Purine metabolism in human T lymphocytes: role of the purine nucleoside cycle

1984 ◽  
Vol 62 (7) ◽  
pp. 577-583 ◽  
Author(s):  
Amos Cohen ◽  
Jerzy Barankiewicz ◽  
Howard M. Lederman ◽  
Erwin W. Gelfand
Keyword(s):  
T Lymphocytes ◽  
Peripheral Blood ◽  
De Novo ◽  
S Phase ◽  
Purine Metabolism ◽  
Purine Nucleoside ◽  
Significant Activity ◽  
Purine Nucleotides ◽  
Biosynthetic Activity ◽  
Cycle Dependent

Human intrathymic T lymphocytes were separated by a bovine serum albumin density gradient into a population of G1-phase small thymocytes and a population of S-phase-enriched large thymocytes. Purine metabolism was studied in these thymocyte populations, representing immature T lymphocytes, and compared with the metabolism of mature T lymphocytes isolated from the peripheral blood. De novo purine biosynthesis was highly cell cycle dependent; i.e., de novo purine biosynthetic activity was found only in large S-phase thymocytes, whereas both G1 T-cell populations lacked any significant activity. Thus G1-phase small thymocytes and G1-phase peripheral blood T lymphocytes have only salvage pathways to maintain their purine nucleotide pools. Despite the similarity of purine salvage activities in G1 thymocytes and in peripheral blood T lymphocytes, small thymocytes have fourfold lower levels of purine nucleoside triphosphates. The decreased levels of purine nucleotides in G1 thymocytes may be the result of increased purine efflux. It was found that an unusually large proportion (24–48%) of hypoxanthine incorporated by G1 thymocytes is excreted into the medium in the form of inosine.

De Novo Synthesis of Purine Nucleotides in Human Peripheral Blood Platelets

1977 ◽  
Author(s):  
Z. Jerushalmy ◽  
M. Patya ◽  
O. Sperling
Keyword(s):  
Peripheral Blood ◽  
De Novo ◽  
Human Peripheral Blood ◽  
Blood Platelets ◽  
Calf Serum ◽  
De Novo Synthesis ◽  
Purine Nucleotides ◽  
Detectable Rate ◽  
Normal Human ◽  
Normal Human Peripheral Blood

Human blood platelets were gtudied for the presence of the pathway of de novo synthesis of purine nucleotides. 8 x 108 cells were incubated for 2.5 h at 37°C in 2 ml of Eagle’s Minimal Essential Medium containing Earle’s Balanced Salt Solution, 15% fetal calf serum and 20 μCi sodium [14C] formate (59 mCi/mmole). Platelets were found to incorporate 14C into total purines at a slow but detectable rate of 50–70 pmoles/8 x 108 cells/2.5 h. This incorporation was inhibited by approximately 80% at 10 mM azaserine and by 60% at 0.1 mM adenine. Adenine is known to affect the rate of purine synthesis de novo through the activity of phosphoribosylpyrophosphate amidotransferase, the first committed enzyme of this pathway. The results suggest the presence of the complete pathway of de novo synthesis of purine nucleotides in normal human peripheral blood platelets.

scholarly journals DRES-09. REGULATORY EFFECTS OF THE CILIARY GTPASE ARL13B ON PURINE METABOLISM IN GBM

2019 ◽  
Vol 21 (Supplement_6) ◽  
pp. vi73-vi73
Author(s):  
Miranda Saathoff ◽  
Jack Shireman ◽  
Eunus Ali ◽  
Cheol Park ◽  
Issam Ben-Sahra ◽  
...  
Keyword(s):  
Mammalian Cells ◽  
De Novo ◽  
Specific Activity ◽  
Purine Metabolism ◽  
P Value ◽  
Salvage Pathway ◽  
De Novo Synthesis ◽  
Dna Double Strand Breaks ◽  
Purine Nucleotides ◽  
Regulatory Effects

