Project description:A complete understanding of molecular mechanisms that underlie cancer onset and progression could provide a basis to improve early diagnosis and more effective treatment. However, this is still a challenge in human, partly due to the difficulty of analyzing the early stages of the disease. In this context, genetically engineered mice represent a valuable alternative to model human carcinogenesis. Here, we studied cancer development in c-Myc/Tgfa transgenic mice that developed liver tumors which closely reproduce a subset of human hepatocellular carcinoma (HCC) with a poor prognosis. By using a functional genomics approach from early to late stages of HCC development, we demonstrated that hepatocarcinogenesis in c-Myc/Tgfa mice resulted from a progressive accumulation of transcriptional alterations due to an active hepatocyte proliferation in a chronic oxidative stress environment generated by a general metabolic disorder. One striking observation was the deregulation of numerous immune-related genes starting from an early stage of the disease. Particularly, we showed that activating ligands for natural killer (NK) cells were specifically induced in dysplastic hepatocytes which simultaneously lost the expression of MHC-I molecules. Besides this early mechanism of NK-mediated immune surveillance, we further reported a drastic decrease in hepatic NK cell population which may indeed contribute to the emergence and clonal expansion of progenitors for liver tumors. In conclusion, our study provided a detailed and comprehensive characterization of hepatocarcinogenesis in c-Myc/Tgfa transgenic mice and emphasized the critical role of the innate immune surveillance disruption at the early stages of liver cancer. In the present study, we reported a detailed and comprehensive dynamic characterization of the cellular and molecular alterations involved in tumor onset and progression in the liver of c-Myc/Tgfa double-transgenic mice (B6CBAxCD1 background). Liver samples from male animals were collected at various time-points ranging from 3 weeks to 9 months for c-Myc/Tgfa double-transgenic mice, or 18 months for c-Myc and Tgfa single-transgenic mice. Tissue samples were divided into two parts; one was fixed in 10% formalin for histological evaluation and the other was used for RNA analysis. Total RNAs were isolated from livers with moderate or severe hepatocyte dysplasia (at 3 weeks and 3 months, respectively), as well as from HCC and surrounding non-tumor livers (5-15 mice per group). Total RNAs were also isolated from the livers of B6CBAxCD1 wild-type mice at 3 weeks and 3 months. RNAs isolated from the normal livers of B6CBA WT mice (3 months old, n=10) were pooled and used as a common technical reference for all microarray experiments.
Project description:A complete understanding of molecular mechanisms that underlie cancer onset and progression could provide a basis to improve early diagnosis and more effective treatment. However, this is still a challenge in human, partly due to the difficulty of analyzing the early stages of the disease. In this context, genetically engineered mice represent a valuable alternative to model human carcinogenesis. Here, we studied cancer development in c-Myc/Tgfa transgenic mice that developed liver tumors which closely reproduce a subset of human hepatocellular carcinoma (HCC) with a poor prognosis. By using a functional genomics approach from early to late stages of HCC development, we demonstrated that hepatocarcinogenesis in c-Myc/Tgfa mice resulted from a progressive accumulation of transcriptional alterations due to an active hepatocyte proliferation in a chronic oxidative stress environment generated by a general metabolic disorder. One striking observation was the deregulation of numerous immune-related genes starting from an early stage of the disease. Particularly, we showed that activating ligands for natural killer (NK) cells were specifically induced in dysplastic hepatocytes which simultaneously lost the expression of MHC-I molecules. Besides this early mechanism of NK-mediated immune surveillance, we further reported a drastic decrease in hepatic NK cell population which may indeed contribute to the emergence and clonal expansion of progenitors for liver tumors. In conclusion, our study provided a detailed and comprehensive characterization of hepatocarcinogenesis in c-Myc/Tgfa transgenic mice and emphasized the critical role of the innate immune surveillance disruption at the early stages of liver cancer.
