Saturday, October 31, 2009

Involvement of Dab1 in APP processing and ß-amyloid deposition in sporadic Creutzfeldt–Jakob patients

Copyright © 2009 Published by Elsevier Inc.

Involvement of Dab1 in APP processing and ß-amyloid deposition in sporadic Creutzfeldt–Jakob patients

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R. Gavína, c, I. Ferrerb, c, , and J.A. del Ríoa, c, ,

aMolecular and Cellular Neurobiotechnology, Institute of Bioengineering of Catalonia and Department of Cell Biology, University of Barcelona, Baldiri Reixac 15-21, 08028 Barcelona, Spain

bInstitute of Neuropathology (INP), IDIBELL-Hospital Universitari de Bellvitge, Faculty of Medicine, University of Barcelona, 08907 Hospitalet de LLobregat, Barcelona, Spain

cCentro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Barcelona, Spain

Received 27 March 2009; revised 5 October 2009; accepted 10 October 2009. Available online 21 October 2009.

Abstract Alzheimer's disease and prion pathologies (e.g., Creutzfeldt–Jakob disease (CJD)) display profound neural lesions associated with aberrant protein processing and extracellular amyloid deposits. Dab1 has been implicated in the regulation of amyloid precursor protein (APP), but a direct link between human prion diseases and Dab1/APP interactions has not been published. Here we examined this putative relationship in 17 cases of sporadic CJD (sCJD) post-mortem. Biochemical analyses of brain tissue revealed two groups, which also correlated with PrPsc types 1 and 2. One group with PrPsc type 1 showed increased Dab1 phosphorylation and lower ßCTF production with an absence of Aß deposition. The second sCJD group, which carried PrPsc type 2, showed lower levels of Dab1 phosphorylation and ßCTF production, and Aß deposition. Thus, the present observations suggest a correlation between Dab1 phosphorylation, Aß deposition and PrPsc type in sCJD.

Keywords: Prionopathies; Amyloid plaques; Alzheimer's disease; Dab1

Article Outline Introduction Patients and methods Cases PrP typing Codon 129 genotyping Immunoprecipitation and Western immunoblotting Densitometry and statistical processing Results Analysis of Dab1 phosphorylation revealed two groups of sCJD cases ßCTF production and Aß deposition in sCJD Correlation between codon 129 polymorphism with PrPsc type and Aß deposits in sCJD groups Discussion Acknowledgements References

Fig. 1. Patterns of PrPsc type 1 and type 2 (PK: proteinase K pre-treatment). Three examples of PrPsc processing are illustrated. Every sample is run in parallel with a negative control (lane 1), a typical case of PrPsc type 1 (lane 2), a typical case type 2 (lane 3) and the case problem (lane 4).

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Fig. 2. Example of Western blot determination of pDab1 (A and B) and total Dab1 protein levels (C and D) in sCJD cases. sCJD cases were categorized as described above. Protein samples from different groups of sCJD (first and second groups) are shown. (B) The densitometric results are shown. Each data item corresponding to a sCJD case is displayed in the histograms. In addition, the mean and SEM in each group is also shown. A significant increase in the pDab1/Dab1 ratio is observed in the first group of sCJD cases compared to the second sCJD group and controls. (C and D) Parallel determination of total Dab1 levels in the same sCJD protein samples. The increased phosphorylation of Dab1 in the first sCJD cases correlates with decreased levels of total protein. Each dot corresponds to a single case. Asterisks indicate significant differences between sCJD groups and controls in (B) and (D). p < 0.05; p < 0.01 (ANOVA test). View Within Article --------------------------------------------------------------------------------

Fig. 3. Example of Western blotting determination of ßCTF (A and B) in sCJD cases compared to controls. sCJD cases were categorized as described above. Decreased levels of ßCTF can be seen in the first sCJD group compared to controls. (B) Histograms showing the densitometric study as in Fig. 2. Each dot corresponds to a single case. Asterisks indicate significant differences between sCJD groups and controls. p < 0.05 (ANOVA test). View Within Article --------------------------------------------------------------------------------

Fig. 4. Double-Y graphs illustrating the densitometric results of pDab1/Dab1 ratio (left Y axis) and CTFß levels (blue right Y axis) for each case (X axis). Each dot/square corresponds to a single case. Values of pDab1/Dab1 (black squares) and CTFß (blue circles) have been linked with a line and the area (grey for pDab1/Dab1 and violet for CTFß) has been completed for each patient group. Notice the clear differences in the distribution of the grey and violet areas between the 1st and the 2nd group of sCJD cases and controls. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.) View Within Article --------------------------------------------------------------------------------

