Hypoxia-inducible factor (HIF) 1α is a metabolic regulator that plays an important role in immunologic responses. Previous studies have demonstrated that HIF1α participates in the M1 polarization of macrophages. To clarify the mechanism of HIF1α-induced polarization of M1 macrophage, myeloid-specific HIF1α overexpression (Lysm HIF1α lsl) mice were employed and the bone marrow-derived and peritoneal macrophages were isolated. RT-PCR results revealed that HIF1α overexpression macrophage had a hyperinflammatory state characterized by the upregulation of M1 markers. Cellular bioenergetics analysis showed lower cellular oxygen consumption rates in the Lysm HIF1α lsl mice. Metabolomics studies showed that HIF1α overexpression led to increased glycolysis and pentose phosphate pathway intermediates. Further results revealed that macrophage M1 polarization, induced by HIF1α overexpression, was via upregulating the mRNA expression of the genes related to the glycolysis metabolism. Our results indicate that HIF1α promoted macrophage glycolysis metabolism, which induced M1 polarization in mice.
National Key Research and Development Program of China2016YFC0903100National Natural Science Foundation of China814705548152200791439206312300351. Introduction
Macrophages are the main component of innate immunity and play important roles in various inflammatory diseases, including hepatitis, vascular diseases, inflammatory bowel diseases, rheumatoid arthritis, and airway inflammation [1–5]. Activated macrophages are commonly divided into two polarized phenotypes, classically activated M1 and alternatively activated M2. Macrophages activated by interferon γ or toll-like receptor agonists polarize to the M1 phenotype [6], which are proinflammatory macrophages and play a central role in the host’s defense against infection and inflammatory diseases [7, 8]. Macrophages activated by Th2 cytokines, IL-4, and IL-13 are polarized to M2 phenotype, which are associated with inflammation relief and tissue remodeling [9, 10]. Macrophage activation can be altered by disrupting cellular energy metabolism [11, 12]. Recent studies have demonstrated that M1 macrophages demand glycolysis, while M2 macrophages require fatty acid oxidation [13, 14]. However, the metabolomics profiling and the metabolic mechanism of macrophages polarization remained undefined.
Hypoxia-inducible factor 1 (HIF1) has emerged as one of the central regulators of inflammation mediated by myeloid cells [15, 16]. HIF1 is an α and β heterodimer [15, 17]. Whereas HIF1β is constitutively expressed in cells regardless of O2 tension [18], HIF1α protein increases exponentially in response to reduced O2 concentration [19]. HIF1 has displayed a significant role in regulating cellular ATP concentration and myeloid cell function including cell aggregation, motility, invasiveness, and bacterial killing [20–22]. Importantly, it has been reported that HIF1 participates in the regulation of macrophage polarization [20]. As glucose metabolism determines polarization of macrophages [23, 24], whether glucose metabolism is involved in HIF1α-induced macrophage polarization process has remained unclear.
2. Materials and Methods2.1. Chemicals and Reagents
RPMI 1640 medium was purchased from Gibco. Fetal Bovine Serum (FBS), penicillin, and streptomycin were purchased from HyClone. GM-CSF was purchased from PeproTech. Ammonium acetate, LPS, oligomycin, carbonyl cyanide p-trifluoromethoxyphenylhydrazone (FCCP), rotenone, and antimycin A were purchased from Sigma. BBL™ Thioglycollate Medium was purchased from BD Biosciences, US. [5-13C]glutamine was obtained from Cambridge Isotope Laboratories. HPLC grade ammonium hydroxide, acetonitrile, and methanol were purchased from Fisher Scientific. Deionized water was produced by a Milli-Q system.
2.2. Animals
Lsl-HIF1 dPA mice were obtained as described previously [25]. For myeloid-specific HIF1α overexpression, Lsl-HIF1 dPA mice were crossed with mice harboring the Cre recombinase under control of the lysozyme M (Lysm) promoter, which is found only in myeloid lineage cells, to obtain the Lysm HIF1α lsl mice. The wild-type (WT) and Lysm HIF1α lsl mice were littermate and on a C57BL/6 J background, after backcrossing with C57BL/6J mice for over ten generations. All the animal protocols were approved by the Animal Care and Use Committee of Peking University.
