OBJECTIVETo study the differences in expression of nuclear factor-kappaB (NF-kappaB) between human traumatic cataract and normal lenticular epithelial cells.

METHODSTotal RNA of anterior capsule specimens was taken under the microscope from normal cadaveric eyes donors and those suffering from traumatic cataract to make semi-quantitative RT-PCR and conduct analysis of differences in expression of NF-kappaB between them.

RESULTSAs compared with the mean of 0.8337 in normal control group, the expression equivalent of NF-kappaB was 0.9074 for the lenticular epithelial cells in traumatic cataract sufferers, and the differences are of noticeable significance (t = 2.447, P<0.05) accordingly.

CONCLUSIONSNF-kappaB is likely a kind of transcription factor necessary to maintain metabolism of normal lenticular epithelial cells. Higher NF-kappaB available in the traumatic cataract sufferer's lenticular epithelial cells means NF-kappaB is of possible relevance to occurrence and development of traumatic cataract.

Adolescent ; Adult ; Cataract ; genetics ; metabolism ; therapy ; Epithelial Cells ; metabolism ; Female ; Humans ; Lens, Crystalline ; injuries ; metabolism ; Male ; NF-kappa B ; genetics ; metabolism ; Polymerase Chain Reaction

Crystallins are the major proteins found in the lens, and the localization of specific crystallins is well known. Overexpression and accumulation of alphaB-crystallin has been observed in response to stress conditions or in certain diseases, such as brain tumors and neurodegenerative diseases. The purpose of this study was to examine whether alpha-crystallins are modified during pathological myofibroblastic changes in lens epithelial cells. Lens epithelial cells attached to the anterior capsules of patients with nuclear or anterior polar cataracts were analyzed quantitatively for alpha-crystallin proteins and mRNAs using Western blot and RT-PCR analysis., respectively. The degree of modification of alpha-crystallins was determined by 2-dimensional gel electrophoresis followed by Western blotting. Higher molecular weight protein bands that were immunoreactive to anti-alphaA- and anti-alphaB-crystallin antibodies around 45 kDa accumulated more in the anterior polar cataract samples than in those with the nuclear type of cataracts. Also monomeric alphaB-crystallins accumulated more in lens epithelial cells of patients with anterior polar cataracts. By comparison, no significant changes were found in the levels of the mRNAs encoding alphaA- and alphaB-crystallins in the different types of cataracts. Both alphaA- and alphaB-crystallin proteins seemed to undergo more extensive modification in anterior polar cataracts. Conclusion. In addition to fibrotic changes, which accompany increased levels of extracellular matrix molecules, accumulation and abnormal modification of alpha-crystallins might be implicated in the pathogenic mechanism of this type of cataract.
Adult ; Cataract/*genetics/metabolism ; Epithelial Cells/metabolism ; Female ; Human ; Lens, Crystalline/metabolism ; Male ; Middle Aged ; RNA, Messenger/analysis ; Reverse Transcriptase Polymerase Chain Reaction ; Support, Non-U.S. Gov't ; alpha-Crystallin A Chain/*genetics/metabolism ; alpha-Crystallin B Chain/*genetics/metabolism

β/γ-Crystallins are predominant structural proteins in the cytoplasm of lens fiber cells and share a similar fold composing of four Greek-key motifs divided into two domains. Numerous cataract-causing mutations have been identified in various β/γ-crystallins, but the mechanisms underlying cataract caused by most mutations remains uncharacterized. The S228P mutation in βB1-crystallin has been linked to autosomal dominant congenital nuclear cataract. Here we found that the S228P mutant was prone to aggregate and degrade in both of the human and E. coli cells. The intracellular S228P aggregates could be redissolved by lanosterol. The S228P mutation modified the refolding pathway of βB1-crystallin by affecting the formation of the dimeric intermediate but not the monomeric intermediate. Compared with native βB1-crystallin, the refolded S228P protein had less packed structures, unquenched Trp fluorophores and increased hydrophobic exposure. The refolded S228P protein was prone to aggregate at the physiological temperature and decreased the protective effect of βB1-crystallin on βA3-crystallin. Molecular dynamic simulation studies indicated that the mutation decreased the subunit binding energy and modified the distribution of surface electrostatic potentials. More importantly, the mutation separated two interacting loops in the C-terminal domain, which shielded the hydrophobic core from solvent in native βB1-crystallin. These two interacting loops are highly conserved in both of the N- and C-terminal domains of all β/γ-crystallins. We propose that these two interacting loops play an important role in the folding and structural stability of β/γ-crystallin domains by protecting the hydrophobic core from solvent access.
Amino Acid Substitution ; Cataract ; genetics ; metabolism ; HeLa Cells ; Humans ; Molecular Dynamics Simulation ; Mutation, Missense ; Protein Aggregation, Pathological ; genetics ; metabolism ; Protein Domains ; Protein Structure, Secondary ; Proteolysis ; beta-Crystallin B Chain ; chemistry ; genetics ; metabolism

