IU Indianapolis ScholarWorks :: Browsing by Author "Wilcock, Donna M."

Browsing by Author "Wilcock, Donna M."

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A high-throughput single-cell RNA expression profiling method identifies human pericyte markers
(Wiley, 2023) Sziraki, Andras; Zhong, Yu; Neltner, Allison M.; Niedowicz, Dana; Rogers, Colin B.; Wilcock, Donna M.; Nehra, Geetika; Neltner, Janna H.; Smith, Rebecca R.; Hartz, Anika M.; Cao, Junyue; Nelson, Peter T.; Neurology, School of Medicine
Aims: We sought to identify and optimise a universally available histological marker for pericytes in the human brain. Such a marker could be a useful tool for researchers. Further, identifying a gene expressed relatively specifically in human pericytes could provide new insights into the biological functions of this fascinating cell type. Methods: We analysed single-cell RNA expression profiles derived from different human and mouse brain regions using a high-throughput and low-cost single-cell transcriptome sequencing method called EasySci. Through this analysis, we were able to identify specific gene markers for pericytes, some of which had not been previously characterised. We then used commercially (and therefore universally) available antibodies to immunolabel the pericyte-specific gene products in formalin-fixed paraffin-embedded (FFPE) human brains and also performed immunoblots to determine whether appropriately sized proteins were recognised. Results: In the EasySci data sets, highly pericyte-enriched expression was notable for SLC6A12 and SLC19A1. Antibodies against these proteins recognised bands of approximately the correct size in immunoblots of human brain extracts. Following optimisation of the immunohistochemical technique, staining for both antibodies was strongly positive in small blood vessels and was far more effective than a PDGFRB antibody at staining pericyte-like cells in FFPE human brain sections. In an exploratory sample of other human organs (kidney, lung, liver, muscle), immunohistochemistry did not show the same pericyte-like pattern of staining. Conclusions: The SLC6A12 antibody was well suited for labelling pericytes in human FFPE brain sections, based on the combined results of single-cell RNA-seq analyses, immunoblots and immunohistochemical studies.
A pathway linking pulse pressure to dementia in adults with Down syndrome
(Oxford University Press, 2024-05-09) Rizvi, Batool; Lao, Patrick J.; Sathishkumar, Mithra; Taylor, Lisa; Queder, Nazek; McMillan, Liv; Edwards, Natalie C.; Keator, David B.; Doran, Eric; Hom, Christy; Nguyen, Dana; Rosas, H. Diana; Lai, Florence; Schupf, Nicole; Gutierrez, Jose; Silverman, Wayne; Lott, Ira T.; Mapstone, Mark; Wilcock, Donna M.; Head, Elizabeth; Yassa, Michael A.; Brickman, Adam M.; Neurology, School of Medicine
Adults with Down syndrome are less likely to have hypertension than neurotypical adults. However, whether blood pressure measures are associated with brain health and clinical outcomes in this population has not been studied in detail. Here, we assessed whether pulse pressure is associated with markers of cerebrovascular disease and is linked to a diagnosis of dementia in adults with Down syndrome via structural imaging markers of cerebrovascular disease and atrophy. The study included participants with Down syndrome from the Alzheimer’s Disease - Down Syndrome study (n = 195, age = 50.6 ± 7.2 years, 44% women, 18% diagnosed with dementia). Higher pulse pressure was associated with greater global, parietal and occipital white matter hyperintensity volume but not with enlarged perivascular spaces, microbleeds or infarcts. Using a structural equation model, we found that pulse pressure was associated with greater white matter hyperintensity volume, which in turn was related to increased neurodegeneration, and subsequent dementia diagnosis. Pulse pressure is an important determinant of brain health and clinical outcomes in individuals with Down syndrome despite the low likelihood of frank hypertension.
