Achievement of Target Gain Larger than Unity in an Inertial Fusion Experiment

On December 5, 2022, an indirect drive fusion implosion on the National Ignition Facility (NIF) achieved a target gain G_{target} of 1.5. This is the first laboratory demonstration of exceeding "scientific breakeven" (or G_{target}>1) where 2.05 MJ of 351 nm laser light produced 3.1 MJ of total fusion yield, a result which significantly exceeds the Lawson criterion for fusion ignition as reported in a previous NIF implosion [H. Abu-Shawareb et al. (Indirect Drive ICF Collaboration), Phys. Rev. Lett. 129, 075001 (2022)PRLTAO0031-900710.1103/PhysRevLett.129.075001]. This achievement is the culmination of more than five decades of research and gives proof that laboratory fusion, based on fundamental physics principles, is possible. This Letter reports on the target, laser, design, and experimental advancements that led to this result.

Lawson Criterion for Ignition Exceeded in an Inertial Fusion Experiment

For more than half a century, researchers around the world have been engaged in attempts to achieve fusion ignition as a proof of principle of various fusion concepts. Following the Lawson criterion, an ignited plasma is one where the fusion heating power is high enough to overcome all the physical processes that cool the fusion plasma, creating a positive thermodynamic feedback loop with rapidly increasing temperature. In inertially confined fusion, ignition is a state where the fusion plasma can begin "burn propagation" into surrounding cold fuel, enabling the possibility of high energy gain. While "scientific breakeven" (i.e., unity target gain) has not yet been achieved (here target gain is 0.72, 1.37 MJ of fusion for 1.92 MJ of laser energy), this Letter reports the first controlled fusion experiment, using laser indirect drive, on the National Ignition Facility to produce capsule gain (here 5.8) and reach ignition by nine different formulations of the Lawson criterion.

Epidemiology and impact of frailty in patients with atrial fibrillation in Europe

BACKGROUND

Frailty is a medical syndrome characterised by reduced physiological reserve and increased vulnerability to stressors. Data regarding the relationship between frailty and atrial fibrillation (AF) are still inconsistent.

OBJECTIVES

We aim to perform a comprehensive evaluation of frailty in a large European cohort of AF patients.

METHODS

A 40-item frailty index (FI) was built according to the accumulation of deficits model in the AF patients enrolled in the ESC-EHRA EORP-AF General Long-Term Registry. Association of baseline characteristics, clinical management, quality of life, healthcare resources use and risk of outcomes with frailty was examined.

RESULTS

Among 10,177 patients [mean age (standard deviation) 69.0 (11.4) years, 4,103 (40.3%) females], 6,066 (59.6%) were pre-frail and 2,172 (21.3%) were frail, whereas only 1,939 (19.1%) were considered robust. Baseline thromboembolic and bleeding risks were independently associated with increasing FI. Frail patients with AF were less likely to be treated with oral anticoagulants (OACs) (odds ratio 0.70, 95% confidence interval 0.55-0.89), especially with non-vitamin K antagonist OACs and managed with a rhythm control strategy, compared with robust patients. Increasing frailty was associated with a higher risk for all outcomes examined, with a non-linear exponential relationship. The use of OAC was associated with a lower risk of outcomes, except in patients with very/extremely high frailty.

CONCLUSIONS

In this large cohort of AF patients, there was a high burden of frailty, influencing clinical management and risk of adverse outcomes. The clinical benefit of OAC is maintained in patients with high frailty, but not in very high/extremely frail ones.

Monocytic MDSCs homing to thymus contribute to age-related CD8+ T cell tolerance of HBV

Hepatitis B virus exposure in children usually develops into chronic hepatitis B (CHB). Although hepatitis B surface antigen (HBsAg)–specific CD8⁺ T cells contribute to resolve HBV infection, they are preferentially undetected in CHB patients. Moreover, the mechanism for this rarely detected HBsAg-specific CD8⁺ T cells remains unexplored. We herein found that the frequency of HBsAg-specific CD8⁺ T cells was inversely correlated with expansion of monocytic myeloid-derived suppressor cells (mMDSCs) in young rather than in adult CHB patients, and CCR9 was upregulated by HBsAg on mMDSCs via activation of ERK1/2 and IL-6. Sequentially, the interaction between CCL25 and CCR9 mediated thymic homing of mMDSCs, which caused the cross-presentation, transferring of peripheral HBsAg into the thymic medulla, and then promoted death of HBsAg-specific CD8⁺ thymocytes. In mice, adoptive transfer of mMDSCs selectively obliterated HBsAg-specific CD8⁺ T cells and facilitated persistence of HBV in a CCR9-dependent manner. Taken together, our results uncovered a novel mechanism for establishing specific CD8⁺ tolerance to HBsAg in chronic HBV infection.

Mitral paravalvular leak 3D printing from 3D-transesophageal echocardiography - proof of concept

Funding Acknowledgements

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Ministry of Science and Higher Education

Background

Paravalvular leak (PVL) may occur  in almost 15% of patients undergoing surgical mitral valve replacement. This complication can cause congestive heart failure and hemolysis. Multimodal imaging including computed tomography (MSCT) and 3D-transesophageal echocardiography (3D-TEE) is essential for assessment of PVLs. 3D-TEE-based 3D-printing might be useful in preprocedural planning of PVL closure for the optimization of transcatether procedures. In contrast to 3D-printing based on MSCT, use of 3D-TEE for segmentation and printing is not standardized.

Purpose

A proof of concept study to evaluate 3D printing of mitral PVLs using 3D-TEE.

Methods

A case of a 64-year-old woman with 2 clinically significant PVLs around a mitral prosthetic valve is presented. In 3D-TEE (Philips Epiq) anteromedial defects were visualized (surgical view). Qlab Station was used to export the 3D recording of PVLs with surrounding tissue in cartesian DICOM format. Next Slicer, a free open-source software, was used for segmentation and preparation of a STL (stereolithography) file. The PVL model was printed with Starsys Objet 30 printer using Med620 material. Diameters PVLs were the same in 3D Echocardiography and 3D printed model (12mm and 9mm).

Results

Printed PVL model and corresponding 3D-TEE image are shown in Figure 1 and Figure 2, respectively.

Conclusion(s)

Proof of concept study confirms feasibility of using standard 3D-TEE and open source software for preparation of 3D models of anatomically complex mitral PVLs. Further studies to assess cost-effectiveness and clinical applicability of the presented methodology are ongoing. Abstract Figure 1.  Abstract Figure 2.

