Alpha-smooth muscle actin (SMA), an actin isoform that contributes to cell-generated mechanical tension, is normally restricted to cells of vascular smooth muscle, but SMA can also be expressed in certain non-muscle cells, most notably myofibroblasts.
What is smooth muscle actin a marker of?
α-Smooth muscle actin (α-SMA) is used as a marker for a subset of activated fibrogenic cells, myofibroblasts, which are regarded as important effector cells of tissue fibrogenesis. … α-SMA is not a functional marker of fibrogenic cells in skeletal muscle fibrosis associated with muscular dystrophy.
What cells express alpha smooth muscle actin?
Myofibroblasts. Myofibroblasts express α-smooth muscle actin (α-SMA) and have contractile and secretory properties that are central to controlling tissue architecture [6]. They express a panel of markers that have been correlated with the site of origin.
What is muscle specific actin?
Muscle specific actin (MSA) is a highly conserved, ubiquitous protein found in muscle and some non-muscle cells. Actins can be divided into three subsets, alpha actins found in muscle tissue cells, beta and gamma actins found in non-muscle cells and a small subset of gamma actins also found in muscle tissue cells.
What does desmin positive mean?
If the cells in your sample produce desmin, your pathology report will describe the cells as positive or reactive. If they do not produce desmin, your report will describe the cells as negative or non-reactive.
How does smooth muscle contract?
Contraction. Smooth muscle contraction is caused by the sliding of myosin and actin filaments (a sliding filament mechanism) over each other. The energy for this to happen is provided by the hydrolysis of ATP. … Unlike cardiac and skeletal muscle, smooth muscle does not contain the calcium-binding protein troponin.
What does SMA stain for?
SMA: clone clone αsm-1. Human small bowel: immunohistochemical staining for Alpha Smooth Muscle Actin. Note cytoplasmic staining of the muscularis mucosa, vascular walls and smooth muscle fibers in the lamina propria.
What is smooth muscle made of?
Smooth muscle is a type of muscle that contracts without any voluntary control, and it is made of a thin form of layers, which is made up of spindle-shaped, unstriated cells with only one nucleus and present in inner organs walls like bladder, intestine, stomach, blood vessels, etc.
Do endothelial cells express smooth muscle actin?
Cardiac microvascular endothelial cells express α-smooth muscle actin and show low NOS III activity.
What cells express alpha SMA?
Myofibroblasts are conventionally identified by co-expression of collagen I and α-SMA [27–30], although α-SMA is also expressed by smooth muscle cells. α-SMA has been used not only as a differentiation marker but also as a functional marker for myofibroblasts [31–33].
What is the function of desmin?
Desmin is a myofibrillar protein that is the chief intermediate filament of skeletal and cardiac muscle [40]. It maintains the structural and functional integrity of the myofibrils and functions as a cytoskeletal protein linking Z bands to the plasma membrane.
What do myofibroblasts do?
Myofibroblasts are the mesenchymal cell type responsible for wound healing and tissue repair across all organs and various physiological states, including cancer [31].
Are histiocytes vimentin positive?
Lysozyme, vimentin, and CD68 were positive in all cases with histological information.
What does Calponin stain?
Immunohistochemistry. The spindle cells characteristically stain for vimentin, smooth muscle actin, muscle-specific actin, calponin, and caldesmon. Desmin and anaplastic lymphoma kinase 1 (ALK1) staining is observed in about half of the cases, and p80 expression is also frequent.
Is leiomyosarcoma desmin positive?
Leiomyosarcoma shows easily identifiable mitotic figures in addition to nuclear atypia and cellular pleomorphism. Leiomyosarcoma shows strong positive reaction in tumor cells for smooth muscle actin. Leiomyosarcoma shows strong positive reaction in tumor cells for desmin.
What is the meaning of desmin?
Desmin is a protein that in humans is encoded by the DES gene. … It is a 52kD protein that is a subunit of intermediate filaments in skeletal muscle tissue, smooth muscle tissue, and cardiac muscle tissue.
What is desmin cardiomyopathy?
