We used microarrays to compare the expression profiles between brains of BCAS1 knockout and wild type mice
Mice lacking BCAS1, a novel myelin-associated protein, display hypomyelination, schizophrenia-like abnormal behaviors, and upregulation of inflammatory genes in the brain.
Sex, Specimen part
View SamplesMicroRNAs comprise 1-3% of all vertebrate genes, but their in vivo functions and mechanisms of action remain largely unknown. Zebrafish miR-430 is expressed at the onset of zygotic transcription and regulates morphogenesis during early development. Using a microarray approach and in vivo target validation, we find that miR-430 directly regulates several hundred target mRNAs. Targets are highly enriched for maternal mRNAs that accumulate in the absence of miR-430. We also show that miR-430 accelerates the deadenylation of target mRNAs. These results suggest that miR-430 facilitates the deadenylation and clearance of maternal mRNAs during early embryogenesis.
Zebrafish MiR-430 promotes deadenylation and clearance of maternal mRNAs.
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View SamplesNeuroblastoma, the most common extracranial pediatric solid tumor, is responsible for 15% of all childhood cancer deaths. Patients frequently present at diagnosis with metastatic disease, particularly to the bone marrow. Advances in therapy and understanding of the metastatic process have been limited due in part, to the lack of animal models harboring bone marrow disease. The widely employed transgenic model, the TH-MYCN mouse, exhibits limited metastasis to this site. Here we establish the first genetic immunocompetent mouse model for metastatic neuroblastoma with enhanced secondary tumors in the bone marrow. This model recapitulates two frequent alterations in metastatic neuroblasoma, over-expression of MYCN and loss of caspase-8 expression. In this model, the mouse caspase-8 gene was deleted in neural crest lineage cells by crossing a TH-Cre transgenic mouse with a caspase-8 conditional knockout mouse. This mouse was then crossed with the neuroblastoma prone TH-MYCN mouse. While over-expression of MYCN by itself rarely caused bone marrow metastasis (5% average incidence), combining MYCN overexpression and caspase-8 deletion significantly increased bone marrow metastasis (37% average incidence). Loss of caspase-8 expression did not alter the site, incidence, or latency of the primary tumors. However, secondary tumors were detected in the bone marrow of these mice as early as week 9-10. The mouse model described in this work is a valuable tool to enhance our understanding of metastatic neuroblastoma and treatment options and underscores the role of caspase-8 in neuroblastoma progression.
Th-MYCN mice with caspase-8 deficiency develop advanced neuroblastoma with bone marrow metastasis.
Specimen part
View SamplesAnalysis of mouse chondrocytes lacking the microRNA-140. MicroRNAs are genomically encoded small RNAs to regulate the gene expression. miR-140 shows high expression in cartilage. Results provide insight into the molecular mechanisms underlying miR-140 function in chondrocytes.
MicroRNA-140 plays dual roles in both cartilage development and homeostasis.
Specimen part
View SamplesHere we characterize and optimize both systems to increase their utility for preclinical studies. We show that TH-MYCN mice develop tumors in the paraspinal ganglia, but not in the adrenal, with cellular and gene expression patterns similar to human NB. In addition, we present a new ultrasound guided, non-invasive orthotopic xenograft method. This injection technique is rapid, provides accurate targeting of the injected cells and leads to efficient engraftment. We also demonstrate that tumors can be detected, monitored and quantified prior to visualization using ultrasound, MRI and bioluminescence. Finally we develop and test a standard of care chemotherapy regimen. This protocol, which is based on current treatments for neuroblastoma, provides a baseline for comparison of new therapeutic agents.
Preclinical models for neuroblastoma: establishing a baseline for treatment.
Specimen part
View SamplesTo clarify inflammatory genes whose expression is suppressed at high temperatures, we performed comprehensive analysis of gene expression by using a DNA microarray. Two independent primary cultures of mouse embryo fibroblasts (MEF1 and MEF2) were treated with LPS for 4 hours, or treated with LPS for 4 hours after the pretreatment with heat shock at 42C for 1 hour, and we identified 100 genes that undergo more than a 3-fold increase with LPS treatment. Remarkably, 86 genes (86%) underwent less than a 2-fold increase after combined treatments with heat shock and LPS in MEF1 and MEF2 cells.
Heat shock transcription factor 1 inhibits expression of IL-6 through activating transcription factor 3.
Specimen part
View SamplesMost of the genes were self-tolerized by Pam3CSK4 and MDP but there was no or minimal cross-tolerization.
The cytosolic sensors Nod1 and Nod2 are critical for bacterial recognition and host defense after exposure to Toll-like receptor ligands.
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