Skip to main page content
Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
, 103 (4), 724-732

Inhibition of Cyclin-dependent Kinase 2 Signaling Prevents Liver Ischemia and Reperfusion Injury

Affiliations

Inhibition of Cyclin-dependent Kinase 2 Signaling Prevents Liver Ischemia and Reperfusion Injury

Jin Xu et al. Transplantation.

Abstract

Background: Liver ischemia and reperfusion injury (IRI) is a major complication of liver transplant, hepatectomy, and hemorrhagic shock. The cyclin-dependent kinase 2 (CDK2) acts as a pivotal regulator of cell cycle and proliferation.

Methods: This study evaluated the modulation and therapeutic potential of CDK2 inhibition in a mouse model of partial liver warm IRI.

Results: Liver IR-triggered intrinsic CDK2 expression, peaking by 0.5 hour of reperfusion and maintaining a high-level throughout 1 to 24 hours. Roscovitine, a specific CDK2 inhibitor, prevented liver IR-mediated damage with abolished serum alanine aminotransferase levels and reserved liver pathology. CDK2 inhibition-mediated liver protection was accompanied by decreased macrophage/neutrophil infiltration, diminished hepatocyte apoptosis, abolished toll like receptor 4 signaling and downstream gene inductions (C-X-C motif ligand-10, Tumor necrosis factor-α, interleukin-1β, and interleukin-6), yet augmented interleukin-10 expression. In vitro, CDK2 inhibition by Roscovitine suppressed macrophage TLR4 activation and further depressed downstream inflammatory signaling (myeloid differentiation factor 88, interferon regulatory transcription factor 3, p38, c-Jun N-terminal kinase, and extracellular-regulated kinase).

Conclusions: Our novel findings revealed the critical role of CDK2 in hepatic cytoprotection and homeostasis against liver IRI. As CDK2 inhibition regulated local immune response and prevented hepatocyte death, this study provided the evidence for new treatment approaches to combat IRI in liver transplant.

Conflict of interest statement

Disclosure: The authors declare no conflicts of interest.

Figures

Figure 1.
Figure 1.
(a) Liver IRI–triggered CDK2 gene expression. Liver samples were retrieved from C57/B6 mice that were subjected to 90 min of warm ischemia, followed by different lengths of reperfusion. Sham-operated group as control (n = 6–8/group, *p < 0.05). (b) Dual staining of CD68 and CDK2 in liver subjected to 90 min of ischemia and 6 h of reperfusion (magnification x200, scale bar represents 100 μm). Livers in WT mice pretreated with Roscovitine or DMSO were subjected to 90 min of ischemia, followed by 6 h of reperfusion. The hepatocellular damage was assessed by (c) sALT levels and (d, e) liver histology (H&E staining: magnification x100 and x400, scale bar represents 100 μm) (n = 6–8/group, *p < 0.05).
Figure 2.
Figure 2.
Recruitment of neutrophils/macrophages in livers insulted by 90 min of ischemia and 6 h of reperfusion. (a) MPO levels (b) and (d) CD68+ macrophages (c) and (e) Ly-6G+ neutrophils in IR liver lobes (magnification x200, scale bar represents 100 μm) (n = 6–8/group, *p < 0.05).
Figure 3.
Figure 3.
Quantitative RT-PCR–measured cytokines/chemokines gene programs in livers subjected by 90 min of ischemia and 6 h of reperfusion. (a) CXCL-1 and CXCL-10; (b) TNF-α, IL-1β, and IL-6; and (c) IL-10. Values were normalized to HPRT gene induction (n = 6–8/group, *p < 0.05).
Figure 4.
Figure 4.
Apoptosis in livers insulted by 90 min of ischemia and 6h of reperfusion. (a) and (b) Caspase 3/7–assisted detection of hepatic apoptosis (white arrow) in ischemia liver lobes (magnification x200, scale bar represents 100 μm). (c) Western blots measured NF-κB, Bcl-2, and β-actin in liver samples (n = 4–6/group, *p < 0.05).
Figure 5.
Figure 5.
The effect of CDK2 inhibitor upon macrophage TLR4 activation in vitro. Bone marrow–derived macrophages were stimulated with LPS in the absence or presence of Roscovitine or DMSO (control). Gene inductions of (a) TLR4, (b) IL-10, and (c) TNF-α, IL-6, IFN-β in culture cells (n = 4–6/group, *p < 0.05).
Figure 6.
Figure 6.
The anti-inflammatory function of CDK2 inhibition upon macrophage in vitro. Bone marrow–derived macrophages were stimulated with LPS in the absence or presence of Roscovitine or DMSO (control). Roscovitine treatment depressed MyD88/IRF3 and MAPK signalings in macrophage. (a) MyD88 and IRF3; (b) TNF-α; (c) phosphorylated p38, phosphorylated JNK1/2, and phosphorylated ERK1/2 (*p < 0.05, n = 4–6/group).
Figure 7.
Figure 7.
A scheme of putative molecular mechanism by which CDK2 inhibition may depress TLR4 signaling and proinflammatory macrophage programs in liver IRI.

Similar articles

See all similar articles

Cited by 1 article

Publication types

Feedback