title: Functional gains in energy and cell metabolism after TSPO gene insertion.
abstract: Recent loss-of-function studies in tissue-specific as well as global Tspo (Translocator Protein 18 kDa) knockout mice have not confirmed its long assumed indispensability for the translocation of cholesterol across the mitochondrial inter-membrane space, a rate-limiting step in steroid biosynthesis. Instead, recent studies in global Tspo knockout mice indicate that TSPO may play a more fundamental role in cellular bioenergetics, which may include the indirect down-stream regulation of transport or metabolic functions. To examine whether overexpression of the TSPO protein alters the cellular bioenergetic profile, Jurkat cells with low to absent endogenous expression were transfected with a TSPO construct to create a stable cell line with de novo expression of exogenous TSPO protein. Expression of TSPO was confirmed by RT-qPCR, radioligand binding with [3H]PK11195 and immunocytochemistry with a TSPO antibody. We demonstrate that TSPO gene insertion causes increased transcription of genes involved in the mitochondrial electron transport chain. Furthermore, TSPO insertion increased mitochondrial ATP production as well as cell excitability, reflected in a decrease in patch clamp recorded rectified K channel currents. These functional changes were accompanied by an increase in cell proliferation and motility, which were inhibited by PK11195, a selective ligand for TSPO. We suggest that TSPO may serve a range of functions that can be viewed as downstream regulatory effects of its primary, evolutionary conserved role in cell metabolism and energy production.
authors.affiliation: a Australian Nuclear Science and Technology Organisation , Lucas Heights , NSW , Australia.|b Faculty of Health Science and Brain and Mind Centre, University of Sydney , NSW , Australia.
authors.forename: Guo-Jun
authors.initials: GJ
authors.lastname: Liu
authors.affiliation: a Australian Nuclear Science and Technology Organisation , Lucas Heights , NSW , Australia.
authors.forename: Ryan J
authors.initials: RJ
authors.lastname: Middleton
authors.affiliation: a Australian Nuclear Science and Technology Organisation , Lucas Heights , NSW , Australia.|c Department of Health Technology and Informatics , Hong Kong Polytechnic University , Hung Hom, Hong Kong , China.
authors.forename: Winnie Wai-Ying
authors.initials: WW
authors.lastname: Kam
authors.affiliation: d NCRIS Biologics Facility, Australian Institute for Bioengineering and Nanotechnology, University of Queensland , QLD , Australia.
authors.forename: David Y
authors.initials: DY
authors.lastname: Chin
authors.affiliation: a Australian Nuclear Science and Technology Organisation , Lucas Heights , NSW , Australia.|b Faculty of Health Science and Brain and Mind Centre, University of Sydney , NSW , Australia.
authors.forename: Claire R
authors.initials: CR
authors.lastname: Hatty
authors.affiliation: a Australian Nuclear Science and Technology Organisation , Lucas Heights , NSW , Australia.|b Faculty of Health Science and Brain and Mind Centre, University of Sydney , NSW , Australia.
authors.forename: Ronald H Y
authors.initials: RH
authors.lastname: Chan
authors.affiliation: a Australian Nuclear Science and Technology Organisation , Lucas Heights , NSW , Australia.|b Faculty of Health Science and Brain and Mind Centre, University of Sydney , NSW , Australia.
authors.forename: Richard B
authors.initials: RB
authors.lastname: Banati
mesh_terms: D000255:Adenosine Triphosphate / Q000096:biosynthesis; D000818:Animals; D002465:Cell Movement; D049109:Cell Proliferation; D004579:Electron Transport / Q000235:genetics; D004734:Energy Metabolism; D006801:Humans; D019169:Jurkat Cells; D008928:Mitochondria / Q000378:metabolism; D016254:Mutagenesis, Insertional / Q000235:genetics*; D015221:Potassium Channels / Q000378:metabolism; D018079:Receptors, GABA / Q000235:genetics* / Q000378:metabolism; D015203:Reproducibility of Results; D014162:Transfection; D015854:Up-Regulation / Q000235:genetics
chemical_list: D015221:Potassium Channels; D018079:Receptors, GABA; C499229:TSPO protein, human; D000255:Adenosine Triphosphate
keywords: TSPO; cell metabolism; energy production; mitochondria; patch clamp