The neurobiological functions of a number of kinases expressed in the brain are unknown. Here, we report new findings on DCLK3 (Doublecortin-like kinase 3) which is preferentially expressed in neurons in the striatum and dentate gyrus. Its function has never been investigated. DCLK3 expression is markedly reduced in Huntington''s disease. Recent data obtained in studies related to cancer suggest DCLK3 could have anti-apoptotic effect. Thus, we hypothesized that early loss of DCLK3 in Huntington''s disease may render striatal neurons more susceptible to mutant huntingtin (mHtt). We discovered that DCLK3 silencing in the striatum of mice exacerbated the toxicity of an N-terminal fragment of mHtt. Conversely, overexpression of DCLK3 reduced neurodegeneration produced by mHtt. DCLK3 also produced beneficial effects on motor symptoms in a knock-in mouse model of Huntington''s disease. Using different mutants of DCLK3, we found that the kinase activity of the protein plays a key role in neuroprotection. To investigate the potential mechanisms underlying DCLK3 effects, we studied the transcriptional changes produced by the kinase domain in human striatal neurons in culture. Results show that DCLK3 regulates in a kinase-dependent manner the expression of many genes involved in transcription regulation and nucleosome/chromatin remodeling. Consistent with this, histological evaluation showed DCLK3 is present in the nucleus of striatal neurons and, protein-protein interaction experiments suggested that the kinase domain interacts with zinc finger proteins, including TADA3, a core component of SAGA complex. Our novel findings suggest that the presence of DCLK3 in striatal neurons may play a key role in transcription regulation and chromatin remodeling in these brain cells, and show that reduced expression of the kinase in Huntington's disease could render the striatum highly vulnerable to neurodegeneration. Examination of DCLK3 as neuroprotector against mutant huntingtin in vivo and in vitro models. Overall design: Examination of DCLK3 as neuroprotector against mutant huntingtin in vitro experiments.
The striatal kinase DCLK3 produces neuroprotection against mutant huntingtin.
Specimen part, Cell line, Subject
View SamplesCells were isolated from healthy human donors (n=2). Unstimulated cells. Cells were stained with CD4, CD45RA, CCR7 and CXCR7. Using flow cytometry, 4 CD4+ T cell populations were sorted: (1) Nave (CD45RA+CCR7+CXCR5-), (2) Central memory (CD45RA-CCR7+CXCR5-), (3) Effector memory (CD45RA-CCR7-CXCR5-) and (4) CXCR5+ cells (CD45RA-CCR7-CXCR5+)
CXCR5 expressing human central memory CD4 T cells and their relevance for humoral immune responses.
Specimen part
View SamplesPilocytic astrocytoma is the most common type of brain tumor in pediatric population, generally connected with favorable prognosis, although recurrences or dissemination sometimes are also observed. For tumors originating in supra- or infratentorial location different molecular background was suggested but plausible correlations between transcriptional profile and radiological features and/or clinical course are still undefined. The purpose of this study was to identify gene expression profiles related to the most frequent locations of this tumor, subtypes based on various radiological features and clinical pattern of the disease. According to the radiological features presented on MRI, all cases were divided into four subtypes: solid or mainly solid, cystic with an enhancing cyst wall, cystic with a non-enhancing cyst wall and solid with central necrosis. Bioinformatic analyses showed that gene expression profile of pilocytic astrocytoma highly depends on the tumor location. Most prominent differences were noted for IRX2, PAX3, CXCL14, LHX2, SIX6, CNTN1 and SIX1 genes expression which could distinguish pilocytic astrocytomas of different location even within supratentorial region. Analysis of the genes potentially associated between radiological features showed much weaker transcriptome differences. Single genes showed association with the tendency to progression. Here we showed that pilocytic astrocytomas of three different locations could be precisely differentiated on the basis of gene expression level but their transcriptional profiles did not strongly reflect the radiological appearance of the tumor or the course of the disease.
Transcriptional profiles of pilocytic astrocytoma are related to their three different locations, but not to radiological tumor features.
Sex, Age, Specimen part, Disease
View SamplesIn order to characterize the differences between second trimester Down syndrome (DS) and euploid fetuses, we compared gene expression in uncultured amniotic fluid supernatant samples. We identified individually differentially expressed genes via paired t-tests in the matched samples, and a set of differentially expressed genes on chromosome 21 using Gene Set Enrichment Analysis. Functional pathway analysis of the resulting genes highlighted the importance of oxidative stress, ion transport, and G-protein signaling in the DS fetuses.
