عنوان المقالة:Sandra Incerpi, Meng-Ti Hsieh, Hung-Yun Lin, Guei-Yun Cheng, Paolo De Vito, Anna Maria Fiore, R. G. Ahmed, Rosanna Salvia, Elena Candelotti, Stefano Leone, Paolo Luly, Jens Z. Pedersen, Faith B. Davis, Paul J. Davis, 2014. Thyroid hormone inhibition in L6 myoblasts of IGF-I-mediated glucose uptake and proliferation: new roles for integrin αvβ3. Am. J. Physiol. Cell Physiol. 307, C150–C161.
Sandra Incerpi, Meng-Ti Hsieh, Hung-Yun Lin, Guei-Yun Cheng, Paolo De Vito, Anna Maria Fiore, R. G. Ahmed, Rosanna Salvia, Elena Candelotti, Stefano Leone, Paolo Luly, Jens Z. Pedersen, Faith B. Davis, Paul J. Davis,
الملخص العربي
Thyroid hormone inhibition in L6 myoblasts of IGF-Imediated
glucose uptake and proliferation: new roles for integrin v3. Am
J Physiol Cell Physiol 307: C150–C161, 2014. First published May 7, 2014;
doi:10.1152/ajpcell.00308.2013.—Thyroid hormones L-thyroxine (T4)
and 3,3=,5-triiodo-L-thyronine (T3) have been shown to initiate shortand
long-term effects via a plasma membrane receptor site located on
integrin v3. Also insulin-like growth factor type I (IGF-I) activity
is known to be subject to regulation by this integrin. To investigate the
possible cross-talk between T4 and IGF-I in rat L6 myoblasts, we have
examined integrin v3-mediated modulatory actions of T4 on glucose
uptake, measured through carrier-mediated 2-deoxy-[3H]-D-glucose
uptake, and on cell proliferation stimulated by IGF-I, assessed by
cell counting, [3H]-thymidine incorporation, and fluorescence-activated
cell sorting analysis. IGF-I stimulated glucose transport and cell
proliferation via the cell surface IGF-I receptor (IGFIR) and, downstream
of the receptor, by the phosphatidylinositol 3-kinase signal
transduction pathway. Addition of 0.1 nM free T4 caused little or no
cell proliferation but prevented both glucose uptake and proliferative
actions of IGF-I. These actions of T4 were mediated by an Arg-Gly-
Asp (RGD)-sensitive pathway, suggesting the existence of crosstalk
between IGFIR and the T4 receptor located near the RGD recognition
site on the integrin. An RGD-sequence-containing integrin inhibitor, a
monoclonal antibody to v3, and the T4 metabolite tetraiodothyroacetic
acid all blocked the inhibition by T4 of IGF-I-stimulated
glucose uptake and cell proliferation. Western blotting confirmed
roles for activated phosphatidylinositol 3-kinase and extracellular
regulated kinase 1/2 (ERK1/2) in the effects of IGF-I and also showed
a role for ERK1/2 in the actions of T4 that modified the effects of
IGF-I. We conclude that thyroid hormone inhibits IGF-I-stimulated
glucose uptake and cell proliferation in L6 myoblasts.
Ahmed R. G. | Ahmed R. G. | 2259