Adenosine Signaling-Mediated Metabolic Reprogramming Regulates Erythropoiesis

Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 2437-2437 ◽  
Author(s):  
Hong Liu ◽  
Yujin Zhang ◽  
Angelo D'Alessandro ◽  
Travis Nemkov ◽  
Jacob Couturier ◽  
...  
Keyword(s):  
High Altitude ◽  
Metabolic Flux ◽  
Metabolic Reprogramming ◽  
Glutamine Metabolism ◽  
Dependent Manner ◽  
Erythroid Progenitor ◽  
Hematopoietic Stem ◽  
Stress Erythropoiesis ◽  
Human And Mouse ◽  
Adenosine Signaling

Abstract Erythropoiesis is an extremely dynamic process finely regulated by cytokines, hormones, and growth factors at transcriptional and translational levels. Stress-induced erythropoiesis is defined as a stimulated basal erythropoiesis with expansion of the erythroid progenitor pool, associated with reticulocytosis and splenomegaly. Stress erythropoiesis is stimulated under the condition of insufficient oxygen availability such as high altitude, blood loss, infection, and anemia. Thus, stress erythropoiesis is an important stress adaptive response for survival. Although stress erythropoiesis has been long speculated to be linked with increased metabolic requirements, until recent two years with innovative metabolomics profiling and state of art isotopically labelled metabolic flux approaches, the filed has evolved and revealed that enhanced glucose and glutamine metabolism is essential for stress erythropoiesis. However, molecular basis underlying metabolic reprogramming to enhance glucose metabolism and subsequently stress erythropoiesis remains unclear. To address this question, we conducted both human and mouse studies. First, we found that plasma adenosine is rapidly induced and associated with stress erythropoiesis features including increased hematocrit (HCT), hemoglobin (Hb) mass and reticulocytes in healthy human volunteers at high altitude and in mice exposed to hypoxia mimicking high altitude. Follow-up mouse genetic studies showed that activation of adenosine signaling via erythroid ADORA2B promotes the survival and expansion of proerythroblasts both in spleen and bone marrow and in this way contributes to hypoxia-induced stress erythropoiesis independent of erythropoietin. Using unbiased high-throughput metabolic profiling, we identified that erythroid ADORA2B contributes to an overall hypoxia metabolic reprogramming with substantial increased glycolysis in proerythroblast progenitors in mice. Finally, using primary human CD34+ hematopoietic stem cells culture, we showed that adenosine analogue and ADORA2B agonist promote the survival and expansion of erythroid progenitors in a time and dose-dependent manner. Taken together, both human and mouse studies identify that adenosine ADORA2B is a previously unrecognized purinergic signaling underlying hypoxia-induced erythropoiesis by facilitating expansion and survival of proerythroblasts, and highlight that enhancing this pathway is a potential strategy to induce erythropoiesis. Disclosures No relevant conflicts of interest to declare.

scholarly journals Adenosine A2B Receptor Controls Erythroid Lineage Commitment in Stress Erythropoiesis By Promoting Metabolic Reprogramming

Blood ◽  
2018 ◽  
Vol 132 (Supplement 1) ◽  
pp. 845-845
Author(s):  
Hong Liu ◽  
Rongrong Liu ◽  
Travis Nemkov ◽  
Jacob Couturier ◽  
Long Liang ◽  
...  
Keyword(s):  
Gene Expression ◽  
Metabolic Reprogramming ◽  
Lineage Commitment ◽  
Erythroid Progenitor ◽  
Adenosine A2b Receptor ◽  
Stress Erythropoiesis ◽  
Human Cd34 ◽  
Induced Stress ◽  
A2b Receptor ◽  
Adenosine A2b

