relationship between alcohol consumption and AD development. Our collaborators exposed wild type and TgF344-AD rats, an AD model heterozygous for human mutant APPswe/PS1dE9, ages 4-7 months to 200 proof alcohol in vaporization chambers. Treatment was administered intermittently, acutely or chronically, during adolescence (≈ p28-p56) and/or adulthood (≈ p70-p98). Experimental groups included rats that 1) did not receive alcohol at all or received alcohol 2) in adolescence only, 3) in adulthood only, or 4) in both adolescence and adulthood. Rats also received air only as a control treatment. We obtained eyes from these rats and subjected them to histological processing and staining with hematoxylin and eosin (H&E) and several known and novel markers of neurodegeneration. Our board-certified neuropathologist reviewed reported on each stain. A total of 180 eyes were harvested from our experimental rat groups. Extensive β-amyloid staining has been performed in brains harvested from these animals’ following treatment. Additionally, pTau staining with CP13 is currently being executed. We plan to correlate staining from brain tissue with ocular tissue. Identifying novel biomarkers associated with alcohol consumption can provide novel insights into how lifestyle choices contribute to AD development.

Deep learning-based brain age models quantify regional deviations from normative aging and may capture structural changes relevant to dementia risk. Plasma phosphorylated tau-217 (p-tau217) is a scalable Alzheimer's disease biomarker, but its relationship to brain aging and cognition in cognitively unimpaired adults is unclear. In this cross-sectional study, we tested whether brain age patterns serve as indirect pathways linking plasma p-tau217 to cognition in the Aging Brain Cohort (ABC). Neuroimaging data from 518 adults (mean age = 43.7 years, 70.8% female) were analyzed using a validated deep learning brain age model, and decomposed via exploratory factor analysis into six gradients: frontal, dorsal, ventral, left frontotemporal, right frontotemporoparietal, and bilateral parietal. In a parallel mediation model including all six gradients as simultaneous mediators in adults aged ≥60 years (N = 71), a significant specific indirect effect of plasma p-tau217 on Montreal Cognitive Assessment (MoCA) scores was observed through accelerated right frontotemporoparietal aging (β = -0.111, 95% CI [-0.313, -0.010], p = 0.031). No other indirect pathways were significant, and neither the total nor direct effect was significant. These findings suggest a specific brain aging phenotype as a potential intermediate pathway linking tau-related pathology to cognition prior to clinical impairment.

More than 6 million Americans were living with Alzheimer's Disease (AD) in 2024, and that number is expected to triple over the next 40years. Although effective treatments for AD are becoming available, these are likely to be most effective when given early in the course of the disease. Unfortunately, biomarkers that effectively identify the early stages of AD are not yet available. However, there is growing interest in whether eye pathology can be used for this purpose. We have therefore performed mass spectrometry on 123 vitreous humor (VH) samples from autopsied patients with AD or AD-related dementias (ADRDs) to identify potential biomarkers. Following preparation with EasyPep 96 well plate kits, protein was reduced, alkylated, and digested with trypsin and Lys-C. Resulting peptides were analyzed by LC-MS/MS on an Orbitrap Exploris 480 MS in DIA mode. Pooled samples were analyzed in DDA mode to supplement database searching using Spectronaut 19.6 Direct-DIA+. For protein identification, an FDR<0.01 and a minimum of 2 unique proteotypic peptides were required. Quantification was based on peak areas of 3-6 MS2 fragment ions per peptide. Data were statistically evaluated using Perseus v1.6.15. Because of contamination with blood proteins, albumin and other blood proteins were removed. Median normalized, log2 transformed protein intensities were filtered to retain proteins quantified in 70% of the samples in one group and missing values were imputed from a down shifted normal distribution. Protein intensities were compared among groups using Student's t-test. Log2 fold changes between groups, p -values, and q -values were reported. Proteins identified through this approach have been implicated in neuronal development, neuroprotective functions, and neurodegenerative disorders. Proteins upregulated in early-onset AD patients were found to be calcium modulators. Many proteins upregulated in late-onset patients performed roles in neuroinflammation. Interestingly, a comparison of proteins between early and late onset AD revealed an increase in proteins involved in energy metabolism, splicing and ribosome assembly, and vesicular trafficking in early onset AD. The identification of novel AD biomarkers in the vitreous humor suggests that these proteomic analyses are identifying differences in the pathogenic mechanisms of early and late-onset AD.

