Scleral PERK and ATF6 as targets of myopic axial elongation of mouse eyes

Nrf3-Mediated Mitochondrial Superoxide Promotes Cardiomyocyte Apoptosis and Impairs Cardiac Functions by Suppressing Pitx2

BACKGROUND

Myocardial infarction (MI) elicits mitochondria reactive oxygen species (ROS) production and cardiomyocyte (CM) apoptosis. Nrf3 (nuclear factor erythroid 2-related factor 3) has an established role in regulating redox signaling and tissue homeostasis. Here, we aimed to evaluate the role and mechanism of Nrf3 in injury-induced pathological cardiac remodeling.

METHODS

Global (Nrf3-KO) and CM-specific (Nrf3△CM) Nrf3 knockout mice were subjected to MI or ischemia/reperfusion injury, followed by functional and histopathological analysis. Primary neonatal mouse and rat ventricular myocytes and CMs derived from human induced pluripotent stem cells were used to evaluate the impact of Nrf3 on CM apoptosis and mitochondrial ROS production. Chromatin immunoprecipitation sequencing and immunoprecipitation-mass spectrometry analysis were used to uncover potential targets of Nrf3. MitoParaquat administration and CM-specific adeno-associated virus vectors were used to further confirm the in vivo relevance of the identified signal pathways.

RESULTS

Nrf3 was expressed mainly in CMs in healthy human hearts, and an increased level of Nrf3 was observed in CMs within the border zone of infarcted human hearts and murine cardiac tissues after MI. Both global and CM-specific Nrf3 knockout significantly decreased injury-induced mitochondrial ROS production, CM apoptosis, and pathological cardiac remodeling, consequently improving cardiac functions. In addition, cardiac-specific Nrf3 overexpression reversed the ameliorative cardiac phenotypes observed in Nrf3-KO mice. Functional studies showed that Nrf3 promoted neonatal mouse ventricular myocyte, neonatal rat ventricular myocyte, and CMs derived from human induced pluripotent stem cell apoptosis by increasing mitochondrial ROS production. Critically, augmenting mitochondrial ROS with MitoParaquat blunted the beneficial effects of Nrf3 deletion on cardiac function and remodeling. Mechanistically, a redox regulator Pitx2 (paired-like homeodomain transcription factor 2) was identified as one of the main target genes of Nrf3. Specifically, Nrf3 binds to Pitx2 promoter, where it increases DNA methylation through recruiting heterogeneous nuclear ribonucleoprotein K and DNA-methyltransferase 1 complex, thereby inhibiting Pitx2 expression. CM-specific knockdown of Pitx2 blunted the beneficial effects of Nrf3 deletion on cardiac function and remodeling, and cardiac-specific Pitx2 overexpression attenuated MI-induced mitochondrial ROS production and CM apoptosis, as well as preserved cardiac functions after MI.

CONCLUSIONS

Nrf3 promotes injury-induced CM apoptosis and deteriorates cardiac functions by increasing mitochondrial ROS production through suppressing Pitx2 expression. Targeting the Nrf3-Pitx2-mitochondrial ROS signal axis may therefore represent a novel therapeutic approach for MI treatment.

New insights on mesenchymal stem cells therapy from the perspective of the pathogenesis of nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) manifests as chronic hepatic steatosis, occurring variably across people due to racial and genetic diversity. It represents a stage in the development of chronic liver disease, marked by fat accumulation, inflammatory responses, oxidative stress in the endoplasmic reticulum, and fibrosis as primary concerns. Understanding its underlying mechanisms remains a challenging and pivotal area of study. In the past, acute liver injury-related diseases were commonly treated with methods such as liver transplantation. However, the emergence of artificial liver has shifted focus to stem cell therapies. Unlike conventional drugs, stem cell therapies are continuously evolving. Despite being classified as drugs, stem cells demonstrated significant efficacy after multiple injections. Mesenchymal stem cells, unlike other types of stem cells, do not have the risk of tumor formation and low immunogenicity, reducing the hypersensitivity reactions associated with liver transplantation. Increasingly, studies suggest that mesenchymal stem cells hold promise in the treatment of chronic liver injury diseases. This review focuses on investigating the role of mesenchymal stem cells in chronic metabolic liver diseases, such as non-alcoholic fatty liver disease, and delves into their specific functions.

Endoplasmic reticulum stress contributes to the development of ocular graft-vs-host disease in the eyelids and the ocular surface

BACKGROUND

While endoplasmic reticulum (ER) stress has been implicated in various aspects of graft-versus-host disease (GVHD), its effects on the eyelids and ocular surface in patients with chronic GVHD (cGVHD) remains poorly understood. We aimed to investigate the relationship between ER stress and ocular GVHD using the ER stress suppressor, 4-phenylbutyric acid (PBA).

METHODS

The study used allogeneic bone marrow transplantation (BMT) and syngeneic BMT to establish a cGVHD mouse model. cGVHD mice were treated with either intraperitoneal administration of PBA or 2 % PBA eye drops following BMT.

