Proteomic analysis of aqueous humor from cataract patients with retinitis pigmentosa.

A postcataract surgery complication in patients with retinitis pigmentosa (RP) is lens capsular contraction. To identify potential proteins contributing to this phenomenon, high-performance liquid chromatography/mass spectrometry-based proteomic analysis was conducted with aqueous humor samples collected from 11 patients who underwent cataract surgeries, with four patients diagnosed as RP and cataract (RP group) and the other seven with only senile cataract group. The upregulated proteins in the RP group were enriched in wound response, while downregulated proteins were enriched in cell adhesion and lens crystallins. Receptors of two dramatically upregulated proteins tenascin-C (TNC) and serotransferrin were found expressed in human lens epithelial cells (HLEs). TNC can promote primary HLEs proliferation and cell line HLE-B3 migration. This study indicates aqueous humor proteomic analysis serves as an effective way to unveil the pathogenesis of RP complications. TNC is a potential target of stimulating HLEs proliferation in RP concomitant cataract patients that worth further research.

Ultrastructural and immunofluorescence analysis of anterior lens capsules in autosomal recessive Alport syndrome.

Background: To first report and study the ultrastructural and immunofluorescence abnormalities of the lens anterior capsules in a patient with autosomal recessive Alport syndrome.Methods: Two anterior lens capsules were collected in femtosecond laser-assisted cataract surgeries from a 29-year-old male patient with bilateral lenticonus caused by autosomal recessive Alport syndrome. The left capsule was examined by transmission electron microscopy and the right capsule was serial sectioned and stained with antibodies against the α2, α3, and α4 chains of type Ⅳ collagen. Anterior lens capsules of another two uncomplicated age-related cataract patients were collected and treated in the same way as the control.Results: The novel findings are that the mitochondria in lens epithelial cells in autosomal recessive Alport syndrome patients increased, twisted, and exhibited high electron density. Characteristic ultrastructure changes of capsule thinning, vertical dehiscence, and irregular-shaped lens epithelial cells were also observed in the left anterior lens capsule. Normal reactivity against the α2 chain and decreased reactivity against the α3 and α4 chains were observed in the right anterior lens capsule.Conclusions: The homozygous c.4599 T > G mutation of COL4A4 not only affects the formation of type Ⅳ collagen networks in the extracellular matrix, but also affects the morphology and survival of the lens epithelial cells in the patient with autosomal recessive Alport syndrome. This study is the first report of the ultrastructural and immunofluorescence changes of anterior lens capsules in autosomal recessive Alport syndrome.

Effects of Orally Consumed Rosa damascena Mill. Hydrosol on Hematology, Clinical Chemistry, Lens Enzymatic Activity, and Lens Pathology in Streptozotocin-Induced Diabetic Rats.

Diabetes mellitus is a multisystemic metabolic disorder that may affect the eyes, kidneys, vessels, and heart. Chronic hyperglycemia causes non-enzymatic glycation of proteins and elevation of the polyol pathway resulting in oxidative stress that damages organs. The current study aimed to investigate the dose-dependent effects of orally consumed Rosa damascena Mill. hydrosol on hematology, clinical biochemistry, lens enzymatic activity, and lens pathology in streptozotocin (STZ)-induced diabetic rats. Diabetes was induced into male Sprague-Dawley rats by intraperitoneal administration of STZ (40 mg/kg body weight). Rose hydrosols containing 1515 mg/L and 500 mg/L total volatiles (expressed as citronellol) were introduced to rats orally for 45 days. Consumption of 1515 mg/L volatile containing rose hydrosol successfully ameliorated hematologic, hepatic, and renal functions. Hydrosols also attenuated hyperglycemia and decreased the advanced glycation end-product formation in a dose-dependent manner. Rose hydrosol components significantly increased the lens enzymatic activities of glutathione peroxidase and decreased the activity of aldose reductase to prevent cataractogenesis. Histopathological examinations of rat lenses also indicated that increasing the dose of rose hydrosol had a protective effect on lenses in diabetic conditions. Additionally, in silico modeling of aldose reductase inhibition with rose hydrosol volatiles was carried out for extrapolating the current study to humans. The present results suggest that rose hydrosol exerts significant protective properties in diabetes mellitus and has no toxic effect on all studied systems in healthy test groups.

