An In Vitro Model of Diabetic Retinal Vascular Endothelial Dysfunction and Neuroretinal Degeneration

Background. Diabetic retinopathy (DR) is a leading cause of blindness in working-age populations. Proper in vitro DR models are crucial for exploring pathophysiology and identifying novel therapeutic targets. This study establishes a rational in vitro diabetic retinal neuronal-endothelial dysfunction model and a comprehensive downstream validation system. Methods. Human retinal vascular endothelial cells (HRMECs) and retinal ganglion cells (RGCs) were treated with different glucose concentrations with mannitol as matched osmotic controls. Cell proliferation and viability were evaluated by the Cell Counting Kit-8. Cell migration was measured using a transwell migration assay. Cell sprouting was assessed by a tube formation assay. The VEGF expression was assessed by ELISA. RGCs were labeled by neurons and RGC markers TUJ1 and BRN3A for quantitative and morphological analysis. Apoptosis was detected using PI/Hoechst staining and TUNEL assay and quantified by ImageJ. Results. Cell proliferation and migration in HRMECs were significantly higher in the 25 mM glucose-treated group ( p < 0.001 ) but lower in the 50 mM and 100 mM groups ( p < 0.001 ). The permeability and the apoptotic index in HRMECs were statistically higher in the 25 mM, 50 mM, and 100 mM groups ( p < 0.05 ). The tube formation assay found that all the parameters were significantly higher in the 25 mM and 50 mM groups ( p < 0.001 ) concomitant with the elevated VEGFA expression in HRMECs ( p = 0.016 ). Cell viability was significantly lower in the 50 mM, 100 mM, and 150 mM groups in RGCs ( p 50 mM = 0.013 , p 100 mM = 0.019 , and p 150 mM = 0.002 ). Apoptosis was significantly elevated, but the proportion of RGCs with neurite extension was significantly lower in the 50 mM, 100 mM, and 150 mM groups ( p 50 mM < 0.001 , p 100 m M < 0.001 , and p 150 mM < 0.001 ). Conclusions. We have optimized glucose concentrations to model diabetic retinal endothelial (25-50 mM) or neuronal (50-100 mM) dysfunction in vitro, which have a wide range of downstream applications.

Vascular endothelium protective property of curcumin

Objectives: In the present study, we aimed to examine the efficacy of curcumin on endothelial vascular protection on human umbilical vein endothelial cells (HUVEC) cells in the in vitro setting and to determine effective doses. Materials and methods: Cytotoxic effect and wound healing activity of curcumin on the HUVEC cell line were evaluated and angiogenesis was studied by tube formation assay. The cytotoxic activity of 0.5 to 8 μM curcumin on HUVEC cell line was tested using the WST-1 cell proliferation assay. In wound healing determination, the scratched cells were incubated with the half maximal effective concentration (EC50) dose of curcumin and wounds were monitored by the JuLITM Br live cell movie analyzer. Wound gaps were measured using the ImageJ software. To determine the angiogenesis, tube formation assay was performed and the results were analyzed. Results: The 1.77 μM of curcumin increased the cell viability by 150% after 48 h of treatment. According to the wound healing results, after 48 h of incubation, the control group and 1.77 μM curcumin exhibited 47.1% and 43.8% closure, respectively. The mean maximum and minimum tube lengths were found to be 21,858±3,945 and 12,438±3,817 pixel for curcumin, respectively with low fetal bovine serum (FBS) and curcumin with high FBS, respectively. Conclusion: Our results show that curcumin is a promising endothelial protective agent for HUVEC cell line.

Thermal stress involved in TRPV2 promotes tumorigenesis through the pathway of PI3K/Akt/mTOR in esophageal squamous cell carcinoma

BackgroundEsophageal squamous cell carcinoma (ESCC) is a leading cause of cancer death worldwide. Although the exposure of esophageal mucosa to heat stimuli has long been recognized as an important risk for the initiation and development of ESCC, its underlying mechanisms remain uncharacterized. MethodsWestern blotting and immunofluorescence were used to detect the expression and localization of transient receptor potential vanilloid receptor 2 (TRPV2) in the ESCC cells. The cancerous behaviors of the ESCC cells were evaluated by a single-cell culturing assay, a wound healing assay, a 3D culturing assay and a tube formation assay respectively. In vivo tumorigenicity and metastasis of the ESCC cells were examined via xenograft nude mouse models. Western blotting and IHC were performed to determine the expression profiles of TRPV2 in the ESCC patient tissues. TRPV2 knocked-out ESCC cell line was established using CRISPR-Cas9 gene editing technique.ResultsHere, we found that the expression of TRPV2, one of the thermally sensitive TRP family members, was upregulated in both ESCC cells and clinical samples. We further showed that activation of TRPV2 by recurrent acute thermal stress (54°C, a temperature unexpectedly much lower than those in many dietary modalities) or O1821 (20 μM), a TRPV2 agonist, promoted cancerous behaviors in ESCC cells. The proangiogenic capacity of the heat-challenged ESCC cells was also found to be enhanced profoundly in the tube formation assay; both tumor formation and metastasis that originated from the cells were substantially promoted in nude mouse models upon the activation of TRPV2. These effects were inhibited significantly by tranilast (120 μM), a TRPV2 inhibitor, and abolished by TRPV2 knock-out using CRISPR-Cas9 gene editing. Conversely, overexpression of TRPV2 by transfection of TRPV2 DNA into NE2 cells, could switch the cells to tumorigenesis upon activation of TRPV2. Mechanistically, the driving role of TRPV2 in the progression of ESCC is mainly regulated by the PI3K/Akt/mTOR signaling pathway. Application of a pan-PI3K/mTOR inhibitor and/or a PTEN activator resulted in markedly reduced ESCC cell proliferation. ConclusionsOur study first proved that TRPV2 plays an important role in the tumorigenesis of ESCC upon thermal stress. We revealed that TRPV2-PI3K/Akt/mTOR is a novel and promising target for the prevention and treatment of ESCC.

