title: Nano-mechanical compliance of Müller cells investigated by atomic force microscopy.
abstract: It has been known that a single Müller cell displays a large variation in the cytoskeletal compositions along its cell body, suggesting different mechanical properties in different segments. Müller cells are thought to be involved in many retinal diseases such as retinoschisis, which can be facilitated by a mechanical stress. Thus, mapping of mechanical properties on localized nano-domains of Müller cells could provide essential information for understanding their structural functions in the retina and roles in their pathological progresses. Using Atomic Force Microscopy (AFM) - based bio-nano-mechanics, we have investigated the local variations of the mechanical properties of Müller cells in vitro. We have a particular interest in identifying elastic moduli in regions closer to three distinctive segments of the cells - process, endfoot, and soma. Using the modified spherical AFM probes, we were able to accurately determine mechanical properties, i.e., elastic moduli from the obtained force-distance curves. We found that the regions closer to soma were mechanically more compliant than regions closer to endfoot and process of Müller cells. We found that this lateral heterogeneity of the mechanical compliance within a single Müller cell is consistent with reports from other cell types. The local variation in mechanical compliances along a single Müller cell may support their diverse mechanical functions in the retina such as a soft mechanical embedding, mechanosensing, and neurotrophic functions for neurons.
authors.affiliation: Department of Physics, Texas Tech University, Box 41051, Lubbock, TX 79409, USA. sypark20@gmail.com
authors.forename: Soyeun
authors.initials: S
authors.lastname: Park
authors.forename: Yong J
authors.initials: YJ
authors.lastname: Lee
mesh_terms: D000818:Animals; D001696:Biomechanical Phenomena / Q000502:physiology*; D003187:Compliance; D055119:Elastic Modulus; D063928:Ependymoglial Cells / Q000502:physiology*; D005260:Female; D008297:Male; D018625:Microscopy, Atomic Force; D036103:Nanotechnology; D051381:Rats; D012160:Retina / Q000166:cytology
keywords: Atomic force microscopy; Young's modulus; glial cells; mechanical compliance.; nano-indentation
references.citation: Glia. 2001 May;34(3):190-9
references.pmid: 11329181
references.citation: Acta Biomater. 2007 Jul;3(4):413-38
references.pmid: 17540628
references.citation: ASN Neuro. 2012 May 01;4(4):201-5
references.pmid: 22455879
references.citation: Int J Biol Sci. 2011 Jan 20;7(1):102-11
references.pmid: 21278920
references.citation: Micron. 2007;38(8):824-33
references.pmid: 17709250
references.citation: Glia. 2013 May;61(5):651-78
references.pmid: 23440929
references.citation: Phys Rev Lett. 2000 Jul 24;85(4):880-3
references.pmid: 10991422
references.citation: Proc Natl Acad Sci U S A. 2006 Nov 21;103(47):17759-64
references.pmid: 17093050
references.citation: Ann Biomed Eng. 2009 May;37(5):847-59
references.pmid: 19259817
references.citation: J Neurosci. 2000 Aug 15;20(16):5965-72
references.pmid: 10934244
references.citation: Z Mikrosk Anat Forsch. 1988;102(5):721-55
references.pmid: 3239162
references.citation: Trends Neurosci. 1996 Aug;19(8):307-12
references.pmid: 8843598
references.citation: Biophys J. 2005 Dec;89(6):4330-42
references.pmid: 16199496
references.citation: Trends Cell Biol. 2004 Apr;14(4):160-6
references.pmid: 15066633
references.citation: Am J Ophthalmol. 2007 Mar;143(3):455-62
references.pmid: 17222382
references.citation: Z Mikrosk Anat Forsch. 1988;102(6):897-912
references.pmid: 3250146
references.citation: Biophys J. 2004 Mar;86(3):1777-93
references.pmid: 14990504
references.citation: Neuroreport. 2013 Mar 27;24(5):224-8
references.pmid: 23399998
references.citation: Invest Ophthalmol Vis Sci. 2001 Apr;42(5):1072-9
references.pmid: 11274088
references.citation: Arch Ophthalmol. 2004 Oct;122(10):1455-60
references.pmid: 15477456