Project description:We created mice, which are deficient for Myc specifically in cardiac myocytes by crossing crossed Myc-floxed mice (Mycfl/fl) and MLC-2VCre/+ mice. Serial analysis of earlier stages of gestation revealed that Myc-deficient mice died prematurely at E13.5-14.5. Morphological analyses of E13.5 Myc-null embryos showed normal ventricular size and structure; however, decreased cardiac myocyte proliferation and increased apoptosis was observed. BrdU incorporation rates were also decreased significantly in Myc-null myocardium. Myc-null mice displayed a 3.67-fold increase in apoptotic cardiomyocytes by TUNEL assay. We examined global gene expression using oligonucleotide microarrays. Numerous genes involved in mitochondrial death pathways were dysregulated including Bnip3L and Birc2. Keywords: wildtype vs Myc-null
Project description:Double transgenic mice with hepatocyte-specific expression of AEG-1 and c-Myc show aggressive HCC compared to single transgenics. Gene expression was analyzed to understand the molecular mechanism by which AEG-1 and c-Myc cooperate to promote hepatocarcinogenesis.
Project description:Double transgenic mice with hepatocyte-specific expression of AEG-1 and c-Myc show aggressive HCC compared to single transgenics. Gene expression was analyzed to understand the molecular mechanism by which AEG-1 and c-Myc cooperate to promote hepatocarcinogenesis. Livers were collected from naïve adult mice (3 mice/group). Total RNA was extrancted and subjected to RNA-Seq.
Project description:We created mice, which are deficient for Myc specifically in cardiac myocytes by crossing crossed Myc-floxed mice (Mycfl/fl) and MLC-2VCre/+ mice. Serial analysis of earlier stages of gestation revealed that Myc-deficient mice died prematurely at E13.5-14.5. Morphological analyses of E13.5 Myc-null embryos showed normal ventricular size and structure; however, decreased cardiac myocyte proliferation and increased apoptosis was observed. BrdU incorporation rates were also decreased significantly in Myc-null myocardium. Myc-null mice displayed a 3.67-fold increase in apoptotic cardiomyocytes by TUNEL assay. We examined global gene expression using oligonucleotide microarrays. Numerous genes involved in mitochondrial death pathways were dysregulated including Bnip3L and Birc2. Hearts were taken from wide type and Myc-null Mouse embryos at E13.5 under the dissecting scope. Cardiac myocyte RNA was isolated using TRIZOL®Reagent Total RNA (100 ng) was hybridized to the Sentrix® MouseRef-8 Expression BeadChip that contains probes for ~24,000 transcripts. GeneChips were scanned using the Hewlett-Packard GeneArray Scanner G2500A. The data were analyzed with Illumina Inc. BeadStudio version 1.5.0.34 and normalized by rank invariant method.
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:We collected whole genome testis expression data from hybrid zone mice. We integrated GWAS mapping of testis expression traits and low testis weight to gain insight into the genetic basis of hybrid male sterility.
Project description:Translational research is commonly performed in the C57B6/J mouse strain, chosen for its genetic homogeneity and phenotypic uniformity. Here, we evaluate the suitability of the white-footed deer mouse (Peromyscus leucopus) as a model organism for aging research, offering a comparative analysis against C57B6/J and diversity outbred (DO) Mus musculus strains. Our study includes comparisons of body composition, skeletal muscle function, and cardiovascular parameters, shedding light on potential applications and limitations of P. leucopus in aging studies. Notably, P. leucopus exhibits distinct body composition characteristics, emphasizing reduced muscle force exertion and a unique metabolism, particularly in fat mass. Cardiovascular assessments showed changes in arterial stiffness, challenging conventional assumptions and highlighting the need for a nuanced interpretation of aging-related phenotypes. Our study also highlights inherent challenges associated with maintaining and phenotyping P. leucopus cohorts. Behavioral considerations, including anxiety-induced responses during handling and phenotyping assessment, pose obstacles in acquiring meaningful data. Moreover, the unique anatomy of P. leucopus necessitates careful adaptation of protocols designed for Mus musculus. While showcasing potential benefits, further extensive analyses across broader age ranges and larger cohorts are necessary to establish the reliability of P. leucopus as a robust and translatable model for aging studies.