Introduction:Post-traumatic stress disorder (PTSD) is increasingly recognized as a neuroimmune disorder in which disrupted neuron-glia interactions contribute to long-term cognitive and emotional dysfunction. However, the cellular and molecular basis of immune imbalance in the human hippocampus remains unclear. Methods:We performed single-nucleus RNA sequencing on postmortem hippocampal tissues from donors with PTSD and matched controls, identifying 10 major cell types, with particular emphasis on neurovascular and glial populations. Differential expression, pathway enrichment, pseudotime trajectory, and cell-cell communication analyses were applied to characterize cellular and molecular alterations. Results:PTSD samples showed prominent activation of stress-response and inflammatory signaling across astrocytes, microglia, endothelial cells, and mural cells. Microglia and astrocytes underwent robust transcriptional reprogramming with enrichment of immune-related pathways, while endothelial and mural cells exhibited inflammation and impaired blood-brain barrier homeostasis. Trajectory analyses revealed altered state transitions in astrocytes and microglia, indicating dysregulated responses to stress. Furthermore, cell-cell communication analysis uncovered markedly reduced interactions between astrocytes or microglia with excitatory neurons and oligodendrocyte lineage cells, particularly involving stress- and inflammation-related ligand-receptor pairs. Discussion:These findings demonstrate that PTSD is characterized by immune imbalance at both cellular and intercellular levels, driven by maladaptive glial activation and disrupted neuron-glia communication. Our study provides a comprehensive single-cell atlas of the hippocampal neuroimmune landscape in PTSD and highlights dysfunctional glial-neuronal interactions as a central mechanism underlying disease pathogenesis.

Non-specific Alzheimer's Disease (AD) biomarkers like glial fibrillary acidic protein (GFAP) and neurofilament light chain (Nfl) are now included in the diagnosis and staging of AD, but more work is needed to fully understand their utility in early detection of AD. The present study examined plasma GFAP, Nfl, amyloid beta (Aβ) 40, and Aβ42 in individuals with AD, mild cognitive impairment (MCI) and subjective cognitive decline (SCD) who were either amyloid positive (A+) or negative (A-) according to florbetapir positron emission tomography scan neuroradiological read. The goal was to determine whether individuals with preclinical AD (SCD/A+) show biomarker profiles similar to those expected in AD and MCI (i.e., higher GFAP and Nfl and lower Aβ40 and Aβ42) compared to SCD individuals at lower risk (SCD/A-). Individuals with AD (24 A+, 5 A-), MCI (21 A+, 17 A-) and SCD (5 A+, 11 A-), as determined by clinician referral, completed a blood draw and neuropsychological testing. Blood samples were collected, processed, and stored per previously published guidelines. Plasma samples were assayed using the Neurology 4-Plex E+ assay on the HD-X analyzer (Quanterix, MA). Coefficients of variation for all assays were ≤5%. Generalized linear models (GLMs) with false discovery rate correction examined the effects of diagnosis severity (AD, MCI, SCD) and amyloid status (A+, A-) on plasma levels for each biomarker and the Aβ42/Aβ40 ratio, with covariates of age and sex. Associations between biomarkers and global cognitive functioning, as measured by the Montreal Cognitive Assessment (MoCA), were also examined. The Severity x Amyloid status interaction indicated that GFAP was higher (χ 2 (2)=6.9, p  = .032) and Aβ42/Aβ40 was lower (χ 2 (2)=13.1, p  = .001) in AD/A+ versus AD/A- and in SCD/A+ versus SCD/A-, but amyloid status did not moderate GFAP or Aβ42/Aβ40 in MCI. GLMs for Nfl, Aβ 40, and Aβ 42 did not yield significant effects. GFAP was negatively correlated with MoCA for MCI (ρ=-.61, p  <.001) and SCD (rρ=-.59, p  = .016) groups but not for AD (ρ =-.15, p  = .45). Individuals with preclinical AD (SCD/A+) showed biomarker profiles consistent with AD (higher GFAP; lower Aβ42/Aβ40) and GFAP was associated with poorer global cognition in MCI and SCD.