Mutations in the desmin gene affecting intermediate filaments cause a distinct myopathy that is often associated with cardiomyopathy and is termed “desmin myopathy.” The mutant desmin interferes with the normal assembly of intermediate filaments, resulting in fragility of the myofibrils and severe dysfunction of …
Does smooth muscle have actin and myosin?
Smooth muscle cytoplasm contains large amounts of actin and myosin. Actin and myosin act as the main proteins involved in muscle contraction. Actin filaments attach to dense bodies spread throughout the cell. Dense bodies can be observed under an electron microscope and appear dark.
What is smooth muscle cell?
Smooth muscle cells (SMCs) are involuntary, non-striated muscle cells that line the insides of hollow organs such as arteries, lungs, bladder, the digestive system, and the reproductive system.
What initiates contraction in smooth muscle?
Smooth muscle contractions are initiated by an increase in intracellular Ca2+ concentration that can occur by intracellular release of Ca2+ from the sarcoplasmic reticulum or by influx of Ca2+ from the extracellular fluid.
What does Alpha SMA do?
ACTA2 (commonly referred to as alpha-smooth muscle actin or α-SMA) is often used as a marker of myofibroblast formation. Studies have shown that ACTA2 is associated with TGF β pathway that enhances contractile properties of Hepatic Stellate Cells leading to liver fibrosis and cirrhosis.
What is SMA tumor?
In normal human ovaries, alpha-SMA was found in the blood vessel walls, muscle fibers, and stromal cells surrounding the follicles. The main source of alpha-SMA in the benign ovarian tumors was the blood vessel walls which highly expressed the alpha-SMA throughout the tumor.
What type of cells does SMA stain?
It stains the muscularis propria and muscularis mucosae of the gastrointestinal tract, the uterine myometrium, medial layer of blood vessels, myoepithelial cells of salivary glands and other organs. The antibody does not stain skeletal and cardiac muscle, endothelium, connective tissue, epithelium or nerve.
How are smooth and actin myosin arranged?
Smooth muscle cells lack sarcomeres. Instead, actin filaments are arranged obliquely in the cytoplasm. Some filaments have their plus ends anchored at points in the plasma membrane termed dense plaques, whereas other filaments have plus ends anchored in dense bodies in the cytosol.
What are smooth muscles in the body?
Smooth muscle is found in the walls of hollow organs like your intestines and stomach. They work automatically without you being aware of them. Smooth muscles are involved in many ‘housekeeping’ functions of the body. The muscular walls of your intestines contract to push food through your body.
What makes smooth muscle unique?
Smooth muscles are unique in their largely involuntary response, and in their structure. Smooth muscles have a much stronger ability to contract than skeletal muscles, and are able to maintain contraction longer. … visceral smooth muscle – all cells work together at the same time as one unit.
What type of cells are smooth muscle cells?
Smooth muscle cells are spindle shaped, have a single, centrally located nucleus, and lack striations. They are called involuntary muscles. Cardiac muscle has branching fibers, one nucleus per cell, striations, and intercalated disks. Its contraction is not under voluntary control.
What are endothelial cells?
The endothelium is a thin membrane that lines the inside of the heart and blood vessels. Endothelial cells release substances that control vascular relaxation and contraction as well as enzymes that control blood clotting, immune function and platelet (a colorless substance in the blood) adhesion.
How do the endothelial cells regulate vascular smooth muscle contractility?
Endothelial cells secrete vasoactive agents and ROS that modulate the vessel diameter by influencing vascular smooth muscle cell function. The muscular media of vessels is innervated by the autonomic nervous system and its contractile state is regulated by hormones, vasoactive peptides, and ROS.
Graduated from ENSAT (national agronomic school of Toulouse) in plant sciences in 2018, I pursued a CIFRE doctorate under contract with Sun’Agri and INRAE in Avignon between 2019 and 2022. My thesis aimed to study dynamic agrivoltaic systems, in my case in arboriculture. I love to write and share science related Stuff Here on my Website. I am currently continuing at Sun’Agri as an R&D engineer.