RESULTS

The Intraperitoneal PBA-treated (PBAip) group retained a larger meibomian gland (MG) area and corneal epithelial damage and inflammatory and fibrotic cell infiltration in the ocular surface was attenuated compared to vehicle-treated cGVHD mice. The expression of unfolded protein response markers was significantly elevated in the vehicle group compared to the syngeneic control and the PBAip group. Electron microscopy and immunohistochemistry revealed that fibroblasts and macrophages infiltrated the eyelids and ocular surface of cGVHD mice under ER stress. The corneal fluorescein staining score was significantly lower in the PBA eye drop-treated group than in the vehicle-treated group. The numbers of leukocyte marker CD45-, T cell marker CD4-, and macrophage marker F4/80-positive cells were significantly reduced in the PBA eye drop-treated group compared to the vehicle group.

CONCLUSIONS

The study suggests that the ER stress response, which is triggered by cGVHD in ocular surface tissues, can be suppressed by PBA, an ER stress suppressor, potentially offering therapeutic benefits in ocular GVHD.

Transcriptomic and proteomic analyses of sclera in lens-induced myopic guinea pigs

BACKGROUND

Myopia development is commonly assessed by an increase in axial length, which may lead to high myopia and visual impairment. This study aims to identify potential biomarkers and signaling pathways in the sclera during experimental axial elongation.

METHODS

A myopia guinea pig model was established using male guinea pigs aged 2-3 weeks, which underwent bilateral lens-induced myopization (LIM) (study group) or were left untreated (control group). An integrated analysis of transcriptomic and proteomic was performed to identify differentially expressed genes (DEGs) in the sclera. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses were conducted to explore the DEGs related signaling pathways. Promising candidate markers were further tested by Western blot analysis. Transmission electron microscopy was used to assess scleral fiber changes in myopic guinea pigs.

RESULTS

During the study period, axial elongation was significantly greater in the study group (0.59 ± 0.05 mm vs. 0.47 ± 0.02 mm; P < 0.001), accompanied by a reduction in the thickness of the retina (121.9 ± 2.50 μm vs. 134.6 ± 0.48 μm; P < 0.001), choroid (38 ± 1.0 μm vs. 50 ± 0.8 μm; P < 0.001), and sclera (100.8 ± 2.78 μm vs. 155.6 ± 4.78 μm; P < 0.001). Integrated transcriptomic and proteomic analyses identified 34 upregulated genes, with significant activation and enrichment of the circadian rhythm pathway. Among the top enriched pathways, key differentially expressed genes included retinoid-related orphan receptors RORα and RORβ, which are recognized as critical signals modulating the scleral hypoxia response. Western blot analysis confirmed upregulation of RORα, RORβ, melatonin receptor type 1 (MT1), and HIF-1α in the sclera, while melatonin receptor type 2 (MT2) expression remained unchanged between the groups. Transmission electron microscopy revealed a significantly higher proportion of thin collagen fibers compared to thick fibers in the LIM group (P < 0.05).

CONCLUSIONS

Axial elongation-related remodeling of scleral collagen is closely linked to circadian rhythm and hypoxia pathways, with RORα, RORβ, melatonin receptors, and HIF-1α identified as potential key regulators. Additionally, scleral fiber size decreases progressively with scleral remodeling in myopia development.

Comprehensive bioinformatics analysis of metabolism‑related microRNAs in high myopia in young and old adults with age‑related cataracts

High myopia and age‑related cataracts are prevalent ocular disorders that compromise visual acuity. The molecular mechanisms underlying these conditions remain largely unclear. Here, microRNA (miRNA or miR) sequencing was performed on aqueous humor samples obtained from individuals with age‑related cataracts and high myopia (AH, n=9), young patients with high myopia (YH, n=9) and a control group of elderly patients with age‑related cataracts, matched in terms of sex and age (AN, n=9). miRNA sequencing and differential expression were performed. Intersecting miRNAs were identified, as well as metabolism‑related genes from MsigDB were intersected with miRNA target genes. Functional enrichment was performed and disease targets predicted using DisGeNET. A protein‑protein interaction network was built with STRING, and hub genes were identified via Cytoscape. GeneMANIA analyzed hub genes, while drug predictions were made using Comparative Toxicogenomics Database. Long non‑coding RNAs and transcription factors were predicted via mirNet and ChEA3. Results were validated by RT‑qPCR. A total of 18 miRNAs were significantly differential expressed between AH and AN group, of which eight were up‑ and 10 were downregulated. A total of 23 miRNAs were significantly differential expressed between the YH and AN group, of which six were up‑ and 17 were downregulated. hsa‑miR‑490‑3p, hsa‑miR‑4423‑3p and hsa‑miR‑4485‑3p may serve as characteristic miRNAs. A total of 289 target genes were predicted. Functional enrichment analysis yielded 169 terms, with 'herpes simplex virus 1 infection' the most significantly enriched. There were 19 metabolism‑associated target genes linked with these miRNAs, suggesting a potential role of metabolic processes in pathogenesis of these conditions. The biosynthetic process of carbohydrate derivatives may serve a key role during the development of high myopia. There were 10 hub genes and Propionyl‑CoA Carboxylase Subunit β could potentially serve as a biomarker. Drugs that could modulate their function were predicted; cyclosporine, tretinoin and acetaminophen may exert a broad influence on these hub genes. Hub gene networks based on the miRNAs were constructed to predict 44 associated long non‑coding RNAs and 98 transcription factors. The present findings offer novel insights into the molecular mechanisms of age‑related cataracts and high myopia and propose potential therapeutic targets.

