The KDM3A-KLF2-IRF4 axis maintains myeloma cell survival

KDM3A is implicated in tumorigenesis; however, its biological role in multiple myeloma (MM) has not been elucidated. Here we identify KDM3A–KLF2–IRF4 axis dependence in MM. Knockdown of KDM3A is toxic to MM cells in vitro and in vivo. KDM3A maintains expression of KLF2 and IRF4 through H3K9 demethylation, and knockdown of KLF2 triggers apoptosis. Moreover, KLF2 directly activates IRF4 and IRF4 reciprocally upregulates KLF2, forming a positive autoregulatory circuit. The interaction of MM cells with bone marrow milieu mediates survival of MM cells. Importantly, silencing of KDM3A, KLF2 or IRF4 both decreases MM cell adhesion to bone marrow stromal cells and reduces MM cell homing to the bone marrow, in association with decreased ITGB7 expression in MAF-translocated MM cell lines. Our results indicate that the KDM3A–KLF2–IRF4 pathway plays an essential role in MM cell survival and homing to the bone marrow, and therefore represents a therapeutic target.

Several histone modifiers have been implicated in the survival of multiple myeloma cells. Here, the authors reveal a role for the histone demethylase KDM3A in the survival of this haematologic cancer, and show that mechanistically KDM3A removes H3K9 methylation from the promoters of KLF2 and IRF4, genes essential for myeloma cell survival.

Advanced Lymphocyte-rich Classical Hodgkin Lymphoma Complicated with Fatal Hemophagocytic Syndrome

Lymphocyte-rich classical Hodgkin lymphoma (LRCHL) is a rare subtype of Hodgkin lymphoma with a favorable prognosis, and an aggressive clinical course of LRCHL is uncommon. A 55-year-old man suffering from swelling in the left neck was diagnosed with LRCHL with extranodal lesions in the lung and bone marrow. Initially, he received standard ABVD chemotherapy; however, disease progression, accompanied by hemophagocytic syndrome (HPS), occurred during the second course of ABVD. He received two subsequent courses of intensive chemotherapy containing high-dose steroids, cyclophosphamide, and etoposide. Nevertheless, this therapy was only temporarily effective, and he died of due to an aggressive disease progression accompanied by uncontrollable HPS and severe coagulopathy.

Activation of the NLRP3 inflammasome by cellular labile iron

Cellular labile iron, which contains chelatable redox-active Fe(2+), has been implicated in iron-mediated cellular toxicity leading to multiple organ dysfunction. Iron homeostasis is controlled by monocytes/macrophages through their iron recycling and storage capacities. Furthermore, iron sequestration by monocytes/macrophages is regulated by pro-inflammatory cytokines including interleukin-1, highlighting the importance of these cells in the crosstalk between inflammation and iron homeostasis. However, a role for cellular labile iron in monocyte/macrophage-mediated inflammatory responses has not been defined. Here we describe how cellular labile iron activates the NLRP3 inflammasome in human monocytes. Stimulation of lipopolysaccharide-primed peripheral blood mononuclear cells with ferric ammonium citrate increases the level of cellular Fe(2+) levels in monocytes and induces production of interleukin-1β in a dose-dependent manner. This ferric ammonium citrate-induced interleukin-1β production is dependent on caspase-1 and is significantly inhibited by an Fe(2+)-specific chelator. Ferric ammonium citrate consistently induced interleukin-1β secretion in THP1 cells, but not in NLRP3-deficient THP1 cells, indicating a requirement for the NLRP3 inflammasome. Additionally, activation of the inflammasome is mediated by potassium efflux, reactive oxygen species-mediated mitochondrial dysfunction, and lysosomal membrane permeabilization. Thus, these results suggest that monocytes/macrophages not only sequestrate iron during inflammation, but also mediate inflammation in response to cellular labile iron, which provides novel insights into the role of iron in chronic inflammation.

[Update on the biology of heme synthesis in erythroid cells]

Heme is a prosthetic group of hemoproteins playing important roles in oxygen transport, detoxification, circadian rhythm, microRNA processing, regulation of transcription, and translation. The majority of heme (-85%) is synthesized in red blood cells mainly for hemoglobin production, whereas hepatocytes account for most of the rest, functioning primarily in the synthesis of cytochrome P450 enzymes and mitochondrial respiratory enzymes. Thus, failure of heme biosynthesis causes severe inherited or acquired disorders in humans, including porphyria and sideroblastic anemia. The heme biosynthetic pathway is composed of eight enzymes that work in either mitochondria or the cytoplasm, which have been extensively researched and frequently reviewed. On the other hand, the mechanisms governing transport and intracellular trafficking of heme intermediates, as well as their potential links to human diseases, are poorly understood. Herein, we focus on recent understanding of the heme biosynthetic pathway and on human disorders due to defective heme synthesis in erythroid cells, such as X-linked sideroblastic anemia and erythropoietic protoporphyria.