Abstract Glioblastoma (GBM) is the most common form of adult primary brain cancer. Despite an aggressive treatment regimen – surgical resection, irradiation, and temozolomide (TMZ) chemotherapy – patients’ prognosis is still grim. TMZ acts by methylating purines, specifically at the O6 and N7 positions of guanine, to induce cytotoxic DNA double-strand breaks. We thus wanted to explore how purine metabolism may contribute to TMZ-resistance. In mammalian cells, purine nucleotides can be recycled by the salvage pathway or generated via de novo synthesis. The salvage pathway is energetically inexpensive relative to de novo thus, highly proliferative GBM cells preferentially utilize the salvage pathway. We have shown that salvage synthesis is reduced in response to TMZ (p-value=0.0021), hinting that the cells may utilize de novo to evade therapy induced alkylation of purines. Using immunoprecipitation-mass spectroscopy analysis, we found a novel interaction between the ciliary GTPase ARL13B and IMPDH2, the rate-limiting enzyme in de novo synthesis. We have shown that this interaction, occurring at the C-terminal domain of ARL13B, plays a significant role in the regulation of purine biosynthesis as abolishing it through ARL13B knockdown reduced flux through de novo (p-value< 0.0001) synthesis as measured by the specific activity of IMPDH2. Further, the lentiviral-mediated rescue of ARL13B brings IMPDH2 activity back to basal levels (p< 0.0001). Given its canonical function as a GTPase, we hypothesize that ARL13B acts as a novel regulator of de novo synthesis by sequestering GDP, allowing IMPDH2 to sense and respond to the cytosolic levels of guanine nucleotides. Without ARL13B the de novo pathway is halted, forcing the cells to rely on salvage to replenish nucleotide pools. Reliance on this pathway in the presence of TMZ causes cells to incorporate damaged nucleotides as a result of the drug’s alkylating action leading to the increased therapeutic efficacy of TMZ.

scholarly journals Cell cycle-dependent regulation of mammalian ribonucleotide reductase. The S phase-correlated increase in subunit M2 is regulated by de novo protein synthesis.

1984 ◽  
Vol 259 (19) ◽  
pp. 11695-11700
Author(s):  
S Eriksson ◽  
A Gräslund ◽  
S Skog ◽  
L Thelander ◽  
B Tribukait
Keyword(s):  
Cell Cycle ◽  
Protein Synthesis ◽  
Ribonucleotide Reductase ◽  
De Novo ◽  
S Phase ◽  
Cycle Dependent ◽  
De Novo Protein Synthesis

Disorders of purine and pyrimidine metabolism

2020 ◽  
pp. 2015-2031
Author(s):  
Anthony M. Marinaki ◽  
Lynette D. Fairbanks ◽  
Richard W.E. Watts
Keyword(s):  
Uric Acid ◽  
De Novo ◽  
Purine Metabolism ◽  
Pyrimidine Metabolism ◽  
Purine Nucleotides ◽  
Inherited Disorders ◽  
Pyrimidine Nucleotides ◽  
Signal Transducers ◽  
Uric Acid Transporters ◽  
Inflammatory Drugs

Disorders of purine and pyrimidine metabolism are due to abnormalities in the biosynthesis, interconversion, and degradation of the purines—adenine and guanine—and of the pyrimidines—cytosine, thymine, and uracil. The purine nucleotides, their cyclic derivatives (cAMP and cGMP), and their more highly phosphorylated derivatives have functions in many aspects of intermediary metabolism. Purine compounds also function as signal transducers, neurotransmitters, vasodilators, and mediators of platelet aggregation. Disorders of purine metabolism—the end point of purine metabolism in humans is uric acid. When uric acid levels become supersaturated in body fluids, uric acid and sodium urate monohydrate crystallize, causing gout. This results from either overproduction or underexcretion of urate, or from a combination of these defects. Decreased net tubular urate secretion is most often due to genetic polymorphism in uric acid transporters and is the commonest cause of primary (‘idiopathic’) gout. Gout may be secondary to a wide variety of renal disorders. Gout is also a consequence of enzymatic defects that accelerate de novo purine synthesis. Acute attacks of gout are treated with nonsteroidal anti-inflammatory drugs, colchicine, or steroids. Hypouricaemia may be caused by inherited disorders of uric acid biosynthesis or may be due to inherited or acquired renal tubule transport defects. Disorders of pyrimidine metabolism—the de novo synthesis of pyrimidine nucleotides involves a series of six reactions beginning with the formation of carbamyl phosphate and concluding with orotidine monophosphate, which then undergoes a series of interconversion and salvage reactions. The inherited disorders of pyrimidine metabolism, which can present in a wide variety of ways, are much less common and/or much less easily recognized than disorders of purine metabolism.

Characterization of Monocyte-Associated Factor V

1993 ◽  
Vol 70 (02) ◽  
pp. 273-280 ◽  
Author(s):  
Janos Kappelmayer ◽  
Satya P Kunapuli ◽  
Edward G Wyshock ◽  
Robert W Colman
Keyword(s):  
Monoclonal Antibody ◽  
Light Chain ◽  
Peripheral Blood ◽  
De Novo ◽  
Factor V ◽  
Blood Monocytes ◽  
De Novo Synthesis ◽  
Hep G2 ◽  
Hep G2 Cells ◽  
Peripheral Blood Monocytes

