Cisd2 deficiency impairs neutrophil function by regulating calcium homeostasis via Calnexin and SERCA

In the context of aging, the susceptibility to infectious diseases increases, leading to heightened morbidity and mortality. This phenomenon, termed immunosenescence, is characterized by dysregulation in the aging immune system, including abnormal alterations in lymphocyte composition, elevated basal inflammation, and the accumulation of senescent T cells. Such changes contribute to increased autoimmune diseases, enhanced infection severity, and reduced responsiveness to vaccines. Utilizing aging animal models becomes imperative for a comprehensive understanding of immunosenescence, given the complexity of aging as a physiological process in living organisms. Our investigation focuses on Cisd2, a causative gene for Wolfram syndrome, to elucidate on immunosenescence. Cisd2 knockout (KO) mice, serving as a model for premature aging, exhibit a shortened lifespan with early onset of aging-related features, such as decreased bone density, hair loss, depigmentation, and optic nerve degeneration. Intriguingly, we found that the Cisd2 KO mice present a higher number of neutrophils in the blood; however, isolated neutrophils from these mice display functional defects. Through mass spectrometry analysis, we identified an interaction between Cisd2 and Calnexin, a protein known for its role in protein quality control. Beyond this function, Calnexin also regulates calcium homeostasis through interaction with sarcoendoplasmic reticulum calcium transport ATPase (SERCA). Our study proposes that Cisd2 modulates calcium homeostasis via its interaction with Calnexin and SERCA, consequently influencing neutrophil functions. [BMB Reports 2024; 57(5): 256-261].

Cellular Stress Responses against Coronavirus Infection: A Means of the Innate Antiviral Defense

Cellular stress responses are crucial for maintaining cellular homeostasis. Stress granules (SGs), activated by eIF2α kinases in response to various stimuli, play a pivotal role in dealing with diverse stress conditions. Viral infection, as one kind of cellular stress, triggers specific cellular programs aimed at overcoming virus-induced stresses. Recent studies have revealed that virus-derived stress responses are tightly linked to the host's antiviral innate immunity. Virus infection-induced SGs act as platforms for antiviral sensors, facilitating the initiation of protective antiviral responses called "antiviral stress granules" (avSGs). However, many viruses, including coronaviruses, have evolved strategies to suppress avSG formation, thereby counteracting the host's immune responses. This review discusses the intricate relationship between cellular stress responses and antiviral innate immunity, with a specific focus on coronaviruses. Furthermore, the diverse mechanisms employed by viruses to counteract avSGs are described.

SARS-CoV-2 variants with NSP12 P323L/G671S mutations display enhanced virus replication in ferret upper airways and higher transmissibility

With the emergence of multiple predominant SARS-CoV-2 variants, it becomes important to have a comprehensive assessment of their viral fitness and transmissibility. Here, we demonstrate that natural temperature differences between the upper (33°C) and lower (37°C) respiratory tract have profound effects on SARS-CoV-2 replication and transmissibility. Specifically, SARS-CoV-2 variants containing the NSP12 mutations P323L or P323L/G671S exhibit enhanced RNA-dependent RNA polymerase (RdRp) activity at 33°C compared with 37°C and high transmissibility. Molecular dynamics simulations and microscale thermophoresis demonstrate that the NSP12 P323L and P323L/G671S mutations stabilize the NSP12-NSP7-NSP8 complex through hydrophobic effects, leading to increased viral RdRp activity. Furthermore, competitive transmissibility assay reveals that reverse genetic (RG)-P323L or RG-P323L/G671S NSP12 outcompetes RG-WT (wild-type) NSP12 for replication in the upper respiratory tract, allowing markedly rapid transmissibility. This suggests that NSP12 P323L or P323L/G671S mutation of SARS-CoV-2 is associated with increased RdRp complex stability and enzymatic activity, promoting efficient transmissibility.

Lung-specific MCEMP1 functions as an adaptor for KIT to promote SCF-mediated mast cell proliferation

Lung mast cells are important in host defense, and excessive proliferation or activation of these cells can cause chronic inflammatory disorders like asthma. Two parallel pathways induced by KIT-stem cell factor (SCF) and FcεRI-immunoglobulin E interactions are critical for the proliferation and activation of mast cells, respectively. Here, we report that mast cell-expressed membrane protein1 (MCEMP1), a lung-specific surface protein, functions as an adaptor for KIT, which promotes SCF-mediated mast cell proliferation. MCEMP1 elicits intracellular signaling through its cytoplasmic immunoreceptor tyrosine-based activation motif and forms a complex with KIT to enhance its autophosphorylation and activation. Consequently, MCEMP1 deficiency impairs SCF-induced peritoneal mast cell proliferation in vitro and lung mast cell expansion in vivo. Mcemp1-deficient mice exhibit reduced airway inflammation and lung impairment in chronic asthma mouse models. This study shows lung-specific MCEMP1 as an adaptor for KIT to facilitate SCF-mediated mast cell proliferation.

OASL phase condensation induces amyloid-like fibrillation of RIPK3 to promote virus-induced necroptosis

RIPK3-ZBP1-MLKL-mediated necroptosis is a proinflammatory cell death process that is crucial for antiviral host defence. RIPK3 self-oligomerization and autophosphorylation are prerequisites for executing necroptosis, yet the underlying mechanism of virus-induced RIPK3 activation remains elusive. Interferon-inducible 2'-5' oligoadenylate synthetase-like (OASL) protein is devoid of enzymatic function but displays potent antiviral activity. Here we describe a role of OASL as a virus-induced necroptosis promoter that scaffolds the RIPK3-ZBP1 non-canonical necrosome via liquid-like phase condensation. This liquid-like platform of OASL recruits RIPK3 and ZBP1 via protein-protein interactions to provide spatial segregation for RIPK3 nucleation. This process facilitates the amyloid-like fibril formation and activation of RIPK3 and thereby MLKL phosphorylation for necroptosis. Mice deficient in Oasl1 exhibit severely impaired necroptosis and attenuated inflammation after viral infection, resulting in uncontrolled viral dissemination and lethality. Our study demonstrates an interferon-induced innate response whereby OASL scaffolds RIPK3-ZBP1 assembly via its phase-separated liquid droplets to facilitate necroptosis-mediated antiviral immunity.

SARS-CoV-2 variants show temperature-dependent enhanced polymerase activity in the upper respiratory tract and high transmissibility

With the convergent global emergence of SARS-CoV-2 variants of concern (VOC), a precise comparison study of viral fitness and transmission characteristics is necessary for the prediction of dominant VOCs and the development of suitable countermeasures. While airway temperature plays important roles in the fitness and transmissibility of respiratory tract viruses, it has not been well studied with SARS-CoV-2. Here we demonstrate that natural temperature differences between the upper (33°C) and lower (37°C) respiratory tract have profound effects on SARS-CoV-2 replication and transmission. Specifically, SARS-COV-2 variants containing the P323L or P323L/G671S mutation in the NSP12 RNA-dependent RNA polymerase (RdRp) exhibited enhanced RdRp enzymatic activity at 33°C compared to 37°C and high transmissibility in ferrets. MicroScale Thermophoresis demonstrated that the NSP12 P323L or P323L/G671S mutation stabilized the NSP12-NSP7-NSP8 complex interaction. Furthermore, reverse genetics-derived SARS-CoV-2 variants containing the NSP12 P323L or P323L/G671S mutation displayed enhanced replication at 33°C, and high transmission in ferrets. This suggests that the evolutionarily forced NSP12 P323L and P323L/G671S mutations of recent SARS-CoV-2 VOC strains are associated with increases of the RdRp complex stability and enzymatic activity, promoting the high transmissibility.

