Association between ambient air pollution and dry eye symptoms among Chinese individuals during the COVID-19 pandemic: A national-based study.

PURPOSE: To examine the association between ambient air pollution and dry eye symptoms (DES) during the COVID-19 pandemic and explore whether air pollution had increased the risk of DES to a greater extent than other risk factors. METHODS: A nationwide cross-sectional survey was conducted from June 20, 2022 to August 31, 2022. The Ocular Surface Disease Index-6 (OSDI-6) questionnaire was used to assess the presence of DES. Logistic regression models were employed to analyze the associations between DES and air pollution variables, including air quality index (AQI), fine particulate matter (PM2.5), PM10, sulfur dioxide (SO2), carbon monoxide (CO), nitrogen dioxide (NO2), ozone (O3) and residing near industrial zones. We explored the interactions of air pollutants and other risk factors in the additive models by calculating the synergy index (SI). Standardized regression coefficients were calculated to compare the relative importance of risk factors for DES. RESULTS: A total of 21,909 participants were included in the analysis. Residing near industrial zones was significantly correlated with a higher risk of DES (Odds ratio (OR): 1.57, 95 % confidence interval (CI): 1.38-1.79). No significant associations were found between DES and air pollutants except SO2 (OR: 1.05, 95 % CI: 1.02-1.09, per standard deviation increment in SO2 concentration). The restricted cubic spline analyses revealed a linear concentration-response relationship between SO2 and DES. The interaction analyses suggested synergetic interactions of SO2 with depression and problematic internet use. Among the risk factors, depression, anxiety and problematic Internet use contributed more to the increased risk of DES. CONCLUSION: The association between ambient air pollutants and DES may have been mitigated during the pandemic due to increased time spent indoors. Despite this, our findings support the deleterious health impact of air pollutants. Future urban planning should plan industrial zones further away from residential areas.

Effects of Toll-like receptor 1 and 2 agonist Pam3CSK4 on uveal melanocytes and relevant experimental mouse model.

Pam3CSK4 activates Toll-like receptors 2 and 1 (TLR1/2), which recognize mainly molecules from gram-positive pathogens. The effect of Pam3CSK4 on various cytokine and chemokine expression in cultured human uveal melanocytes (UM) has not been studied systematically. The purpose of this study was to investigate the mechanistic expressions of seven cytokines and chemokines of interleukin- (IL-) 6, IL-10, MCP-1 (CCL-2), CXCL-1 (GRO-α), CXCL-8 (IL-8), interferon-gamma (IFN-γ), and tumor necrosis factor-alpha (TNF-α) in UM. These cytokines are reported to be increased in intraocular fluids or tissues of the patients with endophthalmitis and non-infectious uveitis, as well as in various experimental animal uveitic models in the literature. Flow cytometry was used to measure the effects of Pam3CSK4 on the expression of TLR1/2 in UM. ELISA and Real-time PCR analysis were used to estimate the ability of Pam3CSK4 to elevate these cytokines and chemokines levels in conditioned media and cell lysates of UM, respectively. Flow cytometry measured and compared the phosphorylated MAPK pathway and activated NF-κB signals pathway in UM, treated with and without Pam3CSK4. ELISA analysis tested the effect of various signal inhibitors (ERK1/2, JNK1/2, p38 and NF-κB) on Pam3CSK4-induced IL-6 levels in cultured UM. The role of TLR2 in Pam3CSK4-induced acute anterior uveitis in experimental mouse model was tested in TLR2 knockout (TLR2 KO) mice and their wild-type C57Bl/6 controls. Pam3CSK4 increased the expression of TLR1/2 proteins in cultured UM. Pam3CSK4 significantly elevated the IL-6, MCP-1, CXCL-1, CXCL-8 protein, and mRNA levels in cultured UM, but not IL-10, TNF-α, or IFN-γ. Pam3CSK4 activated NF-κB, ERK, JNK, and p38 expression. Pam3CSK4-induced expression of IL-6 was decreased by NF-κB, ERK, INK, and p38 inhibitors; especially the NF-κB inhibitor, which can completely block the IL-6 stimulation. Intravitreal injection of Pam3CSK4 induced acute anterior uveitis in C57Bl/6 mice, this effect was significantly reduced in TLR2 KO mice. TLR1/2 plays an important role against invading pathogens, especially gram-positive bacteria; but an excessive reaction to molecules from gram-positive bacteria may promote non-infectious uveitis. UM can produce IL-6, MCP-1, CXCL-1, and CXCL-8, and are one of the target cells of TNF-α and IFN-γ. TLR-2 inhibitors might have a beneficial effect in the treatment of certain types of uveitis and other ocular inflammatory-related diseases and warrant further investigation.