Distribution and associated factors of choroidal thickness in highly myopic eyes-a real-world study based on a Chinese population

PURPOSE

To measure the subfoveal choroidal thickness (SFCT) in highly myopic eyes at different locations using enhanced depth imaging spectral-domain optical coherence tomography (EDI SD-OCT). To identify the ocular and systemic risk factors associated with choroidal thinning in high myopia.

METHODS

Based on the Beijing Eye Study, a detailed ophthalmic examination was performed including EDI SD-OCT for the measurement of SFCT. OCT images were obtained from 103 highly myopic eyes (≥ -6.00 dioptres) and 227 normal eyes randomly selected from the baseline population, matched for age and sex.

RESULTS

The mean SFCT was 110.6 ± 85.2 μm in highly myopic eyes (range, 3-395 μm). Mean regional choroidal thickness was lowest on the nasal and inferior sides of the macula, and slightly higher on the temporal and superior sides than at the fovea. On multivariate analysis, SFCT was associated with age (b = -0.48; P < 0.001), axial length (b = -0.44; P < 0.001), gender (b = -0.31; P < 0.05) and staphyloma (b = -0.26; P = 0.05). In highly myopic eyes, SFCT decreased by 5.1 μm/year of age, by 9.2 µm/D of myopia, and by 22.6 µm/mm of axial length.

CONCLUSIONS

The SFCT decreases with age and increased axial length in highly myopic eyes. The formation of a posterior staphyloma has been identified as a major contributor to choroidal thinning and is therefore a reliable indicator for risk management. The involvement of choroidal abnormalities may be a significant factor in the development of myopic degeneration.

The potential role of amino acids in myopia: inspiration from metabolomics

BACKGROUND

Due to the high prevalence of myopia, there is a growing need for the identification of myopia intervention mechanisms and targets. Metabolomics has been gradually used to investigate changes in myopia tissue metabolites over the last few years, but the potential physiological and pathological roles of amino acids and their downstream metabolites discovered by metabolomics in myopia are not fully understood.

AIM OF REVIEW

Aim to explore the possible relationship between amino acid metabolism and the occurrence and development of myopia, we collected a total of 21 experimental studies related to myopia metabolomics. Perform pathway analysis using MetaboAnalyst online software. We have identified over 20 amino acids that may be associated with the development of myopia. Among them, 19 types of amino acids are common amino acids. We discussed their possible mechanisms affecting myopia and proposed future prospects for treating myopia.

KEY SCIENTIFIC CONCEPTS OF REVIEW

Our analysis results show that metabolomics research on myopia involves many important amino acids. We have collected literature and found that research on amino acid metabolism in myopia mainly focuses on downstream small molecule substances. Amino acids and their downstream metabolites affect the development of myopia by participating in important biochemical processes such as oxidative stress, glucose metabolism, and lipid metabolism. Enzymes, receptors, and cytokines that regulate amino acid metabolism may become potential targets for myopia treatment.

Quercetin Alleviates Scleral Remodeling Through Inhibiting the PERK-EIF2α Axis in Experiment Myopia

Purpose

This study aims to investigate the effect of quercetin (QUE) on scleral remodeling by inhibiting the PERK-EIF2α signaling pathway and to evaluate its potential role in slowing myopia.

Methods

Lens-induced myopia (LIM) guinea pigs were obtained and treated with QUE. After 4 and 6 weeks of treatments, ocular biological measurements were conducted. Hematoxylin and eosin (H&E) staining was used to observe the changes in scleral morphology and thickness, and Masson staining was used to examine scleral collagen fiber arrangement. Quantitative PCR (qPCR) and Western bolt were utilized to detect the mRNA and protein expression of PERK, EIF2α, MMP-2, TIMP-2, and collagen I in the scleral tissues. Calcium ion flow in each group was measured using noninvasive micro-test technology, and reactive oxygen species levels were detected by flow cytometry.

Results

Compared with the LIM group, the ocular measurements showed that the refractive errors and axial length of the eyes were significantly reduced in the LIM + QUE group (P < 0.01). H&E and Masson staining showed that sclera in the LIM + QUE group was thickened, collagen was dense, and the fiber gap was reduced. In the LIM + QUE group, the expression levels of PERK, EIF2α, and MMP-2 were decreased, whereas the expression levels of TIMP-2 and collagen I were increased. Calcium release and reactive oxygen species (ROS) in the LIM + QUE group were decreased.

