Alternative activation of hedgehog pathway induced by ultraviolet B radiation: preliminary study.

BACKGROUND: There is still much ambiguity in studies of Sonic hedgehog (Shh) pathways and its dysregulation. Some studies concerning the role of the Shh pathway in basal cell carcinoma (BCC) have been conducted, but there is a lack of studies about Shh pathway dysregulation under the influence of ultraviolet (UV)B radiation. AIM: To evaluate skin expression of Shh, Ptch1, Ptch2, Smo and Gli1 proteins in BCCs with and without the influence of UVB radiation. METHODS: In total, 34 healthy controls (HCs) and 42 patients with nodular BCC were recruited into the study. Patients were divided into five groups (A-E), depending on UVB dose received and BCC status. In all skin specimens, expression of Shh, Ptch1, Ptch2, Smo and Gli1 protein was evaluated. RESULTS: Comparing the BCC group with the HC group, there was significantly higher expression of Shh, Ptch1, Ptch2, Smo and Gli1 proteins. Expression of Ptch2, Smo and Gli1 was increased in response to UVB doses of 3 MED (minimal erythema dose), whereas expression of Ptch1 and Shh was unaffected. CONCLUSION: The lack of change in expression of Shh and Ptch1 after exposure to UVB suggests that the Shh pathway may be activated through a noncanonical pathway under the influence of strong UVB doses.

The role of T-regulatory cells and Toll-like receptors 2 and 4 in atopic dermatitis.

Regulatory T cells (Tregs), toll-like receptors (TLRs) and interleukin-17 (IL-17) play important role in inflammatory diseases; however, their relevance in atopic dermatitis (AD) pathogenesis is not clear. The aim of study was to evaluate the number of circulating Tregs and peripheral blood mononuclear cells (PBMC) expressing TLR2 and TLR4 receptors in patients with AD. PBMC and CD4+/CD25(high) + Tregs were isolated from the whole blood of 32 AD patients and 36 healthy volunteers. Expression of CD4+CD25+, TLR2 and TLR4 receptors and IL 17+ was assessed with the flow cytometry. In the peripheral blood of AD patients, the percentage of Tregs was significantly higher when compared with the controls (P=0.0003). The number of TLR2+PBMC and TLR4+ PBMC in AD patients was significantly lower than in the controls (P=0.035; P=0.001, respectively). Also the percentages of Tregs with expression of both TLR2+ and TLR4+ in AD patients were significantly lower than in the control (3.85 versus 21.6, P<0.0001; 2.2 versus 17.6, P<0.0001, simultaneously). The percentage of CD4+/CD25high+/FOXP3+ Treg lymphocytes with expression of IL-17 was significantly higher in AD group than in healthy subjects (0.3% versus 0.06%; P=0.011). Distinct number of Tregs and various distribution of TLR2 and TLR4 expression on PBMC in AD patients suggest their contribution in the pathogenesis of AD.