The effects of c-Src kinase on EMT signaling pathway in human lens epithelial cells associated with lens diseases.

BACKGROUND: The signaling pathway of epithelial to mesenchymal transition (EMT) is regulated by c-Src kinase in many cells. The purpose of this study was to investigate the effects of c-Src kinase on EMT of human lens epithelial cells in vivo stimulated by different factors. METHODS: Human lens epithelial cells, HLE-B3, were exposed to either an inflammatory factor, specifically IL-1α, IL-6, TNF-α or IL-1ß, at 10 ng/mL or high glucose (35.5 mM) for 30 mins. Activity of c-Src kinase was evaluated by the expression of p-Src418 with western blot assay. To investigate the effects of activation of c-Src on EMT, HLE-B3 cells were transfected with pCDNA3.1-SrcY530F to upregulate activity of c-Src kinase, and pSlience4.1-ShSrc to knock it down. The expressions of c-Src kinase and molecular markers of EMT such as E-cadherin, ZO-1, α-SMA, and Vimentin were examined at 48 h by RT-PCR and western blot. At 48 h and 72 h of transfection, cell proliferation was detected by MTT, and cell mobility and migration were determined by scratch and transwell assays. RESULTS: Activity of c-Src kinase, which causes the expression of p-Src418, was upregulated by different inflammatory factors and high glucose in HLE-B3 cells. When HLE-B3 cells were transfected with pCDNA3.1-SrcY530F, the expression of c-Src kinase was upregulated on both mRNA and protein levels, and activity of c-Src kinase, expression of p-Src418 increased. The expressions of both E-cadherin and ZO-1 were suppressed, while the expressions of vimentin and α-SMA were elevated on both mRNA and protein levels at the same time. Cell proliferation, mobility and migration increased along with activation of c-Src kinase. Conversely, when HLE-B3 cells were transfected with pSlience4.1-ShSrc, both c-Src kinase and p-Src418 expressions were knocked down. The expressions of E-cadherin and ZO-1 increased, but the expressions of Vimentin and α-SMA decreased; meanwhile, cell proliferation, mobility and migration reduced. CONCLUSIONS: The c-Src kinase in lens epithelial cells is easily activated by external stimuli, resulting in the induction of cell proliferation, mobility, migration and EMT.

Mutation in the mouse histone gene Hist2h3c1 leads to degeneration of the lens vesicle and severe microphthalmia.

During an ENU (N-ethyl-N-nitrosourea) mutagenesis screen, we observed a dominant small-eye mutant mouse with viable homozygotes. A corresponding mutant line was established and referred to as Aey69 (abnormality of the eye #69). Comprehensive phenotyping of the homozygous Aey69 mutants in the German Mouse Clinic revealed only a subset of statistically significant alterations between wild types and homozygous mutants. The mutation causes microphthalmia without a lens but with retinal hyperproliferation. Linkage was demonstrated to mouse chromosome 3 between the markers D3Mit188 and D3Mit11. Sequencing revealed a 358 A-> C mutation (Ile120Leu) in the Hist2h3c1 gene and a 71 T-> C (Val24Ala) mutation in the Gja8 gene. Detailed analysis of eye development in the homozygous mutant mice documented a perturbed lens development starting from the lens vesicle stage including decreasing expression of crystallins as well as of lens-specific transcription factors like PITX3 and FOXE3. In contrast, we observed an early expression of retinal progenitor cells characterized by several markers including BRN3 (retinal ganglion cells) and OTX2 (cone photoreceptors). The changes in the retina at the early embryonic stages of E11.5-E15.5 happen in parallel with apoptotic processes in the lens at the respective stages. The excessive retinal hyperproliferation is characterized by an increased level of Ki67. The hyperproliferation, however, does not disrupt the differentiation and appearance of the principal retinal cell types at postnatal stages, even if the overgrowing retina covers finally the entire bulbus of the eye. Morpholino-mediated knock-down of the hist2h3ca1 gene in zebrafish leads to a specific perturbation of lens development. When injected into zebrafish zygotes, only the mutant mouse mRNA leads to severe malformations, ranging from cyclopia to severe microphthalmia. The wild-type Hist2h3c1 mRNA can rescue the morpholino-induced defects corroborating its specific function in lens development. Based upon these data, it is concluded that the ocular function of the Hist2h3c1 gene (encoding a canonical H3.2 variant) is conserved throughout evolution. Moreover, the data highlight also the importance of Hist2h3c1 in the coordinated formation of lens and retina during eye development.