2.3. Peritoneal Macrophage
WT and Lysm HIF1α lsl mice (6- to 8-weeks old) were injected intraperitoneally with 4% thioglycollate solution (2 ml). Three days later, peritoneal cells were harvested by injecting the peritoneal cavity with PBS containing 10% FBS. Primary peritoneal macrophages were cultured with RPMI-1640 medium supplemented with 10% FBS. Medium was changed 2–4 h later. Thioglycollate-elicited peritoneal macrophages were attached on plates and continued culturing for 6 to 24 h.
2.4. Bone Marrow-Derived Macrophages (BMDMs)
Bone marrow cells were collected from WT and Lysm HIF1α lsl mice (4- to 6-weeks old). Adherent macrophages were cultured for 3 days in RPMI-1640 supplemented with 10% FBS and GM-CSF (10 ng/mL). Then, the medium was changed and the attached macrophages were obtained after another 3 days. To obtain the M1 polarization, macrophages were continued culturing for 2 days in RPMI-1640 supplemented with 10% FBS and LPS (10 ng/mL).
2.5. Quantitative RT-PCR
Total RNA was isolated from peritoneal macrophages or BMDMs using TRIzol reagent. cDNA was obtained using the M-MLV reverse transcriptase kit according to the manufacturer’s instructions. RT-PCR amplification was performed using an Mx3000 Multiplex Quantitative PCR System and SYBR Green I reagent. Gene expression levels were normalized to the internal control 18S rRNA.
2.6. Extracellular Flux Analysis
An XF24 Extracellular Flux Analyzer was used to measure the respiratory conditions of murine peritoneal macrophages. Cells were plated at 5 × 104 cells/well in 24-well XF microplates and cultured for 6 h. RPMI-1640 medium was replaced with XF base medium supplemented with 25 mM glucose and 2 mM pyruvate. After 1 h of incubation in a CO2-free incubator at 37°C, the oxygen consumption rate (OCR) and extracellular acidification rates (ECAR) were measured following the manufacturer’s instruction. Mitochondrial stress tests were performed under basal conditions or with the treatment of metabolic reagents, including 1 mM oligomycin, 1 mM FCCP, 1 mM rotenone, and 1 mM antimycin A. ECAR was calculated by Wave software.
2.7. Metabolomics Analysis
Analysis of metabolites was performed with a liquid chromatography-tandem mass spectrometry. For metabolite extraction, cultured cells were washed with saline twice, lysed in 80% aqueous methanol (v/v), and equilibrated at −80°C for 20 min. [5-13C]glutamine was added as an internal standard. Cells were oscillated for 10 min and centrifuged with the speed of 14,000g for 10 min at 4°C. Cell supernatants of metabolite extracts were collected, dried, and stored at −80°C before injection.
For liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis, samples were reconstituted in water and analyzed using a QTRAP 5500 LC-MS/MS system (AB SCIEX) coupled with an ACQUITY UHPLC System (Waters Corporation). An Xbridge Amide column (100 × 4.6 mm i.d., 3.5 Lm; Waters Corporation) was employed for compound separation at 30°C. The mobile phase A was 5 mM ammonium acetate in water with 5% acetonitrile, and mobile phase B was acetonitrile. The linear gradient used was as follows: 0 min, 90% B; 1.5 min, 85% B; 5.5 min, 35% B; 10 min, 35% B; 10.5 min, 35% B; 14.5 min, 35% B; 15 min, 85% B; and 20 min, 85% B. The flow rate was 0.5 ml/min. MultiQuant v3.0 software (AB SCIEX) was used to process all raw liquid chromatography-mass spectrometry data and integrate chromatographic peaks. Integrated peak areas corresponding to metabolite concentrations were further analyzed using the MetaboAnalyst website (http://www.metaboanalyst.ca). Metabolite abundance was expressed relative to the internal standard.
2.8. Statistical Analysis
All data are presented as the mean ± SEM. Comparisons of data sets were performed using unpaired Student’s t-tests for comparing two groups. Statistical analyses were performed using GraphPad Prism (GraphPad Software). A P value at ∗P<0.05 and ∗∗P<0.01 was considered statistically significant for all experiments.
