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Shin Aizawa

Publications and source records attributed to Shin Aizawa.

16 recordsLinked to original sources
PubMed2006

Role of polyamines derived from arginine in differentiation and proliferation of human blood cells.

L-Arginine is a precursor of polyamine, nitric oxide (NO), creatine, and agmatine and is essential for the differentiation and proliferation of blood cells, although the precise biological role of L-arginine is unclear. We have recently reported that the depletion of L-arginine in cultured medium prevented both proliferation and differentiation of blood cells (Shima et al., Blood First Edition Paper, October 6, 2005; DOI 10.1182). Since one of metabolic products of L-arginine in the cells is polyamine that associates with cell differentiation and proliferation, the effects of L-arginine on the human K562 cell line and human cord blood-derived CD34 positive cells were investigated by focusing on polyamines such as putrescine, spermidine, and spermine in the present study. When polyamines were added to the culture medium in the absence of L-arginine, the cells did not grow or differentiate well. However, when intracellular polyamines were depleted using ornithine decarboxylase inhibitor, alpha-difluoromethylornithine (DFMO), the proliferation and differentiation of K562 cells to erythrocytes were reduced even in the presence of L-arginine. Moreover, in the presence of DFMO, cell differentiation and proliferation were recovered by the addition of putrescine or spermidine in the presence of L-arginine. Accordingly, it was demonstrated that polyamines are essential for the proliferation and differentiation of the blood cells as the metabolites of L-arginine and the externally added polyamines are also effective by being taken up through polyamine transporter.

Antigens, CD34↗
PubMed2006

Effects of neopterin on the hematopoietic microenvironment of senescence-accelerated mice (SAM).

The pteridine neopterin (NP) is produced by monocytes and is known to be a useful marker of immunological activation, although, it remains elusive whether neopterin itself exhibits biological functions. Recently, we found that NP stimulates hematopoietic cell proliferation and differentiation by activating bone marrow stromal cell function. In order to elucidate the biological effect of NP on stromal cells, its effects on hematopoiesis was determined in the mouse model of age-related stromal impairment, senescence-accelerated mice (SAMs). An intraperitoneal administration of NP increased the number of peripheral leukocytes and CFU-GM in the bone marrow and spleen of young SAMs, however, no increase of CFU-GM in old SAMs (stromal impairment) was observed when compared with young SAMs. NP also increased the CFU-GM colony formation of bone marrow and spleen cells from young SAMs in a soft agar culture system, but it did not enhance CFU-GM colony formation of cells from old SAMs cultured in this system. Treatment with NP induced the production of hematopoietic stimulating factors, including IL-6 and GM-CSF, by bone marrow stromal cells from young SAMs but stromal cells from old SAMs did not respond to NP stimulation. Further studies will be required to clarify the mechanism by which NP stimulates the production of hematopoietic growth factors from stromal cells, the results of this study indicate that NP is a potent hematopoietic regulatory factor by activating stromal cell function(s).

Aging↗
PubMed2005

Analysis of changes in CD20, CD55, and CD59 expression on established rituximab-resistant B-lymphoma cell lines.

Rituximab has markedly improved treatment results for B-cell lymphoma, but there are resistance problems similar to those of other chemotherapy drugs. With regard to the acquisition of rituximab resistance, there have been several reports describing the relation between rituximab and complement regulatory factors or CD20, but many points remain unclear. To further investigate acquisition of resistance to rituximab-related complement-dependent cytotoxicity (CDC), we established rituximab-resistant B-lymphoma cell lines (RAMOS) in vitro and then analyzed expression of CD20, CD55, and CD59 on these resistant cells by flow cytometry. With repeated exposure to a low concentration of rituximab and complement, RAMOS cells gradually acquired rituximab resistance, and selection and increase of CD55(bright) and CD59(bright) cell populations due to rituximab-related CDC were observed. With repeated exposure to a high concentration of rituximab and complement, RAMOS cells promptly acquired rituximab resistance, and CD20 expression of RAMOS cells was decreased. Not only selection of CD20(dim) cells but also down-modulation of CD20 caused by rituximab-related CDC appeared to cause the decrease in CD20 expression. We believe our findings will prove to be useful for prevention of or release from rituximab resistance in cases of B-cell lymphoma.

Antibodies, Monoclonal↗
PubMed2005

L-arginine import via cationic amino acid transporter CAT1 is essential for both differentiation and proliferation of erythrocytes.