NSUN2-mediated RNA m5C modification modulates uveal melanoma cell proliferation and migration.

RNA 5-methylcytosine (m5C) is a widespread post-transcriptional modification involved in diverse biological processes through controlling RNA metabolism. However, its roles in uveal melanoma (UM) remain unknown. Here, we describe the biological roles and regulatory mechanisms of RNA m5C in UM. Initially, we identified significantly elevated global RNA m5C levels in both UM cells and tissue specimens using ELISA assay and dot blot analysis. Meanwhile, NOP2/Sun RNA methyltransferase family member 2 (NSUN2) was upregulated in both types of these samples, whereas NSUN2 knockdown significantly decreased RNA m5C level. Such declines inhibited UM cell migration and suppressed cell proliferation through cell cycle G1 arrest. Furthermore, bioinformatic analyses, m5C-RIP-qPCR, and luciferase assay identified ß-Catenin (CTNNB1) as a direct target of NSUN2-mediated m5C modification in UM cells. Additionally, overexpression of miR-124a in UM cells diminished NSUN2 expression levels indicating that it is an upstream regulator of this response. Our study suggests that NSUN2-mediated RNA m5C methylation provides a potential novel target to improve the therapeutic management of UM pathogenesis.

Toll-like receptor 2 and 6 agonist fibroblast-stimulating lipopeptide increases expression and secretion of CXCL1 and CXCL2 by uveal melanocytes.

Fibroblast-stimulating lipopeptide (FSL-1) can activate Toll-like receptor 2 and 6 (TLR2/6), which recognize relevant molecules from gram-positive pathogens, fungus, and mycoplasma, and elevates the expression of CXCL1 and CXCL2, neutrophil chemoattractants, in certain types of cells. This effect has not previously been reported in the uveal melanocytes (UM). This study was designed to test the hypothesis that FSL-1 can induce the expression and secretion of CXCL1 and CXCL2 via activation of TLR2/6 in cultured human UM and producing an acute non-infectious uveitis reaction in the mouse. Flow cytometry and fluorescent immunostaining were used to measure the effect of FSL-1 on the expression of TLR2/6 in UM. Real time PCR and ELISA analysis were used to assess the ability of FSL-1 to elevate CXCL1/CXCL2 levels in cell lysates and conditioned media of UM, respectively. Flow cytometry measured phosphorylated MAPK and activated NF-κB signals in UM, with and without FSL-1 treatment. ELISA analysis tested the impact of various signal inhibitors (NF-κB, p38 MAPK, JNK1/2 and ERK1/2) and TLR2/6 antagonists on FSL-1-induced CXCL1/CXCL2 levels in cultured UM. The effects of neutralizing antibodies to TLR2 on FSL-1-induced mouse uveitis were tested in an experimental animal model. FSL-1 induced the expression of TLR2/6 proteins in cultured UM. FSL-1 significantly elevated the CXCL1 and CXCL2 proteins and mRNA levels in cultured UM time- and dose-dependently. FSL-1 mainly activated NF-κB, JNK, and expression of TLR2. FSL-1-induced expression of CXCL1 and CXCL2 was blocked by NF-κB, JNK, ERK inhibitors and TLR2 antagonists. Intravitreal injection of FSL-1 induced acute non-infectious mouse uveitis, which was significantly reduced in severity by a TLR2 antagonist. These results suggest that UM may play a role in the immune reaction, which targets invading pathogens, especially gram-positive bacteria. On the other hand, an excessive reaction to molecules from gram-positive bacteria may promote an inflammatory state of non-infectious uveitis.

Cultured Human Uveal Melanocytes Express/secrete CXCL1 and CXCL2 Constitutively and Increased by Lipopolysaccharide via Activation of Toll-like Receptor 4.

