Purchase this article with an account.
J.D. Rhodes, S. Russell, A.R. Prescott, G. Duncan; Defective Lens Calcium Dynamics in Myotonic Dystrophy . Invest. Ophthalmol. Vis. Sci. 2006;47(13):4108.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
Myotonic dystrophy (DM) cataractous lenses have a lower epithelial cell density than clear lenses. As the store operated calcium entry (SOC) pathway is believed to play a critical role in growth we have therefore investigated growth characteristics and calcium dynamics in lens cell lines derived from cataract patients with and without DM.
A total of 4 cell lines were derived by SV40 transformation of lens capsulorhexis specimens obtained immediately following cataract surgery. Rhexis samples were collected in culture medium and cells were infected with adenovirus carrying SV40 large T. Two age matched lines from routine cataracts (CCat1 and 2) and two from DM cataracts (DMCat1 and 2) were used in this study. Cells were counted at each passage using a haemocytometer. Cells grown on coverslips were preloaded with FURA2–am and intracellular calcium changes were monitored by ratio–metric fluorescent imaging at 340 and 380 nm wavelengths.
The mean population doubling times for CCat1 and 2 were 1.8 and 2.9 days respectively compared with 7.8 and 8.0 for DMCat1 and 2 respectively. The resting intracellular calcium levels were similar in both cell types. Rapid and reversible increases in intracellular calcium were observed in all cell lines when stimulated by a range of G–protein coupled agonists including ATP. The SOC pathway was investigated by reintroducing calcium to the external medium after emptying the calcium store by exposure to thapsigargin (1µM) or ATP (10 µM) under calcium free conditions. In all cell lines there was a rapid increase in cell calcium on re–admitting extra–cellular calcium, but the proportional increase in control cells was larger for both thapsigargin and ATP.
Immortalised lens cell lines derived from DM cataract patients exhibit markedly slower growth rates than those derived from non DM cataract patients. While the calcium dynamics of store release are similar in the 2 cell types the SOC pathway was impaired in the DM cells compared to the corresponding pathway in the controls. This difference may contribute to a slower growth rate in the DM cells.
This PDF is available to Subscribers Only