Kazuko Ino

A potential activity of valproic acid in the stimulation of interleukin-3 mediated megakaryopoiesis and erythropoiesis

OBJECTIVE Although the anticancer activities of histone deacetylase (HDAC) inhibitors have been studied, a role for HDAC in normal hematopoiesis has not been clearly defined. Previous studies have shown that the potent HDAC inhibitor FK228 stimulates interleukin (IL)-3-mediated erythropoiesis. Here, we examined whether the widely used valproic acid (VPA) affects megakaryopoiesis as well as erythropoiesis. MATERIALS AND METHODS CD34(+) cells were incubated in serum-free or serum-containing cultures with cytokines, with or without VPA. RESULTS In the serum-free cultures containing IL-3+stem cell factor (SCF), VPA significantly increased generation of CD61(+)GPA(-) megakaryocytic and a CD61(+)GPA(+) mixture of megakaryocytic and erythroid precursors from CD34(+) hematopoietic precursors at a pharmacological concentration (100 microg/mL). The increase in generation of megakaryocytic and erythroid precursors by VPA was confirmed by replating cultured cells with thrombopoietin+SCF and erythropoietin+SCF, respectively. VPA was as potent as FK228. In cultures with granulocyte-macrophage colony-stimulating factor+SCF, where CD61(-)GPA(+) erythroid precursors were mostly developed, VPA mainly enhanced the generation of CD61(-)GPA(+) erythroid precursors. In serum-containing cultures, only low numbers of CD61(+) or GPA(+) cells were developed with IL-3+SCF. Nevertheless, a substantial number of these cells were generated with VPA. Furthermore, these stimulating effects of VPA were observed by incubating CD34(+) cells from patients with myelodysplastic syndrome. Quantitative reverse transcription polymerase chain reaction showed that VPA enhanced GATA-2, but not GATA-1, messenger RNA expression with IL-3+SCF. CONCLUSIONS These results indicate a novel role for VPA in enhancing the potential of IL-3 to stimulate megakaryopoiesis as well as erythropoiesis and suggest a new therapeutic approach of epigenetic therapy for hematological disease.

IKAROS isoform 6 enhances BCR-ABL1-mediated proliferation of human CD34+ hematopoietic cells on stromal cells.

The BCR-ABL1 induces chronic myelogenous leukemia (CML) and Ph+ acute lymphoblastic leukemia (ALL). Recent studies revealed high ratios of loss of the IKZF1 gene which encodes IKAROS in BCR-ABL1+ ALL and lymphoblastic crisis (LBC) of CML. However, little is known about the cooperativity between the aberrant IKAROS and BCR-ABL1 in primary human hematopoietic cells. We investigated the effects of expression of BCR-ABL1 and/or IK6, a natural dominant negative isoform of IKAROS, on proliferation and differentiation of human CD34+ cord blood cells with or without human bone marrow-derived stromal cells which support early B cell differentiation. Cell proliferation was remarkably enhanced by co-expression of BCR-ABL1 and IK6, with reduced expression of glycophorin A and increased expression of CD41, especially on stromal cells, compared with expression of BCR-ABL1 alone that resulted in expansion of erythroid progenitors. Interestingly, p190BCR-ABL1 showed higher dependency on stromal cells to stimulate cell growth with IK6, than p210BCR-ABL1. Furthermore, the cooperation was found to depend on direct cell adhesive interaction of hematopoietic progenitors with stromal cells. These findings suggest that IK6 and BCR-ABL1 synergistically contribute to leukemogenesis in human bone marrow stromal microenvironment, and may provide a clue to elucidate the mechanisms of leukemogenesis of Ph+ ALL and CML-LBC.

