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Pflugers Archiv : European Journal of... Dec 2023Cell contraction plays an important role in many physiological and pathophysiological processes. This includes functions in skeletal, heart, and smooth muscle cells,... (Review)
Review
Cell contraction plays an important role in many physiological and pathophysiological processes. This includes functions in skeletal, heart, and smooth muscle cells, which lead to highly coordinated contractions of multicellular assemblies, and functions in non-muscle cells, which are often highly localized in subcellular regions and transient in time. While the regulatory processes that control cell contraction in muscle cells are well understood, much less is known about cell contraction in non-muscle cells. In this review, we focus on the mechanisms that control cell contraction in space and time in non-muscle cells, and how they can be investigated by light-based methods. The review particularly focusses on signal networks and cytoskeletal components that together control subcellular contraction patterns to perform functions on the level of cells and tissues, such as directional migration and multicellular rearrangements during development. Key features of light-based methods that enable highly local and fast perturbations are highlighted, and how experimental strategies can capitalize on these features to uncover causal relationships in the complex signal networks that control cell contraction.
Topics: Muscle, Smooth; Muscle Contraction; Myocytes, Smooth Muscle; Phosphorylation
PubMed: 37851146
DOI: 10.1007/s00424-023-02864-2 -
Arteriosclerosis, Thrombosis, and... Apr 2022Most acute cardiovascular events are due to plaque rupture, with atheromas containing large necrotic cores and thin fibrous caps being more susceptible to rupture and... (Review)
Review
Most acute cardiovascular events are due to plaque rupture, with atheromas containing large necrotic cores and thin fibrous caps being more susceptible to rupture and lesions with small necrotic cores and thick fibrous caps being more protected from rupture. Atherosclerotic plaques are comprised various extracellular matrix proteins, modified lipoprotein particles, and cells of different origins, that is, vascular cells and leukocytes. Although much has been revealed about the mechanisms that lead to plaque instability, several key areas remain incompletely understood. This In-Focus Review highlights processes related to cellular crosstalk and the role of the tissue microenvironment in determining cell function and plaque stability. Recent advances highlight critical underpinnings of atherosclerotic plaque vulnerability, particularly impairments in the ability of macrophages to clear dead cells and phenotypic switching of vascular smooth muscle cells. However, these processes do not occur in isolation, as crosstalk between macrophages and vascular smooth muscle cells and interactions with their surrounding microenvironment play a significant role in determining plaque stability. Understanding these aspects of cellular crosstalk within an atherosclerotic plaque may shed light on how to modify cell behavior and identify novel approaches to transform rupture-prone atheromas into stable lesions.
Topics: Humans; Leukocyte Count; Macrophages; Muscle, Smooth, Vascular; Myocytes, Smooth Muscle; Plaque, Atherosclerotic
PubMed: 35172605
DOI: 10.1161/ATVBAHA.121.316233 -
Antioxidants & Redox Signaling Jul 2021Since the discovery of vascular stem cells, there has been considerable advancement in comprehending the nature and functions of these cells. Due to their... (Review)
Review
Since the discovery of vascular stem cells, there has been considerable advancement in comprehending the nature and functions of these cells. Due to their differentiation potential to repair endothelial cells and to participate in lesion formation during vascular remodeling, it is crucial to elucidate vascular stem cell behaviors and the mechanisms underlying this process, which could provide new chances for the design of clinical therapeutic application of stem cells. Over the past decades, major progress has been made on progenitor/vascular stem cells in the field of cardiovascular research. Vascular stem cells are mostly latent in their niches and can be bioactivated in response to damage and get involved in endothelial repair and smooth muscle cell aggregation to generate neointima. Accumulating evidence has been shown recently, using genetic lineage tracing mouse models, to particularly provide solutions to the nature of vascular stem cells and to monitor both cell migration and the process of differentiation during physiological angiogenesis and in vascular diseases. This article reviews and summarizes the current research progress of vascular stem cells in this field and highlights future prospects for stem cell research in regenerative medicine. Despite recent advances and achievements of stem cells in cardiovascular research, the nature and cell fate of vascular stem cells remain elusive. Further comprehensive studies using new techniques including genetic cell lineage tracing and single-cell RNA sequencing are essential to fully illuminate the role of stem cells in vascular development and diseases. 35, 192-203.
