Novel shift of Jak/Stat signalling characterizes the protective effect of aurintricarboxylic acid (ATA) from tumor necrosis factor-alpha toxicity in human B lymphocytes

Rat Basophilic Leukemia Cells (RBL-2H3) Generate Prostaglandin D2 (PGD2) after Regulated upon Activation, Normal T-cell Expressed and Secreted (RANTES) activation

Increasing evidence indicates that local neurogenic inflammation, possibly in response to different stimuli, may be involved in sensory nerve sensitization, migraine generation and some other precipitating events leading to neuronal dysfunction in the brain. In addition, mast cells generate eicosanoids that are linked to asthma and other inflammatory diseases. Regulated upon activation, normal T-cell expressed and secreted (RANTES) is a small protein and a prototype member of the CC chemokine-beta subfamily with chemoattractant and inflammatory properties. In this study we used the RBL-2H3 cell line to determine whether or not these cells generate prostaglandin D2 (PGD2) after treatment with RANTES. After 4 hours of incubation, RBL-2H3 cells cultured with RANTES at 20 ng/mL released large amounts of PGD2 in a dose-response manner compared to control. Moreover, RBL-treated RANTES generated a large quantity of histamine. Our study confirms once again the proinflammatory action of RANTES, in this case acting on the stimulation of the arachidonic acid cascade product PGD2.

The Differential Expression of Galectin-1 and Galectin-3 in Normal Lymphoid Tissue and Non-Hodgkin's and Hodgkin's Lymphomas

The WHO classification of lymphomas was established on the basis of clinical, morphological, immunohistochemical and genetic criteria. However, each entity displays its own spectrum of clinical aggressiveness. Treatment success varies widely and is not predictable. Since galectins are involved in oncogenesis and the physiology of immune cells, we investigated whether galectin-1 and galectin-3 immunohistochemical expression could differ in 25 normal lymphoid tissues, 42 non-Hodgkin's and 14 Hodgkin's lymphomas. Immunohistochemical galectin expression was submitted to semi-quantitative and quantitative (computer-assisted microscopy) evaluations. This study is completed by an analysis (by means of quantitative RT-PCR) of galectin-3 mRNA expression in 3 normal lymph nodes, 3 follicular lymphomas (FLs) and 3 diffuse large B-cell lymphomas (DLBCLs). The data show that in normal lymphoid tissue, lymphocytes do not express galectin-1 and rarely express galectin-3. In contrast, galectin-3 was expressed in 8 of the 16 DLBCL cases and in 1 of the 8 FL cases. Furthermore, galectin-3 mRNA was expressed 3-times more in the DLBCLs than in the FLs. While the blood vessel walls of the lymphomas expressed galectin-1, the vessel walls of normal lymphoid tissues did not. This expression of galectin-1 in blood vessel walls was correlated with vascular density. The present study thus shows that DLBCL can be distinguished from normal lymphoid tissue and other lymphomas on the basis of galectin-3 expression.

Constitutive and Stimulated Production of Vegf by Human Megakaryoblastic Cell Lines: Effect on Proliferation and Signaling Pathway

Release of vascular endothelial growth factor (VEGF) and other candidate angiogenic factors such as basic fibroblast growth factor and transforming growth factor β, may play a role in sustaining neoplastic cell proliferation and tumor growth. We evaluated VEGF expression and synthesis in the two erythro-megakaryocytic cell lines B1647, HEL and one megakaryocyte cell line MO7 expressing erythroid markers. In this study RT-PCR was performed to evaluate VEGF expression and that of its receptor KDR; VEGF production was assayed by Elisa test and western blot analysis; sensitivity to VEGF was tested by thymidine incorporation. VEGF and its receptor KDR were expressed in B1647 and HEL, both as mRNAs and as proteins, while only KDR transcript was found in MO7 cells. Only B1647 and HEL cells showed a strong spontaneous proliferating activity. In fact, measurable amounts of VEGF were present in the unstimulated cell medium, thus suggesting an autocrine production of VEGF by B1647 and HEL cells, but not by MO7, which was inhibited in mRNA-silencing conditions. This production could not be further boosted by other growth factors, whereas it was inhibited by TGF-β1. Finally, analysis of She signal transduction proteins following stimulation with VEGF indicated that only p46 was tyrosine phosphorylated. These data indicate that leukemic cells may be capable of autocrine production of VEGF which, in turn, maintains cell proliferation, possibly mediated by She p46 phosphorylation.

