DhHP-6 alleviates inflammation and reduces vascular permeability by eliminating reactive oxygen species.

Inflammation is a defensive immune response to external stimuli. However, uncontrolled inflammation may cause potential damage to the host. Therefore, timely control of uncontrolled inflammation is particularly important. Previous studies have found that small molecules with antioxidant activity, such as peroxidase mimic enzymes, can inhibit the development of inflammation. DhHP-6 is a new peptide mimic of peroxidase previously designed by our laboratory. Here, we explored its anti-inflammatory activity in vitro and in vivo. Our results showed that treatment with DhHP-6 significantly reduced the production of reactive oxygen species (ROS), NO, IL-6, and TNF-α in RAW264.7 cells induced by lipopolysaccharides (LPS); in addition, it also blocked the phosphorylation of extracellularly regulated kinase 1 and 2 (ERK1/2) and ribosomal s6 kinase 1 (RSK1), thereby blocking the phosphorylation and degradation of IκBα, and inhibiting the nuclear translocation of p65. Interestingly, treatment with DhHP-6 blocked the phosphorylation of ERK1/2 and myosin light chain kinase (MLCK) in HUVECs induced by LPS. Finally, we found that DhHP-6 treatment significantly reduced the infiltration of immune cells in balloon model rats. Therefore, we believe that DhHP-6 is a potent inhibitor of inflammation.