Assembly of Massive Galaxies in a High-z Protocluster

We present the results of wide-field deep JHK imaging of the SSA22 field using MOIRCS instrument equipped with Subaru telescope. The observed field is 112 arcmin^2 in area, which covers the z=3.1 protocluster characterized by the overdensities of Ly Alpha emitters (LAEs) and Ly Alpha Blobs (LABs). The 5 sigma limiting magnitude is K_{AB} = 24.3. We extract the potential protocluster members from the K-selected sample by using the multi-band photometric-redshift selection as well as the simple color cut for distant red galaxies (DRGs; J-K_{AB}>1.4). The surface number density of DRGs in our observed fields shows clear excess compared with those in the blank fields, and the location of the densest area whose projected overdensity is twice the average coincides with the large-scale density peak of LAEs. We also found that K-band counterparts with z_{phot} = 3.1 are detected for 75% (15/20) of the LABs within their Ly Alpha halo, and the 40 % (8/20) of LABs have multiple components, which gives a direct evidence of the hierarchical multiple merging in galaxy formation. The stellar mass ofLABs correlates with their luminosity, isophotal area, and the Ly Alpha velocity widths, implying that the physical scale and the dynamical motion of Ly Alpha emission are closely related to their previous star-formation activities. Highly dust-obscured galaxies such as hyper extremely red objects (HEROs; J-K_{AB}>2.1) and plausible K-band counterparts of submillimeter sources are also populated in the high density region.Comment: 21pages, accepted for publication in Astrophysical Journa

Subaru/MOIRCS Near-Infrared Imaging in the Proto-Cluster Region at z=3.1

We present the results of deep near-infrared imaging observations of the z=3.1 proto-cluster region in the SSA22a field taken by MOIRCS mounted on the Subaru Telescope. We observed a 21.7 arcmin^2 field to the depths of J=24.5, H=24.3, and K=23.9 (5 sigma). We examine the distribution of the K-selected galaxies at z~3 by using the simple color cut for distant red galaxies (DRGs) as well as the photometric-redshift selection technique. The marginal density excess of DRGs and the photo-z selected objects are found around the two most luminous Ly alpha blobs (LABs). We investigate the correlation between the K-selected objects and the LABs, and find that several galaxies with stellar mass M_* = 10^9-10^11 M_solar exist in vicinity of LABs, especially around the two most luminous ones. We also find that 7 of the 8 LABs in the field have plausible K_s-band counterparts and the sum of the stellar mass possibly associated with LABs correlates with the luminosity and surface brightness of them, which implies that the origin of Ly alpha emission may be closely correlated with their stellar mass or their previous star formation phenomena.Comment: 15 pages, 9 figures, accepted for publication in PASJ Vol.60, No.

Expression of OATP1B3 determines uptake of Gd-EOB-DTPA in hepatocellular carcinoma

Background: Gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid (Gd-EOB-DTPA) is an MRI contrast agent with perfusion and hepatoselective properties. The purpose of the study was to examine uptake of Gd-EOB-DTPA in the hepatobiliary phase in hepatocellular carcinoma (HCC). Methods: A retrospective analysis of 22 patients with HCC who underwent preoperative Gd-EOB-DTPA-enhanced MRI was performed. Enhancement ratios (ERs) and expression levels of the organic anion transporter (OATP) 1B3 protein were examined. Results: Gd-EOB-DTPA accumulated in the hepatobiliary phase in 6 of the 22 cases. All 6 Gd-EOB-DTPA-positive cases were moderately differentiated HCC, but 11 other moderately differentiated HCCs did not show Gd-EOB-DTPA uptake. Histopathologically, 4 Gd-EOB-DTPA-positive HCCs and 5 Gd-EOB-DTPA-negative HCCs produced bile. HCCs with Gd-EOB-DTPA uptake overexpressed OATP1B3 compared with HCCs without Gd-EOB-DTPA uptake, and OATP1B3 levels were significantly correlated with ERs (r = 0.91, P < 0.0001). Conclusions: Uptake of Gd-EOB-DTPA in HCC is determined by expression of OATP1B3 rather than by tumor differentiation or bile production

Increase of MZB1 in B cells in systemic lupus erythematosus: proteomic analysis of biopsied lymph nodes

Abstract Background Systemic lupus erythematosus (SLE) is a prototypical autoimmune disease in which dysregulation of B cells has been recognized. Here, we searched for potential biomarkers of SLE using liquid chromatography-tandem mass spectrometry (LC-MS). Methods Lymph nodes from SLE patients and controls were analyzed by LC-MS. To validate the identified molecules, immunoblotting and immunohistochemistry were performed and B cells from SLE patients were analyzed by quantitative RT-PCR. B-cell subsets from NZB/W F1 mice, which exhibit autoimmune disease resembling human SLE, were analyzed by flow cytometry. Endoplasmic reticulum (ER) stress was induced by tunicamycin and the serum concentration of anti-dsDNA antibodies was determined by ELISA. TUNEL methods and immunoblotting were used to assess the effect of tunicamycin. Results MZB1, which comprises part of a B-cell-specific ER chaperone complex and is a key player in antibody secretion, was one of the differentially expressed proteins identified by LC-MS and confirmed by immunoblotting. Immunohistochemically, larger numbers of MZB1+ cells were located mainly in interfollicular areas and scattered in germinal centers in specimens from SLE patients compared with those from controls. MZB1 colocalized with CD138+ plasma cells and IRTA1+ marginal zone B cells. MZB1 mRNA was increased by 2.1-fold in B cells of SLE patients with active disease (SLE Disease Activity Index 2000 ≥ 6) compared with controls. In aged NZB/W F1 mice, splenic marginal zone B cells and plasma cells showed elevated MZB1 levels. Tunicamycin induced apoptosis of MZB1+ cells in target organs, resulting in decreased serum anti-dsDNA antibody levels. Additionally, MZB1+ cells were increased in synovial tissue specimens from patients with rheumatoid arthritis. Conclusions MZB1 may be a potential therapeutic target in excessive antibody-secreting cells in SLE

