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

• Published in: Nature communications Vol. 10; no. 1; pp. 3646 - 11
• Main Authors: Wei, Yushuang, Tang, Tang, Pang, Hong-Bo
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 13.08.2019; Nature Publishing Group; Nature Portfolio
• Subjects: 13; 13/1; 14; 14/19; 14/28; 631/61/2296; 631/61/350/354; 631/80/313/1461; Amino acids; Biological Transport; Cargo; Cell Line; Cysteine; Cysteine - metabolism; Endocytosis; Humanities and Social Sciences; Humans; Internalization; Ligands; multidisciplinary; Nanomaterials; Nanoparticles; Nanoparticles - metabolism; Science; Science (multidisciplinary); Selectivity; Trans-Activators - genetics; Trans-Activators - metabolism; Transcription
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-019-11631-w

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. To enter the cells, nanomaterials often need covalent conjugation with cell-penetrating ligands such as TAT. Here, the authors show that simple mixing with TAT-coupled nanoparticles enables the cellular uptake of unfunctionalized nanoparticles, and its activity is stimulated by cysteine in the medium.