Multi-walled carbon nanotubes change morpho-functional and GABA characteristics of mouse cortical astrocytes

Abstract

BackgroundMulti-walled carbon nanotubes (MW-CNTs) have been extensively explored for their possible beneficial use in the nervous system. CNTs have shown to modulate neuronal growth and electrical properties, but its effect that varying length of MW-CNTs on primary astrocyte roles have not been clearly demonstrated yet.ResultsWe investigate here the effect of MW-CNTs on astrocytic morphology, cell–cell interaction and the distribution of intracellular GABA (gamma-amino butyric acid). Primary cultured cortical astrocytes on MW-CNT-coated glass coverslips grow rounder and make more cell–cell interactions, with many cell processes, compared to astrocytes on poly-d-lysine (PDL) coverslips. In addition, intracellular GABA spreads into the cell processes of astrocytes on MW-CNT coverslips. When this GABA spreads into cell processes from the cell body GABA can be released more easily and in larger quantities compared to astrocytes on PDL coverslips.ConclusionsOur result confirm that MW-CNTs modulate astrocytic morphology, the distribution of astrocytic GABA, cell–cell interactions and the extension of cell processes. CNTs look to be a promising material for use neuroprosthetics such as brain-machine interface technologies.Electronic supplementary materialThe online version of this article (doi:10.1186/s12951-015-0152-y) contains supplementary material, which is available to authorized users.

Distribution in the brain and possible neuroprotective effects of intranasally delivered multi-walled carbon nanotubes

“…a-MWCNTs 2 were also found to internalize in GABAergic glial cells (GAD + /GFAP + cells) in both healthy and diabetic rats ( Figure 6B). This result, indicating that almost exclusively GABAergic astrocytes and neurons are able to uptake MWCNTs in vivo after their intranasal delivery, corroborate the previously reported in vitro evidences of MWCNTs internalization in mouse cortical GABAergic astrocytes 43 . Moreover, although percentage of total GAD + cells did not vary neither after diabetes induction nor after treatment with both MWCNTs ( Figure 6C), the percentage of GAD + cells that internalized a-MWCNTs 2 was significantly decreased in treated diabetic rats as compared to treated healthy rats ( Figure 4D).…”

Glia and gliotransmitters on carbon nanotubes

“…Astrocytes can form gap junctions with neighboring cells, thereby forming interconnected groups of cells sharing a common cytoplasm [26]. We suggest that astrocytes on MW-CNTs (50 nm, 1,000 nm) have more cell–cell interaction ( p  < 0.05), with higher numbers of cell processes compared with those seen on PDL coverslips [16]. Some reports show that the cause of neurodegenerative diseases, such as Parkinson’s disease and AD, is a progressive loss of structure or function of neurons, as well as neuronal cell death.…”

“…Based on these studies, we discuss functionalized CNTs which can implant in the brain for brain disease therapy and modulate GABA. We investigated intracellular GABA distribution on MW-CNT and PDL coverslips (Figure 1) [16]. PDL is a positively charged material which is generally used to attach cells on to culture dishes and used as a control group.…”

“…In addition, CNTs have been shown to stimulate neurons efficiently and have long-term stability, while eliciting a significantly reduced inflammatory response in Parkinsonian rodents [14]. Recently, CNTs have been shown to modulate morpho-functional characteristics of glia as well as neurons [15,16]. Among the various types of glia, astrocytes occupy the greatest proportion (about 50%) in the brain and can make bidirectional communication with neurons.…”

Evaluation of multiwalled carbon nanotube cytotoxicity in cultures of human brain microvascular endothelial cells grown on plastic or basement membrane

“…Even gold nanoparticles, widely considered to exhibit little toxicity and high biocompatibility, can induce neurotoxic effects (Jung et al, 2014), which emphasizes the need for rigorous studies evaluating the potential neurotoxicity of nanomaterials. The cytotoxicity due to CNT exposure has been evaluated in various brain cell types including microglia,(Bardi et al, 2013; Bussy et al, 2015) astrocytes(Meng et al, 2013; Min et al, 2015; Zhang et al, 2011) and neurons(Bussy et al, 2015; Lee et al, 2011). The outcomes of these studies vary widely with some research indicating that CNTs are generally safe while others find CNTs to be cytotoxic and induce inflammation.…”