Imbalances in glucose and energy homeostasis are at the core of the worldwide epidemic of obesity and diabetes. Here, we illustrate an important role of the TGF-beta/Smad3 signaling pathway in regulating glucose and energy homeostasis. Smad3 deficient mice are protected from diet-induced obesity and diabetes. Interestingly, the metabolic protection is accompanied by Smad3-/- white adipose tissue acquiring the bioenergetic and gene expression profile of brown fat/skeletal muscle. Smad3-/- adipocytes demonstrate a marked increase in mitochondrial biogenesis, with a corresponding increase in basal respiration, and Smad3 acts as a repressor of PGC-alpha1 expression. We observe significant correlation between TGF-beta1 levels and adiposity in rodents and humans. Further, systemic blockade of TGF-beta1 signaling protects mice from obesity, diabetes and hepatic steatosis. Together, these results demonstrate that TGF-beta signaling regulates glucose tolerance and energy homeostasis and suggest that modulation of TGF-beta1 activity might be an effective treatment strategy for obesity and diabetes.
Protection from obesity and diabetes by blockade of TGF-β/Smad3 signaling.
Treatment
View SamplesThe lung host immune responses following M.tuberculosis infection in the mouse model of tuberculosis were assayed by studying the gene expression profiles at day 0, day 12, 15 and 21 post infection
Profiling early lung immune responses in the mouse model of tuberculosis.
Specimen part, Time
View SamplesWe hypothesize that gene expression in the CS-exposed lungs of this strain (A/J) of mice would be able to give clues about the molecular mechanism of emphysema development, thus contributing to this phenotype. More specifically, although imbalance in oxidants/antioxidants and proteinase/antiproteinase pathways drives the pathogenesis of COPD, the molecular mechanisms involved in the development of emphysema are poorly understood. In order to test this hypothesis at the gene expression level, we utilized microarray analysis to examine transcriptional differences between CS-exposed and Air-exposed groups of mice.
Cigarette smoke-induced emphysema in A/J mice is associated with pulmonary oxidative stress, apoptosis of lung cells, and global alterations in gene expression.
Sex, Age, Specimen part
View SamplesMutations in the PTEN, TP53 and RB1 pathways are obligate events in the pathogenesis of human glioblastomas, the highest grade of astrocytoma. To investigate synergy between these tumor suppressors in mice, we induced various combinations of compound deletions conditionally in astrocytes and neural precursors in the mature brain. The resulting highly penetrant astrocytomas showed a spectrum of histopathological variation reminiscent of human tumors, and ranged from grade III to grade IV (glioblastoma). Secondary somatic mutations varied depending on the combination of initiating deletions and were relevant to human disease. Receptor tyrosine kinase amplifications were frequent in tumors initiated by combined conditional deletion of Pten and Tp53, but not when Rb, Pten and Tp53 were simultaneously deleted. Multiple mutations within PI3K and Rb pathways were acquired, however, Mapk activation was not consistently detected in astrocytomas. Gene expression profiling revealed striking similarities to previously described human astrocytoma subclasses. A subset of astrocytomas initiated outside of proliferative niches in the adult brain.
Cooperativity within and among Pten, p53, and Rb pathways induces high-grade astrocytoma in adult brain.
Sex, Specimen part
View SamplesHepatoblastoma (HB) is the most common pediatric liver tumor, and there are no targeted therapies available for children with HB. We have previously developed a murine model of HB which is driven by coactivation of the oncogenes YAP1 and -catenin (CTNNB1) [Tao J, Calvisi D, Ranganathan S, et al. Gastroenterology, 2014 Sep; 147(3): 690701]. We used the Sleeping Beauty transposase system combined with hydrodynamic tail vein injection to deliver plasmids containing mutant activated forms of YAP1 (YAP S127A) and -catenin (N90 -catenin) to a small number of pericentral hepatocytes. We have shown that these few transformed hepatocytes proliferate and dedifferentiate, eventually forming histologically heterogeneous tumors that resemble various subtypes of human HB (which is also highly heterogeneous), including areas of well-differentiated fetal, crowded fetal, embryonal, and blastemal HB. Our goal was to investigate how coactivation of YAP1 and -catenin drive the dedifferentiation of hepatocytes into hepatoblast-like tumor cells over time, leading to HB tumors. In order to measure changes in gene expression during tumorigenesis in our model, we used an Affymetrix microarray to analyze isolated RNA from wild type FVB mouse livers, mouse HB tumor tissue, and non-tumor liver tissue adjacent to HB tumors.
Hepatocyte-Derived Lipocalin 2 Is a Potential Serum Biomarker Reflecting Tumor Burden in Hepatoblastoma.
Age, Specimen part
View SamplesMurine models have been valuable instruments in defining the pathogenesis of diabetic nephropathy (DN), but they only partially recapitulate disease manifestations of human DN, limiting their utility . In order to define the molecular similarities and differences between human and murine DN, we performed a cross-species comparison of glomerular transcriptional networks. Glomerular gene expression was profiled in patients with early type 2 DN and in three mouse models (streptozotocin DBA/2 mice, db/db C57BLKS, and eNOS-deficient C57BLKS db/db mice). Species-specific transcriptional networks were generated and compared with a novel network-matching algorithm. Three shared, human-mouse cross-species glomerular transcriptional networks containing 143 (Human-STZ), 97 (Human- db/db), and 162 (Human- eNOS-/- db/db) gene nodes were generated. Shared nodes across all networks reflected established pathogenic mechanisms of diabetic complications, such as elements of JAK-STAT and VEGFR signaling pathways . In addition, novel pathways not formally associated with DN and cross-species gene nodes and pathways unique to each of the human-mouse networks were discovered. The human-mouse shared glomerular transcriptional networks will assist DN researchers in the selection of mouse models most relevant to the human disease process of interest. Moreover, they will allow identification of new pathways shared between mice and humans.
