REDD1 induction regulates the skeletal muscle gene expression signature following acute aerobic exercise.

The metabolic stress placed on skeletal muscle by aerobic exercise promotes acute and long-term health benefits in part through changes in gene expression. However, the transducers that mediate altered gene expression signatures have not been completely elucidated. Regulated in development and DNA damage 1 (REDD1) is a stress-induced protein whose expression is transiently increased in skeletal muscle following acute aerobic exercise. However, the role of this induction remains unclear. Because REDD1 altered gene expression in other model systems, we sought to determine whether REDD1 induction following acute exercise altered the gene expression signature in muscle. To do this, wild-type and REDD1-null mice were randomized to remain sedentary or undergo a bout of acute treadmill exercise. Exercised mice recovered for 1, 3, or 6 h before euthanization. Acute exercise induced a transient increase in REDD1 protein expression within the plantaris only at 1 h postexercise, and the induction occurred in both cytosolic and nuclear fractions. At this time point, global changes in gene expression were surveyed using microarray. REDD1 induction was required for the exercise-induced change in expression of 24 genes. Validation by RT-PCR confirmed that the exercise-mediated changes in genes related to exercise capacity, muscle protein metabolism, neuromuscular junction remodeling, and Metformin action were negated in REDD1-null mice. Finally, the exercise-mediated induction of REDD1 was partially dependent upon glucocorticoid receptor activation. In all, these data show that REDD1 induction regulates the exercise-mediated change in a distinct set of genes within skeletal muscle.

Curcumin prevents corticosterone-induced neurotoxicity and abnormalities of neuroplasticity via 5-HT receptor pathway.

Curcumin, a major active component of Curcuma longa, possesses antioxidant and neuroprotective activities. The present study explores the mechanisms underlying the neuroprotective effect of curcumin against corticosterone and its relation to 5-hydroxy tryptamine (5-HT) receptors. Exposure of cortical neurons to corticosterone results in decreased mRNA levels for three 5-HT receptor subtypes, 5-HT(1A), 5-HT(2A) and 5-HT(4), but 5-HT(1B,) 5-HT(2B), 5-HT(2C), 5-HT(6) and 5-HT(7) receptors remain unchanged. Pre-treatment with curcumin reversed this effect on mRNA for the 5-HT(1A) and 5-HT(4) receptors, but not for the 5-HT(2A) receptor. Moreover, curcumin exerted a neuroprotective effect against corticosterone-induced neuronal death. This observed effect of curcumin was partially blocked by either 5-HT(1A) receptor antagonist p-MPPI or 5-HT(4) receptor antagonist RS 39604 alone; whereas, the simultaneous application of both antagonists completely reversed the effect. Curcumin was also found to regulate corticosterone-induced morphological changes such as increases in soma size, dendritic branching and dendritic spine density, as well as elevate synaptophysin expression in cortical neurons. p-MPPI and RS 39604 reversed the effect of curcumin-induced change in neuronal morphology and synaptophysin expression of corticosterone-treated neurons. In addition, an increase in cyclic adenosine monophosphate (cAMP) level was observed after curcumin treatment, which was further prevented by RS 39604, but not by p-MPPI. However, curcumin-induced elevation in protein kinase A activity and phosphorylation of cAMP response element-binding protein levels were inhibited by both p-MPPI and RS 39604. These findings suggest that the neuroprotection and modulation of neuroplasticity exhibited by curcumin might be mediated, at least in part, via the 5-HT receptor-cAMP-PKA-CREB signal pathway.

Deep Sequencing-Identified Kanamycin-Resistant Paenibacillus sp. Strain KS1 Isolated from Epiphyte Tillandsia usneoides (Spanish Moss) in Central Florida, USA.

Paenibacillus sp. strain KS1 was isolated from an epiphyte, Tillandsia usneoides (Spanish moss), in central Florida, USA. Here, we report a draft genome sequence of this strain, which consists of a total of 398 contigs spanning 6,508,195 bp, with a G+C content of 46.5% and comprising 5,401 predicted coding sequences.