Abstract Insufficient oxygen availability under stress conditions including hypoxia and anemia is a major stimulus for stress erythropoiesis. Adenosine is known to be induced under hypoxia and energy depletion. Increased adenosine signaling via its specific receptors regulates multiple cellular functions including anti-inflamation, anti-vascular leakage and vasodilation. However, its function in stress erythropoiesis and underlying mechanisms are enigmatic. Among four adenosine receptors, we report that adenosine A2B receptor (ADORA2B) is expressed at a significant higher level in megakaryocyte-erythroid progenitor (MEP) compared to common pluoripotent progenitors (CMP) or granulocyte-erythroid progenitor (GMP) in undifferentiated human CD34+. To determine the function role of ADORA2B in stress erythropoiesis, we generated erythroid Adora2b specific knockouts by crossing Adora2bf/fmice with EpoR-Cre+mice. First, we demonstrated that EpoR specifically ablated ADORA2B gene only in MEP but not in CMP or GMP lineages. Next, we challenged EpoR-Cre+mice (control) and Adora2bf/fEpoR-Cre+ mice (erythroid specific ablation of Adora2b genes) with hypoxia. We discovered that genetic deletion of ADORA2B at MEP stage blocked erythroid vs myeloid commitment under hypoxia-induced stress erythropoiesis. Further metabolic profiling revealed that ADORA2B activation regulated erythroid lineage commitment by promoting glucose uptake and erythroid metabolic reprogramming channelling glucose metabolism toward the pentose phosphate pathway (PPP) rather than glycolysis to generate more ribose phosphate as well as facilitate glutamine uptake to serve as a nitrogen donor for de novo nucleotide biosynthesis. Meanwhile, ADORA2B-stimulated glutaminolysis increased TCA cycle intermediates and thus increased energy production under stress erythropoiesis. We further demonstrated that ADORA2B on MEP is also important for erythroid commitment in response to PHZ-induced mouse model. Followup studies revealed that HIF-1a is induced in erythroid progenitors in a ADORA2B-dependent manner and ablation of HIF-1a only in MEP but not in CMP or GMP attenuated erythroid lineage commitment in both hypoxia-induced and anemia-induced stress erythropoiesis mouse models. Moreover, we showed that ADORA2B-triggered metabolic reprogramming depended on HIF-1a-preferentially upregulated gene expression of transporters for glucose and glutamine and key enyzmes of PPP and glutaminolysis over glycolytic enzymes. Similar to mouse studies, in cultured Epo-stimulated human CD34+ hematopoietic stem progenitor cells, enhancing ADORA2B signaling induced gene expression of the transporters for glucose and glutamine, key enzymes of PPP and glutaminolysis over glycolysis and thus controlled the commitment to erythrioid versus myeloid lineage and in turn promoted erythroid colony formation including BFU-E, CFU-E versus CFU-GM. Further studies showed that inhibition of HIF-1a by Chrysin significantly attenuated ADORA2B activation-induced upregulation of gene expression of the transporters of glucose and glutamine, metabolic enzymes and thus reduces erythroic commitment and BFU-E and CFU-E in Epo-stimualted CD34+ HPSCs. Overall, using multidisciplinary approaches including mouse genetics, metabolomics, isotopically labelled glucose and glutamine flux analysis, human CD34+ HPSCs and pharmacological studies, we provide both mouse and human evidence that ADORA2B is a missing cofactor controlling erythroid lineage commitment in stress erythropoiesis via HIF-1a-dependent upregulation of key genes to promote metabolic reprogramming. These findings add significant new insights to erythroid commitment and immediately provide new strategies for regulating stress erythropoiesis. Disclosures Nemkov: Omix Technologies inc: Equity Ownership.

Neuromedin U Peptide Activates STAT5 and S6 in a JAK-2 Dependent Manner and Promotes Erythroid Cell Growth in Primary Erythroid Progenitor Cells

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 1241-1241
Author(s):  
Rebecca Lenzo ◽  
Martha Dua-Awereh ◽  
Martin Carroll ◽  
Susan E. Shetzline
Keyword(s):  
Cell Growth ◽  
Progenitor Cells ◽  
Surrogate Marker ◽  
Janus Kinase ◽  
Erythroid Cell ◽  
Dependent Manner ◽  
Erythroid Progenitor ◽  
Hematopoietic Stem ◽  
Erythroid Progenitor Cells ◽  
Pi3k Activation

