Linagliptin Inhibits Lipopolysaccharide-Induced Inflammation Concentration-Dependently And -Independently

Area of Science:

• Immunology
• Pharmacology

Background:

• Dipeptidyl peptidase-4 (DPP-4) inhibitors, including linagliptin, are known to possess anti-inflammatory properties.
• The precise in vitro mechanisms of linagliptin's anti-inflammatory effects, particularly in the context of lipopolysaccharide (LPS)-induced inflammation and the role of LPS-binding protein (LBP), require further elucidation.

Purpose of the Study:

• To investigate the anti-inflammatory mechanisms of linagliptin in an experimental model involving LPS and LPS-binding protein (LBP).
• To determine whether linagliptin's anti-inflammatory effects are concentration-dependent in LPS-induced inflammation.

Main Methods:

• Human U937 monocytes were differentiated into macrophages and treated with varying concentrations of linagliptin.
• Cells were subsequently stimulated with LPS in the presence or absence of linagliptin.
• Levels of interleukin-6 (IL-6), LBP, nuclear factor-kappa B (NF-κB)/p65, and reactive oxygen species (ROS) were measured.

Main Results:

• Linagliptin significantly inhibited LPS-induced IL-6 production and NF-κB/p65 activation in a concentration-dependent manner.
• LPS-induced ROS levels were reduced by linagliptin across all tested concentrations.
• LBP levels were not affected by linagliptin or LPS treatment.

Conclusions:

• Linagliptin exhibits both concentration-dependent and -independent anti-inflammatory effects against LPS-induced pro-inflammatory responses.
• These findings suggest that linagliptin employs both Toll-like receptor 4 (TLR4)-dependent and -independent mechanisms to suppress inflammation.