Hypoxia-Inducible Transcription Factors in Signaling during Myocardial Ischemia: History
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Despite increasing availability and more successful interventional approaches to restore coronary reperfusion, myocardial ischemia-reperfusion injury is a substantial cause of morbidity and mortality worldwide. During myocardial ischemia, the myocardium becomes profoundly hypoxic, thus causing stabilization of hypoxia-inducible transcription factors (HIF). Stabilization of HIF leads to a transcriptional program that promotes adaptation to hypoxia and cellular survival. Transcriptional consequences of HIF stabilization include increases in extracellular production and signaling effects of adenosine. Extracellular adenosine functions as a signaling molecule via the activation of adenosine receptors. Several studies implicated adenosine signaling in cardioprotection, particularly through the activation of the Adora2a and Adora2b receptors. Adenosine receptor activation can lead to metabolic adaptation to enhance ischemia tolerance or dampen myocardial reperfusion injury via signaling events on immune cells. Many studies highlight that clinical strategies to target the hypoxia-adenosine link could be considered for clinical trials. This could be achieved by using pharmacologic HIF activators or by directly enhancing extracellular adenosine production or signaling as a therapy for patients with acute myocardial infarction, or undergoing cardiac surgery. 

  • adenosine
  • hypoxia
  • CD73
  • CD39
  • Adora2a
  • A2A
  • A2B
  • Adora2b
  • ENT1
  • ENT2

1. Hypoxia-Inducible Transcription Factors (HIF) Are Stabilized during Myocardial Ischemia and Provide Cardioprotection

During myocardial ischemia, the cardiac tissues become profoundly hypoxic. This is caused by an attenuated supply of oxygen and metabolites to the area at risk by the occluded coronary artery. Several previous studies have shown that even very short episodes of myocardial ischemia (as short as only 5 min) are associated with the stabilization of HIF [1]. These transcription factors were discovered in the early 1990s in studies of the erythropoietin promoter [2][3][4], a discovery that was subsequently awarded the Nobel Prize in 2019 [5]. HIF are heterodimeric transcription factors with a constitutively expressed beta unit (HIF1B) [6]. In contrast, the alpha unit (HIF1A or HIF2A) is substantially regulated on the post-translational level [7][8][9][10]. During normal oxygen availability, HIF1A/HIF2A are targeted for proteasomal degradation through a molecular pathway that involves oxygen-sensing HIF prolyl hydroxylases (PHD1, PHD2, or PHD3) [11][12][13][14]. PHDs use oxygen as a co-factor to promote hydroxylation of a conserved prolyl-residue with the HIF1A/HIF2A subunit, which subsequently promotes binding of the Von-Hippel-Lindau gene product, polyubiquitination, and proteasomal degradation [9][15][16][17]. However, if oxygen levels fall, PHDs are functionally inactivated. In addition, other metabolic changes in the microenvironment [10][18][19], or oxygen-independent mechanisms of PHD inhibition, have been demonstrated previously (e.g., elevations of succinate levels) [20][21]. These changes in metabolic supply and demand lead to the stabilization of HIF1A or HIF2A, which form a transcriptionally active complex with the HIF1B subunit [22]. This transcriptionally active complex can bind to hypoxia-response elements (HREs) within the promoter region of hypoxia-responsive genes, and promote changes in the transcription rate of the specific gene products. Famous HIF target genes include, for example, erythropoietin or vascular endothelial growth factor. However, studies in genetic models show that approximately 570 genes are transcriptionally altered by the activity of HIF, and most likely more than that [23]. In many instances, HIF binding to HREs will cause transcriptional increases for specific gene products [24][25], but, very frequently, this can also cause repression of a specific gene product [23][26][27][28]. Repression of a specific gene product by HIF is often related to the induction of HIF-dependent microRNAs (miRNAs), which promote the subsequent repression of an indirect HIF target gene [29][30]. For example, a recent study demonstrated that HIF-dependent induction of miRNA miR122 causes repression of PHD1 as an indirect HIF1A-target gene [30].
Many studies on the consequences of HIF stabilization during acute myocardial ischemia-reperfusion injury highlight the protective functions of HIF. These studies include evidence that both HIF1A or HIF2A stabilization can have cardioprotective functions, but most likely involve different tissue-compartments and different hypoxia-dependent target genes [31][32][33][34][35]. Similarly, pharmacologic studies using small-molecular inhibitors of PHDs (PHD inhibitors) demonstrate that pre-treatment approaches are associated with attenuated myocardial ischemia-reperfusion injury [1]. Importantly, orally available HIF activators have recently been used in phase 3 clinical trials for the treatment of renal anemia. These studies showed that HIF activator treatment is at least equally potent to promote hemoglobin levels through the induction of erythropoietin as compared to treatment with recombinant erythropoietin [36][37][38][39]. These pharmacologic HIF activators have rarely been explored in clinical trials for cardioprotection. However, there is strong experimental evidence that those compounds (e.g., vadadustat or roxadustat) could potentially be used to attenuate myocardial ischemia-reperfusion injury in patients with acute myocardial infarction (MI) or for cardioprotection during cardiac surgery [9].

2. Role of HIF in Regulating Adenosine Signaling during Myocardial Ischemia-Reperfusion Injury

Several previous studies have proposed linkages between hypoxia, HIF, and extracellular adenosine signaling as a means to providing tissue-adaptation, or to dampen hypoxia-driven inflammation [40][41][42]. In the extracellular compartment, adenosine is generated from precursor nucleotides, such as ATP or ADP [43][44][45][46]. Once adenosine is generated, it can signal through four distinct adenosine receptors, including the adenosine A1 receptor (ADORA1), the adenosine A2A receptor (ADORA2A), the adenosine A2B receptor (ADORA2B), and the adenosine A3 receptor (ADORA3) [47][48]. These G-protein coupled receptors have all been implicated in cardio-adaptive responses [32]. For example, the Adora1 is known to mediate the heart-rate slowing effects of intravenous adenosine, used for the treatment of supraventricular tachycardia [49]. In particular, the Adora2a and the Adora2b have been shown to dampen inflammatory responses [50][51][52][53]. For example, Adora2a signaling has been discovered on polymorphonuclear neutrophils (PMNs) [54] and contributes to attenuated inflammatory responses [55][56]. The subsequent uptake of adenosine from the extracellular compartment [28][57], and metabolism to inosine [58][59][60][61] or AMP is implicated in terminating extracellular adenosine signaling.

