Proteolytic processing of Alzheimer's disease amyloid precursor protein (APP) by /3-secretase generates the Nterminus ofA/3 (which deposits in the brain) and releases a secreted ectodomain of APP (sAPP/3). We identified in human platelets a band at 125 kDa corresponding to APP ectodomain ending with C-terminal methionine residue (APP671) as characterized by an antibody specificfor the C-terminal methionine residue of sAPP/3. The same antibody also detected bands at -105 and U125 kDa in human brain homogenates. Platelet sAPP/3 is an isoform containing the Kunitzprotease inhibitor domain (sAPP/3-KPI+) and is released into the medium when platelets are induced to aggregate using agonists such as thrombin, collagen, phorbol 12-myristate 13-acetate, or calcium ionophore A2318 7. The release of sAPPB /from aggregatedplatelets is consistent with a role in regulation of the coagulation cascade and/or in platelet aggregation. These data together with previous reports suggest that human platelets contain the a-, /3-and y-secretase activities, and are a suitable system to study APP processing and Ap production, a pathway which is considered to be a prime targetfor therapeutic intervention in AD.
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References
1.
1. Kang J, Lemaire H, Unterbeck A, et al: The precursor of Alzheimer's disease amyloid A4 protein resembles a cell-surface receptor. Nature. 1987; 325: 733-736.
2.
2. Kitaguchi N, Takahashi Y, Tokushima Y, et al: Novel precursor of Alzheimer's disease amyloid protein shows protease inhibitory activity. Nature. 1988; 331: 530-532.
3.
3. Ponte P, Gonzalez-DeWhitt P, Schilling J, et al: A new A4 amyloid mRNA contains a domain homologous to serine proteinase inhibitors. Nature. 1988; 331: 525-527.
4.
4. Tanzi RE, McClatchey Al, Lamperti ED, et al: Protease inhibitor domain encoded by an amyloid protein precursor mRNA associated with Alzheimer's disease. Nature. 1988; 331: 528-530.
5.
5. Golde TE, Estus S, Usiak M, et al: Expression of P amyloid protein precursor mRNAs: recognition of a novel alternatively spliced form and quantitation in Alzheimer's disease using PCR. Neuron. 1990; 4: 253-267.
6.
6. Li QX, Berndt MC, Bush Al, et al: Membrane-associated forms of the PA4 amyloid protein precursor of Alzheimer's disease in human platelet and brain: surface expression on the activated human platelet. Blood. 1994; 84: 133-142.
7.
7. Hardy J: Amyloid, the presenilins and Alzheimer's disease. Trends Neurosci.1997; 20: 154-159.
8.
8. Cai X, Golde TE, Younkin SG: Release of excess amyloid 3 protein from a mutant amyloid f protein precursor. Science. 1993; 259: 514-516.
9.
9. Citron M, Oltersdorf T, Haass C, et al: Mutation of the P-amyloid precursor protein in familial Alzheimer's disease increases f3-protein production. Nature. 1992; 360: 672-674.
10.
10. Haass C, Hung AH, Selkoe DJ, et al: Mutations associated with a locus for familial Alzheimer's disease result in alternative processing of amyloid P-protein precursor. J. Biol. Chem.1994; 269: 17741-17748.
11.
11. Suzuki N, Cheung TT, Cai XD, et al: An increased percentage of long amyloid D protein secreted by familial amyloid f protein precursor (PAPP717) mutants. Science. 1994; 264: 1336-1340.
12.
12. Mann DMA, Iwatsubo T, Ihara Y, et al: Predominant deposition of amyloid-342(43) in plaques in cases of Alzheimer's disease and hereditary cerebral hemorrhage associated with mutations in the amyloid precursor protein gene. Am. J. Pathol. 1996; 148: 1257-1266.
13.
13. Mann DMA, Brown A, Prinja D, et al: An analysis of the morphology of senile plaques in Down's syndrome patients of different ages using immunocytochemical and lectin histochemical techniques. Neuropathol. Appl. Neurobiol. 1989; 15: 317-329.
14.
14. Tanzi R, Kovacs DM, Kim TW, et al: The gene defects responsible for familial Alzheimer's disease. Neurobiol. Dis.1996; 3: 159-168.
15.
