Differential Expression of GRO-α and IL-8 mRNA Psoriasis: A Model for Neutrophil Migration and Accumulation In Vivo

Abstract

Dense focal accumulation of neutrophils in the upper epidermis is a hallmark of psoriasis. Because the signals for neutrophil diapedesis and migration in vivo are not fully understood, psoriatic lesions with pronounced migration of neutrophils may serve as an important model for studying neutrophil chemotaxis. In this study, we present evidence for differential expression of the neutrophil chemotactic cytokines growth-related oncogene alpha, interleukin-8, and ENA-78 (epithelial cell derived and neutrophil-activating properties, 78 amino acids) in psoriatic lesions. In situ hybridization and immunohistochemistry of serial sections were employed to identify and microanatomically localize the cells producing these chemokines. High levels of focal interleukin-8 message were found to be expressed in the upper epidermis by keratinocytes and, most importantly, neutrophils themselves. Growth-related oncogene alpha transcripts were detected in clusters of keratinocytes of the upper epidermis at the same sites where interleukin-8 mRNA was abundant. In contrast to interleukin-8, growth-related oncogene alpha was also detected in the papillary dermis produced by vessel-associated cells. Sites of interleukin-8 and growth-related oncogene alpha mRNA expression were associated with infiltration of neutrophils. Interestingly, mRNA expression of the highly homologous chemokine ENA-78 was quiescent. In conclusion, our data indicate that growth-related oncogene alpha is an important chemoattractant for neutrophil diapedesis in vivo, whereas further migration of neutrophils and formation of micropustules appears to be influenced by the cooperative action of both growth-related oncogene alpha and interleukin-8.

Differential and Sequential Expression of Multiple Chemokines during Elicitation of Allergic Contact Hypersensitivity

“…Furthermore, diapedesis and migration from the dermal into the epidermal compartment may be regulated by a sequential and spatial different set of chemokines as recently demonstrated for other inflammatory conditions of the skin. 15,16 In particular, the elegant in vitro studies of neutrophil locomotion through complex fields of overlapping chemoattractant gradients by Foxman and colleagues 17 have strengthened the still unproven concept that the spatial guidance of cells in tissue may not be a linear event of a single chemokine gradient but rather requires a complex network of sequential and combinatorial chemoattractant effects. To prove this concept of effector cell recruitment and positioning in vivo we applied in situ hybridization to study a large panel of radiolabeled chemokine anti-sense probes on serial tissue sections of biopsies obtained at various time intervals after allergen exposure to the skin of sensitized volunteers.…”

“…In vitro transcription of sense and anti-sense probes was performed as described earlier. 15,16 Radiolabeled probes were obtained by incubation of linearized plasmids with either T7, T3, or SP6 RNA polymerases and ATP, GTP, CTP (all obtained from Roche Molecular Biochemicals, Mannheim, Germany) and 35 S-UTP (Amersham Pharmacia Biotech) as substrates. The original template cDNA was eliminated by DNase treatment and protein components were removed by several phenol extraction steps.…”

“…15,16 Cryostat sections were fixed in 4% paraformaldehyde and treated with 1 g/ml proteinase K (Roche Molecular Biochemicals). Sections were acetylated with acetic anhydride in 0.1 mol/L triethanolamine (pH 8.0, 10 minutes), dehydrated in alcohol, and air-dried.…”

IL-4 Enhances Keratinocyte Expression of CXCR3 Agonistic Chemokines

“…Keratinocytes are the outermost component of the skin, and they can be activated by diverse factors to produce chemokines important for the recruitment and activation of immune cells, and the formation of the T cell-rich infiltrate that characterizes chronic inflammatory skin diseases such as allergic contact dermatitis (ACD), psoriasis, and atopic dermatitis (7)(8)(9). In the skin environment, keratinocytes are considered the major source of IP-10 compared with endothelial cells, monocytes, and fibroblasts (10).…”

Interleukin-8 Overexpression Is Present in Pyoderma Gangrenosum Ulcers and Leads to Ulcer Formation in Human Skin Xenografts

“…In contrast, high levels of IL-8 have been detected during acute inflammatory reactions (Garner et al, 1994;Ono et al, 1995;Strickland et al, 1997;Zweiman et al, 1997); in chronic skin diseases such as psoriasis vulgaris (Gearing et al, 1990;Nickoloff et al, 1991;Anttila et al, 1992;Schrö der et al, 1992;Schulz et al, 1993;Gillitzer et al, 1991;Gillitzer et al, 1996), palmoplantar pustulosis (Anttila et al, 1992), and bullous pemphigoid (Schmidt, 1996); and in nonmelanoma and melanoma skin tumors (Hansen et al, 1991;Ciotti et al, 1995;Bornscheuer et al, 1996). However, the role of IL-8 in the pathogenesis of skin diseases has been difficult to elucidate because of the abundance of other cytokines that can induce IL-8 expression.…”