Acute Communication Between Microglia and Nonparenchymal Immune Cells in the Anti-Aβ Antibody-Injected Cortex
(Society for Neuroscience, 2025-01-29) Foley, Kate E.; Weekman, Erica M.; Krick, Katelynn E.; Johnson, Sherika N.; Sudduth, Tiffany L.; Wilcock, Donna M.; Neurology, School of Medicine
Anti-Aβ immunotherapy use to treat Alzheimer's disease is on the rise. While anti-Aβ antibodies provide hope in targeting Aβ plaques in the brain, there still remains a lack of understanding regarding the cellular responses to these antibodies in the brain. In this study, we sought to identify the acute effects of anti-Aβ antibodies on immune responses. To determine cellular changes due to anti-Aβ antibody exposure, we intracranially injected 14 mo APP male and female mice with anti-Aβ IgG1 (6E10) or control IgG1 into the cortex. After 24 h or 3 d, we harvested the cortex and performed a glial cell-enriched preparation for single-cell sequencing. Cell types, proportions, and cell-to-cell signaling were evaluated between the two injection conditions and two acute timepoints. We identified 23 unique cell clusters including microglia, astrocytes, endothelial cells, neurons, oligos/OPCs, immune cells, and unknown. The anti-Aβ antibody-injected cortices revealed more ligand-receptor (L-R) communications between cell types, as well as stronger communications at only 24 h. At 3 d, while there were more L-R communications for the anti-Aβ antibody condition, the strength of these connections was stronger in the control IgG condition. We also found evidence of an initial and strong communication emphasis in microglia-to-nonparenchymal immune cells at 24 h, specifically in the TGFβ signaling pathway. We identify several pathways that are specific to anti-Aβ antibody exposure at acute timepoints. These data lay the groundwork for understanding the brain's unique response to anti-Aβ antibodies.
Acute communication between microglia and other immune cells in the anti‐Aβ antibody injected cortex
(Wiley, 2025-01-03) Foley, Kate E.; Krick, Katelynn E.; Weekman, Erica M.; Wilcock, Donna M.; Neurology, School of Medicine
Background: Anti‐Aβ immunotherapy use to treat Alzheimer’s disease is on the rise. While anti‐Aβ antibodies provide hope in targeting Aβ plaques in the brain, a major side effect of amyloid‐related imaging abnormalities (ARIA) persists with no known cause. As severe ARIA is typically seen within the first few infusions in human clinical trials, we sought to identify acute effects of anti‐Aβ antibody on brain. Method: To determine cellular changes due to anti‐Aβ antibody exposure, we intracranially injected 14mo APP male and female mice with anti‐Aβ IgG1 (6E10) or control IgG1 into the cortex. After 24hrs or 3days, we harvested the cortex and performed a glial cell enriched preparation for single cell sequencing. Cell types, proportions, and cell‐to‐cell signaling was evaluated between the two injection conditions and two acute timepoints. Result: We identified 23 unique cell clusters including microglia, astrocytes, endothelial cells, neurons, oligos/OPCs, immune cells, and unknown. The anti‐Aβ antibody injected cortices revealed more ligand‐receptor communications between cell types, as well as stronger communications at 24hrs. At 3days, while there were more L‐R communications for the anti‐Aβ antibody condition, the strength of these connections was stronger in the control IgG condition. Specific pathways such as CD48 and PD‐L1 were enriched in the anti‐Aβ antibody condition, but not the control IgG condition in microglia‐to‐microglia communication. We also found evidence of an initial and strong communication emphasis in microglia‐to‐peripheral immune cells at 24hrs, specifically in the TGFβ signaling pathway. Additionally, we found that peripheral immune cells that were exposed to anti‐Aβ antibody failed to signal via the TNF pathway, which was strongly enriched in the control IgG condition at both timepoints. Conclusion: We identify several pathways that differ between anti‐Aβ antibody and control IgG injections at acute timepoints. These data lay the groundwork for understanding the brain’s unique response to anti‐Aβ antibody and its predisposition to ARIA.