Topics: Adipokines; Adipose Tissue; Animals; Biomarkers; Cell Differentiation; Cell Movement; Disease Susceptibility; Endothelial Cells; Gene Expression Regulation; Humans; Myocytes, Cardiac; Myocytes, Smooth Muscle; Neovascularization, Physiologic; Regeneration; Stem Cell Transplantation; Stem Cells; Vascular Remodeling; Wound Healing
PubMed: 33107320
DOI: 10.1089/ars.2020.8199 -
Tissue Engineering. Part C, Methods Apr 2021Neuromuscular junctions (NMJs), specialized synapses between motor neurons and muscle fibers, are essential for muscle activity. A simple and reproducible cell-based...
Neuromuscular junctions (NMJs), specialized synapses between motor neurons and muscle fibers, are essential for muscle activity. A simple and reproducible cell-based NMJ platform is needed to test the impact of chemicals on the neuron-muscle communication. Our platform utilizes genetically modified neurons and muscle cells, optimized culture conditions, and commercially available multielectrode array system for recording action potentials. Neuronal cells (NSC34) were optogenetically modified with channelrhodopsin chimera to allow for simultaneous, light-mediated, millisecond-precise activation of neuronal population. This signal is propagated through functional synapses to the muscle fibers. Muscle cells (C2C12) were modified by incorporating gap junction protein (Connexin-43) to improve intracellular communication without affecting muscle differentiation. This communication between muscle fibers resulted in better signal propagation and signal strength. Optimized culture medium facilitated the growth and differentiation of both cell types together. Our system was validated using vecuronium, a muscle relaxant, which abolished the muscle response. This model provides a unique tool for establishing a NMJ platform that is easy to record and analyze. Potential applications include nondestructive long-term screening of drugs affecting the NMJ.
Topics: Motor Neurons; Muscle Fibers, Skeletal; Neuromuscular Junction
PubMed: 33599165
DOI: 10.1089/ten.TEC.2020.0292 -
Current Topics in Membranes 2020Vascular smooth muscle cells (VSMC) are now considered important contributors to the pathophysiological and biophysical mechanisms underlying arterial stiffening in... (Review)
Review
Vascular smooth muscle cells (VSMC) are now considered important contributors to the pathophysiological and biophysical mechanisms underlying arterial stiffening in aging. Here, we review mechanisms whereby VSMC stiffening alters vascular function and contributes to the changes in vascular stiffening observed in aging and cardiovascular disease. Vascular stiffening in arterial aging was historically associated with changes in the extracellular matrix; however, new evidence suggests that endothelial and vascular smooth muscle cell stiffness also contribute to overall blood vessel stiffness. Furthermore, VSMC play an integral role in regulating matrix deposition and vessel wall contractility via interaction between the actomyosin contractile unit and adhesion structures that anchor the cell within the extracellular matrix. Aged-induce phenotypic modulation of VSMC from a contractile to a synthetic phenotype is associated with decreased cellular contractility and increased cell stiffness. Aged VSMC also display reduced mechanosensitivity and adaptation to mechanical signals from their microenvironment due to impaired intracellular signaling. Finally, evidence for decreased contractility in arteries from aged animals demonstrate that changes at the cellular level result in decreased functional properties at the tissue level.
Topics: Aging; Animals; Extracellular Matrix; Muscle, Smooth, Vascular; Myocytes, Smooth Muscle; Vascular Stiffness
PubMed: 33837694
DOI: 10.1016/bs.ctm.2020.08.008 -
Biochemical and Biophysical Research... Feb 2023The cell motility of smooth muscle cells (SMCs) is essential for vascular and internal organ development and tissue regeneration in response to damage. Cell migration...
