Single-cell gene expression profiling reveals functional heterogeneity of undifferentiated human epidermal cells

TY - JOUR

T1 - Single-cell gene expression profiling reveals functional heterogeneity of undifferentiated human epidermal cells

AU - Tan, David W M

AU - Jensen, Kim B

AU - Trotter, Matthew W B

AU - Connelly, John T

AU - Broad, Simon

AU - Watt, Fiona M

PY - 2013/4/1

Y1 - 2013/4/1

N2 - SUMMARY Human epidermal stem cells express high levels of β1 integrins, delta-like 1 (DLL1) and the EGFR antagonist LRIG1. However, there is cell-to-cell variation in the relative abundance of DLL1 and LRIG1 mRNA transcripts. Single-cell global gene expression profiling showed that undifferentiated cells fell into two clusters delineated by expression of DLL1 and its binding partner syntenin. The DLL1+ cluster had elevated expression of genes associated with endocytosis, integrin-mediated adhesion and receptor tyrosine kinase signaling. Differentially expressed genes were not independently regulated, as overexpression of DLL1 alone or together with LRIG1 led to the upregulation of other genes in the DLL1+ cluster. Overexpression of DLL1 and LRIG1 resulted in enhanced extracellular matrix adhesion and increased caveolin-dependent EGFR endocytosis. Further characterisation of CD46, one of the genes upregulated in the DLL1+ cluster, revealed it to be a novel cell surface marker of human epidermal stem cells. Cells with high endogenous levels of CD46 expressed high levels of β1 integrin and DLL1 and were highly adhesive and clonogenic. Knockdown of CD46 decreased proliferative potential and β1 integrin-mediated adhesion. Thus, the previously unknown heterogeneity revealed by our studies results in differences in the interaction of undifferentiated basal keratinocytes with their environment.

AB - SUMMARY Human epidermal stem cells express high levels of β1 integrins, delta-like 1 (DLL1) and the EGFR antagonist LRIG1. However, there is cell-to-cell variation in the relative abundance of DLL1 and LRIG1 mRNA transcripts. Single-cell global gene expression profiling showed that undifferentiated cells fell into two clusters delineated by expression of DLL1 and its binding partner syntenin. The DLL1+ cluster had elevated expression of genes associated with endocytosis, integrin-mediated adhesion and receptor tyrosine kinase signaling. Differentially expressed genes were not independently regulated, as overexpression of DLL1 alone or together with LRIG1 led to the upregulation of other genes in the DLL1+ cluster. Overexpression of DLL1 and LRIG1 resulted in enhanced extracellular matrix adhesion and increased caveolin-dependent EGFR endocytosis. Further characterisation of CD46, one of the genes upregulated in the DLL1+ cluster, revealed it to be a novel cell surface marker of human epidermal stem cells. Cells with high endogenous levels of CD46 expressed high levels of β1 integrin and DLL1 and were highly adhesive and clonogenic. Knockdown of CD46 decreased proliferative potential and β1 integrin-mediated adhesion. Thus, the previously unknown heterogeneity revealed by our studies results in differences in the interaction of undifferentiated basal keratinocytes with their environment.

KW - Biological Markers

KW - Cell Differentiation

KW - Cells, Cultured

KW - Epidermis

KW - Epithelial Cells

KW - Gene Expression Profiling

KW - Genetic Heterogeneity

KW - Humans

KW - Keratinocytes

KW - Microarray Analysis

KW - Models, Biological

KW - Polymerase Chain Reaction

KW - Single-Cell Analysis

KW - Stem Cells

KW - Validation Studies as Topic

U2 - 10.1242/dev.087551

DO - 10.1242/dev.087551

M3 - Journal article

C2 - 23482486

SN - 0950-1991

VL - 140

SP - 1433

EP - 1444

JO - Development

JF - Development

IS - 7

ER -