The CPP Tat enhances eGFP cell internalization and transepithelial transport by the larval midgut of Bombyx mori (Lepidoptera, Bombycidae)

Dipartimento di Biologia, Università degli Studi di Milano, via Celoria 26, 20133 Milano, Italy.
Journal of insect physiology (Impact Factor: 2.47). 09/2011; 57(12):1689-97. DOI: 10.1016/j.jinsphys.2011.09.004
Source: PubMed


Cell-Penetrating Peptides (CPPs) are short peptides that are able to translocate across the cell membrane a wide range of cargoes. In the past decade, different mammalian cell lines have been used to clarify the mechanism of CPPs penetration and to characterize the internalization process, which has been described either as an energy-independent direct penetration through the plasma membrane, or as endocytic uptake. Whatever the mechanism involved, the cell penetration properties of these peptides make their use very attractive as vector for promoting the cellular uptake of coupled bioactive macromolecules, such as peptides, proteins and oligonucleotides. Here we demonstrate, for the first time in insect, that cultured columnar cells from the larval midgut of Bombyx mori more readily internalize eGFP (enhanced Green Fluorescent Protein) when fused to CPP Tat. Tat-eGFP translocates across the plasma membrane of absorptive cells in an energy-independent and non-endocytic manner, since no inhibition of the fusion protein uptake is exerted by metabolic inhibitors and by drugs that interfere with the endocytic uptake. Moreover, the CPP Tat enhances the internalization of eGFP in the columnar cells of intact midgut tissue, mounted in a suitable perfusion apparatus, and the transepithelial flux of the protein. These results open new perspectives for effective delivery of insecticidal macromolecules targeting receptors located both within the insect gut epithelium and behind the gut barrier, in the hemocoel compartment.

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    • "It was demonstrated that CPP Tat fused to enhanced Green Fluorescent Protein facilitates its internalization and transepithelial transport into the columnar cells from intact larval midgut tissue of Bombyx miori (Lepidoptera: Bombycidae). These results offer the possibility of effective oral delivery of bioinsecticidal molecules to targets located both within the insect gut epithelium and behind the gut barrier, in the hemocoel compartment, provided cargo molecules selectively acting on the pest species to be controlled are available [14]. During the ensuing decades, a vast number of CPPs and other similar cytolytic and membrane-acting peptides have been discovered and their mechanisms of action examined [1,15]. "
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