Abstract Abstract 1241 Erythropoiesis is a multi-step process during which hematopoietic stem cells terminally differentiate into red blood cells (RBCs). Erythropoietin (EPO) is the only known cytokine regulator of terminal erythroid differentiation. Previously, we reported that the neuropeptide, neuromedin U (NmU), which interacts with NmU receptor type 1 (NMUR1), functions as a novel extracellular cofactor with EPO to promote the expansion of early erythroblasts, which are CD34−, CD71+, glycophorin A (GlyA)dim(Gambone et al, Blood. 2011). Here, we describe studies to understand the mechanism whereby NmU augments EPO effects on erythroid cell growth. EPO triggers Janus kinase (Jak)-2 dependent activation of signal transducer and activator of transcription (STAT) 5 and phosphatidylinositol 3-kinase (PI3K) to promote the proliferation and/or survival of erythroid progenitor cells. We hypothesized that NmU peptide would cooperate with EPO to promote the proliferation of early erythroblasts through STAT5 and/or PI3K activation. To address this hypothesis, we cultured primary human CD34+ cells in 2-stage liquid culture with IL-3, IL-6, and stem cell factor (SCF) from day 0 to day 6. On day 6, 2U/mL of EPO was added, and the cells were cultured for an additional 5 days to expand erythroid progenitors. On day 11, cells were briefly serum starved and then stimulated with EPO and/or NmU in the absence or presence of a Jak-1/2 inhibitor. Activation of STAT5 and S6, a surrogate marker for PI3K activation, were assessed by phospho-flow in ERY3 (CD34−, CD71+, GlyA+) and ERY4 (CD34−, CD71dim, GlyA+) cells. As expected, EPO alone activated STAT5 and S6 in ERY3 cells only, and the presence of a Jak-1/2 inhibitor diminished STAT5 activation. Interestingly, STAT5 and S6 were activated by NmU peptide alone in ERY3 and ERY4. Surprisingly, in the presence of a Jak-1/2 inhibitor, NmU peptide, which binds to NMUR1 a G-protein coupled receptor, did not activate STAT5 or S6 in ERY3 or 4 cells, suggesting that NmU functions through a JAK kinase in erythroid cells. No additive or synergistic activation of STAT5 and S6 is observed in the presence of both EPO and NmU peptide when EPO was used at a dose of 2 U/mL. The mechanism whereby NmU activates a JAK dependent signaling pathway is under investigation. Preliminary evidence suggests that EPO induces the physical association of NMUR1 with EPO receptor (EPOR). Taken together, we propose that NmU is a neuropeptide expressed in bone marrow cells that cooperates to regulate erythroid expansion during early erythropoiesis through the activation of cytokine receptor like signaling pathways and perhaps through direct interaction with EPOR. NmU may be useful in the clinical management of anemia in patients unresponsive to EPO or other erythroid-stimulating agents. Disclosures: No relevant conflicts of interest to declare.

scholarly journals Lack of Beta-1 Integrin Limits Stress Erythropoiesis and Splenomegaly in Beta-Thalassemia

Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 2196-2196
Author(s):  
Roberta Chessa ◽  
Ritama Gupta ◽  
Bart J Crielaard ◽  
Carla Casu ◽  
Rick Feldman ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Red Cells ◽  
Poly I:C ◽  
Beta Thalassemia ◽  
Spleen Weight ◽  
Erythroid Cells ◽  
Erythroid Progenitor ◽  
Hematopoietic Stem ◽  
Stress Erythropoiesis ◽  
The Impact

