Browsing by Author "Patel, Henika"
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Item Bassoon contributes to tau-seed propagation and neurotoxicity(Springer Nature, 2022) Martinez, Pablo; Patel, Henika; You, Yanwen; Jury, Nur; Perkins, Abigail; Lee-Gosselin, Audrey; Taylor, Xavier; You, Yingjian; Di Prisco, Gonzalo Viana; Huang, Xiaoqing; Dutta, Sayan; Wijeratne, Aruna B.; Redding-Ochoa, Javier; Shahid, Syed Salman; Codocedo, Juan F.; Min, Sehong; Landreth, Gary E.; Mosley, Amber L.; Wu, Yu-Chien; McKinzie, David L.; Rochet, Jean-Christophe; Zhang, Jie; Atwood, Brady K.; Troncoso, Juan; Lasagna-Reeves, Cristian A.; Anatomy, Cell Biology and Physiology, School of MedicineTau aggregation is a defining histopathological feature of Alzheimer’s disease and other tauopathies. However, the cellular mechanisms involved in tau propagation remain unclear. Here, we performed an unbiased quantitative proteomic study to identify proteins that specifically interact with this tau seed. We identified Bassoon (BSN), a presynaptic scaffolding protein, as an interactor of the tau seed isolated from a mouse model of tauopathy, and from Alzheimer’s disease and progressive supranuclear palsy postmortem samples. We show that BSN exacerbates tau seeding and toxicity in both mouse and Drosophila models for tauopathy, and that BSN downregulation decreases tau spreading and overall disease pathology, rescuing synaptic and behavioral impairments and reducing brain atrophy. Our findings improve the understanding of how tau seeds can be stabilized by interactors such as BSN. Inhibiting tau-seed interactions is a potential new therapeutic approach for neurodegenerative tauopathies.Item Evaluation of Alpha-Synuclein and Tau Antiaggregation Activity of Urea and Thiourea-Based Small Molecules for Neurodegenerative Disease Therapeutics(American Chemical Society, 2024) Ganegamage, Susantha K.; Ademoye, Taiwo A.; Patel, Henika; Alnakhala, Heba; Tripathi, Arati; Nguyen, Cuong Calvin Duc; Pham, Khai; Plascencia-Villa, Germán; Zhu, Xiongwei; Perry, George; Tian, Shiliang; Dettmer, Ulf; Lasagna-Reeves, Cristian; Fortin, Jessica S.; Anatomy, Cell Biology and Physiology, School of MedicineAlzheimer's disease (AD) and Parkinson's disease (PD) are multifactorial, chronic diseases involving neurodegeneration. According to recent studies, it is hypothesized that the intraneuronal and postsynaptic accumulation of misfolded proteins such as α-synuclein (α-syn) and tau, responsible for Lewy bodies (LB) and tangles, respectively, disrupts neuron functions. Considering the co-occurrence of α-syn and tau inclusions in the brains of patients afflicted with subtypes of dementia and LB disorders, the discovery and development of small molecules for the inhibition of α-syn and tau aggregation can be a potentially effective strategy to delay neurodegeneration. Urea is a chaotropic agent that alters protein solubilization and hydrophobic interactions and inhibits protein aggregation and precipitation. The presence of three hetero atoms (O/S and N) in proximity can coordinate with neutral, mono, or dianionic groups to form stable complexes in the biological system. Therefore, in this study, we evaluated urea and thiourea linkers with various substitutions on either side of the carbamide or thiocarbamide functionality to compare the aggregation inhibition of α-syn and tau. A thioflavin-T (ThT) fluorescence assay was used to evaluate the level of fibril formation and monitor the anti-aggregation effect of the different compounds. We opted for transmission electron microscopy (TEM) as a direct means to confirm the anti-fibrillar effect. The oligomer formation was monitored via the photoinduced cross-linking of unmodified proteins (PICUP). The anti-inclusion and anti-seeding activities of the best compounds were evaluated using M17D intracellular inclusion and biosensor cell-based assays, respectively. Disaggregation experiments were performed with amyloid plaques extracted from AD brains. The analogues with indole, benzothiazole, or N,N-dimethylphenyl on one side with halo-substituted aromatic moieties had shown less than 15% cutoff fluorescence obtained with the ThT assay. Our lead molecules 6T and 14T reduced α-syn oligomerization dose-dependently based on the PICUP assays but failed