Aurora kinase B disruption suppresses pathological retinal angiogenesis by affecting cell cycle progression.

PURPOSE: The detrimental effects of pathological angiogenesis on the visual function are indisputable. Within a prominent role in chromosome segregation and tumor progression, aurora kinase B (AURKB) assumes a prominent role. However, its role in pathological retinal angiogenesis remains unclear. This study explores this latent mechanism. METHODS: To inhibit AURKB expression, we designed specific small interfering RNAs targeting AURKB and transfected them into vascular endothelial cells. Barasertib was selected as the AURKB inhibitor. The anti-angiogenic effects of both AURKB siRNA and barasertib were assessed in vitro by cell proliferation, transwell migration, and tube formation. To evaluate the angiogentic effects of AURKB in vivo, neonatal mice were exposed to 75% oxygen followed by normoxic repositioning to establish an oxygen-induced retinopathy (OIR) model. Subsequently, phosphate-buffered saline and barasertib were administered into OIR mice via intravitreal injection. The effects of AURKB on cell cycle proteins were determined by western blot analysis. RESULTS: We found that AURKB was overexpressed during pathological angiogenesis. AURKB siRNA and barasertib significantly inhibited endothelial cell proliferation, migration, and tube formation in vitro. Furthermore, AURKB inhibition attenuated retinal angiogenesis in the OIR model. A possible mechanism is the disruption of cell cycle by AURKB inhibition. CONCLUSION: In conclusion, AURKB significantly influenced pathological retinal angiogenesis, thereby presenting a promising therapeutic target in ocular neovascular diseases.

Effect of intraocular anti-VEGF on cystoid macular edema associated with Henoch-Schonlein purpura-a case report.

BACKGROUND: To report a bilateral cystoid macular edema associated with Henoch-Schonleinpurpura. CASE PRESENTATION: A 21-year-old man presented a bilateral, painless, and bilateral blurred vision for 5 weeks with visual acuity (VA) of 6/12 on the right eye and 6/48 on the left. FA and OCT showed bilateral cystoid macular edema, and the fundus photograph showed retinal hemorrhages. Using intravenous dexamethasone could reduce macular edema, but it reoccurred shortly after switching to oral prednisone. Repeated intraocular injection of anti-VEGF in both eyes was performed and VA improved to 6/6 on the right eye and 6/7.5 on the left with the regression of edema after 6 months follow-up. CONCLUSIONS: Intraocular anti-VEGF might be an alternative choice to glucocorticoid in cases of bilateral cystoid macular edema associated with Henoch-Schonlein purpura.

Hexabromocyclododecanes promoted autophagy through the PI3K/Akt/mTOR pathway in L02 cells.

As additive brominated flame retardants, hexabromocyclododecanes (HBCDs) are being widely used in diverse artificial materials and products, including thermal insulation building materials, housings of electronic equipment, and upholstery textiles. Toxicology studies have shown that HBCDs exposure are closely related to hepatotoxicity and liver diseases. The present study is designed to explore how HBCDs affect cell apoptosis and autophagy process in a human hepatocyte cell line (L02) and to reveal the underline molecular mechanisms. Firstly, HBCDs could elevate the apoptosis rate of L02 cells dose-dependently. Three apoptosis related proteins (apoptotic protease activating factor 1 (Apaf-1), cysteinyl aspartate specific proteinase 3 (caspase-3) and cysteinyl aspartate specific proteinase 9 (caspase-9)) were observed to be up-regulated using western blotting method. Autophagy process was also started by HBCDs in L02 cells as indicated by the increased expressions of LC3-phosphatidylethanolamine conjugate (LC3-II) and other autophagic protein markers (Beclin-1, autophagy related protein 3 (Atg3), autophagy related protein 5 (Atg5), autophagy related protein 7 (Atg7) and autophagy related protein 16L1(Atg16L1)). The results of the green fluorescent protein (GFP)-microtubule-associated protein 1 light chain 3 (LC3) intracellular localization and fluorescence intensity further evidenced the activation of autophagy in L02 cells after treated with HBCDs. In addition, phosphatidylinositide 3-kinases/protein kinase B/mammalian target of rapamycin (PI3K/Akt/mTOR) pathway was activated in L02 cells by HBCDs, suggested by the increased expressions of related proteins. The inhibitors of PI3K (LY294002), DNA-activated protein kinase catalytic subunit (DNA-PKcs) (NU7441), Akt (MK2206), and mTOR (KU0063794) could obviously reduce the autophagic proteins prompted by HBCDs. The fluorescence intensities of GFP-LC3 transfected L02 cells were also decreased significantly after the application of these inhibitors. These results indicated that PI3K/Akt/mTOR pathway was participated in regulating autophagy process promoted by HBCDs. In above, HBCDs could induce mitochondrial-dependent apoptosis and autophagy in L02 cells, which was modulated by PI3K/Akt/mTOR pathway.