Epalrestat is the unique aldose reductase inhibitor on the market, which was mainly used for the diabetic neuropathy. Lenses osmotic expansion could be induced by galactose to mimic the pathological process of diabetic cataract in vitro. In present study, we mainly investigated whether epalrestat possesses inhibitory effect on the lens osmotic expansion. The results indicated that epalrestat could not only markedly inhibit rat lens osmotic expansion in vitro, but also significantly reduced the high expression of the osmotic expansion-related genes such as AR and AQP1 in mRNA and protein levels. The findings may provide an important reference to epalrestat in the clinical application for the treatment of diabetic cataract.
Aldehyde Reductase ; antagonists & inhibitors ; biosynthesis ; genetics ; Animals ; Aquaporin 1 ; genetics ; metabolism ; Cataract ; etiology ; metabolism ; pathology ; Diabetes Mellitus, Experimental ; complications ; Enzyme Inhibitors ; pharmacology ; Galactose ; antagonists & inhibitors ; Lens, Crystalline ; drug effects ; metabolism ; pathology ; Male ; Osmosis ; drug effects ; RNA, Messenger ; metabolism ; Rats ; Rats, Sprague-Dawley ; Rhodanine ; analogs & derivatives ; pharmacology ; Thiazolidines ; pharmacology

BACKGROUNDCataracts is considered be formed because of an abnormal glucose metabolic pathway or oxidative stress. We explored the damaging role of ONOO- and antagonism of cholecystokinin octapeptide-8 (CCK-8) in diabetic cataractal rat lenses.

METHODSA diabetic cataractal animal model was established by peritoneal injection of streptozotocine (STZ). Thirty-six normal SD rats were taken as control group; seventy-two were given STZ (45 mg/kg) and then divided into STZ group and CCK-8 group (peritoneal injection CCK-8). STZ induced diabetic rats were treated with CCK-8 for 60 days. Lenses were examined with slit lamp at 20, 40 and 60 days. Immunofluorescent staining and Western blot analysis were used for determining nitrotyrosine (NT, a marker for ONOO-). PT-PCR and gene array analysis were used for determining the expression of inducible nitric oxide synthetase mRNA (iNOS mRNA) in lens epithelium (LEC).

RESULTSSTZ group rats developed lens opacity by 20 days that reached a high level by 60 days after STZ injection. CCK-8 group rats delayed the cataract formation. CCK-8 group rats delayed the cataract formation. There was no distinct expression of NT and iNOS mRNA in control group. In STZ group, there were distinct expression of NT and upregulation of iNOS mRNA; however, CCK-8 group showed weak expression of NT and downregulation of iNOS mRNA.

CONCLUSIONSNT, which may be a new form of oxidative stress, was expressed in diabetic rat LEC although CCK-8 could reverse NT damage in LEC. The results suggested that CCK-8 might be a useful therapeutic agent against diabetic cataract. The antagonizing mechanism of CCK-8 may be related to direct antagonism of ONOO- as well as its inhibition of the expression of iNOS mRNA for production of NO and therefore decrease in the formation of ONOO-.

Animals ; Blotting, Western ; Cataract ; etiology ; prevention & control ; Diabetes Mellitus, Experimental ; complications ; Fluorescent Antibody Technique ; Male ; Nitric Oxide Synthase Type II ; genetics ; Oxidation-Reduction ; Peroxynitrous Acid ; metabolism ; RNA, Messenger ; analysis ; Rats ; Rats, Sprague-Dawley ; Reverse Transcriptase Polymerase Chain Reaction ; Sincalide ; pharmacology ; Streptozocin ; Tyrosine ; analogs & derivatives ; genetics