A peptide inhibitor of macrophage migration in atherosclerosis purified from the leech Whitmania pigra

Ethnopharmacological relevance: Atherosclerosis has become a worldwide public health problem that seriously threatens human health. Leech is traditional Chinese medicine that can be utilized to treat Cardiovascular Disease. Based on the anti-atherosclerosis activity of leech hydrolysate, we separated and purified the leech peptide capable of inhibiting macrophage migration and studied the pathways of the anti-migration leech peptide.

Materials and methods: The leech peptide capable of inhibiting macrophage migration that measured by cell migration assays from the leech Whitmania pigra was separated and purified by Q Sepharose FF strong alkaline anion exchange column chromatography, Superdex 30, Superdex peptide and G10 gel column chromatography. And the purity, molecular weight of the leech peptide was determined by high-performance liquid chromatography and high-resolution mass spectrometry. The pathways of anti-migration to macrophages of the leech peptide were studied by inhibitors, Western blotting and RT-PCR.

Results: We obtained a purified leech peptide with a sequence of EAGSAKELEGDPVAG from the leech Whitmania pigra. We also showed that the anti-migration to macrophages of the leech peptide was blocked by c-Jun N-terminal kinase (JNK) inhibitor and p38 mitogen-activated protein kinase (p38 MAPK) inhibitor. Moreover, the result of RT-PCR and Western blotting revealed that the leech peptide induced an increase in JNK, p38 phosphorylation and the transcription of mitogen-activated protein kinase kinase kinase 4 (MEKK4) and Apoptosis signal-regulating kinase 2 (ASK2). These data indicated that the anti-migration to macrophages of the leech peptide occurred through JNK and p38 MAPK pathways. In addition, the results demonstrated that the leech peptide had no significant effect on the immunological activity of macrophages including phagocytic ability, lysozyme activity, and levels of expression of inflammatory factors.

Conclusion: A sequence peptide was obtained from the hydrolysate of leech Whitmania pigra that inhibits macrophage migration.