Advancements in Immunity and Dementia Research: Highlights from the 2023 AAIC Advancements: Immunity Conference
(Wiley, 2025) Kloske, Courtney M.; Mahinrad, Simin; Barnum, Christopher J.; Batista, Andre F.; Bradshaw, Elizabeth M.; Butts, Brittany; Carrillo, Maria C.; Chakrabarty, Paramita; Chen, Xiaoying; Craft, Suzanne; Da Mesquita, Sandro; Dabin, Luke C.; Devanand, Davangere; Duran-Laforet, Violeta; Elyaman, Wassim; Evans, Elizabeth E.; Fitzgerald-Bocarsly, Patricia; Foley, Kate E.; Harms, Ashley S.; Heneka, Michael T.; Hong, Soyon; Huang, Yu-Wen A.; Jackvony, Stephanie; Lai, Laijun; Le Guen, Yann; Lemere, Cynthia A.; Liddelow, Shane A.; Martin-Peña, Alfonso; Orr, Anna G.; Quintana, Francisco J.; Ramey, Grace D.; Rexach, Jessica E.; Rizzo, Stacey J. S.; Sexton, Claire; Tang, Alice S.; Torrellas, Jose G.; Tsai, Andy P.; van Olst, Lynn; Walker, Keenan A.; Wharton, Whitney; Tansey, Malú Gámez; Wilcock, Donna M.; Medical and Molecular Genetics, School of Medicine
The immune system is a key player in the onset and progression of neurodegenerative disorders. While brain resident immune cell-mediated neuroinflammation and peripheral immune cell (eg, T cell) infiltration into the brain have been shown to significantly contribute to Alzheimer's disease (AD) pathology, the nature and extent of immune responses in the brain in the context of AD and related dementias (ADRD) remain unclear. Furthermore, the roles of the peripheral immune system in driving ADRD pathology remain incompletely elucidated. In March of 2023, the Alzheimer's Association convened the Alzheimer's Association International Conference (AAIC), Advancements: Immunity, to discuss the roles of the immune system in ADRD. A wide range of topics were discussed, such as animal models that replicate human pathology, immune-related biomarkers and clinical trials, and lessons from other fields describing immune responses in neurodegeneration. This manuscript presents highlights from the conference and outlines avenues for future research on the roles of immunity in neurodegenerative disorders. HIGHLIGHTS: The immune system plays a central role in the pathogenesis of Alzheimer's disease. The immune system exerts numerous effects throughout the brain on amyloid-beta, tau, and other pathways. The 2023 AAIC, Advancements: Immunity, encouraged discussions and collaborations on understanding the role of the immune system.
Alzheimer's disease and inflammatory biomarkers positively correlate in plasma in the UK‐ADRC cohort
(Wiley, 2024) Foley, Kate E.; Winder, Zachary; Sudduth, Tiffany L.; Martin, Barbara J.; Nelson, Peter T.; Jicha, Gregory A.; Harp, Jordan P.; Weekman, Erica M.; Wilcock, Donna M.; Neurology, School of Medicine
Introduction: Protein-based plasma assays provide hope for improving accessibility and specificity of molecular diagnostics to diagnose dementia. Methods: Plasma was obtained from participants (N = 837) in our community-based University of Kentucky Alzheimer's Disease Research Center cohort. We evaluated six Alzheimer's disease (AD)- and neurodegeneration-related (Aβ40, Aβ42, Aβ42/40, p-tau181, total tau, and NfLight) and five inflammatory biomarkers (TNF𝛼, IL6, IL8, IL10, and GFAP) using the SIMOA-based protein assay platform. Statistics were performed to assess correlations. Results: Our large cohort reflects previous plasma biomarker findings. Relationships between biomarkers to understand AD-inflammatory biomarker correlations showed significant associations between AD and inflammatory biomarkers suggesting peripheral inflammatory interactions with increasing AD pathology. Biomarker associations parsed out by clinical diagnosis (normal, MCI, and dementia) reveal changes in strength of the correlations across the cognitive continuum. Discussion: Unique AD-inflammatory biomarker correlations in a community-based cohort reveal a new avenue for utilizing plasma-based biomarkers in the assessment of AD and related dementias. Highlights: Large community cohorts studying sex, age, and APOE genotype effects on biomarkers are few. It is unknown how biomarker-biomarker associations vary through aging and dementia. Six AD (Aβ40, Aβ42, Aβ42/40, p-tau181, total tau, and NfLight) and five inflammatory biomarkers (TNFα, IL6, IL8, IL10, and GFAP) were used to examine associations between biomarkers. Plasma biomarkers suggesting increasing cerebral AD pathology corresponded to increases in peripheral inflammatory markers, both pro-inflammatory and anti-inflammatory. Strength of correlations, between pairs of classic AD and inflammatory plasma biomarker, changes throughout cognitive progression to dementia.