Whole-Genome Sequence of Pantoea americana Strain VS1, an Extended-Spectrum ß-Lactamase-Producing Epibiont Isolated from Magnolia grandiflora.

Pantoea americana strain VS1, an extended-spectrum ß-lactamase-producing epibiont, was isolated from Magnolia grandiflora in central Florida, USA. Here, we report the de novo whole-genome sequence of this strain, which consists of a total of 191 contigs spanning 5,412,831 bp, with a GC content of 57.3% and comprising 4,836 predicted coding sequences.

De Novo Whole-Genome Sequence of Pantoea latae Strain AS1, Isolated from Zamia floridana Rhizosphere in Central Florida, USA.

Pantoea latae strain AS1 was isolated from the rhizophere of a cycad, Zamia floridana, in central Florida, USA. Here, we report the de novo whole-genome sequence of this strain, which consists of a total of 83 contigs spanning 4,960,415 bp, with a G+C content of 59.6%, and comprising 4,527 predicted coding sequences.

Whole-Genome Sequence of Bacillus stratosphericus Strain 5Co, Isolated from Lichen Usnea florida in Central Florida, United States, with High Tolerance to Salt and Heavy Metal.

Bacillus stratosphericus strain 5Co was isolated from lichen Usnea florida in central Florida, United States. Here, we report a draft genome sequence of this strain, which consists of 159 contigs spanning 3,628,496 bp, with a G+C content of 41.3% and comprises 3,729 predicted coding sequences.

Draft Genome Sequences of Extended-Spectrum-Beta-Lactamase-Producing Morganella morganii Strains AA1 and AV1, Isolated from a Freshwater Lake and Eicchorniacrassipes Roots.

Two strains of Morganella morganii, AA1 and AV1, were isolated from freshwater and Eicchornia crassipes roots, respectively. Here, we report their draft genome sequences, which are ~3.6 Mb and have 51% G+C content. The predicted coding sequences (3,259 for strain AA1 and 3,345 for strain AV1) encode beta-lactamases, transpeptidases, and penicillin-binding proteins.

The functional characterization of long noncoding RNA SPRY4-IT1 in human melanoma cells.

Expression of the long noncoding RNA (lncRNA) SPRY4-IT1 is low in normal human melanocytes but high in melanoma cells. siRNA knockdown of SPRY4-IT1 blocks melanoma cell invasion and proliferation, and increases apoptosis. To investigate its function further, we affinity purified SPRY4-IT1 from melanoma cells and used mass spectrometry to identify the protein lipin 2, an enzyme that converts phosphatidate to diacylglycerol (DAG), as a major binding partner. SPRY4-IT1 knockdown increases the accumulation of lipin2 protein and upregulate the expression of diacylglycerol O-acyltransferase 2 (DGAT2) an enzyme involved in the conversion of DAG to triacylglycerol (TAG). When SPRY4-IT1 knockdown and control melanoma cells were subjected to shotgun lipidomics, an MS-based assay that permits the quantification of changes in the cellular lipid profile, we found that SPRY4-IT1 knockdown induced significant changes in a number of lipid species, including increased acyl carnitine, fatty acyl chains, and triacylglycerol (TAG). Together, these results suggest the possibility that SPRY4-IT1 knockdown may induce apoptosis via lipin 2-mediated alterations in lipid metabolism leading to cellular lipotoxicity.

An SREBP-responsive microRNA operon contributes to a regulatory loop for intracellular lipid homeostasis.

