Pro-inflammatory effects of different MWCNTs dispersions in p16^INK4A-deficient telomerase-expressing human keratinocytes but not in human SV-40 immortalized sebocytes

Abstract

We tested whether multi-walled carbon nanotubes (MWCNTs) induce oxidative stress and a pro-inflammatory response in human N-hTERT telomerase-immortalized keratinocytes, in human SZ95 SV-40 immortalized sebocytes and in in vitro reconstructed epidermises. MWCNTS were tested in various dispersion states, from raw and agglomerated particles to isolated entities obtained by sonication in the presence of dispersive agents (hydroxypropylcellulose and Pluronic F108). It was observed that: (a) Contrary to individualized MWCNTs, agglomerated particles prepared by suspension into pure water increased the intracellular levels of reactive oxygen species as well as the expression and secretion of interleukin-8 in N-hTERT cells; (b) the inflammatory signature of MWCNTs in N-hTERT cells, drawn by transcriptomic analysis with low-density microfluidic cards, included various other cytokines such as interleukin-6 or C-C motif ligand 3; (c) the pro-inflammatory effects of MWCNTs, as assessed by interleukin-8 transcript level and protein release, were not observed in SZ95 cells; and (d) the secretion of interleukins-1α and -8 from in vitro reconstructed epidermal tissues, used as specific markers for skin irritation and sensitization, was unaffected in presence of MWCNTs, confirming that the cornified layer is an efficient barrier against MWCNTs.

Keywords::

• Carbon nanotube
• epidermis
• keratinocyte
• oxidative stress
• inflammation

Acknowledgements

O. Toussaint is a Senior Research Associate of the Belgian FNRS. SZ95 and N-hTERT keratinocytes were kind gifts respectively from Prof. C.C. Zouboulis (Departments of Dermatology, Venereology, Allergology and Immunology, Dessau Medical Center) and from J.G. Rheinwald (Department of Medicine and Harvard Skin Disease Research Center).

Declaration of interest: This work was supported by the Direction Générale des Technologies de la Recherche et de l'Energie (DGTRE) of the Walloon Region of Belgium (Nanotoxico Pole of Excellence, RW/FUNDP research convention No. 516252, and Silicalloy project, RW/FUNDP research convention No. 6144). The authors report no conflict of interest. The authors alone are responsible for the content and writing of the paper.