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Cell Stem Cell Apr 2020The etiology of aortic aneurysms is poorly understood, but it is associated with atherosclerosis, hypercholesterolemia, and abnormal transforming growth factor β...
The etiology of aortic aneurysms is poorly understood, but it is associated with atherosclerosis, hypercholesterolemia, and abnormal transforming growth factor β (TGF-β) signaling in smooth muscle. Here, we investigated the interactions between these different factors in aortic aneurysm development and identified a key role for smooth muscle cell (SMC) reprogramming into a mesenchymal stem cell (MSC)-like state. SMC-specific ablation of TGF-β signaling in Apoe mice on a hypercholesterolemic diet led to development of aortic aneurysms exhibiting all the features of human disease, which was associated with transdifferentiation of a subset of contractile SMCs into an MSC-like intermediate state that generated osteoblasts, chondrocytes, adipocytes, and macrophages. This combination of medial SMC loss with marked increases in non-SMC aortic cell mass induced exuberant growth and dilation of the aorta, calcification and ossification of the aortic wall, and inflammation, resulting in aneurysm development.
Topics: Animals; Aorta; Aortic Aneurysm; Cellular Reprogramming; Mice; Muscle, Smooth, Vascular; Myocytes, Smooth Muscle; Transforming Growth Factor beta
PubMed: 32243809
DOI: 10.1016/j.stem.2020.02.013 -
Developmental Cell Oct 2022Smooth muscle cells (SMCs) execute important physiological functions in numerous vital organ systems, including the vascular, gastrointestinal, respiratory, and...
Smooth muscle cells (SMCs) execute important physiological functions in numerous vital organ systems, including the vascular, gastrointestinal, respiratory, and urogenital tracts. SMC differ morphologically and functionally at these different anatomical locations, but the molecular underpinnings of the differences remain poorly understood. Here, using deep single-cell RNA sequencing combined with in situ gene and protein expression analysis in four murine organs-heart, aorta, lung, and colon-we identify a molecular basis for high-level differences among vascular, visceral, and airway SMC, as well as more subtle differences between, for example, SMC in elastic and muscular arteries and zonation of elastic artery SMC along the direction of blood flow. Arterial SMC exhibit extensive organotypic heterogeneity, whereas venous SMC are similar across organs. We further identify a specific SMC subtype within the pulmonary vasculature. This comparative SMC cross-organ resource offers insight into SMC subtypes and their specific functions.
Topics: Mice; Animals; Muscle, Smooth, Vascular; Transcriptome; Myocytes, Smooth Muscle; Aorta; Cells, Cultured
PubMed: 36283392
DOI: 10.1016/j.devcel.2022.09.015 -
European Journal of Clinical... Apr 2022Aortic aneurysms (AA) are pathological dilations of the aorta, associated with an overall mortality rate up to 90% in case of rupture. In addition to dilation, the... (Review)
Review
BACKGROUND
Aortic aneurysms (AA) are pathological dilations of the aorta, associated with an overall mortality rate up to 90% in case of rupture. In addition to dilation, the aortic layers can separate by a tear within the layers, defined as aortic dissections (AD). Vascular smooth muscle cells (vSMC) are the predominant cell type within the aortic wall and dysregulation of vSMC functions contributes to AA and AD development and progression. However, since the exact underlying mechanism is poorly understood, finding potential therapeutic targets for AA and AD is challenging and surgery remains the only treatment option.
METHODS
In this review, we summarize current knowledge about vSMC functions within the aortic wall and give an overview of how vSMC functions are altered in AA and AD pathogenesis, organized per anatomical location (abdominal or thoracic aorta).
RESULTS
Important functions of vSMC in healthy or diseased conditions are apoptosis, phenotypic switch, extracellular matrix regeneration and degradation, proliferation and contractility. Stressors within the aortic wall, including inflammatory cell infiltration and (epi)genetic changes, modulate vSMC functions and cause disturbance of processes within vSMC, such as changes in TGF-β signalling and regulatory RNA expression.
CONCLUSION
This review underscores a central role of vSMC dysfunction in abdominal and thoracic AA and AD development and progression. Further research focused on vSMC dysfunction in the aortic wall is necessary to find potential targets for noninvasive AA and AD treatment options.
