Seong-Wook Yun, Cheryl Leong, Duanting Zhai, Yee Ling Tan, Linda Lim, Xuezhi Bi, Jae-Jung Lee, Han Jo Kim, Nam-Young Kang, Shin Hui Ng, Lawrence W. Stanton, and Young-Tae Chang*
National University of Singapore
Proceedings of the National Academy of Sciences of the United States of America 2012, 109, 10214-10217, doi: 10.1073/pnas.1200817109
Highlight by: Dr. Eunha Kim, Massachusetts General Hospital / Harvard Medical School
Molecular imaging is essential tool for current biomedical research fields. Therefore there is explosive increase on demands for the imaging tools and bio-probes for the visualization of cellular function and molecular process in living organism without perturbing their system. Chang and coworkers recently described a discovery of first Neural Stem Cell (NSC)-specific small molecular weight fluorescent chemical compound utilizing combinatorial concept, and they identified the binding target of the compound as intracellular NSC marker Fatty Acid Binding Protein 7 (FABP7) by proteomic analysis. This result clearly shows combinatorial science accelerating the discovery of new novel fluorescent bio-probes.
Continuing their excellent ideas of Diversity Oriented Fluorescence Library (DOFL) strategies, emission intensity based high throughput/content screening of 3,160 fluorescent compounds narrows down the candidates and follow-up further validation allows the authors to find a first NSC specific staining fluorescent compound, CDr3 (λex/em = 579/604 nm, εabs = 1.02 × 106M-1 cm-1, Φem = 0.77), without inhibition of proliferation within 48hrs. In addition, subsequent target identification of the compound by 2D-SDS-PAGE and following MALDI-TOF/TOF MS and MS/MS analysis is convinced them that FABP7 is the binding target of CDr3. It is remarkable that they don’t have to modify the compound for target identification because of their unique strategy. Based on the result, they found that CDr3 selectively stained ReNcell VM human NSC line, having 540-fold higher FABP7 expression level than H1 human ESC. Moreover they can isolate the NSC from heterogeneous cell population, generated from random differentiation of ESC, based on staining pattern of the cells with CDr3.
This interesting result shows that fluorescent compounds are not the simple twinkling tags for labeling certain molecules in cellular environment but it is also the compounds, which can specifically bind with the cellular biomolecules.
- Combinatorial developments of fluorescent library: (a) “Single-Compound Libraries of Organic Materials: Parallel Synthesis and Screening of Fluorescent Dyes” Schiedel, M. S.; Briehn, C. A.; Bäuerle, P., Angew. Chem., Int. Ed. 2001, 40, 4677-4680. (b) “Combinatorial Approach to Organelle-Targeted Fluorescent Library Based on the Styryl Scaffold” Rosania, G. R.; Lee, J. W.; Ding, L.; Yoon, H. –S.; Chang, Y. –T., J. Am. Chem. Soc. 2003, 125, 1130-1131. (c) “Emission Wavelength Prediction of a Full-Color-Tunable Fluorescent Core Skeleton, 9-Aryl-1,2-dihydropyrrolo[3,4-b]indolizin-3-one” Kim, E.; Koh, M.; Lim, B. J.; Park, S. B., J. Am. Chem. Soc. 2011, 133, 6642-6649. (d) “Combinatorial Discovery of Fluorescent Pharmacophores by Multicomponent Reactions in Droplet Arrays” Burchak, O. N.; Mugherli, L.; Ostuni, M.; Lacapère, J. J.; Balakirev, M. Y., J. Am. Chem. Soc. 2011, 133, 10058-10061. (e) “Combinatorial Strategies in Fluorescent Probe Development” Vendrell, M.; Zhai, D.; Er, J. C.; Chang, Y. –T. Chem. Rev. 2012, 112, 4391-4420