Abstract After blood loss, the production of red cells must be increased by stress erythropoiesis. This phenomenon is associated with increased proliferation and reduced differentiation of the erythroblasts, leading to a net increase in the number of progenitor erythroid cells and red cells (erythron). In normal conditions, after expansion of the pool of erythroblasts, these cells eventually differentiate to erythrocytes and the anemia resolves. However, in diseases such as β−thalassemia, production of healthy mature erythrocytes is impaired, resulting in anemia. Over time, the expansion, rather than the differentiation, of the erythron further exacerbates the ineffective erythropoiesis (IE), reducing the ability of the erythroid progenitors to generate erythrocytes. Interrupting the interaction between macrophages and erythroblasts (MEI) in thalassemia models is efficacious in reducing IE and alleviating the disease phenotype. We speculate that these molecules are also responsible for the homing of erythroid progenitor cells to extramedullary organs, such as the spleen and liver. Our studies in erythroblasts indicate that integrin beta−1 (Itgβ1) and also intracellular molecules such as focal adhesion kinase (Fak1), Talin−1 and Sharpin might play a role in stress erythropoiesis. Furthermore, there is increased interaction between Itgb1 and Fak1 in erythroblasts co−cultured with macrophages as demonstrated by immunocytochemistry and in vitro proximity ligation assays. In addition, targeting either Itgβ1 or Fak1 prevents expansion of erythroid cells when cultured in the presence of macrophages. Strikingly, using Itgβ1 together with Ter119 as selection parameters in flow cytometry, a distinct subset of erythroblasts, not discernable using CD44 or CD71, was observable, which we found to be part of the mixed orthochromatic erythroblast/reticulocyte population as determined with CD44 expression. Enucleation of erythroblasts was accompanied by a marked loss of Itgβ1 expression, indicating that Itgβ1 may be involved in erythroblast enucleation and differentiation. We crossed Hbbth3/+ mice with animals in which Itgβ1 or Fak1 were floxed and carrying an inducible Cre−recombinase (Mx1−Cre). From these animals, we investigated three different models; two obtained from breeding (Hbbth3/+−Itgβ1fl/fl−Mx1−Cre and Hbbth3/+−Fak1fl/fl−Mx1−Cre) and one by bone marrow transplant (BMT) of hematopoietic stem cells (HSCs) of Hbbth3/+−Itgβ1fl/fl −Mx1−Cre animals into wt mice to generate thalassemic animals that expressed the floxed Itgβ1 only in hematopoietic cells. After serial administration of Poly(I)−Poly(C) [poly(I:C)] the animals were analyzed for their erythropoiesis in the bone marrow and spleen. All the animals treated with poly(I:C) showed populations of Itgβ1 or Fak1 negative cells in the bone marrow and spleen. This indicated that all the HSCs were successfully depleted of the Itgβ1 or Fak1 gene. Interestingly, the spleen weight of all the treated animals was reduced, on average, 50% compared to untreated thalassemic mice. Similar results were seen also in Hbbth3/+−Itgβ1fl/fl−Mx1−Cre animals generated through BMT. Therefore, Itgβ1 and Fak1 might contribute to the pathophysiology of thalassemia and their removal might result in reduced stress erythropoiesis, erythroid proliferation and, as a consequence, amelioration of splenomegaly. Iron analysis and quantification of Erythroferrone (ERFE) are in progress to evaluate the impact of depleting Itgβ1 and Fak1 on these mechanisms. We are now in the process of identifying compounds that target MEI and, in particular, Itgβ1. Such molecules might be utilized for development of new treatments for thalassemia or additional disorders of aberrant erythropoiesis. Disclosures Feldman: Bayer ealthCare Phamaceuticals Inc.: Employment. Rivella:isis Pharmaceuticals: Consultancy; Merganser Biotech: Other: Stock options; Novartis Pharmaceuticals: Consultancy; Medgenics Pharmaceuticals: Consultancy; Bayer Healthcare: Consultancy, Research Funding.

Wnt/β-Catenin Pathway Affects the Cell-Fate Decisions of Hematopoietic Stem/Progenitor Cells Modulating the Epigenetic States of Various Essential Transcription Factors

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 2433-2433
Author(s):  
Hirokazu Tanaka ◽  
Itaru Matsumura ◽  
Yusuke Satoh ◽  
Sachiko Ezoe ◽  
Tatsutoshi Nakahata ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Dependent Manner ◽  
Erythroid Progenitor ◽  
Self Renewal ◽  
Hematopoietic Stem ◽  
Myeloid Progenitor ◽  
Cd34 Cells ◽  
Canonical Wnt ◽  
Dose Dependent ◽  
Essential Transcription Factor