Extracellular Hepatitis B Virus RNAs Are Heterogeneous in Length and Circulate as Capsid-Antibody Complexes in Addition to Virions in Chronic Hepatitis B Patients

Extracellular HBV RNA has been detected in both HBV-replicating cell culture media and sera from chronic hepatitis B (CHB) patients, but its exact origin and composition remain controversial. Here, we demonstrated that extracellular HBV RNA species were of heterogeneous lengths, ranging from the length of pregenomic RNA to a few hundred nucleotides. In cell models, these RNAs were predominantly associated with naked capsids, although virions also harbored a minority of them. Moreover, HBV RNAs in hepatitis B patients' blood circulation were localized in unenveloped capsids in the form of capsid-antibody complexes (CACs) and in virions. Furthermore, we showed that extracellular HBV RNAs could serve as the template for viral DNA synthesis. In conclusion, extracellular HBV RNAs mainly consist of pgRNA or the pgRNA species degraded by the RNase H domain of the polymerase in the process of viral DNA synthesis and circulate as CACs and virions. Their presence in blood circulation of CHB patients may be exploited to develop novel biomarkers for HBV persistence.IMPORTANCE Although increasing evidence suggests the presence of extracellular HBV RNA species, their origin and molecular forms are still under debate. In addition to the infectious virions, HBV is known to secrete several species of incomplete viral particles, including hepatitis B surface antigen (HBsAg) particles, naked capsids, and empty virions, during its replication cycle. Here, we demonstrated that extracellular HBV RNAs were associated with naked capsids and virions in HepAD38 cells. Interestingly, we found that unenveloped capsids circulate in the blood of hepatitis B patients in the form of CACs and, together with virions, serve as vehicles carrying these RNA molecules. Moreover, extracellular HBV RNAs are heterogeneous in length and represent either pregenomic RNA (pgRNA) or products of incomplete reverse transcription during viral replication. These findings provide a conceptual basis for further application of extracellular RNA species as novel biomarkers for HBV persistence.

cIAP1/2-TRAF2-SHP-1-Src-MyD88 Complex Regulates Lipopolysaccharide-Induced IL-27 Production through NF-κB Activation in Human Macrophages

The inhibitors of apoptosis (IAP) proteins, initially described in the context of apoptosis regulation as promoting cell survival, have recently emerged as key regulators of innate immune signaling. As a result, downregulation of IAP via Smac mimetics (SMM) has both survival and immunoregulatory effects. IAPs modulate cytokine production in murine models either as a single agent or in response to LPS. However, the role of SMM and the involvement of IAPs in primary human cells and in particular macrophages with respect to cytokine production and innate immune responses remain largely unknown. IL-27, a member of the IL-12 cytokine family produced by APCs such as macrophages, has broad immunoregulatory properties in both innate and adaptive immune responses. Herein, we show that cellular IAPs (cIAPs) positively regulate LPS-induced IL-27 production in both primary human monocytes and macrophages. Investigations for the signaling mechanism of cIAPs involvement in IL-27 production in human macrophages revealed that LPS-induced IL-27 production is regulated by a novel signaling complex comprising cIAP1/2, TNFR-associated factor 2 (TRAF2), SHP-1, Src, and MyD88 leading to p38, c-Jun N-terminal kinases (JNK) and Akt activation and NF-κB signaling. In cancer cells, SMM induce the production of cytokines by activating the noncanonical alternate NF-κB pathway. However, in human macrophages, SMM do not induce the production of TNF-α and other cytokines while inhibiting LPS-induced IL-27 production by inhibiting the classical NF-κB pathway. These signaling pathways may constitute novel therapeutic avenues for immune modulation of IL-27 and provide insight into the modulatory immune effects of SMM.

Circulating miR-210 and miR-22 combined with ALT predict the virological response to interferon-alpha therapy of CHB patients

Interferon-alpha (IFN-α) therapy of chronic hepatitis B (CHB) patients is constrained by limited response and side effects. We described a panel of circulating microRNAs (miRNAs) which could potentially predict outcome of IFN-α therapy. Here, we report development of a simplified scoring model for personalized treatment of CHB patients. 112 CHB patients receiving IFN-α treatment were randomly divided into a training (n = 75) or a validation group (n = 37). The expression of 15 candidate miRNAs was detected in training group with 5 miRNAs exhibiting significantly different levels (p < 0.0001) between early virological response (EVR) and non-early virological response (N-EVR). These 5 miRNAs were further tested in validation phase. Refinement analyses of results from training phase established a model composed of miR-210, miR-22 and alanine aminotransferase (ALT), with area under ROC curve (AUC) of 0.874 and 0.816 in training and validation groups, respectively. In addition, this model showed prognostic value for sustained virological response (SVR) (AUC = 0.821). Collectively, this simplified scoring model composed of miR-210, miR-22 and ALT can reproducibly predict the EVR and SVR of IFN-α therapy in CHB patients. The model should help to forecast the outcome of IFN-α treatment prior to therapy decision involving nucleoside analogs or IFNs.

HIV and HIV-Tat inhibit LPS-induced IL-27 production in human macrophages by distinct intracellular signaling pathways

Monocyte-derived Mϕs (MDMs) from HIV-infected patients and MDM infected in vitro with HIV exhibit a reduced ability to secrete various cytokines, including IL-12. Recently, IL-27, an IL-12 family cytokine, was shown to inhibit HIV replication in Mϕ. Whether HIV infection or HIV accessory protein(s) impact IL-27 production in Mϕs remains unknown. Herein, we show that in vitro HIV infection, as well as intracellular HIV-Tat (Tat) and Tat peptides, inhibit LPS-induced IL-27 production in human MDMs, suggesting impairment of the TLR4 signaling pathway. To understand the signaling pathways governing HIV or Tat-mediated inhibition of LPS-induced IL-27 production, we first demonstrated that p38 MAPK, PI3K, Src-homology region 2 domain-containing tyrosine phosphatase 1 (SHP-1), and Src kinases regulate LPS-induced IL-27 production in MDMs. Tat caused down-regulation of TNFR-associated factor (TRAF)-6 and inhibitor of apoptosis 1 (cIAP-1) and subsequently decreased phosphorylation of downstream PI3K and p38 MAPKs, which were implicated in LPS-induced IL-27 production. Whereas SHP-1 and Src kinases regulated LPS-induced IL-27 production, Tat did not inhibit these kinases, suggesting that they were not involved in Tat-mediated inhibition of LPS-induced IL-27 production. In contrast to Tat, in vitro HIV infection of MDM inhibited LPS-induced IL-27 production via inhibition of p38 MAPK activation. Overall, HIV and Tat inhibit LPS-induced IL-27 production in human macrophages via distinct mechanisms: Tat through the inhibition of cIAP-1-TRAF-6 and subsequent inhibition of PI3K and p38 MAPKs, whereas HIV through the inhibition of p38 MAPK activation.

