Stem cell niche

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In biology, a stem cell niche is an environment within a multicellular organism that receives stem cells . The anatomical structure, cellular and non-cellular components are important components of the stem cell niche.

Adjacent, supporting cells, which present certain surface molecules to the stem cells (e.g. cadherins , catenins and integrins ) or release the signal molecules into the environment, can play a special role in the formation of the niche . Signals from the niche regulate self-renewal, survival and thus the maintenance of stem cells. The adhesion between stem cells and supporting stroma cells or the extracellular matrix anchors the stem cells in the stem cell niche and thus in the vicinity of the stem cell-preserving signals. The special spatial relationships of the stem cells with the supporting cells can lead to a polarization of the stem cell and thus to an asymmetrical cell division . In addition to a permanent stem cell, a precursor cell is created which divides more frequently and whose daughter cells further differentiate. The multiplication and / or differentiation of the stem cells can also be regulated by systemic factors.

Niches for different types of stem cells are very different from one another. Deregulation of the stem cell niche can be a cause of tissue degeneration, aging and tumor development.

The existence of a stem cell niche was first suggested by R. Schofield in 1978. It has now been detected in vertebrates and animal model organisms such as the fruit fly Drosophila melanogaster and the nematode Caenorhabditis elegans .

Examples

Incision of a femur head with substantia spongiosa (also substantia trabecularis). Between the small trabeculae is the red bone marrow, which also contains the niche for the blood stem cells. The white bar corresponds to 1 cm.

The niche for blood stem cells , from which, by blood cell formation , the blood cells emerge, is located in adult mammals marrow of some bones, more precisely in the cancellous bone of the bone ( "spongy" bone). The stem cells are closely associated with osteoblasts and endothelial cells of blood vessels. Neural stem cells are found in two different regions of the brain: the subventricular zone of the hippocampus and the olfactory bulb . In both niches, the stem cells are in close proximity to endothelial cells. Epithelial stem cells are located in a specialized region of the outer hair follicle sheath of the hair follicle .

Individual evidence

  1. ↑ a b c d e Jones DL, Wagers AJ: No place like home: anatomy and function of the stem cell niche . In: Nature reviews. Molecular cell biology . 9, No. 1, January 2008, pp. 11-21. doi : 10.1038 / nrm2319 . PMID 18097443 .
  2. ↑ Schofield R: The relationship between the spleen colony-forming cell and the haemopoietic stem cell . In: Blood cells . 4, No. 1-2, 1978, pp. 7-25. PMID 747780 .