Trogocytic molting of T cell microvilli upregulates T cell receptor surface expression and promotes clonal expansion.

Although T cell activation is known to involve the internalization of the T cell antigen receptor (TCR), much less is known regarding the release of TCRs following T cell interaction with cognate antigen-presenting cells. In this study, we examine the physiological mechanisms underlying TCR release following T cell activation. We show that T cell activation results in the shedding of TCRs in T cell microvilli, which involves a combined process of trogocytosis and enzymatic vesiculation, leading to the loss of membrane TCRs and microvilli-associated proteins and lipids. Surprisingly, unlike TCR internalization, this event results in the rapid upregulation of surface TCR expression and metabolic reprogramming of cholesterol and fatty acid synthesis to support cell division and survival. These results demonstrate that TCRs are lost through trogocytic 'molting' following T cell activation and highlight this mechanism as an important regulator of clonal expansion.

Silicon Wafer CMP Slurry Using a Hydrolysis Reaction Accelerator with an Amine Functional Group Remarkably Enhances Polishing Rate.

Recently, as an alternative solution for overcoming the scaling-down limitations of logic devices with design length of less than 3 nm and enhancing DRAM operation performance, 3D heterogeneous packaging technology has been intensively researched, essentially requiring Si wafer polishing at a very high Si polishing rate (500 nm/min) by accelerating the degree of the hydrolysis reaction (i.e., Si-O-H) on the polished Si wafer surface during CMP. Unlike conventional hydrolysis reaction accelerators (i.e., sodium hydroxide and potassium hydroxide), a novel hydrolysis reaction accelerator with amine functional groups (i.e., 552.8 nm/min for ethylenediamine) surprisingly presented an Si wafer polishing rate >3 times higher than that of conventional hydrolysis reaction accelerators (177.1 nm/min for sodium hydroxide). This remarkable enhancement of the Si wafer polishing rate for ethylenediamine was principally the result of (i) the increased hydrolysis reaction, (ii) the enhanced degree of adsorption of the CMP slurry on the polished Si wafer surface during CMP, and (iii) the decreased electrostatic repulsive force between colloidal silica abrasives and the Si wafer surface. A higher ethylenediamine concentration in the Si wafer CMP slurry led to a higher extent of hydrolysis reaction and degree of adsorption for the slurry and a lower electrostatic repulsive force; thus, a higher ethylenediamine concentration resulted in a higher Si wafer polishing rate. With the aim of achieving further improvements to the Si wafer polishing rates using Si wafer CMP slurry including ethylenediamine, the Si wafer polishing rate increased remarkably and root-squarely with the increasing ethylenediamine concentration.

T cell microvilli constitute immunological synaptosomes that carry messages to antigen-presenting cells.

Microvilli on T cells have been proposed to survey surfaces of antigen-presenting cells (APC) or facilitate adhesion under flow; however, whether they serve essential functions during T cell activation remains unclear. Here we show that antigen-specific T cells deposit membrane particles derived from microvilli onto the surface of cognate antigen-bearing APCs. Microvilli carry T cell receptors (TCR) at all stages of T cell activation and are released as large TCR-enriched, T cell microvilli particles (TMP) in a process of trogocytosis. These microvilli exclusively contain protein arrestin-domain-containing protein 1, which is directly involved in membrane budding and, in combination with vacuolar protein-sorting-associated protein 4, transforms large TMPs into smaller, exosome-sized TMPs. Notably, TMPs from CD4+ T cells are enriched with LFA-2/CD2 and various cytokines involved in activating dendritic cells. Collectively, these results demonstrate that T cell microvilli constitute "immunological synaptosomes" that carry T cell messages to APCs.

TAGLN2 polymerizes G-actin in a low ionic state but blocks Arp2/3-nucleated actin branching in physiological conditions.

