Imaging of sialidase activity in rat brain sections by a highly sensitive fluorescent histochemical method

Minami, Akira; Shimizu, Hirotaka; Meguro, Yuko; Shibata, Naoki; Kanazawa, Hiroaki; Ikeda, Kiyoshi; Suzuki, Takashi

doi:10.1016/j.neuroimage.2011.06.017

Cited by 19 publications

(19 citation statements)

References 38 publications

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“…We stained an acute hippocampal slice with ZnAF-2DA and X-Neu5Ac/FRV LB simultaneously. As a result, mossy fiber terminals determined with ZnAF-2DA showed relatively intense sialidase activities in the hippocampus (Fig.4) (23). Since mossy fibers are unmyelinated axons, sialidase activity at mossy fiber terminals would be detected directly from neurons but not from myelin.…”

Section: D-1 Neural Circuit and Distribution Of Sialidase Activity Imentioning

confidence: 92%

“…Acute colonal brain slices (400 μm in thickness, anterior-posterior from the bregma, AP: -3.0 mm) were incubated at pH 7.3 (27°C) for 1 hour with 1 mM X-Neu5Ac and 0.1 mg/ml FRV LB. The white matter region including the corpus callosum, dorsal hippocampus commissure, alveus, fimbria, internal capsule and cerebral peduncle clearly showed high fluorescence intensity ( Fig.2A) (23). White matter also showed intense sialidase activity in other brain slice sections (Fig.2B-E).…”

Section: B Distribution Of Sialidase Activity In the Brainmentioning

confidence: 92%

“…Sialidase activity detected with X-Neu5Ac and FRV LB were attenuated with a sialidase inhibitor, 2,3-dehydro-2-deoxy-N-acetylneuraminic acid (DANA) (Fig.2F) (23). Additionally, the fluorescence intensities caused by X-Neu5Ac and FRV LB were correlated with the sialidase activity measured with 4-methylumbelliferyl-α-D-Nacetylneuraminic acid (4MU-Neu5Ac), a classical substrate for quantitative measurement of sialidase activity, in each brain region.…”

Section: B Distribution Of Sialidase Activity In the Brainmentioning

confidence: 99%

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Distribution of Sialidase Activity and the Role of Sialidase in the Brain

Minami¹,

Suzuki²

2012

TIGG

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Sialic acid is an acidic monosaccaride and plays crucial roles in various membrane functions in mammalian central nervous systems. Sialidase removes sialic acid from sialoglycoconjugates and also plays crucial roles in many neural functions, including differentiation and maturation of neurons and learning and memory. Recently, we visualized extracellular sialidase activity on the membrane surface in the rat brain by using a highly sensitive fluorescent histochemical method. Myelin-abundant regions showed intense fluorescence in the rat brain. Although the hippocampus showed weak fluorescence in the brain, mossy fiber terminals in the hippocampus showed relatively intense fluorescence. In this review, we describe the distribution of sialidase activity in the brain and discuss the role of sialidase in myelin and the hippocampus. A. Introduction S i a l i d a s e r e m o v e s s i a l i c a c i d r e s i d u e s f r o m sialoglycoconjugates, such as glycoproteins and glycolipids.Four types of mammalian sialidase (Neu1, Neu2, Neu3 and Neu4) have been identified in mammalian tissues by their localization and enzymatic properties. These four types of sialidase were reported to be expressed in mammalian brains (1). Since sialidase extracellularly applied to the rat hippocampus influences many neural functions including memory, synaptic plasticity, axon outgrowth and neural differentiation, activities of endogenous sialidases on the extracellular membrane surface would also affect neural functions (2-5). Neu1, Neu2 and Neu3 show enzyme activity on the extracellular membrane surface. Neu1 specifically acts on low-molecular-weight substrates, including 4MU-Neu5Ac, oligosaccharides and glycopeptides (6,7). Neu1 is mainly located at lysosomes. Neu1 is relocalized from the lysosome to the cell surface with activation of T cells and differentiation of monocytes (8,9). Neu2 hydrolyzes gangliosides and glycoproteins at neutral pH. Neu2 is located mainly in the cytoplasm but also in plasma membranes in the mouse

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Section: D-1 Neural Circuit and Distribution Of Sialidase Activity Imentioning

confidence: 92%

Section: B Distribution Of Sialidase Activity In the Brainmentioning

confidence: 92%

Section: B Distribution Of Sialidase Activity In the Brainmentioning

confidence: 99%

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Distribution of Sialidase Activity and the Role of Sialidase in the Brain

Minami¹,

Suzuki²

2012

TIGG

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“…When BTP3-Neu5Ac, which is water-soluble and shows little fluorescence, is cleaved by sialidase, the water-insoluble BTP3 having intense fluorescence under UV light is released and stains tissue clearly (Fig 1A) [13]. We also developed a fluorescent histochemical imaging method for sialidase activity by using the combination of 5-bromo-4-chloroindol-3-yl-α-D-N-acetylneuraminic acid (X-Neu5Ac) and Fast Red Violet LB (FRV LB) [14]. To visualize the distribution of extracellular sialidase activity, rat brain slices were stained with BTP3-Neu5Ac or X-Neu5Ac and FRV LB at neutral pH.…”

Section: Introductionmentioning

confidence: 99%

“…To visualize the distribution of extracellular sialidase activity, rat brain slices were stained with BTP3-Neu5Ac or X-Neu5Ac and FRV LB at neutral pH. The hippocampus showed weak but positive sialidase activity, although the white matter region showed the most intense sialidase activity in the brain [13, 14]. …”

Section: Introductionmentioning

confidence: 99%

Role of Sialidase in Long-Term Potentiation at Mossy Fiber-CA3 Synapses and Hippocampus-Dependent Spatial Memory

et al. 2016

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Sialic acid bound to glycans in glycolipids and glycoproteins is essential for synaptic plasticity and memory. Sialidase (EC 3.2.1.18), which has 4 isozymes including Neu1, Neu2, Neu3 and Neu4, regulates the sialylation level of glycans by removing sialic acid from sialylglycoconjugate. In the present study, we investigated the distribution of sialidase activity in rat hippocampus and the role of sialidase in hippocampal memory processing. We previously developed a highly sensitive histochemical imaging probe for sialidase activity, BTP3-Neu5Ac. BTP3-Neu5Ac was cleaved efficiently by rat Neu2 and Neu4 at pH 7.3 and by Neu1 and Neu3 at pH 4.6. When a rat hippocampal acute slice was stained with BTP3-Neu5Ac at pH 7.3, mossy fiber terminal fields showed relatively intense sialidase activity. Thus, the role of sialidase in the synaptic plasticity was investigated at mossy fiber terminal fields. The long-term potentiation (LTP) at mossy fiber-CA3 pyramidal cell synapses was impaired by 2,3-dehydro-2-deoxy-N-acetylneuraminic acid (DANA), a sialidase inhibitor. DANA also failed to decrease paired-pulse facilitation after LTP induction. We also investigated the role of sialidase in hippocampus-dependent spatial memory by using the Morris water maze. The escape latency time to reach the platform was prolonged by DANA injection into the hippocampal CA3 region or by knockdown of Neu4 without affecting motility. The results show that the regulation of sialyl signaling by Neu4 is involved in hippocampal memory processing.

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