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Open Access Publications from the University of California

Scholarly Works (4 results)

  • Article
  • Peer Reviewed
UC Berkeley Previously Published Works (2017)

Purpose

The ocular dimensional changes in myopia reflect increased scleral remodeling, and in high myopia, loss of scleral integrity leads to biomechanical weakening and continued scleral creep. As integrins, a type of cell surface receptors, have been linked to scleral remodeling, they represent potential targets for myopia therapies. As a first step, this study aimed to characterize the integrin subunits at the messenger RNA level in the sclera of the guinea pig, a more recently added but increasingly used animal model for myopia research.

Methods

Primers for α and β integrin subunits were designed using NCBI/UCSC Genome Browser and Primer3 software tools. Total RNA was extracted from normal scleral tissue and isolated cultured scleral fibroblasts, as well as liver and lung, as reference tissues, all from guinea pig. cDNA was produced by reverse transcription, PCR was used to amplify products of predetermined sizes, and products were sequenced using standard methods.

Results

Guinea pig scleral tissue expressed all known integrin alpha subunits except αD and αE. The latter integrin subunits were also not expressed by cultured guinea pig scleral fibroblasts; however, their expression was confirmed in guinea pig liver. In addition, isolated cultured fibroblasts did not express integrin subunits αL, αM, and αX. This difference between results for cultured cells and intact sclera presumably reflects the presence in the latter of additional cell types. Both guinea pig scleral tissue and isolated scleral fibroblasts expressed all known integrin beta subunits. All results were verified through sequencing.

Conclusion

The possible contributions of integrins to scleral remodeling make them plausible targets for myopia prevention. Data from this study will help guide future ex vivo and in vitro studies directed at understanding the relationship between scleral integrins and ocular growth regulation in the guinea pig model for myopia.
    Cover page: Expression Profile of the Integrin Receptor Subunits in the Guinea Pig Sclera
    • Article
    • Peer Reviewed
    Berkeley Research Impact Initiative (BRII) (2013)

    In human eyes, ocular enlargement/growth reflects active extracellular matrix remodeling of the outer scleral shell. Micro-RNAs are small non-coding RNAs that regulate gene expression by base pairing with target sequences. They serve as nodes of signaling networks. We hypothesized that the sclera, like most tissues, expresses micro-RNAs, some of which modulate genes regulating ocular growth. In this study, the scleral micro-RNA expression profile of rapidly growing human fetal eyes was compared with that of stable adult donor eyes using high-throughput microarray and quantitative PCR analyses.

    Methods:

    Scleral samples from normal human fetal (24 wk) and normal adult donor eyes were obtained (n=4 to 6, each group), and RNA extracted. Genome-wide micro-RNA profiling was performed using the Agilent micro-RNA microarray platform. Micro-RNA target predictions were obtained using Microcosm, TargetScan and PicTar algorithms. TaqMan® micro-RNA assays targeting micro-RNAs showing either highest significance, detection, or fold differences, and collagen specificity, were applied to scleral samples from posterior and peripheral ocular regions (n=7, each group). Microarray data were analyzed using R, and quantitative PCR data with 2^-deltaCt methods.

    Results :

    Human sclera was found to express micro-RNAs, and comparison of microarray results for adult and fetal samples revealed many to be differentially expressed (p<0.01, min p= 6.5x1011). Specifically, fetal sclera showed increased expression of mir-214, let-7c, let-7e, mir-103, mir-107, and mir-98 (1.5 to 4 fold changes, p<0.01). However, no significant regionally specific differences .i.e., posterior vs. peripheral sclera, were observed for either adult or fetal samples.

    Conclusion:

    For the first time, micro-RNA expression has been catalogued in human sclera. Some micro-RNAs show age-related differential regulation, higher in the sclera of rapidly growing fetal eyes, consistent with a role in ocular growth regulation. Thus micro-RNAs represent potential targets for ocular growth manipulation, related to myopia and/or other disorders such as scleral ectasia.

      • Article
      • Peer Reviewed
      UC Berkeley Previously Published Works (2016)

      Purpose

      To evaluate the association between refractive error and the prevalence of glaucoma by race or ethnicity.

      Design

      Cross-sectional study.

      Participants

      Kaiser Permanente Northern California Health Plan members with refractive error measured at 35 years of age or older between 2008 and 2014 and with no history of cataract surgery, refractive surgery, or a corneal disorder.