Functional genomic analysis of amniotic fluid cell-free mRNA suggests that oxidative stress is significant in Down syndrome fetuses.
Sex, Specimen part
View SamplesWe have analyzed, using DNA microarrays, putative differences in gene-expression level between hereditary BRCA1 mutation-linked and sporadic breast cancer. Our results show that a previously reported marked difference between BRCA1-mutation linked and sporadic breast cancer was probably due to uneven stratification of samples with different ER status and basal-like versus luminal-like subtype. We observed that apparent difference between BRCA1-linked and other types of breast cancer found in univariate analysis was diminished when data were corrected for ER status and molecular subtype in multivariate analyses. In fact, the difference in gene expression pattern of BRCA1-mutated and sporadic cancer is very discrete. These conclusions were supported by the results of Q-PCR validation. We also found that BRCA1 gene inactivation due to promoter hypermethylation had similar effect on general gene expression profile as mutation-induced protein truncation. This suggests that in the molecular studies of hereditary breast cancer, BRCA1 gene methylation should be recognized and considered together with gene mutation.
BRCA1-related gene signature in breast cancer: the role of ER status and molecular type.
Age
View SamplesMolecular mechanisms of cell cycle exit are poorly understood. A group of genes required for cell cycle exit and maintenance of cell quiescence in human fibroblasts following serum deprivation has been recently identified. Studies on lymphocytes following growth factor deprivation-induced cell cycle exit have predominantly focused on the initiation of apoptosis. A set of genes involved in lymphocyte quiescence have also been identified among genes highly expressed in resting lymphocytes and down-regulated after cell activation. In our study, proliferating IL-2-dependent human T cells were forced to exit cell cycle by growth factor withdrawal, and their gene expression profiles were examined.
Molecular signature of cell cycle exit induced in human T lymphoblasts by IL-2 withdrawal.
No sample metadata fields
View SamplesThe discovery of fetal mRNA transcripts in maternal circulation holds great promise for noninvasive prenatal diagnosis. To identify potential fetal biomarkers, we studied whole blood and plasma transcripts common to term pregnant women and their newborns but reduced or absent in the postpartum mothers.
Gene expression analysis in pregnant women and their infants identifies unique fetal biomarkers that circulate in maternal blood.
Specimen part
View SamplesThe strength of T cell stimulation determines IL-7 responsiveness, recall potential and lineage commitment of primed human CD4+IL-7Rhi T cells
The strength of T cell stimulation determines IL-7 responsiveness, secondary expansion, and lineage commitment of primed human CD4+IL-7Rhi T cells.
No sample metadata fields
View SamplesThe introduction of microarray techniques to cancer research brought great expectations for finding biomarkers that would improve patients treatment; however, the results of such studies are poorly reproducible and critical analyses of these methods are rare. In this study, we examined global gene expression in 97 ovarian cancer samples. Also, validation of results by quantitative RT-PCR was performed on 30 additional ovarian cancer samples. We carried out a number of systematic analyses in relation to several defined clinicopathological features. The main goal of our study was to delineate the molecular background of ovarian cancer chemoresistance and find biomarkers suitable for prediction of patients prognosis. We found that histological tumor type was the major source of variability in genes expression, except for serous and undifferentiated tumors that showed nearly identical profiles. Analysis of clinical endpoints [tumor response to chemotherapy, overall survival, disease-free survival (DFS)] brought results that were not confirmed by validation either on the same group or on the independent group of patients. CLASP1 was the only gene that was found to be important for DFS in the independent group, whereas in the preceding experiments it showed associations with other clinical endpoints and with BRCA1 gene mutation; thus, it may be worthy of further testing. Our results confirm that histological tumor type may be a strong confounding factor and we conclude that gene expression studies of ovarian carcinomas should be performed on histologically homogeneous groups. Among the reasons of poor reproducibility of statistical results may be the fact that despite relatively large patients group, in some analyses one has to compare small and unequal classes of samples. In addition, arbitrarily performed division of samples into classes compared may not always reflect their true biological diversity. And finally, we think that clinical endpoints of the tumor probably depend on subtle changes in many and, possibly, alternative molecular pathways, and such changes may be difficult to demonstrate.
Gene expression analysis in ovarian cancer - faults and hints from DNA microarray study.
No sample metadata fields
View SamplesThis study provides a comparison of genes expressed in reconstructed cultured epidermis derived from four different donors.
Xenobiotic metabolism gene expression in the EpiDermin vitro 3D human epidermis model compared to human skin.
Sex, Specimen part
View Samples