Purpose: Lipopolysaccharide (LPS) can activate Toll-like receptor 4 (TLR4) and increase the expression of CXCL1 and CXCL2, the potent neutrophils chemoattractants, in various cell types. These effects have not been previously reported in the uveal melanocytes. This study was designed to investigate the effects of LPS on the activation of TLR4 and expression of CXCL1/CXCL2 in cultured human uveal melanocytes and the relevant signal pathways.Methods: Effects of LPS on the expression of TLR4 were tested using real-time PCR, flow cytometry and fluorescence immunostaining. Effects of LPS-induced expression/secretion of CXCL1/CXCL2 were studied using real-time PCR in cell lysates and ELISA in conditioned media of cultured uveal melanocytes. Activated NF-κB and phosphorylated MAPK signals were tested in cells with and without LPS treatment using flow cytometry. Effects of various signal inhibitors on p38, ERK1/2, JNK1/2 and NF-κB on the secretion of CXCL1/CXCL2 were tested by ELISA. The effects of neutralized antibodies of CXCL1/CXCL2 on the severity of LPS-induced uveitis were tested in a mouse model.Results: LPS stimulation increased the expression of TLR4 mRNA and protein in culture uveal melanocytes. Constitutive secretion of CXCL1/CXCL2 was detected in uveal melanocytes and was significantly increased dose- and time-dependently by LPS stimulation. LPS mainly increased the activated NF-κB and phosphorylated JNK1/2. LPS-induced expression of CXCL1/CXCL2 was blocked by NF-κB and JNK1/2 inhibitors. The severity of LPS-induced uveitis was significantly inhibited by neutralizing antibody to CXCL1/CXCL2Conclusions: This is the first report on the LPS-induced expression of CXCL1 and CXCL2 by uveal melanocytes via the activation of TLR4. These results suggest that uveal melanocytes may play a role in the immune reaction that eliminates the invading pathogens. Conversely, an excessive LPS-induced inflammatory reaction may also lead to the development of inflammatory ocular disorders, such as non-infectious uveitis.

Beta-adrenergic agonist protects retinal pigment epithelium against hydroxycholoroquine toxicity via cAMP-PKA signal pathway.

AIM: To test our hypothesis that activation of protein kinase A (PKA) signal pathway by ß-adrenergic agonist plays an important role in the protecting of cultured retinal pigment epithelial (RPE) cells against the hydroxychloroquine (HCQ) toxicity. METHODS: Cultured human RPE cells were treated with 1) HCQ, 2) HCQ with salbutamol (a ß2-adrenergic receptor agonist), and 3) HCQ with salbutamol and a PKA inhibitor, and compared these to 4) untreated cells (controls). After treated for 24h, cell vacuolation, cells viability, PKA and PKA kinase activity levels were determined by the measurement of the size of vacuoles using Image J software, the cell counting with a dye-exclusion testing, Western blot and PKA kinase detection, respectively. RESULTS: Cell vacuolation and cell death of cultured RPE cells were significantly increased by the treatment of HCQ. Salbutamol significantly elevated PKA and PKA activity levels and this was associated with the inhibition of the vacuolation and cell death. The PKA inhibitor significantly decreased the PKA levels and eliminated the protective effects of salbutamol on HCQ-treated RPE cells. CONCLUSION: The PKA pathway plays an important role in the protective effects of ß2-adrenergic agonist on the RPE cells against HCQ toxicity. These findings reveal a novel potential strategy against HCQ retinopathy by treatment with PKA activating medications.

Quantitative Study of Human Scleral Melanocytes and Their Topographical Distribution.