Conclusions

Quercetin ameliorates scleral remodeling in myopic guinea pigs by inhibiting the PERK-EIF2α signaling pathway, thereby alleviating the progression of myopia. These findings provide new experimental evidence for the potential application of quercetin in myopia prevention and treatment.

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.

Myopic shift in female mice after ovariectomy

Myopia is a global public health concern, with a higher prevalence in women than that in male. As the relationship between sex hormone and myopia remains unclear, we aimed to reveal the relationship between sex hormone and myopia by removing the ovaries of mice and measuring changes in ocular parameters related to myopia. Lens-induced myopia (LIM) surgeries were performed on 3-week-old male mice and age-matched female mice to evaluate the effects of sex on myopia development, which indicated a high degree of myopia and rapid progression of axial elongation in male mice. Bilateral ovariectomy (OVX) performed on 4-week-old female mice induced myopic refraction status in ovariectomized mice. Although axial length elongation was larger in ovariectomized mice than that in sham control mice, the result was insignificant. To further reveal the relationship between female sex hormones and myopia, LIM combined with OVX was performed, which revealed a magnified myopic refraction status in ovariectomized mice. Nevertheless, elongation of the anterior chamber depth in the - 30 D lens-treated eyes significantly increased in LIM + OVX mice compared with the frame-treated eyes in LIM + OVX mice and - 30 D lens-treated eyes in LIM + Sham surgery mice. Sex hormones play a role in regulating myopia development in female mice.

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.

Investigation roles of Adamts1 and Adamts5 in scleral fibroblasts under hypoxia and mice with form-deprived myopia

Scleral hypoxia is considered a trigger in scleral remodeling-induced myopia. Identifying differentially expressed molecules within the sclera is essential for understanding the mechanism of myopia. We developed a scleral fibroblast hypoxia model and conducted RNA sequencing and bioinformatic analysis. RNA interference technology was then applied to knock down targeted genes with upregulated expression, followed by an analysis of COLLAGEN I protein level. Microarray data analysis showed that the expression of Adamts1 and Adamts5 were upregulated in fibroblasts under hypoxia (t-test, p < 0.05). Western blot analysis confirmed increased protein levels of ADAMTS1 and ADAMTS5, and a concurrent decrease in COLLAGEN I in hypoxic fibroblasts. The knockdown of either Adamts1 or Adamts5 in scleral fibroblasts under hypoxia resulted in an upregulation of COLLAGEN I. Moreover, a form-deprivation myopia (FDM) mouse model was established for validation. The sclera tissue from FDM mice exhibited increased levels of ADAMTS1 and ADAMTS5 protein and a decrease in COLLAGEN I, compared to controls. The study suggests that Adamts1 and Adamts5 may be involved in scleral remodeling induced by hypoxia and the development of myopia.

Insights into Myopia from Mouse Models

Animal models are critical for understanding the initiation and progression of myopia, a refractive condition that causes blurred distance vision. The prevalence of myopia is rapidly increasing worldwide, and myopia increases the risk of developing potentially blinding diseases. Current pharmacological, optical, and environmental interventions attenuate myopia progression in children, but it is still unclear how this occurs or how these interventions can be improved to increase their protective effects. To optimize myopia interventions, directed mechanistic studies are needed. The mouse model is well-suited to these studies because of its well-characterized visual system and the genetic experimental tools available, which can be combined with pharmacological and environmental manipulations for powerful investigations of causation. This review describes aspects of the mouse visual system that support its use as a myopia model and presents genetic, pharmacological, and environmental studies that significantly contribute to our understanding of the mechanisms that underlie myopigenesis.

Gut microbiota-derived indole-3-acetic acid suppresses high myopia progression by promoting type I collagen synthesis

High myopia (HM) is a leading cause of blindness worldwide with currently no effective interventions available. A major hurdle lies in its often isolated perception as a purely ocular morbidity, disregarding potential systemic implications. Recent evidence suggests the existence of a gut-eye axis; however, the role of gut microbiota in the pathogenesis of HM remains largely unexplored. Herein, we provide a potential crosstalk among HM's gut dysbiosis, microbial metabolites, and scleral remodeling. Utilizing 16S rRNA gene sequencing, we observed an altered gut microbiota profile in HM patients with a significant reduction in probiotic abundance compared with healthy controls. Subsequent targeted metabolic profiling revealed a notable decrease in plasma levels of the gut microbiota-derived metabolite indole-3-acetic acid (3-IAA) among HM patients, which is closely associated with the reduced probiotics, both negatively correlated with HM severity. Genetic analyses determined that gut microbiota are causally associated with myopia risk. Importantly, when mice subjected to HM modeling receive fecal microbiota transplantation from healthy donors, there is an increase in 3-IAA plasma levels and simultaneous retardation of HM progression along with better maintenance of collagen type I alpha 1 (COL1A1) expression in the sclera. Furthermore, 3-IAA gavage achieves similar effects. Mechanistic investigations confirm the transcriptional activation of COL1A1 by 3-IAA via promoting the enrichment of SP1 to its promoter. Together, our findings provide novel insights into the gut microbiota-eye axis in the pathogenesis of HM and propose new strategies for HM intervention by remodeling the gut microbiota and indole supplementation.

Exome-wide association study identifies KDELR3 mutations in extreme myopia

Extreme myopia (EM), defined as a spherical equivalent (SE) ≤ -10.00 diopters (D), is one of the leading causes of sight impairment. Known EM-associated variants only explain limited risk and are inadequate for clinical decision-making. To discover risk genes, we performed a whole-exome sequencing (WES) on 449 EM individuals and 9606 controls. We find a significant excess of rare protein-truncating variants (PTVs) in EM cases, enriched in the retrograde vesicle-mediated transport pathway. Employing single-cell RNA-sequencing (scRNA-seq) and a single-cell polygenic burden score (scPBS), we pinpointed PI16 + /SFRP4+ fibroblasts as the most relevant cell type. We observed that KDELR3 is highly expressed in scleral fibroblast and involved in scleral extracellular matrix (ECM) organization. The zebrafish model revealed that kdelr3 downregulation leads to elongated ocular axial length and increased lens diameter. Together, our study provides insight into the genetics of EM in humans and highlights KDELR3's role in EM pathogenesis.

Identification of activating transcription factor 6 (ATF6) as a novel prognostic biomarker and potential target in oral squamous cell carcinoma

BACKGROUND

Oral squamous cell carcinoma (OSCC) is originating from oral mucosal epithelial cells. Autophagy plays a crucial role in cancer treatment by promoting cellular self-degradation and eliminating damaged components, thereby enhancing therapeutic efficacy. In this study, we aim to identify a novel autophagy-related biomarker to improve OSCC therapy.

METHODS

We firstly utilized Cox and Lasso analyses to identify that ATF6 is associated with OSCC prognosis, and validated the results by Kaplan-Meier survival analysis. We further identified the downstream pathways and related genes by enrichment analysis and WGCNA analysis. Subsequently, we used short interfering RNA to investigate the effects of ATF6 knockdown on proliferation, migration, apoptosis, and autophagy in SCC-9 and SCC-15 cells through cell viability assay, transwell assay, EdU incorporation assay, flow cytometry analysis, western blot analysis and immunofluorescence analysis, etc. RESULTS: Bioinformatics analyses showed that ATF6 overexpression was associated with prognosis and detrimental to survival. In vitro studies verified that ATF6 knockdown reduced OSCC cell proliferation and migration. Mechanistically, ATF6 knockdown could promote cellular autophagy and apoptosis.

CONCLUSION

We propose that ATF6 holds potential as a prognostic biomarker linked to autophagy in OSCC. This study provides valuable clues for further exploration of targeted therapy against OSCC.

Scleral remodeling during myopia development in mice eyes: a potential role of thrombospondin-1

BACKGROUND

Scleral extracellular matrix (ECM) remodeling plays a crucial role in the development of myopia, particularly in ocular axial elongation. Thrombospondin-1 (THBS1), also known as TSP-1, is a significant cellular protein involved in matrix remodeling in various tissues. However, the specific role of THBS1 in myopia development remains unclear.

METHOD

We employed the HumanNet database to predict genes related to myopic sclera remodeling, followed by screening and visualization of the predicted genes using bioinformatics tools. To investigate the potential target gene Thbs1, we utilized lens-induced myopia models in male C57BL/6J mice and performed Western blot analysis to detect the expression level of scleral THBS1 during myopia development. Additionally, we evaluated the effects of scleral THBS1 knockdown on myopia development through AAV sub-Tenon's injection. The refractive status and axial length were measured using a refractometer and SD-OCT system.

RESULTS

During lens-induced myopia, THBS1 protein expression in the sclera was downregulated, particularly in the early stages of myopia induction. Moreover, the mice in the THBS1 knockdown group exhibited alterations in myopia development in both refraction and axial length changed compared to the control group. Western blotting analysis confirmed the effectiveness of AAV-mediated knockdown, demonstrating a decrease in COLA1 expression and an increase in MMP9 levels in the sclera.

CONCLUSION

Our findings indicate that sclera THBS1 levels decreased during myopia development and subsequent THBS1 knockdown showed a decrease in scleral COLA1 expression. Taken together, these results suggest that THBS1 plays a role in maintaining the homeostasis of scleral extracellular matrix, and the reduction of THBS1 may promote the remodeling process and then affect ocular axial elongation during myopia progression.

Cholesterol induction in CD8+ T cell exhaustion in colorectal cancer via the regulation of endoplasmic reticulum-mitochondria contact sites

BACKGROUND

Hypercholesterolemia is one of the risk factors for colorectal cancer (CRC). Cholesterol can participate in the regulation of human T cell function and affect the occurrence and development of CRC.

