Development of a novel RANKL-based peptide, microglial healing peptide1-AcN (MHP1-AcN), for treatment of ischemic stroke

• Published in: Scientific reports Vol. 8; no. 1; pp. 17770 - 10
• Main Authors: Shimamura, Munehisa, Nakagami, Hironori, Shimizu, Hideo, Mukai, Hideyuki, Watanabe, Ryosuke, Okuzono, Takeshi, Kawano, Tomohiro, Ikeda, Yuka, Hayashi, Hiroki, Yoshida, Shota, Ju, Nan, Mochizuki, Hideki, Morishita, Ryuichi
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 11-12-2018; Nature Publishing Group
• Subjects: 13; 13/21; 631/250/256/2516; 631/378/1689/534; 64/60; 82; 82/58; 82/75; Acetylation; Amino Acid Sequence; Animals; Brain Ischemia - drug therapy; Cardiovascular system; Clinical trials; Fibrinolytic Agents - therapeutic use; Hemorrhage; High-performance liquid chromatography; Humanities and Social Sciences; Inflammation; Ischemia; Liquid chromatography; Male; Mice; Mice, Inbred ICR; Microglia - physiology; multidisciplinary; Peptides; Peptides - therapeutic use; RANK Ligand - therapeutic use; Science; Science (multidisciplinary); Stroke; Stroke - therapy; t-Plasminogen activator; Thrombolysis; Tissue Plasminogen Activator - administration & dosage; Toll-like receptors; TRANCE protein; Monofilament Surgical Suture; Suppressed TLR4 Signaling; High-performance Liquid Chromatography Mass Spectrometry (HPLC/MS); Middle Cerebral Artery Occlusion Procedure; Continuous Subcutaneous Injection
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/s41598-018-35898-z

Although the regulation of post-ischemic inflammation is an important strategy to treat ischemic stroke, all clinical trials have failed to show its efficacy. To solve the problem, we previously developed a novel partial peptide of RANKL, microglial healing peptide 1 (MHP1), which could reduce ischemic injury by inhibiting Toll-like receptor (TLR) induced inflammation. However, optimization of the peptide was necessary to increase the stability and efficacies for clinical use. According to information gathered through HPLC/MS in serum, we have newly designed a series of modified MHP1 peptides and have found that N-terminal acetylation and C-terminal amidation in MHP1 (MHP1-AcN), can strengthen its anti-inflammatory effects and increase its stability with anti-osteoclastogenic effects. Anti-TLR activity was reported to be reduced in MHP1 when incubated at 37 °C for 24 hrs, but MHP1-AcN could keep the activity under the same condition. The therapeutic effect of MHP1-AcN was observed in transient ischemic stroke model at lower dose than MHP1. Importantly, MHP1-AcN did not affect thrombolytic effects of tissue plasminogen activator (tPA) and inhibited tPA-induced hemorrhagic transformation. These findings indicated that MHP1-AcN was stable and effective anti-TLR signal peptide and could be a promising agent for treating stroke patients receiving tPA and endovascular therapy.