Decreased β2-adrenergic receptor-mRNA and Ioricrin-mRNA, and increased involucrin-mRNA transcripts in psoriatic epidermis: analysis by reverse transcription-polymerase chain reaction

Abstract

Psoriatic hyperproliferative epidermis is characterized by a decreased beta 2-adrenergic adenylate cyclase response as well as by altered differentiation markers that include decreased loricrin and increased involucrin. Using a quantitative reverse transcription-polymerase chain reaction, we analysed the expression of beta 2-adrenergic receptor-mRNA, loricrin-mRNA, and involucrin-mRNA in the epidermis of five patients with psoriasis vulgaris. The mRNAs of the beta 2-adrenergic receptor and loricrin in the involved epidermis were significantly decreased, by 0.35-fold (P < 0.01) and 0.55-fold (P < 0.05) respectively, compared with uninvolved epidermis. In contrast, the involucrin mRNA expression of the involved epidermis was significantly increased, by 3.77-fold (P < 0.01). No significant difference in beta-actin mRNA transcripts was detected between the involved and the uninvolved epidermis. These results indicate that the altered expression of the beta 2-adrenergic receptor, loricrin, and involucrin, in the psoriatic involved epidermis, is associated with different amounts of each mRNA transcripts.

Beta Adrenergic Receptors in Keratinocytes

“…This reduced response is likely a function of decreased expression of receptors on keratinocytes from involved psoriatic epidermis, as has been demonstrated by direct binding studies [72]. Consistent with these finding is the more recent report of decrease expression of beta 2 adrenergic receptor mRNA in involved psoriatic epidermis shown by RT-PCR [73]. Together, these findings suggest that the downregulation of the number of beta adrenergic receptors, rather than an inherent defect in the receptor itself, is the mechanism that is responsible for the reduced beta-adrenergic responsiveness seen in psoriatic epidermis.…”

Introduction

“…Catecholamine-β2 adrenergic system has been implicated in the pathogenesis of atopic dermatitis, psoriasis and vitiligo (Sivamani et al, 2007). Expression of β2 receptors is increased in vitiligo and decreased in psoriasis (Schallreuter et al, 1993, Takahashi et al, 1996). In vitiligo, there is an overproduction of 6-BH4 leading to a dysregulation of catecholamine biosynthesis with increased plasma and epidermal norepinephrine levels.…”

Roxithromycin suppresses involucrin expression by modulation of activator protein-1 and nuclear factor-κB activities of keratinocytes

“…Amplification of human involucrin gene was performed using specific oligonucleotides [23]. Amplification of GAPDH as housekeeping gene standard was performed as previously described [24].…”