Advances in biomedical study of the myopia-related signaling pathways and mechanisms

The interplay between systemic inflammation and myopia: A bidirectional Mendelian randomization and experimental validation study

PURPOSE

Though the pathogenesis of myopia remains unclear, emerging evidence suggests a potential link between the onset of myopia and systemic inflammation. This study aims to elucidate the causal relationships between the two via Mendelian randomization (MR).

METHODS

We utilized genome-wide association study data on circulating inflammatory proteins (n = 14,824), immune cell traits (n = 3757), and myopia (n cases = 4106, n controls = 394,028) for a standard two-sample bidirectional MR analysis, followed by sensitivity analyses employing diverse approaches. The validation of seven inflammatory molecules was conducted through ELISA analysis of 116 plasma samples from a hospital-based cohort, as well as proteomics data from 3310 participants in the UK Biobank cohort.

RESULTS

Our analysis identified three inflammatory proteins (CXCL9, CXCL11, and T cell surface glycoprotein CD5) and six immune phenotypes, primarily related to T cells, as risk factors for myopia, and IL-5 and eight traits as protective factors. Meanwhile, we observed that myopia may elevate the levels of two inflammatory agents (TNFRSF9 and IL-24) and 12 peripheral immunophenotypes, predominantly associated with T cells and monocytes. Validation analysis in two independent cohorts further corroborated the proinflammatory state in highly myopic patients manifested by significantly elevated plasma levels of CXCL9, CXCL11, and TNFRSF9.

CONCLUSIONS

Our study identified a potential bidirectional causal relationship between systemic immune dynamics and myopia, underscoring the importance of considering myopia in the context of systemic condition. Research is warranted to further identify underlying mechanisms.

Visual environmental risk factors in outdoor activities and near work and potential mechanisms

PURPOSE

Myopia is highly prevalent among children and adolescents and results from abnormal refractive development. Less outdoor time as well as more near work have been recognised as major risk factors for myopia. This study analysed the major environmental factors related to myopia, such as outdoor activities and near work, and reviewed the potential mechanisms of myopia development.

METHODS

A systematic search was conducted across PubMed, Web of Science, Cochrane Library and Ovid databases within the last two decades up to November 2024. This review followed the recommendations of the PRISMA Statement and only full-text review articles in English were included.

RESULTS

Summarising the findings from 13 review articles, the environmental risk factors for myopia included lighting features such as low illumination and monochromatic light as well as aspects of the visual scene, for example, the presence of low spatial frequencies and hyperopic defocus. These particular visual stimuli may contribute to the onset and progression of myopia and increase the risk of retinal disorders by reducing choroidal blood flow, leading to scleral hypoxia and remodelling. When analysing environmental risk factors, it is challenging to isolate the individual contributions of outdoor time and near work. Furthermore, previous studies used different definitions of environmental exposures.

CONCLUSIONS

Future research needs quantitative, objective and standardised measures to improve the comparability and consistency between studies. In addition, work should focus on different ethnic populations and gene-environment studies, so as to determine the influence of environmental risk factors on myopia.

The causal impact of gut microbiota and metabolites on myopia and pathological myopia: a mediation Mendelian randomization study

Myopia, a major cause of irreversible visual impairment globally, is projected to affect about 25% of the world's population by 2025. Myopia progresses through childhood and adolescence, necessitating frequent prescription updates. While genetic and environmental factors are well-established contributors to myopia, emerging evidence suggests a significant role of the gut microbiota (GM) in its development, mainly through metabolic interactions. This study utilized a Mendelian Randomization (MR) approach to investigate the causal relationships between GM, metabolites, and myopia and pathological myopia (PM) progression. Using genetic variants as instrumental variables, we analyzed data from extensive genome-wide association studies (GWAS) to assess the impacts of 473 GM taxa and 233 metabolites on myopia risks. Our MR analysis identified specific GM taxa and metabolites with significant causal relationship to myopia and PM. Notably, lipid metabolites were found to mediate the effects of GM on myopia, suggesting a biochemical pathway that could influence ocular development and myopia progression. We also observed significant mediation effects, indicating that specific metabolites might serve as therapeutic targets to modulate myopia progression. The findings highlight the potential of GM and metabolites as novel targets for preventing or managing myopia. This study underscores the importance of further research into the gut-metabolite-eye axis to develop targeted interventions for myopia based on modifying the GM through diet, probiotics, or other means. Future studies should aim to elucidate the specific metabolites involved and their roles in ocular health, potentially offering new avenues for treatment.

Structure/function alterations and related neurotransmitter activity maps in high myopia patients

This study explored the relationship between brain structure and functional pattern as well as the potential neurotransmitter activity alterations in patients with high myopia (HM). Total 33 HM patients and 31 healthy controls were included. Gray matter volume (GMV) was employed to represent brain structure indicator, and amplitude of low-frequency fluctuations (ALFF) was used as an indicator of function. Use the data fusion method of parallel independent component analysis (ICA) to identify the independent components of two patterns and analyze the relationship between them. The spatial correlations between the altered ICA value and neurotransmitter maps were calculated. The results show that there is a significantly related sets of independent components (GMV_IC5 and ALFF_IC4) between the HM and healthy control groups in terms of structure and function. The structural components mainly include the temporal lobe, frontal lobe, cingulate gyrus, and occipital lobe; the functional components are primarily composed of the precuneus, occipital lobe, temporal lobe, and lingual Gyrus. The change value of GMV_IC5 is significantly correlated with serotonin 5-hydroxytryptamine receptor (subtype 1a, 1b and 2a), dopamine D1, gamma-aminobutyric acid (GABAa), and metabotropic glutamate receptor 5; while, the altered ALFF in ALFF_IC4 is significantly correlated with serotonin 5-hydroxytryptamine receptor subtype 2a, dopamine D1, and GABAa. Research results suggest the structural and functional components that change together reflect the association between the visual brain regions and the temporal-frontal areas in HM, as well as their correlation with serotonin receptors, dopamine, and the GABA neurotransmitter system.

PMPred-AE: a computational model for the detection and interpretation of pathological myopia based on artificial intelligence

Introduction

Pathological myopia (PM) is a serious visual impairment that may lead to irreversible visual damage or even blindness. Timely diagnosis and effective management of PM are of great significance. Given the increasing number of myopia cases worldwide, there is an urgent need to develop an automated, accurate, and highly interpretable PM diagnostic technology.

Methods

We proposed a computational model called PMPred-AE based on EfficientNetV2-L with attention mechanism optimization. In addition, Gradient-weighted class activation mapping (Grad-CAM) technology was used to provide an intuitive and visual interpretation for the model's decision-making process.

Results

The experimental results demonstrated that PMPred-AE achieved excellent performance in automatically detecting PM, with accuracies of 98.50, 98.25, and 97.25% in the training, validation, and test datasets, respectively. In addition, PMPred-AE can focus on specific areas of PM image when making detection decisions.

