Biology subjects

Liew, J. Y.

Publications and source records attributed to Liew, J. Y..

4 recordsLinked to original sources

bioRxiv2025

Disease-specific tau polymorphs define unique protein interaction networks across proteinopathies

Tau protein aggregates exhibit distinct conformations across tauopathies, but their disease-specific protein interactions remain poorly understood. Here, we demonstrate that disease-specific tau conformations determine unique protein interaction landscapes across Alzheimers disease (AD), progressive supranuclear palsy (PSP), and dementia with Lewy bodies (DLB). Through comprehensive interactome profiling of misfolded tau aggregates from PBS- and sarkosyl-soluble fractions. We identified 493 high-confidence proteins with remarkable disease specificity--notably, no common interactors overlapping across all three tauopathies. Machine learning classification achieved compelling discrimination between diseases using as few as 4-6 proteins features, demonstrating robust molecular signatures underlying clinical heterogeneity. AD derived tau aggregates uniquely engaged cellular metabolism machinery, including key glycolytic enzymes and TCA cycle proteins, alongside glutamate/GABA neurotransmitter cycling components, with the astrocytic glutamate transporter SLC1A2 showing 27-fold enrichment over other tauopathies. In contrast, PSP tau displayed the most distinctive profile, with extensive protein depletion (52/57 significant proteins) and selective enrichment of proteasome components, particularly PSMB7 showing >3000-fold abundance. DLB tau is associated with neurogenesis modulators while depleting neuroinflammatory mediators. These interaction patterns were validated through proximity ligation assays and correlated with distinct post-translational modification profiles, with PSP tau exhibiting globally elevated ubiquitination, AD showing mixed modification patterns, and DLB displaying minimal ubiquitination. Critically, sarkosyl-soluble fractions revealed reduced interactome complexity across diseases, except for PSP tau which maintained robust interactions with GPCR-ERK signaling and kinetochore proteins, suggesting unique aggregation mechanisms. Our findings establish that conformationally distinct tau strains dictate disease-specific protein interaction networks, providing molecular insight into tauopathy diversity and identifying novel therapeutic targets for precision medicine approaches in neurodegeneration.

neuroscience↗

bioRxiv2025

Development of noninvasive imaging to measure spontaneous pain in mice

Objectively measuring pain in laboratory animals is essential for pain research and analgesic development. Despite the development of various behavioral tests to measure evoked pain in animal models, measuring spontaneous pain remains challenging. To address this unmet need, we developed a novel imaging approach to detect spontaneous nociception in animal pain models. To do this, we generated a Bacterial Artificial Chromosomes transgenic mouse that expresses Redquorin under the murine synapsin 1 promoter. Redquorin is a fusion protein consisting of chimera and a 2x tandem dimer Tomato Aequorin (tdTA), which emits long wavelength bioluminescence from activated neurons in the presence of coelenterazine. This luminescence can penetrate tissues and form a projected image on the body surface that can be detected with a spectrum In Vivo Imaging System, thus creating a Nociceptive Neuronal Activity Imaging mouse. We used the tdTA mice to image bioluminescence in the spinal regions as a surrogate of spontaneous pain induced by capsaicin, the HIV-1 envelope glycoprotein gp120, and spinal nerve ligation. Results show that Redquorin-emitted bioluminescence is a sensitive optical surrogate to measure spontaneous pain. This approach offers a new method to measure spontaneous pain in animal models for basic and translational research.

neuroscience↗

bioRxiv2025

Circulating extracellular vesicles from HIV-1 gp120-treated mice act as endogenous algogens, mediating and maintaining HIV-associated chronic pain