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.

Novel approach by natural language processing for COVID-19 knowledge discovery.

BACKGROUND: The impact of COVID-19 on public health has mandated an 'all hands on deck' scientific response. The current clinical study and basic research on COVID-19 are mainly based on existing publications or our knowledge of coronavirus. However, efficiently retrieval of accurate, relevant knowledge on COVID-19 can pose significant challenges for researchers. METHODS: To improve quality in accessing important literature findings, we developed a novel natural language processing (NLP) method to automatically recognize the associations among potential targeted host organ systems, associated clinical manifestations, and pathways. We further validated these associations through clinician experts' evaluations and prioritize candidate drug targets through bioinformatics network analysis. RESULTS: We found that the angiotensin-converting enzyme 2 (ACE2), a receptor that SARS-CoV-2 required for cell entry, is associated with cardiovascular and endocrine organ system and diseases. Furthermore, we found SARS-CoV-2 is associated with some important pathways such as IL-6, TNF-alpha, and IL-1 beta-induced dyslipidemia, which are related to inflammation, lipogenesis, and oxidative stress mechanisms, suggesting potential drug candidates. CONCLUSION: We prioritized the list of therapeutic targets involved in antiviral and immune modulating drugs for experimental validation, rendering it valuable during public health crises marked by stresses on clinical and research capacity. Our automatic intelligence pipeline also contributes to other novel and emerging disease management and treatments in the future.

Laser Capture Microdissection-Based RNA Microsequencing Reveals Optic Nerve Crush-Related Early mRNA Alterations in Retinal Ganglion Cell Layer.

Purpose: To establish a method of laser capture microdissection (LCM) and RNA microsequencing for exploring optic nerve crush (ONC)-related early mRNA alterations in retinal ganglion cell (RGC) layer. Methods: An LCM protocol was developed using retinal tissue sections to obtain high-quality RNA for microsequencing. Cells in the RGC layer were collected by laser pressure catapulting (LPC) using a PALM Zeiss UV LCM system. The effect of section thickness and slide type on tissue capture success and RNA yield and the integrity after LCM were evaluated. The optimal LCM protocol was used to explore ONC-related early mRNA alterations in the RGC layer. Candidate genes were validated by real-time polymerase chain reaction of the RGC layer tissue dissected by "cut and LPC" using the same LCM system. Results: We successfully established an optimal LCM protocol using 30-µm-thick retinal tissue sections mounted on glass slides and laser pressure catapulting (LPC) to collect cells in the RGC layer and to obtain high-quality RNA for microsequencing. On the basis of our protocol, we identified 8744 differentially expressed genes that were involved in ONC-related early mRNA alterations in the RGC layer. Candidate genes included Atf3, Lgals3, LOC102551701, Plaur, Tmem140, and Maml1. Conclusions: The LCM-based single-cell RNA sequencing allowed a new sight into the early mRNA changes of RGCs highlighting new molecules associated to ONC. Translational Relevance: This technique will be helpful for more accurate transcriptome analysis of clinical pathological samples of ophthalmology and provide important reference for the discovery of new pathological diagnosis indicators and drug development targets.

Vascular endothelial growth factor upregulates expression of annexin A2 in vitro and in a mouse model of ischemic retinopathy.

