One-year dietary supplementation with walnuts modifies exosomal miRNA in elderly subjects

Purpose Epidemiological studies and clinical trials support the association of nut consumption with a lower risk of prevalent non-communicable diseases, particularly cardiovascular disease. However, the molecular mechanisms underlying nut benefits remain to be fully described. MicroRNAs (miRNAs) are post-transcriptional regulators of gene expression and play a pivotal role in health and disease. Exosomes are extracellular vesicles released from cells and mediate intercellular communication. Whether nut consumption modulates circulating miRNAs (c-miRNAs) transported in exosomes is poorly described. Methods Cognitively healthy elderly subjects were randomized to either control (n = 110, abstaining from walnuts) or daily supplementation with walnuts (15% of their total energy, approximate to 30-60 g/day,n = 101) for 1-year. C-miRNAs were screened in exosomes isolated from 10 samples, before and after supplementation, and identified c-miRNA candidates were validated in the whole cohort. In addition, nanoparticle tracking analysis and lipidomics were assessed in pooled exosomes from the whole cohort. Results Exosomal hsa-miR-32-5p and hsa-miR-29b-3p were consistently induced by walnut consumption. No major changes in exosomal lipids, nanoparticle concentration or size were found. Conclusion Our results provide novel evidence that certain c-miRNAs transported in exosomes are modulated by walnut consumption. The extent to which this finding contributes to the benefits of walnuts deserves further research.

Automated summary

Nut consumption has been shown to modulate certain c-miRNAs transported in exosomes, further research is needed to determine the extent to which this finding contributes to the benefits of walnuts.