Fig. 5. Low power photomicrographs illustrating examples of amyloid plaques in some of the sCJD cases used in the present study after Aß immunocytochemistry. (A) No plaques (score 0). (B) A few diffuse plaques (score +). (C) Many diffuse plaques, some neuritic plaques (score ++). See Results for details. Scale bar (A) = 500 µm pertains to (B) and (C). View Within Article --------------------------------------------------------------------------------

Table 1. Main clinical characteristics of sCJD and control cases in the present study. F: female; M: male; M: methionine; V: valine; PrP type: PrPsc type 1: lower band of glycosylated PrPsc of 21 kDa; type 2: lower band of glycosylated PrPsc of 10 kDa. Aß plaques: 0, no plaques; +, a few diffuse plaques; ++, many diffuse plaques and some neuritic plaques. View Within Article Corresponding authors. J.A. del Río is to be contacted at MCN lab Institute of Bioengineering of Catalonia Baldiri and Reixac 15-20, 08028 Barcelona, Spain. Fax: +34 934020183. I. Ferrer, Institut de Neuropatologia Servei Anatomia Patològica IDIBELL-Hospital Universitari de Bellvitge Facultat de Medicina Universitat de Barcelona Feixa LLarga sn, 08907 Hospitalet de LLobregat, Barcelona, Spain. Fax: +34 934035810.


----- Original Message -----

From: "Terry S. Singeltary Sr."
Sent: Monday, October 12, 2009 9:47 AM
Subject: [BSE-L] SEAC Science and Technology Committee's investigation of research funding priorities on behalf of the Advisory Committee on Dangerous Pathogens Transmissible Spongiform Encephalopathy

-------------------- BSE-L@LISTS.AEGEE.ORG --------------------


. More specific examples of unanswered questions with health implications are:

. Will the eventual elimination of classical scrapie in the EU leave an ecological niche for other TSEs such as BSE or atypical scrapie?

. Is CWD transmissible to humans?

. Can a reliable ante mortem diagnostic blood test for vCJD be developed?

. What is the true prevalence of v CJD infection (as opposed to overt disease) in the UK?



. Are some commoner types of neurodegenerative disease (including Alzheimer's disease and Parkinson's disease) also transmissible? Some recent scientific research has suggested this possibility



. Could cases of protease sensitive prionopathy (PSP) be missed by conventional tests which, in all other TSEs, rely on the resistance of the prion protein in the nervous system that accompanies disease to digestion by protease enzymes?

. Can we develop reliable methods for removing and detecting protein on re-usable surgical instruments?



Monday, October 12, 2009

SEAC Science and Technology Committee's investigation of research funding priorities on behalf of the Advisory Committee on Dangerous Pathogens TSE 8 October 2009

----- Original Message -----
From: "Terry S. Singeltary Sr."
Sent: Monday, June 29, 2009 2:08 PM
Subject: [BSE-L] Beyond the prion principle

-------------------- BSE-L@LISTS.AEGEE.ORG --------------------

News and Views Nature 459, 924-925 (18 June 2009) doi:10.1038/459924a; Published online 17 June 2009


Beyond the prion principle

Adriano Aguzzi

It seems that many misfolded proteins can act like prions - spreading disease by imparting their misshapen structure to normal cellular counterparts. But how common are bona fide prions really?

The protein-only hypothesis of prion propagation is steadily gaining ground. First envisaged by John Stanley Griffith1 and later formalized by Stanley Prusiner2, this theory proposes the existence of an infectious agent composed solely of protein. Three reports, two in Nature Cell Biology3,4 and one in The Journal of Cell Biology5, now contend that, far from being confined to the rare prion diseases, prion-like transmission of altered proteins may occur in several human diseases of the brain and other organs.

Prions are now accepted as causing the transmissible spongiform encephalopathies, which include scrapie in sheep, bovine spongiform encephalopathy (BSE, or mad cow disease) and its human variant Creutzfeldt-Jakob disease. The infectious prion particle is made up of PrPSc, a misfolded and aggregated version of a normal protein known as PrPC. Like the growth of crystals, PrPSc propagates by recruiting monomeric PrPC into its aggregates - a process that has been replicated in vitro6 and in transgenic mice7. The breakage of PrPSc aggregates represents the actual replicative event, as it multiplies the number of active seeds8.

