Guinea-pig primary cell cultures provide a model to study expression and amyloidogenic processing of endogenous amyloid precursor protein

Beck, Mike; Brückner, Martina K.; Holzer, Max; Kaap, S.; Pannicke, Thomas; Arendt, Thomas; Bigl, Volker

doi:10.1016/s0306-4522(99)00390-5

Cited by 19 publications

(19 citation statements)

References 91 publications

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“…Our data are also consistent with work that suggests that large amounts of the APP ectodomain shed into the extracellular space may serve a nonspecific neuroprotective role (25). Our work is consistent with that of others (7,9) who have shown large amounts of A␤ accumulate in the supernatant of cultured neurons. The work by Seubert et al (7) is particularly relevant as they measured 72-h accumulation of A␤ in the supernatant of cultured human neurons at 4 ng/ml, a number not inconsistent with our results (by extrapolation).…”

Section: Discussionsupporting

confidence: 82%

“…Both in vitro and in vivo evidence suggests that A␤ is secreted from cells under normal physiological conditions (3,4,(7)(8)(9) but the absolute amount, an important consideration given its proposed roles and pharmacologic interest, has not been precisely calculated. In addition, the relative amount of intracellular versus extracellular A␤ production and its ultimate disposition in neurons is unclear (10).…”

Section: Alzheimer Disease (Ad)mentioning

confidence: 99%

See 1 more Smart Citation

Large Quantities of Aβ Peptide Are Constitutively Released during Amyloid Precursor Protein Metabolism in Vivo and in Vitro

Moghekar¹,

Rao²,

Li³

et al. 2011

Journal of Biological Chemistry

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The metabolism of the amyloid precursor protein (APP) has been extensively investigated because its processing generates the amyloid-␤-peptide (A␤), which is a likely cause of Alzheimer disease. Much prior research has focused on APP processing using transgenic constructs and heterologous cell lines. Work to date in native neuronal cultures suggests that A␤ is produced in very large amounts. We sought to investigate APP metabolism and A␤ production simultaneously under more physiological conditions in vivo and in vitro using cultured rat cortical neurons and live pigs. We found in cultured neurons that both APP and A␤ are secreted rapidly and at extremely high rates into the extracellular space (2-4 molecules/neuron/s for A␤). Little APP is degraded outside of the pathway that leads to extracellular release. Two metabolic pools of APP are identified, one that is metabolized extremely rapidly (t1 ⁄ 2 ‫؍‬ 2.2 h), and another, surface pool, composed of both synaptic and extrasynaptic elements, that turns over very slowly. A␤ release and accumulation in the extracellular medium can be accounted for stoichiometrically by the extracellular release of ␤-cleaved forms of the APP ectodomain. Two ␣-cleavages of APP occur for every ␤-cleavage. Consistent with the results seen in cultured neurons, an extremely high rate of A␤ production and secretion from the brain was seen in juvenile pigs. In summary, our experiments show an enormous and rapid production and extracellular release of A␤ and the soluble APP ectodomain. A small, slowly metabolized, surface pool of full-length APP is also identified. Alzheimer disease (AD)2 is a progressive, neurodegenerative process characterized pathologically by accumulation of the ␤-amyloid peptide (A␤) in the form of extracellular plaques (1). On the basis of genetic, cellular, and animal studies the amyloid hypothesis postulates that increased deposition of A␤ in the brain is the primary influence in the pathogenesis of AD (2). A␤ is part of the amyloid precursor protein (APP) that is expressed ubiquitously by neuronal and non-neuronal cells (3-5). APP is a type 1 transmembrane glycoprotein that undergoes sequential site-specific proteolytic cleavages by either ␣-or ␤-secretase followed by ␥-secretase, which cleaves APP in the transmembrane domain to yield several secreted derivatives. Cleavage of APP by the ␤-secretase BACE1 releases a large fragment called sAPP␤ leaving behind a fragment that is acted upon by ␥-secretase at different sites to release several short peptides of which A␤40 and A␤42 are the major components (6). Alternatively, cleavage of APP by ␣-secretase occurs within the A␤ domain, precluding the formation of A␤ and resulting in the secretion of sAPP␣, a short peptide called p3, and a C-terminal domain, none of which are amyloidogenic.Both in vitro and in vivo evidence suggests that A␤ is secreted from cells under normal physiological conditions (3, 4, 7-9) but the absolute amount, an important consideration given its proposed roles and pharmacologic interest, has not...

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Section: Discussionsupporting

confidence: 82%

Section: Alzheimer Disease (Ad)mentioning

confidence: 99%

Large Quantities of Aβ Peptide Are Constitutively Released during Amyloid Precursor Protein Metabolism in Vivo and in Vitro

Moghekar¹,

Rao²,

Li³

et al. 2011

Journal of Biological Chemistry

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“…In Guinea pigs ( Cavia porcellus ), with a human identical Aβ sequence (see Fig. 1) and a lifespan similar to degus (average 5–7 [45]), dense amyloid deposits do not occur [45], despite similar APP processing [46, 47] and high β–secretase activity [47]. …”

Section: Discussionmentioning

confidence: 99%

Revisiting rodent models: Octodon degus as Alzheimer’s disease model?