PURPOSE: While fibroblasts constitute the main cell component of the sclera, the purpose of the present study was to investigate the cell densities of melanocytes at different regions of the sclera, and to compare them with associated scleral fibroblast densities in human donor eye sections. METHODS: . Paraffin-embedded sections of sclera from 21 human eyes were stained with hematoxylin-eosin (H&E) and immunohistochemical staining (S-100/AEC). Scleral melanocyte and fibroblast numbers were counted in different regions of the sclera. The relationship between the melanocyte density and iris pigmentation was also analyzed. RESULTS: . Melanocytes were found in the posterior region of the sclera, especially around the vessels and nerves in emmissarial canals, whereas no or rare melanocytes were found in equatorial and anterior regions. In H&E sections, melanocyte densities in eyes with light-colored irides were significantly less than in eyes with medium or dark-colored irides (P < .05). In S-100-stained sections, more melanocytes could be detected than those in the H&E sections in light-colored eyes (P < .05), but not in medium or dark-colored eyes (P > .05). The numbers of scleral fibroblasts were relatively stable in different regions. In the posterior scleral region, the numbers of fibroblasts were slightly higher than the number of melanocytes, however, this differences were not statistically significant (P > .05). CONCLUSION: . Notable numbers of melanocytes were present in the posterior sclera suggesting that these cells may play a role in ocular physiology and in the pathogenesis of various disorders of the sclera.

RNA m6 A methylation regulates uveal melanoma cell proliferation, migration, and invasion by targeting c-Met.

N6 -methyladenosine (m6 A) is a novel epitranscriptomic marker that contributes to regulating diverse biological processes through controlling messenger RNA metabolism. However, it is unknown if m6 A RNA methylation affects uveal melanoma (UM) development. To address this question, we probed its function and molecular mechanism in UM. Initially, we demonstrated that global RNA m6 A methylation levels were dramatically elevated in both UM cell lines and clinical specimens. Meanwhile, we found that METTL3, a main m6 A regulatory enzyme, was significantly increased in UM cells and specimens. Subsequently, cycloleucine (Cyc) or METTL3 targeted small interfering RNA was used to block m6 A methylation in UM cells. We found that Cyc or silencing METTL3 significantly suppressed UM cell proliferation and colony formation through cell cycle G1 arrest, as well as migration and invasion by functional analysis. On the other hand, overexpression of METTL3 had the opposite effects. Furthermore, bioinformatics and methylated RNA immunoprecipitation-quantitative polymerase chain reaction identified c-Met as a direct target of m6 A methylation in UM cells. In addition, western blot analysis showed that Cyc or knockdown of METTL3 downregulated c-Met, p-Akt, and cell cycle-related protein levels in UM cells. Taken together, our results demonstrate that METTL3-mediated m6 A RNA methylation modulates UM cell proliferation, migration, and invasion by targeting c-Met. Such a modification acts as a critical oncogenic regulator in UM development.

miR-142-3p suppresses uveal melanoma by targeting CDC25C, TGFßR1, GNAQ, WASL, and RAC1.

Purpose: Uveal melanoma (UM) is the most frequent metastatic ocular tumor in adults. Therapeutic intervention remains ineffective since none of the novel procedures used to treat this disease increased survival rates. To deal with this limitation, additional studies are required to clarify its pathogenesis. The current study focused on describing how epigenetic modulation by miR-142-3p affects changes in some cellular functions underlying UM pathogenesis. Methods and results: Microarray analysis identified 374 miRNAs which were differentially expressed between UM cells and uveal melanocytes. miR-142-3p was one of the 10 most downregulated miRNAs. Quantitative RT-PCR analysis confirmed that miR-142-3p expression levels were significantly decreased in both UM cell lines and clinical specimens. The results of the MTS, clone formation, scratch wound, transwell assays, and in vivo biofluorescence imaging showed that miR-142-3p overexpression significantly inhibited cell proliferation, migration, and invasiveness. Nevertheless, miR-142-3p did not affect cell apoptotic activity or sensitivity to doxorubicin. Cell cycle and EdU analysis showed that miR-142-3p overexpression induced G1/G2 cell cycle arrest and reduced DNA synthesis in UM cells. Microarray analysis showed that miR-142-3p mainly regulates the TGFß signaling pathway, and those in which MAPK and PI3K-Akt are constituents. Functional interactions between miR-142-3p and CDC25C, TGFßR1, GNAQ, WASL, and RAC1 target genes were confirmed based on the results of the luciferase reporter assay and Western blot analysis. CDC25C or RAC1 downregulation is in agreement with cell cycle arrest and DNA synthesis disorder induction, while downregulation of TGFßR1, GNAQ, WASL, or RAC1 accounts for declines in cell migration. Conclusion: miR-143-3p is a potential therapeutic target to treat UM since overriding its declines in expression that occur in this disease reversed the pathogenesis of this disease. Such insight reveals novel biomarker for decreasing UM vitality and for improved tracking of tumor progression.

