Novel higher-order epigenetic regulation of the Bdnf gene upon seizures.

Studies in cultured cells have demonstrated the existence of higher-order epigenetic mechanisms, determining the relationship between expression of the gene and its position within the cell nucleus. It is unknown, whether such mechanisms operate in postmitotic, highly differentiated cell types, such as neurons in vivo. Accordingly, we examined whether the intranuclear positions of Bdnf and Trkb genes, encoding the major neurotrophin and its receptor respectively, change as a result of neuronal activity, and what functional consequences such movements may have. In a rat model of massive neuronal activation upon kainate-induced seizures we found that elevated neuronal expression of Bdnf is associated with its detachment from the nuclear lamina, and translocation toward the nucleus center. In contrast, the position of stably expressed Trkb remains unchanged after seizures. Our study demonstrates that activation-dependent architectural remodeling of the neuronal cell nucleus in vivo contributes to activity-dependent changes in gene expression in the brain.

Possible role of complement factors and their inhibitors in the myocardial infarction: an immunohistochemical study.

Ongoing development of our civilization is accompanied by a marked increase of incidence of cardiovascular diseases and cardiovascular mortality. Ischemic heart disease with its extreme form - myocardial infarction - is one of the main problems of modern medicine. Despite much research devoted to this disease entity, its pathomechanism remains incompletely understood. Basing on research reports, more and more emphasis is put on immune reactions in the myocardium. Available literature lacks detailed studies examining the role of complement system and its inhibitors in the development and pathogenesis of myocardial infarction. Cells of ischemic myocardium were proven to become foreign antigens for the immune system of the patient's body. This results in complement activation of formation of so called membrane attacking complex that injures myocardial cells. By binding to its surface, it extends the myocardial destruction caused by the infarction itself. Results of immunochemistry studies presented in this paper have demonstrated the existence colocalization of complement components (C4d, C9) and membrane inhibitors (CD55, CD59) as well as soluble inhibitors (factor H) of the complement in the examined muscle tissue that underwent ischemic necrosis. Positive immunohistochemical reaction was found in the myocardial cells, intercellular matrix and blood vessels.

Prenyltransferases regulate CD20 protein levels and influence anti-CD20 monoclonal antibody-mediated activation of complement-dependent cytotoxicity.

Anti-CD20 monoclonal antibodies (mAbs) are successfully used in the management of non-Hodgkin lymphomas and chronic lymphocytic leukemia. We have reported previously that statins induce conformational changes in CD20 molecules and impair rituximab-mediated complement-dependent cytotoxicity. Here we investigated in more detail the influence of farnesyltransferase inhibitors (FTIs) on CD20 expression and antitumor activity of anti-CD20 mAbs. Among all FTIs studied, L-744,832 had the most significant influence on CD20 levels. It significantly increased rituximab-mediated complement-dependent cytotoxicity against primary tumor cells isolated from patients with non-Hodgkin lymphomas or chronic lymphocytic leukemia and increased CD20 expression in the majority of primary lymphoma/leukemia cells. Incubation of Raji cells with L-744,832 led to up-regulation of CD20 at mRNA and protein levels. Chromatin immunoprecipitation assay revealed that inhibition of farnesyltransferase activity was associated with increased binding of PU.1 and Oct-2 to the CD20 promoter sequences. These studies indicate that CD20 expression can be modulated by FTIs. The combination of FTIs with anti-CD20 mAbs is a promising therapeutic approach, and its efficacy should be examined in patients with B-cell tumors.

Influence of matrix metalloproteinase MMP-9 on dendritic spine morphology.

