Analysis of Reelin signaling and neurodevelopmental trajectory in primary cultured cortical neurons with RELN deletion identified in schizophrenia.

Reelin, an extracellular matrix protein, is secreted by Cajal-Retzius cells and plays crucial roles in the development of brain structures and neuronal functions. Reductions in Reelin cause the brain dysfunctions associated with mental disorders, such as schizophrenia. A recent genome-wide copy number variation analysis of Japanese schizophrenia patients identified a novel deletion in RELN encoding Reelin. To clarify the pathophysiological role of the RELN deletion, we developed transgenic mice carrying the RELN deletion (Reln-del) and found abnormalities in their brain structures and social behavior. In the present study, we performed an in vitro analysis of Reelin expression, intracellular Reelin signaling, and the morphology of primary cultured cortical neurons from wild-type (WT) and Reln-del mice. Reelin protein levels were lower in Reln-del neurons than in WT neurons. Dab1 expression levels were significantly higher in Reln-del neurons than in WT neurons, suggesting that Reelin signaling was decreased in Reln-del neurons. Reelin was mainly expressed in γ-aminobutyric acid (GABA)-ergic inhibitory neurons, but not in parvalbumin (PV)-positive neurons. A small proportion of Ca2+/calmodulin-dependent protein kinase II α subunit (CaMKIIα)-positive excitatory neurons also expressed Reelin. In comparisons with WT neurons, significant decreases were observed in neurite lengths and branch points as well as in the number of postsynaptic density protein 95 (PSD95) immunoreactive puncta in Reln-del neurons. A disintegrin and metalloproteinase with thrombospondin motifs-3 (ADAMTS-3) is a protease that inactivates Reelin by cleavage at the N-t site. The knockdown of ADAMTS-3 by short hairpin RNAs suppressed Reelin cleavage in conditioned medium and reduced Dab1 expression, indicating that Reelin signaling was enhanced in the primary cultured cortical neurons of WT and heterozygous Reln-del. Accordingly, the inhibition of ADAMTS-3 may be a potential candidate in the clinical treatment of schizophrenia by enhancing Reelin signaling in the brain.

Schizophrenia risk candidate EGR3 is a novel transcriptional regulator of RELN and regulates neurite outgrowth via the Reelin signal pathway in vitro.

Schizophrenia is a severe psychiatric disorder with a strong hereditary component that affects approximately 1% of the world's population. The disease is most likely caused by the altered expression of a number of genes that function at the level of biological pathways or gene networks. Transcription factors (TF) are indispensable regulators of gene expression. EGR3 is a TF associated with schizophrenia. In the current study, DNA microarray and ingenuity pathway analyses (IPA) demonstrated that EGR3 regulates Reelin signaling pathway in SH-SY5Y cells. ChIP and luciferase reporter studies confirmed that EGR3 directly binds to the promoter region of RELN thereby activating RELN expression. The expression of both EGR3 and RELN was decreased during neuronal differentiation induced by retinoic acid (RA) in SH-SY5Y cells, and EGR3 over-expression reduced neurite outgrowth which could be partially reversed by the knockdown of RELN. The expression levels of EGR3 and RELN in peripheral blood of subjects with schizophrenia were found to be down-regulated (compared with healthy controls), and were positively correlated. Furthermore, data mining from public databases revealed that the expression levels of EGR3 and RELN were presented a positive correlation in post-mortem brain tissue of subjects with schizophrenia. Taken together, this study suggests that EGR3 is a novel TF of the RELN gene and regulates neurite outgrowth via the Reelin signaling pathway. Our findings contribute to the understanding of the regulatory role of EGR3 in the pathophysiology and molecular mechanisms of schizophrenia, and potentially to the development of new therapies and diagnostic biomarkers for the disorder.

Tumoral Expression of CD166 in Human Esophageal Squamous Cell Carcinoma: Implications for Cancer Progression and Prognosis.

