Transfer RNA derived fragment, tRF-Glu-CTC, aggravates the development of neovascular age-related macular degeneration.

Rationale: Angiogenesis expedites tissue impairment in many diseases, including age-related macular degeneration (AMD), a leading cause of irreversible blindness in elderly. A substantial proportion of neovascular AMD patients, characterized by aberrant choroidal neovascularization (CNV), exhibit poor responses or adverse reactions to anti-VEGF therapy. Herein, we aimed to unveil the function of newly identified transfer RNA-derived small RNA, tRF-Glu-CTC, in the pathology of CNV and determine its potential in inhibiting angiogenesis. Methods: Small non-coding RNA sequencing and quantitative polymerase chain reaction were conducted to detect expression pattern of tRF-Glu-CTC in CNV development. Immunofluorescence staining, fundus fluorescein angiography and ex vivo choroidal sprouting assays were employed for the evaluation of tRF-Glu-CTC's function in CNV development. The role of tRF-Glu-CTC in endothelial cells were determined by in vitro endothelial cell proliferation, migration and tube formation assays. Transcriptome sequencing, dual-luciferase reporter assay and in vitro experiments were conducted to investigate downstream mechanism of tRF-Glu-CTC mediated pathology. Results: tRF-Glu-CTC exhibited substantial up-regulation in AMD patients, laser-induced CNV model, and endothelial cells under hypoxia condition, which is a hallmark of CNV. Inhibiting tRF-Glu-CTC reduced angiogenesis and hypoxia stress in the neovascular region without neuroretina toxicity in laser-induced CNV model, showing an anti-angiogenic effect comparable to bevacizumab, while overexpression of tRF-Glu-CTC significantly augmented CNV. Mechanically, under hypoxia condition, angiogenin was involved in the production of tRF-Glu-CTC, which in turn triggered endothelial cell tubulogenesis, migration and promoted the secretion of inflammatory factors via the suppression of vasohibin 1 (VASH1). When downregulating VASH1 expression, the inhibition of tRF-Glu-CTC showed minimal suppression on angiogenesis. Conclusions: This study demonstrated the important role of tRF-Glu-CTC in the progression of angiogenesis. Targeting of tRF-Glu-CTC may be an alternative to current anti-VEGF therapy for CNV in AMD and other conditions with angiogenesis.

Relationship between social interaction and health of the floating elderly population in China: an analysis based on interaction type, mode and frequency.

BACKGROUND: Although the health of the floating elderly population is an important part of active and healthy ageing, it is neglected in current Chinese society. Based on the general consensus that social interaction can affect the health of the floating population, this study explored whether the interaction type, mode and frequency influenced the health of the floating elderly population in China and investigated the variability of these influential effects. METHODS: This study used the China Migrant Population Dynamic Survey Data 2017 and selected 5239 floating elderly individuals over 60 years old. Self-rated health was used to assess the comprehensive health status of respondents. Social interaction was measured by the interaction type, mode and frequency. Descriptive statistical analysis was used to analyse the health and social interaction status. An ordinal probit model was used to estimate the influential effects and differences on health caused by social interaction. The 2SLS model was used to examine the mutual causality relationship between interaction frequency and health, and a robustness test was conducted. RESULTS: A total of 44.6% interacted with local residents, 14.2% participated in interaction activities based on geographical relations, and only 4.3% and 7% participated in interactions based on business and interest, respectively. Interacting with natives improved individuals' self-rated health by 18.5%; specifically, geographical interaction increased self-rated health by 40.9%, occupational interaction increased it by 25.2%, interest-based interaction increased it by 41.2%, and interaction frequency improved the self-rated health (ß = 0.128). In addition, sex, education level, personal income, and floating into the eastern region had a positive effect on individuals' health. However, age, spouse and hukou exerted a negative effect. CONCLUSIONS: This study demonstrated that interacting with local residents could improve the health of floating elderly population, and revealed that interest-based interaction and their frequency had a positive impact on health. The government should speed up the construction of the voluntary service system and encourage the floating elderly population to realize their personal value in social interaction. In addition, the reform of the hukou system should be further promoted, so as to remove institutional barriers to the social interaction.