3. Results3.1. HIF1α Induced M1 Polarization of Macrophages
In this study, we used Lysm HIF1α lsl mice and WT mice to testify whether HIF1α in macrophages affects macrophage polarization as previously reported [20]. The mRNA level of Hif1α in bone marrow-derived macrophages (BMDMs) and peritoneal macrophages was confirmed by RT-PCR, displaying approximately threefolds of Hif1α expression compared with the WT mice (Figure 1(a)). Then, we examined the relative mRNA levels of M1 and M2 markers in peritoneal macrophages and BMDMs. The mRNA expressions of M1 markers, including Il6, Il1b, Inos, Tnfα, and Cd11c, were markedly higher in peritoneal macrophages isolated from Lysm HIF1α lsl mice, while the expressions of M2 markers, Arg1, Cd206, and Chi313, showed little difference or even lower compared with WT mice at 6 h (Figure 1(b)) and 24 h (Figure 1(c)). In BMDMs, M1 markers were highly expressed in Lysm HIF1α lsl mice, and the M2 markers were markedly less at the same level by comparison (Figure 1(d)). These results indicate that macrophage HIF1α overexpression induces M1 polarization of macrophages.
HIF1α induced M1 polarization of macrophages. (a) The relative mRNA level of HIF1α in the BMDMs and peritoneal macrophages of WT mice and Lysm Hif1α lsl mice. (b) The relative mRNA levels of M1 and M2 markers in the peritoneal macrophages isolated from WT mice and Lysm HIF1α lsl mice for 6 h. (c) The relative mRNA levels of M1 and M2 markers in the peritoneal macrophages isolated from WT mice and Lysm HIF1α lsl mice for 24 h. (d) The relative mRNA levels of M1 and M2 markers in the BMDMs isolated from the WT mice and Lysm HIF1α lsl mice with the treatment of LPS for 48 h. For each gene, mRNA level was normalized to the level of 18S rRNA expression. Statistical comparisons were made using two-tailed Student’s t-test (a, b, c, and d). ∗P<0.05 and ∗∗P<0.01, compared with WT mice. All values were presented as mean ± SEM for n=3–5 independent experiments in each group.
3.2. HIF1α Decreased Mitochondrial Oxidation and Promoted Glycolysis Metabolism in Macrophages
Recent studies have indicated that the activation of macrophage polarization was marked by their metabolic programs [23, 24]. Therefore, mitochondrial oxidation was detected in peritoneal macrophages isolated from WT mice and Lysm HIF1α lsl mice. HIF1α overexpressed macrophages displayed a marked lower mitochondrial oxygen consumption rate (OCR) (Figure 2(a)) but a higher extracellular acidification rates (ECAR) (Figure 2(b)), suggesting the promotion of glycolysis metabolism. With the treatment of mitochondrial oxidative inhibitors, including carbonyl cyanide p-trifluoromethoxyphenylhydrazone (FCCP), oligomycin, antimycin A, and rotenone, the ratio of mitochondrial oxidation to glycolysis metabolism was decreased in HIF1α overexpression macrophages (Figure 2(c)). These data indicate that decreased mitochondrial oxidation and increased glycolysis metabolism are induced by HIF1α in macrophages.
HIF1α decreased mitochondrial oxidation and promotes glycolysis metabolism in macrophages. (a and b) Metabolic respiratory parameters of peritoneal macrophages isolated from the WT mice and Lysm HIF1α lsl mice were measured with the treatment of extracellular flux analyzer: A, oligomycin; B, carbonyl cyanide p-trifluoromethoxyphenylhydrazone (FCCP); C, antimycin A and rotenone. (a) The oxygen consumption rate (OCR) value was measured at the basal level and after the treatment of A, B, and C quantitated on the right panel. Basal OCR was measured before the injection of a, and maximal OCR was calculated by subtracting the nonmitochondrial OCR from the peak OCR after the treatment of B. (b) The extracellular acidification rate (ECAR) value was calculated by the software. (c) The OCR/ECAR ratio was calculated at basal level quantitated on the right panel. Statistical comparisons were made using two-tailed Student’s t-test (a and c). ∗∗P<0.01 compared with WT mice. All values were presented as mean ± SEM for n=9–15 independent experiments in each group.
