Abstract
Background: Autophagy, a catabolic process essential for maintaining cellular homeostasis, declines with age and unhealthy lifestyles, contributing to neurodegenerative diseases. Probiotics, including Milmed yeast, have demonstrated anti-inflammatory and antioxidant properties. This study evaluated the activity of Milmed on BV-2 microglial cells in vitro and in the in vivo model of Caenorhabditis elegans (C. elegans) in restoring autophagic processes. Methods: BV-2 microglial cells were incubated with S. cerevisiae (Milmed treated yeast or untreated yeast) and then stimulated with lipopolysaccharide (LPS). mRNAs of the autophagic factors and antioxidant enzymes were assessed by qPCR; mTOR and NRF2 were evaluated by ELISA. pNRF2 compared with cytosolic NRF2 was evaluated by immunofluorescence. The longevity, body size, and reactive oxygen species (ROS) levels of C. elegans were measured by fluorescence microscopy. Results: Treatment with Milmed YPD cultured yeast or the dried powder obtained from it promoted autophagic flux, as shown by the increased expression of the Beclin-1, ATG7, LC3, and p62 mRNAs and the inhibition of mTOR, as evaluated by ELISA. It also enhanced the antioxidant response by increasing the expression of NRF2, SOD1, and GPX; moreover, pNRF2 expression compared with cytosolic NRF2 expression was enhanced, as shown by immunofluorescence. Milmed dietary supplementation prolonged the survival of C. elegans and reduced the age-related ROS accumulation without changing the expression of gst-4. The pro-longevity effect was found to be dependent on SKN-1/Nrf2 activation, as shown by the absence of benefit in skn-1 mutants. Conclusions: Milmed yeast demonstrates significant pro-autophagy and antioxidant activity with significant pro-longevity effects in C. elegans, thereby extending the lifespan and improving stress resistance, which, together with the previously demonstrated anti-inflammatory activity, highlights its role as a highly effective probiotic for its beneficial health effects. Activation of the SKN-1/NRF2 pathway and the modulation of autophagy support the therapeutic potential of Milmed in neuroprotection and healthy aging.