Accumulating data showed that cancer stem cells (CSCs) identified by cell surface markers contribute to the initiation, progression, and prognosis of human cancers. In this study, the expression of CSC candidates CD166, CD44, and Lgr5 in 65 cases of esophageal squamous cell carcinoma (ESCC) and 16 cases of control esophageal tissues were examined with immunohistochemistry (IHC). The correlation between tumoral expression levels of these CSC candidates and clinicopathological variables was analyzed. IHC results showed that the expression of CD166 in esophageal control tissues was completely negative, but it was in 87.69% (57/65) ESCC tissues. The expression of CD44 and Lgr5 did not differ between esophageal control tissues and ESCC tissues (p > 0.05). In addition, there were not correlations found among the expression levels of CD166, CD44, and Lgr5 in ESCC tissues. Clinicopathological analysis revealed that the tumoral expression level of CD166 correlated with lymph node involvement and TNM staging in patients with ESCC, and lower tumoral expression of CD44 was found in patients with advanced TNM staging. Kaplan-Meier survival curves suggested that expression level of CD166 appeared to have a negative impact on overall survival rate after surgery in patients with ESCC. Such impact was not found in other two CSC candidates. The authors therefore conclude that CD166 is a potential prognostic biomarker and correlates with advanced progression features in patients with ESCC.

Expression of synaptic proteins in the hippocampus is modulated by neonatal oxytocin treatment.

An alteration of oxytocin signaling during postnatal maturation of the brain could be associated with etiology of neurodevelopmental disorders among them autism. The aim of the present study was to examine the role of oxytocin in the regulation of expression of selected cell-adhesion molecules and scaffolding proteins in the hippocampus in early rat development. Oxytocin treatment (1 mg/ml, i.p., 50 µl/pup) at postnatal days P2-P3 resulted in the reduction of Neuroligin 3 gene expression, and was accompanied by lower SHANK1 and SHANK3 mRNA levels in the hippocampus at P5 day. Immunostaining revealed a clear trend for the lower density of Neuroligin 3 positive cells in the hippocampus and this trend has been significant in the CA3 hippocampal area. The significantly lower Neurexin 2ß mRNA levels were observed in response to oxytocin treatment, with no effect seen in the Neurexin 2α gene expression. No change has been observed in the gene expression of Neuroligin 1 and Neuroligin 2. Oxytocin induced an increase in the mRNA levels of Neuron-Specific Enolase (NSE) and a decrease in the mRNA levels of glial fibrillary acid protein (GFAP) - marker of astrocytes. Incubation of primary neuronal cells with oxytocin (1 µM, 48 h) stimulated a proliferation of NSE-positive cells. These results suggest that synaptic proteins could be under control of oxytocin in early stages of brain development. The changes of cell-adhesion molecule and scaffolding protein levels might be linked to the modulation of number of neuronal cells.

Epigenetic mechanisms underlying the effects of triptolide and tripchlorolide on the expression of neuroligin-1 in the hippocampus of APP/PS1 transgenic mice.

Context: Neuroligin-1 (NLGN1) is a cell adhesion protein located on the excitatory postsynaptic membrane. ß-Amyloid (Aß)-induced neuroinflammation decreases NLGN1 expression through epigenetic mechanisms. Triptolide (T10) and tripchlorolide (T4) exert protective effects on synapses in Alzheimer's disease (AD) mice, but the mechanisms remain unclear. Objective: The effects of T10 and T4 on hippocampal NLGN1 expression in AD mice and the epigenetic mechanisms were assessed using chromatin immunoprecipitation and methylated DNA immunoprecipitation. Materials and methods: Sixty APP/PS1 transgenic mice were randomly divided into an AD model group, a T10-treated group and a T4-treated group (n = 20); 20 wild-type littermates served as the control group. APP/PS1 transgenic mice were intraperitoneally injected with T10 (0.1 mg/kg) and T4 (25 µg/kg) once per day for 60 days. NLGN1 expression was examined using western blotting and quantitative PCR. Results: T10 and T4 increased the levels of the NLGN1 protein and mRNA in hippocampus of AD mice. T10 and T4 inhibited the binding of HDAC2 (p< 0.01) and MeCP2 (p< 0.01 and p< 0.05, respectively) to the NLGN1 promoter, and cytosine methylation (1.2305 ± 0.1482/1.2554 ± 0.3570 vs. 1.6578 ± 0.1818, p< 0.01) at the NLGN1 promoter in the hippocampus of AD mice. T10 and T4 increased the level of acetylated histone H3 (0.7733 ± 0.1611/0.8241 ± 0.0964 vs. 0.5587 ± 0.0925, p< 0.01) at the NLGN1 promoter in the hippocampus of AD mice. Conclusions: T10 and T4 may increase hippocampal NLGN1 expression in AD mice through epigenetic mechanisms, providing a new explanation for the mechanism underlying the protective effects of T10 and T4 on synapses.

