ABSTRACT. The objectives of this study were to investigate the distributions of abnormally expressed optineurin (OPTN) proteins in retinal ganglion cells (RGC5s) of transgenic rats and their effects on subcellular morphological structures. Green fluorescent protein labeled EGFP wildtype (OPTN WT ), E50K mutant type (OPTN E50K ), and OPTN siRNA (si-OPTN) eukaryotic expression plasmids were constructed and transfected into RGC5s. Intracellular structures were labeled with organelle specific fluorescent dyes. Construct localization and cell morphologies were visualized by confocal fluorescence microscopy. OPTN WT was observed to be distributed as fine punctate fluorescent particles in the cytoplasm around the nucleus, along with exhibiting nuclear expression. OPTN E50K exhibited similar distribution but with non-uniform fluorescence particle size. si-OPTN distribution was similar to that of EGFP: uniform across the cytoplasm and nucleus. Compared with the negative control group, OPTN WT , and OPTN E50K and to a lesser degree pEGFP-transfected cells exhibited fracture and loss of myofilament proteins and mitochondrial swelling and cytoplasmic accumulation, along with abnormal lysosomal distribution and increased volume, and Golgi fragmentation. However, si-OPTN transfected cells exhibited no significant damage. Therefore, we demonstrated that the E50K mutation disrupts the uniformity of OPTN protein distribution upon exogenous overexpression. Furthermore, these results suggested that si-OPTN transfection, and thus potentially OPTN knockdown, did not impact subcellular morphology of RGC5 cells, whereas transfection, especially when combined with wild-type or mutant OPTN expression, led to substantial abnormalities in subcellular morphological structures. These findings lay a foundation for further research into the function of the OPTN protein.
This study aimed to modify the mixed and purified culture of rat retinal ganglion cells (RGCs) in vitro. The retinae of 1-3 day old Sprague-Dawley (SD) rats were separated bluntly into two layers: inner layer and outer layer, under a surgical microscope. Retinal cells isolated from different layers (inner layer, outer layer and whole retinal tissue) by using enzyme dissociation method were cultured in F12/DMEM medium containing 15% FBS. After 3-day culture, the RGCs in the retinal cells obtained from mixed culture of inner, outer, and whole retinal tissue were identified by immunocytochemical staining of Thy-1.1, and the rate of RGCs to retinal cells (RGCs%) was calculated. Two monoclonal antibodies, anti-macrophages/granulocytes (OX-41) against rat macrophage and antibody against rat Thy-1.1 (OX-7), were used to purify RGCs by either a conventional or modified two-stepped immunopanning procedure (purification in situ). Purified RGCs were seeded at different cell density and cultured in F12/DMEM medium containing 15% FBS. Immunocytochemical staining for Thy-1.1, MTT, and PI-Hoechst33342 fluorescence imaging were used to identify the purity and the viability of RGCs in purified culture of RGCs. The results showed: (1) Immunocytochemistry of different retinal tissue layers culture revealed that the RGCs% was (19.9 ± 1.2)%, (0.5 ± 0.2)%, and (6.2 ± 1.7)% respectively in the mixed culture of inner, outer, and whole retinal tissue, with differences being significant (P<0.05); (2) fluorescent double staining of Hoechst33342 and PI indicated that with the same RGCs%, RGCs obtained from purification in situ grew well with more neurite outgrowth than those by the conventional two-stepped immunopanning method; (3) the viability of purified RGCs seeded at high density was increased and the cells developed complex intercellular networks. The viability of RGCs was declined with the decreasing seeding density, and most cells presented round or oval in shape with thin neurites. It was concluded that: (1) RGCs% in the inner layer retina was higher than that in the outer layer retina; (2) RGCs obtained by in situ purification had more neurite outgrowth and lower mortality than those by conventional two-stepped immunopanning procedure; (3) the viability of purified RGCs could be increased by increasing cell seeding density to some extent.
The effects of lutein on the growth and migration of bovine lens epithelial cells (BLECs) in vitro were observed in an attempt to find a drug that can prevent after-cataract. BLECs were cultured in vitro and different concentrations of lutein were added to the BLECs cultures of the second and third generations. The effects of lutein on the proliferation of BLECs in vitro were examined by the MTT method, and the migration of BLECs was evaluated by a scratch wound assay. The results showed that: (1) Lutein at concentrations of 1 to 16 micromol/L could inhibit the proliferation of BLECs in a dose-and time-dependent manner (P<0.01): (2) The migration of BLECs was evaluated by wound healing rate. As compared with the control group, the wound healing rate in the experimental groups was decreased from 0.672+/-0.164 to -0.234+/-0.144 and -0.597+/-0.063 (P<0.01) at 1 and 2 micromol/L lutein, respectively. It was concluded that lutein at concentration of >or=1 micromol/L inhibited the proliferation and migration of BLECs in vitro. Lutein may become an effective drug to prevent after-cataract.
To investigate the effect of proteasome inhibitor MG132 on the apoptosis of bovine lens epithelial cells (BLECs), the cells were treated with MG132 at different concentrations for 12, 24 and 36 h. The cell viability was analyzed by MTT assay and the effect of MG132 on the apoptosis of BLECs was assessed by flow cytometry (FCM). The results showed that after treatment for the same period, the inhibitory effect of MG132 on BLECs proliferation was enhanced with the increment of the concentration of MG132 (0, 2, 5, 10, mumol/L) (P<0.05). The 50% inhibiting concentration (IC(50)) was 2.03 mumol/L when the BLECs were treated with MG132 for 36 h. MG132 also induced the apoptosis of BLECs obviously. FCM showed that the apoptosis index of the cells treated by MG132 at 2 mumol/L for 12 h was (20.24+/-1.51)%, and that of the control was (0.98+/-0.20)% respectively (P<0.01, n=3). It was concluded that MG132 could lead to apoptosis of BLECs. The decrease of proteasome activity may play an important role in the formation and development of cataract.
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