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Diabetologia

, Volume 57, Issue 11, pp 2393–2404 | Cite as

Macrophage mTORC1 disruption reduces inflammation and insulin resistance in obese mice

  • Hongfeng Jiang
  • Marit Westerterp
  • Chunjiong Wang
  • Yi Zhu
  • Ding AiEmail author
Article

Abstract

Aims/hypothesis

Inflammatory factors secreted by macrophages play an important role in obesity-related insulin resistance. Being at the crossroads of a nutrient–hormonal signalling network, the mammalian target of rapamycin complex 1 (mTORC1) controls important functions in the regulation of energy balance and peripheral metabolism. However, the role of macrophage mTORC1 in insulin resistance is still unclear. In the current study, we investigated the physiological role of macrophage mTORC1 in regulating inflammation and insulin sensitivity.

Methods

We generated mice deficient in the regulatory associated protein of mTOR (Raptor) in macrophages, by crossing Raptor (also known as Rptor) floxed mice (Raptor flox/flox) with mice expressing Cre recombinase under the control of the Lysm-Cre promoter (Mac-Raptor KO). We fed mice chow or high-fat diet (HFD) and assessed insulin sensitivity in liver, muscle and adipose tissue. Subsequently, we measured inflammatory gene expression in liver and adipose tissue and investigated the role of Raptor deficiency in the regulation of inflammatory responses in peritoneal macrophages from HFD-fed mice or in palmitic acid-stimulated bone marrow-derived macrophages (BMDMs).

Results

Mac-Raptor KO mice fed HFD had improved systemic insulin sensitivity compared with Raptor flox/flox mice. Macrophage Raptor deficiency reduced inflammatory gene expression in liver and adipose tissue, fatty liver and adipose tissue macrophage content in response to HFD. In peritoneal macrophages from mice fed with an HFD for 12 weeks, macrophage Raptor deficiency decreased inflammatory gene expression, through attenuation of the inactivation of Akt and subsequent inhibition of the inositol-requiring element 1α/clun NH2-terminal kinase–nuclear factor kappa-light-chain-enhancer of activated B cells (IRE1α/JNK/NFκB) pathways. Similarly, mTOR inhibition as a result of Raptor deficiency or rapamycin treatment decreased palmitic acid-induced inflammatory gene expression in BMDMs in vitro.

Conclusions/interpretation

The disruption of mTORC1 signalling in macrophages protects mice against inflammation and insulin resistance potentially by inhibiting HFD- and palmitic acid-induced IRE1α/JNK/NFκB pathway activation.

Keywords

Inflammation Insulin resistance mTORC1 

Abbreviations

ATF6

Activating transcription factor 6

ATM

Adipose tissue macrophage

BMDM

Bone marrow-derived macrophage

CD

Chow diet

ConA

Concanavalin A

DIO

Diet-induced obesity

eIF2α

Eukaryotic translation initiation factor 2α

ER

Endoplasmic reticulum

HFD

High-fat diet

IPGTT

Intraperitoneal glucose tolerance test

IPITT

Intraperitoneal insulin tolerance test

IRE1α

Inositol-requiring element 1α

JNK

cJun NH2-terminal kinase

mTORC1/2

Mammalian target of rapamycin complex 1/2

NF-κB

Nuclear factor κB

NMR

Nuclear magnetic resonance

PERK

RNA-dependent protein kinase-like ER kinase

p70S6k

p70 S6 kinase

Raptor

Regulatory associated protein of mTOR

SFA

Saturated fatty acid

TG

Triacylglycerol

TLR

Toll-like receptor

UPR

Unfolded protein response

WAT

White adipose tissue

XBP1

X box binding protein 1

Notes

Acknowledgements

The authors would like to thank A. Tall, Columbia University, New York, NY, USA, for his advice and help on experimental design and manuscript writing.

Funding

DA is supported by the National Natural Science Foundation of China (Nos 81322006 and 81370396). YZ is supported by the Major National Basic Research Grant of China (No. 2010CB912504). MW is supported by The Netherlands Organization of Scientific Research (NWO VENI – grant 916.11.072).

Duality of interest

The authors declare that there is no duality of interest associated with this manuscript.

