Premium
Identification of a Naturally‐occurring Heparin‐binding Peptide Preferentially Targeting the Nucleolus
Author(s) -
Loo Shining,
Kam Antony,
Tam James P
Publication year - 2019
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.2019.33.1_supplement.471.13
Subject(s) - nucleolus , intracellular , microbiology and biotechnology , peptide , chemistry , organelle , biochemistry , endocytosis , cell , flow cytometry , cytoplasm , biology
Organelle‐specific, cell‐penetrating peptides are useful for targeting intracellular proteins. Recent results showed that certain cationic cysteine‐rich peptides (CRPs) can target intracellular proteins, and hold promises for intracellular drug delivery [1]. Previously, we identified a family of CRPs, designated as bleogens, from Pereskia bleo , a medicinal paint found in South‐east Asia [2]. Our results showed that the prototypic bleogen pB1 is a heparin‐binding, anti‐microbial peptide with the potentials of intracellular targeting. Here we report that bleogen pB1 is an organelle‐specific cell‐penetrating peptide that targets the nucleolus. The linear precursor of bleogen pB1 was prepared using a stepwise solid‐phase synthesis and oxidative folded to its native state. We confirmed the purity and integrity of the synthetic bleogen pB1 using reversed‐phase high‐performance liquid chromatography, heparin‐affinity chromatography, and nuclear magnetic resonance spectroscopy. TAMRA‐pB1 was prepared using on‐resin TAMRA labeling at the N‐terminus of bleogen pB1. We demonstrated that TAMRA‐pB1 internalized into living cells via endocytosis using flow cytometry and live‐cell confocal microscopy. The cellular uptake of TAMRA‐pB1 was found to be dependent on glycosaminoglycan expressions. Upon cell entry, TAMRA‐pB1 preferentially targets the nucleus and eventually accumulates in the nucleolus. Taken together, this study highlights the discovery of bleogen pB1 as the first naturally‐occurring cell‐penetrating nucleolus‐targeting CRP. The ability of bleogen pB1 for specific delivery and accumulation of drugs in the nucleolus can be useful to address the problem of efflux‐mediated drug resistance encountered during cancer chemotherapy. Support or Funding Information This research was supported in part by Nanyang Technological University Internal Funding ‐ Synzymes and Natural Products (SYNC) and the AcRF Tier 3 funding (MOE2016‐T3‐1‐003). This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal .