CXXC5 is a transcriptional activator of Flk-1 and mediates bone morphogenic protein-induced endothelial cell differentiation and vessel formation.

CXXC5 is a member of a small subset of proteins containing CXXC-type zinc-finger domain. Here, we show that CXXC5 is a transcription factor activating Flk-1, a receptor for vascular endothelial growth factor. CXXC5 and Flk-1 were accumulated in nucli and membrane of mouse embryonic stem cells (mESCs), respectively, during their endothelial differentiation. CXXC5 overexpression induced Flk-1 transcription in both endothelium-differentiated mESCs and human umbilical vein endothelial cells (HUVECs). In vitro DNA binding assay showed direct interaction of CXXC5 on the Flk-1 promoter region, and mutation on its DNA-binding motif abolished transcriptional activity. We showed that bone morphorgenetic protein 4 (BMP4) induced CXXC5 transcription in the cells, and inhibitors of BMP signaling suppressed the CXXC5 induction and the consequent Flk-1 induction by BMP4 treatment. CXXC5 knockdown resulted in suppression of BMP4-induced stress fiber formation (56.8 ± 1.3% decrease, P<0.05) and migration (54.6 ± 1.9% decrease, P<0.05) in HUVECs. The in vivo roles of CXXC5 in BMP-signaling-specific vascular development and angiogenesis were shown by specific defect of caudal vein plex vessel formation (57.9 ± 11.8% decrease, P<0.05) in cxxc5 morpholino-injected zebrafish embryos and by suppression of BMP4-induced angiogenesis in subcutaneously injected Matrigel plugs in CXXC5(-/-) mice. Overall, CXXC5 is a transcriptional activator for Flk-1, mediating BMP signaling for differentiation and migration of endothelial cell and vessel formation.

Sur8/Shoc2 involves both inhibition of differentiation and maintenance of self-renewal of neural progenitor cells via modulation of extracellular signal-regulated kinase signaling.

Sur8/Shoc2 is a scaffold protein that regulates the Ras-extracellular signal-regulated kinase (ERK) pathway. However, the roles of Sur8 in cellular physiologies are poorly understood. In this study, Sur8 was severely repressed in the course of neural progenitor cell (NPC) differentiation in the cerebral cortex of developing rat embryos. Similarly, Sur8 was also critically reduced in cultured NPCs, which were induced differentiation by removal of basic fibroblast growth factor (bFGF). Sur8 regulation occurs at the protein level rather than at the mRNA level as revealed by both in situ hybridization and reverse transcriptase polymerase chain reaction analyses. The role of Sur8 in NPC differentiation was confirmed by lentivirus-mediated Sur8 knockdown, which resulted in increased differentiation, whereas exogenous expression of Sur8 inhibited differentiation. Contrastingly, NPC proliferation was promoted by overexpression, but was suppressed by Sur8 knockdown. The role of Sur8 as an antidifferentiation factor in the developing rat brain was confirmed by an ex vivo embryo culture system combined with the lentivirus-mediated Sur8 knockdown. The numbers and sizes of neurospheres were reduced, but neuronal outgrowth was enhanced by the Sur8 knockdown. The Ras-ERK pathway is involved in Sur8-mediated regulations of differentiation, as the treatment of ERK kinase (MEK) inhibitors blocks the effects of Sur8. The regulations of NPCs' differentiation and proliferation by the Ras-ERK pathway were also shown by the rescues of the effects of bFGF depletion, neuronal differentiation, and antiproliferation by epidermal growth factor. In summary, Sur8 is an antidifferentiation factor that stimulates proliferation for maintenance of self-renewal in NPCs via modulation of the Ras-ERK pathway.

Wasting condition as a marker for severe disease in pediatric Crohn's disease.

ABSTRACT: Several studies have shown an association between sarcopenia and clinical outcomes in patients with Crohn's disease (CD). However, studies have shown different results, and the association between prognosis and wasting conditions in pediatric patients with CD is uncertain. In this study, we evaluated the clinical significance of wasting in pediatric CD patients.We retrospectively analyzed data on wasting syndrome in patients diagnosed with CD at the Pediatric Department of Gachon University Gil Medical Center between January 1995 and January 2018.Of 105 patients diagnosed with CD, 39.0% were classified into the wasting group (weight-for-age z-score ≤-1) and 61.0% into the nonwasting group (weight-for-age z-score >-1). Height-for-age and body mass index-for-age z-scores at the time of diagnosis were significantly associated with wasting (P < .001 and P < .001, respectively). Additionally, wasting was significantly associated with low levels of hemoglobin (P < .001), high levels of inflammatory markers, including C-reactive protein (P = .005) and erythrocyte sedimentation rate (P = .04), and a smaller surface area of the gluteus maximus muscle (P < .001). Interestingly, since the site of CD involvement and other markers for nutrition did not correlate with wasting syndrome, wasting appears to be a marker for the severity of pediatric CD. Lastly, the wasting group tended to have a greater use of biologic therapy after first-line therapy failed to improve wasting syndrome.Wasting syndrome, including sarcopenia, can serve as a marker for the severity of pediatric CD.

