In vivo detection of tau fibrils and amyloid β aggregates with luminescent conjugated oligothiophenes and multiphoton microscopy

Summary The detection of amyloid beta deposits and neurofibrillary tangles, both hallmarks of Alzheimer’s disease (AD), is key to understanding the mechanisms underlying these pathologies. Luminescent conjugated oligothiophenes (LCOs) enable fluorescence imaging of these protein aggregates. Using LCOs and multiphoton microscopy, individual tangles and amyloid beta deposits were labeled in vivo and imaged longitudinally in a mouse model of tauopathy and cerebral amyloidosis, respectively. Importantly, LCO HS-84, whose emission falls in the green region of the spectrum, allowed for the first time longitudinal imaging of tangle dynamics following a single intravenous injection. In addition, LCO HS-169, whose emission falls in the red region of the spectrum, successfully labeled amyloid beta deposits, allowing multiplexing with other reporters whose emission falls in the green region of the spectrum. In conclusion, this method can provide a new approach for longitudinal in vivo imaging using multiphoton microscopy of AD pathologies as well as other neurodegenerative diseases associated with protein aggregation in mouse models.

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In Vivo Imaging of Amyloid-β Deposits in Mouse Brain With Multiphoton Microscopy

Amyloid Proteins ◽

10.1385/1-59259-874-9:349 ◽

2005 ◽

pp. 349-364 ◽

Cited By ~ 3

Author(s):

Jesse Skoch ◽

Gregory A. Hickey ◽

Stephen T. Kajdasz ◽

Bradley T. Hyman ◽

Brian J. Bacskai

Keyword(s):

Mouse Brain ◽

In Vivo Imaging ◽

Multiphoton Microscopy ◽

Amyloid Β

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Transcranial in vivo detection of amyloid-beta at single plaque resolution with large-field multifocal illumination fluorescence microscopy

10.1101/2020.02.01.929844 ◽

2020 ◽

Cited By ~ 2

Author(s):

Ruiqing Ni ◽

Zhenyue Chen ◽

Gloria Shi ◽

Alessia Villois ◽

Quanyu Zhou ◽

...

Keyword(s):

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Fluorescence Microscopy ◽

Amyloid Beta ◽

Large Field ◽

Microscopy Technique ◽

In Vivo Detection ◽

Amyloid Deposits ◽

Microscopy Techniques

AbstractThe abnormal deposition of beta-amyloid proteins in the brain is one of the major histopathological hallmarks of Alzheimer’s disease. Currently available intravital microscopy techniques for high-resolution plaque visualization commonly involve highly invasive procedures and are limited to a small field-of-view within the rodent brain. Here, we report the transcranial detection of amyloid-beta deposits at the whole brain scale with 20 μm resolution in APP/PS1 and arcAβ mouse models of Alzheimer’s disease amyloidosis using a large-field multifocal (LMI) fluorescence microscopy technique. Highly sensitive and specific detection of amyloid-beta deposits at a single plaque level in APP/PS1 and arcAβ mice was facilitated using luminescent conjugated oligothiophene HS-169. Immunohistochemical staining with HS-169, anti-Aβ antibody 6E10, and conformation antibodies OC (fibrillar) of brain tissue sections further showed that HS-169 resolved compact parenchymal and vessel-associated amyloid deposits. The novel imaging platform offers new prospects for in vivo studies into Alzheimer’s disease mechanisms in animal models as well as longitudinal monitoring of therapeutic responses at a single plaque level.

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Imaging Amyloid-β Deposits In Vivo

Journal of Cerebral Blood Flow & Metabolism ◽

10.1097/00004647-200209000-00001 ◽

2002 ◽

Vol 22 (9) ◽

pp. 1035-1041 ◽

Cited By ~ 76

Author(s):

Brian J. Bacskai ◽

William E. Klunk ◽

Chester A. Mathis ◽

Bradley T. Hyman

Keyword(s):

Single Photon ◽

Senile Plaques ◽

Photon Emission ◽

Multiphoton Microscopy ◽

Amyloid Β ◽

Neuronal Loss ◽

High Sensitivity ◽

Emission Computed Tomography ◽

Tissue Samples

Alzheimer disease (AD) is an illness that can only be diagnosed with certainty with postmortem examination of brain tissue. Tissue samples from afflicted patients show neuronal loss, neurofibrillary tangles (NFTs), and amyloid-β plaques. An imaging technique that permitted in vivo detection of NFTs or amyloid-β plaques would be extremely valuable. For example, chronic imaging of senile plaques would provide a readout of the efficacy of experimental therapeutics aimed at removing these neuropathologic lesions. This review discusses the available techniques for imaging amyloid-β deposits in the intact brain, including magnetic resonance imaging, positron emission tomography, single photon emission computed tomography, and multiphoton microscopy. A variety of agents that target amyloid-β deposits specifically have been developed using one or several of these imaging modalities. The difficulty in developing these tools lies in the need for the agents to cross the blood-brain barrier while recognizing amyloid-β with high sensitivity and specificity. This review describes the progress in developing reagents suitable for in vivo imaging of senile plaques.