at inhibiting tau oligomer formation. The anti-inclusion effect of our lead compounds was confirmed using the M17D neuroblastoma cell model. Compounds 6T and 14T exhibited an anti-seeding effect on tau using biosensor cells. In contrast to the control, disaggregation experiments showed fewer Aβ plaques with our lead molecules (compounds 6T and 14T). Pharmacokinetics (PK) mice studies demonstrated that these two thiourea-based small molecules have the potential to cross the blood-brain barrier in rodents. Urea and thiourea linkers could be further improved for their PK parameters and studied for the anti-inclusion, anti-seeding, and disaggregation effects using transgenic mice models of neurodegenerative diseases.Item Evaluation of N- and O-Linked Indole Triazines for a Dual Effect on α-Synuclein and Tau Aggregation(American Chemical Society, 2023) Ramirez, Eduardo; Ganegamage, Susantha K.; Min, Sehong; Patel, Henika; Ogunware, Adedayo; Plascencia-Villa, Germán; Alnakhala, Heba; Shimanaka, Kazuma; Tripathi, Arati; Wang, Kuang-Wei; Zhu, Xiongwei; Rochet, Jean-Christophe; Kuo, Min-Hao; Counts, Scott E.; Perry, George; Dettmer, Ulf; Lasagna-Reeves, Cristian A.; Fortin, Jessica S.; Anatomy, Cell Biology and Physiology, School of MedicineAlzheimer's disease (AD) is the most prevalent neurodegenerative disorder underlying dementia in the geriatric population. AD manifests by two pathological hallmarks: extracellular amyloid-β (Aβ) peptide-containing senile plaques and intraneuronal neurofibrillary tangles comprised of aggregated hyperphosphorylated tau protein (p-tau). However, more than half of AD cases also display the presence of aggregated α-synuclein (α-syn)-containing Lewy bodies. Conversely, Lewy bodies disorders have been reported to have concomitant Aβ plaques and neurofibrillary tangles. Our drug discovery program focuses on the synthesis of multitarget-directed ligands to abrogate aberrant α-syn, tau (2N4R), and p-tau (1N4R) aggregation and to slow the progression of AD and related dementias. To this end, we synthesized 11 compounds with a triazine-linker and evaluated their effectiveness in reducing α-syn, tau isoform 2N4R, and p-tau isoform 1N4R aggregation. We utilized biophysical methods such as thioflavin T (ThT) fluorescence assays, transmission electron microscopy (TEM), photoinduced cross-linking of unmodified proteins (PICUP), and M17D intracellular inclusion cell-based assays to evaluate the antiaggregation properties and cellular protection of our best compounds. We also performed disaggregation assays with isolated Aβ-plaques from human AD brains. Our results demonstrated that compound 10 was effective in reducing both oligomerization and fibril formation of α-syn and tau isoform 2N4R in a dose-dependent manner via ThT and PICUP assays. Compound 10 was also effective at reducing the formation of recombinant α-syn, tau 2N4R, and p-tau 1N4R fibrils by TEM. Compound 10 reduced the development of α-syn inclusions in M17D neuroblastoma cells and stopped the seeding of tau P301S using biosensor cells. Disaggregation experiments showed smaller Aβ-plaques and less paired helical filaments with compound 10. Compound 10 may provide molecular scaffolds for further optimization and preclinical studies for neurodegenerative proteinopathies.Item Interactome Analysis of Tau‐seed Isolated from AD Brains Suggests New Mechanism for Tau Aggregation and Spreading(Wiley, 2025-01-03) Martinez, Pablo; You, Yanwen; Patel, Henika; Jury, Nur; Min, Yuhao; Redding, Javier; Huang, Xiaoqing; Dutta, Sayan; Mosley, Amber L.; Rochet, Jean-Christophe; Zhang, Jie; Ertekin-Taner, Nilüfer; Troncoso, Juan C.; Lasagna Reeves, Cristian A.; Anatomy, Cell Biology and Physiology, School of MedicineBackground: Tau aggregates, a hallmark of Alzheimer’s disease (AD) and other tauopathies, spread throughout the brain, contributing to neurodegeneration. How this propagation occurs remains elusive. Previous research suggests that tau‐seed interactors play a crucial role. Based on this, the study aimed to identify novel tau‐seed interactors in AD brains and validate their impact in vivo. Method: AD and control brain extracts were separated in fractions by Size Exclusion Chromatography. Fractions with the highest tau seeding activity, measured using a tai‐biosensor