OBJECTIVE

To elucidate the pathogenesis of CRC immune escape mediated by CD8+ T cell exhaustion induced by cholesterol.

METHODS

CRC samples (n = 217) and healthy individuals (n = 98) were recruited to analyze the relationship between peripheral blood cholesterol levels and the clinical features of CRC. An animal model of CRC with hypercholesterolemia was established. Intraperitoneal intervention with endoplasmic reticulum stress (ERS) inhibitors in hypercholesterolemic CRC mice was performed. CD69, PD1, TIM-3, and CTLA-4 on CD8+ T cells of spleens from C57BL/6 J mice were detected by flow cytometry. CD8+ T cells were cocultured with MC38 cells (mouse colon cancer cell line). The proliferation, apoptosis, migration and invasive ability of MC38 cells were detected by CCK-8 assay, Annexin-V APC/7-AAD double staining, scratch assay and transwell assay, respectively. Transmission electron microscopy was used to observe the ER structure of CD8+ T cells. Western blotting was used to detect the expression of ERS and mitophagy-related proteins. Mitochondrial function and energy metabolism were measured. Immunoprecipitation was used to detect the interaction of endoplasmic reticulum-mitochondria contact site (ERMC) proteins. Immunofluorescence colocalization was used to detect the expression and intracellular localization of ERMC-related molecules.

RESULTS

Peripheral blood cholesterol-related indices, including Tc, low density lipoproteins (LDL) and Apo(a), were all increased, and high density lipoprotein (HDL) was decreased in CRCs. The proliferation, migration and invasion abilities of MC38 cells were enhanced, and the proportion of tumor cell apoptosis was decreased in the high cholesterol group. The expression of IL-2 and TNF-α was decreased, while IFN-γ was increased in the high cholesterol group. It indicated high cholesterol could induce exhaustion of CD8+ T cells, leading to CRC immune escape. Hypercholesterolemia damaged the ER structure of CD8+ T cells and increased the expression of ER stress molecules (CHOP and GRP78), lead to CD8+ T cell exhaustion. The expression of mitophagy-related proteins (BNIP3, PINK and Parkin) in exhausted CD8+ T cells increased at high cholesterol levels, causing mitochondrial energy disturbance. High cholesterol enhanced the colocalization of Fis1/Bap31, MFN2/cox4/HSP90B1, VAPB/PTPIP51, VDAC1/IPR3/GRP75 in ERMCs, indicated that high cholesterol promoted the intermolecular interaction between ER and mitochondrial membranes in CD8+ T cells.

CONCLUSION

High cholesterol regulated the ERS-ERMC-mitophagy axis to induce the exhaustion of CD8+ T cells in CRC.

Establishment of a novel ER-stress induced myopia model in mice

BACKGROUND

Recent studies have indicated a strong correlation between endoplasmic reticulum (ER) stress and myopia and that eyedrops containing the ER stress inducer tunicamycin (Tm) can induce myopic changes in C57BL/6 J mice. Therefore, this study aimed to create a new myopia model using Tm eyedrops and to explore the mechanism of ER stress-mediated myopia development.

METHODS

Three-week-old C57BL/6 J mice were treated with different concentrations (0, 25, 50, and 100 μg/mL) and/or number of applications (zero, one, three, and seven) of Tm eyedrops. Refraction and axial length (AL) were measured before and one week after Tm treatment. Scleral collagen alterations were evaluated under polarised light after picrosirius red staining. ER stress-related indicators, such as the expression of collagen I and cleaved collagen were detected using Western blotting.

RESULTS

Compared with the control group, mice administered eyedrops with 50 μg/mL Tm only once showed the greatest myopic shifts in refraction and AL elongation and reduced scleral expression of collagen I. Picrosirius red staining showed a lower percentage of bundled collagen in the Tm group. Expression of ER-stress indicators increased in the Tm groups. Furthermore, optimised administration of Tm induced matrix metalloproteinase-2 (MMP2) expression in the sclera, which plays a major role in collagen degradation.

CONCLUSIONS

We have demonstrated that ER stress in the sclera is involved in myopia progression. Tm eyedrops induced myopic changes, loosening of the scleral collagen and decreased expression of collagen I. This process may be associated with ER stress in the sclera, which upregulates the expression of MMP2 leading to collagen degradation.

Topical Application of Bunazosin Hydrochloride Suppresses Myopia Progression With an Increase in Choroidal Blood Perfusion

Purpose

The incidence of myopia has rapidly increased in recent decades, making it a growing public health concern worldwide. Interventions to suppress the progression of myopia are needed; one suggested strategy is the prevention of choroidal thinning, which can improve choroidal blood perfusion (ChBP). Bunazosin hydrochloride (BH) is an alpha1-adrenergic blocker and commercialized glaucoma eye drop that increases in blood circulation in the eye. In this study, we evaluated the efficacy of BH in suppressing the progression of myopia in a lens-induced murine model.