Discussion

The developed PMPred-AE model is capable of reliably providing accurate PM detection. In addition, the Grad-CAM technology was also used to provide an intuitive and visual interpretation for the decision-making process of the model. This approach provides healthcare professionals with an effective tool for interpretable AI decision-making process.

Identifying pathological myopia associated genes with GenePlexus in protein-protein interaction network

Introduction

Pathological myopia, a severe form of myopia, is characterized by an extreme elongation of the eyeball, leading to various vision-threatening complications. It is broadly classified into two primary types: high myopia, which primarily involves an excessive axial length of the eye with potential for reversible vision loss, and degenerative myopia, associated with progressive and irreversible retinal damage.

Methods

Leveraging data from DisGeNET, reporting 184 genes linked to high myopia and 39 genes associated with degenerative myopia, we employed the GenePlexus methodology in conjunction with screening tests to further explore the genetic landscape of pathological myopia.

Results and discussion

Our comprehensive analysis resulted in the discovery of 21 new genes associated with degenerative myopia and 133 genes linked to high myopia with significant confidence. Among these findings, genes such as ADCY4, a regulator of the cAMP pathway, were functionally linked to high myopia, while THBS1, involved in collagen degradation, was closely associated with the pathophysiology of degenerative myopia. These previously unreported genes play crucial roles in the underlying mechanisms of pathological myopia, thereby emphasizing the complexity and multifactorial nature of this condition. The importance of our study resides in the uncovering of new genetic associations with pathological myopia, the provision of potential biomarkers for early screening, and the identification of therapeutic targets.

Understanding cataract development in axial myopia: The contribution of oxidative stress and related pathways

Myopia is an evolving global health challenge, with estimates suggesting that by 2050 it will affect half of the world's population, becoming the leading cause of irreversible vision loss. Moreover, myopia can lead to various complications, including the earlier onset of cataracts. Given the progressive aging of the population and the increase in life expectancy, this will contribute to a rising demand for cataract surgery, posing an additional challenge for healthcare systems. The pathogenesis of nuclear and posterior subcapsular cataract (PSC) development in axial myopia is complex and primarily involves intensified liquefaction of the vitreous body, excessive production of reactive oxygen species, impaired antioxidant defense, and chronic inflammation in the eyeball. These factors contribute to disruptions in mitochondrial homeostasis, abnormal cell signaling, lipid peroxidation, protein and nucleic acid damage, as well as the induction of adverse epigenetic modifications. Age-related and oxidative processes can cause destabilization of crystallins with subsequent protein accumulation, which finally drives to a lens opacification. Moreover, an altered redox status is one of the major contributors to the pathogenesis of PSC. This review aims to summarize the mechanisms known to be responsible for the accelerated development of cataracts in axial myopia and to enhance understanding of these relationships.

Exploring Molecular Pathways in Refractive Errors Associated with Inherited Retinal Dystrophies

The term inherited retinal dystrophies (IRDs) refers to a diverse range of conditions characterized by retinal dysfunction, and mostly deterioration, leading to a gradual decay of the visual function and eventually to total vision loss. IRDs have a global impact on about 1 in every 3000 to 4000 individuals. However, the prevalence statistics might differ significantly depending on the exact type of dystrophy and the demographic being examined. The cellular pathophysiology and genetic foundation of IRDs have been extensively studied, however, knowledge regarding associated refractive errors remain limited. This review aims to clarify the cellular and molecular processes that underlie refractive errors in IRDs. We did a thorough search of the current literature (Pubmed, accession Feb 2024), selecting works describing phenotypic differences among genes-related to IRDs, particularly in relation to refractive errors. First, we summarize the wide range of IRDs and their genetic causes, describing the genes and biological pathways connected to the etiology of the disease. We then explore the complex relationship between refractive errors and retinal dysfunction, including how the impairment of the vision-related mechanisms in the retina can affect ocular biometry and optical characteristics. New data about the involvement of aberrant signaling pathways, photoreceptor degeneration, and dysfunctional retinal pigment epithelium (RPE) in the development of refractive errors in IRDs have been examined. We also discuss the therapeutic implications of refractive defects in individuals with IRD, including possible approaches to treating visual impairments. In addition, we address the value of using cutting-edge imaging methods and animal models to examine refractive errors linked to IRDs and suggest future lines of inquiry for identifying new targets for treatment. In summary, this study presents an integrated understanding of the cellular and molecular mechanisms underlying refractive errors in IRDs. It illuminates the intricacies of ocular phenotypes in these conditions and offers a tool for understanding mechanisms underlying isolated refractive errors, besides the IRD-related forms.

Electroacupuncture alleviates damage to myopic RGCs probably through lncRNA-XR_002789763.1-mediated mitophagy

BACKGROUND

Mitophagy is closely related to the regulation of retinal ganglion cell (RGC) structure and function. Our previous study suggested that long noncoding RNAs (lncRNAs) can cause damage to myopic RGCs. However, whether electroacupuncture (EA) treatment can delay myopia progression through lncRNA-mediated mitophagy in RGCs is currently unknown. This study aimed to investigate the effect of EA on lncRNA-mediated mitophagy in myopic RGCs.

METHODS

Our study investigated the modulatory effect of EA on mitophagy in RGCs of guinea pigs with form-deprived myopia (FDM). RNA sequencing was performed to further analyze the expression profiles of lncRNAs and mRNAs in RGCs of guinea pigs with FDM after EA treatment, and the related competing endogenous RNA (ceRNA) network was constructed. Importantly, PINK1, a mitophagy-related gene, was included in the core ceRNA network to explore the relationship between lncRNAs and mitophagy in myopic RGCs regulated by EA. We also collected eyeballs from myopic and highly myopic adults to further verify the mechanistic results.

RESULTS

This study demonstrated that EA treatment delayed the reduction in refraction and increase in axial length and alleviated RGC damage in guinea pigs with FDM. We further found that EA could induce mitophagy in guinea pig RGCs with FDM by promoting the mitophagy-related PINK1/Parkin signaling pathway. Moreover, mitophagy is inhibited in the retina of highly myopic adults. RNA sequencing revealed that 599 lncRNAs and 455 mRNAs were differentially expressed in guinea pig RGCs with FDM after EA treatment. A core ceRNA network was constructed by incorporating PINK1 and verified by related molecular experiments, and we found that EA treatment may induce mitophagy and attenuated RGC injury in guinea pigs with FDM by sponging miR-342-5p through lncRNA-XR_002789763.1 to activate the PINK1/Parkin signaling pathway and promote Mfn2 ubiquitination.

CONCLUSION

EA treatment might regulate lncRNA-XR_002789763.1/miR-342-5p axis and activate the mitophagy-related PINK1/Parkin signaling pathway, and promote Mfn2 ubiquitination, thereby alleviating RGC damage and delaying myopia progression.