3.3. Metabolomics Analysis Showed That HIF1α-Induced Glycolysis Metabolism and Pentose Phosphate Pathway and Decreased Mitochondrial Oxidation
The extracellular flux analysis results revealed the different metabolic mode between macrophages isolated from Lysm HIF1α lsl mice and WT mice. To further explore the detailed changes in metabolic profiling, metabolites were extracted from peritoneal macrophages isolated from Lysm HIF1α lsl mice and WT mice and analyzed using LC-MS/MS. The heatmap generated from hierarchical clustering and a partial least squares discriminant analysis (PLS-DA) plot of metabolites revealed a distinct metabolic profile in macrophages isolated from Lysm HIF1α lsl mice and WT mice (Figures 3(a), 3(b), and 3(c)). VIP scores extracted from the PLS-DA model demonstrated that glycolytic intermediates got relative high VIP scores (Figure 3(d)). Enrichment analysis and pathway analysis showed an apparent disparity in the glycolysis, TCA cycle, and pentose phosphate pathway (Figures 3(e) and 3(f)). Histogram analysis exhibited that the metabolite levels were increased in the glycolysis, including lactate, GADP, G-3-P, 3-PG, 2,3-DPG, FBP, G-6-P, F-6-P, PEP, and BPG (Figure 3(g)), and decreased in mitochondrial oxidation, including fumarate, succinate, citrate, and isocitrate (Figure 3(h)) in Lysm HIF1α lsl mice. Besides, the pentose phosphate pathway, a shunt from the glycolytic pathway, was also activated proved by the increase of d-erythrose-4-phosphate, xylulose-5-phosphate, sedoheptulose-7-phosphate, ribose-5-phosphate, and NADPH levels (Figure 3(i)). The activated pentose phosphate pathway is assumed to provide biosynthetic substrates to support macrophage growth and activation. Thus, metabolomics analysis showed an enhancement of glycolysis metabolism and pentose phosphate pathway but a decreased mitochondrial oxidation in HIF1α overexpressed macrophages.
Metabolomics analysis of HIF1α-modified macrophage glycolysis metabolism. (a, b, c, d, e, and f) Peritoneal macrophages were isolated from the WT and Lysm HIF1α lsl mice. An LC-MS/MS system was used to measure the abundance of cellular metabolites. Metabolomics data were analyzed using the MetaboAnalyst website. (a) Heatmap of the intracellular metabolites generated from hierarchical clustering. Red series denoted relative high concentrations and blue series denoted relative low concentrations. (b) 2D PLS-DA score plot. (c) 3D PLS-DA score plot. (d) VIP scores. (e) Overview of metabolite enrichment in HIF1α overexpressed macrophages. (f) Metabolic pathway analysis of HIF1α overexpressed macrophages. (g, h, and i) Relative levels of metabolites in the glycolysis metabolism (g), TCA cycle (h), and pentose phosphate pathways (i). Statistical comparisons were made using two-tailed Student’s t-test (g, h, and i). ∗P<0.05 and ∗∗P<0.01, compared with WT mice. All values were presented as mean ± SEM for n=10–14 independent experiments in each group. FBP: fructose 1,6-bisphosphate; F-6-P: fructose-6-phosphate; GADP: glyceraldehyde-3-phosphate; G-6-P: glucose-6-phosphate; PEP: phosphoenolpyruvate; 3-PG: 3-phosphoglycerate.
3.4. HIF1α-Modified Macrophage Glycolysis Metabolism through Regulation of Glycolytic Gene Expression
The mechanism of the glucose metabolic disparity in HIF1α overexpressed macrophages was explored by analyzing gene expression. mRNA expressions of some glycolytic genes, including Pdk1, Pgk1, Glut1, Gck, and Pkm2, were higher in peritoneal macrophages isolated from the Lysm HIF1α lsl mice than in the WT mice at both 6 h and 24 h (Figures 4(a) and 4(b)). The similar results were observed in BMDMs isolated from WT mice and Lysm HIF1α lsl mice activated to M1 with the treatment of LPS (10 ng/mL) for 48 h (Figure 4(c)).
