Hyun-Joo Cho

Insulin-like Growth Factor–Binding Protein Contributes to the Proliferation of Less Proliferative Cells in Forming Skin Equivalents

In this study, the effects and the mediating factors of dermal cells on the epidermal regenerative ability were investigated. Human epidermal cells were separated into rapidly adhering (RA) cells and slowly adhering (SA) cells and used for culturing skin equivalents (SEs). For dermal part, normal human fibroblasts, dermal sheath cells (DSCs), and dermal papilla cells were used. SEs produced using SA cells and DSCs showed a thicker epidermis and higher expressions of alpha(6)- and beta1-integrin than SEs using SA cells and normal fibroblasts showed. We hypothesized that DSCs may secrete specific cytokines that can influence the regenerative potential of epidermal cells, and compared cytokine secretion by DSCs and normal human fibroblasts. Using RayBio human cytokine antibody array C (series 1000), 120 cytokines were tested. Results showed that DSCs produced a much greater amount of insulin-like growth factor-binding protein (IGFBP-2), angiogenin, and BMP-6 than normal human fibroblasts produced. On the basis of the cytokine antibody array, we next investigated whether IGFBP-2, angiogenin, or BMP-6 has effects on SEs reconstruction. The addition of IGFBP-2 induced a thicker and more mature epidermis and higher expressions of alpha(6)- and beta1-integrin, whereas BMP-6 exhibited little effect. Thus, the SEs with IGFBP-2 showed almost the same morphology of the SEs using DSCs. Further, p63, a putative keratinocyte stem cell marker, was more frequently observed in the basal layer of SE with IGFBP-2. In conclusion, IGFBP-2 is a major factor from DSCs that affects epidermal regenerative capacity of skin and may play an important role for stemness maintenance in human epidermal keratinocytes.

Epstein-Barr virus-associated lymphoproliferative eruption with progression to large granular lymphocytic leukaemia.

A 12‐year‐old Korean girl gave a 9‐year history of recurrent necrotizing papules and vesicles on the face, scalp and extremities. Skin biopsy specimens showed an atypical lymphoreticular infiltrate with vasculitis in the dermis and subcutis. In situ hybridization demonstrated latent infection by Epstein‐Barr virus (EBV) of the lymphoid cells in the dermis. The disease was diagnosed as an EBV‐associated lymphoproliferative skin eruption presenting as recurrent necrotic papulovesicles. The patient subsequently developed large granular lymphocytic leukaemia of natural killer cell origin. Our observations suggest that a patient with an EBV‐associated lymphoproliferative skin eruption presenting with recurrent necrotic papulovesicles might progress to develop leukaemia as well as lymphoma.

Differential expression of p63 isoforms in normal skin and hyperproliferative conditions

Background:u2002 The p63 is regarded as a potential stem cell marker.

Spatholobus suberectus Dunn. constituents inhibit sortase A and Staphylococcus aureus cell clumping to fibrinogen

Sortases are a family of Gram-positive transpeptidases responsible for anchoring surface protein virulence factors to the peptidoglycan cell wall layer. In Staphylococcus aureus (S. aureus), deletion of sortase isoform results in a significant reduction in virulence and infection potential. Twenty flavonoids were isolated from the stem of the folk medicinal plant Spatholobus suberectus Dunn. These compounds were tested against S. aureus-derived sortase A (SrtA), a key transpeptidase for bacterial virulence. Among these active flavonoids, 7-hydroxy-6-methoxy-flavanone (3) and formononetin (10) were identified as compounds with promising SrtA inhibitory activity. These compounds also exhibited inhibitory activity against S. aureus cell clumping to fibrinogen. The suppression of cell-clumping activity indicates the potential of these compounds in the treatment of S. aureus infections via the inhibition of SrtA.