UPLC-MS/MS-based serum metabolomics analysis for comprehensive pathological myopia profiling

Pathological myopia (PM) is associated with ocular morbidities that cause blindness. PM often occurs in eyes with high myopia (HM) while they are distinctly different. Identifying the differences in metabolites and metabolic pathways between patients with PM and HM may provide information about the pathogenesis of PM, which is currently unknown. This study aimed to reveal the comprehensive metabolic alterations associated with PM. Thirty patients with PM, 27 with simple HM and 27 with low myopia (LM) were enrolled in this study. Ultra-performance liquid chromatography/tandem mass spectrometry (UPLC-MS/MS) was performed, and a Venn diagram was generated to explore the overlapping differential metabolites and enriched pathways between each set of two groups. The area under the receiver operating characteristic curve (AUC) was computed to assess the discrimination capacity of each metabolite marker. A total of 134, 125 and 81 differential metabolites were identified in each comparison. Thirty-two differential metabolites were overlapped between the PM vs HM comparison and the PM vs LM comparison. Of these 32 metabolites, 16 were common to all three comparisons; among these metabolites, high levels of 4-hydroxy-l-glutamic acid and low levels of succinic semialdehyde and 2,3-dinor-8-iso prostaglandin F2α appeared to be risk factors for PM. The remaining 16 metabolites were shared only between the PM versus HM and PM versus LM comparisons, most of which are lipid molecules. Pathway analysis revealed that alanine, aspartate and glutamate metabolism was the key metabolic pathway altered in PM patients. Overall, significant differences in the metabolites and metabolic pathways were observed in patients with PM. The metabolic differences identified in this study included differential factors between PM and HM patients, addressing current gaps in PM research. These findings provide a novel perspective of the molecular mechanism of PM.

A study on the variability and correlation of ocular biological measurement parameters in adult myopic patients

Objective

This study aims to explore the differences in ocular parameters among adult myopic patients with different degrees of myopia and axial lengths, and to investigate the correlations between these ocular parameters.

Methods

This single-center observational study collected clinical data from myopic patients aged 18-45 years who visited the Eye Hospital of Nanjing Medical University between January and June 2023. The data included laterality, diopter of spherical power (DS), diopter of cylindrical power (DC), spherical equivalent (SE), axial length (AL), central corneal thickness (CCT), flat meridian keratometry (K1), steep meridian keratometry (K2), mean keratometry (Km), anterior chamber depth (ACD), corneal radius of curvature (CRC), and axial length/corneal radius of curvature ratio (AL/CRC). Following predefined inclusion and exclusion criteria, 1,026 eyes were included in the study. Patients were grouped based on SE and AL parameters into different degrees of myopia. Analysis of variance (ANOVA) and Welch ANOVA were used to compare intergroup differences. Spearman correlation coefficients were calculated to analyze the correlations between parameters, and linear regression and ROC curve analyses were performed.

Results

Significant differences (p < 0.05) were found among mild, moderate, and high myopia groups in parameters such as DS, DC, AL, K1, Km, ACD, CRC, and AL/CRC. Significant differences (p < 0.05) were also found in DS, DC, SE, CCT, K1, K2, Km, ACD, CRC, and AL/CRC among different axial length groups. Spearman correlation analysis showed a strong correlation between AL and DS, SE, and between AL/CRC and DS, SE, AL. Linear regression analysis revealed that the coefficient of determination (R2) for AL and SE was 0.699, and for AL/CRC and SE, it was 0.861. ROC curve analysis demonstrated high accuracy for both AL and AL/CRC in identifying high myopia, with an AUC of 0.952 for AL/CRC, which was superior to the AUC of 0.905 for AL (p < 0.05).

Conclusion

This study found significant differences in ocular parameters among patients with different degrees of myopia and axial lengths. There was a significant negative correlation between AL, AL/CRC, and SE. Compared to AL, AL/CRC had a stronger correlation with SE and higher accuracy in identifying high myopia.

An Evidence-Based Narrative Review of Scleral Hypoxia Theory in Myopia: From Mechanisms to Treatments

Myopia is one of the dominant causes of visual impairment in the world. Pathological myopia could even lead to other serious eye diseases. Researchers have reached a consensus that myopia could be caused by both environmental and genetic risk factors. Exploring the pathological mechanism of myopia can provide a scientific basis for developing measures to delay the progression of myopia or even treat it. Recent advances highlight that scleral hypoxia could be an important factor in promoting myopia. In this review, we summarized the role of scleral hypoxia in the pathology of myopia and also provided interventions for myopia that target scleral hypoxia directly or indirectly. We hope this review will aid in the development of novel therapeutic strategies and drugs for myopia.

Compartmental analysis of retinal vascular parameters and thickness in myopic eyes using SS-OCTA

Background

This study aimed to comprehensively explore the thickness and topographic distributions of retinal vessel alterations of different myopic eyes by using swept-source OCT angiography (SS-OCTA).

Methods

One hundred myopes were included in this observational cross-sectional study. All participants underwent a series of ocular examinations of biometrical parameters, including spherical equivalent refraction (SER), axial length (AL), intraocular pressure (IOP), curvature radius (CR), and others. Retinal parameters like vessel density (VD) of different compartments of papillary and peripapillary sectors were measured by SS-OCTA, respectively. Two sample-independent T-test was applied to identify intraocular differences in retinal biometrical indicators between groups, and correlation analysis was used to explore potential relationships between AL/CR ratio and some ocular variables.

Results

For high myopic participants, they exhibited a lower vessel density, a lower small vessel density, and a lower flow area, especially in the superficial layer and the nerve fiber layer (RNFL), along with a thinner superficial layer, RNFL and retina. More alterations were proved in nasal peripapillary sectors in high myopes. We also explored their hidden relationship with AL/CR ratio. We found that in non-high myopes, the thickness of the whole retina, RNFL and the superficial layer were all negatively correlated with AL/CR ratio in the papillary and peripapillary zone. In contrast, the vessel density and flow area of several vessel layers were positively correlated. However, there wasn't so much significance found in high myopic eyes.

Conclusion

Retinal vessel microstructure was more easily affected in highly myopic eyes, especially in superficial blood vessels, and compartmental analysis showed that alterations in nasal peripapillary sectors were more evident. Additionally, we highlighted hidden correlations between AL/CR ratio and blood flow characteristics of specific vascular layers, which could serve as sensitive biometrical indicators of early retinal damages.

