Apolipoproteins in rat cerebrospinal fluid: A comparison with plasma lipoprotein metabolism and effect of aging

Chiba, Hitoshi; Mitamura, Teruaki; Fujisawa, Shinichi; Ogata, Akihiko; Aimoto, Yasuharu; Tashiro, Kunio; Kobayashi, Kunihiko

doi:10.1016/0304-3940(91)90571-a

Cited by 22 publications

(7 citation statements)

References 17 publications

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“…Whether use of astrocyte cultures derived from adult tissue would result in cells with similar or different properties, with regard to secretion of A-LPs, than those reported here is unclear but can be addressed in future studies. Although information is limited, human and rat CSF appear comparable in terms of the presence of apoE and apoAl on HDL-sized particles (Chiba et a!., 1991). Human astrocytoma cells secrete apoE-containing HDL-sized particles similar to those described here (Krul and Tang, 1992).…”

Section: Figsupporting

confidence: 57%

Nascent Astrocyte Particles Differ from Lipoproteins in CSF

LaDu

Gilligan

Lukens

et al. 1998

Journal of Neurochemistry

259

253

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Abstract:Little is known about lipid transport and metabolism in the brain. As a further step toward understanding the origin and function of CNS lipoproteins, we have characterized by size and density fractionation lipoprotein particles from human CSF and primary cultures of rat astrocytes. The fractions were analyzed for esterified and free cholesterol, triglyceride, phospholipid, albumin, and apolipoproteins (apo) E, Al, All, and J. As determined by lipid and apolipoprotein profiles, gel electrophoresis, and electron microscopy, nascent astrocyte particles contain little core lipid, are primarily discoidal in shape, and contain apoE and apoJ. In contrast, CSF lipoproteins are the size and density of plasma high-density lipoprotein, contain the core lipid, esterified cholesterol, and are spherical. CSF lipoproteins were heterogeneous in apolipoprotein content with apoE, the most abundant apolipoprotein, localized to the largest particles, apoAl and apoAll localized to progressively smaller particles, and apoJ distributed relatively evenly across particle size. There was substantial loss of protein from both CSF and astrocyte particles after density centrifugation compared with gel-filtration chromatography. The differences between lipoproteins secreted by astrocytes and present in CSF suggest that in addition to delivery of their constituents to cells, lipoprotein particles secreted within the brain by astrocytes may have the potential to participate in cholesterol clearance, developing a core of esterified cholesterol before reaching the CSF. Study of the functional properties of both astrocyte-secreted and CSF lipoproteins isolated by techniques that preserve native particle structure may also provide insight into the function of apoE in the pathophysiology of specific neurological diseases such as Alzheimer's disease. Key Words: Apolipoprotein E-Apolipoprotein J -Apolipoprotein Al -Alzheimer's disease-Cholesterol. J. Neurochem. 70, 2070Neurochem. 70, -2081Neurochem. 70, (1998.The intercellular transport of lipids through the aqueous circulatory system requires the packaging of these hydrophobic molecules into water-soluble carriers known as lipoproteins (high-density lipoprotein HDL; low-density lipoprotein LDL; and very-low-density lipoprotein, VLDL). Lipoproteins are macromolecular complexes composed of a phospholipid (PL) and free cholesterol (FC) shell surrounding a triglyceride (TG) and cholesteryl ester (CE) core (see Fig. 6A). Lipoproteins also contain apolipoproteins (apo), proteins that stabilize the surface of lipoproteins as they have both hydrophobic and hydrophilic domains. Apolipoproteins can also serve as cofactors for enzymatic reactions (Fielding et al., 1972) and ligands for cell surface receptors (Brown and Goldstein, 1986). In addition, alterations in apolipoproteins are associated with pathological conditions (Mahley, 1988). Whereas the regulation of lipoprotein metabolism and its effects on systemic lipid regulation have been studied extensively, much less is known about lipid tran...

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Section: Figsupporting

confidence: 57%

Nascent Astrocyte Particles Differ from Lipoproteins in CSF

LaDu

Gilligan

Lukens

et al. 1998

Journal of Neurochemistry

259

253

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“…The brain cells are segregated from lipoproteins in the systemic circulation by the blood-brain barrier, so that cholesterol homeostasis in the brain is dependent on its specific extracellular lipid transport system by apolipoproteins and lipoproteins (1)(2)(3)(4)(5). Helical apolipoproteins such as apolipoprotein E (apoE), apoA-I, apoD, apoA-IV, and apoJ have been identified in the cerebrospinal fluid as components of HDL, but the main apolipoproteins are apoE and apoA-I (6-10).…”

mentioning

confidence: 99%

Astrocytes produce and secrete FGF-1, which promotes the production of apoE-HDL in a manner of autocrine action

Ito

Nagayasu

et al. 2005

Journal of Lipid Research

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“…The main apolipoproteins in mammalian cerebrospinal fluid (CSF) are apolipoprotein A-I (apoA-I) and apoE (1)(2)(3), which are present as HDL and play major roles in intercellular cholesterol transport in the brain (4), being segregated by the blood-brain barrier from the lipoprotein system in the systemic circulation. Astrocytes and partly microglia cells generate cholesterol-rich HDL by endogenous apoE along with cellular cholesterol and phospholipid (5)(6)(7)(8)(9).…”

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confidence: 99%