Embryonic Exposure to Cigarette Smoke Extract Impedes Skeletal Development and Evokes Craniofacial Defects in Zebrafish.

Exposure to cigarette smoke represents the largest source of preventable death and disease in the United States. This may be in part due to the nature of the delayed harmful effects as well as the lack of awareness of the scope of harm presented by these products. The presence of "light" versions further clouds the harmful effects of tobacco products. While active smoking in expectant mothers may be reduced by educational and outreach campaigns, exposure to secondhand smoke is often involuntary yet may harm the developing embryo. In this study, we show that the main component of secondhand smoke, sidestream cigarette smoke, from several brands, including harm-reduction versions, triggered unsuccessful hatching at 3 dpf and reduced overall survival at 6 dpf in developing zebrafish. At non-lethal concentrations, craniofacial defects with different severity based on the cigarette smoke extract were noted by 6 dpf. All tested products, including harm-reduction products, significantly impacted cartilage formation and/or bone mineralization in zebrafish embryos, independent of whether the bones/cartilage formed from the mesoderm or neural crest. Together, these results in a model system often used to detect embryonic malformations imply that exposure of a woman to secondhand smoke while pregnant may lead to mineralization issues in the skeleton of her newborn, ultimately adding a direct in utero association to the increased fracture risk observed in children of mothers exposed to cigarette smoke.

Red-shifted luciferase-luciferin pairs for enhanced bioluminescence imaging.

Red-shifted bioluminescence reporters are desirable for biological imaging. We describe the development of red-shifted luciferins based on synthetic coelenterazine analogs and corresponding mutants of NanoLuc that enable bright bioluminescence. One pair in particular showed superior in vitro and in vivo sensitivity over commonly used bioluminescence reporters. We adapted this pair to develop a bioluminescence resonance-energy-based Antares reporter called Antares2, which offers improved signal from deep tissues.

A membrane-activatable near-infrared fluorescent probe with ultra-photostability for mitochondrial membrane potentials.

Mitochondrial membrane potential (MMP) is a frequently used indicator for mitochondrial function. Herein, we report a photostable near-infrared (NIR) fluorescent dye for monitoring MMP. This new probe, named NIMAP, is non-fluorescent in aqueous solution and can be activated by cell membranes, providing high fluorescence contrast and low background fluorescence. NIMAP has been validated for monitoring MMP in living mammalian cells and in mice. Due to the large fluorescence response, low fluorescence background, high photostability, and excellent tissue penetration resulting from red-shifted excitation and emission in the "optical window" above 600 nm, broad applications of this new probe are expected.