Crk-Associated Substrate Lymphocyte Type Is Required for Lymphocyte Trafficking and Marginal Zone B Cell Maintenance

The lymphocyte-specific Cas family protein Cas-L (Crk-associated substrate lymphocyte type) has been implicated to function in lymphocyte movement, mediated mainly by integrin signaling. However, its physiological role is poorly understood. In this study we analyzed the function of Cas-L in lymphocytes using gene-targeted mice. The mutant mice showed a deficit of marginal zone B (MZB) cells and a decrease of cell number in secondary lymphoid organs. An insufficient chemotactic response and perturbed cell adhesion were observed in Cas-L-deficient lymphocytes, suggesting that the aberrant localization was responsible for the deficit of MZB cells. Moreover, we found that lymphocyte trafficking was altered in Cas-L-deficient mice, which gave a potential reason for contraction of secondary lymphoid tissues. Thus, Cas-L affects homeostasis of MZB cells and peripheral lymphoid organs, which is considered to be relevant to impaired lymphocyte migration and adhesion.

Cloning and characterization of the novel chimeric gene TEL/PTPRR in acute myelogenous leukemia with inv(12)(p13q13)

We have cloned a novel TEL/protein tyrosine phosphatase receptor-type R (PTPRR) chimeric gene generated by inv(12)(p13q13). PTPRR is the first protein tyrosine phosphatase identified as a fusion partner of TEL. The chimeric gene fused exon 4 of the TEL gene with exon 7 of the PTPRR gene, and produced 10 isoforms through alternative splicing. Two isoforms that were expressed at the highest level in the leukemic cells could have been translated into COOH-terminally truncated TEL protein possessing the helix-loop-helix domain (tTEL) and TEL/PTPRR chimeric protein linking the helix-loop-helix domain of TEL to the catalytic domain of PTPRR. These two mutant proteins exerted a dominant-negative effect over transcriptional repression mediated by wild-type TEL, although they themselves did not show any transcriptional activity. Heterodimerization with wild-type TEL might be an underlying mechanism in this effect. TEL/PTPRR did not exhibit any tyrosine phosphatase activity. Importantly, overexpression of TEL/PTPRR in granulocyte macrophage colony-stimulating factor-dependent UT7/GM cells resulted in their factor-independent proliferation, whereas overexpression of tTEL did not. After cytokine depletion, phosphorylated signal transducers and activators of transcription 3 (STAT3) significantly declined in mock cells, but remained in both tTEL- and TEL/PTPRR-overexpressing cells. Loss of tumor suppressive function of wild-type TEL and maintenance of STAT3-mediated signal could at least partly contribute to the leukemogenesis caused by inv(12)(p13q13).

Fully automated analysis of estrogens in environmental waters by in-tube solid-phase microextraction coupled with liquid chromatography–tandem mass spectrometry

A simple, rapid and sensitive method for the determination of five estrogens, estrone, 17beta-estradiol, estriol, ethynyl estradiol, and diethylstilbestrol, was developed using a fully automated method consisting of in-tube solid-phase microextraction (SPME) coupled with liquid chromatography-tandem mass spectrometry (LC/MS/MS). These estrogens were separated within 8 min by HPLC using an XDB-C8 column and 0.01% ammonia/acetonitrile (60/40, v/v) at a flow rate of 0.2 mL/min. Electrospray ionization conditions in the negative ion mode were optimized for MS/MS detection of the estrogens. The optimum in-tube SPME conditions were 20 draw/eject cycles of 40 microL of sample using a Supel-Q PLOT capillary column as an extraction device. The extracted compounds were easily desorbed from the capillary by passage of the mobile phase, and no carryover was observed. Using the in-tube SPME LC/MS/MS method, good linearity of the calibration curve (r > or = 0.9996) was obtained in the concentration range from 10 to 200 pg/mL for all compounds examined. The limits of detection (S/N= 3) of the five estrogens examined ranged from 2.7 to 11.7 pg/mL. The in-tube SPME method showed 34-90-fold higher sensitivity than the direct injection method (5 microL injection). This method was applied successfully to the analysis of environmental water samples without any other pretreatment and interference peaks. Several surface water and wastewater samples were collected from the area around Asahi River, and estriol was detected at 35.7 pg/mL in the effluent of a sewage treatment plant. The recoveries of estrogens spiked into river waters were above 86%, except for estriol, and the relative standard deviations were below 0.9-8.8%.