2.1. Impact of Hypoxia-Signaling on the Production of Extracellular Adenosine

During conditions of hypoxia, inflammation, or cellular stress, different cells release nucleotides, particularly in the form of ATP or ADP. For example, ATP can be released from inflammatory cells through specific molecular pathways [62][63][64][65][66][67][68]. The extracellular release of ADP has been described extensively from platelets [47]. ATP or ADP can function as precursor molecules for the extracellular production of adenosine. This process is a two-step, enzymatically controlled pathway. As the first step, the ectonucleotidase CD39 converts extracellular ATP or ADP to AMP [69]. Studies in gene-targeted mice for cd39 (cd39−/− mice) [70] show that these mice experience larger myocardial infarct sizes in the context of diminished levels of AMP and adenosine [71]. Moreover, cd39−/− mice are not protected by ischemic preconditioning, where one or more preceding cycles of myocardial ischemia are associated with the attenuated size of injury [71][72][73]. Importantly, several studies demonstrate that the transcript and protein levels, and also the enzymatic function of CD39 are increased during ischemia, inflammation, or hypoxia [71][74][75][76][77][78]. Studies on the transcriptional mechanism controlling CD39 expression during limited oxygen availability link the increased CD39 levels to transcriptional control of Sp1 [79][80].
The second step for the extracellular production of adenosine is under the control of the ecto-5′-nucleotidase CD73 [81]. This enzyme promotes the extracellular conversion of AMP to adenosine and can be considered as a “pace-maker” for extracellular adenosine generation. Similar to cd39−/− mice, gene-targeted mice for cd73 [82] experience increased myocardial injury and are not protected by ischemic preconditioning [83]. As would be expected based on its enzymatic function, cd73−/− mice experience attenuated concentrations of cardiac adenosine in conjunction with elevated cardiac AMP concentrations during myocardial injury [83]. Moreover, transcript, protein, and functional levels of CD73 are increased under hypoxia [83]. Several studies link these increases to a transcriptional program under the control of HIF1A. Studies with transcription factor binding assays and promoter constructs had demonstrated that CD73 is a classic HIF target gene and implicate HIF-dependent induction of CD73 in hypoxia-adaptive responses [75][76][82]. When exposed to myocardial ischemia-reperfusion, cd73−/− mice experience larger infarct sizes and higher elevations of cardiac injury markers (troponin I) compared to control animals [83]. Subsequent studies during myocardial injury demonstrate that the protective effects of pharmacologic HIF activator treatment is attenuated in cd73−/− mice [1], thereby directly implicating HIF-dependent CD73 regulation in cardioprotection. Together, these studies indicate that during myocardial ischemia, hypoxia signaling through Sp1 and HIF1A coordinate the transcriptional induction of CD39 and CD73, which leads to the increased production of extracellular adenosine and thereby contributes to attenuated myocardial infarct sizes (Figure 1).
Figure 1. Hypoxia increases extracellular adenosine during myocardial ischemia. In the context of hypoxia, different cell types such as inflammatory cells and platelets release large amounts of adenine nucleotides (particularly ATP or ADP). The ectonucleotidases CD39 and CD73 convert ADP/ATP to AMP and AMP to adenosine, respectively. Therefore, the level of extracellular adenosine during hypoxia or inflammation critically depends on the expression level and enzymatic activity of CD39 and CD73. Hypoxia promotes the induction of CD39 expression through SP1 signaling, and of CD73 expression through binding of the transcription factor hypoxia-inducible factor HIF1A to a hypoxia-response element (HRE) within the CD73 promoter. ATP: adenosine triphosphate; ADP: adenosine diphosphate; AMP: adenosine monophosphate.

2.2. Role of HIF in Coordinating Extracellular Adenosine Signaling during Myocardial Ischemia-Reperfusion Injury

As described above, myocardial ischemia-reperfusion injury is associated with increased production of extracellular adenosine. Adenosine acts on four different receptor subtypes, including Adora1, Adora2a, Adora2b, and Adora3. All these receptors have been implicated in providing cardioprotection [83][84][85][86]. However, only the Adora2a and the Adora2b are transcriptionally regulated by HIF. They are highly expressed on a variety of different cellular sources, for example on cells of the innate immune system [78][87][88], erythrocytes [89][90], cardiac myocytes [35], stromal or epithelial cells [91][92][93][94], regulatory T-cells [95][96][97], and other immune cells [98]. Several previous studies have shown that the Adora2b promoter contains an HRE and can be directly induced by HIF1A during conditions of hypoxia [99], inflammation [92][100], or during myocardial ischemia-reperfusion injury [1][35]. Similarly, the Adora2a has been previously identified as a target for hypoxia-signaling through the HIF2A isoform [101]. Studies in murine models of myocardial ischemia-reperfusion injury implicate both Adora2a and Adora2b in cardioprotection from ischemia-reperfusion. For example, murine studies demonstrate that infarct size-reducing effects of treatment with an Adora2a agonist are linked to Adora2a signaling on bone-marrow-derived T or B lymphocytes [102], which were subsequently identified to be most likely CD4+ T cells [103]. Similar to the Adora2a, several studies implicate the Adora2b in cardioprotection from ischemia-reperfusion injury. For example, Adora2b−/− mice are not protected by ischemic preconditioning and exhibit larger myocardial infarct sizes [83]. Moreover, treatment with a specific agonist for the Adora2b is associated with a significant reduction in infarct sizes in murine [83] or rat [104] models of myocardial ischemia-reperfusion injury. Studies using treatment approaches with the pharmacologic HIF activator dimethyloxalylglycine (DMOG) demonstrate abolished cardioprotection by this treatment in Adora2b−/− mice, thereby directly linking HIF1A and Adora2b signaling during cardioprotection [1]. Studies on the cellular source of the Adora2b receptor implicate myeloid-dependent Adora2b signaling in cardioprotection from ischemia-reperfusion injury [105][106]. Other studies suggest that Adora2b signaling on cardiac myocytes or inflammatory cells can interface with the stabilization of circadian rhythm signaling molecules, thereby contributing to the circadian oscillation of myocardial injury [32][35][107][108][109]. In addition, a recent study demonstrated a regulatory function for Adora2b signaling in promoting epicardial stromal cells′ HIF stabilization after myocardial infarction as an additional crosstalk between Adora2b and HIF implicated in cardioprotection after myocardial infarction [93]. Taken together, these findings demonstrate HIF-dependent control of adenosine receptor expression and signaling in attenuating myocardial injury during ischemia-reperfusion (Figure 2).
Figure 2. HIF protects against myocardial ischemia-reperfusion injury through the modulation of adenosine receptor signaling events. Adenosine receptors belong to the G protein-coupled receptor family and are composed of different subunits: the Gs alpha subunits (Gαs) and the beta-gamma subunit complex (Gβ/γ). The adenosine receptors Adora2a and Adora2b have been identified as target genes of HIF. Under hypoxic conditions, Adora2a and Adora2b are transcriptionally induced by HIF2A and HIF1A, respectively. Activation of these receptors with their specific agonists showed reduced infarct size in murine models of myocardial ischemia-reperfusion injury, suggesting their role in mediating the cardioprotective effects of HIF. The cardioprotection provided is associated with the activation of Adora2a signaling on lymphocytes and Adora2b signaling on myeloid cells and cardiomyocytes. The red arrowhead denotes upregulation. A2A: Adenosine A2a Receptor. A2B: Adenosine A2b Receptor.

2.3. HIF-Dependent Promotion of Alternative Adenosine Receptor Activation

Several studies implicate the neuronal guidance molecule netrin-1 [110] in alternative mechanisms of adenosine receptor activation, particularly for the Adora2b [111][112]. Netrin-1 was discovered as a neuronal guidance molecule. Its function was originally described as netrin-1 secreted from cells of the floor plate of the mammalian embryonic neural tube [113][114][115]. Its secretion sets up a circumferential gradient of netrin-1, which in some instances attracts or in other instances repels other axons to the ventral midline [110]. Receptors for secreted netrin-1 include, for example, the receptor DCC (deleted in colorectal cancer) [116] and the UNC5 homologs (UNC5A, B, C, and D) [117] and neogenin-1 [118]. Importantly, the profound ability of the netrin-1 in guiding the repulse or outgrowth of neuronal cells makes it an ideal candidate molecule for the coordination of inflammatory cell migration [119].
Studies utilizing a two-hybrid screen of a human brain cDNA library discovered a previously unreported interaction of netrin-1 with the Adora2b adenosine receptor [120]. Several studies using genetic and pharmacologic approaches demonstrate that netrin-1 can function to promote Adora2b signaling during inflammatory conditions outside of the brain, including acute lung injury [25][112][121][122], inflammatory peritonitis [111], intestinal inflammation [123][124], inflammatory kidney disease [125], corneal wound healing [126], and also myocardial ischemia-reperfusion injury [127]. However, one study found inconsistent results by showing that the Adora2b is actually not expressed in neurons, and is functionally not required for commissural axon guidance in the context of netrin-1 signaling [128]. At present, it is not well understood how netrin-1 and the Adora2b interact, including the possibility that netrin-1 could directly bind to Adora2b as its ligand, a role of netrin-1-dependent enhancement of extracellular adenosine levels, or indirect effects of netrin-1 by binding to a classic netrin-1 receptor and enhancing intracellular signaling cascades under the control of the Adora2b. A recent study found that netrin-1 levels were up-regulated in samples of patients who experienced myocardial ischemia-reperfusion injury [127]. Subsequent studies in mice with deletion of netrin-1 in the myeloid lineage (Ntn1loxp/loxp LyzM Cre+ mice) revealed selectively larger infarct sizes and higher troponin levels, while other mouse lines with conditional deletion of netrin-1 in other tissues didn’t experience a similar phenotype. Importantly, treatment studies with recombinant netrin-1 demonstrated that the interaction of netrin-1 with myeloid-dependent Adora2b signaling is critical in this pathway, suggesting an autocrine signaling pathway [127]. Previous studies have found that the promoter of netrin-1 contains an HRE and that HIF1A binding to the netrin-1 promoter dramatically increases netrin-1 expression of transcript and protein levels [129]. Subsequent studies in myeloid cells confirmed that finding [130], including recent studies showing that Hif1a-deficient myeloid cells fail to induce netrin during injury [25]. In conjunction with these studies, it is conceivable that hypoxia-signaling coordinates netrin-1 and Adora2b signaling in an autocrine loop where neutrophil-derived netrin-1 attenuates myocardial injury through signaling events on Adora2b receptors expressed on myeloid cells of the innate immune system (Figure 3).
Figure 3. HIF coordinates alternative adenosine receptor signaling via increasing netrin-1 expression and signaling through Adora2b. During myocardial reperfusion injury, different types of inflammatory cells, such as neutrophils, monocytes, etc. infiltrate into the myocardial tissue. This further exacerbates tissue hypoxia and tissue damage. During reperfusion, the transcript and protein levels of Netrin-1 are robustly increased in patients with myocardial ischemia and in mice with myocardial IR injury. The increased expression of netrin-1 is mediated by HIF1A activity, which can bind to an HRE within the Netrin-1 promoter. The increased release of netrin-1 enhances Adora2b signaling by interacting with myeloid Adora2b in an autocrine manner, dampens the accumulation of inflammatory cells, and ultimately mediates cardioprotection against IR injury. The red arrowhead denotes increase, and the dark blue arrowhead denotes decrease. A2B: Adenosine A2b Receptor. NTN1: Netrin-1.