Label-free Proteomic Analysis of Exosomes Derived from Inducible Hepatitis B Virus-Replicating HepAD38 Cell Line

Hepatitis B virus (HBV) infection is a major health problem worldwide. Recent evidence suggests that some viruses can manipulate the infection process by packing specific viral and cellular components into exosomes, small nanometer-sized (30-150 nm) vesicles secreted from various cells. However, the impact of HBV replication on the content of exosomes produced by hepatocytes has not been fully delineated. In this work, an HBV-inducible cell line HepAD38 was used to directly compare changes in the protein content of exosomes secreted from HepAD38 cells with or without HBV replication. Exosomes were isolated from supernantants of HepAD38 cells cultured with or without doxycycline (dox) and their purity was confirmed by transmission electron microscopy (TEM) and Western immunoblotting assays. Ion-intensity based label-free LC-MS/MS quantitation technologies were applied to analyze protein content of exosomes from HBV replicating cells [referred as HepAD38 (dox^-)-exo] and from HBV nonreplicating cells [referred as HepAD38 (dox⁺)-exo]. A total of 1412 exosomal protein groups were identified, among which the abundance of 35 proteins was significantly changed following HBV replication. Strikingly, 5 subunit proteins from the 26S proteasome complex, including PSMC1, PSMC2, PSMD1, PSMD7 and PSMD14 were consistently enhanced in HepAD38 (dox^-)-exo. Bioinformatic analysis of differential exosomal proteins confirmed the significant enrichment of components involved in the proteasomal catabolic process. Proteasome activity assays further suggested that HepAD38 (dox^-)-exo had enhanced proteolytic activity compared with HepAD38 (dox⁺)-exo. Furthermore, human peripheral monocytes incubated with HepAD38 (dox^-)-exo induced a significantly lower level of IL-6 secretion compared with IL-6 levels from HepAD38 (dox⁺)-exo. Irreversible inhibition of proteasomal activity within exosomes restored higher production of IL-6 by monocytes, suggesting that transmission of proteasome subunit proteins by HepAD38 (dox^-)-exo might modulate the production of pro-inflammatory molecules in the recipient monocytes. These results revealed the composition and potential function of exosomes produced during HBV replication, thus providing a new perspective on the role of exosomes in HBV-host interaction.

Polarization of Monocytic Myeloid-Derived Suppressor Cells by Hepatitis B Surface Antigen Is Mediated via ERK/IL-6/STAT3 Signaling Feedback and Restrains the Activation of T Cells in Chronic Hepatitis B Virus Infection

Chronic hepatitis B virus (HBV) infection is characterized by T cell tolerance to virus. Although inhibition of T cell responses by myeloid-derived suppressor cells (MDSCs) has been observed in patients with chronic hepatitis B (CHB), the mechanism for expansion of MDSCs remains ambiguous. In this study, a significant increased frequency of monocytic MDSCs (mMDSCs) was shown positively correlated to level of HBsAg in the patients with CHB. We further found hepatitis B surface Ag (HBsAg) efficiently promoted differentiation of mMDSCs in vitro, and monocytes in PBMCs performed as the progenitors. This required the activation of ERK/IL-6/STAT3 signaling feedback. Importantly, the mMDSCs polarized by HBsAg in vitro acquired the ability to suppress T cell activation. Additionally, treatment of all-trans retinoic acid, an MDSC-targeted drug, restored the proliferation and IFN-γ production by HBV-specific CD4(+) and CD8(+) T cells in PBMCs from patients with CHB and prevented increase of viral load in mouse model. In summary, HBsAg maintains HBV persistence and suppresses T cell responses by promoting differentiation of monocytes into mMDSCs. A therapy aimed at the abrogation of MDSCs may help to disrupt immune suppression in patients with CHB.

Innate detection of hepatitis B and C virus and viral inhibition of the response

Viral hepatitis caused by hepatitis B virus (HBV) and hepatitis C virus (HCV) infections poses a significant burden to the public health system. Although HBV and HCV differ in structure and life cycles, they share unique characteristics, such as tropism to infect hepatocytes and association with hepatic and extrahepatic disorders that are of innate immunity nature. In response to HBV and HCV infection, the liver innate immune cells eradicate pathogens by recognizing specific molecules expressed by pathogens via distinct cellular pattern recognition receptors whose triggering activates intracellular signalling pathways inducing cytokines, interferons and anti-viral response genes that collectively function to clear infections. However, HBV and HCV evolve strategies to inactivate innate signalling factors and as such establish persistent infections without being recognized by the innate immunity. We review recent insights into how HBV and HCV are sensed and how they evade innate immunity to establish chronicity. Understanding the mechanisms of viral hepatitis is mandatory to develop effective and safe therapies for eradication of viral hepatitis.

HIV inhibits LPS-induced IL-27 production via HIV tat through the inhibition of TRAF-6, and consequent inhibition of PI3K and p38 and JNK MAPKs in human macrophages (VIR9P.1140)

Monocyte-derived macrophages (MDM) from HIV-infected patients and MDM infected in vitro with HIV manifest inhibition of cytokines including IL12. IL27, an IL12 family cytokine, was shown to inhibit HIV replication in macrophages. Whether HIV infection or HIV accessory protein(s) impact IL27 production in macrophages remains unknown. Herein, we show that in vitro HIV infection as well as intracellular HIV and HIV-tat peptides inhibited LPS-induced IL27 production in MDM suggesting that HIV-tat inhibits IL27 production by impairing TLR-4 signalling. To study the mechanism governing HIV-tat-mediated inhibition of LPS-induced IL27 production, we first established that p38 and c-Jun N-terminal kinase (JNK) mitogen-activated protein kinase (MAPK), the phosphoinositide-3-kinase (PI3K), SRC homology region 2 domain-containing tyrosine phosphatase-1 (SHP-1) and Src kinases regulated LPS-induced IL27 production in MDM. HIV-tat caused TNF receptor associated factor (TRAF)-6 inhibition and consequent decreased phosphorylation of downstream PI3K, and p38 and JNK MAPKs implicated in LPS-induced IL27 production. However, SHP-1 and Src kinases were not involved in HIV-Tat-mediated inhibition of LPS-induced IL27 production. In contrast to HIV-tat, in vitro HIV infection of MDM inhibited LPS-induced p38 and JNK activation. Overall, HIV inhibits LPS-induced IL27 production via HIV tat through the inhibition of TRAF-6, and consequent inhibition of PI3K and p38 and JNK MAPKs in macrophages.