TAGLN is an actin-binding protein family that comprises three isoforms with theorized roles in smooth muscle differentiation, tumour development, lymphocyte activation, and brain chemistry. However, their fundamental characteristics in regulation of the actin-based cytoskeleton are not fully understood. Here we show that TAGLN2 (including TAGLN1 and TAGLN3) extensively nucleates G-actin polymerization under low-salt conditions, where polymerization would be completely suppressed. The calponin homology domain and actin-binding loop are essential to mechanically connect two adjacent G-actins, thereby mediating multimeric interactions. However, TAGLN2 blocked the Arp2/3 complex binding to actin filaments under physiological salt conditions, thereby inhibiting branched actin nucleation. In HeLa and T cells, TAGLN2 enhanced filopodium-like membrane protrusion. Collectively, the dual functional nature of TAGLN2-G-actin polymerization and Arp2/3 complex inhibition-may account for the mechanisms of filopodia development at the edge of Arp2/3-rich lamellipodia in various cell types.

An Essential Role for TAGLN2 in Phagocytosis of Lipopolysaccharide-activated Macrophages.

Activated macrophages have a greater ability of phagocytosis against pathogens that is mediated by large-scale actin rearrangement. However, molecular machineries that conduct this task have not been fully identified. Here, we demonstrate an unanticipated role of TAGLN2, a 22-kDa actin-binding protein, in Toll-like receptor (TLR)-stimulated phagocytosis. TAGLN2 was greatly induced in macrophages in response to lipopolysaccharide (LPS), a ligand for TLR4, partly via the NF-κB pathway. TAGLN2-deficient macrophages (TAGLN2 -/-) showed defective phagocytic functions of IgM- and IgG-coated sheep red blood cells as well as bacteria. Cell signaling pathways involved in actin rearrangement-PI3 kinase/AKT and Ras-ERK-were also down-regulated in LPS-stimulated TAGLN2-deficient macrophages. Moreover, TAGLN2 -/- mice showed higher mortality after bacterial infection than wild-type littermates. Thus, our results revealed a novel function of TAGLN2 as a molecular armament required for host defense.

Electrochemiluminescent chemodosimeter based on iridium(III) complex for point-of-care detection of homocysteine levels.

Elevated levels of plasma homocysteine (Hcy) are an independent risk factor for cardiovascular disease. Although a routine, rapid, and simple determination of Hcy levels is highly desired, the existing methods are practically limited because of complicated sample preparation and bulky instrumentation. Herein, we report a chemodosimetric approach for one-step analysis of Hcy levels based on the electrochemiluminescence (ECL). A rationally designed cyclometalated iridium(III) complex possessing a phenylisoquinoline main ligand underwent a selective ring-formation reaction with Hcy to generate a binding adduct, which enabled producing highly luminescent excited states, and yielded strong ECL signals on the surface of electrode without any use of enzymes or antibodies. The level of Hcy was successfully monitored by the ECL increment with a linear correlation between 0 and 40µM in 99.9% aqueous media. The approach required neither sample preparation nor bulky instrument, suggesting the point-of-care testing of Hcy levels, and is potentially useful for routine, cost-effective, and precautionary diagnosis of various cardiovascular diseases.

Oral Administration of p-Hydroxycinnamic Acid Attenuates Atopic Dermatitis by Downregulating Th1 and Th2 Cytokine Production and Keratinocyte Activation.

Atopic dermatitis (AD) is a complex disease that is caused by various factors, including environmental change, genetic defects, and immune imbalance. We previously showed that p-hydroxycinnamic acid (HCA) isolated from the roots of Curcuma longa inhibits T-cell activation without inducing cell death. Here, we demonstrated that oral administration of HCA in a mouse model of ear AD attenuates the following local and systemic AD manifestations: ear thickening, immune-cell infiltration, production of AD-promoting immunoregulatory cytokines in ear tissues, increased spleen and draining lymph node size and weight, increased pro-inflammatory cytokine production by draining lymph nodes, and elevated serum immunoglobulin production. HCA treatment of CD4+ T cells in vitro suppressed their proliferation and differentiation into Th1 or Th2 and their Th1 and Th2 cytokine production. HCA treatment of keratinocytes lowered their production of the pro-inflammatory cytokines that drive either Th1 or Th2 responses in AD. Thus, HCA may be of therapeutic potential for AD as it acts by suppressing keratinocyte activation and downregulating T-cell differentiation and cytokine production.