Neurodegenerative biomarkers, including Amyloid-β40, 42, Neurofilament light chain (NfL), Glial fibrillary acidic protein (GFAP), and p -Tau 217, are considered promising hallmarks of Alzheimer's Disease and Related Dementias (AD/ADRD). These biomarkers can be collected antemortem or postmortem, with each providing distinct insights into the role of neurodegenerative biomarkers in AD/ADRD. Biomarkers collected from living individuals provide an understanding of treatment effects and biological responses, while postmortem data offers an understanding of the disease's end-stage manifestation. Integrating these different sources of data is crucial in enhancing a comprehensive knowledge regarding the biological mechanisms of cognitive decline and AD/ADRD. Therefore, the aims of this study are to introduce a case of collaboration between two institutions with access to two distinct datasets and present integrative results from the findings of each dataset. Antemortem data comes from the Elucidating the Necessary Active Components of Training (ENACT) data, a randomized controlled trial designed to test the transfer effects of cognitive training. ENACT has collected blood samples from a subsample of its participants ( n  = 60) during baseline and posttest. The samples are currently stored at Clemson University and will be shipped to the Medical University of South Carolina (MUSC) for the analyses of the neurodegenerative biomarkers on MUSC's Quanterix HD-X system. Aβ40, 42, NfL and GFAP will be analyzed using the NEUROLOGY 4-PLEX assay and p -Tau 217 will be analyzed using ALZpath p -Tau 217. For the postmortem data from a different source, MUSC has completed HD-X analysis on postmortem blood and cerebrospinal fluid (CSF) specimen for Amyloid-β 40,42, GFAP, and NfL. From ENACT and postmortem datasets, we hypothesize that lower peripheral levels of Amyloid-β1-42, higher Amyloid-β1-40, lower amyloid-β 42/40 ratio, higher NfL, and higher p -Tau 217 will each relate to poorer cognition or greater progression of neurodegenerative diseases. From ENACT data specifically, we also expect to identify the mechanistic role of neurodegenerative biomarkers in cognitive training transfer effects. Findings from this study will provide an example of how collaborations between two institutions with distinct datasets can foster a comprehensive understanding of neurodegenerative biomarkers as they relate to cognitive decline and AD/ADRD pathology.

As oncogenic pathways are highly conserved in vertebrates, genetically engineered mouse models can potentially be used to identify therapeutic targets relevant to rare human cancers such as malignant peripheral nerve sheath tumors (MPNSTs). To test this, genome-scale shRNA screens designed to identify genes driving proliferation and survival were performed in five MPNST cultures derived from myelin protein zero-glial growth factor beta 3 (P0-GGFβ3) mice and three human MPNST cell lines. Several hundred gene hits mediating proliferation and survival were identified in human and mouse MPNST cells, many of which have been implicated in proliferation and survival in other cancers and/or mediate the pathogenesis of other cancer types. These hits and their associated signaling pathways extensively overlapped in human and mouse MPNST cells. A drug discovery pathway based on the Drug-Gene Interaction Database was developed to identify hits encoding druggable targets. Five druggable targets were selected for validation, with four of the five agents tested (the DNA polymerase α1 inhibitor clofarabine, the DNA nucleotidylexotransferase inhibitor cordycepin, the BCL6 inhibitor 79-6, and the lysophosphatidic acid receptor 1/3 inhibitor Ki16425) proving effective against human MPNST cells. Clofarabine was especially effective, potently reducing cell numbers at low nanomolar concentrations and inducing a senescent phenotype, possibly via the p53/p21 pathway. These results demonstrate the utility of cross-species functional oncogenomics for the discovery of novel therapeutic targets relevant to human MPNSTs and suggest that clofarabine warrants further evaluation for its therapeutic potential.

Introduction:Sepsis is increasingly recognized as a major precipitant of long-term cognitive impairment, yet the cellular mechanisms underlying hippocampal vulnerability remain elusive. Methods:We performed single-nucleus RNA sequencing of human hippocampal tissues from sepsis and control patients to profile neurovascular cell populations and their transcriptional changes. Results:We identified profound neurovascular alterations involving 21 distinct cell populations. Astrocytes and microglia exhibited marked polarization: Astrocyte 2 showed simultaneous upregulation of neurotoxic A1 and neuroprotective A2 gene signatures in sepsis, whereas Astrocyte 1 displayed reduced A1 activity and a relatively quiescent profile. Microglia 2 demonstrated a prominent M1-like inflammatory signature, including elevated HLA-DRA, IL1B, and TNF, while Microglia 1 downregulated both M1 and M2 markers, suggesting a hypo-responsive state. Intercellular communication analysis revealed intensified astrocyte-microglia interactions in the septic hippocampus. Endothelial and mural cells exhibited transcriptional signatures of blood-brain barrier disruption, oxidative stress, and compromised vascular homeostasis. Key molecular pathways associated with antigen presentation, cytokine signaling, and vascular permeability were selectively activated across neurovascular compartments. Discussion:These findings uncover a coordinated glial and vascular response to systemic inflammation, driven in part by dysfunctional astrocyte-microglia crosstalk and pro-inflammatory polarization. Such changes may underlie blood-brain barrier breakdown and contribute to sustained neuroinflammation and cognitive decline in sepsis survivors. Targeting glial-vascular signaling axes and modulating astrocyte or microglial polarization states may offer promising avenues for therapeutic intervention in post-sepsis neurological sequelae.

