A novel coumarin-based fluorogenic probe bearing the 2-picolyl unit (1) was developed as a fluorescent chemosensor with high selectivity and suitable affinity in biological systems toward Cu(2+) over other cations tested. The fluorescence on-off mechanism was studied by femtosecond time-resolved fluorescence (TRF) upconversion technique and ab initio calculations. The receptor can be applied to the monitoring of Cu(2+) ion in aqueous solution with a pH span 4-10. To confirm the suitability of 1 for biological applications, we also employed it for the fluorescence detection of the changes of intracellular Cu(2+) in cultured cells. The results indicate that 1 should be useful for the fluorescence microscopic imaging and the study on the biological functions of Cu(2+).

Huntington's disease (HD) is characterized by preferential loss of the medium spiny neurons in the striatum. Using CRISPR/Cas9 and somatic nuclear transfer technology, we established a knockin (KI) pig model of HD that endogenously expresses full-length mutant huntingtin (HTT). By breeding this HD pig model, we have successfully obtained F1 and F2 generation KI pigs. Characterization of founder and F1 KI pigs shows consistent movement, behavioral abnormalities, and early death, which are germline transmittable. More importantly, brains of HD KI pig display striking and selective degeneration of striatal medium spiny neurons. Thus, using a large animal model of HD, we demonstrate for the first time that overt and selective neurodegeneration seen in HD patients can be recapitulated by endogenously expressed mutant proteins in large mammals, a finding that also underscores the importance of using large mammals to investigate the pathogenesis of neurodegenerative diseases and their therapeutics.