HIF1α activated macrophage glycolysis metabolism-related genes. (a) Relative mRNA levels of Pdk1, Pgk1, Glut1, Gck, and Pkm2 in the peritoneal macrophages isolated from the WT mice and Lysm HIF1α lsl mice for 6 h. (b) Relative mRNA levels of Pdk1, Pgk1, Glut1, Gck, and Pkm2 in the peritoneal macrophages isolated from WT mice and Lysm HIF1α lsl mice for 24 h. (c) Relative mRNA levels of Pdk1, Pgk1, Glut1, Gck, and Pkm2 in the BMDMs isolated from WT mice and Lysm HIF1α lsl mice activated to M1 with the treatment of LPS for 48 h. For each gene, mRNA level was normalized to the level of 18S rRNA expression. Statistical comparisons were made using two-tailed Student’s t-test. ∗P<0.05 and ∗∗P<0.01, compared with WT mice. All values were presented as mean ± SEM for n=3–5 independent experiments in each group.
4. Discussion
The liver is a site particularly enriched with innate immune cells [26] and the largest metabolic organ in the body that is responsible for various metabolic processes regulating various functions [27, 28]. Innate immune cells modify and disrupt critical processes implicated in metabolic disease. Meanwhile, metabolic stress initiates a feed-forward cycle of inflammatory responses [29]. Given that HIF1α is a metabolic regulator playing important roles in inflammation [30, 31], we investigated whether the regulation of cellular metabolism by HIF1α controls macrophage polarization and inflammation.
Our study first used HIF1α overexpression mice to validate the previous report that HIF1α promoted the accumulation of M1 macrophages [32–34]. Gene expression profiling of macrophages revealed an increase in markers of M1 macrophages and decreased or unchanged expression of M2 macrophage markers (Figure 1), supporting that HIF1 triggers macrophage polarizing to the M1 phenotype.
Recent findings suggest that cellular metabolism plays an important role during macrophage polarization [23, 35]. Classically activated macrophages secret proinflammatory mediators, accompanied with a shift from mitochondrial oxidation toward glycolysis metabolism [36]. On the contrast, alternatively activated macrophages secrete anti-inflammatory cytokines and declare an increased demand of fatty-acid oxidation [37]. Consistent with these findings, we showed that HIF1α overexpressed macrophages reduced cellular OCR and increased ECAR (Figure 2). The OCR/ECAR ratio was also dramatically decreased, reflecting a preference of glycolysis metabolism compared with mitochondrial oxidation in HIF1α overexpressed macrophages.
Macrophages are capable of coordinating their metabolic programs to adjust their immunological and bioenergetic functional properties. In our study, metabolomics profiling analysis witnessed a splendid disparation of metabolites from peritoneal macrophages isolated from WT mice and Lysm HIF1α lsl mice (Figure 3). Relative concentration of metabolites further demonstrated that HIF1 induced activation of glycolysis metabolism and pentose phosphate pathway and inhibited mitochondrial oxidation in macrophages in Lysm HIF1α lsl mice (Figure 3). Pentose phosphate pathway utilizes glucose to generate NADPH for nucleotide biosynthesis, supporting the production of reduced glutathione and therefore limits oxidative stress in M1 macrophages [38, 39]. Increased levels of pentose phosphate pathway metabolic intermediates satisfy the substrates need in HIF1α-prompted macrophage growth and proliferation. These data are consistent with previous studies [23, 24, 37] and lend further support to the notion that glycolysis metabolism is essential to the activation of inflammatory macrophages.
LPS-treated BMDMs were reported to tend to engage an HIF1α-dependent transcriptional program that is responsible for heightened glycolysis [40]. Metabolic mechanisms in HIF1α-deficient mice were reported to be accompanied with abolished glycolysis, decreased hepatic glucose output, and elevated gluconeogenesis [41]. On the contrast, in our study, HIF1α overexpression in the macrophages was accompanied with high mRNA levels of Pdk1, Pgk1, Glut1, Gck, and Pkm2 (Figure 4), which was responsible for activated glycolysis. Heightened glycolysis may guarantee a competitive bioenergetic state and intensive energy for M1 macrophage polarization and also provide precursors for the production and secretion of proinflammatory cytokines [39, 42]. This process indicates the role of HIF1α in potential coordination between metabolic regulation and macrophage physiology.
