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Updated: Aug 14, 2026
LPS and ATP-induced Death of PMA-differentiated THP-1 Macrophages and its Validation
Published on: May 3, 2024
LBP inhibitory peptide reduces endotoxin-induced macrophage activation and mortality
1Institute of Respiratory Disease, Xinqiao Hospital, Third Military Medical University, Chongqing, 400037, China.
Objective And Design:
The aim of this study was to investigate whether P12, a lipopolysaccharide (LPS)-binding protein (LBP) inhibitory peptide could reduce LPS induced inflammation in vitro and in vivo.
Material And Methods:
Human monocyte-like cell line (U937 cells) was grown in RPMI 1640 and stimulated with PMA in order to induce differentiation to the macrophage stage. A total of 70 Kunming mice (8-12 wk old) were used in our experiments. The effects of P12 on the binding of LPS to U937 cells and alveolar macrophages (AMs) were determined by flow cytometric analysis. Nuclear factor kappa B (NF-kappa B) translocation was evaluated with subunit P65 by Western blotting. The production of tumor necrosis factor-alpha (TNF-alpha), alanine transaminase (ALT), and nitric oxide (NO) as measured by ELISA, enzymatic activity assay, and enzymatic assay with nitrate reductase. Differences among groups were determined using one-way ANOVA test and Fisher exact test.
Treatment:
U937 cells were treated with LPS, LBP, and indicated concentrations of P12. Mice were administered LPS intraperitoneally and P12 via the tail vein.
Results:
P12 inhibited the binding of FITC-conjugated LPS (FITC-LPS) to U937 cells and AMs. NF-kappa B translocation and the production of TNF-alpha, ALT, and NO induced by LPS was also significantly suppressed by P12. Furthermore P12 protected mice from LPS-induced death.
Conclusions:
The results suggest that blockade of LBP at inflammation sites might attenuate LPS-induced circulatory shock. This results in a beneficial effect in a mouse model of endotoxemia.
Insights
The peptide P12 effectively reduced lipopolysaccharide (LPS)-induced inflammation by inhibiting LPS-binding protein (LBP) activity. This peptide demonstrated protective effects against endotoxemia in a mouse model.
Area of Science:
- Immunology
- Biochemistry
Background:
- Lipopolysaccharide (LPS) triggers potent inflammatory responses via Toll-like receptor 4 (TLR4).
- Lipopolysaccharide-binding protein (LBP) facilitates LPS interaction with TLR4, amplifying inflammation and potentially leading to sepsis or endotoxic shock.
Purpose of the Study:
- To evaluate the efficacy of P12, a novel LBP inhibitory peptide, in mitigating LPS-induced inflammation.
- To investigate the in vitro and in vivo effects of P12 on LPS binding, inflammatory signaling, and survival.
Main Methods:
- U937 human monocyte-like cells and murine alveolar macrophages were used to assess P12's inhibition of LPS binding via flow cytometry.
- Western blotting was employed to measure Nuclear Factor-kappa B (NF-kappa B) p65 translocation.
- Enzyme-linked immunosorbent assay (ELISA) and enzymatic assays quantified tumor necrosis factor-alpha (TNF-alpha), alanine transaminase (ALT), and nitric oxide (NO) production.
Main Results:
- P12 significantly inhibited the binding of LPS to both U937 cells and alveolar macrophages.
- P12 suppressed LPS-induced NF-kappa B p65 translocation, TNF-alpha, ALT, and NO production.
- Administration of P12 conferred protection against mortality in mice challenged with LPS.
Conclusions:
- P12 demonstrates potent anti-inflammatory properties by blocking LBP-mediated LPS activity.
- Targeting LBP with inhibitory peptides like P12 offers a promising therapeutic strategy for managing LPS-induced inflammatory conditions, including endotoxemia and circulatory shock.