Protective effects of docosahexaenoic acid combined with bilberry extract on myopic Guinea pigs

This study aims to investigate the protective effects of docosahexaenoic acid (DHA) combined with bilberry extract (BE) on myopic guinea pigs. In total, 105 healthy pigmented guinea pigs aged 2 weeks were selected and randomly divided into five groups. The normal control (NC) group received no treatment, while the experimental groups wore -6.0D lenses on the right eye to establish an animal model of lens-induced myopia (LIM). These groups were further divided based on different treatments: normal feeding, DHA treatment, BE treatment, and combined DHA + BE treatment. Refractive error and axial length for both eyes were measured before modeling, after 4 weeks of modeling, and after 8 weeks of treatment. Fundus examination was performed, and choroidal thickness, choroidal vascularity index (CVI), maximal mixed response in dark adaptation (Max-ERG), and cone cell response in light adaptation (Cone-ERG) were measured. After 8 weeks of treatment, we observed a significant reduction in refractive error and shortening of axial length, improvement in fundus condition, and increased choroidal thickness and CVI in the LIM + DHA + BE group. Electroretinogram (ERG) showed that the amplitudes of a-wave and b-wave were enhanced in both Max-ERG and Cone-ERG tests. The LIM + DHA + BE group exhibited superior effects compared to the LIM + DHA group and the LIM + BE group. The combination of DHA and BE delayed the progression of LIM in guinea pigs and was more effective than DHA or BE alone. The synergistic effect of DHA and BE offers a new approach to the prevention and treatment of myopia.

Impact of red and blue monochromatic light on the visual system and dopamine pathways in juvenile zebrafish

BACKGROUND

The development of the zebrafish visual system is significantly influenced by exposure to monochromatic light, yet investigations into its effects during juvenile stages are lacking. This study evaluated the impacts of varying intensities and durations of red and blue monochromatic light on the visual system and dopamine pathways in juvenile zebrafish.

METHODS

Juvenile zebrafish were exposed to red (650 nm) and blue (440 nm, 460 nm) monochromatic lights over four days at intensities ranging from 500 to 10,000 lx, for durations of 6, 10, and 14 h daily. A control group was maintained under standard laboratory conditions. Post-exposure assessments included the optokinetic response (OKR), retinal structural analysis, ocular dopamine levels, and the expression of genes related to dopamine pathways (Th, Dat, and Mao).

RESULTS

(1) OKR enhancement was observed with increased 440 nm light intensity, while 460 nm and 650 nm light exposures showed initial improvements followed by declines at higher intensities. (2) Retinal thinning in the outer nuclear layer was observed under the most intense (10,000 lx for 14 h) light conditions in the 440 nm and 650 nm groups, while the 460 nm group remained unaffected. (3) Dopamine levels increased with higher intensities in the 440 nm group, whereas the 460 nm group exhibited initial increases followed by decreases. The 650 nm group displayed similar trends but were statistically insignificant compared to the control group. (4) Th expression increased with light intensity in the 440 nm group. Dat showed a rising and then declining pattern, and Mao expression significantly decreased. The 460 nm group exhibited similar patterns for Th and Dat to the behavioral observations, but an inverse pattern for Mao. The 650 nm group presented significant fluctuations in Th and Dat expressions, with pronounced variations in Mao.

CONCLUSIONS

Specific red and blue monochromatic light conditions promote visual system development in juvenile zebrafish. However, exceeding these optimal conditions may impair visual function, highlighting the critical role of dopamine pathway in modulating light-induced effects on the visual system.

Lifelong Changes in the Choroidal Thickness, Refractive Status, and Ocular Dimensions in C57BL/6J Mouse

Purpose

To investigate the changes in choroidal thickness (ChT), refractive status, and ocular dimensions in the mouse eye in vivo using updated techniques and instrumentation.

Methods

High-resolution swept-source optical coherence tomography (SS-OCT), eccentric infrared photoretinoscopy, and custom real-time optical coherence tomography were used to analyze choroidal changes, refractive changes and ocular growth in C57BL/6J mice from postnatal day (P) 21 to month 22.

Results

The ChT gradually increased with age, with the thickest region in the para-optic nerve head and thinning outward, and the temporal ChT was globally thicker than the nasal ChT. Retinal thickness remained stable until 4 months and subsequently decreased. The average spherical equivalent refraction error was -4.81 ± 2.71 diopters (D) at P21, which developed into emmetropia by P32, reached a hyperopic peak (+5.75 ± 1.38 D) at P82 and returned to +0.66 ± 1.86 D at 22 months. Central corneal thickness, anterior chamber depth, lens thickness, and axial length (AL) increased continuously before 4 months, but subsequently exhibited subtle changes. Vitreous chamber depth decreased with lens growth. ChT was correlated significantly with the ocular parameters (except for retinal thickness) before the age of 4 months, but these correlations diminished after 4 months. Furthermore, for mice younger than 4 months, the difference in the ChT, especially temporal ChT, between the two eyes contributed most to that of axial length and spherical equivalent refraction error.

Conclusions

Four months could be a watershed age in the growth of mouse eyes. Large-span temporal recordings of refraction, ocular dimensions, and choroidal changes provided references for the study of the physiological and pathological mechanisms responsible for myopia.

Research Progress on the Role of Ubiquitination in Eye Diseases

The occurrence and development of ophthalmic diseases are related to the dysfunction of eye tissues. Ubiquitin is an important form of protein post-translational modification, which plays an essential role in the occurrence and development of diseases through specific modification of target proteins. Ubiquitination governs a variety of intracellular signal transduction processes, including proteasome degradation, DNA damage repair, and cell cycle progression. Studies have found that ubiquitin can play a role in eye diseases such as cataracts, glaucoma, keratopathy, retinopathy, and eye tumors. In this paper, the role of protein ubiquitination in eye diseases was reviewed.

Mediation effect of sleep time on the association between outdoor activity and myopia in Chinese children and adolescents: a cross-sectional study

BACKGROUND

This study aimed to assess the association between outdoor activity and myopia among children and adolescents and investigate whether sleep time could mediate this relationship.

METHODS

This cross-sectional study was performed on students aged 4-16 years in China, from August 2021 to January 2022. Outdoor activity was assessed by the Assessment Questionnaire of Exposure to Sunlight Activities for Students (AQESAS). Binary logistic regression combined with the mediation analysis was used to analyze the association of AQESAS with myopia and the mediating effect of sleep time on this relationship.

RESULTS

The prevalence of myopia was 53.51% (N = 1609). Multivariate logistic regression analysis showed that more sleep time (OR = 0.794, 95%CI: 0.707-0.893) and a higher score of AQESAS (OR = 0.989, 95%CI: 0.981-0.996) were significantly associated with a decreased risk of myopia. Mediation analysis revealed that sleep time plays a mediating role in the association between outdoor activity and myopia (ACME = -0.0006, P < 0.001), and the mediation proportion was 19.7%.

CONCLUSION

Outdoor activity affects myopia directly and indirectly through sleep time. The result suggested that children may be able to reduce the risk of myopia by promoting sleep through increased awareness of outdoor activity and exposure to sunlight.

Unmasking of molecular players: proteomic profiling of vitreous humor in pathologic myopia

BACKGROUND

This study aimed to identify the differentially expressed proteins in the vitreous humor (VH) of eyes with and without pathologic myopia (PM), providing insights into the molecular pathogenesis.