5. Conclusions
In summary, we demonstrated that HIF1α activation elevates glycolysis metabolism and further induces M1 polarization of macrophages.
Conflicts of Interest
The authors declare there are no conflicts of interest.
Authors’ Contributions
Ting Wang and Huiying Liu contributed equally to this work.
Acknowledgments
This work was supported by the National Natural Science Foundation of China (nos. 81470554 and 81522007 to Changtao Jiang and 91439206 and 31230035 to Xian Wang) and the National Key Research and Development Program of China (2016YFC0903100).
CursiefenC.ChenL.BorgesL. P.JacksonD.CaoJ.RadziejewskiC.D’AmoreP. A.DanaM. R.WiegandS. J.StreileinJ. W.VEGF-A stimulates lymphangiogenesis and hemangiogenesis in inflammatory neovascularization via macrophage recruitment20041137104010501505731110.1172/JCI20465MantovaniA.SozzaniS.LocatiM.AllavenaP.SicaA.Macrophage polarization: tumor-associated macrophages as a paradigm for polarized M2 mononuclear phagocytes2002231154955512401408MooreK. J.SheedyF. J.FisherE. A.Macrophages in atherosclerosis: a dynamic balance201313107097212399562610.1038/nri35202-s2.0-84886797808KinneR. W.BrauerR.StuhlmullerB.Palombo-KinneE.BurmesterG. R.Macrophages in rheumatoid arthritis20002318920210.1186/ar862-s2.0-0034469464CareauE.BissonnetteE. Y.Adoptive transfer of alveolar macrophages abrogates bronchial hyperresponsiveness200431122271496297410.1165/rcmb.2003-0229OC2-s2.0-3042757394Palsson-McDermottE. M.CurtisA. M.GoelG.LauterbachM. A.SheedyF. J.GleesonL. E.van den BoschM. W.QuinnS. R.Domingo-FernandezR.JohnstonD. G.JiangJ. K.IsraelsenW. J.KeaneJ.ThomasC.ClishC.Vander HeidenM.XavierR. J.O'NeillL. A.Pyruvate kinase M2 regulates Hif-1α activity and IL-1β induction and is a critical determinant of the Warburg effect in LPS-activated macrophages201521165802556520610.1016/j.cmet.2014.12.0052-s2.0-84920591180SicaA.BronteV.Altered macrophage differentiation and immune dysfunction in tumor development20071175115511661747634510.1172/JCI314222-s2.0-34248172324DoedensA. L.StockmannC.RubinsteinM. P.LiaoD.ZhangN.DeNardoD. G.CoussensL. M.KarinM.GoldrathA. W.JohnsonR. S.Macrophage expression of hypoxia-inducible factor-1α suppresses T-cell function and promotes tumor progression20107019746574752084147310.1158/0008-5472.CAN-10-14392-s2.0-77957350018PauleauA. L.RutschmanR.LangR.PernisA.WatowichS. S.MurrayP. J.Enhancer-mediated control of macrophage-specific arginase I expression2004172127565757315187136TanZ.XieN.CuiH.MoelleringD. R.AbrahamE.ThannickalV. J.LiuG.Pyruvate dehydrogenase kinase 1 participates in macrophage polarization via regulating glucose metabolism201519412608260892596448710.4049/jimmunol.14024692-s2.0-84931386872BruickR. K.McKnightS. L.A conserved family of prolyl-4-hydroxylases that modify HIF20012945545133713401159826810.1126/science.10663732-s2.0-0035834409MurdochC.GiannoudisA.LewisC. E.Mechanisms regulating the recruitment of macrophages into hypoxic areas of tumors and other ischemic