An increasing body of data has shown that matrix metalloproteinase-9 (MMP-9), an extracellularly acting, Zn(2+)-dependent endopeptidase, is important not only for pathologies of the central nervous system but also for neuronal plasticity. Here, we use three independent experimental models to show that enzymatic activity of MMP-9 causes elongation and thinning of dendritic spines in the hippocampal neurons. These models are: a recently developed transgenic rat overexpressing autoactivating MMP-9, dissociated neuronal cultures, and organotypic neuronal cultures treated with recombinant autoactivating MMP-9. This dendritic effect is mediated by integrin ß1 signalling. MMP-9 treatment also produces a change in the decay time of miniature synaptic currents; however, it does not change the abundance and localization of synaptic markers in dendritic protrusions. Our results, considered together with several recent studies, strongly imply that MMP-9 is functionally involved in synaptic remodelling.

Transplantation of mesenchymal stem cells into the skeletal muscle induces cytokine generation.

Mesenchymal stem cells due to the high proliferative potential, capacity of multilineage differentiation became a hope of regenerative medicine. However, the organism's response to the transplantation of MSCs is not fully elucidated. The aim of the present study was to evaluate the acute local tissue response to syngeneic MSCs administration into the muscle. Rat syngeneic MSCs were transplanted into the skeletal muscle and the tissue surrounding the injection site was collected after 24h. Analogous samples from untreated and PBS treated muscles served as controls. The analysis of genes expression using real-time PCR revealed significant up-regulation of proinflammatory cytokines: IL-1α, IL-1ß, IL-6 in MSCs treated muscles in comparison to the PBS group. The evaluation of protein concentration (ELISA) in collected samples showed that injection of MSCs caused significant elevation of IL-1ß. Immunofluorescent assessment of the tissue revealed infiltration of leukocytes and macrophages. Quantitative analysis of the samples immunostained for CD68 and CD43 antigens revealed that the number of phagocytes was significantly higher in MSC treated muscle when compared to the samples from PBS group. To conclude, the administration of mesenchymal stem cells into the muscle in syngeneic model induces the features of acute inflammation that affects cell engraftment.

CD44 is expressed in non-myelinating Schwann cells of the adult rat, and may play a role in neurodegeneration-induced glial plasticity at the neuromuscular junction.

CD44 is a multifunctional cell surface glycoprotein which regulates cell-cell and cell-matrix interactions in a variety of tissues. In particular, the protein was found to be expressed in glial cells of developing, but not adult, peripheral nerves, where it takes part in signaling mediated by ErbB class of receptors for neuregulins. Here, we demonstrate, using high resolution morphological methods, tissue fractionation and RT-PCR, that CD44 is strongly expressed in terminal Schwann cell (TSC) at the neuromuscular junction (NMJ) of the adult rat skeletal muscle. As CD44 is also expressed by Schwann cells of the non-myelinated Remak bundles of the proximal peripheral nerves, it appears to be a marker of non-myelinating Schwann cell subpopulation. The analysis of transgenic rats bearing a mutated superoxide-dismutase gene (SOD1(G93A)) causing familial amyotrophic lateral sclerosis (ALS) revealed that TSC activation and morphological plasticity at the NMJ, caused by ongoing denervation-reinnervation is associated with a strong increase in CD44 expression therein. Notably, CD44 immunoreactivity is present in fine axon-escheating processes of the glial cells that guide reinnervation. In addition, we found that both in normal and SOD1(G93A) muscle, CD44 expressed in TSC partially colocalizes with immunoreactivities of neuregulin receptors ErbB2 and ErbB3. The colocalization appears to reflect a physical interaction, as evidenced by co-immunoprecipitation and fluorescence resonance energy transfer (FRET) analysis between CD44 and ErbB3. Importantly, TSC activation upon ALS-like neurodegeneration results in significant increase in molecular proximity of CD44 and ErbB3, which may have an impact on glial plasticity at the NMJ.

The possible role of factor H in colon cancer resistance to complement attack.