METHODS

A cross-sectional, observational study was conducted. VH samples were collected from patients undergoing vitrectomy for idiopathic epiretinal membrane (ERM), macular hole (MH), or myopic retinoschisis (MRS). Label-free quantitative proteomic analysis identified differential protein expression, with validation using ELISA.

RESULTS

The proteomic profiling revealed significantly higher expressions of tubulin alpha 1a (TUBA1A) and eukaryotic translation elongation factor 1 alpha 1 (EEF1A1) in PM groups (MH-PM, MRS-PM) compared to controls (MH, ERM). Conversely, xylosyltransferase 1 (XYLT1), versican core protein (VCAN), and testican-2 (SPOCK2) expressions were lower in PM. ELISA validation confirmed these findings.

CONCLUSIONS

Our study provides novel insights into the molecular mechanisms of PM. The differentially expressed proteins EEF1A1, TUBA1A, XYLT1, VCAN, and SPOCK2 may play crucial roles in chorioretinal cell apoptosis, scleral extracellular matrix (ECM) synthesis, and scleral remodeling in PM. These proteins represent potential new targets for therapeutic intervention in PM, highlighting the importance of further investigations to elucidate their functions and underlying mechanisms in disease pathogenesis.

Adaptive Changes in Neurovascular Properties With Binocular Accommodation Functions in Myopic Participants by 3D Visual Training: An EEG and fNIRS Study

Although three-dimensional visual training (3DVT) has been used for myopia intervention, its neural mechanisms remain largely unknown. In this study, visual function was examined before and after 3DVT, while resting-state EEG-fNIRS signals were recorded from 38 myopic participants. A graph theoretical analysis was applied to compute the neurovascular properties, including static brain networks (SBNs), dynamic brain networks (DBNs), and dynamic neurovascular coupling (DNC). Correlations between the changes in neurovascular properties and the changes in visual functions were calculated. After 3DVT, the local efficiency and node efficiency in the frontal lobes increased in the SBNs constructed from EEG δ -band; the global efficiency and node efficiency in the frontal-parietal lobes decreased in the DBNs variability constructed from EEG δ -band. For the DNC constructed with EEG α -band and oxyhemoglobin (HbO), the local efficiency decreased, for EEG α -band and deoxyhemoglobin (HbR), the node efficiency in the frontal-occipital lobes decreased. For the SBNs constructed from HbO, the functional connectivity (FC) between the frontal-occipital lobes increased. The DNC constructed between the FC of the frontal-parietal lobes from EEG β -band and the FC of the frontal-occipital lobes from HbO increased, and between the FC of the frontal-occipital lobes from EEG β -band and the FC of the inter-frontal lobes from HbR increased. The neurovascular properties were significantly correlated with the amplitude of accommodation and accommodative facility. The result indicated the positive effects of 3DVT on myopic participants, including improved efficiency of brain networks, increased FC of SBNs and DNC, and enhanced binocular accommodation functions.

Choroidal thinning in myopia is associated with axial elongation and severity of myopic maculopathy

High myopia can lead to pathologic myopia and visual impairment, whereas its causes are unclear. We retrospectively researched high myopia cases from patient records to investigate the association between axial elongation and myopic maculopathy. Sixty-four eyes were examined in patients who visited the department between July 2017 and June 2018, had an axial length of 26 mm or more, underwent fundus photography, and had their axial length measured twice or more. The average axial length was 28.29 ± 1.69 mm (mean ± standard deviation). The average age was 58.3 ± 14.4 years old. Myopic maculopathy was categorized as mild (grades 0 and 1) and severe (grades 2, 3, and 4). The severe group had longer axial lengths than the mild group (P < 0.05). Moreover, the severe group exhibited thinner choroidal thickness than the mild group (P < 0.05). When subjects were grouped by axial elongation over median value within a year, the elongation group showed thinner central choroidal thickness than the non-elongation group (142.1 ± 91.9 vs. 82.9 ± 69.8, P < 0.05). In conclusion, in patients with high myopia, the severity of maculopathy correlated with choroidal thickness and axial length. Thinner choroidal thickness was associated with axial elongation based on the baseline axial length.

Enhanced ophthalmic bioavailability and stability of atropine sulfate via sustained release particles using polystyrene sulfonate resin

Atropine sulfate (ATS) eye drops at low concentrations constitute a limited selection for myopia treatment, with challenges such as low ophthalmic bioavailability and inadequate stability. This study proposes a novel strategy by synthesizing ophthalmic sodium polystyrene sulfonate resin (SPSR) characterized by a spherical shape and uniform size for cationic exchange with ATS. The formulation of ATS@SPSR suspension eye drops incorporates xanthan gum and hydroxypropyl methylcellulose (HPMC) as suspending agents. In vitro studies demonstrated that ATS@SPSR suspension eye drops exhibited sustained release characteristics, and tropic acid, its degradation product, remained undetected for 30 days at 40 °C. The ATS levels in the tear fluids and aqueous humor of New Zealand rabbits indicated a significant increase in mean residence time (MRT) and area under the drug concentration-time curve (AUC0-12h) for ATS@SPSR suspension eye drops compared to conventional ATS eye drops. Moreover, safety assessment confirmed the non-irritating nature of ATS@SPSR suspension eye drops in rabbit eyes. In conclusion, the cation-responsive sustained-release ATS@SPSR suspension eye drops enhanced the bioavailability and stability of ATS, offering a promising avenue for myopia treatment.

The association between screen time exposure and myopia in children and adolescents: a meta-analysis

OBJECTIVE

This study aimed to systematically review epidemiological evidence on associations between screen time exposure and myopia in children and adolescents, and to quantitatively evaluate summary effect estimates from existing literature.

METHOD

There were three online databases including PubMed, Embase, and Web of Science, for epidemiological studies on screen time exposure and myopia published before June 1, 2023. The risk of bias was assessed by the Newcastle Ottawa Scale (NOS) checklist. Summary odds ratios (ORs) and 95% confidence intervals (CIs) were calculated to evaluate the correlation between screen time exposure and myopia using random or fixed-effect models by exposure type (categorical/continuous). We also performed subgroup analysis by screen device type, study quality, geographic region, and research period.

RESULTS

We searched 7,571 records from three databases and identified 19 eligible studies, including 14 high-quality studies and 5 moderate-quality studies. Meta-analyses suggested that there was a statistically significant correlation between screen time (high vs. low) and myopia. The pooled ORs with 95%CIs were respectively 2.24 (1.47-3.42) for cross-sectional studies, and 2.39 (2.07-2.76) for cohort studies. We also found a significant association between continuous exposure to screen time (per 1 h/d increase) and myopia in cohort studies. The pooled ORs with 95%CIs were 1.07 (1.01-1.13). In subgroup analysis stratified by screen device type in cross-sectional studies, screen time exposures from computers (categorical: OR = 8.19, 95%CI: 4.78-14.04; continuous: OR = 1.22, 95%CI: 1.10-1.35) and televisions (categorical: OR = 1.46, 95%CI: 1.02-2.10) were associated with myopia, while smartphones were not. Although publication bias was detected, the pooled results did not show significant changes after adjustment using the trim and fill method.