Intron polymorphisms of MAGI-1 and ACSF2 and effects on their expression in different goose breeds.

The goose is one of the most important waterfowl, having lowing laying rate. Previous studies have shown the SNPs in the introns of MAGI-1 (Record-106975) and ACSF2 (Record-106582) significantly associated with egg production in geese. However, the mechanism of those SNPs influencing egg production remains unclear. In this study, the three goose breeds (Yangzhou geese, Zhedong white geese, and Carlos geese) with obviously different egg production were selected, and the allele frequency distribution and functions of those SNPs were investigated. The results suggested that the allele frequency distribution of ACSF2 was significantly different among the three goose breeds (χc2 = 92.377, Pc = 2.29 × 10-22), with the C allele appearing at frequencies of 0.29 in the Yangzhou geese and 0.94 in the Carlos geese. In contrast, the allele frequencies of MAGI-1 were not significantly different among the different goose breeds. Quantitative Reverse Transcription PCR (qRT-PCR) showed that the expression of MAGI-1 with the AG genotype individuals was significantly higher than those of the AA and GG genotype. For ACSF2, the CC genotype had significantly higher expression than both the AC genotype and the AA genotype. The luciferase reporter analysis revealed that the site-directed mutation ACSF2 (A>C) significantly drove the expression activity. Further analysis suggested that the mutation altered the binding site of the transcription factor BARHL2. Binding of BARHL2 to the ACSF2 intron was confirmed by electrophoretic mobility shift assay (EMSA) analysis. Thus, our findings revealed the A>C mutation of ACSF2 (Record-106582) could promote the expression by regulating the binding of BARHL2, resulting in differences in egg performance, which provided molecular insights into the effect of the polymorphism in ACSF2 on egg performance in geese.

Reelin and aromatase cooperate in ovarian follicle development.

Reelin plays an important role in cerebral cortex development and synaptogenesis. In the hippocampus, the neurosteroid estrogen affects reelin expression. In this study we tested a potential crosstalk between estradiol and reelin, thus the possibility of a reelin-induced activation of the estradiol synthesizing enzyme aromatase. As a model system, we used ovaries, which express reelin and are a major source of estradiol. We found that in wild-type mice, reelin and aromatase are expressed in granulosa cells of growing follicles. The expression of reelin varies with the estrus cycle and is highest shortly before ovulation, when estradiol serum levels are at their maximum. In ovaries of reelin-deficient reeler mice, aromatase mRNA and protein are significantly reduced, as evidenced by real-time PCR, western blot analysis, and quantitative immunohistochemistry in granulosa cells of preovulatory follicles. In line with reduced estradiol synthesis, ovarian estrus cycle length is prolonged in reeler mice. Most importantly, treating cultured granulosa cells with recombinant reelin results in significant upregulation of aromatase mRNA and protein and increased secretion of estradiol into the supernatant. Our data provide evidence of a local increase of aromatase expression by reelin. Regarding reproduction, this crosstalk may contribute to follicular stability and counteract luteinization in ovaries.

Yif1 associates with Yip1 on Golgi and regulates dendrite pruning in sensory neurons during Drosophila metamorphosis.

Pruning that selectively removes unnecessary neurites without causing neuronal death is essential for sculpting the mature nervous system during development. In Drosophila, ddaC sensory neurons specifically prune their larval dendrites with intact axons during metamorphosis. However, the important role of endoplasmic reticulum (ER)-to-Golgi transport in dendrite pruning remains unknown. Here, in a clonal screen, we have identified Yif1, an uncharacterized Drosophila homolog of Yif1p that is known to be a regulator of ER-to-Golgi transport in yeast. We show that Yif1 is required for dendrite pruning of ddaC neurons but not for apoptosis of ddaF neurons. We further identify that the Yif1-binding partner Yip1 is also crucial for dendrite pruning. Yif1 forms a protein complex with Yip1 in S2 cells and ddaC neurons. Yip1 and Yif1 colocalize on ER/Golgi and are required for the integrity of Golgi apparatus and outposts. Moreover, we show that two GTPases, Rab1 and Sar1, which are known to regulate ER-to-Golgi transport, are essential for dendrite pruning of ddaC neurons. Finally, our data reveal that ER-to-Golgi transport promotes endocytosis and downregulation of the cell-adhesion molecule Neuroglian and thereby dendrite pruning.