cell line, were analyzed by mass spectrometry to identify interacting proteins. Bioinformatic tools dissected enriched pathways, identifying interactors that were validated in a Drosophila tauopathy model by genetically interfering with their homologs and assessing tau accumulation and eye degeneration. Results: Tau seeding activity was concentrated in high molecular weight fractions containing only a small portion of total tau in the AD brains. Compared to controls, AD brains revealed a distinct interactome for tau‐seeds, enriched in proteins associated with synaptic and mitochondrial pathways. Notably, Drosophila screening confirmed that several novel interactors significantly reduced tau accumulation and eye degeneration, suggesting their potential therapeutic relevance. Conclusion: This study sheds light on tau propagation mechanisms in AD by identifying novel tau‐seed interactors. These interactors, particularly those involved in synaptic and mitochondrial pathways, offer promising targets for therapeutic interventions aimed at decreasing tau spread and potentially preventing neurodegeneration in tauopathies. The findings add to the growing evidence that targeting tau‐seed interactors, like previously identified BSN, could represent a novel strategy for treating these debilitating conditions.Item Pathological tau and reactive astrogliosis are associated with distinct functional deficits in a mouse model of tauopathy(Elsevier, 2022) Patel, Henika; Martinez, Pablo; Perkins, Abigail; Taylor, Xavier; Jury, Nur; McKinzie, David; Lasagna-Reeves, Cristian A.; Anatomy, Cell Biology and Physiology, School of MedicinePathological aggregation of tau and neuroinflammatory changes mark the clinical course of Alzheimer’s disease and related tauopathies. To understand the correlation between these pathological hallmarks and functional deficits, we assessed behavioral and physiological deficits in the PS19 mouse model, a broadly utilized model of tauopathy. At 9 months, PS19 mice have characteristic hyperactive behavior, a decline in motor strength, and deterioration in physiological conditions marked by lower body temperature, reduced body weight, and an increase in measures of frailty. Correlation of these deficits with different pathological hallmarks revealed that pathological tau species, characterized by soluble p-tau species, and tau seeding bioactivity correlated with impairment in grip strength and thermal regulation. On the other hand, astrocyte reactivity showed a positive correlation with the hyperactive behavior of the PS19 mice. These results suggest that a diverse spectrum of soluble pathological tau species could be responsible for different symptoms and that neuroinflammation could contribute to functional deficits independently from tau pathology. These observations enhance the necessity of a multi-targeted approach for the treatment of neurodegenerative tauopathies.Item Protein degradation impairment and synapse elimination by microglia in BSN P3866A knock‐in mouse model of tauopathy(Wiley, 2025-01-03) Patel, Henika; Martinez, Pablo; Lopes, Daniella; Jury, Nur; Vanderbosch, Katie; You, Yanwen; Kouri, Naomi; Rothberg, Darren M.; Yaguchi, Hiroaki; Tanaka, Shinya; Wakabayashi, Koichi; Yabe, Ichiro; Murray, Melissa E.; Lasagna Reeves, Cristian A.; Anatomy, Cell Biology and Physiology, School of MedicineBackground: Tau aggregation is the major cause of several neurodegenerative tauopathies. Tau interaction with other proteins affects the formation of tau aggregates with seeding activity but less is known about its effects on tau‐seed properties. Our previous study revealed that Bassoon (BSN), a presynaptic protein, interacts with tau‐seed, exacerbating its toxicity in vivo. Bsndownregulation reduced tau spreading and overall pathology. Intriguingly, a parallel study associated missense mutations in BSN with tau aggregation in patients, prompting an investigation into the influence of genetic mutations in BSN on tau pathology for potential therapeutic insights. Method: We generated a knock‐in mouse model (BSNKI) harboring the disease‐associated p.Pro3866Ala mutation in endogenous Bsn. Cognitive and motor abilities were assessed in aged heterozygous and homozygous BSNKI mice, followed by analyses of BSN and tau patterns, gliosis, and