Wnt5a is required for endothelial differentiation of embryonic stem cells and vascularization via pathways involving both Wnt/beta-catenin and protein kinase Calpha.

In this study, we examined the signaling pathways activated by Wnt5a in endothelial differentiation of embryonic stem (ES) cells and the function of Wnt5a during vascular development. We first found that Wnt5a(-/-) mouse embryonic stem (mES) cells exhibited a defect in endothelial differentiation, which was rescued by addition of Wnt5a, suggesting that Wnt5a is required for endothelial differentiation of ES cells. Involvement of both beta-catenin and protein kinase (PK)Calpha pathways in endothelial differentiation of mES cells requiring Wnt5a was indicated by activation of both beta-catenin and PKCalpha in Wnt5a(+/-) but not in Wnt5a(-/-) mES cells. We also found that beta-catenin or PKCalpha knockdowns inhibited the Wnt5a-induced endothelial differentiation of ES cells. Moreover, the lack of endothelial differentiation of Wnt5a(-/-) mES cells was rescued only by transfection of both beta-catenin and PKCalpha, indicating that both genes are required for Wnt5a-mediated endothelial differentiation. Wnt5a was also found to be essential for the differentiation of mES cells into immature endothelial progenitor cells, which are known to play a role in repair of damaged endothelium. Furthermore, a defect in the vascularization of the neural tissue was detected at embryonic day 14.5 in Wnt5a(-/-) mice, implicating Wnt5a in vascular development in vivo. Thus, we conclude that Wnt5a is involved in the endothelial differentiation of ES cells via both Wnt/beta-catenin and PKC signaling pathways and regulates embryonic vascular development.

Valproic acid induces differentiation and inhibition of proliferation in neural progenitor cells via the beta-catenin-Ras-ERK-p21Cip/WAF1 pathway.

BACKGROUND: Valproic acid (VPA), a commonly used mood stabilizer that promotes neuronal differentiation, regulates multiple signaling pathways involving extracellular signal-regulated kinase (ERK) and glycogen synthase kinase3beta (GSK3beta). However, the mechanism by which VPA promotes differentiation is not understood. RESULTS: We report here that 1 mM VPA simultaneously induces differentiation and reduces proliferation of basic fibroblast growth factor (bFGF)-treated embryonic day 14 (E14) rat cerebral cortex neural progenitor cells (NPCs). The effects of VPA on the regulation of differentiation and inhibition of proliferation occur via the ERK-p21Cip/WAF1 pathway. These effects, however, are not mediated by the pathway involving the epidermal growth factor receptor (EGFR) but via the pathway which stabilizes Ras through beta-catenin signaling. Stimulation of differentiation and inhibition of proliferation in NPCs by VPA occur independently and the beta-catenin-Ras-ERK-p21Cip/WAF1 pathway is involved in both processes. The independent regulation of differentiation and proliferation in NPCs by VPA was also demonstrated in vivo in the cerebral cortex of developing rat embryos. CONCLUSION: We propose that this mechanism of VPA action may contribute to an explanation of its anti-tumor and neuroprotective effects, as well as elucidate its role in the independent regulation of differentiation and inhibition of proliferation in the cerebral cortex of developing rat embryos.

Behçet's disease with multiple splenic abscesses in a child.

We report the case of a 5-year-old male patient with multiple aseptic splenic abscesses associated with Behçet's disease. The patient visited Gachon University Gil Hospital with fever, abdominal pain, and acute watery and bloody diarrhea, and reported a 2-year history of chronic abdominal pain and intermittent watery diarrhea. He was treated with antibiotics at a local clinic for fever and cervical lymph node swelling. Additionally, he had recurrent stomatitis. A colonoscopy showed multiple well-demarcated ulcerations throughout the colon, and abdominal computed tomography showed multiple splenic abscesses. Pathergy and HLA-B51 tests were positive. Investigations did not reveal any infectious organisms in the aspirate obtained via ultrasound-guided fine needle aspiration. After steroid treatment, all symptoms and multiple aseptic splenic abscesses resolved. However, oral ulcers, genital ulcers, and abdominal pain recurred after tapering the steroids. Infliximab treatment improved the patient's symptoms. However, 5 months after the treatment, the symptoms recurred. The treatment was changed to include adalimumab. Subsequently, the patient's symptoms resolved and colonoscopic findings improved. No recurrence was noted after 3 months of follow-up.