Link between immune cell infiltration and mitochondria-induced cardiomyocyte death during acute cardiac graft rejection.
Acute cardiac graft rejection (ACGR) is associated with cardiomyocyte apoptosis. We investigated the respective role of the Fas/FasL and mitochondrial permeability transition pore (mPTP) pathways in cardiomyocyte apoptosis accompanying ACGR. Heterotopic cardiac transplantations were performed in 7-9-week old C57BL6 or C3H mice. Wild type or Fas-deficient (lpr) mice underwent syngeneic (GS) or allogeneic (GA) transplantation, and received either saline or NIM811, a specific inhibitor of the mPTP. At day 5, we assessed ACGR by histology, cardiomyocyte apoptosis by caspase-3 activity and cytochrome c release, Ca(2+)-induced mPTP opening by a potentiometric approach, and expression of Fas, FasL, TNFalpha, perforin, granzyme using RT-PCR. Myocardial infiltration of CD8(+) T lymphocytes was performed by immunohistochemistry. Allogenic transplantation increased infiltration of inflammatory cells, upregulated FasL, perforin, granzyme, and TNFalpha, favored Ca(2+)-induced mPTP opening and increased caspase-3 activity and cytochrome c release in WT grafts. NIM811, but not Fas-deficiency, significantly reduced all these effects. NIM811 also limited infiltration of CD8(+) into WT and lpr transplants. These data suggest that the mPTP pathway plays a major role in cardiomyocyte apoptosis associated with ACGR. Inhibition of mPTP opening may attenuate cardiomyocyte apoptosis either directly or indirectly via a limitation of CD8(+) T-cell activation.
Gomez
L
L
INSERM E 0226, Université Claude Bernard Lyon I, Lyon, France.
Raisky
O
O
Chalabreysse
L
L
Verschelde
C
C
Bonnefoy-Berard
N
N
Ovize
M
M
D000208:Acute Disease; D000818:Animals; D016923:Cell Death; D004195:Disease Models, Animal; D018450:Disease Progression; D053222:Fas Ligand Protein; D015870:Gene Expression; D006084:Graft Rejection / Q000276:immunology / Q000378:metabolism / Q000473:pathology*; D016027:Heart Transplantation / Q000276:immunology*; D008297:Male; D008562:Membrane Glycoproteins / Q000235:genetics / Q000378:metabolism; D051379:Mice; D008809:Mice, Inbred C3H; D008810:Mice, Inbred C57BL; D008929:Mitochondria, Heart / Q000378:metabolism*; D032383:Myocytes, Cardiac / Q000473:pathology*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D018124:Receptors, Tumor Necrosis Factor / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013601:T-Lymphocytes / Q000276:immunology / Q000473:pathology*; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics / Q000378:metabolism; D048069:Tumor Necrosis Factors / Q000235:genetics / Q000378:metabolism; D019014:fas Receptor
D053222:Fas Ligand Protein; C491899:Fas protein, mouse; C505658:Fasl protein, mouse; D008562:Membrane Glycoproteins; D012333:RNA, Messenger; D018124:Receptors, Tumor Necrosis Factor; D014409:Tumor Necrosis Factor-alpha; D048069:Tumor Necrosis Factors; D019014:fas Receptor