Atorvastatin rescues hyperhomocysteinemia-induced cognitive deficits and neuroinflammatory gene changes
(BMC, 2023-09-01) Weekman, Erica M.; Johnson, Sherika N.; Rogers, Colin B.; Sudduth, Tiffany L.; Xie, Kevin; Qiao, Qi; Fardo, David W.; Bottiglieri, Teodoro; Wilcock, Donna M.; Neurology, School of Medicine
Background: Epidemiological data suggests statins could reduce the risk of dementia, and more specifically, Alzheimer's disease (AD). Pre-clinical data suggests statins reduce the risk of dementia through their pleiotropic effects rather than their cholesterol lowering effects. While AD is a leading cause of dementia, it is frequently found co-morbidly with cerebral small vessel disease and other vascular contributions to cognitive impairment and dementia (VCID), which are another leading cause of dementia. In this study, we determined if atorvastatin ameliorated hyperhomocysteinemia (HHcy)-induced VCID. Methods: Wild-type (C57Bl6/J) mice were placed on a diet to induce HHcy or a control diet each with or without atorvastatin for 14 weeks. Mice underwent novel object recognition testing before tissue collection. Plasma total cholesterol and total homocysteine as well as related metabolites were measured. Using qPCR and NanoString technology, we profiled glial cell-associated gene expression changes. Finally, microglial morphology, astrocyte end feet, and microhemorrhages were analyzed using histological methods. Results: Atorvastatin treatment of HHcy in mice led to no changes in total cholesterol but decreases in total homocysteine in plasma. While HHcy decreased expression of many glial genes, atorvastatin rescued these gene changes, which mostly occurred in oligodendrocytes and microglia. Microglia in HHcy mice with atorvastatin were trending towards fewer processes compared to control with atorvastatin, but there were no atorvastatin effects on astrocyte end feet. While atorvastatin treatment was trending towards increasing the area of microhemorrhages in HHcy mice in the frontal cortex, it only slightly (non-significantly) reduced the number of microhemorrhages. Finally, atorvastatin treatment in HHcy mice led to improved cognition on the novel object recognition task. Conclusions: These data suggest that atorvastatin rescued cognitive changes induced by HHcy most likely through lowering plasma total homocysteine and rescuing gene expression changes rather than impacts on vascular integrity or microglial changes.