2.4. Impact of HIF Signaling on Extracellular Adenosine Uptake and Metabolism

Previous studies have implicated HIF in modulating extracellular adenosine uptake and metabolism. In this context, the consequences of HIF transcriptional activity function towards attenuating extracellular adenosine uptake and intracellular metabolism, thereby enhancing extracellular adenosine signaling events. Adenosine signaling is terminated through equilibrative nucleoside transporters (ENTs), particularly ENT1 and ENT2 [26][57][131]. Those are channels that allow the bidirectional flow of adenosine across the cell membrane following its gradient. Extracellular production of adenosine is dramatically increased and the gradient for adenosine is directed from the extracellular compartment towards the intracellular side during ischemia-reperfusion injury. Therefore, deletion or inhibition of adenosine transporters with an ENT inhibitor such as dipyridamole will result in increased extracellular adenosine levels. Due to its function as an ENT inhibitor, dipyridamole treatment has been used clinically for many decades during pharmacologic stress echocardiography, where it increases coronary adenosine levels, and can unmask coronary artery stenosis [132][133]. Importantly, for the hypoxia-adenosine link during myocardial injury, previous studies have shown that HIF functions to repress both ENT1 and ENT2 during conditions of hypoxia or inflammation, and thereby functions to increase extracellular adenosine levels [26][90][92][134][135][136]. Interestingly, mice with global deletion of Ent1 experience elevated plasma levels of adenosine, which can contribute to cardioprotection [137]. However, the individual contributions of ENT1 versus ENT2 during myocardial ischemia-reperfusion injury have not been addressed, for example by using genetic murine models. Nevertheless, global inhibition of ENTs with dipyridamole has been implicated in cardioprotection from ischemia-reperfusion injury [138][139]. Taken together, these studies highlight the likelihood that HIF-dependent repression of ENTs contributes to cardioprotection from ischemia-reperfusion injury. However, it would be important to define the individual contributions of ENT1 versus ENT2, as well as their tissue-specific functions and adenosine receptor signaling events in experimental studies of myocardial ischemia-reperfusion injury (Figure 4).
Figure 4. HIF contributes to attenuated adenosine uptake, reduced adenosine metabolism and concomitant cardioprotection during myocardial ischemia-reperfusion injury. Equilibrative nucleoside transporters (ENTs) regulate the uptake of adenosine from the extracellular towards the intracellular compartment where the major routes of adenosine removal is based on phosphorylation to AMP via adenosine kinase, thereby modulating adenosine levels. During myocardial ischemia-reperfusion injury, HIF transcriptionally represses ENT1, ENT2 and adenosine kinase, leading to elevated extracellular adenosine levels. The inhibition of ENTs in mice with dipyridamole or global deletion of Ent1 showed decreased intracellular adenosine uptake and increased extracellular adenosine levels, ultimately exerting cardioprotective effects. These indicate the contribution of HIF-dependent repression of ENTs to adenosine-mediated cardioprotection. ENT: equilibrative nucleoside transporter; AK: adenosine kinase.
In addition to the repression of ENT1 and ENT2, HIF1A has also been shown to repress a key metabolic process in intracellular adenosine metabolism. Adenosine can be metabolized intracellularly to AMP by the adenosine kinase (AK). Studies on hypoxia responses of AK demonstrate that hypoxia is associated with attenuated transcript and protein levels of AK. Moreover, studies in genetic models directly implicate HIF1A in its repression and demonstrate increased adenosine responses with AK repression [140]. Several studies implicate this pathway in cardioprotection. For example, experimental studies in rats treated with the AK inhibitor iodotubercidin demonstrate attenuated myocardial infarct sizes [141]. Together, these studies indicate the likelihood that HIF1A-dependent repression of AK contributes to adenosine-dependent cardio- protection from ischemia-reperfusion injury (Figure 4).

