The modulatory effects of Hericium erinaceus and donepezil on amyloid accumulation and autophagy-associated clearance in Aβ1-42-induced N2a cells

Background and objective: Alzheimers disease involves imbalanced amyloid-{beta} (A {beta}) production and clearance, supporting investigation of adjuncts to symptomatic treatment. This study evaluated whether methanolic Hericium erinaceus extract could support recovery after A{beta}1-42-induced injury, alone and with donepezil, through modulation of {beta}-secretase (BACE1) activity or autophagy-associated clearance. Methods: Extract composition and BACE1 inhibition were assessed using liquid chromatography-mass spectrometry (LC-MS) and a fluorescence resonance energy transfer assay, respectively. Neuro-2a cells exposed to A{beta}1-42 (2.42 M) for 6 hours received individual or combined treatments for 24 hours. Cell viability was assessed using WST-1, combination interactions using Bliss independence and protein responses using Western blotting with paired bafilomycin A1 conditions across three independent experiments. Results: LC-MS identified ergothioneine and trace hericenone D. The extract produced an apparent concentration-dependent BACE1-inhibitory response (IC50, 69.97 {+/-} 36.10 g/mL) and significantly increased post-injury viability at 40g/mL (150.2 {+/-} 12.11% of the A {beta} induced control; p = 0.0070). Although the full combination matrix was predominantly additive (Bliss score, 1.95), 51.1 M donepezil with 24.9 g/mL extract produced local synergy (score, 34.29) and the highest observed viability. This pair showed the most coordinated directional protein pattern, with lower mean levels of amyloid precursor protein, A{beta}, and BACE1, and p62/A {beta} accumulation following lysosomal blockade. Western blot differences were not statistically significant. Conclusion: These integrated findings support H. erinaceus as a candidate adjunct to donepezil, with possible complementary effects on amyloidogenic processing and intracellular clearance. Further validation of autophagic flux is needed to confirm the proposed dual response. Keywords: Hericium erinaceus; donepezil; BACE1; amyloid- {beta} ; autophagy; combination treatment