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In Vivo Imaging of Alzheimer Pathology in Transgenic Mice using Multiphoton Microscopy

The Living Brain and Alzheimer’s Disease ◽

10.1007/978-3-642-59300-0_4 ◽

2004 ◽

pp. 33-45

Author(s):

Brian J. Bacskai ◽

William E. Klunk ◽

Gregory A. Hickey ◽

Jesse Skoch ◽

Stephen T. Kajdasz ◽

...

Keyword(s):

Transgenic Mice ◽

In Vivo Imaging ◽

Multiphoton Microscopy ◽

Alzheimer Pathology

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Real-Time In Vivo Imaging Reveals the Ability of Monocytes to Clear Vascular Amyloid Beta

Cell Reports ◽

10.1016/j.celrep.2013.10.010 ◽

2013 ◽

Vol 5 (3) ◽

pp. 646-653 ◽

Cited By ~ 120

Author(s):

Jean-Philippe Michaud ◽

Marc-André Bellavance ◽

Paul Préfontaine ◽

Serge Rivest

Keyword(s):

Real Time ◽

Amyloid Beta ◽

In Vivo Imaging

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Altered Amyloid-β Metabolism and Deposition in Genomic-based β-Secretase Transgenic Mice

Journal of Biological Chemistry ◽

10.1074/jbc.m409680200 ◽

2004 ◽

Vol 279 (50) ◽

pp. 52535-52542 ◽

Cited By ~ 30

Author(s):

Matthew J. Chiocco ◽

Laura Shapiro Kulnane ◽

Linda Younkin ◽

Steve Younkin ◽

Geneviève Evin ◽

...

Keyword(s):

Transgenic Mice ◽

Senile Plaques ◽

Amyloid Β ◽

Transgenic Animals ◽

Brain Regions ◽

Primary Component ◽

App Processing ◽

Bace1 Expression ◽

First Time

Amyloid-β (Aβ) the primary component of the senile plaques found in Alzheimer's disease (AD) is generated by the rate-limiting cleavage of amyloid precursor protein (APP) by β-secretase followed by γ-secretase cleavage. Identification of the primary β-secretase gene,BACE1, provides a unique opportunity to examine the role this unique aspartyl protease plays in altering Aβ metabolism and deposition that occurs in AD. The current experiments seek to examine how modulating β-secretase expression and activity alters APP processing and Aβ metabolismin vivo. Genomic-basedBACE1transgenic mice were generated that overexpress humanBACE1mRNA and protein. The highest expressingBACE1transgenic line was mated to transgenic mice containing human APP transgenes. Our biochemical and histochemical studies demonstrate that mice overexpressing bothBACE1andAPPshow specific alterations in APP processing and age-dependent Aβ deposition. We observed elevated levels of Aβ isoforms as well as significant increases of Aβ deposits in these double transgenic animals. In particular, the double transgenics exhibited a unique cortical deposition profile, which is consistent with a significant increase of BACE1 expression in the cortex relative to other brain regions. Elevated BACE1 expression coupled with increased deposition provides functional evidence for β-secretase as a primary effector in regional amyloid deposition in the AD brain. Our studies demonstrate, for the first time, that modulation ofBACE1activity may play a significant role in AD pathogenesisin vivo.

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Neutrophil mobilization via plerixafor-mediated CXCR4 inhibition arises from lung demargination and blockade of neutrophil homing to the bone marrow

Journal of Experimental Medicine ◽

10.1084/jem.20130056 ◽

2013 ◽

Vol 210 (11) ◽

pp. 2321-2336 ◽

Cited By ~ 120

Author(s):

Sapna Devi ◽

Yilin Wang ◽

Weng Keong Chew ◽

Ronald Lima ◽

Noelia A-González ◽

...

Keyword(s):

Bone Marrow ◽

Host Defense ◽

Multiphoton Microscopy ◽

Blood Neutrophil ◽

Cxcr4 Antagonist ◽

Treatment Regimens ◽

Blood Neutrophils ◽

Neutropenic Patients ◽

First Time

Blood neutrophil homeostasis is essential for successful host defense against invading pathogens. Circulating neutrophil counts are positively regulated by CXCR2 signaling and negatively regulated by the CXCR4–CXCL12 axis. In particular, G-CSF, a known CXCR2 signaler, and plerixafor, a CXCR4 antagonist, have both been shown to correct neutropenia in human patients. G-CSF directly induces neutrophil mobilization from the bone marrow (BM) into the blood, but the mechanisms underlying plerixafor-induced neutrophilia remain poorly defined. Using a combination of intravital multiphoton microscopy, genetically modified mice and novel in vivo homing assays, we demonstrate that G-CSF and plerixafor work through distinct mechanisms. In contrast to G-CSF, CXCR4 inhibition via plerixafor does not result in neutrophil mobilization from the BM. Instead, plerixafor augments the frequency of circulating neutrophils through their release from the marginated pool present in the lung, while simultaneously preventing neutrophil return to the BM. Our study demonstrates for the first time that drastic changes in blood neutrophils can originate from alternative reservoirs other than the BM, while implicating a role for CXCR4–CXCL12 interactions in regulating lung neutrophil margination. Collectively, our data provides valuable insights into the fundamental regulation of neutrophil homeostasis, which may lead to the development of improved treatment regimens for neutropenic patients.

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