Targeting endothelial glycolytic reprogramming by tsRNA-1599 for ocular anti-angiogenesis therapy.

Rationale: Current treatments for ocular angiogenesis primarily focus on blocking the activity of vascular endothelial growth factor (VEGF), but unfavorable side effects and unsatisfactory efficacy remain issues. The identification of novel targets for anti-angiogenic treatment is still needed. Methods: We investigated the role of tsRNA-1599 in ocular angiogenesis using endothelial cells, a streptozotocin (STZ)-induced diabetic model, a laser-induced choroidal neovascularization model, and an oxygen-induced retinopathy model. CCK-8 assays, EdU assays, transwell assays, and matrigel assays were performed to assess the role of tsRNA-1599 in endothelial cells. Retinal digestion assays, Isolectin B4 (IB4) staining, and choroidal sprouting assays were conducted to evaluate the role of tsRNA-1599 in ocular angiogenesis. Transcriptomic analysis, metabolic analysis, RNA pull-down assays, and mass spectrometry were utilized to elucidate the mechanism underlying angiogenic effects mediated by tsRNA-1599. Results: tsRNA-1599 expression was up-regulated in experimental ocular angiogenesis models and endothelial cells in response to angiogenic stress. Silencing of tsRNA-1599 suppressed angiogenic effects in endothelial cells in vitro and inhibited pathological ocular angiogenesis in vivo. Mechanistically, tsRNA-1599 exhibited little effect on VEGF signaling but could cause reduced glycolysis and NAD+/NADH production in endothelial cells by regulating the expression of HK2 gene through interacting with YBX1, thus affecting endothelial effects. Conclusions: Targeting glycolytic reprogramming of endothelial cells by a tRNA-derived small RNA represents an exploitable therapeutic approach for ocular neovascular diseases.

Dual anti-angiogenic and anti-inflammatory action of tRNA-Cys-5-0007 in ocular vascular disease.

BACKGROUND: Intravitreal injections of angiogenesis inhibitors have proved efficacious in the majority of patients with ocular angiogenesis. However, one-fourth of all treated patients fail to derive benefits from intravitreal injections. tRNA-derived small RNA (tsRNA) emerges as a crucial class of non-coding RNA molecules, orchestrating key roles in the progression of human diseases by modulating multiple targets. Through our prior sequencing analyses and bioinformatics predictions, tRNA-Cys-5-0007 has shown as a potential regulator of ocular angiogenesis. This study endeavors to elucidate the precise role of tRNA-Cys-5-0007 in the context of ocular angiogenesis. METHODS: Quantitative reverse transcription PCR (qRT-PCR) assays were employed to detect tRNA-Cys-5-0007expression. EdU assays, sprouting assays, transwell assays, and Matrigel assays were conducted to elucidate the involvement of tRNA-Cys-5-0007 in endothelial angiogenic effects. STZ-induced diabetic model, OIR model, and laser-induced CNV model were utilized to replicate the pivotal features of ocular vascular diseases and evaluate the influence of tRNA-Cys-5-0007 on ocular angiogenesis and inflammatory responses. Bioinformatics analysis, luciferase activity assays, RNA pull-down assays, and in vitro studies were employed to elucidate the anti-angiogenic mechanism of tRNA-Cys-5-0007. Exosomal formulation was employed to enhance the synergistic anti-angiogenic and anti-inflammatory efficacy of tRNA-Cys-5-0007. RESULTS: tRNA-Cys-5-0007 expression was down-regulated under angiogenic conditions. Conversely, tRNA-Cys-5-0007 overexpression exhibited anti-angiogenic effects in retinal endothelial cells, as evidenced by reduced proliferation, sprouting, migration, and tube formation abilities. In diabetic, laser-induced CNV, and OIR models, tRNA-Cys-5-0007 overexpression led to decreased ocular vessel leakage, inhibited angiogenesis, and reduced ocular inflammation. Mechanistically, these effects were attributed to the targeting of vascular endothelial growth factor A (VEGFA) and TGF-ß1 by tRNA-Cys-5-0007. The utilization of an exosomal formulation further potentiated the synergistic anti-angiogenic and anti-inflammatory efficacy of tRNA-Cys-5-0007. CONCLUSIONS: Concurrent targeting of tRNA-Cys-5-0007 for anti-angiogenic and anti-inflammatory therapy holds promise for enhancing the effectiveness of current anti-angiogenic therapy.

