Activation of c-Jun NH2-terminal kinase (JNK) pathway during islet transplantation and prevention of islet graft loss by intraportal injection of JNK inhibitor.
OBJECTIVE
Although application of the Edmonton protocol has markedly improved the outcome for pancreatic islet transplantation, the insulin independence rate after islet transplantation from one donor pancreas has remained low. During the isolation process and subsequent clinical transplantation, islets are subjected to severe adverse conditions that impair survival and ultimately contribute to graft failure. The aim of this study was to map the c-Jun NH2-terminal kinase (JNK) pathway that mediates islet loss during islet transplantation and to clarify whether intraportal injection with JNK inhibitor during islet transplantation can prevent islet graft loss.


METHODS
We measured JNK activity in the liver, fat and muscle of diabetic mice and in the liver immediately after islet transplantation. We examined the effect of intraportal injection of JNK inhibitory peptide at islet transplantation.


RESULTS
JNK activity became progressively higher at least until 24 h after transplantation. The cell-permeable peptide of JNK inhibitor was delivered not only in the liver but also in other insulin target organs, preventing JNK activation in the liver at least until 24 h after transplantation and reducing JNK activity in these insulin target organs. Moreover, the peptide inhibitor prevented islet graft loss immediately after transplantation and improved islet transplant outcome.


CONCLUSIONS
These findings suggest that control of the JNK pathway is extremely important in islet transplantation and that intraportal injection of JNK inhibitor during islet transplantation (addition of JNK inhibitor to transplant media) could prevent the impairment of islet cells, leading to improved outcome for pancreatic islet transplantation.
Noguchi
H
H
Diabetes Research Institute Japan, Aichi, Japan. noguchih@med.nagoya-u.ac.jp
Nakai
Y
Y
Ueda
M
M
Masui
Y
Y
Futaki
S
S
Kobayashi
N
N
Hayashi
S
S
Matsumoto
S
S
D000273:Adipose Tissue / Q000201:enzymology; D000818:Animals; D001786:Blood Glucose / Q000378:metabolism; D003921:Diabetes Mellitus, Experimental / Q000097:blood / Q000601:surgery; D004789:Enzyme Activation; D004791:Enzyme Inhibitors / Q000627:therapeutic use*; D005951:Glucose Tolerance Test; D006085:Graft Survival / Q000187:drug effects / Q000502:physiology*; D016381:Islets of Langerhans Transplantation / Q000502:physiology*; D048031:JNK Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D008099:Liver / Q000201:enzymology; D051379:Mice; D008807:Mice, Inbred BALB C; D018482:Muscle, Skeletal / Q000201:enzymology
D001786:Blood Glucose; D004791:Enzyme Inhibitors; D048031:JNK Mitogen-Activated Protein Kinases