Figure 4.

Transcriptional similarities between clinical sarcopenia muscle and engineered skeletal muscle in microgravity

(A) Principal-component analysis of the transcriptome in healthy vs. sarcopenia clinical samples from both sexes.

(B) Volcano plot shows differentially expressed genes in sarcopenia, compared to normal conditions (p < 0.05, log2 FC > 1.0). Genes involved in DNA damage response, extracellular matrix organization, VEGFA-VEGFR2 signaling pathway, and Wnt signaling are labeled. Genes showing statistically significant expression (FDR 25%) are indicated in red.

(C) Heatmap shows the genes involved in Wnt signaling, rhabdomyosarcoma, DNA damage response, extracellular matrix organization, and VEGFA-VEGFR2 signaling.

(D–F) Enrichment plots for custom gene set enrichment analysis (GSEA). The plots report positive enrichment of Old_MuSC_UP gene set (D) and negative enrichment of Sarcopenia_UP and Sarcopenia-DOWN gene sets (E–F) in microgravity, compared to gravity samples. The enrichment plot shows the gene set names (top) and the running enrichment score. The red curve indicates positive enrichment, whereas the blue curve indicates negative enrichment scores. Black bars indicate the positions of the gene set on the rank-ordered list in GSEA, and the signal-to-noise metrics are shown at the bottom.