Apart from prion diseases, the misfolding and aggregation of proteins into various harmful forms, which are collectively known as amyloid, causes a range of diseases of the nervous system and other organs. The clinical characteristics of amyloidoses, however, gave little reason to suspect a relationship to prion diseases. Hints of prion-like behaviour in amyloid have emerged from studies of Alzheimer's disease and Parkinson's disease. Alzheimer's disease had been suspected to be transmissible for some time: an early report9 of disease transmission to hamsters through white blood cells from people with Alzheimer's disease caused great consternation, but was never reproduced. Much more tantalizing evidence came from the discovery10,11 that aggregates of the amyloid-â (Aâ) peptide found in the brain of people with Alzheimer's disease could be transmitted to the brain of mice engineered to produce large amounts of the Aâ precursor protein APP. Another study12 has shown that healthy tissue grafted into the brain of people with Parkinson's disease acquires intracellular Lewy bodies - aggregates of the Parkinson's disease-associated protein á-synuclein. This suggests prion-like transmission of diseased protein from the recipient's brain to the grafted cells.

These findings10-12 raise a provocative question. If protein aggregation depends on the introduction of 'seeds' and on the availability of the monomeric precursor, and if, as has been suggested13, amyloid represents the primordial state of all proteins, wouldn't all proteins - under appropriate conditions - behave like prions in the presence of sufficient precursor? Acceptance of this concept is gaining momentum. For one thing, an increasing wealth of traits is being found in yeast, fungi and bacteria that can best be explained as prion-like phenomena (see table). And now, Ren and colleagues3 provide evidence for prion-like spread of polyglutamine (polyQ)- containing protein aggregates, which are similar to the aggregates found in Huntington's disease. They show that polyQ aggregates can be taken up from the outside by mammalian cells. Once in the cytosol, the polyQ aggregates can grow by recruiting endogenous polyQ. Clavaguera et al.4 report similar findings in a mouse model of tauopathy, a neurodegenerative disease caused by intraneuronal aggregation of the microtubule-associated tau protein. Injection of mutant human tau into the brain of mice overexpressing normal human tau transmitted tauopathy, with intracellular aggregation of previously normal tau and spread of aggregates to neighbouring regions of the brain. Notably, full-blown tauopathy was not induced in mice that did not express human tau. Assuming that tau pathology wasn't elicited by some indirect pathway (some mice overexpressing mutated human tau develop protein tangles even when exposed to un related amyloid aggregates14), this sequence of events is reminiscent of prions. Finally, Frost and colleagues5 show that extracellular tau aggregates can be taken up by cells in culture. Hence, tau can attack and penetrate cells from the outside, sporting predatory behaviour akin to that of prions.

Yet there is one crucial difference between actual prion diseases and diseases caused by other prion-like proteins (let's call them prionoids) described so far (see table). The behaviour of prions is entirely comparable to that of any other infectious agent: for instance, prions are transmissible between individuals and often across species, and can be assayed with classic microbiological techniques, including titration by bioassay. Accordingly, prion diseases were long thought to be caused by viruses, and BSE created a worldwide panic similar to that currently being provoked by influenza. By contrast, although prionoids can 'infect' neighbouring molecules and sometimes even neighbouring cells, they do not spread within communities or cause epidemics such as those seen with BSE.

So, should any amyloid deserve an upgrade to a bone fide prion status? Currently, amyloid A (AA) amyloidosis may be the most promising candidate for a truly infectious disease caused by a self-propagating protein other than PrPSc. AA amyloid consists of orderly aggregated fragments of the SAA protein, and its deposition damages many organs of the body. Seeds of AA amyloid can be excreted in faeces15, and can induce amyloidosis if taken up orally (at least in geese)16. Also, AA amyloid may be transmitted between mice by transfusion of white blood cells17. So, like entero viruses and, perhaps, sheep scrapie prions, AA amyloid seems to display all the elements of a complete infectious life cycle, including uptake, replication and release from its host.

There are intriguing evolutionary implications to the above findings. If prionoids are ubiquitous, why didn't evolution erect barriers to their pervasiveness? Maybe it is because the molecular transmissibility of aggregated states can sometimes be useful. Indeed, aggregation of the Sup35 protein, which leads to a prion-like phenomenon in yeast, may promote evolutionary adaptation by allowing yeast cells to temporarily activate DNA sequences that are normally untranslated18. Mammals have developed receptors for aggregates, and ironically PrPC may be one of them19, although these receptors have not been reported to mediate protective functions. Therefore, we shouldn't be shocked if instances of beneficial prionoids emerge in mammals as well. ¦

Adriano Aguzzi is at the Institute of Neuropathology, University Hospital of Zurich, CH-8091 Zurich, Switzerland. e-mail:

