Whereas the cellular basis of the hematopoietic stem cell (HSC) niche in the bone marrow has been characterized, the nature of the fetal liver (FL) niche is not yet elucidated. We show that Nestin+NG2+ pericytes associate with portal vessels, forming a niche promoting HSC expansion. Nestin+NG2+ cells and HSCs scale during development with the fractal branching patterns of portal vessels, tributaries of the umbilical vein. After closure of the umbilical inlet at birth, portal vessels undergo a transition from Neuropilin-1+Ephrin-B2+ artery to EphB4+ vein phenotype, associated with a loss of peri-portal Nestin+NG2+ cells and emigration of HSCs away from portal vessels. These data support a model in which HSCs are titrated against a peri-portal vascular niche with a fractal-like organization enabled by placental circulation. Overall design: Characterization of the transcriptome of fetal liver and adult bone marrow niche using RNA-seq
Fetal liver hematopoietic stem cell niches associate with portal vessels.
Specimen part, Cell line, Subject
View SamplesDisrupted skin barrier due to altered keratinocyte differentiation is common in pathologic conditions such as atopic dermatitis, ichthyosis and psoriasis. However, the molecular cascades governing keratinocyte terminal differentiation are still poorly understood. We have previously demonstrated that a dominant mutation in ZNF750 leads to a clinical phenotype that reminiscent of psoriasis and seborrheic dermatitis. We defined ZNF750 as a nuclear effector that is strongly activated in and essential for keratinocyte terminal differentiation. ZNF750 knockdown in HaCaT keratinocytes markedly reduced the expression of epidermal late differentiation markers, including gene subsets of epidermal differentiation complex and skin barrier formation such as FLG, LOR, SPINK5, ALOX12B and DSG1, known to be mutated in various human skin diseases. Furthermore, ZNF750 over-expression in undifferentiated cells induced terminal differentiation genes. Thus, ZNF750 is a regulator of keratinocyte terminal differentiation, and with its downstream targets can serve in future elucidation of therapeutics for common disease of skin barrier
ZNF750 is expressed in differentiated keratinocytes and regulates epidermal late differentiation genes.
Specimen part
View SamplesInflammation has a causal role in many cancers. In prostate cancers, epidemiological data suggest a link between prostatitis and subsequent cancer development, but a proof for this concept in a tumor model has been lacking. A constitutively active version of the IkappaB kinase 2 (IKK2), the molecule activated by a plethora of inflammatory stimuli, was expressed specifically in the prostate epithelium. Signaling of the IKK2/NF-kappaB axis was insufficient for transformation of prostate tissue. However, while PTEN+/- epithelia exhibited intraepithelial neoplasias only recognizable by nuclear alterations, additional IKK2 activation led to an increase in tumor size and formation of cribriform structures and to a fiber increase in the fibroblastic stroma. This phenotype was coupled with inflammation in the prostate gland characterized by infiltration of granulocytes and macrophages. Molecular characterization of the tissues showed a specific loss of smooth muscle markers as well as expression of chemokines attracting immune cells. Isolation of epithelial and stromal cells showed differential chemokine expression by these cells. Correlation studies showed the inflammatory phenotype coupled to loss of smooth muscle in infiltrated glands, but maintenance of the phenotype in glands where inflammation had decreased. Despite the loss of the smooth muscle barrier, tumors were not invasive in a stable genetic background. Data mining revealed that smooth muscle markers are downregulated in human prostate cancers and literature data show that loss of these markers in primary tumors is associated with subsequent metastasis. Our data show that loss of smooth muscle and invasiveness of the tumor are not coupled. Thus, inflammation during early steps of tumorigenesis can lead to increased tumor size and a potential change in the subsequent metastatic potential, but the tumor requires an additional transformation to become a carcinoma.
Persistent inflammation leads to proliferative neoplasia and loss of smooth muscle cells in a prostate tumor model.
Age, Specimen part
View SamplesCyclin D1b is a splice variant of the cell cycle regulator Cyclin D1 and is known to harbor divergent and highly oncogenic functions in human disease. While Cyclin D1b is induced during disease progression in many cancer types, the mechanisms underlying Cyclin D1b function remain poorly understood. Herein, models of human disease were utilized to resolve the downstream pathways requisite for the pro-tumorigenic functions of Cyclin D1b. Specifically, it was shown that Cyclin D1b modulates the expression of a large transcriptional network that cooperates with AR signaling to enhance tumor cell growth and invasive potential. Notably, Cyclin D1b promoted AR-dependent activation of genes associated with metastatic phenotypes. Further exploration determined that transcriptional induction of SNAI2 (Slug) was essential for Cyclin D1b- mediated proliferative and invasive properties, implicating Slug as a critical driver of disease progression. Importantly, Cyclin D1b expression highly correlated with that of Slug in clinical samples of advanced disease. Further, in vivo analyses provided strong evidence that Slug enhances both tumor growth and homing to distal soft tissues. Collectively, these findings reveal the underpinning mechanisms behind the pro-tumorigenic functions of Cyclin D1b, and demonstrate that the convergence of the Cyclin D1b-AR and Slug pathways results in the activation of processes critical for the promotion of lethal tumor phenotypes.
