Abstract
Microglia cells are activated in response to different stress signals. Several metabolic adaptations underlie microglia activation in the brain. Among these, in conditions like ischemic stroke and, hypoxic stress stimuli activate microglia cells. Hypoxic stress is mediated by HIF-1α. Although HIF-1α has been implicated in the alteration of metabolic pathways, changes in microglia lipid metabolism during M1 activation of microglia induced by elevated HIF-1α levels are yet to be understood. This can also merit interest in the development of novel targets to mitigate chronic inflammation. Our study aims to elucidate the transcriptional regulation of metabolic pathways in microglia cells during HIF-1α mediated activation. To study the adaptations in the metabolic pathways we induced microglia activation, by activating HIF-1α. Here, we show that microglia cells activated in response to elevated HIF-1α require ongoing lipogenesis and fatty acid breakdown. Notably, autophagy is activated during the initial stages of microglia activation. Inhibition of autophagy in activated microglia affects their viability and phagocytic activity. Collectively, our study expands the understanding of the molecular link between autophagy, lipid metabolism, and inflammation during HIF-1α mediated microglial activation that can lead to the development of promising strategies for controlling maladaptive activation states of microglia responsible for neuroinflammation. Together, our findings suggest that the role of HIF-1α in regulating metabolic pathways during hypoxia in microglia is beyond optimization of glucose utilization and distinctly regulates lipid metabolism during pro-inflammatory activation.
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References
Ávalos Y, Hernández-Cáceres MP, Lagos P, Pinto-Nuñez D, Rivera P, Burgos P, Díaz-Castro F, Joy-Immediato M, Venegas-Zamora L, Lopez-Gallardo E et al (2022) Palmitic acid control of ciliogenesis modulates insulin signaling in hypothalamic neurons through an autophagy-dependent mechanism. Cell Death Dis 13. https://doi.org/10.1038/s41419-022-05109-9
Bachiller S, Jiménez-Ferrer I, Paulus A, Yang Y, Swanberg M, Deierborg T, Boza-Serrano A (2018) Microglia in neurological diseases: a road map to brain-disease dependent-inflammatory response. Front Cell Neurosci 12
Bellot G, Garcia-Medina R, Gounon P, Chiche J, Roux D, Pouysségur J, Mazure NM (2009) Hypoxia-induced autophagy is mediated through hypoxia-inducible factor induction of BNIP3 and BNIP3L via their BH3 domains. Mol Cell Biol 29:2570–2581. https://doi.org/10.1128/mcb.00166-09
Bidault G, Virtue S, Petkevicius K, Jolin HE, Dugourd A, Guénantin AC, Leggat J, Mahler-Araujo B, Lam BYH, Ma MK et al (2021) SREBP1-induced fatty acid synthesis depletes macrophages antioxidant defences to promote their alternative activation. Nat Metab 3:1150–1162. https://doi.org/10.1038/s42255-021-00440-5
Bok S, Kim YE, Woo Y, Kim S, Kang SJ, Lee Y, Park SK, Weissman IL, Ahn GO (2017) Hypoxia-inducible factor-1a regulates microglial functions affecting neuronal survival in the acute phase of ischemic stroke in mice. Oncotarget 8:111508–111521. https://doi.org/10.18632/oncotarget.22851
Bonilla DL, Bhattacharya A, Sha Y, Xu Y, Xiang Q, Kan A, Jagannath C, Komatsu M, Eissa NT (2013) Autophagy regulates phagocytosis by modulating the expression of scavenger receptors. Immunity 39:537–547. https://doi.org/10.1016/j.immuni.2013.08.026
Burtscher J, Mallet RT, Burtscher M Millet P (2021) Hypoxia and brain aging : neurodegeneration or neuroprotection? 68. https://doi.org/10.1016/j.arr.2021.101343
Chandel NS, Maltepe E, Goldwasser E, Mathieu CE, Simon MC, Schumacker PT (1998) Mitochondrial reactive oxygen species trigger hypoxia-induced transcription. Proc Natl Acad Sci U S A 95:11715–11720. https://doi.org/10.1073/pnas.95.20.11715