tissues20041048222422341523157810.1182/blood-2004-03-11092-s2.0-4944244259TannahillG. M.CurtisA. M.AdamikJ.Palsson-McDermottE. M.McGettrickA. F.GoelG.FrezzaC.BernardN. J.KellyB.FoleyN. H.ZhengL.GardetA.TongZ.JanyS. S.CorrS. C.HaneklausM.CaffreyB. E.PierceK.WalmsleyS.BeasleyF. C.CumminsE.NizetV.WhyteM.TaylorC. T.LinH.MastersS. L.GottliebE.KellyV. P.ClishC.AuronP. E.XavierR. J.O'NeillL. A.Succinate is an inflammatory signal that induces IL-1β through HIF-1α201349674442382422353559510.1038/nature119862-s2.0-84876285741GubserP. M.BantugG. R.RazikL.FischerM.DimeloeS.HoengerG.DurovicB.JauchA.HessC.Rapid effector function of memory CD8+ T cells requires an immediate-early glycolytic switch20131410106410722395566110.1038/ni.26872-s2.0-84886721392WangG. L.JiangB. H.RueE. A.SemenzaG. L.Hypoxia-inducible factor 1 is a basic-helix-loop-helix-PAS heterodimer regulated by cellular O2 tension19959212551055147539918CramerT.YamanishiY.ClausenB. E.FörsterI.PawlinskiR.MackmanN.HaaseV. H.JaenischR.CorrM.NizetV.FiresteinG. S.GerberH. P.FerraraN.JohnsonR. S.HIF-1α is essential for myeloid cell-mediated inflammation2003112564565712628185KaelinW. G.Jr.RatcliffeP. J.Oxygen sensing by metazoans: the central role of the HIF hydroxylase pathway20083043934021849874410.1016/j.molcel.2008.04.0092-s2.0-43649093915HeQ.GaoZ.YinJ.ZhangJ.YunZ.YeJ.Regulation of HIF-1α activity in adipose tissue by obesity-associated factors: adipogenesis, insulin, and hypoxia20113005E877E8852134354210.1152/ajpendo.00626.20102-s2.0-79955561312WeidemannA.JohnsonR. S.Biology of HIF-1α20081546216271825920110.1038/cdd.2008.122-s2.0-40949115368NizetV.JohnsonR. S.Interdependence of hypoxic and innate immune responses2009996096171970441710.1038/nri26072-s2.0-70249099576LewisJ. S.LeeJ. A.UnderwoodJ. C.HarrisA. L.LewisC. E.Macrophage responses to hypoxia: relevance to disease mechanisms199966688990010614769LeeK. Y.GestaS.BoucherJ.WangX. L.KahnC. R.The differential role of Hif1β/Arnt and the hypoxic response in adipose function, fibrosis, and inflammation20111444915032198270910.1016/j.cmet.2011.08.0062-s2.0-80053894264KellyB.O'NeillL. A.Metabolic reprogramming in macrophages and dendritic cells in innate immunity20152577717842604516310.1038/cr.2015.682-s2.0-84942982260O'NeillL. A.PearceE. J.Immunometabolism governs dendritic cell and macrophage function2016213115232669497010.1084/jem.201515702-s2.0-84960399221XueX.RamakrishnanS.AndersonE.TaylorM.ZimmermannE. M.SpenceJ. R.HuangS.GreensonJ. K.ShahY. M.Endothelial PAS domain protein 1 activates the inflammatory response in the intestinal epithelium to promote colitis in mice201314548318412386050010.1053/j.gastro.2013.07.0102-s2.0-84884390272SekiS.HabuY.KawamuraT.TakedaK.DobashiH.OhkawaT.HiraideH.The liver as a crucial organ in the first line of host defense: the roles of Kupffer cells, natural killer (NK) cells and NK1.1 Ag+ T cells in T helper 1 immune responses2000174354610807505TackeF.ZimmermannH. W.Macrophage heterogeneity in liver injury and fibrosis2014605109010962441260310.1016/j.jhep.2013.12.0252-s2.0-84898789996TothC. A.ThomasP.Liver endocytosis and Kupffer cells19921612552661319954GordonS.MartinezF. O.Alternative activation of macrophages: mechanism and functions20103255936042051087010.1016/j.immuni.2010.05.0072-s2.0-77953268611ZhangW.PetrovicJ. M.CallaghanD.JonesA.CuiH.HowlettC.StanimirovicD.Evidence