Retrospective analysis of 95 patients with large vessel vasculitis: a single center experience

AIM

Although Takayasu arteritis (TAK) and giant cell arteritis (GCA) have been considered as distinct disease entities, similarities of these diseases have been recently reported. However, little data is available regarding this issue in Japanese patients with TAK and GCA. In addition, the classification criteria for TAK established in 1990 by the American College of Rheumatology (ACR) have been criticized due to the age restriction for disease onset (≤ 40 years). Thus, we aimed to compare the clinical characteristics of Japanese patients with TAK and those with GCA and to clarify whether clinical differences existed between patients with early-onset (≤ 40 years) and late-onset (> 40 years) TAK.

METHODS

We enrolled 86 patients with TAK and nine with GCA who visited our department from 1990 to 2014. The diagnoses of TAK and GCA were based on the criteria of the Japanese Circulation Society and the ACR, respectively.

RESULTS

Mean ages at onset for TAK and GCA were 36.4 and 71.0 years, respectively. Patients with TAK had significantly higher incidences of aortic regurgitation and carotid and subclavian arterial involvement, lower frequencies of polymyalgia rheumatica, and better prognoses than those with GCA. In contrast, the clinical characteristics, distribution of arterial lesions, treatments administered, and prognoses of patients with early- and late-onset TAK were comparable.

CONCLUSIONS

These results suggested that TAK and GCA differed substantially, and that the age restriction (≤ 40 years) may not be necessary for the diagnosis of TAK.

High-Throughput siRNA Screening to Reveal GATA-2 Upstream Transcriptional Mechanisms in Hematopoietic Cells

Hematopoietic stem cells can self-renew and differentiate into all blood cell types. The transcription factor GATA-2 is expressed in both hematopoietic stem and progenitor cells and is essential for cell proliferation, survival, and differentiation. Recently, evidence from studies of aplastic anemia, MonoMAC syndrome, and lung cancer has demonstrated a mechanistic link between GATA-2 and human pathophysiology. GATA-2-dependent disease processes have been extensively analyzed; however, the transcriptional mechanisms upstream of GATA-2 remain less understood. Here, we conducted high-throughput small-interfering-RNA (siRNA) library screening and showed that YN-1, a human erythroleukemia cell line, expressed high levels of GATA-2 following the activation of the hematopoietic-specific 1S promoter. As transient luciferase reporter assay in YN-1 cells revealed the highest promoter activity in the 1S promoter fused with GATA-2 intronic enhancer (+9.9 kb/1S); therefore, we established a cell line capable of stably expressing +9.9 kb/1S-Luciferase. Subsequently, we screened 995 transcription factor genes and revealed that CITED2 acts as a GATA-2 activator in human hematopoietic cells. These results provide novel insights into and further identify the regulatory mechanism of GATA-2.

A prospective analysis of clinical efficacy and safety in chronic myeloid leukemia-chronic phase patients with imatinib resistance or intolerance as evaluated using European LeukemiaNet 2013 criteria

BACKGROUND

We conducted a phase II study to evaluate the efficacy and safety of dasatinib in Japanese patients with imatinib-resistant or imatinib-intolerant chronic myeloid leukemia (CML).

METHODS

From 2009 to 2011, 54 CML-chronic phase (CP) patients with resistance (n = 40) or intolerance (n = 25) to imatinib were registered to undergo dasatinib treatment. Eleven patients showed both resistance and intolerance to imatinib. Coincidentally, the resistance criteria in this study were the same as a non-optimal response to tyrosine kinase inhibitors (TKIs) as defined in the European LeukemiaNet (ELN) 2013 recommendations.

RESULTS

The overall incidence rate of major molecular response (MMR) at 12 months was 62.3% (n = 47). Forty patients with resistance to imatinib who were 'warning' and 'failure' patients based on the ELN 2013 recommendations were assessed; cumulative MMR and MR(4.5) rates were 62.5% (n = 39) and 21.0% (n = 40), respectively, at 12 months. Twelve patients who showed a BCR-ABL transcript level >1% on the international scale did not achieve a MMR or discontinued dasatinib treatment because of insufficient effects. With regard to safety issues, grade 3/4 non-hematologic adverse events (AEs) were infrequent.