Oral administered particulate yeast-derived glucan promotes hepatitis B virus clearance in a hydrodynamic injection mouse model

Hepatitis B virus (HBV) persistent infection is associated with ineffective immune response for the clearance of virus. Immunomodulators represent an important class of therapeutics, which potentially could be beneficial for the treatment of HBV infection. The particulate yeast-derived glucan (PYDG) has been shown to enhance the innate and adaptive immune responses. We therefore, assessed the efficacy of PYDG in enhancing HBV specific immune responses by employing the hydrodynamic injection-based (HDI) HBV transfection mouse model. Mice were intragatric administered PYDG daily for 9 weeks post pAAV/HBV1.2 hydrodynamic injection. PYDG treatment significantly promoted HBV DNA clearance and production of HBsAb compared to control mice. PYDG treatment resulted in recruitment of macrophages, dendritic cells (DCs) and effector T cells to the liver microenvironment, accompanied by a significantly augmented DCs maturation and HBV-specific IFN-γ and TNF-α production by T cell. In addition, enhanced production of Th1 cytokines in liver tissue interstitial fluid (TIF) was associated with PYDG administration. Live imaging showed the accumulation of PYDG in the mouse liver. Our results demonstrate that PYDG treatment significantly enhances HBV-specific Th1 immune responses, accompanied by clearance of HBV DNA, and therefore holds promise for further development of therapeutics against chronic hepatitis B.

Chemical ordering phenomena in nanostructured FePt: Monte Carlo simulations

Selective surface-induced destabilization of L1₀ superstructure variants is simulated in FePt nanostructures of diverse dimensionalities.

Engagement of CD14 sensitizes primary monocytes to IFN-γ to produce IL-12/23p40 and IL-23 through p38 mitogen-activated protein kinase and independent of the janus kinase/signal transducers and activators of transcription signaling

Interferon (IFN)-γ is a potent stimulator of the IL-12 family Th1 cytokines, including IL-12/23p40 and IL-23, responsible for coordinating the innate and adaptive immune responses. Our results show that IFN-γ induced the production of IL-12/23p40 and IL-23p19 mRNA as well as IL-12p40 and IL-23 proteins in primary human monocytes isolated by positive selection through anti-CD14 microbeads. These results were confirmed by IFN-γ stimulation of CD14-activated monocytes resulting in IL-12/23p40 and IL-23 production. We investigated the signaling pathways governing the regulation of IL-23 and its subunits IL-23p40 and IL-23p19 following IFN-γ stimulation. We observed a differential regulation of IL-23p19, IL-12/23p40, and IL-23 following IFN-γ stimulation. IFN-γ-induced IL-23 and IL-12/23p40 expression was positively regulated by the p38 mitogen-activated protein kinases (MAPKs), independent of the Janus kinase (Jak)/signal transducers and activators of transcription (STAT) signaling. In contrast, IL-12 and IL-23 were negatively regulated by the Jak/STAT, phosphatidylinositol 3-kinase (PI3K), and the c-Jun-N-terminal kinase (JNK) MAPKs in IFN-γ-stimulated monocytes. Overall, our results suggest for the first time a differential positive regulation of IL-12p40 and IL-23 by p38 MAPKs independent of the Jak/STAT pathways and negative regulation by the Jak/STAT, JNK, and PI3K pathways in CD14-activated primary human monocytes stimulated with IFN-γ.

SHP-1-Pyk2-Src protein complex and p38 MAPK pathways independently regulate IL-10 production in lipopolysaccharide-stimulated macrophages

The role of tyrosine phosphatase Src homology region 2 domain-containing phosphatase (SHP)-1 in LPS-activated cytokine production and inflammation was investigated by determining TNF-α and IL-10 production in splenic macrophages employing SHP-1-null (me/me) mouse model. LPS-stimulated me/me splenic macrophages secreted significantly less IL-10 with concomitantly elevated levels of TNF-α compared with wild-type (WT) macrophages irrespective of LPS dose and duration of stimulation. IL-10 significantly inhibited LPS-induced TNF-α production in both me/me and WT macrophages. The critical requirement for SHP-1 in regulating LPS-induced IL-10 and TNF-α production was confirmed by interfering with SHP-1 expression in WT macrophages and by reconstituting me/me macrophages with the SHP-1 gene. To delineate the role of SHP-1 in positive regulation of LPS-induced IL-10 production, signaling proteins representing SHP-1 targets were examined. The results reveal that tyrosine kinases Src and proline-rich tyrosine kinase 2 (Pyk2) regulate SHP-1-dependent LPS-induced IL-10 production and infer that optimal LPS-induced IL-10 production requires an assembly of a protein complex consisting of SHP-1-Pyk2-Src proteins. Moreover, LPS-induced IL-10 production also requires activation of the p38 MAPK independent of SHP-1 function. Overall, to our knowledge our results show for the first time that SHP-1 acts as a positive regulator of LPS-induced IL-10 production in splenic macrophages through two distinct and independent SHP-1-Pyk2-Src and p38 MAPK pathways.

Pressure-induced enhancement of the superconducting properties of single-crystalline FeTe0.5Se0.5

The pressure dependence, up to 11.3 kbar, of basic parameters of the superconducting state, such as the critical temperature (T(c)), the lower and the upper critical fields, the coherence length, the penetration depth, and their anisotropy, was determined from magnetic measurements performed for two single-crystalline samples of FeTe(0.5)Se(0.5). We have found pressure-induced enhancement of all of the superconducting state properties, which entails a growth of the density of superconducting carriers. However, we noticed a more pronounced increase in the superconducting carrier density under pressure than that in the critical temperature which may indicate an appearance of a mechanism limiting the increase of T(c) with pressure. We have observed that the critical current density increases under pressure by at least one order of magnitude.

Vascular endothelial growth factor C and D expression correlates with lymph node metastasis and poor prognosis in patients with resected esophageal cancer

Vascular endothelial growth factors C (VEGF-C) and D (VEGF-D) are important lymphangiogenic factors in human cancers. We studied the expression of VEGF-C and VEGF-D using immunohistochemistry in 73 resected esophageal cancer specimens, and correlated the results with patient clinicopathologic features and survival. High expression of VEGF-C was identified in 40 (54.7%) patients, and it correlated positively with histological grade (p=0.038), tumor stage (p=0.01), depth of tumor invasion (p=0.036) and lymph node metastasis (p=0.001). In 48 of 73 (65.7%) tumors, the VEGF-D protein was also expressed at high levels. VEGF-D immunoreactivity significantly correlated with tumor location (p=0.027), size of tumor (p=0.015), histological grade (p=0.02), depth of invasion (p=0.001) and lymph node metastasis (p=0.018). In logistic multivariate analysis, high expression of VEGF-C (OR 1.941, 95% CI 1.263-7.289, p=0.024) was associated with lymph node metastasis. Calculating the prognostic relevance revealed that both VEGF-C and VEGF-D correlated with decreased overall survival (p=0.01, p=0.003), disease free survival (p=0.02, p=0.006), and cancer-specific survival (p=0.03, p=0.005). In conclusion, our results suggest that high levels of both VEGF-C and VEGF-D proteins are associated with lymph node involvement, and that VEGF-C expression is an independent predictor of risk for lymph node metastasis in esophageal cancer. In locally advanced disease, overexpression of VEGF-C and VEGF-D may be useful in identifying patients who are more likely to have a poor prognosis even after curative resection.