The role that neurotrophins, such as nerve growth factor, play in the pathogenesis of neurodegenerative diseases has long been appreciated. However, the neuregulin (NRG) family of growth factors and/or their v-erb-B2 avian erythroblastic leukemia viral oncogene homolog (ERBB) receptors have also been implicated in the pathogenesis of conditions, such as Alzheimer disease (AD), frontotemporal lobar degeneration (FTLD), and amyotrophic lateral sclerosis (ALS). In this review, we consider the structural variability of NRG isoforms generated by alternative RNA splicing, the use of multiple promoters and proteolysis, and the impact of this structural variability on neuronal and glial physiology during development and adulthood. We discuss the NRG receptors ERBB2, ERBB3, and ERBB4, how activation of each of these receptors further diversifies NRG actions in the central nervous system, and how dementia-related proteins, such as γ-secretase modulate the action of NRGs and their ERBB receptors. We then turn to the abnormalities in NRG and ERBB expression and function evident in human AD and mouse AD models, how these abnormalities affect brain function, and attempts to use NRGs to treat AD. Finally, we discuss the effects of NRG on the survival and function of neurons relevant to FTLD and ALS, alterations in NRG/ERBB signaling identified in these conditions, and the recent discovery of multiple human pedigrees in which autosomal dominant FTLD/ALS potentially results from point mutations in ERBB4.

Epidemiological studies have identified an association between the exposure to neurotoxic heavy metals such as cadmium (Cd) and an increased risk for Alzheimer's disease (AD). However, the cellular and molecular mechanisms by which Cd or lead (Pb) exposure affects AD pathogenesis and progression are largely unknown. The goal of this study was to determine how Cd and Pb exposure impact cognitive function and AD progression using the 5xFAD transgenic mouse model of AD. Juvenile (5-weeks old) 5xFAD mice were challenged with 0.2% Pb or 0.002% Cd in drinking water for 6 weeks to model chronic environmental exposures. Y-maze tests were performed to assess spatial memory and learning ability. The Open Field Maze test was employed to examine anxiety-like behaviors. Senescent cells were determined using senescence-associated β-galactosidase staining. Quantitative RT-PCR assays were performed to measure expression levels of senescence markers and senescence-associated secretory phenotype (SASP) related cytokines. Immunofluorescence and confocal microscopy were used to analyze senescent cells and neuroinflammation markers in brain tissues. Cd and Pb both can accelerate the pace of amyloid beta (Aβ) plaque formation and the decline of cognitive functions in 5xFAD mice. Even at a 100-fold lower dose, chronic Cd exposure causes a greater level of Aβ deposition and cognitive deficits than Pb does, indicating that Cd is more potent than Pb in exacerbating AD progression. Mechanistically, we found that the increased expression of the p16 Ink4a senescence marker was more pronounced in the hippocampus of Cd-exposed mice compared to those treated with Pb. Notably, Cd upregulates the expression of the SASP marker IL-6 preferentially in the hippocampus over the cortex, suggesting a spatial difference in Cd-induced increase in neuroinflammation. Furthermore, in vitro mechanistic studies reveal that Cd exposure induces premature senescence in human microglial cells, and senescent microglia release high levels of IL-6, a major modulator of neuroinflammation. Our studies demonstrate that chronic exposure to Cd or Pb can exacerbate cognitive deficits and AD progression in 5xFAD mice. Mechanistically, we discovered that Cd exposure-induced acceleration of AD progression was associated with increased levels of senescent cell burden and neuroinflammation in the hippocampus.

