High content screening of CXCR2-dependent signalling pathways.
Stimulation of CXC-type chemokine receptor 2 (CXCR2)-transfected cells by Gro-alpha or IL-8 induced (i) CXCR2 internalization, (ii) phosphorylation of ERK1/2 (pERK) and (iii) translocation of nuclear factor of activated T cells (NFAT) into the nucleus. Employing high content screening (HCS; i.e. fluorimetric imaging combined with image analysis) these three ligand-induced events were quantified by using a CXCR2-specific antibody, an antibody recognizing phosphorylated ERK1/2 (pERK) and a red fluorescent protein (RFP) in fusion to transiently overexpressed NFAT, respectively. As an RFP, we applied a recently developed mutant of an Entacmaea quadricolor fluorescent protein with favorable properties for HCS, such as high fluorescence brightness, photostability, large Stokes shift, and stability with regard to formaldehyde. Receptor internalization was closely coupled with ERK signalling both when analyzed in regard of stimulation by physiological CXCR2 ligands and when observed in the presence of antagonistic test compounds. A means of increasing the throughput or of broadening the pharmacological characterization of test compounds is the use of multiplexed imaging. Indeed, CXCR2 internalization could be multiplexed with the NFAT nuclear translocation by fixation at approximately 45 min after Gro-alpha stimulation. This multiplexing demonstrated that Gro-alpha-induced CXCR2 internalization was tightly correlated with Gro-alpha-induced NFAT translocation, also on the single cell level. The analysis of ERK phosphorylation, NFAT translocation and receptor internalization enabled the profiling of antagonistic test compounds with respect to G-protein signalling and possible receptor desensitization liabilities.
Wolff
Michael
M
Department of Integrated Lead Discovery Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach, Germany.
Kredel
Simone
S
Haasen
Dorothea
D
Wiedenmann
Jörg
J
Nienhaus
G Ulrich
GU
Kistler
Barbara
B
Oswald
Franz
F
Heilker
Ralf
R
D000818:Animals; D016466:CHO Cells; D002118:Calcium / Q000378:metabolism; D002460:Cell Line; D054360:Chemokine CXCL1 / Q000378:metabolism; D006224:Cricetinae; D003412:Cricetulus; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism*; D057166:High-Throughput Screening Assays; D006801:Humans; D016209:Interleukin-8 / Q000378:metabolism; D008164:Luminescent Proteins / Q000235:genetics; D050778:NFATC Transcription Factors / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D010766:Phosphorylation; D021381:Protein Transport; D023063:Receptors, Interleukin-8B / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000235:genetics; D015398:Signal Transduction; D014162:Transfection; D000097573:Red Fluorescent Protein
D002118:Calcium; D054360:Chemokine CXCL1; D048049:Extracellular Signal-Regulated MAP Kinases; D016209:Interleukin-8; D008164:Luminescent Proteins; D050778:NFATC Transcription Factors; D023063:Receptors, Interleukin-8B; D011993:Recombinant Fusion Proteins; D000097573:Red Fluorescent Protein