Fbxo7 promotes Cdk6 activity to inhibit PFKP and glycolysis in T cells.

Deregulated Fbxo7 expression is associated with many pathologies, including anaemia, male sterility, cancer, and Parkinson's disease, demonstrating its critical role in a variety of cell types. Although Fbxo7 is an F-box protein that recruits substrates for SCF-type E3 ubiquitin ligases, it also promotes the formation of cyclin D/Cdk6/p27 complexes in an E3-ligase independent fashion. We discovered PFKP, the major gatekeeper of glycolysis, in a screen for Fbxo7 substrates. PFKP has been previously shown to be a critical substrate of Cdk6 for the viability of T-ALL cells. We investigated the molecular relationships between Fbxo7, Cdk6 and PFKP, and the functional effect Fbxo7 has on T cell metabolism, viability, and activation. Fbxo7 promotes Cdk6-independent ubiquitination and Cdk6-dependent phosphorylation of PFKP. Importantly Fbxo7-deficient cells have reduced Cdk6 activity, and haematopoietic and lymphocytic cell lines show a significant dependency on Fbxo7. Compared to WT cells, CD4+ T cells with reduced Fbxo7 expression show increased glycolysis, despite lower cell viability and activation levels. Metabolomic studies of activated CD4+ T cells confirm increased glycolytic flux in Fbxo7-deficient cells, as well as altered nucleotide biosynthesis and arginine metabolism. We show Fbxo7 expression is glucose-responsive at the mRNA and protein level, and we propose Fbxo7 inhibits PFKP and glycolysis via its activation of Cdk6.

The Cell Body Space Occupied by the Nucleus During the Cell Differentiation in Human Lymphocytic, Granulocytic and Erythroid Cell Lineages

The present nuclear and cell body diameter measurements demonstrated size differences of the approximate cell space estimate occupied by the cell nucleus during the cell differentiation in lymphocytic, granulocytic and erythroid cell lineages. These lineages were used as convenient models because all differentiation steps were easily identified and accessible in diagnostic peripheral blood or bone marrow smears of blood donors (BDs), patients suffering from chronic lymphocytic leukemia (CLL), patients with chronic myeloid leukemia (CML) and refractory anemia (RA) of the myelodysplastic syndrome (MDS). The cell space occupied by the nucleus was constant and did not change during the cell differentiation in the lymphocytic cell lineages of BDs and CLL patients despite the decreased cell size. In contrary, the cell space occupied by the nucleus markedly decreased in differentiating cells of granulocytic and erythroid lineages of patients suffering from CML. In the erythroid cell lineage in patients with RA of MDS the small reduction of the cell space occupied by the nucleus during the differentiation was not significant. The measurements also indicated that in progenitor cells of all studied cell lineages nuclei occupied more than 70 % of the cell space. Thus, the nucleus-cytoplasmic morphological and functional equilibrium appeared to be characteristic for each differentiation step and each specific cell lineage.

Stages of development of bladder of rats in the early postnatal period

The actual problem of practical medicine is the treatment of diseases of the lower department of the urinary system and about 20% of this pathology accounts for the proportion of the bladder. A histological survey of the bladders of 64 rats was conducted. Quantitative analysis of the results of the morphometric study was carried out using methods of variation statistics using Excel and STATISTICA programs. The aim of the study was to determine the average thickness of their own plate, muscle membrane, the average number of blood vessels in the microcirculation bed per unit area, their diameter, the number of lymphocytic cells. It was found that during the early stage of postnatal ontogenesis (up to 90 days of life of rats), the following changes in the structure of the bladder are observed: an increase in the thickness of the tear and muscle of the wall of the bladder occurs; an increase in the mucous membrane of bladder cells of the immunomorphological complex (lymphocytes, macrophages, and lymphocytic cell clusters), changes in the quantitative aspect and in the diversity of the cellular composition; there is an increase in the number of blood vessels in the microcirculation bed. These changes occurred progressively, with maximum expressiveness in the period of 30 days of life and subsequent stabilization of indicators. Such indications may be associated with a change in the type of nutrition of the rat, since 14 to 21 days they have a transition from dairy to natural nutrition. In the future, it is planned to conduct an investigation of the effect of antigenic stimulation on the structure of the wall of the bladder.

The Cytotoxicity of Epsilon Toxin fromClostridium perfringenson Lymphocytes Is Mediated by MAL Protein Expression

ABSTRACTEpsilon toxin (Etx) fromClostridium perfringensis a pore-forming protein that crosses the blood-brain barrier, binds to myelin, and, hence, has been suggested to be a putative agent for the onset of multiple sclerosis, a demyelinating neuroinflammatory disease. Recently, myelin and lymphocyte (MAL) protein has been identified to be a key protein in the cytotoxic effect of Etx; however, the association of Etx with the immune system remains a central question. Here, we show that Etx selectively recognizes and kills only human cell lines expressing MAL protein through a direct Etx-MAL protein interaction. Experiments on lymphocytic cell lines revealed that MAL protein-expressing T cells, but not B cells, are sensitive to Etx and reveal that the toxin may be used as a molecular tool to distinguish subpopulations of lymphocytes. The overall results open the door to investigation of the role of Etx andClostridium perfringenson inflammatory and autoimmune diseases like multiple sclerosis.