Comprehensive metabolic profiling of diabetic retinopathy.

Diabetic retinopathy (DR) is an important complication of diabetes mellitus and a prevalent blind-causing ophthalmic disease. Despite years of efforts, rapid and accurate diagnosis of DR remains a challenging task. Metabolomics has been used as a diagnostic tool for disease progression and therapy monitoring. In this study, retinal tissues were collected from diabetic mice and age-matched non-diabetic mice. An unbiased metabolic profiling was performed to identify the altered metabolites and metabolic pathways in DR. 311 differential metabolites were identified between diabetic retinas and non-diabetic retinas under the criteria of variable importance in projection (VIP) > 1 and P < 0.05. These differential metabolites were highly enriched in purine metabolism, amino acid metabolism, glycerophospholipid metabolism, and pantaothenate and CoA biosynthesis. We then evaluated the sensitivity and specificity of purine metabolites as the candidate biomarkers for DR through the area under the receiver-operating characteristic curves (AUC-ROCs). Compared with other purine metabolites, adenosine, guanine, and inosine had higher sensitivity, specificity, and accuracy for DR prediction. In conclusion, this study sheds new light on the metabolic mechanism of DR, which can facilitate clinical diagnosis, therapy, and prognosis of DR in the future.

A Joint Model for Macular Edema Analysis in Optical Coherence Tomography Images Based on Image Enhancement and Segmentation.

Optical coherence tomography (OCT) provides the visualization of macular edema which can assist ophthalmologists in the diagnosis of ocular diseases. Macular edema is a major cause of vision loss in patients with retinal vein occlusion (RVO). However, manual delineation of macular edema is a laborious and time-consuming task. This study proposes a joint model for automatic delineation of macular edema in OCT images. This model consists of two steps: image enhancement using a bioinspired algorithm and macular edema segmentation using a Gaussian-filtering regularized level set (SBGFRLS) algorithm. We then evaluated the delineation efficiency using the following parameters: accuracy, precision, sensitivity, specificity, Dice's similarity coefficient, IOU, and kappa coefficient. Compared with the traditional level set algorithms, including C-V and GAC, the proposed model had higher efficiency in macular edema delineation as shown by reduced processing time and iteration times. Moreover, the accuracy, precision, sensitivity, specificity, Dice's similarity coefficient, IOU, and kappa coefficient for macular edema delineation could reach 99.7%, 97.8%, 96.0%, 99.0%, 96.9%, 94.0%, and 96.8%, respectively. More importantly, the proposed model had comparable precision but shorter processing time compared with manual delineation. Collectively, this study provides a novel model for the delineation of macular edema in OCT images, which can assist the ophthalmologists for the screening and diagnosis of retinal diseases.

Role of METTL3-Dependent N6-Methyladenosine mRNA Modification in the Promotion of Angiogenesis.

Epigenetic alterations occur in many physiological and pathological processes. N6-methyladenosine (m6A) modification is the most prevalent modification in eukaryotic mRNAs. However, the role of m6A modification in pathological angiogenesis remains elusive. In this study, we showed that the level of m6A modification was significantly upregulated in endothelial cells and mouse retinas following hypoxic stress, which was caused by increased METTL3 levels. METTL3 silencing or METTL3 overexpression altered endothelial cell viability, proliferation, migration, and tube formation in vitro. METTL3 knockout in vivo decreased avascular area and pathological neovascular tufts in an oxygen-induced retinopathy model and inhibited alkali burn-induced corneal neovascularization. Mechanistically, METTL3 exerted its angiogenic role by regulating Wnt signaling through the m6A modification of target genes (e.g., LRP6 and dishevelled 1 [DVL1]). METTL3 enhanced the translation of LRP6 and DVL1 in an YTH m6A RNA-binding protein 1 (YTHDF1)-dependent manner. Collectively, this study suggests that METTL3-mediated m6A modification is an important hypoxic stress-response mechanism. The targeting of m6A through its writer enzyme METTL3 is a promising strategy for the treatment of angiogenic diseases.

