Guanine Nucleotide Metabolism in Red Blood Cells: The Metabolic Basis for GTP Depletion in HGPRT and PNP Deficiency

1989 ◽  
pp. 67-71 ◽  
Author(s):  
Y. Sidi ◽  
I. Gelvan ◽  
S. Brosh ◽  
J. Pinkhas ◽  
O. Sperling
Keyword(s):  
Red Blood Cells ◽  
Blood Cells ◽  
Nucleotide Metabolism ◽  
Guanine Nucleotide ◽  
Metabolic Basis

scholarly journals Transcriptional Regulation of Coenzyme Q Biosynthesis By TIF1γ Drives Erythropoiesis

Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 152-152
Author(s):  
Marlies P. Rossmann ◽  
Karen Hoi ◽  
Victoria Chan ◽  
Julie R. Perlin ◽  
Elliott J. Hagedorn ◽  
...  
Keyword(s):  
Red Blood Cells ◽  
Blood Cells ◽  
De Novo ◽  
Coenzyme Q ◽  
Transcription Elongation ◽  
Erythroid Differentiation ◽  
Nucleotide Metabolism ◽  
Mitochondrial Metabolism ◽  
Hematopoietic Stem ◽  
Equity Ownership

Understanding the cell-autonomous as well as niche contributions governing erythropoiesis is critical for directed differentiation approaches of hematopoietic stem cells into differentiated red blood cells (RBCs) to treat blood disorders such as anemias and leukemias. Transcriptional intermediary factor 1 gamma (TIF1γ) is essential for erythropoiesis from zebrafish to mammals. Zebrafish moonshine mutant embryos defective for tif1γ do not make red blood cells (RBCs) due to a transcription elongation block characterized by aberrantly paused RNA polymerase II. Loss of factors involved in transcription elongation control, PAF1 and spt5, rescues the moonshine RBC defect. To elucidate the TIF1γ-mediated mechanisms in erythroid differentiation, we have performed a high-content chemical suppressor screen in the bloodless moonshine mutant using 3,500 compounds. Among the suppressors, we identified leflunomide, an inhibitor of dihydroorotate dehydrogenase (DHODH), an essential enzyme for de novo pyrimidine synthesis. Leflunomide as well as the structurally unrelated DHODH inhibitor brequinar both rescue the formation of primitive erythroid cells in 61% (38/62) and 68% (50/74) of moonshine embryos, respectively. Blastula transplant experiments revealed that tif1γ, in addition to its cell-autonomous role, plays a role in the hematopoietic niche for RBC development. Through in-vivo metabolomics analyses we have identified nucleotide metabolism as the most significantly altered process in moonshine mutants, including elevated levels of uridine monophosphate and low levels of nicotinamide adenine dinucleotide (NAD+). Low NAD+ levels are accompanied by a reduced oxygen consumption rate in tif1γ-depleted embryos by Seahorse analysis. In support, genome-wide transcriptome analysis coupled with chromatin immunoprecipitation studies revealed genes encoding coenzyme Q (CoQ) metabolic enzymes as direct TIF1γ targets. DHODH is the only enzyme of the pyrimidine de novo synthesis pathway located on the inner mitochondrial membrane and its activity is coupled to that of the electron transport chain (ETC). Rotenone, a potent ETC complex I inhibitor reverses the rescue of the blood defect by DHODH inhibition in moonshine embryos. Since DHODH function is linked to mitochondrial oxidative phosphorylation via CoQ activity, we asked whether alterations in mitochondrial metabolism might be causal for the RBC defect in moonshine mutants. Indeed, treatment with the CoQ analog decylubiquinone results in rescue of βe3 globin expression in 26% (33/126) of moonshine embryos. These results demonstrate a tight coordination of nucleotide and mitochondrial metabolism as a key function of tif1γ-dependent transcription and reveal that TIF1γ activity regulates a metabolic program that drives cell fate decisions in the early blood lineage. Our work highlights the importance of the plasticity achieved by transcription regulatory processes such as transcription elongation for metabolic processes during lineage differentiation and could have therapeutic potential for blood diseases and consequences for erythroid differentiation protocols. Disclosures Zon: Fate Therapeutics: Equity Ownership; Scholar Rock: Equity Ownership; CAMP4: Equity Ownership.