Human bone marrow stromal cells simultaneously support B and T/NK lineage development from human haematopoietic progenitors: a principal role for flt3 ligand in lymphopoiesis

The regulation of human early lymphopoiesis remains unclear. B‐ and T‐lineage cells cannot develop simultaneously with conventional stromal cultures. Here we show that telomerized human bone marrow stromal cells supported simultaneous generation of CD19+CD34lo/−CD10+cyCD79a+CD20+/−VpreB− pro‐B cells and CD7+CD34+ CD45RA+CD56−cyCD3− early T/Natural Killer (NK) cell precursors from human haematopoietic progenitors, and the generation of both lymphoid precursors was promoted by flt3 ligand (flt3L). On the other hand, stem cell factor or thrombopoietin had little or no effect when used alone. However, both acted synergistically with flt3L to augment the generation of both lymphoid precursors. Characteristics of these lymphoid precursors were evaluated by gene expression profiles, rearrangements of IgH genes, or replating assays. Similar findings were observed with primary human bone marrow stromal cells. Notably, these two lymphoid‐lineage precursors were generated without direct contact with stromal cells, indicating that early B and T/NK development can occur, at least in part, by stromal cell‐derived humoral factors. In serum‐free cultures, flt3L elicited similar effects and appeared particularly important for B cell development. The findings of this study identified the potential of human bone marrow stromal cells to support human early B and T lymphopoiesis and a principal role for flt3L during early lymphopoiesis.

Breakthrough cryptococcosis in a patient with systemic lupus erythematosus (SLE) receiving micafungin

A 67-year-old woman with systemic lupus erythematosus (SLE) was admitted to our hospital because of lupus nephritis. Methylprednisolone minipulse therapy dramatically reduced her proteinuria; however; she then complained of general fatigue with low-grade fever. Radiological and culture studies revealed no infectious focus, but she was treated with meropenem and micafungin, considering her immunosuppressive state. Cytomegalovirus antigenemia was later determined and ganciclovir was added. She became afebrile, but complained of nausea and headache, and disorientation, without meningeal signs. Because a brain computed tomography (CT) scan showed no abnormality, we initially suspected some kind of drug interaction. Despite the discontinuation of all drugs, however, she still suffered from disturbance of consciousness. A lumbar puncture revealed yeast cells stained by India ink. A diagnosis of cryptococcal meningitis was confirmed. Though fluconazole and meropenem were administered, the patient died. Autopsy findings revealed disseminated cryptococcosis concomitant with pulmonary aspergillosis. Micafungin is a recently approved echinocandin-class antifungal agent that is now widely used in Japan because of its minimal toxicity and broadspectrum activity. However, such echinocandins have limited activity against a number of fungi. Indeed, breakthrough trichosporonosis is becoming a significant problem in patients with hematological malignancies who are receiving echinocandins. To the best of our knowledge, breakthrough cryptococcosis, as seen in our patient, has not been reported previously in patients who were receiving micafungin as an empiric antifungal therapy. This case highlights that cryptococcosis should be kept in mind as a possible breakthrough infection during the administration of echinocandins, especially in patients with cellular immunodeficiency.

Monocytes infiltrate the pancreas via the MCP-1/CCR2 pathway and differentiate into stellate cells.

Recent studies have shown that monocytes possess pluripotent plasticity. We previously reported that monocytes could differentiate into hepatic stellate cells. Although stellate cells are also present in the pancreas, their origin remains unclear. An accumulation of enhanced green fluorescent protein (EGFP)+CD45– cells was observed in the pancreases and livers of chimeric mice, which were transplanted with a single hematopoietic stem cell isolated from EGFP-transgenic mice and treated with carbon tetrachloride (CCl4). Because the vast majority of EGFP+CD45– cells in the pancreas expressed stellate cell-associated antigens such as vimentin, desmin, glial fibrillary acidic protein, procollagen-I, and α-smooth muscle actin, they were characterized as pancreatic stellate cells (PaSCs). EGFP+ PaSCs were also observed in CCl4-treated mice adoptively transferred with monocytes but not with other cell lineages isolated from EGFP-transgenic mice. The expression of monocyte chemoattractant protein-1 (MCP-1) and angiotensin II (Ang II) increased in the pancreas of CCl4-treated mice and their respective receptors, C-C chemokine receptor 2 (CCR2) and Ang II type 1 receptor (AT1R), were expressed on Ly6Chigh monocytes isolated from EGFP-transgenic mice. We examined the effect of an AT1R antagonist, irbesartan, which is also a CCR2 antagonist, on the migration of monocytes into the pancreas. Monocytes migrated toward MCP-1 but not Ang II in vitro. Irbesartan inhibited not only their in vitro chemotaxis but also in vivo migration of adoptively transferred monocytes from peripheral blood into the pancreas. Irbesartan treatment significantly reduced the numbers of EGFP+F4/80+CCR2+ monocytic cells and EGFP+ PaSCs in the pancreas of CCl4-treated chimeric mice receiving EGFP+ bone marrow cells. A specific CCR2 antagonist RS504393 inhibited the occurrence of EGFP+ PaSCs in injured mice. We propose that CCR2+ monocytes migrate into the pancreas possibly via the MCP-1/CCR2 pathway and give rise to PaSCs.