Abstract 466: Vascular Claudin-11 Plays a Protective Role for Human Atherosclerosis Progression

Background and Aims: The expression and the role of tight junction protein, Claudin-11 (CLDN11) in vasculat smooth muscle cell (vSMC) is unknown. Methods: To understand the role of CLDN11 in the vSMC, we transfected siRNA-CLDN11 into human coronary vascular smooth muscle cell line (hCSMC). cDNA microarray using Agilent Human mRNA arrays, immunocytochemistry, tube formation assay, FACS, and cell cycle analysis were performed 7 days after CLDN11 knock-down. To know the role of CLDN11 in the human cardiovascular system, we obtained vascular smooth muscle layer from autopsied left anterior descending artery and CLDN11 mRNA expression was evaluated following modified AHA Consensus Classification Based on Morphologic Descriptions (three groups, total n=45). Results: CLDN11 was well expressed in vascular smooth mucscle layer in immunohistochemisty and western blot analysis. We observed the angiogenesis (CXCL8, SOX17, HEY1), cell proliferation (EGR3, ITGB2), and extracellular matrix (BMPER, WNT1) associated gene expression. Following CLDN11-siRNA transfection, the tube formation assay and proliferating cellular phase was markedly increased in siRNA treatment group (p<0.01, respectively). In the human sample, CLDN11 expression was inversely correlated with the progression of coronary atherosclerosis (p=0.0026), and the sudden cardiac death with complicated coronary atherosclerosis (p<0.05). Conclusions: These results indicate that CLDN11 could tightly regulate the vascular smooth muscle physiology. And CLDN11 might play a certain role for atherosclerosis propagation to regulate the vSMCs plasticity and possible new etiology for cardiovascular events.

AB0089 THE ANALYSIS FOR THE INHIBITION OF ANGIOGENESIS BY JAK INHIBITOR

Background:Many blood vessels are generated in the hyperplastic synovial tissue of patients with rheumatoid arthritis (RA), and lead to chronic tissue inflammation and joint destruction [1]. Janus kinase (JAK) family consisting of JAK1, JAK2, JAK3 and tyrosine kinase 2 (TYK2) are chain receptors which phosphorylate signal transducers and activators of transcription (STAT) and mediate inflammatory diseases including RA [2]. Nowadays, several JAK inhibitors such as Tofacitinib (TOF), Baricitinib (BAR) and Peficitinib (PEF) have been developed and demonstrated to have the inhibitory effects on inflammatory arthritis [3-5]. However, there were few reports concerning their effects on angiogenesis in vitro.Objectives:The purpose of the present study is to investigate the influence of JAK inhibitors on angiogenesis of human umbilical vein endothelial cell (HUVEC) activated by vascular endothelial growth factor (VEGF).Methods:The cell line of HUVECs were used for this study. The activity of proliferation and tube formation were analyzed by counting assay and tube formation assay, respectively.In counting assay, HUVECs (5 × 104cells/ml) were seeded onto 96-well cell culture plate with 20 ng/ml VEGF including various doses (0.1µM, 1µM, 5µM) of TOF, BAR or PEF. After 48 hours incubation at 37°C in a humidified atmosphere containing 5% CO2, cell proliferation of each groups was assessed using cell counting kit. In tube formation assay, HUVECs (5 × 104cells/ml) were treated with 20ng/ml VEGF including various dose (0.1µM, 1µM, 5µM) of TOF, BAR or PEF for 00 hours, then seeded onto 48-well plate applied with Matrigel. After 24 hours incubation on Matrigel, the capillary-like tube formation of each well was photographed using phase contrast microscopy. Tube formation were quantitated by measurement of the length of branch.Results:HUVECs were activated in proliferation and tube formation by VEGF treatment. And, the proliferation and tube formation of HUVECs activated by VEGF were suppressed by All of TOF, BAR and PEF. In particular, TOF and PEF could suppress them highly.Conclusion:This study showed the inhibitory effect of JAK inhibitors on proliferation and tube formation of HUVECs activated by VEGF. In particular, the angiogenesis of HUVECs activated by VEGF was highly suppressed by TOF and PEF. VEGF is reported to regulate the angiogenesis through multi JAK-STAT signaling pathways [6]. The inhibitory effects on angiogenesis of TOF, BAR and PEF might depend on the differences in their affinity for JAKs. VEGF has been shown to a have a central involvement in the angiogenic process in RA [7]. JAK inhibitors might suppress the angiogenesis in RA synovial tissues by inhibiting VEGF signaling.References:[1]Scott DL, et al. Rheumatoid arthritis. Lancet. 2010.[2]Banerjee S, et al. JAK-STAT signaling as a target for inflammatory and autoimmune diseases: current and future prospects. Drugs. 2017.[3]William D, et al. JAK inhibitors in dermatology: the promise of a new drug class. Journal of the American Academy of Dermatology. 2017.[4]Dhillon S. Tofacitinib: A Review in Rheumatoid Arthritis. Drugs. 2017.[5]Markham A, et al. Peficitinib: First Global Approval. Drugs. 2019.[6]Zhang HY, et al. Three important components in the regeneration of the cavernous nerve: brain-derived neurotrophic factor, vascular endothelial growth factor and the JAK/STAT signaling pathway. Asian journal of andrology. 2011.[7]Paleolog EM. Angiogenesis in rheumatoid arthritis. Arthritis research. 2002.Acknowledgments:noneDisclosure of Interests:None declared