TEL/ETV6 accelerates erythroid differentiation and inhibits megakaryocytic maturation in a human leukemia cell line UT-7/GM

TEL/ETV6 accelerates erythroid differentiation in the murine erythroleukemia cell line. To clarify the effects of TEL on megakaryocytic maturation as well as erythroid differentiation, we chose the human leukemia cell line UT-7/GM that differentiates into the erythroid and megakaryocytic lineages by treatment with erythropoietin and thrombopoietin, respectively. Upon erythropoietin exposure, overexpressed TEL stimulated hemoglobin synthesis and accumulation of the erythroid differentiation-specific transcripts such as gamma-globin, delta-aminolevulinic acid synthase-erythroid, and erythropoietin receptor. Moreover, the glycophorin A(+)/glycoprotein IIb(-) fraction appeared more rapidly in the TEL-overexpressing cells. Interestingly, overexpression of TEL was associated with lower levels of the megakaryocytic maturation-specific glycoprotein IIb and platelet factor 4 transcripts under the treatment with thrombopoietin. Consistently, the glycophorin A(-)/glycoprotein IIb(+) fraction increased more slowly in the TEL-overexpressing cells. Finally, expression of endogenous TEL proteins in UT-7/GM cells was down-regulated following erythropoietin and thrombopoietin exposure. All these data suggest that TEL may decide the fate of human erythrocyte/megakaryocyte common progenitors to differentiate towards the erythroid lineage and against the megakaryocytic lineage.

Dysplastic definitive hematopoiesis in AML1/EVI1 knock-in embryos

The AML1/EVI1 chimeric gene is created by the t(3;21)(q26;q22) chromosomal translocation seen in patients with leukemic transformation of myelodysplastic syndrome or blastic crisis of chronic myelogenous leukemia. We knocked-in the AML1/EVI1 chimeric gene into mouse Aml1 genomic locus to explore its effect in developmental hematopoiesis in vivo. AML1/EVI1/+ embryo showed defective hematopoiesis in the fetal liver and died around embryonic day 13.5 (E13.5) as a result of hemorrhage in the central nervous system. The peripheral blood had yolk-sac-derived nucleated erythroblasts but lacked erythrocytes of the definitive origin. Although E12.5 fetal liver contained progenitors for macrophage only, E13.5 fetal liver contained multilineage progenitors capable of differentiating into dysplastic myelocyte and megakaryocyte. No erythroid progenitor was detected in E12.5 or E13.5 fetal liver. Hematopoietic progenitors from E13.5 AML1/EVI1/+ fetal liver were highly capable of self-renewal compared with those from wild-type liver. Maintained expression of PU.1 gene and decreased expression of LMO2 and SCL genes may explain the aberrant hematopoiesis in AML1/EVI1/+ fetal liver.

Functional domains of Runx1 are differentially required for CD4 repression, TCRbeta expression, and CD4/8 double-negative to CD4/8 double-positive transition in thymocyte development

