Syk/BLNK/NF-κB signaling promotes pancreatic injury induced by tacrolimus and potential protective effect from rapamycin.

BACKGROUND: The treatment of tacrolimus-induced post-transplantation diabetes mellitus (PTDM) has become a hot topic to improve the long-term survival of organ transplant patients, however whose pathogenesis has not been fully elucidated. In pancreas, the up-regulation of NF-κB has been reported to stimulate cytokine IL-1β/TNF-α secretion, inducing pancreatic injury, meanwhile other studies have reported the inhibitory effect of rapamycin on NF-κB.

PURPOSE: The aim of this study was to clarify the mechanism of tacrolimus-induced pancreatic injury and to explore the potential effect from small dose of sirolimus.

METHODS: Wistar rats were randomly divided normal control (NC) group, PTDM group, sirolimus intervention (SIR) group. Transcriptomic analysis was used to screen potential mechanism of PTDM. Biochemical index detections were used to test the indicators of pancreatic injury. Pathological staining, immumohistochemical staining, immunofluorescent staining, western blot were used to verify the underlying mechanism.

RESULTS: Compared with NC group, the level of insulin was significant reduction (P < 0.01), inversely the level of glucagon was significantly increase (P < 0.01) in PTDM group. Transcriptomic analysis indicated Syk/BLNK/NF-κB signaling was significantly up-regulated in PTDM group. Pathological staining, immumohistochemical staining, immunofluorescent staining, western blot verified Syk/BLNK/NF-κB and TNF-α/IL-1β were all significantly increased (P < 0.05 or P < 0.01), demonstrating the mechanism of tacrolimus-induced pancreatic injury via Syk/BLNK/NF-κB signaling. In addition, compared with PTDM group, the levels of weight, FPG, AMY, and GSP in SIR group were significant ameliorative (P < 0.05 or P < 0.01), and the expressions of p-NF-κB, TNF-α/IL-1β in SIR group were significantly reduction (P < 0.05 or P < 0.01), showing Syk/BLNK/NF-κB signaling promoted pancreatic injury induced by tacrolimus and potential protective effect from rapamycin reducing NF-κB.

CONCLUSION: Syk/BLNK/NF-κB signaling promotes pancreatic injury induced by tacrolimus and rapamycin has a potentially protective effect by down-regulating NF-κB. Further validation and clinical studies are needed in the future.