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IRE1‐alpha signaling can be related to palmitate‐induced insulin resistance in L6 myotubes
Author(s) -
Silva Patricia Ebersbach,
Poletto Ana Claudia,
Anhe Gabriel Forato,
Machado Ubiratan Fabres
Publication year - 2012
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.26.1_supplement.686.6
Subject(s) - glut4 , endoplasmic reticulum , unfolded protein response , insulin resistance , alpha (finance) , endocrinology , medicine , chemistry , myogenesis , insulin , biology , biochemistry , myocyte , construct validity , nursing , patient satisfaction
Recent studies showed that elevated free fatty acids (FFAs) can induce endoplasmic reticulum (ER) stress, and this, in turn, plays a role in the development of insulin resistance (IR). This work aimed to verify the effects of palmitate on GLUT4 and ER stress proteins in L6 cells. GLUT4, IRE1‐alpha and TRAF2 proteins were analyzed in myotubes treated with 0,75mM of palmitate during 1 to 12 hours. The results showed that palmitate caused a significant reduction of the GLUT4 protein content in all treatment periods (control: 99.99±4.3, 2 hours: 66.37±7.2*, 4 hours: 65.03±8.0*, 6 hours: 67.16±8.8*, 12 hours: 58.88±5.5*), the analysis also showed an increase of IRE1‐alpha protein within 4 hours of incubation (control: 100.00±0.0, 4 hours: 184.16±49.45*) and an important increase of TRAF2 protein at the first hour of treatment (control: 100.00±0.0, 1 hour: 125.20±9.07*). Results were expressed in arbitrary units, n=4 to 6, *P<0.05. These data showed that palmitate impaired GLUT4 expression what is preceded by activation of IRE1alpha/TRAF2 pathway. This data reinforces the proposition that FFA‐induced ER stress is associated with IR probably by reducing GLUT4 content through mechanisms not fully identified. Support: Fapesp 2010/09984‐5