Molecular mechanisms underlying sarcopenia, the age-related loss of skeletal muscle mass and function, remain unclear. To identify molecular changes that correlated best with sarcopenia and might contribute to its pathogenesis, we determined global gene expression profiles in muscles of rats aged 6, 12, 18, 21, 24, and 27 months. These rats exhibit sarcopenia beginning at 21 months. Correlation of the gene expression versus muscle mass or age changes, and functional annotation analysis identified gene signatures of sarcopenia distinct from gene signatures of aging. Specifically, mitochondrial energy metabolism (e.g., tricarboxylic acid cycle and oxidative phosphorylation) pathway genes were the most downregulated and most significantly correlated with sarcopenia. Also, perturbed were genes/pathways associated with neuromuscular junction patency (providing molecular evidence of sarcopenia-related functional denervation and neuromuscular junction remodeling), protein degradation, and inflammation. Proteomic analysis of samples at 6, 18, and 27 months confirmed the depletion of mitochondrial energy metabolism proteins and neuromuscular junction proteins. Together, these findings suggest that therapeutic approaches that simultaneously stimulate mitochondrogenesis and reduce muscle proteolysis and inflammation have potential for treating sarcopenia.
Genomic and proteomic profiling reveals reduced mitochondrial function and disruption of the neuromuscular junction driving rat sarcopenia.
Sex, Age, Specimen part
View SamplesThis study seeks to understand the mechanisms behind enhanced lymphomagenesis observed in ImHABCL6/Uchl1 mice compared with ImHABCL6 alone. As the lymphomas arise from germinal center (GC) B-cells, we reasoned that transgenic Uchl1 altered the gene expression patterns in GC B-cells from these animals. We therefore isolated pre-malignant GC B-cells and examined the gene expression patterns to identify pathways affected by the addition of Uchl1.
UCH-L1 is induced in germinal center B cells and identifies patients with aggressive germinal center diffuse large B-cell lymphoma.
Specimen part
View SamplesRelatively brief bouts of exercise alter gene expression in peripheral blood mononuclear cells (PBMCs), but whether or not exercise changes gene expression in circulating neutrophils (whose numbers, like PBMCs, increase) is not known. We hypothesized that exercise would activate neutrophil genes involved in apoptosis, inflammation, and cell growth and repair, since these functions in leukocytes are known to be influenced by exercise. Blood was sampled before and immediately after 30-min of constant, heavy (about 80% peak O2 uptake) cycle-ergometer exercise in 12 healthy men (19-29 yr old) of average fitness. Neutrophils were isolated using density gradients; RNA was hybridized to Affymetrix U133+2 Genechip arrays. Using FDR<0.05 with 95% confidence a total of 526 genes were differentially expressed between before and after exercise. 316 genes had higher expression after exercise. The Jak/STAT pathway, known to inhibit apoptosis, was significantly activated (EASE score, p<0.005), but 14 genes were altered in a way likely to accelerate apoptosis as well. Similarly, both proinflammatory (e.g., IL32, TNFSF8 and CCR5) and anti-inflammatory (e.g., ANXA1) were affected. Growth and repair genes like AREG and FGF2 receptor genes (involved in angiogenesis) were also activated. Finally, a number of neutrophil genes known to be involved in pathological conditions like asthma and arthritis were altered by exercise, suggesting novel links between physical activity and disease or its prevention. In summary, brief heavy exercise leads to a previously unknown substantial and significant alteration in neutrophil gene expression.
Effects of 30 min of aerobic exercise on gene expression in human neutrophils.
No sample metadata fields
View SamplesExtracellular RNAs (exRNAs) in blood and other biofluids have attracted great interest as potential biomarkers in liquid biopsy applications, as well as for their potential biological functions. Whereas it is well-established that extracellular microRNAs are present in human blood circulation, the degree to which messenger RNAs (mRNA) and long noncoding RNAs (lncRNA) are represented in plasma is less clear. Here we report that mRNA and lncRNA species are present as small fragments in plasma that are not detected by standard small RNA-seq methods, because they lack 5'-phosphorylation or carry 3'-phosphorylation. We developed a modified sequencing protocol (termed "phospho-sRNA-seq") that incorporates upfront RNA treatment with T4 polynucleotide kinase (which also has 3' phosphatase activity) and compared it to a standard small RNA-seq protocol, using as input both a pool of synthetic RNAs with diverse 5' and 3' end chemistries, as well exRNA isolated from human blood plasma. Using a custom, high-stringency pipeline for data analysis we identified mRNA and lncRNA transcriptome fingerprints in plasma, including multiple tissue-specific gene sets. In a longitudinal study of hematopoietic stem cell transplant (HSCT) patients, we found different sets corresponding to bone marrow- and liver- enriched genes, which tracked with bone marrow recovery or liver injury, providing proof-of-concept validation of this method as a biomarker approach. By accessing a previously unexplored realm of mRNA and lncRNA fragments in blood plasma, phospho-sRNA-seq opens up a new space for plasma transcriptome-based biomarker development in diverse clinical settings. Overall design: ExRNA-seq libraries were prepared from platelet-poor plasma obtained from serial blood draws collected from two individuals undergoing bone marrow transplantation. A total of 11 samples were collected from each individual, starting prior to chemotherapy/ratiation treatment (approximately 7 days pre-HSCT) the day of transplant, and then weekly up to approximately Day 63.
