Alopecia areata. How not to miss Satoyoshi syndrome?

Satoyoshi syndrome is a multisystem disorder of suspected autoimmune etiology, characterized predominantly by alopecia, muscle spasms and diarrhea. Antinuclear antibodies are present in 60% of patients. The syndrome primarily affects girls and young women. Trichoscopy shows regularly distributed yellow dots, indistinguishable from typical alopecia areata. The condition may be easily misdiagnosed and treated as alopecia areata. On the basis of an in‐depth analysis of all published cases we developed diagnostic criteria for Satoyoshi syndrome. We also suggest that two subtypes of the disorder should be distinguished, the ANA‐positive Satoyoshi syndrome with generally good response to systemic glucocorticosteroid therapy and the ANA‐negative Satoyoshi with less favorable prognosis. In our opinion all patients will alopecia areata (in particular alopecia totalis) should be inquired about muscle spasms and diarrhea and tested for antinuclear antibodies to decrease the risk of missing Satoyoshi syndrome.     

miR-20a represses endothelial cell migration by targeting MKK3 and inhibiting p38 MAP kinase activation in response to VEGF

Endothelial cell migration induced in response to vascular endothelial growth factor (VEGF) is a crucial step of angiogenesis and it depends on the activation of the p38 MAP-kinase pathway downstream of VEGFR2. In this study, we investigated the role of microRNAs (miRNAs) in regulating these processes. We found that the VEGF-induced p38 activation and cell migration are modulated by overexpression of Argonaute 2, a key protein in the functioning of miRNAs. Thereafter, we found that miR-20a expression is increased by VEGF and that its ectopic expression inhibits VEGF-induced actin remodeling and cell migration. Moreover, the expression of miR-20a impairs the formation of branched capillaries in a tissue-engineered model of angiogenesis. In addition, the lentivirus-mediated expression of miR-20a precursor (pmiR-20a) is associated with a decrease in the VEGF-induced activation of p38. In contrast, these processes are increased by inhibiting miR-20a with a specific antagomir. Interestingly, miR-20a does not modulate VEGFR2 or p38 protein expression level. miR-20a does not affect either the expression of other known actors of the p38 MAP kinase pathway except MKK3. Indeed, by using quantitative PCR and Western Blot analysis, we found that pmiR-20a decreases the expression of MKK3 and we obtained evidence indicating that miR-20a specifically binds to the 3′UTR region of MKK3 mRNA. In accordance, the VEGF-induced activation of p38 and cell migration are impaired when the MKK3 expression is knocked down by siRNA. We conclude that miR-20a acts in a feedback loop to repress the expression of MKK3 and to negatively regulate the p38 pathway-mediated VEGF-induced endothelial cell migration and angiogenesis.