Abstract Several reports have implicated canonical Wnt/β-catenin pathway in murine and human hematopoietic stem/progenitor cells (HSC/HPCs) ex vivo expansion. In addition, it was demonstrated augmentation of hematopoietic repopulating ability in vivo by post transplantation treatment with an ATP-competitive GSK-3 inhibitor, which leads to activation of intrinsic β-catenin. Conversely, it is also reported that constitutive activation of β-catenin enforced cell cycle entry of murine HSCs, thereby, exhausting the long-term repopulating cell pool and leading to hematopoietic failure associated with loss of multilineage differentiation. In this way, the precise roles of individual molecules concerning in canonical Wnt/β-catenin pathway for normal hematopoiesis have not been elucidated. In this study, we examined the effects of GSK-3 inhibition on stem-cell maintenance, progenitor cell expansion, and lineage decisions of murine and human HSC/HPCs. At first, the expression and localization of β-catenin in human CD34+ HSC/HPCs treated with GSK-3 inhibitor 9 (6-bromoindirubin-3-oxime) (GI9) was observed with confocal microscopy. After the treatment for 24 hrs, expression of β-catenin in vehicle-treated (negative control; NC) cells was scarcely detected except for the membrane-bounded form. On the other hand, in GI9-treated cells, β-catenin accumulated in their nucleus in a dose dependent manner. These results suggested that GI9-treatment activates intrinsic β-catenin in human HSC/HPCs. Next, CD34+ HSC/HPCs were cultured for 7 days in a serum-free medium containing with cytokines (SCF, FL, TPO, IL-6 and sIL-6R) and also with 2μM, 10μM of GI9 or vehicle. After 7 days culture, total viable cells and CD34+ cells were expanded 31.6±4.6 and 17.9±3.8 fold in NC cells, respectively (n=3). However, GI9-treatment could not maintain a proportion of CD34+ cells compared with NC significantly caused the growth inhibition in a dose dependent manner. From the analysis of cumulative distribution of first cell division among the cells treated with GI9 or vehicle, GI9-treatment caused delayed cell cycling especially in fractionated immature CD34+CD38− cells. In addition, GSK-3 inhibition lost SCID repopulating cells (SRCs) as tested in the NOD/SCID mouse model (SRCs was calculated to be 1 in 8,452 NC cells vs. in 45,503 GI9-treated cells using limiting dilution methods). These results suggested that activation of intrinsic β-catenin followed GSK-3 inhibition suppressed self-renewal of immature hematopoietic cells via modulating its cell cycle kinetics. Next, as for the multipotency of HSC/HPCs after the culture, the distribution pattern of immunophenotype and the colony forming ability were evaluated. About 80% of expanded cells expressed myeloid marker, CD33 in our culture system, however, GI9-treatment perturbed myeloid differentiation of CD34+ HSC/HPCs but induced the differentiation toward to megakaryocyte and erythroid lineages. Furthermore, in methylcellulose assay, although expanded cells with GI9-treatment generated all types of progenitors, GI9-treatment was inferior significantly in terms of expansion rate of myeloid progenitor, CFU-GM and superior in formation of erythroid progenitor, BFU/CFU-E compared with NC (No. of CFU-GM/1000 cells 151±65.8 vs. 284±17.0, No. of BFU/CFU-E/1000 cells 132±18.5 vs. 32.7.±7.0, respectively) (p<0.05, n=3). Similarly, in murine model, GI9-treatment tended to convert differentiation potential of common myeloid progenitor (CMP) from granulocyte and macrophage progenitor (GMP) to megakaryocyte and erythroid progenitor (MEP). As for this mechanism, we found that activated β-catenin suppresses the transcriptional activity of C/EBPα, which is essential transcription factor for granulocyte development, while it promotes the function of GATA1, essential transcription factor for megakaryocyte and erythrocyte development during the differentiation of HSC/HPCs. In addition, β-catenin competitively impeded the interaction between C/EBPα and its transcriptional coactivator, CBP/p300 in coimmunoprecipitaion analysis. Together, these results indicated that intrinsic β-catenin was supposed to play an important role in self-renewal and multipotency of HSC/HPCs and control the balance of lineage commitment of HSC/HPCs for normal hematopoiesis, presumably by regulating the interaction with essential transcription factors.

scholarly journals A central role of glutamine in Chlamydia infection

2019 ◽  
Author(s):  
Karthika Rajeeve ◽  
Nadine Vollmuth ◽  
Sudha Janaki-Raman ◽  
Thomas Wulff ◽  
Maximilian Schmalhofer ◽  
...  
Keyword(s):  
Host Cell ◽  
Metabolic Reprogramming ◽  
Glutamine Metabolism ◽  
Chlamydia Infection ◽  
Developmental Cycle ◽  
Dependent Manner ◽  
Obligate Intracellular ◽  
A Cell ◽  
Obligate Intracellular Bacteria

