In Situ Fluorescence Imaging of Myelination

Wang, Changning; Popescu, Daniela C.; Wu, Chunying; Zhu, Junqing; Macklin, Wendy B.; Wang, Yanming

doi:10.1369/jhc.2010.954842

Cited by 54 publications

(49 citation statements)

References 20 publications

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“…Our previous structure-activity relationship studies of coumarin derivatives led us to identify a lead compound, named Case Imaging Compound (CMC), which readily crosses the BBB and selectively binds to myelin sheaths in vivo. 17 We found that the structure of CMC can be selectively modified without adversely affecting its binding affinity and specificity for myelin. To develop a contrast agent for MR imaging, we explored the possibility of introducing a linker in the 3-position so that CMC could be conjugated to a gadolinium complex based on a DOTA derived monoamide macrocyclic ligand (DOTA = 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid).…”

Section: Introductionmentioning

confidence: 81%

Myelin Imaging Compound (MIC) Enhanced Magnetic Resonance Imaging of Myelination

et al. 2011

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The vertebrate nervous system is characterized by myelination, a fundamental biological process that protects the axons and facilitates electric pulse transduction. Damage to myelin is considered a major effect of autoimmune diseases such as multiple sclerosis (MS). Currently, therapeutic interventions are focused on protecting myelin integrity and promoting myelin repair. These efforts need to be accompanied by an effective imaging tool that correlates the disease progression with the extent of myelination. To date, magnetic resonance imaging (MRI) is the primary imaging technique to detect brain lesions in MS. However, conventional MRI cannot differentiate demyelinated lesions from other inflammatory lesions, and therefore cannot predict disease progression in MS. To address this problem, we have prepared a Gd-based contrast agent, termed MIC (Myelin Imaging Compound), which binds to myelin with high specificity. In this work, we demonstrate that MIC exhibits a high kinetic stability towards transmetallation with promising relaxometric properties. MIC was used for in vivo imaging of myelination following intracerebroventricular infusion in the rat brain. MIC was found to distribute preferentially in highly myelinated regions and was able to detect regions of focally induced demyelination.

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Section: Introductionmentioning

confidence: 81%

Myelin Imaging Compound (MIC) Enhanced Magnetic Resonance Imaging of Myelination

et al. 2011

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“…2A). Because of the quantitative limits of immunofluorescence techniques and the possibility that melanin autofluorescence might interfere with the analyses, we examined the same tissue biopsies using an infraredbased method, which allows for the quantitative comparison of normal and diseased skin (20). The results show that stage II melanoma lesions (21) were associated with significantly higher AC immunoreactivity, compared with normal skin or node-positive (stage III-IV, N1 or N2, M0, or M1) melanoma (Fig.…”