Runx1 (AML1) has multiple functions in thymocyte development, including CD4 repression in immature thymocytes, expression of TCRbeta, and efficient beta-selection. To determine the functional domains of Runx1 important for thymocyte development, we cultured Runx1-deficient murine fetal liver (FL) cells on OP9-Delta-like 1 murine stromal cells, which express Delta-like 1 and support thymocyte development in vitro, and introduced Runx1 or C-terminal-deletion mutants of Runx1 into the FL cells by retrovirus infection. In this system, Runx1-deficient FL cells failed to follow normal thymocyte development, whereas the introduction of Runx1 into the cells was sufficient to produce thymocyte development that was indistinguishable from that in wild-type FL cells. In contrast, Runx1 mutants that lacked the activation domain necessary for initiating gene transcription did not fully restore thymocyte differentiation, in that it neither repressed CD4 expression nor promoted the CD4/8 double-negative to CD4/8 double-positive transition. Although the C-terminal VWRPY motif-deficient mutant of Runx1, which cannot interact with the transcriptional corepressor Transducin-like enhancer of split (TLE), promoted the double-negative to double-positive transition, it did not efficiently repress CD4 expression. These results suggest that the activation domain is essential for Runx1 to establish thymocyte development and that Runx1 has both TLE-dependent and TLE-independent functions in thymocyte development.

Clinical diagnosis of MM2-type sporadic Creutzfeldt-Jakob disease

BACKGROUND

No method for the clinical diagnosis of MM2-type sporadic Creutzfeldt-Jakob disease (sCJD) has been established except for pathologic examination.

OBJECTIVE

To identify a reliable marker for the clinical diagnosis of MM2-type sCJD.

METHODS

CSF, EEG, and neuroimaging studies were performed in eight patients with MM2-type sCJD confirmed by neuropathologic, genetic, and western blot analyses.

RESULTS

The eight cases were pathologically classified into the cortical (n = 2), thalamic (n = 5), and combined (corticothalamic) (n = 1) forms. The cortical form was characterized by late-onset, slowly progressive dementia, cortical hyperintensity signals on diffusion-weighted imaging (DWI) of brain, and elevated levels of CSF 14-3-3 protein. The thalamic form showed various neurologic manifestations including dementia, ataxia, and pyramidal and extrapyramidal signs with onset at various ages and relatively long disease duration. Characteristic EEG and MRI abnormalities were almost absent. However, all four patients examined with cerebral blood flow (CBF) study using SPECT showed reduction of the CBF in the thalamus as well as the cerebral cortex. The combined form had features of both the cortical and the thalamic forms, showing cortical hyperintensity signals on DWI and hypometabolism of the thalamus on [18F]2-fluoro-2-deoxy-d-glucose PET.

CONCLUSION

For the clinical diagnosis of MM2-type sporadic Creutzfeldt-Jakob disease, cortical hyperintensity signals on diffusion-weighted MRI are useful for the cortical form and thalamic hypoperfusion or hypometabolism on cerebral blood flow SPECT or [18F]2-fluoro-2-deoxy-d-glucose PET for the thalamic form.

A Prospective Trial to Evaluate the Safety and Efficacy of Pravastatin for the Treatment of Refractory Chronic Graft-Versus-Host Disease

This prospective study evaluates the safety and efficacy of pravastatin for the treatment of chronic graft-versus-host disease (GVHD). We included 18 patients with refractory chronic GVHD. Oral pravastatin was started at 10 mg/day, and the dose was increased up to 40 mg/day in 4 weeks. This maximum dose was administered over 8 weeks. There were no severe adverse events caused by pravastatin. A clinical response was observed in the skin score in two patients, mouth score in five patients, eye score in two patients, liver score in three patients, platelet count score in one patient, and weight loss in two patients. The overall response rate was 28%. Immunophenotypic analyses showed that T-helper (Th)1 cells were dominant in all but one patient before treatment and that the Th1/Th2 ratio tended to be lower in the responders than in the nonresponders. A randomized controlled trial is warranted to evaluate the efficacy of pravastatin against chronic GVHD.