Iris colour and astigmatism among Chinese teenagers.

BACKGROUND/AIMS: Iris colour might contribute to refractive development, but it is uncertain whether it is related to astigmatism. We aim to examine the association of iris colour with the presence of astigmatism in a school-based sample of Chinese students. METHODS: 2346 grade 7 students from 10 middle schools aged 13 to 14 years in Southwestern China participated in the study. We obtained standardised slit-lamp photographs and developed a grading system assessing iris colour (higher grade denoting darker). Astigmatism was defined as a cylinder power of more than 0.50, 0.75 or 1.00 dioptre (D). Logistic regression models with generalised estimating equation were fitted to assess the relationship between iris colour and astigmatism, accounting for the correlation between both eyes. ORs and 95% CIs were presented. RESULTS: The overall prevalence of astigmatism for three different definitions was 30.4% (95% CI 28.6% to 32.2%) (<-0.5 D), 12.7 % (95% CI 11.3% to 14.0%) (<-0.75 D) and 5.3% (95% CI 4.4% to 6.2%) (<-1.0 D), respectively. In multivariate analysis adjusting for the effect of gender and height, darker iris colour was associated with an increasing trend of astigmatism (p for trend <0.05). Compared with individuals with iris colour of grade 4 or 5 (the darkest), those with grade 1 or 2 (the lightest) were significantly less likely to be affected by astigmatism (<-0.75 D) in gender-adjusted model (OR 0.67) and multivariate-adjusted model (OR 0.72). CONCLUSION: Darker iris colour might be a risk factor for astigmatism in Chinese adolescents.

Iris Color and Lens Thickness in Chinese Teenagers.

PURPOSE: We aimed to determine the association of iris color with lens thickness (LT) in a school-based sample of Chinese teenagers. METHODS: In total, 2346 grade 7 students, from 10 middle schools, aged 13 to 14 years in Mojiang located in Southwestern China were included in the analysis. A grading system was developed to assess iris color based on standardized slit-lamp photographs. LT was measured by the LenStar LS900. Refractive error was measured after cycloplegia using an autorefractor and ocular biometric parameters, including axial length (AL), were measured using an IOL Master. RESULTS: There was a significant trend of decreasing LTs with darker iris color. On average, eyes with "grade 1" (the lightest) iris color, when compared with those with "grade 5" (the darkest), had greater LTs (mean difference, 0.1 mm). After adjusting for other potential confounders including sex, height, and ALs in generalized estimating equation models, the trend was similar and did not change significantly. Compared with individuals with iris color of grade 1, those with grade 5 had a thinner lens of 0.1 mm (95% confidence interval [CI]: 0.01, 0.19) in sex-adjusted model and a 0.09 mm (95% CI: 0, 0.18) in multivariate-adjusted model. CONCLUSIONS: Lighter iris color might be associated with greater LTs in Chinese teenagers. The biological mechanisms underlying the association warrant further clarification. TRANSLATIONAL RELEVANCE: As LT is an important refractive component, knowledge on the effect of iris color on LTs may assist in the design of novel technologies, which could control refractive development.

Butein induces apoptotic cell death of human cervical cancer cells.

Butein is a chalcone, a flavonoid that is widely biosynthesized in plants. Butein has been identified to possess varied pharmacological activity and is extractable from traditional Chinese medicinal herbs, therefore applicable for disease treatment. Recently, in vitro and in vivo studies have shown that butein may induce apoptotic cell death in various human cancer cells. In this study we investigated the apoptotic effect of butein and the underlying mechanisms in human cervical cancer cells. Two cell lines, C-33A and SiHa cells, were treated with butein at different dosages for different durations. The effect of butein on cell viability was assessed by MTT assay, which revealed that butein exerted cytotoxicity in both cervical cancer cells in a dose- and time-dependent fashion. Apoptotic pathway-related factors in the butein-treated cervical cancer cells were then examined. JC-1 flow cytometry, cytochrome c assay, and caspase activity assays demonstrated that butein disturbed mitochondrial transmembrane potential, and increased cytosolic cytochrome c levels and caspase activities in both cervical cancer cells. Western blot analysis revealed that butein downregulated anti-apoptotic protein Bcl-xL and led to proteolytic cleavage of poly (ADP-ribose) polymerase. In addition, butein decreased expressions of the inhibitor of apoptosis (IAP) proteins, including X-linked IAP, survivin, and cellular IAP-1. The findings of this study suggest that butein can decrease cervical cancer cell viability via a pro-apoptotic effect, which involves inhibition of the IAP proteins and activation of both extrinsic and intrinsic pro-apoptotic pathways. Therefore, butein may be applicable for cervical cancer treatment.