SummaryWe demonstrate that in addition to possessing binding sites for intact factor V (FV), unstimulated peripheral blood monocytes also express activated factor V (FVa) on their surfaces. FVa was identified on the monocyte surface by monoclonal antibody B38 recognizing FVa light chain and by human oligoclonal antibodies H1 (to FVa light chain) and H2 (to FVa heavy chain) using immunofluorescence microscopy and flow cytometry. On Western blots, partially cleaved FV could be identified as a 220 kDa band in lysates of monocytes. In addition to surface expression of FVa, monocytes also contain intracellular FV as detected only after permeabilization by Triton X-100 by monoclonal antibody B10 directed specifically to the Cl domain not present in FVa. We sought to determine whether the presence of FV in peripheral blood monocytes is a result of de novo synthesis.Using in situ hybridization, no FV mRNA could be detected in monocytes, while in parallel control studies, factor V mRNA was detectable in Hep G2 cells and CD18 mRNA in monocytes. In addition, using reverse transcriptase and the polymerase chain reaction, no FV mRNA was detected in mononuclear cells or in U937 cells, but mRNA for factor V was present in Hep G2 cells using the same techniques. These data suggest that FV is present in human monocytes, presumably acquired by binding of plasma FV, and that the presence of this critical coagulation factor is not due to de novo synthesis.

Long-term effect of high cyclophosphamide doses on the repertoire of T-cell receptors of peripheral blood T-lymphocytes in patients with autoimmune vasculitis

2017 ◽  
pp. 68-74
Author(s):  
E. M. Merzlyak ◽  
◽  
S. A. Kasatskaya ◽  
A. V. Sosnovskaya ◽  
M. A. Israelson ◽  
...  
Keyword(s):  
T Cell ◽  
T Lymphocytes ◽  
T Cell Receptors ◽  
Peripheral Blood ◽  
Term Effect ◽  
Cell Receptors ◽  
Long Term Effect

Purine Nucleoside Phosphorylase (PNP) Deficiency Leading to Accumulation of Lymphocytes in S-Phase

1986 ◽  
Vol 3 (4) ◽  
pp. 353-359 ◽  
Author(s):  
Ger T. Rijkers ◽  
Ben J. M. Zegers ◽  
Leo J. M. Spaapen ◽  
Derk H. Rutgers ◽  
John J. Roord ◽  
...  
Keyword(s):  
Purine Nucleoside Phosphorylase ◽  
S Phase ◽  
Purine Nucleoside ◽  
Nucleoside Phosphorylase

scholarly journals Clinical observations of bone marrow transfusion for promoting bone marrow reconstruction after chemotherapy for AIDS-related lymphoma

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Yixuan Liu ◽  
Suhong Xie ◽  
Lei Li ◽  
Yanhui Si ◽  
Weiwei Zhang ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Immune System ◽  
T Lymphocytes ◽  
Peripheral Blood ◽  
Autologous Bone Marrow ◽  
Control Group ◽  
Peripheral Vein ◽  
Significant Difference ◽  
Autologous Bone ◽  
Aids Related Lymphoma

Abstract Background This study investigates the effect of autologous bone marrow transfusion (BMT) on the reconstruction of both bone marrow and the immune system in patients with AIDS-related lymphoma (ARL). Methods A total of 32 patients with ARL participated in this study. Among them, 16 participants were treated with conventional surgery and chemotherapy (control group) and the remaining 16 patients were treated with chemotherapy followed by autologous bone marrow transfusion via a mesenteric vein (8 patients, ABM-MVI group) or a peripheral vein (8 patients, ABM-PI group). Subsequently, peripheral blood and lymphocyte data subsets were detected and documented in all patients. Results Before chemotherapy, no significant difference in indicators was observed between three groups of ARL patients. Unexpectedly, 2 weeks after the end of 6 courses of chemotherapy, the ABM-MVI group, and the ABM-PI group yielded an increased level of CD8+T lymphocytes, white blood cells (WBC), and platelet (PLT) in peripheral blood in comparison to the control group. Notably, the number of CD4+T lymphocytes in the ABM-PI group was significantly higher than that in the other two groups. Additionally, no significant difference in haemoglobin levels was observed before and after chemotherapy in both the ABM-MVI and ABM-PI groups, while haemoglobin levels in the control group decreased significantly following chemotherapy. Conclusions Autologous bone marrow transfusion after chemotherapy can promote the reconstruction of both bone marrow and the immune system. There was no significant difference in bone marrow recovery and reconstruction between the mesenteric vein transfusion group and the peripheral vein transfusion group.

scholarly journals Rapamycin-induced inhibition of p34cdc2 kinase activation is associated with G1/S-phase growth arrest in T lymphocytes.

1993 ◽  
Vol 268 (5) ◽  
pp. 3734-3738
Author(s):  
W.G. Morice ◽  
G.J. Brunn ◽  
G. Wiederrecht ◽  
J.J. Siekierka ◽  
R.T. Abraham
Keyword(s):  
T Lymphocytes ◽  
Growth Arrest ◽  
S Phase ◽  
Phase Growth ◽  
Kinase Activation
Sign in / Sign up

Export Citation Format

Share Document