This entry is adapted from the peer-reviewed paper 10.3390/biomedicines10081939

References

  1. Eckle, T.; Kohler, D.; Lehmann, R.; El Kasmi, K.C.; Eltzschig, H.K. Hypoxia-Inducible Factor-1 Is Central to Cardioprotection: A New Paradigm for Ischemic Preconditioning. Circulation 2008, 118, 166–175.
  2. Wang, G.; Jiang, B.; Rue, E.; Semenza, G. Hypoxia-Inducible Factor 1 is a Basic-Helix-Loop-Helix-PAS Heterodimer Regulated by Cellular O2 Tension. Proc. Natl. Acad. Sci. USA 1995, 92, 5510–5514.
  3. Semenza, G.L.; Roth, P.H.; Fang, H.M.; Wang, G.L. Transcriptional regulation of genes encoding glycolytic enzymes by hypoxia-inducible factor 1. J. Biol. Chem. 1994, 269, 23757–23763.
  4. Wang, G.L.; Semenza, G.L. Characterization of hypoxia-inducible factor 1 and regulation of DNA binding activity by hypoxia. J. Biol. Chem. 1993, 268, 21513–21518.
  5. Colgan, S.P.; Furuta, G.T.; Taylor, C.T. Hypoxia and Innate Immunity: Keeping Up with the HIFsters. Annu. Rev. Immunol. 2020, 38, 341–363.
  6. Eltzschig, H.K.; Carmeliet, P. Hypoxia and inflammation. N. Engl. J. Med. 2011, 364, 656–665.
  7. Li, X.; Berg, N.K.; Mills, T.; Zhang, K.; Eltzschig, H.K.; Yuan, X. Adenosine at the Interphase of Hypoxia and Inflammation in Lung Injury. Front. Immunol. 2020, 11, 604944.
  8. Lee, J.W.; Ko, J.; Ju, C.; Eltzschig, H.K. Hypoxia signaling in human diseases and therapeutic targets. Exp. Mol. Med. 2019, 51, 1–13.
  9. Yuan, X.; Lee, J.W.; Bowser, J.L.; Neudecker, V.; Sridhar, S.; Eltzschig, H.K. Targeting Hypoxia Signaling for Perioperative Organ Injury. Anesth. Analg. 2018, 126, 308–321.
  10. Taylor, C.T.; Colgan, S.P. Regulation of immunity and inflammation by hypoxia in immunological niches. Nat. Rev. Immunol. 2017, 17, 774–785.
  11. Fraisl, P.; Aragones, J.; Carmeliet, P. Inhibition of oxygen sensors as a therapeutic strategy for ischaemic and inflammatory disease. Nat. Rev. Drug Discov. 2009, 8, 139–152.
  12. Brown, E.; Rowan, C.; Strowitzki, M.J.; Fagundes, R.R.; Faber, K.N.; Guntsch, A.; Halligan, D.N.; Kugler, J.; Jones, F.; Lee, C.T.; et al. Mucosal inflammation downregulates PHD1 expression promoting a barrier-protective HIF-1alpha response in ulcerative colitis patients. FASEB J. 2020, 34, 3732–3742.
  13. Kennel, K.B.; Burmeister, J.; Schneider, M.; Taylor, C.T. The PHD1 oxygen sensor in health and disease. J. Physiol. 2018, 596, 3899–3913.
  14. Tambuwala, M.M.; Cummins, E.P.; Lenihan, C.R.; Kiss, J.; Stauch, M.; Scholz, C.C.; Fraisl, P.; Lasitschka, F.; Mollenhauer, M.; Saunders, S.P.; et al. Loss of prolyl hydroxylase-1 protects against colitis through reduced epithelial cell apoptosis and increased barrier function. Gastroenterology 2010, 139, 2093–2101.
  15. Bowser, J.L.; Phan, L.H.; Eltzschig, H.K. The Hypoxia-Adenosine Link during Intestinal Inflammation. J. Immunol. 2018, 200, 897–907.
  16. Koeppen, M.; Eckle, T.; Eltzschig, H.K. Interplay of hypoxia and A2B adenosine receptors in tissue protection. Adv. Pharmacol. 2011, 61, 145–186.
  17. Semenza, G.L. Targeting HIF-1 for cancer therapy. Nat. Rev. Cancer 2003, 3, 721–732.
  18. Kelly, C.J.; Zheng, L.; Campbell, E.L.; Saeedi, B.; Scholz, C.C.; Bayless, A.J.; Wilson, K.E.; Glover, L.E.; Kominsky, D.J.; Magnuson, A.; et al. Crosstalk between Microbiota-Derived Short-Chain Fatty Acids and Intestinal Epithelial HIF Augments Tissue Barrier Function. Cell Host Microbe 2015, 17, 662–671.
  19. Cartwright, I.M.; Dowdell, A.S.; Lanis, J.M.; Brink, K.R.; Mu, A.; Kostelecky, R.E.; Schaefer, R.E.M.; Welch, N.; Onyiah, J.C.; Hall, C.H.T.; et al. Mucosal acidosis elicits a unique molecular signature in epithelia and intestinal tissue mediated by GPR31-induced CREB phosphorylation. Proc. Natl. Acad. Sci. USA 2021, 118, e2023871118.
  20. Vohwinkel, C.U.; Coit, E.J.; Burns, N.; Elajaili, H.; Hernandez-Saavedra, D.; Yuan, X.; Eckle, T.; Nozik, E.; Tuder, R.M.; Eltzschig, H.K. Targeting alveolar-specific succinate dehydrogenase A attenuates pulmonary inflammation during acute lung injury. FASEB J. 2021, 35, e21468.
  21. Eckle, T.; Brodsky, K.; Bonney, M.; Packard, T.; Han, J.; Borchers, C.H.; Mariani, T.J.; Kominsky, D.J.; Mittelbronn, M.; Eltzschig, H.K. HIF1A reduces acute lung injury by optimizing carbohydrate metabolism in the alveolar epithelium. PLoS Biol. 2013, 11, e1001665.
  22. Eltzschig, H.K.; Bratton, D.L.; Colgan, S.P. Targeting hypoxia signalling for the treatment of ischaemic and inflammatory diseases. Nat. Rev. Drug Discov. 2014, 13, 852–869.
  23. Manalo, D.J.; Rowan, A.; Lavoie, T.; Natarajan, L.; Kelly, B.D.; Ye, S.Q.; Garcia, J.G.N.; Semenza, G.L. Transcriptional regulation of vascular endothelial cell responses to hypoxia by HIF-1. Blood 2005, 105, 659–669.
  24. Bowser, J.L.; Lee, J.W.; Yuan, X.; Eltzschig, H.K. The Hypoxia-Adenosine Link during Inflammation. J. Appl. Physiol. 2017, 123, 1303–1320.
  25. Berg, N.K.; Li, J.; Kim, B.; Mills, T.; Pei, G.; Zhao, Z.; Li, X.; Zhang, X.; Ruan, W.; Eltzschig, H.K.; et al. Hypoxia-inducible factor-dependent induction of myeloid-derived netrin-1 attenuates natural killer cell infiltration during endotoxin-induced lung injury. FASEB J. 2021, 35, e21334.
  26. Eltzschig, H.K.; Abdulla, P.; Hoffman, E.; Hamilton, K.E.; Daniels, D.; Schonfeld, C.; Loffler, M.; Reyes, G.; Duszenko, M.; Karhausen, J.; et al. HIF-1-dependent repression of equilibrative nucleoside transporter (ENT) in hypoxia. J. Exp. Med. 2005, 202, 1493–1505.
  27. Zheng, W.; Kuhlicke, J.; Jackel, K.; Eltzschig, H.K.; Singh, A.; Sjoblom, M.; Riederer, B.; Weinhold, C.; Seidler, U.; Colgan, S.P.; et al. Hypoxia inducible factor-1 (HIF-1)-mediated repression of cystic fibrosis transmembrane conductance regulator (CFTR) in the intestinal epithelium. FASEB J. 2009, 23, 204–213.
  28. Morote-Garcia, J.C.; Rosenberger, P.; Nivillac, N.M.; Coe, I.R.; Eltzschig, H.K. Hypoxia-inducible factor-dependent repression of equilibrative nucleoside transporter 2 attenuates mucosal inflammation during intestinal hypoxia. Gastroenterology 2009, 136, 607–618.
  29. Bruning, U.; Cerone, L.; Neufeld, Z.; Fitzpatrick, S.F.; Cheong, A.; Scholz, C.C.; Simpson, D.A.; Leonard, M.O.; Tambuwala, M.M.; Cummins, E.P.; et al. MicroRNA-155 promotes resolution of hypoxia-inducible factor 1alpha activity during prolonged hypoxia. Mol. Cell. Biol. 2011, 31, 4087–4096.