An Attractive Reelin Gradient Establishes Synaptic Lamination in the Vertebrate Visual System.

A conserved organizational and functional principle of neural networks is the segregation of axon-dendritic synaptic connections into laminae. Here we report that targeting of synaptic laminae by retinal ganglion cell (RGC) arbors in the vertebrate visual system is regulated by a signaling system relying on target-derived Reelin and VLDLR/Dab1a on the projecting neurons. Furthermore, we find that Reelin is distributed as a gradient on the target tissue and stabilized by heparan sulfate proteoglycans (HSPGs) in the extracellular matrix (ECM). Through genetic manipulations, we show that this Reelin gradient is important for laminar targeting and that it is attractive for RGC axons. Finally, we suggest a comprehensive model of synaptic lamina formation in which attractive Reelin counter-balances repulsive Slit1, thereby guiding RGC axons toward single synaptic laminae. We establish a mechanism that may represent a general principle for neural network assembly in vertebrate species and across different brain areas.

Reduced mannosidase MAN1A1 expression leads to aberrant N-glycosylation and impaired survival in breast cancer.

BACKGROUND: Alterations in protein glycosylation have been related to malignant transformation and tumour progression. We recently showed that low mRNA levels of Golgi alpha-mannosidase MAN1A1 correlate with poor prognosis in breast cancer patients. METHODS: We analysed the role of MAN1A1 on a protein level using western blot analysis (n=105) and studied the impact of MAN1A1-related glycosylation on the prognostic relevance of adhesion molecules involved in breast cancer using microarray data (n=194). Functional consequences of mannosidase inhibition using the inhibitor kifunensine or MAN1A1 silencing were investigated in breast cancer cells in vitro. RESULTS: Patients with low/moderate MAN1A1 expression in tumours showed significantly shorter disease-free intervals than those with high MAN1A1 levels (P=0.005). Moreover, low MAN1A1 expression correlated significantly with nodal status, grading and brain metastasis. At an mRNA level, membrane proteins ALCAM and CD24 were only significantly prognostic in tumours with high MAN1A1 expression. In vitro, reduced MAN1A1 expression or mannosidase inhibition led to a significantly increased adhesion of breast cancer cells to endothelial cells. CONCLUSIONS: Our study demonstrates the prognostic role of MAN1A1 in breast cancer by affecting the adhesive properties of tumour cells and the strong influence of this glycosylation enzyme on the prognostic impact of some adhesion proteins.

Expression of ALCAM (CD166) and PD-L1 (CD274) independently predicts shorter survival in malignant pleural mesothelioma.

Diffuse malignant mesothelioma of the pleura is a highly aggressive tumor typically associated with short survival. ALCAM (CD166), a type I transmembrane protein, is a member of the immunoglobulin superfamily. In normal cells, ALCAM regulates physiological processes such as angiogenesis and immune response. In cancer, it is associated with neoplastic progression, including invasion, migration, and metastasis. Furthermore, ALCAM is considered one of the cancer stem cell markers such as ALDH1 (ALDH1A1) and SALL4. The PD-L1 (CD274)/PD-1 (PDCD1, CD279) pathway is crucial for the modulation of immune responses in normal cells. Nevertheless, pathologic activation of the PD-L1/PD-1 pathway participates in immune evasion by tumor cells. Many PD-L1-expressing tumor cells have been identified in different types of cancer, including malignant mesothelioma. In this study, 175 well-characterized primary diffuse pleural mesotheliomas, including the epithelioid (n = 148), biphasic (n = 15), and sarcomatoid (n = 12) histotypes, were evaluated immunohistochemically for cancer stem cell markers (ALCAM, ALDH1, and SALL4) and PD-L1 expression. Twenty-five percent of the mesotheliomas (43/175) expressed ALCAM, whereas ALDH1 and SALL4 positivity was seen in 1% to 2% of cases. Thirty-three percent of the analyzed tumors (57/175) contained PD-L1-positive cells. Overall survival was significantly decreased in the cohort of patients with ALCAM- or PD-L1-positive tumors (both P < .01). Furthermore, the multivariate Cox hazards regression analysis identified ALCAM and PD-L1 (both P < 0.01) as potential independent risk factors. Thus, a combination of these 2 markers might be useful for prognostication and planning the treatment of patients with malignant pleural mesothelioma.