Breast cancer cells proliferation is regulated by tyrosine phosphatase SHP1 through c-jun N-terminal kinase and cooperative induction of RFX-1 and AP-4 transcription factors

In this study, we show that proliferation of breast cancer cells is suppressed by IGF-1-activated JNK MAPK pathway. The molecular mechanism by which c-jun-NH,-kinase (JNK) activation induces antiproliferative signals in IGF-1-stimulated breast cancer cells remains unknown. Tyrosine phosphatase SHP1 is known to negatively regulate signal transduction pathways activated by cell surface receptors including IGF-1. Moreover, SHP1 transcript and protein levels are increased in epithelial tumors. Therefore, we hypothesized that IGF-activated JNK induces expression of SHP1 in breast cancer cells. To further clarify the role of SHP1 in tumor growth, we correlated the proliferation rates of breast adenocarcinoma cells with SHP1 expression and JNK activation. We show that proliferation of serum- or IGF-1-stimulated breast adenocarcinoma cells is negatively regulated by SHP1 and show for the first time that IGF-1-activated JNK induces SHP1 expression in MCF-7 cells used as experimental model. In an attempt to understand the mechanism by which serum- or IGF-1-activated JNK induces SHP1 expression resulting in suppression of cell proliferation, we reveal for the first time that in serum- or IGF-1-stimulated breast cancer MCF-7 cells, JNK induces SHP1 expression through the binding of AP-4 and RFX-1 transcription factors to the epithelial tissue-specific SHP1 promoter. Overall, we show for the first time that IGF-1-stimulated proliferation of breast adenocarcinoma cells is negatively regulated by SHP1 through activation of JNK.

Peritoneal T lymphocyte regulation by macrophages

The T cell composition of the peritoneal cavity (PerC) in naïve BALB/c, C57BL/6, DBA/2J, and B-1 B cell-defective BALB.xid mice was investigated. The BALB.xid PerC T cell pool had a high CD4:CD8 T cell ratio relative to the other strains whose ratios were similar to those found in their lymph node and spleen. All mice had significant representation of T cells with an activated (CD25(+), GITR(hi), CD44(hi), CD45RB(lo), CD62L(lo)) phenotype and low numbers of Foxp3(+) T(reg) cells in their PerC. Despite a phenotype indicative of activation, peritoneal T cell responses to CD3 ligation were very low for C57BL/6 and BALB.xid, but not BALB/c, mice. Enzyme inhibition and cytokine neutralization studies revealed active suppression of the T cell response mediated by the macrophages that represent a significant portion of PerC leucocytes. Driven by IFNγ to express iNOS, macrophages suppressed T cell activation in vitro by arginine catabolism. Although BALB/c T cells were also in a macrophage-dense environment their limited IFNγ production failed to trigger suppression. This difference between BALB/c and BALB.xid PerC T cells suggests a role for xid in shaping macrophage-mediated immune regulation.

Study of reorientation processes in L10-ordered FePt thin films

We report on the development of structural and magnetic order in epitaxially grown L1₀ FePt thin films. Upon annealing, the easy axis of magnetization changes from the out-of-plain into the in-plain direction. We found that the overall fraction of reoriented domains first increases but after certain time decreases before achieving a saturated state. The results are based on conversion electron Mössbauer spectroscopy studies and confirm Monte Carlo simulations in nano-layered FePt. We present a modified version of the Johnson-Mehl-Avrami (JMA) model adequately describing the experimental findings. Two dynamical processes, the first being a 2D-growth, dominate the initial state of sample annealing and the second being a 3D-growth, dominate the late stage close to saturation. From an Arrhenius plots of JMA coefficients for both processes we extracted the activation energies of the underlying dynamics which are 1.5(1) eV for disordering and 0.8(2) eV for ordering.

Differences in growth and transcriptomic profile of bovine mammary epithelial monolayer and three-dimensional cell cultures

Mammary epithelial cells (MECs) are characterized by specific spatial architecture with several distinguishing features such as: polarized morphology, specialized cell-cell contacts, and attachment to an underlying basement membrane. Three dimensional (3D) basement membrane cultures provide a unique opportunity to model the architecture of epithelium in vitro. The aim of this study was to characterize the growth of bovine mammary epithelial cell line BME-UV1 in 3D culture on Matrigel and identification of differently expressed genes in bovine MECs forming polarized structures in comparison to conventional monolayer (2D) cell culture. We demonstrate that BME-UV1 cells grown on Matrigel form polarized acinar structures during 16 days of culture. A microarray study has proven that the difference in spatial architecture between MECs cultured in monolayer and 3D system is reflected by differences in transcriptomic profile. Microarray data analysis showed 40 differentially expressed genes with statistical significance (p<0.05) and characterized biological functions. Identified genes comprised of cytoskeletal proteins, extracellular matrix components, kinases such as: Rac serine/threonine kinase, SRPK, protooncogene tyrosine-protein kinase ABL1, uridine cytidine kinase and proteins with nucleic acid binding / transcription factor activity. Products of those genes are involved in processes which are known to participate in regulating mammary gland polarization and function.

Role of autophagy in mammary gland development

Autophagy is a highly conserved catabolic process responsible for degradation and recycling of long-lived proteins and organelles by lysosomes. This degradative pathway, together with proteasome system is particularly important during development and under certain environmental stress conditions. This review summarizes the latest achievements of studies aiming to explore the role of autophagy in development and differentiation of eukaryotic cells. It shows the importance of this process in the development of lower eukaryotic organisms such as Dicyostelium discoideum, and Caenorhabditis elegans, as well as functions of autophagy and autophagy related genes (Atg) in development and differentiation of higher eukaryotic organisms. The review is focused on the results of studies conducted on mammary gland, as it is a good model for studying the mechanisms controlling higher eukaryotic organisms' development. Studies have shown that autophagy is involved in the removal of epithelial cells during formation of alveolar structures, indicating its role in mammogenesis. There are also evidences of involvement of Atg's in epithelial tumors development. Context dependent manipulations of autophagic pathways may create more effective anticancer therapies in the future.