Uveal melanocytes express high constitutive levels of MMP-8 which can be upregulated by TNF-α via the MAPK pathway.

Matrix metalloproteinase (MMP)-8 is the most potent MMP for degrading collagen type-1 and plays an important role in inflammatory reactions and tissue remolding processes. MMP-8 is expressed mainly by polymorphonuclear leukocytes and is not expressed constitutively by most non-leukocytes. We studied the constitutive and TNF-α-induced expression of MMP-8 in cultured human uveal melanocytes (UM) and the relevant signal pathways involved. Conditioned media and cells were collected from UM and other cell types. MMP-8 proteins and mRNA were measured using ELISA kit, western blot and real time RT-PCR, respectively. Phosphorylated p38 MAPK, ERK1/2, and JNK1/2 were measured by ELISA kit and western blot. Very high levels of MMP-8 proteins and mRNA were detected in the conditioned media and cell lysates in 11 UM cell lines and three uveal melanoma cell lines cultured without serum, but not in media and cell lysates from other ocular resident cells or 12 malignant cell lines from other tissues, with exception of cutaneous melanoma cells. TNF-α moderately increased MMP-8 mRNA and protein levels in a dose- and time-dependent manner, accompanied by a significant increase of phosphorylated JNK1/2 and ERK1/2 in cell lysates. ERK1/2 (U0126) and JNK1/2 (SP600125) inhibitors significantly blocked TNF-α-induced and constitutive expression of MMP-8 in UM. This is the first report on the expression and secretion of MMP-8 by UM and uveal melanoma cells. The data suggest that UM may play a role in the remolding process and pathogenesis of inflammatory-related diseases in the eye via secretion of MMP-8.

Fisetin induces apoptosis through mitochondrial apoptosis pathway in human uveal melanoma cells.

Fisetin, a diatery flavonoid, been reported that possess anticancer effects in various cancers. The purpose of the study was to investigate the antitumor effects of fisetin in cultured uveal melanoma cell lines and compared with normal retinal pigment epithelial (RPE) cells. MTT assay was used for evaluating cytotoxic effects of fisetin. Flow cytometry study was used for the determination of apoptosis. JC-1 fluorescent reader was used to determine mitochondrial transmembrane potential changes. The results shown that fisetin dose-dependently decreased the cell viability of uveal melanoma cells but not influenced the cell viability of RPE cells. Apoptosis of uveal melanoma cells was induced by fisetin efficiently. Fisetin inhibited antiapoptotic Bcl-2 family proteins and damaged the mitochondrial transmembrane potential. The levels of proapoptotic Bcl-2 proteins, cytochrome c, and various caspase activities were increased by fisetin. In conclusion, fisetin induces apoptosis of uveal melanoma cells selectively and may be a promising agent to be explored for the treatment of uveal melanoma.

Iris colour in relation to myopia among Chinese school-aged children.