Down-regulation of fibronectin and the correlated expression of neuroligin in hirschsprung disease.

AIM: The goal of this study was to investigate the expression of fibronectin (FN) and the correlated abundance of neuroligins (NLs) in the enteric nervous system (ENS) and to find a novel diagnostic marker in the serum of Hirschsprung disease (HSCR) patients. METHODS: The expression levels of FN, neuroligin-1 and neuroligin-2 were detected in 114 children with or without HSCR. The expression and localization of the NLs and FN were assessed morphologically by immunohistochemical staining. Western blot analysis and real-time fluorescence quantitative PCR (qPCR) were performed to examine the correlated expression of the NLs and FN in aganglionic, transitional, and normal ganglionic colon tissues. An enzyme-linked immunosorbent assay (ELISA) was performed to evaluate and compare serum FN levels between HSCR and non-HSCRand between long-type HSCR and short-type HSCR. RESULTS: These studies showed that both neuroligin-1 and neuroligin-2 were expressed at low levels in aganglionic segments and at intermediate levels in transitional segments compared to their high level of expression in normal tissue. In contrast, FN expression was negatively correlated, with expression in these three samples transitioning from highest to lowest. The serum FN level was higher in HSCR than in non-HSCR, but no significant difference between short-type HSCR and long-type HSCR was observed. CONCLUSION: FN affects the expression of both neuroligin-1 and neuroligin-2 in HSCR, which may lead to the hypoplasia of ganglion cells in the ENS. This correlation may play a key role in the pathogenesis, diagnosis, or classification of HSCR.

An immunoaffinity-based method for isolating ultrapure adult astrocytes based on ATP1B2 targeting by the ACSA-2 antibody.

Astrocytes are a major cell type in the mammalian CNS. Astrocytes are now known to play a number of essential roles in processes including synapse formation and function, as well as blood-brain barrier formation and control of cerebral blood flow. However, our understanding of the molecular mechanisms underlying astrocyte development and function is still rudimentary. This lack of knowledge is at least partly due to the lack of tools currently available for astrocyte biology. ACSA-2 is a commercially available antibody originally developed for the isolation of astrocytes from young postnatal mouse brain, using magnetic cell-sorting methods, but its utility in isolating cells from adult tissue has not yet been published. Using a modified protocol, we now show that this tool can also be used to isolate ultrapure astrocytes from the adult brain. Furthermore, using a variety of techniques (including single-cell sequencing, overexpression and knockdown assays, immunoblotting, and immunohistochemistry), we identify the ACSA-2 epitope for the first time as ATP1B2 and characterize its distribution in the CNS. Finally, we show that ATP1B2 is stably expressed in multiple models of CNS injury and disease. Hence, we show that the ACSA-2 antibody possesses the potential to be an extremely valuable tool for astrocyte research, allowing the purification and characterization of astrocytes (potentially including injury and disease models) without the need for any specialized and expensive equipment. In fact, our results suggest that ACSA-2 should be a first-choice method for astrocyte isolation and characterization.

Reelin expression in human liver of patients with chronic hepatitis C infection.

