3.7 DACA exerts neuroprotective effects by regulating Nrf2.
We conducted experiments to evaluate the dependence of DACA-induced neuroprotection on Nrf2 activation and the involvement of p62 in the pathway of Nrf2 activation by DACA. ML385, a specific NRF2 inhibitor, and K67, a competitive binder of p62 to Keap1 that restores Keap1-driven degradation of Nrf2 ubiquitination, were employed to investigate the mechanism underlying DACA-mediated Nrf2 expression[28-30]. The use of Nrf2 inhibitors (ML385) in cell viability tests revealed that the protective effect of DACA against MPP+ toxicity was abolished, indicating that Nrf2 activation is essential for DACA’s neuroprotective effects. Additionally, in the presence of K67, there was a reduction in the neuroprotective capacity of DACA (Fig. 7A).
To further validate the involvement of DACA in Nrf2 activation, we assessed the intracellular levels of p62, Nrf2, and their downstream proteins. Western blot analysis revealed that ML385 effectively attenuated DACA-induced Nrf2 activation while concurrently reducing the expression of HO-1, GCLC, and GCLM (Fig. 7B-D). Conversely, K67 failed to impede Nrf2 activation (Fig. 7B-D), suggesting that p62 is not a prerequisite for DACA-mediated Nrf2 activation.