In the present study, we examined the role in hematopoiesis of cationic amino acid transporter 1 (CAT1), which transports L-arginine, L-lysine, L-ornithine, and L-histidine. The expression level of human CAT1 (hCAT1) mRNA in mononuclear cells (MNCs) fractionated according to lineage-selective markers was examined by reverse transcriptase-polymerase chain reaction. The expression of CAT1 in glycophorin A-positive erythroid cells was 8 times higher than in nonfractionated MNC (control) cells. Characteristics of L-arginine uptake by K562 cells, an established leukemic cell line used as an erythroid model, were similar to those of CAT1 in regards to saturation kinetics, sodium independence, and substantial inhibition of L-arginine uptake by N-ethylmaleimide, which is a specific inhibitor of system y+ amino acid transporter. Removal of L-arginine from the culture medium prevented both proliferation and differentiation of K562 cells, while removal of L-lysine or L-histidine had little effect on differentiation, though proliferation was blocked. Hematopoietic stem cells obtained from human cord blood failed to develop into erythroid cells in the absence of L-arginine in the culture medium. These findings indicate that hCAT1 is involved in erythroid hematopoiesis through its role in importing L-arginine, which appears to be essential for the differentiation of red blood cells.

Arginine↗
PubMed2005

Ineffective erythropoiesis in mutant mice with deficient pyruvate kinase activity.

OBJECTIVE: A deficiency of pyruvate kinase (PK) is the most common cause of hereditary nonspherocytic anemia due to glycolytic enzyme defects. Red cells are poorly deformable due to adenosine triphosphate depletion in individuals with a PK deficiency and are destroyed in the microcirculation of the reticuloendothelial system, leading to extravascular hemolysis. The pathophysiology of PK deficiency has been widely studied in PK-deficient mice (PK-1(slc)). We examined the effects of a PK deficiency on erythroid progenitor maturation using these mice. MATERIALS AND METHODS: The appearance of apoptotic cells in spleen of PK-1(slc) mice was examined by terminal deoxynucleotidyl-transferase-mediated dUTP nick-end labeling (TUNEL) staining. We also assayed hematopoietic stem cell colony formation in vitro in the spleen of PK-1(slc) mice, to investigate erythropoiesis, and annexin V binding, as a measure of apoptotic cells in constitutive erythroid colonies, to evaluate the maturation of erythroid progenitors. RESULTS: The number of hematopoietic progenitors including colony-forming unit erythroids, burst-forming unit erythroids (BFU-E), colony-forming unit granulocyte-macrophages, and multilineage colony-forming units in the spleens of PK-1(slc) was remarkably increased indicating hematopoiesis, and enhanced erythropoiesis in particular. TUNEL assays identified apoptotic cells in the splenic red pulp of the PK-1(slc) mice. Two-color flow cytometry detected apoptotic cells among anti-TER119-positive cells, suggesting that apoptotic cells were of erythroid lineage. Cells undergoing apoptosis were detected in cultures of BFU-E generated from bone marrow cells of PK-1(slc) mice. CONCLUSIONS: The results in this study indicate that the metabolic disturbance in PK deficiency alters not only the survival of red cells but also the maturation of erythroid progenitors, resulting in ineffective erythropoiesis.

Animals↗
PubMed2005

Cyclic polylactate inhibited growth of cloned leukemic cells through reducing glycolytic enzyme activities.

A novel supramolecular oligomer, cyclic polylactate (CPL) that was originally discovered in the culture medium of HeLa-S tumor cells, reportedly inhibits the growth of FM3A ascites tumor cells by inhibiting enzymes involved in the glycolytic pathway. We synthesized CPL containing 3- to 13-mers by prolonged heating and rapidly mixing a carbohydrate compound of the L-lactic acid monomer (C(3)H(6)O(3)) under decreased pressure, and studied its effects on the growth of the cloned leukemic cell, TF-1. CPL inhibited the growth of TF-1 cells and induced 7A6 antigen, which is expressed by cells undergoing apoptosis, on the surface of TF-1 cells. In addition, caspase 3, 8 and 9 activities of TF-1 cells were increased after exposure to CPL, indicating that CPL induces apoptotic changes in TF-1. Among the 6 glycolytic enzymes examined in this study, the activities of PFK and HK, induced by CPL, decreased. Interestingly, CPL was detected in conditioned medium of the stromal cell line, LS801, obtained from human bone marrow. This conditioned medium inhibited the growth of TF-1 cells, and induced the expression of 7A6 antigen. These findings suggest that CPL will be a useful chemotherapeutic agent against leukemia.