Enhanced antibody responses in fully vaccinated individuals against pan-SARS-CoV-2 variants following Omicron breakthrough infection

Omicron has become the globally dominant severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variant, creating additional challenges due to its ability to evade neutralization. Here, we report that neutralizing antibodies against Omicron variants are undetected following COVID-19 infection with ancestral or past SARS-CoV-2 variant viruses or after two-dose mRNA vaccination. Compared with two-dose vaccination, a three-dose vaccination course induces broad neutralizing antibody responses with improved durability against different SARS-CoV-2 variants, although neutralizing antibody titers against Omicron remain low. Intriguingly, among individuals with three-dose vaccination, Omicron breakthrough infection substantially augments serum neutralizing activity against a broad spectrum of SARS-CoV-2 variants, including Omicron variants BA.1, BA.2, and BA.5. Additionally, after Omicron breakthrough infection, memory T cells respond to the spike proteins of both ancestral and Omicron SARS-CoV-2 by producing cytokines with polyfunctionality. These results suggest that Omicron breakthrough infection following three-dose mRNA vaccination induces pan-SARS-CoV-2 immunity that may protect against emerging SARS-CoV-2 variants of concern.

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Early SARS-CoV-2 variant infections do not elicit NAbs against Omicron variants

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Three-dose vaccination induces broad, but variant-specific, NAbs against SARS-CoV-2

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Omicron breakthrough infection elicits pan-SARS-CoV-2 humoral immunity

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T cell immunity dose not differ upon stimulation with ancestral or Omicron spike

Inhibition of a broad range of SARS-CoV-2 variants by antiviral phytochemicals in hACE2 mice

Although several vaccines and antiviral drugs against SARS-CoV-2 are currently available, control and prevention of COVID-19 through these interventions is limited due to inaccessibility and economic issues in some regions and countries. Moreover, incomplete viral clearance by ineffective therapeutics may lead to rapid genetic evolution, resulting in the emergence of new SARS-CoV-2 variants that may escape the host immune system as well as currently available COVID-19 vaccines. Here, we report that phytochemicals extracted from Chlorella spp. and Psidium guajava possess broad-spectrum antiviral activity against a range of SARS-CoV-2 variants. Through chromatography-based screening, we identified four bioactive compounds and subsequently demonstrated their potential antiviral activities in vivo. Interestingly, in hACE2 mice, treatment with these compounds significantly attenuates SARS-CoV-2-induced proinflammatory responses, demonstrating their potential anti-inflammatory activity. Collectively, our study suggests that phytochemicals from edible plants may be readily available therapeutics and prophylactics against multiple SARS-CoV-2 strains and variants.

Innate immune sensing of coronavirus and viral evasion strategies

The innate immune system is the first line of the host defense program against pathogens and harmful substances. Antiviral innate immune responses can be triggered by multiple cellular receptors sensing viral components. The activated innate immune system produces interferons (IFNs) and cytokines that perform antiviral functions to eliminate invading viruses. Coronaviruses are single-stranded, positive-sense RNA viruses that have a broad range of animal hosts. Coronaviruses have evolved multiple means to evade host antiviral immune responses. Successful immune evasion by coronaviruses may enable the viruses to adapt to multiple species of host organisms. Coronavirus transmission from zoonotic hosts to humans has caused serious illnesses, such as severe acute respiratory syndrome (SARS), Middle East respiratory syndrome (MERS), and coronavirus disease-2019 (COVID-19), resulting in global health and economic crises. In this review, we summarize the current knowledge of the mechanisms underlying host sensing of and innate immune responses against coronavirus invasion, as well as host immune evasion strategies of coronaviruses.

Understanding how the innate immune system senses coronaviruses and how coronaviruses can escape detection could provide novel approaches to tackle infections. Coronaviruses, including SARS-CoV-2, constantly evolve to manipulate, obstruct and evade host immune responses. A team led by Ji-Seung Yoo, Hokkaido University, Sapporo, Japan, reviewed understanding of innate immune responses to coronaviruses and viral evasion strategies. Two major receptor families recognise RNA viruses upon infection, but how they respond to SARS-CoV-2 is unclear. One receptor, TLR7, plays a critical role in sensing coronavirus infections, and mutations in the TLR7 gene are associated with severe illness and mortality in young Covid-19 patients. Activating host TLR pathways may prove a useful therapeutic approach. Further in-depth investigations are needed into specific coronavirus proteins and viral mechanisms that suppress host immunity.

MHC class I transactivator NLRC5 in host immunity, cancer and beyond

The presentation of antigenic peptides by major histocompatibility complex (MHC) class I and class II molecules is crucial for activation of the adaptive immune system. The nucleotide-binding domain and leucine-rich repeat receptor family members CIITA and NLRC5 function as the major transcriptional activators of MHC class II and class I gene expression, respectively. Since the identification of NLRC5 as the master regulator of MHC class I and class-I-related genes, there have been major advances in understanding the function of NLRC5 in infectious diseases and cancer. Here, we discuss the biological significance and mechanism of NLRC5-dependent MHC class I expression.

Tannic Acid Inhibits Non-small Cell Lung Cancer (NSCLC) Stemness by Inducing G0/G1 Cell Cycle Arrest and Intrinsic Apoptosis

BACKGROUND/AIM

Non-small cell lung cancer (NSCLC) is one among the most common cancers worldwide. Recently, dietary phytochemicals have been reported as an attractive approach to improve the symptoms of NSCLC patients. Tannic acid is a natural polyphenol, which is known to have anticancer effects on in vitro models of breast, gingival and colon cancer. However, the molecular mechanisms associated with the actions of tannic acid on A549 human lung cancer cells have not been elucidated.

MATERIALS AND METHODS

In this study, we analyzed the effect of tannic acid on A549 cells and their underlying mechanisms using western blotting, flow cytometry, invasion assay and tumorsphere formation assay.

RESULTS

Tannic acid treatment suppressed the viability of A549 cells through cell cycle arrest and induction of the intrinsic pathways of apoptosis. In addition, the various malignant phenotypes of A549 cells including invasion, migration, and stemness were inhibited by tannic acid treatment.

CONCLUSION

Tannic acid could be used as an effective inhibitor of lung cancer progression.

Oncogenic human herpesvirus hijacks proline metabolism for tumorigenesis

Three-dimensional (3D) cell culture is well documented to regain intrinsic metabolic properties and to better mimic the in vivo situation than two-dimensional (2D) cell culture. Particularly, proline metabolism is critical for tumorigenesis since pyrroline-5-carboxylate (P5C) reductase (PYCR/P5CR) is highly expressed in various tumors and its enzymatic activity is essential for in vitro 3D tumor cell growth and in vivo tumorigenesis. PYCR converts the P5C intermediate to proline as a biosynthesis pathway, whereas proline dehydrogenase (PRODH) breaks down proline to P5C as a degradation pathway. Intriguingly, expressions of proline biosynthesis PYCR gene and proline degradation PRODH gene are up-regulated directly by c-Myc oncoprotein and p53 tumor suppressor, respectively, suggesting that the proline-P5C metabolic axis is a key checkpoint for tumor cell growth. Here, we report a metabolic reprogramming of 3D tumor cell growth by oncogenic Kaposi's sarcoma-associated herpesvirus (KSHV), an etiological agent of Kaposi's sarcoma and primary effusion lymphoma. Metabolomic analyses revealed that KSHV infection increased nonessential amino acid metabolites, specifically proline, in 3D culture, not in 2D culture. Strikingly, the KSHV K1 oncoprotein interacted with and activated PYCR enzyme, increasing intracellular proline concentration. Consequently, the K1-PYCR interaction promoted tumor cell growth in 3D spheroid culture and tumorigenesis in nude mice. In contrast, depletion of PYCR expression markedly abrogated K1-induced tumor cell growth in 3D culture, not in 2D culture. This study demonstrates that an increase of proline biosynthesis induced by K1-PYCR interaction is critical for KSHV-mediated transformation in in vitro 3D culture condition and in vivo tumorigenesis.