Contribution statement

HJ contributed to the concept and design, data acquisition, analysis and interpretation and drafting of the article. MW contributed to the concept and design, data acquisition and revision of the article. CW and YZ contributed to the data acquisition and analysis and revision of the article. DA contributed to the concept and design, data acquisition, analysis and interpretation of data and revision of the article. DA is the guarantor of the work. All authors approved the final version.

Supplementary material

125_2014_3350_MOESM1_ESM.pdf (163 kb)
ESM Fig. 1 (PDF 163 kb)
125_2014_3350_MOESM2_ESM.pdf (367 kb)
ESM Fig. 2 (PDF 366 kb)
125_2014_3350_MOESM3_ESM.pdf (86 kb)
ESM Methods (PDF 86 kb)

References

  1. 1.
    Hotamisligil GS, Shargill NS, Spiegelman BM (1993) Adipose expression of tumor necrosis factor-alpha: direct role in obesity-linked insulin resistance. Science 259:87–91PubMedCrossRefGoogle Scholar
  2. 2.
    Flegal KM, Graubard BI, Williamson DF, Gail MH (2007) Cause-specific excess deaths associated with underweight, overweight, and obesity. JAMA 298:2028–2037PubMedCrossRefGoogle Scholar
  3. 3.
    Ozcan U, Cao Q, Yilmaz E et al (2004) Endoplasmic reticulum stress links obesity, insulin action, and type 2 diabetes. Science 306:457–461PubMedCrossRefGoogle Scholar
  4. 4.
    Park SW, Zhou Y, Lee J et al (2010) The regulatory subunits of PI3K, p85alpha and p85beta, interact with XBP-1 and increase its nuclear translocation. Nat Med 16:429–437PubMedCrossRefPubMedCentralGoogle Scholar
  5. 5.
    Ozcan L, Ergin AS, Lu A et al (2009) Endoplasmic reticulum stress plays a central role in development of leptin resistance. Cell Metab 9:35–51PubMedCrossRefGoogle Scholar
  6. 6.
    Obstfeld AE, Sugaru E, Thearle M et al (2010) C-C chemokine receptor 2 (CCR2) regulates the hepatic recruitment of myeloid cells that promote obesity-induced hepatic steatosis. Diabetes 59:916–925PubMedCrossRefPubMedCentralGoogle Scholar
  7. 7.
    Qatanani M, Lazar MA (2007) Mechanisms of obesity-associated insulin resistance: many choices on the menu. Genes Dev 21:1443–1455PubMedCrossRefGoogle Scholar
  8. 8.
    Weisberg SP, McCann D, Desai M, Rosenbaum M, Leibel RL, Ferrante AW Jr (2003) Obesity is associated with macrophage accumulation in adipose tissue. J Clin Invest 112:1796–1808PubMedCrossRefPubMedCentralGoogle Scholar
  9. 9.
    Han MS, Jung DY, Morel C et al (2013) JNK expression by macrophages promotes obesity-induced insulin resistance and inflammation. Science 339:218–222PubMedCrossRefGoogle Scholar
  10. 10.
    Solinas G, Vilcu C, Neels JG et al (2007) JNK1 in hematopoietically derived cells contributes to diet-induced inflammation and insulin resistance without affecting obesity. Cell Metab 6:386–397PubMedCrossRefGoogle Scholar
  11. 11.
    Boden G (2002) Interaction between free fatty acids and glucose metabolism. Curr Opin Clin Nutr Metab Care 5:545–549PubMedCrossRefGoogle Scholar
  12. 12.
    Nguyen MT, Favelyukis S, Nguyen AK et al (2007) A subpopulation of macrophages infiltrates hypertrophic adipose tissue and is activated by free fatty acids via Toll-like receptors 2 and 4 and JNK-dependent pathways. J Biol Chem 282:35279–35292PubMedCrossRefGoogle Scholar
  13. 13.
    Seimon TA, Nadolski MJ, Liao X et al (2010) Atherogenic lipids and lipoproteins trigger CD36-TLR2-dependent apoptosis in macrophages undergoing endoplasmic reticulum stress. Cell Metab 12:467–482PubMedCrossRefPubMedCentralGoogle Scholar