A novel type of congenital hypochromic anemia associated with a nonsense mutation in the STEAP3/TSAP6 gene

STEAP3/TSAP6 encodes a ferrireductase that is involved in the acquisition of iron by developing erythroblasts and steap3/tsap6 null-mice display severe microcytic anemia. We report a family in which 3 siblings born to healthy parents display transfusion-dependent hypochromic anemia. A nonsense STEAP3/TSAP6 was identified in the siblings at the heterozygous state. This mutation was inherited from their father while no mutation was found in their mother. A large variability of expression was found between normal alleles in a control population, confirming a previous report that STEAP3/TSAPS6 is an expressed quantitative trait locus (e-QTL). Determination of the relative allele expression showed that the “normal” allele was expressed at a significantly higher level in the father than in the affected siblings relative to the shared mutated allele. The blood level of STEAP3/TSAP6 mRNA was severely reduced in the siblings, while both parents were in the lower range of normal controls. The STEAP3/TSAP6 protein was also reduced in lymphocytic cell lines from the patients. Collectively, our data support the hypothesis that STEAP3/TSAP6 deficiency leads to severe anemia in the affected siblings and results from the combination of a mutated allele inherited from their father and a weakly expressed allele inherited from their mother.

OSU-DY7, a Novel D-Tyrosinol Derivative, Mediates Cytotoxicity in Chronic Lymphocytic Leukemia and Lymphoblastic Lymphoma through p38 Mitogen-Activated Protein Kinase Pathway.

Abstract 3778 Poster Board III-714 Introduction Chronic lymphocytic leukemia (CLL) is a most common form of adult leukemia with minimal treatment options. Drug resistance and associated immune deregulation limit use of current therapies, thus warranting need for alternative therapy development. Our laboratories recently identified a novel D-tyrosinol-derived compound targeting p38 MAPK pathway, OSU-DY7 [(R)-2-amino-3-(4-heptyloxy-phenyl)-propan-1-ol]. Here we demonstrate the efficacy of OSU-DY7 for lymphocytic cell lines and primary B cells from CLL patients. Materials and Methods We tested the pre-clinical efficacy of OSU-DY7 in primary CLL B cells and B cell lines representing CLL (MEC-1), ALL (697), and lymphoblastic lymphoma (Raji and Ramos). Results The cytotoxicity of OSU-DY7 was both dose- and time-dependent. The IC50 of OSU-DY7 at 24 hrs for MEC-1, 697, Raji, Ramos and primary B-CLL cells were 2.40 μM, 10.39 μM, 6.04 μM, 3.75 μM and 3.58 μM respectively. OSU-DY7 induced activation of caspase-3 and poly (adenocine diphosphate-ribose) polymerase (PARP) cleavage. Pancaspase inhibitor Z-VAD-FMK partially rescued OSU-DY7-induced cytotoxicity in CLL B cells and cell lines. Interestingly, OSU-DY7 mediated-cytotoxicity was associated with increased phosphorylation of p38 MAPK and its downstream target protein MAPKAPK2 in both lymphocytic cell lines and primary B-CLL cells. Compared with control group, the ratio of p-p38MAPK (Thr180Tyr182) versus p38MAPK in Raji cells treated with 2 μM, 4 μM and 8 μM of OSU-DY7 increased 2.2, 4.7 and 11 fold respectively (p<0.0001). Similar increase in p38MAPK phosphorylation was also observed in six CLL patient samples after treatment with OSU-DY7 2 μM, 4 μM and 8 μM for 24 hours (p=0.0004). Moreover, SB202190, a specific p38 MAPK inhibitor, decreased MAPKAPK2 protein level with concomitant rescue of the cells from the OSU-DY7 mediated-cytotoxicity. Thus pretreatment of Raji and primary CLL B cells with SB202190 reduced the OSU-DY7 induced cytotoxicity by 36.7% and 24.3% respectively by 24hrs (Raji:p<0.0001; primary CLL B cells: p<0.005 ). Furthermore, SB202190 rescued OSU-DY7 down regulated survivin protein by ∼2 fold (p<0.0001, n=3) and mRNA levels by 2.4 fold (95% CI: 1.56∼3.84 fold, p=0.0026, n=3) in Raji cells indicating a role for p38MAPK dependent regulation of survivin by OSU-DY7. Conclusions This study provides an evidence for a role of OSU-DY7 in p38 MAPK dependent activation and survivin down regulation associated with apoptosis in lymphocytic cells, thus warranting further development of this novel agent for alternative therapy for lymphocytic malignancies. [This work was supported by D. Warren Brown Foundation and Leukemia and Lymphoma Society] Disclosures: No relevant conflicts of interest to declare.

Virological characterization of the hepatitis C virus JFH-1 strain in lymphocytic cell lines

While hepatocytes are the major site of hepatitis C virus (HCV) infection, a number of studies have suggested that HCV can replicate in lymphocytes. However, in vitro culture systems to investigate replication of HCV in lymphocytic cells are severely limited. Robust HCV culture systems have been established using the HCV JFH-1 strain and Huh-7 cells. To gain more insights into the tissue tropism of HCV, we investigated the infection, replication, internal ribosome entry site (IRES)-dependent translation and polyprotein processing of the HCV JFH-1 strain in nine lymphocytic cell lines. HCV JFH-1 failed to infect lymphocytes and replicate, but exhibited efficient polyprotein processing and IRES-dependent translation in lymphocytes as well as in Huh-7 cells. Our results suggest that lymphocytic cells can support HCV JFH-1 translation and polyprotein processing, but may lack some host factors essential for HCV JFH-1 infection and replication.