The Function of Thioredoxin-Binding Protein-2 (TBP-2) in Different Diseases.

Thioredoxin-binding protein-2 (TBP-2) has an important role in the redox system, but it plays a different role in many different diseases (e.g., various cancers, diabetes mellitus (DM), cardiovascular disease, and cataracts) by influencing cell proliferation, differentiation, apoptosis, autophagy, and metabolism. Distinct transcription factors (TFs) stimulated by different factors combine with binding sites or proteins to upregulate or downregulate TBP-2 expression, in order to respond to the change in the internal environment. Most research disclosed that the main function of TBP-2 is associating with thioredoxin (Trx) to inhibit the antioxidant capacity of Trx. Furthermore, the TBP-2 located in tissues, whether normal or abnormal, has the ability to cause the dysfunctioning of cells and even death through different pathways, such as shortening the cell cycle and inducing apoptosis or autophagy. Through these studies, we found that TBP-2 promoted the development of diseases which are involved in inflammatory and oxidative damage. To a certain extent, we believe that there is some hidden connection between the biological functions which TBP-2 participates in and some distinct diseases. This review presents only a summary of the roles that TBP-2 plays in cancer, DM, cataracts, and so on, as well as its universal mechanisms. Further investigations are needed for the cell signaling pathways of the effects caused by TBP-2. A greater understanding of the mechanisms of TBP-2 could produce potential new targets for the treatment of diseases, including cancer and diabetes, cardiovascular disease, and cataracts.

The Effects of Maternal Under-Nutrition and a Post-Natal High Fat Diet on Lens Growth, Transparency and Oxidative Defense Systems in Rat Offspring.

PURPOSE: A poor early life nutrition environment is well established to result in a range of cardiometabolic disorders in offspring in later life. These effects can be exacerbated via exposure to an obesogenic dietary environment. To date, the effect of maternal diet and/or a post-natal obesogenic nutritional environment on key characteristics related to lens growth and oxidative stress has not been undertaken. The present study, therefore, examined the characteristics and oxidative status of the lens. MATERIALS AND METHODS: Using a model of moderate maternal under-nutrition, rat dams were fed either a control diet (100% ad libitum, CON) or undernourished throughout pregnancy (50% of ad libitum intake, UN) and offspring fed either a control (5% fat, C) or high fat (30% fat, HF) diet post-weaning, resulting in four nutritional groups; CON-C, CON-HF, UN-C, and UN-HF. Offspring lenses were extracted at 160 days of age, weighed, imaged under dark and bright field microscopy, and then dissected into cortical and core fractions for biochemical analyses of oxidative stress markers. RESULTS: Our findings reveal that lenses from all groups were transparent. However, gender specific changes were evident at the biochemical level with increased oxidative stress detected in the cortex and core of female but not male UN-C lenses, and in the cortex of male but not female CON-HF lenses. The greatest increase in oxidative stress was detected in the UN-HF group in the cortex and core regions of the lens and for both genders. CONCLUSIONS: These findings show that oxidative stress is exacerbated in the lens as a result of a combination of altered pre-natal and post-natal diet. This demonstrates a novel interaction between the two developmental windows and warrants further investigations toward devising appropriate nutritional strategies for minimizing oxidative stress in the lens.

Upregulation of multiple signaling pathways by Dock5 deletion in epithelial cells.

