Kalashnyk_2012_Life.Sci_91_1033

AIMS: Previously we demonstrated that mouse liver mitochondria express functional alpha7 nicotinic acetylcholine receptors (nAChRs). The aim of this study was to investigate whether the nAChRs are found in mitochondria of non-neuronal human cell lines. MAIN
METHODS: Three cell lines: U373 (astrocytes), U937 (monocytes) and Daudi (B lymphocytes) were examined by flow cytometry, Cell ELISA and fluorescent confocal microscopy using the antibodies against extracellular epitopes of alpha3, alpha4, alpha7, alpha9, beta2 and beta4 nAChR subunits. KEY FINDINGS: It is shown that the studied cells expressed different sets of nAChR subunits on the plasma membrane suggesting the presence of alpha7 nAChRs on all cells, of alpha3beta4 nAChRs on U373 cells and of alpha4beta2/alpha4beta4 nAChRs on U937 cells. In addition to nAChRs exposed on the surface, all cells contained a considerable intracellular pool of alpha3- and alpha7-containing nAChRs. The binding of alpha3-, alpha7- and beta4-specific antibodies partially overlapped with that of mitochondrial outer membrane translocase-specific antibody. Binding of alpha7-specific antibody also overlapped with that of MitoTracker Green, which binds to active mitochondria. SIGNIFICANCE: The data obtained suggest that a part of intracellular alpha3beta4 and alpha7 nAChRs in U373, U937 and Daudi cells is located on mitochondria. This finding complements our previous observation of alpha7 nAChRs in mouse liver mitochondria and reveals new intracellular targets for cholinergic regulation.