Methods

Lens-induced myopia was induced in 3-week-old C57BL/6 J mice with -30 diopter (D) lenses for three weeks. Refractive error, axial length, and choroidal thickness were evaluated at three and six weeks of age using an infrared photorefractor and a spectral domain optical coherence tomography (OCT) system. Moreover, ChBP and scleral thickness were evaluated using swept-source OCT and histological analysis.

Results

Compared with the controls, the administration of BH eye drops suppressed the myopic shift of refractive error (mean difference ± standard error in the eye with -30 D lens, -13.65 ± 5.69 D vs. 2.55 ± 4.30 D; P < 0.001), axial elongation (0.226 ± 0.013 mm vs. 0.183 ± 0.023 mm; P < 0.05), choroidal thinning (-2.01 ± 1.80 µm vs. 1.88 ± 1.27 µm; P < 0.001), and scleral thinning (11.41 ± 3.91 µm vs. 19.72 ± 4.01 µm; P < 0.01) with myopia progression and increased ChBP (52.0% ± 4.1% vs. 59.5% ± 6.3%; P < 0.05). The suppressive effect of BH eye drops was dose-dependent and higher than that of other glaucoma eye drops and alpha1 blockers.

Conclusions

These results demonstrate the potential of BH eye drops in the treatment of myopia and support further investigation of their efficacy in humans. Further studies are needed to determine the mechanism of action and long-term safety of this treatment.

Sonodynamic Therapy of NRP2 Monoclonal Antibody-Guided MOFs@COF Targeted Disruption of Mitochondrial and Endoplasmic Reticulum Homeostasis to Induce Autophagy-Dependent Ferroptosis

The lethality and chemotherapy resistance of pancreatic cancer necessitates the urgent development of innovative strategies to improve patient outcomes. To address this issue, we designed a novel drug delivery system named GDMCN2,which uses iron-based metal organic framework (Fe-MOF) nanocages encased in a covalent organic framework (COF) and modified with the pancreatic cancer-specific antibody, NRP2. After being targeted into tumor cells, GDMCN2 gradually release the sonosensitizer sinoporphyrin sodium (DVDMS) and chemotherapeutic gemcitabine (GEM) and simultaneously generated reactive oxygen species (ROS) under ultrasound (US) irradiation. This system can overcome gemcitabine resistance in pancreatic cancer and reduce its toxicity to non-targeted cells and tissues. In a mechanistic cascade, the release of ROS activates the mitochondrial transition pore (MPTP), leading to the release of Ca2+ and induction of endoplasmic reticulum (ER) stress. Therefore, microtubule-associated protein 1A/1B-light chain 3 (LC3) is activated, promoting lysosomal autophagy. This process also induces autophagy-dependent ferroptosis, aided by the upregulation of Nuclear Receptor Coactivator 4 (NCOA4). This mechanism increases the sensitivity of pancreatic cancer cells to chemotherapeutic drugs and increases mitochondrial and DNA damage. The findings demonstrate the potential of GDMCN2 nanocages as a new avenue for the development of cancer therapeutics.

Endoplasmic reticulum stress: molecular mechanism and therapeutic targets

The endoplasmic reticulum (ER) functions as a quality-control organelle for protein homeostasis, or "proteostasis". The protein quality control systems involve ER-associated degradation, protein chaperons, and autophagy. ER stress is activated when proteostasis is broken with an accumulation of misfolded and unfolded proteins in the ER. ER stress activates an adaptive unfolded protein response to restore proteostasis by initiating protein kinase R-like ER kinase, activating transcription factor 6, and inositol requiring enzyme 1. ER stress is multifaceted, and acts on aspects at the epigenetic level, including transcription and protein processing. Accumulated data indicates its key role in protein homeostasis and other diverse functions involved in various ocular diseases, such as glaucoma, diabetic retinopathy, age-related macular degeneration, retinitis pigmentosa, achromatopsia, cataracts, ocular tumors, ocular surface diseases, and myopia. This review summarizes the molecular mechanisms underlying the aforementioned ocular diseases from an ER stress perspective. Drugs (chemicals, neurotrophic factors, and nanoparticles), gene therapy, and stem cell therapy are used to treat ocular diseases by alleviating ER stress. We delineate the advancement of therapy targeting ER stress to provide new treatment strategies for ocular diseases.