The cell motility of smooth muscle cells (SMCs) is essential for vascular and internal organ development and tissue regeneration in response to damage. Cell migration requires dynamic changes in the actin-cytoskeleton via the p-21 activated kinase (Pak)-Cofilin signaling cascade, which is the central axis of the actin filaments. We previously identified that the Inka2 gene was preferentially expressed in the central nervous system (CNS) and revealed that Inka2 directly binds Pak4 to suppress its kinase activity, thereby regulating actin de-polymerization in dendritic spine formation of the forebrain neurons. However, its physiological significance outside the CNS remains unclear. Here we determined the Inka2 expression profile in various organs using in situ hybridization analysis and lacZ staining on Inka2 mice. Robust Inka2 expression was consistently detected in the SMCs of many peripheral organs, including the arteries, esophagus, stomach, intestine, and bladder. The scratch assay was used on primary cultured SMCs and revealed that Inka2 SMC exhibits accelerated cell migration ability without a change in the cell proliferation rate. Inka2 SMCs displayed Cofilin activation/phosphorylation, a downstream molecule of Pak4 signal cascade. These results suggest that Inka2 regulates SMC motility through modulating actin reorganization as the endogenous inhibitor of Pak4.
Topics: Animals; Mice; Actin Cytoskeleton; Actin Depolymerizing Factors; Actins; Cell Movement; Cells, Cultured; Myocytes, Smooth Muscle
PubMed: 36586159
DOI: 10.1016/j.bbrc.2022.12.068 -
Critical Reviews in Biomedical... 2022This paper presents a review of studies on the effects of local vibration training (LVT) on muscle strength along with the associated changes in neuromuscular and cell... (Review)
Review
This paper presents a review of studies on the effects of local vibration training (LVT) on muscle strength along with the associated changes in neuromuscular and cell dynamic responses. Application of local/direct vibration can significantly change the structural properties of muscle cell and can improve muscle strength. The improvement is largely dependent on vibration parameters such as amplitude and frequency. The results of 20 clinical studies reveal that electromyography (EMG) and maximal voluntary contraction (MVC) vary depending on vibration frequency, and studies using frequencies of 28-30 Hz reported greater increases in muscle activity in terms of EMG (rms) value and MVC data than the studies using higher frequencies. A greater muscle activity can be related to the recruitment of large motor units due to the application of local vibration. A greater increase in EMG (rms) values for biceps and triceps during extension than flexion under LVT suggests that types of muscles and their functions play an important role. Although a number of clinical trials and animal studies have demonstrated positive effects of vibration on muscle, an optimum training protocol has not been established. An attempt is made in this study to investigate the optimal LVT conditions on different muscles through review and analysis of published results in the literature pertaining to the changes in the neuromuscular activity. Directions for future research are discussed with regard to identifying optimal conditions for LVT and better understanding of the mechanisms associated with effects of vibration on muscles.
Topics: Electromyography; Muscle Cells; Muscle Contraction; Muscle Strength; Muscle, Skeletal; Vibration
PubMed: 35997107
DOI: 10.1615/CritRevBiomedEng.2022041625 -
Skeletal Muscle Dec 2021Measuring biological features of skeletal muscle cells is difficult because of their unique morphology and multinucleate nature upon differentiation. Here, we developed...
BACKGROUND
Measuring biological features of skeletal muscle cells is difficult because of their unique morphology and multinucleate nature upon differentiation. Here, we developed a new Fiji macro package called ViaFuse (that stands for viability and fusion) to measure skeletal muscle cell viability and differentiation. To test ViaFuse, we utilized immunofluorescence images of differentiated myotubes where the capping actin protein of muscle z-line subunit beta (CAPZB) was depleted in comparison with control cells.
RESULTS
We compared the values achieved using the ViaFuse macros first with manual quantification performed by researchers and second with those obtained utilizing the MATLAB muscle-centric software MyoCount. We observed a high degree of correlation between all methods of quantification.
