Project description:MicroRNAs (miRNAs) are important in the regulation of many biological processes including muscle development. However, little is known regarding miRNA regulation of muscle regeneration. In mature murine tibialis anterior muscle following injury, 298 miRNAs were significantly changed during the time course of muscle regeneration including 86 that were altered greater than 10-fold as compared to uninjured muscle. Temporal miRNA expression patterns were identified and included inflammation-related miRNAs (miR-223 and -147) that increased immediately after injury; this pattern contrasted to that of mature muscle-specific miRNAs (miR-1, -133a and -499) that were abruptly decreased following injury and then up-regulated in later regenerative events. Another cluster of miRNAs were transiently increased in the early days of muscle regeneration. This included miR-351, a miRNA that was also transiently expressed during myogenic progenitor cell (MPC) differentiation in vitro. Based on computational predictions, further studies demonstrated that E2f3 was a target of miR-351 in myoblasts. Moreover, knockdown of miR-351 expression inhibited MPC proliferation and promoted apoptosis during MPC differentiation, whereas miR-351 overexpression protected MPC from apoptosis during differentiation. Collectively, these observations suggest that miR-351 is involved in both the maintenance of MPC proliferation and the transition of MPC into differentiated myotubes. Thus, a novel, time-dependent sequence of molecular events during skeletal muscle regeneration has been identified, i.e., miR-351 inhibits E2f3 expression, a key regulator of cell cycle progression and proliferation, and promotes MPC proliferation and protects early differentiating MPC from apoptosis, important events in the hostile tissue environment after acute muscle injury. Skeletal muscles are damaged and repaired repeatedly throughout life. Muscle regeneration maintains locomotor function during aging and delays the appearance of clinical symptoms in neuromuscular diseases, such as Duchenne muscular dystrophy. The capacity for skeletal muscle growth and regeneration is conferred by satellite cells located between the basal lamina and the sarcolemma of mature myofibers. Upon injury, satellite cells reenter the cell cycle, proliferate, and then exit the cell cycle either to renew the quiescent satellite cell pool or to differentiate into mature myofibers. Despite recent advances, genes involved in these processes are still largely unknown. Understanding the molecular mechanisms that regulate satellite cell activities could promote development of novel countermeasures to enhance muscle regeneration that is compromised by diseases or aging. Using a muscle injury mouse model, we profiled miRNA expression during muscle regeneration.
Project description:To identify the gene signature induced by MCMV that modulates innate immune function Microarray comparison of gene expression in the lungs of 4 individual naive and 4 eMCMV infected mice two weeks after infection.
Project description:We show that traumatic stress experienced by males in early postnatal life impairs memory in their offspring, blocks long-term potentiation (LTP) and favors long-term depression (LTD). These effects are accompanied by suppression of key molecular pathways involved in neuronal plasticity both at rest and after acute stress. Male mice were exposed to chronic traumatic stress in early postnatal life and were later bred to naM-CM-/ve females to produce second-generation offspring. Memory performance was evaluated in the offspring, and synaptic plasticity was examined in the hippocampus and the amygdala, brain areas important for memory formation. The two groups tested were 1: offspring of fathers which were stressed (MSUS - maternal separation unpredictable stress) and 2: offspring of non-stressed fathers (control). Genome-wide gene expression in hippocampus of these two groups was assessed at rest and after acute stress (this study).
Project description:We show that traumatic stress experienced by males in early postnatal life impairs memory in their offspring, blocks long-term potentiation (LTP) and favors long-term depression (LTD). These effects are accompanied by suppression of key molecular pathways involved in neuronal plasticity both at rest and after acute stress. Male mice were exposed to chronic traumatic stress in early postnatal life and were later bred to naM-CM-/ve females to produce second-generation offspring. Memory performance was evaluated in the offspring, and synaptic plasticity was examined in the hippocampus and the amygdala, brain areas important for memory formation. The two groups tested were 1: offspring of fathers which were stressed (MSUS - maternal separation unpredictable stress) and 2: offspring of non-stressed fathers (control). Genome-wide gene expression in hippocampus of these two groups was assessed at rest (this study) and after acute stress.
Project description:Mice representing phenotypic extremes of airway hyperreactivity and goblet cell metaplasia post-Sendai virus infection were identified from a 500 mouse F2 cohort (CB6F2/J). Whole lung RNA from 3 mice at each extreme was analyzed via microarray for gene expression. Subsequent pairwise comparisons between arrays allowed the identification of genes differentially expressed with respect to the disease phenotypes (airway hyperreactivity and goblet cell metaplasia).
Project description:Traditional Chinese Medicine (TCM) has been used for thousands of years to treat or prevent diseases, including cancer. Good manufacturing practices (GMP) and sophisticated product analysis (PhytomicsQC) to ensure consistency are now available allowing the assessment of its utility. Polychemical Medicines, like TCM, include chemicals with distinct tissue-dependent pharmacodynamic properties that result in tissue-specific bioactivity. Determining the mode of action of these mixtures was previously unsatisfactory; however, information rich RNA microarray technologies now allow for thorough mechanistic studies about complex mixtures effects. PHY906 is a long used four herb TCM formula employed as adjuvant to relieve side effects associated with chemotherapy. Animal studies documented a decrease in global toxicity and an increase in therapeutic effectiveness of chemotherapy when PHY906 was combined. Using a systems biology approach, we studied tumor tissue to identify reasons for the enhancement of the antitumor effect of Irinotecan by PHY-906 in a well-characterized pre-clinical model; PHY-906 and Irinotecan were administered orally to female BDF-1 mice bearing subcutaneous Colon 38 tumors. We observed that 1) individually PHY-906 and Irinotecan induce distinct alterations in tumor, liver and spleen; 2) PHY-906 alone predominantly induces repression of transcription and immune-suppression in tumors; 3) these effects are reverted in the presence of Irinotecan, with prevalent induction of pro-apoptotic and pro-inflammatory pathways that may favor tumor rejection. Most importantly, PHY-906 together with Irinotecan triggers unique changes not activated by each one alone suggesting that the combination creates a unique tissue-specific response. Four groups of BDF-1 mice bearing colon 38 tumors were treated with Phosphate Buffered Saline (PBS) (n=10), PHY-906 (n=10), Irinotecan (CPT-11, Camptosar(TM)) (n=10) or the combination PHY-906 and Irinotecan (n=10). Tumor (38 samples), spleen (38 samples), and liver (35 samples) tissues were removed and frozen for total RNA isolation and subsequent microarray hybridization. There were a total of 111 samples representing 12 treated tissue groups with 8 to 10 biological replicates each. A reference sample was generated from a pool of mixed normal mouse tissue.
Project description:LH-overexpressing mice display elevated levels of mammogenic hormones and consequently develop spontaneous mammary tumors with a median latency of 41 weeks. Tumors occur in the absence of p53 mutations and in the presence of a seemingly functional p53 signaling pathway. At 16 weeks of age, no histological evidence of tumors is observed in these transgenic mammary glands; however, mammary cells do demonstrate centrosome amplification at this age suggesting that early tumorigenic processes may have occured. Thus comparison of the transcriptome of the mammary glands from 16 week old LH-overexpressing mice to that of wild type mice will provide insight into early events occuring in p53-independent hormone-induced tumorigenesis. Experiment Overall Design: Total RNA was isolated from mammary glands of a total of 9 wild type and 9 transgenic mice. RNA from 3 mammary glands was pooled together generating 3 wild type samples and 3 transgenic samples.