Circular RNA-ZBTB44 regulates the development of choroidal neovascularization.

Rationale: Choroidal neovascularization (CNV) is a major cause of severe vision loss and occurs in many ocular diseases, especially neovascular age-related macular degeneration (nAMD). Circular RNAs (circRNAs) are emerging as a new class of endogenous noncoding RNAs, which have been implicated in the regulation of endothelial cell dysfunction in diabetes mellitus and cancer. In this study, we aimed to determine the role of circRNA-ZBTB44 (cZBTB44) in the pathogenesis of CNV. Methods: Quantitative polymerase chain reaction was conducted to detect cZBTB44 expression pattern during CNV development. Isolectin B4 staining, hematoxylin and eosin (HE) staining, and choroidal sprouting assay ex vivo were conducted to evaluate the role of cZBTB44 in the development of CNV. Endothelial cell proliferation, migration and tube formation assays were conducted to determine the role of cZBTB44 in angiogenic effect in vitro. Bioinformatics analysis, RNA immunoprecipitation assay, luciferase assay, and in vitro studies were conducted to investigate the mechanism of cZBTB44-mediated CNV development. Results: cZBTB44 expression was significantly up-regulated in a laser-induced CNV mouse model in vivo and in endothelial cells upon hypoxia stress in vitro. cZBTB44 silencing retarded CNV development, while overexpression of cZBTB44 showed the opposite effects. The role of cZBTB44 in CNV development was confirmed in choroidal sprouting assay ex vivo. cZBTB44 silencing reduced endothelial cell viability, proliferation, migration and tube formation in vitro. cZBTB44 acted as miR-578 sponge to sequester and inhibit miR-578 activity, which led to increased expression of vascular endothelial growth factor A (VEGFA) and vascular cell adhesion molecule-1 (VCAM1). Overexpression of miR-578 mimicked cZBTB44 silencing-mediated anti-angiogenic effects in vivo and in vitro. Furthermore, dysregulated cZBTB44 expression was detected in the clinical samples of nAMD patients. Conclusions: This study provided novel insights into the molecular pathogenesis of CNV. The cZBTB44-miR-578-VEGFA/VCAM1 axis might be a potential source of novel therapeutic targets for neovascularization-related diseases.

Comprehensive circular RNA profiling of proliferative vitreoretinopathy and its clinical significance.

Proliferative vitreoretinopathy (PVR) is one of the major challenges in retinal surgery, which occurs in the patient with complex retinal surgery or penetrating eye injury. Circular RNAs (circRNAs) have emerged as important regulators in many biological processes and disease development. However, the characterization and function of circRNAs in PVR remains elusive. In this study, we identified 91 dysregulated circRNAs in the epiretinal membranes (ERMs) of PVR patients. We further investigated the expression pattern of circ_0043144. circ_0043144 was significantly up-regulated in the vitreous samples and the corresponding serum samples of the patients with PVR. circ_0043144 expression was significantly down-regulated after PVR operation. In vitro studies revealed that circ_0043144 was involved in the regulation of the proliferation, migration and secretion ability of ARPE-19 cells, which is critical for ERM formation. Collectively, this study indicates that circRNAs are potential regulators of the pathogenesis of PVR. circ_0043144 is a promising prognostic and diagnostic indicator for PVR diseases.

Genome-Wide Identification of Circular RNAs as a Novel Class of Putative Biomarkers for an Ocular Surface Disease.