High-level expression of cancer/testis antigen NY-ESO-1 and human granulocyte-macrophage colony-stimulating factor in dendritic cells with a bicistronic retroviral vector

Tumor-specific genes delivered to dendritic cells (DCs) have been used for the generation of cytotoxic T cells (CTLs), but their application has been limited on the one hand by low viral titers resulting in low transduction efficiency and poor protein production, and on the other hand by immunogenicity of the selectable marker and poor viability of the DCs. We addressed these limitations by creating a multipurpose master vector (pMV) and cloning the tumor gene NY-ESO-1, which is highly expressed in more than 50% of advanced myeloma patients. pMV was constructed from a Moloney murine leukemia virus (Mo-MuLV)-based retroviral backbone with the following features: (1) an extended packaging signal to achieve high viral titers, (2) a splice acceptor region to facilitate protein production, (3) a nonimmunogenic selectable marker, dihydrofolate reductase-L22Y (DHFR(L22Y)), to exclude the generation of CTLs against the selectable marker, (4) an internal ribosomal entry site between the tumor-specific gene (NY-ESO-1) and the selectable marker DHFR(L22Y) for coexpression of two heterologous gene products from a single bicistronic mRNA, minimizing the possibility of differential expression of these two genes, and (5) human granulocyte-macrophage colony-stimulating factor (hGM-CSF) cDNA driven by the human T-lymphotropic virus promoter to enhance DC function and viability. Recombinant virus of pMV-NY-ESO-1 was generated with vesicular stomatitis virus G envelope protein (VSV-G) in the GP2-293 cell line for efficient transduction. We present evidence that the DC phenotype is unaltered after transduction and that more than 85% of DCs express NY-ESO-1, which secrete approximately 40 ng of GM-CSF per 10(6) DCs.

Dexamethasone inhibits IL-12p40 production in lipopolysaccharide-stimulated human monocytic cells by down-regulating the activity of c-Jun N-terminal kinase, the activation protein-1, and NF-kappa B transcription factors

IL-12 plays a critical role in the development of cell-mediated immune responses and in the pathogenesis of inflammatory and autoimmune disorders. Dexamethasone (DXM), an anti-inflammatory glucocorticoid, has been shown to inhibit IL-12p40 production in LPS-stimulated monocytic cells. In this study, we investigated the molecular mechanism by which DXM inhibits IL-12p40 production by studying the role of the mitogen-activated protein kinases (MAPKs), and the key transcription factors involved in human IL-12p40 production in LPS-stimulated monocytic cells. A role for c-Jun N-terminal kinase (JNK) MAPK in LPS-induced IL-12p40 regulation in a promonocytic THP-1/CD14 cell line was demonstrated by using specific inhibitors of JNK activation, SP600125 and a dominant-negative stress-activated protein/extracellular signal-regulated kinase kinase-1 mutant. To identify transcription factors regulating IL-12p40 gene transcription, extensive deletion analyses of the IL-12p40 promoter was performed. The results revealed the involvement of a sequence encompassing the AP-1-binding site, in addition to that of NF-kappaB. The role of AP-1 in IL-12p40 transcription was confirmed by using antisense c-fos and c-jun oligonucleotides. Studies conducted to understand the regulation of AP-1 and NF-kappaB activation by JNK MAPK revealed that both DXM and SP600125 inhibited IL-12p40 gene transcription by inhibiting the activation of AP-1 and NF-kappaB transcription factors as revealed by luciferase reporter and gel mobility shift assays. Taken together, our results suggest that DXM may inhibit IL-12p40 production in LPS-stimulated human monocytic cells by down-regulating the activation of JNK MAPK, the AP-1, and NF-kappaB transcription factors.

SHP-1 negatively regulates neuronal survival by functioning as a TrkA phosphatase

Nerve growth factor (NGF) mediates the survival and differentiation of neurons by stimulating the tyrosine kinase activity of the TrkA/NGF receptor. Here, we identify SHP-1 as a phosphotyrosine phosphatase that negatively regulates TrkA. SHP-1 formed complexes with TrkA at Y490, and dephosphorylated it at Y674/675. Expression of SHP-1 in sympathetic neurons induced apoptosis and TrkA dephosphorylation. Conversely, inhibition of endogenous SHP-1 with a dominant-inhibitory mutant stimulated basal tyrosine phosphorylation of TrkA, thereby promoting NGF-independent survival and causing sustained and elevated TrkA activation in the presence of NGF. Mice lacking SHP-1 had increased numbers of sympathetic neurons during the period of naturally occurring neuronal cell death, and when cultured, these neurons survived better than wild-type neurons in the absence of NGF. These data indicate that SHP-1 can function as a TrkA phosphatase, controlling both the basal and NGF-regulated level of TrkA activity in neurons, and suggest that SHP-1 regulates neuron number during the developmental cell death period by directly regulating TrkA activity.

Therapy increases poly-ADP-ribose and p53-Ser392-P levels in recurrent squamous cell lung cancer

p53 protein is a critical regulator of the cell cycle and apoptosis and its levels and functions change in response to many stimuli. To assess whether the cytotoxic drugs induce DNA changes, affect phosphorylation and stability of p53 protein, we determined poly-ADP-ribose levels, the expression of p53 protein and its carboxyl-terminal Ser-392 phosphate levels in fiberoptic bronchoscopy biopsy samples taken from patients suffering from recurrent squamous cell lung cancer before and after radiotherapy and chemotherapy. All 14 patients included in this study were in IA-IIIA clinical stage prior to surgery. Radiation/chemotherapy decreased G2/M cell numbers but increased S-phase cells by almost 50% compared to ploidy status before therapy, while median p53 expression was doubled (109% increase). p53 phosphorylated on Ser-392 was also increased by approximately 70% in patients treated with radiotherapy and with chemotherapy and correlated with elevated poly-ADP-ribose levels. Our data suggest that apart from changes in p53 quantity, posttranslational phosphorylation/dephosphorylation-mediated alterations may play an important role in neoplastic cell proliferation as well as in antiproliferative activity of drugs inducing DNA damage and apoptosis.

Tumor necrosis factor-alpha induces functionally active hyaluronan-adhesive CD44 by activating sialidase through p38 mitogen-activated protein kinase in lipopolysaccharide-stimulated human monocytic cells

Interaction of CD44, an adhesion molecule, with its ligand, hyaluronan (HA), in monocytic cells plays a critical role in cell migration, inflammation, and immune responses. Most cell types express CD44 but do not bind HA. The biological functions of CD44 have been attributed to the generation of the functionally active, HA-adhesive form of this molecule. Although lipopolysaccharide (LPS) and cytokines induce HA-adhesive CD44, the molecular mechanism underlying this process remains unknown. In this study, we show that LPS-induced CD44-mediated HA (CD44-HA) binding in monocytes is regulated by endogenously produced tumor necrosis factor (TNF)-alpha and IL-10. Furthermore, p38 mitogen-activated protein kinase (MAPK) activation was required for LPS- and TNF-alpha-induced, but not IL-10-induced, CD44-HA-binding in normal monocytes. To dissect the signaling pathways regulating CD44-HA binding independently of cross-regulatory IL-10-mediated effects, IL-10-refractory promonocytic THP-1 cells were employed. LPS-induced CD44-HA binding in THP-1 cells was regulated by endogenously produced TNF-alpha. Our results also suggest that lysosomal sialidase activation may be required for the acquisition of the HA-binding form of CD44 in LPS- and TNF-alpha-stimulated monocytic cells. Studies conducted to understand the role of MAPKs in the induction of sialidase activity revealed that LPS-induced sialidase activity was dependent on p42/44 MAPK-mediated TNF-alpha production. Blocking TNF-alpha production by PD98059, a p42/44 inhibitor, significantly reduced the LPS-induced sialidase activity and CD44-HA binding. Subsequently, TNF-alpha-mediated p38 MAPK activation induced sialidase activity and CD44-HA binding. Taken together, our results suggest that TNF-alpha-induced p38 MAPK activation may regulate the induction of functionally active HA-binding form of CD44 by activating sialidase in LPS-stimulated human monocytic cells.