scholarly journals Elevated intracellular Ca2+ reveals a functional membrane nucleotide pool in intact human red blood cells

2011 ◽  
Vol 138 (4) ◽  
pp. 381-391 ◽  
Author(s):  
Teresa Tiffert ◽  
Virgilio L. Lew
Keyword(s):  
Atpase Activity ◽  
Red Blood Cells ◽  
Blood Cells ◽  
High Performance ◽  
Enzyme System ◽  
Membrane Surface ◽  
Nucleotide Metabolism ◽  
Human Red Blood Cells ◽  
Cell Extracts ◽  
Functional Membrane

Elevated intracellular calcium generates rapid, profound, and irreversible changes in the nucleotide metabolism of human red blood cells (RBCs), triggered by the adenosine triphosphatase (ATPase) activity of the powerful plasma membrane calcium pump (PMCA). In the absence of glycolytic substrates, Ca2+-induced nucleotide changes are thought to be determined by the interaction between PMCA ATPase, adenylate kinase, and AMP-deaminase enzymes, but the extent to which this three-enzyme system can account for the Ca2+-induced effects has not been investigated in detail before. Such a study requires the formulation of a model incorporating the known kinetics of the three-enzyme system and a direct comparison between its predictions and precise measurements of the Ca2+-induced nucleotide changes, a precision not available from earlier studies. Using state-of-the-art high-performance liquid chromatography, we measured the changes in the RBC contents of ATP, ADP, AMP, and IMP during the first 35 min after ionophore-induced pump-saturating Ca2+ loads in the absence of glycolytic substrates. Comparison between measured and model-predicted changes revealed that for good fits it was necessary to assume mean ATPase Vmax values much higher than those ever measured by PMCA-mediated Ca2+ extrusion. These results suggest that the local nucleotide concentrations generated by ATPase activity at the inner membrane surface differed substantially from those measured in bulk cell extracts, supporting previous evidence for the existence of a submembrane microdomain with a distinct nucleotide metabolism.

Hemoglobin crystals of the red blood cells in the human renal cortex: electron microscopic observations of the renal lithiasis

1978 ◽  
Vol 36 (2) ◽  
pp. 480-481
Author(s):  
Kosuke Ueda ◽  
Hiroto Washida ◽  
Nakazo Watari
Keyword(s):  
Red Blood Cells ◽  
Blood Cells ◽  
Renal Cortex ◽  
Uranyl Acetate ◽  
Osmic Acid ◽  
Renal Lithiasis ◽  
Electron Microscopic ◽  
Hemoglobin C ◽  
First Case ◽  
Ultrathin Sections

IntroductionHemoglobin crystals in the red blood cells were electronmicroscopically reported by Fawcett in the cat myocardium. In the human, Lessin revealed crystal-containing cells in the periphral blood of hemoglobin C disease patients. We found the hemoglobin crystals and its agglutination in the erythrocytes in the renal cortex of the human renal lithiasis, and these patients had no hematological abnormalities or other diseases out of the renal lithiasis. Hemoglobin crystals in the human erythrocytes were confirmed to be the first case in the kidney.Material and MethodsTen cases of the human renal biopsies were performed on the operations of the seven pyelolithotomies and three ureterolithotomies. The each specimens were primarily fixed in cacodylate buffered 3. 0% glutaraldehyde and post fixed in osmic acid, dehydrated in graded concentrations of ethanol, and then embedded in Epon 812. Ultrathin sections, cut on LKB microtome, were doubly stained with uranyl acetate and lead citrate.

Densitometric Identification of Primitive Erythroblasts After Reaction With Diaminobenzidine

1973 ◽  
Vol 31 ◽  
pp. 328-329
Author(s):  
John A. Trotter
Keyword(s):  
Red Blood Cells ◽  
Analytical Method ◽  
Blood Cells ◽  
Guinea Pigs ◽  
Specific Protein ◽  
Visual Examination ◽  
Hemoglobin Synthesis ◽  
Peroxidatic Activity ◽  
Small Density

Hemoglobin is the specific protein of red blood cells. Those cells in which hemoglobin synthesis is initiated are the earliest cells that can presently be considered to be committed to erythropoiesis. In order to identify such early cells electron microscopically, we have made use of the peroxidatic activity of hemoglobin by reacting the marrow of erythropoietically stimulated guinea pigs with diaminobenzidine (DAB). The reaction product appeared as a diffuse and amorphous electron opacity throughout the cytoplasm of reactive cells. The detection of small density increases of such a diffuse nature required an analytical method more sensitive and reliable than the visual examination of micrographs. A procedure was therefore devised for the evaluation of micrographs (negatives) with a densitometer (Weston Photographic Analyzer).

