Several studies have shown that negative and positive miRNA-mRNA correlations are symmetrically distributed. While negative correlations are consistent with a faster degradation of miRNA targets, the presence of positive correlations suggests bidirectional interactions between the two classes of molecules. However, a comprehensive study of miRNA and mRNA correlations is lacking. A homogeneous map of miRNA and mRNA relationships was obtained by multidimensional scaling (MDS) applied to a single matrix including both heterologous (miRNA-mRNA) and homologous (miRNA-miRNA and mRNA-mRNA) correlations.
Integrated ordination of miRNA and mRNA expression profiles.
Specimen partView Samples
White Striping and Wooden Breast (WS/WB) are abnormalities increasingly occurring in the fillets of high breast yield and growth rate chicken hybrids. These defects lead to consistent economic losses for poultry meat industry, as affected broilers fillets present an impaired visual appearance that negatively affects consumers acceptability. Previous studies have highlighted in affected fillets a deeply damaged muscle, showing profound inflammation, fibrosis and lipidosis. The present study investigated the differentially expressed genes and pathways linked to the compositional changes observed in WS/WB breast muscles, in order to outline a more complete framework of the gene networks related to the occurrence of this complex pathological picture. The biochemical composition was performed on 20 Pectoralis major samples obtained from high breast yield and growth rate broilers (10 affected vs. 10 normal) and 12 out of the 20 samples were used for the microarray gene expression profiling (6 affected vs. 6 normal). The obtained results indicate strong changes in muscle mineral composition, coupled to an increased deposition of fat. In addition, 204 differentially expressed genes (DEG) were found: 102 up-regulated and 102 down-regulated in affected breasts. The gene expression pathways found more altered in WS/WB muscles are those related to muscle development, polysaccharide metabolic processes, proteoglycans synthesis, inflammation and calcium signaling pathway. On the whole, the findings suggest that a multifactorial and complex etiology is associated with the occurrence of WS/WB muscle abnormalities, contributing to further define the transcription patterns associated to these myopathies.
Detection of differentially expressed genes in broiler pectoralis major muscle affected by White Striping - Wooden Breast myopathies.
Sex, Specimen partView Samples
Microarray analysis of Myd88-/-Trif-/- and Myd88-/-Rip2-/- macrophage responses to WT or dotA mutant L. pneumophila.
Type IV secretion-dependent activation of host MAP kinases induces an increased proinflammatory cytokine response to Legionella pneumophila.
No sample metadata fieldsView Samples
The liver has inherent regenerative capacity via mitotic division of mature hepatocytes. However, if the hepatic loss is massive or mature hepatocyte proliferation is impaired by chronic liver injury, HSPC are activated to support liver regeneration. Access to liver tissue from 4 patients who underwent liver transplantation for hepatitis B virus (HBV)- associated acute liver failure (ALF) provided us with the opportunity to investigate the molecular mechanisms of liver regeneration in humans by means of gene expression profiling and immunohistochemistry (IHC). Gene expression profiling of 17 liver specimens from the 4 ALF cases and individual liver specimens from 10 liver donors documented a distinct gene signature for ALF. However, unsupervised multidimensional scaling and hierarchical clustering identified two-well defined clusters that segregated according to the histopathological severity, i.e. massive hepatic necrosis (MHN; 2 patients) and submassive hepatic necrosis (SHN; 2 patients). We found that ALF is characterized by a strong hepatic stem/progenitor cell (HSPC) gene signature, as also confirmed by IHC, along with ductular reaction, both of which are more prominent in MHN. Interestingly, no evidence of further lineage differentiation was seen in MHN, whereas in SHN we detected cells with hepatocyte-like morphology. Strikingly, ALF was associated with a strong tumorigenesis gene signature. MHN had the greatest upregulation of cancer stem cell genes (EpCAM, CK19 and CK7), whereas the most upregulated genes in SHN were related to cellular growth and proliferation (AKR1B10, NQO1, RRM2, SFN, TOP2A, CCNB1, CDC20, ANLN and KI67). The extent of liver necrosis correlated with an overriding fibrogenesis gene signature, reflecting the wound healing process. Conclusion: Our data provide evidence of marked HSPC cell activation and fibrogenesis in HBV-associated ALF, which positively correlate with the extent of liver necrosis. Moreover, we detected a strong tumorigenesis gene signature in ALF, which underlines the relationship between liver regeneration and liver cancer.
Liver regeneration signature in hepatitis B virus (HBV)-associated acute liver failure identified by gene expression profiling.
Specimen part, Disease, Disease stage, SubjectView Samples
The second messenger cAMP acts via protein kinase A (PKA) to induce apoptosis by mechanisms that are poorly understood. Here, we assessed a role for mitochondria and analyzed gene expression in cAMP/PKA-promoted apoptosis by comparing wild-type (WT) S49 lymphoma cells and the S49 variant, D- (cAMP-deathless), which lacks cAMP-promoted apoptosis but has wild-type levels of PKA activity and cAMP-promoted G1 growth arrest. Treatment of WT, but not D-, S49 cells with 8-CPT-cAMP for 24 h induced loss of mitochondrial membrane potential, mitochondrial release of cytochrome c and Smac and increase in caspase-3 activity. Gene expression analysis (using Affymetrix 430 2.0 Arrays) revealed that WT and D- cells incubated with 8-CPT-cAMP have similar, but non-identical, extents of cAMP-regulated gene expression at 2h (~800 transcripts) and 6h (~1000 transcripts) (|Fold|>2, P<0.06); by contrast, at 24h ~2500 and ~1100 transcripts were changed in WT and D- cells, respectively. Using an approach that combined regression analysis, clustering and functional annotation to identify transcripts that showed differential expression between WT and D- cells, we found differences in cAMP-mediated regulation of mRNAs involved in transcriptional repression, apoptosis, the cell cycle, RNA splicing, Golgi and lysosomes. The 2 cell lines differed in CREB phosphorylation and expression of the transcriptional inhibitor Icer and in cAMP-regulated expression of genes in the Inhibitor of apoptosis (IAP) and Bcl families. The findings indicate that cAMP/PKA-promoted apoptosis of lymphoid cells occurs via mitochondrial-mediated events and imply that such apoptosis involves gene networks in multiple biochemical pathways.
