Acute mTOR inhibition induces insulin resistance and alters substrate utilization in vivo

Kleinert, Maximilian; Sylow, Lykke; Fazakerley, Daniel J.; Krycer, James R.; Thomas, Kristen C.; Oxbøll, Anne-Julie; Jordy, Andreas Børsting; Jensen, Thomas E.; Yang, Guang; Schjerling, Peter; Kiens, Bente; James, David E.; Rüegg, Markus A.

doi:10.1016/j.molmet.2014.06.004

Cited by 71 publications

(73 citation statements)

References 48 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…As expected, insulin trigged phosphorylation of both endogenous Akt (lower band) and mCherry-CRY2-Akt2 (upper band) at residues Thr308 and Ser473. Both sites showed a higher degree of phosphorylation with 100 nM insulin compared to 10 nM insulin, consistent with several papers showing that insulin stimulation of Akt phosphorylation and GLUT4 translocation is dose dependent (Cheney et al, 2011;Govers et al, 2004;Kleinert et al, 2014;Martinez et al, 2010). Importantly, stimulation of Opto-Akt2 with light produced strong phosphorylation of mCherry-CRY-Akt2 at Thr308 and Ser473 (and not the endogenous Akt), whereas Opto-PIP 3 yielded a similar degree of responsiveness of endogenous Akt.…”

Section: Opto-pip 3 Promotes Glut4 Vesicle Exocytosis In 3t3-l1 Adiposupporting

confidence: 90%

Optogenetic activation reveals distinct roles of PIP3 and Akt in adipocyte insulin action

Nan

Fan

et al. 2016

Journal of Cell Science

View full text Add to dashboard Cite

Glucose transporter 4 (GLUT4; also known as SLC2A4) resides on intracellular vesicles in muscle and adipose cells, and translocates to the plasma membrane in response to insulin. The phosphoinositide 3-kinase (PI3K)-Akt signaling pathway plays a major role in GLUT4 translocation; however, a challenge has been to unravel the potentially distinct contributions of PI3K and Akt (of which there are three isoforms, Akt1-Akt3) to overall insulin action. Here, we describe new optogenetic tools based on CRY2 and the N-terminus of CIB1 (CIBN). We used these 'Opto' modules to activate PI3K and Akt selectively in time and space in 3T3-L1 adipocytes. We validated these tools using biochemical assays and performed live-cell kinetic analyses of IRAP-pHluorin translocation (IRAP is also known as LNPEP and acts as a surrogate marker for GLUT4 here). Strikingly, Opto-PIP 3 largely mimicked the maximal effects of insulin stimulation, whereas Opto-Akt only partially triggered translocation. Conversely, drug-mediated inhibition of Akt only partially dampened the translocation response of Opto-PIP 3 . In spatial optogenetic studies, focal targeting of Akt to a region of the cell marked the sites where IRAP-pHluorin vesicles fused, supporting the idea that local Aktmediated signaling regulates exocytosis. Taken together, these results indicate that PI3K and Akt play distinct roles, and that PI3K stimulates Akt-independent pathways that are important for GLUT4 translocation.

show abstract

Section: Opto-pip 3 Promotes Glut4 Vesicle Exocytosis In 3t3-l1 Adiposupporting

confidence: 90%

Optogenetic activation reveals distinct roles of PIP3 and Akt in adipocyte insulin action

Nan

Fan

et al. 2016

Journal of Cell Science

View full text Add to dashboard Cite

show abstract

“…The protein kinase mTOR interacts with signaling components to form two complexes: mTOR complex 1 (mTORC1), which regulates translation initiation, and mTORC2, a regulator of protein kinase B (PKB) (48,53,92). Upstream regulators of mTOR are not well characterized but include Deptor, an inhibitor of mTORC1 and mTORC2 (65), and proline-rich Akt substrate of 40 kDa (PRAS40), which inhibits mTORC1 by binding to Raptor, a core mTORC1 member (82).…”

mentioning

confidence: 99%

Pulsatile delivery of a leucine supplement during long-term continuous enteral feeding enhances lean growth in term neonatal pigs