Novel Evidence of PLC δ2 Involvement in the Regulation of the Differential Evolution of Aneurysms

The biological and molecular mechanisms which are responsible for the formation and possible evolution of human aneurysms are unknown. Previous investigations have pointed to the possible involvement of inositol specific-phospholipase C (PLC) in the mechanisms related to the formation or evolution of intracranial aneurysms, but, thus far, a relationship of one or more PLC isoforms with the biological signals influencing the fate of this lesion has not been demonstrated. The aim of this study was to investigate the expression, activity and possible modification of PLC isoforms in intracranial aneurysms in patients undergoing elective surgical repair after casual identification of unruptured aneurysms, or during emergency surgical repair of ruptured aneurysms. PLC and proliferating cell nuclear antigen (PCNA) expressions were detected by immunoistochemical analysis; PLC activity was obtained by measuring its hydrolytic activity on labelled PIP2; PKC activity was measured by total kinase activity assay. Results indicated no substantial differences between controls and aneurysms, with the only exception being PLC 52 which was nearly absent in controls and ruptured aneurysms, while strongly expressed and functionally active in almost all unruptured aneurysms. In addition, its expression always correlated with the proliferation cell marker PCNA, while its specific activity always correlated to PKC activity. PLC δ2 distribution, regulation and role in human tissues are still unknown Therefore, although preliminary, these data provide a novel insight into the signalling machinery influencing the aneurismal progression.

Omeprazole Induces Apoptosis in Jurkat Cells

We report for the first time a potent apoptotic effect of omeprazole (OM). Apoptosis was induced in Jurkat cells in a time and concentration-dependent mode. Caspase 3 and PARP were rapidly cleaved in response to OM, but apoptosis was only partially inhibited by the caspase 3 inhibitor DEVD-CHO. OM also induced an early lysosomal destabilization which increased progressively and was correlated with a parallel increase in apoptotic cells. The cysteine protease inhibitor E64d gave strong protection against apoptosis thus proving the involvement of lysosomal enzymes in OM-induced apoptosis whereas, it did not impede the caspase 3 cleavage. Instead ZVAD-fmk, a general caspase inhibitor, also able to inhibit cathepsin activity, protected cells completely from OM-induced apoptosis. It therefore seems that both caspases and cysteine cathepsins are involved in the execution stage of OM-induced apoptosis.

Infliximab Monotherapy for Refractory Psoriasis: Preliminary Results

Tumour necrosis factor (TNF)-alpha plays an important role in the pathogenesis of psoriasis. Infliximab is an anti-TNF-alpha chimeric monoclonal antibody, which is licensed for the treatment of rheumatoid arthritis and Crohn's disease. Some reports have shown the efficacy of infliximab, either in monotherapy or in combination with methotrexate, for the treatment of psoriatic arthropathy and psoriasis.

The efficacy and tolerability of infliximab monotherapy was evaluated in 29 patients with moderate to severe psoriasis, unresponsive to conventional treatments. Fourteen patients suffered from concomitant arthropathy. Patients received intravenous infliximab, 5mg/kg, at weeks 0, 2, and 6. After this 3-dose-induction regimen, patients were followed-up at monthly intervals and retreated with a single-dose infusion in case of relapse of signs and symptoms. Clinical assessment was performed using the psoriasis area and severity index (PASI) to monitor psoriasis activity; pruritus and joint pain were assessed on a scale of 0 to 3. A marked improvement of skin lesions and subjective symptoms was noted in the majority of patients; an excellent reduction of PASI score (⩾75%) was observed in 13.8% of cases at week 2, 71.4% at week 6 and 78.6% at week 10. During the follow-up period, some patients maintained satisfactory clinical results without requiring any additional infusions. In general, skin lesions showed a trend towards a more prolonged and sustained improvement as compared with subjective symptoms. Treatment was well tolerated and no serious adverse events occurred.