Frontotemporal dementia (FTD) involves progressive deterioration of behavior, executive function, personality/traits and is evident structurally as frontotemporal lobar degeneration (FTLD). FTLD with pathological TDP43 neural/glial inclusions (FTLD-TDP), often coexists with TDP43-positive amyotrophic lateral sclerosis (ALS). Several families have been identified that inherit autosomal dominant FTLD/ALS or ALS alone and mutations in the gene encoding the ERBB4 receptor tyrosine kinase (RTK). Although the neuropathology associated with ERBB4 mutations remains obscure, ERBB4 with p.R927Q or p.I712M mutations show reduced phosphorylation when stimulated with the ERBB4 ligand neuregulin-1β, suggesting that reduced ERBB4 activity causes FTLD/ALS or ALS. We generated mice carrying p.I712M (familial FTLD/ALS) or p.R927Q (familial ALS only) Erbb4 mutations. We performed initial studies of behavior (Barnes Maze), gait-mobility (Catwalk-XT) and body composition (DXA scans) on Erbb4 heterozygous and homozygous mutants and wild-type littermates. Barnes Maze Acquisition was performed on males ( N  = 4-5/genotype) after habituation and several days training. Heatmaps of grouped averages for acquisition day 5 show that ErbB4-R927Q mutants (homozygotes > heterozygotes) take longer finding the goal box, suggesting a gene dosage-dependent defect in spatial learning. CatWalk-XT was performed on Erbb4-R927Q mutant females ( N  = 4-6/genotype), with six complaint post-training walks/animal. Significantly lower mean intensities of the most intense paw prints occurred in the hindlimbs of mutants (Tukey's 2-way ANOVA). Multiple gene-dosage-dependent trends in altered gait metrics occurred, including footfall patterns, 2D/3D mean/max intensities, footfall sequence, print positions, standing and diagonal mean phase dispersions. DXA scans on Erbb4-R927Q mutant and wild-type males ( N  = 5-9 per genotype) showed decreased body weights and fat percentages in homozygotes. Whole body and limb regions of interest showed decreases in bone mineral density and content that was greater in homozygotes than in heterozygotes. Initial findings suggest gene dosage-dependent abnormalities in Erbb4-R927Q mutants that have features of FTLD and ALS. A wider battery of tests on more animals, at different ages and including the Erbb4-I712M mutants are underway. Neuropathology is being assessed following consensus recommendations for FTLD and ALS. Stereology/morphometry and other methods will assess loss of ErbB4 -expressing inhibitory interneurons and synaptic loss and how this evolves temporally.

South Carolina has an extraordinarily high prevalence of Alzheimer's disease (AD) and AD-related dementias (ADRDs), with approximately 122,699 individuals living with dementia. Mapping of ICD-10 codes shows that these diseases are non-uniformly distributed, with multiple “hot spots” in the state. Due to the complexity of these diseases, a post-mortem examination of the brain is required for an accurate diagnosis. The Carroll A. Campbell, Jr. Neuropathology Laboratory (CCNL) at the Medical University of South Carolina (MUSC) has thus performed detailed histologic examination of 343 cases to define the causes of dementia in South Carolina, determine the prevailing ADRD type across SC and whether these deviated from national averages and establish whether specific kinds of neurodegenerative diseases were concentrated in the “hot spots”. Donors were recruited via physicians, community outreach, and our website. Gross and microscopic examination of the brain was performed following consensus recommendations and using a panel of stains including hematoxylin and eosin (H&E), modified Bielschowsky stains, and immunostains for Abeta, hyperphosphorylated tau, alpha-synuclein, p62, p -TDP43, 3-repeat and 4-repeat tau. All cases were reviewed by a board-certified neuropathologist. Diagnoses were mapped at a zip-code level. The 343 cases included 195 male and 148 female donors, with the average age of donors being 73.8 years. 148 cases (43.1%) had an AD diagnosis alone or in combination with another disease. 20.3% of the AD cases were early onset AD, as opposed to the usual 5-10%. Frontotemporal lobar degeneration (FTLD)-tau represented 63.6% of the FTLD cases (normally 45%) of cases, with FTLD-TDP representing 26.4% of cases (normally 45%). Multiple system atrophy also occurred at a higher-than-expected rate. Pure AD was uncommon, with the majority of donors with AD having multiple neurodegenerative diseases. Mapping of these diagnoses indicated that certain types of neurodegenerative diseases clustered in specific regions of the state. The results of these autopsies suggest that South Carolina has a higher-than-expected representation of early onset AD and FTLD-tau and that certain types of neurodegenerative disease cluster at specific locations. We are currently performing whole genome sequencing to determine whether specific disease-causing genetic variants contribute to these diagnostic skews.

