Ergosterol promotes neurite outgrowth, inhibits amyloid-beta synthesis, and extends longevity: In vitro neuroblastoma and in vivo Caenorhabditis elegans evidence.

AIMS: Alzheimer's disease (AD), the most common neurodegenerative disorder associated with aging, is characterized by amyloid-β (Aβ) plaques in the hippocampus. Ergosterol, a mushroom sterol, exhibits neuroprotective activities; however, the underlying mechanisms of ergosterol in promoting neurite outgrowth and preventing Aβ-associated aging have never been investigated. We aim to determine the beneficial activities of ergosterol in neuronal cells and Caenorhabditis elegans (C. elegans).

MATERIALS AND

METHODS

The neuritogenesis and molecular mechanisms of ergosterol were investigated in wild-type and Aβ precursor protein (APP)-overexpressing Neuro2a cells. The anti-amyloidosis properties of ergosterol were determined by evaluating in vitro Aβ production and the potential inhibition of Aβ-producing enzymes. Additionally, AD-associated transgenic C. elegans was utilized to investigate the in vivo attenuating effects of ergosterol.

KEY FINDINGS: Ergosterol promoted neurite outgrowth in Neuro2a cells through the upregulation of the transmembrane protein Teneurin-4 (Ten-4) mRNA and protein expressions, phosphorylation of the extracellular signal-regulated kinases (ERKs), activity of cAMP response element (CRE), and growth-associated protein-43 (GAP-43). Furthermore, ergosterol enhanced neurite outgrowth in transgenic Neuro2A cells overexpressing either the wild-type APP (Neuro2a-APPwt) or the Swedish mutant APP (Neuro2a-APPswe) through the Ten-4/ERK/CREB/GAP-43 signaling pathway. Interestingly, ergosterol inhibited Aβ synthesis in Neuro2a-APPwt cells. In silico analysis indicated that ergosterol can interact with the catalytic sites of β- and γ-secretases. In Aβ-overexpressing C. elegans, ergosterol decreased Aβ accumulation, increased chemotaxis behavior, and prolonged lifespan.

SIGNIFICANCE: Ergosterol is a potential candidate compound that might benefit AD patients by promoting neurite outgrowth, inhibiting Aβ synthesis, and enhancing longevity.