CONCLUSIONS

Patients with non-optimal responses (who meet ELN 2013 warning and failure criteria) to imatinib should be switched quickly to dasatinib, which is less toxic in CML-CP patients, to improve their prognoses. A BCR-ABL1 IS of <1% at 3 months of dasatinib administration is a landmark for good therapeutic outcome.

Analysis of clinical characteristics and prognostic factors for angioimmunoblastic T-cell lymphoma

Angioimmunoblastic T-cell lymphoma (AITL) is a distinct peripheral T-cell lymphoma entity exhibiting peculiar clinical features and poor prognosis. Its clinical characteristics and prognostic factors are not well established. To clarify the clinical characteristics and prognostic features of AITL, we conducted a multicenter, retrospective study. Fifty-six patients were enrolled. The median patient age was 68 years. Immunohistochemical examinations of tumor cells showed positivity for CD10 and T-cell markers, and chromosomal examination detected several types of abnormalities. More than 80 % of patients show advanced disease at diagnosis and poor prognostic scores. A high proportion of patients showed accompanying B symptoms, splenomegaly, and hepatomegaly at diagnosis. The 5-year overall survival (OS) rate was 48 % and progression-free survival was 25 %. Univariate analysis revealed higher age, fever, poor performance status, anemia, and low albumin level to be poor prognostic factors for OS. In addition to these factors, both IPI and PIT were also predictive of OS. Multivariate analysis indicated only a low level of serum albumin to be a significant prognostic factor for OS. Serum albumin may be one of the important prognostic factors for AITL. Further investigation is needed to confirm these results.

Human CD43+ B cells are closely related not only to memory B cells phenotypically but also to plasmablasts developmentally in healthy individuals

CD20(+)CD27(+)CD43(+) B (CD43(+) B) cells have been newly defined among PBMCs and proposed to be human B1 cells. However, it is controversial as to whether they are orthologs of murine B1 cells and how they are related to other B-cell populations, particularly CD20(+)CD27(+)CD43(-) memory B cells and CD20(low)CD27(high)CD43(high) plasmablasts. Our objective is to identify phenotypically the position of CD43(+) B cells among peripheral B-lineage cell compartments in healthy donors, with reference to B-cell subsets from patients with systemic lupus erythematosus (SLE). We found that CD43(+) B cells among PBMCs from healthy subjects were indistinguishable phenotypically from memory B cells in terms of surface markers, and spontaneous in vitro Ig and IL-10 secretion capability, but quite different from plasmablasts. However, a moderate correlation was found in the frequency of CD43(+) B cells with that of plasmablasts in healthy donors but not in SLE patients. An in vitro differentiation experiment indicated that CD43(+) B cells give rise to plasmablasts more efficiently than do memory B cells, suggesting that they are more closely related to plasmablasts developmentally than are memory B cells, which is also supported by quantitative PCR analysis of mRNA expression of B-cell and plasma cell signature genes. Thus, we conclude that, in healthy individuals, CD43(+) B cells are closely related not only to memory B cells phenotypically but also to plasmablasts developmentally, although the developmental origin of CD43(+) B cells is not necessarily the same as that of plasmablasts.

Prevalence of hepatitis B virus infection in patients with rheumatic diseases in Tohoku area: a retrospective multicenter survey

Hepatitis B virus (HBV) reactivation has been increasingly recognized in patients receiving chemotherapy and immunosuppressive therapy; however, the prevalence of HBV infection and rate of HBV screening in patients with rheumatic diseases remains unclear. In this study, we aimed to assess the prevalence of HBV infection and fulminant HBV hepatitis in patients with rheumatic diseases. We also investigated the rate of HBV screening before immunosuppressive therapy in patients with rheumatic diseases. A retrospective questionnaire survey was conducted in the North-east area (Tohoku) of Japan. Questionnaires, comprising 6 questions, were sent to 318 rheumatologists in May 2010, and responses were gathered until June 2011. In total, 71 rheumatologists (22.3%) responded to the survey. We enrolled 7,650 patients with rheumatoid arthritis (RA) and 1,031 patients with systemic lupus erythematosus (SLE). When limited to institutes at which almost all (≥ 90%) patients were tested for HBV serology, 1.1% (40/3,580) patients with RA and 0.3% (3/1,128) patients with SLE were positive for hepatitis B surface antigen (HBsAg), and 25.2% (177/703) patients with RA and 13.7% (34/248) patients with SLE were positive for hepatitis B core antibody (HBcAb). About one-third of rheumatologists did not check HBsAg and more than half did not check hepatitis B surface antibody (HBsAb) or HBcAb at all before therapy. Fulminant HBV hepatitis was observed in 1 RA patient who was current HBV carrier. In conclusion, the prevalence of HBV infection is high in patients with RA and SLE. HBV screening before immunosuppressive therapy should be strictly performed.