Splenectomy increases the number of circulating hematopoietic stem/progenitor cells in patients with hepatitis C virus-associated liver cirrhosis

The spleen is not believed to contribute to hematopoiesis in healthy adults. However, several reports have demonstrated that the spleen in adults contains a large number of hematopoietic stem/progenitor cells (HSC). Although splenectomy increases platelet and leukocyte counts, the effects of splenectomy on circulating HSC have not been elucidated. In this study, we evaluated the association between the number of circulating HSC and splenectomy in patients with hepatitis C virus (HCV)‐associated liver cirrhosis (LC).

Bacteremia due to Leuconostoc pseudomesenteroides in a Patient with Acute Lymphoblastic Leukemia: Case Report and Review of the Literature.

Leuconostoc species are vancomycin-resistant Gram-positive cocci. Infections due to Leuconostoc species have been reported in various immunocompromised patients, but little is known about such infection in patients with hematologic malignancies. We report a case of Leuconostoc infection in a 44-year-old woman with acute lymphoblastic leukemia. The patient developed a high fever despite antimicrobial therapy with doripenem after induction chemotherapy. After an isolate from blood cultures was identified as L. pseudomesenteroides, we changed the antibiotics to piperacillin-tazobactam and gentamicin, after which the patient recovered from the infection. Physicians should be aware of Leuconostoc species as causative pathogen if they encounter Gram-positive cocci bacteremia resistant to standard antibiotics such as vancomycin and teicoplanin, especially in patients with hematologic malignancies.

Ly6C+ monocytes are extrahepatic precursors of hepatic stellate cells in the injured liver of mice

OBJECTIVE We previously reported that hepatic stellate cells (HpSCs) are of hematopoietic origin in liver injury. However, the immediate precursors of HpSCs remain unknown. This study was conducted to elucidate whether terminally differentiated blood cells can differentiate into HpSCs. MATERIALS AND METHODS We adoptively transferred a variety of cells isolated from enhanced green fluorescent protein (EGFP)-transgenic mice into carbon tetrachloride (CCl(4))-treated nontransgenic mice twice weekly for 2 weeks. We examined the presence of EGFP(+) HpSCs in the injured liver using immunofluorescence analysis. RESULTS Monocytes, neutrophils, eosinophils, B cells, or T cells from EGFP mice were transferred into CCl(4)-treated mice. Thirty percent of EGFP(+) cells in the livers of mice given Ly6C(high)c-kit(-) monocytes were negative for CD45, but were positive for glial fibrillary acidic protein, desmin, CD146, ADAMTS13, and α-smooth muscle actin, well-known markers of HpSCs. EGFP(+)CD45(-) cells were predominantly positive for glial fibrillary acidic protein. Although 48% of EGFP(+) cells were positive for procollagen type I, half of them were CD45(-). In the livers of mice given neutrophils, eosinophils, B cells, or T cells, all of the EGFP(+) cells were CD45(+). The majority of EGFP(+) cells in the nonparenchymal cell fraction purified from the livers of mice given Ly6C(high)c-kit(-) monocytes contained lipid droplets and were positive for glial fibrillary acidic protein, desmin, ADAMTS13, and procollagen type I. When Ly6C(+) monocyte-depleted peripheral blood total nucleated cells were adoptively transferred into CCl(4)-treated mice, we found no EGFP(+)CD45(-) cells in the liver. CONCLUSIONS These results suggest that Ly6C(+) monocytes can become HpSCs in the injured liver.

Alcoholic ketoacidosis that developed with a hypoglycemic attack after eating a high‐fat meal

Alcoholic ketoacidosis (AKA) usually occurs in patients with a history of prolonged alcohol abuse and recent binge drinking followed by abrupt cessation of alcohol consumption.