Individuals with Down syndrome (DS) have a partial or complete trisomy of chromosome 21, resulting in an increased risk for early-onset Alzheimer's disease (AD)-type dementia by early midlife. Despite ongoing clinical trials to treat late-onset AD, individuals with DS are often excluded. Furthermore, timely diagnosis or management is often not available. Of the genetic causes of AD, people with DS represent the largest cohort. Currently, there is a knowledge gap regarding the underlying neurobiological mechanisms of DS-related AD (DS-AD), partly due to limited access to well-characterized brain tissue and biomaterials for research. To address this challenge, we created an international consortium of brain banks focused on collecting and disseminating brain tissue from persons with DS throughout their lifespan, named the Down Syndrome Biobank Consortium (DSBC) consisting of 11 biobanking sites located in Europe, India, and the USA. This perspective describes the DSBC harmonized protocols and tissue dissemination goals.

Patients with the autosomal dominant tumor susceptibility syndrome neurofibromatosis type 1 (NF1) commonly develop plexiform neurofibromas (PNs) that subsequently transform into highly aggressive malignant peripheral nerve sheath tumors (MPNSTs). Understanding the process by which a PN transforms into an MPNST would be facilitated by the availability of genetically engineered mouse (GEM) models that accurately replicate the PN-MPNST progression seen in humans with NF1. Unfortunately, GEM models with Nf1 ablation do not fully recapitulate this process. This led us to develop P0-GGFβ3 mice, a GEM model in which overexpression of the Schwann cell mitogen neuregulin-1 (NRG1) in Schwann cells results in the development of PNs that progress to become MPNSTs with high frequency. However, to determine whether tumorigenesis and neoplastic progression in P0-GGFβ3 mice accurately model the processes seen in NF1 patients, we had to first prove that the pathology of P0-GGFβ3 peripheral nerve sheath tumors recapitulates the pathology of their human counterparts. Here, we describe the specialized methodologies used to accurately diagnose and grade peripheral nervous system neoplasms in GEM models, using P0-GGFβ3 and P0-GGFβ3;Trp53+/- mice as an example. We describe the histologic, immunohistochemical, and histochemical methods used to diagnose PNs and MPNSTs, how to distinguish these neoplasms from other tumor types that mimic their pathology, and how to grade these neoplasms. We discuss the establishment of early-passage cultures from GEM MPNSTs, how to characterize these cultures using immunocytochemistry, and how to verify their tumorigenicity by establishing allografts. Collectively, these techniques characterize the pathology of PNs and MPNSTs that arise in GEM models and critically compare the pathology of these murine tumors to their human counterparts.

Malignant Peripheral Nerve Sheath Tumors (MPNSTs) are derived from Schwann cells or their precursors. In patients with the tumor susceptibility syndrome neurofibromatosis type 1 (NF1), MPNSTs are the most common malignancy and the leading cause of death. These rare and aggressive soft-tissue sarcomas offer a stark future, with 5-year disease-free survival rates of 34-60%. Treatment options for individuals with MPNSTs are disappointingly limited, with disfiguring surgery being the foremost treatment option. Many once-promising therapies such as tipifarnib, an inhibitor of Ras signaling, have failed clinically. Likewise, phase II clinical trials with erlotinib, which targets the epidermal growth factor (EFGR), and sorafenib, which targets the vascular endothelial growth factor receptor (VEGF), platelet-derived growth factor receptor (PDGF), and Raf, in combination with standard chemotherapy, have also failed to produce a response in patients. In recent years, functional genomic screening methods combined with genetic profiling of cancer cell lines have proven useful for identifying essential cytoplasmic signaling pathways and the development of target-specific therapies. In the case of rare tumor types, a variation of this approach known as cross-species comparative oncogenomics is increasingly being used to identify novel therapeutic targets. In cross-species comparative oncogenomics, genetic profiling and functional genomics are performed in genetically engineered mouse (GEM) models and the results are then validated in the rare human specimens and cell lines that are available. This paper describes how to identify candidate driver gene mutations in human and mouse MPNST cells using whole exome sequencing (WES). We then describe how to perform genome-scale shRNA screens to identify and compare critical signaling pathways in mouse and human MPNST cells and identify druggable targets in these pathways. These methodologies provide an effective approach to identifying new therapeutic targets in a variety of human cancer types.

Supplemental information which complements the manuscript data. Supplemental Figure 1. Statistical comparison of titers between human and mouse MPNST cell lines. Supplemental Figure 2. Time course of STAT1 phosphorylation in response to oHSV infection. Supplemental Figure 3. STAT1 phosphorylation in response to IFN􀉴 in human MPNST lines. Supplemental Figure 4. Effect of JAK inhibitor ruxolitinib on M201 spread. Supplemental Figure 5. Endogenous MEK/ERK activation in human MPNST lines.