Do myofibroblasts proliferate?
Myofibroblasts are resident cells of wound healing, contractures and fibroses; these tissues are often referred to as fibroproliferative. Whether myofibroblasts themselves proliferate is of interest. Since many in vitro cultures are heterogeneous, staining in situ is required to identify the myofibroblast.
What does alpha-smooth muscle actin?
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.
Which cells express alpha-smooth muscle actin?
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 are Myofibroblastic cells?
Myofibroblasts are a differentiated cell type essential for wound healing, participating in tissue remodeling following insult. Myofibroblasts are typically activated fibroblasts, although they can also be derived from other cell types, including epithelial cells, endothelial cells, and mononuclear cells.
Do myofibroblasts produce collagen?
Instead, TGF-β1 stimulates the differentiation of fibroblasts to myofibroblasts. This differentiation is apparently irreversible, and rat cardiac myofibroblasts have probably a stable phenotype. Myofibroblasts produce collagen with a higher activity than their progeny, fibroblasts.
What do myofibroblasts secrete?
*Collagen types I, III, IV, and VI are secreted by myofibroblasts; type IV is the basement membrane collagen. † Perlecan is a proteogly- can secreted by epithelial cells.
Where is alpha smooth muscle actin found?
Alpha-smooth muscle actin, a differentiation marker of smooth muscle cells, is present in microfilamentous bundles of pericytes. J Histochem Cytochem.
How do smooth muscles contract?
Smooth muscle cells also develop tonic and phasic contractions in response to changes in load or length. Regardless of the stimulus, smooth muscle cells use cross-bridge cycling between actin and myosin to develop force, and calcium ions (Ca2+) serve to initiate contraction.
Which hormone is responsible for the contraction of smooth muscles?
Smooth muscles are stimulated to contract by catecholamines released by nerves in the vicinity of the muscle, as well as by a number of other hormones. Smooth muscles are also stimulated by the catecholamines in the bloodstream that originate in the secretions of the adrenal medulla.
How do myofibroblasts contract?
Myofibroblasts can contract by using smooth muscle type actin-myosin complex, rich in a form of actin called alpha-smooth muscle actin. These cells are then capable of speeding wound repair by contracting the edges of the wound.
How are myofibroblasts activated?
A classical view is that myofibroblasts derive from fibroblasts for wound repair, where they produce and contract granulation tissue to fill and close a lesion. Recent studies have revealed that myofibroblasts derive from a wide variety of cell types [7, 8], maybe triggered by signaling cues beyond injury .
Does myofibroblasts secrete collagen?
Myofibroblasts produce collagen with a higher activity than their progeny, fibroblasts. The higher activity of collagen production in rat cardiac myofibroblasts compared with fibroblasts is apparently an intrinsic property of the myofibroblasts and cannot be regulated by TGF-β1.