PURPOSE: Understanding the association of iris colour and myopia may provide further insights into the role of the wavelength of lights in the pathophysiology of myopia. We aim to assess the association of iris colour and myopia in a school-based sample of Chinese students. METHODS: Two thousand three hundred and forty-six Year 7 students from 10 middle schools (93.5% response rate) aged 13-14 years in Mojiang, a small county located in Southwestern China, participated in the study. We obtained standardised slit lamp photographs and developed a grading system assessing iris colour (higher grade denoting a darker iris). Refractive error was measured after cycloplegia using an autorefractor by optometrists or trained technicians. An IOLMaster (www.zeiss.com) was used to measure ocular biometric parameters including axial length (AL). RESULTS: Of all the study participants, 693 (29.5%) were affected by myopia with the prevalence estimates being higher in girls (36.8%; 95% confidence interval [CI]: 34.0, 39.6) than in boys (22.8%; 95% CI: 20.4, 25.1) (p < 0.001). After adjusting for gender, height, parental history of myopia, time spent on computer, time spent watching TV, time spent outdoors, and time spent reading and writing, participants with a darker iris colour tended to have a higher prevalence of myopia, a more myopic refraction and a longer AL. Dose-response relationships were observed in all regression models (p for trend <0.05). CONCLUSIONS: Darker iris colour was associated with more myopic refractive errors and longer ALs among Chinese school-aged children and this association was independent of other known myopia-related risk factors.

Human aqueous humor levels of transforming growth factor-ß2: Association with matrix metalloproteinases/tissue inhibitors of matrix metalloproteinases.

The present study aims to investigate the association of transforming growth factor-ß2 (TGF-ß2) and matrix metalloproteinases (MMPs), MMP-2 and MMP-3, and tissue inhibitors of matrix metalloproteinases (TIMPs), TIMP-1, TIMP-2 and TIMP-3 in the aqueous humor of patients with high myopia or cataracts. The levels of TGF-ß2 and MMPs/TIMPs were measured with the Luminex xMAP Technology using commercially available Milliplex xMAP kits. The association between TGF-ß2 and MMPs/TIMPs levels was analyzed using the Spearmans correlation test. The levels of TGF-ß2 were identified to be positively correlated with the levels of TIMP-1 and TIMP-3 (TIMP-1: r=0.334; P=0.007; TIMP-3: r=0.309; P=0.012). The levels of MMP-2, MMP-3 and TIMP-2 did not significantly correlate with TGF-ß2 levels (P>0.05). A positive correlation was identified between TGF-ß2 and TIMPs in the aqueous humor of human eyes with elongated axial length. It appears that TGF-ß2 stimulates the expression of TIMPs as a compensatory reaction to the development of high myopia.

SKP2 Activation by Thyroid Hormone Receptor ß2 Bypasses Rb-Dependent Proliferation in Rb-Deficient Cells.

Germline RB1 mutations strongly predispose humans to cone precursor-derived retinoblastomas and strongly predispose mice to pituitary tumors, yet shared cell type-specific circuitry that sensitizes these different cell types to the loss of RB1 has not been defined. Here we show that the cell type-restricted thyroid hormone receptor isoform TRß2 sensitizes to RB1 loss in both settings by antagonizing the widely expressed and tumor-suppressive TRß1. TRß2 promoted expression of the E3 ubiquitin ligase SKP2, a critical factor for RB1-mutant tumors, by enabling EMI1/FBXO5-dependent inhibition of SKP2 degradation. In RB1 wild-type neuroblastoma cells, endogenous Rb or ectopic TRß2 was required to sustain SKP2 expression as well as cell viability and proliferation. These results suggest that in certain contexts, Rb loss enables TRß1-dependent suppression of SKP2 as a safeguard against RB1-deficient tumorigenesis. TRß2 counteracts TRß1, thus disrupting this safeguard and promoting development of RB1-deficient malignancies. Cancer Res; 77(24); 6838-50. ©2017 AACR.

Inhibition effect of curcumin on UVB-induced secretion of pro-inflammatory cytokines from corneal limbus epithelial cells.

