Adenosine stimulates the recruitment of endothelial progenitor cells to the ischemic heart Involvement of the microrna-150-cxcr4-sdf-1α pathway Emeline Goretti, MSc No conflict of interest
Endothelial Progenitor Cells Cell therapy with EPC : promising option to repair the heart after myocardial infarction Limitation : low number of cells recruited to injured sites Find new strategies to increase the recruitment of EPC to the injured heart 100µM
The CXCR4/SDF-1 axis EPC are recruited by the chemokine stromal cell-derived factor 1α (SDF- 1 ), which binds to the cell surface receptor CXCR4 The capacity of EPC to regenerate the heart is : Inhibited by dys-regulation of the CXCR4/SDF-1 axis (Walter et al, Circ Res 2005 ) Stimulated by up-regulation of the CXCR4/SDF-1 axis (Oh et al, Biochem Biophys Res Commun 2010) Potential target to improve cardiac repair
Adenosine Adenosine is released from dying cardiomyocytes Adenosine binds to 4 types of cell surface G proteincoupled receptors : A 1, A 2A, A 2B and A 3 Adenosine Adenosine regulates angiogenesis (Ernens et al, BBRC 2010) and EPC (Azuaje et al, BMC Syst Biol 2011)
Hypothesis Adenosine regulates the CXCR4/SDF-1 axis stimulation of the recruitment of EPC to the ischemic heart
Methods Isolation PBMCs Adhesion on fibronectin (4 days) Early EPC Characterization Phase contrast DilAcLDL uptake Lectin binding Merge
Adenosine increases CXCR4 mrna expression in EPC Adenosine modulates the expression of various chemokines and their receptors The chemokine receptor CXCR4 is up-regulated The increase of CXCR4 mrna peaks after 2 hours
Adenosine increases cell surface expression of CXCR4 Adenosine modestly increases cell surface CXCR4 Maximal effect after 6 hours Significant effect from 1µmol/L adenosine
Adenosine regulates the expression its receptors A 2A Expression of adenosine receptors A 3 >A 2A >A 2B (A 1 not detected) A 2B Adenosine increases A 2A and A 2B receptors and decreases A 3 receptor A 3
Adenosine receptor signaling pathways Extracell A2b A1/A3 A2a Cell membrane Cytoplasm Nucleus PC bg q i bg bg s Adenylate PLD + 5 Nuc + Ecto 5 Nuc - Ado Kinase Ado Up PA A3 DAG PKC PLC cyclase Channels (K+, mitoch) A1 PIP2 IP3 RhoA Ca++ up A3 Reactive oxygen species PKB =AKT Bad PI3K GRK2 RAS Raf1 MEK (MAPKK) ERK 1/2? Rac Src Ca++ down Adenylate cyclase camp PKA CREB NFKB NFKB p38 CREB CJun Cfos transcription
Adenosine receptor signaling pathways Extracell Pertussis toxin A2b A1/A3 A2a Cell membrane Cytoplasm Nucleus PC bg q i bg bg s Adenylate PLD + 5 Nuc + Ecto 5 Nuc - Ado Kinase Ado Up PA A3 DAG PKC PLC cyclase Channels (K+, mitoch) A1 PIP2 IP3 RhoA Ca++ up A3 Reactive oxygen species PKB =AKT Bad PI3K GRK2 RAS Raf1 MEK (MAPKK) ERK 1/2? Rac Src Ca++ down Adenylate cyclase camp PKA CREB NFKB NFKB p38 CREB CJun Cfos transcription
Signalling pathway involved in the effect of adenosine on CXCR4 (1) G i proteins are not involved in the increase of CXCR4 expression
Signalling pathway involved in the effect of adenosine on CXCR4 (2) Extracell A2b A1/A3 A2a Cell membrane Cytoplasm Chelerythrin PC bg q i bg bg s Adenylate PLD + 5 Nuc + Ecto 5 Nuc - Ado Kinase Ado Up PA A3 DAG PKC PLC cyclase Channels (K+, mitoch) A1 PIP2 IP3 RhoA Ca++ up A3 Reactive oxygen species PKB =AKT Bad PI3K GRK2 RAS Raf1 MEK (MAPKK) ERK 1/2? Rac Src Ca++ down Adenylate cyclase camp PKA CREB H89 PD98059 Nucleus NFKB NFKB p38 CREB CJun Cfos transcription
Signalling pathway involved in the effect of adenosine on CXCR4 (3) Involvement of PKC pathway Contribution of MEK pathway Exclusion of PKA pathway Implication of A2B receptor?
Receptor involved in the effect of adenosine on CXCR4 Antagonist of A 2B receptor (MRS1754) Decrease of CXCR4 sirna A 2B receptor Inhibition of the effect of adenosine on CXCR4 Activation of A 2B receptor increases CXCR4 expression
Adenosine enhances the migration of EPC SDF-1 enhances EPC migration Adenosine amplifies this migration Effect abolished using CXCR4 neutralizing antibodies Conditioned medium from cardiac fibroblasts Adenosine increases EPC migration Effect abolished by CXCR4 neutralizing antibodies
microrna-150 and CXCR4 Tano et al. (PLoS One 2011): microrna-150 regulates the migration of bone marrow-derived mononuclear cells by targeting CXCR4 Involvement of mir-150 in the effect of adenosine on CXCR4?
mir-150 down-regulates CXCR4 under ischemia Adenosine Increases CXCR4 Decreases mir-150 mir-control 3 UTR CXCR4-Luc 3 UTR CXCR4-Luc mir-150 3 UTR CXCR4-Luc Luciferase assay mir-150 targets CXCR4
In vivo effect of adenosine on EPC recruitment Myocardial infarction in rats : ligation of the LAD coronary artery Experimental protocol Day 0 LAD ligation or Sham Day 7 Group 1: saline (control, n=7) Group 2: CADO (2 mg/kg twice daily, n=8) Group 3: CADO + 8-SPT (2 mg/kg twice daily, n=8) Day 60 Sacrifice
Adenosine stimulates EPC recruitment to the infarcted heart CXCR4 and ALDH2 stainings Weak expression in sham and control rats Enhanced expression in border zone of CADO rats effect 8-SPT prevents this
Conclusion Adenosine up-regulates CXCR4 expression in EPC and stimulates their recruitment to the ischemic heart A2B agonists may be tested to stimulate the healing capacity of EPC
Acknowledgments Public Research Centre of Health (CRP-Santé, Luxembourg) Daniel R. Wagner, MD, PhD Yvan Devaux, PhD Magali Rolland-Turner, PhD Mélanie Bousquenaud, PhD Christelle Nicolas, BSC Medical Imaging Plateform (Nancyclotep, France) Gilles Karcher, MD, PhD Pierre-Yves Marie, MD, PhD Fatiha Maskali, PhD Sylvain Poussier, PhD Henri Boutley, BSc Mickaël Lhuillier, BSc