Effects and mechanisms of lifespan extension and healthspan promotion induced by <i>Limosilactobacillus reuteri</i> (<i>Lactobacillus reuteri</i>) A21041.

<h4>Background</h4>Nowadays probiotics have been widely used in the fields of food, medicine and agriculture. In this study, we investigated the anti-aging effects of the probiotic strain of <i>Limosilactobacillus reuteri</i> A21041 using <i>Caenorhabditis elegans</i>.<h4>Methods</h4>In this study, lifespan assays, lipid storage experiments, motility tests and stress resistance assays were conducted using <i>C. elegans</i> to present the differences between A21041 and control group <i>Escherichia coli</i> OP50. Besides, transcriptome sequencing and non-targeted metabolomics analysis were performed to further reveal the mechanism of A21041-mediated lifespan prolongation.<h4>Results</h4>We found that A21041 extended the lifespan of nematodes by 19.27% compared with the control group, and reduced lipid accumulation of <i>C. elegans</i> by 54.47% in day 5 and 68.77% in day 7 via lysosome signaling pathway. In addition, A21041 increased the viability of worms under thermal stimulus through up-regulation of <i>hsp-16.2</i> and <i>hsp-110</i> mRNA levels. Meanwhile, A21041 feeding activated superoxide dismutase (SOD) and enhanced antioxidative ability of nematodes. Of impoatance, A21041 did not extend the lifespan of loss-in function mutants of <i>daf-2</i>, <i>akt-2</i> and <i>aak-2</i>, which suggested that insulin/IGF-1 signaling (IIS) were required for the life-extending effect of A21041. RNA-seq analysis was consistent with our findings above. Gene <i>gst-4</i>, which has been confirmed to be highly associated with antioxidant activity and lifespan extension was significantly up-regulated. And RNA sequencing still revealed that ATF-4/CTH-2/H2S pathway might be related to A21041-mediated longevity. Metabolites analysis presented that many metabolites produced by A21041 could protect worms from various damages such as oxidants, inflammatory factors and etc.<h4>Conclusion</h4>In conclusion, our results demonstrated that <i>L. reuteri</i> A21041 was able to prolong the lifespan and promote the healthspan(definition) of <i>Caenorhabditis elegans</i>.