A soluble complement inhibitor factor H (FH) and its splice variant factor H-like protein (FHL) have been recently discovered to play a major role in malignant cell escape from complement-mediated cytotoxicity in lung-, ovarian- and glia-derived neoplasms. The role of FH in colon cancer has not yet been examined. Here, we studied immunocytochemically FH/FHL expression in tumor samples derived from 40 patients, with both primary colon adenocarcinoma and metastatic foci in the liver. FH/FHL immunoreactivity was present in stroma of both primary and metastatic tumors, in virtually all patients. The cellular immunoreactivity was observed infrequently. Importantly, when analyzed quantitatively, FH/FHL immunoreactivity was significantly increased in liver metastases when compared with the primary sites. In addition, we have analyzed FH and FHL expression in 5 colon cancer cell lines: SW480, SW620, HCT116, HT-29 and Lovo. FH mRNA and FH secretion were observed in SW620 and HT-29 cells, whereas FHL was produced only by HT-29 cell-line. By confocal and electron microscopy, FH immunoreactivity was associated with the plasma membrane and intracellular vesicular structures. Finally, we have analyzed the role of FH in the susceptibility of SW620 colon cancer cells to complement-mediated damage. When FH function was blocked, using specific antibody, the cells became more susceptible to lysis. Taken together, our results suggest an important role of FH/FHL in colon cancer cells defense against complement-mediated cytotoxicity, and in metastatic process.

Statins impair antitumor effects of rituximab by inducing conformational changes of CD20.

BACKGROUND: Rituximab is used in the treatment of CD20+ B cell lymphomas and other B cell lymphoproliferative disorders. Its clinical efficacy might be further improved by combinations with other drugs such as statins that inhibit cholesterol synthesis and show promising antilymphoma effects. The objective of this study was to evaluate the influence of statins on rituximab-induced killing of B cell lymphomas. METHODS AND FINDINGS: Complement-dependent cytotoxicity (CDC) was assessed by MTT and Alamar blue assays as well as trypan blue staining, and antibody-dependent cellular cytotoxicity (ADCC) was assessed by a 51Cr release assay. Statins were found to significantly decrease rituximab-mediated CDC and ADCC of B cell lymphoma cells. Incubation of B cell lymphoma cells with statins decreased CD20 immunostaining in flow cytometry studies but did not affect total cellular levels of CD20 as measured with RT-PCR and Western blotting. Similar effects are exerted by other cholesterol-depleting agents (methyl-beta-cyclodextrin and berberine), but not filipin III, indicating that the presence of plasma membrane cholesterol and not lipid rafts is required for rituximab-mediated CDC. Immunofluorescence microscopy using double staining with monoclonal antibodies (mAbs) directed against a conformational epitope and a linear cytoplasmic epitope revealed that CD20 is present in the plasma membrane in comparable amounts in control and statin-treated cells. Atomic force microscopy and limited proteolysis indicated that statins, through cholesterol depletion, induce conformational changes in CD20 that result in impaired binding of anti-CD20 mAb. An in vivo reduction of cholesterol induced by short-term treatment of five patients with hypercholesterolemia with atorvastatin resulted in reduced anti-CD20 binding to freshly isolated B cells. CONCLUSIONS: Statins were shown to interfere with both detection of CD20 and antilymphoma activity of rituximab. These studies have significant clinical implications, as impaired binding of mAbs to conformational epitopes of CD20 elicited by statins could delay diagnosis, postpone effective treatment, or impair anti-lymphoma activity of rituximab.

Epstein-Barr Virus-Positive Diffuse Large B cell Lymphoma in the Experience of a Tertiary Medical Center in Poland.