HIV-associated chronic pain (HIV-PAIN) remains prevalent in the post combined antiretroviral therapy era, affecting 30-60% of HIV patients worldwide. The underlying mechanism responsible for the development and maintenance of chronic pain remains unclear. gp120 is a causal factor of the HIV-PAIN and functions as an exogenous algogen. The pain experienced by human HIV-PAIN has been modeled in mice (referred to as mHIV-PAIN) using intrathecal (i.t.) injections of gp120. gp120 is a relatively short-term, static, exogenous algogen that is exhaustible in vivo. In authentic infection, HIV virions serve as the primary source of exogenous gp120, which initiates the early phase of clinical HIV-PAIN. Interestingly, while the source of replenishing gp120 decreases after antiretroviral therapy by suppressing viremia, the prevalence of chronic HIV-PAIN remains stable. To induce chronic pain in mice, gp120 needs to be repeatedly applied by the i.t. route. This raises a key question: Is an endogenous inexhaustible algogen responsible for maintaining the chronicity of HIV-PAIN? In the present study, we isolated circulating small extracellular vesicles (sEV) from mice using our mHIV-PAIN model that is i.t. injected with gp120. We refer to such sEV as gp120-sEV herein. We observed that gp120 is absent in gp120-sEV. Following transfusion of gp120-sEV intrathecally, naive recipient mice exhibit an extensive pain phenotype, including cold pain tested with we newly invented dry ice vapor cold test. RNA-sequence analysis suggests that gp120-sEVs induced expression of genes related to nociception and neuroinflammation pathways. These findings provide direct evidence that circulating sEV function as endogenous long-term "dynamic" algogens that enhance initial pain and extend the chronification of HIV-PAIN in mice, suggesting that chronic HIV-PAIN requires an exogenous algogen (gp120) paired with endogenous algogen (gp120-sEV), and that these components work synchronically to initiate and extend pain chronification. This double algogen concept provides a new insight into the pathogenesis of HIV-PAIN chronification. Our new mechanistic understanding will also assist in identifying new therapeutics to alleviate HIV-PAIN by targeting pathological gp120-sEV.

neuroscience↗

bioRxiv2023

Circulating exosomes from Alzheimer's disease suppress VE-cadherin expression and induce barrier dysfunction in recipient brain microvascular endothelial cell

BackgroundBlood-brain barrier (BBB) breakdown is a component of the progression and pathology of Alzheimers disease (AD). BBB dysfunction is primarily caused by reduced or disorganized tight junction or adherens junction proteins of brain microvascular endothelial cell (BMEC). While there is growing evidence of tight junction disruption in BMECs in AD, the functional role of adherens junctions during BBB dysfunction in AD remains unknown. Exosomes secreted from senescent cells have unique characteristics and contribute to modulating the phenotype of recipient cells. However, it remains unknown if and how these exosomes cause BMEC dysfunction in AD. ObjectivesThis study aimed to investigate the potential roles of AD circulating exosomes and their RNA cargos in brain endothelial dysfunction in AD. MethodsWe isolated exosomes from sera of five cases of AD compared with age- and sex-matched cognitively normal controls using size-exclusion chromatography technology. We validated the qualities and particle sizes of isolated exosomes with nanoparticle tracking analysis and atomic force microscopy. We measured the biomechanical natures of the endothelial barrier of BMECs, the lateral binding forces between live BMECs, using fluidic force miscopy. We visualized the paracellular expressions of the key adherens junction protein VE-cadherin in BMEC cultures and a 3D BBB model that employs primary human BMECs and pericytes with immunostaining and evaluated them using confocal microscopy. We also examined the VE-cadherin signal in brain tissues from five cases of AD and five age- and sex-matched cognitively normal controls. ResultsWe found that circulating exosomes from AD patients suppress the paracellular expression levels of VE-cadherin and impair the barrier function of recipient BMECs. Immunostaining analysis showed that AD circulating exosomes damage VE-cadherin integrity in a 3D model of microvascular tubule formation. We found that circulating exosomes in AD weaken the BBB depending on the RNA cargos. In parallel, we observed that microvascular VE-cadherin expression is diminished in AD brains compared to normal controls. ConclusionUsing in vitro and ex vivo models, our study illustrates that circulating exosomes from AD patients play a significant role in mediating the damage effect on adherens junction of recipient BMEC of the BBB in an exosomal RNA-dependent manner. This suggests a novel mechanism of peripheral senescent exosomes for AD risk.

neuroscience↗