ABSTRACT
Title
Cocaine and amphetamine modify intercellular communication interfering with the formation of tunneling nanotubes
Authors
C. Carone, F. Pederzoli, G. Leo, S. Genedani
Department of Biomedical Sciences, University of Modena and Reggio Emilia, Via Campi 287, 41125 Modena, Italy
Department of Biomedical Sciences, University of Modena and Reggio Emilia, Via Campi 287, 41125 Modena, Italy
Abstract
Tunneling nanotubes (TNTs) are the latest addition to the array of strategies used for intercellular signaling (Rustom A. et al. 2004). They are continuous conduits of the plasma membrane that allow direct physical connection of plasma membranes and cytosol among remote cells. TNTs are important for intercellular communication by mediating exchange of cellular components as well as signal transduction molecules and cellular organelles. Their physio-pathological role has not yet been fully clarified however, being involved in cell–cell communication, an essential function for homeostasis of multicellular aggregates can be ascribed to them. It is relevant to underline that modifications in homeostasis of defined brain areas may result in the neuroadaptive processes that underlie drug addiction.
On these bases, the influence of cocaine and amphetamine on TNTs formation has been investigated in live human U-87MG glioblastoma cells after 1 h exposition to the drug by confocal microscopy. Cocaine had opposite effects in the nanomolar range: at the concentration of 150 nM significantly increased the TNTs formation (+74.45 % in the ratio TNTs/cells) while at a higher concentration (300 nM) significantly decreased TNT number/cell (-28.25%). The stimulatory effect of cocaine 150 nM on TNTs formation has also been observed in SHSY5Y neuroblastoma cells. On the other hand, amphetamine reduced the TNT formation in U-87MG glioblastoma cells at 300 nM (-39.33) and had no effect at the lower concentration. Both drugs did not influence TNTs number at 150 µM. The dual action of cocaine might be explained by interaction of the drug with different cellular components. It is known that cocaine is a lipophilic compound thus at the lower concentration the main site of drug action might be the cell membrane in particular specific lipid platforms defined “Lipd Rafts” (LRs). A direct interaction of cocaine with “Lipid Rafts” has been recently suggested by our group (Genedani S. et al. 2010)and our recent mass spectrometry studies have shown that cocaine interacts with GM1, a main component of planar LRs. Moreover, a relationship between LRs and formation of TNTs in mast cells has been observed by Fifadara et al. (Fifadara N.H. et al. 2010). Increasing cocaine concentration a prevalence of an intracellular action (e.g. interaction of the drug with cytoskeleton components as observed in several brain regions of mice treated with cocaine (Kovacs K. et al. 2010)) might account for its inhibitory effect on TNTs formation. On the other hand, amphetamine appears unable to influence the physicochemical properties of cell membrane thus it has no effect at the concentration of 150 nM. At higher concentration (300 nM) amphetamine may exert an intracellular action with consequent inhibition of TNTs formation; literature data show the ability of amphetamine to reduce the synthesis of cytoskeleton components by interaction with MAP-2 protein (Putzke J. et al. 2007). We are now investigating the possible interaction between cocaine and amphetamine effect on TNTs formation. Moreover, the influence of dopaminergic agonists on TNTs will be studied in neuroblastoma cells.
The present results show a new mechanism used by psychostimulant drugs, in the nanomolar range, to influence intercellular communication. This might contribute to better understand the molecular mechanism/s of drug addiction and to identify new pharmacological targets for addiction treatment.
Rustom A, Saffrich R, Markovic I, Walther P, Gerdes H-H. Science 2004; 303:1007-10.
Genedani S, Carone C, Guidolin D, Filaferro M, Marcellino D, Fuxe K, Agnati LF. J Mol Neurosci. 2010 Jul;41(3):347-57.
Fifadara NH, Beer F, Ono S, Ono SJ.Int Immunol. 2010 Feb;22(2):113-28.
Kovacs K, Lajtha A, Sershen H. Brain Res Bull. 2010 Apr 29;82(1-2):109-17.
Putzke J, Spina MG, Büchler J, Kovar KA, Wolf G, Smalla KH. Addict Biol. 2007 Mar;12(1):69-80.
On these bases, the influence of cocaine and amphetamine on TNTs formation has been investigated in live human U-87MG glioblastoma cells after 1 h exposition to the drug by confocal microscopy. Cocaine had opposite effects in the nanomolar range: at the concentration of 150 nM significantly increased the TNTs formation (+74.45 % in the ratio TNTs/cells) while at a higher concentration (300 nM) significantly decreased TNT number/cell (-28.25%). The stimulatory effect of cocaine 150 nM on TNTs formation has also been observed in SHSY5Y neuroblastoma cells. On the other hand, amphetamine reduced the TNT formation in U-87MG glioblastoma cells at 300 nM (-39.33) and had no effect at the lower concentration. Both drugs did not influence TNTs number at 150 µM. The dual action of cocaine might be explained by interaction of the drug with different cellular components. It is known that cocaine is a lipophilic compound thus at the lower concentration the main site of drug action might be the cell membrane in particular specific lipid platforms defined “Lipd Rafts” (LRs). A direct interaction of cocaine with “Lipid Rafts” has been recently suggested by our group (Genedani S. et al. 2010)and our recent mass spectrometry studies have shown that cocaine interacts with GM1, a main component of planar LRs. Moreover, a relationship between LRs and formation of TNTs in mast cells has been observed by Fifadara et al. (Fifadara N.H. et al. 2010). Increasing cocaine concentration a prevalence of an intracellular action (e.g. interaction of the drug with cytoskeleton components as observed in several brain regions of mice treated with cocaine (Kovacs K. et al. 2010)) might account for its inhibitory effect on TNTs formation. On the other hand, amphetamine appears unable to influence the physicochemical properties of cell membrane thus it has no effect at the concentration of 150 nM. At higher concentration (300 nM) amphetamine may exert an intracellular action with consequent inhibition of TNTs formation; literature data show the ability of amphetamine to reduce the synthesis of cytoskeleton components by interaction with MAP-2 protein (Putzke J. et al. 2007). We are now investigating the possible interaction between cocaine and amphetamine effect on TNTs formation. Moreover, the influence of dopaminergic agonists on TNTs will be studied in neuroblastoma cells.
The present results show a new mechanism used by psychostimulant drugs, in the nanomolar range, to influence intercellular communication. This might contribute to better understand the molecular mechanism/s of drug addiction and to identify new pharmacological targets for addiction treatment.
Rustom A, Saffrich R, Markovic I, Walther P, Gerdes H-H. Science 2004; 303:1007-10.
Genedani S, Carone C, Guidolin D, Filaferro M, Marcellino D, Fuxe K, Agnati LF. J Mol Neurosci. 2010 Jul;41(3):347-57.
Fifadara NH, Beer F, Ono S, Ono SJ.Int Immunol. 2010 Feb;22(2):113-28.
Kovacs K, Lajtha A, Sershen H. Brain Res Bull. 2010 Apr 29;82(1-2):109-17.
Putzke J, Spina MG, Büchler J, Kovar KA, Wolf G, Smalla KH. Addict Biol. 2007 Mar;12(1):69-80.