Chandel NS, McClintock DS, Feliciano CE, Wood TM, Melendez JA, Rodriguez AM, Schumacker PT (2000) Reactive oxygen species generated at mitochondrial complex III stabilize hypoxia-inducible factor-1α during hypoxia: a mechanism of O2 sensing. J Biol Chem 275:25130–25138. https://doi.org/10.1074/jbc.M001914200
Chen R, Lai UH, Zhu L, Singh A, Ahmed M, Forsyth NR (2018) Reactive oxygen species formation in the brain at different oxygen levels: the role of hypoxia inducible factors. Front Cell Dev Biol 6
Chinetti G, Lestavel S, Remaley A, Neve B, Torra I, Minnich A, Jaye M, Duverger N, Brewer H, Fruchart J et al (2000) PPAR alpha and PPAR gamma activators induce cholesterol removal from human macrophage foam cells through stimulation of the ABC-1 pathway. Circulation 102:311–311
Colville-Nash PR, Qureshi SS, Willis D, Willoughby DA (1998) Inhibition of inducible nitric oxide synthase by peroxisome proliferator-activated receptor agonists: correlation with induction of heme oxygenase 1. J Immunol 161:978–984. https://doi.org/10.4049/jimmunol.161.2.978
Dragano NR, Monfort-Pires M, Velloso LA (2020) Mechanisms mediating the actions of fatty acids in the hypothalamus. Neuroscience 447:15–27
Halder SK, Milner R (2020) Mild hypoxia triggers transient blood–brain barrier disruption: a fundamental protective role for microglia. Acta Neuropathol Commun 8. https://doi.org/10.1186/s40478-020-01051-z
Harris J, Hartman M, Roche C, Zeng SG, O’Shea A, Sharp FA, Lambe EM, Creagh EM, Golenbock DT, Tschopp J et al (2011) Autophagy controls IL-1β secretion by targeting pro-IL-1β for degradation. J Biol Chem 286:9587–9597. https://doi.org/10.1074/jbc.M110.202911
Haynes SE, Hollopeter G, Yang G, Kurpius D, Dailey ME, Gan WB, Julius D (2006) The P2Y12 receptor regulates microglial activation by extracellular nucleotides. Nat Neurosci 9:1512–1519. https://doi.org/10.1038/nn1805
Hegdekar N, Sarkar C, Bustos S, Ritzel RM, Hanscom M, Ravishankar P, Philkana D, Wu J, Loane DJ, Lipinski MM (2023) Inhibition of autophagy in microglia and macrophages exacerbates innate immune responses and worsens brain injury outcomes. Autophagy 19:2026–2044. https://doi.org/10.1080/15548627.2023.2167689
Hu C, Wang L, Chodosh LA, Keith B, Simon MC (2003) Differential roles of hypoxia-inducible factor 1α ( HIF-1α) and HIF-2α in hypoxic gene regulation 23:9361–9374. https://doi.org/10.1128/MCB.23.24.9361
Huang J, Gao L, Li B, Liu C, Hong S, Min J, Hong L (2019) Knockdown of hypoxia-inducible factor 1α (HIF-1α) promotes autophagy and inhibits phosphatidylinositol 3-kinase (PI3K)/AKT/ mammalian target of rapamycin (mTOR) signaling pathway in ovarian cancer cells. Med Sci Monit 25:4250–4263. https://doi.org/10.12659/MSM.915730
Ivacko JA, Sun R, Silverstein FS (1996) Hypoxic-ischemic brain injury induces an acute microglial reaction in perinatal rats. Pediatr Res 39:39–47. https://doi.org/10.1203/00006450-199601000-00006
Jiao M, Ren F, Zhou L, Zhang X, Zhang L, Wen T, Wei L, Wang X, Shi H, Bai L et al (2014) Peroxisome proliferator-activated receptor α activation attenuates the inflammatory response to protect the liver from acute failure by promoting the autophagy pathway. Cell Death Dis 5. https://doi.org/10.1038/cddis.2014.361
Korbecki J, Bajdak-Rusinek K (2019) The effect of palmitic acid on inflammatory response in macrophages: an overview of molecular mechanisms. Inflamm Res Off J Eur Histamine Res Soc 68:915–932. https://doi.org/10.1007/s00011-019-01273-5
Lauterbach MA, Hanke JE, Serefidou M, Mangan MSJ, Kolbe CC, Hess T, Rothe M, Kaiser R, Hoss F, Gehlen J et al (2019) Toll-like receptor signaling rewires macrophage metabolism and promotes histone acetylation via ATP-citrate lyase. Immunity 51:997-1011.e7. https://doi.org/10.1016/j.immuni.2019.11.009
Lawson LJ, Perry VH, Gordon S (1992) Turnover of resident microglia in the normal adult mouse brain. Neuroscience 48:405–415. https://doi.org/10.1016/0306-4522(92)90500-2
