Ex vivo transfer of nuclear factor-kappaB decoy ameliorates hepatic cold ischemia/reperfusion injury

Liver protection strategies in liver transplantation

BACKGROUND

Liver transplantation is the therapy of choice for patients with end-stage liver diseases. However, the gap between the low availability of organs and high demand is continuously increasing. Innovative strategies for organ protection are necessary to expand donor pool and to achieve better outcomes for liver transplantation. The present review analyzed and compared various strategies of liver protection.

DATA SOURCES

Databases such as PubMed, Embase and Ovid were searched for the literature related to donor liver protection strategies using following key words: "ischemia reperfusion injury", "graft preservation", "liver transplantation", "machine perfusion" and "conditioning". Of the 146 studies identified, only those with cutting edge strategies were analyzed.

RESULTS

A variety of therapeutic approaches were proposed to alleviate graft ischemia/reperfusion injury, which included static cold storage, machine perfusion (hypothermic, normothermic and subnormothermic), manual conditioning (pre, post and remote), and pharmacological conditioning. Evidences from animal experiments and clinical trials suggested that all these strategies could potentially protect liver graft; however, their clinical applications are limited partially due to their own disadvantages.

CONCLUSIONS

There are a plenty of methods suggested to decrease the degree of donor liver transplantation-related injury. However, none of these approaches is perfect in clinical practice. More translational researches (molecular and clinical studies) are needed to improve the techniques in liver graft protection.

Potential protective effect of nuclear factor-κB decoy oligodeoxynucleotides on endotoxin-induced liver injury

PURPOSE

We sought to study the protective effects of nuclear factor-κB decoy oligodeoxynucleotides (ODNs) on endotoxin-induced liver injury in a rat model.

METHODS

Sixty Sprague-Dawley rats were randomly divided into a control (n=20), a lipopolysaccharide (LPS) (n=20), and an NF-κB decoy ODN group (n=20). Liver and blood serum samples were collected at 24 hours after the operation. NF-κB binding activity was detected by an electrophoretic mobility shift assay, liver histopathology, by light microscopy; and cell apoptosis, by a terminal-deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end-labeling assay. The serum of liver enzyme (aspartate transaminase [AST]) levels were measured using an automated biochemical analyzer and tumor necrosis factor (TNF)-α and interleukin (IL)-6 by enzyme-linked immunosorbent assays.

RESULTS

NF-κB was dramatically activated after endotoxin-induced liver injury. Many hepatocytes underwent degeneration and necrosis in the LPS group. The expressions of AST, TNF-α, and IL-6 were significantly increased compared with the control group (P=.0005), However, NF-κB decoy ODNs altered these undesirable changes. On the other hand, IL-6 expression was not significantly decreased by the NF-κB decoy versus the LPS group (P=.0745).

CONCLUSIONS

NF-κB decoy strategy inhibited the binding activity of NF-κB, thus suppressing production of downstream cytokines which play crucial roles in protection from endotoxin-induced injury.

Recent patents on therapeutic applications of the transcription factor decoy approach

INTRODUCTION

Transcription is considered as an important target of drugs employed in biomedicine. Therefore, novel strategies to inhibit the biological effects of transcription factors (TFs) are of interest, such as targeting promoters with triple-helix-forming oligonucleotides and antisense targeting of mRNAs coding for TFs.

AREAS COVERED

The objective of this review is to describe studies considering inhibition of TF functions with molecules mimicking TF binding sites (transcription factor decoy approach, TFD) and to summarize the patents on possible clinical applications of this approach.

EXPERT OPINION

Treatment of cells with TFD molecules leads to inhibition (or activation) of genes regulated by the target transcription factors. The studies and patents on this specific issue have taken in great consideration the delivery strategy, which is a very important parameter. The TFD strategy has been proven effective in vivo. The stability of the TFD molecules in vivo should be carefully considered, as well as the possible toxicity and/or possible effects on innate and adaptive immune response. In order to improve clinical parameters, many patents suggest the use of the TFD molecules in combination with drugs already employed in therapy. We are expecting in the near future relevant clinical trials based on the TFD strategy.

Decoy oligodeoxyribonucleotides and peptide nucleic acids-DNA chimeras targeting nuclear factor kappa-B: inhibition of IL-8 gene expression in cystic fibrosis cells infected with Pseudomonas aeruginosa

Cystic fibrosis (CF) is characterized by a deep inflammatory process, with production and release of cytokines and chemokines, among which interleukin 8 (IL-8) represents one of the most important. Accordingly, there is a growing interest in developing therapies against IL-8, with the aim of reducing the excessive inflammatory response in the airways of CF patients. Since transcription factor NF-kappaB plays a critical role in IL-8 expression, the transcription factor decoy (TFD) strategy might be of interest. TFD is based on biomolecules mimicking the target sites of transcription factors (TFs) and able to interfere with TF activity when delivered to target cells. Here, we review the inhibitory effects of decoy oligodeoxyribonucleotides (ODNs) on expression of IL-8 gene and secretion of IL-8 by cystic fibrosis cells infected by Pseudomonas aeruginosa. In addition, the effects of decoy molecules based on peptide nucleic acids (PNAs) are discussed. In this respect PNA-DNA-PNA (PDP) chimeras are interesting: (a) unlike PNAs, they can be complexed with liposomes and microspheres; (b) unlike oligodeoxyribonucleotides (ODNs), they are resistant to DNAses, serum and cytoplasmic extracts; (c) unlike PNA/PNA and PNA/DNA hybrids, they are potent decoy molecules. Interestingly, PDP/PDP NF-kappaB decoy chimeras inhibit accumulation of pro-inflammatory mRNAs (including IL-8 mRNA) in P. aeruginosa infected IB3-1, cells reproducing the effects of decoy oligonucleotides. The effects of PDP/PDP chimeras, unlike ODN-based decoys, are observed even in absence of protection with lipofectamine. Since IL-8 is pivotal in pro-inflammatory processes affecting cystic fibrosis, inhibition of its functions might have a clinical relevance.