Bone Marrow Cells↗
PubMed2004

Expression of organic cation transporter OCTN1 in hematopoietic cells during erythroid differentiation.

OBJECTIVE: Organic cation/carnitine transporter, OCTN1 (SLC22A4) shows a relatively broad tissue distribution and transports organic cations in a pH-dependent manner. However, its physiological role remains to be clarified. To understand the physiological role of OCTN1, tissue expression of OCTN1 in human and mice was characterized. METHODS: Expression of OCTN1 in various tissues and blood cells was examined by reverse transcription-polymerase chain reaction (RT-PCR), Western blot, and flow cytometry analysis. RESULTS: Mouse OCTN1 mRNA was detected in kidney, smooth muscle, and hematopoietic tissues, such as spleen and bone marrow, by RT-PCR analysis. Further study focused on expression of OCTN1 in various types of blood cells. OCTN1 mRNA was detected in myeloid cells in mouse bone marrow, but not in lymphoid cells. Bone marrow nuclear cells positive for TER119, an erythrocyte marker, showed strong expression of OCTN1. Similarly, OCTN1 was strongly expressed in glycophorin A-positive erythroid cells obtained from human cord blood. In Western blot analysis, OCTN1 protein was detected in isolated mouse mature peripheral erythrocytes. Further analysis by RT-PCR and flow cytometry showed OCTN1 was expressed in both glycophorin A-positive and negative erythroid cells after cultivation. These findings suggested that OCTN1 transports compound(s) that are required for erythroid differentiation, maturation, and/or growth. CONCLUSION: The present study demonstrated that OCTN1 is associated with myeloid cells rather than lymphoid cells, and especially with erythroid-lineage cells at the transition stage from immature erythroid cells to peripheral mature erythrocytes.

Animals↗
PubMed2004

Senescent B lymphopoiesis is balanced in suppressive homeostasis: decrease in interleukin-7 and transforming growth factor-beta levels in stromal cells of senescence-accelerated mice.

The suppression of the B cell population during senescence has been considered to be due to the suppression of interleukin-7 (IL-7) production and responsiveness to IL-7; however, the upregulation of transforming growth factor-beta (TGF-beta) was found to contribute to B cell suppression. To investigate the mechanism of this suppression based on the interrelationship between IL-7 and TGF-beta during senescence, senescence-accelerated mice (SAMs), the mouse model of aging, were used in this study to elucidate the mechanisms of B lymphopoietic suppression during aging. Similar to regular senescent mice, SAMs showed a decrease in the number of IL-7-responding B cell progenitors (i.e., colony-forming unit pre-B [CFU-pre-B] cells in the femoral bone marrow [BM]). A co-culture system of B lymphocytes and stromal cells that the authors established showed a significantly lower number of CFU-pre-B cells harvested when BM cells were co-cultured with senescent stromal cells than when they were co-cultured with young stromal cells. Interestingly, cells harvested from a senescent stroma and those from the control culture without stromal cells were higher in number than those harvested from a young stroma, thereby implying that an altered senescent stromal cell is unable to maintain self-renewal of the stem cell compartment. Because TGF-beta is supposed to suppress the proliferative capacity of pro-B/pre-B cells, we added a neutralizing anti-TGF-beta antibody to the co-culture system with a pro-B/pre-B cell-rich population to determine whether such suppression may be rescued. However, unexpectedly, any rescue was not observed and the number of CFU-pre-B cells remained unchanged when BM cells were co-cultured with senescent stromal cells compared with the co-culture with young stromal cells, which essentially showed an increase in the number of CFU-pre-B cells (P < 0.001 in 5 microg/ml). Furthermore, TGF-beta protein level in the supernatant of cultured senescent stroma cells was evaluated by enzyme-linked immunoabsorbent assay, but surprisingly, it was found that TGF-beta concentration was significantly lower than that of cultured young stromal cells. Thus, TGF-beta activity was assumed to decline particularly in a senescent stroma, which means a distinct difference between the senescent suppression of B lymphopoiesis and secondary B lymphocytopenia. Concerning proliferative signaling, on the other hand, the level of IL-7 gene expression in cells from freshly isolated BM decreased significantly with age. Therefore, the acceleration of proliferative signaling and the deceleration of suppressive signaling may both be altered and weakened in a senescent stroma (i.e., homeosuppression).

