Novel irreversible fluorescent probes targeting the 18 kDa translocator protein: synthesis and biological characterization.
The 18 kDa translocator protein (TSPO) is a mitochondrial protein whose basal density is altered in several diseases, with the result that the evaluation of its expression levels by means of molecular imaging techniques represents a promising diagnostic approach. Experimental procedures using a labeled ligand often cause loss of the bound probe, and consequently high affinity ligands covalently binding the receptor protein are needed to overcome this problem. We have previously described a series of N,N-dialkyl-(2-phenylindol-3-yl)glyoxylamides as potent and selective TSPO ligands. Starting from these derivatives, we designed novel TSPO irreversible ligands bearing an electrophilic isothiocyanato group (7, 8), together with an irreversible NBD-fluorescent probe (18). The TSPO affinity of the new irreversible ligands was measured on rat tissue homogenates by [(3)H]Ro 5-4864 radiobinding kinetic assays, all compounds showing high affinities for the target protein. Further biological characterization of the fluorescent irreversible TSPO probe 18 was carried out by using fluorescent spectroscopy in human glioma cells.
Taliani
Sabrina
S
Dipartimento di Scienze Farmaceutiche, Università di Pisa, Pisa, Italy. taliani@farm.unipi.it
Da Pozzo
Eleonora
E
Bellandi
Marusca
M
Bendinelli
Sara
S
Pugliesi
Isabella
I
Simorini
Francesca
F
La Motta
Concettina
C
Salerno
Silvia
S
Marini
Anna Maria
AM
Da Settimo
Federico
F
Cosimelli
Barbara
B
Greco
Giovanni
G
Novellino
Ettore
E
Martini
Claudia
C
D009327:4-Chloro-7-nitrobenzofurazan / Q000031:analogs & derivatives* / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology; D000818:Animals; D001667:Binding, Competitive; D002352:Carrier Proteins / Q000378:metabolism*; D045744:Cell Line, Tumor; D002463:Cell Membrane Permeability; D005456:Fluorescent Dyes / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology; D006801:Humans; D066298:In Vitro Techniques; D017879:Isothiocyanates / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology; D007668:Kidney / Q000378:metabolism; D007700:Kinetics; D008024:Ligands; D024101:Mitochondrial Proteins / Q000378:metabolism*; D011485:Protein Binding; D011869:Radioligand Assay; D051381:Rats; D018079:Receptors, GABA / Q000378:metabolism*; D011963:Receptors, GABA-A / Q000378:metabolism*; D013050:Spectrometry, Fluorescence; D013329:Structure-Activity Relationship
D002352:Carrier Proteins; D005456:Fluorescent Dyes; D017879:Isothiocyanates; D008024:Ligands; D024101:Mitochondrial Proteins; C550158:N-(5-isothiocyanato-2-phenylindol-3-ylglyoxyl)-N'-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)-1,6-diaminohexane; D018079:Receptors, GABA; D011963:Receptors, GABA-A; C499229:TSPO protein, human; C069997:Tspo protein, rat; D009327:4-Chloro-7-nitrobenzofurazan