Screening and identification of cardiac-specific peptides

Objective To screen cardiac-specific short-acting peptides on live myocardial slices using phage display technology, so as to improve the targeted delivery efficiency of drugs in myocardium and provide effective candidates for the targeted therapy of Duchenne muscular dystrophy (DMD) and other cardiomyopathies. Methods Myocardial tissue slices were prepared and cultured in vitro. The protein activities of the tissues were examined by immunohistochemistry. The in vitro cultured myocardial tissue slices were co-incubated with phage library (1×1012 pfu), and the phages that bound to the myocardium were recovered and amplified. The cardiac-specific targeting phages were identified by five rounds of in vitro phage biopanning. The candidate phage-related insertion sequence was sequenced, and the in vivo tissue distribution of the highly enriched phages was verified. Results A platform for in vitro culturing of live myocardial slices was established. Myocardial slices with good biological activity were obtained. After 48 hours of culturing, the normal expression and localization of Dystrophin protein were detected. Using phage library, candidate phages were screened after five rounds of phage biopanning. The results of the sequencing analyses and in vivo tissue distribution verification indicated that the selected candidate phages showed significant enrichment in myocardium and skeletal muscle, and showed low levels in liver and kidney tissues. Conclusions The candidate phages showed higher binding efficiency in both myocardium and skeletal muscle, indicating that the candidate peptides had myocardial targeting property, and that can provide a new method for myocardial targeting therapy of DMD. Key words: Duchenne muscular dystrophy; Phage display screening; Live myocardial slice; Cardiac-specific peptide