The Inhibitory Mechanisms of Tumor PD-L1 Expression by Natural Bioactive Gallic Acid in Non-Small-Cell Lung Cancer (NSCLC) Cells

Non-small-cell lung cancer (NSCLC) is the most common lung cancer subtype and accounts for more than 80% of all lung cancer cases. Epidermal growth factor receptor (EGFR) phosphorylation by binding growth factors such as EGF activates downstream prooncogenic signaling pathways including KRAS-ERK, JAK-STAT, and PI3K-AKT. These pathways promote the tumor progression of NSCLC by inducing uncontrolled cell cycle, proliferation, migration, and programmed death-ligand 1 (PD-L1) expression. New cytotoxic drugs have facilitated considerable progress in NSCLC treatment, but side effects are still a significant cause of mortality. Gallic acid (3,4,5-trihydroxybenzoic acid; GA) is a phenolic natural compound, isolated from plant derivatives, that has been reported to show anticancer effects. We demonstrated the tumor-suppressive effect of GA, which induced the decrease of PD-L1 expression through binding to EGFR in NSCLC. This binding inhibited the phosphorylation of EGFR, subsequently inducing the inhibition of PI3K and AKT phosphorylation, which triggered the activation of p53. The p53-dependent upregulation of miR-34a induced PD-L1 downregulation. Further, we revealed the combination effect of GA and anti-PD-1 monoclonal antibody in an NSCLC-cell and peripheral blood mononuclear-cell coculture system. We propose a novel therapeutic application of GA for immunotherapy and chemotherapy in NSCLC.

Tannic Acid Promotes TRAIL-Induced Extrinsic Apoptosis by Regulating Mitochondrial ROS in Human Embryonic Carcinoma Cells

: Human embryonic carcinoma (EC; NCCIT) cells have self-renewal ability and pluripotency. Cancer stem cell markers are highly expressed in NCCIT cells, imparting them with the pluripotent nature to differentiate into other cancer types, including breast cancer. As one of the main cancer stem cell pathways, Wnt/β-catenin is also overexpressed in NCCIT cells. Thus, inhibition of these pathways defines the ability of a drug to target cancer stem cells. Tannic acid (TA) is a natural polyphenol present in foods, fruits, and vegetables that has anti-cancer activity. Through Western blotting and PCR, we demonstrate that TA inhibits cancer stem cell markers and the Wnt/β-catenin signaling pathway in NCCIT cells and through a fluorescence-activated cell sorting analysis we demonstrated that TA induces sub-G1 cell cycle arrest and apoptosis. The mechanism underlying this is the induction of mitochondrial reactive oxygen species (ROS) (mROS), which then induce the tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-mediated extrinsic apoptosis pathway instead of intrinsic mitochondrial apoptosis pathway. Moreover, ribonucleic acid sequencing data with TA in NCCIT cells show an elevation in TRAIL-induced extrinsic apoptosis, which we confirm by Western blotting and real-time PCR. The induction of human TRAIL also proves that TA can induce extrinsic apoptosis in NCCIT cells by regulating mROS.

The Cap-Snatching SFTSV Endonuclease Domain Is an Antiviral Target

Severe fever with thrombocytopenia syndrome virus (SFTSV) is a tick-borne virus with 12%-30% case mortality rates and is related to the Heartland virus (HRTV) identified in the United States. Together, SFTSV and HRTV are emerging segmented, negative-sense RNA viral (sNSV) pathogens with potential global health impact. Here, we characterize the amino-terminal cap-snatching endonuclease domain of SFTSV polymerase (L) and solve a 2.4-Å X-ray crystal structure. While the overall structure is similar to those of other cap-snatching sNSV endonucleases, differences near the C terminus of the SFTSV endonuclease suggest divergence in regulation. Influenza virus endonuclease inhibitors, including the US Food and Drug Administration (FDA) approved Baloxavir (BXA), inhibit the endonuclease activity in in vitro enzymatic assays and in cell-based studies. BXA displays potent activity with a half maximal inhibitory concentration (IC50) of ∼100 nM in enzyme inhibition and an EC50 value of ∼250 nM against SFTSV and HRTV in plaque assays. Together, our data support sNSV endonucleases as an antiviral target.

Efficient Inhibition of Human Papillomavirus Infection by L2 Minor Capsid-Derived Lipopeptide

The amino (N)-terminal region of human papillomavirus (HPV) minor capsid protein (L2) is a highly conserved region which is essential for establishing viral infection. Despite its importance in viral infectivity, the role of the HPV N-terminal domain has yet to be fully characterized. Using fine mapping analysis, we identified a 36-amino-acid (aa) peptide sequence of the L2 N terminus, termed L2N, that is critical for HPV infection. Ectopic expression of L2N with the transmembrane sequence on the target cell surface conferred resistance to HPV infection. Additionally, L2N peptide with chemical or enzymatic lipidation at the carboxyl (C) terminus efficiently abrogated HPV infection in target cells. Among the synthetic L2N lipopeptides, a stearoylated lipopeptide spanning aa 13 to 46 (13-46st) exhibited the most potent anti-HPV activity, with a half-maximal inhibitory concentration (IC50) of ∼200 pM. Furthermore, we demonstrated that the 13-46st lipopeptide inhibited HPV entry by blocking trans-Golgi network retrograde trafficking of virion particles, leading to rapid degradation. Fundamentally, the inhibitory effect of L2N lipopeptides appeared to be evolutionarily conserved, as they showed cross-type inhibition among various papillomaviruses. In conclusion, our findings provide new insights into the critical role of the L2N sequence in the HPV entry mechanism and identify the therapeutic potential of L2N lipopeptide as an effective anti-HPV agent.IMPORTANCE HPV is a human oncogenic virus that causes a major public health problem worldwide, which is responsible for approximately 5% of total human cancers and almost all cases of cervical cancers. HPV capsid consists of two structure proteins, the major capsid L1 protein and the minor capsid L2 protein. While L2 plays critical roles during the viral life cycle, the molecular mechanism in viral entry remains elusive. Here, we performed fine mapping of the L2 N-terminal region and defined a short 36-amino-acid peptide, called L2N, which is critical for HPV infection. Specifically, L2N peptide with carboxyl-terminal lipidation acted as a potent and cross-type HPV inhibitor. Taken together, data from our study highlight the essential role of the L2N sequence at the early step of HPV entry and suggests the L2N lipopeptide as a new strategy to broadly prevent HPV infection.

Nutrient ileal digestibility evaluation of dried mealworm (Tenebrio molitor) larvae compared to three animal protein by-products in growing pigs

Objective

This study was to investigate the nutrient ileal digestibility of dried mealworm (Tenebrio molitor) larvae and compare with those of three animal protein by-products in growing pigs.

Methods

A total of 12 crossbred ([Landrace×Yorkshire]×Duroc) growing pigs with average body weights of 24.12±0.68 kg were surgically equipped with simple T-cannulas after being deprived of feed for 24 h according to published surgical procedures. These pigs had a recovery period of two weeks. A total of 12 pigs were assigned to individual metabolic crates and allotted to one of four treatments with 3 replicates in a fully randomized design. Dietary treatments included the following: i) Fish meal, corn-vegetable by-product basal diet+9.95% fish meal; ii) Meat meal, corn-vegetable by-product basal diet+9.95% meat meal; iii) Poultry meal, corn-vegetable by-product basal diet+9.95% poultry meal; iv) Tenebrio molitor, corn-vegetable by-product basal diet+9.95% dried Tenebrio molitor larvae.