Section: High Ac Expression In Human Melanoma Cell Lines Andmentioning

confidence: 99%

Acid Ceramidase in Melanoma

Realini

Palese

Pizzirani

et al. 2016

Journal of Biological Chemistry

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Acid ceramidase (AC) is a lysosomal cysteine amidase that controls sphingolipid signaling by lowering the levels of ceramides and concomitantly increasing those of sphingosine and its bioactive metabolite, sphingosine 1-phosphate. In the present study, we evaluated the role of AC-regulated sphingolipid signaling in melanoma. We found that AC expression is markedly elevated in normal human melanocytes and proliferative melanoma cell lines, compared with other skin cells (keratinocytes and fibroblasts) and non-melanoma cancer cells. High AC expression was also observed in biopsies from human subjects with Stage II melanoma. Immunofluorescence studies revealed that the subcellular localization of AC differs between melanocytes (where it is found in both cytosol and nucleus) and melanoma cells (where it is primarily localized to cytosol). In addition to having high AC levels, melanoma cells generate lower amounts of ceramides than normal melanocytes do. This downregulation in ceramide production appears to result from suppression of the de novo biosynthesis pathway. To test whether AC might contribute to melanoma cell proliferation, we blocked AC activity using a new potent (IC 50 ‫؍‬ 12 nM) and stable inhibitor. AC inhibition increased cellular ceramide levels, decreased sphingosine 1-phosphate levels, and acted synergistically with several, albeit not all, antitumoral agents. The results suggest that AC-controlled sphingolipid metabolism may play an important role in the control of melanoma proliferation.Ceramides are a class of bioactive lipids that regulate senescence, apoptosis, and autophagy (1). They comprise more than 200 chemically and functionally distinct molecules and are produced through either de novo biosynthesis or cleavage of preformed sphingolipid precursors in membranes (2-4). They are degraded by the action of five distinct ceramidases, which differ in sequence, structure, subcellular localization, and preferred substrates (5). Among them, acid ceramidase (AC) 2 (also known as N-acetylsphingosine amidohydrolase, ASAH1) is especially relevant due to its possible roles in cancer progression and chemoresistance (6). AC is a lysosomal cysteine amidase that catalyzes the hydrolysis of ceramide into sphingosine and fatty acid with a preference for unsaturated ceramides with 6 -16-carbon acyl chains (5). Its activation is associated with decreased cellular levels of these medium-chain ceramides, which promote senescence and apoptosis, and increased levels of sphingosine 1-phosphate (S1P), which stimulates cell proliferation and cancer cell migration (7). A bioinformatic survey of the National Cancer Institute (NCI) gene expression database conducted in 2003 identified AC as a potential candidate for the development of new biomarkers for the prognosis of melanoma (8). Supporting this possibility, subsequent studies showed that serum of melanoma patients contains AC autoantibodies (9). Moreover, experiments with melanoma cell lines in cultures have demonstrated that dacarbazine, a standard of care for the...

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“…Schmahl et al (1999) described staining of myelin in tissue sections using a cyanine dye 5,5'-diphenyl-9-ethyl-oxacarbocyanine (DEOC), and Xiang et al (2005) described the synthesis and characterization of two squarylium-based near infra-red myelin (NIM) dyes with selectivity for myelin. For in vivo imaging, Wang and colleagues described a number of fluorescent dyes including (E,E)-1,4-bis(4'-aminostyryl)-2-dimethoxy-benzene (BDB), 3-(4-aminophenyl)-2H-chromen-2-one (termed Case Myelin Compound), and 3,3’-diethylthiatricarbocyanine iodide (DBT), which penetrate the blood-brain barrier and bind selectively to myelin in the central and peripheral nervous systems (Wang et al, 2010; Wang et al, 2011; Wu et al, 2006). …”

Section: Introductionmentioning

confidence: 99%

FluoroMyelin™ Red is a bright, photostable and non-toxic fluorescent stain for live imaging of myelin

Monsma

Brown

2012

Journal of Neuroscience Methods

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FluoroMyelin™ Red is a commercially available water-soluble fluorescent dye that has selectivity for myelin. This dye is marketed for the visualization of myelin in brain cryosections, though it is also used widely to stain myelin in chemically fixed tissue. Here we have investigated the suitability of FluoroMyelin™ Red as a vital stain for live imaging of myelin in myelinating co-cultures of Schwann cells and dorsal root ganglion neurons. We show that addition of FluoroMyelin™ Red to the culture medium results in selective staining of myelin sheaths, with an optimal staining time of 2 hours, and has no apparent adverse effect on the neurons, their axons, or the myelinating cells at the light microscopic level. The fluorescence is bright and photostable, permitting long-term time-lapse imaging. After rinsing the cultures with medium lacking FluoroMyelin™ Red, the dye diffuses out of the myelin with a half life of about 130 minutes resulting in negligible fluorescence remaining after 18–24 hours. In addition, the large Stokes shift exhibited by FluoroMyelin™ Red makes it possible to readily distinguish it from popular and widely used green and red fluorescent probes such as GFP and mCherry. Thus FluoroMyelin™ Red is a useful reagent for live fluorescence imaging studies on myelinated axons.

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In Situ Fluorescence Imaging of Myelination

Cited by 54 publications

References 20 publications

Myelin Imaging Compound (MIC) Enhanced Magnetic Resonance Imaging of Myelination

Myelin Imaging Compound (MIC) Enhanced Magnetic Resonance Imaging of Myelination

Acid Ceramidase in Melanoma

FluoroMyelin™ Red is a bright, photostable and non-toxic fluorescent stain for live imaging of myelin

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