The role of Epstein-Barr virus (EBV) in the biology and clinical characteristics of diffuse large B cell lymphoma (DLBCL) is still poorly defined. A new provisional entity EBV-positive DLBCL of the elderly has been described in Asian population. Its incidence and prognosis remains unknown in middle European patients. Clinical data and tissue samples were collected from 74 Caucasian patients with DLBCL, aged between 23 and 86 years, treated at a single institution. Lymphoma morphology was reassessed, laboratory procedures included in situ hybridization specific for EBV-encoded small RNAs (EBER), immunohistochemical staining for latent membrane protein and serological testing for EBV-specific antibodies. EBER staining revealed 12.2 % of EBV-positive cases, whereas 9.5 % were diagnosed as EBV-positive DLBCL of the elderly. Serologic EBV markers did not correlate with the presence of EBV in tissue samples (P > 0.10). Elderly EBV-positive cases had lower BCL-6 (P = 0.038) and higher CD30 (P = 0.049) expression and were characterized by higher progression risk (median time-to-progression 12.5 months vs not reached; P = 0.029) and a trend towards worse overall survival (median overall survival 24.5 months vs not reached; P = 0.059). EBV-positive DLBCL of the elderly occurs relatively frequently in Polish population and may be associated with inferior prognosis in comparison with DLBCL, not otherwise specified.

Effective photoimmunotherapy of murine colon carcinoma induced by the combination of photodynamic therapy and dendritic cells.

PURPOSE: The unique mechanism of tumor destruction by photodynamic therapy (PDT), resulting from apoptotic and necrotic killing of tumor cells accompanied by local inflammatory reaction and induction of heat shock proteins (HSPs), prompted us to investigate the antitumor effectiveness of the combination of PDT with administration of immature dendritic cells (DCs). EXPERIMENTAL DESIGN: Confocal microscopy and Western blotting were used to investigate the influence of PDT on the induction of apoptosis and expression of HSP expression in C-26 cells. Confocal microscopy and flow cytometry studies were used to examine phagocytosis of PDT-treated C-26 cells by DCs. Secretion of interleukin (IL)-12 was measured with ELISA. Cytotoxic activity of lymph node cells was evaluated in a standard (51)Cr-release assay. The antitumor effectiveness of PDT in combination with administration of DCs was investigated in in vivo model. RESULTS: PDT treatment resulted in the induction of apoptotic and necrotic cell death and expression of HSP27, HSP60, HSP72/73, HSP90, HO-1, and GRP78 in C-26 cells. Immature DCs cocultured with PDT-treated C-26 cells efficiently engulfed killed tumor cells, acquired functional features of maturation, and produced substantial amounts of IL-12. Inoculation of immature DCs into the PDT-treated tumors resulted in effective homing to regional and peripheral lymph nodes and stimulation of cytotoxic activity of T and natural killer cells. The combination treatment with PDT and administration of DCs produced effective antitumor response. CONCLUSIONS: The feasibility and antitumor effectiveness demonstrated in these studies suggest that treatment protocols involving the administration of immature DCs in combination with PDT may have clinical potential.

WITHDRAWN: Study coexistence albumin, fibrinogen and complement on surface blood vessels and placental.

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Antigenic profile of muscularis mucosae and muscularis propria of the urinary bladder.

BACKGROUND: Differentiation between the muscularis mucosae (MM) and muscularis propria (MP) of the bladder remains challenging. OBJECTIVE: To identify MM- and MP-specific antigens that could be of potential value for staging of urothelial carcinoma in a pilot study. METHOD: The expression of 12 protein antigens in 11 human bladder specimens was examined. There were 5 post radical cystectomy specimens and 6 normal bladder autopsy specimens. Antibodies against actin, caldesmon, type IV collagen, cytokeratin, desmin, elastin, fibronectin, filamin, laminin, miotilin, smoothelin, and vimentin were used. Slides were stained with immunohistochemical reagents and assessed using light microscopy. The intensity of the immune reaction within MM and MP was evaluated in a four-level scale as negative and weakly, moderately or strongly positive. RESULTS: The presence of MM was noticed in 63.6% of specimens. The expression of desmin, filamin, and smoothelin was stronger within MP compared to MM in all cases. Stronger reaction with anti-type IV collagen antibodies was noticed within MP in 80% of the cases. In the whole study group, the expression of vimentin was stronger within MM than MP. CONCLUSIONS: MM and MP cells are of different antigenic characteristics. This can be used in the microscopic diagnostics of selected cases. The results need to be validated in a series of specimens from transurethral resection.

