2′-Fluoro-Pyrimidine-Modified RNA Aptamers Specific for Lipopolysaccharide Binding Protein (LBP)

Abstract

Lipopolysaccaride binding protein (LBP), a glycosylated acute phase protein, plays an important role in the pathophysiology of sepsis. LBP binds with high affinity to the lipid part of bacterial lipopolysaccaride (LPS). Inhibition of the LPS-LBP interaction or blockage of LBP-mediated transfer of LPS monomers to CD14 may be therapeutical strategies to prevent septic shock. LBP is also of interest as a biomarker to identify septic patients at high risk for death, as LBP levels are elevated during early stages of severe sepsis. As a first step toward such potential applications, we isolated aptamers specific for murine LBP (mLBP) by in vitro selection from a library containing a 60-nucleotide randomized region. Modified RNA pools were transcribed in the presence of 2′-fluoro-modified pyrimidine nucleotides to stabilize transcripts against nuclease degradation. As verified for one aptamer experimentally, the selected aptamers adopt a “three-helix junction” architecture, presenting single-stranded 7-nt (5′-YGCTTCY) or 6-nt (5′-RTTTCY) consensus sequences in their core. The best binder (aptamer A011; Kd of 270 nM for binding to mLBP), characterized in more detail by structure probing and boundary analysis, was demonstrated to bind with high specificity to murine LBP.

Tumor-Specific Delivery of 5-Fluorouracil–Incorporated Epidermal Growth Factor Receptor–Targeted Aptamers as an Efficient Treatment in Pancreatic Ductal Adenocarcinoma Models

“…However, ribose modifications such as 2 0 -deoxy or 2 0 -amino, 2 0 -fluoro confer resistance to ribonucleases. 46 Moreover, nucleobase modifications, such as 5-fluoro, impart protection against ribonucleases. 47 We synthesized 2 0 dFC-modified 5FU-EGFR aptamers and monitored their influence on tumor growth in vivo.…”

Proteomic Analysis Revealed the Characteristics of Key Proteins Involved in the Regulation of Inflammatory Response, Leukocyte Transendothelial Migration, Phagocytosis, and Immune Process during Early Lung Blast Injury

“…Lbp can act as a lipid transfer protein to transfer LPS to the CD14/TLR4 receptor complex on immune cells, thereby enhancing the immune response to LPS [ 46 ]. It has been reported that high levels of Lbp in the serum of septic patients attenuated the inflammatory response of macrophages and monocytes to LPS [ 47 ]. In addition to systemic infection, infectious and allergic lung inflammation can also lead to increased serum Lbp levels [ 48 ].…”

GAB1 alleviates septic lung injury by inhibiting the TLR4/ NF‐κB pathway

“…LPS binds to lipopolysaccharide binding protein (LBP), and LBP can promote the binding of LPS and CD14 to form LPS/LBP/CD14 complex. 31 The LPS/LBP/CD14 complex binds to TLR4 and finally stimulates the production of NF-κB and activating protein 1 (Activated Protein 1) and interferon regulatory factor (IRF), which in turn promotes the release of pro-inflammatory cytokines TNFα, IL-1β and IL-6. 32,33 Previous studies have found that the TLR4/NF-κB pathway is widely involved in LPS-induced lung injury.…”