Pivotal Advance: Up-regulation of acetylcholine synthesis and paracrine cholinergic signaling in intravascular transplant leukocytes during rejection of rat renal allografts.
During acute rejection, large numbers of leukocytes accumulate in the blood vessels of experimental renal allografts. About 70% of them are activated, cytotoxic monocytes that appear to be involved in allograft destruction. ACh exerts anti-inflammatory effects upon monocytes/macrophages and has been proposed to be a key player in neuroimmunological interactions. Its short half-life, however, makes it unlikely that neuronal ACh affects blood leukocytes. Renal transplantation was performed in the allogeneic DA to LEW and in the isogeneic LEW to LEW rat strain combination. Intravascular leukocytes were harvested after 4 days, and the expression of CHT1, cChAT, pChAT, and nAChR subunits was investigated by RT-PCR, immunoblotting, and immunohistochemistry. Monocytes were identified by double-labeling with ED1-antibody, directed to a CD68-like antigen. ACh content was measured by HPLC. [Ca(2+)](i) was monitored by Fura-2. Intravascular graft leukocytes express CHT1 and cChAT mRNA and protein and pChAT protein. Their expression is strongly up-regulated in vivo during acute allograft rejection. Immunohistochemistry revealed CHT1, cChAT, and pChAT protein in ED1-positive monocytes. The ACh content of allograft intravascular leukocytes was sixfold higher than that of isografts. Intravascular leukocytes express nAChR subunits, and an ATP-induced increase in [Ca(2+)](i) was augmented in vitro by a nAChR inhibitor in allograft but not isograft leukocytes. Intravascular graft leukocytes, among them monocytes, up-regulate non-neuronal ACh synthesis and develop auto-/paracrine cholinergic attenuation of ATP signaling during acute allograft rejection.
Hecker
Andreas
A
Department of General and Thoracic Surgery, Justus-Liebig-University Giessen, Giessen, Germany.
Mikulski
Zbigniew
Z
Lips
Katrin S
KS
Pfeil
Uwe
U
Zakrzewicz
Anna
A
Wilker
Sigrid
S
Hartmann
Petra
P
Padberg
Winfried
W
Wessler
Ignaz
I
Kummer
Wolfgang
W
Grau
Veronika
V
D000109:Acetylcholine / Q000096:biosynthesis*; D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D027682:Cation Transport Proteins / Q000032:analysis / Q000235:genetics; D006084:Graft Rejection / Q000276:immunology*; D016030:Kidney Transplantation / Q000009:adverse effects* / Q000276:immunology; D008214:Lymphocytes / Q000473:pathology*; D019899:Paracrine Communication; D051381:Rats; D011917:Rats, Inbred Lew; D011978:Receptors, Nicotinic / Q000032:analysis / Q000235:genetics; D015398:Signal Transduction; D014184:Transplantation, Homologous; D014185:Transplantation, Isogeneic; D015854:Up-Regulation
C501512:CHT1 protein, rat; D027682:Cation Transport Proteins; D011978:Receptors, Nicotinic; D000255:Adenosine Triphosphate; D000109:Acetylcholine