Results

Results showed that the apparent ileal digestibility (AID) of Lys was higher (p<0.05) in pigs fed Tenebrio molitor diet than that in pigs fed fish meal diet. Pigs fed Tenebrio molitor diet showed increased (p<0.05) AID of His and Arg compared to pigs fed Fish meal or Meat meal diet. The AID of Cys was increased (p<0.05) in pigs fed poultry meal and Tenebrio molitor diets compared to that in pigs fish meal diet. Pigs fed meat meal, poultry meal, and Tenebrio molitor diets showed higher (p<0.05) standardized ileal digestibility (SID) of total energy compared to pigs fed fish meal diet. The SID of Arg was higher (p<0.05) in pigs fed Tenebrio molitor diet than that in pigs fed fish meal or meat meal diet. Furthermore, pigs fed poultry meal or Tenebrio molitor diets showed increased (p<0.05) SID of Cys compared to pigs fed fish meal diet.

Conclusion

In conclusion, providing pigs with diets that contained Tenebrio molitor larvae meal improved AID and SID of nutrients as well as essential and non-essential amino acids. The digestibility of dried mealworm larvae protein and its utilization in vivo are also good. Therefore, dried mealworm larvae protein can be used as protein source at 10% level in growing pigs.

Variations in fat mass contribution to bone mineral density by gender, age, and body mass index: the Korea National Health and Nutrition Examination Survey (KNHANES) 2008-2011

The relationship of body composition and bone mineral density is complex and controversial. When classifying Korean population based on gender, age, and body mass index, fat mass had varying contributions to bone mineral density.

INTRODUCTION

The relationship between body composition and bone mineral density (BMD) is complex, and it is uncertain how components of body mass variably affect BMD.

METHODS

This cross-sectional observational study was performed in subjects ≥20 years based on the Korea National Health and Nutrition Examination Survey (KNHANES) 2008 to 2011. Among 17,583 subjects, the mean ages were 49.1 ± 16.0 years (M, n = 7495) and 49.3 ± 16.3 years (F, n = 10,088). Subjects were divided into age groups, either <50 or ≥50 years for males, or menopausal state, either premenopausal or postmenopausal, for females. A further classification used BMI, either <25 or ≥25 kg/m(2). Anthropometric and body composition parameters were compared and evaluated to look for correlations with BMD. Further, appendicular lean mass (ALM), fat mass (FM), fat percentage (FP), and waist circumference (WC) were included for multivariate analysis with BMD, controlling for covariates in each age group and BMI subgroup.

RESULTS

Anthropometric and body composition parameters significantly correlated with BMD in all age groups for both genders. After adjusting for covariates, ALM strongly affected BMD in all age groups for both genders. FM, FP, and WC significantly affected BMD in both age groups of women and in older men, but they did not affect BMD in younger men. Fat indices positively affected BMD of all sites in all non-obese women and in non-obese older men. However, little contribution was found in obese subgroups of both genders and in non-obese younger men.

CONCLUSION

Considering different weights of covariates, ALM strongly contributed to BMD in all gender, age, and BMI groups. On the other hand, fat indices positively affected BMD of both age groups in women and older men with normal BMI, but they showed little contribution to BMD within the same age groups with high BMI or any BMI subgroups of younger men.

Measurements of Elliptic and Triangular Flow in High-Multiplicity 3He+Au Collisions at √(s(NN))=200 GeV

We present the first measurement of elliptic (v(2)) and triangular (v(3)) flow in high-multiplicity (3)He+Au collisions at √(s(NN))=200  GeV. Two-particle correlations, where the particles have a large separation in pseudorapidity, are compared in (3)He+Au and in p+p collisions and indicate that collective effects dominate the second and third Fourier components for the correlations observed in the (3)He+Au system. The collective behavior is quantified in terms of elliptic v(2) and triangular v(3) anisotropy coefficients measured with respect to their corresponding event planes. The v(2) values are comparable to those previously measured in d+Au collisions at the same nucleon-nucleon center-of-mass energy. Comparisons with various theoretical predictions are made, including to models where the hot spots created by the impact of the three (3)He nucleons on the Au nucleus expand hydrodynamically to generate the triangular flow. The agreement of these models with data may indicate the formation of low-viscosity quark-gluon plasma even in these small collision systems.

Measurement of Long-Range Angular Correlation and Quadrupole Anisotropy of Pions and (Anti)Protons in Central d+Au Collisions at sqrt[s_{NN}]=200 GeV

We present azimuthal angular correlations between charged hadrons and energy deposited in calorimeter towers in central d+Au and minimum bias p+p collisions at sqrt[s_{NN}]=200 GeV. The charged hadron is measured at midrapidity |η|<0.35, and the energy is measured at large rapidity (-3.7<η<-3.1, Au-going direction). An enhanced near-side angular correlation across |Δη|>2.75 is observed in d+Au collisions. Using the event plane method applied to the Au-going energy distribution, we extract the anisotropy strength v_{2} for inclusive charged hadrons at midrapidity up to p_{T}=4.5 GeV/c. We also present the measurement of v_{2} for identified π^{±} and (anti)protons in central d+Au collisions, and observe a mass-ordering pattern similar to that seen in heavy-ion collisions. These results are compared with viscous hydrodynamic calculations and measurements from p+Pb at sqrt[s_{NN}]=5.02 TeV. The magnitude of the mass ordering in d+Au is found to be smaller than that in p+Pb collisions, which may indicate smaller radial flow in lower energy d+Au collisions.

Cold-nuclear-matter effects on heavy-quark production at forward and backward rapidity in d + Au collisions at √sNN = 200 GeV

The PHENIX experiment has measured open heavy-flavor production via semileptonic decay over the transverse momentum range 1 < p(T) < 6  GeV/c at forward and backward rapidity (1.4 < |y| < 2.0) in d+Au and p + p collisions at √sNN = 200  GeV. In central d+Au collisions, relative to the yield in p + p collisions scaled by the number of binary nucleon-nucleon collisions, a suppression is observed at forward rapidity (in the d-going direction) and an enhancement at backward rapidity (in the Au-going direction). Predictions using nuclear-modified-parton-distribution functions, even with additional nuclear-p(T) broadening, cannot simultaneously reproduce the data at both rapidity ranges, which implies that these models are incomplete and suggests the possible importance of final-state interactions in the asymmetric d + Au collision system. These results can be used to probe cold-nuclear-matter effects, which may significantly affect heavy-quark production, in addition to helping constrain the magnitude of charmonia-breakup effects in nuclear matter.

DHX36 enhances RIG-I signaling by facilitating PKR-mediated antiviral stress granule formation

RIG-I is a DExD/H-box RNA helicase and functions as a critical cytoplasmic sensor for RNA viruses to initiate antiviral interferon (IFN) responses. Here we demonstrate that another DExD/H-box RNA helicase DHX36 is a key molecule for RIG-I signaling by regulating double-stranded RNA (dsRNA)-dependent protein kinase (PKR) activation, which has been shown to be essential for the formation of antiviral stress granule (avSG). We found that DHX36 and PKR form a complex in a dsRNA-dependent manner. By forming this complex, DHX36 facilitates dsRNA binding and phosphorylation of PKR through its ATPase/helicase activity. Using DHX36 KO-inducible MEF cells, we demonstrated that DHX36 deficient cells showed defect in IFN production and higher susceptibility in RNA virus infection, indicating the physiological importance of this complex in host defense. In summary, we identify a novel function of DHX36 as a critical regulator of PKR-dependent avSG to facilitate viral RNA recognition by RIG-I-like receptor (RLR).