1. Griffith, J. S. Nature 215, 1043-1044 (1967). 2. Prusiner, S. B. Science 216, 136-144 (1982). 3. Ren, P.-H. et al. Nature Cell Biol. 11, 219-225 (2009). 4. Clavaguera, F. et al. Nature Cell Biol. doi:10.1038/ncb1901 (2009). 5. Frost, B., Jacks, R. L. & Diamond, M. I. J. Biol. Chem. 284, 12845-12852 (2009). 6. Castilla, J., Saá, P., Hetz, C. & Soto, C. Cell 121, 195-206 (2005). 7. Sigurdson, C. J. et al. Proc. Natl Acad. Sci. USA 106, 304-309 (2009). 8. Aguzzi, A. & Polymenidou, M. Cell 116, 313-327 (2004). 9. Manuelidis, E. E. et al. Proc. Natl Acad. Sci. USA 85, 4898-4901 (1988). 10. Kane, M. D. et al. J. Neurosci. 20, 3606-3611 (2000). 11. Meyer-Luehmann, M. et al. Science 313, 1781-1784 (2006). 12. Li, J.-Y. et al. Nature Med. 14, 501-503 (2008). 13. Chiti, F. & Dobson, C. M. Annu. Rev. Biochem. 75, 333-366 (2006). 14. GÖtz, J., Chen, F., van Dorpe, J. & Nitsch, R. M. Science 293, 1491-1495 (2001). 15. Zhang, B. et al. Proc. Natl Acad. Sci. USA 105, 7263-7268 (2008). 16. Solomon, A. et al. Proc. Natl Acad. Sci. USA 104, 10998-11001 (2007). 17. Sponarova, J., NystrÖm, S. N. & Westermark, G. T. PLoS ONE 3, e3308 (2008). 18. True, H. L. & Lindquist, S. L. Nature 407, 477-483 (2000). 19. Laurén, J. et al. Nature 457, 1128-1132 (2009).


Disease Protein Molecular transmissibility Infectious life cycle Prion diseases PrPSc Yes Yes Alzheimer's disease Amyloid-ß Yes Not shown Tauopathies Tau Yes Not shown Parkinson's disease a-Synuclein Host-to-graft Not shown AA amyloidosis Amyloid A Yes Possible Huntington's disease Polyglutamine Yes Not shown Phenotype Protein Molecular transmissibility Infectious life cycle Suppressed translational termination (yeast) Sup35 Yes Not shown Heterokaryon incompatibility (filamentous fungi) Het-s Yes Not shown Biofilm promotion (bacteria) CsgA Yes Not shown In humans and animals, infectious prion diseases are caused by PrPSc, which spreads by recruiting its monomeric precursor PrPC into aggregates. Aggregates then multiply by breakage, a process that is termed molecular transmissibility. Other proteins involved in disease and in phenotypes of fungi and bacteria, can also undergo self-sustaining aggregation, but none of these 'prionoid' proteins behaves like typical infectious agents, nor do any of them enact a complete infectious life cycle - with the possible exception of AA amyloid. Correction In the News & Views article "Immunology: Immunity's ancient arms" by Gary W. Litman and John P. Cannon (Nature 459, 784-786; 2009), the name of the fi rst author of the Nature paper under discussion was misspelt. The author's name is P. Guo, not Gou as published.

© 2009 Macmillan Publishers Limited. All rights reserved

Thursday, February 26, 2009

'Harmless' prion protein linked to Alzheimer's disease Non-infectious form of prion protein could cause brain degeneration ???



CJD1/9 0185

Ref: 1M51A



1. CMO will wish to be aware that a meeting was held at DH yesterday, 4 January, to discuss the above findings. It was chaired by Professor Murray (Chairman of the MRC Co-ordinating Committee on Research in the Spongiform Encephalopathies in Man), and attended by relevant experts in the fields of Neurology, Neuropathology, molecular biology, amyloid biochemistry, and the spongiform encephalopathies, and by representatives of the MRC and AFRC.

2. Briefly, the meeting agreed that:

i) Dr Ridley et als findings of experimental induction of p amyloid in primates were valid, interesting and a significant advance in the understanding of neurodegeneradve disorders;

ii) there were no immediate implications for the public health, and no further safeguards were thought to be necessary at present; and

iii) additional research was desirable, both epidemiological and at the molecular level. Possible avenues are being followed up by DH and the MRC, but the details will require further discussion.


Regarding Alzheimer's disease

(note the substantial increase on a yearly basis)


The pathogenesis of these diseases was compared to Alzheimer's disease at a molecular level...


And NONE of this is relevant to BSE?

There is also the matter whether the spectrum of ''prion disease'' is wider than that recognized at present.


BSE101/1 0136


5 NOV 1992

CMO From: Dr J S Metters DCMO 4 November 1992


also, see the increase of Alzheimer's from 1981 to 1986

Occasional PrP plaques are seen in cases of Alzheimer's Disease


full text;

Tuesday, August 26, 2008

Alzheimer's Transmission of AA-amyloidosis: Similarities with Prion Disorders NEUROPRION 2007 FC4.3

see full text ;

Alzheimer's and CJD



Terry S. Singeltary Sr. P.O. Box 42 Bacliff, Texas USA