Clearance of lipid droplets by chimeric autophagy-tethering compound ameliorates the age-related macular degeneration phenotype in mice lacking APOE.

Age-related macular degeneration (AMD) is the leading cause of irreversible blindness among the elderly, and there is currently no clinical treatment targeting the primary impairment of AMD. The earliest clinical hallmark of AMD is drusen, which are yellowish spots mainly composed of lipid droplets (LDs) accumulated under the retinal pigment epithelium (RPE). However, the potential pathogenic role of this excessive LD accumulation in AMD is yet to be determined, partially due to a lack of chemical tools to manipulate LDs specifically. Here, we employed our recently developed Lipid Droplets·AuTophagy Tethering Compounds (LD∙ATTECs) to degrade LDs and to evaluate its consequence on the AMD-like phenotypes in apoe-/- (apolipoprotein E; B6/JGpt-Apoeem1Cd82/Gpt) mouse model. apoe-/- mice fed with high-fat diet (apoe-/--HFD) exhibited excessive LD accumulation in the retina, particularly with AMD-like phenotypes including RPE degeneration, Bruch's membrane (BrM) thickening, drusen-like deposits, and photoreceptor dysfunction. LD·ATTEC treatment significantly cleared LDs in RPE/choroidal tissues without perturbing lipid synthesis-related proteins and rescued RPE degeneration and photoreceptor dysfunction in apoe-/--HFD mice. This observation implied a causal relationship between LD accumulation and AMD-relevant phenotypes. Mechanically, the apoe-/--HFD mice exhibited elevated oxidative stress and inflammatory signals, both of which were mitigated by the LD·ATTEC treatment. Collectively, this study demonstrated that LD accumulation was a trigger for the process of AMD and provided entry points for the treatment of the initial insult of AMD by degrading LDs.Abbreviations: AMD: age-related macular degeneration; APOE: apolipoprotein E; ATTECs: autophagy-tethering compounds; BODIPY: boron-dipyrromethene; BrM: Bruch's membrane; ERG: electroretinogram; HFD: high-fat diet; LD·ATTECs: Lipid Droplets·AuTophagy Tethering Compounds; LDs: lipid droplets; OA: oleic acid; OPL: outer plexiform layer; ROS: reactive oxygen species; RPE: retinal pigment epithelium.

Pioglitazone ameliorates retinal ischemia/reperfusion injury via suppressing NLRP3 inflammasome activities.

AIM: To explore the role of Pioglitazone (Pio) on a mouse model of retinal ischemia/reperfusion (I/R) injury and to elucidate the potential mechanism. METHODS: Retinal ischemia was induced in mice by increasing the intraocular pressure, and Pio was administered 4h though periocular injection before I/R. The number of cells in the ganglion cell layer (GCL) was counted 7d after retinal I/R injury. Glial fibrillary acidic protein (GFAP), nuclear factor-kappa B (NF-κB), p38, phosphorylated-p38, PPAR-γ, interleukin-1ß (IL-1ß), Toll-like receptor 4 (TLR4), NLRP3, cleaved caspase-1, caspase-1 were determined by real-time polymerase chain reaction and Western blotting. RESULTS: Pio promoted the survival of retinal cells in GCL following retinal I/R injury (P<0.05). Besides, retinal I/R injury stimulated the expression of GFAP and TLR4, which were partially reversed by Pio treatment (P<0.05). Retinal I/R injury-upregulated expression of NLRP3, cleaved caspase-1, IL-1ß was attenuated after Pio treatment (P<0.05). Moreover, I/R injury induced activation of NF-κB and p38 were inhibited by Pio treatment (P<0.05). CONCLUSION: Pio promotes retinal ganglion cells survival by suppressing I/R-induced activation of TLR4/NLRP3 inflammasomes via inhibiting NF-κB and p38 phosphorylation.