Animals↗
PubMed2004

[A case of median nerve descended on the surface of the pronator teres muscle].

We report a case in which the left median nerve passed downwards on the surface of the pronator teres muscle in a 70-year-old male cadaver examined during student dissection practice in 2001 at Nihon University School of Medicine. In the present case, the lateral cord of the median nerve is formed of only the middle trunk, C7 and did not include upper trunk, C5, 6. The upper trunk continued the musculocutaneous nerve, but it did not participate in the median nerve. In the cubital fossa, the median nerve descended on the surface of the pronator teres muscle. The pronator teres muscle had an additional head which arose from the medial intermuscular septum. The brachial artery passed between the humeral head and the additional head. It suggested the relevance that the first branch from the median nerve to the forearm flexor muscle group is the union covered with the common ensheathing epineurium. It consisted of the pronator teres muscle branch, the flexor carpi radialis muscle branch, and the branch to the proximal belly of the muscle bundle of the flexor digitorum superficialis muscle (FDS) for the second digit (II-p), which also supplies the palmaris longus muscle. The branch to the FDS for the third to the fifth digit and the anterior interosseous nerve branch arose from the back of the median nerve following the first branch, and the two branches connected mutually. And the median nerve had a branch to the distal belly of the muscle bundle of the FDS for the second digit (II-d) in its more distal part.

Aged↗
PubMed2004

Identification of differentiation-inducing activity produced by human bone marrow stromal cell line LP101.

We have previously reported that human promyelocytic leukemia HL-60 cells can be induced to differentiate into mature granulocytes when HL-60 co-cultivated with human bone marrow stromal LP101 cells. In the present study, we investigated which factors produced by LP101 cells induce HL-60 cells to differentiate into mature granulocytes. The expression of the cell surface antigen CD11b on HL-60 cells was increased after a 72-h culture with the conditioned medium (CM) obtained from LP101 cells. LP101 cells were observed to produce various cytokines, including TNF-alpha, GM-CSF and IL-6. The neutralizing antibodies against these cytokines partially suppressed the CM-induced differentiation of HL-60 cells. Recombinant TNF-alpha induced the differentiation of HL-60 cells, and GM-CSF and IL-6 additionally enhanced the effect of TNF-alpha. When the CM was divided into a low molecular weight (LMW) fraction and a high molecular weight (HMW) fraction by ultrafiltration, the LMW fraction synergistically enhanced the differentiation inducible activity of TNF-alpha. These results demonstrate that LP101 cells induce the differentiation of HL-60 cells by producing various cytokines including TNF-alpha, IL-6, and GM-CSF, and that unknown low molecular weight factors also participate.

Antibodies↗
PubMed2003

Ineffective erythropoiesis in the spleen of a patient with pyruvate kinase deficiency.

In this study, possible adverse effects of pyruvate kinase (PK) deficiency on the maturation of erythroid progenitors were investigated. A 4-year-old Japanese girl with severe PK deficiency underwent splenectomy to reduce her need for blood transfusions. The spleen was examined a histologically, and the hematopoietic progenitors in the spleen were assayed to evaluate the extramedullary hematopoiesis of this PK-deficient subject. The number of hematopoietic progenitors including CFU-GM, BFU-E and CFU-GEMM in the spleen of the PK-deficient patient was much higher than those found in control spleens, indicating enhanced extramedullary hematopoiesis. TUNEL assay demonstrated apoptotic cells in the splenic red pulp of the PK-deficient patient. The expression of 7A6 antigen was detected in cells isolated from spleen and in cells cultured in vitro, but only in those cells that were positive for glycophorin A. These results provide evidence that the metabolic disturbances in PK deficiency affect not only the survival of red cells but also the maturation of erythroid progenitors, which results in premature cell death, i.e., apoptosis.

Apoptosis↗
PubMed2003

Requirement of soluble factors produced by bone marrow stromal cells on the growth of novel established human myeloma cell line.