PURPOSE: Annexin A2 has been shown to play a role in many neovascularization diseases. We investigated the effect of vascular endothelial growth factor (VEGF) on annexin A2 expression and related intracellular signaling mechanisms in a mouse model of ischemia-induced retinal neovascularization. METHODS: Annexin A2 expression and the effect of vascular endothelial growth factor (VEGF) on annexin A2 ex pression in retinal neovascularization were assayed by real-time PCR, western blot analysis. The effect of Annexin A2 on retinal neovascularization were assayed by siRNA interference and overexpression of Annexin A2, fluorescence imaging, and immunofluorescence histochemistry in a mouse model of ischemia-induced retinal neovascularization. RESULTS: Expression of annexin A2 mRNA and protein were increased in the mouse model of ischemia-induced retinal neovascularization and in RF/6A cells treated with VEGF. In RF/6A cells, increased expression of annexin A2 was inhibited by the VEGF receptor 2 (VEGFR2) inhibitor SU10944, and by anti-VEGFR2 neutralizing antibody, and was increased by VEGF. Mice with ischemic retinopathy showed increased expression of annexin A2 in vascular endothelial cells, and enhanced retinal neovascularization after intraocular injection of an adenoviral vector containing an annexin A2 expression cassette. Conversely, annexin A2 knockdown suppressed retinal neovascularization in these mice. CONCLUSIONS: These findings suggest that annexin A2 might induce retinal neovascularization through a VEGF-VEGFR2 pathway in ischemia-induced retina neovascularization. Therefore, annexin A2 is an angiogenesis activator and may be a potential target for the development of effective therapeutic strategies for the treatment of retinal neovascularization.

UMSC-derived exosomes promote retinal ganglion cells survival in a rat model of optic nerve crush.

Traumatic optic neuropathy or glaucoma lead to retinal ganglion cells loss and cause blindness, and there is no effective therapy strategy by far. Mesenchymal cells from the Wharton's jelly of the umbilical cord (umbilical cord mesenchymal stem cells, UMSCs) and UMSC-derived exosomes (UMSC-Exos) are promising candidates for allogeneic therapy in regenerative medicine, but their effort on optic nerve injury and the underlying mechanism remains undefined. In the present study, we investigated the functions of UMSC-Exos in a rat optic nerve crush (ONC) model. After three times of treatments with an interval of one week, we found that the UMSC-Exos significantly promoted Brn3a+ retinal ganglion cells (RGCs) survival in retinal ganglion cell layer compared with PBS controls. UMSC-Exos also significantly promoted GFAP+ glia cells activation in retina and optic nerve. However, no increase of GAP43+ axon counts in the optic nerve was found after UMSC-Exos treatment. Thus, our results demonstrate that UMSC-derived exosomes may play a role in neuroprotection by promoting the RGCs survival and glia cells activation but not the axon regeneration.

Economic evaluation of the air pollution effect on public health in China's 74 cities.

Air deterioration caused by pollution has harmed public health. The existing studies on the economic loss caused by a variety of air pollutants in multiple cities are lacking. To understand the effect of different pollutants on public health and to provide the basis of the environmental governance for governments, based on the dose-response relation and the willingness to pay, this paper used the latest available data of the inhalable particulate matter (PM10) and sulphur dioxide (SO2) from January 2015 to June 2015 in 74 cities by establishing the lowest and the highest limit scenarios. The results show that (1) in the lowest and highest limit scenario, the health-related economic loss caused by PM10 and SO2 represented 1.63 and 2.32 % of the GDP, respectively; (2) For a single city, in the lowest and the highest limit scenarios, the highest economic loss of the public health effect caused by PM10 and SO2 was observed in Chongqing; the highest economic loss of the public health effect per capita occurred in Hebei Baoding. The highest proportion of the health-related economic loss accounting for GDP was found in Hebei Xingtai. The main reason is that the terrain conditions are not conducive to the spread of air pollutants in Chongqing, Baoding and Xingtai, and the three cities are typical heavy industrial cities that are based on coal resources. Therefore, this paper proposes to improve the energy structure, use the advanced production process, reasonably control the urban population growth, and adopt the emissions trading system in order to reduce the economic loss caused by the effects of air pollution on public health.

Annexin A2 silencing enhances apoptosis of human umbilical vein endothelial cells in vitro.

