‫المعلومات االدارية‬
Project Title - ‫عنوان المشروع‬
INTRACELLULAR CYCLIC AMP INHIBITS LEUKOCYTE
ACTIVATION: IN VIVO VALIDATION OF A NEW THERAPEUTIC
APPROACH AIMING AT PREVENTING TISSUE DEGRADATION
ASSOCIATED WITH INFLAMMATORY DISEASES.
‫ األجازة لطريقة عال جية جديدة تستهدف منع تفتت األنسجة المرتبطة بألمراض‬:‫يعيق تنشيط كريات الدم البيضاء‬cAMP
‫األلتهابية‬
Principal Investigator - ‫الباحث الرئيسي‬
‫رقم الهاتف‬
‫العنوان االلكتروني‬
Telephone
e-mail
01- nada.aladdin@usj.edu.lb
421000(2249)
‫العنوان‬
Address
Riad El
Solh,
damascus
rd
‫الوظيفية‬
Post
Assistant
Professor
‫المؤسسة‬
Institution
University
of St
Joseph,
Faculty of
Medicine
‫االسم‬
Name
Nada
Alaaeddine
Co-Workers - ‫الباحثون المشاركون‬
‫العنوان االلكتروني‬
e-mail
‫المؤسسة‬
‫االسم‬
Institution
Name
John
Di
McGill
University Battista
Laval
Marc Pouliot
University
john.dibattista@mcgill.ca
Marc.Pouliot@crchul.ulaval.ca
2 years
: Duration -‫المدة التعاقدية للمشروع‬
Scientific Information
‫العلمية‬
‫المعلومات‬
ّ
Objectives - ‫الهدف‬
To test the hypothesis that the anti-proinflammatory cytokine, chemokine and
metalloprotease activity of cAMP and its downstream signalling targets can best be
achieved through simultaneous activation of adenylate cyclase (AC) and controlled
inhibition ofphosphodiesterase type IV (PDE-IV) in acute models of inflammation.
‫أالنجازات المحقق‬
Achievements
Our results indicated that, while selective targeting of AC or PDE-IV generally had
limited impact on [cAMP]i levels in neutrophils, monocytes or synovial fibroblasts,
additive and even synergistic increases could be obtained when both were solicited in
concert. While substantial differences in responses were observed between cell types,
both quantitatively and qualitatively, engaging multiple systems induced stronger
[cAMP]i elevations than any one single enzyme system. The combination regimen thus
resulted in the decrease of degradative enzymes and of mRNA expression, and
secretion, of inflammatory cytokines/chemokines. In vivo, single
interventions with forskolin, Ro 20-1724 or PGE2 either showed poor effectiveness in
reducing inflammatory markers, or required high concentrations to do so. In contrast,
the combination regimen was very effective in preventing cytokine release in the
exudates, even at low concentrations.
It has long been appreciated that transient increases in [cAMP] i suppress proinflammatory cytokine, chemokine and metalloprotease gene expression in relevant
target cells.
Attempts to exploit the pharmacotherapeutic potential of these observations focused
on inhibiting PDE-IV, with research and development directed toward achieving
appropriate specificity and affinity for the cell specific isoforms of PDE-IV. This has
proved to be a major challenge as the 4 genes of the PDE-IV family code for some 20
proteins, with the 24 exons of PDE-IVD producing, through multiple promoters and
splicing, some 9 transcripts and proteins. [Furthermore, long-term up regulation of
[cAMP]i results in the expressionand accumulation of short forms of PDE-IV with
relatively long half lives and different inhibitor
Perspectives - ‫آفاق البحث‬
our data support the notion that AC activation in tandem with PDE-IV inhibition
can substantially decrease the release of cytokines, chemokines and/or degradative
enzymes in vitro, ex vivo and in vivo, and that this approach bears significant antiinflammatory potential.
Publications & Communication - ‫المنشورات والمساهمات في المؤتمرات‬
1-SUPPRESSION OF PRO-INFLAMMATORY CYTOKINES AND MATRIX
METALLOPROTEASES IN ACUTE INFLAMMATORY MODELS THROUGH
ENGAGEMENT OF THE CYCLIC AMP/PKA CASCADE1
Jordane Biarc*, Ph.D., Nada Alaaeddine∫, PhD., John A. Di Battista¶, Ph.D.,
Casimiro Gerarduzzi¶, M.Sc., John Antoniou M.D., Ph.D., and Marc Pouliot, Ph.D.*
Submitted for publication.
Presented at the 9th World Congress on Inflammation 2009 in Tokyo
Abstract - ‫موجز عن نتائج البحث‬
ABSTRACT
OBJECTIVES: To test the hypothesis that the anti-proinflammatory cytokine,
chemokine and metalloprotease activity of cAMP and its downstream signalling targets
can best be achieved through simultaneous activation of adenylate cyclase (AC) and
controlled inhibition ofphosphodiesterase type IV (PDE-IV) in acute models of
inflammation.
METHODS: Elevations of intracellular cAMP ([cAMP]i) and PKA activation were
compared under conditions of AC activation (forskolin), PDE-IV inhibition (Ro 201724), or incombination. Prostaglandin E2 (PGE2) was included in these studies as a
known physiological activator of cAMP/PKA pathway. These experiments were
conducted using isolated human neutrophils/monocytes/synovial fibroblasts cultured in
vitro, ex vivo human OA/RA synovial membranes in explant cultures, and in vivo
studies using the murine dorsal air pouch model of acute synovial inflammation.
RESULTS: Controlled and biologically significant elevations in [cAMP]i and
downstream signal amplification were obtained by simultaneous activation of AC and
inhibition of PDE-IV in all cell types tested, an effect mimicked by PGE2 in neutrophils
and synovial fibroblasts. As such,combinations of forskolin, Ro 20-1724, and/or PGE2
were more effective at blocking proinflammatory cytokine, chemokine and matrix
metalloprotease production in vitro, ex vivo,
and in vivo.