CCL2-mediated inflammatory pathogenesis underlies high myopia-related anxiety

High myopia is a leading cause of blindness worldwide. It may lead to emotional defects that rely closely on the link between visual sensation and the central nervous system. However, the extent of the defects and its underlying mechanism remain unknown. Here, we report that highly myopic patients exhibit greater anxiety, accompanied by higher CC chemokine ligand 2 (CCL2) and monocyte levels in the blood. Similar findings are found in the mouse model of high myopia. Mechanistic evaluations using GFP-positive bone marrow chimeric mice, parabiotic mouse model, enhanced magnetic resonance imaging, etc., show that highly myopic visual stimulation increases CCL2 expression in eyes, aggravates monocyte/macrophage infiltration into eyes and brains, and disrupts blood-ocular barrier and blood-brain barrier of mice. Conversely, Ccl2-deficient highly myopic mice exhibit attenuated ocular and brain infiltration of monocytes/macrophages, reduced disruption of the blood-ocular barrier and blood-brain barrier, and less anxiety. Substantial alleviation of high myopia-related anxiety can also be achieved with the administration of CCL2-neutralizing antibodies. Our results establish the association between high myopia and anxiety, and implicate the CCL2-mediated inflammatory pathogenesis as an underlying mechanism.

Changes in Expression in BMP2 and Two Closely Related Genes in Guinea Pig Retinal Pigment Epithelium during Induction and Recovery from Myopia

PURPOSE

We previously reported differential gene expression of the bone morphogenetic protein 2 (Bmp2) in guinea pig retinal pigment epithelium (RPE) after 1 day of hyperopic defocus, imposed with a negative contact lens (CLs). The study reported here sought to obtain insights into the temporal profiles of gene expression changes in Bmp2, as well as those of two closely related genes, the inhibitor of DNA binding 3 (Id3) and Noggin (Nog), both during myopia induction and when the CL treatment was terminated to allow recovery from induced myopia.

METHODS

To induce myopia, 2-week-old pigmented guinea pigs (New Zealand strain, n = 8) wore monocular -10 diopter (D) rigid gas-permeable (RGP) CLs for one week, while the other eye served as a control. Ocular measurements were made at baseline, 3 days, and 7 days after the initiation of CL wear, with treatment then being terminated and additional measurements being made after a further 3 days, 1 week, and 2 weeks. Spherical equivalent refractive errors (SERs), axial length (AL), choroidal thickness (ChT), and scleral thickness (ScT) data were collected using retinoscopy, optical biometry (Lenstar), and spectral domain optical coherence tomography (SD-OCT), respectively. RPE samples were collected from both eyes of the guinea pigs after either 1 day or 1 week of CL wear or 1 day or 2 weeks after its termination, and RNA was subsequently isolated and subjected to quantitative real-time PCR (qRT-PCR) analyses, targeting the Bmp2, Id3, and Nog genes.

RESULTS

Mean interocular differences (treated-control) in AL and SER were significantly different from baseline after 3 and 7 days of CL wear, consistent with induced myopia (p < 0.001 for all cases). Termination of CL wear resulted in the normalization (i.e., recovery) of the ALs and SERs of the treated eyes within 7 days, and the earlier significant ChT thinning with CL wear (p = 0004, day 7) was replaced by rapid thickening, which remained significant on day 7 (p = 0.009) but had normalized by day 14. The ChT changes were much smaller in magnitude than the AL changes in both phases. Interocular differences in the ScT showed no significant changes. The Bmp2 and Id3 genes were both significantly downregulated with CL wear, after 1 day (p = 0.012 and 0.016) and 7 days (p = 0.002 and 0.005), while Bmp2 gene expression increased and Nog gene expression decreased after the termination of CL wear, albeit transiently, which was significant on 1 day (p = 0.004 and 0.04) but not 2 weeks later. No change in Id3 gene expression was observed over the latter period. Conclusions: The above patterns of myopia induction and recovery validate this negative RGP-CL model as an alternative to traditional spectacle lens models for guinea pigs. The defocus-driven, sign-dependent changes in the expression of the Bmp2 gene in guinea pig RPE are consistent with observations in chicks and demonstrate the important role of BMP2 in eye growth regulation.

Bisphenol A exposure triggers endoplasmic reticulum stress pathway leading to ocular axial elongation in mice

Background

Ocular axial elongation is one of the features of myopia progression. Endoplasmic reticulum (ER) stress-associated scleral remodeling plays an important role in ocular axial elongation. Bisphenol A (BPA) is one of the most common environmental pollutants and is known to affect various human organs through ER stress. However, whether BPA exerts an effect on scleral remodeling remains unknown. The purpose of this study was to determine the effect of BPA on the development of myopia and scleral ER stress.

Methods

BPA was administered by intraperitoneal injection. 4-PBA was administered as an endoplasmic reticulum stress inhibitor by eye drops. Refraction and axial length were measured by refractometer and SD-OCT system. Western blot was performed to detect the expression level of ER stress-related proteins.

Results

BPA-administered mice exhibit axial elongation and myopic refractive shift with endoplasmic reticulum stress in the sclera. BPA administration activated scleral PERK and ATF6 pathways, and 4-PBA eye drops attenuated ER stress response and suppressed myopia progression.

Conclusion

BPA controlled axial elongation during myopia development in a mouse model by inducing scleral ER stress and activation of the PERK/ATF6 pathway. 4-PBA eye drops as ER stress inhibitor suppressed BPA-induced myopia development.