Fibroblast
Fibroblast | |
---|---|
Details | |
Location | Connective tissue |
Function | Extracellular matrix and collagen creation |
Identifiers | |
Latin | fibroblastus |
MeSH | D005347 |
TH | H2.00.03.0.01002 |
FMA | 63877 |
Anatomical terms of microanatomy |
A fibroblast is a type of biological cell that synthesizes the extracellular matrix and collagen,[1] produces the structural framework (stroma) for animal tissues, and plays a critical role in wound healing.[2] Fibroblasts are the most common cells of connective tissue in animals.
Structure
This section needs additional citations for verification. (April 2021) |
Fibroblasts have a branched
Unlike the
The life span of a fibroblast, as measured in chick embryos, is 57 ± 3 days.[3]
Relationship with fibrocytes
Fibroblasts and fibrocytes are two states of the same cells, the former being the activated state, the latter the less active state, concerned with maintenance and tissue metabolism. Currently, there is a tendency to call both forms fibroblasts. The suffix "-blast" is used in cellular biology to denote a stem cell or a cell in an activated state of metabolism.
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.[4] This remarkable behavior may lead to discomfort[clarification needed] in the rare event that they stagnate there excessively.
Development
The main function of fibroblasts is to maintain the structural integrity of connective tissues by continuously secreting precursors of the extracellular matrix (ECM), providing all such components, primarily the ground substance and a variety of fibers. The composition of the ECM determines the physical properties of connective tissues.
Like other cells of connective tissue, fibroblasts are derived from primitive
In certain situations, epithelial cells can give rise to fibroblasts, a process called
Conversely, fibroblasts in some situations may give rise to epithelia by undergoing a mesenchymal to epithelial transition and organizing into a condensed, polarized, laterally connected true epithelial sheet. This process is seen in many developmental situations (e.g.
Function
Fibroblasts make
Inflammation
Besides their commonly known role as structural components, fibroblasts play a critical role in an immune response to a tissue injury. They are early players in initiating inflammation in the presence of invading microorganisms. They induce chemokine synthesis through the presentation of receptors on their surface. Immune cells then respond and initiate a cascade of events to clear the invasive microorganisms. Receptors on the surface of fibroblasts also allow regulation of hematopoietic cells and provide a pathway for immune cells to regulate fibroblasts.[7]
Tumour mediation
Fibroblasts, like tumor-associated host fibroblasts (TAF), play a crucial role in immune regulation through TAF-derived ECM components and modulators. TAF are known to be significant in the inflammatory response as well as immune suppression in tumors. TAF-derived ECM components cause alterations in ECM composition and initiate the ECM remodeling.[8] ECM remodeling is described as changes in the ECM as a result of enzyme activity which can lead to degradation of the ECM. Immune regulation of tumors is largely determined by ECM remodeling because the ECM is responsible for regulating a variety of functions, such as proliferation, differentiation, and morphogenesis of vital organs.[9] In many tumor types, especially those related to the epithelial cells, ECM remodeling is common. Examples of TAF-derived ECM components include Tenascin and Thrombospondin-1 (TSP-1), which can be found in sites of chronic inflammation and carcinomas, respectively.[8]
Immune regulation of tumors can also occur through the TAF-derived modulators. Although these modulators may sound similar to the TAF-derived ECM components, they differ in the sense that they are responsible for the variation and turnover of the ECM. Cleaved ECM molecules can play a critical role in immune regulation. Proteases like matrix metalloproteineases (MMPs) and the uPA system are known to cleave the ECM. These proteases are derived from fibroblasts.[8]
Use of fibroblasts as feeder cells
In view of the potential clinical applications of stem cell-derived tissues or primary epithelial cells, the use of human fibroblasts as an alternative to MEF feeders has been studied.[13] Whereas the fibroblasts are usually used to maintain pluripotency of the stem cells, they can also be used to facilitate development of the stem cells into specific type of cells such as cardiomyocytes.[14]
Host immune response
Fibroblasts from different anatomical sites in the body express many genes that code for immune mediators and proteins.[15] These mediators of immune response enable the cellular communication with hematopoietic immune cells.[16] The immune activity of non-hematopoietic cells, such as fibroblasts, is referred to as “structural immunity”.[15][17] In order to facilitate a fast response to immunological challenges, fibroblasts encode crucial aspects of the structural cell immune response in the epigenome.[citation needed]
See also
References
- ^ "Fibroblast". Genetics Home Reference. U.S. National Library of Medicine. 2014-05-05. Retrieved 2014-05-10.
- ^ "Fibroblasts". Retrieved 16 August 2018.
- S2CID 9299977.
- ISBN 9781481682626.
- S2CID 26292524.
- PMID 26351669.
- PMID 9250144.
- ^ S2CID 10936034.
- PMID 25415508.
- PMID 25659081.
- PMID 29288165.
- PMID 29786564.
- PMID 25890180.
- PMID 30060947.
- ^ S2CID 220295181.
- PMID 33168968.
- S2CID 220491226.
External links
- UIUC Histology Subject 240
- MedEd at Loyola Histo/practical/ctproper/hp3-15.html