Up-regulation of CacyBP/SIP during rat breast cancer development.

BACKGROUND: CacyBP/SIP (calcyclin binding protein/Siah-1 interacting protein) was originally discovered in Ehrlich ascities tumor cells but was later found also in many different tumors. METHODS: To better understand the function of CacyBP/SIP in carcinogenesis, we used immunohistochemistry, Western blotting, and RT-PCR assays to study the distribution and level of CacyBP/SIP in mammary tissues after tumor induction in rat with DMBA [(dimethylbenz[a]anthracene)]. Application of such a model allowed us to monitor changes in CacyBP/SIP level during development of breast cancer. RESULTS: We found that both the protein and mRNA levels of CacyBP/SIP gradually increased in pathologically changed tissues and were highest in tumors taken 8 weeks after DMBA treatment. Similar changes as for CacyBP/SIP were detected in the level of ß-catenin. CONCLUSION: Increase in CacyBP/SIP expression during development of breast cancer, observed early in the mammary tissues with only minimal pathological changes, might suggest an important role of this protein in the process of carcinogenesis.

The study of the protein complement in myocardial infarction.

BACKGROUND: Activation of the complement system during myocardial ischemia and reperfusion results in its injury by multiple processes. The aim of this study was to evaluate contribution of innate, humoral mechanisms of nonspecific immune response in the myocardium subjected to infarction. Complement components and inhibitors were analyzed. MATERIALS AND METHODS: Myocardial specimens from the archives of Chair and Department of Pathology, Medical University of Warsaw from 2010 to 2013, were used in the study. The examined proteins were evaluated using immunohistochemistry and immunofluorescence techniques. Tissues from 36 men and 14 women, mean age 65.02 ± 14.65, were used in the study. The control group comprised healthy myocardial tissue collected from 10 subjects. RESULTS: Statistical analysis of IHC reaction for proteins and inhibitors of the complement system and membrane attack complex demonstrated markedly higher immunoreactivity level in the myocardium with ischemic necrosis versus healthy myocardial tissue. A correlation analysis demonstrated statistically significant positive correlation between the examined proteins and inhibitors of the complement system and protectin and membrane attack complex. A significant correlation was not found between immunoreactivity of the examined proteins and clinical and morphological parameters of the analyzed cases. CONCLUSIONS: Studies have shown that of the complement proteins presence on the surface of the myocardium subjected to ischemic destruction exacerbate.

Deleted in liver cancer 1 expression and localization in hepatocellular carcinoma tissue sections.

The deleted in liver cancer (DLC) protein family is composed of proteins that are hypothesized to function predominantly by regulating the activity of the small GTPases. The aim of the present study was to determine the expression and exact localization of DLC1 in hepatocellular carcinoma (HCC) tissue sections. In two types of HCC tissues, typical and fibrolamellar, immunohistochemical and immunofluorescent analysis were performed to assess DLC1 immunoreactivity. Additionally, the DLC1 gene status was determined by the fluorescence in situ hybridization. According to the observations, DLC1 is often lost in cancer cells; however, it can remain within the stromal component of tumor sections. The DLC1 immunoreactivity was particularly noticeable within the capsules surrounding the tumor masses. It was found that the DLC1 gene was deleted in 52% of HCC cases. In addition, the hemizygous deletion was observed to be independent of the HCC subtype. The results indicate that although the loss of DLC1 is a common step during hepatocarcinogenesis, this protein may be present in the tumor microenvironment.

Loss of the orphan nuclear receptor SHP is more pronounced in fibrolamellar carcinoma than in typical hepatocellular carcinoma.