      Methods

      We identified 34 040 members with glaucoma or ocular hypertension (OHTN; cases) and 403 398 members without glaucoma (controls). Glaucoma cases were classified as primary angle-closure glaucoma (PACG); 1 of the 4 forms of open-angle glaucoma: primary open-angle glaucoma (POAG), normal-tension glaucoma (NTG), pigmentary glaucoma (PIGM), and pseudoexfoliation glaucoma (PEX); or OHTN. Refractive error, expressed as spherical equivalent (SE), was coded as a continuous trait and also as categories. Logistic regression analyses were used to estimate the association between refractive error and the prevalence of glaucoma overall and in specific racial or ethnic groups.

      Main outcome measures

      The association between refractive error and glaucoma subtypes evaluated as odds ratios (ORs) with 95% confidence intervals (CIs).

      Results

      In controls, the mean SE was -0.59 diopters (D) (standard deviation, 2.62 D). Each 1-D reduction in SE was associated with a 22% decrease in the odds of PACG (OR, 0.78; 95% CI, 0.77-0.80) and with increases in the odds of open-angle glaucoma ranging from 1.23 (95% CI, 1.20-1.26) for PIGM, to 1.07 (95% CI, 1.03-1.11) for PEX, and to 1.05 (95% CI, 1.04-1.06) for OHTN. In addition, we observed a stronger association between myopia and POAG among non-Hispanic whites (OR, 1.12; 95% CI, 1.11-1.13) and NTG among Asians (OR, 1.17; 95% CI, 1.15-1.20) and non-Hispanic whites (OR, 1.19; 95% CI, 1.15-1.22).

      Conclusions

      Myopia was associated with an increased prevalence of all forms of open-angle glaucoma and OHTN, whereas hyperopia was associated with a substantially increased prevalence of PACG. Although high myopia is a strong risk factor for glaucoma subtypes, low and moderate myopia also have a significant effect on glaucoma risk. Additionally, there were moderate racial differences in the association of myopia with the risk of POAG and NTG.
        Cover page: The Association of Refractive Error with Glaucoma in a Multiethnic Population
        • Article
        • Peer Reviewed
        UC Berkeley Previously Published Works (2016)

        Purpose

        MicroRNA (miRNAs) have been previously implicated in scleral remodeling in normal eye growth. They have the potential to be therapeutic targets for prevention/retardation of exaggerated eye growth in myopia by modulating scleral matrix remodeling. To explore this potential, genome-wide miRNA and messenger RNA (mRNA) scleral profiles in myopic and control eyes from mice were studied.

        Methods

        C57BL/6J mice (n = 7; P28) reared under a 12L:12D cycle were form-deprived (FD) unilaterally for 2 weeks. Refractive error and axial length changes were measured using photorefraction and 1310-nm spectral-domain optical coherence tomography, respectively. Scleral RNA samples from FD and fellow control eyes were processed for microarray assay. Statistical analyses were performed using National Institute of Aging array analysis tool; group comparisons were made using ANOVA, and gene ontologies were identified using software available on the Web. Findings were confirmed using quantitative PCR in a separate group of mice (n = 7).

        Results

        Form-deprived eyes showed myopic shifts in refractive error (-2.02 ± 0.47 D; P < 0.01). Comparison of the scleral RNA profiles of test eyes with those of control eyes revealed 54 differentially expressed miRNAs and 261 mRNAs fold-change >1.25 (maximum fold change = 1.63 and 2.7 for miRNAs and mRNAs, respectively) (P < 0.05; minimum, P = 0.0001). Significant ontologies showing gene over-representation (P < 0.05) included intermediate filament organization, scaffold protein binding, detection of stimuli, calcium ion, G protein, and phototransduction. Significant differential expression of Let-7a and miR-16-2, and Smok4a, Prph2, and Gnat1 were confirmed.

        Conclusions

        Scleral mi- and mRNAs showed differential expression linked to myopia, supporting the involvement of miRNAs in eye growth regulation. The observed general trend of relatively small fold-changes suggests a tightly controlled, regulatory mechanism for scleral gene expression.
          Cover page: Genome-Wide Scleral Micro- and Messenger-RNA Regulation During Myopia Development in the MouseScleral mi- and mRNA Profiles in Myopia Development
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