The ABCs of PXE Pseudoxanthoma elasticum (PXE) is a genetic disorder caused by mutations in ABCC6 that is characterized by calcium deposition outside of the skeletal system, specifically in the blood vessels, skin, and eyes. Using patient-derived fibroblasts and genetic knockout mouse models, Ziegler et al. demonstrate that ABCC6 mutant cells are osteogenic and that loss of ABCC6 reduces pyrophosphate, an inhibitor of calcification. In mice, ectopic calcification was seen only when ABCC6 was deleted jointly from the liver and from Wnt1+ cells, suggesting systemic and local contributions to the phenotype. Treating mice and cells with a tissue-nonspecific alkaline phosphatase (TNAP) inhibitor prevented pyrophosphate degradation and ectopic calcification progression. Biallelic mutations in ABCC6 cause pseudoxanthoma elasticum (PXE), a disease characterized by calcification in the skin, eyes, and blood vessels. The function of ATP-binding cassette C6 (ABCC6) and the pathogenesis of PXE remain unclear. We used mouse models and patient fibroblasts to demonstrate genetic interaction and shared biochemical and cellular mechanisms underlying ectopic calcification in PXE and related disorders caused by defined perturbations in extracellular adenosine 5′-triphosphate catabolism. Under osteogenic culture conditions, ABCC6 mutant cells calcified, suggesting a provoked cell-autonomous defect. Using a conditional Abcc6 knockout mouse model, we excluded the prevailing pathogenic hypothesis that singularly invokes failure of hepatic secretion of an endocrine inhibitor of calcification. Instead, deficiency of Abcc6 in both local and distant cells was necessary to achieve the early onset and penetrant ectopic calcification observed upon constitutive gene targeting. ABCC6 mutant cells additionally had increased expression and activity of tissue-nonspecific alkaline phosphatase (TNAP), an enzyme that degrades pyrophosphate, a major inhibitor of calcification. A selective and orally bioavailable TNAP inhibitor prevented calcification in ABCC6 mutant cells in vitro and attenuated both the development and progression of calcification in Abcc6−/− mice in vivo, without the deleterious effects on bone associated with other proposed treatment strategies.

We study a phenomenological model in which the simulated packing of hard, attractive spheres on a prolate spheroid surface with convexity constraints produces structures identical to those of prolate virus capsid structures. Our simulation approach combines the traditional Monte Carlo method with a modified method of random sampling on an ellipsoidal surface and a convex hull searching algorithm. Using this approach we identify the minimum physical requirements for nonicosahedral, elongated virus capsids, such as two aberrant flock house virus particles and the prolate prohead of bacteriophage phi29 , and discuss the implication of our simulation results in the context of recent experimental findings. Our predicted structures may also be experimentally realized by the evaporation-driven assembly of colloidal spheres under appropriate conditions.

Balancing the process of bone formation and resorption is important in the maintenance of healthy bone. Therefore, the discovery of novel factors that can regulate bone metabolism remains needed. Irisin is a newly identified hormone-like peptide. Recent studies have reported the involvement of irisin in many physiological and pathological conditions with bone mineral density changes, including osteopenia and osteoporotic fractures. In this study, we generated the first line of Osx-Cre:FNDC5/ irisin KO mice, in which FNDC5/irisin was specifically deleted in the osteoblast lineage. Gene and protein expressions of irisin were remarkably decreased in bones but no significant differences in other tissues were observed in knockout mice. FNDC5/irisin deficient mice showed a lower bone density and significantly delayed bone development and mineralization from early-stage to adulthood. Our phenotypical analysis exhibited decreased osteoblast-related gene expression and increased osteoclast-related gene expression in bone tissues, and reduced adipose tissue browning due to bone-born irisin deletion. By harvesting and culturing MSCs from the knockout mice, we found that osteoblastogenesis was inhibited and osteoclastogenesis was increased. By using irisin stimulated wildtype primary cells as a gainof-function model, we further revealed the effects and mechanisms of irisin on promoting osteogenesis and inhibiting osteoclastogenesis in vitro. In addition, positive effects of exercise, including bone strength enhancement and body weight loss were remarkably weakened due to irisin deficiency. Interestingly, these changes can be rescued by supplemental administration of recombinant irisin during exercise. Our study indicates that irisin plays an important role in bone metabolism and the crosstalk between bone and adipose tissue. Irisin represents a potential molecule for the prevention and treatment of bone metabolic diseases.

Purpose To determine the relationships between radiation doses to the thoracic bone marrow and declines in blood cell counts in non-small cell lung cancer (NSCLC) patients treated with chemoradiation therapy (CRT). Methods and Materials We included 52 patients with NSCLC treated with definitive concurrent carboplatinepaclitaxel and RT. Dose-volume histogram (DVH) parameters for the thoracic vertebrae (TV), sternum, scapulae, clavicles, and ribs were assessed for associations with changes in blood counts during the course of CRT. Linear and logistic regression analyses were performed to identify associations between hematologic nadirs and DVH parameters. A DVH parameter of Vx was the percentage of the total organ volume exceeding × radiation dose. Results Grade ≥3 hematologic toxicity including neutropenia developed in 21% (n=11), leukopenia in 42% (n=22), anemia in 6% (n=3), and throbocytopenia in 2% (n=1) of patients. Greater RT dose to the TV was associated with higher risk of grade ≥3 leukopenia across multiple DVH parameters, including TV V20 (TVV) (odds ratio [OR] 1.06; P=.025), TVV30 (OR 1.07; P=.013), and mean vertebral dose (MVD) (OR 1.13; P=.026). On multiple regression analysis, TVV30 (β = −0.004; P=.018) and TVV20 (β = 0.003; P=.048) were associated with white blood cell nadir. Additional bone marrow sites (scapulae, clavicles, and ribs) did not affect hematologic toxicity. A 20% chance of grade ≥3 leukopenia was associated with a MVD of 13.5 Gy and a TTV30 of 28%. Cutoff values to avoid grade ≤3 leukopenia were MVD ≤23.9 Gy, TVV20 ≤56.0%, and TVV30 ≤52.1%. Conclusions Hematologic toxicity is associated with greater RT doses to the TV during CRT for NSCLC. Sparing of the TV using advanced radiation techniques may improve tolerance of CRT and result in improved tolerance of concurrent chemotherapy.