Synovitis in a Patient with IgG4-related Disease

A 71-year-old man was admitted to our department due to arthralgia and renal dysfunction. A physical examination disclosed swelling of the right shoulder and left wrist joints. Laboratory tests showed elevated serum IgG4 and creatinine levels, and magnetic resonance imaging of the wrist revealed bone erosion and synovitis. In addition, fluorodeoxyglucose positron emission tomography showed uptake in the submandibular glands, pancreas, kidneys, and affected joints and a renal biopsy revealed tubulointerstitial nephritis with the infiltration of IgG4+ plasma cells. The patient was subsequently diagnosed with IgG4-related disease (IgG4-RD) and successfully treated with corticosteroid therapy. This case suggests that erosive arthritis may occur in patients with IgG4-RD.

Fatal visceral varicella-zoster developing early after autologous hematopoietic stem cell transplantation for refractory diffuse large B-cell lymphoma

A middle-aged woman who had undergone autologous hematopoietic stem cell transplantation (HSCT) 1 month previously suffered severe epigastralgia and relapse of lymphoma. The epigastralgia was not relieved by chemotherapy. Thereafter, her pancreatic and hepatic enzyme levels were markedly elevated and disseminated varicella emerged. Despite acyclovir administration, her general condition deteriorated rapidly and she died. Serum varicella zoster virus (VZV) DNA level was shown to be elevated and a diagnosis of disseminated VZV infection was established postmortem. In patients with severe abdominal pain following HSCT, early suspicion and therapeutic intervention for VZV are important, even in the absence of skin lesions.

Effect of 5-aminolevulinic acid on erythropoiesis: a preclinical in vitro characterization for the treatment of congenital sideroblastic anemia

Congenital sideroblastic anemia (CSA) is a hereditary disorder characterized by microcytic anemia and bone marrow sideroblasts. The most common form of CSA is attributed to mutations in the X-linked gene 5-aminolevulinic acid synthase 2 (ALAS2). ALAS2 is a mitochondrial enzyme, which utilizes glycine and succinyl-CoA to form 5-aminolevulinic acid (ALA), a crucial precursor in heme synthesis. Therefore, ALA supplementation could be an effective therapeutic strategy to restore heme synthesis in CSA caused by ALAS2 defects. In a preclinical study, we examined the effects of ALA in human erythroid cells, including K562 cells and human induced pluripotent stem cell-derived erythroid progenitor (HiDEP) cells. ALA treatment resulted in significant dose-dependent accumulation of heme in the K562 cell line. Concomitantly, the treatment substantially induced erythroid differentiation as assessed using benzidine staining. Quantitative reverse transcription polymerase chain reaction (RT-PCR) analysis confirmed significant upregulation of heme-regulated genes, such as the globin genes [hemoglobin alpha (HBA) and hemoglobin gamma (HBG)] and the heme oxygenase 1 (HMOX1) gene, in K562 cells. Next, to investigate the mechanism by which ALA is transported into erythroid cells, quantitative RT-PCR analysis was performed on previously identified ALA transporters, including solute carrier family 15 (oligopeptide transporter), member (SLC15A) 1, SLC15A2, solute carrier family 36 (proton/amino acid symporter), member (SLC36A1), and solute carrier family 6 (neurotransmitter transporter), member 13 (SLC6A13). Our analysis revealed that SLC36A1 was abundantly expressed in erythroid cells. Thus, gamma-aminobutyric acid (GABA) was added to K562 cells to competitively inhibit SLC36A1-mediated transport. GABA treatment significantly impeded the ALA-mediated increase in the number of hemoglobinized cells as well as the induction of HBG, HBA, and HMOX1. Finally, small-interfering RNA-mediated knockdown of ALAS2 in HiDEP cells considerably decreased the expression of HBA, HBG, and HMOX1, and these expression levels were rescued with ALA treatment. In summary, ALA appears to be transported into erythroid cells mainly by SLC36A1 and is utilized to generate heme. ALA may represent a novel therapeutic option for CSA treatment, particularly for cases harboring ALAS2 mutations.

