No abstract

Emerging evidence indicates that microRNAs (miRNAs) have important roles in regulating osteogenic differentiation and bone formation. Thus far, no study has established the pathophysiological role for miRNAs identified in human osteoporotic bone specimens. Here we found that elevated miR-214 levels correlated with a lower degree of bone formation in bone specimens from aged patients with fractures. We also found that osteoblast-specific manipulation of miR-214 levels by miR-214 antagomir treatment in miR-214 transgenic, ovariectomized, or hindlimb-unloaded mice revealed an inhibitory role of miR-214 in regulating bone formation. Further, in vitro osteoblast activity and matrix mineralization were promoted by antagomir-214 and decreased by agomir-214, and miR-214 directly targeted ATF4 to inhibit osteoblast activity. These data suggest that miR-214 has a crucial role in suppressing bone formation and that miR-214 inhibition in osteoblasts may be a potential anabolic strategy for ameliorating osteoporosis.

Three novel copolymers containing alternating 1,4-bis(phenylethenyl)benzene, 1,4-bis(phenylethenyl)-2,5dimethoxybenzene or 1,5-bis(phenylethenyl)naphthalene chromophores and crown ether (CE) spacers within the polymer backbone were synthesized by the Wittig polycondensation reaction. These copolymers exhibit good thermal stability (decomposition temperature around 380-411 uC). Photoluminescence (PL) and electroluminescence (EL) color can be easily tuned in these copolymers by simply changing the structure of the chromophores. Excimer emission is responsible for the changes in the PL spectra on going from solution to the thin films. Typical light-emitting electrochemical cell (LEC) behavior is observed in the EL devices with these copolymers as both electronic and ionic conductors. The turn-on voltage for emission is at 13.9 V, in forward bias, and at 24.4 V, under reverse bias. Efficient LECs with low turn-on voltages can be demonstrated upon addition of poly(ethylene oxide) (PEO) into the active layers. CE spacers in these copolymers contribute to the increasing ionic conductivity and the improvement in the morphology of the active layers. The d.c. response and a.c. impedance behaviors of the LECs with PEO were investigated, and the results indicate the operation of these LECs corresponds to the electrochemical doping mechanism.