Sterol regulatory element-binding proteins (SREBPs) have evolved as a focal point for linking lipid synthesis with other pathways that regulate cell growth and survival. Here, we have uncovered a polycistrionic microRNA (miRNA) locus that is activated directly by SREBP-2. Two of the encoded miRNAs, miR-182 and miR-96, negatively regulate the expression of Fbxw7 and Insig-2, respectively, and both are known to negatively affect nuclear SREBP accumulation. Direct manipulation of this miRNA pathway alters nuclear SREBP levels and endogenous lipid synthesis. Thus, we have uncovered a mechanism for the regulation of intracellular lipid metabolism mediated by the concerted action of a pair of miRNAs that are expressed from the same SREBP-2-regulated miRNA locus, and each targets a different protein of the multistep pathway that regulates SREBP function. These studies reveal an miRNA "operon" analogous to the classic model for genetic control in bacterial regulatory systems.

Genome-wide methylated CpG island profiles of melanoma cells reveal a melanoma coregulation network.

Metastatic melanoma is a malignant cancer with generally poor prognosis, with no targeted chemotherapy. To identify epigenetic changes related to melanoma, we have determined genome-wide methylated CpG island distributions by next-generation sequencing. Melanoma chromosomes tend to be differentially methylated over short CpG island tracts. CpG islands in the upstream regulatory regions of many coding and noncoding RNA genes, including, for example, TERC, which encodes the telomerase RNA, exhibit extensive hypermethylation, whereas several repeated elements, such as LINE 2, and several LTR elements, are hypomethylated in advanced stage melanoma cell lines. By using CpG island demethylation profiles, and by integrating these data with RNA-seq data obtained from melanoma cells, we have identified a co-expression network of differentially methylated genes with significance for cancer related functions. Focused assays of melanoma patient tissue samples for CpG island methylation near the noncoding RNA gene SNORD-10 demonstrated high specificity.

Epigenetic regulation of microRNA-375 and its role in melanoma development in humans.

To identify epigenetically regulated miRNAs in melanoma, we treated a stage 3 melanoma cell line WM1552C, with 5AzadC and/or 4-PBA. Several hypermethylated miRNAs were detected, one of which, miR-375, was highly methylated and was studied further. Minimal CpG island methylation was observed in melanocytes, keratinocytes, normal skin, and nevus but hypermethylation was observed in patient tissue samples from primary, regional, distant, and nodular metastatic melanoma. Ectopic expression of miR-375 inhibited melanoma cell proliferation, invasion, and cell motility, and induced cell shape changes, strongly suggesting that miR-375 may have an important function in the development and progression of human melanomas.

Epigenetic regulation of microRNA genes and the role of miR-34b in cell invasion and motility in human melanoma.

Invasive melanoma is the most lethal form of skin cancer. The treatment of melanoma-derived cell lines with 5-aza-2'-deoxycytidine (5-Aza-dC) markedly increases the expression of several miRNAs, suggesting that the miRNA-encoding genes might be epigenetically regulated, either directly or indirectly, by DNA methylation. We have identified a group of epigenetically regulated miRNA genes in melanoma cells, and have confirmed that the upstream CpG island sequences of several such miRNA genes are hypermethylated in cell lines derived from different stages of melanoma, but not in melanocytes and keratinocytes. We used direct DNA bisulfite and immunoprecipitated DNA (Methyl-DIP) to identify changes in CpG island methylation in distinct melanoma patient samples classified as primary in situ, regional metastatic, and distant metastatic. Two melanoma cell lines (WM1552C and A375 derived from stage 3 and stage 4 human melanoma, respectively) were engineered to ectopically express one of the epigenetically modified miRNA: miR-34b. Expression of miR-34b reduced cell invasion and motility rates of both WM1552C and A375, suggesting that the enhanced cell invasiveness and motility observed in metastatic melanoma cells may be related to their reduced expression of miR-34b. Total RNA isolated from control or miR-34b-expressing WM1552C cells was subjected to deep sequencing to identify gene networks around miR-34b. We identified network modules that are potentially regulated by miR-34b, and which suggest a mechanism for the role of miR-34b in regulating normal cell motility and cytokinesis.