Array profiling of dystrophin-deficient mice with a secondary glycosylation defect
Ontology highlight
ABSTRACT: A deletion in the CMAH gene in humans occurred approximately 3.5 million years ago. This resulted in the inactivation of the CMP-Neu5Ac hydroxylase enzyme, and hence, in the specific deficiency in N-glycolylneuraminic acid (Neu5Gc), a form of sialic acid, in all modern humans. Although there is evidence that this molecular milestone in the origin of humans may have led to the evolution of human-specific pathogens, how deficiency in Neu5Gc might alter progression of non-infectious human diseases remains unanswered. Here, we have investigated cardiac and skeletal muscle gene expression changes in mdx mice, a model of Duchenne muscular dystrophy (DMD), that do or do not carry the human-like inactivating mutation in the mouse Cmah gene. We have evidence that Neu5Gc-deficiency in humans might explain some of the discrepancies in the disease phenotype between mdx mice and DMD patients.
Project description:A deletion in the CMAH gene in humans occurred approximately 3.5 million years ago. This resulted in the inactivation of the CMP-Neu5Ac hydroxylase enzyme, and hence, in the specific deficiency in N-glycolylneuraminic acid (Neu5Gc), a form of sialic acid, in all modern humans. Although there is evidence that this molecular milestone in the origin of humans may have led to the evolution of human-specific pathogens, how deficiency in Neu5Gc might alter progression of non-infectious human diseases remains unanswered. Here, we have investigated cardiac and skeletal muscle gene expression changes in mdx mice, a model of Duchenne muscular dystrophy (DMD), that do or do not carry the human-like inactivating mutation in the mouse Cmah gene. We have evidence that Neu5Gc-deficiency in humans might explain some of the discrepancies in the disease phenotype between mdx mice and DMD patients. The study had four groups of mice: 1) Wild type, 2) Cmah KO (mice carrying a human-like mutation in the Cmah gene and hence have human-like deficiency in Neu5Gc sialic acid), 3) mdx (mouse model for Duchenne Muscular Dystrophy), and 4) mdx mice deficient in Cmah. Gene expression was studied in heart and gastrocnemius muscle samples. Three replicates per group/tissue.
Project description:N-glycolylneuraminic acid (Neu5Gc) is generated by hydroxylation of CMP-Neu5Ac to CMP-Neu5Gc, catalyzed by CMP-Neu5Ac hydroxylase (CMAH). However, humans lack this common mammalian cell surface molecule, Neu5Gc, due to inactivation of the CMAH gene during evolution. CMAH is one of several human-specific genes whose function has been lost by disruption or deletion of the coding frame. It has been suggested that CMAH inactivation has resulted in biochemical or physiological characteristics that have resulted in human-specific diseases. To identify differential gene expression profiles associated with the loss of Neu5Gc expression, we performed microarray analysis using Illumina MouseRef-8 v2 Expression BeadChip, using the main tissues (liver, lung, kidney, and heart) from a control mouse and a Cmah-null mouse.
Project description:N-glycolylneuraminic acid (Neu5Gc) is generated by hydroxylation of CMP-Neu5Ac to CMP-Neu5Gc, catalyzed by CMP-Neu5Ac hydroxylase (CMAH). However, humans lack this common mammalian cell surface molecule, Neu5Gc, due to inactivation of the CMAH gene during evolution. CMAH is one of several human-specific genes whose function has been lost by disruption or deletion of the coding frame. It has been suggested that CMAH inactivation has resulted in biochemical or physiological characteristics that have resulted in human-specific diseases. To identify differential gene expression profiles associated with the loss of Neu5Gc expression, we performed microarray analysis using Illumina MouseRef-8 v2 Expression BeadChip, using the main tissues (liver, lung, kidney, and heart) from a control mouse and a Cmah-null mouse. Total RNA was extracted and purified from the liver, lung, kidney, and heart of WT and Cmah-null mice using RNeasy columns (Qiagen; Valencia, CA, USA) according to the manufacturer’s protocol. The RNA quality was verified using an Agilent Bioanalyzer 2100 (Agilent Technologies; Palo Alto, CA, USA) using the RNA 6000 Pico Assay. Generation of double-stranded cDNA, preparation and labeling of cRNA, hybridization to Mouse Ref-8 v2.0 Expression BeadChip (Illumina, Inc.; San Diego, CA, USA), washing, and scanning were all performed according to the standard Illumina protocol. Arrays were scanned using the Illumina Bead Array Reader Confocal Scanner.
Project description:CMP-Neu5Ac hydroxylase (Cmah) disruption caused several abnormalities and diseases including hearing loss in old age. However, underling molecular mechanisms that give rise to age-related hearing loss (AHL) in Cmah-null mouse are still obscure. To identify differential gene expression profiles associated with Cmah disruption, we performed microarray analysis using Illumina MouseRef-8 v2 Expression BeadChip, using the cochlear tissues from a control mouse and a Cmah-null mouse.
Project description:Meningococcus utilizes β-arrestin selective activation of endothelial cell β2 adrenergic receptor (β2AR) to cause meningitis in humans. Molecular mechanisms of receptor activation by the pathogen and of its species selectivity remained elusive. We report that β2AR activation requires two asparagine-branched glycan chains with terminally exposed N-acetyl neuraminic acid (sialic acid, Neu5Ac) residues located at a specific distance in its N34 terminus, while being independent of surrounding amino-acid residues. Meningococcus triggers receptor signaling by exerting direct and hemodynamic-promoted traction forces on β2AR glycans. Similar activation is recapitulated with beads coated with Neu5Ac-binding lectins, submitted to mechanical stimulation. This previously unknown glycan-dependent mode of allosteric mechanical activation of a G protein-coupled receptor contributes to meningococcal species selectivity, since Neu5Ac is only abundant in humans due to the loss of CMAH, the enzyme converting Neu5Ac into N-glycolyl-neuraminic acid in other mammals. It represents an additional mechanism of evolutionary adaptation of a pathogen to its host.
