Extended Data Fig. 9. Age-associated changes in the cell types within muscle microenvironment.
a, UMAP plots highlighting expression of terminal Schwann cell markers in non-myelinating Schwann cell cluster. b, Scanned whole sections showing co-IF of CD3 and Laminin on fresh-frozen human young vs. aged skeletal muscles. Staining was performed on 6 young and 4 aged donors. Scale bar: 500 µm. c, An exemplary field of view showing 15-plex RareCyte protein staining on aged FFPE skeletal muscle section. Staining is shown for 5 channels at a time together with Hoechst nuclei staining as well as for each channel separately highlighting various cell types and states. Antibodies used and the corresponding cell types they recognize are provided in Supplementary Table 9. Scale bar: 50 µm. d, RareCyte staining of CD31+ endothelial cells (left) and bar plots (right) illustrating number of CD31+ cells/field in young (10 fields) vs. aged (10 fields) donors. Scale bar: 50 µm. p value: unpaired two-tailed t-test. ***, p < 0.001. Data were presented as mean ± s.e.m. with individual data points shown. e, Putative cell-cell interactions in the aged skeletal muscle mediated via CCL3, CCL4 and CXCL8 chemokines produced by microenvironment cells. Emitter (leftmost) and receiver (rightmost) cell types are marked with circles, which are coloured according to a broad cell type group; ligands and receptors are marked with square nodes. Solid edges connect cell types and ligands, or receptors, which they express; thickness of the line is proportional to the mean expression level of the gene in each cell type. Dotted edges connect putative receptors and their ligands.