Analysis of pCU1 replication origins: dependence of oriS on the plasmid-encoded replication initiation protein RepA

The broad-host-range replicon of the plasmid pCU1 has three origins of vegetative replication called oriB, oriS, and oriV. In the multi-origin replicon, individual origins can distinguish among replication factors provided by the host. It has been found that during replication in Escherichia coli polA(-) host, oriS was the only active origin of a mutant pCU1 derivative bearing a mutation in the gene encoding replication initiation protein RepA. To further investigate the capacity of oriS to function in an E. coli polA(-) host we constructed a number of clones of the basic replicon of pCU1 containing oriS as the only replication origin. An oriS construct created with pUC18 could transform the polA(-) strain when RepA was supplied in trans. When the oriS region (between nucleotides 290 and 832) was ligated to an antibiotic resistance Omega fragment, the construct could be recovered as a plasmid from polA(+) strain if functional RepA was provided in trans. Our results therefore indicate that the basic replicon of pCU1, containing oriS as the sole origin, does require RepA to initiate plasmid replication in E. coli

Differential regulation of CD44 expression by lipopolysaccharide (LPS) and TNF-alpha in human monocytic cells: distinct involvement of c-Jun N-terminal kinase in LPS-induced CD44 expression

Alterations in the regulation of CD44 expression play a critical role in modulating cell adhesion, migration, and inflammation. LPS, a bacterial cell wall component, regulates CD44 expression and may modulate CD44-mediated biological effects in monocytic cells during inflammation and immune responses. In this study, we show that in normal human monocytes, LPS and LPS-induced cytokines IL-10 and TNF-alpha enhance CD44 expression. To delineate the mechanism underlying LPS-induced CD44 expression, we investigated the role of the mitogen-activated protein kinases (MAPKs), p38, p42/44 extracellular signal-regulated kinase, and c-Jun N-terminal kinase (JNK) by using their specific inhibitors. We demonstrate the involvement, at least in part, of p38 MAPK in TNF-alpha-induced CD44 expression in both monocytes and promonocytic THP-1 cells. However, neither p38 nor p42/44 MAPKs were involved in IL-10-induced CD44 expression in monocytes. To further dissect the TNF-alpha and LPS-induced signaling pathways regulating CD44 expression independent of IL-10-mediated effects, we used IL-10 refractory THP-1 cells as a model system. Herein, we show that CD44 expression induced by the LPS-mediated pathway predominantly involved JNK activation. This conclusion was based on results derived by transfection of THP-1 cells with a dominant-negative mutant of stress-activated protein/extracellular signal-regulated kinase kinase 1, and by exposure of cells to JNK inhibitors dexamethasone and SP600125. All these treatments prevented CD44 induction in LPS-stimulated, but not in TNF-alpha-stimulated, THP-1 cells. Furthermore, we show that CD44 induction may involve JNK-dependent early growth response gene activation in LPS-stimulated monocytic cells. Taken together, these results suggest a predominant role of JNK in LPS-induced CD44 expression in monocytic cells.

CD4 is active as a signaling molecule on the human monocytic cell line Thp-1

CD4 is a 56-kDa membrane glycoprotein expressed by a subset of T cells, by cells of the monocyte/macrophage lineage, and by eosinophils and dendritic cells. CD4 serves as a coreceptor for HIV and IL-16. T cell CD4 mediates signal transduction by associating with the protein tyrosine kinase p56(lck); this interaction does not exist in monocytes. We wished to elucidate the mechanism(s) by which monocyte CD4 transduces signals. Stimulation of CD4 on Thp-1 monocytic cells induced a Ca(2+) flux and the time-dependent activation of phosphotyrosine proteins ranging from 35 to 180 kDa. We identified the 140- and 85-kDa proteins as phospholipase C gamma (PLC-gamma) and the regulatory subunit of phosphatidylinositol 3-kinase (PI-3K), respectively. Using immunoprecipitation/Western immunoblotting however, we were unable to show any direct association between CD4 and PLC-gamma, PI-3K, or other known signaling proteins. To identify proteins capable of associating with the cytoplasmic tail of CD4, we fused it with gluthatione S-transferase and used the fusion protein in far Western and pull-down experiments. In both types of experiments, the fusion protein routinely associated with 45- and 55-kDa proteins. Mass spectrometry analysis of the tryptic peptides generated from these two proteins indicated novel sequences.

Distinct role of p38 and c-Jun N-terminal kinases in IL-10-dependent and IL-10-independent regulation of the costimulatory molecule B7.2 in lipopolysaccharide-stimulated human monocytic cells

The costimulatory molecule B7.2 (CD86) plays a vital role in immune activation and development of Th responses. The molecular mechanisms by which B7.2 expression is regulated are not understood. We investigated the role of mitogen-activated protein kinases (MAPK) in the regulation of B7.2 expression in LPS-stimulated human monocytic cells. LPS stimulation of human monocytes resulted in the down-regulation of B7.2 expression that could be abrogated by anti-IL-10 Abs. Furthermore, SB202190, a specific inhibitor of p38 MAPK, inhibited LPS-induced IL-10 production and reversed B7.2 down-regulation, suggesting that LPS-induced B7.2 down-regulation may be mediated, at least in part, via regulation of IL-10 production by p38 MAPK. In contrast to human promonocytic THP-1 cells that are refractory to the inhibitory effects of IL-10, LPS stimulation enhanced B7.2 expression. This IL-10-independent B7.2 induction was not influenced by specific inhibitors of either p38 or p42/44 MAPK. To ascertain the role of the c-Jun N-terminal kinase (JNK) MAPK, dexamethasone, an inhibitor of JNK activation, was used, which inhibited LPS-induced B7.2 expression. Transfection of THP-1 cells with a plasmid expressing a dominant-negative stress-activated protein/extracellular signal-regulated kinase kinase 1 significantly reduced LPS-induced B7.2 expression, thus confirming the involvement of JNK. To study the signaling events downstream of JNK activation, we show that dexamethasone did not inhibit LPS-induced NF-kappaB activation in THP-1 cells, suggesting that JNK may not be involved in NF-kappaB activation leading to B7.2 expression. Taken together, our results reveal the distinct involvement of p38 in IL-10-dependent, and JNK in IL-10-independent regulation of B7.2 expression in LPS-stimulated monocytic cells.

