Maturation of epidermal Langerhans cells : increased expression of β- and γ-actin isoforms as a basis of specialized cell functions

• Published in: Experimental dermatology Vol. 8; no. 6; pp. 487 - 494
• Main Authors: ROSS, R, ROSS, X.-L, LÄNGIN, T, RESKE-KUNZ, A. B
• Format: Journal Article
• Language: English
• Published: Oxford Blackwell 01.12.1999
• Subjects: Actins - genetics; Actins - metabolism; Animals; Base Sequence; Biological and medical sciences; Cell Differentiation; Dendritic Cells - cytology; Dendritic Cells - immunology; Dendritic Cells - metabolism; Dermatology; DNA Primers - genetics; DNA, Complementary - genetics; In Vitro Techniques; Investigative techniques, diagnostic techniques (general aspects); Langerhans Cells - cytology; Langerhans Cells - immunology; Langerhans Cells - metabolism; Medical sciences; Mice; Mice, Inbred BALB C; Pathology. Cytology. Biochemistry. Spectrometry. Miscellaneous investigative techniques; Protein Isoforms - genetics; Protein Isoforms - metabolism; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger - genetics; RNA, Messenger - metabolism; Up-Regulation; Human; Ripening; Dendritic cell; Langerhans cell; Actin; Cytoskeleton; Epidermis; Skin
• ISSN: 0906-6705; 1600-0625
• DOI: 10.1111/j.1600-0625.1999.tb00307.x

Epidermal Langerhans cells (LC) represent immature dendritic cells. During in vitro culture in the presence of keratinocytes they mature into potent immunostimulatory cells for naive T cells. This process is thought to simulate in vivo maturation of LC following activation by antigen contact. Maturation of LC is accompanied by morphological alterations. Applying a differential screening procedure we isolated differentially expressed cDNAs involved in the maturation events including cDNAs of the cytoskeletal actin isoforms beta- and gamma-actin. Stronger signals with hybridization probes derived from cultured LC compared with probes derived from freshly isolated LC indicate upregulation of actin expression. Upregulated expression of actin was confirmed by RT-PCR, Western blot and immunofluorescence analysis. Staining with fluorescence-labelled phalloidin that selectively binds to polymerized F-actin, indicates an increase in F-actin levels in cultured LC. Thus our data show that maturation of LC, which involves formation of dendritic structures and movement of formerly immobile cells, is accompanied by augmented expression of actin and formation of additional actin filaments. Furthermore, actin mRNA, often used as reference to assess mRNA amounts for Northern blotting or competitive RT-PCR because of its high and ubiquitous expression, is an inappropriate standard for the analysis of LC and DC.