Lee JH, Phelan P, Shin M, Oh BC, Han X, Im SS, Osborne TF (2018) SREBP-1a–stimulated lipid synthesis is required for macrophage phagocytosis downstream of TLR4-directed mTORC1. Proc Natl Acad Sci U S A 115:E12228–E12234. https://doi.org/10.1073/pnas.1813458115
Li L, Zhang X, Yang D, Luo G, Chen S, Le W (2009) Hypoxia increases Aβ generation by altering β- and γ-cleavage of APP. Neurobiol Aging 30:1091–1098. https://doi.org/10.1016/j.neurobiolaging.2007.10.011
Li F, Wang L, Li JW, Gong M, He L, Feng R, Dai Z, Li SQ (2011) Hypoxia induced amoeboid microglial cell activation in postnatal rat brain is mediated by ATP receptor P2X4. BMC Neurosci 12. https://doi.org/10.1186/1471-2202-12-111
Lim Y, Kim S, Kim EK (2021) Palmitate reduces starvation-induced ER stress by inhibiting ER-phagy in hypothalamic cells. Mol Brain 14. https://doi.org/10.1186/s13041-021-00777-8
Loor G, Schumacker PT (2008) Role of Hypoxia-inducible factor in cell survival during myocardial ischemia-reperfusion. Cell Death Differ 15:686–690
Luo R, Su LY, Li G, Yang J, Liu Q, Yang LX, Zhang DF, Zhou H, Xu M, Fan Y et al (2020) Activation of PPARA-mediated autophagy reduces Alzheimer Disease-like pathology and cognitive decline in a murine model. Autophagy 16:52–69. https://doi.org/10.1080/15548627.2019.1596488
Melo HM, da Silva GSS, Sant’Ana MR, Teixeira CVL, Clarke JR, Miya Coreixas VS, de Melo BC, Fortuna JTS, Forny-Germano L, Ledo JH et al (2020) Palmitate is increased in the cerebrospinal fluid of humans with obesity and induces memory impairment in mice via pro-inflammatory TNF-α. Cell Rep 30:2180-2194.e8. https://doi.org/10.1016/j.celrep.2020.01.072
Mittelbronn M, Dietz K, Schluesener HJ, Meyermann R (2001) Local distribution of microglia in the normal adult human central nervous system differs by up to one order of magnitude. Acta Neuropathol 101:249–255. https://doi.org/10.1007/s004010000284
Nicholas SA, Sumbayev VV (2009) The involvement of hypoxia-inducible factor 1 alpha in toll-like receptor 7/8-mediated inflammatory response. Cell Res 19:973–983. https://doi.org/10.1038/cr.2009.44
Ock J, Cho H-J, Hong S, Kim I, Suk K (2005) Hypoxia as an initiator of neuroinflammation: microglial connections. Curr Neuropharmacol 3:183–191. https://doi.org/10.2174/1570159053586681
Oishi Y, Spann NJ, Link VM, Muse ED, Strid T, Edillor C, Kolar MJ, Matsuzaka T, Hayakawa S, Tao J et al (2017) SREBP1 contributes to resolution of pro-inflammatory TLR4 signaling by reprogramming fatty acid metabolism. Cell Metab 25:412–427. https://doi.org/10.1016/j.cmet.2016.11.009
Orihuela R, McPherson CA, Harry GJ (2016) Microglial M1/M2 polarization and metabolic states. Br J Pharmacol 173(4):649–665. https://doi.org/10.1111/bph.13139. Epub 2015 May 11. PMID: 25800044; PMCID: PMC4742299
Park HY, Kang HS, Im SS (2018) Recent insight into the correlation of SREBP-mediated lipid metabolism and innate immune response. J Mol Endocrinol 61:R123–R131
Pawlak M, Lefebvre P, Staels B (2015) Molecular mechanism of PPARα action and its impact on lipid metabolism, inflammation and fibrosis in non-alcoholic fatty liver disease. J Hepatol 62:720–733
Rigamonti E, Chinetti-Gbaguidi G, Staels B (2008) Regulation of macrophage functions by PPAR- Α, PPAR- Γ, and LXRs in Mice and Men. Arterioscler Thromb Vasc Biol 28:1050–1059
Sarkar K, Cai Z, Gupta R, Parajuli N, Fox-Talbot K, Darshan MS, Gonzalez FJ, Semenza GL (2012) Hypoxia-inducible factor 1 transcriptional activity in endothelial cells is required for acute phase cardioprotection induced by ischemic preconditioning. Proc Natl Acad Sci U S A 109:10504–10509. https://doi.org/10.1073/pnas.1208314109
Shen J, Xu S, Zhou H, Liu H, Jiang W, Hao J, Hu Z (2017) IL-1β Induces apoptosis and autophagy via mitochondria pathway in human degenerative nucleus pulposus cells. Sci Rep 7. https://doi.org/10.1038/srep41067
