He-A, a new natural [4 + 2] adduct, protects against neuronal damage
through inhibiting ferroptosis via the Nrf2/SLC7A11 axis activation
Abstract
Background and Purpose: Neuroprotective strategy targeting ferroptosis
is currently considered a promising therapeutic approach for
neurodegenerative diseases (NDDs). Herpotrichones showed potential the
neuroprotective activity with low toxicity. The current study aimed to
find new herpotrichone neuroprotectants and investigate their
neuroprotective mechanism in vitro and in vivo. Experimental Approach:
Comprehensive separation methods were used to isolate new herpotrichone
analogues. The H2O2, RSL3, 6-OHDA-induced PC12 cells and LPS-induced
BV-2 cells were used to assess the potential neuroprotective effect of
compounds. UV-vis spectroscopy was used to determine the cell-free
antioxidant and iron-chelating capacity. Western blotting,
immunofluorescence, quantitative PCR, flow cytometry and enzyme-linked
immunosorbent assay (ELISA) were used to evaluate the activation of the
antioxidative elements and the regulation of the ferroptosis factors in
cell cultures and in zebrafish larvae. Key Results: Herpotrichone A
(He-A) and a new herpotrichone analogue with a new pentacyclic 6/6/6/6/3
skeleton exhibited significantly the neuroprotective effect in cell
cultures. He-A activated antioxidative elements and modulated SLC7A11
pathways. The decreased lipid ROS levels but increased GSH level showed
the anti-ferroptosis effect of He-A. The increased cell viability in
RSL3-induced PC12 cells and the improvement of locomotor in
6-OHDA-induced zebrafish larvae indicated that He-A possessed protective
ability against neuronal damage. Conclusion and Implications: This study
identifies a novel compound He-A that protects against neuronal damage
through activating Nrf2 pathway to upregulate antioxidative elements and
increasing the expressions of SLC7A11, FTL and FTH1 in vitro and in
vivo, which supports the development of He-A as a new neuroprotective
agent targeting ferroptosis.