ABSTRACT:Pregnancy requires a higher functional beta cell mass and this is associated with profound changes in the gene expression profile of pancreatic islets. Taking Tph1 as a sensitive marker for pregnancy-related islet mRNA expression in female mice, we previously identified prolactin receptors and placental lactogen as key signalling molecules. Since beta cells from male mice also express prolactin receptors, the question arose whether male and female islets have the same phenotypic resilience at the mRNA level during pregnancy. We addressed this question in vitro, by using islet tissue culture with placental lactogen and in vivo, by transplanting male or female islets into female acceptor mice. Additionally, the islet mRNA expression of pregnant prolactin receptor deficient mice was compared with that of their pregnant wild-type littermates. When cultured with placental lactogen, or transplanted in female recipients that became pregnant (day 12.5), male islets induced the islet pregnancy gene signature, which we defined as the 12 highest induced genes in non-transplanted female islets at day 12.5 of pregnancy. In addition, serotonin immunoreactivity was also induced in these male transplanted islets at day 12.5 of pregnancy. In order to investigate the importance of prolactin receptors in these mRNA changes we used a prolactin receptor deficient mouse model. For the 12 genes of the signature, which are highly induced in control pregnant mice, no significant induction of mRNA transcripts was found at day 9.5 of pregnancy. Together, our results support the key role of placental lactogen as a circulating factor that can trigger the pregnancy mRNA profile in male and female beta cells.
Prolactin receptors and placental lactogen drive male mouse pancreatic islets to pregnancy-related mRNA changes.
Sex, Specimen part
View SamplesABSTRACT:Pregnancy requires a higher functional beta cell mass and this is associated with profound changes in the gene expression profile of pancreatic islets. Taking Tph1 as a sensitive marker for pregnancy-related islet mRNA expression in female mice, we previously identified prolactin receptors and placental lactogen as key signalling molecules. Since beta cells from male mice also express prolactin receptors, the question arose whether male and female islets have the same phenotypic resilience at the mRNA level during pregnancy. We addressed this question in vitro, by using islet tissue culture with placental lactogen and in vivo, by transplanting male or female islets into female acceptor mice. Additionally, the islet mRNA expression of pregnant prolactin receptor deficient mice was compared with that of their pregnant wild-type littermates. When cultured with placental lactogen, or transplanted in female recipients that became pregnant (day 12.5), male islets induced the islet pregnancy gene signature, which we defined as the 12 highest induced genes in non-transplanted female islets at day 12.5 of pregnancy. In addition, serotonin immunoreactivity was also induced in these male transplanted islets at day 12.5 of pregnancy. In order to investigate the importance of prolactin receptors in these mRNA changes we used a prolactin receptor deficient mouse model. For the 12 genes of the signature, which are highly induced in control pregnant mice, no significant induction of mRNA transcripts was found at day 9.5 of pregnancy. Together, our results support the key role of placental lactogen as a circulating factor that can trigger the pregnancy mRNA profile in male and female beta cells.
Prolactin receptors and placental lactogen drive male mouse pancreatic islets to pregnancy-related mRNA changes.
Specimen part
View SamplesDrought tolerance is a key trait for increasing and stabilizing barley productivity in dry areas worldwide. Identification of the genes responsible for drought tolerance in barley (Hordeum vulgare L.) will facilitate understanding of the molecular mechanisms of drought tolerance, and also genetic improvement of barley through marker-assisted selection or gene transformation. To monitor the changes in gene expression at transcription levels in barley leaves during the reproductive stage under drought conditions, the 22K Affymetrix Barley 1 microarray was used to screen two drought-tolerant barley genotypes, Martin and Hordeum spontaneum 41-1 (HS41-1), and one drought-sensitive genotype Moroc9-75. Seventeen genes were expressed exclusively in the two drought-tolerant genotypes under drought stress, and their encoded proteins may play significant roles in enhancing drought tolerance through controlling stomatal closure via carbon metabolism (NADP malic enzyme (NADP-ME) and pyruvate dehydrogenase (PDH), synthesizing the osmoprotectant glycine-betaine (C-4 sterol methyl oxidase (CSMO), generating protectants against reactive-oxygen-species scavenging (aldehyde dehydrogenase (ALDH), ascorbate-dependant oxidoreductase (ADOR), and stabilizing membranes and proteins (heat-shock protein 17.8 (HSP17.8) and dehydrin 3 (DHN3). Moreover, 17 genes were abundantly expressed in Martin and HS41-1 compared with Moroc9-75 under both drought and control conditions. These genes were likely constitutively expressed in drought-tolerant genotypes. Among them, 7 known annotated genes might enhance drought tolerance through signaling (such as calcium-dependent protein kinase (CDPK) and membrane steroid binding protein (MSBP), anti-senescence (G2 pea dark accumulated protein GDA2) and detoxification (glutathione S-transferase (GST) pathways. In addition, 18 genes, including those encoding l-pyrroline-5-carboxylate synthetase (P5CS), protein phosphatase 2C-like protein (PP2C) and several chaperones, were differentially expressed in all genotypes under drought; thus, they were more likely general drought-responsive genes in barley. These results could provide new insights into further understanding of drought-tolerance mechanisms in barley.
Differentially expressed genes between drought-tolerant and drought-sensitive barley genotypes in response to drought stress during the reproductive stage.