Sonar SA, Lal G (2019) The iNOS Activity during an immune response controls the CNS pathology in experimental autoimmune encephalomyelitis. Front Immunol 10. https://doi.org/10.3389/fimmu.2019.00710
Takeda H, Yamaguchi T, Yano H, Tanaka J (2021) Microglial metabolic disturbances and neuroinflammation in cerebral infarction. J Pharmacol Sci 145:130–139
Thameem Dheen S, Kaur C, Ling E-A (2007) Microglial activation and its implications in the brain diseases. Curr Med Chem 14:1189–1197. https://doi.org/10.2174/092986707780597961
Todisco S, Santarsiero A, Convertini P, De Stefano G, Gilio M, Iacobazzi V, Infantino V (2022) PPAR alpha as a metabolic modulator of the liver: role in the pathogenesis of nonalcoholic steatohepatitis (NASH). Biology (Basel) 11(5):792. https://doi.org/10.3390/biology11050792. PMID: 35625520; PMCID: PMC9138523
Tripathi VK, Subramaniyan SA, Hwang I (2019) Molecular and cellular response of co-cultured cells toward cobalt chloride (CoCl2)-induced hypoxia. ACS Omega 4:20882–20893. https://doi.org/10.1021/acsomega.9b01474
Urso CJ, Zhou H (2021) Palmitic acid lipotoxicity in microglia cells is ameliorated by unsaturated fatty acids. Int J Mol Sci 22. https://doi.org/10.3390/ijms22169093
Wang Z, Yang D, Zhang X, Li T, Li J, Tang Y, Le W (2011) Hypoxia-induced down-regulation of neprilysin by histone modification in mouse primary cortical and hippocampal neurons. PLoS One 6. https://doi.org/10.1371/journal.pone.0019229
Weidemann A, Johnson RS (2008) Biology of HIF-1alpha. Cell Death Differ 15:621–627
Xu S, Yu C, Ma X, Li Y, Shen Y, Chen Y, Huang S, Zhang T, Deng W, Wang Y (2021) IL-6 Promotes nuclear translocation of HIF-1α to aggravate chemoresistance of ovarian cancer cells. Eur J Pharmacol 894. https://doi.org/10.1016/j.ejphar.2020.173817
Yagishita S, Suzuki S, Yoshikawa K, Iida K, Hirata A, Suzuki M, Takashima A, Maruyama K, Hirasawa A, Awaji T (2017) Treatment of intermittent hypoxia increases phosphorylated tau in the hippocampus via biological processes common to aging. Mol Brain 10:1–14. https://doi.org/10.1186/s13041-016-0282-7
Yamamoto S, Masuda T (2023) Lipid in microglial biology—from material to mediator. Inflamm Regen 43(1):38
Yang Z, Zhao TZ, Zou YJ, Zhang JH, Feng H (2014) Hypoxia induces autophagic cell death through hypoxia-inducible factor 1α in microglia. PloS one 9(5):e96509
Yu T, Zhang X, Shi H, Tian J, Sun L, Hu X, Cui W (2019) P2Y12 Regulates microglia activation and excitatory synaptic transmission in spinal lamina II neurons during neuropathic pain in rodents. Cell Death Dis. https://doi.org/10.1038/s41419-019-1425-4
Zaarour RF, Azakir B, Hajam EY, Nawafleh H, Zeinelabdin NA, Engelsen AST, Thiery J, Jamora C, Chouaib S (2021) Role of hypoxia-mediated autophagy in tumor cell death and survival. Cancers (basel) 13:1–20
Zhang Y, Liu D, Hu H, Zhang P, Xie R, Cui W (2019) HIF-1α/BNIP3 signaling pathway-induced autophagy plays protective role during myocardial ischemia-reperfusion injury. Biomed Pharmacother 120:109464
Zhang JZ, Ward KW (2010) WY-14 643, a selective PPARα agonist, induces proinflammatory and proangiogenic responses in human ocular cells. Int J Toxicol 29:496–504. https://doi.org/10.1177/1091581810376674
Zhou H, Chang SL (2023) Meta-analysis of the effects of palmitic acid on microglia activation and neurodegeneration. NeuroImmune Pharmacol Ther 2(3):281–291
Zhu H, Wang D, Liu Y, Su Z, Zhang L, Chen F, Shao G (2013) Role of the Hypoxia-inducible factor-1 alpha induced autophagy in the conversion of non-stem pancreatic cancer cells into CD133+ pancreatic cancer stem-like cells. Cancer Cell Int 13(1):1–8
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Florance, I., Ramasubbu, S. Regulation of genes involved in the metabolic adaptation of murine microglial cells in response to elevated HIF-1α mediated activation. Immunogenetics 76, 93–108 (2024). https://doi.org/10.1007/s00251-024-01334-y
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DOI: https://doi.org/10.1007/s00251-024-01334-y