Topics: Aortic Dissection; Animals; Aortic Aneurysm; Humans; Muscle, Smooth, Vascular; Myocytes, Smooth Muscle
PubMed: 34698377
DOI: 10.1111/eci.13697 -
American Journal of Physiology. Cell... Mar 2020Rat L6, mouse C2C12, and primary human skeletal muscle cells (HSMCs) are commonly used to study biological processes in skeletal muscle, and experimental data on these... (Comparative Study)
Comparative Study
Rat L6, mouse C2C12, and primary human skeletal muscle cells (HSMCs) are commonly used to study biological processes in skeletal muscle, and experimental data on these models are abundant. However, consistently matched experimental data are scarce, and comparisons between the different cell types and adult tissue are problematic. We hypothesized that metabolic differences between these cellular models may be reflected at the mRNA level. Publicly available data sets were used to profile mRNA levels in myotubes and skeletal muscle tissues. L6, C2C12, and HSMC myotubes were assessed for proliferation, glucose uptake, glycogen synthesis, mitochondrial activity, and substrate oxidation, as well as the response to in vitro contraction. Transcriptomic profiling revealed that mRNA of genes coding for actin and myosin was enriched in C2C12, whereas L6 myotubes had the highest levels of genes encoding glucose transporters and the five complexes of the mitochondrial electron transport chain. Consistently, insulin-stimulated glucose uptake and oxidative capacity were greatest in L6 myotubes. Insulin-induced glycogen synthesis was highest in HSMCs, but C2C12 myotubes had higher baseline glucose oxidation. All models responded to electrical pulse stimulation-induced glucose uptake and gene expression but in a slightly different manner. Our analysis reveals a great degree of heterogeneity in the transcriptomic and metabolic profiles of L6, C2C12, or primary human myotubes. Based on these distinct signatures, we provide recommendations for the appropriate use of these models depending on scientific hypotheses and biological relevance.
Topics: Adult; Animals; Cell Line; Cell Proliferation; Cells, Cultured; Energy Metabolism; Gene Expression Profiling; Humans; Male; Mice; Middle Aged; Muscle Cells; Muscle Fibers, Skeletal; Muscle, Skeletal; Rats; Species Specificity; Transcriptome
PubMed: 31825657
DOI: 10.1152/ajpcell.00540.2019 -
Annals of Surgery Sep 2022To determine cell-specific gene expression profiles that contribute to development of abdominal aortic aneurysms (AAAs).
OBJECTIVE
To determine cell-specific gene expression profiles that contribute to development of abdominal aortic aneurysms (AAAs).
BACKGROUND
AAAs represent the most common pathological aortic dilation leading to the fatal consequence of aortic rupture. Both immune and structural cells contribute to aortic degeneration, however, gene specific alterations in these cellular subsets are poorly understood.
METHODS
We performed single-cell RNA sequencing (scRNA-seq) analysis of AAAs and control tissues. AAA-related changes were examined by comparing gene expression profiles as well as detailed receptor-ligand interactions. An integrative analysis of scRNA-seq data with large genome-wide association study data was conducted to identify genes critical for AAA development.
RESULTS
Using scRNA-seq we provide the first comprehensive characterization of the cellular landscape in human AAA tissues. Unbiased clustering analysis of transcriptional profiles identified seventeen clusters representing 8 cell lineages. For immune cells, clustering analysis identified 4 T-cell and 5 monocyte/macrophage subpopulations, with distinct transcriptional profiles in AAAs compared to controls. Gene enrichment analysis on immune subsets identified multiple pathways only expressed in AAA tissue, including those involved in mitochondrial dysfunction, proliferation, and cytokine secretion. Moreover, receptor-ligand analysis defined robust interactions between vascular smooth muscle cells and myeloid populations in AAA tissues. Lastly, integrated analysis of scRNA-seq data with genome-wide association study studies determined that vascular smooth muscle cell expression of SORT1 is critical for maintaining normal aortic wall function.
CONCLUSIONS
Here we provide the first comprehensive evaluation of single-cell composition of the abdominal aortic wall and reveal how the gene expression landscape is altered in human AAAs.