Purpose: Rupture of lens cataract (RLC) is a hereditary mouse model that shows spontaneous rupture of the lens at the posterior pole at 45-100 days of age. The responsible gene for this phenotype was identified as Dock5, a guanine nucleotide exchange factor for small GTPase Rac1. This study was performed to elucidate the pathway initiating this phenotype. Methods: We examined the RNA expression by microarray in lens epithelial cells (LECs) from wild-type and RLC mice at the pre-rupture age of 21 days. We applied the list of altered genes to an Ingenuity Pathway Analysis (IPA) to predict the pathways that are altered upon dedicator of cytokinesis-5 (Dock5) protein loss. The activation status of the predicted pathways was examined by western blotting in the cultured epithelial cells treated with a Dock5 inhibitor. Results: The highest-scored network was "Antimicrobial Response, Inflammatory Response, Dermatological Diseases and Conditions." In that network, it is predicted that extracellular signal-regulated kinase (Erk) is activated in LECs from RLC mice. Our test confirmed that Erk was more phosphorylated in the LECs at the equator in both Dock5-knockout mice and RLC mice. In an in vitro experiment of the cultured epithelial cells, the inhibition of Dock5 activity significantly induced Erk activation. It was also confirmed that Akt (cellular homolog of murine thymoma virus akt8 oncogene, also called protein kinase B) and nuclear factor-kappa B (NFκB), predicted to be the key molecules in two other high-scoring networks by IPA, were activated upon Dock5 inhibition in the cultured epithelial cells. Conclusions: Dock5 participates in epithelial cell maintenance by regulating gene expression.

Identification and Functional Characterization of a GSH Conjugate Efflux Pathway in the Rat Lens.

PURPOSE: To identify and functionally characterize transporters involved in the release of glutathione (GSH) conjugates from the rat lens. METHODS: Polymerase chain reaction and Western blotting were used to screen for the presence of multidrug resistance-associated protein (Mrp) and organic anion transporting polypeptide (Oatp) isoforms, and immunohistochemistry used to localize Mrp isoforms. To test for Mrp function, lenses were loaded with 5-chloromethylfluorescein diacetate and monochlorobimane to form the fluorescent GSH conjugates glutathione methylfluorescein (GS-MF) and glutathione bimane (GS-B), respectively, and cultured in artificial aqueous humour (AAH) in the presence or absence of MK571, an Mrp-specific inhibitor, or benzbromarone, a nonspecific organic anion transporter inhibitor. Glutathione-MF and GS-B fluorescence were measured in the AAH media and lenses. RESULTS: Multidrug resistance-associated proteins 1, 4, 5, and Oatp1a4 were present at the transcript level, but only Mrp1, 4, and 5 were detected at the protein level. Multidrug resistance-associated proteins 1 and 5 localized to the epithelium and peripheral fiber cells, whereas Mrp4 strongly labeled the nuclei. Glutathione-MF and GS-B efflux was significantly decreased and accumulation in the lens significantly increased in the presence of MK571, indicating that the Mrps are the predominant transporters involved in GSH conjugate release from the lens. Glutathione-B conjugate efflux was further inhibited in the presence of benzbromarone, suggesting that alternative organic anion pathways were involved in mediating GS-B efflux. CONCLUSIONS: Multidrug resistance-associated proteins are present in the lens and may be used to remove endogenous and exogenous compounds from the lens via GSH conjugation. This may represent an important pathway of detoxification required to minimize oxidative stress and maintain lens homeostasis.

FE65 and FE65L1 amyloid precursor protein-binding protein compound null mice display adult-onset cataract and muscle weakness.

FE65 and FE65L1 are cytoplasmic adaptor proteins that bind a variety of proteins, including the amyloid precursor protein, and that mediate the assembly of multimolecular complexes. We previously reported that FE65/FE65L1 double knockout (DKO) mice display disorganized laminin in meningeal fibroblasts and a cobblestone lissencephaly-like phenotype in the developing cortex. Here, we examined whether loss of FE65 and FE65L1 causes ocular and muscular deficits, 2 phenotypes that frequently accompany cobblestone lissencephaly. Eyes of FE65/FE65L1 DKO mice develop normally, but lens degeneration becomes apparent in young adult mice. Abnormal lens epithelial cell migration, widespread small vacuole formation, and increased laminin expression underneath lens capsules suggest impaired interaction between epithelial cells and capsular extracellular matrix in DKO lenses. Cortical cataracts develop in FE65L1 knockout (KO) mice aged 16 months or more but are absent in wild-type or FE65 KO mice. FE65 family KO mice show attenuated grip strength, and the nuclei of DKO muscle cells frequently locate in the middle of muscle fibers. These findings reveal that FE65 and FE65L1 are essential for the maintenance of lens transparency, and their loss produce phenotypes in brain, eye, and muscle that are comparable to the clinical features of congenital muscular dystrophies in humans.