AbstractObligate intracellular bacteria like Chlamydia trachomatis undergo a complex developmental cycle between infectious non-replicative (EBs) and non-infectious replicative (RBs) forms. EBs shortly after entering a host cell transform to RBs, a crucial process in infection, initiating chlamydial replication. As Chlamydia fail to replicate outside the host cell it is currently unknown how the transition from EBs to RBs is initiated. Here we show in a cell-free approach in axenic media that uptake of glutamine by the bacteria is critical to initiate EB-RB transition. These bacteria utilize glutamine to synthesize cell wall peptidoglycan which has recently been detected in the septa of replicating intracellular Chlamydia. The increased requirement for glutamine in infected cells is achieved by reprogramming the glutamine metabolism in a c-Myc-dependent manner. Glutamine was effectively taken up by the glutamine transporter SLC1A5 and metabolized via glutaminase. Interference with this metabolic reprogramming limited growth of Chlamydia. Intriguingly, Chlamydia failed to produce progeny in SLC1A5 knockout mice. Thus, we report on the central role of glutamine for the development of an obligate intracellular pathogenic bacterium and the reprogramming of host glutamine metabolism, which may provide a basis for innovative anti-infective strategies.

scholarly journals 4-Hydroxyphenylpyruvate Dioxygenase-Like Protein Promotes Pancreatic Cancer Cell Progression and Is Associated With Glutamine-Mediated Redox Balance

2021 ◽  
Vol 10 ◽  
Author(s):  
Xianglai Ye ◽  
Xiujuan Wei ◽  
Jing Liao ◽  
Peipei Chen ◽  
Xueyun Li ◽  
...  
Keyword(s):  
Redox Balance ◽  
Metabolic Reprogramming ◽  
Glutamine Metabolism ◽  
Ductal Adenocarcinoma ◽  
Intermembrane Space ◽  
Dependent Manner ◽  
Uncharacterized Protein ◽  
Cell Progression ◽  
Mitochondrial Intermembrane Space

Tumor cells develop a series of metabolic reprogramming mechanisms to meet the metabolic needs for tumor progression. As metabolic hubs in cells, mitochondria play a significant role in this process, including energy production, biosynthesis, and redox hemostasis. In this study, we show that 4-hydroxyphenylpyruvate dioxygenase-like protein (HPDL), a previously uncharacterized protein, is positively associated with the development of pancreatic ductal adenocarcinoma (PDAC) and disease prognosis. We found that overexpression of HPDL in PDAC cells promotes tumorigenesis in vitro, whereas knockdown of HPDL inhibits cell proliferation and colony formation. Mechanistically, we found that HPDL is a mitochondrial intermembrane space localized protein that positively regulates mitochondrial bioenergetic processes and adenosine triphosphate (ATP) generation in a glutamine dependent manner. Our results further reveal that HPDL protects cells from oxidative stress by reprogramming the metabolic profile of PDAC cells toward glutamine metabolism. In short, we conclude that HPDL promotes PDAC likely through its effects on glutamine metabolism and redox balance.

scholarly journals Identify AMPK-Mediated Autophagy and Oxphos As a Novel Metabolic Vulnerability for Targeted Therapy in Mantle Cell Lymphoma

Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 1506-1506
Author(s):  
Yixin Yao ◽  
Yang Liu ◽  
Hui Zhang ◽  
Angela Leeming ◽  
Joseph Mitchell McIntosh ◽  
...  
Keyword(s):  
Research Funding ◽  
Metabolic Flux ◽  
Metabolic Stress ◽  
Metabolic Reprogramming ◽  
Glutamine Metabolism ◽  
Flux Analysis ◽  
Mantle Cell ◽  
Advanced Stages ◽  
Cellular Apoptosis ◽  
Leukemic Phase

