Fibrodysplasia ossificans progressiva (FOP) is a rare genetic disease characterized by extraskeletal bone formation through endochondral ossification. FOP patients harbor point mutations in ACVR1 (also known as ALK2), a type I receptor for bone morphogenetic protein (BMP). Two mechanisms of mutated ACVR1 (FOP-ACVR1) have been proposed: ligand-independent constitutive activity and liganddependent hyperactivity in BMP signaling. Here, by using FOP patient-derived induced pluripotent stem cells (FOP-iPSCs), we report a third mechanism, where FOP-ACVR1 abnormally transduces BMP signaling in response to Activin-A, a molecule that normally transduces TGF-β signaling but not BMP signaling. Activin-A enhanced the chondrogenesis of induced mesenchymal stromal cells derived from FOPiPSCs (FOP-iMSCs) via aberrant activation of BMP signaling in addition to the normal activation of TGF-β signaling in vitro, and induced endochondral ossification of FOP-iMSCs in vivo. These results uncover a novel mechanism of extraskeletal bone formation in FOP and provide a potential new therapeutic strategy for FOP.iPSC | fibrodysplasia ossificans progressiva | heterotopic ossification | BMP | TGF H eterotopic ossification (HO) is defined as bone formation in soft tissue where bone normally does not exist. It can be the result of surgical operations, trauma, or genetic conditions, one of which is fibrodysplasia ossificans progressiva (FOP). FOP is a rare genetic disease characterized by extraskeletal bone formation through endochondral ossification (1-6). The responsive mutation for classic FOP is 617G > A (R206H) in the intracellular glycineand serine-rich (GS) domain (7) of ACVR1 (also known as ALK2), a type I receptor for bone morphogenetic protein (BMP) (8-10). ACVR1 mutations in atypical FOP patients have been found also in other amino acids of the GS domain or protein kinase domain (11,12). Regardless of the mutation site, mutated ACVR1 (FOP-ACVR1) has been shown to activate BMP signaling without exogenous BMP ligands (constitutive activity) and transmit much stronger BMP signaling after ligand stimulation (hyperactivity) (12-25).To reveal the molecular nature of how FOP-ACVR1 activates BMP signaling, cells overexpressing FOP-ACVR1 (12-20), mouse embryonic fibroblasts derived from Alk2 R206H/+ mice (21, 22), and cells from FOP patients, such as stem cells from human exfoliated deciduous teeth (23), FOP patient-derived induced pluripotent stem cells (FOP-iPSCs) (24, 25) and induced mesenchymal stromal cells (iMSCs) from FOP-iPSCs (FOP-iMSCs) (26) have been used as models. Among these cells, Alk2 R206H/+ mouse embryonic fibroblasts and FOP-iMSCs are preferred because of their accessibility and expression level of FOP-ACVR1 using an endogenous promoter. In these cells, however, the constitutive activity and hyperactivity is not strong (within twofold normal levels) (22,26). In addition, despite the essential role of BMP signaling in development (27-31), the pre-and postnatal development and growth of FOP patients are almost normal, and H...

Balanced development of excitatory and inhibitory synapses is required for normal brain function, and their imbalance may underlie pathogenesis of neuropsychiatric disorders. Compared with many identified trans-synaptic adhesion complexes that organize excitatory synapses, little is known about organizers specific for inhibitory synapses. Here we report Slit and NTRK-like family member 3 (Slitrk3) as a postsynaptic adhesion molecule that selectively regulates inhibitory synapse development via trans-interaction with axonal tyrosine phosphatase receptor PTPδ. Slitrk3 expressed in fibroblasts triggers only inhibitory presynaptic differentiation in contacting axons of cocultured rat hippocampal neurons. Recombinant Slitrk3 preferentially localizes to inhibitory postsynaptic sites. Slitrk3-deficient mice exhibit decreases in inhibitory but not excitatory synapse number and function in hippocampal CA1 neurons and exhibit increased seizure susceptibility and spontaneous epileptiform activity. Slitrk3 requires trans-interaction with axonal PTPδ to induce inhibitory presynaptic differentiation. These results identify Slitrk3-PTPδ as an inhibitory-specific trans-synaptic organizing complex required for normal functional GABAergic synapse development.