gene expression changes in their brains. Additionally, we validated our findings in a human BSN mutation carrier. Result: At 10 months, BSNKI mice displayed motor impairments on the rotarod, and grip strength assays compared to WT mice. Their brains displayed somatic BSN and pathological tau accumulation, with the gene expression changes indicating alterations in microglia activation, protein degradation pathways, complement activation, and synapse pruning. We also observed an accumulation of pathological tau at the synapses and synapse engulfment by microglia. Histopathological analyses revealed robust microglia activation and co‐deposition of proteasomal subunits with BSN. The human BSN mutation carrier displayed inclusions of BSN and tau pathology similar to observations in the BSNKI model. Conclusion: Our BSNKI mouse model, reflecting a disease‐associated BSN mutation, revealed motor impairments and pathological tau and BSN deposits, mirroring observations in BSN mutation carriers. Notably, BSN seems to play a dual role, promoting tau aggregation and sequestering protein degradation molecules, leading to tau and protein accumulation at the soma and synapse, triggering microgliosis and neuroinflammation. These findings propose BSN as a promising therapeutic target for tauopathies, underscoring the need for further exploration to elucidate underlying mechanisms and therapeutic implications.Item Protocol for the isolation and proteomic analysis of pathological tau-seeds(Elsevier, 2024) Martinez, Pablo; Patel, Henika; You, Yanwen; Doud, Emma H.; Mosley, Amber L.; Lasagna-Reeves, Cristian A.; Anatomy, Cell Biology and Physiology, School of MedicineThe aggregation and spreading of "tau-seeds" are key for the development and progression of tauopathies, including Alzheimer's disease. Here we describe the steps to isolate and analyze biochemically active tau-seeds from human, mouse, and cell origin. We detail the procedure to isolate soluble tau-seeds by size exclusion chromatography and seeding assay. The isolated tau-seed can be further analyzed to determine the interactome by mass spectrometry. This workflow identifies protein-protein interactors of tau-seeds, providing a useful tool for finding new therapeutic targets. For complete details on the use and execution of this protocol, please refer to Martinez et al.1.Item Tau ablation rescues vascular amyloid‐related deficits in a cerebral amyloid angiopathy model(Wiley, 2025-01-03) Mardones, Muriel D.; Jury, Nur; Juarez, Enrique Chimal; Patel, Henika; Martinez, Jonathan; Vanderbosch, Katie; Perkins, Abigail; Marambio, Yamil; Vidal, Ruben; Lasagna Reeves, Cristian A.; Anatomy, Cell Biology and Physiology, School of MedicineBackground: Close to 80 to 90% of subjects with AD also present cerebral amyloid angiopathy (CAA) a disease in which amyloid accumulation damages the vasculature and impairs blood flow. Since current AD therapies are targeting the disease focusing on amyloid, we are interested on determine how to decrease the accumulation of amyloid in the vasculature observed in CAA and our aim is to determine the impact of tau reduction in CAA pathogenesis. Method: We crossed the Tg‐FDD mice CAA model with Mapt‐/‐ mice to decrease tau levels and analyzed the disease pathogenesis in the different genotypes though behavioral tests, histological and morphometric assays and transcriptomic analysis using the nCounter neuroimmflamation panel from Nanostring. Result: We determined that tau ablation improved motor strength in the Tg‐FDD mice model, reduced amyloid deposition in the vasculature, decrease fibrinogen levels in the cortex, reduced astrocyte branching process associated to immunoreactivity. Nanostring analysis revealed that microglia function, oligodendrocyte and cytokine signaling are altered in the Tg‐FDD mice and that in the Tg‐FDD, Mapt ‐/‐ mice there is an increase in this mechanisms restoring the values to the ones observed in wild type mice. Conclusion: We are currently evaluating the pathways observed in the distinct inflammatory profile in microglia and oligodendrocytes. Our results suggest that tau ablation decreased CAA pathology in the Tg‐FDD mice model, which shows the potential therapeutic implications of targeting tau in CAA and related neurodegenerative diseases.