Topics: Aorta, Abdominal; Aortic Aneurysm, Abdominal; Genome-Wide Association Study; Humans; Ligands; Myocytes, Smooth Muscle; Transcriptome
PubMed: 35762613
DOI: 10.1097/SLA.0000000000005551 -
International Journal of Molecular... Jun 2020Millions of patients worldwide suffer from gastrointestinal (GI) motility disorders such as gastroparesis. These disorders typically include debilitating symptoms, such... (Review)
Review
Millions of patients worldwide suffer from gastrointestinal (GI) motility disorders such as gastroparesis. These disorders typically include debilitating symptoms, such as chronic nausea and vomiting. As no cures are currently available, clinical care is limited to symptom management, while the underlying causes of impaired GI motility remain unaddressed. The efficient movement of contents through the GI tract is facilitated by peristalsis. These rhythmic slow waves of GI muscle contraction are mediated by several cell types, including smooth muscle cells, enteric neurons, telocytes, and specialised gut pacemaker cells called interstitial cells of Cajal (ICC). As ICC dysfunction or loss has been implicated in several GI motility disorders, ICC represent a potentially valuable therapeutic target. Due to their availability, murine ICC have been extensively studied at the molecular level using both normal and diseased GI tissue. In contrast, relatively little is known about the biology of human ICC or their involvement in GI disease pathogenesis. Here, we demonstrate human gastric tissue as a source of primary human cells with ICC phenotype. Further characterisation of these cells will provide new insights into human GI biology, with the potential for developing novel therapies to address the fundamental causes of GI dysmotility.
Topics: Gastrointestinal Diseases; Gastrointestinal Motility; Gastrointestinal Tract; Humans; Interstitial Cells of Cajal; Intestine, Small; Myocytes, Smooth Muscle; Peristalsis; Stomach
PubMed: 32630607
DOI: 10.3390/ijms21124540 -
Arteriosclerosis, Thrombosis, and... Mar 2018The vascular system forms as a branching network of endothelial cells that acquire identity as arterial, venous, hemogenic, or lymphatic. Endothelial specification... (Review)
Review
The vascular system forms as a branching network of endothelial cells that acquire identity as arterial, venous, hemogenic, or lymphatic. Endothelial specification depends on gene targets transcribed by Ets domain-containing factors, including Ets variant gene 2 (Etv2), together with the activity of chromatin-remodeling complexes containing Brahma-related gene-1 (Brg1). Once specified and assembled into vessels, mechanisms regulating lumen diameter and axial growth ensure that the structure of the branching vascular network matches the need for perfusion of target tissues. In addition, blood vessels provide important morphogenic cues that guide or direct the development of organs forming around them. As the embryo grows and lumen diameters increase, smooth muscle cells wrap around the nascent vessel walls to provide mechanical strength and vasomotor control of the circulation. Increasing mechanical stretch and wall strain promote smooth muscle cell differentiation via coupling of actin cytoskeletal remodeling to myocardin and serum response factor-dependent transcription. Remodeling of artery walls by developmental signaling pathways reappears in postnatal blood vessels during physiological and pathological adaptation to vessel wall injury, inflammation, or chronic hypoxia. Recent reports providing insights into major steps in vascular development are reviewed here with a particular emphasis on studies that have been recently published in
Topics: Animals; Arteries; Cell Communication; Cell Differentiation; Cell Lineage; Endothelial Cells; Gene Expression Regulation, Developmental; Humans; Myocytes, Smooth Muscle; Neovascularization, Physiologic; Phenotype; Signal Transduction
PubMed: 29467221
DOI: 10.1161/ATVBAHA.118.310223 -
Experimental & Molecular Medicine Sep 2018Physical activity has many beneficial effects on metabolic disorders, such as obesity, insulin resistance, and diabetes. Meteorin-like protein (METRNL), a novel secreted...
Physical activity has many beneficial effects on metabolic disorders, such as obesity, insulin resistance, and diabetes. Meteorin-like protein (METRNL), a novel secreted protein homologous to the neurotrophin Metrn, is induced after exercise in the skeletal muscle. Herein, we investigated the effects of METRNL on lipid-mediated inflammation and insulin resistance in skeletal muscle via AMP-activated protein kinase (AMPK) or peroxisome proliferator-activated receptor δ (PPARδ). Treatment with METRNL suppressed inflammatory markers, such as nuclear factor κB (NFκB) nuclear translocation, inhibitory κBα (IκBα) phosphorylation, interleukin-6 (IL-6) expression, and pro-inflammatory cytokines (such as TNFα and MCP-1). METRNL treatment also attenuated the impaired insulin response both in palmitate-treated differentiated C2C12 cells and the skeletal muscle of high-fat diet (HFD)-fed mice. Furthermore, METRNL administration rescued glucose intolerance and reduced HFD-induced body weight gain in mice; however, METRNL did not affect calorie intake. METRNL treatment increased AMPK phosphorylation and PPARδ expression both in differentiated C2C12 cells and mouse skeletal muscle. siRNA-mediated suppression of AMPK and PPARδ abrogated the suppressive effects of METRNL on palmitate-induced inflammation and insulin resistance. Moreover, METRNL augmented the mRNA expression of fatty acid oxidation-associated genes, such as carnitine palmitoyltransferase 1 (CPT1), acyl-CoA oxidase (ACO), and fatty acid binding protein 3 (FABP3). siRNAs for AMPK and PPARδ reversed these changes. In the current study, we report for the first time that METRNL alleviates inflammation and insulin resistance and induces fatty acid oxidation through AMPK or PPARδ-dependent signaling in skeletal muscle.