  30. Ju, C.; Wang, M.; Tak, E.; Kim, B.; Emontzpohl, C.; Yang, Y.; Yuan, X.; Kutay, H.; Liang, Y.; Hall, D.R.; et al. Hypoxia-inducible factor-1alpha-dependent induction of miR122 enhances hepatic ischemia tolerance. J. Clin. Investig. 2021, 131, e140300.
  31. Koeppen, M.; Lee, J.W.; Seo, S.W.; Brodsky, K.S.; Kreth, S.; Yang, I.V.; Buttrick, P.M.; Eckle, T.; Eltzschig, H.K. Hypoxia-inducible factor 2-alpha-dependent induction of amphiregulin dampens myocardial ischemia-reperfusion injury. Nat. Commun. 2018, 9, 816.
  32. Eltzschig, H.K.; Bonney, S.K.; Eckle, T. Attenuating myocardial ischemia by targeting A2B adenosine receptors. Trends Mol. Med. 2013, 19, 345–354.
  33. Lee, J.W.; Koeppen, M.; Seo, S.W.; Bowser, J.L.; Yuan, X.; Li, J.; Sibilia, M.; Ambardekar, A.V.; Zhang, X.; Eckle, T.; et al. Transcription-independent Induction of ERBB1 through Hypoxia-inducible Factor 2A Provides Cardioprotection during Ischemia and Reperfusion. Anesthesiology 2020, 132, 763–780.
  34. Gao, R.Y.; Wang, M.; Liu, Q.; Feng, D.; Wen, Y.; Xia, Y.; Colgan, S.P.; Eltzschig, H.K.; Ju, C. Hypoxia-Inducible Factor-2alpha Reprograms Liver Macrophages to Protect Against Acute Liver Injury Through the Production of Interleukin-6. Hepatology 2020, 71, 2105–2117.
  35. Eckle, T.; Hartmann, K.; Bonney, S.; Reithel, S.; Mittelbronn, M.; Walker, L.A.; Lowes, B.D.; Han, J.; Borchers, C.H.; Buttrick, P.M.; et al. Adora2b-elicited Per2 stabilization promotes a HIF-dependent metabolic switch crucial for myocardial adaptation to ischemia. Nat. Med. 2012, 18, 774–782.
  36. Chertow, G.M.; Pergola, P.E.; Farag, Y.M.K.; Agarwal, R.; Arnold, S.; Bako, G.; Block, G.A.; Burke, S.; Castillo, F.P.; Jardine, A.G.; et al. Vadadustat in Patients with Anemia and Non-Dialysis-Dependent CKD. N. Engl. J. Med. 2021, 384, 1589–1600.
  37. Kaplan, J. Roxadustat and Anemia of Chronic Kidney Disease. N. Engl. J. Med. 2019, 381, 1070–1072.
  38. Chen, N.; Hao, C.; Peng, X.; Lin, H.; Yin, A.; Hao, L.; Tao, Y.; Liang, X.; Liu, Z.; Xing, C.; et al. Roxadustat for Anemia in Patients with Kidney Disease Not Receiving Dialysis. N. Engl. J. Med. 2019, 381, 1001–1010.
  39. Chen, N.; Hao, C.; Liu, B.C.; Lin, H.; Wang, C.; Xing, C.; Liang, X.; Jiang, G.; Liu, Z.; Li, X.; et al. Roxadustat Treatment for Anemia in Patients Undergoing Long-Term Dialysis. N. Engl. J. Med. 2019, 381, 1011–1022.
  40. Kiers, D.; Wielockx, B.; Peters, E.; van Eijk, L.T.; Gerretsen, J.; John, A.; Janssen, E.; Groeneveld, R.; Peters, M.; Damen, L.; et al. Short-Term Hypoxia Dampens Inflammation in vivo via Enhanced Adenosine Release and Adenosine 2B Receptor Stimulation. EBioMedicine 2018, 33, 144–156.
  41. Kiers, H.D.; Scheffer, G.J.; van der Hoeven, J.G.; Eltzschig, H.K.; Pickkers, P.; Kox, M. Immunologic Consequences of Hypoxia during Critical Illness. Anesthesiology 2016, 125, 237–249.
  42. Hasko, G.; Antonioli, L.; Cronstein, B.N. Adenosine metabolism, immunity and joint health. Biochem. Pharmacol. 2018, 151, 307–313.
  43. Ferrari, D.; McNamee, E.N.; Idzko, M.; Gambari, R.; Eltzschig, H.K. Purinergic Signaling During Immune Cell Trafficking. Trends Immunol. 2016, 37, 399–411.
  44. Ferrari, D.; Bianchi, N.; Eltzschig, H.K.; Gambari, R. MicroRNAs Modulate the Purinergic Signaling Network. Trends Mol. Med. 2016, 22, 905–918.
  45. Idzko, M.; Ferrari, D.; Riegel, A.K.; Eltzschig, H.K. Extracellular nucleotide and nucleoside signaling in vascular and blood disease. Blood 2014, 124, 1029–1037.
  46. Idzko, M.; Ferrari, D.; Eltzschig, H.K. Nucleotide signalling during inflammation. Nature 2014, 509, 310–317.
  47. Eltzschig, H.K.; Sitkovsky, M.V.; Robson, S.C. Purinergic signaling during inflammation. N. Engl. J. Med. 2012, 367, 2322–2333.
  48. Hasko, G.; Csoka, B.; Nemeth, Z.H.; Vizi, E.S.; Pacher, P. A(2B) adenosine receptors in immunity and inflammation. Trends Immunol. 2009, 30, 263–270.
  49. Koeppen, M.; Eckle, T.; Eltzschig, H.K. Selective deletion of the A1 adenosine receptor abolishes heart-rate slowing effects of intravascular adenosine in vivo. PLoS ONE 2009, 4, e6784.
  50. Sitkovsky, M.V.; Lukashev, D.; Apasov, S.; Kojima, H.; Koshiba, M.; Caldwell, C.; Ohta, A.; Thiel, M. Physiological control of immune response and inflammatory tissue damage by hypoxia-inducible factors and adenosine A2A receptors. Annu. Rev. Immunol. 2004, 22, 657–682.
  51. Ohta, A.; Sitkovsky, M. Role of G-protein-coupled adenosine receptors in downregulation of inflammation and protection from tissue damage. Nature 2001, 414, 916–920.
  52. Koscso, B.; Trepakov, A.; Csoka, B.; Nemeth, Z.H.; Pacher, P.; Eltzschig, H.K.; Hasko, G. Stimulation of A2B adenosine receptors protects against trauma-hemorrhagic shock-induced lung injury. Purinergic Signal. 2013, 9, 427–432.
  53. Nemeth, Z.H.; Lutz, C.S.; Csoka, B.; Deitch, E.A.; Leibovich, S.J.; Gause, W.C.; Tone, M.; Pacher, P.; Vizi, E.S.; Hasko, G. Adenosine augments IL-10 production by macrophages through an A2B receptor-mediated posttranscriptional mechanism. J. Immunol. 2005, 175, 8260–8270.
  54. Cronstein, B.N.; Daguma, L.; Nichols, D.; Hutchison, A.J.; Williams, M. The adenosine/neutrophil paradox resolved: Human neutrophils possess both A1 and A2 receptors that promote chemotaxis and inhibit O2 generation, respectively. J. Clin. Investig. 1990, 85, 1150–1157.
  55. Hasko, G.; Linden, J.; Cronstein, B.; Pacher, P. Adenosine receptors: Therapeutic aspects for inflammatory and immune diseases. Nat. Rev. Drug Discov. 2008, 7, 759–770.
  56. Hasko, G.; Cronstein, B.N. Adenosine: An endogenous regulator of innate immunity. Trends Immunol. 2004, 25, 33–39.
  57. Loffler, M.; Morote-Garcia, J.C.; Eltzschig, S.A.; Coe, I.R.; Eltzschig, H.K. Physiological roles of vascular nucleoside transporters. Arter. Thromb. Vasc. Biol. 2007, 27, 1004–1013.
  58. Le, T.T.; Berg, N.K.; Harting, M.T.; Li, X.; Eltzschig, H.K.; Yuan, X. Purinergic Signaling in Pulmonary Inflammation. Front. Immunol. 2019, 10, 1633.
  59. Zhang, Y.; Dai, Y.; Wen, J.; Zhang, W.; Grenz, A.; Sun, H.; Tao, L.; Lu, G.; Alexander, D.C.; Milburn, M.V.; et al. Detrimental effects of adenosine signaling in sickle cell disease. Nat. Med. 2011, 17, 79–86.
  60. Van Linden, A.; Eltzschig, H.K. Role of pulmonary adenosine during hypoxia: Extracellular generation, signaling and metabolism by surface adenosine deaminase/CD26. Expert Opin. Biol. Ther. 2007, 7, 1437–1447.
