Gene Programs (gene + program)

Distribution by Scientific Domains


Selected Abstracts


Metabolic gene switching in the murine female heart parallels enhanced mitochondrial respiratory function in response to oxidative stress

FEBS JOURNAL, Issue 20 2007
M. Faadiel Essop
The mechanisms underlying increased cardioprotection in younger female mice are unclear. We hypothesized that serine-threonine protein kinase (protein kinase B; Akt) triggers a metabolic gene switch (decreased fatty acids, increased glucose) in female hearts to enhance mitochondrial bioenergetic capacity, conferring protection against oxidative stress. Here, we employed male and female control (db/+) and obese (db/db) mice. We found diminished transcript levels of peroxisome proliferator-activated receptor-alpha, muscle-type carnitine palmitoyltransferase 1 and pyruvate dehydrogenase kinase 4 in female control hearts versus male hearts. Moreover, females displayed improved recovery of cardiac mitochondrial respiratory function and higher ATP levels versus males in response to acute oxygen deprivation. All these changes were reversed in female db/db hearts. However, we found no significant gender-based differences in levels of Akt, suggesting that Akt-independent signaling mechanisms are responsible for the resilient mitochondrial phenotype observed in female mouse hearts. As glucose is a more energetically efficient fuel substrate when oxygen is limiting, this gene program may be a crucial component that enhances tolerance to oxygen deprivation in female hearts. [source]


Signaling networks guiding epithelial,mesenchymal transitions during embryogenesis and cancer progression

CANCER SCIENCE, Issue 10 2007
Aristidis Moustakas
Epithelial,mesenchymal transition (EMT) describes the differentiation switch between polarized epithelial cells and contractile and motile mesenchymal cells, and facilitates cell movements and generation of new tissue types during embryogenesis. Many secreted polypeptides are implicated in the EMT process and their corresponding intracellular transduction pathways form highly interconnected networks. Transforming growth factor-,, Wnt, Notch and growth factors acting through tyrosine kinase receptors induce EMT and often act in a sequential manner. Such growth factors orchestrate the concerted regulation of an elaborate gene program and a complex protein network, needed for establishment of new mesenchymal phenotypes after disassembly of the main elements of epithelial architecture, such as desmosomes, as well as tight, adherens and gap junctions. EMT of tumor cells occurs during cancer progression and possibly generates cell types of the tumor stroma, such as cancer-associated myofibroblasts. EMT contributes to new tumor cell properties required for invasiveness and vascular intravasation during metastasis. Here we present some of the current mechanisms that mediate the process of EMT and discuss their relevance to cancer progression. (Cancer Sci 2007; 98: 1512,1520) [source]


Integrative genomic analyses of neurofibromatosis tumours identify SOX9 as a biomarker and survival gene

EMBO MOLECULAR MEDICINE, Issue 4 2009
Shyra J. Miller
Abstract Understanding the biological pathways critical for common neurofibromatosis type 1 (NF1) peripheral nerve tumours is essential, as there is a lack of tumour biomarkers, prognostic factors and therapeutics. We used gene expression profiling to define transcriptional changes between primary normal Schwann cells (n,=,10), NF1-derived primary benign neurofibroma Schwann cells (NFSCs) (n,=,22), malignant peripheral nerve sheath tumour (MPNST) cell lines (n,=,13), benign neurofibromas (NF) (n,=,26) and MPNST (n,=,6). Dermal and plexiform NFs were indistinguishable. A prominent theme in the analysis was aberrant differentiation. NFs repressed gene programs normally active in Schwann cell precursors and immature Schwann cells. MPNST signatures strongly differed; genes up-regulated in sarcomas were significantly enriched for genes activated in neural crest cells. We validated the differential expression of 82 genes including the neural crest transcription factor SOX9 and SOX9 predicted targets. SOX9 immunoreactivity was robust in NF and MPSNT tissue sections and targeting SOX9 , strongly expressed in NF1-related tumours , caused MPNST cell death. SOX9 is a biomarker of NF and MPNST, and possibly a therapeutic target in NF1. [source]


Plasticity of human skeletal muscle: gene expression to in vivo function

EXPERIMENTAL PHYSIOLOGY, Issue 5 2007
Stephen D. R. Harridge
Human skeletal muscle is a highly heterogeneous tissue, able to adapt to the different challenges that may be placed upon it. When overloaded, a muscle adapts by increasing its size and strength through satellite-cell-mediated mechanisms, whereby protein synthesis is increased and new nuclei are added to maintain the myonuclear domain. This process is regulated by an array of mechanical, hormonal and nutritional signals. Growth factors, such as insulin-like growth factor I (IGF-I) and testosterone, are potent anabolic agents, whilst myostatin acts as a negative regulator of muscle mass. Insulin-like growth factor I is unique in being able to stimulate both the proliferation and the differentiation of satellite cells and works as part of an important local repair and adaptive mechanism. Speed of movement, as characterized by maximal velocity of shortening (Vmax), is regulated primarily by the isoform of myosin heavy chain (MHC) contained within a muscle fibre. Human fibres can express three MHCs: MHC-I, -IIa and -IIx, in order of increasing Vmax and maximal power output. Training studies suggest that there is a subtle interplay between the MHC-IIa and -IIx isoforms, with the latter being downregulated by activity and upregulated by inactivity. However, switching between the two main isoforms appears to require significant challenges to a muscle. Upregulation of fast gene programs is caused by prolonged disuse, whilst upregulation of slow gene programs appears to require significant and prolonged activity. The potential mechanisms by which alterations in muscle composition are mediated are discussed. The implications in terms of contractile function of altering muscle phenotype are discussed from the single fibre to the whole muscle level. [source]


Antibody-based proteomics for esophageal cancer: Identification of proteins in the nuclear factor-,B pathway and mitotic checkpoint

CANCER SCIENCE, Issue 9 2009
Norihisa Uemura
To identify the molecular background of esophageal cancer, we conducted a proteomics study using an antibody microarray consisting of 725 antibodies and surgical specimens from three cases. The microarray analysis identified 24 proteins with aberrant expression in esophageal cancer compared with the corresponding normal mucosa. The overexpression of 14 of the 24 proteins was validated by western blotting analysis of the same samples. These 14 proteins were examined by immunohistochemistry, in which nine proteins showed consistent results with those obtained by western blotting. Among the nine proteins, seven were localized in tumor cells, and two in infiltrating cells. The former included proteins associated with mitotic checkpoint control and the nuclear factor (NF)-,B pathway. Although mitotic checkpoint gene products (budding uninhibited by benzidazoles 1 homolog beta (BubR1) and mitotic arrest deficient-like 1 (Mad2)) have previously been reported to be involved in esophageal cancer, the association of NF-,B-activating kinase, caspase 10, and activator protein-1 with esophageal cancer has not been previously reported. These proteins play a key role in the NF-,B pathway, and NF-,B is a signal transduction factor that has emerged as an important modulator of altered gene programs and malignant phenotype in the development of cancer. The association of these proteins with esophageal cancer may indicate that mitotic checkpoint gene products and NF-,B play an important part in the carcinogenesis of esophageal cancer. (Cancer Sci 2009; 100: 1612,1622) [source]