title: Endothelin-1 is elevated in Alzheimer's disease and upregulated by amyloid-β.
abstract: Vascular dysfunction and lowered cerebral blood flow are thought to contribute to the development and progression of Alzheimer's disease (AD). Endothelin-1 (ET-1) is a potent vasoconstrictor, the production of which is mainly catalyzed by endothelin-converting enzymes (ECEs). We previously showed that ECE-2 is upregulated by amyloid-β (Aβ), and its expression elevated in AD postmortem brain tissue. We have now investigated whether there is a concomitant increase in ET-1. We studied temporal cortex from 20 cases of sporadic AD and 20 matched controls. The cellular distribution of ET-1 was assessed immunohistochemically in paraffin sections. PreproET-1 (EDN1) mRNA and ET-1 protein were measured in homogenates of superior temporal cortex by real-time PCR and sandwich ELISA respectively. Cultured SH-SY5Y human neuroblastoma cells were incubated with 10 μM oligomeric Aβ42 for 24 h, and ET-1 protein level was measured in cell culture supernatants by sandwich ELISA. Antibody to ET-1 labeled neurons throughout the temporal cortex, and the walls of some cerebral blood vessels. ET-1 mRNA measured in the temporal neocortex was significantly elevated in AD when normalized for expression of GAPDH (p = 0.0256) or the neuronal marker neuron-specific enolase (NSE, p = 0.0001). ET-1 protein was also significantly higher in AD than in control tissue, when adjusted for neuronal content by measurement of NSE (p = 0.0275). ET-1 protein in SH-SY5Y cell supernatant rose 1.7-fold after exposure to 10 μM oligomeric Aβ (p = 0.024). These findings provide evidence of overactivity of the endothelin system in AD, further supporting the suggestion that endothelin receptor antagonists may be of value for the treatment of this disease.
authors.affiliation: Dementia ResearchGroup, School of Clinical Sciences, University of Bristol, Frenchay Hospital, Bristol, UK. jen.palmer@bristol.ac.uk
authors.forename: Jennifer C
authors.initials: JC
authors.lastname: Palmer
authors.forename: Rachel
authors.initials: R
authors.lastname: Barker
authors.forename: Patrick G
authors.initials: PG
authors.lastname: Kehoe
authors.forename: Seth
authors.initials: S
authors.lastname: Love
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000473:pathology; D016229:Amyloid beta-Peptides / Q000494:pharmacology; D016282:Aspartic Acid Endopeptidases / Q000378:metabolism; D016022:Case-Control Studies; D045744:Cell Line, Tumor; D019332:Endothelin-1 / Q000235:genetics / Q000378:metabolism*; D000072396:Endothelin-Converting Enzymes; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D008297:Male; D008666:Metalloendopeptidases / Q000378:metabolism; D008875:Middle Aged; D009447:Neuroblastoma / Q000473:pathology; D009474:Neurons / Q000378:metabolism; D010446:Peptide Fragments / Q000494:pharmacology; D010751:Phosphopyruvate Hydratase / Q000235:genetics / Q000378:metabolism; D011180:Postmortem Changes; D012333:RNA, Messenger / Q000378:metabolism; D013702:Temporal Lobe / Q000378:metabolism* / Q000473:pathology; D015854:Up-Regulation / Q000187:drug effects*
chemical_list: D016229:Amyloid beta-Peptides; D019332:Endothelin-1; D010446:Peptide Fragments; D012333:RNA, Messenger; C075222:amyloid beta-protein (1-42); D016282:Aspartic Acid Endopeptidases; D008666:Metalloendopeptidases; C000606924:ECE2 protein, human; D000072396:Endothelin-Converting Enzymes; D010751:Phosphopyruvate Hydratase