BACKGROUND/AIMS: Pterygium is a common ocular surface disease with an unknown etiology and threatens vision as it invades into the cornea. Circular RNAs (circRNAs) are a novel class of RNA transcripts that participate in several physiological and pathological processes. However, the role of circRNAs in pathogenesis of pterygium remains largely unknown. METHODS: Genome-wide circRNA expression profiling was performed to identify pterygium -related circRNAs. GO analysis, pathway analysis, and miRNA response elements analysis was performed to predict the function of differentially expressed circRNAs in pterygium. MTT assays, Ki67 staining, Transwell assay, Hoechst 33342 staining, and Calcein-AM/PI staining were performed to determine the effect of circRNA silencing on pterygium fibroblast and epithelial cell function. RESULTS: Approximately 669 circRNAs were identified to be abnormally expressed in pterygium tissues. GO analysis demonstrated that the host genes of differentially expressed circRNAs were targeted to extracellular matrix organization (ontology: biological process), cytoplasm (ontology: cellular component), and protein binding (ontology: molecular function). Pathway analysis showed that dysregulated circRNAs-mediated regulatory networks were mostly enriched in focal adhesion signaling pathway. Notably, circ_0085020 (circ-LAPTM4B) was shown as a potential biomarker for pterygium. circ_0085020 (circ-LAPTM4B) silencing affected the viability, proliferation, migration, and apoptosis of pterygium fibroblast and epithelial cells in vitro. CONCLUSIONS: This study provides evidence that circRNAs are involved in the pathogenesis of pterygium and might constitute promising targets for the therapeutic intervention of pterygium.

Targeting circular RNA-ZRANB1 for therapeutic intervention in retinal neurodegeneration.

Glaucoma is a neurodegenerative disease characterized by retinal ganglion cell (RGC) loss, optic disc excavation, and progressive visual field loss. Direct or indirect ameliorating retinal neurodegeneration is a promising therapeutic therapy for glaucoma. Circular RNAs (circRNAs) are a class of covalently closed circular RNA transcripts and have emerged as potential regulators in several neurodegenerative diseases. In this study, we show that cZRANB1 expression is significantly upregulated in retinal neurodegeneration induced by glaucoma. cZRANB1 knockdown decreases retinal reactive gliosis, glial cell activation, and facilitates RGC survival in vivo. cZRANB1 knockdown directly regulates Müller cell function and indirectly regulates RGC function in vitro. cZRANB1 acts as miRNA sponge to regulate Müller cell function through cZRANB1/miR-217/RUNX2 network. Intervention of cZRANB1 expression would become an effective strategy for treating retinal neurodegeneration.

Long non-coding RNA MEG3 silencing protects against light-induced retinal degeneration.

Excessive light exposure leads to retinal degeneration and accelerates the progression and severity of several ocular diseases, such as age-related macular degeneration (AMD) and retinitis pigmentosa. Long non-coding RNAs (LncRNAs) have emerged as important regulators of photoreceptor development and ocular diseases. In this study, we investigated the role of lncRNA-MEG3 in light-induced retinal degeneration. MEG3 expression was significantly up-regulated after light insult in vivo and in vitro. MEG3 silencing protected against light-induced retinal degeneration in vivo and light-induced photoreceptor cell apoptosis in vitro. Mechanistically, MEG3 regulated retinal photoreceptor cell function by acting as p53 decoy. MEG3 silencing decreased caspase 3/7 activity, up-regulated anti-apoptotic protein (Bcl-2) expression, and down-regulated pro-apoptotic protein (Bax) expression. Taken together, this study provides a promising method of MEG3 silencing for treating light-induced retinal degeneration.

Ginsenoside Rh2 inhibits vascular endothelial growth factor-induced corneal neovascularization.