Topics: AMP-Activated Protein Kinases; Animals; Cell Differentiation; Cell Line; Diet, High-Fat; Endoplasmic Reticulum Stress; Hyperlipidemias; Inflammation; Insulin Resistance; Lipids; Male; Mice, Inbred C57BL; Muscle Cells; Muscle, Skeletal; Nerve Growth Factors; PPAR delta; Palmitic Acid; Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha; Signal Transduction
PubMed: 30213948
DOI: 10.1038/s12276-018-0147-5 -
The FEBS Journal Nov 2022Regeneration of the mammalian adult skeletal muscle is a well-orchestrated process regulated by multiple proteins and signalling pathways. Cytokines constitute a major... (Review)
Review
Regeneration of the mammalian adult skeletal muscle is a well-orchestrated process regulated by multiple proteins and signalling pathways. Cytokines constitute a major class of regulators of skeletal myogenesis. It is well established that infiltrating immune cells at the site of muscle injury secrete cytokines, which play critical roles in the myofibre repair and regeneration process. In the past 10-15 years, skeletal muscle itself has emerged as a prolific producer of cytokines. Much attention in the field has been focused on the endocrine effects of muscle-secreted cytokines (myokines) on metabolic regulation. However, ample evidence suggests that muscle-derived cytokines also regulate myogenic differentiation and muscle regeneration in an autocrine manner. In this review, we survey cytokines that meet two criteria: (a) evidence of expression by muscle cells; (b) evidence demonstrating a myogenic function. Dozens of cytokines representing several major classes make up this group, and together they regulate all steps of the myogenic process. How such a large array of cytokines coordinate their signalling to form a regulatory network is a fascinating, pressing question. Functional studies that can distinguish the source of the cytokines in vivo are also much needed in order to facilitate exploration of their full therapeutic potential.
Topics: Animals; Cell Differentiation; Cytokines; Mammals; Muscle Cells; Muscle Development; Muscle, Skeletal; Regeneration
PubMed: 35073461
DOI: 10.1111/febs.16372 -
Food Research International (Ottawa,... Oct 2023Cultivated meat production requires an efficient, robust and highly optimized serum-free cell culture media for the needed upscaling of muscle cell expansion. Existing...
Cultivated meat production requires an efficient, robust and highly optimized serum-free cell culture media for the needed upscaling of muscle cell expansion. Existing formulations of serum-free media are complex, expensive and have not been optimized for muscle cells. Thus, we undertook this work to develop a simple and robust serum-free media for the proliferation of bovine satellite cells (SCs) through Design of Experiment (DOE) and Response Surface Methodology (RSM) using precise and high-throughput image-based cytometry. Proliferative attributes were investigated with transcriptomics and long-term performance was validated using multiple live assays. Here we formulated a media based on three highly optimized components; FGF2 (2 ng/mL), fetuin (600 µg/mL) and BSA (75 µg/mL) which together with an insulin-transferrin-selenium (1x) supplement, sustained the proliferation of bovine SCs, porcine SCs and murine C2C12 muscle cells. Remarkably, cells cultured in our media named Tri-basal 2.0+ performed better than cell cultured in 10% FBS, with respect to proliferation. Hence, the optimized Tri-basal 2.0+ enhanced serum-free cell attachment and long-term proliferation, providing an alternative solution to the use of FBS in the production of cultivated meat.
Topics: Animals; Cattle; Mice; Swine; Culture Media, Serum-Free; Muscle Cells; Muscles; Biological Assay; Cell Proliferation
PubMed: 37689947
DOI: 10.1016/j.foodres.2023.113194