Vaccination with helper-dependent adenovirus enhances the generation of transgene-specific CTL

Recombinant adenoviral vectors (AdV) have been used experimentally as vaccines to present antigenic transgenes in vivo. However, administration of first-generation vectors (FG-AdV) is often limited by their induction of antiviral immunity. To address this limitation, helper-dependent vectors (HD-AdV) were developed that lack viral coding regions. While the administration of HD-AdV results in long-term gene expression in vivo, their utility as immunogens has never been examined. Direct vaccination with 10(8) blue-forming units (BFU) of HD-AdV injected into C57BL/6 mice lead to superior transgene-specific CTL and antibody responses when compared to the same amount of a FG-AdV. The antibody responses to viral antigens were high in response to both the vectors. As a mechanism to reduce viral exposure, dendritic cells (DC) were transduced with HD-AdV in vitro and then used as a cell-based vaccine. DC transduced with HD-AdV expressed higher levels of transgene-specific mRNA and up to 1200-fold higher levels of transgene protein than did DC transduced with a FG-AdV. In addition, HD-AdV-transduced DC stimulated superior transgene-specific CTL responses when administered in vivo, an effect that was further enhanced by maturing the DC with LPS prior to administration. In contrast to direct immunization with HD-AdV, vaccination with HD-AdV-transduced DC was associated with limited antibody responses against the AdV. We conclude that HD-AdV stimulates superior transgene-specific immune responses when compared to a FG-AdV, and that immunization with a DC-based vaccine maintains this efficacy while limiting antiviral reactivity.

The transcriptionally active form of AML1 is required for hematopoietic rescue of the AML1-deficient embryonic para-aortic splanchnopleural (P-Sp) region

Acute myelogenous leukemia 1 (AML1; runt-related transcription factor 1 [Runx1]) is a member of Runx transcription factors and is essential for definitive hematopoiesis. Although AML1 possesses several subdomains of defined biochemical functions, the physiologic relevance of each subdomain to hematopoietic development has been poorly understood. Recently, the consequence of carboxy-terminal truncation in AML1 was analyzed by the hematopoietic rescue assay of AML1-deficient mouse embryonic stem cells using the gene knock-in approach. Nonetheless, a role for specific internal domains, as well as for mutations found in a human disease, of AML1 remains to be elucidated. In this study, we established an experimental system to efficiently evaluate the hematopoietic potential of AML1 using a coculture system of the murine embryonic para-aortic splanchnopleural (P-Sp) region with a stromal cell line, OP9. In this system, the hematopoietic defect of AML1-deficient P-Sp can be rescued by expressing AML1 with retroviral infection. By analysis of AML1 mutants, we demonstrated that the hematopoietic potential of AML1 was closely related to its transcriptional activity. Furthermore, we showed that other Runx transcription factors, Runx2/AML3 or Runx3/AML2, could rescue the hematopoietic defect of AML1-deficient P-Sp. Thus, this experimental system will become a valuable tool to analyze the physiologic function and domain contribution of Runx proteins in hematopoiesis.

[Myelodysplastic syndrome associated with intestinal tract-type Behçet disease characterized by an esophageal ulcer]

A 55-year-old man with advanced myelodysplastic syndrome was hospitalized prior to undergoing an allogeneic bone marrow transplantation. Immediately before hospitalization, he had suffered from phlegmon in both lower extremities and right forearm as well as genital and oral ulcers. After admission, he developed an esophageal ulcer and was thus diagnosed as having intestinal tract-type Behçet disease. HLA-B51 was not present. Within a month, he died of pulmonary hemorrhage associated with pneumonia, possibly because of a low platelet count, and vasculoendothelial damage related to Behçet disease. This is a rare case of myelodysplastic syndrome that developed Behçet disease with a severe esophageal ulcer.