VEGF-induced neovascularization plays a pivotal role in corneal neovascularization (CoNV). The current study investigated the potential effect of ginsenoside Rh2 (GRh2) on neovascularization. In HUVECs, pretreatment with GRh2 largely attenuated VEGF-induced cell proliferation, migration, and vessel-like tube formation in vitro. At the molecular level, GRh2 disrupted VEGF-induced VEGF receptor 2 (VEGFR2)-Grb-2-associated binder 1 (Gab1) association in HUVECs, causing inactivation of downstream AKT and ERK signaling. Gab1 knockdown (by targeted short hairpin RNA) similarly inhibited HUVEC proliferation and migration. Notably, GRh2 was ineffective against VEGF in Gab1-silenced HUVECs. In a mouse cornea alkali burn model, GRh2 eyedrops inhibited alkali-induced neovascularization and inflammatory cell infiltrations in the cornea. Furthermore, alkali-induced corneal expression of mRNAs/long noncoding RNAs in cornea were largely attenuated by GRh2. Overall, GRh2 inhibits VEGF-induced angiogenic effect via inhibiting VEGFR2-Gab1 signaling in vitro. It also alleviates angiogenic and inflammatory responses in alkali burn-treated mouse corneas.-Zhang, X.-P., Li, K.-R., Yu, Q., Yao, M.-D., Ge, H.-M., Li, X.-M., Jiang, Q., Yao, J., Cao, C. Ginsenoside Rh2 inhibits vascular endothelial growth factor-induced corneal neovascularization.

Silencing Of Circular RNA-ZNF609 Ameliorates Vascular Endothelial Dysfunction.

Vascular dysfunction is a hallmark of ischemic, cancer, and inflammatory diseases, contributing to disease progression. Circular RNAs (circRNAs) are endogenous non-coding RNAs, which have been reported to be abnormally expressed in many human diseases. In this study, we used retinal vasculature to determine the role of circular RNA in vascular dysfunction. We revealed that cZNF609 was significantly up-regulated upon high glucose and hypoxia stress in vivo and in vitro. cZNF609 silencing decreased retinal vessel loss and suppressed pathological angiogenesis in vivo. cZNF609 silencing increased endothelial cell migration and tube formation, and protected endothelial cell against oxidative stress and hypoxia stress in vitro. By contrast, transgenic overexpression of cZNF609 showed an opposite effects. cZNF609 acted as an endogenous miR-615-5p sponge to sequester and inhibit miR-615-5p activity, which led to increased MEF2A expression. MEF2A overexpression could rescue cZNF609 silencing-mediated effects on endothelial cell migration, tube formation, and apoptosis. Moreover, dysregulated cZNF609 expression was detected in the clinical samples of the patients with diabetes, hypertension, and coronary artery disease. Intervention of cZNF609 expression is promising therapy for vascular dysfunction.

Piezo2 protein: A novel regulator of tumor angiogenesis and hyperpermeability.

Angiogenesis is important for invasive tumor growth and metastasis. Its inhibition is a promising tactic for limiting tumor progression. Here, we showed that Piezo2 knockdown led to decreased glioma angiogenesis and reduced vascular hyperpermeability. Piezo2 was highly expressed in tumor endothelial cells, and its knockdown suppressed vascular leakage and tumor angiogenesis. In a retinal vasculature development assay, corneal angiogenesis assay and a modified Miles assay, Piezo2 knockdown obviously decreased angiogenesis and vascular hyperpermeability. In vitro assays revealed that Piezo2 knockdown inhibited endothelial cell proliferation, migration, and tube formation. Moreover, In vitro co-culture system assay showed that Piezo2 knockdown in endothelial cells suppressed cell proliferation, migration, and invasion of glioma tumor cells. Piezo2 could regulate glioma angiogenesis via Ca2+/Wnt11/ß-catenin signaling in endothelial cells. Taken together, these studies provide the evidence for Piezo2 as a critical regulator of tumor angiogenesis and vascular permeability.

3H-1,2-dithiole-3-thione protects retinal pigment epithelium cells against Ultra-violet radiation via activation of Akt-mTORC1-dependent Nrf2-HO-1 signaling.

