title: Extracellular matrix: a dynamic microenvironment for stem cell niche.
abstract: BACKGROUND
  Extracellular matrix (ECM) is a dynamic and complex environment characterized by biophysical, mechanical and biochemical properties specific for each tissue and able to regulate cell behavior. Stem cells have a key role in the maintenance and regeneration of tissues and they are located in a specific microenvironment, defined as niche.
  
  
  METHODS
  We overview the progresses that have been made in elucidating stem cell niches and discuss the mechanisms by which ECM affects stem cell behavior. We also summarize the current tools and experimental models for studying ECM-stem cell interactions.
  
  
  CONCLUSIONS
  ECM represents an essential player in stem cell niche, since it can directly or indirectly modulate the maintenance, proliferation, self-renewal and differentiation of stem cells. Several ECM molecules play regulatory functions for different types of stem cells, and based on its molecular composition the ECM can be deposited and finely tuned for providing the most appropriate niche for stem cells in the various tissues. Engineered biomaterials able to mimic the in vivo characteristics of stem cell niche provide suitable in vitro tools for dissecting the different roles exerted by the ECM and its molecular components on stem cell behavior.
  
  
  CONCLUSIONS
  ECM is a key component of stem cell niches and is involved in various aspects of stem cell behavior, thus having a major impact on tissue homeostasis and regeneration under physiological and pathological conditions. This article is part of a Special Issue entitled Matrix-mediated cell behaviour and properties.
authors.affiliation: Department of Molecular Medicine, University of Padova, 35131 Padova, Italy.
authors.forename: Francesca
authors.initials: F
authors.lastname: Gattazzo
authors.affiliation: Department of Molecular Medicine, University of Padova, 35131 Padova, Italy. Electronic address: annaurciolo@hotmail.com.
authors.forename: Anna
authors.initials: A
authors.lastname: Urciuolo
authors.affiliation: Department of Molecular Medicine, University of Padova, 35131 Padova, Italy. Electronic address: bonaldo@bio.unipd.it.
authors.forename: Paolo
authors.initials: P
authors.lastname: Bonaldo
mesh_terms: D000818:Animals; D055592:Biophysical Phenomena; D019070:Cell Lineage; D060833:Cellular Microenvironment; D005109:Extracellular Matrix / Q000378:metabolism*; D006801:Humans; D040542:Mechanotransduction, Cellular; D055153:Stem Cell Niche
keywords: Cell receptor; Extracellular matrix; Growth factor; Stem cell; Stem cell niche; Tissue engineering