Tumor necrosis factor receptors support murine hematopoietic progenitor function in the early stages of engraftment.
Tumor necrosis factor (TNF) family receptors/ligands are important participants in hematopoietic homeostasis, in particular as essential negative expansion regulators of differentiated clones. As a prominent injury cytokine, TNF-alpha has been traditionally considered to suppress donor hematopoietic stem and progenitor cell function after transplantation. We monitored the involvement of TNF receptors (TNF-R) 1 and 2 in murine hematopoietic cell engraftment and their inter-relationship with Fas. Transplantation of lineage-negative (lin(-)) bone marrow cells (BMC) from TNF receptor-deficient mice into wild-type recipients showed defective early engraftment and loss of durable hematopoietic contribution upon recovery of host hematopoiesis. Consistently, cells deficient in TNF receptors had reduced competitive capacity as compared to wild-type progenitors. The TNF receptors were acutely upregulated in bone marrow (BM)-homed donor cells (wild-type) early after transplantation, being expressed in 60%-75% of the donor cells after 6 days. Both TNF receptors were detected in fast cycling, early differentiating progenitors, and were ubiquitously expressed in the most primitive progenitors with long-term reconstituting potential (lin(-)c-kit(+) stem cell antigen (SCA)-1(+)). BM-homed donor cells were insensitive to apoptosis induced by TNF-alpha and Fas-ligand and their combination, despite reciprocal inductive cross talk between the TNF and Fas receptors. The engraftment supporting effect of TNF-alpha is attributed to stimulation of progenitors through TNF-R1, which involves activation of the caspase cascade. This stimulatory effect was not observed for TNF-R2, and this receptor did not assume redundant stimulatory function in TNFR1-deficient cells. It is concluded that TNF-alpha plays a tropic role early after transplantation, which is essential to successful progenitor engraftment.
Pearl-Yafe
Michal
M
Frankel Laboratory, Center for Stem Cell Research, Schneider Children's Medical Center of Israel, Petach Tikva, Israel.
Mizrahi
Keren
K
Stein
Jerry
J
Yolcu
Esma S
ES
Kaplan
Ofer
O
Shirwan
Haval
H
Yaniv
Isaac
I
Askenasy
Nadir
N
D000818:Animals; D017209:Apoptosis; D002478:Cells, Cultured; D006412:Hematopoietic Stem Cells / Q000166:cytology / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D047888:Receptors, Tumor Necrosis Factor, Type I / Q000172:deficiency / Q000378:metabolism*; D047889:Receptors, Tumor Necrosis Factor, Type II / Q000172:deficiency / Q000378:metabolism*
D047888:Receptors, Tumor Necrosis Factor, Type I; D047889:Receptors, Tumor Necrosis Factor, Type II; C506236:Tnfrsf1a protein, mouse