Cerebrovascular disease drives Alzheimer plasma biomarker concentrations in adults with Down syndrome
(medRxiv, 2023-11-30) Edwards, Natalie C.; Lao, Patrick J.; Alshikho, Mohamad J.; Ericsson, Olivia M.; Rizvi, Batool; Petersen, Melissa E.; O’Bryant, Sid; Flores-Aguilar, Lisi; Simoes, Sabrina; Mapstone, Mark; Tudorascu, Dana L.; Janelidze, Shorena; Hansson, Oskar; Handen, Benjamin L.; Christian, Bradley T.; Lee, Joseph H.; Lai, Florence; Rosas, H. Diana; Zaman, Shahid; Lott, Ira T.; Yassa, Michael A.; Gutierrez, José; Wilcock, Donna M.; Head, Elizabeth; Brickman, Adam M.; Neurology, School of Medicine
Importance: By age 40 years over 90% of adults with Down syndrome (DS) have Alzheimer's disease (AD) pathology and most progress to dementia. Despite having few systemic vascular risk factors, individuals with DS have elevated cerebrovascular disease (CVD) markers that track with the clinical progression of AD, suggesting a role for CVD that is hypothesized to be mediated by inflammatory factors. Objective: To examine the pathways through which small vessel CVD contributes to AD-related pathophysiology and neurodegeneration in adults with DS. Design: Cross sectional analysis of neuroimaging, plasma, and clinical data. Setting: Participants were enrolled in Alzheimer's Biomarker Consortium - Down Syndrome (ABC-DS), a multisite study of AD in adults with DS. Participants: One hundred eighty-five participants (mean [SD] age=45.2 [9.3] years) with available MRI and plasma biomarker data were included. White matter hyperintensity (WMH) volumes were derived from T2-weighted FLAIR MRI scans and plasma biomarker concentrations of amyloid beta (Aβ42/Aβ40), phosphorylated tau (p-tau217), astrocytosis (glial fibrillary acidic protein, GFAP), and neurodegeneration (neurofilament light chain, NfL) were measured with ultrasensitive immunoassays. Main outcomes and measures: We examined the bivariate relationships of WMH, Aβ42/Aβ40, p-tau217, and GFAP with age-residualized NfL across AD diagnostic groups. A series of mediation and path analyses examined causal pathways linking WMH and AD pathophysiology to promote neurodegeneration in the total sample and groups stratified by clinical diagnosis. Results: There was a direct and indirect bidirectional effect through GFAP of WMH on p-tau217 concentration, which was associated with NfL concentration in the entire sample. Among cognitively stable participants, WMH was directly and indirectly, through GFAP, associated with p-tau217 concentration, and in those with MCI, there was a direct effect of WMH on p-tau217 and NfL concentrations. There were no associations of WMH with biomarker concentrations among those diagnosed with dementia. Conclusions and relevance: The findings suggest that among individuals with DS, CVD promotes neurodegeneration by increasing astrocytosis and tau pathophysiology in the presymptomatic phases of AD. This work joins an emerging literature that implicates CVD and its interface with neuroinflammation as a core pathological feature of AD in adults with DS.
Cerebrovascular disease is associated with Alzheimer's plasma biomarker concentrations in adults with Down syndrome
(Oxford University Press, 2024-09-25) Edwards, Natalie C.; Lao, Patrick J.; Alshikho, Mohamad J.; Ericsson, Olivia M.; Rizvi, Batool; Petersen, Melissa E.; O’Bryant, Sid; Flores Aguilar, Lisi; Simoes, Sabrina; Mapstone, Mark; Tudorascu, Dana L.; Janelidze, Shorena; Hansson, Oskar; Handen, Benjamin L.; Christian, Bradley T.; Lee, Joseph H.; Lai, Florence; Rosas, H. Diana; Zaman, Shahid; Lott, Ira T.; Yassa, Michael A.; Alzheimer’s Biomarkers Consortium–Down Syndrome (ABC-DS) Investigators; Gutierrez, José; Wilcock, Donna M.; Head, Elizabeth; Brickman, Adam M.; Neurology, School of Medicine
By age 40 years, over 90% of adults with Down syndrome have Alzheimer's disease pathology and most progress to dementia. Despite having few systemic vascular risk factors, individuals with Down syndrome have elevated cerebrovascular disease markers that track with the clinical progression of Alzheimer's disease, suggesting a role of cerebrovascular disease that is hypothesized to be mediated by inflammatory factors. This study examined the pathways through which small vessel cerebrovascular disease contributes to Alzheimer's disease-related pathophysiology and neurodegeneration in adults with Down syndrome. One hundred eighty-five participants from the Alzheimer's Biomarkers Consortium-Down