The Probiotic Yeast, Milmed, Promotes Autophagy and Antioxidant Pathways in BV-2 Microglia Cells and C. elegans

<b>Background:</b> 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 <i>Caenorhabditis elegans</i> (<i>C. elegans</i>) in restoring autophagic processes. <b>Methods:</b> BV-2 microglial cells were incubated with <i>S. cerevisiae</i> (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 <i>C. elegans</i> were measured by fluorescence microscopy. <b>Results:</b> Treatment with Milmed YPD cultured yeast or the dried powder obtained from it promoted autophagic flux, as shown by the increased expression of the <i>Beclin-1</i>, <i>ATG7</i>, <i>LC3</i>, and <i>p62</i> mRNAs and the inhibition of mTOR, as evaluated by ELISA. It also enhanced the antioxidant response by increasing the expression of <i>NRF2</i>, <i>SOD1</i>, and <i>GPX</i>; moreover, pNRF2 expression compared with cytosolic NRF2 expression was enhanced, as shown by immunofluorescence. Milmed dietary supplementation prolonged the survival of <i>C. elegans</i> and reduced the age-related ROS accumulation without changing the expression of <i>gst-4.</i> The pro-longevity effect was found to be dependent on SKN-1/Nrf2 activation, as shown by the absence of benefit in <i>skn-1</i> mutants. <b>Conclusions:</b> Milmed yeast demonstrates significant pro-autophagy and antioxidant activity with significant pro-longevity effects in <i>C. elegans</i>, 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.