Background: Biologic disease modifying anti-rheumatic drugs (bDMARDs) are recommended for radiographic axial spondyloarthritis (r-axSpA), otherwise known as ankylosing spondylitis, when conventional therapies fail. We report efficacy and safety results of a Phase 3 study of ixekizumab, a high-affinity monoclonal antibody that selectively targets IL-17A, in bDMARDnaïve patients with r-axSpA. Methods: In this randomized, double-blind, Phase 3 study, adult patients with inadequate response/intolerance to NSAIDs, an established diagnosis of r-axSpA, and with radiographic sacroiliitis centrally defined by modified New York criteria and ≥1 spondyloarthritis feature according to Assessment of Spondyloarthritis International Society (ASAS) criteria were recruited from 84 sites (12 countries) in Europe, Asia, and North America. Patients were randomized 1:1:1:1 using a computer-generated random sequence to 80 mg subcutaneous ixekizumab every two (Q2W) or four (Q4W) weeks, 40 mg adalimumab Q2W (active reference arm), or placebo. The primary endpoint was the proportion of patients achieving an ASAS40 response at Week 16. Findings: Between June 20, 2016 and August 22, 2017, 341 patients were randomized to placebo (N=87), adalimumab (N=90), ixekizumab Q2W (N=83), or ixekizumab Q4W (N=81). At Week 16, significantly more patients achieved ASAS40 with ixekizumab Q2W (n=43, 51•8%, p<0•0001), ixekizumab Q4W (n=39, 48•1%, p<0•0001), and adalimumab (n=32, 35•6%; p=0•0053) versus placebo (n=16, 18•4%). One serious infection occurred in each of the ixekizumab Q2W (1•2%), ixekizumab Q4W (1•2%), and adalimumab (1•1%) arms; none were reported with placebo. One (1•1%) Candida infection occurred in the adalimumab arm and one (1•2%) patient receiving ixekizumab Q2W was adjudicated as having probable Crohn's disease. No opportunistic infections, malignancies, or deaths occurred. Interpretation: Each dosing regimen of ixekizumab was superior to placebo for improving r-axSpA signs and symptoms in bDMARD-naïve patients; the safety profile was consistent with previous studies of ixekizumab. The adalimumab control arm performed as expected. Funding: Eli Lilly and Company Research in context Evidence before this study Pubmed was searched using the terms "ankylosing spondylitis", "axial spondyloarthritis", and "disease-modifying anti-rheumatic drugs", including articles through May 30, 2018. Axial spondyloarthritis (axSpA) is a chronic immune-mediated disease characterized by inflammation of the spine and sacroiliac joint (SIJ), peripheral joint involvement, extra articular manifestations, and a strong genetic association with human leukocyte antigen (HLA)-B27. Radiographic axSpA (r-axSpA) was previously classified as ankylosing spondylitis (AS) in 1984 and updated to r-axSpA as part of the ASAS criteria. Both criteria sets require the same radiographically confirmed structural damage to the sacroiliac joint as well as at least one accompanying clinical element. Recommendations for the management of r-axSpA generally include exercise and physiothera...

Neural crest cells (NCCs) are an embryonic migratory cell population with the ability to differentiate into a wide variety of cell types that contribute to the craniofacial skeleton, cornea, peripheral nervous system, and skin pigmentation. This ability suggests the promising role of NCCs as a source for cell-based therapy. Although several methods have been used to induce human NCCs (hNCCs) from human pluripotent stem cells (hPSCs), such as embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs), further modifications are required to improve the robustness, efficacy, and simplicity of these methods. Chemically defined medium (CDM) was used as the basal medium in the induction and maintenance steps. By optimizing the culture conditions, the combination of the GSK3β inhibitor and TGFβ inhibitor with a minimum growth factor (insulin) very efficiently induced hNCCs (70–80%) from hPSCs. The induced hNCCs expressed cranial NCC-related genes and stably proliferated in CDM supplemented with EGF and FGF2 up to at least 10 passages without changes being observed in the major gene expression profiles. Differentiation properties were confirmed for peripheral neurons, glia, melanocytes, and corneal endothelial cells. In addition, cells with differentiation characteristics similar to multipotent mesenchymal stromal cells (MSCs) were induced from hNCCs using CDM specific for human MSCs. Our simple and robust induction protocol using small molecule compounds with defined media enabled the generation of hNCCs as an intermediate material producing terminally differentiated cells for cell-based innovative medicine.

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TRL is associated with resistance to radiotherapy among cervical cancer patients, and MDSC-targeting treatments may have therapeutic potential in these patients.

Granulocyte-colony stimulating factor (G-CSF) producing malignant tumor has been reported to occur in various organs, and has been associated with poor clinical outcome. The aim of this study is to investigate the significance of tumor G-CSF expression in the chemosensitivity of uterine cervical cancer. The clinical data of recurrent or advanced cervical cancer patients who were treated with platinum-based chemotherapy were analyzed. Clinical samples, cervical cancer cell lines, and a mouse model of cervical cancer were employed to examine the mechanisms responsible for the development of chemoresistance in G-CSF-producing cervical cancer, focusing on myeloid-derived suppressor cells (MDSC). As a result, the tumor G-CSF expression was significantly associated with increased MDSC frequencies and compromised survival. In vitro and in vivo experiments demonstrated that the increased MDSC induced by tumor-derived G-CSF is involved in the development of chemoresistance. The depletion of MDSC via splenectomy or the administration of anti-Gr-1 antibody sensitized G-CSF-producing cervical cancer to cisplatin. In conclusion, tumor G-CSF expression is an indicator of an extremely poor prognosis in cervical cancer patients that are treated with chemotherapy. Combining MDSC-targeting treatments with current standard chemotherapies might have therapeutic efficacy as a treatment for G-CSF-producing cervical cancer.