KITLG Mutations Cause Familial Progressive Hyper- and Hypopigmentation
JOURNAL OF INVESTIGATIVE DERMATOLOGY
Authors: Amyere, Mustapha; Vogt, Thomas; Hoo, Joe; Brandrup, Flemming; Bygum, Anette; Boon, Laurence; Vikkula, Miikka
Familial progressive hyper- and hypopigmentation (FPHH) is thought to be an autosomal dominant disorder with reduced penetrance. Clinical signs consist of progressive diffuse, partly blotchy hyperpigmented lesions, multiple cafe-au-lait spots, intermingled with scattered hypopigmented-appearing maculae, and lentigines. FPHH is distinct from familial progressive hyperpigmentation (FPH), in which no hypopigmented features are present, and which is phenotypically and histologically closer to Dyschromatosis Universalis Hereditaria 2 (DUH2). It also differs from the Legius syndrome, characterized by familial cafe-au-lait spots and skin fold freckling, caused by mutations in SPRED1. We performed a genome-wide linkage analysis in seven families with FPHH, and identified linkage on 12q21.12-q22, which overlaps with the DUH2 locus. We investigated whether KITLG in the locus is mutated in FPHH. We discovered three different mutations in four families. A reported FPH substitution was observed in two FPHH families, and two, to our knowledge, previously unreported substitutions, p.Val33Ala and p.Thr34Pro, cosegregated with FPHH in two separate families. All three mutations were located in a conserved beta-strand in KITLG, suggesting its important role in the activation of the KITLG receptor c-Kit. In aggregate, mutations in a single gene cause various pigmentation disorders: FPH, FPHH, and likely DUH2. Therefore, KITLG is an important modulator of skin pigmentation.
Inhibition of microRNA-126 promotes the expression of Spred1 to inhibit angiogenesis in hepatocellular carcinoma after transcatheter arterial chemoembolization: in vivo study
ONCOTARGETS AND THERAPY
Authors: Ji, Jian-Song; Xu, Min; Song, Jing-Jing; Zhao, Zhong-Wei; Chen, Min-Jiang; Chen, Wei-Qian; Tu, Jian-Fei; Yang, Xiao-Ming
MicroRNA-126 (miR-126) has been found to promote angiogenesis, but the underlying mechanisms are still unclear. So, we conducted this study to explore the effect of miR-126 expression on angiogenesis in hepatocellular carcinoma (HCC) after transcatheter arterial chemoembolization (TACE). The expression levels of miR-126 and sprouty-related, EVH1 domain containing protein (Spred) 1 in surgically resected HCC tissue, HCC tissue with TACE+ operation, and tumor-adjacent tissues were determined by quantitative real-time polymerase chain reaction. The expression levels of miR-126, Spred1, and vascular endothelial growth factor were found by quantitative real-time polymerase chain reaction and Western blot. The microvessel density (MVD) of tumor tissues was determined by immunohistochemical staining. The miR-126 and Spred1 expressions in HCC tissue with TACE + operation were elevated and decreased, respectively, as compared to those in surgically resected HCC tissues and tumor-adjacent tissues (all P<0.001), which indicated that the expression of Spred1 was negatively correlated with miR-126 (P<0.001, r=-0.6224). Based on the bioinformatics analysis and luciferase reporter gene activity detection, Spred1 was found to target miR-126 (P<0.001). Inhibition of miR-126 expression reduces the degree of weight loss and tumor size in TACE model rats. The MVD in TACE + operation group was increased compared to that in the control group; inhibition of miR-126 expression had a reversal effect, to a certain extent, on MVD increase after TACE (all P<0.05). Inhibition of miR-126 expression increased Spred1 expression and decreased vascular endothelial growth factor expression (P<0.01). In summary, this study unveiled the potential mechanism by which miR-126 regulates angiogenesis in HCC tissues through embolization treatment by targeting Spred1, and also showed that the feasibility of TACE with the miR-126 inhibitor has a certain value in the medical treatment of HCC.