CONCLUSION

Our findings support that screen time exposure was significantly associated with myopia in children and adolescents. Notably, screen time exposure from computers may have the most significant impact on myopia.

Glutathione and a Pool of Metabolites Partly Related to Oxidative Stress Are Associated with Low and High Myopia in an Altered Bioenergetic Environment

Oxidative stress forms part of the molecular basis contributing to the development and manifestation of myopia, a refractive error with associated pathology that is increasingly prevalent worldwide and that subsequently leads to an upsurge in degenerative visual impairment due to conditions that are especially associated with high myopia. The purpose of our study was to examine the interrelation of potential oxidative-stress-related metabolites found in the aqueous humor of high-myopic, low-myopic, and non-myopic patients within a clinical study. We conducted a cross-sectional study, selecting two sets of patients undergoing cataract surgery. The first set, which was used to analyze metabolites through an NMR assay, comprised 116 patients. A total of 59 metabolites were assigned and quantified. The PLS-DA score plot clearly showed a separation with minimal overlap between the HM and control samples. The PLS-DA model allowed us to determine 31 major metabolite differences in the aqueous humor of the study groups. Complementary statistical analysis of the data allowed us to determine six metabolites that presented significant differences among the experimental groups (p < 005). A significant number of these metabolites were discovered to have a direct or indirect connection to oxidative stress linked with conditions of myopic eyes. Notably, we identified metabolites associated with bioenergetic pathways and metabolites that have undergone methylation, along with choline and its derivatives. The second set consisted of 73 patients who underwent a glutathione assay. Here, we showed significant variations in both reduced and oxidized glutathione in aqueous humor among all patient groups (p < 0.01) for the first time. Axial length, refractive status, and complete ophthalmologic examination were also recorded, and interrelations among metabolic and clinical parameters were evaluated.

Ciliary muscles contraction leads to axial length extension--The possible initiating factor for myopia

PURPOSE

This study aimed to investigate the underlying factors driving the onset of myopia, specifically the role of the ciliary muscle's contraction in the elongation of the axial length of the eye.

METHODS

The retrospective study was conducted utilizing data from three ophthalmic centers in Shanghai and Beijing. Both Chinese and Caucasian children were involved. The axial length of the subjects' eyes was measured in both relaxed and contracted state of the ciliary muscle. A comprehensive mechanical model was also developed to observe the influence of ciliary muscle contraction on the axial length.

RESULTS

This study included a sample of 198 right eyes of 198 myopic children. Of these, 97 were male and 101 were female, 126 were of Chinese ethnicity and 72 were Caucasian. The age of onset for myopia ranged from 5.9 to 16.9 years old. The axial length of the eye decreased 0.028 ± 0.007mm following dilation, indicating relaxation of the ciliary muscle (t paired student = 15.16, p = 6.72 x 10-35). In contrast, ciliary muscle contraction resulted in an increase in axial length. Considering proportionality, a significant 90.4% (179 eyes) exhibited a reduced axial length, while a minor 9.6% (19 eyes) demonstrated an increase post-mydriasis. Finite element modeling demonstrated that muscle contraction caused a tension force that transmits towards the posterior pole of the eye, causing it to extend posteriorly.

CONCLUSION

The contraction of the ciliary muscle leads to an extension of the axial length. This could potentially be the initiating factor for myopia.

CircRNA expression profiles and regulatory networks in the vitreous humor of people with high myopia

Myopia is a global health and economic issue. Circular RNAs (circRNAs) have been shown to play an important role in the pathogenesis of many ocular diseases. We first evaluated the circRNA profiles and possible roles in vitreous humor samples of individuals with high myopia by a competitive endogenous RNA (ceRNA) array. Vitreous humor samples were collected from 15 high myopic (5 for ceRNA array, and 10 for qPCR) and 15 control eyes (5 for ceRNA array, and 10 for qPCR) with idiopathic epiretinal membrane (ERM) and macular hole (MH). 486 circRNAs (339 upregulated and 147 downregulated) and 264 mRNAs (202 upregulated and 62 downregulated) were differentially expressed between the high myopia and control groups. The expression of hsa_circ_0033079 (hsa-circDicer1), hsa_circ_0029989 (hsa-circNbea), hsa_circ_0019072 (hsa-circPank1) and hsa_circ_0089716 (hsa-circEhmt1) were validated by qPCR. Pearson analysis and multivariate regression analysis showed positive and significant correlations for axial length with hsa-circNbea and hsa-circPank1. KEGG analysis showed that the target genes of circRNAs were enriched in the mTOR, insulin, cAMP, and VEGF signaling pathways. GO analysis indicated that circRNAs mainly targeted transcription, cytoplasm, and protein binding. CircRNA-associated ceRNA network analysis and PPI network analysis identified several critical genes for myopia. The expression of circNbea, circPank1, miR-145-5p, miR-204-5p, Nras, Itpr1 were validated by qPCR in the sclera of form-deprivation myopia (FDM) mice model. CircPank1/miR-145-5p/NRAS and circNbea/miR-204-5p/ITPR1 were identified and may be important in the progression of myopia. Our findings suggest that circRNAs may contribute to the pathogenesis of myopia and may serve as potential biomarkers.

The role of oxidative stress in the pathogenesis of ocular diseases: an overview

Dysregulation of oxidative stress serves as a pivotal predisposing or exacerbating factor in the intricate development of numerous pathological processes and diseases. In recent years, substantial evidence has illuminated the crucial role of reactive oxygen species (ROS) in many fundamental cellular functions, including proliferation, inflammation, apoptosis, and gene expression. Notably, producing free radicals within ROS profoundly impacts a wide range of biomolecules, such as proteins and DNA, instigating cellular damage and impairing vital cellular functions. Consequently, oxidative stress emerges as a closely intertwined factor across diverse disease spectra. Remarkably, the pathogenesis of several eye diseases, including age-related macular degeneration, glaucoma, and diabetic retinopathy, manifests an intrinsic association with oxidative stress. In this comprehensive review, we briefly summarize the recent progress in elucidating the intricate role of oxidative stress in the development of ophthalmic diseases, shedding light on potential therapeutic avenues and future research directions.

