title: Myofibroblasts.
abstract: OBJECTIVE
  Interest in the myofibroblast as a key player in propagation of chronic progressive fibrosis continues to elicit many publications, with focus on its cellular origins and the mechanisms underpinning their differentiation and/or transition. The objective of the review is to highlight this recent progress.
  
  
  RESULTS
  The epithelial origin of the myofibroblast in fibrosis has been challenged by recent studies, with the pericyte suggested as a possible precursor instead. Additional signaling pathways, including Notch, Wnt, and hedgehog, are implicated in myofibroblast differentiation. The importance of NADPH oxidase 4 was highlighted recently to suggest a potential link between cellular/oxidative stress and the genesis of the myofibroblast. Recent observations on the importance of lysophosphatidic acid in fibrosis suggest that this may be due, in part, to its ability to regulate myofibroblast differentiation. Finally, there is increasing evidence for the role of epigenetic mechanisms in regulating myofibroblast differentiation, including DNA methylation and miRNA regulation of gene expression.
  
  
  CONCLUSIONS
  These recent discoveries open up a whole new array of potential targets for novel antifibrotic therapies. This is of special importance given the current bleak outlook for chronic progressive fibrotic diseases, such as scleroderma, due to lack of effective therapies.
authors.affiliation: Department of Pathology, University of Michigan Medical School, Ann Arbor, Michigan 48109-2200, USA.
authors.forename: Biao
authors.initials: B
authors.lastname: Hu
authors.forename: Sem H
authors.initials: SH
authors.lastname: Phan
mesh_terms: D002454:Cell Differentiation / Q000502:physiology; D044127:Epigenesis, Genetic / Q000502:physiology; D058750:Epithelial-Mesenchymal Transition / Q000502:physiology; D005355:Fibrosis; D006801:Humans; D058628:Myofibroblasts / Q000166:cytology*; D015398:Signal Transduction / Q000502:physiology