15. Scheuner D, Eckman C, Jensen M, et al: Secreted amyloid β-protein similar to that in the senile plaques of Alzheimer's disease is increased in vivo by the presenilin I and 2 and APP mutations linked to familial Alzheimer's disease. Nat. Med.1996; 2: 864-870.
16.
16. Citron M, Westaway D, Xia W, et al: Mutant presenilins of Alzheimer's disease increase production of 42-residue amyloid 1-protein in both transfected cells and transgenic mice. Nat. Med.1997; 3: 67-72.
17.
17. Duff K, Eckman C, Zehr C, et al: Increased amyloid-342(43) in brains of mice expressing mutant presenilin 1. Natutr-e. 1996; 383: 710-713.
18.
18. Esch FS, Keim PS, Beattie EC, et at: Cleavage of amyloid P peptide during constitutive processing of its precursor. Science. 1990; 248: 1122-1124.
19.
19. Sisodia SS, Koo EH, Beyreuther K, et at: Evidence that P-amyloid protein in Alzheimer's disease is not derived by normal processing. Science. 1990; 248: 492-495.
20.
20. Weidemann A, Kdnig G, Bunke D, et at: Identification, biogenesis and localization of precursors of Alzheimer's disease A4 amyloid protein. Cell. 1989; 57: 115-126.
21.
21. Haass C, Schlossmacher MG, Hung AY, et at: Amyloid P-peptide is produced by cultured cells during normal metabolism. NVature. 1992; 359: 322-325.
22.
22. Shoji M, Golde TE, Ghiso J, et at: Production of the Alzheimer amyloid 1 protein by normal proteolytic processing. Science. 1992; 258: 126-129.
23.
23. Haass C, Hung AY, Schlossmacher MG, et at: f-amyloid peptide and a 3-kDa fragment are derived by distinct cellular mechanisms. J. Biol. Chem.1993; 268: 3021-3024.
24.
24. Fuller SJ, Storey E, Li QX, et at: Intracellular production of PA4 amyloid of Alzheimer's disease: Modulation by phosphoramidon and lack of coupling to the secretion of the amyloid precursor. Biochemistiy. 1995; 34: 8091-8098.
25.
25. Seubert P, Vigo-Pelfrey C, Esch F, et at: Isolation and quantification of soluble Alzheimer's 3-peptide from biological fluids. Nature. 1992; 359: 325-327.
26.
26. Evin G, Beyreuther K, Masters CL: Alzheimer's disease amyloid precursor protein (APPP): Proteolytic processing, secretases and fA4 amyloid production [review]. AmI'loid. Int. J. Exp. Clini. Invest. 1994; 1: 263-280.
27.
27. Bush Al, Martins RN, Rumble B, et at: The amyloid precursor protein of Alzheimer's disease is released by human platelets. J. Biol. Chem.1990; 265: 15977-15983.
29. Smith RP, Broze GJ, Jr.: Characterization of platelet-releasable forms of P-amyloid precursor proteins: The effect of thrombin. Blood. 1992; 80: 2252-2260.
30.
30. Van Nostrand WE, Schmaier AH, Farrow JS, et at: Protease nexin-2/amyloid 3-protein precursor in blood is a platelet-specific protein. Biochem. Biophys. Res. Commun.1991; 175: 15-21.
31.
31. Smith RP, Higuchi DA, Broze GJ, Jr.: Platelet coagulation factor XIa-inhibitor, a form of Alzheimer amyloid precursor protein. Science. 1990; 248: 1126-1128.
32.
32. Li QX, Evin G, Small DH, et at: Proteolytic processing of Alzheimer's disease PA4 amyloid precursor protein in human platelets. J. Biol. Chem.1995; 270: 14140-14147.
33.
33. Chen M, lnestrosa NC, Ross GS, et at: Platelets are the primary source of amyloid P-peptide in human blood. Biochem. Biophvs. Res. Commun.1995; 213: 96-103.
34.
34. Li Q-X, Whyte S, Tanner JE, et at: Secretion of Alzheimer's disease AP amyloid peptide by activated human platelets. Lab. Invest. 1998; 78: 461-469.
35.
35. Wisniewski HM, Frackowiak J, Zoltowska A, et at: Vascular 1-amyloid in Alzheimer's disease angiopathy is produced by proliferating and degenerating smooth muscle cells. Amvloid: Int. J Exp. Clin. Invest. 1994; 1: 8-16.
36.