Targeting scleral remodeling and myopia development in form deprivation myopia through inhibition of EFEMP1 expression

The role of extracellular matrix (ECM) remodeling in the axial elongation associated with myopia has not been fully elucidated, although it is considered a significant factor. EFEMP1, a regulator of ECM, has been associated with various pathological conditions. This study aimed to examine the involvement of EFEMP1 in scleral remodeling during form deprivation myopia. The results indicate a progressive increase in EFEMP1 expression following prolonged form deprivation treatment, followed by a subsequent decrease upon recovery. To gain a deeper understanding of the mechanism of EFEMP1, we conducted transcriptome sequencing on primary scleral fibroblasts that were subjected to lentivirus-mediated overexpression of EFEMP1. Validation was performed using lentivirus-induced overexpression and shRNA targeting EFEMP1 in combination with LY294002, a PI3K inhibitor. Our findings suggest that EFEMP1 may be involved in the development of FDM by regulating the expression of the PI3K/AKT/MMP2 axis. The AAV-mediated injection of shEFEMP1 under Tenon's capsule in guinea pigs was observed to effectively delay the progression of myopia and posterior scleral remodeling. In contrast, the AAV-mediated overexpression of EFEMP1 exacerbated the development of myopia and resulted in further thinning of collagen fibers in the posterior sclera. In summary, adjusting EFEMP1 concentrations could potentially serve as a viable approach to prevent and treat myopia by influencing the remodeling process of the posterior sclera.

Circadian rhythm, ipRGCs, and dopamine signalling in myopia

Myopia, a common ophthalmic disorder, places a high economic burden on individuals and society. Genetic and environmental factors influence myopia progression; however, the underlying mechanisms remain unelucidated. This paper reviews recent advances in circadian rhythm, intrinsically photosensitive retinal ganglion cells (ipRGCs), and dopamine (DA) signalling in myopia and proposes the hypothesis of a circadian rhythm brain retinal circuit in myopia progression. The search of relevant English articles was conducted in the PubMed databases until June 2023. Based on the search, emerging evidence indicated that circadian rhythm was associated with myopia, including circadian genes Bmal1, Cycle, and Per. In both humans and animals, the ocular morphology and physiology show rhythmic oscillations. Theoretically, such ocular rhythms are regulated locally and indirectly via the suprachiasmatic nucleus, which receives signal from the ipRGCs. Compared with the conventional retinal ganglion cells, ipRGCs can sense the presence of light because of specific expression of melanopsin. Light, together with ipRGCs and DA signalling, plays a crucial role in both circadian rhythm and myopia. In summary, regarding myopia progression, a circadian rhythm brain retinal circuit involving ipRGCs and DA signalling has not been well established. However, based on the relationship between circadian rhythm, ipRGCs, and DA signalling in myopia, we hypothesised a circadian rhythm brain retinal circuit.

Effects on radius of curvature and refractive power of the cornea and crystalline lens by atropine 0.01% eye drops

PURPOSE

The morphological changes in the cornea and crystalline lens have not been closely evaluated after the administration of atropine 0.01%. This study aims to evaluate the radii of curvature and refractive power of the cornea and lens in myopic eyes during atropine 0.01% treatment.

METHODS

Children aged 6-14 years with myopia <-6.0 D were randomized to receive atropine 0.01% once nightly with single vision lenses or simply wear single vision lenses. Ocular biometric parameters were measured using the IOLMaster 700 biometry and the radii of corneal and lenticular curvature were simulated using a customized program.

RESULTS

At the 9-month visit, 69 atropine-treated eyes and 50 control eyes were included in the final analyses. In atropine-treated eyes, the posterior corneal surface steepened (-0.05 ± 0.13 mm) and the anterior lenticular surface flattened (0.20 ± 0.69 mm) significantly within 3-6 months, whereas the posterior corneal surface and anterior lenticular surface gradually flattened (0.07 ± 0.23 and 0.32 ± 0.80 mm respectively) in the control eyes over 9 months. The difference in the change of corneal refractive power was significant between groups (-0.03 ± 0.18 D vs. 0.11 ± 0.24 D, p = 0.001), while that in the change of lenticular refractive power was statistically insignificant (0.01 ± 0.92 D vs. -0.22 ± 0.86 D, p = 0.161).

CONCLUSIONS

The administration of atropine 0.01% exhibited a clinically short and subtle impact on the cornea and lens, which may shed light on new targets of action for atropine in inhibiting myopia.

Dynamic changes in ocular shape during human development and its implications for retina fovea formation

The human fovea is known for its distinctive pit-like appearance, which results from the displacement of retinal layers superficial to the photoreceptors cells. The photoreceptors are found at high density within the foveal region but not the surrounding retina. Efforts to elucidate the mechanisms responsible for these unique features have ruled out cell death as an explanation for pit formation and changes in cell proliferation as the cause of increased photoreceptor density. These findings have led to speculation that mechanical forces acting within and on the retina during development underly the formation of foveal architecture. Here we review eye morphogenesis and retinal remodeling in human embryonic development. Our meta-analysis of the literature suggests that fovea formation is a protracted process involving dynamic changes in ocular shape that start early and continue throughout most of human embryonic development. From these observations, we propose a new model for fovea development.

Kinematic characteristics of gait with different myopia: a cross-sectional study

Background

Myopia, a condition affecting approximately one-quarter of the world' s population, has been projected to double in prevalence by the year 2050. It can have an impact on postural control during walking and can increase the risk of falls and injuries.

Objective

(1) To examine the abnormal performance of postural control during walking in male college students who used convex lenses for myopia intervention from a kinematic perspective; (2) to establish theoretical foundation for preventing falls and injuries in the myopic population.

Methods

A total of 22 male college students participated in this study. The center of gravity (COG), the percentage of gait cycle (PGC) and the joint angle(JT) were collected as indications of postural control during walking. A quantitative analysis was conducted using a One-Way Repeated Measures ANOVA to examine the variations among the three groups.

Results

During myopic interventions, (1) the range of vertical COG changes is significant to be greater compared with normal vision (P < 0.05). (2) there was an significant increase in the PGC in single-legged support, accompanied by a decrease in the PGC in double-legged support, compared with normal vision (P < 0.05). (3) The myopic intervention leads to increased variability in JT of the hip and the knee during the single-leg support and swing, as compared to individuals with normal vision (P < 0.05). Severe myopic interventions result in more changes in JT of ankle.

Conclusion

Myopia has been found to have a negative impact on postural control during walking, leading to changes in balance, increased instability, and an elevated risk of injury.

