NIH/3T3 Fibroblasts

A fibroblast is a type of cell that synthesizes and maintains the extracellular matrix of many animal tissues. Fibroblasts provide a structural framework (stroma) for many tissues, and play a critical role in wound healing. They are the most common cells of connective tissue in animals. Image File history File links Metadata Size of this preview: 800 × 600 pixelsFull resolution (2816 × 2112 pixel, file size: 993 KB, MIME type: image/jpeg) Image taken with Canon Powershot S3 on Nikon TS100 inverted microscope by the author using phase contrast microscopy. ... Image File history File links Metadata Size of this preview: 800 × 600 pixelsFull resolution (2816 × 2112 pixel, file size: 993 KB, MIME type: image/jpeg) Image taken with Canon Powershot S3 on Nikon TS100 inverted microscope by the author using phase contrast microscopy. ... Drawing of the structure of cork as it appeared under the microscope to Robert Hooke from Micrographia which is the origin of the word cell being used to describe the smallest unit of a living organism Cells in culture, stained for keratin (red) and DNA (green) The cell is the... Illustration depicting extracellular matrix (basement membrane and interstitial matrix) in relation to epithelium, endothelium and connective tissue In biology, the extracellular matrix (ECM) is the extracellular part of animal tissue that usually provides structural support to the cells in addition to performing various other important functions. ... For other uses, see Animal (disambiguation). ... Stroma can refer to: The connective supportive framework of a biological cell, tissue, or organ. ... Wound healing, or wound repair, is the bodys natural process of regenerating dermal and epidermal tissue. ... Connective tissue is one of the four types of tissue in traditional classifications (the others being epithelial, muscle, and nervous tissue. ...

The main function of fibroblasts is to maintain the structural integrity of connective tissue by continuously secreting precursors of the extracellular matrix. Fibroblasts secrete the precursors of all the components of the extracellular matrix, primarily the ground substance and a variety of fibres. The composition of the extracellular matrix determines the physical properties of connective tissues. Chemical structure of one unit in a chondroitin sulfate chain. ... For the meaning of fiber in nutrition, see dietary fiber. ...

Fibroblasts are morphologically heterogeneous with diverse appearances depending on their location and activity. Though morphologically inconspicuous, ectopically transplanted fibroblasts can often retain positional memory of the location and tissue context where they had previously resided, at least over a few generations. Ectopia is a displacement or malposition of an organ of the body. ...

Unlike the epithelial cells lining the body structures, fibroblasts do not form flat monolayers and are not restricted by a polarizing attachment to a basal lamina on one side, although they may contribute to basal lamina components in some situations (eg subepithelial myofibroblasts in intestine may secrete the α-2 chain carrying component of the laminin which is absent only in regions of follicle associated epithelia which lack the myofibroblast lining). Fibroblasts can also migrate slowly over substratum as individual cells, again in contrast to epithelial cells. While epithelial cells form the lining of body structures, it is fibroblasts and related connective tissues which sculpt the "bulk" of an organism. In zootomy, epithelium is a tissue composed of a layer of cells. ... The basal lamina (often erroneously called basement membrane) is a layer on which epithelium sits. ... Histological section through testicular parenchyma of a boar. ... In anatomy, the intestine is the segment of the alimentary canal extending from the stomach to the anus and, in humans and other mammals, consists of two segments, the small intestine and the large intestine. ... Laminins are the major non-collagenous component of the basal lamina, such as those on which cells of an epithelium sit. ...

Embryologic Origin

Like other cells of connective tissue, fibroblasts are derived from primitive mesenchyme. Thus they express the intermediate filament protein vimentin, a feature used as a marker to distinguish their mesodermal origin. However, this test is not specific as epithelial cells cultured in vitro on adherent substratum may also express vimentin after some time. Mesenchyme (also known as embryonic connective tissue) is the mass of tissue that develops mainly from the mesoderm (the middle layer of the trilaminar germ disc) of an embryo. ... Introduction Vimentin is part of the intermediate filament family. ...

In certain situations epithelial cells can give rise to fibroblasts, a process called epithelial-mesenchymal transition (EMT). Epithelial-mesenchymal transition (EMT) is a program of development of biological cells characterized by loss of cell adhesion, repression of E-cadherin expression, and increased cell mobility. ...