OX40 and IL-7 play synergistic roles in the homeostatic proliferation of effector memory CD4⁺ T cells

T-cell homeostasis preserves the numbers, the diversity and functional competence of different T-cell subsets that are required for adaptive immunity. Naïve CD4(+) T (TN ) cells are maintained in the periphery via the common γ-chain family cytokine IL-7 and weak antigenic signals. However, it is not clear how memory CD4(+) T-cell subsets are maintained in the periphery and which factors are responsible for the maintenance. To examine the homeostatic mechanisms, CFSE-labeled CD4(+) CD44(high) CD62L(low) effector memory T (TEM ) cells were transferred into sublethally-irradiated syngeneic C57BL/6 mice, and the systemic cell proliferative responses, which can be divided distinctively into fast and slow proliferations, were assessed by CFSE dye dilution. We found that the fast homeostatic proliferation of TEM cells was strictly regulated by both antigen and OX40 costimulatory signals and that the slow proliferation was dependent on IL-7. The simultaneous blockade of both OX40 and IL-7 signaling completely inhibited the both fast and slow proliferation. The antigen- and OX40-dependent fast proliferation preferentially expanded IL-17-producing helper T cells (Th17 cells). Thus, OX40 and IL-7 play synergistic, but distinct roles in the homeostatic proliferation of CD4(+) TEM cells.

GATA2 regulates differentiation of bone marrow-derived mesenchymal stem cells

The bone marrow microenvironment comprises multiple cell niches derived from bone marrow mesenchymal stem cells. However, the molecular mechanism of bone marrow mesenchymal stem cell differentiation is poorly understood. The transcription factor GATA2 is indispensable for hematopoietic stem cell function as well as other hematopoietic lineages, suggesting that it may maintain bone marrow mesenchymal stem cells in an immature state and also contribute to their differentiation. To explore this possibility, we established bone marrow mesenchymal stem cells from GATA2 conditional knockout mice. Differentiation of GATA2-deficient bone marrow mesenchymal stem cells into adipocytes induced accelerated oil-drop formation. Further, GATA2 loss- and gain-of-function analyses based on human bone marrow mesenchymal stem cells confirmed that decreased and increased GATA2 expression accelerated and suppressed bone marrow mesenchymal stem cell differentiation to adipocytes, respectively. Microarray analysis of GATA2 knockdowned human bone marrow mesenchymal stem cells revealed that 90 and 189 genes were upregulated or downregulated by a factor of 2, respectively. Moreover, gene ontology analysis revealed significant enrichment of genes involved in cell cycle regulation, and the number of G1/G0 cells increased after GATA2 knockdown. Concomitantly, cell proliferation was decreased by GATA2 knockdown. When GATA2 knockdowned bone marrow mesenchymal stem cells as well as adipocytes were cocultured with CD34-positive cells, hematopoietic stem cell frequency and colony formation decreased. We confirmed the existence of pathological signals that decrease and increase hematopoietic cell and adipocyte numbers, respectively, characteristic of aplastic anemia, and that suppress GATA2 expression in hematopoietic stem cells and bone marrow mesenchymal stem cells.

[Points of revision of the guideline JSLM 2012]

The revised version of the guideline JSLM 2012 was published in December 2012 by the Japanese Society of Laboratory Medicine. This version included new sections, such as blood gas analysis, sleep apnea syndrome, interstitial lung disease, liver and pancreas cancer, chronic kidney disease, acute kidney disease, gout and hyperuricemia, bone metabolism abnormality, malignant lymphoma, and rheumatoid arthritis. The guideline committee was composed of specialists in each field of internal medicine, who were responsible for selecting and requesting the authors and also in promoting and proofreading the manuscripts. In special program I at the 60th annual meeting, each specialist gave lectures concerning the points of the revision in their fields. The questionnaire surveys were performed using FAX or the Internet. Analysis of eighty-seven (2.5%) responses from 3,500 individuals/facilities, which were sent the guideline, revealed that this guideline was graded as excellent by 38 readers, fair by 42, and average by in 6. Significant opinions on the guideline were obtained from the readers, and they will be the bases for the next revision. The main subjects of this guideline were confirmed to be the residents and general physicians, by whom it is hoped the routine laboratory tests will be properly utilized. Therefore, based on the section of 'approach of the laboratory test results', which is a representative characteristic of this guideline, the sections of 'symptoms' will be fulfilled for the next version. This guideline needs to be periodically revised with advances in medicine.