contractile cell myofibroblast cell Myofibroblasts are specialized cells predominantly found within the connective tissues of the body, most notably in areas of injury or wound healing. They carry out a crucial role in many biological processes, including tissue repair and fibrosis, wound contraction, and organogenesis. Though similar to fibroblasts, myofibroblasts can be differentiated by their unique morphological features and the presence of specialized protein bundles called stress fibers. Myofibroblasts originate from several cell types based on the physiological condition or the injury context, including local fibroblasts, epithelial cells, and endothelial cells, shedding light onto their plasticity. Upon tissue injury or wound creation, myofibroblasts activate and undergo a transformation process whereby they develop contractile features. They express a type of protein called alpha-smooth muscle actin (α-SMA), allowing them to contract and aid in wound closure. These cells also produce extracellular matrix (ECM) components, primarily collagen, to support and provide structural integrity to the healing tissue. However, while myofibroblasts play a critical role in normal wound healing, their function can be detrimental in certain pathological conditions. For instance, in chronic diseases such as fibrosis or scarring, the extended presence or overactivity of myofibroblasts can lead to the excessive production of ECM and fibrous tissues, leading to hardened, rigid tissues and organ dysfunction. (This extended description was generated by ChatGPT and reviewed by the CellGuide team, who added references, and by the CL editors, who approved it for inclusion in CL. It may contain information that applies only to some subtypes and species, and so should not be considered definitional.) An animal cell that has characteristics of both a fibroblast cell and a smooth muscle cell. MFB https://cellxgene.cziscience.com/cellguide/CL_0000186 Myofibroblasts are alpha-SMA-positive, CD34-negative, CD45-negative. They are reportedly capable of secreting IL-1beta, IL-6, and TNF-alpha. connective tissue cell Homo sapiens