Critical role of an antiviral stress granule containing RIG-I and PKR in viral detection and innate immunity

Retinoic acid inducible gene I (RIG-I)-like receptors (RLRs) function as cytoplasmic sensors for viral RNA to initiate antiviral responses including type I interferon (IFN) production. It has been unclear how RIG-I encounters and senses viral RNA. To address this issue, we examined intracellular localization of RIG-I in response to viral infection using newly generated anti-RIG-I antibody. Immunohistochemical analysis revealed that RLRs localized in virus-induced granules containing stress granule (SG) markers together with viral RNA and antiviral proteins. Because of similarity in morphology and components, we termed these aggregates antiviral stress granules (avSGs). Influenza A virus (IAV) deficient in non-structural protein 1 (NS1) efficiently generated avSGs as well as IFN, however IAV encoding NS1 produced little. Inhibition of avSGs formation by removal of either the SG component or double-stranded RNA (dsRNA)-dependent protein kinase (PKR) resulted in diminished IFN production and concomitant enhancement of viral replication. Furthermore, we observed that transfection of dsRNA resulted in IFN production in an avSGs-dependent manner. These results strongly suggest that the avSG is the locus for non-self RNA sensing and the orchestration of multiple proteins is critical in the triggering of antiviral responses.

Cross section and parity-violating spin asymmetries of W± boson production in polarized p + p collisions at sqrt[s] = 500 GeV

Large parity-violating longitudinal single-spin asymmetries A(L)(e+) = -0.86(-0.14) (+0.30) and A(L)(e-) = 0.88(-0.71) (+0.12) are observed for inclusive high transverse momentum electrons and positrons in polarized p+p collisions at a center-of-mass energy of sqrt[s] = 500 GeV with the PHENIX detector at RHIC. These e± come mainly from the decay of W± and Z0 bosons, and their asymmetries directly demonstrate parity violation in the couplings of the W± to the light quarks. The observed electron and positron yields were used to estimate W± boson production cross sections for the e± channels of σ(pp → W+ X) × BR(W+ → e+ ν(e)) = 144.1 ± 21.2(stat)(-10.3) (+3.4) (syst) ± 21.6(norm)  pb, and σ(pp → W- X) × BR(W- → e- ν[over ¯](e)) = 31.7 ± 12.1(stat)(-8.2) (+10.1) (syst) ± 4.8(norm)  pb.

Effect of dietary fermented garlic by Weissella koreensis powder on growth performance, blood characteristics, and immune response of growing pigs challenged with Escherichia coli lipopolysaccharide

Two experiments were conducted to investigate the effect of fermented garlic by Weissella koreensis powder (WKG) on pig growth performance and immune responses after an Escherichia coli lipopolysaccharide (LPS) challenge. In Exp. 1, 120 growing barrows (23.5 ± 0.5 kg of BW and 56 d of age) were used in a 35-d experiment to determine the optimal amounts of WKG. Pigs were randomly allotted to 1 of 5 treatments with 6 replicate pens and 4 pigs per pen. Dietary treatments included 1) NC (negative control; basal diet without antibiotics), 2) PC (positive control; basal diet + 1 g of tylosin/kg), 3) WKG1 (basal diet + 1 g of WKG/kg), 4) WKG2 (basal diet + 2 g of WKG/kg), and 5) basal diet + 4 g of WKG/kg. At the end of the feeding period, 12 pigs each were selected from the NC and WKG2 treatment groups, and 6 pigs were injected with LPS (50 μg/kg of BW) and the other 6 pigs with an equivalent amount of sterile saline, resulting in a 2 × 2 factorial arrangement of treatments. Blood samples and rectal temperature data were collected at 0, 2, 4, 6, 8, and 12 h after challenge. The ADG of pigs fed WKG- and antibiotic-supplemented diets was greater (P<0.05) than NC from d 14 to 35 and the overall phase, but no dosage-dependent effects were observed. At the end of the experiment, the fecal E. coli count was linearly reduced by the increasing amounts of WKG at d 35 (P=0.01). Challenge with LPS increased white blood cell counts at 6 and 8 h (P<0.01) and depressed lymphocyte concentration at 4, 8, and 12 h (P<0.01). During challenge, LPS injection increased rectal temperature at 2, 4, 6, and 8 h postchallenge (P<0.05), and WKG2 alleviated (P<0.05) the increase in the temperature at 2 h postchallenge. The LPS injection increased plasma tumor necrosis factor-α and IGF-1 concentrations at 2, 4, 6, 8, and 12 h (P<0.01), whereas an alleviating effect of WKG was observed at 4, 6, and 8 h after LPS challenge (P<0.05). At 2, 4, and 6 h postchallenge, concentration of cluster of differentiation-antigen-4-positive cells and cluster of differentiation-antigen-8-positive cells (CD4(+) and CD8(+), respectively) increased in the LPS treatments (P<0.05), and the WKG2 boosted this effect (P<0.05). In conclusion, dietary supplementation of WKG2 in growing pigs can improve ADG and have a beneficial effect on the immune response during an inflammatory challenge.

Osteoradionecrosis of the hyoid bone: imaging findings

BACKGROUND AND PURPOSE

ORN is a postradiation complication that has been well-documented in the medical literature. Most cases in the head and neck have been described in the mandible or larynx. Only a handful of cases in the hyoid bone are documented, all in the clinical literature. Our purpose is to present the clinical and imaging features of ORN involving the hyoid bone.

MATERIALS AND METHODS

We present a case series of 13 patients with imaging findings highly suggestive of hyoid ORN after radiation therapy for head and neck cancers, in which we observed progressive features of hyoid disruption along with adjacent soft-tissue ulceration.

RESULTS

Pretreatment imaging, when available, showed a normal hyoid. Typical postradiation imaging findings included an initial tongue base ulcerative lesion with air approaching the hyoid bone, and subsequent observation of hyoid fragmentation, often with intraosseous or peri-hyoid air and the absence of associated mass-like enhancement.

CONCLUSIONS

Findings of hyoid fragmentation, cortical disruption, and soft tissue or intraosseous air in the postradiation therapy patient should strongly suggest the diagnosis of hyoid ORN. It is important recognize this entity because the diagnosis may preclude potentially harmful diagnostic intervention and allow more appropriate therapy.

The effect of mosapride (5HT-4 receptor agonist) on insulin sensitivity and GLUT4 translocation

AIMS

We investigated the effect of mosapride, 5HT-4 (5-hydroxytryptamine) agonist, on blood glucose level and insulin sensitivity in subjects with impaired glucose tolerance (IGT) and conducted an in vitro study to evaluate the action mechanism.

METHODS

Thirty IGT patients were randomly assigned to receive either mosapride or placebo for 2 weeks. Biochemical profiles and insulin sensitivity index from euglycemic hyperinsulinemic clamp test were assessed before and after treatment. In cultured myotubes from human skeletal muscle cells, insulin- and mosapride-induced GLUT4 translocation and tyrosine phosphorylation of IRS-1 were determined.

RESULTS

After 2 weeks of treatment with mosapride, glucose disposal rates were significantly increased up to those of control (mosapride 5.47+/-1.72 vs 7.06+/-2.13, P=0.004, placebo 5.42+/-1.85 vs 5.23+/-1.53mgkg(-1)min(-1)). Fasting plasma glucose (FPG) and insulin levels were decreased. Mosapride increased the contents of GLUT4 in plasma membrane representing the increased recruitment of glucose transporters from intracellular pool. While insulin treatment on human skeletal muscle cell resulted in an increased tyrosine phosphorylation of IRS-1, mosapride did not have any effect.

CONCLUSIONS

Mosapride is effective in decreasing FPG without stimulating insulin secretion in IGT subjects, possibly by inducing GLUT4 translocation in skeletal muscles.

