Lens autophagy protein ATG16L1: a potential target for cataract treatment.

Rationale: Cataract is the leading cause of blindness and low vision worldwide, yet its pathological mechanism is not fully understood. Although macroautophagy/autophagy is recognized as essential for lens homeostasis and has shown potential in alleviating cataracts, its precise mechanism remains unclear. Uncovering the molecular details of autophagy in the lens could provide targeted therapeutic interventions alongside surgery. Methods: We monitored autophagic activities in the lens and identified the key autophagy protein ATG16L1 by immunofluorescence staining, Western blotting, and transmission electron microscopy. The regulatory mechanism of ATG16L1 ubiquitination was analyzed by co-immunoprecipitation and Western blotting. We used the crystal structure of E3 ligase gigaxonin and conducted the docking screening of a chemical library. The effect of the identified compound riboflavin was tested in vitro in cells and in vivo animal models. Results: We used HLE cells and connexin 50 (cx50)-deficient cataract zebrafish model and confirmed that ATG16L1 was crucial for lens autophagy. Stabilizing ATG16L1 by attenuating its ubiquitination-dependent degradation could promote autophagy activity and relieve cataract phenotype in cx50-deficient zebrafish. Mechanistically, the interaction between E3 ligase gigaxonin and ATG16L1 was weakened during this process. Leveraging these mechanisms, we identified riboflavin, an E3 ubiquitin ligase-targeting drug, which suppressed ATG16L1 ubiquitination, promoted autophagy, and ultimately alleviated the cataract phenotype in autophagy-related models. Conclusions: Our study identified an unrecognized mechanism of cataractogenesis involving ATG16L1 ubiquitination in autophagy regulation, offering new insights for treating cataracts.

Clinical significance of CTGF and Cry61 protein in extraocular muscles of strabismic patients.

PURPOSE: To investigate the relationship between clinical features and protein amounts of Cysteine-rich 61 (Cyr61/CCN1) and connective tissue growth factor (CTGF/CCN2), which are vital components and regulators of the extracellular matrix in resected muscles from strabismus surgery. METHODS: Strabismus patients who were diagnosed with horizontal concomitant strabismus or inferior oblique overaction (IOOA) and required extraocular muscles (EOMs) resection to correct eye position were included in this study. The protein amounts were measured by enzyme-linked immunosorbent assay (ELISA) in resected EOMs. Multivariable linear regression was used to investigate the associations, adjusting for gender, age (continuous), amblyopia, and disease duration. RESULTS: A total of 141 muscles (including 38 lateral, 81 medial rectus, and 22 inferior oblique muscles) from 128 patients were collected in this study. The amount of Cry61 and CTGF per millimeter was significantly negatively associated with deviation angle in intermittent exotropia patients (Cry61: ß, - 1.44; 95%CI, - 2.79 to - 0.10, p = 0.035; CTGF: ß, - 3.14; 95%CI, - 5.06 to - 1.22, p = 0.002). The same relationship was also detected in the partially accommodative and non-accommodative esotropia patients, although it was not statistically significant (Cry61: ß, - 2.40; 95%CI, - 5.05 to 0.24; p = 0.073; CTGF: ß, - 3.47; 95%CI, - 9.18 to 2.87; p = 0.269). The amount of Cry61 and CTGF per millimeter showed significant associations with the degree of IOOA (p < 0.05). CONCLUSIONS: Taken together, our results demonstrated a significant relationship between deviation angle and protein amount of Cry61 and CTGF and implied that Cry61 and CTGF may play important roles in modulation of EOM contractility, which provide new insights into strabismus pathogenesis.

TP53INP2 Contributes to TGF-ß2-Induced Autophagy during the Epithelial-Mesenchymal Transition in Posterior Capsular Opacification Development.

BACKGROUND: Posterior capsule opacification (PCO) is the most common complication after cataract surgery, in which increased levels of transforming growth factor-beta 2 (TGF-ß2) accelerate PCO formation; however, the pathological mechanisms are not fully understood. This study aims to explore the regulation mechanism of TGF-ß2 in PCO formation via its autophagic functions. METHODS: The autophagic effect of TGF-ß2 was detected by transmission electron microscopy (TEM), Western blotting, and immunofluorescence analysis. The association between autophagy and the epithelial-mesenchymal transition (EMT) was evaluated by qPCR and Western blotting. The transcriptome analysis was used to uncover the molecular mechanism of TGF-ß2-induced PCO formation. RESULTS: TGF-ß2 specifically promotes autophagy flux in human lens epithelial cells. The activation of autophagy by rapamycin can promote EMT marker synthesis and improve cell migration. However, the inhibition of autophagy by 3-MA attenuates EMT. To uncover the molecular mechanisms, we performed RNA sequencing and found that TGF-ß2 elevated tumor protein p53-inducible nuclear protein2 (TP53INP2) expression, which was accompanied by a nuclear-to-cytoplasm translocation. Moreover, the knockdown of TP53INP2 blocked the TGF-ß2-induced autophagy and EMT processes, revealing that TP53INP2 plays an important role in TGF-ß2-induced autophagy during EMT. CONCLUSIONS: Taken together, the results of this study suggested that TP53INP2 was a novel regulator of PCO development by TGF-ß2, and notably, TP53INP2, may be a potential target for the pharmacological treatment of PCO.

Incidence of endophthalmitis after phacoemulsification cataract surgery: a Meta-analysis.

AIM: To evaluate the overall endophthalmitis incidence and the effectiveness of potential prophylaxis measures following phacoemulsification cataract surgery (PCS). METHODS: The PubMed and Web of Science databases were searched from inception to April 30th, 2021. We included studies that reported on the incidence of endophthalmitis following PCS. The quality of the included studies was critically evaluated with the Newcastle-Ottawa quality assessment scale. The random effect or the fixed-effects model was used to evaluated the pooled incidence based on the heterogeneity. The publication bias was assessed by Egger's linear regression and Begg's rank correlation tests. RESULTS: A total of 39 studies containing 5 878 114 eyes were included and critically appraised in the Meta-analysis. For overall incidence of endophthalmitis after PCS, the Meta-analysis yielded a pooled estimate of 0.092% (95%CI: 0.083%-0.101%). The incidence appeared to decrease with time (before 2000: 0.097%, 95%CI: 0.060%-0.135%; 2000 to 2010: 0.089%, 95%CI: 0.076%-0.101%; after 2010: 0.063%, 95%CI: 0.050%-0.077%). Compared with typical povidone-iodine solution (0.178%, 95%CI: 0.071%-0.285%) and antibiotics subconjunctival injections (0.047%, 95%CI: 0.001%-0.095%), the use of intracameral antibiotics significantly reduced the incidence of endophthalmitis after PCS (0.045%, 95%CI: 0.034%-0.055%, RR: 7.942, 95%CI: 4.510-13.985). CONCLUSION: Due to the advancement of phacoemulsification technology and the widespread use of intracameral antibiotics, the incidence of endophthalmitis following PCS shows a decreasing trend over time. The use of intracameral antibiotics administration will significantly reduce the risk of endophthalmitis.