Phospho-RNA-seq: a modified small RNA-seq method that reveals circulating mRNA and lncRNA fragments as potential biomarkers in human plasma.
No sample metadata fields
View SamplesTo investigate differential gene expression, we analyzed the entire transcriptomes of tumor and matched normal brain tissues obtained from a patient who had glioblastoma multiforme. We extracted and sequenced the mRNA using Illumina GA2 platform. The raw data was analyzed using our recently developed program called RNASEQR, as well as ERANGE, MapSplice, SpliceMap, and TopHat. Overall design: Tumor and matched control brain tissues were obtained from a Han-Chinese patient.
RNASEQR--a streamlined and accurate RNA-seq sequence analysis program.
Specimen part, Subject
View SamplesMutations in GRIN2B are associated with intellectual disability in humans. We generated iPSC derived mature cortical neurons with mutations in GRIN2B and compared them to isogenic control cells. We found that both loss of function (LOF) and reduced dosage (RD) mutations in GRIN2B lead to reduced expression of NMDAR genes and increased expression of marker of immaturity, including KI67 and MET. Overall design: Examination of transcriptome in iPSC-derved mature neurons with and without the presence of mutations in GRIN2B
Disruption of GRIN2B Impairs Differentiation in Human Neurons.
Subject
View SamplesMost human tumors have abnormal numbers of chromosomes, a condition known as aneuploidy. The mitotic checkpoint is an important mechanism that prevents aneuploidy through restraining the activity of the anaphase-promoting complex (APC). USP44 was identified as a key regulator of APC activation that maintains the association of MAD2 with the APC co-activator Cdc20. However, the physiological importance of USP44 and its impact on cancer biology are unknown. Here, we show that USP44 is required to prevent tumors in mice and is frequently down-regulated in human lung cancer. USP44 inhibits chromosome segregation errors independently of its role in the mitotic checkpoint by regulating proper centrosome separation, positioning, and mitotic spindle geometry, functions that require direct binding to the centriole protein, centrin. These data reveal a new role for the ubiquitin system in mitotic spindle regulation and underscore the importance of USP44 in the pathogenesis of human cancer.
USP44 regulates centrosome positioning to prevent aneuploidy and suppress tumorigenesis.
Sex, Disease, Disease stage
View SamplesThe type III RNase Dicer is responsible for the maturation and function of microRNA (miRNA) molecules in the cell. It is now well documented that Dicer and the fine-tuning of the miRNA gene network are important for neuronal integrity. However, the underlying mechanisms involved in neuronal death, particularly in the adult brain, remain poorly defined. Here, we show that absence of Dicer in the adult forebrain is accompanied by a mixed neurodegenerative phenotype. While neuronal loss is observed in the hippocampus, cellular shrinkage is predominant in the cortex. Interestingly, neuronal degeneration coincides with the hyperphosphorylation of endogenous tau at several epitopes previously associated with neurofibrillary pathology. Transcriptome analysis of enzymes involved in tau phosphorylation identified ERK1 as one of the candidate kinases responsible for this event in vivo. We further demonstrate that miRNAs belonging to the miR-15 family are potent regulators of ERK1 expression in mouse neuronal cells and co-expressed with ERK1/2 in vivo. Last, we show that miR-15a is specifically downregulated in Alzheimers disease brain. In sum, these results support the hypothesis that changes in the miRNA network may contribute to a neurodegenerative phenotype by affecting tau phosphorylation.
Genetic ablation of Dicer in adult forebrain neurons results in abnormal tau hyperphosphorylation and neurodegeneration.
Specimen part
View SamplesTo identify novel LXR target genes, we conducted transcriptional profiling studies using RAW264.7 cells ectopically expressing
Apoptotic cells promote their own clearance and immune tolerance through activation of the nuclear receptor LXR.
Cell line
View Sampleswt1a:GFP labels a population of subepicardial cells in the uninjured ventricle. Here we compare the expression profile of wt1a:GFP-positive cells to the rest of the cells of the ventricle. Overall design: Four paired biological replicates of wt1a:GFP-positive and wt1a:GFP-negative cells obtained from pools of 3-5 zebrafish heart ventricles.
Transient fibrosis resolves via fibroblast inactivation in the regenerating zebrafish heart.
No sample metadata fields
View Samples