title: Astrocytes in the optic nerve head express putative mechanosensitive channels.
abstract: OBJECTIVE
  To establish whether optic nerve head astrocytes express candidate molecules to sense tissue stretch.
  
  
  METHODS
  We used conventional PCR, quantitative PCR, and single-cell reverse transcription PCR (RT-PCR) to assess the expression of various members of the transient receptor potential (TRP) channel family and of the recently characterized mechanosensitive channels Piezo1 and 2 in optic nerve head tissue and in single, isolated astrocytes.
  
  
  RESULTS
  Most TRP subfamilies (TRPC, TRPM, TRPV, TRPA, and TRPP) and Piezo1 and 2 were expressed in the optic nerve head of the mouse. Quantitative real-time PCR analysis showed that TRPC1, TRPM7, TRPV2, TRPP2, and Piezo1 are the dominant isoforms in each subfamily. Single-cell RT-PCR revealed that many TRP isoforms, TRPC1-2, TRPC6, TRPV2, TRPV4, TRPM2, TRPM4, TRPM6-7, TRPP1-2, and Piezo1-2, are expressed in astrocytes of the optic nerve head, and that most astrocytes express TRPC1 and TRPP1-2. Comparisons of the TRPP and Piezo expression levels between different tissue regions showed that Piezo2 expression was higher in the optic nerve head and the optic nerve proper than in the brain and the corpus callosum. TRPP2 also showed higher expression in the optic nerve head.
  
  
  CONCLUSIONS
  Astrocytes in the optic nerve head express multiple putative mechanosensitive channels, in particular the recently identified channels Piezo1 and 2. The expression of putative mechanosensitive channels in these cells may contribute to their responsiveness to traumatic or glaucomatous injury.
authors.affiliation: Department of Ophthalmology, Harvard Medical School, Massachusetts Eye and Ear Infirmary, Boston, MA.
authors.forename: Hee Joo
authors.initials: HJ
authors.lastname: Choi
authors.affiliation: Department of Ophthalmology, Harvard Medical School, Massachusetts Eye and Ear Infirmary, Boston, MA.
authors.forename: Daniel
authors.initials: D
authors.lastname: Sun
authors.affiliation: Department of Ophthalmology, Harvard Medical School, Massachusetts Eye and Ear Infirmary, Boston, MA.
authors.forename: Tatjana C
authors.initials: TC
authors.lastname: Jakobs
mesh_terms: D000818:Animals; D001253:Astrocytes / Q000378:metabolism*; D004195:Disease Models, Animal; D005260:Female; D005901:Glaucoma / Q000209:etiology / Q000503:physiopathology; D007429:Intraocular Pressure / Q000502:physiology; D007473:Ion Channels / Q000235:genetics / Q000378:metabolism*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008811:Mice, Inbred DBA; D008822:Mice, Transgenic; D009898:Optic Disk / Q000166:cytology / Q000378:metabolism*; D020221:Optic Nerve Injuries / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D059010:Single-Cell Analysis; D050051:Transient Receptor Potential Channels / Q000235:genetics / Q000378:metabolism*
chemical_list: D007473:Ion Channels; C552920:Piezo1 protein, mouse; C552921:Piezo2 protein, mouse; D012333:RNA, Messenger; D050051:Transient Receptor Potential Channels