Hepatocellular carcinoma (HCC) remains a major problem in oncology. The molecular mechanisms which underlie its pathogenesis are poorly understood. Recently the Small Heterodimer Partner (SHP), an orphan nuclear receptor, was suggested to be involved as a tumor suppressor in hepatocellular carcinoma development. To date, there are no such studies regarding fibrolamellar carcinoma, a less common variant of HCC, which usually affects young people and displays distinct morphological features. The aim of our project was to evaluate the SHP levels in typical and fibrolamellar hepatocellular carcinoma with respect to the levels of one of the cell cycle regulators, cyclin D1. We assessed the immunoreactivity levels of SHP and cyclin D1 in 48 typical hepatocellular carcinomas, 9 tumors representing the fibrolamellar variant, 29 non malignant liver tissues and 7 macroregenerative nodules. We detected significantly lower SHP immunoreactivity in hepatocellular carcinoma when compared to non malignant liver tissue. Moreover, we found that SHP immunoreactivity is reduced in fibrolamellar carcinoma when compared to typical hepatocellular carcinoma. We also found that SHP is more commonly lost in HCC which arises in the liver with steatosis. The comparison between the cyclin D1 and SHP expression revealed the negative correlation between these proteins in the high grade HCC. Our results indicate that the impact of loss of SHP protein may be even more pronounced in fibrolamellar carcinoma than in a typical form of HCC. Further investigation of mechanisms through which the loss of SHP function may influence HCC formation may provide important information in order to design more effective HCC therapy.

Important role of matrix metalloproteinase 9 in epileptogenesis.

Temporal lobe epilepsy (TLE) is a devastating disease in which aberrant synaptic plasticity plays a major role. We identify matrix metalloproteinase (MMP) 9 as a novel synaptic enzyme and a key pathogenic factor in two animal models of TLE: kainate-evoked epilepsy and pentylenetetrazole (PTZ) kindling-induced epilepsy. Notably, we show that the sensitivity to PTZ epileptogenesis is decreased in MMP-9 knockout mice but is increased in a novel line of transgenic rats overexpressing MMP-9. Immunoelectron microscopy reveals that MMP-9 associates with hippocampal dendritic spines bearing asymmetrical (excitatory) synapses, where both the MMP-9 protein levels and enzymatic activity become strongly increased upon seizures. Further, we find that MMP-9 deficiency diminishes seizure-evoked pruning of dendritic spines and decreases aberrant synaptogenesis after mossy fiber sprouting. The latter observation provides a possible mechanistic basis for the effect of MMP-9 on epileptogenesis. Our work suggests that a synaptic pool of MMP-9 is critical for the sequence of events that underlie the development of seizures in animal models of TLE.

[The effect of retinoic acid on primary cultures of human pheochromocytoma cells]. / Wplyw kwasu retinowego na komórki pheochromocytoma.

INTRODUCTION: Retinoic acid is a regulator of gene expression which, by binding to its nuclear receptor, determines the degree of differentiation in multiple cancer cell types. On the basis of this capability it was introduced, e.g. in the therapy of neuroblastoma. In cells derived from neural crest, such as neuroblastoma cells, retinoic acid initiates differentiation into neurons. This substance acts in a similar way on a rat pheochromocytoma cell line PC12. The aim of our work was to examine the influence of retinoic acid on the phenotype of human pheochromocytoma cells in primary culture. MATERIAL AND METHODS: Observations were made on two primary cultures isolated from human pheochromocytoma. Cells were grown in RPMI1640 medium supplemented with 10% foetal bovine serum. Subsequently, the cultures were treated with 100 mMol retinoic acid for three-days. An evaluation of the phenotype change was performed by estimating the expression levels of F-actin, MAP-2 protein, and chromogranin, with the use of a confocal microscopy. RESULTS: The introduction of retinoic acid into the culture caused an increase in the F-actin level and its redistribution in the form of stress fibers. Simultaneously, the cells changed their shape, generating more processes. No change was detected in the expression level of neuroendocrine markers: MAP-2 and chromogranin. CONCLUSIONS: Retinoic acid appears to have an influence on some phenotype parameters of human pheochromocytoma cells. Further work is needed to determine the molecular mechanisms of this process, and to evaluate thoroughly the benefits of introducing retinoic acid into therapy of pheochromocytoma tumors.