  61. Eltzschig, H.K.; Faigle, M.; Knapp, S.; Karhausen, J.; Ibla, J.; Rosenberger, P.; Odegard, K.C.; Laussen, P.C.; Thompson, L.F.; Colgan, S.P. Endothelial catabolism of extracellular adenosine during hypoxia: The role of surface adenosine deaminase and CD26. Blood 2006, 108, 1602–1610.
  62. Eltzschig, H.K.; Eckle, T.; Mager, A.; Kuper, N.; Karcher, C.; Weissmuller, T.; Boengler, K.; Schulz, R.; Robson, S.C.; Colgan, S.P. ATP release from activated neutrophils occurs via connexin 43 and modulates adenosine-dependent endothelial cell function. Circ. Res. 2006, 99, 1100–1108.
  63. Eltzschig, H.K.; Macmanus, C.F.; Colgan, S.P. Neutrophils as Sources of Extracellular Nucleotides: Functional Consequences at the Vascular Interface. Trends Cardiovasc. Med. 2008, 18, 103–107.
  64. Faigle, M.; Seessle, J.; Zug, S.; El Kasmi, K.C.; Eltzschig, H.K. ATP release from vascular endothelia occurs across Cx43 hemichannels and is attenuated during hypoxia. PLoS ONE 2008, 3, e2801.
  65. Chekeni, F.B.; Elliott, M.R.; Sandilos, J.K.; Walk, S.F.; Kinchen, J.M.; Lazarowski, E.R.; Armstrong, A.J.; Penuela, S.; Laird, D.W.; Salvesen, G.S.; et al. Pannexin 1 channels mediate ‘find-me’ signal release and membrane permeability during apoptosis. Nature 2010, 467, 863–867.
  66. Ravichandran, K.S. Beginnings of a good apoptotic meal: The find-me and eat-me signaling pathways. Immunity 2011, 35, 445–455.
  67. Elliott, M.R.; Chekeni, F.B.; Trampont, P.C.; Lazarowski, E.R.; Kadl, A.; Walk, S.F.; Park, D.; Woodson, R.I.; Ostankovich, M.; Sharma, P.; et al. Nucleotides released by apoptotic cells act as a find-me signal to promote phagocytic clearance. Nature 2009, 461, 282–286.
  68. Antonioli, L.; Pacher, P.; Vizi, E.S.; Hasko, G. CD39 and CD73 in immunity and inflammation. Trends Mol. Med. 2013, 19, 355–367.
  69. Kaczmarek, E.; Koziak, K.; Sevigny, J.; Siegel, J.B.; Anrather, J.; Beaudoin, A.R.; Bach, F.H.; Robson, S.C. Identification and characterization of CD39/vascular ATP diphosphohydrolase. J. Biol. Chem. 1996, 271, 33116–33122.
  70. Enjyoji, K.; Sevigny, J.; Lin, Y.; Frenette, P.S.; Christie, P.D.; Esch, J.S., 2nd; Imai, M.; Edelberg, J.M.; Rayburn, H.; Lech, M.; et al. Targeted disruption of cd39/ATP diphosphohydrolase results in disordered hemostasis and thromboregulation. Nat. Med. 1999, 5, 1010–1017.
  71. Kohler, D.; Eckle, T.; Faigle, M.; Grenz, A.; Mittelbronn, M.; Laucher, S.; Hart, M.L.; Robson, S.C.; Muller, C.E.; Eltzschig, H.K. CD39/ectonucleoside triphosphate diphosphohydrolase 1 provides myocardial protection during cardiac ischemia/reperfusion injury. Circulation 2007, 116, 1784–1794.
  72. Eckle, T.; Grenz, A.; Kohler, D.; Redel, A.; Falk, M.; Rolauffs, B.; Osswald, H.; Kehl, F.; Eltzschig, H.K. Systematic evaluation of a novel model for cardiac ischemic preconditioning in mice. Am. J. Physiol. Circ. Physiol. 2006, 291, H2533–H2540.
  73. Murry, C.E.; Jennings, R.B.; Reimer, K.A. Preconditioning with ischemia: A delay of lethal cell injury in ischemic myocardium. Circulation 1986, 74, 1124–1136.
  74. Eltzschig, H.K.; Weissmuller, T.; Mager, A.; Eckle, T. Nucleotide metabolism and cell-cell interactions. Methods Mol. Biol. 2006, 341, 73–87.
  75. Eltzschig, H.K.; Ibla, J.C.; Furuta, G.T.; Leonard, M.O.; Jacobson, K.A.; Enjyoji, K.; Robson, S.C.; Colgan, S.P. Coordinated adenine nucleotide phosphohydrolysis and nucleoside signaling in posthypoxic endothelium: Role of ectonucleotidases and adenosine A2B receptors. J. Exp. Med. 2003, 198, 783–796.
  76. Synnestvedt, K.; Furuta, G.T.; Comerford, K.M.; Louis, N.; Karhausen, J.; Eltzschig, H.K.; Hansen, K.R.; Thompson, L.F.; Colgan, S.P. Ecto-5’-nucleotidase (CD73) regulation by hypoxia-inducible factor-1 mediates permeability changes in intestinal epithelia. J. Clin. Investig. 2002, 110, 993–1002.
  77. Eckle, T.; Fullbier, L.; Wehrmann, M.; Khoury, J.; Mittelbronn, M.; Ibla, J.; Rosenberger, P.; Eltzschig, H.K. Identification of ectonucleotidases CD39 and CD73 in innate protection during acute lung injury. J. Immunol. 2007, 178, 8127–8137.
  78. Eltzschig, H.K.; Thompson, L.F.; Karhausen, J.; Cotta, R.J.; Ibla, J.C.; Robson, S.C.; Colgan, S.P. Endogenous adenosine produced during hypoxia attenuates neutrophil accumulation: Coordination by extracellular nucleotide metabolism. Blood 2004, 104, 3986–3992.
  79. Hart, M.L.; Gorzolla, I.C.; Schittenhelm, J.; Robson, S.C.; Eltzschig, H.K. SP1-dependent induction of CD39 facilitates hepatic ischemic preconditioning. J. Immunol. 2010, 184, 4017–4024.
  80. Eltzschig, H.K.; Kohler, D.; Eckle, T.; Kong, T.; Robson, S.C.; Colgan, S.P. Central role of Sp1-regulated CD39 in hypoxia/ischemia protection. Blood 2009, 113, 224–232.
  81. Colgan, S.P.; Eltzschig, H.K.; Eckle, T.; Thompson, L.F. Physiological roles for ecto-5’-nucleotidase (CD73). Purinergic Signal. 2006, 2, 351–360.
  82. Thompson, L.F.; Eltzschig, H.K.; Ibla, J.C.; Van De Wiele, C.J.; Resta, R.; Morote-Garcia, J.C.; Colgan, S.P. Crucial role for ecto-5’-nucleotidase (CD73) in vascular leakage during hypoxia. J. Exp. Med. 2004, 200, 1395–1405.
  83. Eckle, T.; Krahn, T.; Grenz, A.; Kohler, D.; Mittelbronn, M.; Ledent, C.; Jacobson, M.A.; Osswald, H.; Thompson, L.F.; Unertl, K.; et al. Cardioprotection by ecto-5’-nucleotidase (CD73) and A2B adenosine receptors. Circulation 2007, 115, 1581–1590.
  84. Reichelt, M.E.; Willems, L.; Molina, J.G.; Sun, C.X.; Noble, J.C.; Ashton, K.J.; Schnermann, J.; Blackburn, M.R.; Headrick, J.P. Genetic deletion of the A1 adenosine receptor limits myocardial ischemic tolerance. Circ. Res. 2005, 96, 363–367.
  85. Auchampach, J.A.; Jin, X.; Moore, J.; Wan, T.C.; Kreckler, L.M.; Ge, Z.D.; Narayanan, J.; Whalley, E.; Kiesman, W.; Ticho, B.; et al. Comparison of three different A1 adenosine receptor antagonists on infarct size and multiple cycle ischemic preconditioning in anesthetized dogs. J. Pharmacol. Exp. Ther. 2004, 308, 846–856.
  86. Takano, H.; Bolli, R.; Black, R.G., Jr.; Kodani, E.; Tang, X.L.; Yang, Z.; Bhattacharya, S.; Auchampach, J.A. A(1) or A(3) adenosine receptors induce late preconditioning against infarction in conscious rabbits by different mechanisms. Circ. Res. 2001, 88, 520–528.
  87. Eckle, T.; Faigle, M.; Grenz, A.; Laucher, S.; Thompson, L.F.; Eltzschig, H.K. A2B adenosine receptor dampens hypoxia-induced vascular leak. Blood 2008, 111, 2024–2035.