The effect of rosiglitazone on insulin sensitivity and mid-thigh low-density muscle in patients with Type 2 diabetes

AIMS

We examined the effect of rosiglitazone on insulin sensitivity, abdominal fat and mid-thigh intramuscular fat distribution, and plasma concentrations of adipocytokines in patients with Type 2 diabetes.

METHODS

Rosiglitazone was administered at a daily dose of 4 mg to 42 Type 2 diabetes patients [age 32-70 years, body mass index (BMI) 17.5-32.6 kg/m(2), 15 women, 27 men] for 12 weeks. Various anthropometric and metabolic profiles, plasma adiponectin, leptin, and resistin levels were measured, and insulin resistance was calculated from the short insulin tolerance test. Body fat composition was assessed by computed tomography.

RESULTS

Twelve weeks' rosiglitazone treatment resulted in improved insulin resistance despite increases in body weight and BMI. There was a significant decrease in abdominal visceral adipose tissue area (145 +/- 65.6 vs. 129 +/- 73.1 cm(2), P = 0.049). Mid-thigh low-density muscle area (TLDMA) increased from 23 +/- 9.6 to 26 +/- 8.2 cm(2) (P = 0.009). There were significant changes in plasma adipocytokines, but they were not significantly correlated with changes in insulin resistance.

CONCLUSIONS

Rosiglitazone treatment resulted in an improvement of insulin responsiveness in Type 2 diabetic subjects, which was associated with the redistribution of visceral and subcutaneous adipose tissue, an increase in TLDMA, and changes in serum adipocytokine levels. Further studies are needed to elucidate the insulin sensitizing mechanism of rosiglitazone on peripheral skeletal muscles.

Inhibition of Japanese encephalitis virus replication by peptide nucleic acids targeting cis-acting elements on the plus- and minus-strands of viral RNA

Japanese encephalitis virus (JEV) is a major cause of acute viral encephalitis in humans. The single-stranded, plus-sense viral genome, which is used for translation and minus-strand RNA synthesis, and its complementary minus-strand viral RNA contain various sequences and RNA secondary structures conserved in flaviviruses, providing potential targets for antisense agents. Here, we investigated the antiviral effects of peptide nucleic acids (PNAs) targeting cis-acting signals at the 5'-untranslated region (UTR), 3'-UTR, and genome cyclization motifs on the plus-strand RNA, as well as the 95-nucleotide 3'-end of the minus-strand RNA, which serves as a template for plus-strand RNA synthesis by the viral RNA-dependent RNA polymerase (RdRp). Among the tested cell-penetrating peptide (CPP)-PNA conjugates, a 17-mer PNA conjugate targeting the top of the 3'-UTR loop structure was most effective in suppressing virus proliferation. In vitro RdRp assays and electrophoretic mobility shift assays using a functional recombinant JEV RdRp showed that the 3'-terminal region-targeting PNAs could inhibit RNA synthesis by competing with viral RdRp for binding to a selected cis-acting element at the 3'-end of plus- and minus-strand viral RNAs. Collectively, our results suggest that CPP-PNA conjugates can suppress JEV proliferation by blocking RNA-protein or RNA-RNA interactions essential for productive viral infection.

Biophoton emission of MDCK cell with hydrogen peroxide and 60 Hz AC magnetic field

We studied biophoton characteristics of Madin-Darby canine kidney (MDCK) cells under the influence of H2O2 by employing a photomultiplier tube (PMT) and a fluorescence microscope. H2O2 was used for producing reactive oxygen species (ROS) in the measurement. Images from a fluorescence microscope show an increase of photon intensity emitted from the sample due to H2O2. By using a PMT we measured quantitative change in biophoton emission with application of H2O2 to the MDCK cell culture, found that the increase of the biophoton is dependent upon the amount of H2O2. The agreement between the results of the PMT and the fluorescence microscope suggests the possibility of quantitative measurement of the influence of ROS on living tissue or cell. In addition we applied a 60 HzAC magnetic field on the cells to investigate the change in reaction between MDCK cell and ROS. It showed that a decay of chemiluminescence intensity has taken a different path following exposure to the magnetic field. As a result, the PMT measurement might be considered as a useful tool for studying biochemical characteristics in relation to ROS.

Cloning, purification, and characterization of chitosanase from Bacillus sp. DAU101

A chitosanase-producing Bacillus sp. DAU101 was isolated from Korean traditional food. This strain was identified on the basis of phylogenetic analysis of the 16S rDNA sequence, gyrA gene, and phenotypic analysis. The gene encoding chitosanase (csn) was cloned and sequenced. The csn gene consisted of an open reading frame of 837 nucleotides and encodes 279 amino acids with a deduced molecular weight of 31,420 Da. The deduced amino acid sequence of the chitosanase from Bacillus sp. DAU101 exhibits 88 and 30 % similarity to those from Bacillus subtilis and Pseudomonas sp., respectively. The chitosanase was purified by glutathione S-transferase fusion purification system. The molecular weight of purified enzyme was about 27 kDa, which suggests the deletion of a signal peptide by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The pH and temperature optima of the enzyme were 7.5 and 50 degrees C, respectively. The enzyme activity was increased by about 1.6-fold by the addition of 5 or 10 mM Ca(2+). However, Hg(2+) and Ni(+) ions strongly inhibited the enzyme. The enzyme produced, GlcN(2-4), were the major products from a soluble chitosan.

Use of sodium transfer tissue biosensor (STTB) for monitoring of marine toxic organism

A highly sensitive sodium (Na+) transfer tissue biosensor (STTB) was designed using a frog bladder membrane to measure paralytic shellfish poisons (PSP). The STTB consists, of a Na+ electrode covered by the membrane, which was then integrated into a flow-through system for continuous measurements. In the absence of Na+ channel blocker, active transfer of Na+ occurred from inside to outside across the frog membrane. When the STTB was used to measure the Na+ -dependent dissociation of PSP, it was able to detect PSB at a level contained in a single cell. However, 5 fg or higher (100 cells or more) is needed for accurate and reproducible measurements. The toxicity obtained by the STTB was significantly correlated (r = 0.9449) to that determined by the HPLC. Therefore, the simple method of the STTB can be used not only to detect a low level PSP in toxic plankton populations, but also to monitor poisons in shellfish.

Effects of basic oxygen furnace slag and inorganic nutrients on the germination of resting cysts of two toxic dinoflagellates

Effects of basic oxygen furnace (BOF) slag, inorganic nutrients and H2S on the germination of resting cysts of two toxic dinoflagellates Alexandrium catenella/tamarense and Gymnodinium catenatum were studied in batch cultures. The germination rate of the test species has increased by 23-25%, when the concentration of NO3--N or H2S in culture medium has increased to 2.0 ppm. At the treatment of enriched NH4+-N and PO43--p, the germination of resting cyst was increased. Nevertheless, the increased range in germination rates was less than those of NO3--N and H2S. When BOF slag in culture medium increased to 50 mg/ml (or 500 g/m2), the cyst germination rate fell to less than 5%. At higher level of concentrations germination was completely inhibited. Adding BOF slag to the culture medium reduced the concentration of inorganic salts and H2S in seawater and sediments, resulting in the inhibition of cyst germination. These findings demonstrate the potential use of BOF slag on the sediments seed bank of red tide organism because it has an ability to inhibit resting cysts germination.