Introduction: Metabolic reprogramming promotes cancer cell growth, metastasis, and therapeutic resistance in a multitude of cancers. Mantle cell lymphoma (MCL) is a rare and aggressive hematopoietic malignancy that exhibits dramatic alterations in the cellular metabolism, especially in advanced stages and at the time of relapse. Unchecked pro-tumor growth signaling and multidrug therapy induce genomic instability and metabolic stress. To sustain tumor survival, MCL cancer cells upregulate multiple essential metabolic pathways that include mitochondria biogenesis, OXPHOS, glutaminolysis, cytoprotective autophagy, and fatty acid β-oxidation. While we recently have demonstrated that OXPHOS is upregulated and mediates resistance to ibrutinib, a Bruton's tyrosine kinase (BTK) inhibitor, in MCL, the underlying mechanism remains to be elucidated. Cytoprotective autophagy is known to be induced in chronic hypoxic microenvironments such as bone marrow and secondary lymphoid organs, and it in turn contributes to drug resistance and promotes MCL tumor survival. AMPK, a central regulator of cellular metabolism, is activated when MCL cells are challenged with metabolic stress. Consistently, AMPKα1 is highly activated in a subset of MCL at the leukemic phase. AMPK dependence and metabolic reprogramming represent vulnerabilities that could be potentially targeted for MCL treatment. Methods: Primary MCL biopsies, apheresis, or blood specimens, as well as MCL cell lines, were used for metabolic and functional analyses. Metabolomics profiling was carried out using Liquid Chromatography Mass Spectrometry (LC-MS). Mitochondrial membrane potential was determined by staining MCL cells with MitoStatus or TMRE and flow cytometry analysis. OCR (oxygen consumption rate) and ECAR (extracellular acidification rate) were determined by Seahorse metabolic flux analysis. Autophagy flux was monitored with tandem mRFP-EGFP-LC3 fluorescence reporter analysis. Other analyses included western blotting, real-time qPCR, and cell viability assay (Cell Titer-Glo). Pharmacological inhibitors were used for the down-modulation of ULK1, AMPK, autophagy, and OXPHOS. Results: Metabolomics profiling of steady-state levels of TCA metabolites showed significant increases in levels of α-KG, glutamate, malate, and fumarate, indicating upregulated glutaminolysis in subsets of MCL that are recurrent or refractory to targeted therapeutics including ibrutinib. Functional analysis illustrates that glutamine deprivation leads to reduced ATP and cell viability in a subset of MCL, while pharmacological inhibition of glutamine metabolism leads to reduced mitochondria membrane potential and increased cellular apoptosis. Seahorse metabolic flux analysis revealed enhanced OXPHOS activity in ibrutinib-resistant MCL cells as indicated by increased OCR. Inhibition of OXPHOS or glutamine metabolism impairs OCR and subsequently induces dose-dependent cellular apoptosis. Further, autophagy flux is increased in the same MCL cells with mRFP-EGFP-LC3 as a reporter. IHC and western blot analysis demonstrated that AMPKα1 is highly activated in a subset of MCL at the leukemic phase, concomitant with an increased NADP:NADPH and AMP:ATP ratio, indicating energy stress. AMPK activation promotes cytoprotective autophagy, and AMPK blockade suppresses autophagy, mitochondria biogenesis, and activity (OCR and ATP production), ultimately inhibiting MCL proliferation under metabolic stress. Conclusions: Our results demonstrate that AMPK activation promotes cytoprotective autophagy, glutaminolysis, and OXPHOS in established MCL, thus representing unique metabolic vulnerabilities that could be potentially targeted for MCL treatment. As AMPKα1 inhibitors are underexplored, it is critical to identify and develop more potent and specific inhibitors of the kinase and define the in vivo functions of its activation in certain advanced cancers. Similarly, pharmacological blockade of the dysregulated autophagy, glutaminolysis, and OXPHOS can be extensively exploited for treatment of MCL patients, especially those at advanced stages of the disease. Disclosures Wang: Janssen: Consultancy, Honoraria, Research Funding, Speakers Bureau; Pharmacyclics: Honoraria, Research Funding; AstraZeneca: Consultancy, Honoraria, Research Funding, Speakers Bureau; MoreHealth: Consultancy, Equity Ownership; Acerta Pharma: Consultancy, Research Funding; Kite Pharma: Consultancy, Research Funding; Guidepoint Global: Consultancy; BioInvent: Consultancy, Research Funding; VelosBio: Research Funding; Loxo Oncology: Research Funding; Celgene: Honoraria, Research Funding; Juno Therapeutics: Research Funding; Aviara: Research Funding; Dava Oncology: Honoraria.

High Altitude hypoxia

2020 ◽  
Vol 17 ◽  
Author(s):  
Asma Babar ◽  
Kifayatullah Mengal ◽  
Abdul Hanan Babar ◽  
Shixin Wu ◽  
Mujahid Ali Shah ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
High Altitude ◽  
Molecular Mechanisms ◽  
Strong Association ◽  
Haemoglobin Concentration ◽  
Metabolic Reprogramming ◽  
Molecular Networks ◽  
Whole Genome ◽  
Gene Expressions ◽  
Transcriptional Responses

