Rapamycin negatively impacts insulin signaling, glucose uptake and uncoupling protein-1 in brown adipocytes.
New onset diabetes after transplantation (NODAT) is a metabolic disorder that affects 40% of patients on immunosuppressive agent (IA) treatment, such as rapamycin (also known as sirolimus). IAs negatively modulate insulin action in peripheral tissues including skeletal muscle, liver and white fat. However, the effects of IAs on insulin sensitivity and thermogenesis in brown adipose tissue (BAT) have not been investigated. We have analyzed the impact of rapamycin on insulin signaling, thermogenic gene-expression and mitochondrial respiration in BAT. Treatment of brown adipocytes with rapamycin for 16h significantly decreased insulin receptor substrate 1 (IRS1) protein expression and insulin-mediated protein kinase B (Akt) phosphorylation. Consequently, both insulin-induced glucose transporter 4 (GLUT4) translocation to the plasma membrane and glucose uptake were decreased. Early activation of the N-terminal Janus activated kinase (JNK) was also observed, thereby increasing IRS1 Ser 307 phosphorylation. These effects of rapamycin on insulin signaling in brown adipocytes were partly prevented by a JNK inhibitor. In vivo treatment of rats with rapamycin for three weeks abolished insulin-mediated Akt phosphorylation in BAT. Rapamycin also inhibited norepinephrine (NE)-induced lipolysis, the expression of peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α) and uncoupling protein (UCP)-1 in brown adipocytes. Importantly, basal mitochondrial respiration, proton leak and maximal respiratory capacity were significantly decreased in brown adipocytes treated with rapamycin. In conclusion, we demonstrate, for the first time the important role of brown adipocytes as target cells of rapamycin, suggesting that insulin resistance in BAT might play a major role in NODAT development.
Institute of Biomedicine Alberto Sols (CSIC/UAM), E-28029 Madrid, Spain.
Ester
E
García-Casarrubios
Institute of Biomedicine Alberto Sols (CSIC/UAM), E-28029 Madrid, Spain; Center for Neuroscience and Cell Biology, University of Coimbra, E-3000 Coimbra, Portugal.
Carlos
C
de Moura
Institute of Biomedicine Alberto Sols (CSIC/UAM), E-28029 Madrid, Spain; Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Instituto de Salud Carlos III, Spain.
Ana I
AI
Arroba
Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Instituto de Salud Carlos III, Spain.
Nuria
N
Pescador
Department of Biochemistry and Physiology, Institut de Biomedicina de la Universitat de Barcelona (IBUB), Universitat de Barcelona, E-08028 Barcelona, Spain; Centro de Investigación Biomédica en Red de Fisiopatología de la Obesidad y la Nutrición (CIBEROBN), Instituto de Salud Carlos III, E-28029 Madrid, Spain.
María
M
Calderon-Dominguez
Institute of Biomedicine Alberto Sols (CSIC/UAM), E-28029 Madrid, Spain.
Laura
L
Garcia
Department of Biochemistry and Physiology, Institut de Biomedicina de la Universitat de Barcelona (IBUB), Universitat de Barcelona, E-08028 Barcelona, Spain; Centro de Investigación Biomédica en Red de Fisiopatología de la Obesidad y la Nutrición (CIBEROBN), Instituto de Salud Carlos III, E-28029 Madrid, Spain.
Laura
L
Herrero
Department of Biochemistry and Physiology, Institut de Biomedicina de la Universitat de Barcelona (IBUB), Universitat de Barcelona, E-08028 Barcelona, Spain; Centro de Investigación Biomédica en Red de Fisiopatología de la Obesidad y la Nutrición (CIBEROBN), Instituto de Salud Carlos III, E-28029 Madrid, Spain.
Dolors
D
Serra
Centro de Biología Molecular "Severo Ochoa" (CSIC-UAM) and Departamento de Biología Molecular, Universidad Autónoma de Madrid, 28049 Madrid, Spain; Instituto de Investigación Sanitaria Princesa (IIS-IP), 28006 Madrid, Spain.
Susana
S
Cadenas
Center for Neuroscience and Cell Biology, University of Coimbra, E-3000 Coimbra, Portugal; Laboratory of Pharmacology and Experimental Therapeutics, Institute for Biomedical Imaging and Life Sciences (IBILI), Faculty of Medicine, University of Coimbra, E-3000-548 Coimbra, Portugal.
Flavio
F
Reis
Center for Neuroscience and Cell Biology, University of Coimbra, E-3000 Coimbra, Portugal; Department of Geriatrics, University of Arkansas for Medical Sciences, Little Rock, AR 72202, United States; Arkansas Children's Research Institute, Little Rock, AR 72202, United States. Electronic address: ecarvalh@cnc.uc.pt.
Eugenia
E
Carvalho
Institute of Biomedicine Alberto Sols (CSIC/UAM), E-28029 Madrid, Spain.
Maria Jesus
MJ
Obregon
Institute of Biomedicine Alberto Sols (CSIC/UAM), E-28029 Madrid, Spain; Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Instituto de Salud Carlos III, Spain. Electronic address: avalverde@iib.uam.es.
Ángela M
ÁM
Valverde
D052437:Adipocytes, Brown / Q000187:drug effects* / Q000378:metabolism; D002001:Adipose Tissue, Brown / Q000187:drug effects / Q000378:metabolism; D000818:Animals; D019069:Cell Respiration / Q000187:drug effects; D015870:Gene Expression / Q000187:drug effects; D005947:Glucose / Q000378:metabolism*; D051275:Glucose Transporter Type 4 / Q000378:metabolism; D007328:Insulin / Q000378:metabolism*; D055504:Insulin Receptor Substrate Proteins / Q000378:metabolism; D007333:Insulin Resistance / Q000502:physiology; D008297:Male; D008928:Mitochondria / Q000187:drug effects / Q000378:metabolism; D000071248:Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha / Q000378:metabolism; D010766:Phosphorylation / Q000187:drug effects; D051381:Rats; D017207:Rats, Sprague-Dawley; D017208:Rats, Wistar; D015398:Signal Transduction / Q000187:drug effects*; D020123:Sirolimus / Q000494:pharmacology*; D022722:Thermogenesis / Q000187:drug effects; D000071256:Uncoupling Protein 1 / Q000378:metabolism*
D051275:Glucose Transporter Type 4; D007328:Insulin; D055504:Insulin Receptor Substrate Proteins; D000071248:Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha; C501429:Ppargc1a protein, rat; C000604373:Ucp1 protein, rat; D000071256:Uncoupling Protein 1; D005947:Glucose; D020123:Sirolimus
Bioenergetics; Brown adipocytes; Insulin signaling; NODAT; Thermogenesis