Scanning electron microscopy of erythrophagocytosis by Entamoeba histolytica trophozoites

1992 ◽  
Vol 50 (1) ◽  
pp. 880-881
Author(s):  
Victor Tsutsumi ◽  
Adolfo Martinez-Palomo ◽  
Kyuichi Tanikawa
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Red Blood Cells ◽  
Entamoeba Histolytica ◽  
Causative Agent ◽  
Blood Cells ◽  
Protozoan Parasite ◽  
Complex Phenomenon ◽  
Great Capacity ◽  
Scanning Electron

The protozoan parasite Entamoeba histolytica is the causative agent of amebiasis in man. The trophozoite or motile form is a highly dynamic and pleomorphic cell with a great capacity to destroy tissues. Moreover, the parasite has the singular ability to phagocytize a variety of different live or death cells. Phagocytosis of red blood cells by E. histolytica trophozoites is a complex phenomenon related with amebic pathogenicity and nutrition.

Ultrastructural observations on the in vitro cytoadherence of Plasmodium falciparum infected red blood cells

1990 ◽  
Vol 48 (3) ◽  
pp. 914-915
Author(s):  
D.J.P. Ferguson ◽  
A.R. Berendt ◽  
J. Tansey ◽  
K. Marsh ◽  
C.I. Newbold
Keyword(s):  
Plasmodium Falciparum ◽  
Red Blood Cells ◽  
Blood Cells ◽  
Umbilical Vein ◽  
Cell Types ◽  
Amelanotic Melanoma ◽  
Cytoplasmic Process ◽  
Umbilical Vein Endothelial Cells

In human malaria, the most serious clinical manifestation is cerebral malaria (CM) due to infection with Plasmodium falciparum. The pathology of CM is thought to relate to the fact that red blood cells containing mature forms of the parasite (PRBC) cytoadhere or sequester to post capillary venules of various tissues including the brain. This in vivo phenomenon has been studied in vitro by examining the cytoadherence of PRBCs to various cell types and purified proteins. To date, three Ijiost receptor molecules have been identified; CD36, ICAM-1 and thrombospondin. The specific changes in the PRBC membrane which mediate cytoadherence are less well understood, but they include the sub-membranous deposition of electron-dense material resulting in surface deformations called knobs. Knobs were thought to be essential for cytoadherence, lput recent work has shown that certain knob-negative (K-) lines can cytoadhere. In the present study, we have used electron microscopy to re-examine the interactions between K+ PRBCs and both C32 amelanotic melanoma cells and human umbilical vein endothelial cells (HUVEC).We confirm previous data demonstrating that C32 cells possess numerous microvilli which adhere to the PRBC, mainly via the knobs (Fig. 1). In contrast, the HUVEC were relatively smooth and the PRBCs appeared partially flattened onto the cell surface (Fig. 2). Furthermore, many of the PRBCs exhibited an invagination of the limiting membrane in the attachment zone, often containing a cytoplasmic process from the endothelial cell (Fig. 2).

Phagocytosis of opsonized red blood cells by hepatocytes after gene transfer of chimeric Fc γR III Aα and γcDNA

2001 ◽  
Vol 120 (5) ◽  
pp. A356-A357
Author(s):  
M FURUKAWA ◽  
Y MAGAMI ◽  
D NAKAYAMA ◽  
F MORIYASU ◽  
J PARK ◽  
...  
Keyword(s):  
Gene Transfer ◽  
Red Blood Cells ◽  
Blood Cells

Pathological alterations of cation movements in red blood cells

1972 ◽  
Vol 129 (2) ◽  
pp. 320-332 ◽  
Author(s):  
J. C. Parker
Keyword(s):  
Red Blood Cells ◽  
Blood Cells
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