  14. 14.
    Erbay E, Babaev VR, Mayers JR et al (2009) Reducing endoplasmic reticulum stress through a macrophage lipid chaperone alleviates atherosclerosis. Nat Med 15:1383–1391PubMedCrossRefPubMedCentralGoogle Scholar
  15. 15.
    Kapahi P, Chen D, Rogers AN et al (2010) With TOR, less is more: a key role for the conserved nutrient-sensing TOR pathway in aging. Cell Metab 11:453–465PubMedCrossRefPubMedCentralGoogle Scholar
  16. 16.
    Wullschleger S, Loewith R, Hall MN (2006) TOR signaling in growth and metabolism. Cell 124:471–484PubMedCrossRefGoogle Scholar
  17. 17.
    Ozcan U, Ozcan L, Yilmaz E et al (2008) Loss of the tuberous sclerosis complex tumor suppressors triggers the unfolded protein response to regulate insulin signaling and apoptosis. Mol Cell 29:541–551PubMedCrossRefPubMedCentralGoogle Scholar
  18. 18.
    Ai D, Baez JM, Jiang H et al (2012) Activation of ER stress and mTORC1 suppresses hepatic sortilin-1 levels in obese mice. J Clin Invest 122:1677–1687PubMedCrossRefPubMedCentralGoogle Scholar
  19. 19.
    Hotamisligil GS (2010) Endoplasmic reticulum stress and the inflammatory basis of metabolic disease. Cell 140:900–917PubMedCrossRefPubMedCentralGoogle Scholar
  20. 20.
    Jakubzick C, Bogunovic M, Bonito AJ, Kuan EL, Merad M, Randolph GJ (2008) Lymph-migrating, tissue-derived dendritic cells are minor constituents within steady-state lymph nodes. J Exp Med 205:2839–2850PubMedCrossRefPubMedCentralGoogle Scholar
  21. 21.
    Manning BD (2004) Balancing Akt with S6K: implications for both metabolic diseases and tumorigenesis. J Cell Biol 167:399–403PubMedCrossRefPubMedCentralGoogle Scholar
  22. 22.
    Tremblay F, Brule S, Hee Um S et al (2007) Identification of IRS-1 Ser-1101 as a target of S6K1 in nutrient- and obesity-induced insulin resistance. Proc Natl Acad Sci U S A 104:14056–14061PubMedCrossRefPubMedCentralGoogle Scholar
  23. 23.
    Lumeng CN, Bodzin JL, Saltiel AR (2007) Obesity induces a phenotypic switch in adipose tissue macrophage polarization. J Clin Invest 117:175–184PubMedCrossRefPubMedCentralGoogle Scholar
  24. 24.
    Byles V, Covarrubias AJ, Ben-Sahra I et al (2013) The TSC-mTOR pathway regulates macrophage polarization. Nat Commun 4:2834PubMedCrossRefGoogle Scholar
  25. 25.
    Zhang HH, Lipovsky AI, Dibble CC, Sahin M, Manning BD (2006) S6K1 regulates GSK3 under conditions of mTOR-dependent feedback inhibition of Akt. Mol Cell 24:185–197PubMedCrossRefPubMedCentralGoogle Scholar
  26. 26.
    Kim JK (2006) Fat uses a TOLL-road to connect inflammation and diabetes. Cell Metab 4:417–419PubMedCrossRefGoogle Scholar
  27. 27.
    Shi H, Kokoeva MV, Inouye K, Tzameli I, Yin H, Flier JS (2006) TLR4 links innate immunity and fatty acid-induced insulin resistance. J Clin Invest 116:3015–3025PubMedCrossRefPubMedCentralGoogle Scholar
  28. 28.
    Sabio G, Davis RJ (2010) cJun NH2-terminal kinase 1 (JNK1): roles in metabolic regulation of insulin resistance. Trends Biochem Sci 35:490–496PubMedCrossRefPubMedCentralGoogle Scholar
  29. 29.
    Laplante M, Sabatini DM (2009) mTOR signaling at a glance. J Cell Sci 122:3589–3594PubMedCrossRefPubMedCentralGoogle Scholar
  30. 30.
    Weichhart T, Costantino G, Poglitsch M et al (2008) The TSC-mTOR signaling pathway regulates the innate inflammatory response. Immunity 29:565–577PubMedCrossRefGoogle Scholar
  31. 31.
