Fig 1: Keratinocyte Differentiation Trajectories(A) Diagram showing the layers of the epidermis and morphologic changes associated with keratinocyte differentiation.(B) t-SNE plot showing differentiation trajectory of keratinocytes from normal skin from basal cells (yellow) through differentiating cells (aqua) and terminal keratinocytes (purple).(C) (Top, left) t-SNE plot of normal keratinocytes colored by KRT14 expression. Shown at the top right is KRT14 staining from the human protein atlas (Uhlén et al., 2015). Shown on the bottom left is a t-SNE plot of normal keratinocytes colored by FLG expression. Shown on the bottom right is FLG staining from the human protein atlas (Uhlén et al., 2015). Scale bars, 50 µm.(D) Diffusion map of 10,777 keratinocytes colored by inflammatory skin condition. Axes correspond to diffusion components 1, 2, and 3.(E) Diffusion map of keratinocytes colored by signatures of hair-follicle-specific gene expression (Joost et al., 2016) (Left: outer bulge, inner bulge, and upper hair follicle) and genes that distinguish basal (COL17A1), normal (KRT77), and inflamed (S100A9) keratinocytes.(F) Volcano plot of genes differentially expressed between psoriatic and normal keratinocytes. Log10-fold change values are shown on the x axis and -log10 adjusted p values are shown on the y axis.(G) Heatmap showing gene-specific Pearson correlation values between diffusion pseudotime and gene expression for two normal skin biopsies and five psoriatic biopsies.(H) (Top) Immunofluorescence staining in normal (above) and psoriatic (below) for FOSL, IL36G, TNFAIP3, and APOBEC3. All images stained for nuclei (DAPI) and gene of interest (red fluorescence). Scale bar, 100 µm.(I). Immunofluorescence staining for IL-17R expression (green) in normal (left), uninvolved (middle), and psoriatic skin (right). Scale bar, 100 µm.