Transcriptome Analysis Reveals Norathyriol Prolongs the Lifespan via Regulating Metabolism in C. elegans

Abstract

Background: Aging and age-related diseases are closely linked to an imbalance in energy supply and demand, a condition that can potentially be mitigated through various interventions, including the use of naturally occurring molecules. Norathyriol (NL), a tetrahydroxyxanthone compound, is prevalent in mango fruit and medicinal plants. While studies have indicated that NL may influence metabolism, its effects on aging have not been extensively explored.

Methods: We conducted lifespan analysis and measured lipofuscin accumulation in C. elegans model to evaluate the effects of NL on aging. Additionally, we identified differentially expressed genes (DEGs) through comprehensive RNA-sequencing (RNA-seq) analysis and performed gene ontology (GO) and kyoto encyclopedia of genes and genomes (KEGGs) pathway analyses to elucidate the molecular mechanisms underlying NL's effects.

Results: Our study demonstrated that NL at 50 μM extends the lifespan by 15.9% and reduces lipofuscin accumulation in C. elegans without impacting their feeding capabilities. A total of 928 DEGs were identified in NL-treated worms. The analysis of DEGs indicated that NL's longevity-promoting effects might be due to its regulation of gene expression in lipid metabolism and immune response pathways. Furthermore, the insulin/insulin-like growth factor (IGF)-1 and target of rapamycin (TOR) signaling pathways were implicated in the lifespan-extending effect of NL.

Conclusions: These findings broaden the bioactivity profile of polyphenols and highlight the need for further investigation into the therapeutic potential of NL in combating age-related diseases.

Keywords: C. elegans; aging; lipid metabolism; norathyriol; transcriptome analysis.

Figure 1

NL extends lifespan and reduces lipofuscin accumulation in C. elegans. (A) Effects of NL on lifespan in C. elegans. Synchronized worms at young-adult stage were treated with 50 μM NL (** p < 0.01, log-rank (Mantel-Cox) test). (B) Effects of NL on lipofuscin accumulation in C. elegans. The scale bar shows 100 μm. ImageJ was used to quantify the fluorescence in the left panel (n = 25 for three independent experiments). Data in bar graphs are expressed as mean ± SEM. (*** p < 0.001, two-tailed Student’s t-test).

Figure 1

NL extends lifespan and reduces lipofuscin accumulation in C. elegans. (A) Effects of NL on lifespan in C. elegans. Synchronized worms at young-adult stage were treated with 50 μM NL (** p < 0.01, log-rank (Mantel-Cox) test). (B) Effects of NL on lipofuscin accumulation in C. elegans. The scale bar shows 100 μm. ImageJ was used to quantify the fluorescence in the left panel (n = 25 for three independent experiments). Data in bar graphs are expressed as mean ± SEM. (*** p < 0.001, two-tailed Student’s t-test).

Figure 2

NL has no impact on the feeding capabilities of C. elegans. Effects of NL on feeding capabilities in C. elegans. Synchronized worms at young-adult stage were treated with 50 μM NL. Data in bar graphs are expressed as mean ± SEM. (two-tailed Student’s t-test).

Figure 3

Volcano plot, heatmap, and qPCR analysis of genes altered by NL treatment in C. elegans. (A) Volcano plots showing the results of RNA-Seq; red dots represented 446 upregulated DEGs, and blue dots represented 482 down-regulated DEGs. (B) Heatmap of the genes significantly altered after NL treatment. Color correlates with the value of z-score. Z-score = (X − mean)/SD. (C) Confirmation of RNA-Seq results by qPCR with the upregulated or downregulated 13 genes exhibiting the largest fold change (R² = 0.7306).

Figure 4

Heatmap and enrichments of GO terms associated with longevity genes altered by NL treatment in C. elegans. (A) Heatmap of significantly altered longevity-related genes after NL treatment. Color correlates with the value of z-score. Z-score = (X − mean)/SD. (B) Significant GO terms of longevity-related DEGs found by enrichment analyses in 50 μM NL-treated worms.

Figure 5

Enrichments of GO terms and KEGG pathways in the transcriptomes of NL-treated worms. (A) KEGG analysis of genes significantly upregulated in NL-treated worms. (B) Significant GO terms of upregulated DEGs found by enrichment analyses in 50 μM NL-treated worms.

Figure 5

Enrichments of GO terms and KEGG pathways in the transcriptomes of NL-treated worms. (A) KEGG analysis of genes significantly upregulated in NL-treated worms. (B) Significant GO terms of upregulated DEGs found by enrichment analyses in 50 μM NL-treated worms.

Figure 6

Effects of NL on fat accumulation in C. elegans. (A) Heatmap of significantly altered lipid-related genes after NL treatment. Color correlates with the value of z-score. Z-score = (X − mean)/SD. (B) Effects of 50 μM NL on fat accumulation in C. elegans. The scale bar shows 100 μm. Quantification of the Oil red O staining data is shown in the right panel (n = 25 for three independent experiments). Data in bar graphs are expressed as mean ± SEM. (*** p < 0.001, two-tailed Student’s t-test).