Caveolin-1 Scaffolding Domain Peptides Attenuate The Inflammatory Response By Enhancing The Heme Oxygenase-1 Activity

Inhibition of HO-1 bioactivity by endogenous caveolin-1 (Cav-1) has been well characterized in vitro and in vivo. Cav-1 inhibits HO-1 bioactivity via the five-amino acid sequence (residues 97-101) between the caveolin scaffolding domain (CSD). We supposed that the CSD peptides might deprive of the endogenic inhibitory function of Cav-1 and therefore enhance HO-1 activity.In this study, primary alveolar macrophages from rat were isolated and cultured in vitro.The model of inflammatory cell injury induced by lipopolysaccharide (LPS). In the early stage, we used HO-1 agonist hemin and HO-1 activity inhibitor zinc protoporphyrin Ⅸ, and found that HO-1 has anti-inflammatory protection. In order to solve the problem of endogenous coherence of HO-1, we found two mutant peptides competitively bound to HO-1 by bioinformatics analysis. Wild-type (WT) CSD, truncated type (△101) CSD and mutant type (F99A) CSD were synthesized and applied in alveolar macrophage inflammation model.It was found that three kinds of peptides pretreatment significantly reduced the mRNA expression level of inflammatory cytokine, promoted alveolar macrophages polarization from M1 to M2 phenotype, altered HO-1 and Cav-1 protein expression and inhibit the degradation of cytoplasm IκB. Compared with the LPS group, the WT CSD and △101 CSD peptides decreased the combination of HO-1 and Cav-1, increased the HO-1 activity and reduced the phosphorylation level of the related proteins in the MAPK signaling pathway. While pretreatment with mutant type F99A CSD reduced the activity of HO-1. It can be seen from the results that wild-type WT CSD peptide have the most significant effect on increasing HO-1 activity.Mice intratracheal instilled LPS to establish the model of acute lung injury with pretreatment with wild-type WT CSD peptide. It was found that pretreatment with WT CSD could ameliorate the interstitial edema, alveolar disarray and neutrophil infiltration and reduce the expression of inflammatory cytokines in the lung tissue. Mechanistically, WT CSD peptide could decrease the co-localization of HO-1 and Cav-1 and increase the HO-1 activity.HO-1 activity inhibitor, zinc protoporphyrin Ⅸ, abolished the protective effect of WT CSD peptide on LPS-induced acute lung injury in mice, which implied the protective effect of WT CSD peptide was HO-1 dependent.In conclusion, CSD peptides have beneficial effects of anti-inflammation by restoring the HO-1 activity suppressed by Cav-1.