Cross-linked actin networks (CLANs) are present in lamina cribrosa cells.
OBJECTIVE
A study was undertaken to determine and compare the F-actin staining patterns in the cells of the lamina cribrosa (LC) of normal, dexamethasone (DEX)-treated and glaucomatous dissected tissue and cell cultures.


METHODS
About 30 dissected donor eyes and nine cell lines provided the human specimens; 25 eyes and 20 primary cell cultures provided the bovine material. Appropriate samples were exposed to 1×10⁻⁷ M DEX for up to 14 days. LC tissue and cells were stained with Phalloidin-Alexa 488 to identify F-actin, and all samples were examined by confocal or epifluorescent microscopy.


RESULTS
Both in the LC tissue and LC cell cultures the dominant actin arrangement was bundles of stress fibres. However, cross-linked actin networks (CLANs) were identified in the tissue and in culture. These were markedly increased by steroid treatment and were particularly large and abundant in cultures from glaucoma donors. CLANs were not associated with optic nerve head astrocytes.


CONCLUSIONS
The presence of abundant stress fibres in situ and in vitro highlights the biomechanical contribution of LC cells. However, the identification of CLANs in these cells shows that they are not exclusive to the trabecular meshwork, the only other place they have been found, and may have a role in glaucoma pathology.
Job
Raly
R
Eye Care Centre, Leighton Hospital, Crewe, Cheshire, UK. ralyjob@gmail.com
Raja
Vignesh
V
Grierson
Ian
I
Currie
Laura
L
O'Reilly
Steven
S
Pollock
Natalie
N
Knight
Emma
E
Clark
Abbot F
AF
D000199:Actins / Q000378:metabolism*; D000368:Aged; D000369:Aged, 80 and over; D000818:Animals; D000959:Antihypertensive Agents / Q000494:pharmacology*; D002417:Cattle; D002478:Cells, Cultured; D003432:Cross-Linking Reagents / Q000378:metabolism; D003907:Dexamethasone / Q000494:pharmacology*; D005902:Glaucoma, Open-Angle / Q000188:drug therapy / Q000378:metabolism*; D006801:Humans; D018613:Microscopy, Confocal; D008875:Middle Aged; D009412:Nerve Fibers / Q000378:metabolism*; D009900:Optic Nerve / Q000378:metabolism*
D000199:Actins; D000959:Antihypertensive Agents; D003432:Cross-Linking Reagents; D003907:Dexamethasone