Excessive UV radiation and reactive oxygen species (ROS) cause retinal pigment epithelium (RPE) cell injuries. Nrf2 regulates transcriptional activation of many anti-oxidant genes. Here, we tested the potential role of 3H-1,2-dithiole-3-thione (D3T) against UV or ROS damages in cultured RPE cells (both primary cells and ARPE-19 line). We showed that D3T significantly inhibited UV-/H2O2-induced RPE cell death and apoptosis. UV-stimulated ROS production was dramatically inhibited by D3T pretreatment. D3T induced Nrf2 phosphorylation in cultured RPE cells, causing Nrf2 disassociation with KEAP1 and its subsequent nuclear accumulation. This led to expression of antioxidant response elements (ARE)-dependent gene heme oxygenase-1 (HO-1). Nrf2-HO-1 activation was required for D3T-mediated cytoprotective effect. Nrf2 shRNA knockdown or S40T dominant negative mutation as well as the HO-1 inhibitor Zinc protoporphyrin (ZnPP) largely inhibited D3T's RPE cytoprotective effects against UV radiation. Yet, exogenous overexpression Nrf2 enhanced D3T's activity in RPE cells. Further studies showed that D3T activated Akt/mTORC1 in cultured RPE cells. Akt-mTORC1 inhibitors, or Akt1 knockdown by shRNA, not only inhibited D3T-induced Nrf2-HO-1 activation, but also abolished the RPE cytoprotective effects. In vivo, D3T intravitreal injection protected from light-induced retinal dysfunctions in mice. Thus, D3T protects RPE cells from UV-induced damages via activation of Akt-mTORC1-Nrf2-HO-1 signaling axis.

Identification of corneal neovascularization-related long noncoding RNAs through microarray analysis.

PURPOSE: To reveal the role of long noncoding RNAs (lncRNAs) in corneal neovascularization (CN). METHODS: We established a murine CN model and performed lncRNA expression profiling to identify differentially expressed lncRNAs between normal and vascularized corneas. Based on Pearson correlation analysis, an lncRNA/mRNA coexpression network was constructed. Gene ontology (GO) enrichment and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses of lncRNA-coexpressed mRNAs were conducted to determine the related biological modules and pathological pathways. Real-time polymerase chain reactions were carried out to detect the expression pattern of lncRNA in the clinical samples. RESULTS: A total of 154 differentially expressed lncRNAs were identified between vascularized and normal corneas, including 60 downregulated lncRNAs and 94 upregulated lncRNAs. GO enrichment analysis of lncRNA-coexpressed mRNAs indicated that the biological modules were correlated with extracellular region, DNA binding, and immune response. KEGG pathway analysis indicated that "pathways in cancer" was the most enriched signaling pathway. Moreover, the human ortholog of NR_033585 and lincRNA:chr8:129102060-129109035 reverse strand was found to be differentially expressed between vascularized and avascular corneas. CONCLUSIONS: This study provides a novel insight into CN pathogenesis. The intervention of dysregulated lncRNAs may become potential targets for the prevention and treatment of ocular vascular diseases.

lncRNA-MIAT regulates microvascular dysfunction by functioning as a competing endogenous RNA.

