Shinya Rai

The Clathrin Assembly Protein PICALM Is Required for Erythroid Maturation and Transferrin Internalization in Mice

Phosphatidylinositol binding clathrin assembly protein (PICALM), also known as clathrin assembly lymphoid myeloid leukemia protein (CALM), was originally isolated as part of the fusion gene CALM/AF10, which results from the chromosomal translocation t(10;11)(p13;q14). CALM is sufficient to drive clathrin assembly in vitro on lipid monolayers and regulates clathrin-coated budding and the size and shape of the vesicles at the plasma membrane. However, the physiological role of CALM has yet to be elucidated. Here, the role of CALM in vivo was investigated using CALM-deficient mice. CALM-deficient mice exhibited retarded growth in utero and were dwarfed throughout their shortened life-spans. Moreover, CALM-deficient mice suffered from severe anemia, and the maturation and iron content in erythroid precursors were severely impaired. CALM-deficient erythroid cells and embryonic fibroblasts exhibited impaired clathrin-mediated endocytosis of transferrin. These results indicate that CALM is required for erythroid maturation and transferrin internalization in mice.

Clathrin Assembly Protein CALM Plays a Critical Role in KIT Signaling by Regulating Its Cellular Transport from Early to Late Endosomes in Hematopoietic Cells

CALM is implicated in the formation of clathrin-coated vesicles, which mediate endocytosis and intracellular trafficking of growth factor receptors and nutrients. We previously found that CALM-deficient mice suffer from severe anemia due to the impaired clathrin-mediated endocytosis of transferrin receptor in immature erythroblast. However, CALM has been supposed to regulate the growth and survival of hematopoietic stem/progenitor cells. So, in this study, we focused on the function of CALM in these cells. We here show that the number of Linage−Sca-1+KIT+ (LSK) cells decreased in the fetal liver of CALM −/− mice. Also, colony forming activity was impaired in CALM−/− LSK cells. In addition, SCF, FLT3, and TPO-dependent growth was severely impaired in CALM−/− LSK cells, while they can normally proliferate in response to IL-3 and IL-6. We also examined the intracellular trafficking of KIT using CALM −/− murine embryonic fibroblasts (MEFs) engineered to express KIT. At first, we confirmed that endocytosis of SCF-bound KIT was not impaired in CALM −/− MEFs by the internalization assay. However, SCF-induced KIT trafficking from early to late endosome was severely impaired in CALM −/− MEFs. As a result, although intracellular KIT disappeared 30 min after SCF stimulation in wild-type (WT) MEFs, it was retained in CALM −/− MEFs. Furthermore, SCF-induced phosphorylation of cytosolic KIT was enhanced and prolonged in CALM −/− MEFs compared with that in WT MEFs, leading to the excessive activation of Akt. Similar hyperactivation of Akt was observed in CALM −/− KIT+ cells. These results indicate that CALM is essential for the intracellular trafficking of KIT and its normal functions. Also, our data demonstrate that KIT located in the early endosome can activate downstream molecules as a signaling endosome. Because KIT activation is involved in the pathogenesis of some malignancies, the manipulation of CALM function would be an attractive therapeutic strategy.

Loss of genomic DNA copy numbers in the p18 , p16 , p27 and RB loci in blastic plasmacytoid dendritic cell neoplasm

ejd.2012.1663 Auteur(s) : Naoki Oiso1 naoiso@med.kindai.ac.jp, Yoichi Tatsumi2, Tokuzo Arao3, Shinya Rai2, Masatomo Kimura4, Shigeo Nakamura5, Tomoo Itoh6, Kazuto Nishio3, Itaru Matsumura2, Akira Kawada1 1 Department of Dermatology, 2 Hematology, 3 Genome Biology, 4 Pathology, Kinki University Faculty of Medicine, 377-2 Ohno-Higashi, Osaka-Sayama 589-8511, Japan 5 Department of Diagnostic Pathology, Nagoya School of Medicine, Nagoya, Japan 6 Department of Pathology, Kobe University Graduate School [...]

Superimposed linear graft-versus-host disease and secondary cutaneous involvement of anaplastic large cell lymphoma

ejd.2011.1410 Auteur(s) : Naoki Oiso1 naoiso@med.kindai.ac.jp, Yoichi Tatsumi2, Shinya Rai2, Itaru Matsumura2, Akira Kawada1 1 Department of Dermatology, Kinki University Faculty of Medicine, 377-2 Ohno-Higashi, Osaka-Sayama 589-8511, Japan 2 Department of Hematology, Kinki University Faculty of Medicine, 377-2 Ohno-Higashi, Osaka-Sayama 589-8511, Japan Superimposed linear graft-versus-host disease (GVHD) is rarely present in recipients of allogeneic bone-marrow transplantation as an early lichenoid [...]

Mice doubly-deficient in the Arf GAPs SMAP1 and SMAP2 exhibit embryonic lethality.

In mammals, the small Arf GTPase‐activating protein (SMAP) subfamily of Arf GTPase‐activating proteins consists of closely related members, SMAP1 and SMAP2. These factors reportedly exert distinct functions in membrane trafficking, as manifested by different phenotypes seen in single knockout mice. The present study investigated whether SMAP proteins interact genetically. We report for the first time that simultaneous loss ofSMAP1 andSMAP2 promotes apoptosis in the distal region of E7.5 mouse embryos, likely resulting in embryonic lethality. Thus, at least oneSMAP gene, eitherSMAP1 orSMAP2, is required for proper embryogenesis.