OBJECTIVE: To study the effects of inhibited Annexin A2 (ANXA2) on human umbilical vein endothelial cells (HUVECs) in vitro. METHODS: Short hairpin RNA (shRNA) targeting ANXA2 was designed and cloned into double marked lentivirial vector GV248 for RNAi to generate the recombinant expression plasmids, which were stably transfected into HUVECs. The protein and mRNA expression levels of ANXA2 were analyzed by western blotting and real-time polymerase chain reaction, respectively. Cell proliferation (cell counting kit-8 assay), apoptosis (flow cytometry analysis), the expression (western blotting) and the activity of caspases (enzyme-linked immunosorbent assay) were used to assess the effects of silencing ANXA2 on HUVECs in vitro. RESULTS: The plasmids to express ANXA2-specific shRNA were constructed and were infected into HUVEC resulting in the stably transfected experimental (ANXA2-shRNA), control (control-shRNA) and mock (no plasmid) cell lines, which were verified with western blot and real-time PCR. HUVEC/ANXA2-shRNA showed an inhibition rate 91.89% of ANXA2 expression compared to the mock HUVEC. ANXA2 silencing cell strain obviously presented a lower cell proliferation activity compared to the control and mock HUVECs, with an inhibition rate 82.35% on day 7 in vitro. FACS analysis indicated that the HUVEC/ANXA2-shRNA cells undergoing apoptosis increased by 102.61% compared to the mock HUVECs (P < 0.01). Moreover, the activity levels of caspase-3, caspase-8 and caspase-9 in HUVEC/ANXA2-shRNA cells were increased and the activated cleaved caspase-3, cleaved caspase-8 and cleaved caspase-9 were upregulated evidently compared with that of the control and mock HUVECs by 56.29%, 89.59% and 144.58% (P < 0.01). CONCLUSIONS: shRNA-mediated silencing of ANXA2 could not only be able to suppress HUVECs proliferation but to upregulate the enzyme activity of caspases, which bring to an increase of cell apoptosis. This work suggested that ANXA2 may represent a useful target of future molecular therapies.

Annexin A2 promotes choroidal neovascularization by increasing vascular endothelial growth factor expression in a rat model of argon laser coagulation-induced choroidal neovascularization.

BACKGROUND: Choroidal neovascularization (CNV) is a common cause of visual loss in the elderly patients with age-related macular degeneration and represents the growth of subretinal new vessels in the macular region. This study aimed to investigate the relationship between annexin A2 (ANXA2) and vascular endothelial growth factor (VEGF) in CNV. METHODS: In a rat model of argon laser coagulation-induced CNV, the mRNA expressions of the annexins and VEGF protein expression in the retina were detected using fluorescent real-time polymerase chain reaction (PCR) and immunohistochemistry, respectively. The interactions between ANXA2 and VEGF in both a retinal pigment epithelial cell line RPE-J and the rat model of CNV were examined by means of RNA interference, real-time PCR, Western blotting, enzyme-linked immunosorbent assay (ELISA) and histopathological examinations. RESULTS: Fundus fluorescein angiography (FFA) showed that argon laser coagulation of the retina induced stable CNV models in the rats. Two to three weeks after the coagulation, ANXA2 and VEGF expressions in the coagulated area in the retina and choroid increased to the peak level, while the other annexin members (ANXA4, ANXA5, ANXA7 and ANXA11) showed no obvious changes. In RPE-J cells and the CNV model, RNA interference of ANXA2 gene significantly lowered the VEGF protein and mRNA expressions, and application of an adenoviral vector containing ANXA2 gene markedly increased VEGF expressions in the rat model of CNV, but produced no significant effects on the expressions of the kinase insert domain-containing receptor (KDR) or the fms-like tyrosine kinase (Flt-1). The expression of KDR inhibited the increment in ANXA2 expression, but VEGF and Flt-1 did not directly affect ANXA2 expression. CONCLUSION: Besides the role as a plasminogen and the receptor of tissue plasminogen activator, ANXA2, which is under regulation of KDR via a negative feedback mechanism, also participates in neovascularization by regulating VEGF expression through a positive feedback mechanism.