36. Frackowiak J, Zoltowska A, Wisniewski HM: Non-fibrillar 1-amyloid protein is associated with smooth muscle cells of vessel walls in Alzheimer disease. J. Neuropathol. Exp. Neurol. 1994; 53: 637-645.
37.
37. Hilbich C, Mdnning U, Grund C, et al: Amyloid-like properties of peptides flanking the epitope of amyloid precursor protein-specific monoclonal antibody 22C11. J.Biol.Chem.1993; 268: 26571-26577.
38.
38. Buxbaum JD, Gandy SE, Cicchetti P, et al: Processing of Alzheimer P/A4 amyloid precursor protein: modulation by agents that regulate protein phosphorylation. Proc. Natl. Acad. Sci. USA.1990; 87: 6003-6006.
39.
39. Kim KS, Wen GY, Bancher C, et al: Detection and quantitation of amyloid 0-peptide with 2 monoclonal antibodies. Neurosci. Res. Commun.1990; 7: 113-122.
40.
40. Ida N, Hartmann T, Pantel J, et al: Analysis of heterogeneous PA4 peptides in human cerebrospinal fluid and blood by a newly developed sensitive western blot assay. J. Biol. Chem.1996; 271: 22908-22914.
41.
41. Moir RD, Martins RN, Small DH, et al: Human brain PA4 amyloid protein precursor (APP) of Alzheimer's disease: Purification and partial characterization. J. Neurochem.1992; 59: 1490-1498.
42.
42. Henry A, Masters CL, Beyreuther K, et al: Expression of human amyloid precursor protein ectodomains in Pichia pastoris: Analysis of culture conditions, purification, and characterization. Protein Expression and Purification. 1997; 10: 283-291.
43.
43. Sreekrishna K, Nelles L, Potenz R, et al: High-level expression, purification and characterization of recombinant human tumor necrosis factor synthesized in the methylotrophic yeast Pichia pastoris. Biochemistry. 1989; 28: 4117-4125.
44.
44. Li QX, Whyte S, Birchall I, et al: The amyloid protein precursor of Alzheimer's disease in human platelets and kidney. In: Non-neuronal cells in Alzheimer's disease, edited by Zatta P & Nicolini M. Singapore: World Scientific, 1995, p. 62-70.
45.
45. Schlossmacher MG, Ostaszewski BL, Hecker LI, et al: Detection 244 of distinct isoform patterns of the, B-amyloid precursor protein in human platelets and lymphocytes. Neurobiol. Aging. 1992; 13: 421-434.
46.
46. Davies TA, Long HJ, Rathbun WH, et al: Platelets from patients with Alzheimer's disease or other dementias exhibit disease-specific and apolipopreotein E correlatable defects. Amyloid: Int. J. Exp. Clin. Invest. 1996; 3: 13-19.
47.
47. Di Luca M, Pastorino L, Cattabeni F, et al: Abnormal pattern of platelet APP isoforms in Alzheimer disease and Down syndrome. Arch. Neurol. 1996; 53: 1162-1166.
48.
48. Rosenberg RN, Baskin F, Fosmire JA, et al: Altered amyloid protein processing in platelets of patients with Alzheimer disease. Arch. Neurol. 1997; 54: 139-144.
49.
49. Van Nostrand WE, Schmaier AH, Farrow JS, et al: Protease nexin-LI (amyloid n-protein precursor): A platelet a-granule protein. Science. 1990; 248: 745-748.
50.
50. Simons M, De Strooper B, Multhaup G, et al: Amyloidogenic processing of the human amyloid precursor protein in primary cultures of rat hippocampal neurons. J. Neurosci.1996; 16: 899-908.
51.
51. Ghiso J, Rostagno A, Gardella JE, et al: A 109-amino-acid C-terminal fragment of Alzheimer's-disease amyloid precursor protein contains a sequence, -RHDS-, that promotes cell adhesion. Biochem. J.1992; 288: 1053-1059.
52.
52. Saporito-Irwin SM, Van-Nostrand WE: Coagulation factor XIa cleaves the RDHS sequence and abolishes the cell adhesive properties of the amyloid P-protein. J. Biol. Chem.1995; 270: 26265-26269.
53.
53. Henry AH, Li QX, Galatis D, et al: Inhibition of platelet activation by the Alzheimer's disease amyloid precursor protein. British J Haematology. 1998; 103-103 (in press).