The preoperative study of mediastinal lymph nodes metastasis in lung cancer by endoscopic ultrasonography (EUS) and helical computed tomography (CT)

OBJECTIVE

Accurate staging of mediastinal lymph nodes in patients with lung cancer is fundamental for their treatment and prognosis. The aim of this study was to compare the value of EUS and CT staging in patients with non-small-cell lung cancer (NSCLC) with postsurgical stage.

METHODS

Ninety two patients with NSCLC underwent EUS and CT for preoperative detection of metastases to the mediastinal lymph nodes. EUS examinations were done with the ultrasonic linear array scanning echoendoscope (FG 32 UA, Hitachi/Pentax), CT-Toshiba Exvision GX scanner, with 24-s spiral acquisition, pitch 1:1 (7 mm collimation, 4 mm reconstruction index), during i.v. administration of non-ionic iodinated contrast media.

RESULTS

The frequency of mediastinal involvement was 22.7%. The regions most accessible by EUS evaluation were subaortic, subcarinal and paraoesophageal lymph nodes. On a per-patient basis, EUS and CT results were: sensitivity 70.0 and 60.0%, specificity 80.6 and 72.6%, accuracy 77.2 and 68.5%. On a per-sites basis, the sensitivity of EUS evaluation was 78.8%, specificity 89.9%, accuracy 87.7%, comparing with CT-63.6, 84.0, 79.9%, respectively. When the EUS and CT images were analysed in combination, the sensitivity increased to 86.4%.

CONCLUSION

We believe that EUS and CT should be used together for preoperative non-invasive staging of mediastinal lymph nodes in patients with NSCLC.

Do the intervertebral disc cells respond to different levels of hydrostatic pressure?

OBJECTIVE

To test the hypothesis that hydrostatic pressure directly affects the synthesis of collagen and proteoglycan by intervertebral disc cells.

DESIGN

By the use of pressure vessels, hydrostatic pressure was applied to intervertebral disc cells cultured in alginate.

BACKGROUND

The influence of compression (both hydrostatic and axial) on chondrocyte metabolism was examined in a number of earlier studies. However, in most of these studies, articular cartilage, not intervertebral disc was used, and in none of these was hydrostatic pressure applied to intervertebral disc cells cultured in alginate.

METHODS

Fresh cells were harvested from the lumbar intervertebral discs of dogs. Before their suspension in an alginate gel system, the cells were plated and expanded until they reached confluence. Then, by use of the alginate gel system, the cells were exposed (for up to 9 days) to specific values of hydrostatic pressure inside two stainless steel pressure vessels. One vessel was kept at 0.35 MPa and the other at atmospheric pressure (approximately 0.1 MPa). The effects of 0.35 MPa were compared against atmospheric pressure by measuring the incorporation of [3H]-proline and [35S]-sulfate into collagen and proteoglycans, respectively, for the anulus cells and nucleus cells separately, and by determining whether this incorporation was reflected by changes in the levels of mRNA for aggrecan and Types I and II collagen.

RESULTS

Proteoglycan synthesis was inhibited at 0.35 MPa as compared to atmospheric pressure for both the nucleus and anulus cells, whereas collagen synthesis was stimulated in the nucleus cells, but inhibited in the anulus cells. The mRNA levels of collagen 1A and collagen 2A decreased in the anulus but showed a differential response in the nucleus (collagen 1A increased, while collagen 2A decreased). The mRNA levels for aggrecan core protein decreased in the anulus and increased in the nucleus.

CONCLUSIONS

Hydrostatic pressure directly affects the synthesis of collagen and proteoglycan by the intervertebral disc cells.

RELEVANCE

This in vitro study reveals the direct effect of hydrostatic pressure on disc cells, in the absence of other factors. However, circumspection must be applied when comparisons between these results, from in vitro experiments on dog disc cells, are extrapolated and applied to the whole discs of humans.

Small molecule insulin receptor activators potentiate insulin action in insulin-resistant cells

In type 2 diabetes, impaired insulin signaling leads to hyperglycemia and other metabolic abnormalities. To study a new class of antidiabetic agents, we compared two small, nonpeptide molecules that activate insulin receptor (IR) beta-subunit tyrosine kinase activity: Merck L7, a direct IR agonist, and Telik's TLK16998, an IR sensitizer. In rat hepatoma cells (HTCs) that overexpress the IR (HTC-IR), IR autophosphorylation was directly activated by L7 in the absence of insulin. TLK16998 did not directly activate IR autophosphorylation, but it enhanced IR autophosphorylation in the presence of insulin. Tyrosine phosphorylation of an endogenous 185-kDa IR substrate was also significantly enhanced by both Merck L7 alone and TLK16998 plus insulin. Adding TLK16998 to L7 produced synergistic effects, further indicating that these two compounds act on the IR through separate mechanisms. We next studied HTC-IR(Delta485-599) cells, which overexpress a mutant IR with a deletion in the alpha-subunit connecting domain that does not undergo autophosphorylation in response to insulin binding. L7 was able to directly activate autophosphorylation of the deletion mutant IR in these cells, whereas TLK16998 had no effect. Compounds were then tested in three other cell models of impaired IR function. Both TLK16998 and Merck L7 improved IR autophosphorylation in cells with diminished IR signaling due to either treatment with tumor necrosis factor-alpha or overexpression of membrane glycoprotein PC-1. However, in TPA (tetradecanoylphorbol acetate)-treated cells, TLK16998 but not Merck L7 was able to significantly reverse the impaired insulin-stimulated IR autophosphorylation. In summary, these two classes of IR activators selectively increased IR function in a variety of insulin-resistant cell lines.

Differential effect of IL-4 and IL-13 on CD44 expression in the Burkitt's lymphoma B cell line BL30/B95-8 and in Epstein-Barr virus (EBV) transformed human B cells: loss of IL-13 receptors on Burkitt's lymphoma B cells

IL-4 and IL-13, cytokines with similar biological effects may influence growth and progression of B-cell tumors through regulation of key cell surface molecules important in intercellular communications. In this study, we demonstrate that IL-4 and IL-13 exhibited differential effects on CD23 and CD44 expression and binding to hyaluronan in BL30/B95-8, a Burkitt's lymphoma (BL), and MK3.31, an Epstein-Barr virus transformed normal human B cell line (B-LCL). Studies conducted to understand the molecular mechanisms underlying this differential effect show that IL-4 induced phosphorylation of JAK1, JAK3, and STAT6 in BL30/B95-8 cells and of JAK3 and STAT6 in MK 3.31 cells. In contrast, IL-13 failed to induce the phosphorylation of JAK kinases or STAT6 proteins in these cell lines. The inability of BL30/B95-8 cells to respond to IL-13 was attributed to the loss of expression of IL-13R subunits alpha1 and alpha2, a finding confirmed for a number of other BL cell lines examined.