Nogo-B Promotes Angiogenesis in Proliferative Diabetic Retinopathy via VEGF/PI3K/Akt Pathway in an Autocrine Manner.

BACKGROUND/AIMS: Nogo-B, a conservative protein of endoplasmic reticulum, is a member of the reticulon family of proteins. Proliferative diabetic retinopathy (PDR) is the major concerning problem of diabetic retinopathy. This study explored the role of Nogo-B in the regulation of angiogenesis in PDR patients and primary human retinal endothelial cells (HRMECs). METHODS: Nogo-B was down-regulated through the use of Lentivirus-NogoB-RNAi, the effects of Nogo-B on angiogenesis under high glucose stimulation were evaluated via CCK-8 assay, wound closure assay, transwell assay, and tube formation assay. Expression of Nogo-B, VEGF, PI3K and Akt were determined by western blotting, immunofluorescence, enzyme-linked immunosorbent assay (ELISA). Co-culture systerm was used to explore cell communication. RESULTS: Nogo-B was highly enriched in ocular tissues of PDR patients and in HRMECs exposed to high glucose. Down-regulation of Nogo-B attenuated high glucose induced cell migration and tube formation in HRMECs. Mechanistically, in comparison with the negative control group, Lentivirus-NogoB-RNAi group had exhibited reduced VEGF secretion, weakened PI3K and Akt activation. Besides, high glucose treatment promoted the secretion of Nogo-B and presented as a "long-term memory". CONCLUSIONS: These data collectively indicated that Nogo-B promoted angiogenesis in HRMECs via VEGF/PI3K/Akt pathway in an autocrine manner.

Methane rescues retinal ganglion cells and limits retinal mitochondrial dysfunction following optic nerve crush.

Secondary degeneration is a common event in traumatic central nervous system disorders, which involves neuronal apoptosis and mitochondrial dysfunction. Exogenous methane exerts the therapeutic effects in many organ injury. Our study aims to investigate the potential neuroprotection of methane in a rat model of optic nerve crush (ONC). Adult male Sprague-Dawley rats were subjected to ONC and administrated intraperitoneally with methane-saturated or normal saline (10 ml/kg) once per day for one week after ONC. The retinal ganglion cells (RGCs) density was assessed by hematoxylin and eosin staining and Fluoro-Gold retrogradely labeling. Visual function was evaluated by flash visual evoked potentials (FVEP). The retinal apoptosis was measured by terminal-deoxy-transferase-mediated dUTP nick end labeling (TUNEL) assay and the expression of apoptosis-related factors, such as phosphorylated Bcl-2-associated death promoter (pBAD), phosphorylated glycogen synthase kinase-3ß (pGSK-3ß), Bcl-2 associated X protein (Bax) and Bcl-2 extra large (Bcl-xL). Retinal mitochondrial function was assessed by the mRNA expressions of peroxisome proliferator-activated receptor gamma coactivator-1α (PGC-1α), nuclear respiratory factor 1 (NRF1) and mitochondrial transcription factor A (TFAM), the mitochondrial DNA (mtDNA) copy number, citrate synthase activity and ATP content. Methane treatment significantly improved the RGC loss and visual dysfunction following ONC. As expected, methane also remarkably inhibited the retinal neural apoptosis, such as the fewer TUNEL-positive cells in ganglion cell layer, accompanied by the up-regulations of anti-apoptotic factors (pGSK-3ß, pBAD, Bcl-xL) and the down-regulation of pro-apoptotic factor (Bax). Furthermore, methane treatment suppressed up-regulations of critical mitochondrial components (PGC-1α, NRF1 and TFAM) mRNA and mtDNA copy number, as well as improved the reduction of functional mitochondria markers, including citrate synthase activity and ATP content, in retinas with ONC. Taken together, methane treatment promotes RGC survival and limits retinal mitochondrial dysfunction against ONC insult. Methane can be a potential neuroprotective agent for traumatic and glaucomatous neurodegeneration.

