Induction of keratinocyte proliferation and lymphocytic infiltration by in vivo introduction of the IL-6 gene into keratinocytes and possibility of keratinocyte gene therapy for inflammatory skin diseases using IL-6 mutant genes.
To understand biological function of IL-6 in the skin in vivo, we constructed a vector that strongly expressed human IL-6 in keratinocytes and introduced it into rat keratinocytes in vivo by the naked DNA method. The overexpression of IL-6 induced macroscopic erythema and histologically evident keratinocyte proliferation and lymphocytic infiltration in the treated area of rat skin. Since previous studies using IL-6 transgenic mice have not shown skin inflammation of these mice, our result provides the first evidence that IL-6 is related to the pathogenesis of inflammatory skin diseases. ELISA suggested that a certain degree of transgenic IL-6 expression in keratinocytes was required for inducing skin inflammation. Cytokine profile in rat keratinocytes after the gene introduction was examined by reverse transcriptase-PCR assay and revealed that gene expression of rat IL-1alpha and TNF-alpha showed no marked change until 24 h, whereas that of rat IL-6 and TGF-alpha increased with time. We then introduced and expressed the IL-6 mutant genes, which were designed to behave as IL-6Ralpha antagonists, and found that their ability to induce erythema was lower than that of the wild-type gene. Furthermore, preintroduction of some mutant genes delayed the erythema induced by postintroduction of the wild-type IL-6 gene, suggesting that the mutant forms of IL-6 prevent wild-type IL-6 from binding to IL-6Ralpha. This result indicates that keratinocyte gene therapy may be possible for inflammatory skin diseases using IL-6 mutant genes.
Sawamura
D
D
Department of Dermatology, Hirosaki University School of Medicine, Japan. smartdai@cc.hirosaki-u.ac.jp
Meng
X
X
Ina
S
S
Sato
M
M
Tamai
K
K
Hanada
K
K
Hashimoto
I
I
D000818:Animals; D002455:Cell Division; D002465:Cell Movement / Q000235:genetics / Q000276:immunology*; D016207:Cytokines / Q000235:genetics; D018014:Gene Transfer Techniques; D015316:Genetic Therapy / Q000379:methods*; D006801:Humans; D007150:Immunohistochemistry; D007249:Inflammation / Q000235:genetics / Q000276:immunology / Q000628:therapy; D015850:Interleukin-6 / Q000096:biosynthesis / Q000235:genetics*; D015603:Keratinocytes / Q000378:metabolism / Q000473:pathology*; D008214:Lymphocytes / Q000473:pathology*; D016297:Mutagenesis, Site-Directed; D012333:RNA, Messenger / Q000096:biosynthesis; D051381:Rats; D012871:Skin Diseases / Q000276:immunology / Q000473:pathology / Q000628:therapy*; D019076:Transgenes / Q000276:immunology
D016207:Cytokines; D015850:Interleukin-6; D012333:RNA, Messenger