Transgelin-2 is upregulated on activated B-cells and expressed in hyperplastic follicles in lupus erythematosus patients

<div><p>Transgelin-2 (TAGLN2) is an actin-binding protein that controls actin stability and promotes T cell activation. TAGLN2 is also expressed on B-cells but its function in B-cells is unknown. We found that TAGLN2-expressing B-cells were localized in the germinal center (GC) of secondary lymphoid tissues and <i>TAGLN2</i> mRNA was significantly upregulated after IgM+IgG stimulation in primary human B-cells, suggesting that TAGLN2 was upregulated upon B-cell activation. In support of this, lymph nodes (LNs) from patients with systemic lupus erythematosus (SLE), in which the intense GC activity have been recognized, showed increased TAGLN2 expression in B-cells compared to control LNs. Moreover, TAGLN2⁺B-cells were distributed widely not only in the GC but also in the perifollicular areas in SLE LNs. In contrast, CD19⁺ B-cells and CD19⁺CD27⁺ memory-B cells in peripheral blood of SLE patients showed no increase in TAGLN2 mRNA. Two-photon excitation microscopy of Raji cells demonstrated that TAGLN2 colocalized with F-actin and moved together to the periphery upon stimulation. <i>TAGLN2</i>-knockdown in Raji cells resulted in impaired phosphorylation of PLCγ2 leading to inhibition of cell migration. Microarray analysis of <i>TAGLN2</i>-knockdown Raji cells showed decreased expression of the genes associated with immune function including <i>CCR6</i> and as well as of those associated with regulation of the actin cytoskeleton including <i>ABI2</i>, compared to controls. These results suggest that TAGLN2 might regulate activation and migration of B-cells, in particular, the entry of activated B-cells into the follicle. We also suggest that TAGLN2 could be used as a marker for activated B-cells.</p></div

TAGLN2 colocalizes with F-actin and moves together to the periphery after stimulation. TAGLN2-GFP overlaps with LifeAct-RFP in Raji B cells at the outer actin ring.

<p>Raji cells co-transfected with TAGLN2-GFP and the actin probe LifeAct-RFP were stimulated with IgM+IgG, and the localization of each protein was then followed over the next 18 min using time lapse fluorescence microscopy. Top: TAGLN2-GFP (Green), middle: LifeAct-RFP (Magenta), bottom: merged image. The images marked as 0 were acquired before stimulation. Both the actin and TAGLN2 signals increased in intensity and thickness after IgM+IgG stimulation and were depleted from the central area of the cells and moved together to the periphery.</p

<i>TAGLN2</i> knockdown results in impaired phosphorylation of PLCγ, which is related to the actin-linked signaling pathway and inhibition of cell migration.

<p>(A) The total protein levels of PLCγ2, PI3K, ERK, and Akt and the levels of their phosphorylated forms after 10 min IgM+IgG stimulation of <i>TAGLN2</i>-knockdown (KD) Raji cells transfected with TAGLN2 siRNA, or of control cells with scrambled siRNA (Scramble), were detected by immunoblotting. Actin was blotted as a loading control. Suppression of TAGLN2 protein expression and PLCγ2 phosphorylation was seen in the <i>TAGLN2</i>-KD Raji cells compared with the scrambled siRNA transfected cells. (B) Normalized expression levels of each protein and each phosphorylated protein assessed using membrane densitometry. Three independent experiments were performed. *p<0.05. (C) Significant inhibition of CXCL13-dependent <i>TAGLN2</i> KD Raji cell chemotaxis as compared with negative controls. *p<0.05. RFU, relative fluorescence units. Migratory cells were lysed and quantified using fluorescent dye. The relative quantification was used to determine the change between various samples. Data were normalized by designating one sample in negative controls as equal to 1. Then, the ratiometric results were used to scale all values relative to that sample. (D) The CXCR5 and IgM expression levels were assessed by flow cytometry in <i>TAGLN2</i> KD and control Raji cells. <i>TAGLN2</i> KD appeared to have no effect on the surface expression of CXCR5 and IgM. Gray shading indicates isotype control.</p

Down-regulated genes related to the immune system.

<p>Down-regulated genes related to the immune system.</p

Pathway analysis of microarray data. Functional grouping of significant, differentially expressed down regulated genes in <i>TAGLN2</i> siRNA Raji cells versus the control (p<0.01).

<p>Pathway analysis of microarray data. Functional grouping of significant, differentially expressed down regulated genes in <i>TAGLN2</i> siRNA Raji cells versus the control (p<0.01).</p