Toll-like receptor 4 protects against stress-induced ulcers via regulation of glucocorticoid production in mice.

Stress-induced gastric ulcer is an important life-threatening condition, while the molecular basis of its development is incompletely understood. Toll-like receptor 4 (TLR4), an innate immune pattern recognition receptor, can induce pro-inflammatory transcription, aggravating a stress ulcer. The present study found that TLR4 played a protective role in a mouse model of water immersion (23 °C) restraint stress. Wild-type (WT) and TLR4-/- male mice were respectively divided into five groups (5 per group), and exposed to the stressor for 0, 0.5, 1, 2, or 4 hours. Gastric ulcer index, determined post mortem, increased with time in both types of mice but was greater in TLR4-/- mice. Furthermore, increased serum cortisol and corticosterone concentrations were observed in WT mice only, and such increases were detected only in WT mice 4 h after lipopolysaccharide (LPS) treatment (2 mg/kg, intraperitoneal injection). Moreover, the administration of cortisol alleviated the gastric injury in TLR4-/- mice. Western blotting showed expression in the adrenal of P450scc (CYP11A1), the first rate-limiting enzyme in the synthesis of steroids, was increased 4 h after water immersion restraint stress or LPS treatment in WT mice, but was conversely decreased in TLR4-/- mice after either stressor. Furthermore, in adrenal glands of TLR4-/- mice, structural distortion of mitochondria (which contain CYP11A1) was found with electron microscopy, and lack of lipid-storing droplets was found using light microscopy on adrenal cryosections stained with Oil red O. These data indicate that TLR4 plays a protective role in stress-induced gastric ulcer that is exerted via impacting synthesis of glucocorticoid in the adrenal gland.

Overexpression of Annexin II Receptor-Induced Autophagy Protects Against Apoptosis in Uveal Melanoma Cells.

Uveal melanoma is the most common primary malignant intraocular tumor in adults and still lacks effective systemic therapies. Annexin A2 receptor (AXIIR), a receptor for Annexin II, was demonstrated to play an important role in multiple cells, but its role in uveal melanoma cells remains exclusive. Herein, the authors reported that overexpression of AXIIR was able to reduce cell viability and activate apoptosis apparently in the Mum2C uveal melanoma cell line. Meanwhile, overexpression of AXIIR could induce autophagy and increase autophagy flux. After autophagy was inhibited by chloroquine, enhanced apoptosis and cytotoxicity could be detected. In summary, these data highlighted the crucial role of AXIIR in reducing Mum2C cell viability through inducing apoptosis, while autophagy played a protective role in this process. Interference of this gene may be a promising method for uveal melanoma therapy and combination with specific inhibitor of autophagy may serve as a supplementary.

SiRNA directed against annexin II receptor inhibits angiogenesis via suppressing MMP2 and MMP9 expression.

BACKGROUND/AIMS: Annexin II receptor (AXIIR) is able to mediate Annexin II signal and induce apoptosis, but its role in angiogenesis remains unclear. This study tries to investigate the role of AXIIR in angiogenesis and the plausible molecular mechanism. METHODS/RESULTS: RNA interference technology was used to silence AXIIR, and the subsequent effects in vitro and in vivo were evaluated thereafter. Our data indicated that human umbilical vein endothelial cells (HUVECs) expressed AXIIR and knockdown of AXIIR significantly inhibited HUVECs proliferation, adhesion, migration, and tube formation in vitro and suppressed angiogenesis in vivo. Furthermore, AXIIR siRNA induced cell arrest in the S/G2 phase while had no effect on cell apoptosis. We found that these subsequent effects might be via suppressing the expression of matrix metalloproteinase 2and matrix metalloproteinase 9. CONCLUSION: AXIIR participates in angiogenesis, and may be a potential therapeutic target for angiogenesis related diseases.