Poly-lactic acid nanoparticles (PLA-NP) promote physiological modifications in lung epithelial cells and are internalized by clathrin-coated pits and lipid rafts

Camila Macedo Luz, Matthew S. P. Boyles, Priscila Falagan-Lotsch, Mariana Rodrigues Pereira, Henrique Rudolf Tutumi, Eidy Oliveira Santos, Nathalia Balthazar Martins, Martin Himly, Aniela Sommer, Ilse Foissner, Albert Duschl, José Mauro Granjeiro, Paulo Emílio Corrêa Leite*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

56 Citations (Scopus)
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Background: Poly-lactic acid nanoparticles (PLA-NP) are a type of polymeric NP, frequently used as nanomedicines, which have advantages over metallic NP such as the ability to maintain therapeutic drug levels for sustained periods of time. Despite PLA-NP being considered biocompatible, data concerning alterations in cellular physiology are scarce. Methods: We conducted an extensive evaluation of PLA-NP biocompatibility in human lung epithelial A549 cells using high throughput screening and more complex methodologies. These included measurements of cytotoxicity, cell viability, immunomodulatory potential, and effects upon the cells' proteome. We used non- and green-fluorescent PLA-NP with 63 and 66 nm diameters, respectively. Cells were exposed with concentrations of 2, 20, 100 and 200 μg/mL, for 24, 48 and 72 h, in most experiments. Moreover, possible endocytic mechanisms of internalization of PLA-NP were investigated, such as those involving caveolae, lipid rafts, macropinocytosis and clathrin-coated pits. Results: Cell viability and proliferation were not altered in response to PLA-NP. Multiplex analysis of secreted mediators revealed a low-level reduction of IL-12p70 and vascular epidermal growth factor (VEGF) in response to PLA-NP, while all other mediators assessed were unaffected. However, changes to the cells' proteome were observed in response to PLA-NP, and, additionally, the cellular stress marker miR155 was found to reduce. In dual exposures of staurosporine (STS) with PLA-NP, PLA-NP enhanced susceptibility to STS-induced cell death. Finally, PLA-NP were rapidly internalized in association with clathrin-coated pits, and, to a lesser extent, with lipid rafts. Conclusions: These data demonstrate that PLA-NP are internalized and, in general, tolerated by A549 cells, with no cytotoxicity and no secretion of pro-inflammatory mediators. However, PLA-NP exposure may induce modification of biological functions of A549 cells, which should be considered when designing drug delivery systems. Moreover, the pathways of PLA-NP internalization we detected could contribute to the improvement of selective uptake strategies.

Original languageEnglish
Article number11
JournalJournal of Nanobiotechnology
Publication statusPublished - 31 Jan 2017


  • Clathrin-coated pits
  • Drug delivery
  • Endocytosis
  • Lipid rafts
  • Nanoparticles

ASJC Scopus subject areas

  • Medicine (miscellaneous)
  • Bioengineering
  • Applied Microbiology and Biotechnology
  • Biomedical Engineering
  • Molecular Medicine
  • Pharmaceutical Science


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