Convergence of oncogenic and hormone receptor pathways promotes metastatic phenotypes.
Specimen part, Cell line
View SamplesAn understanding of the mechanisms regulating white adipose tissue (WAT) formation is key for developing of new tools to treat obesity and its related diseases. Here, we identify DEPTOR as a positive regulator of adipogenesis whose expression is associated with obesity. In a polygenic mouse model of obesity/leanness, Deptor is part of the Fob3a QTL linked to obesity and we fine that Deptor is the highest priority candidate gene regulating WAT accumulation in this model. Using a doxycycline-inducible mouse model for Deptor overexpression, we confirmed that Deptor promotes WAT expansion in vivo. DEPTOR expression is elevated in WAT of obese humans and strongly correlates with the degree of obesity. We show that DEPTOR is induced during adipogenesis and that its overexpression cell-autonomously promotes, while its suppression blocks, adipogenesis. DEPTOR positively regulates adipogenesis by promoting the activity of the pro-adipogenic factors Akt/PKB and PPAR-gamma. These results establish DEPTOR as a physiological regulator of adipogenesis and provide new insights into the molecular mechanisms controlling WAT formation.
DEPTOR cell-autonomously promotes adipogenesis, and its expression is associated with obesity.
Sex, Specimen part
View SamplesOb/ob mice were given 0, 12.5 or 25 ng/hr leptin through an osmotic pump. After 12 days, livers RNA was prepared and illumina microarrays were done. We tested whether leptin can ameliorate diabetes independent of weight loss by defining the lowest dose at which leptin treatment of ob/ob mice reduces plasma [glucose] and [insulin]. We found that a leptin dose of 12.5 ng/hour significantly lowers blood glucose and that 25 ng/hour of leptin normalizes plasma glucose and insulin without significantly reducing body weight, thus establishing that leptin exerts its most potent effects on glucose metabolism. To find possible mediators of this effect, we profiled liver mRNA using microarrays and identified IGF Binding Protein 2 as being regulated by leptin with a similarly high potency. Over-expression of IGFBP2 by an adenovirus reversed diabetes in insulin resistant ob/ob, Ay/a and diet-induced obese mice (DIO), as well as insulin deficient streptozotocin-treated mice. Hyperinsulinemic clamp studies showed a three-fold improvement in hepatic insulin sensitivity following IGFBP2 treatment in ob/ob mice. These results show that IGFBP2 can regulate glucose metabolism, a finding with potential implications for the pathogenesis and treatment of diabetes.
Antidiabetic effects of IGFBP2, a leptin-regulated gene.
Specimen part, Time
View SamplesThe goal of this study was to identify genes which are differentiatlly expresesd upon induced inactivation of Rfx6 in beta cell in adult mice Overall design: Rfx6fl/fl; Ins1-CreERT2 (mut) and Rfx6fl/fl (ctrl) 8 weeks old mice were injected subcutaneously with tamoxifen daily during 3 days. Pancreatic islets were isolated 5 days after the first injection and RNA purified.
Rfx6 maintains the functional identity of adult pancreatic β cells.
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View SamplesWe report that phosphorylated ribosomes can be immunoprecipitated from mouse brain homogenates, resulting in enrichment of transcripts expressed in activated neurons. Overall design: Mice were either injected with a concentrated salt solution or vehicle, hypothalami dissected, and phosphorylated ribosomes immunoprecipitated. RNA was sequenced from the input and IP for each condition (4 samples total).
Molecular profiling of activated neurons by phosphorylated ribosome capture.
Specimen part, Cell line, Treatment, Subject
View SamplesAnalysis of expression profiles in stage II colon cancer according to the APC gene status
Expression Profiles in Stage II Colon Cancer According to APC Gene Status.
Sex, Age, Specimen part
View SamplesCDk4/6 inhibitor activates RB and represses RB/E2F target genes
RB Loss Promotes Prostate Cancer Metastasis.
Cell line, Treatment
View Samples