Project description:Background: Gq-coupled G protein-coupled receptors (GPCR) mediate the actions of a variety of messengers that are key regulators of cardiovascular function. Enhanced Gaq-mediated signaling plays an important role in cardiac hypertrophy and in the transition to heart failure. We have recently described that Gaq acts as an adaptor protein that facilitates PKCz-mediated activation of ERK5 in epithelial cells. Since the ERK5 cascade is known to be involved in cardiac hypertrophy, we have investigated the potential relevance of this pathway in Gq-dependent signaling in cardiac cells. Methodology/Principal Findings: We have explored the mechanisms involved in Gq-coupled GPCR-mediated stimulation of the ERK5 pathway and its functional consequences in cardiac hypertrophy using both cultured cardiac cells and an animal model of angiotensin- dependent induction of cardiac hypertrophy in wild-type and PKCz knockout mice. We find that PKC? is required for the activation of the ERK5 pathway by Gq-coupled GPCR in cardiomyocytes and in cardiac fibroblasts. Stimulation of ERK5 by angiotensin II is blocked upon pharmacological inhibition or siRNA-mediated silencing of PKCz in primary cultures of cardiac cells and in cardiomyocytes isolated from PKCz-deficient mice. Moreover, these mice do not develop cardiac hypertrophy upon chronic challenge with angiotensin II, as assessed by morphological, biomarker, electrocardiographic and global gene expression pattern analysis. Conclusion/Significance: Our data put forward that PKC? is essential for Gq- dependent ERK5 activation in cardiac cells and indicate a key cardiac physiological role for this recently described Gaq/PKCz/MEK5 signaling axis. Littermate wild-type and PKCz -/- male mice (32 weeks of age) were subjected to continuous infusion of angiotensin II (or PBS as a control) for 14 days, a well established model for the induction of cardiac hypertrohy
Project description:Background: Gq-coupled G protein-coupled receptors (GPCR) mediate the actions of a variety of messengers that are key regulators of cardiovascular function. Enhanced Gaq-mediated signaling plays an important role in cardiac hypertrophy and in the transition to heart failure. We have recently described that Gaq acts as an adaptor protein that facilitates PKCz-mediated activation of ERK5 in epithelial cells. Since the ERK5 cascade is known to be involved in cardiac hypertrophy, we have investigated the potential relevance of this pathway in Gq-dependent signaling in cardiac cells. Methodology/Principal Findings: We have explored the mechanisms involved in Gq-coupled GPCR-mediated stimulation of the ERK5 pathway and its functional consequences in cardiac hypertrophy using both cultured cardiac cells and an animal model of angiotensin- dependent induction of cardiac hypertrophy in wild-type and PKCz knockout mice. We find that PKCζ is required for the activation of the ERK5 pathway by Gq-coupled GPCR in cardiomyocytes and in cardiac fibroblasts. Stimulation of ERK5 by angiotensin II is blocked upon pharmacological inhibition or siRNA-mediated silencing of PKCz in primary cultures of cardiac cells and in cardiomyocytes isolated from PKCz-deficient mice. Moreover, these mice do not develop cardiac hypertrophy upon chronic challenge with angiotensin II, as assessed by morphological, biomarker, electrocardiographic and global gene expression pattern analysis. Conclusion/Significance: Our data put forward that PKCζ is essential for Gq- dependent ERK5 activation in cardiac cells and indicate a key cardiac physiological role for this recently described Gaq/PKCz/MEK5 signaling axis.
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 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: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.