Abstract
Three desmoglein (Dsg) isoforms are expressed in a differentiation- specific fashion in the epidermis, with Dsg2 being basal, Dsg3 (pemphigus vulgaris antigen) basal and spinous, and Dsg1 (pemphigus foliaceus antigen) predominately granular. To better understand the mechanism(s) regulating Dsg isoform expression, we examined the expression pattern of Dsg1, Dsg2, and Dsg3 in normal human epidermal keratinocytes (NHEKs), the immortalized, nontumorigenic HaCaT cell line, and several squamous cell carcinoma cell lines (SCC-9, SCC-12F, SCC-13, and SCC-25). In all cells, the accumulation of high Dsg protein levels required calcium and was not observed in low calcium (0.050.07 mM) media. NHEKs expressed Dsg1 in all media tested, consistent with their normal differentiation capacity. HaCaT and SCC-25 also expressed Dsg1; however, the presence of serum in the media dramatically decreased Dsg1 protein levels. Serum also inhibited Dsg1 mRNA levels in HaCaT cells. Dsg1 was not detected in extracts from SCC-9, SCC-12F, and SCC-13 under any conditions. Since activation of protein kinase C (PKC) is involved in keratinocyte differentiation, we evaluated the effects of PKC down-regulation on Dsg isoform expression. Long-term treatment with either the phorbol ester 12-O-tetradecanoylphorbol-13-acetate (TPA) or bryostatin I inhibited levels of Dsg1 and Dsg3, but not Dsg2 in NHEKs and HaCaT cells. Chronic TPA also decreased Dsg1 and Dsg3 mRNA levels in NHEKs, further supporting a role for PKC activation in the expression of the suprabasal Dsg1 and Dsg3. These results identify several regulatory mechanisms by which the differentiation- specific pattern of desmosomal cadherins is established in the epidermis.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 50-59 |
| Number of pages | 10 |
| Journal | Experimental Cell Research |
| Volume | 239 |
| Issue number | 1 |
| DOIs | |
| State | Published - Feb 25 1998 |
Funding
We thank Dr. Edel O'Toole from the Department of Dermatology, Northwestern University, and members of Dr. Laimonis Laimins' laboratory in the Department of Microbiology and Immunology, Northwestern University, for help with primary keratinocyte culture techniques. We also thank Dr. Ricardo Monzon in the Department of Pharmacology at Northwestern University for providing delipidized fetal bovine serum, Paul A. Kowalczyk for providing foreskins for primary keratinocyte cultures, and David Suhy and Dr. Thomas O'Halloran in the Department of Chemistry at Northwestern University for quantitating calcium levels in media. In addition, we thank Laura A. Nilles for excellent technical assistance and Helena L. Palka for critically reading this manuscript. We are grateful to Drs. John Stanley, Werner Franke, Tung-Tien Sun, and Pierre Coulombe for generously providing desmoglein and keratin antibodies and to Dr. Norbert Fusenig at the German Cancer Research Center, Heidelberg, Germany, for providing HaCaT cells. A preliminary report of this work was presented at the 1997 Society for Investigative Dermatology Annual Meeting. This work was supported by NIH Grant RO1AR41836 and Grant PO1DE12328. Dr. Kathleen J. Green is an American Cancer Society Faculty Research Awardee, Dr. Mitchell F. Denning was supported in part by NIH Postdoctoral Training Grant AR07593, and Suzanne M. Norvell was supported by NIH Molecular Toxicology Training Grant 1T32ES07284.
ASJC Scopus subject areas
- Cell Biology
