Abstract
UV irradiation is a major insult to the skin. We have shown previously that exogenous vitamin C (ascorbate) accmmulates in HaCaT keratinocytes, thus conferring the ability to prevent radical formation and cell death elicited by UV-B. Here, we have investigated the potential mechanisms accounting for the cytoprotective effects exerted by this antioxidant. Using a cDNA microarray hybridization, we identified several genes whose expression was up-regulated by ascorbate. We focused on the fra-1 gene, a member of the Fos family of transcription factors that down-regulates activator protein-1 (AP-1) target genes. Both in HaCaT and in normal human epidermal keratinocytes, we found Fra-1 mRNA induction as early as 2 h after ascorbate loading. Electrophoretic mobility-shift assay and antibody supershift analysis revealed that ascorbate modulates AP-1 DNA-binding activity and that Fra-1 is in AP-1 complexes in treated cells. Furthermore, transient-transfection studies, using an AP-1 reporter construct, showed that ascorbate was able to inhibit both basal and UV-B-induced AP-1-dependent transcription. Ascorbate also modulates UV-B-induced AP-1 activity by preventing the phosphorylation and activation of the upstream c-Jun N-terminal kinase (JNK), thus inhibiting phosphorylation of the endogenous c-Jun protein. These data suggest that ascorbate mediates cellular responses aimed at counteracting UV-mediated cell damage and cell death by interfering at multiple levels with the activity of the JNK/AP-1 pathway and modulating the expression of AP-1-regulated genes.
| Original language | English |
|---|---|
| Pages (from-to) | 77-85 |
| Number of pages | 9 |
| Journal | Biochemical Journal |
| Volume | 356 |
| Issue number | 1 |
| DOIs | |
| Publication status | Published - May 15 2001 |
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Keywords
- Fra-1
- JNK
- Vitamin C
ASJC Scopus subject areas
- Biochemistry
Cite this
Induction of gene expression via activator protein-1 in the ascorbate protection against UV-induced damage. / Catani, M. Valeria; Rossi, Antonello; Costanzo, Antonio; Sabatini, Stefania; Levrero, Massimo; Melino, Gerry; Avigliano, Luciana.
In: Biochemical Journal, Vol. 356, No. 1, 15.05.2001, p. 77-85.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Induction of gene expression via activator protein-1 in the ascorbate protection against UV-induced damage
AU - Catani, M. Valeria
AU - Rossi, Antonello
AU - Costanzo, Antonio
AU - Sabatini, Stefania
AU - Levrero, Massimo
AU - Melino, Gerry
AU - Avigliano, Luciana
PY - 2001/5/15
Y1 - 2001/5/15
N2 - UV irradiation is a major insult to the skin. We have shown previously that exogenous vitamin C (ascorbate) accmmulates in HaCaT keratinocytes, thus conferring the ability to prevent radical formation and cell death elicited by UV-B. Here, we have investigated the potential mechanisms accounting for the cytoprotective effects exerted by this antioxidant. Using a cDNA microarray hybridization, we identified several genes whose expression was up-regulated by ascorbate. We focused on the fra-1 gene, a member of the Fos family of transcription factors that down-regulates activator protein-1 (AP-1) target genes. Both in HaCaT and in normal human epidermal keratinocytes, we found Fra-1 mRNA induction as early as 2 h after ascorbate loading. Electrophoretic mobility-shift assay and antibody supershift analysis revealed that ascorbate modulates AP-1 DNA-binding activity and that Fra-1 is in AP-1 complexes in treated cells. Furthermore, transient-transfection studies, using an AP-1 reporter construct, showed that ascorbate was able to inhibit both basal and UV-B-induced AP-1-dependent transcription. Ascorbate also modulates UV-B-induced AP-1 activity by preventing the phosphorylation and activation of the upstream c-Jun N-terminal kinase (JNK), thus inhibiting phosphorylation of the endogenous c-Jun protein. These data suggest that ascorbate mediates cellular responses aimed at counteracting UV-mediated cell damage and cell death by interfering at multiple levels with the activity of the JNK/AP-1 pathway and modulating the expression of AP-1-regulated genes.
AB - UV irradiation is a major insult to the skin. We have shown previously that exogenous vitamin C (ascorbate) accmmulates in HaCaT keratinocytes, thus conferring the ability to prevent radical formation and cell death elicited by UV-B. Here, we have investigated the potential mechanisms accounting for the cytoprotective effects exerted by this antioxidant. Using a cDNA microarray hybridization, we identified several genes whose expression was up-regulated by ascorbate. We focused on the fra-1 gene, a member of the Fos family of transcription factors that down-regulates activator protein-1 (AP-1) target genes. Both in HaCaT and in normal human epidermal keratinocytes, we found Fra-1 mRNA induction as early as 2 h after ascorbate loading. Electrophoretic mobility-shift assay and antibody supershift analysis revealed that ascorbate modulates AP-1 DNA-binding activity and that Fra-1 is in AP-1 complexes in treated cells. Furthermore, transient-transfection studies, using an AP-1 reporter construct, showed that ascorbate was able to inhibit both basal and UV-B-induced AP-1-dependent transcription. Ascorbate also modulates UV-B-induced AP-1 activity by preventing the phosphorylation and activation of the upstream c-Jun N-terminal kinase (JNK), thus inhibiting phosphorylation of the endogenous c-Jun protein. These data suggest that ascorbate mediates cellular responses aimed at counteracting UV-mediated cell damage and cell death by interfering at multiple levels with the activity of the JNK/AP-1 pathway and modulating the expression of AP-1-regulated genes.
KW - Fra-1
KW - JNK
KW - Vitamin C
UR - http://www.scopus.com/inward/record.url?scp=0035874482&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0035874482&partnerID=8YFLogxK
U2 - 10.1042/0264-6021:3560077
DO - 10.1042/0264-6021:3560077
M3 - Article
C2 - 11336638
AN - SCOPUS:0035874482
VL - 356
SP - 77
EP - 85
JO - Biochemical Journal
JF - Biochemical Journal
SN - 0264-6021
IS - 1
ER -