Steffen

Krohn

Paarmann

et al. 2016

acta neuropathol commun

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Alzheimer’s disease primarily occurs as sporadic disease and is accompanied with vast socio-economic problems. The mandatory basic research relies on robust and reliable disease models to overcome increasing incidence and emerging social challenges. Rodent models are most efficient, versatile, and predominantly used in research. However, only highly artificial and mostly genetically modified models are available. As these ‘engineered’ models reproduce only isolated features, researchers demand more suitable models of sporadic neurodegenerative diseases. One very promising animal model was the South American rodent Octodon degus, which was repeatedly described as natural ‘sporadic Alzheimer’s disease model’ with ‘Alzheimer’s disease-like neuropathology’. To unveil advantages over the ‘artificial’ mouse models, we re-evaluated the age-dependent, neurohistological changes in young and aged Octodon degus (1 to 5-years-old) bred in a wild-type colony in Germany. In our hands, extensive neuropathological analyses of young and aged animals revealed normal age-related cortical changes without obvious signs for extensive degeneration as seen in patients with dementia. Neither significant neuronal loss nor enhanced microglial activation were observed in aged animals. Silver impregnation methods, conventional, and immunohistological stains as well as biochemical fractionations revealed neither amyloid accumulation nor tangle formation. Phosphoepitope-specific antibodies against tau species displayed similar intraneuronal reactivity in both, young and aged Octodon degus.In contrast to previous results, our study suggests that Octodon degus born and bred in captivity do not inevitably develop cortical amyloidosis, tangle formation or neuronal loss as seen in Alzheimer’s disease patients or transgenic disease models.

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“…Other groups who applied urea‐based Aβ‐SDS–PAGE/immunoblot for the analysis of secreted Aβ peptides may have missed Aβ1–37/38/39 due to misinterpretation as cross‐reactive proteins (Cescato et al . 2000) or aggregated Aβ peptides (Beck et al . 2000).…”

Section: Discussionmentioning

confidence: 99%

Highly conserved and disease‐specific patterns of carboxyterminally truncated Aβ peptides 1–37/38/39 in addition to 1–40/42 in Alzheimer's disease and in patients with chronic neuroinflammation

Wiltfang¹,

Esselmann²,

Bibl³

et al. 2002

Journal of Neurochemistry

254

295

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Human lumbar CSF patterns of Ab peptides were analysed by urea-based b-amyloid sodium dodecyl sulphate polyacrylamide gel electrophoresis with western immunoblot (Ab-SDS-PAGE/immunoblot). A highly conserved pattern of carboxyterminally truncated Ab1-37/38/39 was found in addition to Ab1-40 and Ab1-42. Remarkably, Ab1-38 was present at a higher concentration than Ab1-42, being the second prominent Ab peptide species in CSF. Patients with Alzheimer's disease (AD, n ¼ 12) and patients with chronic inflammatory CNS disease (CID, n ¼ 10) were differentiated by unique CSF Ab peptide patterns from patients with other neuropsychiatric diseases (OND, n ¼ 37). This became evident only when we investigated the amount of Ab peptides relative to their total Ab peptide concentration (Ab1-x%, fractional Ab peptide pattern), which may reflect diseasespecific c-secretase activities. Remarkably, patients with AD and CID shared elevated Ab1-38% values, whereas otherwise the patterns were distinct, allowing separation of AD from CID or OND patients without overlap. The presence of one or two ApoE e4 alleles resulted in an overall reduction of CSF Ab peptides, which was pronounced for Ab1-42. The severity of dementia was significantly correlated to the fractional Ab peptide pattern but not to the absolute Ab peptide concentrations. Keywords: Alzheimer's disease (AD), b-amyloid protein precursor/metabolism, biological markers, cerebrospinal fluid, 2D-PAGE, western immunoblot.

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Guinea-pig primary cell cultures provide a model to study expression and amyloidogenic processing of endogenous amyloid precursor protein

Cited by 19 publications

References 91 publications

Large Quantities of Aβ Peptide Are Constitutively Released during Amyloid Precursor Protein Metabolism in Vivo and in Vitro

Large Quantities of Aβ Peptide Are Constitutively Released during Amyloid Precursor Protein Metabolism in Vivo and in Vitro

Revisiting rodent models: Octodon degus as Alzheimer’s disease model?

Highly conserved and disease‐specific patterns of carboxyterminally truncated Aβ peptides 1–37/38/39 in addition to 1–40/42 in Alzheimer's disease and in patients with chronic neuroinflammation

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