CONCLUSIONS
ViaFuse can detect the borders of myotubes and identify nuclear clumps which have been limitations of previous muscle-centric imaging software. The ViaFuse macros require little computer power or space to run and user inputs to the ViaFuse macros are minimal, thereby automating the analysis process in a quick, easy, and accurate fashion. Additionally, the ViaFuse macros work with Fiji, an existing imaging software widely used by skeletal muscle researchers. Furthermore, ViaFuse is compatible with many computer systems, has a very intuitive interface, and does not require prior complex mathematical knowledge. Therefore, we propose ViaFuse as a robust and meticulous method to quantify skeletal muscle cell viability and differentiation.
Topics: Cell Differentiation; Cell Survival; Fiji; Muscle Fibers, Skeletal; Muscle, Skeletal
PubMed: 34915930
DOI: 10.1186/s13395-021-00284-3 -
Current Osteoporosis Reports Oct 2019Bone and muscle mass increase in response to mechanical loading and biochemical cues. Bone-forming osteoblasts differentiate into early osteocytes which ultimately... (Review)
Review
PURPOSE OF REVIEW
Bone and muscle mass increase in response to mechanical loading and biochemical cues. Bone-forming osteoblasts differentiate into early osteocytes which ultimately mature into late osteocytes encapsulated in stiff calcified matrix. Increased muscle mass originates from muscle stem cells (MuSCs) enclosed between their plasma membrane and basal lamina. Stem cell fate and function are strongly determined by physical and chemical properties of their microenvironment, i.e., the cell niche.
RECENT FINDINGS
The cellular niche is a three-dimensional structure consisting of extracellular matrix components, signaling molecules, and/or other cells. Via mechanical interaction with their niche, osteocytes and MuSCs are subjected to mechanical loads causing deformations of membrane, cytoskeleton, and/or nucleus, which elicit biochemical responses and secretion of signaling molecules into the niche. The latter may modulate metabolism, morphology, and mechanosensitivity of the secreting cells, or signal to neighboring cells and cells at a distance. Little is known about how mechanical loading of bone and muscle tissue affects osteocytes and MuSCs within their niches. This review provides an overview of physicochemical niche conditions of (early) osteocytes and MuSCs and how these are sensed and determine cell fate and function. Moreover, we discuss how state-of-the-art imaging techniques may enhance our understanding of these conditions and mechanisms.
Topics: Animals; Cell Differentiation; Extracellular Matrix; Humans; Mechanotransduction, Cellular; Muscle Cells; Osteocytes; Stress, Mechanical
PubMed: 31428977
DOI: 10.1007/s11914-019-00522-0 -
Comparative Biochemistry and... Mar 2021The capillary bed constitutes the obligatory pathway for almost all oxygen (O) and substrate molecules as they pass from blood to individual cells. As the largest organ,... (Review)
Review
The capillary bed constitutes the obligatory pathway for almost all oxygen (O) and substrate molecules as they pass from blood to individual cells. As the largest organ, by mass, skeletal muscle contains a prodigious surface area of capillaries that have a critical role in metabolic homeostasis and must support energetic requirements that increase as much as 100-fold from rest to maximal exercise. In 1919 Krogh's 3 papers, published in the Journal of Physiology, brilliantly conflated measurements of muscle capillary function at rest and during contractions with Agner K. Erlang's mathematical model of O diffusion. These papers single-handedly changed the perception of capillaries from passive vessels serving at the mercy of their upstream arterioles into actively contracting vessels that were recruited during exercise to elevate blood-myocyte O flux. Although seminal features of Krogh's model have not withstood the test of time and subsequent technological developments, Krogh is credited with helping found the field of muscle microcirculation and appreciating the role of the capillary bed and muscle O diffusing capacity in facilitating blood-myocyte O flux. Today, thanks in large part to Krogh, it is recognized that comprehending the role of the microcirculation, as it supports perfusive and diffusive O conductances, is fundamental to understanding skeletal muscle plasticity with exercise training and resolving the mechanistic bases by which major pathologies including heart failure and diabetes cripple exercise tolerance and cerebrovascular dysfunction predicates impaired executive function.
Topics: Animals; Capillaries; Diffusion; Humans; Muscle Cells; Muscles; Oxygen
PubMed: 33242636
DOI: 10.1016/j.cbpa.2020.110852