Fig. 1

HNRNPK is necessary to sustain epidermal progenitor cell function. a Epidermal progenitor cells were knocked down with control (CTLi) or HNRNPK (HNRNPKi) siRNAs and the remaining HNRNPK mRNA levels were measured by RT-QPCR. QPCR results were normalized to L32 levels. n = 3 independent experiments b CTLi and HNRNPKi cells were seeded at 100,000 and counted 4 days later. c RT-QPCR for epidermal differentiation gene expression in CTLi and HNRNPKi cells. QPCR results were normalized to L32 levels. n = 4. d Human epidermis was regenerated using three-dimensional organotypic cultures with CTLi or HNRNPKi cells. Expression of differentiation markers (K1, K10, and FLG) and proliferation index (Ki67) were characterized by immunostaining at day 3. White scale bar = 20 μm, n = 2. e RT-QPCR for epidermal differentiation gene expression in CTLi and HNRNPKi regenerated human epidermis. n = 2. f The in-vivo progenitor cell competition assay was performed by mixing an equal number of GFP or dsRED labeled CTLi or HNRNPKi cells and used to regenerate human epidermis on immune-compromised mice. Skin grafts were harvested at days 3 and 18 post-grafting. shRNA knockdown of HNRNPK in-vivo was mediated through retroviral gene transfer to obtain stable gene suppression. The dashed white lines denote the basement membrane zone. White arrows mark remaining HNRNPKi cells in the epidermis. n = 3 animals grafted per timepoint per group. White scale bar = 20 μm. g Quantitation of the percentage of GFP and dsRED cells remaining in the epidermis at days 3 and 18 using ImageJ. h RNA-Seq analysis of CTLi and HNRNPKi cells. Cells were cultured for 7 days and subjected to RNA-Seq. Heatmap of the genes that change upon HNRNPK depletion are shown in red (induced) and blue (downregulated) on a log2 scale. RNA-Seq was performed in biological replicates. i Top 6 gene ontology terms for the genes upregulated in HNRNPKi cells using Enrichr. j Gene ontology terms for the downregulated genes in HNRNPKi cells using Enrichr. n = 3 independent experiments performed in Fig. 1 unless otherwise indicated. Mean values are shown with error bars = SD. *p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001: a, b, c, e, g: t-test (two sided)