Localization of transglutaminase 1 mRNA in normal and psoriatic epidermis by non-radioactive in situ hybridization

Abstract

We examined the expression of the transglutaminase 1 (TGase 1) gene in frozen sections of normal and psoriatic epidermis by means of non-radioactive in situ hybridization with digoxigenin-labelled cRNA probes. TGase 1 mRNA was expressed in the granular layer of normal epidermis, regardless of ortho- or hyperkeratosis. However, in psoriatic epidermis, TGase 1 mRNA was detected in the suprabasal spinous layer, but not in the subcorneal layer. These results indicate that TGase 1 gene expression is limited to the last stage of keratinization in normal epidermis and this regulation is disturbed in psoriasis.

Epidermal differentiation characteristics of the psoriatic plaque during treatment with calcipotriol

“…The activity of TGase 1 and the number of cornified envelopes produced are also greatly enhanced [28]. Messenger RNA of involucrin and TGase 1 is localized early in the lower cell layers of the suprabasal epidermis [26]. This is in contrast to the situation found in normal skin [26].…”

“…In normal skin, staining with antibodies against TGase 1 and involucrin shows a band-like pattern in the upper part of the epidermis representing the upper stratum spinosum and the stratum granulosum [25]. In situ hybridization techniques have demonstrated involucrin and TGase 1 mRNA at the transition to the stratum granulosum as a very early event in differentiation [26]. Activity of TGase 1 has been demonstrated in vivo in mice in the transition zone (one or at most two cell layers) from the stratum granulosum to the stratum corneum [25].…”

“…In psoriatic skin, the keratinization process is disturbed. Large, clinically visible, histologically parakeratotic squames are formed in lesional skin [26]. Staining with monoclonal antibodies against involucrin and TGase 1 demonstrates far more positive cell layers, relatively as well as absolutely [27].…”

Transcription regulatory elements of the first intron control human transglutaminase type I gene expression in epidermal keratinocytes

“…In vivo, TGase 1 activity is limited to the narrow band of terminally differentiating epidermal cells in the stratum granulosum [Michel and Demarchez, 1988], while the TGM1 gene is transcriptionally and translationally active earlier, in suprabasal [Nonomura et al, 1993;Michel et al, 1992] or even in proliferating basal [Schroeder et al, 1992;Parenteau et al, 1986] cell layers. Both keratinocyte differentiation and TGM1 gene expression appear to be controlled by the affect of opposing Ca 2ϩ and retinoic acid (RA) concentration gradients, existing in the native epidermis [Menon and Elias, 1991;Fisher and Voorhees, 1996;Vicanova et al, 1998], on intracellular levels.…”

“…The temporal and spatial patterns of RNA and the protein cellular and subcellular distribution vary during development [Polakowska et al, 1994;Nonomura et al, 1993], between keratinocyte growth conditions [Saunders et al, 1993;Steinert et al, 1996;Yada et al, 1993], and between keratinizing epithelia of different sites of origin and of different species [Schroeder et al, 1992;Michel et al, 1992], indicating that regulatory mechanisms involved in expression of the active TGase 1 are complex and may operate at all levels of genetic control.…”