TY - JOUR
T1 - Kinetic analysis of aggregated amyloid-β peptide clearance in adult bone-marrow-derived macrophages from APP and CCL2 transgenic mice
AU - Yamamoto, Masaru
AU - Kiyota, Tomomi
AU - Walsh, Shannon M.
AU - Ikezu, Tsuneya
N1 - Funding Information:
Acknowledgements We thank Dr. K. Ashe for providing Tg2576 mice; Dr. Richard Ransohoff for providing JE-95 mice; Dr. Y. Enose for the instruction of tissue culture; Dr. J. Kipnis for critical reading of the manuscript; and J. Buescher for editing, animal maintenance, and genotyping. This work is supported by Vada Oldfield Alzheimer Research Foundation and NIH NS043985 (TI).
PY - 2007/6
Y1 - 2007/6
N2 - Accumulating evidence suggests that bone-marrow (BM)-derived mononuclear phagocytes have an important role in the clearance of soluble and aggregated amyloid-β peptides (Aβ) in Alzheimer's disease (AD) brains. However, the exact kinetics of Aβ clearance in mononuclear phagocytes derived from transgenic animal models of AD expressing β-amyloid precursor protein (APP) mutants have been poorly characterized. We have examined whether CCL2 and APP expression affects the clearance of Aβ in conjunction with our control, acetylated low-density lipoprotein (AcLDL), using primary cultured BM-derived macrophages derived from adult APP, CCL2, APP/CCL2, and control littermates. Pulse-chase analysis demonstrated three distinct destinations for Aβ40 and AcLDL: intracellular retention, degradation, and secretion. As predicted, 50% of Aβ remained intracellularly contained even 5 days after pulse, while 40% of degraded and 14% of nondegraded Aβ were secreted. APP/CCL2 macrophages show reduced intracellular Aβ retention, along with enhanced secretion of both degraded and nondegraded Aβ. Aβ accumulation in aggresome is also partially reduced in APP/CCL2 macrophages as compared to other APP, CCL2, or control groups, suggesting impaired sorting of aggregated Aβ in aggresomes. The degradation of intracranially injected 125I-Aβ40 aggregates was also enhanced in adult APP/CCL2 mice as compared to APP littermates in vivo. These data suggest that APP and CCL2 synergistically enhance BM-derived macrophage-mediated clearance of Aβ. In contrast, the clearance of AcLDL by BM-derived macrophages was not significantly enhanced by the presence of either APP or CCL2.
AB - Accumulating evidence suggests that bone-marrow (BM)-derived mononuclear phagocytes have an important role in the clearance of soluble and aggregated amyloid-β peptides (Aβ) in Alzheimer's disease (AD) brains. However, the exact kinetics of Aβ clearance in mononuclear phagocytes derived from transgenic animal models of AD expressing β-amyloid precursor protein (APP) mutants have been poorly characterized. We have examined whether CCL2 and APP expression affects the clearance of Aβ in conjunction with our control, acetylated low-density lipoprotein (AcLDL), using primary cultured BM-derived macrophages derived from adult APP, CCL2, APP/CCL2, and control littermates. Pulse-chase analysis demonstrated three distinct destinations for Aβ40 and AcLDL: intracellular retention, degradation, and secretion. As predicted, 50% of Aβ remained intracellularly contained even 5 days after pulse, while 40% of degraded and 14% of nondegraded Aβ were secreted. APP/CCL2 macrophages show reduced intracellular Aβ retention, along with enhanced secretion of both degraded and nondegraded Aβ. Aβ accumulation in aggresome is also partially reduced in APP/CCL2 macrophages as compared to other APP, CCL2, or control groups, suggesting impaired sorting of aggregated Aβ in aggresomes. The degradation of intracranially injected 125I-Aβ40 aggregates was also enhanced in adult APP/CCL2 mice as compared to APP littermates in vivo. These data suggest that APP and CCL2 synergistically enhance BM-derived macrophage-mediated clearance of Aβ. In contrast, the clearance of AcLDL by BM-derived macrophages was not significantly enhanced by the presence of either APP or CCL2.
KW - APP
KW - Beta-amyloid
KW - Bone marrow-macrophage
KW - CCL2
KW - Degradation
KW - Phagocytosis
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U2 - 10.1007/s11481-006-9049-8
DO - 10.1007/s11481-006-9049-8
M3 - Article
C2 - 18040846
AN - SCOPUS:34247512968
SN - 1557-1890
VL - 2
SP - 213
EP - 221
JO - Journal of Neuroimmune Pharmacology
JF - Journal of Neuroimmune Pharmacology
IS - 2
ER -