Project description:CMP-Neu5Ac hydroxylase (Cmah) disruption caused several abnormalities and diseases including hearing loss in old age. However, underling molecular mechanisms that give rise to age-related hearing loss (AHL) in Cmah-null mouse are still obscure. To identify differential gene expression profiles associated with Cmah disruption, we performed microarray analysis using Illumina MouseRef-8 v2 Expression BeadChip, using the cochlear tissues from a control mouse and a Cmah-null mouse. Total RNA was extracted and purified from the cochlear tissues of WT and Cmah-null mice using RNeasy columns (Qiagen; Valencia, CA, USA) according to the manufacturer’s protocol. The RNA quality was verified using an Agilent Bioanalyzer 2100 (Agilent Technologies; Palo Alto, CA, USA) using the RNA 6000 Pico Assay. Generation of double-stranded cDNA, preparation and labeling of cRNA, hybridization to Mouse Ref-8 v2.0 Expression BeadChip (Illumina, Inc.; San Diego, CA, USA), washing, and scanning were all performed according to the standard Illumina protocol. Arrays were scanned using the Illumina Bead Array Reader Confocal Scanner.
Project description:Duchenne muscular dystrophy (DMD) is a severely debilitating and incurable neuromuscular disease. Its conspicuous feature is the absence of dystrophin in myofibers and therefore most therapeutic approaches focus on some form of its re-expression there. However, increasing body of evidence points at an early developmental onset of DMD and severe abnormalities were uncovered in dystrophic muscle stem cells. In this study, we explore gene expression changes in primary myoblasts from mice lacking expression of the full length dystrophin transcript. Total RNA extracted from primary myoblasts isolated from gastrocnemii of 8 week old male Dmd-mdx (MDX - lacking the full length dystrophin transcript), Dmd-mdx-βgeo (BGEO - lacking all dystrophin expression) and control mice (WT) were subjected to RNA sequencing following ribodepletion, and analysed for the differential expression of genes between groups and the enrichment of gene ontology categories or pathways.
Project description:Duchenne muscular dystrophy (DMD) is a classical monogenic disorder, a model disease for genomic studies and a priority candidate for regenerative medicine and gene therapy. Although the genetic cause of DMD is well known, the molecular pathogenesis of disease and the response to therapy are incompletely understood. Here, we describe analyses of protein, mRNA and microRNA expression in the tibialis anterior of the mdx mouse model of DMD. Notably, 3272 proteins were quantifiable and 525 identified as differentially expressed in mdx muscle (P < 0.01). Therapeutic restoration of dystrophin by exon skipping induced widespread shifts in protein and mRNA expression towards wild-type expression levels, whereas the miRNome was largely unaffected. Comparison analyses between datasets showed that protein and mRNA ratios were only weakly correlated (r = 0.405), and identified a multitude of differentially affected cellular pathways, upstream regulators and predicted miRNA–target interactions. This study provides fundamental new insights into gene expression and regulation in dystrophic muscle. 3 Wt, 4 mdx and 4 Pip6e-PMO treated mdx mice
Project description:Duchenne muscular dystrophy (DMD) is a classical monogenic disorder, a model disease for genomic studies and a priority candidate for regenerative medicine and gene therapy. Although the genetic cause of DMD is well known, the molecular pathogenesis of disease and the response to therapy are incompletely understood. Here,we describe analyses of protein, mRNA and microRNA expression in the tibialis anterior of the mdx mouse model of DMD. Notably, 3272 proteins were quantifiable and 525 identified as differentially expressed in mdx muscle (P < 0.01). Therapeutic restoration of dystrophin by exon skipping induced widespread shifts in protein and mRNA expression towards wild-type expression levels, whereas the miRNome was largely unaffected. Comparison analyses between datasets showed that protein and mRNA ratios were only weakly correlated (r = 0.405), and identified a multitude of differentially affected cellular pathways, upstream regulators and predicted miRNA–target interactions. This study provides fundamental new insights into gene expression and regulation in dystrophic muscle. 3 Wt, 4 mdx and 4 Pip6e-PMO treated mdx mice
Project description:We generated and analyzed a conditional Dystrophin flox52/Y: human alpha-skeletal actin muscle knockout (Dmd flox52/Y: HSA mKO) model by targeting exon 52 deletion in the Dystrophin gene to study the consequences of dystrophin loss in skeletal muscle lineages. The generated DMD mouse model ablates dystrophin protein expression after mating with a Cre recombinase transgenic mouse under the control of HSA promoter element that is restricted to the skeletal muscle. The resulting Dmd mKO mice have been assessed using histopathological, phenotypical, functional and biochemical assays based on TRET-NMD standard operating protocols (SOPs) for mdx mouse models. Phenotypic analysis of these conditional Dmd mKO mice revealed a significant decline in locomotor activity and reduced muscle force, motor and muscular function. The histochemical analysis revealed an increase in centralized myonuclei and fibrotic area similar to mdx mice. Immunoassays including western blot and immunohistochemistry confirmed low expression levels of dystrophin in skeletal muscles of Dmd mKO mice. Bulk RNA sequencing analysis revealed that dystrophin loss in myofiber significantly disrupted the expression of cytokines and extracellular matrix genes.