IL-6 Activates PI3K and PKCζ Signaling and Determines Cardiac Differentiation in Rat Embryonic H9c2 Cells

INTRODUCTION

IL-6 influences several biological processes, including cardiac stem cell and cardiomyocyte physiology. Although JAK-STAT3 activation is the defining feature of IL-6 signaling, signaling molecules such as PI3K, PKCs, and ERK1/2 are also activated and elicit different responses. Moreover, most studies on the specific role of these signaling molecules focus on the adult heart, and few studies are available on the biological effects evoked by IL-6 in embryonic cardiomyocytes.

AIM

The aim of this study was to clarify the biological response of embryonic heart derived cells to IL-6 by analyzing the morphological modifications and the signaling cascades evoked by the cytokine in H9c2 cells.

RESULTS

IL-6 stimulation determined the terminal differentiation of H9c2 cells, as evidenced by the increased expression of cardiac transcription factors (NKX2.5 and GATA4), structural proteins (α-myosin heavy chain and cardiac Troponin T) and the gap junction protein Connexin 43. This process was mediated by the rapid modulation of PI3K, Akt, PTEN, and PKCζ phosphorylation levels. PI3K recruitment was an upstream event in the signaling cascade and when PI3K was inhibited, IL-6 failed to modify PKCζ, PTEN, and Akt phosphorylation. Blocking PKCζ activity affected only PTEN and Akt. Finally, the overexpression of a constitutively active form of PKCζ in H9c2 cells largely mimicked the morphological and molecular effects evoked by IL-6.

CONCLUSIONS

This study demonstrated that IL-6 induces the cardiac differentiation of H9c2 embryonic cells though a signaling cascade that involves PI3K, PTEN, and PKCζ activities.

Novel evidence of ghrelin and growth hormone segretagogue receptor expression by human ocular tissues

AIM OF THE STUDY

The gastrointestinal peptide hormone ghrelin (Ghr) was discovered in 1999 as the endogenous ligand for the growth hormone secretagogue receptor (GHSR-1a). It is a pleiotropic peptide that modulates a wide spectrum of biological activities, such as growth hormone (GH) release, feeding stimulation, adiposity and cardiovascular actions. The presence of Ghr mRNA in the iris and ciliary body (CB) epithelium was recently demonstrated in animal models, where a possible myorelaxing effect on the iris muscles has been suggested. Based on these observations, the aim of our study was to investigate the Ghr and GHSR-1a expression and localization in the normal human eye.

MATERIAL

Five different ciliary body/iris samples from normal eyes were subjected to Western blot analysis. Immunohistochemical detection was performed on three enucleated eyes. Twenty aqueous humor (AqH) samples obtained from patients submitted to cataract surgery were analyzed with an ELISA for the presence of Ghr.

RESULTS

Ghr and GHSR-1a were co-expressed by the pigmented epithelium (PE) of the CB, by the retinal pigmented epithelium (RPE) and by the anterior limiting layer (ALL) of the iris. No reaction was detected at the subepithelial level in the ciliary or pupillae smooth muscle cells. The AqH samples were positive for the presence of Ghr.

CONCLUSION

This study provides the first evidence that Ghr and GHSR-1a are expressed in the human eye by specific cells. The understanding of the functional role of Ghr at the human eye level needs more efforts and investigation, but a hypothetical action on the GH retinal synthesis and/or on the circadian clock system could be suggested.

