Human adipose stem cell-derived exosomes modulate the transcriptome of D-galactose-Induced neuronal cells

Abstract

Brain aging, which influences neurological function across cellular and molecular domains, is a critical concern in the elderly population. Therapeutic strategies for mitigating age-related neurodegeneration should target molecular pathways that are primarily involved in neuroinflammation. Exosomes derived from human adipose tissue mesenchymal stem cells (hASCs) have demonstrated anti-inflammatory and rejuvenating properties, making them promising agents for neurochemical intervention. However, their transcriptomic impact on neuronal cells remains largely unexplored. To address this research question, we applied high-throughput mRNA sequencing and downstream bioinformatic analysis. As an in vitro model for aging and neurodegeneration, CNS mouse-derived CAD cells were exposed to D-galactose (DG) to trigger molecular responses and were used to evaluate the efficacy of the isolated exosomes. The hASC-exosomes were isolated via ultrafiltration and subsequently characterized via nanoparticle tracking analysis, cryo-EM microscopy, and immunoassays. The internalization of PHK26-tagged hASC exosomes in the cytosol of the neuronal cells was monitored. Illumina-based mRNA sequencing has allowed expression profiling of more than 27,000 genes. Comparative transcriptomic profiling revealed 3951 differentially expressed genes (DEGs) associated with DG-induced cells and 3091 DEGs modulated by hASC-exosome treatment. In DG-treated cells, many genes were upregulated in response to cellular stress. The DEGs whose expression was upregulated in response to DG play roles in the DNA damage response, cellular senescence, and apoptosis. In the presence of hASC-derived exosomes, many DEGs (1948) were downregulated, suggesting that the exosomes suppressed stress-induced gene expression. The functional pathway analysis indicated that hASC-exosomes significantly downregulated processes related largely to translation, neuroinflammation, cellular senescence, apoptosis, and other age-associated molecular pathways. A set of genes involved in the inflammatory response and regulated by hASC-exosomes was identified. Our study provides transcriptomic evidence supporting the regulatory role of hASC-derived exosomes in attenuating the expression of inflammatory and neurodegenerative markers, positioning them as potential candidates for antiaging neurotherapeutics.