Reelin is a secreted extracellular glycoprotein that plays a critical role during brain development. Several studies have described Reelin expression in hepatic stellate cells of the human liver. In order to investigate the possible role of Reelin in the process of hepatic fibrogenesis, in this study we investigated Reelin expression in the liver tissue of patients infected with the Hepatitis C Virus (HCV). On this basis, Reelin expression was analysed by immunohistochemistry during liver biopsies of 81 patients with HCV-related chronic hepatitis. A Knodell score was used to stage liver fibrosis. Hepatic stellate cells/myofibroblast immunohistochemical markers (CRBP-1, alpha-SMA) were also evaluated. As further confirmed by co-localization experiments (Reelin +CRBP-1), Reelin protein was expressed by hepatic stellate cells/myofibroblasts, and a significant positive correlation was found between Reelin expression and the stage of liver fibrosis (P=0.002). Moreover, Reelin correlated with CRBP-1 positive cells (P=0.002), but not with alpha-SMA, suggesting that Reelin should not be regarded as a marker of hepatic stellate cells/myofibroblasts differentiation but rather as a functional protein expressed during some phases of liver fibrosis. Furthermore, Disabled-1 (Dab1), a Reelin adaptor protein, was expressed in cells of ductular reaction suggesting a paracrine role for Reelin with regards these elements. In conclusion, Reelin was expressed by human hepatic stellate cells/myofibroblasts and the number of these cells increased significantly in the lobule as the liver fibrosis progressed, suggesting a role for Reelin in the activation of hepatic stellate cells/myofibroblasts during liver injury. Reelin may potentially be incorporated into liver injury evaluations in combination with other histological data.

Astrocyte-induced Reelin expression drives proliferation of Her2+ breast cancer metastases.

Breast cancer metastasis to the brain develops after a clinical latency of years to even decades, suggesting that colonization of the brain is the most challenging step of the metastatic cascade. However, the underlying mechanisms used by breast cancer cells to successfully colonize the brain's microenvironment remain elusive. Reelin is an archetypal extracellular glycoprotein that regulates migration, proliferation, and lamination of neurons. It is epigenetically silenced in various cancers, and its expression in multiple myelomas is linked to poor patient survival. We found that Reelin expression was low in primary breast cancer tissue. However, its expression was significantly higher in Her2+ breast cancers metastasizing to the brain. In particular, Reelin was highly expressed in the tumor periphery adjacent to surrounding astrocytes. This augmented Reelin expression was seen in Her2+ metastases, but not in triple negative (TN) primary tumors or in TN breast to brain metastasis cells co-cultured with astrocytes. Furthermore, the elevated expression was sustained in Her2+ cells grown in the presence of the DNA methyltransferase inhibitor 5-azacytidine, indicating epigenetic regulation of Reelin expression. The relative growth and rate of spheroids formation derived from Her2+ primary and BBM cells co-cultured with astrocytes were higher than those of TN primary and BBM cells, and knockdown of both Reelin and Her2 suppressed the astrocyte-induced growth and spheroid forming ability of Her2+ cells. Collectively, our results indicate that within the neural niche, astrocytes epigenetically regulate Reelin expression and its interaction with Her2 leading to increased proliferation and survival fitness.

Abundance and Significance of Neuroligin-1 and Neurexin II in the Enteric Nervous System of Embryonic Rats.

Aim. To investigate the abundance of neuroligin-1 and neurexin II in the enteric nervous system (ENS) of rats on different embryonic days and to explore their potential significance. Methods. The full-thickness colon specimens proximal to the ileocecal junction of rats on embryonic days 16, 18, and 20 and of newborns within 24 hours (E16, E18, E20, and Ep0) were studied, respectively. qRT-PCR was applied for detecting the expressions of neuroligin-1 and neurexin II on mRNA, and western blotting was employed for detecting their further expressions on the whole tissue. Finally, the histological appearance of neuroligin-1 and neurexin IIα was elucidated using immunohistochemical staining. Results. qRT-PCR showed that the neuroligin-1 and neurexin II mRNA expressions of groups E16, E18, E20, and Ep0 increased gradually with the growth of embryonic rats (P < 0.05). Western blotting confirmed the increasing tendency. In immunohistochemical staining, proteins neuroligin-1 and neurexin IIα positive cells concentrated mostly in the myenteric nerve plexus of the colon and their expressions depend on the embryonic time. Conclusion. Neuroligin-1 and neurexin II were both expressed in the ENS and have temporal correlation with the development of ENS, during which neuronal intestinal malformations (NIM) may occur due to their disruptions and consequent abnormal ENS development.

The Effects of Alpha Boswellic Acid on Reelin Expression and Tau Phosphorylation in Human Astrocytes.