Boutry

El‐Kadi

Suryawan

et al. 2016

American Journal of Physiology-Endocrinology and Metabolism

View full text Add to dashboard Cite

TA. Pulsatile delivery of a leucine supplement during long-term continuous enteral feeding enhances lean growth in term neonatal pigs. Am J Physiol Endocrinol Metab 310: E699 -E713, 2016. First published February 16, 2016 doi:10.1152/ajpendo.00479.2015.-Neonatal pigs are used as a model to study and optimize the clinical treatment of infants who are unable to maintain oral feeding. Using this model, we have shown previously that pulsatile administration of leucine during continuous feeding over 24 h via orogastric tube enhanced protein synthesis in skeletal muscle compared with continuous feeding alone. To determine the long-term effects of leucine pulses, neonatal piglets (n ϭ 11-12/group) were continuously fed formula via orogastric tube for 21 days, with an additional parenteral infusion of either leucine (CON ϩ LEU; 800 mol·kg Ϫ1 ·h Ϫ1 ) or alanine (CON ϩ ALA) for 1 h every 4 h. The results show that body and muscle weights and lean gain were ϳ25% greater, and fat gain was 48% lower in CON ϩ LEU than CON ϩ ALA; weights of other tissues were unaffected by treatment. Fractional protein synthesis rates in longissimus dorsi, gastrocnemius, and soleus muscles were ϳ30% higher in CON ϩ LEU compared with CON ϩ ALA and were associated with decreased Deptor abundance and increased mTORC1, mTORC2, 4E-BP1, and S6K1 phosphorylation, SNAT2 abundance, and association of eIF4E with eIF4G and RagC with mTOR. There were no treatment effects on PKB, eIF2␣, eEF2, or PRAS40 phosphorylation, Rheb, SLC38A9, v-ATPase, LAMTOR1, LAMTOR2, RagA, RagC, and LAT1 abundance, the proportion of polysomes to nonpolysomes, or the proportion of mRNAs encoding rpS4 or rpS8 associated with polysomes. Our results demonstrate that pulsatile delivery of a leucine supplement during 21 days of continuous enteral feeding enhances lean growth by stimulating the mTORC1-dependent translation initiation pathway, leading to protein synthesis in skeletal muscle of neonates. leucine; growth; protein metabolism; orogastric feeding; infant GROWTH AND DEVELOPMENT DURING CHILDHOOD is the traditional measure of overall nutritional status. Poor growth in early infancy is associated with increased risk for adverse long-term health outcomes, including programming of obesity (63

show abstract

“…Since these inhibitors do not interact with FKBP12, potential side effects originating from its sequestration should be circumvented. The mTOR kinase inhibitors are not specific for mTORC1, and because mTORC2 inhibition leads to insulin resistance, it is likely that these inhibitors would lead to the same side effects [101]. In the context of aging, the dosing schedule would have to be finely adjusted accordingly.…”

Section: Introductionmentioning

confidence: 99%

Age-Related Neurodegeneration Prevention Through mTOR Inhibition: Potential Mechanisms and Remaining Questions

Jahrling¹,

Laberge

2015

CTMC

View full text Add to dashboard Cite

With the global aging population, Alzheimer's disease, Parkinson's disease and mild cognition impairment are increasing in prevalence. The success of rapamycin as an agent to extend lifespan in various organisms, including mice, brings hope that chronic mTOR inhibition could also refrain age-related neurodegeneration. Here we review the evidence suggesting that mTOR inhibition - mainly with rapamycin - is a valid intervention to delay age-related neurodegeneration. We discuss the potential mechanisms by which rapamycin may facilitate neurodegeneration prevention or restoration of cognitive function. We also discuss the known side effects of rapamycin and provide evidence to alleviate exaggerated concerns regarding its wider clinical use. We explore the small molecule alternatives to rapamycin and propose future directions for their development, mainly by exploring the possibility of targeting the downstream effectors of mTOR: S6K1 and especially S6K2. Finally, we discuss the strengths and weaknesses of the models used to determine intervention efficacy for neurodegeneration. We address the difficulties of interpreting data using the common way of investigating the efficacy of interventions to delay/prevent neurodegeneration by observing animal behavior while these animals are under treatment. We propose an experimental design that should isolate the variable of aging in the experimental design and resolve the ambiguity present in recent literature.

show abstract

Acute mTOR inhibition induces insulin resistance and alters substrate utilization in vivo

Cited by 71 publications

References 48 publications

Optogenetic activation reveals distinct roles of PIP3 and Akt in adipocyte insulin action

Optogenetic activation reveals distinct roles of PIP3 and Akt in adipocyte insulin action

Pulsatile delivery of a leucine supplement during long-term continuous enteral feeding enhances lean growth in term neonatal pigs

Age-Related Neurodegeneration Prevention Through mTOR Inhibition: Potential Mechanisms and Remaining Questions

Contact Info

Product

Resources

About