Gene expression signatures of cAMP/protein kinase A (PKA)-promoted, mitochondrial-dependent apoptosis. Comparative analysis of wild-type and cAMP-deathless S49 lymphoma cells.
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Stem cells are a potential key strategy for treating neurodegenerative diseases in which the generation of new neurons is critical. A better understanding of the characteristics and molecular properties of neural stem cells (NSC) and differentiated neurons can help in assessing neuronal maturity and possibly in devising better therapeutic strategies. We have therefore performed an in-depth gene expression profiling study of the C17.2 NSC line and primary neurons (PN) derived from embryonic mouse brains. Microarray analysis revealed a neuron-specific gene expression signature that distinguishes PN from NSCs, with elevated levels of transcripts involved in neuronal functions such as neurite development, axon guidance, in PN. The same comparison revealed decreased levels of multiple cytokine transcripts such as IFN, TNF, TGF, and IL. Among the differentially expressed genes, we found a statistically significant enrichment of genes in the ephrin, neurotrophin, CDK5 and actin pathways which control multiple neuronal-specific functions. Furthermore, genes involved in cell cycle were among the most significantly changed in PN. In order to better understand the role of cell cycle arrest in mediating NSCs differentiation, we blocked the cell cycle of NSCs with Mitomycin C (MMC) and examined cellular morphology and gene expression signatures. Although these MMC-treated NSCs displayed a neuronal morphology and expressed some neuronal differentiation marker genes, their gene expression patterns was very different from primary neurons. We conclude that: 1) Fully differentiated primary neurons display a specific neuronal gene expression signature; 2) cell-cycle block in NSC does not induce the formation of fully differentiated neurons; 3) Cytokines such as IFN, TNF, TGF and IL are part of normal NSC function and/or physiology; 4) Signaling pathways of ephrin, neurotrophin, CDK5 and actin, related to major neuronal features, are dynamically enriched in genes showing changes in expression level.
Identification of a neuronal gene expression signature: role of cell cycle arrest in murine neuronal differentiation in vitro.
Sex, Specimen part, Cell lineView Samples
An efficient innate immune recognition of the intracellular parasite T. cruzi is crucial for host protection against development of Chagas disease, which often leads to multiple organ damage, particularly the heart leading to cardiomyopathy. Mechanisms modulated by MyD88 have been shown to be necessary for resistance against T, cruzi infection. Recently, Nod-like receptors have been shown to play an important role as innate immune sensors, particularly as they relate to inflammasome function, caspase activation, and inflammatory cytokine production. In this study, we aimed to investigate the participation of innate immune responses in general, and inflammasomes in particular, in heart inflammation and cardiac damage upon infection with the T. cruzi parasite.
Apoptosis-associated speck-like protein containing a caspase recruitment domain inflammasomes mediate IL-1β response and host resistance to Trypanosoma cruzi infection.
Specimen partView Samples
Hepatitis B virus (HBV)-associated acute liver failure (ALF) is a dramatic clinical syndrome due to a sudden loss of hepatic cells leading to multiorgan failure. The mechanisms whereby HBV induces ALF are unknown. We used gene expression profiling to establish a molecular definition of hepatitis B virus (HBV)-associated ALF. Two patients who underwent liver transplantation for HBV-associated ALF were studied. Gene expression profiling was performed on 8 liver specimens obtained from the two patients with ALF (4 samples per liver) and individual liver specimens from 8 liver donors and normal livers from 11 patients who underwent resection for angioma. Statistical analyses were used to identify the signature genes of HBV-associated ALF. Multivariate permutation analysis identified 1,368 transcripts that were differentially expressed in ALF; 709 were up-regulated and 659 down-regulated. The most represented up-regulated transcripts were those involved in the immune response, whereas the most abundant down-regulated transcripts were those involved in metabolism and hepatic synthesis. ALF was characterized by overriding B-cell signature comprising genes related to mature B cells and plasma cells with abundant polyclonal expression of immunoglobulin genes. By contrast, there was a limited T-cell signature and up-regulation of several inhibitors of T-cell activation. Immunohistochemical analysis confirmed the prominent B-cell signature showing diffuse liver infiltration by plasma blasts and plasma cells with strong cytoplasmic staining for IgM and IgG, associated with a significant deposition of complement factors. Using phage display technology, we demonstrated that the molecular target of the massive intrahepatic antibody response is the hepatitis B core antigen (HBcAg). These data suggest that the humoral immunity may exert a primary role in the pathogenesis of HBV-associated ALF.
B cell gene signature with massive intrahepatic production of antibodies to hepatitis B core antigen in hepatitis B virus-associated acute liver failure.
Specimen partView Samples