Identification of cross-species shared transcriptional networks of diabetic nephropathy in human and mouse glomeruli.
Age, Specimen part, Disease, Disease stage, Treatment
View SamplesPPAR is known for its anti-inflammatory actions in macrophages. However, which macrophage populations express PPAR in vivo and how it regulates tissue homeostasis in the steady state and during inflammation is not completely understood. We show that lung and spleen macrophages constitutively expressed PPAR, while other macrophage populations did not. Recruitment of monocytes to sites of inflammation was associated with induction of PPAR as they differentiated to macrophages. Its absence in these macrophages led to failed resolution of inflammation, characterized by persistent, low-level recruitment of leukocytes. Conversely, PPAR agonists supported an earlier cessation in leukocyte recruitment during resolution of acute inflammation and likewise suppressed monocyte recruitment to chronically inflamed atherosclerotic vessels. In the steady state, PPAR deficiency in macrophages had no obvious impact in the spleen but profoundly altered cellular lipid homeostasis in lung macrophages. Reminiscent of pulmonary alveolar proteinosis, LysM-Cre x PPARflox/flox mice displayed mild leukocytic inflammation in the steady-state lung and succumbed faster to mortality upon infection with S. pneumoniae. Surprisingly, this mortality was not due to overly exuberant inflammation, but instead to impaired bacterial clearance. Thus, in addition to its anti-inflammatory role in promoting resolution of inflammation, PPAR sustains functionality in lung macrophages and thereby has a pivotal role in supporting pulmonary host defense.
Systemic analysis of PPARγ in mouse macrophage populations reveals marked diversity in expression with critical roles in resolution of inflammation and airway immunity.
Sex, Treatment
View SamplesHuman and mouse blood each contain two monocyte subsets. Here, we investigated the extent of their similarity using a microarray approach. Approximately 300 genes in human and 550 genes in mouse were differentially expressed between subsets. More than 130 of these gene expression differences were conserved between mouse and human monocyte subsets. We confirmed numerous differences at the cell surface protein level. Despite overall conservation, some molecules were conversely expressed between the two species subsets, including CD36, CD9, and TREM-1. Furthermore, other differences existed, including a prominent PPAR signature in mouse monocytes absent in human. Overall, human and mouse monocyte subsets are far more broadly conserved than currently recognized. Thus, studies in mice may indeed yield relevant information regarding the biology of human monocyte subsets. However, differences between the species deserve consideration in models of human disease studied in the mouse.
Comparison of gene expression profiles between human and mouse monocyte subsets.
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Age- and pregnancy-associated DNA methylation changes in mammary epithelial cells.
Sex, Age, Specimen part
View SamplesMouse aorta smooth muscle cells (SMCs) express TNF receptor superfamily member 1A (TNFR1) and lymphotoxin receptor (LTR). Circumstantial evidence has linked the SMC LTR to tertiary lymphoid organogenesis in diseased aortae of hyperlipidemic mice. Here, we explored potential roles of TNFR1 and LTR activation in cultured SMCs. TNFR1 signaling by TNF activated the classical RelA NF-B pathway, whereas LTR signaling by agonistic anti LTR antibody activated both the classical RelA and alternative RelB NF-B pathways. Addition of both agonists synergized to enhance p100 inhibitor processing to the p52 subunit of NF-B and promoted its nuclear translocation suggesting RelA-RelB cross-talk in transcription regulation. Correspondingly, microarrays showed that simultaneous TNFR1 and LTR activation when compared to activation of single receptors was followed by markedly elevated levels of mRNAs encoding leukocyte homeostatic chemokines CCL2, CCL5, CXCL1, and CX3CL1. Furthermore, SMCs acquired prototypical features of mesenchymal cells known as lymphoid tissue organizers (LTOs), which control tertiary lymphoid organogenesis in autoimmune diseases, through hyperinduction of CCL7, CCL9, CXCL13, CCL19, CXCL16, VCAM-1, and ICAM-1. Experiments with ltbr-/- SMCs suggested that the LTR-RelB activation component of NF-B signaling was obligatory to generate the LTO phenotype. TNFR1-LTR crosstalk also resulted in augmented synthesis and prolonged secretion of lymphorganogenic chemokine proteins into the culture medium. Thus, combined TNFR1-LTR signaling triggers SMC transdifferentiation into a phenotype that strikingly resembles LTOs. LTO-like SMCs may adopt a thus far unrecognized role in diseased arteries, i.e. to coordinate tertiary lymphoid organogenesis in atherosclerosis, aortic aneurysm, and transplant vasculopathy.
Mouse aorta smooth muscle cells differentiate into lymphoid tissue organizer-like cells on combined tumor necrosis factor receptor-1/lymphotoxin beta-receptor NF-kappaB signaling.
No sample metadata fields
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