Project description:This SuperSeries is composed of the following subset Series: GSE32364: Murine blood monocyte subsets GSE32370: Regulation of monocyte functional heterogeneity by miR-146a Refer to individual Series
Project description:Monocytes and their lineage descendants serve as a central defense system against infection and injury but if uncontrolled can also promote an excessive pathological inflammatory response. Therefore a current research goal is to understand how the organism controls the number and function of monocytes and how these variables can be tailored in therapy. Considering the evidence that monocytes are heterogeneous and exist in at least two subsets committed to divergent functions, we investigated whether distinct factors regulate the balance between monocyte subset responses in vivo. We identified a microRNA (miRNA), miR-146a, which is differentially regulated both in mouse (Ly-6Chi and Ly-6Clo) and human (CD14hi and CD14lo CD16+) monocyte subsets. The single miRNA was found to significantly control the amplitude of the Ly-6Chi monocyte response during inflammatory challenge whereas it did not affect Ly-6Clo cells. miR-146a–mediated regulation was cell-intrinsic and depended on Relb, a member of the non-canonical NF-κB/Rel family, which is identified here as a novel miR-146a target. These observations provide novel mechanistic insights into the molecular events that regulate monocyte functional heterogeneity and identify therapeutic targets that can influence the quality and quantity of monocyte responses.
Project description:Monocytes and their lineage descendants serve as a central defense system against infection and injury but if uncontrolled can also promote an excessive pathological inflammatory response. Therefore a current research goal is to understand how the organism controls the number and function of monocytes and how these variables can be tailored in therapy. Considering the evidence that monocytes are heterogeneous and exist in at least two subsets committed to divergent functions, we investigated whether distinct factors regulate the balance between monocyte subset responses in vivo. We identified a microRNA (miRNA), miR-146a, which is differentially regulated both in mouse (Ly-6Chi and Ly-6Clo) and human (CD14hi and CD14lo CD16+) monocyte subsets. The single miRNA was found to significantly control the amplitude of the Ly-6Chi monocyte response during inflammatory challenge whereas it did not affect Ly-6Clo cells. miR-146a–mediated regulation was cell-intrinsic and depended on Relb, a member of the non-canonical NF-κB/Rel family, which is identified here as a novel miR-146a target. These observations provide novel mechanistic insights into the molecular events that regulate monocyte functional heterogeneity and identify therapeutic targets that can influence the quality and quantity of monocyte responses. 4 samples of splenic Ly-6Chi monocytes, 4 samples of splenic Ly-6Clo monocytes; both isolated from C57BL/6 mice. Each sample was generated by fluorecsence activated cell sorting from the pooled spleens of 10 mice.
Project description:To gain insight into the mechanisms underlying miR-146a-mediated modulation of Ly6Chigh monocyte function, we compared the expression profiles of Ly6Chigh and Ly6Clow monocytes in miR-146a+/+ (WT) versus miR-146a-/- (KO) conditions.
Project description:Introgressed variants from other species can be an important source of genetic variation because they may arise rapidly, can include multiple mutations on a single haplotype, and have often been pretested by selection in the species of origin. Although introgressed alleles are generally deleterious, several studies have reported introgression as the source of adaptive alleles-including the rodenticide-resistant variant of Vkorc1 that introgressed from Mus spretus into European populations of Mus musculus domesticus. Here, we conducted bidirectional genome scans to characterize introgressed regions into one wild population of M. spretus from Spain and three wild populations of M. m. domesticus from France, Germany, and Iran. Despite the fact that these species show considerable intrinsic postzygotic reproductive isolation, introgression was observed in all individuals, including in the M. musculus reference genome (GRCm38). Mus spretus individuals had a greater proportion of introgression compared with M. m. domesticus, and within M. m. domesticus, the proportion of introgression decreased with geographic distance from the area of sympatry. Introgression was observed on all autosomes for both species, but not on the X-chromosome in M. m. domesticus, consistent with known X-linked hybrid sterility and inviability genes that have been mapped to the M. spretus X-chromosome. Tract lengths were generally short with a few outliers of up to 2.7 Mb. Interestingly, the longest introgressed tracts were in olfactory receptor regions, and introgressed tracts were significantly enriched for olfactory receptor genes in both species, suggesting that introgression may be a source of functional novelty even between species with high barriers to gene flow.
Project description:The Epstein Barr virus (EBV) encoded latent membrane protein-1 (LMP1) is a functional homologue of the tumor necrosis factor receptor family and contributes substantially to the oncogenic potential of EBV through activation of Nuclear Factor-kappaB (NF-kappaB). MicroRNAs (miRNAs) are a class of small RNA molecules that are involved in the regulation of cellular processes such as growth, development, and apoptosis, and have recently been linked to cancer phenotypes. Through miRNA microarray analysis, we demonstrate that LMP1 dysregulates the expression of several cellular miRNAs, including the most highly regulated of these, miR-146a. Quantitative RT-PCR analysis confirmed induced expression of miR-146a by LMP1. Analysis of miR-146a expression in EBV latency type III and type I cell lines revealed substantial expression of miR-146a in type III (which express LMP1) but not in type I cell lines. Reporter studies demonstrated that LMP1 induces miR-146a predominantly through two NF-kappaB binding sites in the miR-146a promoter and identified a role for an OCT-1 site in conferring basal and induced expression. Array analysis of cellular mRNAs expressed in Akata cells transduced with an miR-146a expressing retrovirus identified genes that are directly or indirectly regulated by miR-146a, including a group of interferon responsive genes that are inhibited by miR-146a. Since miR-146a is known to be induced by agents that activate the interferon response pathway (including LMP1), these results suggest that miR-146a functions in a negative feedback loop to modulate the intensity and/or duration of the interferon response. Keywords: microRNA expression modified by EBV encoded oncogene, LMP1
Project description:The tumor suppressor p53 is the most frequently mutated gene in human cancers, mutated in 25-30% of breast cancers. However, mutation rates differ according to breast cancer subtype, being more prevalent in aggressive estrogen receptor (ER) negative tumors, basal-like and HER2 amplified subtypes. This heterogeneity suggests that p53 may function differently across breast cancer subtypes. We used RNAi-mediated p53 knockdown (KD) and antagomir-mediated KD of microRNAs to study how gene expression and cellular response to p53 loss differ in luminal vs. basal-like breast cancer. As expected, p53 loss caused down regulation of established p53 targets (e.g. p21 and miR-34 family) and increased proliferation in both luminal and basal-like cell lines. However, some p53-dependent changes were subtype-specific, including expression of miR-134, miR-146a, and miR-181b. To study the cellular response to miR-146a upregulation in p53-impaired basal-like lines, antagomir knockdown of miR-146a was performed. KD of miR-146a caused decreased proliferation and increased apoptosis, effectively ablating the effects of p53 loss. Furthermore, we found that miR-146a upregulation decreased NF-kB expression and downregulated the NF-kB-dependent extrinsic apoptotic pathway (including TNF, FADD, and TRADD) and antagomir-mediated miR-146a KD restored expression of these components, suggesting a plausible mechanism for miR-146a-dependent cellular responses. These findings are relevant to human basal-like tumor progression in vivo, since miR-146a is highly expressed in p53-mutant basal-like breast cancers. These findings suggest that targeting miR-146a expression may have value for altering the aggressiveness of p53 mutant basal-like tumors. reference x sample