RATIONALE: Pathological angiogenesis is a critical component of diseases, such as ocular disorders, cancers, and atherosclerosis. It is usually caused by the abnormal activity of biological processes, such as cell proliferation, cell motility, immune, or inflammation response. Long noncoding RNAs (lncRNAs) have emerged as critical regulators of these biological processes. However, the role of lncRNA in diabetes mellitus-induced microvascular dysfunction is largely unknown. OBJECTIVE: To elucidate whether lncRNA-myocardial infarction-associated transcript (MIAT) is involved in diabetes mellitus-induced microvascular dysfunction. METHODS AND RESULTS: Using quantitative polymerase chain reaction, we demonstrated increased expression of lncRNA-MIAT in diabetic retinas and endothelial cells cultured in high glucose medium. Visual electrophysiology examination, TUNEL staining, retinal trypsin digestion, vascular permeability assay, and in vitro studies revealed that MIAT knockdown obviously ameliorated diabetes mellitus-induced retinal microvascular dysfunction in vivo, and inhibited endothelial cell proliferation, migration, and tube formation in vitro. Bioinformatics analysis, luciferase assay, RNA immunoprecipitation, and in vitro studies revealed that MIAT functioned as a competing endogenous RNA, and formed a feedback loop with vascular endothelial growth factor and miR-150-5p to regulate endothelial cell function. CONCLUSIONS: This study highlights the involvement of lncRNA-MIAT in pathological angiogenesis and facilitates the development of lncRNA-directed diagnostics and therapeutics against neovascular diseases.

Aquaporin-4 mitigates retrograde degeneration of rubrospinal neurons by facilitating edema clearance and glial scar formation after spinal cord injury in mice.

Atrophy of upper motor neurons hampers axonal regeneration and functional recovery following spinal cord injury (SCI). Apart from the severity of primary injury, a series of secondary pathological damages including spinal cord edema and glial scar formation affect the fate of injured upper motor neurons. The aquaporin-4 (AQP4) water channel plays a critical role in water homeostasis and migration of astrocytes in the central nervous system, probably offering a new therapeutic target for protecting against upper motor neuron degeneration after SCI. To test this hypothesis, we examined the effect of AQP4 deficiency on atrophy of rubrospinal neurons after unilateral rubrospinal tract transection at the fourth cervical level in mice. AQP4 gene knockout (AQP4-/-) mice exhibited high extent of spinal cord edema at 72 h after lesion compared with wild-type littermates. AQP4-/- mice showed impairments in astrocyte migration toward the transected site with a greater lesion volume at 1 week after surgery and glial scar formation with a larger cyst volume at 6 weeks. More severe atrophy and loss of axotomized rubrospinal neurons as well as axonal degeneration in the rubrospinal tract rostral to the lesion were observed in AQP4-/- mice at 6 weeks after SCI. AQP4 expression was downregulated at the lesioned spinal segment at 3 days and 1 week after injury, but upregulated at 6 weeks. These results demonstrated that AQP4 not only mitigates spinal cord damage but also ameliorates retrograde degeneration of rubrospinal neurons by promoting edema clearance and glial scar formation after laceration SCI. This finding supports the notion that AQP4 may be a promising therapeutic target for SCI.

Epigallocatechin-gallate (EGCG) regulates autophagy in human retinal pigment epithelial cells: a potential role for reducing UVB light-induced retinal damage.

Autophagy is an intracellular catabolic process involved in protein and organelle degradation via the lysosomal pathway that has been linked in the pathogenesis of age-related macular degeneration (AMD). UVB irradiation-mediated degeneration of the macular retinal pigment epithelial (RPE) cells is an important hallmark of AMD, which is along with the change in RPE autophagy. Thus, pharmacological manipulation of RPE autophagy may offer an alternative therapeutic target in AMD. Here, we found that epigallocatechin-3-gallate (EGCG), a polyphenolic compound from green tea, plays a regulatory role in UVB irradiation-induced autophagy in RPE cells. UVB irradiation results in a marked increase in the amount of LC3-II protein in a dose-dependent manner. EGCG administration leads to a significant reduction in the formation of LC3-II and autophagosomes. mTOR signaling activation is required for EGCG-induced LC3-II formation, as evidenced by the fact that EGCG-induced LC3-II formation is significantly impaired by rapamycin administration. Moreover, EGCG significantly alleviates the toxic effects of UVB irradiation on RPE cells in an autophagy-dependent manner. Collectively, our study reveals a novel role of EGCG in RPE autophagy. EGCG may be exploited as a potential therapeutic reagent for the treatment of pathological conditions associated with abnormal autophagy.