Adhesion of heavy silicone oil to the anterior surfaces of the posterior lens capsule.

PURPOSE: To report a case of heavy silicone oil adhesion to the anterior surfaces of posterior lens capsule.
 METHODS: Descriptive case report.
 RESULTS: A healthy 56-year-old pseudophakic man presented with visual disturbance in his right eye for a week. There was a large irregular retinal tear at 5-7 o'clock, mild vitreous hemorrhage, and total retinal detachment. He underwent 23-G pars plana vitrectomy and heavy silicone oil tamponade was injected. The retina remained attached postoperatively and heavy silicone oil was removed 2 months later. Anatomic and functional success was achieved and his vision had improved. Five months later, he presented with blurred and decreased vision secondary to tiny droplets of heavy silicone oil at the anterior surfaces of the posterior capsule. After applying Nd:YAG laser capsulotomy, visual acuity improved and stayed stable during 1 year follow-up. 
 CONCLUSIONS: Heavy silicone oil adhesion to the anterior surfaces of the posterior lens capsule has not been reported before. This complication may be seen rarely and treated by Nd:YAG laser capsulotomy successfully.

Phacolytic glaucoma: are there 2 forms?

We report a case of acute phacolytic glaucoma in which only protein was present in the anterior chamber without macrophages. We propose that this study represents a type of phacolytic glaucoma characterized by a hyperacute presentation caused by rapid leakage of degenerated lens proteins into the aqueous humor as opposed to a second type with a more gradual onset and with phacolytic macrophages in the aqueous humor resulting from an immunologic response to liquefied lens proteins. Thus, 2 forms, perhaps at ends of a spectrum of clinical manifestations of phacolytic glaucoma, may exist with distinct characteristics and pathophysiology.

Copper deposition in a variant of multiple myeloma: pathologic changes in the cornea and the lens capsule.

PURPOSE: To report the pathologic changes in the cornea and the lens capsule resulting from copper deposition in a variant of multiple myeloma. METHODS: Case report. RESULTS: Light microscopy of the cornea revealed endothelial cell attenuation with diffuse copper deposition in the central Descemet membrane, which showed thinning, whereas copper banding was seen in the midperipheral and peripheral cornea where the Descemet membrane was normal in thickness. Copper deposition was confirmed by x-ray microanalysis. The anterior lens capsule showed subepithelial copper deposits. Thickening, multilayering, and splitting of the lens capsule were also noted. CONCLUSIONS: We report the pattern of deposition of copper in the Descemet membrane of the cornea and the anterior lens capsule in multiple myeloma, associated with hypercupremia. Descemet membrane thinning and regional differences in copper deposition were noted. Also, thickening and splitting of the lens capsule are a novel observation.

Integrins in lens development and disease.

Integrins are the major cell surface receptors for proteins in the extracellular matrix. These receptors form major cell signaling centers that are bidirectional, communicating messages between the cell and its environment. They are a large receptor family, with members well-known to regulate cellular processes essential to both development and disease. In this review we examine the literature regarding integrins in the lens. Here we cover integrin function in lens cell differentiation, in the development of the lens and in protection of the lens epithelial cell phenotype. In addition, we analyze the role of integrins in the progression of lens fibrotic diseases, focusing particularly on integrin regulation of TGFbeta signaling pathways in posterior capsule opacification (PCO) and anterior subcapsular cataract (ASC).

Pertussis toxin is superior to TLR ligands in enhancing pathogenic autoimmunity, targeted at a neo-self antigen, by triggering robust expansion of Th1 cells and their cytokine production.