Conversely, fibroblasts in some situations may give rise to epithelia by undergoing a mesenchymal to epithelial transition (MET) and organizing into a condensed, polarized, laterally connected true epithelial sheet. This process is seen in many developmental situation (eg. nephron and notocord development) A nephron is the basic structural and functional unit of the kidney. ... The notochord is a flexible, rod-shaped body found in embryos of all chordates. ...

Structure and Function

Fibroblasts have a branched cytoplasm surrounding as an elliptical, speckled nucleus having 1 or 2 nucleoli. Active fibroblasts can be recognized by their abundant rough endoplasmic reticulum. Inactive fibroblasts, which are also called fibrocytes, are smaller and spindle shaped. They have a reduced rough endoplasmic reticulum. Although disjointed and scattered when they have to cover a large space, fibroblasts when crowded often locally align parallelly in clusters. Organelles. ... HeLa cells stained for DNA with the Blue Hoechst dye. ... In biology, the nucleolus is, strictly speaking, a suborganelle of the cell nucleus, which is an organelle. ... The endoplasmic reticulum or ER is an organelle found in all eukaryotic cells that is an interconnected network of tubules, vesicles and cisternae that is responsible for several specialized functions: Protein translation, folding, and transport of proteins to be used in the cell membrane (e. ...

Fibroblasts make collagens, glycosaminoglycans, reticular and elastic fibers, and glycoproteins found in the extracellular matrix. Growing individuals' fibroblasts are dividing and synthesizing ground substance. Tissue damage stimulates fibrocytes and induces the mitosis of fibroblasts. Tropocollagen triple helix. ... Chondroitin sulfate Hyaluronan Glycosaminoglycans (GAGs) or mucopolysaccharides are long unbranched polysaccharides consisting of a repeating disaccharide unit. ... Reticular fibers are the structural fiber in some connective tissues. ... Elastic fibers are bundles of proteins (elastin) found in connective tissue and produced by fibroblasts and smooth muscle cells in arteries. ... A glycoprotein is a macromolecule composed of a protein and a carbohydrate (an oligosaccharide). ... Illustration depicting extracellular matrix (basement membrane and interstitial matrix) in relation to epithelium, endothelium and connective tissue In biology, the extracellular matrix (ECM) is the extracellular part of animal tissue that usually provides structural support to the cells in addition to performing various other important functions. ... Mitosis divides genetic information during cell division. ...

"Fibroblast-like cells proliferate, migrate, synthesize ECM macromolecules, secrete growth factors, and form cell projections of different morphologies that explore their environment and generate mechanical forces. None of these activities is unique to these cells: epithelial cells can engage in all of these behaviors. However, the difference between these two types of cells is a difference in scale. Fibroblast-like cells are “professionals” in movement, ECM production, and deposition, and in a multitude of filopodial activities that enable them to shape the ECM and pull other cells. All this they perform in a grand manner. Other cell types perform specific tasks (hormone production, contraction, production of electrical signals, etc.), and their morphology reflects their specific function. Fibroblast-like cells, in contrast, exhibit similar morphologies, even when they perform different behavioral activities in different tissues." -from The Sculpturing Role of Fibroblast-Like Cells in Morphogenesis By Fanny Doljanski, in Perspectives in Biology and Medicine - Volume 47, Number 3, Summer 2004, pp. 339-356

Secondary actions

Mouse embryonic fibroblasts (MEFs) are often used as "feeder cells" in human embryonic stem cell research. However, many researchers are gradually phasing out MEF's in favor of culture media with precisely defined ingredients of exclusively human derivation. Further, the difficulty of exclusively using human derivation for media supplements is most often solved by the use of "defined media" where the supplements are synthetic and achieve the primary goal of eliminating the chance of contamination from derivative sources. Mouse embryonic stem cells with fluorescent marker. ...

See also

• fibrocartilage callus
• Fibrous connective tissue
• 3T3 cells

A fibrocartilage callus is a temporary fibrocartilage callus which forms as bone attemps to heal a fracture. ... ... 3T3 cells come from a cell line established in 1962 by two scientists then at the Department of Pathology in the New York University School of Medicine, George Todaro and Howard Green. ...

External links

• fibroblast at eMedicine Dictionary
• UIUC Histology Subject 240
• MedEd at Loyola Histo/practical/ctproper/hp3-15.html