Experimental eye research最新文献

Thyroid eye disease (TED) is characterized by fibroblast-driven inflammation and extracellular matrix expansion, which contribute to orbital congestion and proptosis. Platelet-derived growth factor-β (PDGFβ) promotes hyaluronan (HA) synthesis and cytokine production in orbital fibroblasts (OFs); however, whether metabolic modulation can counteract this pathway is unknown. We tested whether metformin, an indirect activator of AMP-activated protein kinase (AMPK), attenuates PDGFβ signaling in TED OFs. Primary OFs from 14 TED and 4 non-TED donors were treated with PDGFβ with or without metformin or the direct AMPK activator 5-aminoimidazole-4-carboxamide ribonucleotide (AICAR). PDGFβ elicited markedly greater HA and cytokine responses in TED OFs than in non-TED OFs and suppressed AMPK phosphorylation. Metformin treatment restored AMPK phosphorylation, reduced HA accumulation (∼2.3-3.1-fold), and decreased IL-6 and IL-8 production. AICAR produced similar AMPK-dependent effects. Mechanistically, metformin attenuated PDGFβ-driven activation of the phosphoinositide 3-kinase (PI3K)-AKT-forkhead box O1 (FoxO1)-nuclear factor kappa B (NF-κB) axis, a pro-inflammatory and pro-survival cascade. These data identify PDGFβ-mediated AMPK suppression as a pathogenic mechanism in TED fibroblasts and demonstrate that AMPK reactivation reduces pro-fibrotic and inflammatory signals. Together, these findings support the therapeutic repurposing of metformin in TED.

Background: As the predominant cause of blindness, cataract pathogenesis centrally involves oxidative stress-induced damage and apoptosis in lens epithelial cells. Although resveratrol possesses recognized antioxidant and antiapoptotic activities, its functional role in cataract development and its specific impact on TXNIP require further elucidation. This study aimed to investigate whether resveratrol delays cataract progression by regulating the TXNIP/Trx2 pathway, improving mitochondrial function, and inhibiting apoptosis.

Methods: In vitro, an oxidative stress model was established using the hydrogen peroxide (H₂O₂)-induced human lens epithelial cell line B3 (HLE-B3), whereas in vivo, a cataract model was constructed in sodium selenite-induced SD rats. Evaluations included cell viability, ROS levels, mitochondrial function (mitoROS and ΔΨm), antioxidant markers (GSH, SOD, and CAT), expression of TXNIP, Trx2, and apoptosis-related proteins (cleaved-caspase-3, Bax, Bcl-2), and apoptosis detection. Lenticular opacity and histopathological changes were assessed in vivo.

Results: In vitro experiments demonstrated that resveratrol and SRI37330 comparably suppressed H₂O₂-induced TXNIP expression and mitochondrial translocation, thereby upregulating Trx2, reducing ROS production, improving mitochondrial membrane potential, enhancing antioxidant capacity, and attenuating apoptosis. In vivo experiments revealed that resveratrol alleviated lens opacity and tissue abnormalities in rats, restored antioxidant function, regulated the expression of TXNIP, Trx2, and apoptosis-related proteins, and inhibited apoptosis.

Conclusion: Resveratrol delays cataract formation and progression by inhibiting TXNIP expression and mitochondrial translocation, restoring the mitochondrial antioxidant protein Trx2 expression, thereby reducing mitochondrial oxidative stress-related damage and blocking the mitochondrial apoptotic pathway.