: The world highest and largest altitude area is called the Qinghai-Tibetan plateau (QTB), which harbors unique animal and plant species. Mammals that inhabit the higher altitude regions have adapted well to the hypoxic conditions. One of the main stressors at high altitude is hypoxia. Metabolic responses to hypoxia play important roles in cell survival strategies and some diseases. However, the homeostatic alterations that equilibrate variations in the demand and supply of energy to maintain organismal function in a prolonged low O2 environment persist partly understood, making it problematic to differentiate adaptive from maladaptive responses in hypoxia. Tibetans and yaks are two perfect examples innate to the plateau for high altitude adaptation. By the scan of the whole-genome, EPAS1 and EGLN1 were identified as key genes associated with sustained haemoglobin concentration in high altitude mammals for adaptation. The yak is a much more ancient mammal which has existed on QTB longer than humans, it is, therefore, possible that natural selection represented a diverse group of genes/pathways in yaks. Physiological characteristics are extremely informative in revealing molecular networks associated with inherited adaptation, in addition to the whole-genome adaptive changes at the DNA sequence level. Gene-expression can be changed by a variety of signals originating from the environment, and hypoxia is the main factor amongst them. The hypoxia-inducible factors (HIF-1α and EPAS1/HIF-2α) are the main regulators of oxygen in homeostasis which play a role as maestro regulators of adaptation in hypoxic reaction of molecular mechanisms. (Vague) The basis of this review is to present recent information regarding the molecular mechanism involved in hypoxia that regulates candidate genes and proteins. Many transcriptional responses toward hypoxia are facilitated by HIFs that change the number of gene expressions and help in angiogenesis, erythropoiesis, metabolic reprogramming and metastasis. HIFs also activate several signals highlighting a strong association between hypoxia, the misfolded proteins’ accumulation in the endoplasmic reticulum in stress and activation of unfolded protein response (UPR). It was observed that at high-altitude, pregnancies yield a low birth weight ∼100 g per1000 m of the climb. (Vague) It may involve variation in the events of energy-demanding, like protein synthesis. Prolonged hypobaric hypoxia causes placental ER stress, which in turn, moderates protein synthesis and reduces proliferation. Further, Cardiac hypertrophy by cytosolic Ca2+ raises and Ca2+/calmodulin, calcineurin stimulation, NF-AT3 pathway might be caused by an imbalance in Sarcoplasmic reticulum ER Ca2, might be adaptive in beginning but severe later.

scholarly journals Matrix Stiffness Modulates Metabolic Interaction between Human Stromal and Breast Cancer Cells to Stimulate Epithelial Motility

Metabolites ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 432
Author(s):  
Iván Ponce ◽  
Nelson Garrido ◽  
Nicolás Tobar ◽  
Francisco Melo ◽  
Patricio C. Smith ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Cancer Cells ◽  
Cancer Progression ◽  
Stromal Cells ◽  
Glucose Transporter ◽  
Lactate Production ◽  
Resonance Energy ◽  
Metabolic Reprogramming ◽  
Dependent Manner ◽  
Functional Link

Breast tumors belong to the type of desmoplastic lesion in which a stiffer tissue structure is a determinant of breast cancer progression and constitutes a risk factor for breast cancer development. It has been proposed that cancer-associated stromal cells (responsible for this fibrotic phenomenon) are able to metabolize glucose via lactate production, which supports the catabolic metabolism of cancer cells. The aim of this work was to investigate the possible functional link between these two processes. To measure the effect of matrix rigidity on metabolic determinations, we used compliant elastic polyacrylamide gels as a substrate material, to which matrix molecules were covalently linked. We evaluated metabolite transport in stromal cells using two different FRET (Fluorescence Resonance Energy Transfer) nanosensors specific for glucose and lactate. Cell migration/invasion was evaluated using Transwell devices. We show that increased stiffness stimulates lactate production and glucose uptake by mammary fibroblasts. This response was correlated with the expression of stromal glucose transporter Glut1 and monocarboxylate transporters MCT4. Moreover, mammary stromal cells cultured on stiff matrices generated soluble factors that stimulated epithelial breast migration in a stiffness-dependent manner. Using a normal breast stromal cell line, we found that a stiffer extracellular matrix favors the acquisition mechanistical properties that promote metabolic reprograming and also constitute a stimulus for epithelial motility. This new knowledge will help us to better understand the complex relationship between fibrosis, metabolic reprogramming, and cancer malignancy.

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