Designer Thiopurine-analogues for Optimised Immunosuppression in Inflammatory Bowel Diseases.
OBJECTIVE
The clinical use of azathioprine and 6-mercaptopurine is limited by their delayed onset of action and potential side effects such as myelosuppression and hepatotoxicity. As these drugs specifically target the Vav1/Rac1 signalling pathway in T lamina propria lymphocytes via their metabolite 6-thio-GTP, we studied expression and optimised suppression of this pathway in inflammatory bowel diseases [IBD].


METHODS
Rac1 and Vav1 expressions were analysed in mucosal immune cells in IBD patients. Targeted molecular modelling of the 6-thio-GTP molecule was performed to optimise Rac1 blockade; 44 modified designer thiopurine-analogues were tested for apoptosis induction, potential toxicity, and immunosuppression. Activation of the Vav1/Rac1 pathway in lymphocytes was studied in IBD patients and in lamina propria immune cells in the presence or absence of thiopurine-analogues.


RESULTS
Several thiopurine-analogues induced significantly higher T cell apoptosis than 6-mercaptopurine. We identified a compound, denoted B-0N, based on its capacity to mediate earlier and stronger induction of T cell apoptosis than 6-mercaptopurine. B-0N-treatment resulted in accelerated inhibition of Rac1 activity in primary peripheral blood T cells as well as in intestinal lamina propria immune cells. Compared with 6-thio-GTP and 6-mercaptopurine, B-0N-treatment was associated with decreased myelo- and hepatotoxicity.


CONCLUSIONS
The Vav1/Rac1 pathway is activated in mucosal immune cells in IBD. The designer thiopurine-analogue B-0N induces immunosuppression more potently than 6-mercaptopurine.
Department of Medicine 1, Friedrich-Alexander-University Erlangen-Nuremberg, Erlangen, Germany.
Imke
I
Atreya
Department of Medicine, University of Mainz, Mainz, Germany.
Alexandra
A
Diall
Max Planck Institute of Molecular Physiology, Dortmund, Germany.
Radovan
R
Dvorsky
Department of Medicine 1, Friedrich-Alexander-University Erlangen-Nuremberg, Erlangen, Germany.
Raja
R
Atreya
Institute of Toxicology; University Hospital of Düsseldorf, Düsseldorf, Germany.
Christian
C
Henninger
JenaBioscience GmbH, Jena, Germany.
Mathias
M
Grün
Dr Margarete Fischer-Bosch-Institute of Clinical Pharmacology, Stuttgart, Germany University of Tuebingen, Tuebingen, Germany.
Ute
U
Hofmann
Dr Margarete Fischer-Bosch-Institute of Clinical Pharmacology, Stuttgart, Germany University of Tuebingen, Tuebingen, Germany.
Elke
E
Schaeffeler
Department of Medicine 1, Friedrich-Alexander-University Erlangen-Nuremberg, Erlangen, Germany.
Rocío
R
López-Posadas
London Research Institute, Cancer Research UK, London, UK.
Ilse
I
Daehn
Department of Medicine 1, Friedrich-Alexander-University Erlangen-Nuremberg, Erlangen, Germany.
Stefanie
S
Zenker
Department of Medicine 1, Friedrich-Alexander-University Erlangen-Nuremberg, Erlangen, Germany.
Michael
M
Döbrönti
Department of Medicine 1, Friedrich-Alexander-University Erlangen-Nuremberg, Erlangen, Germany.
Clemens
C
Neufert
Department of Medicine 1, Friedrich-Alexander-University Erlangen-Nuremberg, Erlangen, Germany.
Ulrike
U
Billmeier
Department of Medicine 1, Friedrich-Alexander-University Erlangen-Nuremberg, Erlangen, Germany.
Sebastian
S
Zundler
Institute of Toxicology; University Hospital of Düsseldorf, Düsseldorf, Germany.
Gerhard
G
Fritz
Dr Margarete Fischer-Bosch-Institute of Clinical Pharmacology, Stuttgart, Germany Department of Clinical Pharmacology, University Hospital Tuebingen, Tuebingen, Germany Department of Pharmacy and Biochemistry, University Tuebingen, Tuebingen, Germany.
Matthias
M
Schwab
Department of Medicine 1, Friedrich-Alexander-University Erlangen-Nuremberg, Erlangen, Germany markus.neurath@uk-erlangen.de.
Markus F
MF
Neurath
D017209:Apoptosis / Q000187:drug effects; D015415:Biomarkers / Q000378:metabolism; D016022:Case-Control Studies; D015198:Designer Drugs / Q000494:pharmacology* / Q000627:therapeutic use; D015195:Drug Design; D006801:Humans; D007166:Immunosuppressive Agents / Q000494:pharmacology* / Q000627:therapeutic use; D015212:Inflammatory Bowel Diseases / Q000188:drug therapy* / Q000276:immunology / Q000378:metabolism; D007413:Intestinal Mucosa / Q000187:drug effects* / Q000276:immunology / Q000378:metabolism; D015122:Mercaptopurine / Q000031:analogs & derivatives* / Q000494:pharmacology* / Q000627:therapeutic use; D051567:Proto-Oncogene Proteins c-vav / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D013601:T-Lymphocytes / Q000378:metabolism; D020830:rac1 GTP-Binding Protein / Q000378:metabolism
C000618571:B-0N compound; D015415:Biomarkers; D015198:Designer Drugs; D007166:Immunosuppressive Agents; D051567:Proto-Oncogene Proteins c-vav; C107953:RAC1 protein, human; C496618:VAV1 protein, human; D015122:Mercaptopurine; D020830:rac1 GTP-Binding Protein
6-mercaptopurine; T cells; apoptosis