Free-living Acanthamoeba can lead to granulomatous amebic encephalitis or Acanthamoeba keratitis (AK), an eye infection. AK is most common among contact lens wearers, and causes include long-term lens use, contamination of the contact lens, and corneal trauma. In vitro studies of AK, especially the development of therapeutic drugs, need to be confirmed by in vivo experiments. We developed our AK mouse model using a variety of methods. A. castellanii (AK/AJ1; 1 × 10⁶ cells) were loaded onto 2 mm contact lens pieces for insertion into the scratched eyes of mice under anesthesia, and the eyelids were sutured. After infection (1 to 14 days), in the daily follow-up, it was observed that the AK lesion had progressed in the mouse eyes, and PCR confirmed the amplification of the Acanthamoeba DNA. This study investigated the effective cultivation method to certify PCR analysis in the AK mouse model. After inoculation at 1, 3, 7, and 14 days, PCR was performed on eyeball samples collected from the AK mouse model. Successful cultivation from homogenized eyeballs of A. castellanii was done in the non-nutrient agar with the lawn of Escherichia coli and scaled up with PYG medium. Furthermore, the PCR products obtained from the amoeba cultured in the AK model showed a match of over 99 % with the genetic information of the inoculated amoeba. We suggest that cultivation and PCR methods can confirm the development of AK in the AK mouse model.

Purpose: This study aimed to investigate the function and diagnostic potential of histone lactylation, specifically H3K18la, in cataract.

Methods: This study enrolled 72 participants, including 36 cataract patients and 36 control volunteers undergoing non-cataract intraocular surgery. Aqueous humor (AH) samples were collected from all subjects. The human lens epithelial cell line SRA01/04 was treated with transforming growth factor (TGF)-β2 to model cataractogenesis. Protein levels of global lactylation and H3K18la were assessed by Western blot. Metabolic activity was evaluated by measuring lactate production and glucose uptake, while oxidative stress was indicated by malondialdehyde levels. Inflammatory cytokine expression was quantified by real-time-quantitative polymerase chain reaction, and the direct binding of H3K18la to the IL-1β promoter was confirmed by chromatin immunoprecipitation-qPCR. The diagnostic value of biomarkers was analyzed using receiver operating characteristic curves.

Results: AH from cataract patients and TGF-β2-treated SRA01/04 cells exhibited elevated levels of global lactylation and H3K18la. ROC analysis demonstrated high potential diagnostic accuracy for both total lactylation and H3K18la in AH samples. Clinically, high H3K18la expression was significantly correlated with older age (≥65 years) and greater cataract severity. In vitro, lactic acid treatment enhanced H3K18la levels and amplified TGF-β2-induced metabolic shifts and oxidative stress. Mechanistically, H3K18la directly bound to the IL-1β promoter and activated its transcription. Finally, IL-1β mRNA was significantly upregulated in patient AH and also showed high potential diagnostic value.

Conclusions: H3K18la-driven transcriptional activation of IL-1β is associated with cataract development. H3K18la and IL-1β in the aqueous humor represent promising and sensitive potential biomarkers for the diagnosis of cataract.

Peroxisomes are a type of organelles essential for metabolic activities. They are extensively distributed in retinal tissue and play a core role in biomolecular synthesis, cellular metabolism, oxidative stress, and immune defense. Patients suffering from peroxisomal disorders will exhibit a number of ocular symptoms, including degenerative retinopathy, cataract, glaucoma, and optic nerve abnormalities. Specifically, pathological stimuli such as oxidative stress, aging-related metabolic decline, genetic mutations, and hyperglycemia induce the decline of peroxisomal biogenesis, coupled with disrupted activity of lipid metabolic enzymes, leading to aberrant peroxisomal function and expression. This impairment further triggers lipid metabolic dysregulation and heightened oxidative stress, which sequentially contribute to the development of degenerative retinopathy. This review comprehensively delves into the functions of peroxisomes in retinal lipid metabolism and reduction-oxidation balance. These findings may help to uncover the exact mechanism through which peroxisomal dysfunction initiates retinal pathologies. Furthermore, emerging therapeutic strategies targeting peroxisomes are also introduced in this review. These strategies can promote the transformation from symptomatic alleviation to mechanistic intervention for organelle dysfunction in degenerative retinopathy. Future studies should concentrate on clarifying the cell-type specific functions of peroxisomes in retina, deciphering the complicated interplay between peroxisomes and other organelles, thereby optimizing the efficiency of peroxisome-targeted therapeutics.