  88. Revan, S.; Montesinos, M.C.; Naime, D.; Landau, S.; Cronstein, B.N. Adenosine A2 receptor occupancy regulates stimulated neutrophil function via activation of a serine/threonine protein phosphatase. J. Biol. Chem. 1996, 271, 17114–17118.
  89. Liu, H.; Zhang, Y.; Wu, H.; D’Alessandro, A.; Yegutkin, G.G.; Song, A.; Sun, K.; Li, J.; Cheng, N.Y.; Huang, A.; et al. Beneficial Role of Erythrocyte Adenosine A2B Receptor-Mediated AMP-Activated Protein Kinase Activation in High-Altitude Hypoxia. Circulation 2016, 134, 405–421.
  90. Song, A.; Zhang, Y.; Han, L.; Yegutkin, G.G.; Liu, H.; Sun, K.; D’Alessandro, A.; Li, J.; Karmouty-Quintana, H.; Iriyama, T.; et al. Erythrocytes retain hypoxic adenosine response for faster acclimatization upon re-ascent. Nat. Commun. 2017, 8, 14108.
  91. Hoegl, S.; Brodsky, K.S.; Blackburn, M.R.; Karmouty-Quintana, H.; Zwissler, B.; Eltzschig, H.K. Alveolar Epithelial A2B Adenosine Receptors in Pulmonary Protection during Acute Lung Injury. J. Immunol. 2015, 195, 1815–1824.
  92. Eckle, T.; Hughes, K.; Ehrentraut, H.; Brodsky, K.S.; Rosenberger, P.; Choi, D.S.; Ravid, K.; Weng, T.; Xia, Y.; Blackburn, M.R.; et al. Crosstalk between the equilibrative nucleoside transporter ENT2 and alveolar Adora2b adenosine receptors dampens acute lung injury. FASEB J. 2013, 27, 3078–3089.
  93. Hesse, J.; Groterath, W.; Owenier, C.; Steinhausen, J.; Ding, Z.; Steckel, B.; Czekelius, C.; Alter, C.; Marzoq, A.; Schrader, J. Normoxic induction of HIF-1alpha by adenosine-A2B R signaling in epicardial stromal cells formed after myocardial infarction. FASEB J. 2021, 35, e21517.
  94. Aherne, C.M.; Saeedi, B.; Collins, C.B.; Masterson, J.C.; McNamee, E.N.; Perrenoud, L.; Rapp, C.R.; Curtis, V.F.; Bayless, A.; Fletcher, A.; et al. Epithelial-specific A2B adenosine receptor signaling protects the colonic epithelial barrier during acute colitis. Mucosal. Immunol. 2015, 8, 699.
  95. Ehrentraut, H.; Westrich, J.A.; Eltzschig, H.K.; Clambey, E.T. Adora2b Adenosine Receptor Engagement Enhances Regulatory T Cell Abundance during Endotoxin-Induced Pulmonary Inflammation. PLoS ONE 2012, 7, e32416.
  96. Lu, B.; Rajakumar, S.V.; Robson, S.C.; Lee, E.K.; Crikis, S.; d’Apice, A.J.; Cowan, P.J.; Dwyer, K.M. The impact of purinergic signaling on renal ischemia-reperfusion injury. Transplantation 2008, 86, 1707–1712.
  97. Deaglio, S.; Dwyer, K.M.; Gao, W.; Friedman, D.; Usheva, A.; Erat, A.; Chen, J.F.; Enjyoji, K.; Linden, J.; Oukka, M.; et al. Adenosine generation catalyzed by CD39 and CD73 expressed on regulatory T cells mediates immune suppression. J. Exp. Med. 2007, 204, 1257–1265.
  98. Alter, C.; Ding, Z.; Flogel, U.; Scheller, J.; Schrader, J. A2bR-dependent signaling alters immune cell composition and enhances IL-6 formation in the ischemic heart. Am. J. Physiol. Heart Circ. Physiol. 2019, 317, H190–H200.
  99. Kong, T.; Westerman, K.A.; Faigle, M.; Eltzschig, H.K.; Colgan, S.P. HIF-dependent induction of adenosine A2B receptor in hypoxia. FASEB J. 2006, 20, 2242–2250.
  100. Eckle, T.; Kewley, E.M.; Brodsky, K.S.; Tak, E.; Bonney, S.; Gobel, M.; Anderson, D.; Glover, L.E.; Riegel, A.K.; Colgan, S.P.; et al. Identification of hypoxia-inducible factor HIF-1A as transcriptional regulator of the A2B adenosine receptor during acute lung injury. J. Immunol. 2014, 192, 1249–1256.
  101. Ahmad, A.; Ahmad, S.; Glover, L.; Miller, S.M.; Shannon, J.M.; Guo, X.; Franklin, W.A.; Bridges, J.P.; Schaack, J.B.; Colgan, S.P.; et al. Adenosine A2A receptor is a unique angiogenic target of HIF-2alpha in pulmonary endothelial cells. Proc. Natl. Acad. Sci. USA 2009, 106, 10684–10689.
  102. Yang, Z.; Day, Y.J.; Toufektsian, M.C.; Ramos, S.I.; Marshall, M.; Wang, X.Q.; French, B.A.; Linden, J. Infarct-sparing effect of A2A-adenosine receptor activation is due primarily to its action on lymphocytes. Circulation 2005, 111, 2190–2197.
  103. Yang, Z.; Day, Y.J.; Toufektsian, M.C.; Xu, Y.; Ramos, S.I.; Marshall, M.A.; French, B.A.; Linden, J. Myocardial infarct-sparing effect of adenosine A2A receptor activation is due to its action on CD4+ T lymphocytes. Circulation 2006, 114, 2056–2064.
  104. Maas, J.E.; Wan, T.C.; Figler, R.A.; Gross, G.J.; Auchampach, J.A. Evidence that the acute phase of ischemic preconditioning does not require signaling by the A 2B adenosine receptor. J. Mol. Cell. Cardiol. 2010, 49, 886–893.
  105. Seo, S.W.; Koeppen, M.; Bonney, S.; Gobel, M.; Thayer, M.; Harter, P.N.; Ravid, K.; Eltzschig, H.K.; Mittelbronn, M.; Walker, L.; et al. Differential Tissue-Specific Function of Adora2b in Cardioprotection. J. Immunol. 2015, 195, 1732–1743.
  106. Koeppen, M.; Harter, P.N.; Bonney, S.; Bonney, M.; Reithel, S.; Zachskorn, C.; Mittelbronn, M.; Eckle, T. Adora2b Signaling on Bone Marrow Derived Cells Dampens Myocardial Ischemia-Reperfusion Injury. Anesthesiology 2012, 116, 1245–1257.
  107. Bonney, S.; Kominsky, D.; Brodsky, K.; Eltzschig, H.; Walker, L.; Eckle, T. Cardiac Per2 functions as novel link between fatty acid metabolism and myocardial inflammation during ischemia and reperfusion injury of the heart. PLoS ONE 2013, 8, e71493.
  108. Ruan, W.; Yuan, X.; Eltzschig, H. Circadian Mechanisms in Medicine. N. Engl. J. Med. 2021, 384, e76.
  109. Ruan, W.; Yuan, X.; Eltzschig, H.K. Circadian rhythm as a therapeutic target. Nat. Rev. Drug Discov. 2021, 20, 287–307.
  110. Keller, M.; Mirakaj, V.; Koeppen, M.; Rosenberger, P. Neuronal guidance proteins in cardiovascular inflammation. Basic Res. Cardiol. 2021, 116, 6.
  111. Mirakaj, V.; Gatidou, D.; Potzsch, C.; Konig, K.; Rosenberger, P. Netrin-1 signaling dampens inflammatory peritonitis. J. Immunol. 2011, 186, 549–555.
  112. Mirakaj, V.; Thix, C.A.; Laucher, S.; Mielke, C.; Morote-Garcia, J.C.; Schmit, M.A.; Henes, J.; Unertl, K.E.; Kohler, D.; Rosenberger, P. Netrin-1 dampens pulmonary inflammation during acute lung injury. Am. J. Respir. Crit. Care Med. 2010, 181, 815–824.
  113. Serafini, T.; Colamarino, S.A.; Leonardo, E.D.; Wang, H.; Beddington, R.; Skarnes, W.C.; Tessier-Lavigne, M. Netrin-1 is required for commissural axon guidance in the developing vertebrate nervous system. Cell 1996, 87, 1001–1014.
  114. Serafini, T.; Kennedy, T.E.; Galko, M.J.; Mirzayan, C.; Jessell, T.M.; Tessier-Lavigne, M. The netrins define a family of axon outgrowth-promoting proteins homologous to C. elegans UNC-6. Cell 1994, 78, 409–424.