Serum factors associated with neovascular glaucoma following vitrectomy for proliferative diabetic retinopathy

We performed a retrospective study of serum factors associated with neovascular glaucoma that can occur following vitrectomy for proliferative diabetic retinopathy. The medical records of 183 patients (241 eyes) who received vitrectomy between August 1996 and August 2000 were studied retrospectively and subsequently analyzed by linear logistic regression analysis and multiple logistic regression tests. Neovascular glaucoma developed at an average of 2.7 months in 31 of 241 eyes (14.1%). The overall anatomical success rate of retinal attachment was 82.5% (199 eyes in 241 eyes), although it decreased to 45.1% (14 eyes in 31 eyes) in eyes with neovascular glaucoma. Serum cholesterol (P = 0.041) and fibrinogen levels (P = 0.020) were significantly associated with the development of neovascular glaucoma. However, no significant association could be found concerning hypertension, diabetic retinopathy or hypercholesterolemia (P > 0.05). We suggest that serum creatinine, cholesterol and fibrinogen levels can be used to predict the development of neovascular glaucoma in vitrectomized eyes with diabetic retinopathy and can further provide a more active approach to preventing the development of this condition.

Augmented expression of peroxiredoxin I in lung cancer

Comparative proteome analysis was performed between human normal (BEAS 2B) and malignant (A549) lung epithelial cells in an attempt to identify novel biomarkers of lung cancer. Approximately 500 protein spots could be separated by mini two-dimensional electrophoresis and visualized with Coomassie blue R-250. Among those relatively abundant proteins, eight spots were changed more than twofold reproducibly and identified by peptide mass fingerprints using mass spectrometry and database search. The increased proteins in A549 were aldehyde dehydrogenase, peroxiredoxin I, fatty acid binding protein, aldoketoreductase, and destrin, whereas the decreased proteins were galectin-1, transgelin, and stathmin. Since human lung is exposed to continuous oxidative stress, antioxidant enzyme peroxiredoxin I was selected for further investigation and its augmented expression was confirmed in cancer tissues compared to normal tissues from lung cancer patients, suggesting peroxiredoxin I as a potential biomarker of lung cancer.

Solution structure of the SL1 RNA of the M1 double-stranded RNA virus of Saccharomyces cerevisiae

The 20-nucleotide SL1 VBS RNA, 5'-GGAGACGC[GAUUC]GCGCUCC (bulged A underlined and loop bases in brackets), plays a crucial role in viral particle binding to the plus strand and packaging of the RNA. Its structure was determined by NMR spectroscopy. Structure calculations gave a precisely defined structure, with an average pairwise root mean square deviation (RMSD) of 1.28 A for the entire molecule, 0.57 A for the loop region (C8-G14), and 0.46 A for the bulge region (G4-G7, C15-C17). Base stacking continues for three nucleotides on the 5' side of the loop. The final structure contains a single hydrogen bond involving the guanine imino proton and the carbonyl O(2) of the cytosine between the nucleotides on the 5' and 3' ends of the loop, although they do not form a Watson-Crick base pair. All three pyrimidine bases in the loop point toward the major groove, which implies that Cap-Pol protein may recognize the major groove of the SL1 loop region. The bulged A5 residue is stacked in the stem, but nuclear Overhauser enhancements (NOEs) suggest that A5 spends part of the time in the bulged-out conformation. The rigid conformation of the upper stem and loop regions may allow the SL1 VBS RNA to interact with Cap-Pol protein without drastically changing its own conformation.

Proteome analysis of light-induced proteins in Synechocystis sp. PCC 6803: identification of proteins separated by 2D-PAGE using N-terminal sequencing and MALDI-TOF MS

The cyanobacterium Synechocystis sp. PCC 6803 is an ideal model organism for the proteome study of light-induced gene expression because the whole genomic sequence has been determined. The soluble proteins extracted from light- and dark-cultured cells were separated by two-dimensional polyacrylamide gel electrophoresis. Light-induced protein spots electroblotted on a polyvinyldiene difluoride membrane were analyzed by N-terminal Edman sequence determination and followed by CyanoBase. The tryptic digests of some proteins were also confirmed by matrix-assisted laser desorption ionization/time-of-flight (MALDI-TOF) and MS-Fit search. Interestingly, eight proteins were related to photosynthesis and respiration (RbcS/L, CbbA, Gap2, AtpB, CpcB, PsbO, and PsbU). Four proteins (SodB, DnaK, GroEL2, and Tig) were involved in cellular processes and the functions of another two proteins (rehydrin and membrane protein) were unknown. The proteome analysis by N-terminal Edman sequencing and MALDI-TOF enabled us to characterize one-shot protein profiles expressed under different physiological conditions.

Application of a channel biosensor for toxicity measurements in cultured Alexandrium tamarense

The purpose of this study is to examine the toxicity of Alexandrium tamarense strains using a channel biosensor. With this biosensor, we were able to measure very small quantities of PSP toxin contained within an individual plankton cell. However, measurement of at least 100 cells is more desirable for increasing the sensitivity of the assay. Therefore, in the near future, the proposed biosensor system may be used for monitoring the STX (saxitoxin) produced by a few naturally toxic phytoplankton, and also measuring small amounts of toxin in shellfish.

Cardiac phospholipase D2 localizes to sarcolemmal membranes and is inhibited by alpha-actinin in an ADP-ribosylation factor-reversible manner

Myocardial phospholipase D (PLD) has been implicated in the regulation of Ca(2+) mobilization and contractile performance in the heart. However, the molecular identity of this myocardial PLD and the mechanisms that regulate it are not well understood. Using subcellular fractionation and Western blot analysis, we found that PLD2 is the major myocardial PLD and that it localizes primarily to sarcolemmal membranes. A 100-kDa PLD2-interacting cardiac protein was detected using a protein overlay assay employing purified PLD2 and then identified as alpha-actinin using peptide-mass fingerprinting with matrix-assisted laser desorption/ionization mass spectroscopy. The direct association between PLD2 and alpha-actinin was confirmed using an in vitro binding assay and localized to PLD2's N-terminal 185 amino acids. Purified alpha-actinin potently inhibits PLD2 activity (IC(50) = 80 nm) in an interaction-dependent and ADP-ribosylation factor-reversible manner. Finally, alpha-actinin co-localizes with actin and with PLD2 in the detergent-insoluble fraction from sarcolemmal membranes. These results suggest that PLD2 is reciprocally regulated in sarcolemmal membranes by alpha-actinin and ARF1 and accordingly that a major role for PLD2 in cardiac function may involve reorganization of the actin cytoskeleton.

Stage-specific assays to study biosynthetic cargo selection and role of SNAREs in export from the endoplasmic reticulum and delivery to the Golgi

To analyze the role of coat protein type II (COPII) coat components and targeting and fusion factors in selective export from the endoplasmic reticulum (ER) and transport to the Golgi, we have developed three novel, stage-specific assays. Cargo selection can be measured using a "stage 1 cargo capture assay," in which ER microsomes are incubated in the presence of glutathione S-transferase (GST)-tagged Sar1 GTPase and purified Sec23/24 components to follow recruitment of biosynthetic cargo to prebudding complexes. This cargo recruitment assay can be followed by two sequential assays that measure separately the budding of COPII-coated vesicles from ER microsomes (stage 2) and, finally, delivery of cargo-containing vesicles to the Golgi (stage 3). We show how these assays provide a means to identify the snap receptor (SNARE) protein rBet1 as an essential component that is not required for vesicle formation, but is required for vesicle targeting and fusion during ER-to-Golgi transport. In general, these assays provide an approach to characterize the biochemical basis for the recruitment of a wide variety of biosynthetic cargo proteins to COPII vesicles and the role of different transport components in the early secretory pathway of mammalian cells.

Association of HLA with Vogt-Koyanagi-Harada syndrome in Koreans

PURPOSE

To study the distribution of human leukocyte antigen HLA-A/B antigens and HLA-DR/-DQ/-DP alleles and to investigate the immunogenetic background of Korean patients with Vogt-Koyanagi-Harada (VKH) syndrome and clinical course with different types of HLA.