Specimen part, Treatment
View SamplesSeveral reports have focused on the identification of biological elements involved in the development of abnormal systemic biochemical alterations in chronic kidney disease, but this abundant literature results most of the time fragmented. To better define the cellular machinery associated to this condition, we employed an innovative high-throughput approach based on a whole transcriptomic analysis and classical biomolecular methodologies. The genomic screening of peripheral blood mononuclear cells revealed that 44 genes were up-regulated in both chronic kidney disease patients in conservative treatment (CKD, n=9) and hemodialysis (HD, n=17) compared to healthy subjects (NORM) (p<0.001, FDR=1%). Functional analysis demonstrated that 11/44 genes were involved in the oxidative phosphorylation system (OXPHOS). Western blotting for COXI and COXIV, key constituents of the complex IV of OXPHOS, performed on an independent testing-group (12 NORM, 10 CKD and 14 HD) confirmed the elevated synthesis of these subunits in CKD/HD patients. However, complex IV activity was significantly reduced in CKD/HD patients compared to NORM (p<0.01). Finally, CKD/HD patients presented higher reactive oxygen species and 8-hydroxydeoxyguanosine levels compared to NORM. Taken together these results suggest, for the first time, that CKD/HD patients may have an impaired mitochondrial respiratory system and this condition may be both the consequence and the cause of an enhanced oxidative stress.
Mitochondrial dysregulation and oxidative stress in patients with chronic kidney disease.
Disease, Treatment, Subject
View SamplesThe functioning of a specific tissue depends on the expression pattern of the different genes. We used microarrays to compare gene expression across different murine tissues, to get a better understanding in the expression pattern and functioning of the different tissues. With this analysis, we were not only able to identify genes that were specifically expressed in a spicific tissue but, as important, we also identified genes that were specifically repressed in a tissue, compared to al the other analysed tissues.
Tissue-specific disallowance of housekeeping genes: the other face of cell differentiation.
Sex, Specimen part
View SamplesWe used Affymetrix Gene Arrays (1.0 ST) to compare gene expression across different murine tissues.
Tissue-specific disallowance of housekeeping genes: the other face of cell differentiation.
Specimen part
View SamplesABSTRACT: The human growth hormone (hGH) minigene is frequently used in the derivation of transgenic mouse lines to enhance transgene expression. Although this minigene is present in the transgenes as a secondcistron, and thus not thought to be expressed, we found that three commonly used lines, Pdx1-CreLate, RIP-Cre, and MIP-GFP, each expressed significant amounts of hGH in pancreatic islets. Locally secreted hGH binds to prolactin receptors on cells, activates STAT5 signaling, and induces pregnancy-like changes in gene expression, thereby augmenting pancreatic cell mass and insulin content. In addition, islets of Pdx1-CreLate mice have lower GLUT2 expression and reduced glucose-induced insulin release and are protected against the cell toxin streptozotocin. These findings may be important when interpreting results obtained when these and other hGH minigene-containing transgenic mice are used.
Impaired islet function in commonly used transgenic mouse lines due to human growth hormone minigene expression.
Specimen part
View SamplesWe used microarrays to compare gene expression across different murine tissues.
Mice deficient in the respiratory chain gene Cox6a2 are protected against high-fat diet-induced obesity and insulin resistance.
Sex, Specimen part
View SamplesAlternative promoters (APs) occur in >30% protein-coding genes and contribute to proteome diversity. However, large-scale analyses of AP regulation are lacking, and little is known about their potential physiopathologic significance. To better understand the transcriptomic impact of estrogens, which play a major role in breast cancer, we analyzed gene and AP regulation by estradiol in MCF7 cells using pan-genomic exon arrays. We thereby identified novel estrogen-regulated genes, and determined the regulation of AP-encoded transcripts in 150 regulated genes. In <30% cases, APs were regulated in a similar manner by estradiol, while in >70% cases, they were regulated differentially. The patterns of AP regulation correlated with the patterns of estrogen receptor (ER) and CCCTC-binding factor (CTCF) binding sites at regulated gene loci. Interestingly, among genes with differentially regulated APs, we identified cases where estradiol regulated APs in an opposite manner, sometimes without affecting global gene expression levels. This promoter switch was mediated by the DDX5/DDX17 family of ER coregulators. Finally, genes with differentially regulated promoters were preferentially involved in specific processes (e.g., cell structure and motility, and cell cycle). We show in particular that isoforms encoded by the NET1 gene APs, which are inversely regulated by estradiol, play distinct roles in cell adhesion and cell cycle regulation, and that their expression is differentially associated with prognosis in ER+ breast cancer. Altogether, this study identifies the patterns of AP regulation in estrogen-regulated genes, demonstrates the contribution of AP-encoded isoforms to the estradiol-regulated transcriptome, as well as their physiopathologic significance in breast cancer.
Estrogen regulation and physiopathologic significance of alternative promoters in breast cancer.
Disease, Disease stage, Cell line, Time
View SamplesThis study was designed to identify candidate genes associated with iron efficiency in soybeans. Two genotypes, Clark (PI548553) and IsoClark (PI547430), were grown in both iron sufficient (100uM Fe(NO3)3) and iron deficient (50uM Fe(NO3)3) hydroponics conditions. The second trifoliate was harvested for RNA extraction for the microarray experiment. Candidate genes were identified by comparing gene expression profiles within genotypes between the two iron growth conditions.
Integrating microarray analysis and the soybean genome to understand the soybeans iron deficiency response.
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