p66Shc is involved in promoting HIF-1alpha accumulation and cell death in hypoxic T cells.
Hypoxia results in adaptationally appropriate alterations of gene expression through the activation of hypoxia-inducible factor (HIF)-1 to overcome any shortage of oxygen. Peripheral blood mononuclear cells may be exposed to low oxygen tensions for different times as they migrate between blood and various tissues. We and others have previously shown that T-cell adaptation to hypoxia is characterized by a modulation of cytokine expression and an inhibition of T-cell activation. We have recently demonstrated that the adaptor protein p66Shc negatively regulates T-cell activation and survival. We here show that hypoxia enhances HIF-1alpha accumulation and vascular endothelial growth factor production in T cells. Hypoxic T cells expressed high levels of p21(WAF1/CIP1), of the pro-apoptotic molecules BNIP3, a classic HIF target gene, and BAX, as well as low levels of the anti-apoptotic molecule BCLxl, associated with an induction of cell death. We found out that hypoxic T cells expressed p66Shc. Furthermore, using T-cell transfectants expressing p66Shc, as well as T cells derived from mice p66Shc-/-, we defined a role of p66Shc in T-cell responses to hypoxia. Of interest, hypoxic p66Shc-positive transfectants expressed higher level of HIF-1alpha than negative controls. Thus, p66Shc may play an important role in downstream hypoxic signaling, involving HIF-1alpha protein accumulation and cell death in T lymphocytes.
Carraro
Fabio
F
Department of Physiology, University of Siena, Siena, Italy.
Pucci
Annalisa
A
Pellegrini
Michela
M
Pelicci
Pier Giuseppe
PG
Baldari
Cosima T
CT
Naldini
Antonella
A
D048868:Adaptor Proteins, Signal Transducing / Q000096:biosynthesis / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D016923:Cell Death; D015687:Cell Hypoxia; D049109:Cell Proliferation; D002470:Cell Survival; D050759:Cyclin-Dependent Kinase Inhibitor p21 / Q000378:metabolism; D015536:Down-Regulation; D006801:Humans; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*; D019169:Jurkat Cells; D008213:Lymphocyte Activation; D008565:Membrane Proteins / Q000378:metabolism; D051379:Mice; D008822:Mice, Transgenic; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D055765:Shc Signaling Adaptor Proteins; D013154:Spleen / Q000166:cytology / Q000378:metabolism; D000071425:Src Homology 2 Domain-Containing, Transforming Protein 1; D013601:T-Lymphocytes / Q000378:metabolism*; D013997:Time Factors; D014162:Transfection; D015854:Up-Regulation; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism; D051028:bcl-2-Associated X Protein / Q000378:metabolism; D051020:bcl-X Protein / Q000378:metabolism
D048868:Adaptor Proteins, Signal Transducing; C090121:BNIP3 protein, human; C493956:CDKN1A protein, human; D050759:Cyclin-Dependent Kinase Inhibitor p21; C497442:HIF1A protein, human; C497443:Hif1a protein, mouse; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D008565:Membrane Proteins; D011518:Proto-Oncogene Proteins; D012333:RNA, Messenger; C528024:SHC1 protein, human; D055765:Shc Signaling Adaptor Proteins; C528034:Shc1 protein, mouse; D000071425:Src Homology 2 Domain-Containing, Transforming Protein 1; C467484:VEGFA protein, human; D042461:Vascular Endothelial Growth Factor A; D051028:bcl-2-Associated X Protein; D051020:bcl-X Protein