Inhibitory effect of miR-138-5p on choroidal fibrosis in lens-induced myopia guinea pigs via suppressing the HIF-1α signaling pathway

Selenide-modified hyaluronic acid hydrogel promotes scleral remodeling during the recovery phase of form-deprivation myopia by inhibiting HIF-1α-mediated inflammation

This study investigates the molecular mechanisms by which selenide-modified hyaluronic acid hydrogel (Se-HA gel) promotes scleral remodeling during the recovery phase of form-deprivation myopia (FDM). The Se-HA gel was synthesized and characterized, exhibiting an average hydrodynamic diameter of 191.72 nm, a polydispersity index (PDI) of 0.19, and a zeta potential of -7.96 mV, indicating a monodisperse state in PBS. Both in vitro experiments and the FDM mouse model confirmed its therapeutic efficacy. At a concentration of 250 μg/mL, Se-HA gel significantly promoted fibroblast proliferation, inhibited apoptosis, and prevented transdifferentiation. A 200 mg/kg subtenon injection improved key ocular biometric parameters in FDM mice. Single-cell and transcriptomic sequencing analyses revealed that Se-HA gel facilitated scleral remodeling by downregulating Hypoxia-Inducible Factor 1 Alpha (HIF-1α) expression and regulating inflammation-related gene expression. Notably, HIF-1α overexpression reversed the beneficial effects of Se-HA gel, reinforcing its pivotal role in mediating these therapeutic outcomes. This study introduces a novel biomaterial-based strategy and identifies new molecular targets for myopia treatment. Furthermore, it addresses a critical gap in understanding how Se-HA gel promotes scleral remodeling through HIF-1α-mediated signaling pathways, with important scientific and translational potential in the field of myopia management.

Elevated thiamine level is associated with activating interaction between HIF-1α and SLC19A3 in experimental myopic guinea pigs

Background

The SLC19 gene family of solute carriers is a family of three transporter proteins with similar structures, of which SLC19A2 and SLC19A3 mediate thiamin transport; HIF is a transcriptionally active nuclear protein that is a key factor activated in hypoxic environments. Myopia is the most common eye disease that damages the visual health of adolescents, and currently, choroidal hypoxia is one of the prevailing doctrines of myopia, as well as the choroid as an ocular nutrient-supporting tissue, in which thiamine may play a role. This study aimed to investigate the process of thiamine changes in choroidal tissue of guinea pigs with negative lens-induced myopia (LIM).

Methods

The right eyes of guinea pigs in the LIM group wore -6.0D lenses to model experimental myopia. Biological measurements of ocular parameters and choroidal thickness (ChT) were measured after 2, 4, and 6 weeks of modeling. Real-time fluorescence quantitative PCR and Western blot were used to detect the expression of SLC19A2, SLC19A3, and HIF-1α in the choroidal tissues of each guinea pig, ELISA was used to detect the changes of thiamine content in the choroidal tissues, and HE staining was used to observe the morphological changes of the choroidal tissues. Immunofluorescence and immunohistochemistry detected the expression of SLC19A3 and SLC19A3 in choroidal tissues at different modeling times, and protein immunoprecipitation and molecular docking verified the interactions between HIF-1α and SLC19A3.

Results

Compared with the normal control (NC) group, the LIM group guinea pigs showed a significant increase in axial length and decrease in refractive error, as well as a thinning of choroidal thickness and loosening of tissue structure. In addition, the expression of SLC19A3 was higher than that of the NC group at 2 and 4 weeks, SLC19A2 was higher than that of the NC group at 4 weeks, and HIF-1α was higher than that of the NC group at 2, 4, and 6 weeks. Moreover, protein immunoprecipitation revealed a reciprocal relationship between HIF-1α and SLC19A3, and molecular docking showed their sites of action.

Conclusion

The current study suggests that the choroidal tissue in myopic eyes is hypoxic and has metabolic abnormalities. Thiamine, a critical molecule for metabolism, may play a significant role in the process. Our findings indicate that changes in thiamine levels within the choroidal tissue are associated with elevated choroidal HIF-1α and activation of SLC19A3, which enhances thiamine transport. This suggests an adaptive regulatory mechanism for thiamine in myopia. Our research highlights thiamine as a potential target for pharmacological inhibitors and could lead to new insights into the study of the molecular mechanisms of myopia, as well as novel strategies for treating the disease.

Inhibitory effect of Zhujing Pill on myopia progression: Mechanistic insights based on metabonomics and network pharmacology

OBJECTIVES

This study endeavored to uncover the mechanisms by which Zhujing pill (ZJP) slows myopia progression.

METHODS

We employed biometric analyses to track diopter and axial length changes in guinea pigs with negative lens-induced myopia (LIM). Through integrating metabonomics and network pharmacology, we aimed to predict the anti-myopic targets and active ingredients of ZJP. Subsequent analysis, including real-time fluorescent quantitative PCR (qPCR) and Western blotting (WB), assessed the expression levels of CHRNA7, LPCAT1, and NOS2 in retinal tissues.