AIM: To study the effects of curcumin on the secretion of interleukin (IL)-6 and IL-8 by corneal limbus epithelial cells. METHODS: Human corneal limbus epithelial cells were isolated and cultured from donor eyes and irradiated by UVB at different dosages with or without curcumin. MTT test was used for studying the effects of UVB and curcumin on the cell viability. The role of mitogen-activated protein kinase (MAPK) and nuclear factor-kappa B (NF-κB) pathways on the UVB-induced secretion of IL-6 and IL-8 were tested by addition of their inhibitors to the culture with or without UVB-radiation. Levels of various signal pathways, IL-6 and IL-8 in the cells and in the conditioned culture medium were measured by ELISA analysis. RESULTS: UVB at 20 mJ/cm2 or less and curcumin at 20 µmol/L or less did not affect the cell viability of cultured limbus epithelial cells (P>0.05). UVB irradiation at 10 and 20 mJ/cm2 induced a significant increase of secretion of IL-6 and IL-8 and upregulated NF-κB and phosphorylated MAPK pathways of cultured limbus epithelial cells (P<0.05). Various signal pathway inhibitors, including SP600125 (JNK inhibitor), SB203580 (p38 MAPK inhibitor) and BAY11-7082 (NF-κB inhibitor) significantly decreased the UVB-induced secretion of IL-6 and IL-8 secretion (P<0.05). Curcumin at 5-20 µmol/L significantly inhibited UVB-induced secretion of IL-6 and IL-8 by limbus epithelial cells in a dose-dependent manner; while curcumin alone did not affect the secretion of IL-6 and IL-8. The upregulation of NF-κB and MAPK pathways induced by UVB treatment was significantly inhibited by curcumin, suggesting that NF-κB and MAPK pathways are involved in the inhibitory effect of curcumin on UVB-induced production of IL-6 and IL-8. CONCLUSION: Curcumin may be a promising agent to be explored for the prevention and treatment of pterygium.

Regulation of Matrix Metalloproteinase-2 Secretion from Scleral Fibroblasts and Retinal Pigment Epithelial Cells by miR-29a.

PURPOSE: To identify an effective method to prevent myopia progression by characterizing the regulation of matrix metalloproteinase- (MMP-) 2 expression and its secretion from scleral fibroblasts and retinal pigment epithelium (RPE) cells by miR-29a. METHODS: The effects of miR-29a on the growth of scleral fibroblasts and RPE cells were assessed using the cell counting kit-8. The changes in MMP-2 mRNA levels in scleral fibroblasts and RPE cells after transfection with miR-29a mimics or inhibitor were measured by quantitative PCR. Enzyme-linked immunosorbent assays were used to determine the changes in MMP-2 secretion from scleral fibroblasts and RPE cells after transfection with miR-29a mimics or inhibitor. RESULTS: The miR-29a mimics or inhibitor did not significantly alter the growth of scleral fibroblasts or RPE cells at 24, 48, or 72 hours after transfection. MMP-2 mRNA levels were significantly decreased in scleral fibroblasts and RPE cells transfected with the miR-29a mimics. The secretion of MMP-2 by scleral fibroblasts and RPE cells was significantly decreased in cells transfected with the miR-29a mimics. CONCLUSIONS: Suppression of scleral fibroblast and RPE cell expression and secretion of MMP-2 by miR-29a can be used as a therapeutic target for the prevention and treatment of myopia.

Association of Visual Acuity with Ocular Dominance in 2045 Myopic Patients.

PURPOSE: Previous studies of the relationship between visual acuity (VA) and ocular dominance have produced conflicting results. We hypothesized that (1) the discrepancies were related mostly to sample size and interocular visual acuity difference (IOVAD); (2) in large samples of individuals with marked IOVADs, the eye with the better uncorrected distance visual acuity (UDVA) would be dominant. These hypotheses were tested in a large group of myopic patients. METHODS: This prospective study of cycloplegic refraction involved 2045 myopic refractive surgery candidates. Patients with amblyopia or strabismus were excluded. Ocular dominance was assessed using the hole-in-the-card test. RESULTS: In 2045 patients, the dominant eye had significantly better UDVA (p = 0.028) and was less astigmatic (p = 0.000) than the nondominant eye. In 426 patients with marked interocular difference in the UDVA (≥0.2 logMAR), the dominant eye not only had significant UDVA (p = 0.022) but also significantly less myopic (p = 0.028) and had a shorter axial length (AL; p = 0.001). In patients with smaller differences in UDVA (0.1 logMAR, n = 411) or no difference (n = 1208), the dominant and nondominant eyes did not differ significantly with respect to UDVA, myopic power, and AL (p > 0.05). CONCLUSIONS: The present study showed that the dominant eyes had significantly better UDVA than the nondominant eyes, especially in individuals with marked differences in UDVA. These results supported our hypothesis regarding the relationship between better VA and ocular dominance.