METHODS

Human leukocyte antigen typings were performed in 18 Korean patients with VKH syndrome and in 128 healthy control subjects. HLA-A/B loci serologic typing was performed according to the standard microlymphocytotoxicity technique. DNA was extracted through the salting out method, and HLA-DR phenotyping and HLA-DR4, HLA-DQ, and HLA-DP subtyping were performed with the polymerase chain reaction-sequence specific oligonucleotide probe (PCR-SSOP) method.

RESULTS

Among HLA-A/B antigens typed by the standard microlymphocytotoxicity method, the frequencies of HLA-A31 (RR = 6.1, P<1x10(-2)) and HLA-B55 (RR = 15.8, P<.05) were significantly increased in the patient group compared with the control group. Among HLA-DR/-DQ/-DP alleles subtyped by DNA methods, the frequencies of HLA-DRB1*04 (RR = 45.1, P<1x10(-7)) and HLA-DRB1*07 (RR = 3.2, P<.05) were significantly increased. However, significant decreases in HLA-DRB1*08 (RR = .1, P<.05), HLA-DRB1*13 (RR = .1, P<.05), and HLA-DRB1*14 (RR = .1, P<.05) frequencies were observed. The result of HLA-DR, HLA-DQ, and HLA-DP subtyping showed the significant increase in DRB1*0405 (RR = 45.1, P<1x10(-7)), DQA1*0302 (RR = 12.0, P<1x10(-4)), DQB1*0303 (RR = 5.0, P<1x10(-2)), DQB1*0401 (RR = 18.9, P<1x 10-6), and DPB1*0501 (RR = 3.8, P<.05). However, significant decreases in DQA1*0101 (RR = .1, P< .05), DQA10102 (RR = .1, P<1x10(-2)), DQA1*0103 (RR = .1, P<.05), DQA1*0501 (RR = .1, P<1x10(-2)), DQB1*0301 (RR = .1, P<.05), DQB1*0601 (RR = .1, P<.05), DPB1*0201 (RR = .3, P<.05), and DPB1*0401 (RR = .1, P<.05) frequencies were also observed. In patients with DRB1*0405 itself or HLA-DRB1*0405-DQA1*0302-DQB1*0401 haplotype, a reduction in visual acuity and ocular complications was common.

CONCLUSIONS

These results suggest that HLA-DRB1*0405 itself or HLA-DRB1*0405-DQA1*0302-DQB1*0401 haplotype is greatly increased and may play the most important role in the development and the clinical course of VKH syndrome in Korean patients.

Reaction monitoring of succinylation of collagen with matrix-assisted laser desorption/ionization mass spectrometry

Succinylated collagen was synthesized by the reaction of collagen with succinic anhydride under basic conditions for one hour. Using the matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) technique, the reaction products were directly identified without multi-step separation processes. MALDI-MS monitored the reaction more accurately than the conventional method of sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). From the change in molecular mass during the reaction, it is observed that about 28 succinyl groups are attached to the collagen strand.

Phosphorylation and activation of phospholipase D1 by protein kinase C in vivo: determination of multiple phosphorylation sites

Protein kinase C (PKC) is an important regulator of phospholipase D1 (PLD1). Currently there is some controversy about a phosphorylation-dependent or -independent mechanism of the activation of PLD1 by PKC. To solve this problem, we examined whether PLD1 is phosphorylated by PKC in vivo. For the first time, we have now identified multiple basal phophopeptides and multiple phorbol myristate acetate (PMA) induced phosphopeptides of endogenous PLD1 in 3Y1 cells as well as of transiently expressed PLD1 in COS-7 cells. Down regulation or inhibition of PKC greatly attenuated the PMA-induced phosphorylation as well as the activation of PLD1. In the presence of PMA, purified PLD1 from rat brain was also found to be phosphorylated by PKCalpha in vitro at multiple sites generating seven distinct tryptic phosphopeptides. Four phosphopeptides generated in vivo and in vitro correlated well with each other, suggesting direct phosphorylation of PLD1 by PKCalpha in the cells. Serine 2, threonine 147, and serine 561 were identified as phosphorylation sites, and by mutation of these residues to alanine these residues were proven to be specific phosphorylation sites in vivo. Interestingly, threonine 147 is located in the PX domain and serine 561 is in the negative regulatory "loop" region of PLD1. Mutation of serine 2, threonine 147, or serine 561 significantly reduced PMA-induced PLD1 activity. These results strongly suggest that phosphorylation plays a pivotal role in PLD1 regulation in vivo.

Identification of acylated glycoglycerolipids from a cyanobacterium, Synechocystis sp., by tandem mass spectrometry

Acylated glycoglycerolipids were identified in the total lipid extract from cyanobacterium Synechocystis sp. PCC 6803. These compounds have a palmitoyl group esterified to the hydroxyl group at the C-6 position of the terminal glycosyl moiety of digalactosyl monoacylglycerol and digalactosyl diacylglycerol. Their structural elucidation was accomplished by tandem mass spectrometry coupled with fast atom bombardment ionization. Acylated digalactosyl monoacylglycerol has a structure of 1-hydroxy-2-palmitoyl-3-O-[(6-O-palmitoyl)-alpha-D-galactopyranosyl -(1-->6)-beta-D-galactopyranosyl]-sn-glycerol. This compound has not been reported previously.

Vesicle-associated membrane protein 4 is implicated in trans-Golgi network vesicle trafficking

The trans-Golgi network (TGN) plays a pivotal role in directing proteins in the secretory pathway to the appropriate cellular destination. VAMP4, a recently discovered member of the vesicle-associated membrane protein (VAMP) family of trafficking proteins, has been suggested to play a role in mediating TGN trafficking. To better understand the function of VAMP4, we examined its precise subcellular distribution. Indirect immunofluorescence and electron microscopy revealed that the majority of VAMP4 localized to tubular and vesicular membranes of the TGN, which were in part coated with clathrin. In these compartments, VAMP4 was found to colocalize with the putative TGN-trafficking protein syntaxin 6. Additional labeling was also present on clathrin-coated and noncoated vesicles, on endosomes and the medial and trans side of the Golgi complex, as well as on immature secretory granules in PC12 cells. Immunoprecipitation of VAMP4 from rat brain detergent extracts revealed that VAMP4 exists in a complex containing syntaxin 6. Converging lines of evidence implicate a role for VAMP4 in TGN-to-endosome transport.

Structural identification of glycerolipid molecular species isolated from cyanobacterium Synechocystis sp. PCC 6803 using fast atom bombardment tandem mass spectrometry

Our previous works have demonstrated that fast atom bombardment tandem mass spectrometry can be a valuable tool in determining the complete structure of glycoglycerolipids and glycerophospholipids. Collision-induced dissociation of sodium-adducted molecular ions ([M + Na]+ or [M - H + 2Na]+) generates diverse product ions informative on the double-bond position in fatty acyl groups as well as the polar head group and fatty acid composition. Here we report that this direct and rapid method can be applied to the structural determination of individual molecular species of each glycerolipid class purified from the total lipid extract of cyanobacterium Synechocystis sp. PCC 6803. Especially, based on the preference for the loss of the fatty acyl group positioned at the sn-2, it was proved that all of the molecular species of diacylglycerolipids contained a palmitoyl group exclusively at the sn-2 position. Additionally, lysoglycerolipids, monoacyl forms of four major membrane diacylglycerolipids, were first isolated together from a fresh extract. Using fast atom bombardment mass spectrometry and tandem mass spectrometry, it was found that each lysoglycerolipid had a molecular species with only palmitic acid as a fatty acyl group. Thus, these compounds could be synthesized by specific enzyme-catalyzed hydrolysis of the sn-1 fatty acyl group of the corresponding diacylglycerolipids.