    Weichhart T, Haidinger M, Katholnig K et al (2011) Inhibition of mTOR blocks the anti-inflammatory effects of glucocorticoids in myeloid immune cells. Blood 117:4273–4283PubMedCrossRefGoogle Scholar
  32. 32.
    Katholnig K, Kaltenecker CC, Hayakawa H et al (2013) p38alpha senses environmental stress to control innate immune responses via mechanistic target of rapamycin. J Immunol 190:1519–1527PubMedCrossRefPubMedCentralGoogle Scholar
  33. 33.
    Weichhart T, Saemann MD (2009) The multiple facets of mTOR in immunity. Trends Immunol 30:218–226PubMedCrossRefGoogle Scholar
  34. 34.
    Sarbassov DD, Ali SM, Sengupta S et al (2006) Prolonged rapamycin treatment inhibits mTORC2 assembly and Akt/PKB. Mol Cell 22:159–168PubMedCrossRefGoogle Scholar
  35. 35.
    Hu P, Han Z, Couvillon AD, Kaufman RJ, Exton JH (2006) Autocrine tumor necrosis factor alpha links endoplasmic reticulum stress to the membrane death receptor pathway through IRE1alpha-mediated NF-kappaB activation and down-regulation of TRAF2 expression. Mol Cell Biol 26:3071–3084PubMedCrossRefPubMedCentralGoogle Scholar
  36. 36.
    Kato H, Nakajima S, Saito Y, Takahashi S, Katoh R, Kitamura M (2012) mTORC1 serves ER stress-triggered apoptosis via selective activation of the IRE1-JNK pathway. Cell Death Differ 19:310–320PubMedCrossRefPubMedCentralGoogle Scholar
  37. 37.
    Hetz C, Bernasconi P, Fisher J et al (2006) Proapoptotic BAX and BAK modulate the unfolded protein response by a direct interaction with IRE1alpha. Science 312:572–576PubMedCrossRefGoogle Scholar
  38. 38.
    Gardai SJ, Hildeman DA, Frankel SK et al (2004) Phosphorylation of Bax Ser184 by Akt regulates its activity and apoptosis in neutrophils. J Biol Chem 279:21085–21095PubMedCrossRefGoogle Scholar
  39. 39.
    Zeng L, Liu YP, Sha H, Chen H, Qi L, Smith JA (2010) XBP-1 couples endoplasmic reticulum stress to augmented IFN-beta induction via a cis-acting enhancer in macrophages. J Immunol 185:2324–2330PubMedCrossRefPubMedCentralGoogle Scholar
  40. 40.
    Martinon F, Chen X, Lee AH, Glimcher LH (2010) TLR activation of the transcription factor XBP1 regulates innate immune responses in macrophages. Nat Immunol 11:411–418PubMedCrossRefPubMedCentralGoogle Scholar
  41. 41.
    Chen WQ, Zhong L, Zhang L et al (2009) Oral rapamycin attenuates inflammation and enhances stability of atherosclerotic plaques in rabbits independent of serum lipid levels. Br J Pharmacol 156:941–951PubMedCrossRefPubMedCentralGoogle Scholar
  42. 42.
    Lamming DW, Ye L, Katajisto P et al (2012) Rapamycin-induced insulin resistance is mediated by mTORC2 loss and uncoupled from longevity. Science 335:1638–1643PubMedCrossRefPubMedCentralGoogle Scholar
  43. 43.
    Ai D, Chen C, Han S et al (2012) Regulation of hepatic LDL receptors by mTORC1 and PCSK9 in mice. J Clin Invest 122:1262–1270PubMedCrossRefPubMedCentralGoogle Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 2014

Authors and Affiliations

  • Hongfeng Jiang
    • 1
  • Marit Westerterp
    • 1
    • 2
  • Chunjiong Wang
    • 3
  • Yi Zhu
    • 3
  • Ding Ai
    • 1
    • 3
    Email author
  1. 1.Division of Molecular Medicine, Department of MedicineColumbia UniversityNew YorkUSA
  2. 2.Department of Medical Biochemistry, Academic Medical CenterUniversity of AmsterdamAmsterdamThe Netherlands
  3. 3.Department of Physiology and PathophysiologyTianjin Medical UniversityTianjinPeople’s Republic of China

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