Syndrome [mean (SD) age = 45.2 (9.3) years] with available MRI and plasma biomarker data were included in this study. White matter hyperintensity (WMH) volumes were derived from T2-weighted fluid-attenuated inversion recovery MRI scans, and plasma biomarker concentrations of amyloid beta 42/40, phosphorylated tau 217, astrocytosis (glial fibrillary acidic protein) and neurodegeneration (neurofilament light chain) were measured with ultrasensitive immunoassays. We examined the bivariate relationships of WMH, amyloid beta 42/40, phosphorylated tau 217 and glial fibrillary acidic protein with age-residualized neurofilament light chain across Alzheimer's disease diagnostic groups. A series of mediation and path analyses examined statistical pathways linking WMH and Alzheimer's disease pathophysiology to promote neurodegeneration in the total sample and groups stratified by clinical diagnosis. There was a direct and indirect bidirectional effect through the glial fibrillary acidic protein of WMH on phosphorylated tau 217 concentration, which was associated with neurofilament light chain concentration in the entire sample. Amongst cognitively stable participants, WMH was directly and indirectly, through glial fibrillary acidic protein, associated with phosphorylated tau 217 concentration, and in those with mild cognitive impairment, there was a direct effect of WMH on phosphorylated tau 217 and neurofilament light chain concentrations. There were no associations of WMH with biomarker concentrations among those diagnosed with dementia. The findings from this cross-sectional study suggest that among individuals with Down syndrome, cerebrovascular disease promotes neurodegeneration by increasing astrocytosis and tau pathophysiology in the presymptomatic phases of Alzheimer's disease, but future studies will need to confirm these associations with longitudinal data. This work joins an emerging literature that implicates cerebrovascular disease and its interface with neuroinflammation as a core pathological feature of Alzheimer's disease in adults with Down syndrome.
Cerebrovascular pathology and neurovascular coupling impairment in aged‐mouse model of Alzheimer’s disease
(Wiley, 2025-01-09) Promkan, Moltira; Phikulthong, Kamonchat; Kimseng, Rungruedee; Pauss, Kate; Lee, Tiffany; Weekman, Erica M.; Nelson, Peter T.; Wilcock, Donna M.; Sompol, Pradoldej; Neurology, School of Medicine
Background: Vascular pathology profoundly comorbid with AD pathology could worsen disease progression and reduce treatment efficacy. Knowledge of small vessels and cerebrovascular function in AD mouse models is limited. Investigating vascular related aspects for preclinical AD studies is essential for biomarker development and treatment trials. Therefore, we aim to characterize cerebrovascular amyloid angiopathy (CAA), vascular degeneration, and cerebrovascular function in an aged Tg2576 mouse model of AD. Method: WT and Tg2576 (∼ 2 years of age) were housed in a reversed light cycle room. Cranial window surgery and cranial window installation were performed. After 3 weeks of recovery, the animals were acclimated to an intravital multiphoton imaging platform. To visualize beta‐amyloid in the brain, Methoxy‐X04 (10mg/kg) was injected the day before the imaging. Cerebrovasculature was visualized by intravascular retro‐orbital injection of rhodamine‐dextran (5% V/W in saline). This procedure was done while the animals were under anesthesia and securely head‐fixed prior to the imaging. Z‐stack imaging was performed, and vascular structure was analyzed by using FIJI or ImageJ. Neurovascular coupling was performed to investigate vascular function in awake mice. While imaging penetrating arteriole, air‐puff stimulation of contralateral whiskers was conducted and increased vascular diameter is used as an indicator of hyperemic neurovascular function. Result: Investigation of cerebrovascular pathology including CAA, vascular straightness, and vascular blebbing are ongoing. During whisker stimulation, vascular diameter was relatively reduced in Tg2576 compared to WT control mice. Conclusion: Aged Tg2576 exhibits comorbidity of amyloid plaques, cerebral amyloid angiopathy, small vessel pathology and cerebrovascular dysfunction similar to human brain. This aged Tg2576 could be used as a preclinical translational mixed vascular/AD model.

Browsing by Author "Wilcock, Donna M."

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