Title: PhIP exposure in rodents produces neuropathology potentially relevant to Alzheimer's disease.

Authors: Syeda, Tauqeerunnisa; Foguth, Rachel M; Llewellyn, Emily; Cannon, Jason R

Published In Toxicology, (2020 05 15)

Abstract: Alzheimer's disease (AD) is a public health crisis due to debilitating cognitive symptoms and lack of curative treatments, in the context of increasing prevalence. Thus, it is critical to identify modifiable risk factors. High levels of meat consumption may increase AD risk. Many toxins are formed during meat cooking such as heterocyclic aromatic amines (HAAs). Our prior studies have shown that HAAs produce dopaminergic neurotoxicity. Given the mechanistic and pathological overlap between AD and dopaminergic disorders we investigated whether exposure to 2-amino-1-methyl-6-phenylimidazo [4,5-b] pyridine (PhIP), a prevalent dietary HAA formed during high-temperature meat cooking, may produce AD-relevant neurotoxicity. Here, C57BL/6 mice were treated with 100 or 200 mg/kg PhIP for 8 h or 75 mg/kg for 4 weeks and 16 weeks. PhIP exposure for 8 h produced oxidative damage, and AD-relevant alterations in hippocampal synaptic proteins, Amyloid-beta precursor protein (APP), and β-Site amyloid precursor protein cleaving enzyme 1 (BACE1). PhIP exposure for 4 weeks resulted in an increase in BACE1. PhIP exposure for 16 weeks resulted in increased hippocampal oxidative damage, APP, BACE1, Aβ aggregation, and tau phosphorylation. Quantification of intracellular nitrotyrosine revealed oxidative damage in cholinergic neurons after 8 h, 4 weeks and 16 weeks of PhIP exposure. Our study demonstrates that increase in oxidative damage, APP and BACE1 might be a possible mechanism by which PhIP promotes Aβ aggregation. Given many patients with AD or PD exhibit neuropathological overlap, our study suggests that HAA exposure should be further studied for roles in mediating pathogenic overlap.

PubMed ID: 32169473

MeSH Terms: Alzheimer Disease/chemically induced; Alzheimer Disease/metabolism; Alzheimer Disease/pathology*; Amyloid Precursor Protein Secretases/metabolism; Amyloid beta-Peptides/metabolism; Amyloid beta-Protein Precursor/metabolism; Animals; Aspartic Acid Endopeptidases/metabolism; Disease Models, Animal; Disease Progression; Food Contamination*; Hippocampus/metabolism; Hippocampus/pathology*; Imidazoles*; Male; Mice, Inbred C57BL; Neurons/metabolism; Neurons/pathology*; Oxidative Stress; Phosphorylation; Protein Aggregation, Pathological; Time Factors; tau Proteins/metabolism