The Sleep Quality- and Myopia-Linked PDE11A-Y727C Variant Impacts Neural Physiology by Reducing Catalytic Activity and Altering Subcellular Compartmentalization of the Enzyme

Recently, a Y727C variant in the dual-specific 3',5'-cyclic nucleotide phosphodiesterase 11A (PDE11A-Y727C) was linked to increased sleep quality and reduced myopia risk in humans. Given the well-established role that the PDE11 substrates cAMP and cGMP play in eye physiology and sleep, we determined if (1) PDE11A protein is expressed in the retina or other eye segments in mice, (2) PDE11A-Y7272C affects catalytic activity and/or subcellular compartmentalization more so than the nearby suicide-associated PDE11A-M878V variant, and (3) Pde11a deletion alters eye growth or sleep quality in male and female mice. Western blots show distinct protein expression of PDE11A4, but not PDE11A1-3, in eyes of Pde11a WT, but not KO mice, that vary by eye segment and age. In HT22 and COS-1 cells, PDE11A4-Y727C reduces PDE11A4 catalytic activity far more than PDE11A4-M878V, with both variants reducing PDE11A4-cAMP more so than PDE11A4-cGMP activity. Despite this, Pde11a deletion does not alter age-related changes in retinal or lens thickness or axial length, nor vitreous or anterior chamber depth. Further, Pde11a deletion only minimally changes refractive error and sleep quality. That said, both variants also dramatically alter the subcellular compartmentalization of human and mouse PDE11A4, an effect occurring independently of dephosphorylating PDE11A4-S117/S124 or phosphorylating PDE11A4-S162. Rather, re-compartmentalization of PDE11A4-Y727C is due to the loss of the tyrosine changing how PDE11A4 is packaged/repackaged via the trans-Golgi network. Therefore, the protective impact of the Y727C variant may reflect a gain-of-function (e.g., PDE11A4 displacing another PDE) that warrants further investigation in the context of reversing/preventing sleep disturbances or myopia.

The sleep quality- and myopia-linked PDE11A-Y727C variant impacts neural physiology by reducing catalytic activity and altering subcellular compartmentalization of the enzyme

Recently, a Y727C variant in the dual-specific 3',5'-cyclic nucleotide phosphodiesterase 11A (PDE11A-Y727C) was linked to increased sleep quality and reduced myopia risk in humans. Given the well-established role that the PDE11 substrates cAMP and cGMP play in eye physiology and sleep, we determined if 1) PDE11A protein is expressed in the retina or other eye segments in mouse, 2) PDE11A-Y7272C affects catalytic activity and/or subcellular compartmentalization more so than the nearby suicide-associated PDE11A-M878V variant, and 3) Pde11a deletion alters eye growth or sleep quality in male and female mice. Western blots show distinct protein expression of PDE11A4, but not PDE11A1-3, in eyes of Pde11a WT-but not KO mice-that vary by eye segment and age. In HT22 and COS-1 cells, PDE11A4-Y727C reduces PDE11A4 catalytic activity far more than PDE11A4-M878V, with both variants reducing PDE11A4-cAMP more so than PDE11A4-cGMP activity. Despite this, Pde11a deletion does not alter age-related changes in retinal or lens thickness, axial length, nor vitreous or anterior chamber depth. Further, Pde11a deletion only minimally changes refractive error and sleep quality. That said, both variants also dramatically alter the subcellular compartmentalization of human and mouse PDE11A4, an effect occurring independently of dephosphorylating PDE11A4-S117/S124 or phosphorylating PDE11A4-S162. Rather, re-compartmentalization of PDE11A4-Y727C is due to the loss of the tyrosine changing how PDE11A4 is packaged/repackaged via the trans-Golgi network. Therefore, the protective impact of the Y727C variant may reflect a gain-of-function (e.g., PDE11A4 displacing another PDE) that warrants further investigation in the context of reversing/preventing sleep disturbances or myopia.

LncRNA-XR_002792574.1-mediated ceRNA network reveals potential biomarkers in myopia-induced retinal ganglion cell damage

BACKGROUND

Long noncoding RNAs (lncRNAs) play a key role in the occurrence and progression of myopia. However, the function of lncRNAs in retinal ganglion cells (RGCs) in the pathogenesis of myopia is still unknown. The aim of our study was to explore the lncRNA-mediated competing endogenous RNA (ceRNA) network in RGCs during the development of myopia.

METHODS

RNA sequencing was performed to analyze lncRNA and mRNA expression profiles in RGCs between guinea pigs with form-deprived myopia (FDM) and normal control guinea pigs, and related ceRNA networks were constructed. Then, potentially important genes in ceRNA networks were verified by qRT‒PCR, and Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses were performed to explore biological functions in the RGCs of FDM guinea pigs. The important genes and related signaling pathways were further verified by qRT‒PCR, immunohistochemistry, immunofluorescence and Western blot in myopia in FDM guinea pigs, FDM mice, and highly myopic adults.

RESULTS

The distribution of RGCs was uneven, the number of RGCs was decreased, and RGC apoptosis was increased in FDM guinea pigs. In total, 873 lncRNAs and 2480 mRNAs were determined to be differentially expressed genes in RGCs from normal control and FDM guinea pigs. Via lncRNA-mediated ceRNA network construction and PCR verification, we found that lncRNA-XR_002792574.1 may be involved in the development of myopia through the miR-760-3p/Adcy1 pathway in RGCs. Further verification in FDM guinea pigs, FDM mice, and highly myopic adults demonstrated that the lncRNA-XR_002792574.1/miR-760-3p/Adcy1 axis in RGCs might be related to cGMP/PKG, the apelin signaling pathway and scleral remodeling.

CONCLUSION

We demonstrated that the lncRNA-XR_002792574.1/miR-760-3p/Adcy1 axis in RGCs might be related to myopia. On the one hand, the lncRNA-XR_002792574.1/miR-760-3p/Adcy1 axis might inhibit the cGMP/PKG and apelin signaling pathways in RGCs, thereby causing RGC damage in myopia. On the other hand, the lncRNA-XR_002792574.1/miR-760-3p/Adcy1 axis may cause myopic scleral remodeling through the ERK-MMP-2 pathway. These findings may reveal novel potential targets in myopia and provide reference value for exploration and development of gene editing therapeutics for hereditary myopia.

Association of mitochondrial DNA variation with high myopia in a Han Chinese population

High myopia (HM), which is characterized by oxidative stress, is one of the leading causes of visual impairment and blindness across the world. Family and population genetic studies have uncovered nuclear-genome variants in proteins functioned in the mitochondria. However, whether mitochondrial DNA mutations are involved in HM remains unexplored. Here, we performed the first large-scale whole-mitochondrial genome study in 9613 HM cases and 9606 control subjects of Han Chinese ancestry for identifying HM-associated mitochondrial variants. The single-variant association analysis identified nine novel genetic variants associated with HM reaching the entire mitochondrial wide significance level, including rs370378529 in ND2 with an odds ratio (OR) of 5.25. Interestingly, eight out of nine variants were predominantly located in related sub-haplogroups, i.e. m.5261G > A in B4b1c, m.12280A > G in G2a4, m.7912G > A in D4a3b, m.94G > A in D4e1, m.14857 T > C in D4e3, m.14280A > G in D5a2, m.16272A > G in G2a4, m.8718A > G in M71 and F1a3, indicating that the sub-haplogroup background can increase the susceptible risk for high myopia. The polygenic risk score analysis of the target and validation cohorts indicated a high accuracy for predicting HM with mtDNA variants (AUC = 0.641). Cumulatively, our findings highlight the critical roles of mitochondrial variants in untangling the genetic etiology of HM.