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Histidine-rich peptides for nanomedicine based drugs

Histidine-rich peptides are endosomal escape agents used in nanomedicine for drug delivery. The cellular endosomal uptake pathway is known as the rate-limiting barrier for bioactive molecules. Endosomal escape is known as the bottleneck in intracellular delivery. During drug delivery, many bioactive molecules get trapped in the endosomal compartment. Therefore effective strategies are needed to enhance endosomal escape and cytosolic bioavailability of therapeutic molecules.

Most uptake routes converge into endocytic vesicles. Both vesicle and cargo may be enzymatically degraded when late endosomes transform into lysosomes. The histidine's imidazole group has a pK of ~6 which gets protonated under acid conditions in the endosome—the positive charge recruits chloride ions (Cl-). The result is osmotic swelling and cracking of the endosome (according to the "proton sponge" model). The result is the cytoplasmic release of nanoparticles and the escape from lysosomal enzymes.

Histidine-rich peptides can be incorporated into polymers, liposomes, and proteins, including virus-like particles. However, poly-histidines are neutrally charged at neutral pH, minimizing nonspecific binding to serum proteins and inactivation of the particle.

Table 1:  Examples of Histidine-rich peptides used in nanomedicine as endosomolytic agents (Adapted from Ferrer-Miralles et al. 2011).

Type of construct

Tag sequence

Experimental model

# of His residues


pDNA/siRNA +peptide




In vitro, HepG2, COS 7, and CHO cells, 10X more expression than w/o histidine.


McKenzie DL, Smiley E, Kwok KY, Rice KG: Low molecular weight disulfide cross-linking peptides as nonviral gene delivery carriers. Bioconjug Chem 2000, 11:901-909. [PubMed]

pDNA + peptide +lactosylated polylysine

 Fusogenic peptide:

 H5WYG (23 aas;


In vitro, HepG2, B16 and Rb-1cells, 93-2150X more expression than control, with serum.


Midoux P, Kichler A, Boutin V, Maurizot JC, Monsigny M: Membrane permeabilization and efficient gene transfer by a peptide containing several histidines. Bioconjug Chem 1998, 9:260-267. [PubMed]

MS2 VLPs-peptide

 H5WYG (23 aas;


In Hep3B cells mediate endosomal escape that doesn’t occur without the peptide.


Ashley CE, Carnes EC, Phillips GK, Durfee PN, Buley MD, Lino CA, et al: Cellspecific delivery of diverse cargos by bacteriophage MS2 virus-like particles. ACS Nano 2011, 5:5729-5745. [Europe PMC]



CHO cells; increase expression 2-5 fold.



Moore NM, Sheppard CL, Barbour TR, Sakiyama-Elbert SE: The effect of endosomal escape peptides on in vitro gene delivery of polyethylene glycol-based vehicles. J Gene Med 2008, 10:1134-1149. [SEMATIC SCHOLAR]

Lipopeptide + pDNA


In vitro, COS 7 cells, similar results to PEI, lipofectamine


Tarwadi , Jazayeri JA, Prankerd RJ, Pouton CW: Preparation and in vitro evaluation of novel lipopeptide transfection agents for efficient gene delivery. Bioconjug Chem 2008, 19:940-950.  [PubMed]

pDNA + peptide

 LAH4 (26 aas;



In vitro, human hepatocarcinoma cells, 10× more expression

than lipofectamine.


Kichler A, Leborgne C, Danos O, Bechinger B: Characterization of the gene transfer process mediated by histidine-rich peptides. J Mol Med 2007, 85:191-201. [Springer Link]

Chitosan-CH + pDNA


 Chit. KH dendron

In vitro, HEK293 cells, increases expression up to 50-fold over chitosan alone.


Chang KL, Higuchi Y, Kawakami S, Yamashita F, Hashida M: Efficient gene transfection by histidine-modified chitosan through enhancement of endosomal escape. Bioconjug Chem 2010, 21:1087-1095. [Bioconjugate Chemistry]

Chit. 4 gen KH

dendron + pDNA


 Chit. KH dendron

Chitosan dendron improves escape over Chitosan-CH


Chang KL, Higuchi Y, Kawakami S, Yamashita F, Hashida M: Development of lysine-histidine dendron modified chitosan for improving transfection efficiency in HEK293 cells. J Control Release 2011, 156:195-202. [PubMed]

pDNA + peptide



In vitro, in U251, H4, T98G and C6 cell lines, up to 7000-fold improvement. In vivo, in rat intrastriatum injection.


Lo SL, Wang S: An endosomolytic Tat peptide produced by incorporation of histidine and cysteine residues as a nonviral vector for DNA transfection. Biomaterials 2008, 29:2408-2414. [PubMed]

FuGENE lipid+ peptide + pDNA


In vitro in 5 different cell lines, significant improvement over pDNA+ peptide alone.


Yamano S, Dai J, Yuvienco C, Khapli S, Moursi AM, Montclare JK: Modified Tat peptide with cationic lipids enhances gene transfection efficiency via temperature-dependent and caveolae-mediated endocytosis. J Control Release 2011, 152:278-285. [ScienceDirect]


 Polymer CM-PLH

In vitro, in HEK293 and B16-F10 cells, and in vivo, i.v. mice injection; higher transfection efficiency over PbAE alone.


Gu J, Wang X, Jiang X, Chen Y, Chen L, Fang X, et al: Self-assembled carboxy-methyl poly (l-histidine) coated poly (beta-amino ester)/DNA complexes for gene transfection. Biomaterials 2012, 33:644-658. [SEMANTIC SCHOLAR]




In vitro, COS-7 cells, improves lipofectamine levels of expression.


Tanaka K, Kanazawa T, Ogawa T, Suda Y, Takashima Y, Fukuda T, et al: A novel, bio-reducible gene vector containing arginine and histidine enhances gene transfection and expression of plasmid DNA. Chem Pharm Bull (Tokyo) 2011, 59:202-207. [PDF]


+ pDNA


In vitro, NIH 3T3, T-47D and COS-1 cells; expression is detected in 15-41% of cells, but not quantitated; no serum.


Hatefi A, Megeed Z, Ghandehari H: Recombinant polymer-protein fusion:a promising approach towards efficient and targeted gene delivery. J Gene Med 2006, 8:468-476. [ResearchGate]


Abbreviations: aas, amino acids; pDNA, plasmid DNA; PEI, poly (ethylene imine); Lau, lauryl; Pal, palmytoil; chit. 4 gen, chitosan 4 generation; CMPLH, carboxymethyl poly (L- histidine); PbAE, poly (b-amino ester); STR, staeroyl; FGF-2, fibroblast growth factor-2.



Behr JP. The Proton Sponge: a Trick to Enter Cells the Viruses Did Not Exploit. Chimia. 1997;51:34–36. []

Ferrer-Miralles N, Corchero JL, Kumar P, Cedano JA, Gupta KC, Villaverde A, Vazquez E. Biological activities of histidine-rich peptides; merging biotechnology and nanomedicine. Microb Cell Fact. 2011 Dec 2;10:101. [