Oral Administration of 4-Hydroxy-3-Methoxycinnamaldehyde Attenuates Atopic Dermatitis by Inhibiting T Cell and Keratinocyte Activation.

Atopic dermatitis (AD) is a skin condition caused by an imbalance of distinct subsets of T helper cells. Previously, we showed that 4-hydroxy-3-methoxycinnamaldehyde (4H3MC) inhibits T cell activation but does not induce apoptosis. Here, we examined the mechanism underlying the inhibitory effect of 4H3MC on AD both in vivo and in vitro. We sought to test the pharmacological effects of 4H3MC using a mouse model of 2, 4-'2,4-dinitrocholorobenzene' (DNCB)- and mite-induced AD. Also, we determined whether 4H3MC affects T cell differentiation and proliferation. Oral administration of 4H3MC attenuated the symptoms of DNCB- and mite-induced AD, including increased ear thickness, serum IgE levels, immune cell infiltration into inflammatory lesions, and pathogenic cytokine expression in ear tissues. In vitro, 4H3MC blocked T cell differentiation into Th1 and Th2 subtypes, as reflected by suppression of T-bet and GATA3, which are key transcription factors involved in T cell differentiation. In addition, 4H3MC downregulated T cell proliferation during Th1 and Th2 differentiation and keratinocyte activation. Collectively, these findings suggest that 4H3MC ameliorates AD symptoms by modulating the functions of effector T cells and keratinocytes.

Clinical application of sentinel lymph node biopsy based on axillary anatomy in breast cancer: A single institution experience.

BACKGROUND: Sentinel lymph node biopsy (SLNB), mostly with the use of vital dye or radioisotope, is a method for predicting axillary status in patients with breast cancer. Conventional axillary lymph node dissection (ALND) is used in cases where sentinel lymph node (SLN) is not detected by existing methods, but a series of studies have found that most of SLNs are present in specific anatomical spaces. We attempted to determine the feasibility of SLNB based on axillary anatomy in cases where SLN was not detected by conventional lymphatic mapping methods. METHODS: A retrospective analysis involving 208 patients who received anatomical SLNB between January 2003 and December 2010 was performed. Lateral border of the pectoralis major muscle and lateral thoracic vein were defined as the anatomical landmarks, and ALND was performed to at least level II, regardless of the results of frozen section analysis. Pathologic results were used to measure false negative rate and accuracy. Chi-square test and Fisher's exact test were performed to find factors affecting results. RESULTS: False negative rate and accuracy of anatomical SLNB were 21.7% (13/60) and 93.3% (182/195), respectively. T stage, clinical node status, number of dissected SLNs and body mass index were analyzed as factors affecting results, but none of them was found as having a statistically significant influence. CONCLUSION: These results suggest that anatomical SLNB may not replace ALND in cases where SLN is not detected by conventional lymphatic mapping method, but may be considered as a method for predicting axillary status before conducting a node dissection.

Regression of uveal melanoma after ru-106 brachytherapy and thermotherapy based on metabolic activity measured by positron emission tomography/computed tomography.

PURPOSE: To evaluate regression rates of uveal melanoma after combined Ru-106 plaque radiotherapy and thermotherapy according to metabolic activity measured by positron emission tomography/computed tomography imaging. METHODS: A retrospective medical chart review was conducted on 26 patients with uveal melanoma who underwent pretreatment whole-body positron emission tomography/computed tomography and received combined plaque radiotherapy and thermotherapy between 2006 and 2011. Tumors were classified as metabolically active and inactive based on the positron emission tomography/computed tomography imaging and compared with tumor height regression rates after treatment. RESULTS: Before treatment, the median tumor thickness was 8.8 mm for metabolically active tumors (7 eyes) and 5.0 mm for metabolically inactive tumors (19 eyes). The median tumor thicknesses with respect to the original thickness at 3, 6, and 12 months after treatment were 88%, 78%, and 64% for metabolically active tumors and 95%, 89%, and 81% for metabolically inactive tumors, respectively. The monthly tumor regression rates during the first 3 months (4.2% vs. 1.7%, P = 0.022) and the overall monthly tumor regression rates (3.0% vs. 1.5%, P = 0.041) were significantly higher for metabolically active tumors versus inactive tumors. Two patients with positive metabolic activity developed metastatic diseases 2 years after treatment, whereas no patient with negative metabolic activity developed metastatic disease during the study period. CONCLUSION: Positive metabolic activity of uveal melanoma based on the positron emission tomography/computed tomography was significantly associated with rapid initial tumor regression after combined plaque radiotherapy and thermotherapy, suggesting a prognostic value for this diagnostic approach.

