Loss of Proliferation and Antigen Presentation Activity following Internalization of Polydispersed Carbon Nanotubes by Primary Lung Epithelial Cells

Mandavi Kumari,Sumedha Sachar,Rajiv K Saxena,Nikos K Karamanos

doi:10.1371/journal.pone.0031890

Mandavi Kumari, Sumedha Sachar + Show 2 more

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https://doi.org/10.1371/journal.pone.0031890

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Journal: PloS one	Publication Date: Feb 27, 2012
Citations: 34	License type: CC BY 4.0

Affiliation: Jawaharlal Nehru University, South Asian University

Abstract

Interactions between poly-dispersed acid functionalized single walled carbon nanotubes (AF-SWCNTs) and primary lung epithelial (PLE) cells were studied. Peritoneal macrophages (PMs, known phagocytic cells) were used as positive controls in this study. Recovery of live cells from cultures of PLE cells and PMs was significantly reduced in the presence of AF-SWCNTs, in a time and dose dependent manner. Both PLE cells as well as PMs could take up fluorescence tagged AF-SWCNTs in a time dependent manner and this uptake was significantly blocked by cytochalasin D, an agent that blocks the activity of acto-myosin fibers and therefore the phagocytic activity of cells. Confocal microscopic studies confirmed that AF-SWCNTs were internalized by both PLE cells and PMs. Intra-trachially instilled AF-SWCNTs could also be taken up by lung epithelial cells as well as alveolar macrophages. Freshly isolated PLE cells had significant cell division activity and cell cycling studies indicated that treatment with AF-SWCNTs resulted in a marked reduction in S-phase of the cell cycle. In a previously standardized system to study BCG antigen presentation by PLE cells and PMs to sensitized T helper cells, AF-SWCNTs could significantly lower the antigen presentation ability of both cell types. These results show that mouse primary lung epithelial cells can efficiently internalize AF-SWCNTs and the uptake of nanotubes interfered with biological functions of PLE cells including their ability to present BCG antigens to sensitized T helper cells.

Highlights

Due to their unique structure and remarkable electrical and mechanical properties, carbon nanotubes (CNTs) have been used in wide applications in electronics, sensing, gas storage, aerospace, field-emission devices, catalytic supports, biomedical engineering and medical chemistry [1], [2], [3]
Recovery of cells exposed to AF-Single-walled carbon nanotubes (SWCNTs) (50 mg/ml) fell approximately by 15% as compared to the cell recovery in control cultures at 24 h, and further by 40% at 72 hour time point. For both peritoneal macrophages (PMs) and primary lung epithelial (PLE) cells, toxic effect of 50 mg/ml dose was marginally more than the effect of lower 10 mg/ml dose (p,0.05) These results indicate that AF-SWCNTs preparations are toxic to both PLE cells as well as PMs in a time and dose dependent manner, though the effect appears to be more pronounced for PMs
The aim of the present study was to investigate the interaction between AF-SWCNTs and primary lung epithelial (PLE) cells as well as macrophages

Summary

Introduction

Due to their unique structure and remarkable electrical and mechanical properties, carbon nanotubes (CNTs) have been used in wide applications in electronics, sensing, gas storage, aerospace, field-emission devices, catalytic supports, biomedical engineering and medical chemistry [1], [2], [3]. The increasing potential applications of SWCNTs raise the issue of potential toxic effects of these materials, as they are inhaled and become airborne due to low density and small size [6]. A mild and transient pulmonary inflammatory response in rats instilled intra-tracheally with SWCNTs, with subsequent development of multifocal granulomas in the lungs was reported [8]. Immunosuppressive effect of SWCNTs resulting functional respiratory deficiencies and decreased bacterial clearance was reported [10]. The acid functionalized SWCNTs (AF-SWCNTs) that are de-bundled and disperse in aqueous solution, were found to be highly toxic to the mouse lung epithelial cell line LA4 and induced strong pulmonary inflammation in mice [11]. AF-SWCNTs instilled intratracheally have been shown to produce acute toxic effects in heart, suggesting that the nanotubes could traverse lung and reach heart [12]

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