KEY FINDINGS

Our findings demonstrate that ZJP significantly mitigates diopter increase and axial elongation in LIM guinea pigs. Metabonomic analysis revealed significant changes in 13 serum metabolites, with ZJP reversing the expression of 5 key metabolites. By integrating metabonomics with network pharmacology, we identified core targets of ZJP against myopia and constructed a compound-gene-disease-metabolite network. The expressions of LPCAT1 and CHRNA7 were found to decrease in the LIM group but increase with ZJP treatment, whereas NOS2 expression showed the opposite pattern.

CONCLUSIONS

This investigation provides the first evidence of ZJP's multifaceted effectiveness in managing myopia, highlighting its impact on multiple components, targets, and pathways, including the novel involvement of LPCAT1 and CHRNA7 in myopia pathogenesis.

Animal modeling for myopia

Background

Myopia is one of the most common eye diseases globally, and has become an increasingly serious health concern among adolescents. Understanding the factors contributing to the onset of myopia and the strategies to slow its progression is critical to reducing its prevalence.

Main text

Animal models are key to understanding of the etiology of human diseases. Various experimental animal models have been developed to mimic human myopia, including chickens, rhesus monkeys, marmosets, mice, tree shrews, guinea pigs and zebrafish. Studies using these animal models have provided evidences and perspectives on the regulation of eye growth and refractive development. This review summarizes the characteristics of these models, the induction methods, common indicators of myopia in animal models, and recent findings on the pathogenic mechanism of myopia.

Conclusions

Investigations using experimental animal models have provided valuable information and insights into the pathogenic mechanisms of human myopia and its treatment strategies.

Electroacupuncture improves retinal function in myopia Guinea pigs probably via inhibition of the RhoA/ROCK2 signaling pathway

Objective

To investigate the effect of electroacupuncture (EA) on retinal function in guinea pigs with negative lens-induced myopia (LIM) by inhibiting the RhoA/ROCK2 signaling pathway.

Methods

Guinea pigs were randomly divided into normal control (NC) group, LIM group, EA group, SHAM acupoint (SHAM) group, and electro-acupuncture + ROCK pathway inhibitor Y27632 (EA + Y27632) group. The refraction, axial length, retinal blood flow density, choroidal vascular index, retinal physiological function, the contents of total antioxidant capacity (T-AOC), catalase (CAT), glutathione (GSH), superoxide dismutase (SOD) and malondialdehyde (MDA) of each group were determined. The changes in retinal tissue structure were observed by hematoxylin and eosin (H&E) staining, and the expression of the RhoA/ROCK2 signaling pathway-related molecules in the retina was measured by real-time quantitative polymerase chain reaction (qPCR) and Western blot.

Results

Myopic refraction, AL, and MDA content in the LIM and SHAM groups were significantly increased, retinal blood flow density and CVI, SOD, GSH, CAT, T-AOC content were decreased. After EA intervention, myopic refraction, AL, and MDA content decreased, retinal blood flow density and CVI, SOD, GSH, CAT, T-AOC content were increased. H&E staining showed that the thickness of the guinea pig retina, the thickness of the inner and outer layers of the nucleus, and the number of cells were significantly increased after EA intervention. qPCR and western blot analyses showed that the expression of RhoA、ROCK2、MLC、CollagenⅠ、MMP-2、TIMP-2 and α-SMA were elevated in the LIM and SHAM group than those in the NC group. Compared with the LIM group, the expression of EA group was significantly decreased.

Conclusions

Electroacupuncture can improve retinal function by improving retinal blood flow, reducing retinal oxidative damage, inhibiting RhoA/ROCK2 signaling pathway and controlling extracellular matrix remodeling, thus delaying the occurrence and development of myopia.

Targeting MicroRNA in myopia: Current insights

Myopia, the most prevalent eye condition, has sparked notable interest regarding its origin and prevention. MicroRNAs (miRNAs) are short, non-coding RNA strands typically consisting of 18-24 nucleotides. They play a central role in post-transcriptional gene regulation and are closely associated with both normal and pathological processes in organisms. Recent advances in next-generation sequencing and bioinformatics have provided novel insights into miRNA expression and its regulatory role in myopia. This review discusses the distinct expression patterns, regulatory functions, and potential pathways of miRNAs involved in the onset and progression of myopia. The primary objective of this review was to provide valuable insights into molecular mechanisms underlying myopia and the contribution of miRNAs. These insights are expected to pave the way for further exploration of the molecular mechanisms, diagnosis, treatment, and clinical applications of myopia.

miR-92b-3p protects retinal tissues against DNA damage and apoptosis by targeting BTG2 in experimental myopia

BACKGROUND

Myopia is one of the eye diseases that can damage the vision of young people. This study aimed to explore the protective role of miR-92b-3p against DNA damage and apoptosis in retinal tissues of negative lens-induced myopic (LIM) guinea pigs by targeting BTG2.