The growth of myeloma cells is believed to be mediated by functional interactions between tumor cells and the marrow environment involving the action of several cytokines. We report on the establishment and characterization of a new human myeloma cell line (TAB1) that can be long-term maintained in the presence of conditioned medium of bone marrow stromal cells (BMCM) and a BMCM independent variant, C2-2. Both cell lines have plasma cell morphology and express plasma cell antigens (CD38, PCA-1 and immunoglobulin kappa light chain). In the absence of BMCM, TAB1 cells undergoing apoptosis were observed. Among the adherent molecules tested, these cells expressed VLA-4, ICAM-1 and H-CAM, but not VLA-5, suggesting that these were mostly immature plasmacytes. Introduction with exogenous IL-6 and/or GM-CSF, which were detected in BMCM, partially supported the proliferation of TAB1 cells. Treatment with anti-IL-6 antibody partially inhibited the proliferation of TAB1 cells cultured with BMCM. These findings strongly suggest that TAB1 required at least two or more factors on their growth in vitro; IL-6 was one of the factors necessary for cell growth. Further studies are required to clarify the precise molecules which support TAB1 cell growth in combination with IL-6, however, TAB1 and its variant C2-2 cells may offer an attractive model to unravel novel molecular mechanisms involved in bone marrow stroma-dependent growth of myeloma cells.

Adult↗
PubMed2002

Spatial redox regulation of a critical cysteine residue of NF-kappa B in vivo.

Reduction-oxidation (redox) regulation has been implicated in the activation of the transcription factor NF-kappaB. However, the significance and mechanism of the redox regulation remain elusive, mainly due to the technical limitations caused by rapid proton transfer in redox reactions and by the presence of many redox molecules within cells. Here we establish versatile methods for measuring redox states of proteins and their individual cysteine residues in vitro and in vivo, involving thiol-modifying reagents and LC-MS analysis. Using these methods, we demonstrate that the redox state of NF-kappaB is spatially regulated by its subcellular localization. While the p65 subunit and most cysteine residues of the p50 subunit are reduced similarly in the cytoplasm and in the nucleus, Cys-62 of p50 is highly oxidized in the cytoplasm and strongly reduced in the nucleus. The reduced form of Cys-62 is essential for the DNA binding activity of NF-kappaB. Several lines of evidence suggest that the redox factor Ref-1 is involved in Cys-62 reduction in the nucleus. We propose that the Ref-1-dependent reduction of p50 in the nucleus is a necessary step for NF-kappaB activation. This study also provides the first example of a drug that inhibits the redox reaction between two specific proteins.

Cysteine↗
PubMed2002

Formation of lymph follicles and germinal centers in the somatic and mesenteric lymph nodes of growing mice during ontogenesis.

We investigated the age-dependent changes that occur in the numbers of lymph follicles and germinal centers in various lymph nodes in BALB/C and ICR mice aged between four days and 16 to 18 weeks. Young adult BALB/C mice have a relatively small body size, compared to ICR mice at the same stage, where there is a relatively large body size. In BALB/C mice somatic (popliteal, brachial, axillary, inguinal, submandibular and deep cervical) and mesenteric lymph nodes were examined. In ICR mice only the somatic (popliteal, brachial and axillary) lymph nodes were examined. In both BALB/C and ICR mice, the primary follicles were apparent in most somatic nodes by the 6th postnatal day. Up to 28 days of age, the number of follicles per node increased, reaching different levels in nodes from different locations. Thereafter, in most of the somatic nodes in BALB/C mice the number of follicles increased only slightly, although there was a substantial increase in ICR mice, reaching a peak or a plateau at 8 or 12 weeks of age. In the mesenteric (ileocecal) nodes in BALB/C mice, the primary follicles first appeared at 10 to 12 days, then there was a linear increase until a plateau level was reached at 8 weeks of age. Germinal centers appeared in the mesenteric nodes at 28 days and increased rapidly in number thereafter. In most somatic nodes germinal centers were scarcely observable until 8 weeks of age. Based on our observations we have three suggestions. Firstly, in BALB/C mice there were two different patterns of age-dependent changes in the numbers of lymph follicles in the somatic and the mesenteric nodes during ontogenesis. These different patterns are probably due to variations in the magnitude of the exogenous antigen stimulatory effect. Secondly, it seems likely that the variations in the numbers of lymph follicles that are produced in somatic nodes at different locations during the first 28 days after birth relate to the dimensions of the body regions that are drained by that particular somatic node at that stage of development. Thirdly, in the relatively small BALB/C mice, the ontogenetic production of lymph follicles in a somatic node is mostly completed during the first four weeks of life, whereas in the relatively larger ICR mice, this process may continue until the young adult stage of 8 weeks.

Age Factors↗