Hedgehog (Hh)-Patched1 (Ptch1) signaling plays essential roles in various developmental processes, but little is known about its role in postnatal homeostasis. Here, we demonstrate regulation of postnatal bone homeostasis by Hh-Ptch1 signaling. Ptch1-deficient (Ptch1+/-) mice and patients with nevoid basal cell carcinoma syndrome showed high bone mass in adults. In culture, Ptch1+/- cells showed accelerated osteoblast differentiation, enhanced responsiveness to the runt-related transcription factor 2 (Runx2), and reduced generation of the repressor form of Gli3 (Gli3rep). Gli3rep inhibited DNA binding by Runx2 in vitro, suggesting a mechanism that could contribute to the bone phenotypes seen in the Ptch1 heterozygotes. Moreover, systemic administration of the Hh signaling inhibitor cyclopamine decreased bone mass in adult mice. These data provide evidence that Hh-Ptch1 signaling plays a crucial role in postnatal bone homeostasis and point to Hh-Ptch1 signaling as a potential molecular target for the treatment of osteoporosis.
Our results suggest that D2-40 is a useful antibody for immunohistochemical discrimination between KHE and TA. In addition, the difference of immunostaining pattern of D2-40 is limited to the peripheral area of capillary proliferation and surrounding dilated vessels; therefore, it is suggested that KHE and TA may reflect different stages in the evolution of a single entity. Namely, they may originate from stem cells possessing the characteristics of both lymphatic and blood vessel endothelial lineages.
Background: Loss of NF1 gene function predisposes individuals to develop NF1-associated tumors, for which there are no known biomarkers/therapeutic targets. Results: TCTP was up-regulated in NF1-associated tumors and enhanced their growth via its positive feedback to the mTOR signaling, which was inhibited by artesunate/rapamycin. Conclusion: TCTP is a novel target functionally implicated in NF1 tumorigenesis. Significance: TCTP could serve as a biomarker/therapeutic target for NF1-associated tumors.
Risk factors for recurrence can be analyzed in detail using color Doppler-EUS. Further investigation using color Doppler-EUS may enable us to select the optimal way to treat esophageal varices to prevent recurrence.
Plexiform and ⁄ or dermal neurofibromas are nerve sheath tumors of the peripheral nervous system that are usually present in individuals with neurofibromatosis type 1 (NF1). Neurofibromas arise from Schwann cells with biallelic inactivation of NF1, the gene that encodes neurofibromin. This protein is responsible for regulation of the Ras-mediated pathway, which has been shown to play a crucial role in epithelial-to-mesenchymal transition (EMT). EMT is a biological process that occurs during embryogenesis and wound healing and is involved in pathological processes such as organ fibrosis and cancer metastasis. However, the relationship between neurofibromin and EMT has not been elucidated. We investigated whether the EMT-related signaling pathway was upregulated in NF1-associated neurofibromas and Schwann cells by assessing the expression levels of the EMTrelated transcription factors Snail, Slug, Twist, ZEB1 and ZEB2.Immunohistochemical studies and quantitative reverse transcription polymerase chain reaction revealed an increase in the expression levels of EMT-related transcription factors in neurofibroma specimens and NF1-derived Schwann cells (sNF96.2). In addition, the silencing of NF1 by siRNA induced the expression of EMT-related transcription factors in normal human Schwann cells and in epithelial-like breast cancer cells. Our findings suggest that the loss of neurofibromin activated the EMT-related signaling pathway and that the excessive mesenchymal reaction may play a key role in the development of NF1-associated neurofibromas.
These results suggest that patients showing anterior branch dominance and rapid hepatofugal flow velocity in the LGV on CD-EUS examination may have a high risk of an early recurrence of esophageal varices.
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