Microbial products are assumed to play a major role in triggering pathogenic autoimmunity. Recently accumulated data have shown that these products stimulate the immune system by interacting with TLRs, expressed on APCs. To examine the capacity of various TLR ligands to trigger pathogenic autoimmunity, we used a system in which naive CD4 cells, specific against hen egg lysozyme (HEL), are injected into recipient mice expressing HEL in their eyes. Only when stimulated, the naive cells acquire pathogenic capacity and induce ocular inflammation. Seven TLR ligands were tested in this system: lipoteichoic acid/peptidoglycan, zymosan, poly (I:C), LPS, pertussis toxin (PTX), flagellin, and CpG oligodeoxynucleotide. Treatment of recipient mice with HEL alone stimulated proliferation of the transferred cells, but no disease, whereas ocular inflammation did develop in recipient mice coinjected with HEL and any one of the seven TLR ligands. Inflammation induced by PTX surpassed by its severity those induced by all other tested TLR ligands and was accompanied by a dramatic increase in number of the transferred cells that acquired features of effector Th1 lymphocytes. Ocular inflammation and number of transferred cells in recipients injected with PTX and HEL were substantially reduced by treatment with Abs against IFN-gamma or IL-12, thus indicating the role of these cytokines in the PTX effect. Overall, our observations demonstrate that various TLR ligands are capable of triggering pathogenic autoimmunity and that PTX surpasses other microbial products in this activity, by stimulating excessive proliferation and polarization toward Th1 of naive T cells.

Pyridoxamine inhibits maillard reactions in diabetic rat lenses.

PURPOSE: Advanced glycation end products (AGEs) play an important role in protein modification during cataract formation. Along with sugars, alpha-dicarbonyl compounds, such as methylglyoxal (MGO), have been implicated in AGE formation. Here we report the effect of pyridoxamine (PM) on AGEs and AGE-precursor-metabolizing enzymes in diabetic rat lenses and organ-cultured rat lenses. METHODS: Diabetes was induced in rats by injecting streptozotocin. Diabetic and nondiabetic control rats were treated with PM in drinking water for 20 weeks. Rat lenses were organ cultured with normal or high glucose. We measured lens glutathione (GSH), MGO, AGEs and activities of aldose reductase and glyoxalase I. RESULTS: Treatment of diabetic rats with PM inhibited both argpyrimidine and pentosidine formation when compared to untreated diabetic animals and nondiabetic control animals. Incubation of lenses with 30 mMD-glucose caused an elevation of these AGEs. Addition of 250 muM PM along with glucose resulted in inhibition of AGE formation in organ-cultured lenses. The glyoxalase I activity was significantly reduced in diabetic rats; PM treatment inhibited such a reduction. The activity of aldose reductase was elevated in diabetic lenses; PM treatment further enhanced its activity. CONCLUSION: Our results suggest that PM can inhibit AGE formation in the diabetic lens by enhancing the activity of aldose reductase and reacting with precursors of AGEs.

Late-onset macular degeneration and long anterior lens zonules result from a CTRP5 gene mutation.

PURPOSE: To identify the gene responsible for a complex ocular phenotype of late-onset macular degeneration, long anterior zonules (LAZ), and elevated intraocular pressure (IOP) and to study its expression. METHODS: Ocular examination, visual field, fluorescein angiography, and electrophysiology testing were performed. One affected individual was treated with vitamin A. DNA from 55 family members (UM:H389) was used for linkage, mapping, and mutation analysis. Linkage analysis of macular degeneration and LAZ phenotypes was performed independently. Mutations in candidate genes were screened by sequencing. mRNA expression of CTRP5 and MFRP, which are bicistronic genes, was studied by semiquantitative RT-PCR (qRT-PCR) in various human tissues. CTRP5 expression was also evaluated by in situ hybridization. RESULTS: Affected members had LAZ detectable by the third decade and/or macular degeneration by the fourth to fifth decade. A six-month treatment with vitamin A shortened dark adaptation considerably in one affected member. Both conditions mapped independently with zero recombination to 11q23, with maximum lod scores of 3.31 for macular degeneration and 5.41 for LAZ. The same CTRP5 missense mutation was identified in all affected individuals. Retinal pigment epithelium (RPE) and ciliary epithelium (CE) showed highest CTRP5 transcript expression, which was also true for MFRP. CTRP5 tissue expression was confirmed by in situ hybridization. CONCLUSIONS: A single locus at 11q23 is implicated in a complex ocular phenotype involving RPE and CE, tissues of neuroectodermal origin. All individuals with either LAZ and/or macular degeneration carry the same CTRP5 S163R mutation, which is transmitted in autosomal dominant manner.