Role of melanoma chondroitin sulphate proteoglycan in patterning stem cells in human interfollicular epidermis.
Human interfollicular epidermis is renewed by stem cells that are clustered in the basal layer in a patterned, non-random distribution. Stem cells can be distinguished from other keratinocytes by high expression of beta1 integrins and lack of expression of terminal differentiation markers; they divide infrequently in vivo but form actively growing colonies in culture. In a search for additional stem cell markers, we observed heterogeneous epidermal expression of melanoma chondroitin sulphate proteoglycan (MCSP). MCSP was expressed by those keratinocytes with the highest beta1 integrin levels. In interfollicular epidermis, expression was confined to non-cycling cells and, in culture, to self-renewing clones. However, fluorescence-activated cell sorting on the basis of MCSP and beta1 integrin expression gave no more enrichment for clonogenic keratinocytes than sorting for beta1 integrins alone. To interfere with endogenous MCSP, we retrovirally infected keratinocytes with a chimera of the CD8 extracellular domain and the MCSP cytoplasmic domain. CD8/MCSP did not affect keratinocyte proliferation or differentiation but the cohesiveness of keratinocytes in isolated clones or reconstituted epidermal sheets was greatly reduced. CD8/MCSP caused stem cell progeny to scatter without differentiating. CD8/MCSP did not alter keratinocyte motility but disturbed cadherin-mediated cell-cell adhesion and the cortical actin cytoskeleton, effects that could be mimicked by inhibiting Rho. We conclude that MCSP is a novel marker for epidermal stem cells that contributes to their patterned distribution by promoting stem cell clustering.
Keratinocyte Laboratory, Cancer Research UK London Research Institute, 44 Lincoln's Inn Fields, London, WC2A 3PX, UK.
James
J
Legg
Uffe B
UB
Jensen
Simon
S
Broad
Irene
I
Leigh
Fiona M
FM
Watt
D000595:Amino Acid Sequence; D000818:Animals; D015415:Biomarkers; D016827:CD8 Antigens / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D002448:Cell Adhesion / Q000502:physiology; D002454:Cell Differentiation; D002465:Cell Movement; D002478:Cells, Cultured; D011508:Chondroitin Sulfate Proteoglycans / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D003599:Cytoskeleton / Q000378:metabolism; D000078404:Epidermal Cells; D004817:Epidermis / Q000502:physiology*; D006801:Humans; D019012:Integrin beta1 / Q000378:metabolism; D015603:Keratinocytes / Q000166:cytology / Q000378:metabolism; D008565:Membrane Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D039902:Multipotent Stem Cells / Q000502:physiology*; D017434:Protein Structure, Tertiary; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D020741:rho GTP-Binding Proteins / Q000378:metabolism; D000099216:Chondroitin Sulfate Proteoglycan 4
D015415:Biomarkers; D016827:CD8 Antigens; D011508:Chondroitin Sulfate Proteoglycans; D019012:Integrin beta1; D008565:Membrane Proteins; D011993:Recombinant Fusion Proteins; D020741:rho GTP-Binding Proteins; C101390:CSPG4 protein, human; D000099216:Chondroitin Sulfate Proteoglycan 4