Cellular internalization of bystander nanomaterial induced by TAT-nanoparticles and regulated by extracellular cysteine

Abstract

Entry into cells is necessary for many nanomaterial applications, and a common solution is to functionalize nanoparticles (NPs) with cell-penetrating ligands. Despite intensive studies on these functionalized NPs, little is known about their effect on cellular activities to engulf other cargo from the nearby environment. Here, we use NPs functionalized with TAT (transactivator of transcription) peptide (T-NPs) as an example to investigate their impact on cellular uptake of bystander cargo. We find that T-NP internalization enables cellular uptake of bystander NPs, but not common fluid markers, through a receptor-dependent macropinocytosis pathway. Moreover, the activity of this bystander uptake is stimulated by cysteine presence in the surrounding solution. The cargo selectivity and cysteine regulation are further demonstrated ex vivo and in vivo. These findings reveal another mechanism for NP entry into cells and open up an avenue of studying the interplay among endocytosis, amino acids, and nanomaterial delivery.

Understanding nanoparticle endocytosis to improve targeting strategies in nanomedicine

“…8). 195,313 Shortly after TAT-peptide discovery, a homeoprotein penetratin of fruit fly Drosophila melanogaster has also been shown to have the ability for transporting therapeutic molecules across the cell membrane. 314 More than 100 peptides have been used since then to accelerate therapeutics delivery, such as siRNA, 315 antisense oligomers, 316 enzymes, 317 etc.…”

Simultaneous Exposure of Different Nanoparticles Influences Cell Uptake

“…In this context, an increase in uptake of both gold and iron oxide particles has been described when the two particles are exposed together to J774A.1 murine macrophages [37]. Similarly, it has been reported that uptake of a number of different nanoparticles increases when the nanoparticles are exposed to cells together with functionalised nanoparticles [38,39]. An increased uptake has also been described in vivo when nanoparticles are simultaneously administered with nanoparticles self-assembled from amphiphilic peptides [40].…”

Suitability of the In Vitro Cytokinesis-Block Micronucleus Test for Genotoxicity Assessment of TiO2 Nanoparticles on SH-SY5Y Cells

“…When nanomaterials are evaluated, this methodological procedure could cause a potential problem as Cyt-B also inhibits endocytosis processes-in which actin plays an essential role [44]-used by most cells to internalize nanomaterials [10,45]. Therefore, evaluating whether the presence of Cyt-B interferes with the cellular uptake of study NP is essential and very useful to interpret correctly the CBMN results obtained for these NP [6,[46][47][48][49]. In the present study, cellular uptake results confirmed an efficient dose-and time-dependent internalization of the TiO 2 NP by SH-SY5Y cells, regardless the Cyt-B concentration or its presence in the medium prior to the TiO 2 NP treatments.…”