Electrospun semiconducting polymer nanofibers functionalized with specific container molecules have been used for flexible and high-performance chemical sensors.
Prohibitin (PHB) is a multifunctional protein conserved in eukaryotic systems and shows various expression levels in tumor cells. However, regulation of PHB is not clearly understood. Here, we focused on the regulation of PHB expression by Wnt signaling, one of dominant regulatory signals in various leukemic cells. High mRNA levels of PHB were found in half of clinical leukemia samples. PHB expression was increased by inhibition of the MAPK pathway and decreased by activation of EGF signal. Although cell proliferating signals downregulated the transcription of PHB, treatment with lithium chloride, an analog of the Wnt signal, induced PHB level in various cell types. We identified the TCF-4/LEF-1 binding motif, CATCTG, in the promoter region of PHB by site-directed mutagenesis and ChIP assay. This β-catenin-mediated activation of PHB expression was independent of c-MYC activation, a product of Wnt signaling. These data indicate that PHB is a direct target of β-catenin and the increased level of PHB in leukemia can be regulated by Wnt signaling.
Background
Spondyloarthritis (SpA) is a chronic inflammatory disease that results in bone ankylosis. The tissue renin-angiotensin system (RAS), updated with new components, is an emerging phenomenon possibly implicated in SpA-associated bone changes. Therefore, we sought to determine the mechanism underlying this relationship.
Methods
Sakaguchi (SKG) mice injected with curdlan (SKGc), animal models for SpA, were treated with the RAS modulators, angiotensin II receptor blockers (ARBs) or angiotensin-converting enzyme inhibitors (ACEis). Disease activity was assessed using clinical scores and computed tomography scans. Mouse primary bone marrow monocytes (BMMs), osteoblast (OB) progenitor cells, peripheral blood monocytes (PBMCs), and bone-derived cells (BdCs) from patients with radiographic axial SpA (r-axSpA) were used to investigate the role of RAS in SpA pathogenesis.
Results
The expression of RAS components was significantly high in SKGc mouse joints, wherein ARBs significantly reduced erosion and systemic bone loss, whereas ACEis did not. Osteoclast (OC) differentiation from primary BMMs, mediated by TRAF6, was inhibited by ARBs but promoted by ACEis; the modulators also exerted opposite effects on OB differentiation. Expression of RAS molecules was higher in PBMCs and BdCs of patients with r-axSpA than in control participants. ARBs inhibited OB differentiation in the BdCs of patients with r-axSpA, whereas ACEi did not. Neither ARBs nor ACEis affected OB differentiation in the control participants.
Conclusions
In SpA, a condition characterized by RAS overexpression, ARBs, but not ACEis, inhibited OC and OB differentiation and bone progression. These findings must be considered when treating patients with SpA using RAS modulators.
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