  115. Varadarajan, S.G.; Kong, J.H.; Phan, K.D.; Kao, T.J.; Panaitof, S.C.; Cardin, J.; Eltzschig, H.; Kania, A.; Novitch, B.G.; Butler, S.J. Netrin1 Produced by Neural Progenitors, Not Floor Plate Cells, Is Required for Axon Guidance in the Spinal Cord. Neuron 2017, 94, 790–799.e3.
  116. Gao, R.; Peng, X.; Perry, C.; Sun, H.; Ntokou, A.; Ryu, C.; Gomez, J.L.; Reeves, B.C.; Walia, A.; Kaminski, N.; et al. Macrophage-derived netrin-1 drives adrenergic nerve-associated lung fibrosis. J. Clin. Investig. 2021, 131, e136542.
  117. Moore, S.W.; Tessier-Lavigne, M.; Kennedy, T.E. Netrins and their receptors. Adv. Exp. Med. Biol. 2007, 621, 17–31.
  118. Hadi, T.; Boytard, L.; Silvestro, M.; Alebrahim, D.; Jacob, S.; Feinstein, J.; Barone, K.; Spiro, W.; Hutchison, S.; Simon, R.; et al. Macrophage-derived netrin-1 promotes abdominal aortic aneurysm formation by activating MMP3 in vascular smooth muscle cells. Nat. Commun. 2018, 9, 5022.
  119. Mirakaj, V.; Rosenberger, P. Immunomodulatory Functions of Neuronal Guidance Proteins. Trends Immunol. 2017, 38, 444–456.
  120. Corset, V.; Nguyen-Ba-Charvet, K.T.; Forcet, C.; Moyse, E.; Chedotal, A.; Mehlen, P. Netrin-1-mediated axon outgrowth and cAMP production requires interaction with adenosine A2b receptor. Nature 2000, 407, 747–750.
  121. Chen, Z.; Chen, Y.; Zhou, J.; Li, Y.; Gong, C.; Wang, X. Netrin-1 reduces lung ischemia-reperfusion injury by increasing the proportion of regulatory T cells. J. Int. Med. Res. 2020, 48, 300060520926415.
  122. He, J.; Zhao, Y.; Deng, W.; Wang, D.X. Netrin-1 promotes epithelial sodium channel-mediated alveolar fluid clearance via activation of the adenosine 2B receptor in lipopolysaccharide-induced acute lung injury. Respiration 2014, 87, 394–407.
  123. Aherne, C.M.; Collins, C.B.; Eltzschig, H.K. Netrin-1 guides inflammatory cell migration to control mucosal immune responses during intestinal inflammation. Tissue Barriers 2013, 1, e24957.
  124. Aherne, C.M.; Collins, C.B.; Masterson, J.C.; Tizzano, M.; Boyle, T.A.; Westrich, J.A.; Parnes, J.A.; Furuta, G.T.; Rivera-Nieves, J.; Eltzschig, H.K. Neuronal guidance molecule netrin-1 attenuates inflammatory cell trafficking during acute experimental colitis. Gut 2012, 61, 695–705.
  125. Tak, E.; Ridyard, D.; Badulak, A.; Giebler, A.; Shabeka, U.; Werner, T.; Clambey, E.; Moldovan, R.; Zimmerman, M.A.; Eltzschig, H.K.; et al. Protective role for netrin-1 during diabetic nephropathy. J. Mol. Med. 2013, 91, 1071–1080.
  126. Zhang, Y.; Chen, P.; Di, G.; Qi, X.; Zhou, Q.; Gao, H. Netrin-1 promotes diabetic corneal wound healing through molecular mechanisms mediated via the adenosine 2B receptor. Sci. Rep. 2018, 8, 5994.
  127. Li, J.; Conrad, C.; Mills, T.W.; Berg, N.K.; Kim, B.; Ruan, W.; Lee, J.W.; Zhang, X.; Yuan, X.; Eltzschig, H.K. PMN-derived netrin-1 attenuates cardiac ischemia-reperfusion injury via myeloid ADORA2B signaling. J. Exp. Med. 2021, 218, e20210008.
  128. Stein, E.; Zou, Y.; Poo, M.; Tessier-Lavigne, M. Binding of DCC by netrin-1 to mediate axon guidance independent of adenosine A2B receptor activation. Science 2001, 291, 1976–1982.
  129. Rosenberger, P.; Schwab, J.M.; Mirakaj, V.; Masekowsky, E.; Mager, A.; Morote-Garcia, J.C.; Unertl, K.; Eltzschig, H.K. Hypoxia-inducible factor-dependent induction of netrin-1 dampens inflammation caused by hypoxia. Nat. Immunol. 2009, 10, 195–202.
  130. Ramkhelawon, B.; Yang, Y.; van Gils, J.M.; Hewing, B.; Rayner, K.J.; Parathath, S.; Guo, L.; Oldebeken, S.; Feig, J.L.; Fisher, E.A.; et al. Hypoxia induces netrin-1 and Unc5b in atherosclerotic plaques: Mechanism for macrophage retention and survival. Arterioscler. Thromb. Vasc. Biol. 2013, 33, 1180–1188.
  131. Griffiths, M.; Beaumont, N.; Yao, S.Y.; Sundaram, M.; Boumah, C.E.; Davies, A.; Kwong, F.Y.; Coe, I.; Cass, C.E.; Young, J.D.; et al. Cloning of a human nucleoside transporter implicated in the cellular uptake of adenosine and chemotherapeutic drugs. Nat. Med. 1997, 3, 89–93.
  132. Picano, E.; Trivieri, M.G. Pharmacologic stress echocardiography in the assessment of coronary artery disease. Curr. Opin. Cardiol. 1999, 14, 464–470.
  133. Sicari, R.; Cortigiani, L.; Bigi, R.; Landi, P.; Raciti, M.; Picano, E. Prognostic value of pharmacological stress echocardiography is affected by concomitant antiischemic therapy at the time of testing. Circulation 2004, 109, 2428–2431.
  134. Wang, W.; Chen, N.Y.; Ren, D.; Davies, J.; Philip, K.; Eltzschig, H.K.; Blackburn, M.R.; Akkanti, B.; Karmouty-Quintana, H.; Weng, T. Enhancing Extracellular Adenosine Levels Restores Barrier Function in Acute Lung Injury Through Expression of Focal Adhesion Proteins. Front. Mol. Biosci. 2021, 8, 636678.
  135. Aherne, C.M.; Collins, C.B.; Rapp, C.R.; Olli, K.E.; Perrenoud, L.; Jedlicka, P.; Bowser, J.L.; Mills, T.W.; Karmouty-Quintana, H.; Blackburn, M.R.; et al. Coordination of ENT2-dependent adenosine transport and signaling dampens mucosal inflammation. JCI Insight 2018, 3, e121521.
  136. Morote-Garcia, J.C.; Kohler, D.; Roth, J.M.; Mirakaj, V.; Eldh, T.; Eltzschig, H.K.; Rosenberger, P. Repression of the equilibrative nucleoside transporters dampens inflammatory lung injury. Am. J. Respir. Cell Mol. Biol. 2013, 49, 296–305.
  137. Rose, J.B.; Naydenova, Z.; Bang, A.; Ramadan, A.; Klawitter, J.; Schram, K.; Sweeney, G.; Grenz, A.; Eltzschig, H.; Hammond, J.; et al. Absence of equilibrative nucleoside transporter 1 in ENT1 knockout mice leads to altered nucleoside levels following hypoxic challenge. Life Sci. 2011, 89, 621–630.
  138. Kitakaze, M.; Minamino, T.; Node, K.; Takashima, S.; Funaya, H.; Kuzuya, T.; Hori, M. Adenosine and cardioprotection in the diseased heart. Jpn. Circ. J. 1999, 63, 231–243.
  139. Miura, T.; Ogawa, T.; Iwamoto, T.; Shimamoto, K.; Iimura, O. Dipyridamole potentiates the myocardial infarct size-limiting effect of ischemic preconditioning. Circulation 1992, 86, 979–985.
  140. Morote-Garcia, J.C.; Rosenberger, P.; Kuhlicke, J.; Eltzschig, H.K. HIF-1-dependent repression of adenosine kinase attenuates hypoxia-induced vascular leak. Blood 2008, 111, 5571–5580.
  141. Peart, J.N.; Gross, G.J. Cardioprotection following adenosine kinase inhibition in rat hearts. Basic Res. Cardiol. 2005, 100, 328–336.
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