Interaction of aurintricarboxylic acid (ATA) with four nucleic acid binding proteins DNase I, RNase A, reverse transcriptase and Taq polymerase

In the investigation of interaction of aurintricarboxylic acid (ATA) with four biologically important proteins we observed inhibition of enzymatic activity of DNase I, RNase A, M-MLV reverse transcriptase and Taq polymerase by ATA in vitro assay. As the telomerase reverse transcriptase (TERT) is the main catalytic subunit of telomerase holoenzyme, we also monitored effect of ATA on telomerase activity in vivo and observed dose-dependent inhibition of telomerase activity in Chinese hamster V79 cells treated with ATA. Direct association of ATA with DNase I (K(d)=9.019 microM)), RNase A (K(d)=2.33 microM) reverse transcriptase (K(d)=0.255 microM) and Taq polymerase (K(d)=81.97 microM) was further shown by tryptophan fluorescence quenching studies. Such association altered the three-dimensional conformation of DNase I, RNase A and Taq polymerase as detected by circular dichroism. We propose ATA inhibits enzymatic activity of the four proteins through interfering with DNA or RNA binding to the respective proteins either competitively or allosterically, i.e. by perturbing three-dimensional structure of enzymes.

Nuclear protein kinase C-delta: a possible check-point of cell cycle progression

Protein kinase Cs (PKCs) belong to a serine/threonine kinase family, ubiquitously expressed and claimed to be involved in physiological processes including apoptosis, cell growth and differentiation. The question of the subcellular localization and activity of PKCs remains to be clarified. Here we report that nuclear PKC-delta cooperates to regulate the S-G2/M phase transition of cell cycle, apparently being associated to chromosome condensation and alignment on the metaphase plate.

Chemokines as markers for parasite-induced inflammation and tumors

Chemokines are a group of small secreted proteins (8-10 kDa) produced and released by a wide variety of cell types. They were originally described as mediators of leukocyte recruitment, which is essential in acute and chronic inflammation. They also play a critical role in many pathophysiological processes such as allergic responses, infections and autoimmune diseases, tumor growth and hematopoietic development. This review introduces the three supergene families of chemokines (CXC, CC and C) with emphasis on their important role in different states in humans and in animal models with parasitic diseases. The concentration of transcription and translation of the cytokines and chemokines in the parasitic diseases may be an important marker for evaluation of the inflammatory state.

Microenvironmental interactions and survival of CLL B-cells

Chronic Lymphocytic Leukemia (CLL) B cells display characteristics consistent with a defect in programmed cell death (apoptosis) and exhibit prolonged survival in vivo. When recovered from peripheral blood or lymphoid tissues from the patient and cultured in vitro, these malignant cells rapidly undergo spontaneous apoptosis. This observation suggests that the selective survival advantage enjoyed by CLL B-cells is not entirely autonomous, raising the possibility of manipulating CLL B-cell survival by iatrogenic means. The extended survival of the neoplastic B-cells creates a permissive soil on which oncogene activation, genetic instability and accumulation of gene mutations favoring disease progression can occur. In addition, such survival-promoting microenvironments can rescue leukemia cells from cytotoxic therapy, giving way to disease relapse. Survival of CLL B-cells is influenced by interactions with non-leukemia cells in the microenvironment of lymph nodes, marrow and other tissues. CLL B-cells have developed many different ways to escape undergoing apoptosis. These include: (a) expression of survival receptor as well as their ligands, giving rise to autocrine survival pathways which are leukemia cell specific; (b) defects in plasma membrane receptor cell signaling, triggered by death receptors such as Fas- and TRAIL; and (c) constitutively active survival signaling pathways such as NFkappaB and PI3K/Akt. Here we discuss some of the molecular mechanisms by which interaction with other cells and factors in the microenvironment provides survival advantages to CLL B-cells in specific in vivo niches, and we suggest some strategies for overcoming these anti-apoptotic mechanisms for improving treatment of CLL.