PMID- 29858247 OWN - NLM STAT- MEDLINE DCOM- 20190204 LR - 20210317 IS - 1083-351X (Electronic) IS - 0021-9258 (Print) IS - 0021-9258 (Linking) VI - 293 IP - 29 DP - 2018 Jul 20 TI - Full-length amyloid precursor protein regulates lipoprotein metabolism and amyloid-beta clearance in human astrocytes. PG - 11341-11357 LID - S0021-9258(20)31559-3 [pii] LID - 10.1074/jbc.RA117.000441 [doi] AB - Mounting evidence suggests that alterations in cholesterol homeostasis are involved in Alzheimer's disease (AD) pathogenesis. Amyloid precursor protein (APP) or multiple fragments generated by proteolytic processing of APP have previously been implicated in the regulation of cholesterol metabolism. However, the physiological function of APP in regulating lipoprotein homeostasis in astrocytes, which are responsible for de novo cholesterol biosynthesis and regulation in the brain, remains unclear. To address this, here we used CRISPR/Cas9 genome editing to generate isogenic APP-knockout (KO) human induced pluripotent stem cells (hiPSCs) and differentiated them into human astrocytes. We found that APP-KO astrocytes have reduced cholesterol and elevated levels of sterol regulatory element-binding protein (SREBP) target gene transcripts and proteins, which were both downstream consequences of reduced lipoprotein endocytosis. To elucidate which APP fragments regulate cholesterol homeostasis and to examine whether familial AD mutations in APP affect lipoprotein metabolism, we analyzed an isogenic allelic series harboring the APP Swedish and APP V717F variants. Only astrocytes homozygous for the APP Swedish (APP(Swe/Swe)) mutation, which had reduced full-length APP (FL APP) due to increased beta-secretase cleavage, recapitulated the APP-KO phenotypes. Astrocytic internalization of beta-amyloid (Abeta), another ligand for low-density lipoprotein (LDL) receptors, was also impaired in APP-KO and APP(Swe/Swe) astrocytes. Finally, impairing cleavage of FL APP through beta-secretase inhibition in APP(Swe/Swe) astrocytes reversed the LDL and Abeta endocytosis defects. In conclusion, FL APP is involved in the endocytosis of LDL receptor ligands and is required for proper cholesterol homeostasis and Abeta clearance in human astrocytes. CI - (c) 2018 by The American Society for Biochemistry and Molecular Biology, Inc. FAU - Fong, Lauren K AU - Fong LK AD - Department of Cellular and Molecular Medicine, University of California at San Diego, La Jolla, California 92093; Sanford Consortium for Regenerative Medicine, La Jolla, California 92093. FAU - Yang, Max M AU - Yang MM AD - Department of Cellular and Molecular Medicine, University of California at San Diego, La Jolla, California 92093; Sanford Consortium for Regenerative Medicine, La Jolla, California 92093. FAU - Dos Santos Chaves, Rodrigo AU - Dos Santos Chaves R AD - Department of Cellular and Molecular Medicine, University of California at San Diego, La Jolla, California 92093; Sanford Consortium for Regenerative Medicine, La Jolla, California 92093. FAU - Reyna, Sol M AU - Reyna SM AD - Department of Cellular and Molecular Medicine, University of California at San Diego, La Jolla, California 92093; Sanford Consortium for Regenerative Medicine, La Jolla, California 92093. FAU - Langness, Vanessa F AU - Langness VF AD - Department of Cellular and Molecular Medicine, University of California at San Diego, La Jolla, California 92093; Sanford Consortium for Regenerative Medicine, La Jolla, California 92093. FAU - Woodruff, Grace AU - Woodruff G AD - Department of Cellular and Molecular Medicine, University of California at San Diego, La Jolla, California 92093; Sanford Consortium for Regenerative Medicine, La Jolla, California 92093. FAU - Roberts, Elizabeth A AU - Roberts EA AD - Department of Cellular and Molecular Medicine, University of California at San Diego, La Jolla, California 92093; Sanford Consortium for Regenerative Medicine, La Jolla, California 92093. FAU - Young, Jessica E AU - Young JE AD - Department of Cellular and Molecular Medicine, University of California at San Diego, La Jolla, California 92093; Department of Pathology and Institute of Stem Cell and Regenerative Medicine, University of Washington, Seattle, Washington 98195. FAU - Goldstein, Lawrence S B AU - Goldstein LSB AD - Department of Cellular and Molecular Medicine, University of California at San Diego, La Jolla, California 92093; Sanford Consortium for Regenerative Medicine, La Jolla, California 92093; Department of Neurosciences, University of California at San Diego, La Jolla, California 92093. Electronic address: lgoldstein@ucsd.edu. LA - eng GR - P50 AG005131/AG/NIA NIH HHS/United States GR - RF1 AG048083/AG/NIA NIH HHS/United States GR - T32 GM008666/GM/NIGMS NIH HHS/United States PT - Journal Article PT - Research Support, N.I.H., Extramural PT - Research Support, Non-U.S. Gov't DEP - 20180601 PL - United States TA - J Biol Chem JT - The Journal of biological chemistry JID - 2985121R RN - 0 (Amyloid beta-Peptides) RN - 0 (Amyloid beta-Protein Precursor) RN - 0 (LDLR protein, human) RN - 0 (Lipoproteins) RN - 0 (Receptors, LDL) RN - 0 (Sterol Regulatory Element Binding Proteins) RN - 97C5T2UQ7J (Cholesterol) SB - IM MH - Amyloid beta-Peptides/*metabolism MH - Amyloid beta-Protein Precursor/genetics/*metabolism MH - Astrocytes/cytology/*metabolism MH - CRISPR-Cas Systems MH - Cell Line MH - Cholesterol/*metabolism MH - Endocytosis MH - Humans MH - Induced Pluripotent Stem Cells/cytology/metabolism MH - Lipoproteins/*metabolism MH - Receptors, LDL/metabolism MH - Sterol Regulatory Element Binding Proteins/metabolism PMC - PMC6065173 OTO - NOTNLM OT - Alzheimer disease OT - amyloid precursor protein (APP) OT - amyloid-beta (Abeta) OT - astrocyte OT - cholesterol metabolism OT - induced pluripotent stem cell (iPS cell) (iPSC) OT - lipoprotein metabolism OT - lipoprotein receptor COIS- The authors declare that they have no conflicts of interest with the contents of this article EDAT- 2018/06/03 06:00 MHDA- 2019/02/05 06:00 PMCR- 2019/07/20 CRDT- 2018/06/03 06:00 PHST- 2017/10/14 00:00 [received] PHST- 2018/05/11 00:00 [revised] PHST- 2018/06/03 06:00 [pubmed] PHST- 2019/02/05 06:00 [medline] PHST- 2018/06/03 06:00 [entrez] PHST- 2019/07/20 00:00 [pmc-release] AID - S0021-9258(20)31559-3 [pii] AID - RA117.000441 [pii] AID - 10.1074/jbc.RA117.000441 [doi] PST - ppublish SO - J Biol Chem. 2018 Jul 20;293(29):11341-11357. doi: 10.1074/jbc.RA117.000441. Epub 2018 Jun 1.