Hemopoietic stem cell inhibitor (SCI/MIP-1 alpha) also inhibits clonogenic epidermal keratinocyte proliferation.
The maintenance and regulation of continuously renewing tissues is ultimately controlled at the level of stem-cell proliferation. We have recently identified a reversible inhibitor of hemopoietic stem-cell proliferation (stem-cell inhibitor [SCI]), which is identical to the macrophage inflammatory protein, MIP-1 alpha, a 69-amino-acid heparin-binding cytokine. To test the cell/tissue specificity of the inhibition of proliferation by SCI/MIP-1 alpha, we have investigated its activity on epidermal keratinocytes, the principal cell type of another continuously renewing tissue. Here we show that SCI/MIP-1 alpha inhibits the proliferation of epidermal keratinocytes in vitro and that the MIP-1 alpha mRNA is present in epidermal Langerhans cells but not in keratinocytes. This suggests an important growth regulatory function for SCI/MIP-1 alpha in keratopoiesis, as well as hemopoiesis, and may also indicate a novel role for the epidermal Langerhans cell. As SCI/MIP-1 alpha can inhibit the proliferation of embryologically distinct precursor cells, this raises the possibility that it may also function in a number of other tissues.
Parkinson
E K
EK
CRC Beatson Laboratories, Beatson Institute for Cancer Research, Bearsden, Glasgow, U.K.
Graham
G J
GJ
Daubersies
P
P
Burns
J E
JE
Heufler
C
C
Plumb
M
M
Schuler
G
G
Pragnell
I B
IB
D000818:Animals; D015152:Blotting, Northern; D002455:Cell Division / Q000187:drug effects; D054407:Chemokine CCL4; D016207:Cytokines / Q000032:analysis / Q000235:genetics / Q000494:pharmacology*; D006801:Humans; D015603:Keratinocytes / Q000166:cytology*; D007801:Langerhans Cells / Q000737:chemistry; D019402:Macrophage Inflammatory Proteins; D051379:Mice; D015846:Monokines / Q000032:analysis / Q000235:genetics / Q000494:pharmacology*; D012333:RNA, Messenger / Q000032:analysis
D054407:Chemokine CCL4; D016207:Cytokines; D019402:Macrophage Inflammatory Proteins; D015846:Monokines; D012333:RNA, Messenger