Objective To investigate the role of Ezrin and its phosphorylation(p-Ezrin)in the modulation of rat pulmonary microvascular endothelial cell(PMVEC)injury induced by tumor necrosis factor-α(TNF-α)and the impact of Rac 1. Methods Cultured PMVECs of Sprague-Dawley(SD)rats were randomly divided into time-dependent injury group induced by TNF-αand intervention group in which cells were pretreated with Rac 1 inhibitor (NSC 23766).①In the time-dependent injury group, Western Blot was used to detect the expression of Ezrin and p-Ezrin after 10μg/L TNF-αstimulation for 0,0.25,0.5,1,3,6,12,24 hours.②In the intervention group,after pre-treatment with 200μmol/L NSC 23766 for 0.5 h,PMVECs were treated with 10μg/L TNF-α,and the expression of p-Ezrin was detected by Western Blot after 3 hours. Besides these groups,there were control(1% fetal bovine serum simulation),single NSC 23766 or TNF-α simulation groups. Results ① Few Ezrin expression was found in PMVEC,and TNF-α could not affect Ezrin expression. p-Ezrin protein expression(p-Ezrin/Ezrin,gray scale) of PMVECs at 0 hour after TNF-αstimulation was 0.21±0.03,and elevated at 0.25 hour(0.53±0.19),peaked at 3 hours(1.68±0.30),then it was gradually lowered,but it remained at higher level at 24 hours(0.87±0.18)with significant difference(F=62.200,P=0.000). It demonstrated that TNF-αcould increase Ezrin phosphorylation in a time-dependent manner.②Compared with blank control group,in single NSC 23766 or TNF-αsimulation group, p-Ezrin expression was induced(TNF-αgroup:0.92±0.12 vs. 0.68±0.16,t=-2.864,P=0.020;NSC 23766 group:1.33±0.24 vs. 0.68±0.16,t=-5.429,P=0.000. When NSC 23766 was pre-treated with PMVECs,the expression of p-Ezrin was significantly increased compared with that in single TNF-αsimulation group(2.14±0.18 vs. 0.92±0.12,t=-14.670,P=0.000)with significant difference(F=73.810,P=0.000). Conclusion Ezrin proteins are phosphorylated by TNF-α. Rac 1 signaling pathway inhibition plays an important role in TNF-α-induced injury by up-regulation of p-Ezrin in PMVECs.

A 10-year-old boy presented with a 3-year history of erythematous flat keratotic papules and brown-yellow, nail-like prominent keratotic plaques all over the body surface. Dermatological examination showed verrucous or nail-like prominence over multiple erythematous keratotic plaques on the head, face,trunk and limbs. The lesions, most of which confluenced, were covered with brown-yellow and greasy crusts,and gave a porcupine-like appearance. Skin biopsy of lesions from the back revealed epidermal hyperkeratosis,focal columnar parakeratosis, acanthosis, few acantholytic and dyskeratotic cells in stratum corneum, irregular upward proliferation of dermal papilla cells, and a superficial perivascular lymphocytic infiltration. A diagnosis of ichthyosis hystrix was established based on the histopathological findings. The boy was treated with oral acitretin and topical 0.1% acitretin cream for 8 years. The initial and maximum dose of oral acitretin was 0.5 mg·kg-1·d-1 and 1 mg·kg-1·d-1, respectively. Liver and kidney function, body height and weight were examined during the treatment, and no side effect was observed except for skin xerosis.