Relationships between serum osteocalcin, leptin and the effect of weight loss by pharmacological treatment in healthy, nonsmoking Korean obese adults.

BACKGROUND: Recent studies have reported a relationship between osteocalcin (OC) levels and factors associated with energy metabolism and insulin resistance. As any detailed understanding of OC mechanisms still remains elusive, this study aimed at revealing a correlation between serum OC levels and obesity in healthy, nonsmoking, Korean obese adults who had undergone weight loss through pharmacological treatment. METHODS: 119 healthy, nonsmoking, Korean obese adults were investigated at 3 months following weight loss through pharmacological treatment. Serum OC, leptin, HOMA score, ghrelin, visceral fat mass, total body fat, and BMI were measured. RESULTS: Increase in serum OC was significantly associated with decreases in: BMI (and weight change %) (r=-0.209, p=0.023), visceral fat mass (r=-0.189, p=0.049), HOMA (r=-0.203 p=0.027), and leptin (r=-0.253 p=0.006), but not with changes in adiponectin (r=+0.029, p=NS), and Ghrelin (r=+0.019, p=NS). Decrease in leptin (ß=-0.280, p=0.002) was significantly associated with an increase in serum OC, after pharmacological weight loss treatment was adjusted for age, sex, drug type, and BMI (or visceral fat mass). CONCLUSIONS: Serum OC was significantly increased at 3 months after pharmacological weight loss. We further found that leptin levels were associated with changes in serum OC. These findings suggest a relationship between bone and adipose tissue.

Fluorescence turn-on probe for homocysteine and cysteine in water.

A simple fluorescent probe based on an ortho-hydroxy aldehyde-functionalized coumarin showed selective responses to homocysteine and cysteine by fluorescence turn-on.

Dimeric capsules with a nanoscale cavity for [60]fullerene encapsulation.

The acid-assisted and guest-induced formation of superstructures was achieved by the addition of haloacetic acids to a toluene solution of the resorcin[4]arene derivatives 1 and [60]fullerenes. The formation of dimeric superstructures that encapsulated a nanosized guest molecule was observed when appropriate acids, such as haloacetic acids, and suitable guest molecules, such as [60]fullerenes, were co-added to a toluene solution of cavitand 1 that has four pyridine units, whereas a complicated equilibrium between several species was detected without [60]fullerenes, and the formation of discrete superstructures was not monitored in the absence of haloacetic acids. The spectroscopic data indicate that the formed [60]fullerene-encapsulated complexes have the structure of 2. These complexes are self-assembled through pyridinium-anion-pyridinium interactions and by pi-pi and van der Waals interactions. The rate of decomplexation of 2 is estimated to be 3.1 s(-1) from a 2D exchange NMR spectrum. The [60]fullerene encapsulation process can be controlled by modifying the amounts of acids used, changing the temperature of the system, altering the ratio of acid/base, and even through varying the solvent polarity. Moreover, the fluorescence spectra show band-narrowing spectral changes and a retardation of the relaxation characteristics of isolated and isotropic [60]fullerenes, which indicates that the environmental change around [60]fullerene is induced upon its encapsulation.

Fluorescent chemodosimeter for selective detection of cyanide in water.

A coumarin-based fluorescent chemodosimeter with a salicylaldehyde functionality as a binding site has been developed for selective detection of cyanide anions over other anions in water at biological pH.