Expression and function of nerve growth factor and nerve growth factor receptor on cultured keratinocytes.
Keratinocytes, a key cellular component both for homeostasis and pathophysiologic processes of the skin, secrete a number of cytokines and are stimulated by several growth factors. Nerve growth factor (NGF) is synthesized in the skin and basal keratinocytes express the low-affinity nerve growth factor receptor (NGF-R). We present evidence that normal human keratinocytes in culture express the low- and the high-affinity NGF-R both at the mRNA level, as determined by reverse-transcription polymerase chain reaction and at the protein level, as shown by cytofluorimetric analysis. NGF significantly stimulates the proliferation of normal human keratinocytes in culture in a dose-dependent manner. This effect can be prevented by the addition of both an anti-NGF neutralizing antibody and a high-affinity NGF-R (trk) specific inhibitor, the natural alkaloid K252a. By contrast, keratinocyte proliferation is not inhibited by an anti-low-affinity NGF-R monoclonal antibody, thus suggesting that NGF effect on human keratinocytes is mediated by the high-affinity NGF-R. Moreover, NGF mRNA is expressed in normal human keratinocytes and NGF is secreted by keratinocytes in increasing amounts during growth, as detected by enzyme-linked immunosorbent assay. These results suggest that NGF could act as a cytokine in human skin and take part in disorders of keratinocyte proliferation.
Department of Hematology, University of Modena, Italy.
C
C
Pincelli
C
C
Sevignani
R
R
Manfredini
A
A
Grande
F
F
Fantini
L
L
Bracci-Laudiero
L
L
Aloe
S
S
Ferrari
A
A
Cossarizza
A
A
Giannetti
D000911:Antibodies, Monoclonal / Q000276:immunology / Q000494:pharmacology; D001483:Base Sequence; D002227:Carbazoles / Q000494:pharmacology; D002455:Cell Division / Q000187:drug effects; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D004797:Enzyme-Linked Immunosorbent Assay; D005434:Flow Cytometry; D005455:Fluorescent Antibody Technique; D015870:Gene Expression; D006801:Humans; D026121:Indole Alkaloids; D015603:Keratinocytes / Q000737:chemistry / Q000166:cytology* / Q000648:ultrastructure; D008969:Molecular Sequence Data; D009414:Nerve Growth Factors / Q000032:analysis / Q000494:pharmacology / Q000502:physiology*; D016133:Polymerase Chain Reaction; D011493:Protein Kinase C / Q000037:antagonists & inhibitors; D012333:RNA, Messenger / Q000032:analysis / Q000235:genetics; D017475:Receptors, Nerve Growth Factor / Q000032:analysis / Q000235:genetics / Q000502:physiology*
D000911:Antibodies, Monoclonal; D002227:Carbazoles; D026121:Indole Alkaloids; D009414:Nerve Growth Factors; D012333:RNA, Messenger; D017475:Receptors, Nerve Growth Factor; C049985:staurosporine aglycone; D011493:Protein Kinase C