TSLP protects against liver I/R injury via activation of the PI3K/Akt pathway
Shilai Li, … , Patricia Loughran, Timothy R. Billiar
Shilai Li, … , Patricia Loughran, Timothy R. Billiar
Published November 14, 2019
Citation Information: JCI Insight. 2019;4(22):e129013. https://doi.org/10.1172/jci.insight.129013.
View: Text | PDF
Research Article Hepatology

TSLP protects against liver I/R injury via activation of the PI3K/Akt pathway

Abstract

Thymic stromal lymphopoietin (TSLP) is a cytokine mainly released by epithelial cells that plays important roles in inflammation, autoimmune disease, and cancer. While TSLP is expressed in the liver at high levels, the role of TSLP in liver ischemia/reperfusion (I/R) injury remains unknown. Experiments were carried out to determine the role of TSLP in liver I/R injury. Wild-type (WT) and TSLP receptor–knockout (TSLPR–/–) mice were subjected to liver partial warm I/R injury. Liver injury was assessed by measuring serum alanine aminotransferase (ALT) level, necrotic areas by liver histology, hepatocyte death, and local hepatic inflammatory responses. Signal pathways were explored in vivo and in vitro to identify possible mechanisms for TSLP in I/R injury. TSLP and TSLPR protein expression increased during liver I/R in vivo and following hepatocyte hypoxia/reoxygenation in vitro. Deletion of TSLPR or neutralization of TSLP with anti-TSLP antibody exacerbated liver injury in terms of serum ALT levels as well as necrotic areas in liver histology. Administration of exogenous recombinant mouse TSLP to WT mice significantly reduced liver damage compared with controls, but failed to prevent I/R injury in TSLPR–/– mice. TSLP induced autophagy in hepatocytes during liver I/R injury. Mechanistically, Akt was activated in WT mice during liver I/R injury. The opposite results were observed in TSLPR–/– mice. In addition, TSLP could directly induce Akt activation in hepatocytes independent of nonparenchymal cells in vitro. Furthermore, the Akt agonist, insulin-like growth factor-1 (IGF-1), prevented I/R injury in TSLPR–/– mice and an Akt inhibitor, LY294002, blocked the protective effects of TSLP in WT mice subjected to I/R. Our data indicate that TSLP protects against liver I/R injury via activation of the PI3K/Akt pathway. Through this pathway, TSLP induces autophagy in hepatocytes. Thus, TSLP is a potent inhibitor of stress-induced hepatocyte necrosis.

Authors

Shilai Li, Zhongjie Yi, Meihong Deng, Melanie J. Scott, Chenxuan Yang, Wenbo Li, Zhao Lei, Nicole M. Santerre, Patricia Loughran, Timothy R. Billiar

×

Figure 1

TSLP and TSLPR protein expression increase after liver I/R injury in vivo and H/R in vitro.

Options: View larger image (or click on image) Download as PowerPoint
TSLP and TSLPR protein expression increase after liver I/R injury in viv...
(A) TSLP and TSLPR protein expression in liver from WT mice in sham surgery (Sham) or ischemia/reperfusion (I/R; ischemia for 1 hour, reperfusion for 0, 1, 3, 6, 12, or 24 hours) groups were assessed with Western blot. GAPDH served as a loading control. (B) TSLP protein expression of WT and TSLPR–/– mice was assessed in liver (by Western blot) and serum (by ELISA, right) after liver I/R injury (I: 1 hour; R: 6 hours). All data are shown as the mean ± SEM. n = 5 in sham groups, n = 6 in liver I/R groups. NS, no significance. (C and D) TSLP and TSLPR protein expression in primary WT hepatocytes (C) and nonparenchymal cells (D) subjected to hypoxia for 10 hours (1% oxygen) and then reoxygenation for different time points (0, 2, 4, 6, 8, 10, and 12 hours) (H/R). (E) Primary WT hepatocytes (HC) and nonparenchymal cells (NPC) were cultured either in normal oxygen (control group) or in hypoxia for 10 hours (1% oxygen) and then reoxygenation for 8 hours (H/R group). TSLP protein levels in supernatant were assessed with Western blot. For Western blot results, figures are representative of data from multiple mice per experimental group or 3 independent in vitro experiments. ELISA data were assessed by unpaired, 2-tailed Student’s t test (B).