In vivo imaging of amyloid-beta deposits in mouse brain with multiphoton microscopy.
ABSTRACT With the advent of transgenic mouse models expressing cortical amyloid pathology, the potential to study its progression in an intact brain has been realized. Multiphoton microscopy provides a non-destructive means of imaging with micron resolution up to 500 microm deep into the cortex. We detail a surgical procedure and discuss a multiphoton imaging approach that allows for labeling and chronic visualization of amyloid-beta deposits through a cranial window. The ability to monitor these hallmarks of Alzheimer's disease enables studies aimed at evaluating the efficacy of treatment and prevention strategies.
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ABSTRACT: Cellular interactions with extracellular matrices (ECM) through the application of mechanical forces mediate numerous biological processes including developmental morphogenesis, wound healing and cancer metastasis. They also play a key role in the cellular repopulation and/or remodeling of engineered tissues and organs. While 2-D studies can provide important insights into many aspects of cellular mechanobiology, cells reside within 3-D ECMs in vivo, and matrix structure and dimensionality have been shown to impact cell morphology, protein organization and mechanical behavior. Global measurements of cell-induced compaction of 3-D collagen matrices can provide important insights into the regulation of overall cell contractility by various cytokines and signaling pathways. However, to understand how the mechanics of cell spreading, migration, contraction and matrix remodeling are regulated at the molecular level, these processes must also be studied in individual cells. Here we review the evolution and application of techniques for imaging and assessing local cell-matrix mechanical interactions in 3-D culture models, tissue explants and living animals.Experimental Cell Research 06/2013; 319(16). DOI:10.1016/j.yexcr.2013.06.018 · 3.37 Impact Factor
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ABSTRACT: Increased intracellular levels of α-synuclein are implicated in Parkinson's disease and related disorders and may be caused by alterations in the ubiquitin-proteasome system (UPS) or the autophagy-lysosomal pathway (ALP). A critical question remains how α-synuclein is degraded by neurons in vivo. To address this, our study uses α-synuclein transgenic mice, expressing human α-synuclein or α-synuclein-eGFP under the (h)PDGF-β promoter, in combination with in vivo pharmacologic and multiphoton imaging strategies to systematically test degradation pathways in the living mouse brain. We demonstrate that the UPS is the main degradation pathway for α-synuclein under normal conditions in vivo while with increased α-synuclein burden the ALP is recruited. Moreover, we report alterations of the UPS in α-synuclein transgenic mice and age dependence to the role of the UPS in α-synuclein degradation. In addition, we provide evidence that the UPS and ALP might be functionally connected such that impairment of one can upregulate the other. These results provide a novel link between the UPS, the ALP, and α-synuclein pathology and may have important implications for future therapeutics targeting degradation pathways.The Journal of Neuroscience : The Official Journal of the Society for Neuroscience 10/2011; 31(41):14508-20. DOI:10.1523/JNEUROSCI.1560-11.2011 · 6.75 Impact Factor
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ABSTRACT: Amyloid-beta (Abeta) deposition is a defining feature of Alzheimer's disease (AD). The toxicity of Abeta aggregation is thought to contribute to clinical deficits including progressive memory loss and cognitive dysfunction. Therefore, Abeta peptide has become the focus of many therapeutic approaches for the treatment of AD due to its central role in the development of neuropathology of AD. In the past decade, taking the advantage of multiphoton microscopy and molecular probes for amyloid peptide labeling, the dynamic progression of Abeta aggregation in amyloid plaques and cerebral amyloid angiopathy has been monitored in real time in transgenic mouse models of AD. Moreover, amyloid plaque-associated alterations in the brain including dendritic and synaptic abnormalities, changes of neuronal and astrocytic calcium homeostasis, microglial activation and recruitment in the plaque location have been extensively studied. These studies provide remarkable insight to understand the pathogenesis and pathogenicity of amyloid plaques in the context of AD. The ability to longitudinally image plaques and related structures facilitates the evaluation of therapeutic approaches targeting toward the clearance of plaques.Neuropharmacology 09/2010; 59(4-5):268-75. DOI:10.1016/j.neuropharm.2010.04.007 · 4.82 Impact Factor