TEL/AML1 shows dominant-negative effects over TEL as well as AML1

The TEL/AML1 chimeric gene is generated by the t(12;21) translocation in pre-B cell acute lymphoblastic leukemia. TEL/AML1 consists of the helix-loop-helix (HLH) dimerization domain from TEL and almost the entire of AML1, but loses the ETS DNA-binding domain from TEL. Dominant-negative effects of TEL/AML1 over wild-type-AML1 are believed to trigger the development of this type of leukemia. However, it could also be possible that TEL/AML1 affects wild-type-TEL's molecular and tumor suppressive functions through the HLH domain. To test this possibility, we first confirmed that TEL/AML1 associates with wild-type-TEL. TEL/AML1 neither bound to the ETS-binding consensus site nor repressed transcription through it. Regardless, this prevented wild-type-TEL-induced transcriptional repression. Moreover, TEL/AML1 concomitantly inhibited wild-type-TEL-induced growth suppression and wild-type-AML1-mediated transforming activity in NIH3T3 cells. All these data indicate that TEL/AML1 exerts dominant-interfering effects on both AML1 and TEL, and that expression of TEL/AML1 could result in inactivation of TEL's tumor suppressive functions in t(12;21)-carrying leukemia.

Vestibular function and vasopressin

OBJECTIVE

To investigate the relation between the vestibular system and vasopressin (AVP).

MATERIAL AND METHODS

We examined the effects of electrical and caloric vestibular stimulation on plasma AVP levels in anesthetized rats. Plasma AVP levels of patients with intractable Ménière's disease who were subjected to endolymphatic drainage and steroid instillation surgery (EDSS) or intratympanic gentamicin (GM) injection were measured before and after these interventions.

RESULTS

Electrical vestibular stimulation increased plasma AVP levels in a current intensity-dependent manner. Plasma AVP levels were also increased by caloric stimulation with cold water. Plasma AVP levels decreased rapidly after EDSS, and were maintained at a low level even 6-12 months following EDSS or intratympanic GM injection.

CONCLUSIONS

Vestibular activation or inhibition-induced imbalance of intervestibular activities increased plasma AVP levels in rats. Therefore, vestibular disorder would seem to increase plasma AVP and thus worsen endolymphatic hydrops. EDSS rapidly decreased plasma AVP and would seem to reduce hydrops. Inhibition of vertigo spells by EDSS or intratympanic GM injection would reduce a possible stress response, resulting in a decrease in plasma AVP levels a long time after the treatments. This resultant decrease in AVP would beneficially inhibit the formation and/or maintenance of hydrops and thus prevent vertigo spells.

Midbrain hypometabolism as early diagnostic sign for progressive supranuclear palsy

OBJECTIVE

Progressive supranuclear palsy (PSP) is often misdiagnosed in early phase. The purpose of this study is to investigate the feature of [(18)F]fluoro-2-deoxy-d-glucose (FDG) positron emission tomography images for the early diagnosis of PSP.

METHODS

We studied 15 patients with PSP and 16 normal subjects. Using SPM99 and analysis of covariance to eliminate the effect of aging, the differences between PSP and normals were displayed as a statistical map. In the PSP, we also investigated the correlation with duration and with the subscores of Unified Parkinson's Disease Rating Scale.

RESULTS

The glucose metabolism of midbrain was significantly lower in PSP than in normals. However, correlation was not found between the metabolism of midbrain and clinical deterioration.

CONCLUSIONS

The statistical map clearly demonstrated the hypometabolism of midbrain in PSP, which is independent of the clinical deterioration. The hypometabolism of midbrain is one of the most promising sign for early diagnosis of PSP.

[Autologous peripheral blood stem cell transplantation for Japanese multiple myeloma patients: results of a feasibility study]