Reelin is an extracellular glycoprotein which contributes to synaptic plasticity and function of memory in the adult brain. It has been indicated that the Reelin signaling cascade participates in Alzheimer's disease (AD). Besides the neurons, glial cells such as astrocytes also express Reelin protein. While functional loss of astrocytes has been reported to be associated with AD, dysfunction of astrocytic Reelin signaling pathway has not received much attention. Therefore, we investigated the effects of α-boswellic acid (ABA) as one of the major component of Boswellia serrata resin on primary fetal human astrocytes under a stress paradigm as a possible model for AD through study on Reelin cascade. For this aim, we used streptozotocin (STZ), in which from an outlook generates Alzheimer's hallmarks in astrocytes, and assayed Reelin expression, Tau and Akt phosphorylation as well as reactive oxygen species (ROS) generation and apoptosis in the presences of ABA. Our results indicated that while STZ (100 µM) down-regulated the expression of Reelin, ABA (25 µM) up-regulated its expression (p < 0.01) for 24 h. ABA efficiently reduced hyperphosphorylated Tau (Ser404) in STZ-treated astrocytes (p < 0.01). Furthermore, STZ-induced apoptosis by increasing cleaved caspase three (p < 0.01) and ROS generation (p < 0.01), a further pathological hallmark of Tauopathy. On the other hand, ABA decreased ROS generation and promoted proliferation of astrocytes through elevating Survivin expression (p < 0.01). These results showed that ABA could be considered as a potent therapeutic agent for prevention and decreasing the progression of Alzheimer's hallmarks in astrocytes; however, more in vivo studies would be needed.

Prognostic Impact of Activated Leucocyte Cell Adhesion Molecule (ALCAM/CD166) in Infantile Neuroblastoma.

BACKGROUND/AIM: Activated leukocyte cell adhesion molecule (ALCAM/CD166) as a member of the 'immunoglobulin superfamily' is known to be involved in cancer cell proliferation and migration. The aim of this study was to investigate the expression of ALCAM in neuroblastoma tissues. MATERIALS AND METHODS: ALCAM expression was analyzed in primary neuroblastoma specimens by immunohistochemistry on microarray sections. Histopathological and clinical data were correlated with ALCAM expression and survival analysis was performed. RESULTS: Sixty-six children were included in the study. Strong expression of ALCAM was detected in 52 (79%) of the samples. Weak expression was significantly correlated with the International Neuroblastoma Staging System (INSS) stage (p=0.024) and positive n-MYC amplification (p=0.019). Recurrence-free survival (RFS) and overall survival (OS) were significantly shorter if ALCAM was expressed weakly (p=0.032 and p=0.001). CONCLUSION: Weak ALCAM expression was significantly correlated with established markers for poor prognosis, as well as shorter RFS and OS. ALCAM might be considered as a prognostic marker for infantile neuroblastoma.

Dragon (RGMb) induces oxaliplatin resistance in colon cancer cells.

Colorectal cancer (CRC) is one of the most commonly diagnosed cancers and a major cause of cancer mortality. Chemotherapy resistance remains a major challenge for treating advanced CRC. Therefore, the identification of targets that induce drug resistance is a priority for the development of novel agents to overcome resistance. Dragon (also known as RGMb) is a member of the repulsive guidance molecule (RGM) family. We previously showed that Dragon expression increases with CRC progression in human patients. In the present study, we found that Dragon inhibited apoptosis and increased viability of CMT93 and HCT116 cells in the presence of oxaliplatin. Dragon induced resistance of xenograft tumor to oxaliplatinin treatment in mice. Mechanistically, Dragon inhibited oxaliplatin-induced JNK and p38 MAPK activation, and caspase-3 and PARP cleavages. Our results indicate that Dragon may be a novel target that induces drug resistance in CRC.

Regulation of SATB1 during thymocyte development by TCR signaling.

T lymphocyte development and differentiation is a multi-step process that begins in the thymus and completed in the periphery. Sequential development of thymocytes is dependent on T cell receptor (TCR) signaling and an array of transcription factors. In this study we show that special AT-rich binding protein 1 (SATB1), a T lineage-enriched chromatin organizer and regulator, is induced in response to TCR signaling during early thymocyte development. SATB1 expression profile coincides with T lineage commitment and upregulation of SATB1 correlates with positive selection of thymocytes. CD4 thymocytes exhibit a characteristic bimodal expression pattern that corresponds to immature and mature CD4 thymocytes. We also demonstrate that GATA3, the key transcriptional regulator of αß T cells positively regulates SATB1 expression in thymocytes suggesting an important role for SATB1 during T cell development.