METHODS

Biometric measurements of ocular parameters, flash electroretinogram (FERG), and retinal thickness (RT) were performed after miR-92b-3p intravitreal injection in LIM guinea pigs. The apoptotic rate was detected by Annexin V-FITC/PI double staining, and the change in mitochondrial membrane potential was measured by JC-1 staining. Retinal apoptosis and expression of p53, BTG2, and CDK2 were explored by TdT-mediated dUTP-biotin nick labeling (TUNEL) and immunofluorescence staining assays, respectively. BTG2 and its upstream and downstream molecules at gene and protein levels in retinal tissues were measured by real-time quantitative PCR (qPCR) and Western blotting.

RESULTS

Compared with normal controls (NC), the ocular axial length of LIM guinea pig significantly increased, whereas refraction decreased. Meanwhile, dMax-a and -b wave amplitudes of ERG declined, retinal thickness was decreased, the number of apoptotic cells and apoptotic rate in LIM eyes was exaggerated, and the mitochondrial membrane potential significantly decreased. In addition, results of qPCR and Western blot assays showed that the expression levels of p53, BTG2, CDK2, and BAX in LIM guinea pigs were higher than the levels of the NC group, whereas the BCL-2 expression level was decreased. By contrast, the miR-92b-3p intravitreal injection in LIM guinea pigs could significantly inhibit axial elongation, alleviate DNA damage and apoptosis, and thus protect guinea pigs against myopia.

CONCLUSION

In conclusion, p53 and BTG2 were activated in the retinal tissue of myopic guinea pigs, and the activated BTG2 could elevate the expression of CDK2 and BAX, and attenuate the expression of BCL-2, which in turn promote apoptosis and eventually lead to retinal thinning and impaired visual function in myopic guinea pigs. The miR-92b-3p intravitreal injection can attenuate the elongation of ocular length and retinal thickness, and inhibit the CDK2, BAX, and p53 expression by targeting BTG2, thereby ameliorating DNA damage and apoptosis in LIM guinea pigs and protecting ocular tissues.

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.

MiR-181a-5p may regulate cell proliferation and autophagy in myopia and the associated retinopathy

The mechanism of myopia and the associated retinopathy remains unclear, and dysregulated microRNAs (miRNAs) are implicated in this disease. In this research, we purposed to find out the regulatory function that miRNAs play in myopia and the associated retinopathy. We first performed miRNA microarray analysis in a lens-induced myopia mouse model and found that miR-9-5p, miR-96-5p, miR-182-5p, miR-183-5p, and miR-181a-5p were elevated in the myopic retina. Then, we examined the functions and regulatory mechanisms of miR-181a-5p utilizing the human retinal pigment epithelium (RPE) cell line ARPE-19 by overexpressing miR-181a-5p. RNA sequencing (RNA-Seq) and qRT-PCR analysis were employed to identify differentially expressed genes after transfection. The qRT‒PCR outcomes, immunoblotting, and immunofluorescence indicated that the SGSH expression was significantly hindered through miR-181a-5p overexpression. MiR-181a-5p overexpression has the ability to elevate RPE cell proliferation and induce autophagy by targeting SGSH. We validated the negative influence of miR-181a-5p on the SGSH expression through luciferase reporter assays, which demonstrated its ability to target the 3' untranslated region of SGSH. The reversal of implications of miR-181a-5p overexpression was achieved through SGSH upregulation. We provided novel perspectives into the miR-181a-5p function in regulating myopia development and may serve as a target for therapy and molecular biomarker for myopia.

Suppressive effect of nitric oxide synthase (NOS) inhibitor L-NMMA acetate on choroidal fibrosis in experimental myopic guinea pigs through the nitric oxide signaling pathway

Myopia is one of the most prevalent eye diseases that seriously threaten the eyesight of children and adolescents worldwide. However, the pathogenesis is still unclear, and effective drugs are still scarce. In the present study, the guinea pigs were randomly divided into a normal control (NC) group, a lens-induced myopia (LIM) group, a NOS inhibitor (L-NMMA) injection group, and a NOS inhibitor solvent phosphate-buffered saline (PBS) group and the animals received relevant treatments. After 2- and 4-week different treatments, we noted that the refraction and choroidal thickness in the LIM group decreased compared with the NC group, whereas the ocular axial length increased significantly, and the choroid showed a fibrotic trend. The expression of NOS1, NOS3, TGF-β1, COLI, and α-SMA at gene and protein levels was increased significantly in the choroid (all P < 0.05). After intravitreal injection of NOS inhibitor L-NMMA, we found that compared with the LIM group, the refraction and the choroidal thickness significantly increased, whereas the axial length reduced significantly, accompanied by an increase of choroidal thickness and an improvement of choroidal fibrosis. The expression levels of choroidal NOS1, NOS3, TGF-β, COLI, and α-SMA were significantly reduced (all P < 0.05). In conclusion, the trend of choroidal fibrosis in LIM guinea pigs is positively correlated with the increase in axial length. The NOS inhibitor L-NMMA can alleviate the process of choroidal fibrosis in myopic guinea pigs by inhibiting NO signaling pathway.