Cytokine profiles in relapsed multiple myeloma patients undergoing febrile reactions to lenalidomide

Lenalidomide plays a central role in the treatment of multiple myeloma (MM). Ozaki et al. [1] very recently reported two cases that had developed inflammatory reactions to lenalidomide. We also experienced three similar cases among eight cases treated in our hospital from August 2010 to July 2011 (Table 1). Case 1 received lenalidomide (10 mg/day on days 1–21) plus dexamethasone (20 mg on days 1–4) on a 28-day cycle. On day 7 at cycle 1, the patient developed high fever without apparent infection. After tapering the dose of lenalidomide to 5 mg/day without administration of antibiotics, his fever slowly receded. Case 2 received lenalidomide monotherapy (15 mg/day on days 1–21) on a 28-day cycle. On day 14 at cycle 1, the patient developed mild fever without focus of infection. We reduced the dose to 10 mg/day. The fever subsequently receded. Case 3 received lenalidomide (15 mg/day on days 1–21) plus dexamethasone (8 mg on days 1–4) on a 28-day cycle. On day 6 at cycle 1, the patient developed high fever without focus of infection. Five days after stopping lenalidomide, the fever receded. Cases 4–8 received lenalidomide (15 mg on days 1–21) plus dexamethasone therapy (20 mg/day on days 1, 8, 15, 22) on a 28-day cycle. The patient in Case 4 developed high fever due to the oral cavity infection on day 15, while febrile events were not observed in Cases 5–8. To clarify the mechanism underlying the febrile reactions to lenalidomide, we measured serum cytokine levels in these cases by enzyme-linked immunosorbent assay (ELISA) in SRL, Inc. (Tokyo, Japan) using residual serum samples, after obtaining informed consent. As for Cases 1–3, lenalidomide alone or in combination with dexamethasone drastically reduced serum tumor necrosis factor (TNF)-a levels in spite of the febrile reactions (12.2–1.5 pg/ml in Case 1; 2.9–1.8 pg/ml in Case 2; 71.0 to 4.5 pg/ml in Case 3) (Table 1). Lenalidomide also dramatically decreased serum interleukin (IL)-6 levels in Cases 1 and 2 (200.0–8.0 pg/ml in Case 1; 9.0–4.2 pg/ml in Case 2), but not in Case 3 (2.4–54.7 pg/ml). Levels of other cytokines, including pro-inflammatory cytokine IL-1b and anti-inflammatory cytokine IL-10, were scarcely influenced by lenalidomide in these three cases. These results indicate that, although the cytokine(s) involved in the febrile reactions to lenalidomide remains unknown, it appears that, except for the possible involvement of IL-6 in Case 3, these reactions were caused independently of IL-6 and TNF-a. Similarly, lenalidomide reduced serum levels of TNF-a and IL-6 in Cases 4–8, whereas their degrees were considerably different among the cases. Although we cannot deny the possibility that dexamethasone influences the serum cytokine levels, it is believed that serum IL-6 and TNF-a levels are reduced by the standard combination therapy with lenalidomide and dexamethasone in most MM patients. We also examined whether anti-MM effects of lenalidomide might not be affected by the febrile reactions. However, after one cycle of lenalidomide treatment, the % M-protein Y. Morita (&) T. Shimada T. Yamaguchi S. Rai C. Hirase M. Emoto K. Serizawa Y. Taniguchi M. Ojima Y. Tatsumi T. Ashida I. Matsumura Division of Hematology, Department of Internal Medicine, Kinki University Faculty of Medicine, Osaka-Sayama, Osaka 589-8511, Japan e-mail: moriyasu@med.kindai.ac.jp

Genital Infection as a First Sign of Acute Myeloid Leukemia

Fournier’s gangrene is a life-threatening disorder caused by aerobic and anaerobic bacterial infection. We report a case of genital infection as the initial warning sign of acute myeloid leukemia. We were able to prevent progression to Fournier’s gangrene in our patient by immediate intensive therapy with incision, blood transfusions and intravenous administration of antibiotics. This case suggests that hematologists and dermatologists should keep in mind that genital infection can be a first sign of hematologic malignancy.

HIV-negative Primary Bone Marrow Hodgkin Lymphoma Manifesting with a High Fever Associated with Hemophagocytosis as the Initial Symptom: A Case Report and Review of the Previous Literature

A 68-year-old man was referred to our hospital due to a high fever and pancytopenia. Neither tumors nor infectious lesions were detected. Hemophagocytosis was observed on the bone marrow (BM) smear, although without abnormal cells. Prednisolone therapy was ineffective for the patients high fever. Later on, we obtained the results of a BM biopsy indicating the presence of infiltration of atypical Reed-Sternberg cells, leading to a diagnosis of HIV-negative primary bone marrow Hodgkin lymphoma (PBMHL). However, the patient died of multiple organ failure before receiving chemotherapy. As the clinical course of PBMHL is rapid, physicians must keep in mind its possibility in similar cases.