Tumor necrosis factor-alpha receptor p75 is required in ischemia-induced neovascularization.
BACKGROUND
Aging is a risk factor for coronary and peripheral artery disease. Tumor necrosis factor-alpha (TNF-alpha), a proinflammatory cytokine, is expressed in ischemic tissue and is known to modulate angiogenesis. Little is known about the role of TNF-alpha receptors (TNFR1/p55 and TNFR2/p75) in angiogenic signaling.


RESULTS
We studied neovascularization in the hindlimb ischemia model in young and old TNFR2/p75 knockout (p75KO) and wild-type age-matched controls. Between days 7 to 10 after hindlimb surgery, 100% of old p75KOs experienced autoamputation of the operated limbs, whereas none of the age-matched wild-type mice exhibited hindlimb necrosis. Poor blood flow recovery in p75KO mice was associated with increased endothelial cell apoptosis, decreased capillary density, and significant reductions in the expression of vascular endothelial growth factor and basic fibroblast growth factor-2 mRNA transcripts in ischemic tissue and in circulating endothelial progenitor cells. The number of circulating bone marrow-derived endothelial progenitor cells was significantly reduced in p75KO mice. Transplantation of wild-type bone marrow mononuclear cells into irradiated old p75KO mice 1 month before hindlimb surgery prevented limb loss.


CONCLUSIONS
Our present study suggests that ischemia-induced endothelial progenitor cell-mediated neovascularization is dependent, at least in part, on p75 TNF receptor expressed in bone marrow-derived cells. Specifically, endothelial cell/endothelial progenitor cell survival, vascular endothelial growth factor expression, endothelial progenitor cell mobilization from bone marrow, endothelial progenitor cell differentiation, and ultimately ischemia-induced collateral vessel development are dependent on signaling through TNFR2/p75. Furthermore, because TNFR2/p75 becomes an age-related limiting factor in postischemic recovery, it may be a potential gene target for therapeutic interventions in adult vascular diseases.
Goukassian
David A
DA
Division of Cardiovascular Diseases, Department of Medicine, Caritas St Elizabeth's Medical Center, Boston, Mass, USA. dgoukass@bu.edu
Qin
Gangjian
G
Dolan
Christine
C
Murayama
Toshinori
T
Silver
Marcy
M
Curry
Cynthia
C
Eaton
Elizabeth
E
Luedemann
Corinne
C
Ma
Hong
H
Asahara
Takayuki
T
Zak
Victor
V
Mehta
Shanu
S
Burg
Aaron
A
Thorne
Tina
T
Kishore
Raj
R
Losordo
Douglas W
DW
D000375:Aging / Q000502:physiology; D000818:Animals; D017209:Apoptosis; D016026:Bone Marrow Transplantation; D002478:Cells, Cultured; D042783:Endothelial Cells / Q000473:pathology; D006614:Hindlimb / Q000098:blood supply; D007511:Ischemia / Q000503:physiopathology*; D051379:Mice; D018345:Mice, Knockout; D016328:NF-kappa B / Q000378:metabolism; D018919:Neovascularization, Physiologic; D011401:Promoter Regions, Genetic; D012333:RNA, Messenger / Q000032:analysis; D047889:Receptors, Tumor Necrosis Factor, Type II / Q000502:physiology*; D015398:Signal Transduction; D013234:Stem Cells / Q000502:physiology; D042461:Vascular Endothelial Growth Factor A / Q000235:genetics
D016328:NF-kappa B; D012333:RNA, Messenger; D047889:Receptors, Tumor Necrosis Factor, Type II; D042461:Vascular Endothelial Growth Factor A