that hypoxia-inducible factor-1 (HIF-1) mediates transcriptional activation of interleukin-1β (IL-1β) in astrocyte cultures20061741-263731650430810.1016/j.jneuroim.2006.01.0142-s2.0-33646117271ErtelW.MorrisonM. H.AyalaA.ChaudryI. H.Hypoxemia in the absence of blood loss or significant hypotension causes inflammatory cytokine release19952691, Part 2R160R1667631888TakedaN.O'DeaE. L.DoedensA.KimJ. W.WeidemannA.StockmannC.AsagiriM.SimonM. C.HoffmannA.JohnsonR. S.Differential activation and antagonistic function of HIF-α isoforms in macrophages are essential for NO homeostasis20102454915012019444110.1101/gad.18814102-s2.0-77649177217NishiK.OdaT.TakabuchiS.OdaS.FukudaK.AdachiT.SemenzaG. L.ShinguK.HirotaK.LPS induces hypoxia-inducible factor 1 activation in macrophage-differentiated cells in a reactive oxygen species-dependent manner20081059839951819900310.1089/ars.2007.1825TawakolA.SinghP.MojenaM.Pimentel-SantillanaM.EmamiH.MacNabbM.RuddJ. H.NarulaJ.EnriquezJ. A.TravésP. G.Fernández-VelascoM.BartronsR.Martín-SanzP.FayadZ. A.TejedorA.BoscáL.HIF-1α and PFKFB3 mediate a tight relationship between proinflammatory activation and anerobic metabolism in atherosclerotic macrophages2015356146314712588206510.1161/ATVBAHA.115.3055512-s2.0-84933039838OlefskyJ. M.GlassC. K.Macrophages, inflammation, and insulin resistance2010722192462014867410.1146/annurev-physiol-021909-1358462-s2.0-77951918926WangH. J.HsiehY. J.ChengW. C.LinC. P.LinY. S.YangS. F.ChenC. C.IzumiyaY.YuJ. S.KungH. J.WangW. C.JMJD5 regulates PKM2 nuclear translocation and reprograms HIF-1α-mediated glucose metabolism201411112842434430510.1073/pnas.13112491112-s2.0-84891953688ChawlaA.NguyenK. D.GohY. P.Macrophage-mediated inflammation in metabolic disease201111117387492198406910.1038/nri30712-s2.0-80355133234HaschemiA.KosmaP.GilleL.EvansC. R.BurantC. F.StarklP.KnappB.HaasR.SchmidJ. A.JandlC.AmirS.LubecG.ParkJ.EsterbauerH.BilbanM.BrizuelaL.PospisilikJ. A.OtterbeinL. E.WagnerO.The sedoheptulose kinase CARKL directs macrophage polarization through control of glucose metabolism20121568138262268222210.1016/j.cmet.2012.04.0232-s2.0-84862016400LiuL.LuY.MartinezJ.BiY.LianG.WangT.MilastaS.WangJ.YangM.LiuG.GreenD. R.WangR.Proinflammatory signal suppresses proliferation and shifts macrophage metabolism from Myc-dependent to HIF1α-dependent20161136156415692681145310.1073/pnas.15180001132-s2.0-84957800096ShinM. K.DragerL. F.YaoQ.Bevans-FontiS.YooD. Y.JunJ. C.AjaS.BhanotS.PolotskyV. Y.Metabolic consequences of high-fat diet are attenuated by suppression of HIF-1α2012710, article e465622304970710.1371/journal.pone.00465622-s2.0-84867030992Galvan-PenaS.O'NeillL. A.Metabolic reprograming in macrophage polarization201454202522890210.3389/fimmu.2014.004202-s2.0-84919452312FreemermanA. J.JohnsonA. R.SacksG. N.MilnerJ. J.KirkE. L.TroesterM. A.MacintyreA. N.Goraksha-HicksP.RathmellJ. C.MakowskiL.Metabolic reprogramming of macrophages: glucose transporter 1 (GLUT1)-mediated glucose metabolism drives a proinflammatory phenotype201428911788478962449261510.1074/jbc.M113.5220372-s2.0-84896269174