A feasibility study on high-dose therapy with autologous peripheral blood stem cell transplantation (HDT/PBSCT) was performed in Japanese patients with multiple myeloma (MM). Twenty evaluable patients younger than 65 years old with stage II/III MM were enrolled in this study. Three courses of VAD were used as initial chemotherapy. High-dose etoposide or cyclophosphamide followed by G-CSF was used for PBSCH, and 1.2-89.3 (median 23.4) x 106/kg of CD34+ cells were collected. Single (11 patients) or tandem (9 patients) HDT with melphalan (MEL) 200 mg/m2 or MEL 140 mg/m2 plus TBI 10 Gy were performed. The incidence of grade 4 toxicity (COG) was 10% and treatment-related mortality was 5%. Complete response and tumor reduction of more than 75% were obtained in 4 (21%) and 16 (84%) out of 19 patients, respectively. The actuarial 3-year overall survival (OS) and event-free survival (EFS) after PBSCT/HDT were 65.6% and 22.0%, respectively. The median EFS duration was 18 months. These preliminary results indicated that HDT/PBSCT is feasible for Japanese MM patients. A prospective randomized clinical trial will be required to assess the efficacy.

Molecular mechanisms of leukemogenesis by AML1/EVI-1

The AML1/EVI-1 chimeric gene is generated by the t(3;21)(q26;q22) translocation and plays a pivotal role in progression of hematopoietic stem cell malignancies such as chronic myelocytic leukemia and myelodysplastic syndrome. In AML1/EVI-1, an N-terminal half of AML1 including a runt homology domain is fused to the entire zinc-finger EVI-1 protein. AML1 is essential for hematopoietic cell development in fetal liver and its lineage-specific differentiation in adult. In contrast, EVI-1 is barely expressed in normal hematopoietic cells, but it is overexpressed in chronic myelocytic leukemia in blastic crisis and myelodysplastic syndrome-derived leukemia. There are at least four mechanisms identified in AML1/EVI-1 fusion protein that possibly lead into malignant transformation of hematopoietic stem cells. Firstly, AML1/EVI-1 exerts dominant-negative effects over AML1-induced transcriptional activation. Although target genes repressed by AML1/EVI-1 are still not known, binding competition to a specific DNA sequence and histone deacetylase recruitment through a co-repressor CtBP in EVI-1 part are conceivable underlying mechanisms for the dominant-negative effects. Secondly, AML1/EVI-1 interferes with TGF beta signaling and antagonizes the growth-inhibitory effects of TGF beta. The first zinc-finger domain of EVI-1 associates with Smad3, a TGF beta signal transducer, and represses its transcriptional activity by recruiting histone deacetylase through CtBP that interacts with EVI-1. Thirdly, AML1/EVI-1 blocks JNK activity and prevents stress-induced apoptosis. AML1/EVI-1 associates with JNK through the first zinc-finger domain of EVI-1 and disturbs the association between JNK and its substrates. Lastly, AML1/EVI-1 enhances AP-1 activity by activating the c-Fos promoter depending on the second zinc-finger domain of EVI-1, and promotes cell proliferation. All these functions cooperatively contribute to the malignant transformation of the hematopoietic stem cells by AML1/EVI-1.

Functional analysis of a dominant-negative DeltaETS TEL/ETV6 isoform

A transcriptional repressor TEL belongs to the ETS family transcription factors and acts as a tumor suppressor. We identified five alternatively spliced TEL isoforms generated possibly through exon skipping mechanisms, by using reverse transcriptase-polymerase chain reaction analysis. Among them, we examined molecular and biological functions of a DeltaETS-TEL isoform (TEL-f). This isoform abrogated specific DNA-binding capacity to and trans-repressional ability through the ETS-binding site. Regardless, it showed dominant-negative effects over wild-type-TEL (TEL-a)-mediated transcriptional repression partly through sequestration of TEL-a from nucleus to cytoplasm. Moreover, TEL-f dominantly interfered with TEL-a-mediated erythroid differentiation in MEL cells and growth suppression in NIH3T3 cells. Interestingly, TEL isoforms without the entire (Delta exons 6+7-TEL) or a part (Delta exon 7-TEL) of ETS domain were expressed more frequently in myelodysplastic syndrome-derived leukemia than in myelodysplastic syndrome before transformation. This observation suggests that accumulation of the dominant-negative DeltaETS-TEL molecules could be a related phenomenon to leukemic progression of myelodysplastic syndrome.